Some blocking problems emerged in pipelines of the sulfur recovery unit with a capacity of 4 kt/a after it was put into operation,which seriously affected the production.In this unit,the Clause sulfur recovery process of high-temperature thermal reactions and the two-stage catalytic reactions are applied.With the instrument automatically controlling the air flowrate,the ratio of the unconverted H2 S to the SO2 generated in combustion reactions is kept at 2∶ 1.When the composition of the feed gas and the flowrate fluctuate dramatically,the incomplete combustion of hydrocarbons occurs as the air is insufficient because of the delay of the air distribution adjustment.Thus the CO and C are generated,which can react with SiO2 or silicates to generate Si and SiO.When the air flowrate is increased,Si and SiO are oxidized to SiO2,which then sticks to the furnace wall and surface of pipes as well as internal wall of the mixing valve and pipes and finally results in the blocking.Taking of effective measures to reduce dusts in the wind,strict control of the hydrocarbons in the feed gas,maintenance of stable operation of combustion furnace of sulfur unit can effectively prevent the sulfur manufacturing system from SiO2 blocking.%某4 kt/a硫磺回收装置投产后,制硫余热锅炉管束及其后部系统出现堵塞,严重影响生产.该装置采用高温热反应和两级催化反应的克劳斯硫回收工艺,用仪表自动控制配风量,以控制炉内未转化为硫的H2S与燃烧生成的SO2摩尔比保持在2∶1.当原料气的组成和流量发生大幅度波动时,由于配风量调节滞后,当风量不足时,发生烃类的不完全燃烧,出现还原性气氛,产生CO和元素C,与SiO2或硅酸盐类反应,生成元素Si和SiO.当风量相对提高时,Si和SiO又氧化为SiO2附着于炉壁、掺和阀和管壁上,造成堵塞.采取措施降低风中含尘量、严格控制原料气中的烃含量、保持制硫燃烧炉平稳操作,能有效避免制硫系统SiO2堵塞.
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