油田伴生气凝液回收工艺改进研究

Study on condensate recovery scheme improvement of oilfield associated gas

关键词:  油田伴生气  工艺改进  冷量利用  换热网络  丙烷回收 

Key words:  oilfield associated gas  scheme improvement  cold energy utilization  heat exchanger network  propane recovery

摘要:

油田伴生气气质富、压力低,普遍采用直接换热工艺回收丙烷及丙烷以上重烃,存在系统冷量利用不合理、气质适应性差、系统能耗高等问题。以某油田油气处理厂装置为例,以提高装置整体经济效益为目标,提出了工艺改进方案。改进工艺采用两级分离方式,脱乙烷塔塔顶增设回流罐,降低重接触塔塔顶进料中丙烷含量,增强重接触塔的吸收作用,提高丙烷收率；应用夹点理论设计冷箱的换热网络,提高系统的冷热集成度和冷量利用率,冷箱改进后,脱乙烷塔塔底重沸器负荷降低189 kW,降幅12.9%,丙烷制冷压缩机负荷减小142.8 kW,冷量利用更加合理。工艺改进后装置丙烷收率和液化石油气产量得到了大幅提高,装置总体能耗变化不大,改进工艺每年可提高装置经济收益1 797万元,经济效益可观,建议在类似工况条件下推广应用。 

Abstract:

To treat oilfield associated gas with rich quantities and low pressure, direct heat exchange technology is used to recover propane and products. Problems of unreasonable utilization of system cold energy, poor adaptability of gas composition and high system energy consumption are generally existed. Taking an oil and gas processing unit as example, the improvement scheme is put forward to improve the overall economic benefits of the unit. Two-stage separation process is used. The propane recovery rate is increasing by adding reflux tank on the top of deethanizer, reducing the propane content in top feed of DHX tower, enhancing absorption effect of DHX tower; and the heat exchanger network of cold box is designed with the pinch point theory to improve the cold and heat integration of system and the utilization rate of cooling energy. After improving of cold box, the reboiler load of deethanizer reduces 189 kW, decreasing of 12.9%,the compressor load of propane refrigeration reduces 142.8 kW, and the utilization of cold energy is more reasonable. By improving scheme, the rate of propane recovery and the production of liquefied petroleum gas have increased greatly, the overall energy consumption of unit have changed little, and a considerable economic benefit would be achieved. Suggestions are recommended for application in similar working condition.