N-甲基二乙醇胺吸收法火炬气脱硫过程模拟

针对火炬气的工况,选择N-甲基二乙醇胺(MDEA)吸收法进行火炬气脱硫,以满足进一步利用火炬气的要求。采用AMSIM模块进行脱硫模拟计算,其中热力学方法选择Kent-Eisenberg模型。用炼油厂干气、液化气脱硫的实际操作数据对模拟方案进行检验,证明此热力学模型适用于MDEA吸收法脱硫过程的模拟。根据火炬气实际操作情况,分析了火炬气进口压力、碳氢化合物、吸收塔操作参数对脱硫性能的影响。模拟结果表明,当火炬气流量16000m3/h(标准状况下)、温度30℃、压力0.45MPa;循环MDEA溶液中MDEA质量分数25%、流量10.0m3/h、温度35℃;吸收塔的塔板数为15时,可将火炬气中H2S脱除到摩尔分数1.00×10-4以下,且具有较好的脱硫选择性。

Simulation of Desulfurization of Flare Gas by Absorption with N-Methyldiethanolamine

For the sake of removing hydrogen sulfide from flare gas,AMSIM module with Kent-Eisenberg thermodynamic model was used in simulation of absorption process with N-methyldiethanolamine(MDEA)as absorbent.The calculation was first checked by simulation of desulfurization of dry gas and liquefied gas from refinery.The model was proved to be appropriate for simulation of MDEA desulfurization.The effects of inlet pressure of flare gas,contents of hydrocarbons and operation parameters of absorber on desulfurization were then investigated.The main obtained parameters of absorber are as follows:flare gas temperature 30 ℃,pressure 0.45 MPa,flow rate 16 000 m~3/h;absorbent temperature 35 ℃,MDEA mass fraction 25%,flow rate 10.0 m~3/h;and absorber tray number 15.Under above conditions,mole fraction of H_2S in flare gas to be treated can be reduced to less than 1.00×10~ -4 with high desulfurization selectivity.