Chloroethylene Plant Test Paper

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Chloroethylene Plant: Refining Unit Exam (Set A) Name: ___________ Sections: Fill-in-the-blanks, True/False Questions, Multiple-choice Questions, Short-answer Questions Total Score: _______ Score Obtained: I. Fill-in-the-blanks (20 points) 1. The distillation off-gas condenser should be periodically defrosted to prevent __clogging of the off-gas condenser__. 2. Distillation is a process that makes use of the different __boiling points__ of substances; it involves multiple cycles of evaporation and __condensation__ at certain temperatures in order to separate various components. 3. When the level of vinyl chloride in the gas tank is too low, the compressor will be shut down via interlock to protect the tank. 4. A centrifugal pump is a device that uses the __centrifugal force__ generated by the high-speed rotation of its __impeller__ to transport liquids. 5. The coolant used in the 0℃ refrigeration system is __ethylene glycol solution__, while the refrigerant is __Freon R134a__. 6. The pressure of the return water for heating is controlled at __200__ kPa. 7. In the tank area, when the liquid level in the spherical tank rises to a certain level, an interlock mechanism is activated to shut off the __feed valve__. 8. The concentration of vinyl chloride in the production workshop should not exceed __30 mg/m3__. 9. It is prohibited to operate the shielded pump with no load/without any fluid flowing through it. 10. The equipment used for dehydration in the distillation process includes the __pre-cooler__, the separation tank, and the __drier__. II. True or False Questions (20 points) 1. The higher the density of calcium chloride solution, the lower its freezing point; therefore, the higher the density used in preparing the solution, the better. ( ) 2. Chloroethylene is in a liquid state under standard conditions. ( ) 3. Exhaust gas refers to the gases that have not been condensed by the exhaust gas condenser. ( ) 4. It is normal for alkaline liquid to be discharged from the bottom of the chloroethylene storage tank. ( ) 5. Shield pumps can operate at idle speed, and operating at idle does not generate any work, thus saving power consumption. ( ) 6. When the liquid monomer in the pipes is heated, it expands, which can lead to pipe rupture. (√) 7. The formation of polymeric substances in distillation towers has nothing to do with the influence of moisture. ( ) 8. The boiling point of vinyl chloride increases as pressure rises. ( ) 9. Vinyl chloride has very low solubility in water; therefore, the wastewater from the separator before the distillation unit can be discharged directly into the sewer system. ( ) 10. Once the vinyl chloride compressor trips, it must be restarted immediately to ensure continuous production. ( ) III. Multiple-choice questions: (20 points) 1. In the distillation process of vinyl chloride, feeding is generally carried out in (C.). A. Gas phase B. Solid phase C. Liquid phase 2. The explosion limit of vinyl chloride in air is (B.). A.2.3—8.1% B.3.6—31% (V) C.2.3—81% D.3.6—72% How should an increase in the EDC content in the 3-monomer be addressed? (A) A. Increase the discharge volume of high-boiling substances at the bottom of the high-boiling tower appropriately. B. Reduce the reflux ratio appropriately. C. Raise the temperature at the bottom of the tower appropriately. D. Check for any abnormal changes in the internal components of the tower. 4. The acetylene content in the monomer feed is high (B). A. Switch to the tank containing defective material and reduce the temperature at the bottom of the tower. B. Increase the temperature at the bottom of the tower and switch to the tank containing defective monomer. 5. The vinyl chloride compressor is a (C) type of compressor. A. Centrifugal. B. Double-cylinder piston-type. C. Twin-screw type. D. Diaphragm type. 6. When the tower pressure rises due to a disruption in the circulating water in the product condenser, it is necessary to take action immediately (B). A. Empty the contents inside the tower. B. Shut off the hot water valve and drain the hot water from the reboiler. C. Indecisive. 7. The product VC is delivered to the PVC workshop in (C.) state. A. Gaseous B. Solid C. Liquid 8. The function of the tail pipe in a shielded pump is (A). A. Cooling and exhaust B. Maintaining minimum reflux C. Preventing excessive pressure at the pump outlet 9. Vinyl chloride distillation is a change in (A.). A. Physics B. Chemistry C. Both 10. The density of vinyl chloride is greater than that of water (B). A. Large B. Small C. The same IV. Short-answer questions: (40) 1. Under what circumstances should the monomer feeding be switched to the defective monomer sphere tank? (4 points) During startup and shutdown, in the low-boiling and high-boiling towers, when there are fluctuations in pressure, temperature, and liquid level, or when there are significant changes in the pressure difference between the two towers. 2. What are the reasons why the exhaust gas condenser temperature cannot be controlled? (6 points) High content of inert gases, insufficient flow or pressure of calcium chloride brine, high temperature, and blockage in the liquid return pipe of the exhaust gas condenser. 3. If the temperature of the water delivered at 0°C is too high, what impacts does it have on the controls within the distillation unit? (5 points) A full condenser, a top condenser of the recovery tower, and an pre-machine cooler. 4. What are the sources of heat energy used for heating in the heat exchange station, and who are the heating users? (5 points) Power plant steam, heat from conversion reactions. Company heating. 5. Why is the outlet temperature of the vinyl chloride compressor controlled below 80°C? (4 points) At 600 KPa and temperatures above 80°C, vinyl chloride partially decomposes to produce hydrochloric acid, which corrodes the pipes and equipment in the distillation system. 6. How can high acetylene content in vinyl chloride monomer be adjusted? (6 points) Slightly increase the temperature at the bottom of the low-boiling tower, inform the conversion system to adjust the ratio, switch the output to the tank containing unqualified monomer, and wait 2 hours for the product tanks to be homogenized before conducting analysis. 7. Briefly describe the main steps of exhaust gas adsorption? (6 points) Adsorption, pressure reduction, reverse operation, evacuation, pressure increase, final pressure increase. 8. How many parts does a distillation tower consist of? (4 points) Reboiler, tower body, tray, top condenser, inside the tower. Last edited by wyg1004 on 2009-3-14 22:41]