“Packaged Technology of 120 kt/a Energy-Saving Styrene Unit” and Other Three Styrene Related Projects Passed Review and Appraisal

On December 10, 2013 “The packaged technology of 120 kt/a energy-saving styrene unit” and other three styrene related projects jointly undertaken by the SINOPEC Shanghai Petrochemical Research Institute and other relevant institutions had passed the review and appraisal organized by the SINOPEC Science and Technology Division. Upon submittal of proposal for working out the package technology of energy-saving production of styrene, much attention was referred to the high energy consumption of styrene unit and the major efforts were aimed at key equipment and techniques, including the sequential separation of products, the recovery of azeotropic heat, the energy-saving rectification technology, the thin-bed dehydrogenation reactor, the mixer, and heat-exchangers for azeotropic heat recovery. This technology has been for the first time applied in the commercial 120 kt/a styrene unit at the Baling Petrochemical Company starting June 2012, with the unit brought on stream at the first attempt successfully. The outcome of running this styrene unit for one year has revealed that this technology can save over 20 % of energy, resulting in lower temperature in ethylbenzene/styrene tower kettle, lower polymerization loss, more stable operation to display the outstanding overall economic benefits. The relevant institutions have applied for 17 China invention patents, among which 11 patents with innovative nature and independent intellectual property rights have been granted.

The project “Technology for optimized operation of styrene production process and its industrial application”has also passed the appraisal. This project after study has established the process models covering the alkylation reaction of benzene with ethylene, the transalkylation reaction, the separation of alkylates, the dehydrogenation of ethylbenzene and the separation of dehydrogenated products, with these models being checked against the actual operating data of the 200 kt/a ethylbenzene/styrene unit at the Qilu Petrochemical Company. The established process models can reliably describe the actual operating status of a commercial styrene unit, and the calculation and simulation results based on the whole process scheme have verified the good projection precision of these models. The outcome of operation of styrene unit have indicated that the optimization of operating parameters can reduce the steam consumption by 2.6% during dehydrogenation of ethylbenzene, decrease the steam consumption by 2.7% in the course of separation of alkylation products, and reduce the steam consumption by 2.1 % in the dehydrogenation process.