Discussion on energy-saving and consumption-reducing ways of process compressor (1)

Discussion on energy-saving and consumption-reducing ways of process compressor (1)

Process compressors are important and key large-scale equipment for petrochemical companies. In the chemical industry, the energy consumption of process compressors is large, accounting for about 12%-32% of the company's total power consumption according to statistics. The economy and reliability of the operation of process compressors have always been at the forefront of professional research in domestic and foreign counterparts. However, for a long time, the energy saving and consumption reduction of process compressors have not attracted enough attention from domestic petrochemical enterprises. The technical personnel and management personnel of enterprises pay attention to reliability issues such as safe operation and do not pay attention to economic research. Therefore, improve process compression The production capacity of the machine, the reduction of operating costs, the increase of output and the reduction of the total energy consumption of the production equipment, are very necessary for the energy-saving potential of the process compressor.

　　The characteristics of operating conditions and analysis of ways to save power

Compared with other general purpose compressors, the operating conditions of process compressors have special requirements:

　　 (1) Continuity of operation. Process compressors are important moving equipment in chemical production, and generally strive for trouble-free long-term continuous and safe operation for more than 8,000 hours.

　　 (2) Corrosion and flammability of working fluid. The compressed medium is generally corrosive, and some process gases are also flammable and explosive. Therefore, the exhaust temperature is strictly limited.

　　 (3) Manufacturability. The operating parameters are restricted by the technological process, and the general operating conditions fluctuate below the rated conditions.

　　 (4) Complexity. In order to meet the process requirements, the compression medium has a variety of components, different compressor lubrication methods, inter-stage air extraction, air filling, and purification lamps may exist.

　　 Therefore, the energy saving of the process compressor must be combined with the actual operating conditions, and specific research and analysis must be carried out. Its economy and reliability are related to the cost and efficiency of chemical production.

　　 According to theoretical analysis, the power consumption of compressed gas is related to the compression process index. Reducing the compression process index can save compressor power. For this reason, the cylinder can be used to enhance heat exchange to try to improve heat exchange conditions and reduce the compression process index. Second, try to reduce power loss, which is also one of the main ways to save energy. Factors affecting power loss mainly include: (1) valve power loss during the intake and exhaust process; (2) friction loss of piston rings and packing; (3) other mechanical losses of moving parts; third, according to the long-term nature of chemical production It is especially important to improve the service life of wearing parts, extend the safe operation period, and reduce the loss caused by fault shutdown; fourthly, due to the long-term inconsistency of the compressor operating conditions and design conditions, it will also affect the compressor’s performance. operation efficiency. According to the actual operating conditions of the compressor, appropriate thermal parameters should be selected reasonably to improve operating efficiency.

　　The effect of cooling system on energy consumption

　　 Due to the characteristics of chemical production, process compressors are mostly large and medium-sized, high-pressure, multi-stage water-cooled compressors. The cooling system mostly adopts cylinder jacket water cooling and inter-stage cooler parallel or hybrid structure. The effect of the cooling system directly affects the power consumption and exhaust temperature. According to theoretical analysis, the cooling effect between stages decreases, which directly affects the power consumption of the next stage. Every time the temperature increases by 3 degrees, the power consumption of the next stage increases by about 1%. Cylinder cooling is mainly to reduce the compression process index, save power and reduce the terminal temperature of compressed gas, and make the cylinder effective and uniform temperature field. For this reason, adjust the appropriate cooling water flow rate and control the cooling water temperature during operation to make it have a better cooling effect and achieve the purpose of saving power.

　　 At a certain speed, there is an optimal cooling water flow problem. For process compressors, the volume flow and cylinder diameter are generally relatively large, and the gas heat derived from the cooling water through the cylinder wall is small. Especially at high speeds, the compression process index and adiabatic compression process index of the compressor have very little difference. However, the rotational speed of large-scale process piston compressors is generally low, mostly in the range of 150-400r/min. Therefore, process compressors should reduce the compression process index as much as possible according to the actual operating conditions and the optimal flow of cooling water. , In order to save power consumption, and make the cylinder have a more uniform temperature field, which is conducive to lubrication and improve the life of friction wearing parts.

　　For the process compressor, it should also be noted that the larger the cooling water flow, the better. Excessive cooling water will cause the temperature of the lubricating oil on the cylinder mirror to be too low, which will affect the performance of the lubricating oil, increase the friction power and increase the specific power.