A kind of dop continuous production process and used equipment

[0030] Example 1: Heating isooctyl alcohol to about 180°C, with 10 m 3 /h flow rate into the first esterification tank 101, after adding 5m3, start the agitator. Open the steam control valve, the first esterification kettle 101 isooctyl alcohol is slowly warmed up to 184 ℃, open the steam control valve of the second esterification kettle 102 to the sixth esterification kettle 106 simultaneously, control the temperature of these three reactors at Above 184°C, to avoid condensation of alcohol vapor in it, after adding octanol to the first esterification kettle 101 for 1 hour, determine the feeding ratio and input phthalic anhydride (4T/h) and catalyst 4.3Kg/h (catalyst pump stroke: 3.0) to start the catalyst Feed: control the temperature of the first esterification tank 101 to carry out the esterification reaction at 190°C, the alcohol and water vapor distilled from the top of the first esterification tower 107 are cooled by the first cooler 108, and the condensed alcohol-water mixture Enter the first separation tank 109, the alcohol overflows from the upper layer to the first esterification kettle 101, and the water flows out from the bottom drainage regulating valve; when the first esterification kettle 101 overflows to the second esterification kettle 102, sampling analysis, its Whether the excess alcohol is in the range of 20-24%, whether the acid value is in the range of 50mgKOH/g; the control of excess alcohol is adjusted by increasing or decreasing the amount of isooctyl alcohol to the first esterification tank 101, and the acid value is determined by the reaction temperature , excess alcohol and the amount of catalyst added to the first esterification tank 101; start the agitator half an hour after the first esterification tank 101 overflows to the second esterification tank 102, and adjust the first esterification tank according to the acid value The amount of alcohol added to the esterification tank 101 is the same as adding alcohol to the second esterification tank 102 at a flow rate of 0.5 m3/h, the temperature is controlled within the range of 200±2°C, and the second esterification tank 102 overflows to the third esterification tank 103 Finally, take a sample to analyze whether the acid value of the effluent material from the second esterification kettle 102 is qualified, and adjust the alcohol addition amount of the second esterification kettle 102, and start the agitator of the third esterification kettle 103 half an hour after the overflow, and simultaneously Recycle alcohol to the third esterification tank 103; control the temperature within the range of 2 to 10 ° C ± 2; after the third esterification tank 103 overflows to the fourth esterification tank 104, take samples and analyze the acid value of the third esterification tank 103 as soon as possible , whether the excess alcohol is qualified, and adjust it quickly, and half an hour after the overflow, start the agitator of the fourth esterification kettle 104, and add fresh alcohol to the fourth esterification kettle 104 at the same time, and appropriately reduce the amount of alcohol in the first esterification kettle 101. Fresh alcohol addition; control the temperature of the fourth esterification tank 104 at 215 ± 2°C; control the temperature at the top of the first esterification tower 110 to be 165°C-180°C; When 105 overflows, take a sample to analyze whether the acid value and excess alcohol of the fourth esterification kettle 104 are qualified, and adjust it to be qualified as soon as possible. After half an hour, open the fifth esterification kettle 105 to stir; the fifth esterification kettle 105 starts to the sixth esterification kettle 105. When the tank 106 overflows, take samples and analyze as soon as possible. The acid value of the fifth esterification tank 105 should be ≤1.2, and the excess alcohol should be 18-20%, otherwise, it should be adjusted in time by raising the temperature and adding alcohol; when the sixth esterification tank 106 starts to overflow When the acid value of the sixth esterification tank 106 is ≤0.3mgKOH/g, the excess alcohol is controlled at 17-19%, and the temperature is 235°C±2°C. After the esterification is completed, the crude ester is obtained in the crude ester tank 3 middle,.

[0031] Embodiment 2: Dealcoholization process: a. Utilize the residual heat of reaction materials, and separate most of excess alcohol through decompression flash evaporation; b. Reduce the emulsification factor of neutralization and washing, which is beneficial to the phase separation of neutralization and washing; c. Recover Part of octanol is used for esterification.

[0032] Put the crude ester of the esterification product obtained in Example 1 into the alcohol-ester heat exchanger 5 through the crude ester pump 4, and add another pipeline through low-temperature alcohol to perform heat exchange, initially cool the temperature of the crude ester, and then enter the The temperature in the ester cooler 6 is further lowered to about 95°C, and it is added to the dealcoholization tower. Under the condition of an absolute pressure of 5KPa, the temperature at the bottom of the tower is set at 190°C, and the temperature at the top of the tower is set at 170°C. Excess alcohol is evaporated by its own waste heat , the alcohol is distilled from the top of the tower, condensed and collected by the top condenser, and then returned to the esterification tank for recycling, and the temperature of the bottoms is lowered to 95-100°C for the next reaction, and the weight content of alcohol in the bottoms is <2 %, and then enter the neutralization tank 7 for neutralization.

[0033] Example 3: Neutralization and washing process: Tasks of this section: a. Use the waste heat of the reaction materials to separate most of the excess alcohol through decompression flash evaporation; b. Reduce the emulsification factor of neutralization and washing, which is beneficial to neutralization and washing phase separation; c. reclaim part of octanol for esterification.

[0034] In Example 2, the tower bottoms that have been dealcoholized and cooled to 95°C are sent to the neutralization tank 7, and the dilute solution diluted to 0.4% by 30% NaOH is added, and the temperature is raised to 90°C before being added to the neutralization tank , Stirring and neutralization reaction at a temperature of 95 ° C, until the acid value in the ester phase ≤ O. 05mgKOH/g, the pH value of the water phase is 11-12, after the reaction is completed, the ester phase enters the water washing kettle 8, and the water at 95°C whose mass is 20-30% of the ester content is added for washing, and after the water washing is completed, it enters the heat exchanger 9 and is heated to Above 100°C, then pass through the heater 10, heat to 145°C, and then proceed to the next step;