Pentanol Process Basics Test

Thread Content

Preliminary exam for the diol process Name: Score: I. Fill-in-the-blank questions. (Please write out the full units for the data; otherwise no points will be given, totaling 20 points). 1. Generally, catalysts are most vulnerable to (overheating) and (poisoning). Catalyst poisoning can be of (physical) or (chemical) nature. The catalyst model used in our company’s lysergic acid production facility is (XNC98), with its main components being (CuO), (Al2O3), and (ZnO). The poison that poses the greatest threat to this catalyst is (sulfur); therefore, the allowable concentration of this poison before it enters the synthesis tower is less than (0.1 ppm).
2. The parameters for boiler water are as follows: CA-19007, phosphate content at (10–20), pH at (9–11), conductivity at (), and SiO2 at (). 3. The location of CA-19010 is (near the east side of V4), and the detection items include ( ). 4. In the methanol synthesis reaction, the hydrogen-to-carbon ratio should be maintained at (2–2.25), and its calculation formula is: f = (H2/CO2) / (CO + CO2) = 2.05. 5. The hydrogen pressure from the low-temperature methanol wash is 6.95 Mpa, and the temperature is -20°C. 6. The circulating gas compressor is of type 19-K1, with a power rating of 327 KW, a rotational speed of 12,500 rpm, and an inlet pressure of 6.8 Mpa. It utilizes dry gas seals and labyrinth seals. 7. Enter the following parameters: FIAL-252 (15) ； PICA-205 (6.7) ； FIC-203 (2766.4) ； FIC-101 (29411) ； TRC-305 (78.8) ； TR-211 (140) ； PDIAH-253 (20kPa) ； FRA-104 (12.6) ； FRA-205 (7.2) ； PICA-206 (0.35) ； FRCQ-301 (9.1) ； FRQ-303 (0.1) ； FRQ-204 (9.2) ； FRC-305( 31 ) ； TI-214 (20) II. Short-answer questions. (30 points) 1. How to control the reaction temperature in the synthesis tower? During the initial stage of catalyst use, the reaction temperature in the synthesis tower should be kept low, while it needs to be raised as the catalyst’s activity declines over time. The heat generated by the reaction is mainly absorbed by the BW water on the shell side, which then produces medium-pressure steam to carry away this heat; therefore, it is important to control the liquid level in the gas holder properly. 2. Why is it necessary to deactivate the catalyst? When in its reduced state, the catalyst oxidizes upon contact with air, releasing a large amount of heat; it may even catch fire, causing the catalyst to burn up and leading to safety hazards during loading and unloading. 3. What are the factors that affect the cooling effect in methanol synthesis? Reduced amount of cooling water; high temperature of the cooling water; excessive impurities in the cooling water that cause blockages in the tubes or lead to scaling, thereby reducing the heat exchange efficiency; internal leaks in the heat exchanger; failure to vent air and liquid at the time of operation also reduces heat exchange efficiency. 4. Why is it necessary to add alkali solutions and water during the methanol distillation process? Water is added mainly as an extractant to remove organic impurities from the water. Since organic acids are produced during the reaction, they can be corrosive to the equipment; therefore, alkali is added to neutralize them and reduce corrosion. 5. What precautions should be taken before starting each pump to prevent cavitation? Since methanol easily volatilizes into a gas and is prone to cavitation, it is necessary to fill the pump before starting it, then exhaust any air from it fully before turning on the pump. Once the outlet pressure reaches the specified value, the outlet valve should be opened slowly; it is strictly forbidden to reduce the pressure by closing the inlet valve, as this can lead to cavitation. 6. What signs indicate that the filter screen is clogged? The inlet pressure of the pump is low and fluctuates; as the opening of the pump’s outlet valve increases, the liquid level in the tank feeding the pump rises; the motor current decreases, and the pump’s outlet pressure falls. 7. How to put PCV-101 steam into operation? 7. What are the disadvantages of oil temperatures that are too high or too low? High oil temperature reduces viscosity, leading to poor lubrication and accelerating oil aging as well as increasing shaft temperature. Low oil temperature increases viscosity, causing friction on the bearings, resulting in bearing damage and making shaft vibration more likely. 8. What are the functions of continuous drainage and regular drainage? Regular drainage is primarily carried out to remove sludge and other deposits, which, due to gravity, tend to accumulate in the lowest parts of the water circulation system. Continuous drainage is done to prevent adverse effects caused by high levels of salts and silicon in the boiler water, and it is controlled based on the analysis results of the brine. 9. Briefly describe the process of transferring pure methanol from V11 to V12 Pure methanol exits the pure methanol heat exchanger and travels through the pipeline network to the storage tanks. It splits into two streams: one goes to V11 and the other to V12. When moving from V11 to V12, the two valves leading to V11 as well as the additional valve that feeds into V11 are closed, while the valve leading to V12 is opened. Since the capacity of tank V12 is limited, its opening degree should not be too large. When both tanks are nearly full, it is necessary to contact the dispatch team to send pure methanol to the feed stream.

