I wonder if users of Shell’s gasification technology in China have created their own question banks

I have here a question bank from a certain factory for your reference. Gasification Question Bank I. Basic Concepts and Unit Conversions 1. What are ash fusion point and the viscosity-temperature properties of ash? The ash fusion point is the temperature at which coal ash softens and melts. The viscosity-temperature property refers to the fluidity of the liquid ash formed when the ash content of coal melts at different temperatures, and it is generally expressed as ash viscosity. 2. What is the grindability of coal? The grindability of coal indicates the ease with which it can be crushed, and it is commonly expressed by the Hargreaves Grindability Index (HGI). 3. What is the reactivity of coal? The reactivity of coal refers to its ability to react with various gasification agents (such as CO2, H2, and water vapor) under certain conditions. It is usually determined at a specific temperature by introducing CO2 at a certain flow rate, with the reduction rate of CO2 being used as an indicator of the coal’s reactivity. The higher the reduction rate of CO2, the better the activity of the coal. 4. What is the stability of coal slurry? The stability of water-coal slurry refers to the ability of coal particles to remain suspended in water. Typically, the coal slurry is left to stand in a container for 24 hours, and this is expressed as the water separation rate of the coal slurry. The higher the water separation rate, the poorer the stability of the coal slurry. 5. What is the total oxygen-to-coal ratio? The oxygen-coal ratio refers to the volume ratio of oxygen to coal slurry. 6. What is specific oxygen consumption, and what is specific coal consumption? The amount of pure oxygen consumed per 1000 Nm3 of (CO+H2) produced is known as the specific oxygen consumption. Nm3/1000Nm3: The amount of dry coal consumed per 1000 Nm3 of (CO+H2) produced is referred to as the specific coal consumption. kg/1000Nm3 7. What is cold gas efficiency? The ratio of the carbon content of the combustible gases in syngas to the total carbon content. 8. What is carbon conversion rate? It refers to the ratio of the carbon content in syngas to the carbon content in coal. 9. What is soft water? That is, softened water. It refers to water from which Ca2+ and Mg2+ ions have been removed, with the required water hardness being ≤0.02 mmol/t. 10. What is desalinated water? Desalinated water refers to water from which anions and cations have been removed using ion exchange. The indicators are: conductivity ≤ 10 s/cm, SiO2 ≤ 100 g/t. 11. What is pressure? Pressure is the force acting perpendicularly on a unit area. 12. What is gauge pressure? Absolute pressure? Vacuum level? What is the relationship among the three? The pressure in absolute vacuum is called absolute volume pressure, while the pressure measured with respect to absolute zero pressure is called absolute pressure. The reading on a pressure gauge used to measure fluid pressure is called gauge pressure, which is the difference between the absolute pressure of the fluid and the atmospheric pressure at that location. If the absolute pressure of the fluid being measured is lower than atmospheric pressure, the pressure indicated by the gauge will be negative, and this value is referred to as vacuum level. P_gauge pressure = P_absolute pressure – P_atmospheric pressure. P_vacuum = P_atmospheric pressure – P_absolute pressure. 1 Pa = 1 N/m2. 1 MPa = 106 Pa. 1 mmHg = 133 Pa. 1 mmH2O = 9.81 Pa. 1 kgf/cm2 = 9.8066×104 Pa. 1 atm = 1.013×105 Pa. 13. What is vaporization? The process by which a substance changes from a liquid state to a gaseous state is called vaporization. 14. What is throttling? The phenomenon in which, as a fluid flows through a pipe, its flow velocity increases suddenly and pressure decreases due to a sudden reduction in the cross-sectional area of the channel is called throttling. II. Principles and Key Operating Points of Basic Equipment 1. What are the main components inside the washing tower T1301? The internal components of the wash tower T1301 mainly include downcomers, upcomers, gas lift hoods, four impact trays, downflow pipes, and a baffle-type demister. 2. What is the working process of the scrubber tower T1301? The gas-liquid mixture entering T1301 from the Venturi scrubber X1301 passes through the downcomer to the lower part of the scrubber tower T1301; after passing through the water bath, the gas rises along the upcomer and continues to ascend after being deflected by the rising gas hood, while the water and most of the solid particles remain in the water. The process condensate from the process condensate tank V1302 further washes the gas through the tray columns. Finally, the gas exits the scrubber tower T1301 after the entrained liquid and ash have been removed by a demister. 3. What is the function of the demister at the top of the scrubber tower? The function of the demister is to prevent the entrainment of mist, remove water and ash, and avoid the syngas from carrying water into the shift system and damaging the catalyst. 4. What is the function of the trays inside the wash tower T1301? The tray inside T1301 is an impact-type tray; its function is to increase the contact area between the gas and liquid phases, thereby more effectively reducing the temperature of the syngas and further washing it to remove fine ash particles from it. 5. What are the common types of defoamers? What is its working principle? Commonly used defoamers include baffle type, mesh type, centrifugal type, and cyclone separation type. They are all captured through the inertial impact of droplet motion against metal objects or walls. 6. What is the function of the sedimentation tank V1308? The function of the sedimentation tank V1308 is to separate cleaner graywater from the black water, as well as slurry with a high solid content. 7. What is the working principle of a sedimentation tank? The sedimentation of particles in the sedimentation tank can be roughly divided into two stages. A distance below the feed inlet, the particle concentration is very low, and the particles settle essentially freely. At the bottom of the sedimentation tank, the particle concentration gradually increases; the particles settle in a turbulent manner at a very slow rate. A coagulant is added to the sedimentation tank to accelerate settling, and the yield of the clear liquid from the tank depends on its diameter. 8. What is the working process of a sedimentation tank? Settling tank V1308 is a continuous gravity settler. Slag water is continuously added below the liquid level at the center of the sedimentation tank, where it then spreads across the entire cross-section of the tank. The liquid flows upward, while the clear liquid overflows from the edges; solid particles gradually settle to the bottom of the tank. The bottom of the tank is equipped with slowly rotating toothed rakes that gradually move the sediment to the central sludge pit, where it is continuously removed via a slurry pump through the outlet pipe at the bottom. 9. What is the structure of the agitator X1303 in the sedimentation tank? The sedimentation tank mixer X1303 includes a girder, a transmission device, a drive shaft, a main motor, a lifting motor, a scraper, etc. 10. How is the agitator X1303 in the sedimentation tank automatically controlled? The sedimentation tank mixer X1303 features lifting and overload protection. In automatic mode, pressing the start button activates the main motor of the sludge scraper, causing the sludge scraping rake to operate properly. When the sludge-scraping resistance becomes too high, reaching 85% of the rated torque, the lifting mechanism is activated; when the resistance is less than 85% of the rated torque, the lifting motor stops and the sludge-scraping rake ceases to rise. When the resistance reaches 100% of the rated torque, the main motor stops, the sludge-scraping rake is raised to its maximum height, and an alarm is sent to the centralized control room. 11. What is the function of a mixer? The function of the stirrer is: (1) mixing liquids that are soluble in each other ； ⑵ Dispersion and contact of immiscible liquids ； ⑶ gas-liquid contact ； ⑷ Suspension of solid particles in a liquid ； ⑸ Enhance heat transfer between the liquid and the pipe wall. 12. What are the common categories of mixers? ⑴ Impeller type: Essentially a shellless axial flow pump, suitable for mixing processes aimed at achieving uniformity on a macro scale. ⑵ Turbine type: Essentially a centrifugal pump without a pump casing, suitable for mixing processes that require uniformity on a small scale. ⑶ Large blades: low-speed mixer. Including paddle, frame, and screw types, suitable for stirring high-viscosity liquids. 13. What are the main components of a mixer? The mixer is mainly composed of a motor, a reduction gearbox, a coupling, a mixing shaft, blades, and a mounting base. 14. What types of refractory bricks are used in the gasification furnace? ⑴ Fire-facing bricks: High-chromium bricks ZIRCHROM90, medium-chromium bricks ZIRCHROM60. (2) Support bricks: Low-chromium bricks CHROMCOR12. (3) Insulating bricks: High-alumina bricks MS6 (super-performance refractory bricks SDFB), 28–155 (insulating refractory bricks). 15. How many layers does the refractory lining of a gasification furnace have? ⑴ Three layers in the gasifier neck: ① Compressible layer (refractory felt) ② Insulating bricks (MS6) ③ Fire-facing bricks (ZIRCHROM60). ⑵ Three layers of the vault: ① Compressible layer (Superstick compressible refractory material) ② Cast layer (high-density refractory concrete) ③ Fire-facing brick (ZIRCHROM60). ⑶ Four layers of the vertical furnace wall: ① Compressible layer (refractory felt) ② Insulating bricks (SDFB IFB) ③ Support bricks (CHROMCOR12) ④ Fire-facing bricks (ZIRCHROM60, 90). ⑷ Three layers in the cone and taphole area: ① pouring layer (high-density refractory concrete) ② support plate (CHROMCOR12) ③ fire-facing brick (ZIRCHROM60). 