I would appreciate it if someone could provide me with some questions on diesel hydrogenation in Microsoft Word format. Thank you!

I. Multiple-choice questions:
1. During dry sulfidation at 230°C, after H2S penetrates, the amount of sulfiding agent added to the reactor should be adjusted to ensure that the H2S content at the reactor outlet is within (B).
A. 0.1–0.2%
B. 0.1–0.3%
C. 0.1–0.5%
D. 0.2–0.5%

2. The effect that cannot be achieved by adjusting the bed temperature of the cracking reactor in a stepped manner and raising the outlet temperature of the cracking reactor is (C).
A. Adjusting product yield
B. Preventing the reactor from overheating
C. Preventing catalyst coking
D. Increasing the heat exchange temperature of the feed oil

3. The incorrect statement regarding the disadvantages of the two-stage hydrocracking process is (B).
A. High investment cost
B. Not suitable for processing heavy and low-quality feedstocks
C. Complex process flow
D. High operating costs

4. The form of sulfur corrosion that occurs at the elbows and tees in the inlet and outlet pipelines of the reboiler at the bottom of the distillation tower is (A).
A. Corrosion caused by high-temperature H2S
B. Corrosion caused by high-temperature H2S + water vapor
C. Hydrogen sulfide corrosion
D. Corrosion caused by low-temperature H2S + H2O

5. The maximum allowable concentration of hydrogen sulfide in the air inside the plant is (B).
A. 5 mg/m³
B. 10 mg/m³
C. 15 mg/m³
D. 20 mg/m³

6. The incorrect statement regarding the impact of Na+ on the catalyst is (D).
A. Reducing the octane number of gasoline products
B. Lowering the melting point of the catalyst structure
C. Affecting the hydrogenation activity of the catalyst
D. Affecting the cracking activity of the catalyst

7. During the catalyst removal process, which part of the catalyst is most prone to spontaneous combustion? (B)
A. Bottom of the reactor
B. Top of the reactor
C. Location where cold hydrogen is injected
D. Area around thermocouples

8. Which of the following products is not a main product of a hydrocracking unit? (C)
A. Naphtha
B. Lubricant base oil
C. Heavy aromatics
D. Middle distillate oil

9. During the dry sulfidation process, the heating rate from the initial temperature to 230°C should be controlled at (A).
A. 3°C/h
B. 4°C/h
C. 6°C/h
D. 8°C/h

10. During shutdown, why is the circulation rate of hydrogen kept at its maximum flow and pressure before the reaction system is thoroughly purged? (C)
A. To prevent catalyst coking
B. To prevent the bed from overheating
C. To remove oil from the catalyst
D. This step is not necessarily required

11. During normal operation, the excess air ratio in the heater should be maintained at (C).
A. ≤5%
B. 5–10%
C. 10–15%
D. 15–20%

12. The general range in which mixed-sulfuric acid stress corrosion occurs is (B).
A. pH of 3–4
B. pH < 5
C. pH of 5–7
D. pH < 7

13. In a hydrocracking unit using a combined oil process, when the pressure relief system operates at 7 bar/min, which of the following equipment will not shut down automatically? (C)
A. Fresh feed pump
B. Fresh hydrogen compressor
C. Circulating hydrogen compressor
D. Circulating hydrogen heater

14. Which hydrocracking process results in diesel products with a higher aromatic content? (A)
A. Single-stage process
B. One-stage series process
C. Two-stage process
D. One-stage reverse process

15. In a hydrocracking unit using a combined oil process, the rate at which pressure is increased in the reaction system should not exceed (B).
A. 8 bar/min
B. 15 bar/min
C. 20 bar/min
D. 25 bar/min

16. The initial temperature at the inlet of the system’s sulfidation reactor should be maintained at (B).
A. 150–175°C
B. 175–190°C
C. 190–230°C
D. 230–290°C

17. During shutdown, the cooling rate of the reactor must not exceed (C).
A. 8°C/h
B. 15°C/h
C. 25°C/h
D. 30°C/h

18. Unconverted oil from hydrocracking cannot be used as raw material for which of the following? (D)
A. Ethylene production
B. Catalytic cracking
C. Lubricant production
D. Continuous reforming

19. If the H2S concentration in the circulating hydrogen reaches 10%, which of the following will theoretically not be significantly affected? (A)
A. The cracking activity of the cracking agent
B. The desulfurization activity of the refining agent
C. The aromatic saturation capacity of the refining agent
D. The operational life of the catalyst

20. Which of the following is not a condition that must be met before closing the pressure relief valve after starting venting at 7 bar/min? (B)
A. The circulating hydrogen compressor is operating normally
B. The reactor inlet temperature has dropped to 150°C
C. The reaction temperature is 30°C lower than normal
D. The pressure in the reaction system has dropped to 0.05 MPa

21. Which of the following measures does not help prevent FeS from depositing at the top of the refining reactor? (B)
A. Sealing the feed tank with nitrogen
B. Improving the precision of the feed filter element
C. Controlling the distillation operations in the upstream vacuum distillation unit
D. Installing a deironing agent at the top of the refining reactor

