位阻胺选择性配方溶剂尾气处理装置工业应用

为了解决常规甲基二乙醇胺(MDEA)脱硫溶剂在低压下脱硫效果不理想,导致排放尾气中SO_2浓度升高的问题,利用位阻胺与H_2S反应具有良好活性、同时能较好抑制位阻胺与CO_2反应的特点,研究开发出了位阻胺选择性脱硫配方溶剂,并在处理量为1×10~4m~3/d的装置上进行中间放大试验的基础上,在中国石油西南油气田公司川中油气矿龙岗天然气净化厂硫磺回收加氢尾气脱硫装置上进行了工业应用。在工业应用期间,考察了溶剂在不同吸收塔板数、不同贫液入塔温度、不同溶液循环量等条件下的吸收性能,还考察了脱硫溶液的再生性能,确定了较适宜的工艺操作参数。应用1年后的考核结果表明:(1)该位阻胺选择性脱硫配方溶剂在进尾气脱硫吸收塔气体中H_2S含量为0.77%～3.96%、CO_2含量为23.91%～32.79%的气质条件下,可使净化尾气中H_2S含量低于30 mg/m~3;(2)与装置原用的常规MDEA相比,净化尾气中H_2S含量降低58.45%;(3)该位阻胺选择性脱硫配方溶剂的再生性能良好,再生后贫液中H_2S和CO_2含量均小于0.12 g/L。

A selective formulated solvent based on steric hindered amine applied to tail gas treatment

Due to the MDEA's unsatisfactory desulfurization performance at low pressures, which leads to the increase of SO2 concentration in tail gas release, a formulated solvent based on steric hindered amine (SHA) was thus developed, in virtue of SHA's good absorbing activity with H2S and lower reacting inclination with CO2. This solvent was applied first to a pilot plant with the capacity of 10 thousand m3/d and then formally to the Claus hydrogenation tail gas desulfurization units in the Longgang Natural Gas Purification Plant operated by the PetroChina Southwest Company. During this solvent's industrial application time, its absorbing performance was evaluated under different conditions such as numbers of contact plates of the absorbing tower, lean amine temperatures into the absorbing tower, amine cycling amounts, etc., based on which the operating parameters were optimized. In addition, the recycling of desulfurizing solutions was examined and the favorable operating parameters were determined. After one year's application, the following findings were achieved. With this solvent in treatment, the H2S content in the desulfurized tail gas (originally, there was 0.77–3.96% H2S and 23.91–32.79% CO2), was reduced to less than 30 mg/m3, and by 58.45% compared to the MDEA previously used in this desulfurization plant. The rich amine solution can be easily regenerated with both H2S and CO2 content less than 0.12 g/L in the regenerated lean amine stream.