16. What is the function of the two support brackets in the conical section of the combustion chamber of the gasifier? The upper support bracket is used to support the support bricks, while the lower support bracket is used to support the fire-facing bricks. 17. What is the structure of the gasification furnace? The water-coal slurry gasifier was developed by Texaco in the United States based on improvements to heavy oil gasifiers. It uses a cylindrical furnace, which is divided into a combustion chamber and a quenching chamber. 18. What is the structure of the combustion chamber in a gasifier? The combustion chamber of the gasifier is a steel container lined with refractory material; a process burner is mounted at its top, and a quenching chamber is connected to the lower part of the conical shape. The refractory bricks inside the furnace are divided into three separate sections: the vault, the cylinder, and the cone, and they can be replaced locally without the need for support from one another. There is a temperature measurement system on the furnace wall surface, and high-temperature thermocouples are installed in the furnace chamber to guide the operation of the gasification furnace. 19. What is the structure of the quench chamber in a gasification furnace? The upper part of the gasifier quench chamber is the combustion chamber, which is connected below to a lockhopper. Its internal components mainly include a quenching ring, downcomer, upcomer, and separation baffle. 20. How does the quench ring work? The quenching water enters the annular flow channels of the quenching ring through four paths, then passes through openings in the side walls of these channels to reach the inside of the quenching ring, and subsequently flows downward evenly along the gap between the ring and the downcomer, forming a water film on the wall of the downcomer. 21. How is the quench ring connected to the support plate and the downcomer? The quenching ring is connected to the support plate via flanges, while the quenching ring tube is welded to the downcomer. 22. What is the function of a gasification furnace? The gasifier is a key component of the gasification system. Oxygen and water-coal slurry are rapidly atomized in the combustion chamber using process burners, where a partial oxidation reaction takes place, generating a large amount of heat. This results in the formation of gas composed mainly of CO and H2. After being cooled by water and having its dust removed preliminarily, this gas exits the gasifier’s cooling chamber along with the steam generated during gasification. 23. What are the main causes of gas leakage from the synthesizer in the quench chamber of the gasification furnace? ⑴ Leakage at the flange connecting the quench ring and the support plate. ⑵ The downcomer has burned through. ⑶ The downcomer has fallen off. 24. What is the structure of a process burner? The process burner features a three-channel external mixing design, with oxygen flowing through the central tube and the outer annular gap. A cooling coil is installed at the burner head, along with a water jacket at the front end, to protect the burner from damage in high-temperature environments. 25. What are the causes of damage to process burners? Process burners generally last for 1.5 to 2 months; when replaced, the nozzle head is cut off and subjected to surfacing treatment. The main reasons for their damage are: (1) Wear of the nozzle due to the erosion by coal particles moving at a certain speed. ⑵ Backflow in the gasifier causes ablation. 26. What are the main components of a torch? The flare is mainly composed of a flare tip, a nitrogen seal tank, a cylinder, a flare frame, a water seal tank, and an ignition device. 27. What is the function of the nitrogen seal tank in the torch system? The tank is equipped with a lift pipe; since nitrogen molecules, which are sealed in, have a lower molecular weight than air, they float above the lift pipe. This arrangement prevents air from flowing back into the flare tube in the event that gas emission is interrupted, thus ensuring that no backflow or explosion occurs during subsequent emissions. 28. What is the function of the torch system? The flare system is a safety discharge facility to prevent air pollution and poisoning incidents among personnel. 29. What is the structure of the starting extractor? The starting extractor is a steam jet pump, which mainly consists of a gas inlet, a steam inlet, an outlet, a nozzle, and a diffuser. 30. What are the characteristics of a jet pump? Jet pumps are characterized by their simple and compact design, as well as the absence of moving parts; however, they have low mechanical efficiency and high steam consumption, which is why they are not used for general transportation purposes. Yet they are cost-effective when generating high vacuum levels. 31. What is the function of the quench water filter V1204? Chill water filter chamber V1204 is used to remove larger contaminants from the chill water, thereby preventing large particles from clogging the openings inside the chill ring. When the pressure difference across it is large, switching should be carried out promptly. 32. What is the function of the startup seal tank V1205? The start-up seal tank V1205 is used to vaporize the quenching liquid during preheating of the furnace; it maintains a suitable preheating liquid level intentionally, and is equipped with a movable baffle that can be used to adjust the liquid level within a certain range. 33. What is the working principle of the accident burner cooling water tank V1203? The accident burner cooling water tank V1203 is a liquid lift device; it uses low-pressure nitrogen N3 to increase the pressure at the liquid level in the tank, thereby pumping the liquid (i.e., the burner cooling water) into the burner circulation pipeline in emergency situations. 34. What is the structure of the preheating burner? The preheating burner is mainly composed of a central tube, a guide sleeve, a flower disc, a furnace lid, and brackets. 35. What is the working principle of a deaerator? That is, the graywater deoxygenation tank. The solubility of oxygen in water decreases as the water temperature rises; by exchanging heat between steam (or flash steam) and the water, the temperature rises and oxygen is effectively removed from the water. At the same time, the water temperature is controlled by regulating the gas phase pressure, thereby achieving the desired operational objectives. 36. What is the structure of deaerator V1302? The deaerator V1302 mainly consists of: a tank body, support plates, packing, heating chambers, etc. 37. What is the nominal diameter of a pipe? What is the nominal diameter of a container? The nominal diameter of a pipe is also known as its nominal bore; it is neither the inner diameter nor the outer diameter of the pipe, but rather an integer value that is close to its inner diameter. The nominal diameter of a pressure vessel refers to its inner diameter. 38. What is an automatic detection system? A system that uses various measuring instruments to measure, indicate, or record the main process parameters is called an automatic monitoring system. 39. What is an automatic control system? A system that automatically performs certain periodic operations on production equipment according to pre-defined steps. 40. What is an automatic control system? What is its composition? A system designed to automatically adjust certain key parameters in production, so that when they deviate from their normal values due to external disturbances, they can be automatically brought back within the specified range; such a system is known as an automatic control system. Its components are: the process variable, the sensing element, the transmitter, the automatic regulator, and the actuator. 41. Into which categories are self-regulating systems divided? It is divided into a fixed-value control system, a follow-up control system, and a degree control system. 42. What are fluid transport machinery? When fluid is in flow, it is sometimes necessary to supply a certain amount of external mechanical energy to the fluid. Fluid transfer machinery is the device that applies external energy to fluid machinery. A machine that transports liquids is usually called a pump. 43. Into which categories are pumps generally divided? Based on their working principle, pumps are generally classified into the following categories: (1) Dynamic type (impeller type), such as centrifugal pumps and shaft flow pumps. ⑵ Positive-displacement types, such as reciprocating pumps and gear pumps. ⑶ Other types, such as jet pumps. 44. Into which categories can centrifugal pumps be divided according to their purpose of use? Centrifugal pumps can be classified according to their purpose of use into: clean water pumps, oil pumps, corrosion-resistant pumps, impurity pumps, slurry pumps, metering pumps, etc. 45. What types can centrifugal pumps be classified into based on their structural design? ⑴ Suction impeller: single-suction, double-suction. ⑵ Number of stages: single-stage, multi-stage. ⑶ Pump body type: volute type, cylinder type. ⑷ Installation method: horizontal, vertical, inclined. 