解决焦化装置结焦的有效技术措施

兰州石化公司120×10^4t／a延迟焦化装置焦炭塔顶经常出现油气线结焦而使塔压升高的问题，使装置的生产能力受到一定的限制；焦化馏出口产品携带一定量焦粉，影响产品质量，同时焦炭塔顶部大油气进入分馏塔底部，也加剧了分馏塔底部及其管线结焦，致使清焦过于频繁。通过分析后，将焦炭塔顶部急冷油由直接三点式注入改为在大油气线内增设环形分配器注入，阻焦剂的位置从加热炉人口移至分馏塔底部。这两项措施实施后，焦炭塔顶部压力均值由1．65MPa降至1．56MPa，大油气线压力也相对下降，大油气线结焦得到缓解；分馏塔底循环油泵的流量由5t／h提高到20t／h，缓解了塔底结焦倾向，塔底管线及过滤器清焦周期由一周延长至一个月；加热炉生产负荷由48t／h提高到52t／h，装置循环比由0．35～0．4降至0．23～0．28，提高了装置的生产能力：每年可多产生经济效益831．153万元。

Solution to Coke Deposition in Coking Units

PetroChina Lanzhou Petrochemical Company＇s 120×105/a delayed coking unit frequently suffered pressure buildup in the coking column due to coke deposition in the oil-gas lines at the top of the coking column.This had hamstrung the unit＇s production capacity.Products from the eoking distillation outlet contain some powdered coke which affected the quality of products produced.The entry of oil and gas from the oilgas lines at the top of the coking column into the bottom of the fractionating tower also exacerbated the coke deposition at the bottom as well as in the pipelines of the fractionating tower,requiring frequent coke removing operations.After analysis ,technicians changed the method of injecting coking column,from direct injection through three points to injection through quenching oil at the top of the a ring distributor added in the oil-gas lines,and moved the position of anti-coking agent to the bottom of the fractionating tower from the inlet of the heating furnace.With the adoption of these two measures,the average value of pressure at the top of the coking column dropped to 1.56MPa from 1.65MPa and the pressure on the oil-gas lines also dropped, resulting in an alleviation of coke deposition in the oil-gas lines.The flow rate of the circulating oil pump at the bottom of the fractionating tower increased to 20t/h from 5t/h and as a resuh the coke deposition at the bottom of the tower was eased.The cycle of coke removal for the pipelines at the bottom of the fractionating tower and the filter extended to one month from one week;the production load of the heating furnace rose to 52t/h from 48t/h;the recycle ratio of the unit dropped to 0.23-0.28 from 0.35-0.4.With the increase of the unit＇s production capacity,annual economic returns from the unit increased by 8.31153 million Yuan.