22. The sign that catalyst sulfidation is complete is (A). A. The H2S concentration at the inlet and outlet of the reactor is the same. B. The temperature rise in the reactor does not exceed 3°C. C. A small amount of water is generated as a by-product. D. The temperature at the reactor inlet reaches 370°C. 23. A relief valve is a special type of pneumatic valve; it has two characteristics: first, it can only be in either fully open or fully closed state, and second, (D). A. The switch is easy to use. B. It shuts off tightly. C. It cannot be opened after being shut off. D. The switch operates quickly. 24. As the operating cycle of the hydrocracking catalyst lengthens, its activity gradually decreases; in order to meet the desired requirements regarding product quality and yield, this is often compensated for by gradually increasing (B). A. Reaction pressure B. Reaction temperature C. Hydrogen partial pressure D. Amount of fresh hydrogen supplied to the system. 25. Hydrogenation catalyst regeneration is the process of restoring the catalyst’s activity through (D). A. Burning off nitrogen adsorbed on the catalyst B. Burning off unnecessary heavy metals adsorbed on the catalyst C. Burning off sulfur adsorbed on the catalyst D. Burning off carbon deposits on the catalyst 26. The function of the diffuser at the reactor inlet is to prevent the high-speed oil-gas mixture from hitting (A) directly, and it also plays a role in distributing the vapor and liquid phases. A. Inlet distribution tray B. Catalyst level C. Ceramic balls at the top of the bed D. Top protective agent 27. During hydrocracking, increasing the reaction temperature accelerates the cracking reaction; therefore, as the reaction temperature rises, the proportion of low-boiling-point components in the reaction products increases, and the content of (C) also increases. A. Naphthenes B. Isomer/normal alkane ratio C. Alkanes D. Aromatics 28. The feed flow rates FIC1001 and FFIC1002 in the simulation system’s hydrocracking unit are controlled using proportional control; FIC1001 is under automatic control, while FFIC1002 is adjusted proportionally based on FIC1001, with the adjustment ratio determined according to (C). A、10:1 B、8:1 C、9:1 D、8:2 29、The function of the jet fuel stripping tower is (D). A. Ensure that the dry point of aviation fuel is within acceptable limits. B. Ensure that the initial boiling point of aviation fuel is satisfactory. C. Ensure that the freezing point of aviation fuel is appropriate. D. Ensure that the flash point of aviation fuel meets the required standards. The purpose of feeding the gas from tower C201 in the butane tower into the absorption/desorption tower is (A). A. Remove light hydrocarbons B. Remove H2S C. Remove impurities D. Remove water from the gas 31. The function of the thermal high-pressure separator D103 is (B). A. Perform three-phase separation of gas, oil, and water. B. Perform two-phase separation of gas and oil. C. Perform two-phase separation of oil and water. D. Perform two-phase separation of gas and water. 32. The correct expression for space velocity is (A). A. Volume of feed per hour B. Volume of catalyst; Volume of catalyst; Volume of feed per hour C. Volume of feed per hour D. Volume of the reactor; Volume of the reactor; Volume of feed per hour 33. The catalyst can accelerate the rate of chemical reactions, and its chemical properties remain unchanged before and after the reaction (A). A. Basically no change B. Change occurs C. Most remain unchanged D. A small portion remains unchanged 34. Increase the hydrogen-to-oil ratio in the hydrocracking reaction (B). A. Unfavorable for the hydrogenation reaction B. Favorable for the removal of reaction heat C. Accelerates catalyst coking D. Prolongs the contact time between the feed oil and the catalyst 35. The purpose of injecting water before high-pressure air cooling is (D). A. Lower the temperature of the reaction stream. B. Wash away H2S. C. Reduce corrosion in the air cooler. D. Wash away the salts formed as a result of the reaction. 36. If the excess air volume in the heating furnace is too low, and there isn’t enough air supply, the fuel cannot burn fully, resulting in reduced efficiency of the heating furnace (D). A. Increase B. No change C. Variable C. Decrease 37. The reason for tempering in a heating furnace is (D). A. Excessive suction force B. Excessive amount of air entering C. Blockage of the gas burner nozzle D. The combustion rate exceeds the adjustable range. 38. In distillation operations, the parameters that serve as operational indicators consist of qualitative values and quantitative values; the quantitative values are (A). A. Flow rate B. Pressure C. Temperature 39. With all other conditions remaining unchanged, if the pressure in the distillation column increases, the product at the distillation outlet (B). A. Become heavier B. Become lighter C. Remain unchanged 40. When the top reflux flow rate in a fractionating tower increases, the top temperature decreases, and the internal reflux ( A ). A. Increase accordingly B. Decrease accordingly C. Remain unchanged 41. As the bottom temperature of the distillation column rises, the vaporized components (C) increase, and the gas velocity increases. A. Lighter B. Unchanged C. Heavier 42. In the oil produced by hydrocracking, (A). A. High content of heteroalkanes B. High content of olefins C. Primarily straight-chain alkanes D. Low aromatic content. 43. The purpose of pre-sulfurization of hydrocracking catalysts is (A). A. Increase the hydrogenation activity of the catalyst B. Decrease the activity of the catalyst C. Increase the strength of the catalyst D. Increase the pore volume of the catalyst 44. If the sulfur content in the feedstock for hydrocracking increases, then the average temperature of the reaction (C) A. Decreases B. Remains unchanged C. Increases 45. The head pressure of a centrifugal pump is related to its rotational speed (D) A. In direct proportion B. In inverse proportion to the square of the speed C. In inverse proportion D. In direct proportion to the square of the speed 46. Activated molecules possess (A), which is referred to as reaction activation energy. The difference between the lowest energy and the average energy of the molecules The sum of the lowest energy and the average energy of the molecules The difference between the highest energy and the lowest energy of the molecules The sum of the highest energy and the lowest energy of the molecules II. True or False questions: 1. When the pressure in a reaction system is increased, under certain special circumstances it is possible to allow gases to pass through the reactor in a direction that is not the normal gas flow direction. (×) 2. All equipment must be purged with inert gas or steam before hydrocarbon feedstocks are introduced during startup. (√) 3. After steam purging of the fresh feedstock buffer tank during startup, all of its outlets should be closed promptly to prevent air from entering. (×) 4. The acceptable standard for introducing nitrogen to displace air in the hydrogen supply system and reaction system is an oxygen content in the system of <0.05%. (×) 5. If impure removal of inorganic sulfur in the distillation system leads to product corrosion that does not meet the requirements, this issue can be resolved by storing the product for a few days. (√) 6. Precious metal catalysts are generally not used in the single-stage process of hydrocracking. (√) 7. Polyoxysulfate stress corrosion most commonly occurs in equipment made of stainless steel or high-alloy materials. (√) 8. Unacceptable copper corrosion of liquid hydrocarbons in hydrocracking units is sometimes due to alkaline corrosion. (√) 9. When the compressor stops operating, nitrogen should be introduced as soon as possible to cool it down. (×) 10. During the initial airtightness testing, if there is insufficient nitrogen in the system, purified air can be used to increase pressure for airtightness testing. (×) 11. Heat exchangers generally tend to scale more when the plant is operating at low load than when it is operating at high load. (√) 12. During the shutdown process, flushing with hydrogen can be carried out only after the temperature of the high-temperature oil pipeline drops below 300°C. (×) 13. Elemental sulfur is more corrosive than hydrogen sulfide. (√) 14. The more thorough the carbon burning during catalyst regeneration, the better the quality of catalyst regeneration. (×) 15. It is not necessary to passivate the hydrocracking catalyst before putting it into operation. (√) 16. At an inlet temperature of 345°C in the reactor during the final stage of dry sulfiding, the H2S concentration in the circulating hydrogen should be maintained at 0.5–1%. (×) 17. Water should be added to the system 2 hours before feeding it. (×) 18. Surface decarburization is caused by hydrogen atoms entering the metal. (√) 19. The hydrogen sulfide corrosion product FeS can act as a protective film to prevent the corrosion reaction from continuing. (×) 20. The elbow area suffers much more severe erosion corrosion compared to straight pipes, but the degree of sulfur corrosion is roughly the same. (×) 21. There is no essential difference between a multi-stage sequential process and a single-stage process; the only difference lies in the control methods, which are determined by the properties of the catalysts used. (√) 22. The hydrodesulfurization reaction proceeds more easily than the denitration reaction; therefore, when the nitrogen content in the refined oil resulting from this reaction is less than 10 ppm, the distillation products contain virtually no sulfur. (×) 23. The use of amorphous catalysts can appropriately reduce the formation of polycyclic aromatic hydrocarbons. (√) 24. Before starting up with low-nitrogen oil, the temperature at the highest point of the reactor must not exceed 250°C. (×) 25. In accordance with the requirements of the combined oil process, when the reaction temperature exceeds the normal value by 28°C, the feed pump should be stopped and the feed supply should be interrupted. (×) 26. Split control refers to the situation where the output signal of a controller is sent to two or more control valves, with each valve operating within a certain range of the controller’s output signal. (√) 27. The purpose of sulfiding hydrocracking catalysts is to improve the hydrogenation activity of the catalysts. 　　　　　(√) 28. During the sulfidation of the catalyst, the reactor inlet temperature and the rate of temperature increase must be strictly controlled solely to prevent the reactor bed from overheating. 　　　　　　　　　　　　　　　　　　　　　　　 (×) 29. The so-called air-operated valve is a control valve in which the air pressure applied to the diaphragm of the control valve is inversely proportional to the opening degree of the valve. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　(×) 30. The reaction temperature in hydrocracking is limited by the selectivity of the catalyst and its maximum operating temperature. 　 (×) 31. The function of the cold hydrogen tank is to thoroughly mix the reaction stream from the previous bed layer with cold hydrogen gas in order to cool it down. (√) 32. The cold low-temperature stage serves only to further separate oil from water. 　　　　　　　　　　　　　　　(×) 33. As the purity of the recycled hydrogen decreases, in order to maintain a constant one-pass conversion rate, the temperature of the cracking reaction needs to be reduced appropriately. (×) 34. In the simulated hydrocracking unit, a pressure control scheme with high and low pressure selection is adopted to stabilize the pressure of the reaction system and ensure the compression ratio of the hydrogen compressor. 　　　　　　　　　　　　　　　　　　　　(√) 35. The purpose of cold oil transportation is to gain further familiarity with the operations through oil transfer, to dehydrate the system, and to calibrate the instruments. