The processing rate is increased by more than 50%! CNOOC Zhongli Company’s VOCs environmental protection management adds new impetus

In order to further solve the problem of VOCs environmental protection, Zhongli Company has carried out a series of technical transformation work on the oil and gas recovery device in the second production area. The crude oil gas recovery device uses normal temperature or high temperature diesel as the VOCs gas adsorbent. The adsorption efficiency is low. The oil and gas recovery activated carbon tank is quickly saturated in a short time. The activated carbon needs to be replaced every two to three months. At the same time, a large amount of hazardous waste is generated, and additional equipment processing is required. Afterwards, the gas concentration remained high and it was completely impossible to achieve emission standards. In order to break this deadlock, a new set of screw refrigeration compressor skid-mounted equipment was added to the oil and gas recovery unit. The low-temperature diesel adsorbent effectively improved the oil and gas processing capacity of the oil and gas recovery equipment.

　1 Energy saving and consumption reduction

　The equipment uses R134a refrigerant and multi-stage heat exchange method, which effectively improves the cooling efficiency of the equipment. efficiency and reduce energy consumption. The diesel adsorbent in the oil and gas recovery unit is first pre-cooled through a plate heat exchanger. After the adsorbent temperature drops from 40-45°C to about 25°C, it enters the screw refrigeration compressor unit and finally drops to 10-15°C to reach the target temperature. In addition, the main body of the equipment and supporting pipelines have been cold-insulated. The power of the supporting equipment is 90 kilowatts. The current operating power is calculated to be 25-27 kilowatts, which is in a low power consumption state.

　2 Automation technology

The equipment realizes automated and precise control, reduces manpower investment, and improves the stability and reliability of VOCs processing. safety, high equipment safety, and simple daily operation and maintenance. Through the use of high-precision regulating valves, the equipment's operating temperature, pressure, liquid level and other indicators are precisely controlled. After the equipment's process parameters are set, it can achieve fully automatic operation; the equipment itself is equipped with multiple chain protection settings. During the debugging period, it underwent multiple destructive tests. Verification, process chain can be quickly achieved; the equipment is connected to the DCS system of the operation room through RS485 communication, and the employees on duty in the operation room can The operating status and parameters of the equipment can be checked at any time on the "_blank">operating system. Problems can be discovered and dealt with in time. Daily maintenance is simple and does not require too much manpower and material resources.

3 Application Effect

The equipment was put into trial operation on August 15, 2023. After actual testing,the volatile organic compound VOCs gas treatment rate increased by more than 50%, the average oil and gas concentration dropped from the original 25000-30000ppm to 1500-2500ppm; the oil and gas recovery device passes through the cold diesel adsorbent, increasing the daily average oil recovery volume by 165-180 kilograms compared with the previous year, and the average annual oil recovery volume The production volume is increased by 60-66 tons, and the recovered oil can be directly used as raw material for the precision fractionation unit; after the equipment is put into use, the activated carbon only needs to be replaced once a year, which directly saves the cost of replacing activated carbon 3-4 times a year.

The commissioning of the refrigeration unit of the oil and gas recovery device is a major breakthrough for Zhongli Company in VOCs control. The application effect of the refrigeration unit during the trial operation far exceeded expectations, and it is an important factor in solving environmental protection problems. At the same time, it creates economic benefits, provides new ideas and new methods for future VOCs management, and adds new impetus to Zhongli Company’s green development.

Source | Offshore Oil Green Low Carbon

Original title: Zhongli Company’s VOCs environmental protection management adds new impetus