Call for training lesson plans

In 2007, I did develop a set of training materials specifically designed for the operators at our company. It went through numerous revisions before it was printed; if possible, I’ll upload it to a cloud storage service for everyone to refer to. http://www.brsbox.com/filebox/down/fc/834d3942520b6985fce5dec61a767052 I have been involved in employee training for over a decade, but this is my first time compiling materials of this kind; please feel free to point out any mistakes. This post was last edited by stmm2001 on 2009-1-6 23:26]

Is employee training not important? Or have we not done well enough? I sincerely hope that more sea friends will participate.

These materials are summarized by oneself during production; there are many of them, such as lessons learned from accidents, precautions for starting up and shutting down, operating procedures, and so on

Training materials generally include two main components, namely what one should know and what one should be able to do. It should be noted that part of it is basically theoretical knowledge, which can be found in technical books. However, the corresponding parts vary from factory to factory and from plant to plant.

Operator training consists of three levels of education, as follows: 1. Plant-level education. (Imposing **production policies and plant-level production standards) 2. Workshop-level training. (Instructing workers on safety production knowledge in the workshop, as well as the workshop’s process flow and safety operating procedures, etc.) 3. Team training. (Refine workshop-level training, starting from specific details and small equipment on a broader scale.) In fact, all legitimate factories require employees to go through these three levels of training and pass the examinations before they can work with a valid certificate! Specific training plans and the like are formulated according to each company’s circumstances, so they need not be identical!

Which aspect would you like more details on: the training plan or the question bank?

For a newly established company, employee training is particularly important. A seven-day safety training program must be conducted, focusing on the safety policy, the 41 safety regulations issued by the former Ministry of Chemical Industry, with examples provided for each one； The process specifications for this production line, as well as the physical and chemical properties of the raw materials, semi-finished products, and finished products involved, along with emergency response measures ； Completed the study of the company’s relevant systems and passed the assessment. Next, systematic training is provided, with the main contents including basic chemistry (organic and inorganic), process control in production, and handling of abnormal conditions. The explanation of emergency procedures, knowledge of electrical and instrumentation systems (including DCS\PLC), environmental protection knowledge, as well as equipment knowledge (the startup and shutdown procedures and principles related to various pumps) – all together, this requires approximately 200 hours of training time. Prepare well – it’s an excellent learning opportunity for both the organizers of the training and the participants!

It mainly involves SOP training, on-site explanations, regular training sessions, and all personnel who are not at work are required to attend. It is best to have experienced masters guide new apprentices, regularly assessing their progress and putting some pressure on the masters, so that they can grow more quickly. Some external training programs can also be arranged, mainly aimed at engineers. These include training provided by well-known companies such as Emerson’s DCS, Aspen, 6 Sigma, etc. It is necessary to assess the effectiveness of such training; otherwise, many people attend these courses with the attitude of treating it as a vacation, resulting in a waste of money.

Below is the question bank I have compiled for chemical plant operators; it should be applicable in general! Share it! Workshop Operator Test Questions 1. Multiple Choice Questions 1. What are the boiling point and density of benzene? (B) A. Boiling point: 80.1, Density: 0.876 B. Boiling point: 80.1, Density: 0.879 C. Boiling point: 110.6, Density: 0.867 D. Boiling point: 80.7, Density: 0.869 2. What type of tower is the T-101 tower? (A) A. Packed tower B. Bubble column tower C. Floating valve tower D. Tray tower 3. The main process principle utilized in the production of organic benzenes in the workshop is (B) A. Distillation principle B. Fractional distillation principle C. Extraction principle D. Absorption 4. What is the product obtained from the top of the T-101 tower? (D) A. Heavy benzene B. Crude benzene C. Toluene D. Light benzene 5. Equipment in which a fluid reacts while passing through a bed of stationary solid material is called a (A) A. Fixed-bed reactor B. Fluidized-bed reactor C. Tubular reactor D. Tower reactor 6. The vacuum pump used as a pressure-reduction device in the organic benzenes workshop belongs to which category? (C) A. Steam-flow vacuum pump B. Reciprocating vacuum pump C. Water-jet vacuum pump D. Water-ring vacuum pump 7. A gauge pressure of -0.075 Mpa indicates that the actual pressure inside the container is (B) A. 75 Kpa B. 25 Kpa C. 750 Kpa D. 250 Kpa 8. The reason for cavitation in a centrifugal pump is (A) A. The installation height exceeds the design requirements B. Condensation of heat in the input medium C. Air present in the pump chamber D. Incorrect motor rotation direction 9. Before use, an oxygen respirator should be checked to ensure that the oxygen pressure is greater than (B) atm. A、80 B、100 C、30 D、50 10. The setting pressure of a safety valve is (C) times the operating pressure of the pressure vessel. A、1.00～1.1 B、1.2～1.3 C、1.05～1.1 D、0.9～1.0 11. The function of I in the instrument PIC-200 on the process flow diagram is (B) A、Recording B、Indicating C、Regulating D、Alarming 12. The reason for gas entrapment in a centrifugal pump is (A) A、Gas present inside the pump B、The fluid vaporizing at the pump inlet C、Mechanical failure 13. The filter screen of a centrifugal pump is installed (A) A、Between the inlet valve and the pump B、In front of the inlet valve C、At the pump outlet 14、Compared to heat transfer without phase change, heat transfer occurs more intensely when there is a phase change. A. There is a phase change. B. There is no phase change. C. The same. II. Fill in the blanks: 1. In the International System of Units, the unit of weight is (Newton), and 1 kilogram-force = (9.8) Newtons. 