Workshop Operator Test Questions

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Workshop Operator Test 1: Multiple Choice Questions 1. Which of the following substances is an organic compound? ( ). A. CO B. H2CO3 C. CH3COOH D. Na2CO3 Answer: C 2. Based on the design pressure of pressure vessels, those with a pressure within ( ) are considered medium-pressure vessels. A. 1.6Mpa≤P＜10Mpa B. 10Mpa≤P＜100Mpa C. P≥100Mpa Answer: A 3. In the event of someone getting an electric shock during production, what should be done first? A. Immediately report to management or the relevant departments B. Quickly disconnect the affected person from the power source C. Call the hospital right away Answer: B 4. The pressure gauge on a container must be inspected at least (　　) times per year. A. One B. Two C. Three Answer: B 5. The safety valve should be installed vertically at the （　　） position of the steam drum. A. Highest B. Lowest C. Middle Answer: A 6. Scale is formed by the salts of （　　） ions in water. A. All metals B. Calcium and magnesium C. Copper and iron Answer: B 7. With all other conditions remaining constant, increasing the temperature will cause the reaction equilibrium to shift in the ( ) direction. A. Heat release B. Heat absorption C. Neither heat absorption nor heat release Answer: B 8. The valve that is not suitable for regulating fluid flow and transporting materials containing particles is ( ). A. Plug valve B. Globe valve C. Gate valve Answer: C 9. In a shell and tube heat exchanger, the most common flow direction of the fluids is ( ). A. Counterflow B. Cross-flow C. Co-flow. Answer: A 10. For containers containing toxic, flammable substances, or those that can pollute the environment, ( ) safety valves should be used. A. Fully sealed type B. Semi-sealed type C. Open type Answer: A 11. The setting pressure of a pressure vessel’s safety valve should be ( ) the design pressure of the vessel. A. Less than B. Equal to C. Greater than Answer: A 12. When selecting the range of a pressure gauge, it should be noted that when the pressure being measured is relatively stable, the maximum pressure value should not exceed （ ） of the gauge’s range. A. 1/3 B. 2/3 C. 3/4 D. 1/4. Answer: C 13. When installing a rotameter, it should ( ). A. Vertical installation B. Horizontal installation C. Any installation Answer: A 14. A jet pump operates based on the principle of ( ) during fluid flow. A. Static pressure energy is converted into kinetic energy. B. Kinetic energy is converted into static pressure energy. C. Thermal energy is converted into static pressure energy. Answer: A. 15. To measure the flow rate of a liquid, the pressure taps of a orifice plate flow meter should be placed at ( ). A, upper part; B, lower part; C, middle part. Answer: B. 16. When a centrifugal pump is operating with a constant flow rate, its head should be ( ) compared to the effective head required by the pipeline. A. Greater than the effective head required by the pipeline; B. The same; C. Less than the effective head required by the pipeline. Answer: A. 17. When the density of the medium transported by a centrifugal pump changes, which parameter also changes? ( ) A. Flow rate B. Head C. Shaft power Answer: C 18. The blades of centrifugal pumps are mostly ( ) blades. A. Forward B. Backward C. Radial Answer: B 19. The pump outlet pressure is in a ( ) relationship with the head. A, directly proportional B, inversely proportional C, unrelated Answer: A 20. The volume of an object per unit mass is called the object’s ( ). A, density; B, specific volume; C, specific gravity. Answer: B. 21. For a centrifugal pump, if it is now used to transport liquids with a viscosity higher than that of water, then the pump’s head will ( ). A, decrease B, increase C, remain unchanged Answer: A 22. The noise level at the work sites in the production workshops and work areas of industrial enterprises shall not exceed ( ). A, 65 decibels B, 85 decibels C, 75 decibels D, 100 decibels Answer: B 23. The brown coloring on the cartridge of a filter-type gas mask is used to prevent ( ). A. Carbon monoxide B. Ammonia and hydrogen sulfide C. Organic compounds; D. Acidic gases. Answer: C 24. When selecting a pressure gauge, what multiple of the measured value should the gauge’s range be? ( ) A. 1.2 B. 1.5 C. 2 D. 2.2 Answer: B 25. In chemical production, pipes and valves are generally connected using ( ) connection. A, flange type; B, welded type; C, socket-type; D, threaded type. Answer: A. 26. For situations where there is not a large temperature difference between the tube side and the shell side, and where the material flowing in the shell side is relatively clean, a （） heat exchanger can be chosen. A. Floating head type B. Fixed tube sheet type C. U-tube type D. Shell and tube type Answer: B 27. When dealing with high-pressure media in which scaling is unlikely to occur in the tube side, and when there is a large temperature difference between the tube side and the shell side, a （） heat exchanger should be used. A. Fixed tube sheet type B. U-tube type C. Floating head type D. Sleeve type Answer: B 28. With all other conditions remaining unchanged, increasing the temperature will cause the reaction equilibrium to shift in the ( ) direction. A. Exothermic B. Endothermic C. Neither endothermic nor exothermic Answer: B 29. What is commonly used in industry to indicate the water content in gaseous