Diesel hydrogenation test questions

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1. What is the impact of crude oil properties on temperature rise? 1. The temperature rise of crude oil containing sulfur, nitrogen, and dry points is high ； Rigorous refining conditions are required. 2. The temperature rise of straight-run gasoline and inert oils in the feed oil is low. 3. The temperature rise of the gasoline produced by coking of the feed oil is high. 4. The bromine value shows a large increase at high temperatures, but purification is easy; olefin saturation occurs in the catalyst bed. 5. If the feed oil contains water, the temperature rise is reduced. 2. What are the measures to increase the reaction depth? 1. Increase the reactor inlet temperature. 2. Improve the purity of the recycled hydrogen. 3. Increase the reaction pressure. 4. Replace with a highly active catalyst. 5. Reduce the space velocity. 6. Increase the hydrogen-to-oil ratio. 3. How to control the reaction temperature? The reactor inlet temperature is controlled by adjusting the outlet temperature of the heating furnace, while the temperature rise in the catalyst bed is kept within a reasonable range by adjusting the amount of cold hydrogen injected into the bed. During operation, it is necessary to strictly adhere to the principles of \"increasing the volume first before raising the temperature, and reducing the volume first before lowering the temperature.\" Hydrogenation refining is a highly exothermic reaction. Generally, the heat generated by the hydrogenation reaction and the heat removed from the catalyst bed by the reaction stream are in balance; under normal conditions, the temperature of the hydrogenation catalyst bed remains stable. If, for some reason, the amount of heat removed from the bed by the reaction stream is less than the heat generated by the reaction, this imbalance can lead to a chain reaction of rising temperatures, intense heat release, and further temperature increases. Such a situation poses a serious threat to personnel, equipment, and the catalysts. To address this issue, hydrogenation units are equipped with an emergency pressure relief system with a capacity of 0.7 MPa/min. When necessary, this system must be activated to quickly release pressure, thereby removing a large amount of heat and preventing the reaction temperature from rising further. 4. How can the hydrogen partial pressure be increased? 1. Increase system pressure. 2. Increase the flow rate of recycled hydrogen. 3. Improve the purity of the hydrogen used as a supplement. 4. Increase the amount of waste hydrogen discharged. 5. Improve the purity of recycled hydrogen. 6. Reduce the amount of low-pressure gas fed into the inlet of the new hydrogen generator. 5. What impact does the hydrogen-to-oil ratio have on the oil used in the hydrogenation reaction? Answer: During hydrorefining, maintaining a high hydrogen partial pressure helps to suppress the condensation and coking reactions. To this end, the hydrogen-to-oil ratio used in the hydrogenation process far exceeds the value required for the chemical reaction. A large amount of circulating hydrogen and cold hydrogen can increase the heat capacity of the reaction system, thereby reducing the magnitude of changes in reaction temperature. It also allows a large amount of heat of reaction to be removed from the reactor, slowing down the temperature rise in the catalyst bed and thus expanding the temperature range within which the catalyst can be used. Although increasing the hydrogen-to-oil ratio has advantages in various aspects, it increases power consumption and operating costs. 6. What are the reasons for the high sulfur content in refined diesel, and what are the solutions? Answer ； 1) The feed of raw materials is uneven, and the sulfur content in the raw materials themselves is high. 2) The reaction temperature is too low. 3) The gas-to-oil ratio is too low. 4) High air velocity. 5) Fluctuations in the distillation section led to incomplete removal of hydrogen sulfide. 6) An internal leak occurred in the high-pressure heat exchanger, causing the raw material to mix with the reaction products. 7) Carbon deposition on the catalyst has caused a significant decline in its activity. process ； 1) Adjust the feed ratio to reduce the sulfur content in the crude oil. 2) Slightly increase the reaction temperature. 3) Increase the load on the recycle hydrogen compressor to raise the gas-oil ratio. 4) Slightly reduce the space velocity. 5) Make careful adjustments and operate strictly in accordance with the process specifications. 6) Remove the heat exchanger and use a bypass line. Shut down for treatment when the leakage volume is large. 7) If it is determined that the catalyst activity has decreased significantly, the catalyst needs to be regenerated or replaced with a new one. 7. What are boiling point, dew point, and bubble point? Answer ； boiling point ； Under specified conditions, the temperature at which heating an oil causes it to boil; dew point ； The temperature at which the first small droplets appear in the cooling oil under specified conditions. bubbling point ； The temperature at which the first small bubbles appear in the heated oil under specified conditions. 8. How to control the flash point of diesel? Answer ； 1) Control the bottom temperature of the tower well. 2) Control the circulation rate and return temperature of the reboiler. 3) Maintain a stable feed rate and feed temperature. 4) Control the top temperature of the tower and the reflux volume. 5) Adjust operations promptly when there are changes in the composition. 6) Control the top pressure of the tower. 7) Prevent water from being carried in with the feed and reflux