2. There are two ways of vaporization, namely (evaporation) and (boiling). 3. Heat transfer occurs due to differences in (temperature) between objects, and its basic modes include (heat conduction), (heat convection), and (heat radiation). 4. Heat transfer that relies on fluid flow for relative displacement is called (convection heat transfer), and it comes in two forms: (natural convection) and (forced convection). 5. The vaporization that occurs on the surface of a liquid is called (evaporation), while the vaporization that takes place both inside and on the surface of a liquid is called (boiling). 6. The relationship among atmospheric pressure, absolute pressure, and gauge pressure is (Absolute pressure = Atmospheric pressure + Gauge pressure). 7. The compression ratio is the ratio of the absolute pressure of the gas at the compressor’s outlet to the absolute pressure of the gas at its inlet. 8. Based on the way they draw in fluid, centrifugal pumps can be divided into two categories: single-suction pumps and double-suction pumps. 9. When the pressure inside the container under test is greater than the external atmospheric pressure, the pressure measuring instrument used is called a (pressure gauge); when the pressure inside the container under test is less than the external atmospheric pressure, the pressure measuring instrument used is called a (vacuum gauge). 10. The function of the impeller in a centrifugal pump is to transfer (the mechanical energy of the prime mover) to the liquid, thereby increasing both the (static pressure energy) and (kinetic energy) of the fluid. 11. Centrifugal pump impellers can generally be classified into three types according to their structure: (closed), (semi-open), and (open). 12. The 1211 fire extinguisher is suitable for (flammable gases, liquids, and electrical fires). 13. The purpose of measuring instruments is (to obtain the true value of the quantity being measured). 14. The energy source used for pneumatic instruments is (compressed air), and the standard signal is (20-100 Kpa). 15. In automatic control systems, the larger the integral time of a regulator, the weaker its integral action is. 16. In production, it is required that the transition process of the automatic control system be an oscillatory (decaying) process. 17. The meaning of DCS is (Distributed Control System). 18. In the DCS operation screen, MAN means (Manual), and AUTO means (Automatic). 19. (Cooling) and (pressurization) are effective methods for liquefying gases. 20. The boiling point of a liquid is closely related to air pressure; as air pressure increases, the boiling point rises, and as air pressure decreases, the boiling point drops. III. True or False Questions 1. As long as the flammable substance reaches its lower explosive limit, an explosion will occur upon contact with an open flame. (Incorrect) 2. When the concentration of flammable substances in the air is above the upper explosive limit, no explosion will occur, but combustion is possible. ( True ) 3. Static electricity can cause explosions, fires, and personal injuries. (Yes) 4. To enter the equipment tank or other equipment for maintenance, a hot work permit must be obtained. (Wrong) 5. When the skin is in contact with acids or alkalis, it should be washed immediately with clean water. ( True ) 6. The lower the ignition point, the easier it is to catch fire. (Yes) 7. Closed-type safety valves are suitable for environments with flammable, explosive, toxic, or corrosive media. (True) 8. When a device explodes, new substances are necessarily produced. (Incorrect) 9. When a reversible reaction reaches an equilibrium state, the reaction has actually stopped. (Incorrect) 10. The higher the precision value of a measuring instrument, the greater its accuracy. (Incorrect) 11. Cavitation in pumps occurs mostly at low flow rates, whereas surge occurs at high flow rates, the opposite of this. (Wrong) 12. The more decimal places there are in the reading of a measuring instrument, the more accurate the measurement. (Wrong) 13. For an electric diaphragm control valve, if the valve stem is at 50% of its full travel, the flow rate through the valve is also 50% of its maximum value. (Wrong) 14. The minimum flow rate that can be controlled by a control valve and the leakage rate of the same valve are not the same concept. Answer: Yes. 15. A secondary meter refers to a meter used for recording, indicating, alarming, etc. ( True ) 16. When two centrifugal pumps are used in series, the head produced is equal to the sum of the heads produced by each pump when used alone. (Incorrect) 23. The larger the heat transfer area of a heat exchanger, the more heat is transferred. ( True ) 17. In a connected fluid at rest of the same type, the pressure at points on the same horizontal level is equal, regardless of the shape of the container. (True) 18. Since the temperature drops as a fluid evaporates, it must absorb heat from the surrounding objects; therefore, the evaporation of liquids has a cooling effect. (True) 19. The higher the viscosity of the liquid pumped by the pump, the lower its head and flow rate will be, while its efficiency and shaft power increase. (Wrong) 20. During major maintenance, the tower (or tank) can be handed over for maintenance once the analysis of its organic content shows satisfactory results. (Wrong) 21. Centrifugal pumps have three lubrication points: the mechanical seal, the bearing shaft, and the coupling. (Right) 22. Safety valves should be installed as close as possible to the equipment or pipelines that need protection. (True) 23. The boiling point of a fluid is related to atmospheric pressure; as the pressure increases, the boiling point rises. (Yes) IV. Term Explanations 1. What is pH value? The H value is the negative logarithm of the hydrogen ion concentration [H+] in the solution, that is, pH = -lg[H+]. 