Simulation of industrial-scale gas quenching process for partial oxidation of nature gas to acetylene

Abstract

In the water quenching process for partial oxidation (POX) of nature gas to acetylene, the temperature of the product gas mixture directly decreases from about 1800K to 360K, thus the heat cannot be recovered. To overcome this problem, a new gas quenching process of jet-in-cross-flow (JICF) was proposed for the partial oxidation (POX) process to enhance the energy efficiency. The computational fluid dynamics (CFD) coupled with detailed chemistry was employed to simulate the mixing and quenching performance in an industrial-scale JICF reactor. Both the Probability Distribution Function (PDF) and Eddy Dissipation Concept (EDC) models were used to compute the chemical source term, and the PDF model predicted a higher acetylene loss. The uniform index (UI), temperature, species concentrations and acetylene loss were investigated during the quenching process. Using the PDF, the optimum main/jets flow mass ratio was determined as 2.59, at which the loss percent of acetylene was about 3wt%. The simulation results show that the gas quenching process is very attractive because the heat can be effectively recovered after the quenching at a cost of slight loss of acetylene.