Application And Study Of Energy Recovery Technology Of Low Temperature Methanol Washing Process

At present, the problem of energy shortage and low energy utilization is becoming more and more serious, and the energy waste of high pressure liquid in low temperature methanol washing process has attracted the attention of researchers. In view of the present situation, energy recovery device with the core of a turbine pump unit was added to the low temperature methanol washing process and the research on the recovery system of the device was carried out. The energy recovery device works by the high pressure liquid in the process, which will drive the turbine pump rotor, then the device achieves energy recovery and utilization. The application of the residual pressure energy recovery device can not only realize the recycling of energy, but also can bring good economic benefits for the enterprise.Firstly, the overall structure of the residual pressure energy recovery system was analyzed, and the process control scheme based on the turbine pump unit was presented. Three PID control valves with different sizes are used, and in different circumstances, the purpose of stabilizing the level of the absorption tower could be achieved by controlling the opening of the three control valves. The recovery efficiency and performance of the turbine pump and the working principle was analyzed. Then the starting characteristic of the turbine pump was studied, and the turbine pump was controlled by 505 speed regulator, so that the turbine pump could rise smoothly in accordance with the designed curve, and this had avoided the critical speed and the damage to the turbine pump. A reasonable lubricating oil system was designed for the energy recovery device, and the turbine pump can be started at a certain oil pressure, and it could run at a reasonable lubrication interval to ensure the stability of the liquid level in the methanol washing tower.The control logic and the safety interlocking logic of the energy recovery device was designed in detail, and it could ensure the safe operation of the turbine pump, and at the same time it would not cause the burden on the original process.According to the process flow of the system, the electrical control and human-computer interaction interface had been designed. Through the analysis of the process diagram, the S7-300 controller was adopted as the core of the system. The S7-200 controller was used to realize the Modbus communication with the DCS system. Programming software and the related various modules and the communicating settings was described in detail,so it could achieve the intelligent control and the stable control of the system. The monitoring interface,the parameter interface, the interface of PID and the interface of the alarm of the energy recovery system had been designed by using the TIA, so the user can see the operation of the system conveniently and directly. The introduction of the monitoring interface can not only ensure the safe operation of the system, but also realize the intelligence of the whole system.