2. What is saturated steam? What is superheated steam? What is superheat? Answer: At a certain pressure, when water is heated to boiling point, the saturated water begins to vaporize, and the water gradually turns into steam. At this point, the temperature of the steam equals the saturation temperature; steam in this state is known as saturated steam. If saturated steam is continued to be heated, its temperature will rise above the saturation temperature at that pressure. Steam with a temperature higher than the saturation temperature is called superheated steam, and the amount by which its temperature exceeds the saturation temperature is known as the superheat. 3. What is cooling? What is condensation? What is the difference between the two? Answer: Cooling is the process of reducing the temperature of a substance, while condensation involves cooling a gas into a liquid or a solid into another solid, with no change in temperature during this process. The difference between the two is that cooling involves a change in temperature but no phase change, whereas condensation involves a phase change but no change in temperature. 4. What is critical pressure? Answer: The gas and liquid phases of a substance are in equilibrium, and the density of the gas phase is equal to that of the liquid phase. The gas-liquid interface disappears, and the state at this point is called the critical state. The pressure at the critical state is called the critical pressure of that substance. 5. What is mist entrainment? What harm does it cause to the operation? Answer: As the gas velocity increases, the phenomenon in which mist droplets are carried to the upper tray is called mist entrainment. If the amount of mist entrained from the lower trays to the upper trays is 10 percent, the operation of the tower becomes abnormal, with the result being an increase in the concentration of heavy components at the top of the tower and an increase in tower pressure. 6. What is operational flexibility? Answer: The range from the maximum allowable load to the minimum allowable load is as follows: the lower limit of the distillation column’s load is set such that the amount of mist carried by the rising steam does not exceed 10% of the steam flow rate, while the upper limit is set such that the amount of liquid leaking from the column does not exceed 10% of the liquid flow rate. 7. What is the mass transfer process? Answer: The process by which matter moves from one phase to another through diffusion. 8. What is distillation? Answer: The liquid mixture is partially vaporized multiple times, while the resulting steam is partially condensed multiple times, in order to achieve complete separation of the mixture. Based on this principle, the operation in mass transfer equipment that involves direct mass transfer to separate the components into those with the desired purity is known as distillation. 9. What is the reflux ratio? Answer: The ratio of the reflux volume to the amount of product removed is called the reflux ratio. R = L (reflux volume per unit time) / P (amount of material removed from the top of the tower per unit time). 10. What is full reflux? Answer: In distillation operations, stopping the removal of material from the top of the tower and returning all of the condensate from there back into the tower is known as full reflux. 11. What is tray efficiency? Answer: The ratio of the actual number of plates to the theoretical number of plates is called the plate efficiency. 12. What is a chemical explosion? Answer: When a substance undergoes an extremely rapid chemical reaction, resulting in an explosion caused by high temperature and pressure, it is called a chemical explosion. Before and after a chemical explosion, the properties and composition of the substances undergo fundamental changes. V. Essay Questions 1. What are the hazards of static electricity? Answer: a. It can cause explosions and fires ； b. Can cause physical injury ； c. Static electricity hinders production. 2. What is saturated steam? What is superheated steam? What is superheat? Answer: At a certain pressure, when water is heated to boiling point, the saturated water begins to vaporize, and the water gradually turns into steam. At this point, the temperature of the steam equals the saturation temperature; steam in this state is known as saturated steam. If saturated steam is continued to be heated, its temperature will rise above the saturation temperature at that pressure. Steam with a temperature higher than the saturation temperature is called superheated steam, and the amount by which its temperature exceeds the saturation temperature is known as the superheat. 3. Briefly describe the working principle of a centrifugal pump? Answer: A centrifugal pump is a machine that uses the centrifugal force generated by the high-speed rotation of an impeller to transport liquids. When the electric motor drives the impeller to rotate at high speed, the liquid at the center of the impeller is flung outward due to centrifugal force, thereby gaining energy and being discharged through the pump’s outlet pipe. After the liquid at the center of the impeller is pushed toward the outer edge of the impeller by centrifugal force, a low-pressure area is created there; fluid is then drawn into the center of the impeller through the pump’s inlet pipe. As the impeller keeps rotating, the liquid continues to be drawn in and discharged. 4. Can the outlet valve of a centrifugal pump be closed for an extended period of time while it is in operation? Answer: While a centrifugal pump is running, the outlet valve can be closed for a short time, but the closure duration should not be too long. If it remains closed for too long, the pressure of the liquid inside the pump increases, and the liquid will heat up, vaporize, and generate shock forces that can damage the impeller, the pump casing, or the shaft seal mechanism. 5. How to prevent cavitation in centrifugal pumps? Answer: 1. The installation height of the pump must not exceed the allowable suction height. 2. When the liquid flow rate and resistance in the suction pipeline are too high, the installation height should be reduced. 6. Strictly control the material temperature. 7. What are the methods for adjusting the flow rate of a centrifugal pump? Answer: Flow regulation in centrifugal pumps is achieved by altering the pump’s performance curve and the pipeline’s performance curve. 