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　(√) 36. After sulfidation, hydrocracking catalysts containing molecular sieves exhibit high hydrocracking activity. Since the hydrocracking reaction is a highly exothermic reaction, it is necessary to deactivate the catalyst before feeding it with oil in order to prevent the reaction from becoming too intense. 　　　　　　　　　　　　　　　　　　　　　　　　　　(√) 37. When ammonia is adsorbed by a catalyst, it can effectively suppress the catalyst’s activity; therefore, ammonia can cause permanent poisoning of the catalyst. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　(×) 38. The operating principle for the reactions in a hydrocracking unit is to increase the flow rate first, then raise the temperature; and to lower the temperature first, then reduce the flow rate. 　(√) 39. The principle behind using absorption to separate gas mixtures is to take advantage of the differences in the solubility of various components in a solvent, thereby achieving gas separation; the greater these differences, the better the selectivity of absorption. 　　　　　　(√) 40. In the operation of gas desulfurization, as the total pressure increases, both the partial pressure of the solute gas and its solubility increase, which is unfavorable for absorption. 　　　　　　　　　　　　　　　　　　　　　　　　　　　(×) 41. The higher the pressure, the more favorable it is for distillation. 　　　　　　　　　　　　　　　　　　　(×) 42. For oil distillation columns, the reflux ratio is determined by the thermal balance of the column, rather than by the separation accuracy. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　(√) 43. The bottom temperature of the tower is the main indicator for determining the amount of evaporation of the material within that tower. 　　　　　　　(√) 44. The heavier the oil, the higher its auto-ignition temperature. 　　　　　　　　　　　　　　　　　　　　(×) 45. As the reaction depth increases, the liquid yield rises. 　　　　　　　　　　　　　　　　　(×) 46. When the extraction rate of the product changes, the internal reflux in the column remains unchanged. 　　　　　　　　　　　　(×) 47. The principle for starting up a shell-and-tube heat exchanger is to first turn on the hot fluid, and then the cold fluid. 　　　　　　(×) 48. The function of the circulating hydrogen compressor is to maintain the pressure in the reaction system. 　　　　　　　　　　　(×) 49. Generally, deoxygenation is easier than denitration in refining reactions. 　　　　　　　　　　　　(√) 50. Limiting the iron ion content in the raw materials is to prevent catalyst poisoning. 　　　　　　　　　　(×) III. Fill-in-the-blank questions 1. During the heating up of the equipment when the plant is brought online, thermal expansion and thermal stress can cause minor leaks at the joints between flanges and gaskets. To minimize the potential harm, the heating rate should generally not exceed 25°C per hour. 2. A series of hydrocracking units is used to address the issue of deposition of polycyclic aromatic hydrocarbons; currently, this is achieved by discharging some of the recycled oil and using a polycyclic aromatic hydrocarbon adsorption and separation system. 3. The impurity content in the fresh hydrogen used in the hydrocracking unit, particularly the Cl- content, must be monitored; if necessary, dechlorination tanks should be added, otherwise it will cause severe corrosion to the equipment and pipelines. 4. Impurity in the new hydrogen mainly affects the reaction temperature in the purification reactor; when the levels of CO and CO2 in the hydrogen are high, the deoxygenation reaction increases, resulting in more heat release and an elevation in the temperature of this reactor, which can even lead to loss of control. 5. Achieving a higher reaction conversion rate leads to an increase in reaction temperature, higher hydrogen consumption, and an accelerated deactivation rate of the catalyst. 6. When the hydrocracking and refining reactor is operating normally, the main reason for the unsatisfactory corrosion resistance of light and heavy naphtha is that the stripping tower in the distillation system fails to thoroughly strip out the H2S dissolved in the produced oil. 7. The main reasons for the decrease in the heat exchange temperature of the crude oil are too low a temperature of the crude oil entering the unit, as well as scaling on the surface of the crude oil heat exchanger, which leads to a reduction in heat exchange efficiency. 8. The one-pass process refers to the technological process in which, after fresh feed undergoes reaction conversion to a certain extent, the unconverted oil is used directly as a raw material for ethylene production, catalytic cracking, lubricants, etc. 9. It is generally advisable to keep all burners in the heating furnace lit, even during low-load operation, to ensure even heat distribution across all furnace tubes; the excess air amount should be maintained at around 10%–15%. 10. Too little excess air in the heating furnace leads to incomplete combustion, resulting in flue gases containing CO; contact with external air may cause secondary combustion. 11. In high-pressure hydrocracking, if misoperation occurs, the reaction temperature can rise above 800°C, resulting in thermal hydrocracking reactions. If the temperature rises to 870°C, the catalyst lattice will change. 12. The steps for handling accidents in emergency situations are: cooling down the heating furnace or shutting it off, reducing the feed rate or stopping feeding, and performing an emergency pressure release in the reaction system. 13. When the 7 bar/min emergency venting system is activated manually, it is necessary to ensure that the cyclohydrogen compressor is operating properly; the pressure relief valve can be closed only when the reaction temperature is at least 30°C below the normal level, or when the pressure in the reaction system drops to 0.05 Mpa. 14. The corrosion of the tube bundle in high-pressure air cooling depends mainly on the concentration of NH4HS in acidic water, the Kp value, and the inlet flow rate; to ensure an adequate water supply, 20% of the water at the injection point should remain in the liquid phase. 15. If the support mesh on the reactor bed grid leaks, the catalyst that leaks out will deposit on the distribution tray beneath the cold hydrogen tank, resulting in poor quenching efficiency and uneven distribution. 16. When the high-level liquid level indicator is malfunctioning or the glass plate level indicator provides unclear readings, to determine the high-level liquid level, one should first observe the operating condition of the recycle hydrogen compressor, and further confirm it by checking its rotation speed, the pressure difference between the inlet and outlet, as well as the changes in the liquid level in the acidic oil tank. 17. Using a cracking catalyst with good nitrogen resistance can effectively facilitate temperature matching between the refining and cracking catalysts. 18. After catalyst regeneration, excessive cleanliness of the coke will inevitably lead to the accumulation of metals on the catalyst and damage to its skeletal structure, reducing its specific surface area and affecting its performance. 19. To avoid the possibility of the formation of explosive hydrocarbon-oxygen mixtures during shutdown, the reaction system must be purged with nitrogen. Before opening the reactor, it must be cooled to below 40°C to reduce the risk of hydrocarbon-oxygen explosive mixtures and spontaneous combustion of iron sulfide. 20. The direction and limit of the absorption process depend on the equilibrium relationship between the solute in the gas and liquid phases. 21. The source of atomic hydrogen that causes hydrogen damage can be the decomposition of hydrogen gas under high temperature and pressure, or the ionic decomposition of H2S+H2O at low temperatures. 22. In hydrocracking units, the corrosion areas caused by high-temperature H2+H2S are mainly found in the hydrogenation reactor, the heat exchanger for reaction products, the heating furnace, and the process pipelines. 23. The definition of excessively high reactor bed temperature under the combined oil process is any reaction temperature that exceeds the normal value by 28°C or reaches 427°C. 24. In a hydrocracking unit, the purpose of injecting water at the inlet of the air cooler is to dissolve the ammonium salts generated during the reaction process, thereby preventing blockages in the pipes and the air cooler. 25. The activity of a catalyst is an indicator of the speed of a reaction; a catalyst with high activity implies a high space velocity and a lower reaction temperature. 26. The refining reactor primarily serves to remove sulfur, nitrogen, and oxygen. 27. During the catalyst sulfidation process, the bed temperature must not exceed 230°C before hydrogen sulfide penetrates throughout the reactor bed. 28. A so-called air control valve is one in which the air pressure applied to the diaphragm of the control valve is inversely proportional to the opening degree of the control valve; that is, the greater the air pressure, the smaller the opening degree of the control valve. 29. After being used for a period of time, due to factors such as coking and poisoning of the catalyst, it will gradually become deactivated, that is, its activity and selectivity will decrease. 30. The main advantage of external catalyst regeneration is the high rate of restoration of the catalyst’s activity. 31. The function of the cold high-pressure separator is gas-liquid separation and oil-water separation. 32. As the purity of recycled hydrogen decreases, in order to maintain a certain nitrogen removal rate, the temperature of the purification reaction must be increased accordingly. 33. An increase in the nitrogen content of the raw materials, which in turn leads to an increase in the ammonia produced, results in a decrease in the catalyst’s activity. 34. In the hydrocracking unit of the simulation system, the pressures in D101 and D202 are controlled using segmented control. 35. The temperature of the lean amine stream entering the dry gas desulfurization tower must be maintained 5~6°C higher than the temperature of the feed gas, to prevent foaming of the solvent due to the condensation of hydrocarbons in the feed gas. 36. The three doors of a heating furnace refer to the throttle, valve, and air damper, while the one plate is the flue baffle. 37. The three ways of heat transfer are conduction, convection, and radiation. 38. For a complete oil distillation column, two gradients are established along the column height; that is, the temperature decreases gradually from the bottom to the top of the column ； The light component concentration in the vapor-liquid stream increases gradually from the bottom to the top of the tower. 39. The upper part of the distillation column feed inlet is called the distillation section, while the lower part is called the stripping section. 40. The main function of the overhead reflux in an oil distillation tower is to remove heat. 41. The main operational factors affecting the hydrocracking conversion rate are pressure, temperature, space velocity, and the hydrogen-to-oil ratio. 42. When hydrogenation cracking feed containing water enters the reactor, the reactor inlet temperature fluctuates sharply and the system pressure rises. 43. An increase in the H2S concentration in the recycled hydrogen will enhance the catalyst’s activity. 44. The bottom temperature of the tower is the main indicator for measuring the amount of evaporation of the material within that tower; a higher temperature corresponds to greater evaporation. 45. At a constant temperature, as the tower pressure increases, the boiling point of the product within the tower rises, distillation becomes more difficult, and the product becomes lighter. 46. As the temperature rises, the viscosity of liquid petroleum fractions decreases, while it increases as the temperature drops. 47. The backflow rate has a significant impact on the quality and yield of the product. 48. The temperatures at various points during distillation depend mainly on the properties of the feed; in other words, the temperature decreases as the degree of cracking of the feed increases.

