Study on Guo V diesel upgrading

Emission standard of motor diesel has become increasingly stringent with eminent environmental protection problems. Guo Ⅲ diesel with sulfur content of 350 ppm is implemented in most part of China while Guo Ⅳ diesel with sulfur content of 50 ppm is sold only in some areas. The refineries in China have faced a great challenge of upgrading the diesel to Guo Ⅴ standard with sulfur lower than 10 ppm. The possible problems are discussed in view of the tendency and urgency of diesel upgrading. Upgrading revamping of diesel hydrotreating units is recommended for the production of Guo Ⅴ diesel,which mainly includes replacing high-activity desulfurization catalysts,uniform catalyst loading,adjusting the overall process configuration to provide better feedstock like straight-run( SR) diesel,increasing the reactor catalyst volume,raising reactor operating temperature,replacing with the high-efficiency reactor internals,adding recycle hydrogen desulfurization system,etc. Meanwhile the probable bottlenecks in the upgrading revamping of units are pointed out and the research trend is proposed.