1. Method of changing the pump’s performance curve: a. Change the pump’s speed. b. Cut the outer circumference of the impeller ； Change the impeller diameter. 2. Change the pipeline characteristic curve ； The most common method is to adjust the opening degree of the centrifugal pump outlet valve. When the valve is closed, the local resistance in the pipeline increases, the characteristic curve of the pipeline becomes steeper, the operating point shifts to the left, and the flow rate decreases. 8. What is the function of a steam trap? Answer: The function of a steam trap is to prevent steam from passing through while allowing condensate to be discharged, thereby performing vapor-liquid separation and ensuring that the steam pipes in operation are free of water. 9. What are the types of shaft seals for rotating shafts? What are their respective features? Answer: There are packing seals and mechanical seals. Packing seals have the advantages of easy installation and maintenance, as well as low cost. However, its sealing performance is not very good. Mechanical seals have advantages such as good sealing performance and low likelihood of leakage, but they require high precision in installation and are expensive. 10. How to prevent freeze damage to heat exchangers in winter? Answer: 1. All cooling water heat exchangers must be supplied with cooling water regardless of whether they are in use or not; the supply must not be interrupted. The upper and lower bypass valves are slightly open. 2. A small amount of steam is supplied to all unused steam heaters, with the condensate being continuously drained via drain lines. 3. For heat exchangers that are not used for a long time, the medium inside them should be emptied. 11. What are the safety accessories of pressure vessels? What to do after a safety valve activates? Answer: Pressure vessels are equipped with the following safety accessories: safety valves, rupture discs, pressure gauges, level gauges, thermometers, etc. After a safety valve activates, it is necessary to reset the pressure (either online or offline). If manual shutdown is required, approval procedures must be followed and preventive measures taken before proceeding. 12. How should a heat exchanger be put into operation? Why? Answer: When starting up, the cold flow should be turned on first, followed by the hot flow; when shutting down, the order is reversed. The purpose is to gradually increase the temperature of the equipment, preventing it from breaking due to heat accumulation or cooling, which could lead to leaks. 13. Briefly describe the heat transfer process between the hot and cold fluids in a partitioned heat exchanger. Answer: The shell-and-tube heat exchanger is a commonly used heat exchange device in chemical production. In such a heat exchanger, the hot and cold fluids are separated by a solid wall; heat is transferred from the fluids first through convection to one side of the tube wall, then through conduction to the other side of the tube wall, and finally again through convection to the cold fluid. 14. What are the four sealing points of a pump mechanical seal? Answer: 1. Between the pump body and the gland. 2. Between the static ring and the gland. 3. Between the rotating ring and the stationary ring. 4. Between the moving ring and the shaft or shaft sleeve. 15. What are the reasons for overheating of the pump’s bearings and motor? Answer: 1) The pump shaft and the motor shaft are not aligned. 2) High motor load. 3) There is too much or too little oil in the tank. 4) The motor will not operate if one phase is missing. 5) Degraded lubricating oil. 6) The motor generates heat on its own. 7) The bearing is not properly assembled. 16. What are the causes of noise or vibration inside the pump? Answer: 1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) The rotating part is unbalanced. 5) The foundation screws are loose. 17. What are the normal inspection items for operating machine pumps? Answer: (1) Outlet pressure. (2) Bearing temperature, motor temperature, pump casing temperature. (3) Leakage: Mechanical seal leakage and oil seal leakage. (4) Is the sound normal? (5) Mechanical vibration. (6) Whether the lubrication performance is good. (7) Are the jacket cooling water and seal flushing fluid unobstructed? (8) If there is an ammeter, check as well the current reading. 18. What conditions must be met at the site where welding work will take place in order to obtain a welding permit? Answer: 1. When performing hot work outside equipment and containers, the combustible material content in the space surrounding them must be below 0.2% ； 2. When performing hot work inside equipment and containers, the combustible material content within them must be below 0.1%, and the oxygen level must be above 18% ； 3. All sources of combustible materials must be eliminated, and fire prevention measures are in place at the site ； 19. What is a sensitive plate? Answer: In the plate-by-plate calculation of a distillation column, it is often found that the composition of a certain plate varies significantly compared to that of adjacent plates, resulting in large temperature changes as well. When operating conditions change, this plate experiences the most significant temperature changes; hence, it is called a sensitive plate. 