46. What are the main advantages and disadvantages of centrifugal pumps? The advantages of centrifugal pumps are: simple and compact structure, the ability to be connected directly to the motor, low requirements for installation, uniform flow that is easy to regulate, and low cost. The disadvantages of centrifugal pumps are: their head is generally not very high, their efficiency is low, they lack self-priming capability, and the viscosity of the fluid to be transported cannot be too high. 47. What are the main components of a centrifugal pump? A centrifugal pump is mainly composed of a pump body, pump cover, impeller, shaft, sealing components, bearing components, etc. 48. What is the working principle of a centrifugal pump? Before operating a centrifugal pump, it is first necessary to fill the pump with the medium to be transported. When a centrifugal pump is in operation, the impeller is driven by the motor to rotate at high speeds (1000–3000 rpm), forcing the fluid between the blades to rotate at an almost constant angular velocity. At the same time, due to the effect of centrifugal force, the fluid moves radially outward from the impeller. As the fluid flows through the impeller, it gains energy and exits the edge of the impeller at high speed to enter the volute. In the volute, the fluid slows down as the flow channel widens; its kinetic energy is converted into potential energy, and it then flows tangentially into the discharge pipe. At the center of the impeller, the fluid is forced to flow from the center toward the outer edge, resulting in a low pressure at the center. As a result of the pressure at the inlet, fluid is continuously drawn into the impeller. 49. What are the performance parameters of centrifugal pumps? The main performance parameters of a centrifugal pump include flow rate, head, power and efficiency, as well as rotational speed. 50. What is the theoretical head of a centrifugal pump? The theoretical head of a centrifugal pump is the maximum head that the pump can achieve under ideal conditions; it is usually expressed as the height of a liquid column of the medium being transported. The ideal condition is: (1) an infinite number of leaves with negligible thickness. ⑵ Steady state when in motion. ⑶ A liquid is ideally frictionless. 51. What is the actual head of a centrifugal pump? The actual head of a centrifugal pump is the head that the pump can actually achieve, taking into account volume losses, hydraulic losses, and mechanical losses. 52. What are the different types of impellers for centrifugal pumps? The impellers of centrifugal pumps are divided into covered, semi-covered, and open types. Open and semi-shielded impellers are suitable for transporting materials containing solid particles and those prone to scaling, but their efficiency is lower. Shielded impellers are used for transporting relatively clean materials, and they offer high efficiency. 53. What is the characteristic curve of a centrifugal pump? The head, efficiency, and shaft power of a centrifugal pump are all related to the flow rate; the curve showing these relationships is known as the pump’s characteristic curve, among which the relationship between head and flow rate is the most important. 54. What are the common methods for adjusting the flow rate of centrifugal pumps? The main methods of adjusting centrifugal pumps are: (1) Changing the characteristic curve of the pipeline, that is, altering the value of the resistance coefficient by adjusting the opening degree of the valves in the pipeline. This method is easy to use, but it results in low pump efficiency. ⑵ Changing the pump’s performance curve, such as by turning the impeller, or altering the pump’s speed – this method yields good pump efficiency, but it is not convenient to use; it is suitable for situations where the flow rate needs to be changed over a long period of time. 55. Why must the outlet be completely closed before starting a centrifugal pump? According to the pump’s characteristic curve, when the flow rate is zero, the starting power is at its minimum, which helps to effectively protect the motor; simultaneously, closing the outlet completely prevents hydraulic shock in the outlet pipeline. 56. What is cavitation? When the pressure at the inlet of the impeller drops to the saturated vapor pressure of the liquid being transported, it causes partial vaporization of the liquid. Vaporization occurs at the inlet of the impeller; when liquid containing bubbles enters the impeller, the increase in pressure causes the bubbles to disappear, creating a local vacuum. The surrounding liquid then rushes into the center of these bubbles at high speed, resulting in shock waves and vibrations. Especially when bubble coalescence occurs near the impeller surface, numerous liquid particles act like small, high-frequency water hammers striking the blades. At the same time, the bubbles may contain gases such as oxygen, which can cause chemical corrosion of metal materials; operation of the pump under such conditions can lead to premature damage of the impeller, a phenomenon known as pump cavitation. 57. What are the phenomena of cavitation? The outlet pressure of the pump drops, the head decreases, the flow rate reduces, and there is abnormal noise and vibration. 58. What are the hazards of cavitation? The hazards of cavitation include: (1) a sudden decline in pump performance. ⑵ The pump generates vibration and noise. ⑶ It causes chemical corrosion and mechanical damage to the pump’s flow-through components. 59. What is vapor entrapment? The head of a centrifugal pump is expressed as the height of the liquid column being transported. At the same head, the pressure difference between the inlet and outlet of the pump is proportional to the density of the liquid. When gas is present inside the pump, the average density of the liquid decreases, resulting in a reduced pressure difference or a very low vacuum level at the pump’s suction inlet, which prevents the liquid from being drawn into the pump. This phenomenon is known as vapor lock. 60. Why is it necessary to fill the pump before starting a centrifugal pump? If the pump casing of a centrifugal pump is filled with air, vapor locking will occur due to the low density of air, and the pump may be unable to draw in liquid. Therefore, it is necessary to fill the pump with liquid before starting it; this process is known as priming the pump. 61. What are the components of a packing seal? A packing seal is mainly composed of a packing retainer, packing, a liquid seal ring, a gland, gland bolts, and other components. 62. What are the advantages and disadvantages of packing seals? The advantages of packing seals are: easy installation, simple replacement, and low cost. The disadvantages of packing seals are: short service life, poor sealing performance, high frictional resistance, and they are not suitable for high-pressure applications or situations where low leakage levels are required. 63. What should be noted when installing a packing seal? Generally, newly installed packing should not be compressed too tightly; excessive compression leads to high friction, and the packing loses its elasticity, making it impossible to adjust. The tightness should be such that the leakage rate is 10 drops per minute. 64. What are the components of a mechanical seal? A mechanical seal is also known as a face-contact seal. It is mainly composed of a spring seat, fixing screws, a compression spring, a moving ring, a stationary ring, a square brick, a sealing ring, etc. 65. What are the characteristics of mechanical seals? The feature of mechanical seals is that they transform the axial seal, which is prone to leakage, into a static seal and an end-face radial contact seal that are less likely to leak. 66. What are the advantages and disadvantages of mechanical seals? The advantages of mechanical seals are: (1) low leakage rate (generally 1% of that of packing seals). ⑵ Long service life (1–2 years). ⑶ Frictional power consumption is low (10–50% of that of a packing seal). ⑷ The requirements for shaft machining accuracy have been reduced. The disadvantages of mechanical seals are high cost and high installation requirements. 67. What is the function of the sealing fluid in a mechanical seal? The sealing fluid for mechanical seals can be the medium itself, or it can be introduced from the outside at a pressure 0.05–0.15 MPa higher than that of the medium, in order to serve as a lubricant and coolant. 68. Under what circumstances should the sealing fluid for unloading the seal be introduced from the outside? When the sealed medium has poor viscosity, a high solid content, is corrosive, toxic, or similar, the sealing fluid for the mechanical seal should be supplied from the outside. 69. Which centrifugal pumps in this system draw in seal water from the outside? 70. What are the reasons why a centrifugal pump cannot achieve high flow rates? The reasons why a centrifugal pump cannot achieve high flow rates are: (1) Blockage or leakage in the pump’s inlet pipeline. ⑵ The inlet pressure of the pump is too low. ⑶ The opening of the pump inlet valve is too small, or the valve core has fallen off. ⑷ There is air in the pump. ⑸ Mechanical failure of the pump itself. ⑹ The pump outlet valve core has fallen off. ⑺ The grid voltage is low. 71. What precautions should be taken when a centrifugal pump is in operation? ⑴ Regularly check the readings of the pressure gauge and ammeter; if any abnormalities are detected, identify the cause and address it promptly. ⑵ Regularly monitor lubrication parameters, check the oil quality periodically, and replace it in a timely manner. ⑶ Regularly check the supply of lubricating oil, oil seals, as well as cooling water and sealing water. ⑷ Regularly check the tightness of the anchor bolts for centrifugal pumps and electric motors, as well as the temperature of the bearings in the pump and motor units and the sound emitted during pump operation; address any issues that are detected promptly. 72. Which centrifugal pumps are used in this system? ⑴ P1003 Grinding water pump ⑵ P1004 Additive underground tank pump ⑶ P1201 Nozzle cooling water pump ⑷ P1202 Hopper circulation pump ⑸ P1301 Quenching water pump ⑹ P1302 Condensate booster pump ⑺ P1303 High-pressure ash water pump ⑻ P1306 Auxiliary quenching water pump ⑼ P1307 Low-pressure ash water pump ⑽ P1401 Sludge tank pump ⑾ P1402 Slurry pump 73. What precautions should be taken before starting a centrifugal pump? ⑴ Search and inspection. ⑵ Check whether the pressure gauges for seal water and cooling water are functioning properly. ⑶ Check the electrical insulation. ⑷ Vent the filling pump. 74. What is the working principle of a metering pump? The metering pump commonly used in chemical production is a type of reciprocating pump. Its flow rate can be expressed as: Q = Fsn = n/4Dsn, where Q represents the flow rate, F is the area of the plunger, D is the diameter of the plunger, S is the stroke of the plunger, and n is the rotational speed. Since the flow rate is proportional to the stroke, it is also known as a proportional pump. By adjusting the mechanism that controls the plunger’s stroke, it is possible to precisely regulate the flow rate. 75. What are the operating characteristics of a metering pump? A metering pump can control the flow rate of the fluid being transported with great accuracy, is easy to adjust, and can sometimes meet the requirement of transporting two or more liquids in a precise flow ratio. They are mostly low-flow pumps. 