I. Fill-in-the-blank questions – Process-related 1. The feed to the light hydrocarbons absorption tower is: the overhead gas from the butane removal tower, the overhead gas from the ethane removal tower, and . Answer: Cold low-viscosity oil. 2. Air velocity can generally be divided into mass air velocity and two other types. Answer: Volume space velocity 3. In normal operation, the water volume added to the reaction system accounts for of the total feed volume to the reaction. Answer: 5%. For equipment categories, 4. When lubricating a centrifugal pump, it is appropriate to use the amount indicated by the oil window. Answer: 1/2—2/3 5. The grade of lubricating oil to be used in the ordinary centrifugal pump in my unit is . Answer: TSA-46 anti-rust turbine oil, raw materials and auxiliary materials. 6. The refining reactor has cold hydrogen inlets. Answer: Two. 7. The cracking reactor has cold hydrogen inlets. Answer: Four. Basic Theory 8. Hydrocracking units include: a fractionation system and a unit system. Answer: Reaction system. 9. The key to operating the distillation unit is to maintain proper balance between the device’s and heat balance. Answer: Material balance. 10. The adsorption time can increase the purity of hydrogen; when the hydrogen purity exceeds the specified value, the adsorption time should be increased. Answer: Decrease, Increase. II. Multiple-choice questions (full marks are given for the correct choice; no points are awarded for incorrect, missed, or multiple selections, and no deductions are made either). Process-related: 1. The air-operated selection of a control valve is determined by . A. The forward and reverse actions of the actuator for pneumatic diaphragm valves B. Process conditions C. The forward and reverse actions of the valve core D. The forward and reverse actions of both the actuator and the valve core Answer: B 2. What is the opening degree of the control valve when the instrument air supply is stopped? A. Zero B. Fully open C. Minimum D. Unchanged Answer: B 3. Regarding the reasons for the increase in the level of the high-pressure separator, which of the following statements is incorrect? A. Blockage of the sulfur-containing wastewater control valve B. Failure of the level indication system C. Blockage in the pipeline for transporting sulfur-containing wastewater D. Reduced water injection volume. Answer: D 4. The higher the chimney, the greater its natural ventilation capacity. A. Smaller B. Larger C. Unchanged D. None of the above Answer: B 5. During the nitrogen pressure testing for the hydrogen supply system, the bypass valves of each pressure control valve should . A. Turn off B. Turn on C. Not necessarily D. Turn on first then turn off Answer: D 6. The pressure increase rate of hydrogen in the reaction system must not exceed MPa/h. A. 0.5 B. 1.0 C. 2.8 D. 3.5 Answer: B 7. If the temperature of the reactor bed rises during catalyst sulfidation, it should . A. Increase the sulfur injection amount B. Raise the inlet temperature C. Reduce the sulfur injection amount D. Decrease the amount of circulating hydrogen Answer: C 8. From the perspective of the mechanism of chemical reactions, hydrocracking is a combination of catalytic cracking and hydrogenation reactions, and its mechanism follows that of. A. Dehydrogenation reaction B. Chain-scission reaction C. Normal carbocation reaction D. None of the above Answer: C 9. Nitrogen can be used for purging only when the system pressure is at the nitrogen pressure level. A. Greater than B. Less than C. Equal to D. Cannot be determined Answer: B 9. The purpose of hydrofining is __________. A. Remove impurities from the crude oil and convert them into substances that can be easily separated and removed. B. Remove S, N, O impurities as well as saturated and unsaturated hydrocarbons from the crude oil, thereby reducing the BMCI value. C. Produce light diesel and heavy diesel for use as feedstock in cracking processes. Answer: B. 10. Once the reaction system is ready for operation, nitrogen is introduced into it, and the reaction system is purged with nitrogen through the emission of waste hydrogen. A. Raw material buffer tank B. Outlet of the recycle hydrogen compressor C. Outlet of the feed water pump D. High-pressure heat exchanger Answer: B 11. The items to be checked before starting up the heating furnace include . A. Confirm that the manhole is closed. B. Confirm that the dampers are in good condition. C. Ensure that all flue dampers are open. D. Confirm that the explosion-proof doors are in good condition and closed. Answers: A, B, D. 12. The medium used for purging the furnace before igniting the heating furnace. A. Air B. Nitrogen C. Low-pressure steam D. Medium-pressure steam Answer: C 13. The medium used for purging the gas pipeline before ignition. A. Air B. Nitrogen C. Low-pressure steam D. Medium-pressure steam Answer: B 14. The presence of carbon monoxide in the flue gas from a heating furnace indicates that . A. Insufficient air supply B. Excessive air supply C. Gas containing oil D. Positive pressure in the furnace. Answer: A. 15. The operating pressure of the cold low-pressure separator is . A. 2.6MPa B. 3.0MPa C. 2.0MPa D. 1.2MPa Answer: A 16. If the reaction temperature remains constant while the space velocity is reduced, the reaction conversion rate . A. Decline B. Rise C. Remain unchanged D. Rise first then decline Answer: B 17. Which of the following is not a benefit of setting a high score threshold? 　 A. Improve the thermal efficiency of the unit.　　 B. Prevent the precipitation of polycyclic aromatic hydrocarbons in the oil from contaminating the cooling equipment. C. Reduce the load on the cold separation unit.　　 D. Improve the efficiency of oil-gas separation. Answer: D 18. After the catalyst becomes deactivated, during the stage of improving the quality of the feed oil, it is necessary to strictly control the content of __ in the refined oil. A. Iron B. Nitrogen C. Sulfur D. Hydrogen sulfide. Answer: B 19. The most direct indicator of the quality of catalyst packing is __. A. Radial temperature distribution at the same cross-section of the catalyst bed     B. Temperature difference within the catalyst bed     C. Temperature difference between the inlet and outlet of each layer of the catalyst     D. Temperature difference across the vertical face of the catalyst. Answer: A. 20. When the water line is not in use during winter, it is necessary to drain the pipeline at certain points. A. Lowest B. Highest C. Middle D. Both ends Answer: A 21. What is used for water injection before high-pressure air cooling in the reaction system? A. Fresh water B. Demineralized water C. Circulating water D. Deoxygenated water Answer: B 22. After the pump becomes clogged, the reading on the outlet pressure gauge is higher than the normal value. A. Small B. Large C. Unchanged D. It depends; not necessarily. Answer: A. Equipment category. 23. Before starting the sulfur injection pump, which of the following statements is correct? A. The sulfide storage tank has been filled with the sulfiding agent. B. The hydraulic chamber of the sulfur injection pump has been filled with hydraulic oil. C. Lubricating oil has been poured into the crankcase of the sulfur injection pump, and the liquid level can be seen through the sight glass. D. The flow rate adjustment range of the sulfur injection pump has been set to its maximum. Answers: A, B, C. 24. The hydrogen coming from the hydrogen production unit first enters . A. Hydrogen buffer tank B. Hydrogen filter C. Water cooler D. Pressure booster compressor Answer: A 25. Which of the following is not a major component of the hydrogen supply system? A. Buffer tank at the inlet of the new hydrogen generator B. Hot high-pressure separator C. New hydrogen generator D. Reformer Answer: B 26. During the startup of the hydrogen supply system, nitrogen is used to increase pressure. A. New hydrogen compressor B. Circulating hydrogen compressor C. External high-pressure tank D. Cannot be determined Answer: B 27. Which of the following is not a step in starting a hot oil pump? A. Inject lubricating oil into the bearing housing. B. Rotate the pump and preheat it. C. Open the cooling water valve. D. There is no need to preheat the pump. Answer: D 28. The function of scale inhibitors is to prevent scaling. A. Reactor B. Air cooling C. High-pressure heat exchanger D. Heating furnace Answer: C 29. Reasons for low lubricating oil pressure in the new hydrogen compressor. A. The oil pump inlet filter is clogged. B. The pressure difference across the filter increases. C. The lubricating oil pump is faulty. D. All of the above. Answer: D 30. To switch centrifugal pumps, it is necessary to . A. Open the outlet valve of the standby pump fully after it starts up. B. Close the outlet valve of the operating pump fully after the standby pump starts up. C. Gradually open the outlet valve of the standby pump while closing the outlet valve of the operating pump slowly. D. Close the inlet valve of the operating pump fully after the standby pump starts up. Answer: C 31. Which of the following is incorrect during the startup process of a centrifugal pump? A. Check whether the circulating cooling water is functioning properly. B. Check if there is oil in the lubricating oil reservoir. C. Open the inlet valve; after starting the pump, open the outlet valve. D. Open the outlet valve; after starting the pump, open the inlet valve. Answer: D 32. Types of sulfur injection pumps. A. Centrifugal pump B. Diaphragm metering pump C. Reciprocating pump D. Gear pump Answer: B 33. When starting the scale inhibitor pump, the stroke should be adjusted to . A. 0% B. 25% C. 50% D. 100% Answer: A 34. Steps for switching the lubricating oil filter of the new hydrogen machine. A. The spare filter is in standby mode. B. Rotate the switch handle slowly; be sure that there are no large fluctuations in oil pressure. C. Close the filter connection valve, and drain the oil from the currently inactive filter as appropriate. D. All of the above. Answer: D. 35. In the following situations, it is not necessary to switch the centrifugal pump. A. The pump inlet filter is clogged. B. The control valve is faulty. C. Overcurrent. D. Pump failure. Answer: B. 36. What are the correct requirements for rotating the standby pump? A. Once a day B. Once per shift C. 180°/shift D. 360°/shift Answer: A 37. When the pump is rotating in the wrong direction, one should contact someone to make the correction. A. Instrument technician B. Machine mechanic C. Fitter D. Electrician Answer: D 37. In 2007, the new heat exchanger for raw oil and ethylene during maintenance work was designated as A. E1026 B. E1025 C. E1027 D. E1023 Answer: A 38. At the same conversion rate, it has no impact on the product distribution. A. Hydrogen-to-oil ratio B. Reaction temperature C. Space velocity D. Reaction pressure Answer: D 39. The purpose of absorption operations is to separate . A. Homogeneous liquid mixture B. Vapor-liquid mixture C. Gas mixture D. Liquid mixture Answer: C 40. To shut down a centrifugal pump properly, one should first turn off . A. Motor B. Inlet valve C. Outlet valve D. Any of them Answer: C 41. With the reaction pressure remaining constant, the higher the purity of the recycle hydrogen, the better for the hydrogenation reaction. A. Favorable B. Unfavorable C. No impact D. Not necessarily. Answer: A. 42. The newly built furnace walls should be subjected to a certain process before use; this process is known as furnace drying. A. Drying B. Heating C. Cleaning D. Lighting a perpetual lamp Answer: A 43. Oven drying involves controlling a certain rate of temperature increase to carry out heating and drying. A. Fast B. Long time C. Slow D. Short duration Answer: C Raw materials and auxiliary materials 44. Nitrogen is used in large quantities in hydrocracking. A. Purging during shutdown              