Simulation of low-temperature coal tar hydrocracking in supercritical gasoline

The aim of this paper was preliminary design of the process for low-temperature coal tar hydrocracking in supercritical gasoline based on Aspen Plus with the concept of energy self-sustainability. In order to ensure the correctness and accuracy of the simulation, we did the following tasks: selecting reasonable model compounds for low-temperature coal tar; describing the nature of products gasoline and diesel accurately; and confirming the proper property study method for each block by means of experience and trial. The purpose of energy self-sustainability could be possibly achieved, on one hand, by using hot stream to preheat cold stream and achieving temperature control of streams, and on the other hand, by utilizing gas (byproduct of the coal tar hydrocracking) combustion reaction to provide energy. Results showed that the whole process could provide a positive net power of about 609 kW·h for processing the low-temperature coal tar with a flowrate of 2 268 kg/h. The total heat recovery amounted to 2 229 kW-h, among which 845 kWh was obtained from the gas combustion reaction, and 1116 kW-h was provided by the reactor's outlet stream, with the rest furnished by hot streams of the products gasoline, diesel and residue. In addition, the process flow sheet could achieve products separation well, and specifically the purity of product gasoline and diesel reached 97.2% and 100%, respectively.