液化石油气醇胺法脱硫抽提塔的设计

Design of LPG extraction tower for desulfurization by alkanolamine method

关键词:  醇胺法  抽提塔  填料  筛板塔  直径分布器  孔径  聚结器  活性炭  流量设计

摘要:

目前,醇胺法净化装置液化石油气抽提塔广泛采用填料塔或筛板塔。重点探讨了填料塔、筛板塔设计方面的一些内容。对于填料塔,给出了填料层高度、塔径、分布器、再分布器计算或估算的方法,提供了散堆填料和规整填料所要求的最低胺液与LPG流量比值；对于筛板塔,给出了筛孔孔径和过孔速度、分散相操作线速、板间距、塔直径计算或估算方法,提供了典型的分散相进料设置方式及处理两相体积流量比过低工况的筛板塔结构。提出了一种对LPG抽提塔进料进行综合处理的措施:即LPG进料管道上设置聚结器,脱除LPG中水溶性有害物质；在贫胺液管线上设置包括一级过滤器、活性炭过滤器、二级过滤器在内的过滤系统,脱除贫胺液中杂质。指出了活性炭过滤器能有效吸附溶于胺液中的可溶性有机物污染物,提出以下建议:①经活性炭过滤器处理的贫胺液体积流量为贫胺液总量的15%~25%；②胺液在活性炭床层内的停留时间不少于15 min；③活性炭过滤器按一开一备进行设计。 

Abstract:

At present, the packing or sieve tray is widely used in the LPG extraction tower of the alcohol amine purification unit. This paper focuses on the design of packing tower and sieve tower. For the packing tower, the packing height, tower diameter, distributor, redistributor calculation or estimation methods were given, and the minimum amine to LPG flow ratio required by random packing and structured packing was provided. For the sieve tray tower, the methods of calculating or estimating the sieve hole diameter and the velocity through the holes, the operating linear velocity of dispersed phase, the tray spacing and the tower diameter were given. The typical dispersed phase feed setting mode and the structure of the sieve tray column dealing with low volume flow ratio of two phases were also provided. A comprehensive feed treatment measure for LPG extraction tower was put forward, which is the LPG coalescer was used to remove the water-soluble harmful substances from LPG, and a filtration system, including primary filter, activated carbon filter and secondary filter, was installed to remove impurities from the lean amine pipeline. It was pointed out that activated carbon filter could effectively adsorb soluble organic pollutants dissolving in amine solution. The suggests were as follows:(1) the amount of lean amine treated by activated carbon filter was 15%-25% of the total amount of lean amine circulation rate; (2) the residence time of amine solution in the bed of activated carbon should not be less than 15 minutes; (3) the activated carbon filters were designed according to one for operation and one for preparation.