B. Nitrogen purging before maintenance of the rich absorption oil pump C. Nitrogen purging during startup             D. Nitrogen sealing of storage tanks Answer: A, C 45. During catalyst sulfidation, if hydrogen sulfide does not penetrate and the reactor temperature exceeds 230°C, then there is a problem. A. Reactor overheating　　　　　　　　　　　B. Increased methane content C. Catalyst deactivation due to metal reduction　　　　　D. Increased hydrogen sulfide content Answer: C 46. The pore diameter of the crude oil filter is generally . A. 20–25 μm B. 100–200 μm C. 1–2 μm D. 5–10 μm Answer: A 47. The injection system for hydrogen-based scale inhibitors is . A. Reaction system B. Fractionation system C. Light gas desulfurization system D. Fresh hydrogen system Answer: A 48. Catalyst is one of the important factors affecting the yield and properties of hydrocracking products, and the key factor is . A. Size of the catalyst B. Acidity and pore structure of the catalyst C. Shape of the catalyst D. Method of catalyst packing Answer: B 49. The factors that affect the cracking selectivity of a catalyst are. A. Shape and size of the catalyst　　 B. Metal and active phase of the catalyst C. Packing condition of the catalyst　　 D. Metal composition, acidity, and pore structure of the catalyst Answer: D 49. What is the type of scale inhibitor used in the hydrocracking reaction system? A. GX-03D　　 B. SH-11 C. Z-723 D. MDEA Answer: A Product quality 50. Requirements for the purity of recycled hydrogen in the reaction system. A. ≮90% B. ≮99.5% C. ≯90% D. ≯80% Answer: A III. True or False Questions – Process-related 1. The high-pressure water injection pump in my unit is a reciprocating pump. Answer: √ 2. When the space velocity remains unchanged and the properties of the feedstock stay the same, a decrease in the reaction temperature leads to a decline in the conversion rate. Answer: √ 3. The adjustment of TV1147 has no effect on the reaction temperature; it only affects the high-temperature stage of heating. Answer: × 4. Before starting the sulfur injection pump, adjust its flow rate control to the middle position. Answer: × 5. If one burner in the heating furnace goes out, it can be ignited using a neighboring burner. Answer: × 5. The upper and lower limits of the controlled variable in advanced control are set by the operator themselves. Answer: × 6. Oil skimming is required when foaming occurs in the low-pressure gas desulfurization tower. Answer: √ Equipment category. 7. Centrifugal pumps that have been out of use for a long time should be rotated periodically, mainly to prevent rusting. Answer: × 8. Classified by the number of impellers, centrifugal pumps can be divided into single-stage pumps and multi-stage pumps. Answer: √ 9. Before starting a centrifugal pump, the outlet valve of the pump must be closed tightly. Answer: √ 10. All valves in the device rotate clockwise to open and counterclockwise to close. Answer: × 11. Before starting the corrosion inhibitor pump, open the inlet and outlet fully, and set the flow rate control to its minimum value. Answer: √ 12. When shutting down a centrifugal pump, the electrical switch should be turned off first, followed by closing the inlet and outlet valves. Answer: × 13. When starting a metering pump, the pump must be turned on first, followed by the outlet valve. Answer: × Raw materials and auxiliary materials 14. The radial temperature distribution at the same cross-section of the bed reflects the quality of catalyst packing. Answer: √ Product quality. 15. Operational fluctuations in the reaction affect the residues in aviation fuel. Answer: √ IV. Explanation of terms – Process-related 1. CAT2: Answer: Refers to the average temperature of the catalyst in the cracking reactor. It refers to the weighted average of the average temperatures BAT of each catalyst bed; that is, each BAT is multiplied by the percentage of the catalyst in that bed relative to the total weight of all catalysts in the beds, and these values are then added together, with the result being the average temperature of the catalyst. 2. Hydrogen partial pressure: Answer: It is expressed as the purity of hydrogen at the reactor inlet multiplied by the total reaction pressure. Equipment category 3: Power of the pump: Answer: The work done by the pump on the liquid per unit of time is called effective power. Basic Theory 4: Full cycle: Answer: It refers to the process in hydrocracking where, after undergoing hydrogenation, the oil feedstock that has not been converted into the desired products (residual oil) is returned to the feedstock mixture, where it enters the reactor once again to participate in the hydrocracking reaction. 4. Polycyclic aromatic hydrocarbons: Answer: Aromatic hydrocarbons formed when two or more benzene rings share two adjacent carbon atoms. 5. Pressure swing adsorption: Answer: It is a cyclic process of purification through pressure-induced adsorption and regeneration through pressure-reduced desorption, which relies on the physical adsorption of gas molecules by the surface of porous solid materials (adsorbents). It takes advantage of the difference in adsorption capacity of the adsorbent for the desired components versus those that are not desired within a gas mixture under the same pressure, as well as the fact that high pressure facilitates adsorption while low pressure facilitates desorption. V. Essay Questions – Process-related 1. What does it indicate when sulfur needs to be added at the reaction station during the normal operation of my plant? What is the reason? Answer: It indicates that the H2S content in the recycled hydrogen is low, and the reason is an imbalance in the sulfur and nitrogen contents in the feedstock. 2. Under what circumstances is nitrogen with a purity of 99.9% required? Answer: 1. During catalyst sulfidation, after emergency depressurization, cool the reactor ； 2. Purge the reaction system after emergency depressurization ； 3. After emergency depressurization, the reactor was cooled to 220°C. 3. What should be noted in the equipment position V-1012 and the liquid separation reaction position for inter-stage separation tanks? Answer: 1) Changes in pressure and flow rate due to cold low scores. 2) Changes in the pressure of the low-pressure gas desulfurization tower. 4. How to determine in a timely manner whether the inlet filter of the high-pressure feed pump is clogged during normal operation? Answer: Determine by checking the pressure gauge at the inlet of the high-pressure feed pump ； When the pressure on the inlet gauge drops to 0.1 MPa, the inlet filter should be cleaned promptly. 5. Which three types of equilibrium need to be understood in distillation operations? Answer: 1) Material balance. 2) Heat balance. 3) Vapor-liquid equilibrium. 6. Why is it necessary to evacuate the reaction system and replace the air with nitrogen? Answer: Since air remains in the system after the installation or maintenance of the equipment, pure nitrogen with a purity of >99.9% (by mole) must be introduced to displace this air before hydrogen is introduced into the system. Evacuating the system first before replacing it with nitrogen helps to reduce the amount of nitrogen required. Equipment category 7: What is three-stage filtration? Answer: 1) Pour oil from the large tank into the small tank for filtering ； 2) Use a small oil drum or jug for oil drainage and filtration ； 3) Filter the fuel by pouring it from the small fuel bottle into the fueling point. 8. What are the common faults of centrifugal pumps? Answer: 1) Find some time ； 2) Tripping ； 3) Sealing leakage ； 4) Bearing overheating and seizure ； 9. What is the main function of the new hydrogen engine? Where does its raw material come from? Answer: The new hydrogen compressor is used to control the reaction pressure; it supplies hydrogen of high purity to the reaction system to meet the hydrogen demand of the reaction. The raw materials for the new hydrogen generator come from the ethylene-to-hydrogen plant and the product hydrogen from the PSA of this unit. 10. How to change the lubricating oil in a running pump? Answer: When the pump is in operation, the lubricating oil in the tank should not be emptied all at once to avoid shaft seizure; instead, the oil should be added and removed in stages. 11. What are the common types of fire extinguishers? Answer: The commonly used fire extinguishers at present include: 1) Foam fire extinguishers, 2) Carbon dioxide fire extinguishers, 3) Dry powder fire extinguishers and 1211 fire extinguishers, etc. 12. What are the three conditions for combustion? Answer: The three conditions are: 1) combustible material, 2) oxidizing agent, 3) ignition source. 13. Into how many levels is work at heights divided? Answer: 1) Level 1 high-altitude work: refers to work at a height of 2–5 meters. 2) Level 2 high-altitude work: refers to work at heights of 5–15 meters. 3) Level 3 high-altitude work: refers to work at heights of 15–30 meters. 4) Extra-high-altitude work: refers to work at heights of 30 meters or more. 14. What are the different forms of explosions? Answer: There are three types: physical explosion, chemical explosion, and nuclear explosion. 15. How to report a fire? Answer: 1) Call the fire emergency number “119” to report it, and stay calm. 2) Clearly state the location of the fire, the part where it started, the material that caught fire, and the severity of the fire. 3) Provide the contact number of the person who called the fire department, and go to the intersection to meet the fire truck if necessary. VI. Calculation Problems – Process-related 1. The feed to the hydrorefining reactor is 100 t/h, with a density of d = 0.8955. The volume of the catalyst in the hydrorefining reactor is 119.328 m3. Calculate the space velocity of the hydrorefining reactor. Solution: The formula for calculating the volume space velocity of a reactor is: SV = feed rate (m3/h) / catalyst volume in the reactor (m3). SV = (100/0.8955) / 119.328 = 0.9358 (h‑1). Answer: The volume space velocity of the reactor is 0.9358 h‑1. Equipment-related questions: 2. There is a centrifugal pump with an outlet mass flow rate of 36 t/h; the density of the fluid being transported is 0.8×103 kg/m3. Determine the outlet volume flow rate. Solution: Volumetric flow rate Q = m/ρ = (36×10³) ÷ (0.8×10³) = 45 (m³/h). Answer: The volumetric flow rate is 45 m³/h. 3. For a cylindrical pressure vessel with an inner diameter of 1 meter and a height of 3 meters, what is its volume? Solution: V = 1/4 × πd² × h = 1/4 × π × 12 × 3 = 2.35 (m³). Answer: Its volume is 2.35 m³. 4. A heat exchanger has a heat transfer area of 32 m2, a total heat transfer coefficient of 0.32×104 W/m2℃, and a temperature difference of 50℃. Calculate the heat transfer rate Q for this heat exchanger. Solution: Q = KS⊿T. Q = 0.32 × 32 × 50 × 104 = 5120 (KW). Answer: The heat transfer rate of the heat exchanger is 5120 KW. Basic knowledge: 5. A substance occupies a volume of 9 m3 and has a mass of 72 t. What is the density of this substance? Solution: ρ = mass/volume = 72,000 kg / 9 m3 = 8000 (kg/m3). Answer: The density of this substance is 8000 kg/m3. 6. Determine the molecular weight of CS2 (c=12) ； s=32) ； Solution: Molecular weight = 12 + 32×2 = 76. Answer: The molecular weight is 76. 6. A certain hydrocracking unit was in operation for 30 days in a given month; during that time, it was shut down for emergency repairs for 28 hours. Calculate the availability rate of this unit for that month. Solution: Operating rate = ×100% = ×100% = 96.11%. Answer: The operating rate of this facility this month is 96.11%. VII. Drawing Questions 1. Inlet flow diagram of P-1017A 2. Quench hydrogen flow diagram of R1001 3. Modification to the fuel gas discharge flow diagram of V-1011 4. Schematic diagram of the heating furnace temperature control principle 5. Schematic diagram of the pilot light principle for F-1001