substances containing water? ( ) A. Percentage B. Density C. Mole ratio D. Dew point Answer: D 30. The pressure inside a container is 1 MPa; to measure it, which range of pressure gauge should be used? A. 0-1 MPa B. 0-1.6 MPa C. 0-2.5 MPa D. 0-4.0 MPa. Answer: B 31. In chemical production, when operations are running normally, the flow of fluid in the pipes is usually of ( ) flow. A, Stable B, Unstable C, Stagnant Answer: A 32. When liquid flows through a pipe, energy loss occurs, and this is due to the fact that the liquid has ( ). A, mass B, viscosity C, static pressure Answer: B 33. Gases also have viscosity, and their viscosity generally increases as the temperature rises. A, Decrease B, Increase C, Unchanged Answer: B 34. Which of the following flow meters does not belong to the differential pressure type of flow meters? A. Orifice flow meter B. Nozzle flow meter C. Venturi flow meter D. Rotameter Answer: D 35. There is a centrifugal pump that originally rotated at 3000 revolutions per minute; now it operates at 2000 revolutions per minute. What is the pump’s flow rate compared to before? A, 2/3 B, 1/2 C, unchanged Answer: A 36. In a shell and tube heat exchanger, the tubes can be arranged in either in-line or cross-flow patterns; when the heat transfer area remains constant, the ( ) arrangement results in a slightly higher convective heat transfer coefficient. A, in series B, out of series C, cannot be determined Answer: B 37. The reason why feed pipes for supplying material to oil tanks usually use a \"bottom inlet\" rather than injecting the material from the top of the tank is ( ). A To prevent foam formation B To prevent the material from vaporizing C To prevent leakage of material D To prevent static electricity Answer: D 38. The purpose of closing the pump outlet valve before starting a centrifugal pump is ( ). A Reduce starting power B Increase the pressure at the pump outlet C Prevent sudden changes in system pressure D Prevent the suction line from being suddenly emptied. Answer: A 39. In the three-stage filtration of lubricating oil, the filter mesh used from the oil container to the filling point is ( ). A. 40 mesh B. 60 mesh C. 80 mesh D. 100 mesh. Answer: D 40. What concentration limit should be maintained in the waste alkali to prevent salt crystallization? A、30% B、15% C、25% D、20%. Answer. II. Fill in the blanks. 1. The basic methods of extinguishing fires are ( ), ( ), ( ). Answer: Cooling method ； asphyxiation method ； Isolation method 2: Static electricity is generated by ( ). Answer: Friction. 3. Personnel who enter production positions must undergo three levels of training, namely ( ), ( ), and ( ) training. Answer: Plant level ； workshop ； Team 4: When hot work is required for equipment maintenance, it is necessary to obtain ( ) first. Answer: Fire Permit. 5. There are three ways by which toxins can enter the human body, namely ( ), ( ) and ( ). Answer: Respiratory tract ； skin ； Digestive tract 6. Heat transfer that occurs through relative displacement driven by fluid flow is called ( ). Answer: Convective heat transfer. 7. In a distillation tower, the heat and mass exchange between the gas and liquid phases takes place at ( ). Answer: 8. Distillation columns can be roughly divided into ( ) columns and ( ) columns. Answer: Plate-type ； Filler 9: The three states of aggregation of matter are ( ), ( ) and ( ). Answer: Solid state ； liquid ； Gaseous state 10: The amount of fluid that passes through a cross-section of a pipe per unit of time is called ( ). Answer: 11. The unit of volumetric flow rate is ( ), and the unit of mass flow rate is ( ). Answer: m3/S ； Kg/S 12. The two forms of convective heat transfer are ( ) and ( ). Answer: Natural convection ； Forced convection 13, 1 meter = ( ) decimeters = ( ) centimeters = ( ) millimeters = ( ) feet ； 2.2 m² = ( ) dm² = ( ) cm² ； 0.5 kilomoles = ( ) moles. Answer: 10 100 1000 3.28 200 20000 500 14. The total mass of the substances that participate in a reaction is equal to the total mass of the substances formed as a result of the reaction; this is known as the ( ) law of substances. Answer: Law of conservation of mass. 15. In any substance, as long as it contains 6.02×1023 particles, the amount of this substance is called (), and it is expressed in (). Answer: 1 mole ； Mol 16: The smallest particle that retains all the chemical properties of a substance is called its ( ). Answer: With a molecular weight of 17, nitrogen is non-toxic; however, being in a container or area filled with high concentrations of nitrogen can cause ( ) phenomena. Answer: Asphyxiation. 18. When emptying a container, one should first ( ), and then ( ). Answer: Pour the liquid ； Pressure release 29: The conditions necessary for combustion are ( ), ( ), and an energy source (such as impact, friction, an open flame, etc.). ) Answer: Flammable substances ； Oxidizing agents 20: When entering the equipment tank or other devices for maintenance work, it is necessary to obtain ( ) and have a dedicated person monitor from outside. Answer: “Work Permit for Entering Equipment”. 21. Three conditions must be met for combustion: (), (), (). Answer: Combustible materials ； oxidizer ； Ignition source 22: When the skin is contaminated with acids or alkalis, it should be immediately rinsed with a large amount of ( ). Answer: Clear water. 23. In areas prone to explosions, it is not allowed to wear clothing that is easy to ( ). Answer: Static electricity is generated. 