分子筛脱水装置再生气中H2S含量升高原因解析及整改措施

Analysis of Causes and Rectification Measures of Hydrogen Sulfide Content Increasing in Regeneration Gas in Molecular Sieve Dehydration Plant

关键词:  高含硫天然气  分子筛  脱水  吸附  再生  H2S

Key words:  high sulfur natural gas  molecular sieve  dehydration  adsorption  regeneration  hydrogen sulfide

摘要:

土库曼斯坦一大型高含硫天然气处理厂共有4列装置,设计每年可生产优质产品天然气50×108 m3。该厂原料天然气中H2S含量为2.942%(y),水含量为0.123%(y),经过脱硫、脱水、脱烃后产品天然气中H2S含量小于7mg/m3,水露点在5.6MPa(G)下可达到-21℃。该厂脱水单元采用4塔分子筛脱水工艺,自动化程度高,脱水深度完全能够满足设计要求,但在运行中发现脱水再生气中H2S含量较高。通过分析已找到再生气中H2S含量随再生时间和再生气量的变化规律,并通过延长再生时间和降低再生气流量等措施,降低了再生气中H2S含量,取得明显的效果。

Abstract:

There are 4 sets of units in a large high-sulphur natural gas processing plant in Turkmenistan,the designed treatment capacity of which is 5 billion cubic meters high-quality commercial natural gas each year.Sour natural gas processed in plant contains 2.942%(mol) hydrogen sulfide and 0.123%(mol) water.After desulfurization,dehydration and dehydrocarbon,H2S content will be reduced to less than 7mg/m3 and water dew point can be down to-21℃ under 5.6 MPa(g).Using 4 towers molecular sieve dehydration technology with high automation,the dehydration unit of this plant can meet the design requirements completely.However,it is found that H2S content of regeneration gas in dehydration unit is relatively high in this process.The change discipline of H2S content with the change of regeneration time and regeneration gas volume was found through analyzing,and some measures(such as extending the regeneration time,lowing the regeneration gas volume) were proposed to reduce the hydrogen sulfide content in regeneration gas.Facts show that these measures have remarkable effect.