固定床渣油加氢装置延长运转周期的改造实践

以中东高硫原油的常压渣油为原料，在反应器入口氢分压为14.5 MPa，氢油体积比为700，液时体积空速分别为0.20，0.30，0.40 h-1，反应温度分别为385 ℃和390 ℃的条件下开展中型加氢试验，结果表明，固定其他工艺条件不变时，降低空速可以提高产品质量或降低反应温度，从而延缓催化剂失活，延长运转周期。因此提出了增设反应器的措施，并在2套工业固定床渣油加氢装置上进行相应的改造实践，结果表明：A炼油厂在原固定床第一反应器前增设一台上流式反应器，装置总处理量由0.84 Mt/a增加到1.5 Mt/a，第九运行周期（RUN-9）加氢渣油硫质量分数低于0.5%，氮质量分数为0.2%～0.3%，金属（Ni＋V）质量分数低于15 μg/g，残炭为3%~5%，装置运转周期由240 d延长至480 d；B炼油厂在原固定床第二反应器后增设一台固定床反应器，装置体积空速由0.4 h-1降低至0.25 h-1，与改造前RUN-9相比、改造后第十二运行周期（RUN-12）的反应脱硫率略有增加，其降残炭率、脱金属率和脱氮率显著提高，装置的运转周期由335 d延长至518 d。

REVAMPING AND OPERATION OF FIXED BED RESIDUE HYDROTREATING UNIT FOR LONGER OPERATION CYCLE

The residue hydrotreating pilot tests were carried out at 14.5 MPa, 385 ℃ and 390 ℃, LHSV of 0.20，0.30，0.40 h-1, and H2/oil of 700, respectively, using the Middle-East high sulfur AR as feedstock.The results showed that the sulfur content，carbon residue，metal (Ni+V) content and nitrogen content of the hydrogenated oil were all reduced as the LHSV decreased under the other process conditions unchanged. Furthermore, two sets of industrial fixed-bed residue hydrogenation units were revamped. For refinery A，adding an upflow reactor in front of the original fixed bed first reactor made the capacity of the unit increase from 0.84 Mt/a to 1.5 Mt/a. During 9th operation cycle(RUN-9)，the sulfur content in the hydrotreated residue was less than 0.5%, nitrogen was between 0.2% to 0.3%，metal (Ni + V) content below 15 μg/g，and Conradson carbon residue between 3% to 5%. Time on stream（TOS）was prolonged from 240 d to 480 d. For refinery B，a fixed bed reactor was added after the original second reactor of the fixed bed system，the LHSV of the unit decreased from 0.4h-1 to 0.25 h-1. Compared with RUN-9 results before the revamp, HDS rate in RUN-12 was slightly increased，while the HDCCR rate，HDM rate and HDN rate were all significantly increased. TOS of the unit was prolonged from 335 d to 518 d.