Abstract

This article details the entire process of installation and commissioning of the latest DMF (N, N-dimethylformamide) recovery equipment developed by Environmental Protection Technology Company in the customer’s factory. The article first introduces the background significance and industry status quo of DMF recovery, and then comprehensively elaborates on the technical principles and innovative features of the equipment. It focuses on describing the specific steps and precautions for the installation and commissioning of the equipment, and demonstrates the outstanding performance of the equipment through actual operation data. Finally, the article looks forward to the application prospects of this equipment in industries such as chemical engineering and pharmaceuticals, as well as its positive contribution to environmental protection. This article provides valuable experience references for equipment installation and commissioning for technicians in related industries.

Key words:

DMF RECOVERY PLANT, DMAC RECOVERY PLANT, DMSO RECOVERY PLANT, ENVIROMENTAL PROTECTION EQUIPMENT

Introduction

With increasingly strict global environmental protection regulations and the deep-rooted concept of sustainable development, the chemical industry is facing unprecedented environmental protection pressure. DMF, as an important organic solvent, is widely used in industries such as polyurethane, pharmaceuticals, and electronics. However, its high toxicity and difficulty in degradation also pose a serious threat to the environment. The traditional DMF treatment methods are mostly incineration or simple treatment, which not only cause waste of resources but also generate secondary pollution. In response to this industry pain point, XX Environmental Protection Technology Company spent three years on research and development and successfully launched a new generation of highly efficient DMF recovery equipment. This equipment adopts advanced molecular sieve adsorption-distillation coupling technology, which can achieve a DMF recovery rate of ≥98% and a purity of ≥99.9%, far exceeding the industry average.

The client for this installation and commissioning is a well-known domestic polyurethane production enterprise, with an annual DMF usage exceeding 5,000 tons. After the equipment installation is completed, it is expected to recover over 4,800 tons of DMF for customers annually, generating direct economic benefits of more than 20 million yuan. At the same time, it will reduce CO2 emissions by approximately 12,000 tons, demonstrating significant environmental benefits. This article will systematically introduce the installation and commissioning process of this equipment to provide a reference for similar projects.

Technical Principles and Composition of the Equipment

The DMF recovery equipment of customer Company is based on the three-stage process route of “pretreatment – molecular sieve adsorption – vacuum distillation”, achieving efficient recovery and purification of DMF. The core components of the equipment include: waste gas pretreatment system, molecular sieve adsorption tower group, vacuum distillation column, condensation system, automatic control system, etc. The pretreatment system adopts multi-stage filtration and dehumidification technology to ensure that the waste gas entering the adsorption section meets the requirements. The molecular sieve adsorption tower adopts a double-tower alternating operation design to achieve continuous operation. The distillation section adopts high-efficiency structured packing and falling film reboiler, significantly reducing energy consumption.

Compared with similar products on the market, this equipment has three major innovation points: First, it has developed a modified molecular sieve material that can withstand high temperature and high humidity, extending its service life by 50%. The second is to adopt heat pump distillation technology, reducing energy consumption by 30%. The third is to integrate an intelligent control system to achieve fully automated operation and remote monitoring. The processing capacity of the equipment covers multiple specifications ranging from 1000 to 10000 nm ³/h and can be customized according to customer requirements.

Equipment Installation Process

Before the equipment installation, customer Company dispatched a professional technical team to conduct a detailed on-site investigation of the customer and formulated a meticulous installation plan. The installation process is mainly divided into the following stages:

Foundation construction and acceptance: Pour the concrete foundation in accordance with the equipment load requirements, reserve the anchor bolt holes, and conduct a levelness test after the curing period to ensure that the deviation is ≤2mm/m.

Equipment positioning and assembly: Use a 100-ton truck crane to hoist the main equipment into position, and install the main components such as the pretreatment module, adsorption tower group, and distillation tower in sequence. The key steps include: adjustment of the verticality of the adsorption tower (deviation ≤1/1000H), sealing treatment of pipe flanges (using PTFE gaskets), construction of insulation layers, etc.

Electrical instrument installation: Lay power cables and signal lines, install temperature, pressure and flow sensors, and complete the wiring of the control cabinet. Special attention should be paid to ensuring that the explosion-proof area complies with the requirements of the ATEX standard.

Public utility connection: Connect to the cooling water system (pressure 0.3-0.5MPa), steam system (pressure 0.6MPa), compressed air system (pressure 0.7MPa, dew point -40℃) and power system (380V, 50Hz).

The biggest challenge encountered during the installation process was the connection between the distillation column and the existing factory pipeline. Due to space limitations, the project team designed special transition connectors and adopted laser ranging to ensure the connection accuracy. The entire installation process lasted for 18 days and was completed two days ahead of schedule.

Equipment Debugging and Optimization

Equipment commissioning is divided into three stages: single-machine commissioning, interlocking commissioning and process commissioning.

During the single-machine commissioning stage, the operating conditions of dynamic equipment such as fans (vibration value ≤2.8mm/s), pumps (bearing temperature ≤75℃), and valves (leakage rate ≤0.1%) were tested in sequence, and all instrument signals were calibrated (error ≤1%FS). Three wiring errors were found and corrected in time.

During the linkage debugging stage, the overall performance of the system is tested under simulated actual operating conditions. The key indicators such as the adsorption tower switching program (switching time ≤30 seconds), the sealing performance of the vacuum system (system leakage rate ≤0.5mbar·L/s), and the safety interlock function (response time ≤1 second) were verified emphatically. The PLC control parameters were optimized through debugging, making the system run more smoothly.

During the process commissioning stage, the actual production waste gas is gradually introduced and the process parameters are adjusted to the design values. The recorded data show that under the condition of an imported DMF concentration of 8-12g/Nm³, the adsorption efficiency reaches 99.2%, the purity of DMF after distillation is 99.95%, and the water content is ≤0.05%, meeting the performance guarantee values stipulated in the contract. During the commissioning, it was also found that the pressure drop in the pretreatment section was relatively high. By adding a pre-filter and optimizing the gas flow distribution, the system resistance was reduced by 15%.

Operation Effect and Customer Feedback

After continuous operation for one month, all indicators remained stable and excellent: the average DMF recovery rate was 98.7%, the product purity was 99.92%, and the unit energy consumption was 35% lower than that of traditional equipment. The customer did an economic calculation: The equipment investment was approximately 8 million yuan, the annual operating cost was 1.5 million yuan, and the value of the recovered DMF reached 21 million yuan. The investment payback period was only 8 months, and the economic benefits far exceeded expectations.

The environmental benefits are equally significant: After third-party testing, the residual concentration of DMF in the exhaust gas is less than 5mg/Nm³, which is far lower than the national emission standard (40mg/Nm³). If the DMF content in the wastewater is less than 10mg/L, it can be directly introduced into the sewage treatment system of the factory area. The head of the customer’s EHS department stated: “This set of equipment not only resolves our environmental compliance issues but also creates considerable economic value. It is truly green technology.

Conclusion

The successful installation and commissioning of the DMF recovery equipment this time marks another solid step forward for Customer Company in the field of organic solvent recovery. The outstanding operational performance of the equipment has verified the correctness of the technological innovation route and provided replicable solutions for the industry. Looking ahead, with the advancement of the “dual carbon” goals, high-efficiency solvent recovery equipment will enjoy a broader market space. Customer Company will continue to invest in research and development, launch more energy-saving and environmentally friendly products, and contribute to the green transformation of the chemical industry.