The acrylonitrile, concentrated sulfuric acid and isobutylene are used as raw materials, and the crude product of 2-acrylamido-2-methylpropanesulfonic acid is obtained by one-step synthesis method, and then refined to obtain the final product.
The main production processes of this project are divided into three parts: synthesis process, refining process and solvent recovery.
The synthesis process of this project adopts one-step synthesis method to prepare 2-acrylamido-2-methylpropanesulfonic acid: firstly, concentrated sulfuric acid is dissolved in excess acrylonitrile at low temperature to form an unstable amide sulfonate, followed by The isobutene is vaporized, and then the reaction mixture is heated to room temperature to continue the reaction. After the reaction is cooled, the mixture is centrifuged, and the crude material is introduced into a reaction vacuum dryer. After drying, a white crystalline crude product is obtained. The gas phase of the dryer is condensed by the condenser, enters the acrylonitrile drying temporary storage tank, and finally put into the acrylonitrile rectification system for recovery. The dryer does not condense (acrylonitrile, isobutylene) into the acrylonitrile waste gas treatment system, and is condensed by the deep condenser. After the activated carbon is absorbed, it is evacuated through a 25 m high exhaust cylinder. The dried crude part is sold out and partially enters the refining process.
(2) Refining and drying process
The prepared acetic acid is transferred from the acetic acid preparation pump to the dissolution tank according to the required amount, and the crude product in the reaction dryer is mixed with acetic acid in a dissolution kettle, stirred uniformly, and then transferred to a purification kettle to be heated and dissolved, and the temperature is lowered to a predetermined temperature. The solvent is distilled off under reduced pressure, and the distilled gas is recovered by secondary condensation. After the vacuum pump, the gas is not condensed (acetic acid) into the acetic acid waste gas treatment system, and after being absorbed by the water spray, it is evacuated through a 25 m high exhaust cylinder. The material in the refined kettle is refined and cooled, and then centrifuged by a refining centrifuge. The mother liquor is refined into a mother liquor tank, and the wet material is dried in a vacuum dryer and dried to obtain a fine product. The gas phase of the dryer is condensed by the condenser, enters the acetic acid drying temporary storage tank, and finally put into the acetic acid recovery tank. After the vacuum pump, it does not condense into the acetic acid waste gas treatment system, and after being absorbed by the water jet vacuum pump, it is also evacuated through the 25m high exhaust cylinder.
(3) Solvent recovery process
(a) Acrylonitrile rectification
The material is transferred from the synthetic mother liquid tank and the acrylonitrile drying temporary storage tank to the acrylonitrile recovery tank, heated and distilled, and the distilled acrylonitrile and isobutylene enter the acrylonitrile rectification column, and the top gas is condensed by the second stage and sent to the reflux tank. In the middle, the reflux pump is fully recirculated, and after the vacuum pump, the non-condensable gas (acrylonitrile, isobutylene) is discharged through the 25m high exhaust cylinder through the acrylonitrile tail gas treatment system. The residual liquid in the recovery tank is entrusted to be processed by a qualified unit.
(b) Acetic acid distillation
The material is inhaled by acetic acid recovery from the refined mother liquor tank and the acetic acid drying temporary storage tank, and heated to perform vacuum distillation. The distilled acetic acid is condensed by the second stage and then enters the acetic acid mother liquor tank, and the non-condensable gas (acetic acid) is treated with the acetic acid tail gas treatment system through the water. After the spray is absorbed, it is discharged through a 25m high exhaust cylinder, and the residual liquid in the recovery tank is entrusted to be processed by a qualified unit. The acetic acid in the acetic acid mother tank is pumped into the acetic acid rectification column and subjected to vacuum distillation. The gas at the top of the tower is cooled by the secondary condenser and sent to the reflux tank. The bottom of the gas is discharged into the acetic acid recovery tank. The acetic acid extracted from the side line is condensed and cooled, and then pumped into the finished acetic acid tank, which is used as a raw material for backup. After the vacuum pump, it does not condense (acetic acid). ) Entering the acetic acid tail gas treatment system, after being absorbed by water spray, it is discharged through a 25m high exhaust cylinder.
The activated carbon produced in the acrylonitrile tail gas treatment system is used as a hazardous waste, and is commissioned by a qualified unit. The vacuum pump and the spray tower in the acetic acid tail gas treatment system contain acetic acid, and after returning to the rectification column for rectification, the acetic acid solution is sent to the refining section.