A method for recovering ammonia and water and preparing ammonia water in the production process of polyetheramine

Abstract

The invention discloses a method for recovery of ammonia and water and preparation of ammonia water in production of polyetheramines, and relates to a recovery technology of ammonia and water in fined chemical industry. The ammonia and ammonia containing wastewater discharged in the production of polyetheramines are mixed and then introduced into an ammonia distillation tower and rectified to obtain gas-phase ammonia, the gas-phase ammonia is cooled, 95 to 97% of the cooled gas-phase ammonia is compressed to form liquid ammonia to be reused for a fixed bed reactor, 3 to 5% of the cooled gas-phase ammonia enters a stronger ammonia water absorption tower to be subjected to circulating cooling with ammonia containing wastewater at the bottom of the ammonia distillation tower to obtain stronger ammonia water. The method disclosed by the invention solves the problem of excessive ammonia and water in the production of polyetheramines, and avoids the phenomena of environmental pollution and resource waste generated by directly discharging ammonia and water to reach the purposes of protecting environment, recycling NH3 (Ammonia) resources and the like.

Description

technical field [0001] The invention relates to the recovery technology of ammonia and water in the fine chemical industry, in particular to the technical field of recovering ammonia and water and preparing ammonia water in the production process of polyetheramine. Background technique [0002] Polyetheramine is a kind of compound whose active functional group is amine group and the main chain is polyether. In the industrial production of polyether amine, batch method or continuous method is generally adopted, and the preparation process of catalytic amination reaction of polyether polyol, long-chain aliphatic alcohol or aromatic alcohol compound with ammonia, regardless of batch method production Or the continuous production process is carried out under the situation of a large excess of ammonia. Since the production of polyetheramine by the catalytic amination method will have a by-product water process, it is necessary to refine the polyetheramine after the ammoniation r...

AI Technical Summary

Problems solved by technology

The recycling and utilization of existing ammonia mainly adopts the following methods: (1) Use the principle of rectification to directly produce liquid ammonia through processes such as ammonia distillation; however, there will be a lot of steam consumption and electricity consumption in the ammonia distillation process, Does not comply with the national industrial policy

(2) Use phosphoric acid, sulfuric acid and other acids as absorbents to neutralize ammonia in waste ammonia water, and then add precipitant or crystallization method to recover ammonia; this process will generate a large amount of hazardous waste, which neither meets the requirements of environmental protection, nor Increase the production cost of the enterprise

(3) The catalytic combustion method is used to decompose ammonia into nitrogen and water vapor. The investment cost of this process is too high and the process is difficult to control

(4) Prepare ammonia water with water as an absorbent; although ammonia gas is very soluble in water, ammonia water with a high concentration has certain commercial value, but it is difficult to achieve ≥ 25% of the commercial product requirements by using conventional water absorption methods On the other hand, the absorption rate of ammonia is low, only about 90%, and there will still be a large amount of ammonia discharged into the environment

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