Questions to Know and Be Able to Do in the Hydrogenation Workshop I. Multiple-choice Questions 1. The steps for putting a cascade control loop into operation (A). A. Manual first then automatic, secondary regulator first then primary regulator. B. Manual first then automatic, primary regulator first then secondary regulator. C. Automatic first then manual, secondary regulator first then primary regulator. D. Automatic first then manual, primary regulator first then secondary regulator. 2. The basic principle of distillation is to utilize the differences in (B) among the various components in the vapor and liquid phases for separation. A. Density B. Relative volatility C. Dry point D. Octane number 3. The main factor determining the loss of circulating hydrogen is (D). A. Circulating hydrogen volume B. Fresh hydrogen volume C. System pressure D. Circulating hydrogen concentration 4. The temperature indicator for the compressor motor bearings is (B). A、≯85℃ B、≯80℃ C、≯75℃ D、70℃ 5、The maximum allowable temperature for the furnace chamber of this device’s reaction furnace is generally (C). A、≯600℃ B、≯700℃ C、≯800℃ D、1000℃ 6、If the bromine value of the crude oil is high, it indicates that the crude oil contains a large amount of (A). A. Unsaturated olefins B. Aromatic hydrocarbons C. Cycloalkanes D. Alkanes 7. The purpose of drying the furnace is (C). A. To test the performance of the furnace tubes B. To check whether the burner is functioning properly C. To cause the moisture inside the furnace walls to evaporate D. To test the performance of the catalyst 8. If the instrument air supply is interrupted and one control valve opens, then this valve is (B). A. Air-open valve B. Air-close valve C. Step control valve D. Cascade control valve 9. Gas control valves are generally set to (A). A. Air-open valve B. Air-close valve C. No setting specified D. None of the above 10. The part in a hydrogenation unit where high pressure can mix with low pressure is (A) A. High-pressure liquid control section B. Low-pressure liquid control section C. Cold hydrogen flow control section D. Fractionator liquid control section 11. Regular soot blowing in a heating furnace is done for (A). A. Improve heat transfer efficiency B. Reduce flue gas resistance C. Increase exhaust gas temperature D. Environmental protection. 12. When a compressor compresses gas containing liquid, it can easily cause (B), leading to damage to the compressor. A. Excessively high pressure B. Water hammer C. Excessively high temperature D. Excessively low pressure. 13. The reasons for an increase in the system’s differential pressure are (D). A. Coking of the furnace tubes B. Increased pressure drop in the reactor bed C. Ammonium salts blocking the heat exchangers and air coolers at lower temperatures D. All of the above 14. The main factors affecting the efficiency of hydrorefining are (D). A. Reaction temperature, reaction pressure B. Space velocity, hydrogen partial pressure C. Properties of the feed oil, catalyst activity D. All of the above 15. A gas valve is a device installed on a cylinder to control the (A) flow of gas. A. Unidirectional B. Bidirectional C. Multi-directional D. None of the above 16. The type of tray used in the distillation column of a hydrogenation unit is (A) A. Floating valve type B. Bubble cap type C. Packed type D. None of these. 17. The red line marked on the surface of the pressure gauge indicates (B) A. Operating pressure B. Maximum operating pressure C. Service pressure D. None of the above. 18. In Z41H-40, the “Z” represents (B). A. Check valve B. Gate valve C. Globe valve D. One-way valve 19. When loading the catalyst, a certain amount of ceramic balls must be added; the main function of these ceramic balls is (A). A. To prevent the catalyst bed from shifting or sinking during operation. B. To delay catalyst coking. C. To filter impurities out of the oil and protect the catalyst. D. To prevent short circuits from forming within the catalyst. 20. The function of the nitrogen seal in the raw material buffer tank is (B). A. Press the crude oil into the pump inlet. B. Prevent air from entering. C. Prevent negative pressure from forming in the tank. D. Prevent the liquid level in the buffer tank from rising too high. 21. The liquid level of the lubricating oil in the lubricating oil tank should be kept within (C). A. Below ⅓. B. Below ⅓ to ½. C. Between ½ and ⅔. D. At full level. 22. Introducing superheated steam at the bottom of the tower can cause the vapor pressure of the oil product to (B). A. Increase. B. Decrease. C. Remain unchanged. D. Disappear. 23. When starting up a cooler, one should first turn on (A). A. Water B. Hot fluid C. Backwashing D. Inlet 24. When restarting a heating furnace after it has been extinguished, it is necessary to first perform (C) in order to prevent backfire explosions. A. Open the large air valves B. Open the flue dampers wide C. Purge the furnace chamber D. Light the burner directly. 25. Pumps that are not in use for extended periods should be rotated manually (B) degrees per day to prevent the shaft from bending. A、90 B、180 C、45 D、120 26、When a reciprocating pump is in operation, (A) is used to regulate the flow rate. A. Piston stroke B. Pump outlet C. Pump inlet D. Return line 27. Before starting and after stopping the compressor, (B) should be used to purge the compressor body. A. Hydrogen B. Nitrogen C. Steam D. Instrument air. 28. The “three skills” referred to in the “four understandings and three skills” are the ability to operate, the ability to maintain, and (C). A. Identify the problem ； B. Repair ； C. It will eliminate faults. D. It will affect the structure. 29. Generally, a piston compressor has 4 theoretical working processes, namely expansion, suction, and compression (B). A. Doing work B. Exhausting gas C. Intaking air D. Sliding 30. The excess air coefficient for furnaces is generally required to be (A) A. 1.1～1.25 B. 1.2～1.5 C. 1.5～2.0 D. 1.5～2.5 31. Diesel engine grades are classified based on (A). A. Freezing point B. Boiling point C. Melting point D. Solubility point 32. The higher the cetane number (A), the better the anti-knock properties of the diesel fuel. A. High B. Low C. The same D. None of the above 33. There are (C) basic ways of heat transfer. A、One B、Two C、Three D、Four 34、The storage safety of diesel is indicated by (C). A. Freezing point B. Ash content C. Flash point D. Spontaneous ignition point 35. If the dry point of gasoline is high, which of the following measures should be taken? (B) A. Increase the temperature at the top of the tower B. Decrease the temperature at the top of the tower C. Increase the steam used for stripping D. Reduce the amount of reflux. 36. The required purity of fresh hydrogen for the product quality of hydrogen production units is (C). A、≥95％ B、≥97％ C、≥99.5％ D、≥90％ 37、The acceptable standard for nitrogen purging of the device is (C). A、O2≤1％ B、O2≤1.5％ C、O2≤ 0.5％ D、O2≤ 2％ 38、Increasing the adsorption pressure has an effect on adsorption ( A ). A、favorable B、unfavorable C、no effect D、none of the above 39、The relationship between the purity of the product hydrogen and the hydrogen recovery rate is ( B ). A. The higher the purity of the product hydrogen, the higher the hydrogen recovery rate. B. The higher the purity of the product hydrogen, the lower the hydrogen recovery rate. C. There is no relationship between the purity of the product hydrogen and the hydrogen recovery rate. D. None of the above. 40. The function of valve No. 1 in the PSA adsorption tower is (D). A. Check valve B. One pressure equalizing valve C. Two and three pressure equalizing valves D. Raw material gas inlet valve II. Fill-in-the-blank questions 1. The purpose of hydrorefining is to remove impurities such as sulfur, nitrogen, oxygen, and metal contaminants from oils, as well as to saturate olefins, thereby improving the performance and stability of the oils. 2. The operational factors that affect the hydrogenation reaction process include temperature, pressure, space velocity, and hydrogen-to-oil ratio. 3. A distillation column generally consists of three sections: the distillation section, the stripping section, and the feed section. 4. The main factors affecting the distillation process are operating pressure and operating temperature. 5. A tubular heating furnace generally consists of four main parts: a convection chamber, a radiation chamber, a chimney, and a burner. 6. H2 is a colorless and odorless gas that is flammable and explosive; its explosion limit ranges from 4.1% to 74.2%. 