Aromatic Complex Unit Energy Saving Transformation

The aromatic complex unit of Sinopec Luoyang Company has several units, suchas aromatic Extractive Distillation (ED) unit, benzene ED unit and paraxylenecomplex unit, of which the most important are aromatic ED unit and paraxylenecomplex unit. The aromatic ED unit includes the feed prefractration，the aromatic ED,BT distillation and solvent oil unit. It adopt the UOP sulfolane process, the feed isreformate oil and the products are benzene, toluene,6#ED solvent oil and solvent oilwhich is used in rubber industry, the throughput is260000tons per year (calculatedby ED feed) and was put into operation in February of2000. The paraxylene complexunit was introduced from BABCOCK Company of England and it adopted the UOPtechnology; it has four units, disproportionation and alkyl transfer unit, xylenedistillation unit, isomerization and adsorption separation unit. The purity of theproduct paraxylene is99.8%and meanwhile, it can produce some benzene, the designscale is160000tons paraxylene per year. To adapt to changes in feedstock anddownstream demand for the feed, according to the advisory opinion of the PX unitcapacity expansion from Sinopec technology committee, the unit capacity expansionwas carried out in two stages., the PX unit standard transformation was completed in2003, domestic HAT-097disproportionation catalyst was changed and the unit wasupgraded to eliminate the defects, the PX output has reached180000tons/year. Thesecond phase of the transformation was carried out in2005, the isomerization catalystand adsorbent is replaced, a new157000tons/year (take pre-fractionation feed as astandard) benzene ED unit was built, additional OX product tower and relatedfacilities was also built and OX products extract was increased. Through twotransformations, PX production capacity has reached215000tons/year, OXproduction has reached33300tons/year in2007, the PX actual production hasreached242100tons/year, and the production of benzene, toluene and o-xylene hasarrived at401200tons/year. First, this paper analyzed the status of aromatics complexunit, then combined the equipment characteristics, and finally proposed somecorrective measures and plans for the distillation column and furnace energy-savingof the aromatics complex unit. What’s more, some comparisons were made before andafter the energy optimization.