76. What metering pumps are available in this system? The metering pumps in this system include: P1002 for additives, P1313 for coagulants, and P1314 for dispersants. 77. What is the working principle of gear pumps? Inside the gear pump casing, there is a pair of intermeshing gears; these pumps come in two types: internal meshing and external meshing. They divide the space inside the pump into a suction chamber and a discharge chamber that are not connected to each other. When the motor drives the gears to rotate, the liquid trapped between the tooth pockets and the pump casing is forced out. When the gears disengage, a vacuum is created which draws in liquid, and the discharge chamber generates the pressure required by the pipeline. 78. What are the characteristics of gear pumps? Gear pumps are easy to manufacture, reliable in operation, and have self-priming capability. However, their flow rate and pressure can fluctuate, and they generate noise and vibration. Gear pumps have a low flow rate but are capable of producing high head pressures; they can also transport viscous liquids such as lubricants. However, it is not suitable for transporting suspensions containing solid particles. 79. What is the working principle of a water ring vacuum pump? In a water-ring vacuum pump, the impeller is mounted eccentrically within the pump body. Before starting, a certain amount of water is poured into the pump. As the impeller rotates, the water is subjected to centrifugal force, resulting in the formation of a rotating water ring against the walls of the pump body. The blades and the distributors at both ends create a sealed cavity. During rotation (as air passes through the suction port), the volume of this sealed cavity gradually increases, and gas is drawn in through the suction port ； During the rotation in the latter half of the turn (at this point passing through the exhaust port), the volume of the sealing cavity gradually decreases, and gas is discharged through the exhaust port. To maintain a constant water ring, water must be continuously supplied to the pump during operation. 80. What is the structure of a water ring vacuum pump? 81. What are the characteristics of water ring vacuum pumps? The water ring vacuum pump belongs to the category of wet vacuum pumps; it allows liquid to be included in the intake air, has a simple and compact structure, and can achieve a maximum vacuum level of 85%. The water ring vacuum pump can also be used as a blower, with an outlet pressure not exceeding 1 atm (gauge pressure). 82. What is the purpose of filling water into a water ring vacuum pump? Filling a water ring vacuum pump with water is primarily done to maintain the liquid seal inside the pump while it is in operation, and it also serves a cooling purpose. 83. Into which categories are heat exchange equipment generally divided? Heat exchangers can be classified into the following three categories based on their heat transfer characteristics: (1) Direct contact type (mixed type) ； ⑵ Regenerative ； ⑶ Partition type. Among them, the partitioned heat exchangers are the most widely used type of heat exchanger in industry. 84. Into which categories are partition-type heat exchangers generally divided? Partition-type heat exchangers can generally be classified according to the shape of their heat transfer surfaces as follows: (1) Tubular types: such as sleeve type, shell-and-tube type, spiral-plate type, and heat-pipe type. ⑵ Plate-type: such as plate type, spiral plate type, and plate-shell type. ⑶ Extended surface types: such as plate-fin type, tube-fin type, and enhanced heat transfer tube type. 85. How many types are there for shell-and-tube heat exchangers? Shell-and-tube heat exchangers, also known as tube-in-shell heat exchangers, are the most widely used type of heat exchanger in industry today, with mature technology. Tube heat exchangers can be classified according to the presence or absence of thermal compensation, as well as the type of thermal compensation, into: (1) fixed tube sheet type ； ⑵ floating head type ； ⑶ U-tube type. 86. What are the main components of a tubular heat exchanger? A shell-and-tube heat exchanger is mainly composed of components such as a shell, tube bundle, tube sheet, and end caps. 87. What is a tube side, and what is a shell side? Each time fluid passes through the tube bundle in a pipe is called one tube pass. Each time the fluid passes through the shell is called one shell cycle. 88. Why are baffle plates installed in shell-and-tube heat exchangers? The purpose of installing baffle plates is to increase the heat transfer coefficient outside the tubes, improve heat exchange efficiency, and also serve to support the tube bundle. 89. What are the reasons for fouling on the heat transfer surfaces of heat exchangers? The main reasons for fouling of the heat transfer surface are: (1) Fluids containing impurities entering the heat exchanger. ⑵ Condenses or crystallizes due to the decrease in fluid temperature. ⑶ When a liquid is heated, the substances dissolved in it precipitate out, such as the compounds of calcium and magnesium contained in water. ⑷ Corrosion products formed as a result of the fluid’s corrosive effect on the vessel walls. 90. What are the characteristics of fixed-tube-sheet heat exchangers? The fixed tube sheet design features tube sheets at both ends that form an integrated structure with the shell, and it is suitable for applications where the temperature difference between the hot and cold fluids is not large. This type of heat exchanger has a low cost and a simple structure, but the shell side is difficult to clean; therefore, the fluid flowing outside the tubes must be pure and resistant to scaling. When the temperature difference is large but the pressure inside the shell is not high, expansion joints can be installed on the shell wall to reduce thermal stress. 91. What are the characteristics of floating-head heat exchangers? In a floating-head heat exchanger, one of the tube sheets at each end can float freely along the axial direction. This design not only eliminates thermal stresses entirely but also allows the entire tube bundle to be removed from the shell, facilitating cleaning and maintenance. However, it is a more complex structure with higher costs. 92. What are the characteristics of U-tube heat exchangers? In a U-tube heat exchanger, each heat transfer tube is bent into a U shape; the inlet and outlet are located on opposite sides of the same tube sheet. The end caps are divided into two chambers by partitions. Each tube can expand and contract freely, independent of the outer shell. However, it is difficult to clean the inside of the tubes, so such exchangers are used only with fluids that are clean and do not tend to form scale. 93. What are the characteristics of immersive coil heat exchangers? An immersive coiled tube heat exchanger bends metal tubes into a shape suitable for the container and immerses them in the liquid inside the container; its advantages are a simple structure and the ability to withstand high pressures. Its disadvantage is the low fluid flow rate inside the container and a small heat transfer coefficient outside the tubes; to increase the heat transfer coefficient outside the tubes, a stirrer can be installed inside the container. 94. What is the function of an expansion joint? In fixed-tube-sheet heat exchangers, when there is a large temperature difference between the tube wall and the shell wall, significant axial forces are generated within the tube sheet. A U-shaped expansion joint is a flexible component, and therefore it can effectively compensate for axial deformation. This helps to reduce the axial forces on the pipes and the housing, thereby preventing damage to the equipment. 95. What are the types of expansion joints? The common types of expansion joints are U-type, flat plate type, and Ω-type. When a larger amount of compensation is required, multi-waveform expansion joints can also be used. 96. Which fluids are suitable for the tube side? ⑴ Unclean and scale-prone fluids should be routed in the tube side, as cleaning inside the tubes is easier. ⑵ Corrosive media should be routed in the tube side to prevent simultaneous corrosion of the tube bundle and the shell. ⑶ Fluids with high pressure should flow inside the pipes to prevent the housing from being subjected to high pressure. ⑷ Fluids that require an increased flow rate to raise their convective heat transfer coefficient should flow inside the tubes. 97. Which fluids are suitable for the shell side? ⑴ Saturated steam should flow in the shell side, as it is relatively clean, its heat transfer coefficient is independent of flow velocity, and the condensate can be easily removed. ⑵ The cooled fluid should flow through the shell side to facilitate heat dissipation. ⑶ If the temperature difference between the hot and cold fluid streams is large, for heat exchangers with rigid structures, it is advisable to pass the fluid with a higher heat transfer coefficient through the shell side in order to reduce thermal stress. ⑷ Fluids with high viscosity are generally better suited for use in the shell side, as a turbulent flow can be achieved when the Reynolds number Re on the shell side is greater than 100. 