不停工处理再生滑阀问题的探讨

采用双提升管的催化裂化(FCC)装置再生滑阀出现故障后,欲实现不停工处理,关键有二:一是建立新的催化剂循环系统,二是以装置压力平衡和热平衡为重点进行操作调整,满足正常运转需要.确保压力平衡的关键,是沉降器快分在最低线速以上运行,沉降器藏量能够自动调节,气压机人口压力不低于机组自保启动值.为此,需要降低原料油流量到设计负荷的50％～60％,提高预提升干(富)气流量至其上限值,即6000m3/h(标准),降低气压机转速,提高其返喘振流量；其后,根据热量平衡,提高汽油提升管反应温度至600℃,选择合适的汽油回炼量,并适当降低再生器主风供给量.当压力平衡得到满足后,使用燃烧油,确保供热链的正常,停用外取热设施,提高装置掺渣比,适当降低再生催化剂温度.2010年2月5日,长岭石化1号FCC装置再生滑阀盘根箱发生催化剂严重泄漏,采取关闭再生滑阀的方法进行堵漏.利用汽油提升管反应后的待生催化剂,通过待生循环滑阀改进重油提升管,建立新的催化剂循环,历时7h,成功做到不停工处理再生滑阀问题.

A Discussion on No-shutdown handling of Regeneration Sliding Valves

To handle a failed regeneration sliding valve of an FCC unit equipped with dual risers without shutting down the unit,two key steps must be taken:Firstly,establishing a new catalyst circulation system;and secondly,optimizing operation with the emphasis on pressure and heat balance of the unit to meet the need for normal operation.The key to maintaining a pressure balance is to ensure that the quick separator of the precipitator operates at a speed higher than the lowest linear speed,the catalyst inventory of the precipitator is self-adjustable,and that the pressure at the inlet of the aerostatic press is not less than the unit’s self-protection startup value.To achieve this objective,the flow of the feedstock oil must be reduced to 50%-60% of the designed load,the flow of the pre-lifted dry(rich) gas must be raised to the maximum value,i.e.,6000m3/h(standard),the speed of the aerostatic press must be lowered and its return surge flow must be raised.Follow-up measures include,based on heat balance data,raising the temperature for reactions in the gasoline riser to 600℃,selecting the appropriate volume of gasoline recycled,and reducing the main air supply for the regenerator to an appropriate extent.When the pressure balance is achieved,fuel oil is used to ensure a normal heat supply chain.The external heat exchange facility is shut down,the slag mixing ratio of the unit is raised and the temperature of recycled catalyst is reduced to an appropriate extent.On February 5,2010,a serious catalyst leak took place in the packing box of the regeneration sliding valve of the FCC unit No.1 of Sinopec Changling Company.The regeneration sliding valve was shut down to block the leakage.Technicians used the catalyst to be regenerated after reactions in the gasoline riser and the to-be-regenerated catalyst circulation sliding valve to optimize the heavy oil riser and establish a new catalyst circulation.The regeneration sliding valve was successfully repaired without shutting down the unit.The work lasted seven hours.