III. Essay Questions (24 points)
1. Please outline the operating procedures for raising the temperature during the desulfurization process (6 points).
a. First, shut off the M-1 electric valve that controls the flow of process gas into the methanol unit. Fill the system with N80 gas for nitrogen purging; vent the gas through PIC-105 or use its drain valve for purging. Continue this process until the oxygen level drops below 0.5%. Once this condition is met, maintain pressure in the system.
b. Slowly open the electric valve that controls the flow of process gas into the methanol unit, thereby raising the temperature of the desulfurizing agent by 30–50 degrees per hour, until the temperature reaches 210 degrees. At this point, the PIC-105 valve should be opened slightly to allow gas flow, which speeds up the heating process. After maintaining this temperature for 2 hours, normal flow rates of converted gas can be accepted.
c. Keep the electric valve at its normal opening degree, allow converted gas to flow in, vent it through PIC-105, and analyze the sulfur content in the desulfurized gas. If the levels are within acceptable limits, the gas can be sent to the methanol synthesis process.
2. What problems or situations can lead to an emergency shutdown of the plant? (6 points) 1. High level alarm in S2 causes water to enter the desulfurization tower, leading to the pulverization of the desulfurizing agent; an emergency shutdown is required. 2. Both gasification furnaces in the gasification unit shut down, which triggers the sequential shutdown of FCV101 and K1. 3. The boilers run out of water; both boiler feed pumps fail to start, and it becomes impossible to remove the heat generated by the reactions, so a shutdown is necessary. 4. The synthesis tower overheats; the 5s3 high-level alarm is triggered, water enters the compressor cylinder, and K1 shuts down…. 3. Please describe the primary interlock actions that occur when the compressors or gasification furnaces in the methanol synthesis unit shut down (6 points) When K1 trips, it causes the M-1 electric valve to close automatically, thereby stopping the feed process. When the gasifier trips, it triggers the shutdown of FCV-101, and at the same time the compressor also shuts down automatically. 4. Briefly describe the starting up and pump switching process of the boiler feed water pump (6 points) Before starting the BW pump, it is necessary to ensure that all components and valves are in good condition. First, perform pump warming: close the inlet drain valve and the outlet valve. Slowly open the BW water inlet valve to start pumping; open the first stage of the warm-up valve to 2 positions and the second stage fully, and open the first stage of the minimum flow valve to 2 positions and the second stage fully. Carry out pump warming, and also open the drain and vent valves on the outlet pipeline. Once water is discharged, close the vent valve. After pump warming is complete, contact the electrical department to supply power to the pump. At this point, close the warm-up valve, turn the pump manually, and then start it. Check the outlet pressure; once it reaches the specified value, gradually open the outlet valve and vent again to prevent cavitation. Finally, open the outlet valve fully and close the minimum flow valve. During operation, continuously monitor the temperature, vibration, and operating current. When switching to a standby pump, ensure that it has been warmed up properly and that power has been supplied to it. Start the standby pump following the normal procedures. Once its operation becomes stable, gradually reduce the opening of the valve on the main pump, open the minimum flow valve, until the outlet valve is fully closed. At that point, stop the pump, close the inlet valve, and open the drain valve to empty the liquid inside the pump. After it has cooled down, stop the cooling water supply, cut off the power, and hand over the pump for maintenance. IV. Emergency Plan (8 points) Provide an emergency procedure sheet for dealing with the shutdown of the two boiler feed pumps. 1 When neither pump can be started, contact the power and dispatch teams. Once the power and gasification systems are ready, prepare to divert boiler water from PIC180 at the Bw water inlet drain of 14-E3 to the gas holder and waste boiler in order to supply water to them properly. If the power and gasification systems are not ready, carry out an emergency shutdown: close HIC103, stop feeding material to the synthesis unit, and close FCV-203 as well as the subsequent valves. Fill the synthesis tower with N80 to cool it down, and allow venting at a controlled rate through PIC205, PIC214, and PIC105. V. Flow diagram. (18 points) Please draw the PID flow diagram for methanol synthesis.