24. When using a carbon dioxide fire extinguisher to put out fires, one’s hands must be held at the ( ) of the nozzle to prevent skin frostbite. Answer: 25. On the wooden handle; control of the temperature of the sensitive plate is mostly achieved using ( ) method. Answer: Change the amount of heating medium used. 26. DCS primarily makes use of ( ) technology, ( ) technology, and ( ) technology. Answer: Computer ； Communication ； Control 27: The actuator consists of ( ) and ( ). Answer: Actuator ； Control valves 28 and check valves are commonly used in （ ） situations. Answer: Reverse flow of the fluid is not allowed. 29. Based on different distillation methods, they can be divided into three categories: ( ), ( ), and ( ). Answer: Simple distillation ； distillation ； Special distillation 30: The basic methods of heat transfer are ( ), ( ) and ( ). Answer: Heat conduction ； Convection heat transfer ； Radiative heat transfer 31: As the operating pressure increases, the concentration of heavy components in the gas phase ( ), while the concentration of light components in the gas phase ( ). Answer: Reduce ； 32. During the distillation process, the component that is obtained at the top of the tower is the （ ） component, while the component with higher purity is obtained at the bottom of the tower, which is the （ ） component. Answer: Volatiles with higher purity ； Difficult to volatilize 33. The three most common types of shell-and-tube heat exchangers are ( ), ( ) and ( ). Answer: Fixed tube sheet type ； floating head type ； For U-tube type, 34: the area above the feed plate in a continuous distillation column is referred to as ( ), while the area including the feed plate itself is referred to as ( ). Answer: Distillation section; stripping section. 35. The operating pressure of a distillation tower is mainly determined by ( ). Answer: The properties of the material being processed. 36. To control the temperature of the sensor plate, it is usually done by adjusting the amount of ( ). Answer: Heating medium 37. Under standard conditions, the volume of 1 mol of gas is ( ). Answer: 22.4L 38. The phenomenon of vaporization that occurs only on the surface of a liquid is called ( ), while the phenomenon of vaporization that occurs both inside and on the surface of a liquid is called ( ). Answer: Evaporation; Boiling. 39. The unit of absolute temperature is ( ), the unit of Celsius temperature is ( ) (expressed in symbols), and the relationship between the two is ( ). Answer: K; °C; K = °C + 273.15°C. 40. If no external forces act on an object, it always remains in a ( ) or ( ) state, until an external force forces it to change its state of motion; this is known as Newton’s first law. Answer: At rest; uniform linear motion. 41. Flow rate is divided into ( ) flow rate and ( ) flow rate. Answer: Volume; mass. 42. The heat absorbed (or released) when the temperature of 1 gram of pure water increases (or decreases) by 1℃ is called ( ). Answer: 1 card. Watt is the unit for ( ), and kilowatt-hour is the unit for ( ); 1 kilowatt hour equals ( ) degrees. Answer: Power ； work ； 1 44. Organic compounds refer to the general term for compounds that contain ( ) elements. Answer: Carbon 45; the two forms of chemical reactors are ( ) and ( ). Answer: Adiabatic reactor ； In a non-adiabatic reactor 46, water should not be used to extinguish fires involving electrical equipment; if water must be used to put out such fires, it is necessary to first ( ). Answer: Cut off the power supply. 47. According to the suction method of the pump, centrifugal pumps can be divided into ( ) and ( ) categories. Answer: Single-suction pump ； Double-suction pump 48: The main factors affecting gas density are ( ), ( ), ( ). Answer: Gas molecular weight ； Temperature ； Pressure 49: When using a pressure-type level gauge to measure the liquid level, if the installation height of the gauge differs from the zero level of the liquid, it is necessary to carry out ( ). Answer: Correction of the indicated value 50. During routine maintenance of pressure gauges, if the production unit is shut down, the isolation valve between the pressure gauge and the pressure tapping point should be (). Answer: Turn them all off. 51. When installing a pressure gauge, it is first necessary to select an appropriate pressure sampling point. When taking pressure readings from horizontal pipes, if the medium is gas, the pressure measurement point should be located at the ( ) of the pipe; if the medium is liquid, the pressure measurement point should be located at the ( ) of the pipe. Answer: Upper half, lower half. 52. The greater the volume of liquid flowing through the pipe per unit of time, the higher the flow velocity; when the flow rate remains constant, the larger the cross-sectional area of the pipe, the higher the flow velocity. Answer: Larger, Smaller. 53. The factors that affect the flow state of a fluid are ( ), ( ), ( ) and ( ). Answer: Pipe diameter; fluid flow velocity; fluid viscosity; fluid density. 54. A differential pressure flow meter is based on the ( ) principle of fluid flow, and it uses the ( ) generated when the fluid passes through a throttling device to measure flow rate. Answer: Throttling, pressure difference 55. The boiling point of a liquid is closely related to air pressure; as air pressure increases, the boiling point ( ), and as air pressure decreases, the boiling point ( ). Answer: Increase, Decrease. 