98. What are the precautions to take when operating a tubular heat exchanger? ⑴ When adjusting the heat exchanger, temperature, pressure, and flow rate should not fluctuate too much; otherwise, not only will the heat transfer efficiency decline, but it will also affect the equipment’s service life and may even cause damage. ⑵ During regular operation, pay close attention to changes in the pressure, temperature, and flow rate at the inlet and outlet of the heat exchanger; if any changes occur, identify the cause and address it promptly. ⑶ For condensers, it is necessary to pay regular attention to the discharge of non-condensable gases. ⑷ For heat exchangers installed outdoors, the fluid inside them must be drained during winter shutdown to prevent freezing and damage to the heat exchanger. 99. Into which two main categories are temperature measuring instruments divided based on their measurement method? Based on the measurement method, they are divided into two main categories: contact and non-contact. 100. What are the categories of contact-type temperature measuring instruments? They are divided into four categories: expansion type, pressure type, thermocouple, and thermal resistor. 101. Into which categories are contactless temperature measuring instruments divided? Non-contact temperature measuring instruments are divided into two main categories: radiant type and infrared type. 102. What are the common types of thermocouples? Common types of thermocouples include: (1) Platinirhodium 30–Platinirhodium 6 thermocouple (B); (2) Platinirhodium 10–Platinirhodium thermocouple (S); (3) Nickel-chromium–Nickel-silicon (Nickel-chromium–Nickel-aluminum) thermocouple (K); (4) Nickel-chromium–Copper thermocouple (XK). 103. What components does a thermocouple consist of? It consists of five parts: the hot end, heat electrode, insulating tube, protective sleeve, and junction box. 104. What are the requirements for installing temperature sensing elements? ⑴ Insert it in the pipe in counterflow or co-current direction. ⑵ The temperature sensing point should be located at the area with the highest flow velocity in the pipeline. ⑶ There should be sufficient insertion depth. ⑷ If the process pipe diameter is small, an expansion pipe needs to be installed. ⑸ The face of the junction box should face upward. ⑹ It should be inserted at the location of the pipe or equipment within the right insulation layer. ⑺ In the negative-pressure tube, its sealing performance must be ensured. 105. What is a thermocouple thermometer? A thermocouple thermometer is a temperature measuring instrument based on the thermoelectric effect. 106. What is the principle of temperature measurement in thermocouple thermometers? The temperature measurement principle of thermocouple thermometers is based on the thermoelectric effect of thermocouples. The potential difference generated by a thermocouple changes as the temperature being measured changes; therefore, a thermocouple can be used as a temperature sensing element. 107. What is a thermistor thermometer? A thermistor thermometer is a thermometer that uses a thermistor as the temperature-sensing element. 108. What is the principle of temperature measurement in a thermistor thermometer? Thermistor thermometers utilize the property that the resistance value of metal conductors changes with temperature to measure temperature. 109. What material are the high-temperature and preheating thermocouples in the gasifier? What is the temperature measurement range? The material of the high-temperature thermocouple is platinum-rhodium 10-platinum-rhodium, with a temperature measurement range of 0～1700°C; the material of the preheating thermocouple is nickel-chromium-nickel-silicon, with a temperature measurement range of 0～1000°C. 110. What is traffic? What are the different ways of expressing it? What is the relationship between them? Flow rate refers to the amount of fluid that passes through a cross-section of a pipe per unit of time, and it is divided into volume flow rate and mass flow rate. Mass flow rate = Volume flow rate × Fluid density. 111. What are the components used to measure flow rate? Elements used to measure flow rate include: orifice plates, nozzles, Venturi meters, rotors, electrically transmitted rotors, epicyclic gears, turbines, and electromagnets. 112. How many types of standard throttling devices are used in this device? What are their respective characteristics? There are two types: orifice plates and venturis. The pressure loss of orifice plates is high, while that of Venturi tubes is low. For the same differential pressure, the pressure loss of an orifice plate is 3 to 5 times greater than that of a Venturi tube. When the pipe diameter and differential pressure are the same, the Venturi tube has a higher flow coefficient and thus a larger flow rate, making it suitable for measuring fluid flow rates in large-diameter pipes. 113. What are the various methods for taking pressure readings at a throttle orifice plate? There are: corner tapping method, flange tapping method, theoretical tapping method, chord distance tapping method, and pipe connection tapping method. Various pressure-taking methods are commonly used here. 114. What are the basic components of a differential pressure flow meter? What is its measurement principle? A differential pressure flow meter consists of a throttling device and a differential pressure gauge. The function of the throttling device is to convert the flow rate being measured into a differential pressure signal ； The function of a differential pressure gauge is to convert the differential pressure signal into the corresponding flow rate value. A differential pressure flow meter is based on the throttling principle of fluid flow; it measures flow rate by utilizing the pressure difference that occurs when fluid passes through a throttling device. 115. What factors affect the measurement of differential pressure flow meters? ⑴ Changes in the operating conditions of the fluid under test ； ⑵ The throttle device is not installed correctly ； ⑶ Wear at the edge of the orifice plate opening ； ⑷ The pressure guide tube is installed incorrectly, or there are blockages or leaks ； ⑸ The differential pressure gauge is installed or used incorrectly. 116. What is the measurement principle of a rotameter? A rotameter is a flow meter with a constant pressure difference. Flow rate is measured based on the rising height of the rotor inside the conical tube; it utilizes the pressure difference generated as fluid passes through the gap between the rotor and the tube wall to balance the weight of the rotor. The greater the flow rate, the higher the rotor is lifted; the larger the cross-sectional area of the flow channel, but the pressure difference remains unchanged. 117. What is the measurement principle of electromagnetic flowmeters? The principle involves using a conductive liquid that, when passing through a magnetic field, cuts through the magnetic field lines to generate an induced electromotive force. Choosing the appropriate electrode material makes it suitable for high temperatures and highly corrosive environments with suspensions as the medium, and it also features low pressure loss. 118. Why is the orifice plate installed in front of the control valve? In the theoretical basis for measuring flow rate using throttling devices, there are two assumptions: that the fluid flow is continuous, and that the law of conservation of energy applies during the flow process. This tells us that orifice plates should not be installed in areas where gas and liquid coexist, as this could increase measurement errors. Some liquids may partially vaporize after passing through a control valve, resulting in a two-phase mixture; therefore, the orifice plate for measuring flow rate should be installed as close as possible to the control valve. 119. How should a rotameter be installed? Where is it mainly used? Rotary flow meters should be installed vertically and are primarily used for measuring low flow rates. 120. What are the differences in the functions of electromagnetic flowmeters, venturi flowmeters, and orifice plate flowmeters? Electromagnetic flowmeters are suitable for solutions containing oleic acid, alkalis, and salts, as well as fluids with solid particles or fibers ； Venturi flowmeters are suitable for fluids containing a small amount of solid particles ； Orifice plate flow meters are suitable for clean fluids free of solid particles. 121. Where are the electromagnetic flowmeters used in this system? The locations in this system where electromagnetic flowmeters are used are: slurry flowmeters (FIA1202, FQIA1203) 122. Where are the Venturi flowmeters used in this system? The places in this system where venturi flow meters are used include: oxygen flow meter (FICA1205) ； Quench chamber black water discharge flow meter (FICA1212) ； Flow meter for gray water in T1301 (FICA1304) ； Black water discharge flow meter at the bottom of the carbon scrubber tower (FICA1305) ； Venturi scrubber water supply flow meter (FICA1306) ； Accident Quench Water Flow Meter (FICA1307) ； Quench water flow meter (FICA1308). 123. What is liquid level? What is material level? The height of the liquid medium in a container is called the liquid level ； The height of the accumulation of solid or granular materials in a container is called the material level. 124. Into which categories can level gauges be divided based on their working principle? They can be divided into seven major categories: direct-reading type, differential pressure type, buoyancy type, electromagnetic type, nuclear radiation type, acoustic wave type, and optical type. 125. What is the principle of operation of a differential pressure level gauge? What is the principle of buoyancy-based level measurement? The differential pressure type operates on the principle that the liquid level or the accumulation of material creates pressure at a specific point ； The buoyant type operates on the principle that the height of the float changes as the liquid level changes, or that the buoyancy of the submerged cylinder changes with the liquid level. 