1.8Mt/a催化汽油加氢脱硫装置的设计与开工

兰州石化公司炼油厂1.8Mt/a汽油加氢脱硫装置,采用法国AXENS公司的Prime G+固定床选择性加氢脱硫工艺。选择性加氢反应器采用HR-845S催化剂,加氢脱硫第一反应器采用HR-806S催化剂,第二反应器采用HR-841S催化剂,采用的催化剂活度高、选择性和稳定性好,在保证脱硫水平的同时,使辛烷值损失最低。因催化剂对进料杂质的限制,该工艺对原料油过滤精度、缓冲罐气封用气种类,较常规加氢精制装置严格。催化剂器外再生,干法硫化,循环氢系统设置脱硫塔,下游无需设置脱硫醇装置。该工艺的典型控制方案,如循环汽油流量控制、选择性加氢氢油比控制、分馏塔轻汽油抽出双串级控制等成熟可靠。在开工初期原料中的硫含量、烯烃含量较大偏离设计值时,通过调整氢气用量、反应器入口温度、轻重汽油切割点等工艺参数,仍能保证产品的质量指标。

Design and Start-up of 1.8Mt/a FCC Gasoline Hydrodesulfurization Unit

Lanzhou Petrochemical Company Refinery′s 1.8Mt/a gasoline hydrodesulfurization unit uses French company AXENS′ Prime G＋ fixed-bed selective hydrogenation desulfurization technology.The selective hydrogenation reactor uses HR-845S catalyst;the first hydrogenation desulfurization reactor uses HR-806S catalyst and the second reactor uses HR-841S catalyst.The catalysts used are characterized by high activity and good selectivity and stability.They can minimize the loss of octane number while ensuring the efficiency of desulfurization.As the catalysts have a limitation on the level of impurities in the feedstock,this technology has a stricter requirement for the filtering precision for the feed oil and the type of gas used as gas seal for the buffer tank than conventional hydrotreating units.In this technology,catalysts are regenerated outside the reactor;the dry method is used for vulcanization;and the circulating hydrogen system is equipped with a desulfurization tower,thus eliminating the need for a downstream sweetening device.The typical control schemes of this technology are mature and reliable,such as circulating gasoline flow control,hydrogen/oil ratio control for selective hydrogenation and double cascade control for naphtha extraction from the fractionating column.Even when the contents of sulfur and olefin in the feedstock greatly deviate from the design values in the initial stage of production of the unit,the quality of products can still meet preset specifications through the adjustment of technological parameters such as the amount of hydrogen used,the inlet temperature of reactors and the cut points for light and heavy gasoline.