56. The basic parameters of a valve are ( ), ( ), ( ). Answer: Nominal diameter, nominal pressure, applicable medium. 57. What is the function of a steam trap? Answer: To prevent steam from passing through and to remove condensate. 58. Pressure vessels must be inspected regularly, and these inspections are divided into ( ), ( ) and ( ). Answer: External inspection, internal inspection, comprehensive inspection. 59. For pipelines used for transporting media at high temperatures over long distances, the best option for thermal compensation is ( ). Answer: Expansion joint. III. True or False Questions: 1. When the concentration of combustible substances in air is higher than the upper explosion limit, no explosion will occur, but combustion is possible. ( ) Answer: √ 2. Static electricity can cause explosions, fires, and personal injuries. ( ) Answer: √ 3. When the skin is in contact with acids or alkalis, it should be washed immediately with clean water. ( ) Answer: √ 4. The lower the ignition point, the easier it is for something to catch fire. ( ) Answer: √ 5. Closed-type safety valves are suitable for environments with flammable, explosive, toxic, or corrosive media. ( ) Answer: √ 6. Oxygen is a flammable gas. ( ) Answer: × 7. The pressure measured on the basis of absolute vacuum is called absolute pressure. ( ) Answer: √ 8. Centrifugal pumps equipped with open or semi-open impellers are used to transport slurries or liquids containing solid suspensions. （　　） Answer: √ 9. For a pure liquid, the saturated vapor pressure at a certain temperature is equivalent to the volatility of that liquid. （　　） Answer: √ 10. The greater the heat transfer area of a heat exchanger, the more heat is transferred. ( ) Answer: √ 11. The fixed-tube-sheet heat exchanger is suitable for use when there is a large temperature difference between the two fluids, and when the materials involved are highly corrosive. ( ) Answer: Wrong. 12. The boiling point of a fluid is related to atmospheric pressure; as the pressure increases, the boiling point rises. (　　) Answer: √ 13. Before starting a diaphragm pump, it is necessary to fill the pump and release air from it. ( ) Answer: × 14. The value of the reflux ratio plays an important role in determining the number of plates in the distillation column as well as the location of the feed. (　　) Answer: √ 15. When starting a pump, it is necessary to follow the principle of starting the pump first and then opening the outlet valve. (　　) Answer: × 16. The distillation process involves both heat transfer and mass transfer processes. ( ) Answer: √ 17. The higher the steam pressure, the higher its corresponding saturation temperature as well. (　　) Answer: √ 18. When the orifice plate is blocked, the flow rate indicated by the instrument will be lower than the actual value. (　　) Answer: × 19. The flow rate of a reciprocating pump is related to the pump’s head. (　　) Answer: × 20. The value of the reflux ratio plays an important role in determining the number of plates in the distillation column as well as the location of the feed. (　　) Answer: √ 21. When starting a pump, it is necessary to follow the principle of starting the pump first and then opening the outlet valve. (　　) Answer: × 22. Before initially starting the diaphragm pump, it is necessary to close the inlet valve and adjust the zero point. ( ). Answer: √ 23. The head of a reciprocating pump is theoretically infinite. （　　） Answer: √ Four noun explanations 1. What is atmospheric pressure, and what is standard atmospheric pressure? Answer: Since air has weight, the atmosphere in the upper layers of the Earth exerts a certain pressure on the Earth’s surface; this pressure is known as atmospheric pressure. The average pressure at sea level at a latitude of 45 degrees Celsius is defined as standard atmospheric pressure, or physical atmospheric pressure. 1 physical atmosphere = 760 millimeters of mercury = 1.033 engineering atmospheres. 2. What is solubility? Answer: Generally, the amount of solute that can dissolve in a certain amount of solution at a specific temperature and pressure to reach a state of dissolution equilibrium is called solubility. 3. What is pressure? Answer: The vertical force acting per unit area is called pressure. For a gas, its pressure is generated by the collision of gas molecules inside the container with the container walls. For a liquid, its pressure is generated by the liquid inside the container pressing against the container walls. 4. What is an interface? Answer: There are two liquids with different densities and that are immiscible with each other inside the container; the liquid with the higher density sinks to the bottom, while the liquid with the lower density floats on top, forming a boundary layer between the two liquids. The surface that separates liquids is called an interface. 5. What is specific gravity? Answer: The ratio of the density of an object to the density of pure water at 4°C is called specific gravity. 6. What is density? Answer: The mass per unit volume of a fluid is called the density of the fluid. 7. What is the flash point? Answer: Flash point: The temperature at which a mixture of vapor and air above the surface of a flammable liquid comes into contact with an open flame, resulting in the first occurrence of a flame flash, is known as the flash point of that liquid, also referred to as the ignition point. 