7. The operating processes of the adsorption tower include: adsorption process, pressure equalization and reduction process, reverse desorption process, vacuum pumping process, pressure equalization and increase process, and product gas pressurization process. 8. The process parameters of pressure swing adsorption mainly include adsorption time, pressure, temperature, and processing capacity. 9. When adjusting the temperature, it is necessary to follow the principle of increasing the amount first before raising the temperature, and reducing the amount first before lowering the temperature. 10. The high-level liquid level is controlled by adjusting the flow of high-pressure oil to the low-pressure section. If the liquid level is too high, circulating hydrogen will carry liquid with it, which can cause damage to the compressor; if the liquid level is too low, high pressure can enter the low-pressure system. 11. The high-density interface level is controlled by regulating the discharge volume of sulfur-containing wastewater; a high interface level can cause the light oil phase to contain water, while a low interface level can result in the wastewater containing oil or lead to oil leakage. 12. Tube charring occurs when a certain amount of steam and unpurified air is introduced at a relatively high temperature. 13. In addition to forming a water ring, the working fluid of the vacuum pump also serves to remove the heat generated during gas compression and to seal the pump cover. 14. The recycle hydrogen compressor in the hydrorefining unit is used for pressurizing and circulating hydrogen in the reaction system, while the fresh hydrogen compressor is used to supply additional hydrogen and increase pressure in the reaction system. The desorption gas compressor is used to pressurize the desorption gas in the hydrogen production system and feed it into the gas pipeline network. 15. Before activating the heat exchanger, check first whether the vent valve is closed; when bringing it into operation, the cold stream should be turned on first, followed by the hot stream. When shutting down, try to stop the hot flow first and then the cold flow. 16. When dealing with accidents, it is necessary to ensure personal safety, equipment safety, and catalyst safety. 17. When the purification air supply is stopped, the air supply valve is controlled by the bypass line, while the air shut-off valve is controlled by the upstream and downstream valves, thereby keeping the temperatures, pressures, and liquid levels in all sections within the specified process parameters. 18 Hydrogen sulfide is a colorless gas with a distinctive odor; it is highly toxic, and the maximum allowable concentration in the air is 10 mg/m3. 19. There are three methods of extinguishing fires: isolation, smothering, and cooling. 20. The safety accessories of pressure vessels include safety valves, pressure gauges, level gauges, thermometers, vent valves, etc. Three short-answer questions: 1. What is the purpose of using softened water in the normal operation of the equipment? Answer: The purpose of injecting water is to dissolve and absorb the sulfides and ammonia formed in the oil as a result of reaction processes, thereby preventing amine salts from crystallizing and blocking the high-pressure air coolers and pipelines, and ensuring that the product meets corrosion specifications. 2. What is the role of circulating hydrogen? Answer: (1) Maintain the hydrogen partial pressure in the reaction system. (2) It removes a large amount of heat of reaction from the reactor, which helps to control the reaction temperature and ensure stable operation. (3) Promote the vaporization of the oil, ensuring a uniform mixture of oil vapor and thus enabling better distribution of the oil on the surface of the catalyst. (4) It helps to enhance the activity of the catalyst and promote the progress of the hydrogenation reaction. 3. What is the reason for pre-sulfurization of hydrogenation catalysts? Answer: The reason is to change the hydrogenation catalyst from its inactive oxidized state to its active sulfided state. 4. What are the steps to start a vacuum pump? Answer: (1) Open the bypass gate valve and start the generator set. (2) Then slowly open the outlet valve and close the bypass gate valve. (3) When there is a vacuum at the inlet, slowly open the inlet valve. 5. What should be noted when sampling H2S? Answer: H2S is a toxic gas; when sampling, it is necessary to wear a gas mask, stand in the upwind direction, and work in pairs. After sampling, it is essential to confirm that the sampling valve is closed before leaving. 6. What is reaction temperature rise? What is the general control level? Answer: Temperature rise refers to the difference between the reactor inlet temperature and the highest temperature in the bed; it is generally kept at or below 60°C. An excessive temperature rise can be controlled by lowering the reactor inlet temperature or by introducing cooling hydrogen into the bed. 7. What is the purpose of introducing steam at the bottom of the hydrogen sulfide removal vapor dome tower? Answer: By introducing a certain amount of vapor at the bottom of the tower, the total pressure inside the tower remains constant, which reduces the vapor pressure of the oil and gas. As a result, the oil boils and vaporizes at a lower temperature, or its vaporization rate increases at the same temperature. 8. What is the purpose of having multiple temperature measurement points on the upper and lower surfaces of the catalyst bed? Answer: (1) Measure the temperature difference as the fluid passes through each bed layer. (2) Reflects whether there is channeling in logistics. 9. In what areas is hydrogen consumed in hydrorefining? Answer: (1) Consumption in chemical reactions. (2) Hydrogen emission consumption to increase the circulating hydrogen concentration. (3) Hydrogen consumption in dissolution in the hydrogenation product oil. (4) Hydrogen loss due to mechanical leakage. 10. Describe the startup steps for the hydrogenation reaction section Answer: (1) Preparatory work before commencement. (2) Airtight to nitrogen. (3) Airtight to hydrogen. (4) Catalyst drying. (5) Catalyst presulfurization. (6) Feed the crude oil and adjust the operation. 11. What are the measures to increase hydrogenation depth? Answer: (1) Increase the reactor inlet temperature. (2) Increase the reaction pressure. (3) Improve the purity of recycled hydrogen. (4) Reduce the air velocity. (5) Increase the hydrogen-to-oil ratio. 12. What are the methods to increase the hydrogen-to-oil ratio? Answer: (1) Increase the new hydrogen flow rate or purity. (2) Increase the flow rate or purity of circulating hydrogen. (3) Increase system pressure. (4) Reduce the feed amount. 13. What are the reasons for the increase in catalyst bed temperature? Answer: (1) Excessive temperature at the furnace outlet; (2) Changes in the flow rate and properties of the feed oil; (3) Significant fluctuations in circulating hydrogen; (4) Interruption of fresh hydrogen supply; (5) Failures related to cold hydrogen; (6) Instrument failures. 14. What are the causes of flame flashback and what are the corrective measures? Answer: Reasons: (1) Air is present in the gas; (2) The gas contains oil; (3) The gas pressure is low; (4) The exhaust force of the chimney is insufficient. Measures: (1) Replace the gas; (2) Improve the oil removal process in the gas tank; (3) Increase the pressure in the gas tank; (4) Adjust the dampers on the air vents and flues. 15. How should an outage of the equipment be handled? Answer: (1) For emergency shutdown of F2101 and F2102, open the flue dampers and supply fire-extinguishing steam to the furnace chamber. (2) Maintain the high and low levels as well as the liquid levels and interfaces in each tank, to strictly prevent high pressure from leaking into low pressure areas. (3) Monitor the temperature rise in the reactor bed; if the temperature does not exceed the limit, dumping can be stopped to maintain pressure. If the temperature exceeds the limit, increase the rate of dumping, and introduce nitrogen as necessary to ensure continuous drainage from the system. (4) Immediately close the outlet valves of P2101, P2107, and P2109, as well as the steam injection valve at the bottom of tower C2101 and the double valves at all water injection points. (5) Open the catalytic dry gas connection valve and close the catalytic dry gas inlet valve; the PSA system maintains its pressure. (6) Close the inlet and outlet valves of each press, vent the machine body, purge with nitrogen, close the inlet and outlet valves of each pump, and reset the power switch. This post was last edited by maysee on 2009-2-27 15:14]

