高含硫天然气脱酸气装置提效降耗优化

Efficiency improvement, consumption reduction and optimization of high-sulfur natural gas sweetening units

为了提高高含硫天然气脱酸气装置的净化气产量并降低净化过程的综合能耗,依据中国石化普光天然气净化厂脱酸气装置的现场运行数据,采用ProMax建立了相应的工艺仿真模型,针对主要操作参数包括甲基二乙醇胺(MDEA)溶液的循环量,浓度和进入一、二级吸收塔的温度等开展灵敏度分析与优化研究,并结合现场实际,在优化工况下,分析原料气负荷降低、压力降低及H——2S含量升高对净化气气质与收率的影响规律。研究结果表明:①降低MDEA溶液循环量、浓度以及进塔温度可提高胺液吸收的选择性,有利于提高净化气的收率,其中MDEA溶液循环量是影响脱酸气装置综合能耗的主要因素;②当原料气负荷、压力以及H2S含量波动时,在优化工况下能够满足高含硫天然气的净化要求;③在低负荷下可通过减少再生蒸汽量和调整胺液进二级吸收塔位置实现节能;④H2S含量每增加1%,需将MDEA溶液循环量提高约20×10~3 kg/h;⑤经过参数优化,在满负荷工况下净化气收率可以提高0.5%,综合能耗降低19.1%。

To increase purified gas production and reduce the comprehensive energy consumption of high-sulfur natural gas sweetening units,we established a process simulation model using the ProMax,based on the field operation data of a gas sweetening unit in the Sinopec Puguang Natural Gas Purification Plant.Then,sensitivity analysis and optimization study were carried out on the main operating parameters,including circulation rates,the concentrations and the inlet temperatures of primary and secondary absorption towers of MDEA(methyldiethanolamine)solutions.Finally,the effects of feed gas load reduction and pressure reduction and H2S content increase on the quality and yield rates of purified gas were analyzed under the optimized operating conditions,combined with the actual field situations.And the following research results were obtained.First,the absorption selectivity of MDEA solutions can be improved by decreasing the circulation rates,concentrations and inlet temperatures of MDEA solutions,which is favorable for the increase of the yield rates of purified gas.Specifically,the circulation rate of MDEA solution is the main factor influencing the comprehensive energy consumption of a high-sulfur natural gas sweetening unit.Second,when the flow rate,pressure and H2S content of feed gas fluctuate,the purification requirements can be satisfied under the optimized operating conditions.Third,energy conservation under low flow rates of feed gas can be achieved by reducing the flow rates of regenerated steam and adjusting the position of MDEA solutions entering the secondary absorption tower.Fourth,as H2S content is increased by 1%,it is necessary to increase the circulation rate of MDEA solution by about 20×10^3 kg/h.Fifth,after parameter optimization,the yield rate of purified gas is increased by 0.5%and the comprehensive energy consumption is reduced by 19.1%under the operating condition of full load.