8. What is distillation? Answer: The process by which a mixture is subjected to multiple cycles of partial vaporization and partial condensation, thereby separating the solution into its purer components, is called distillation. 9. What is the upper explosion limit? Answer: The highest concentration of combustible gas or vapor in air at which a flame can propagate, that is, the maximum value at which energy can be transmitted gradually. 10. What is the lower explosion limit? Answer: The lowest concentration of combustible gas or vapor in air at which a flame can propagate, that is, the minimum value at which energy can spread gradually. 11. What is a chemical burn? Answer: Chemical substances on human skin or eyes can deprive tissues of the water necessary for cell survival, thereby damaging the vitality of the skin; this is known as chemical burns. 12. What is DCS? Answer: DCS is the abbreviation for Distributed Control System. It can handle all conventional control tasks, as well as perform advanced control of units such as cracking furnaces, quenching systems, separation systems, and compression systems. It also carries out tasks such as data collection, graphic display, and data printing. 13. What is a sensitive plate? Answer: The so-called sensitive tray is the one on which the temperature changes the most when there are variations in the operation of the entire tower; in other words, it is the tray on which the composition changes the most, making it the most sensitive. By controlling it with the sensor board temperature, it is possible to anticipate trends in product quality changes and make adjustments in advance. 14. What is tower flooding? Answer: Due to an excessive liquid load, the liquid fills the entire tray, causing the liquids on the upper and lower trays to merge together; this completely destroys the distillation effect. This phenomenon is known as tray flooding. 15. What is tray washing? Answer: Due to an excessive gas-phase load, the heavier components within the tower are carried to the top of the tower, resulting in substandard product quality; this phenomenon is known as tower flooding. 16. What is backflow? Answer: In order for the tower to achieve a certain level of separation accuracy and ensure thorough contact between the gas and liquid phases on the tray, thereby enabling mass and heat transfer, a portion of the liquid must circulate within the tower; this portion of liquid is known as reflux. Depending on the method used to remove the reflux heat, it is divided into cold reflux and hot reflux. 17. What is the boiling point of distillation? Do something? Range? Answer: When oil is heated under specified conditions in an Enneberg distillation apparatus, the temperature of the gas phase at the moment the first drop of condensate appears is called the initial boiling point. The highest temperature of the gas phase that can be reached at the end of the distillation process is called the final boiling point or dry point. The temperature range from the initial boiling point to the dry point is referred to as the boiling range. 18. What are the “five fixed principles” for lubrication? Answer: The “five fixed principles” for lubrication refer to fixing the location, quality, quantity, person in charge, and timing. V. Short-answer Questions 1. What are the criteria for determining that medium-pressure steam pipeline heating is complete? Answer: Generally, when the temperature in the pipeline exceeds the super saturation temperature of high-pressure steam by more than 50°C, it can be considered satisfactory for warming the pipeline. 2. How does circulating cooling water prevent scaling? Answer: The main protective measures are: (1) Pre-treating the make-up water supplied to the system in order to reduce the levels of Ca and Mg ions in it. (2) Adding scale-inhibiting agents to the circulating cooling water. 3. What are the main performance indicators of centrifugal pumps? Answer: (1) Flow rate (Q) refers to the volume of fluid discharged by the pump per unit of time ； (2) Head (H) refers to the energy that the pump can impart to a unit weight of liquid ； (3) Shaft power (W) refers to the power obtained by the pump from the motor ； (4) Efficiency (η) refers to the ratio of the pump’s useful power to its shaft power. 4. The check valve at the pump outlet usually has a bypass valve; what is its purpose? Answer: There are mainly two uses: (1) Anti-freezing during normal operation in winter (pumps are usually operated in one active and one standby configuration; during winter, the standby pump has its inlet and outlet valves as well as the bypass valves of the check valves slightly opened, allowing some of the fluid to flow back). (2) When the pump is shut down, this valve is opened to empty the fluid in the pump’s outlet pipeline. 5. How to prevent the generation of static electricity? Answer: (1) Limit the flow rate, restrict charge accumulation on the human body, and employ electrostatic shielding. (2) Prevent the accumulation of charge, such as by grounding, bridging, or using static electricity additives. (3) Avoid or prevent hazardous factors in the surrounding environment ； Restrict the use of or remove hazardous materials ； Improve ventilation conditions by replacing or filling with inert gas. 6. What are the characteristics of a Distributed Control System (DCS)? Answer 1). Display, operation centralized ； (2). Strong control functionality ； (3) Easy data processing ； (4). The system has a flexible structure, making expansion easy ； (5). High reliability ； (6). It has a self-diagnosis function. 