20. How to deal with flooding in distillation operations? Answer: When flooding occurs during distillation operations, normal operation is disrupted; it is necessary to promptly analyze the causes of flooding and make decisions on how to address it. If it is a equipment issue, stop the operation immediately for maintenance; if it is caused by improper operation and an increase in the temperature of the reactor, then reduce or stop the feed rate, lower the reactor temperature slightly, cease distillation at the top of the tower, and switch to full reflux mode so that the heavier components carried to the top of the tower can gradually be brought back down. If stopping the feed is not allowed due to production requirements, the output rate can be increased; once the problem of flooding is resolved, normal operation can be resumed. This method does not guarantee consistent quality, so it is generally not used. 21. What are the causes of flooding? Answer: The cause of flooding is mainly due to the excessive speed of the steam rising inside the tower, which exceeds the maximum allowable speed. Additionally, in distillation operations, a high liquid load often occurs, causing the liquid level in the overflow pipe to rise gradually until the liquids on the upper and lower trays become connected, disrupting the normal operation of the tower and leading to flooding as well. 22. What impact does mist entrainment have on distillation? Answer: During the mass transfer process, excessive mist entrainment can carry heavy components that should not reach the top of the tower into the product, thereby reducing product quality. It also decreases the concentration difference during mass transfer, leading to a decline in the efficiency of the tower plates. Generally, an allowable level of mist entrainment is 10%. 23. What are the different forms of feed in a distillation tower? Answer: There are five types of feed: cold feed/bubble point feed/gas-liquid mixed feed/saturated feed, and superheated feed. 24. What impact does the amount of feed have on distillation operations? An increase in the feed volume leads to an increased upward velocity of the vapor. When this velocity approaches the flooding velocity, mass transfer is most efficient. If the vapor velocity exceeds the flooding velocity, severe mist entrainment occurs, disrupting the normal operation of the tower. A decrease in the feed volume reduces the vapor velocity, which has a significant impact on tray towers, causing liquid leakage and reducing the efficiency of distillation. Therefore, during low-load operation, it is necessary to increase the reflux ratio appropriately to boost the vapor velocity and ensure effective mass transfer. If fluctuations in the feed volume exceed the capacity of the overhead condenser and the bottom reboiler, not only does the vapor velocity change, but the temperatures at the top and bottom of the tower also change, altering the gas-liquid equilibrium on the tray plates. This results in changes in the composition of the fractions at the top and bottom of the tower, leading to substandard product quality or increased material losses. It is therefore important to maintain stable feed levels. 25. Why is preheating necessary before putting a reboiler into use? Answer: Remove the non-condensable gases from the reboiler to avoid affecting the heat transfer area ； If metal is suddenly exposed to high temperatures, it is easy for the arrangement of its internal structure to be disrupted, which affects its mechanical properties and leads to creep; in severe cases, this can cause the metal to break, thereby impacting production ； Prevent water hammer. 26. What are the reasons why the temperature in the reactor does not rise during distillation operations? Answer: 1. The trap in the heating system is malfunctioning; the valve for circulating liquid water is not open, steam condensate is not drained, and water is present in the material. 2. The design of the equipment is unreasonable, resulting in obstruction to the circulation of liquid in the reactor. 3. Improper operation, such as heating too late or adding too much feed, can also cause coking or blockages within the tubes. 4. The composition of the liquid in the reactor is too heavy, and the available heating agent is not sufficient to raise its temperature to the bubble point, thereby preventing smooth circulation of the liquid. 5. The pressure of steam has decreased. 27. How is the reflux ratio adjusted during distillation operations? Answer: 1. Reduce the amount of product taken from the top of the tower to increase the reflux ratio. 2. When a fractionator is used as the condenser at the tower top, the amount of coolant used there can be increased to boost the amount of condensate and thus raise the reflux ratio. 3. Forced reflux can also increase the reflux ratio, but care must be taken regarding evacuation. 28. What are the factors that affect distillation operations? Answer: 1 The temperature and pressure in the tower; 2 The composition and temperature of the feed material. 3 The speed at which steam rises inside the tower and the heating amount in the evaporation vessel. 4 The reflux rate; 5 The amount of cooling agent at the top of the tower; 6 The amounts taken from the top and bottom of the tower. 29. Please explain how to use a 1211 fire extinguisher Answer: Take the portable 1211 fire extinguisher to the location of the fire. Hold the upper part of the extinguisher (do not turn it upside down), firmly grasp the handle, and open the valve. The fire extinguishing agent stored under pressure in the cylinder can be discharged. The nozzle must be aimed at the source of fire, swept from side to side, and moved forward to extinguish the fire. When the hand is released, the pressure lever returns to its original position due to the spring force, the valve closes, and the spraying stops. Repeating the operation of opening the fire extinguisher valve can also be used to discharge extinguishing agent in bursts. 30. How can static electricity accidents be prevented? Answer: 1. Limit the flow rate of liquids. 2. Use electrostatic shielding. 3. Ensure proper grounding; the grounding wire helps to dissipate or eliminate accumulated charges. 4. Increase conductivity, raise air humidity, and use electrostatic additives. 5. Avoid or prevent hazardous factors in the surrounding environment, restrict or remove dangerous substances, improve ventilation conditions, and replace or fill with inert gases. VI. Calculation problems: 1. Using circulating cooling water at 20°C, 2000 kilograms per hour of a certain material is cooled from 80°C to 40°C in a heat exchanger. The temperature of the circulating cooling water at the exit of the heat exchanger is 35°C. How many tons of circulating cooling water are required per hour? The specific heat of the material is 0.4 kcal/kg°C. Answer: Solution: The reference temperature is 0°C. Let X be the amount of circulating cooling water required per hour. Using the heat balance equation: Q1 = Q2, X*1000*1*(35-20) = 2000*(80-40)*0.4. Solving for X gives X = 2.13 tons per hour. Answer: 2.13 tons of circulating cooling water are required per hour. 2. How much heat is required to heat 50 kilograms of water from 20°C to 120°C at 1 standard atmosphere? (It is known that the enthalpy of water at 20°C is 20 kilocalories per kilogram, and at 120°C it is 647 kilocalories per kilogram.) Answer: Solution: Given the enthalpy values of water at 20°C and 120°C, we have Q = m (H120 – H20) = 50×(647–20) = 3.14×104 kilocalories. 3. The liquid flow rate into a certain container is 5 tons per hour; its density is 800 kg/m³. A seamless pipe with dimensions of 108*4 mm is used for the inlet pipe. What are the volumetric flow rate, velocity, and mass flow rate within this pipe? Answer: The volumetric flow rate Qv = W/ρ = (5 t/h) / (800 kg/m³) = 0.0017 m²/s. The diameter of the pipe is d = 108 – 4*2 = 100 mm = 0.1 m. The flow velocity is V = Qv/s = 0.0017 / ((0.1/4)²) * 3.14 = 0.22 m/s. The mass flow rate is G = ρv = 0.22 * 800 = 176 (kg/m²s)

