Yangzi Petrochemical Company—the First One in China to Adopt UOP’s Novel Aromatics Adsorbent

The Yangzi Petrochemical Company is the first one among domestic aromatics manufacturers to adopt the UOP’s latest novel adsorbent during quality upgrading of its No. 2 xylene unit. On October 23, 2013 this unit has been continuously delivering xylene product with a purity of 99.86%, which is better than the expected purity target of 99.7% coupled with a significant energy reduction, making its unit more technically advanced over domestic peers. Furthermore, this unit has increased its production capacity by over 30%.

The technical revamp of this xylene unit intends to improve operating economics and product quality. During the revamp, which spanned 100 days, the existing adsorbent was replaced with the latest novel adsorbent ADS-47, and the downstream fractionation unit was modified correspondingly with the trays in raffinate tower and the deheptanizer replaced with high-efficiency trays and reboilers. In the meantime, the rotary valves of key equipment were retrofitted with high-efficiency ones, resulting in an increase of adsorption efficiency exceeding 97% from the original figure of 95%.

Currently the operating status of xylene unit has demonstrated that the pressure differential in adsorbent beds is stable, and the rotary valves work smoothly, resulting in remarkable improvements in separation efficiency and throughput of the fractionation column. The operation of this unit has indicated that under the same load the recycle flow rate has been reduced by nearly 30% to greatly decrease the energy consumption of #2 xylene unit with the product purity raised to over 99.7% from the previous figure of 99.5%.