7. How to switch between manual and cascade mode for the instruments on the DCS? Answer: Only a switch from cascade to manual mode is possible; the reverse is not feasible. When the instrument is in cascade mode, pressing the corresponding manual button and confirmation button below the instrument will change it from cascade mode to manual mode. 8. What is the sealing principle of flange connections? Answer: The sealing in flange connections is achieved by using a gasket that is softer (compared to the flange itself); when under pressure, this gasket deforms and fills in the uneven gaps between the two sealing surfaces, thereby preventing fluid from leaking and achieving a sealed connection. Therefore, the sealing of flange connections is achieved through the sealing surface gasket and the compressive force that deforms the gasket, with the compressive force being obtained by tightening the bolts. 9. What precautions should be taken when using nitrogen? Answer: When using nitrogen, it is necessary to pay attention to the pressure in the nitrogen system to prevent materials from flowing back into it. Proper management of nitrogen in the connected equipment is essential to avoid nitrogen from entering devices that are under maintenance, which could lead to nitrogen asphyxiation accidents. Under normal circumstances, it is not allowed to fix nitrogen pipelines to material pipelines; instead, rubber hoses are used for temporary connections, which are removed once they are no longer needed. 10. What are the control parameters for the rainwater drainage system? Answer: Requirements for rainwater discharge: Oil Ca2+ > Mg2+ > Al3+ > Fe3+; H+ > Fe3+Al3+ > Ca2+ > Mg2+ > Na+; Fe3+ > Al3+ > Ca2+ > Mg2+ > Na+ > H+. 20. The water sent to the boiler is called (2) feed water. (1) Make-up water; (2) Feed water; (3) Boiler water. 21. Water from which calcium and magnesium salts have been removed is called (2) softened water. (1) Purified water; (2) Softened water; (3) Deionized water. 22. Untreated natural water is called (1) raw water. (1) Raw water; (2) Make-up water; (3) Tap water. 23. When natural water is classified according to its salt content, water with a salt content of 200~~~500 mg/L belongs to (2) water with moderate salt content. (1) Water with low salt content; (2) Water with moderate salt content; (3) Water with high salt content. 24. When natural water is classified according to its hardness, water with a hardness of 1~~3 mmol/L belongs to (1) soft water. (1) Soft water; (2) Water with moderate hardness; (3) Hard water. 25. When aluminum salts are used as coagulants, the optimal pH value is (2) 6.5~~~8. (1) 6.0~~6.5; (2) 6.5~~~8; (3) Above 8. 26. After strongly acidic H-type cation exchange resins become ineffective, (2) their volume decreases. (1) Their volume increases; (3) Their volume remains unchanged. 27. When ion exchange resins are contaminated by iron, aluminum, and their oxides, (1) their color darkens. (1) Their color lightens; (3) Their color remains unchanged. 28. When cation exchange resins are contaminated by active chlorine during use, (1) their color lightens and their volume increases. (1) Their color darkens and their volume increases; (3) Their color remains unchanged while their volume increases. 29. After raw water is treated with Na-type ion exchangers, the alkalinity in the water (3) remains unchanged. (1) Increases; (2) Decreases; (3) Remains unchanged. 30. In a chemical desalination system, the arrangement of the exchangers should theoretically be (1) the cation exchanger comes before the anion exchanger. (1) The cation exchanger is placed before the anion exchanger; (2) The anion exchanger is placed before the cation exchanger; (3) In general, either order is acceptable.

IV: Term Explanations
1. Total hardness: Refers to the total amount of calcium and magnesium ions present in water. Total hardness is the sum of temporary hardness and permanent hardness. Primary 2: Temporary hardness: the amount of bicarbonates of calcium and magnesium in water; hence, temporary hardness is also known as carbonate hardness. Upon heating, bicarbonates decompose into insoluble carbonate precipitates. Intermediate 3: Permanent hardness refers to the amount of non-carbonate forms of calcium and magnesium in water (such as chlorides and sulfates of calcium and magnesium), also known as non-carbonate hardness. When heated, these non-carbonates cannot precipitate out of the water. Intermediate 4: Total alkalinity refers to the sum of hydroxide, carbonate, and bicarbonate ions in 1 liter of water. Intermediate 5: Salt content refers to the total amount of cations and anions in 1 liter of water, that is, the total amount of all salts dissolved in 1 liter of water. Intermediate 6: pH value: A method used to indicate the concentration of hydrogen ions in a solution. Level 7: Total solids: The total amount of solid residue remaining after the evaporation of suspended particles and dissolved solids in water. Unit: mg/L. Beginner level 8. Flow meter: An instrument used to measure the flow rate of substances is called a flow meter. It operates based on certain principles and mechanisms. Question 4: Short-answer questions. 