Workshop Operator Test 2 I. Multiple-choice Questions 1. Which of the following substances is an organic compound? ( ). A. CO B. H2CO3 C. C6H6 D. Na2CO3 Answer: C 2. According to 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 victim from the power source C. Immediately call the hospital 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. Exothermic B. Endothermic C. Neither endothermic nor exothermic Answer: B 8. The valve that is not suitable for regulating fluid flow and transporting materials containing particles is ( ). A. Globe valve B. Gate valve C. Ball 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-current. Answer: A 10. For containers containing toxic, flammable substances, or those that can pollute the environment, ( ) safety valves should be used. A. Fully enclosed type B. Semi-enclosed 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 tapping point 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 stable 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 ( ) 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. Double tube 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 fluids 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 rotates 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 staggered fashion; 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\" instead of 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 becoming empty suddenly. 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 level in the waste alkali is required to prevent salt crystallization? A、30% B、15% C、25% D、20%. Answer: D. 41. The definition of 0 ℃ is (D) (A) the temperature at which ice is in equilibrium with pure water under standard pressure; (B) the temperature at which ice, water, and water vapor are in equilibrium; (C) the temperature at which the vapor pressure of ice equals that of water; (D) the temperature at which water saturated with air is in equilibrium with ice under standard pressure. 42. The temperature at which a gas can be liquefied is (D) (A) above its normal boiling point; (B) below its normal boiling point; (C) above its critical temperature; (D) below its critical temperature. 43. At standard pressure, the melting point of benzene(s) is 5.5 ℃, the density of benzene(l) is 0.90 g.cm⁻³, and the density of benzene(s) is 1.0 g.cm⁻³. At 1.0×10³ kPa, the melting point of benzene is (B) (A) 5.5 ℃; (B) slightly higher than 5.5 ℃; (C) slightly lower than 5.5 ℃; (D) cannot be determined. 44. Creating a vacuum in a container allows water to boil at room temperature, and this is because – (D) (A) the vapor pressure of water increases; (B) the heat of vaporization of water decreases; (C) the temperature of water rises; (D) the reduced pressure lowers the boiling point of water. 45. Which of the following statements is correct? (B) (A) Solubility indicates the relative amounts of solute and solvent in a solution; (B) Solubility refers to the relative amounts of solute and solvent in a saturated solution; (C) The solubility of any substance in water increases as the temperature rises; (D) Changes in pressure have little effect on the solubility of any substance. 46. When a poorly volatile solute dissolves in a solvent, it will cause (B) (A) an increase in vapor pressure; (B) an increase in boiling point; (C) an increase in freezing point; (D) all of the above. 47. The required limit for the content of non-aromatic compounds in high-purity benzene products is (D). A、 <0.2% (wt) B、 <0.05% (wt) C、 <0.5% (wt) D、 <0.15% (wt) 48. The required level of toluene in high-purity benzene products is (　C　). A、 <0.2% (wt) B、 <0.05% (wt) C、 <0.1% (wt) D、 <0.15% (wt) 49. The requirement for the freezing point of high-purity benzene products is (　A　). A、 ≥5.4℃ B、 ≥5.35℃ C、 ≥5.45℃ D、 ≥5.48℃ 50. The boiling range requirement for high-purity benzene products is (　C　). A、 ≤0.5℃ B、 ≤1.5℃ C、 ≤1℃ D、 ≤2℃ 51. The density requirement for high-purity benzene products is (　C　). A. 0.87~0.88 g/cm3 (20°C) B. 0.878~0.882 g/cm3 (15°C) C. 0.878~0.882 g/cm3 (20°C) D. 0.882~0.887 g/cm3 (20°C) 52. The boiling point of benzene is (　B　)°C. A、 78 B、 80.1 C、 79 D、 81 53. The freezing point of pure benzene is (　C　)°C. A、 5.40 B、 5.48 C、 5.53 D、 5.55 54. The explosive limit range of benzene in air is (　C　) vol%. A、 1.3～10 B、 1～7.9 C、 1.3～7.9 D、 1～6.5 55. The temperature of low-pressure steam at 0.3 MPa is usually (　B　)°C. A、 100–120 B、 120–140 C、 140–160 D、 160–200 56. The purity requirement for pure nitrogen is generally above (　D　). A、 95% B、 99% C、 99.9% D、 99.99% 57. After nitrogen purging of the device, an oxygen content level of (　C　) as determined by multi-point sampling analysis is considered acceptable. A、 <0.2% B、 <0.3% C、 <0.5% D、 <0.4% 58. The correct method for performing nitrogen purging of the system is (　B　). A. Charge while releasing air. B. Stop charging when the system pressure reaches a certain value, and exhaust air from the other end of the system. C. Continue charging while exhausting air from the other end of the system once the system pressure reaches a certain value. D. Stop charging when the system pressure reaches a certain value, and exhaust air from the charging end of the system. 