126. What is the principle of measurement for electromagnetic level gauges? The principle of electromagnetic level measurement is to convert changes in liquid level into changes in electrical quantities, and by detecting these electrical changes, the liquid level can be determined ； The principle of nuclear radiation-based level measurement relies on the fact that the intensity of nuclear radiation as it passes through a material changes depending on the thickness of that material layer. 127. What are the components of an electromagnetic flap-type level gauge? An electromagnetic flap level gauge mainly consists of the gauge body, a float with an internal directional magnetic source, and a flap box, among other components. 128. What is the working principle of an electromagnetic flap level gauge? The principle is as follows: The float inside the level gauge floats on the surface of the liquid medium. As the liquid level within the gauge changes in sync with the level in the container, the float floating on top also changes accordingly. Under the magnetic influence of a directional magnetic source, the flaps on the flap box change direction, and the colors of these flaps indicate different levels. The change in the color of the flip plate interface depends solely on the position of the float, unaffected by the medium pressure, making it suitable for on-site level measurement. 129. Into which major categories are pressure measuring instruments classified according to their conversion principle? What is its measurement principle? Pressure measuring instruments can be roughly divided into four categories: (1) Manometric pressure gauges, which utilize the principles of hydrostatics to convert the measured pressure into a height of a liquid column for measurement. ⑵ An elastic pressure gauge converts the pressure to be measured into a deformation displacement of an elastic element for measurement. ⑶ An electrical pressure gauge is a measuring instrument that converts the pressure to be measured into an electrical signal using mechanical and electrical components. ⑷ A piston pressure gauge operates on the principle of fluid pressure in hydraulic presses; it converts the pressure to be measured into the mass of the weight applied to the piston for measurement purposes. 130. How many categories can common pneumatic pressure transmitters be divided into? They are divided into two categories: one is the pressure transmitter constructed based on the principle of force balance ； Another type is the pressure transmitter constructed based on the principle of force balance. 131. What are the pressure-sensing elastic elements of elastic pressure gauges? There are elastic elements such as bellows, corrugated tubes, and diaphragms. 132. What are the measuring elements of an electrical pressure gauge? There are components such as capacitors, resistors, inductors, strain gauges, Hall effect sensors, etc. 133. What are the components of an electric contact pressure gauge? A electric contact pressure gauge consists of: static contacts, moving contacts, an indicator light, and the pressure gauge body. 134. What is the working principle of an electric contact pressure gauge? An electric contact pressure gauge uses a moving contact to indicate the measured pressure, while a stationary contact indicates the set value. When the measured pressure (moving contact) comes into contact with the set value (stationary contact), it activates the air supply, generates a corresponding alarm signal, or triggers an appropriate interlock action. 135. What is the measurement principle of a liquid column manometer? Which ones are commonly used? Its working principle is based on the principles of hydrostatics, and it is used to measure low negative pressures or pressure differences of less than 200 kPa. The commonly used types are U-tube type, single-tube type, and inclined-tube type. 136. Based on the energy source used by the instrument, into which two main categories can instruments be divided? It can be divided into: (1) Direct-acting regulators (self-acting regulators) ； ⑵ Indirect action regulators are classified into electric regulators, pneumatic regulators, and level regulators, depending on the external power source used. 137. What are the two components of a pneumatic diaphragm control valve? A pneumatic diaphragm control valve consists of two parts: the actuator (diaphragm head) and the control mechanism (valve body). The actuator is used to generate power, while the control mechanism is used to regulate the flow rate of the medium. 138. What are the characteristics of pneumatic diaphragm actuators? Pneumatic diaphragm actuators generate thrust through a corrugated diaphragm; they feature reliable operation, easy maintenance, and low cost. It is the most widely used actuator. Such actuators typically receive a standard signal pressure of 20–100 kPa; with a positioner, the maximum pressure can reach 250 kPa. They are available in both direct-acting and reverse-acting versions. 139. What are the main types of pneumatic diaphragm control valves? The main types include: straight-through single-seat valves, straight-through double-seat valves, as well as angle valves, diaphragm valves, three-way valves, butterfly valves, eccentric rotary valves, and others. 140. What are the characteristics of pneumatic piston actuators (cylinder type)? What are the two forms? The air supply pressure for this actuator can reach 500 kPa, and the spring counteracts the pushing force, resulting in high output force. It is used in large-diameter valves with high static pressure and high pressure differences, as well as butterfly valves. Pneumatic piston actuators are available in proportional and on-off types. 141. What are the characteristics of a straight-through single-seat valve? A straight-through single-seat valve has only one valve element and one seat inside its body. Its main characteristics are low leakage, a low allowable pressure difference, and low flow capacity. This type of valve is suitable for applications where low leakage and a small pressure difference are required (when the pressure difference is high, an actuator with high driving force or a valve positioner must be used). 142. What are the characteristics of a straight-through two-seat valve? The body of the direct-through two-seat valve contains two spools and valve seats. When the valve is closed, the leakage rate is high; it is suitable for applications with large pressure differences and complex flow paths, but not suitable for liquids with high viscosity or containing solid particles. 143. What are the characteristics of angle-type control valves? The body of the corner-type control valve is at a right angle, featuring a simple flow path, low resistance, and minimal tendency to clog; it is suitable for regulating fluids with high pressure differences, high viscosity, as well as those containing suspended solids and particles. 144. What are the characteristics of butterfly valves? What occasions is it suitable for? Butterfly valves, also known as flap valves, have a high flow capacity, are inexpensive, exhibit low pressure loss, do not easily accumulate deposits, have a compact structure that requires little installation space. However, they require significant operating torque and have low leakage rates. Adjustable butterfly valves have a limited application range; they are particularly suitable for gases and slurry-like liquids with low pressure differences, large diameters, and high flow rates. 145. What are the characteristics of O-type valves? Type O valves can be used for regulation and shut-off; they are commonly controlled in a two-position manner and are known as on/off ball valves. The valve element is spherical with a cylindrical through-hole. Its main advantage is a simple flow path – when fully open, it creates a straight tube-like passage, resulting in minimal pressure loss. It is particularly suitable for fluids with high viscosity, suspensions, pulp, etc., offering reliable sealing and low leakage. 146. What are the characteristics of self-acting control valves? A self-acting control valve, also known as a directly acting control valve, is a type of control valve that does not require any external power source. It integrates the functions of sensing, control, and actuation into one unit, utilizing the energy from the process itself to drive its operation. It is suitable for situations where there are small variations in flow rate, where high precision in control is not required, or where it is difficult to obtain a supply of instrument air. 147. How can self-acting control valves be classified according to their uses? Based on their function, they can be classified into pressure control valves, differential pressure control valves, level control valves, temperature control valves, and flow control valves. 148. What is the function of the packing in a control valve? The packing of the control valve is installed in the packing chamber of the valve cover; its function is to prevent the medium from leaking outward due to the movement of the valve stem. The common types of packing include \"V\"-shaped polytetrafluoroethylene packing and \"O\"-shaped graphite packing. 149. What is the Adjustable range of a control valve? What does it depend on? The ratio of the maximum flow rate to the minimum flow rate that a control valve can regulate is known as the regulation ratio of the control valve. Based on whether the pressure difference across the valve changes, it is further divided into ideal adjustability and actual adjustability; the ideal adjustability depends on the structure of the valve core and the conditions of the piping. 150. What are the ideal flow characteristics of control valves? The ideal flow characteristics include four types: linear, equal percentage, quick opening, and parabolic. 