1. What are the commonly used methods for water purification? Intermediate Answer: Water purification mainly involves removing suspended particles and colloidal substances that cause turbidity. Common purification methods include precipitation and filtration. 2. What is the precipitation method? Primary: Answer: Under the action of gravity, suspended particles with a density greater than 1 in water settle and separate; this method is called sedimentation. The precipitation method is divided into natural precipitation and coagulation precipitation. 3. What are the common coagulants used in water purification? Beginner Answer: Common coagulants used for water purification are aluminum sulfate and ferrous sulfate. 4. What are the commonly used coagulants in water purification? Intermediate: Answer: Common coagulants include chlorine, quicklime, activated water glass, bone glue, polyacrylamide, etc. 5. How to prepare a coagulant solution? Beginner Answer: Dissolve the coagulant in water and stir it. For insoluble coagulants, or when the water temperature is low in winter, hot water or steam can be used for heating. 6. What is the process flow for circulating cooling water? Primary level: The process cooling water from units such as synthesis, compression, and transformation enters the cooling tower through return pipes. It is sprayed downward via nozzles, forming a water film within the filler material in the tower. This water film comes into contact with the air drawn in from the bottom of the tower by the exhaust fan installed at the top of the tower; the air absorbs the heat from the hot water and is then discharged into the atmosphere at the top of the tower. The water, having been cooled by the air, collects in the collection tank at the bottom of the tower. Depending on the water quality, a water stabilizer is added, along with an appropriate amount of fresh water, which is then pumped to various processing units by cold water pumps. To reduce the turbidity of the circulating water, 1% to 5% of it is filtered through a side filter to remove impurities before being returned to the collection tank. 7. What are the key points for the proper operation of circulating cooling water? Intermediate Level Answer: ① Control of circulating water – by means of analysis and regular inspections, monitor the quality of the circulating water; periodically check the water quality stabilizers and add fresh water to ensure that the circulating water does not develop scale, suffers from corrosion, or is infested with algae or sludge. ②Control of the circulating water temperature is crucial, as it determines the operation status of the cooling tower; therefore, it is essential to keep the cooling tower equipment in good condition and ensure that the exhaust fans at the top of the tower are functioning properly. ③Strengthen water quality analysis, conducting it twice per shift. 8. Why pre-coating? Intermediate: Answer: After the system is cleaned and free of impurities, pre-coating is carried out. The purpose of pre-coating is to form a complete corrosion-inhibiting protective layer on the surfaces of metal equipment and pipes, thereby reducing corrosion. 9. What precautions should be taken when pre-coating? Advanced Answer: ① Control the calcium ion concentration; a low calcium ion concentration results in poor pre-coating performance. Generally, the calcium ion concentration in the pre-coating circulating water should be kept between 40 and 80 mg/L. ② Control the pH value. A low pH of the pre-coating circulating water can activate the metal surface, which is beneficial for film formation; therefore, the pH value should be maintained between 5.5 and 6.5. ③The turbidity of the pre-coating water should be low, generally not exceeding 10 mg/L, as high turbidity indicates an abundance of impurities in the water, which hinders film formation and accelerates corrosion. ④The water temperature should not be too low; it is generally between 20 and 50°C. 10. What are the reasons for the excessive quality of circulating cooling water? How to handle it? Advanced Answer: The main reasons for excessive water quality issues are: ① Instability of water quality and a formulation that does not match the characteristics of the water. Water quality stability and the formulation must be determined through simulation tests; if the water quality changes while the formulation remains unchanged, it will affect the quality of the circulating water ； ②The quality of the reagents is unstable ； ③Chemical dosing is not carried out in a timely manner, and the amount of chemical added does not correspond to the requirements determined by water quality tests ； ④The flow rate in the side filter tank is low ； ⑤Dust gets blown into the circulating water system ； ⑥Leakage from cooling equipment, such as ammonia or copper melt entering the circulating water system ； ⑦Wash away dirt in circulating water. Treatment method: ① Select a water quality stabilizer formula suitable for the water quality to ensure stable quality of the chemical ； ②Strict water management. Conduct tests on the circulating water as required, and add chemicals in a timely manner ； ③Adjust the amount of water used for bypass filtration as needed, so that the circulating water can be filtered once every 1 to 2 days ； ④Install windbreak walls in areas where dust is likely to be inhaled ； ⑤Strengthen management to prevent materials from entering the circulating water, and eliminate the practice of using it to wash away dirt manually. 