59. The supply voltage for ordinary motors in general devices is (　B　). A. 220 volts B. 380 volts C. 6000 volts D. 12000 volts 60. The voltage used for lighting in ordinary devices is (　A　). A. 220 volts B. 380 volts C. 6000 volts D. 12000 volts 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 entering 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 go through the relevant procedures 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: The molecular weight is 17. Nitrogen is non-toxic, but 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 relief 29: The conditions necessary for combustion are ( ), ( ), and an energy source (such as impact, friction, an open flame, etc.). ) Answer: Combustible 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 supervise 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 in contact 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. For pipelines used for transporting media at high temperatures over long distances, the best choice for thermal compensation is ( ). Answer: Expansion joint 26. DCS primarily utilizes ( ) 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 ； Convective heat transfer ； Radiative heat transfer 31: As the operating pressure increases, the concentration of heavier components in the gas phase ( ), while the concentration of lighter 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 section above the feed plate of a continuous distillation column is referred to as ( ), while the section 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 amount of heat absorbed (or released) when the temperature of 1 gram of pure water increases (or decreases) by 1℃ is called ( ). Answer: 1 card. Watts is the unit for ( ), while kilowatts-hour is the unit for ( ); 1 kilowatt hour equals ( ) degrees. Answer: Power ； work/effort ； 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 part, Lower part. 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: Prevent steam from passing through and drain the condensate. 58. Pressure vessels must be inspected regularly, which are divided into ( ), ( ) and ( ). Answer: External inspection, internal inspection, comprehensive inspection. 59. During the pickling process, the higher the temperature, the more acid is consumed. Answer: More. 60. During the pickling process, the higher the temperature, the greater the amount of acid required (　　　). Answer: 61. When cleaning pipes containing concentrated acid, it is necessary to use (　　　). Answer: Compressed air 62. At 0°C, benzene is transparent (　　　). Answer: Solid 63. The component with the highest content in crude benzene is ( ). Answer: During the acid washing process for the refining of benzene 64 and crude benzene, the main function of sulfuric acid is ( ). Answer: In catalytic 65 and crude benzene refining, benzene, toluene, xylene, etc. are separated by distillation based on their differences in ( ). Answer: The boiling point is 66; the pressure in the reactor during distillation should not exceed ( ) MPa. Answer: 0.05. 67: Distillation columns can be classified as atmospheric pressure columns, ( ), and high-pressure columns. Answer: Distillation column 68. Benzene is insoluble in (), but soluble in organic solvents such as ethanol and ether. Answer: Water. 69. Benzene is a flammable liquid; its flash point is ( ) °C. Answer: –14. 70. The boiling point of toluene is ( ) °C. Answer: 110.6. 71. The molecular formula of xylene is ( ). Answer: C8H10 72. Benzene can undergo sulfonation reaction with ( ). Answer: Concentrated sulfuric acid 73. In places where benzene is produced and used, attention should be paid to fire prevention, explosion prevention, and prevention of ( ). Answer: Poisoning. 74. Benzene mainly originates from the aromatization process in petroleum processing, or it is obtained through the purification of crude benzene in the coking industry; the latter is specifically referred to as (). Answer: The purpose of refining crude benzene is to produce products such as benzene added to crude benzene, (), and xylene. Answer: Toluene. III. True or False Questions: 1. When the concentration of flammable 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 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. ( ) 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: √ The color of high-purity benzene products (measured by the platinum-cobalt colorimetric method) is required to be 20 or less. Answer: √ 25. The appearance of high-purity benzene products is clear and transparent, with a trace amount of sediment. Answer: × 26. It is not necessary to wear a safety belt when working at heights. ( ) Answer: × 27. The flow rate of positive displacement pumps can be adjusted using the outlet valve. ( ) Answer: × 28. Safety protection equipment includes safety helmets, safety belts, safety ropes, safety nets, etc. ( ) Answer: √ 29. The phase equilibrium reached at the end of distillation is called the dry point. ( ) Answer: × 30. An explosion is a form of rapid chemical change that occurs in a substance. ( ) Answer: × 31. Gauge pressure is equal to absolute pressure minus atmospheric pressure. ( ) Answer: × 32. The higher the vapor pressure of a liquid, the less likely it is to vaporize. ( ) Answer: × 33. Lubricant creates an oil film between frictioning surfaces to prevent direct contact between them. （　　） Answer: √ 34. The mass of a substance per unit volume is called density. ( ) Answer: √ 35. If too much lubricating oil is added to the pump, it will affect its normal operation. ( ) Answer: √ 36. The set pressure of a safety valve is generally twice the operating pressure. ( ) Answer: × 37. The voltage of the safety light used for maintenance work inside the tower is 36V. ( ) Answer: × 38. A work permit is not required for work at heights. ( ) Answer: × 39. Before putting the heat exchanger into use, the air within the cold and hot fluid streams must first be removed. ( ) Answer: √ 40. The lift height is the actual height over which a pump lifts liquid from a lower position to a higher one. ( ) Answer: √ 41. Pumps that are not in use for extended periods should have their shafts rotated 180 degrees per day. ( ) Answer: √ 42. All three methods of heat transfer exist as independent processes. ( ) Answer: × 43. Any work performed at a height of more than 2 meters above the ground is considered high-altitude work. ( ) Answer: × 44. The orifice flow meter in the instrumentation system must be installed in a vertical pipe