炼油厂酸性水原料罐恶臭气体综合治理新方法

New comprehensive treatment method of effluvial gas of sour water feed tanks in refineries

关键词:  酸性水原料罐  污染治理  酸性水脱气罐  循环液缓冲罐  油封  H₂S  氨 

Key words:  sour water feed tanks  pollution treatment  sour water degassing drum  temperature  pressure  recycle liquid surge drum  oil seal  H₂S  ammonia

摘要:

提供了一种对酸性水原料罐排放气污染进行综合治理的方法。该法不同于以往的吸附法、吸收法或冷凝法,而是根据酸性水汽提装置的工艺特点,通过改变工艺流程和操作条件,最大限度地降低酸性水原料罐中易挥发组分的浓度,实现污染治理。主要措施包括:①将酸性水脱气罐操作压力降低到0.05～0.10 MPa；②用汽提塔塔底净化水的低温余热将进酸性水脱气罐的酸性水加热至55～60 ℃,使酸性水脱气罐在较高的操作温度下操作；③将单塔汽提中的一、二、三级分凝液或双塔汽提中的氨汽提塔塔顶回流罐的液相返回物流送入一个循环液缓冲罐中,然后用泵升压并送至酸性水原料泵出口的酸性水管线上；④将酸性水原料罐中油层厚度适当增加至600～900 mm,形成油封,以有效地阻止H₂S等恶臭气体组分从酸性水原料罐中逃逸等。上述措施实施后,酸性水原料罐在正常操作状态下无恶臭气体排出。该法具有不需要外部的吸附剂、吸收剂或冷冻剂,投资及运行费用低,操作简单,没有二次污染的优点。 

Abstract:

This article provides a comprehensive treatment of the effluvial gas of sour water feed tanks. Different from normal treatment such as adsorption, absorption or condensation, and based on the process characteristics of sour water stripper, this method decreases the volatile components content maximally by changing process flow and operating conditions. The main measures include:① The operating pressure of sour water degassing drum is kept as low as possible (0.05-0.1 MPa); ② Sour water in degassing drum is heated to 55-60 ℃ using low temperature waste heat of purifying water from the stripping bottom to make the degassing drum operated in higher temperature. ③ The first, second and third stage condensate liquid in single stripping tower or the return liquid from ammonia stripping reflux drum in double stripping tower is sent to a recycle liquid surge drum, and then is pumped to the outlet pipe of sour water feed pump; ④The thickness of oil layers in sour water feed tanks increases to 600-900 mm to form oil seal, preventing H₂S or other effluvial compounds running out of the sour water feed tanks. After the above measures are taken, there would have no effluvial gas discharging from the sour water feed tanks in normal operating conditions. This method has several advantages, such as no need of additional adsorbent, absorbent or coolant, low investment and operation cost, simple operation and no secondary pollution.