Description

Project Overivew 

This Ammonium Chloride Evaporation & Crystallization Project intergrated with a DMF Distiilation System is designed to efficiently recover high-purity ammonium chloride crystals and dimethylformamide (DMF) solvent from process solutions containing ammonium chloride, DMF, and water. By combining advanced evaporation, crystallization, solid-liquid separation, and distillation technologies, the system enables effective recovery and reuse of valuable materials while reducing operating costs, and environmental impact.

The solution is particularly suitable for treating chemical and advanced material manufacturing processes where ammonium chloride and DMF are present in process streams. Recovered ammonium chloride can be collected as a valuable solid product, while purified DMF can be returned to the production porcess for reuse, supporting resource efficiency, waste minimization, and circular manufacturing. 

Process Technology     

Based on the characteristics of the feed solution and the required product quality, the project adopts a single-effect forced circulation evaporative crystallization system for ammonium chloride recovery, integrated with a multi-stage distillation system for DMF purification.

Ammonium Chloride Evaporation & Crystallization

The ammonium chloride solution is continuously circulated through the forced circulation evaporator, where water is evaporated and the solution is progressively concentrated.

As the ammonium chloride concentration increases and the solution reaches a supersaturated state, crystallization takes place. The resulting crystal slurry is transferred to the crystallization section to promote further crystal growth before being discharged to a centrifuge for solid-liquid separation.

The recovered ammonium chloride crystals are collected as the final solid product. The separated mother liquor is returned to the evaporation system for further concentration and crystallization, forming a continuous recycling loop that maximizes ammonium chloride recovery.

The forced circulation configuration provides a high circulation velocity through the heat exchanger, helping to control scaling and reduce the risk of blockage under high-salt-concentration operating conditions.

DMF Recovery & Purification

During the evaporation process, the generated secondary vapor contains water vapor together with DMF. This vapor is directed to the DMF distillation section for separation and purification.

Through staged distillation, water and other volatile components are progressively separated from DMF. The recovered DMF can be purified to up to 99 wt.%, depending on the feed composition and operating conditions, enabling its potential reuse in the customer’s production process.

This integrated configuration allows the system to recover both valuable inorganic salts and organic solvents from the same process stream, improving overall material utilization and reducing waste generation.

Equipment Description

The system consists primarily of a single-effect forced circulation evaporative crystallization system integrated with the first-stage DMF distillation tower and associated separation and anxuliary equipment. 

The main process equipment includes:  

•  Forced circulation evaporator

•  Crystallizer

•  Centrifuge for solid-liquid separation

•  DMF distillation column(s)

•  Condensers and associated heat exchangers

•  Pumps and process circulation equipment

•  Product collection and discharge system

•  PLC-based automatic control system

The system is engineered as an integrated process package to ensure stable operation, efficient material recovery, and convenient process control.

System Features

Our integrated recovery system offers the following advantages:

• High recovery efficiency

Maximizes the recovery of both ammonium chloride crystals and DMF solvent, improving product yield and economic value.

• Forced circulation evaporative crystallization

High circulation velocity effectively prevents heat exchanger tube blockage caused by high salt concentrations, minimizes scaling, enhances heat transfer efficiency, extends continuous operating time, and reduces cleaning frequency.

• Energy-efficient design

The evaporation and distillation processes are designed with optimized heat utilization and process integration to  reduces fresh steam consumption and lowers overall operating costs.

•  Reliable and continuous operation

The system is designed for continuous operation with robust process equipment, optimized circulation, and reliable solid-liquid separation, providing stable performance under demanding high-concentration operating conditions.

•  Advanced automation

A PLC-based control system enables automatic monitoring and control of key operating parameters, including temperature, pressure, liquid level, flow rate, and process concentration. This reduces manual intervention and improves operational stability and safety.

•  Robust equipment design

Equipment and process configurations are selected according to the characteristics of ammonium chloride and DMF-containing solutions. The system incorporates appropriate safety and operational measures to ensure reliable performance throughout the process.

•  Flexible system configuration

The system can be customized according to different feed compositions, processing capacities, product specifications, recovery targets, and site conditions, providing a flexible solution for different chemical and material-processing applications.

Sustainable Resource Recovery

By integrating salt crystallization and solvent recovery into a single process system, the project provides an effective approach to converting process waste streams into reusable resources.

The recovered ammonium chloride crystals and purified DMF can potentially be returned to the production chain, reducing raw-material consumption and waste generation while improving the overall economics of the process.

This project demonstrates our capability to provide integrated evaporation, crystallization, and solvent recovery solutions for complex chemical process streams, helping customers achieve greater resource efficiency and more sustainable production.

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