11. What are the characteristics of biological enzymes? Beginner Answer: As biological catalysts, enzymes possess, in addition to the characteristics common to other catalysts such as accelerating reaction rates, not altering the chemical equilibrium of reactions, and reducing the activation energy required for reactions, the following properties as well: (1) High catalytic efficiency ； ⑵Highly specific ； ⑶Prone to inactivation ； ⑷Enzyme activity is under regulatory control ； ⑸Catalytic activity is related to coenzymes, prosthetic groups, and metal ions; if these are removed, the enzyme becomes inactive. 12. What are the environmental factors for microbial growth? Beginner Answer: In addition to nutrients (carbon, nitrogen, phosphorus, inorganic salts), microbial growth also requires suitable environmental factors such as temperature, pH value, dissolved oxygen, osmotic pressure, and redox potential (ORP) in order to survive. If environmental conditions are abnormal, it will affect normal physiological activities and may even lead to mutation and death. 13. What measures can be taken to soften water when its hardness is too high in water treatment? Intermediate: Answer: When the hardness of the raw water (measured as non-carbonate hardness) is low, lime softening can be used ； When the hardness of the raw water (as measured in terms of non-carbonates) is high, the lime-soda softening method can be used ； When the alkalinity in the raw water is greater than its hardness, the lime-gypsum softening method can be used ； When the concentrations of heavy metal ions such as mercury, zinc, copper, lead, and arsenic are high, the sulfide precipitation method can be used for treatment; common precipitants in this method include hydrogen sulfide, sodium sulfide, and potassium sulfide. 14. What are the methods for controlling the growth of microorganisms in water bodies? Beginner Answer: Methods for controlling microorganisms: adding biocides ； Use corrosion-resistant materials ； Control the oxygen content, pH value, suspended solids, and nutrients for microorganisms in water bodies. 15. What are the properties and main performance indicators of activated carbon? Beginner Answer: Activated carbon has a very large specific surface area (800–2000 m2/g) as well as numerous organic functional groups (hydroxyl groups, carbonyl groups, carboxyl groups, phenolic hydroxyl groups, quinone-type carbonyl groups, cyclic peroxyl groups, and structurally complex basic groups), which enables it to exhibit excellent adsorption properties. Activated carbon is essentially a non-polar substance, so it can more easily adsorb organic compounds. Activated carbon has high strength, is not easily broken, has good wear resistance, is resistant to water immersion, and is insoluble in acids and bases. 16: How to prevent acid mist from forming on the hydrochloric acid storage tank? Intermediate: Answer: When hydrochloric acid is used as a regenerant for cation exchangers, smoke often forms on the storage tank containing the hydrochloric acid; this not only causes severe corrosion to the equipment but also leads to air pollution. There are generally two methods to prevent the formation of acid mist: installing acid mist absorbers and using paraffin oil seals. 16. What *hi-dao-cong-ci? Ke-cong-ci? Di-cheng-wu-qi-zhi? Mu-gang-zhong-wen-jian? Kong-xie ————————————— Statement: This article is posted by “Xuehai Xiaotu”, who takes full responsibility for any consequences that may arise from this action. There is no royal road to learning except through diligence. 26. What are the main methods of preprocessing? Beginner Answer: (1) Pre-sedimentation, (2) Coagulation, (3) Clarification, (4) Filtration, (5) Softening, (6) Disinfection. 27. What is a single-pass mechanical filter? Hold high. Answer: A single-stream mechanical filter is the simplest type of filter, with only one inlet and one outlet. The body of a single-stream filter is a cylindrical steel container, equipped with a water inlet device and a drainage system. Sometimes there is also a device for introducing compressed air. Various necessary pipes, valves, and other components are installed outside the device. 28. What are the reasons for the periodic decrease in the water treatment capacity of a mechanical filter during operation? Advanced Answer: 1. Clogging of the filter by suspended solids. 2. Insufficient backwashing intensity or incomplete backwashing. 3. Excessively long backwashing cycles. 4. Deviation in flow caused by damage to the water distribution and drainage systems. 5. Too low filter bed height. 6. Sudden increase in the turbidity of the raw water (e.g., a sharp rise in suspended solids during flood periods). 29. What are the reasons for insufficient flow rate in mechanical filters during operation? Intermediate: Answer: 1. Excessive head loss in the water inlet pipes and drainage system. 2. Contamination, blockage, or caking at the upper part of the filtration layer. 30. What are the reasons for the loss of filtering sand during backwashing in a mechanical filter? Intermediate: Answer: 1. Excessive backwashing intensity; 2. Damage to the drainage or water distribution system, resulting in uneven distribution of backwash water across the filter surface