151. What is the flow characteristic of a control valve? The relationship between the relative flow rate of the medium passing through the valve (Q/Qmax) and the relative stroke of the valve (l/L) is known as the flow characteristic of the control valve. 152. What are the ideal flow characteristic and operating flow characteristic of a control valve? Assuming that the pressure difference before and after the valve remains constant, the flow characteristic of the control valve is referred to as the ideal flow characteristic; it depends solely on the shape of the valve element. In actual use, however, the pressure difference before and after the valve is always changing, and in such cases the flow characteristic of the control valve is called the operating flow characteristic, which depends on both the shape of the valve element and the conditions of the piping. 153. What are the flow-on and flow-off types of valves? Flow open and flow closed refer to the direction of flow of the medium; it is defined as follows: at the throttle, when the medium flows in the direction in which the valve is open (i.e., in the same direction as the valve’s open position), it is called flow open, while when it flows in the direction in which the valve is closed (i.e., in the same direction as the valve’s closed position), it is called flow closed. 154. How to choose between flow-open and flow-close types of valves? Both open-flow and closed-flow types have their advantages and disadvantages. Generally, valves of the open-flow type operate more stably, but they have poorer self-cleaning capabilities and sealing performance, as well as a shorter lifespan ； Valves of the flow-blocking type have a longer service life, good self-cleaning and sealing properties, but poor stability; the specific choice should be determined based on the operating conditions and the main challenges involved. 155. What are gas opening and gas closing? The operation mode in which the control valve closes when there is signal pressure and opens when there is no signal pressure is called air-shut, while the opposite mode is called air-open. Gas opening and gas closing are determined by the forward and reverse actions of the actuator and the forward and reverse installation of the valve body components. 156. What are the criteria for selecting the type of gas lock? Primarily from the perspective of production safety, it is necessary to determine what position the valve should be in when there is a fault with the gas supply signal and no gas pressure is available. 157. What are the auxiliary devices of pneumatic valves? There are valve positioners, pneumatic holding valves, tees, four-way solenoid valves, handwheel mechanisms, pneumatic relays, air filters and pressure reducers, air storage tanks, etc. 158. What valves are included in a control valve assembly? What is each of them used for? A control valve assembly generally consists of a front valve, a rear valve, a bypass valve, and a drain valve. The front and rear valves serve to shut off flow, and gate valves are usually selected for this purpose ； Bypass valves are used for initial operation; ball valves are generally chosen for this purpose. Drain valves are utilized for servicing control valves or for draining the fluid from pipes and valves during shutdowns, and they are also used to introduce external fluid to flush the interior of valves and pipes. 159. What is a control object? Given value and deviation? In an automatic control system, the production equipment whose process parameters need to be adjusted is called the controlled object. The process parameters that must be maintained during production are referred to as setpoints. In such systems, it is common to use the difference between the setpoint and the measured value as the deviation; when the setpoint is greater than the measured value, it is considered a positive deviation, while when the setpoint is less than the measured value, it is known as a negative deviation. 160. How is a simple control loop structured? It generally consists of a detection transmitter, a control object, a regulator, and an actuator. 161. How is a cascade control loop structured? A cascade control system consists of two sets of sensing transmitters, two sets of regulators, one control valve, and a primary and a secondary process. The entire system comprises two control loops: the primary loop and the secondary loop. The secondary loop is made up of a secondary variable sensing transmitter, a secondary regulator, the control valve, and the secondary process ； The main loop consists of the main variable detection transmitter, the main regulator, the equivalent elements of the secondary loop, and the main object. 162. What are the characteristics of a cascade control loop? A cascade control system belongs to a fixed-value control system; the output of the main regulator serves as the setpoint for the secondary regulator, and the output of the secondary regulator is sent to the control valve. The main regulator performs setpoint control, while the secondary regulator carries out follow-up control. Compared with single-loop control systems, cascade control loops have the following characteristics: (1) They have a relatively rapid and strong ability to overcome disturbances that enter the secondary loop; the introduction of the secondary loop **improves the quality of control. ⑵ It can improve object characteristics. ⑶ It can eliminate the influence of the nonlinear characteristics of the control valve. ⑷ It can take into account both primary and secondary variables. 163. What is automatic control? Automatic control refers to the process of controlling a manufacturing process without any human intervention. On-site measuring instruments such as temperature meters, KTD/TC devices, and transmitters are used to measure process variables like pressure, temperature, and flow rate. These measurements are then converted into standard signals that are sent to actuators, thereby controlling the process variables so that they reach the set values, until any deviations are eliminated. 164. What is a control loop? A circuit composed of the measuring elements, controller, and actuator in the measurement process is called a control loop. 165. What is DCS? DCS is the abbreviation for a centralized management, decentralized control system. 166. What is the concept of a distributed control system? A distributed control system is a new type of system that combines a microprocessor as the core component, data communication devices, CRT display units, and process input/output interfaces. It utilizes microprocessors and microcomputers to control various stages of a continuous production process, while all information is transmitted via a data communication bus made up of a coaxial cable. Optimization is achieved through monitoring by a central computer, with centralized management being possible at the monitoring station using image displays and keyboards. 167. What are the characteristics of DCS? The system has decentralized control functions, centralized monitoring operations, executable control logic, excellent human-machine interaction, simple installation and wiring, as well as simple and safe operation. 168. In what aspects do the advantages of distributed control systems lie? ⑴ The system is easy to operate, with good human-machine interaction ； ⑵ Flexible system expansion ； ⑶ High reliability ； ⑷ Save on cables and reduce material and installation costs ； ⑸ It has good compatibility. 169. What does redundancy in a system refer to? Redundancy refers to a configuration of multiple components, such that when one or several of these components fail to function properly, the remaining components can still produce the correct output, thereby ensuring the safety of the system. 170. What are some common terms used in automatic control systems? Controlled object: The device, machine, or production process that needs to be controlled is referred to as the controlled object. Controlled variable: A physical quantity within the controlled system that is required to maintain a set value (either close to a constant value or changing according to a predetermined pattern) is known as the controlled variable. Operating variable: A physical quantity or energy that is transmitted to the control device to be manipulated in order to maintain the controlled variable at a set value. 171. What are the two types of automatic control systems? There are two types: open-loop control systems and closed-loop control systems. 172. What components make up a closed-loop control loop? It consists of several components: detection, transmission, regulation, and actuation. 173. What are the types of closed-loop control systems? ⑴ Fixed-value control system ； ⑵ Follow-up control system ； ⑶ Programmable (sequential) control system. 174. What are the types of main control systems? The main types include cascade control systems, proportional control systems, ratio control systems, and range control systems. 175. What is feedback? The process of returning the output signal to the input after going through certain stages is called feedback. 176. What is the function of a transmitter? Its function is to convert the signals generated by the sensing elements into standard signals, which are then sent to display instruments or control devices for display, recording, or regulation. 177. What is a PLC? PLC is the abbreviation for Programmable Logic Controller; it is a sequential control device based on a microprocessor, and it consists of both hardware and software. 178. What are the characteristics of PLCs? The operation of a PLC requires human intervention; based on various input signals, logical control is carried out through logical operations and judgments, with the output acting on an execution unit. PLCs carry out sequential control through pre-programmed control routines, and feature flexibility, high speed, and high reliability. 179. What is an SP value? SP stands for setpoint, the predetermined value of the controlled variable. 