section. ( ) Answer: × 45. The simplest way to adjust the flow rate of a centrifugal pump is to adjust the degree of opening of the pump’s inlet valve. (　　) Answer: × 46. The flow rate of a pump refers to the amount of fluid that the pump can transport per unit of time, with the unit being m3/h. (　　) Answer: √ 47. Centrifugal pumps are able to transport liquids mainly due to the centrifugal force generated by the rapidly rotating impeller. (　　) Answer: √ 48. When the shaft power remains constant, the higher the head of a centrifugal pump, the lower its outlet flow rate. ( ) Answer: √ 49. In the event of a power outage, the inlet valve of the centrifugal pump should be closed first. ( ) Answer: × 50. The head of a pump refers to the height, or pressure, at which the pump can deliver the fluid; it is expressed in meters. ( ) Answer: √ 51. When two pumps are connected in parallel, their flow rate remains unchanged while the head increases. ( ) Answer: × 52. For centrifugal pumps used to transport liquids at high temperatures, it is necessary to preheat the pump to its operating temperature before starting it ( ). Answer: √ 53. The principle of water vapor fire suppression is to reduce the oxygen content in the burning area. ( ) Answer: √ 54. The simplest way to change the flow rate of a centrifugal pump is to use valves for regulation. ( ) Answer: √ 55. To prevent the medium in the pipeline from being forced back into the pump and causing it to operate in reverse in the event of an unexpected sudden stop of the centrifugal pump, a check valve must be installed at the pump’s outlet. ( ) Answer: √ 56. Crude benzene is flammable and explosive, with a flash point of 12°C. ( ) Answer: √ 57. The boiling point of benzene at standard pressure is 80.1°C. ( ) Answer: √ 58. At standard pressure, the boiling point of toluene is 110.6°C. ( ) Answer: √ 59. The benzene content in crude benzene is over 50%. ( ) Answer: √ 60. Pipelines for transporting benzene-based products must be equipped with anti-static devices. ( ) Answer: √ 61. The use of wireless communication devices is prohibited in areas where benzene-based products are manufactured. ( ) Answer: √ 62. Operators have the right to refuse orders that violate safety regulations. ( ) Answer: √ 63. The shift handover log should record the operations carried out during the shift as well as any incidents that occurred. ( ) 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 called 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 of different densities and immiscible with each other inside the container; the liquid with the higher density sinks to the bottom, while the one 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 in which a mixture is subjected to multiple cycles of partial vaporization and partial condensation to separate the solution into its purer components is called distillation. 9. What is the 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, damaging the vitality of the skin; this is known as chemical burn. 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 known 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. 19. What is the mass transfer process? Mass transfer process: In a mixed system containing two or more components, when there is a concentration gradient, one or more of these components will move from areas of high concentration to areas of low concentration; this process is known as mass transfer. 20. Condensation: refers to the process by which a substance changes from a gaseous state to a liquid state, releasing heat in the process. 21. Temperature: a physical quantity that indicates the degree of hotness or coldness of an object. 22. Density: the mass of a substance per unit volume is called density. 23. Combustion: The combustion of fuel is the oxidation process of the combustible substances in the fuel, during which light and heat are released. 24. Liquid leakage: When the gas velocity inside the tower decreases to a certain level, the kinetic energy of the gas passing through the vapor lift holes is no longer sufficient to counteract the gravity of the liquid; as a result, the liquid flows downward through these vapor lift holes. 25. Saturated vapor pressure: The pressure that exists when a pure liquid and its vapor are in equilibrium inside a closed container at a given temperature is known as the saturated vapor pressure of that substance at that temperature. 26. Full reflux: When all of the steam rising from the top of the tower condenses and returns back into the tower, this condition is referred to as full reflux. 27. Liquid flooding: This occurs during the production process when the material surges upward; it happens because the steam rising in the tower prevents the liquid from flowing downward, causing the liquid on the lower trays to rise to the upper trays and disrupting the normal operation of the tower. 28. What is lubrication? Answer: Lubrication refers to the addition of a substance with lubricating properties to the worn surfaces of an object, in order to reduce friction and thereby minimize wear. V. Short Answer Questions 1. What are the criteria for confirming that medium-pressure steam pipelines have been properly warmed up? 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 acceptable 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: It has mainly two uses: (1) To prevent freezing during normal operation in winter (pumps are usually operated in a one-in-one-backup configuration, with the backup pump being used in winter; slightly opening the bypass valves of its inlet and outlet valves as well as the check valves allows some of the fluid to flow back). (2) When the pump is shut down, this valve is opened to empty the fluid from 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 convenient ； (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 confirm 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 flanges) ; when under pressure, this gasket deforms and fills in the uneven gaps between the two sealing surfaces, thereby preventing fluid leakage and achieving sealing. 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 applied 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 criteria for the rainwater drainage system? Answer: Rainwater discharge requirements: oil