Organic compounds that contain only two elements, (carbon) and (hydrogen), are called hydrocarbons. The general formula for alkanes is (CnH2n+2), while the general formula for alkenes is (CnH2n). For chemical reactions that involve an increase in volume, (reducing) pressure facilitates the progress of the reaction. Catalysts can change the reaction rate by altering the (reaction pathway) and reducing the (activation energy of the reaction). The activity of a catalyst reflects its ability to accelerate reaction rates, and the level of this activity is primarily indicated by the degree of conversion of the reactants. When adjusting the lift and drop amounts, the principle of first (increasing the amount) then (increasing the temperature), and first (decreasing the temperature) then (decreasing the amount) should be followed. Among the hydrorefining reactions, the hydrorefining of (nitrides) is the most difficult, while that of (sulfides) is the easiest. The hydrogenation catalyst after sulfidization has excessively high initial activity; in order to prevent potential temperature spikes during the feed introduction process and to ensure the safety of the catalyst, the equipment, and personnel, it is necessary to carry out a (passivation) treatment on it. To control the large amount of heat generated by the hydrogenation reaction and prevent the catalyst beds from overheating, a certain amount of (cold hydrogen) must be introduced between the various beds in order to regulate the temperature of each catalyst bed. In accident handling, it is necessary to avoid (losses of life) and minimize damage to (equipment) and (catalysts), in order to prevent significant economic losses. Explosion accidents should be avoided first and foremost. Nitrogen in petroleum and its fractions exists mainly in the form of (heterocyclic aromatic compounds). The hydrocracking reaction of alkanes mainly involves (isomerization) and (cracking) reactions, with the main products being (lower-molecular-weight isomeric alkanes). Hydrocracking is essentially a combination of two reactions: (catalytic hydrogenation) and (catalytic cracking), with a reaction mechanism based on the (carbocation mechanism). The main parameters that need to be controlled for hydrocracking feedstocks include: (nitrogen content), (dry point), (residual carbon), (asphaltene), (metal content), etc. Among them, the parameters of (dry point) and (nitrogen content) are the most critical, as they affect not only the stability of the catalyst but also its activity. Multiphase catalytic reactions include four stages: (external diffusion), (internal diffusion), (adsorption), and (reaction). If the catalyst becomes deactivated during operation, this can be compensated for by (raising the reaction temperature). Among hydrocarbons, (aromatics) are the most difficult to hydrogenate, and (hydrogen pressure) has the greatest impact on their hydrogenation rate; low (hydrogen pressure) results in a higher content of (aromatics) in the product. For hydrocracking, the main properties of all liquid products are related to (aromatics). Generally, control the asphaltenes content in the raw materials (