180. What is an OP value? OP stands for output value, the signal that the controller sends to the actuator. 181. What is a PV value? PV refers to the measured value, which is the numerical value of the process variable as detected by the measuring element. 182. How to properly put a cascade control system into operation? First, use manual control to bring the primary parameter close to or equal to the set value while keeping the secondary parameter stable. Then switch the secondary regulator from manual to automatic mode. Once the secondary loop is in automatic mode, adjust the primary controller to bring the primary parameter close to or equal to the set value; once the adjustment of the secondary loop becomes stable, the primary regulator can also be switched to automatic mode. During operation, it is necessary to activate the secondary loop first and then the primary loop, ensuring a seamless transition with no disturbances. 183. How to standardize the manual-to-automatic switching process? The switch-over should be carried out without any disturbances. Before switching to automatic control, manual operation must be used first to keep the controlled variable stable at the set value. Only after the operating conditions have been stable for a certain period of time should automatic operation be engaged. During the switch-over process, it is necessary to maintain a constant pressure on the manual valve, meaning that the opening degree must remain unchanged; otherwise, artificial disturbances will occur. 184. What instruments are generally used for extinguishing fires in the instrument control room? Generally, 1211 fire extinguishers and carbon dioxide fire extinguishers are used. 185. What actions should be taken to extinguish a fire in the instrument control room? Step 1: Cut off the power supply ； Step 2: Cut off the power air supply ； In the third step, use a fire extinguisher or sand to put out the fire. VI. Diagnosis and Handling of Common Problems in the Conversion System 1. Excessive water in the water-gas mixture: The temperature of TICA1501 drops, while the level of LT1502 rises. Harm: If the separated water enters subsequent pipelines along with the syngas, it first reaches E1502, where it cools the tubes in this unit; this could lead to a disruption in the circulation of heat through those tubes. As the water moves further downstream, it enters the shift reactor, causing the temperature there to drop rapidly until it drops below the acceptable level. This results in the catalyst being damaged, the active components within it being lost, and the catalyst forming a crust on its surface, which increases resistance and leads to excessively high levels of CO at the outlet. Handling: When the liquid level is above the predetermined value, LV1502 will automatically open to allow discharge; this is done to inform the gasification unit and to stabilize the operation of the scrubber tower. When the liquid level reaches the high-level alarm value in separator V1501, close attention should be paid to TIC1501 and TCA1505. If the temperature drops rapidly, initiate an emergency shutdown. 2. Syngas peroxide phenomenon: The temperature of the converter bed rises significantly. Hazard: The presence of O2 in the syngas causes the temperature of the entire catalyst layer to rise sharply. Meanwhile, O2 reacts with MoS2, CoS, and H2S to form sulfate compounds, which can cause corrosion in subsequent equipment and pipelines. Handling: Once a sudden rise in the temperature of the converter bed layer is detected, the system immediately shuts down urgently, and PV1505 is opened appropriately to relieve pressure in the system. 3. Phenomenon of water carried in the generated steam: Alarm for high temperature in the waste boiler; water may emerge from the safety valve at the top of the waste boiler; there may be water hammer sounds in the external steam pipes. Harm: ① It reduces the quality of the steam produced, as ions such as Ca2+, Mg2+, and Cl1- present in the waste boiler water end up in the steam system. ② Water hammer in the outer pipe may cause circulation in the outer pipe and the valve. ③ When 0.5MPa steam contains water, it affects factors such as the temperature of the shift reactor. Solution: The control room instructed the site to immediately open the waste discharge valve in order to reduce the temperature to normal levels. 4. One vaporizer trips: The pressure and temperature of the syngas at the inlet section decrease, the hot spot temperature in the shift reactor rises, and the amount of steam generated by each waste heat boiler decreases. Hazard: The converter may overheat. Treatment: ① Increase the flow rate of TV1505; if this does not suffice, reduce the manual valve for syngas at the feed preheater (E1502). ② If the level of the waste pot rises, open the waste pot drain. Note: When the amount of syngas is reduced by half, the space velocity decreases, and the heat generated in the furnace cannot be removed in time, resulting in an increase in the bed temperature. 5. At the boiler feedwater side of the 1# low-pressure steam generator: The inlet temperature of the converter rises rapidly, and the level of the waste boiler liquid decreases. Harm: ① Increases the cooling requirements for E1502. ② An increase in the converter inlet temperature raises the bed temperature. ③ Due to the lack of water in the boiler caused by lung heat, it can quickly lead to an alarm indicating a low liquid level in the waste heat boiler, or even result in the boiler running dry. Treatment: Close the feed water valve of the intermediate waste heat boiler, and initiate an emergency shutdown of the system. 6. At the boiler feedwater side of the 2# low-pressure steam generator: The liquid level in the 2# low-pressure steam generator decreases, while the temperature of TI1511 rises sharply, and the temperature of TI1514 also increases. Harm: ① It may cause a low level alarm in #2 low-pressure steam generator or lead to drying out. ② Notify the dispatch team to pay attention to the gas temperature in the desulfurization tower, as well as the temperature of the solution at the bottom of the regeneration tower. ③ Increase the cooling water flow rate for cooler E1506, and increase the discharge from separator V1502 No. 2. ④ Decide whether to shut down based on the operation status of the waste heat boiler and desulfurization system. 7. Cut-off of instrument air: Alarm for low instrument air pressure; the individual control valves fail to function, with the FO valves opening fully, the FC valves closing fully, and the FL valves remaining in their original state; high level alarms are triggered for the liquid levels in #1 low-pressure steam generator E1501 and #2 low-pressure steam generator E1502. Hazard: Water is present in #1 low-pressure steam generator and #2 low-pressure steam generator, resulting in an increased water content in the desulfurization system. Handling: If it is found that the instrument air pressure is too low or the control valve is not functioning properly, the plant should be shut down for maintenance. 8. Low-voltage power failure: Level of 1# gas-liquid separator V1501 rises, liquid level in stripper T1501 increases, level of 3# gas-liquid separator V1503 rises, and P1501, P1502, and P1503 trip. Harm: ① An increase in the level of V1501 will cause water to enter the shift reactor R1501 via the raw gas preheater E1502. ② If the liquid level in stripper T1501 rises, it will prevent timely drainage of the water from separator V1502#2, leading to an increase in liquid level and the entry of water into the desulfurization system. Handling: Decide whether to shut down the machine based on the recovery of low-voltage power. 9. Desulfurization phenomenon of the shift catalyst: The catalyst’s activity decreases, the sulfur content at the outlet of the shifted gas is higher than that in the inlet syngas, and the catalyst exhibits sulfur release. Reason: ① The bed layer temperature is too high. ② The water-vapor ratio is too high. ③ The H2S content in the syngas is too low. Treatment: ① Maintain a lower bed temperature. ② Vaporization controls a lower water-to-vapor ratio. ③ To control an appropriate concentration of H2S in syngas, operational experience generally suggests that a level of not less than 1000 ppm is suitable. 10. Increase in the bed resistance PDT1503 of the converter: An increase in PDT1503 leads to a reduction in the amount of syngas fed into the furnace, thereby decreasing the equipment’s production capacity. Reason: ① Water in the syngas causes the catalyst to pulverize. ② The high ash content in the syngas causes coking of the catalyst. ③ Due to the excessively long catalyst production cycle in the conversion furnace, the catalyst breaks down or the bottom gas collector gets clogged. 11. Increase in the temperature of the converter bed layer: Reasons: ① Sudden increase in the oxygen or CO content in the syngas. ② The syngas meets the reduction requirement, and the space velocity is reduced. ③ The water vapor ratio suddenly decreased. Treatment: ① During gasification, pay attention to adjusting the composition of the syngas. ② Increase the setting of TV1505 on the DCS; if the furnace temperature continues to rise, reduce the manual valve for syngas entering the raw material gas preheater E1502. ③ Increase the water-to-vapor ratio to bring it within the specified range. 12. The bed temperature of the converter cannot be increased. Reasons: ① The water-to-gas ratio of the syngas is too high. ② Syngas contains water. ③ The catalyst has been in use for too long and has aged. Treatment: ① Vaporization to reduce the water vapor ratio. ② Check whether the gasification scrubber tower T1301 is wet. ③ If the catalyst has exceeded its service life, the catalyst temperature should be kept at its upper limit; if the temperature still cannot be increased and the outlet CO level remains difficult to control, then the catalyst needs to be replaced.

Isn’t the material upstairs in DOC format?～