Phase stability analysis on green methanol synthesis process from CO2 hydrogenation in water cooled, gas cooled and double cooled tubular reactors

Abstract Tackling environmental crisis and fossil fuel depletion is one of the major concerns in today's world. Among all the techniques of CO 2 mitigations, its conversion to value-added materials such as methanol, is of a great interest. A detailed phase stability analysis was implemented in the modeling of methanol synthesis process from CO 2 and H 2 mixture in three proposed configurations with different cooling systems, namely water cooled, gas cooled and double cooled reactors. This paper aims to present and compare the capability of each configuration in converting CO 2 to methanol (hydrogenation process) by focusing on thermal behavior, possibility of second phase formation and effect of inlet pressure (5–30 MPa), inlet temperature (480–550 K) and CO 2 /CO molar ratio (0.25/0, 0.20/0.05, and 0.15/0.10). To this end, phase equilibria were applied to the mathematical modeling of each configuration in order to examine the possibility of the existence of a condensed phase. A modified version of Soave−Redlich−Kwong (SRK) equation of state (EOS) was used to correct the association effects (e.g., hydrogen bonds). The results revealed that at similar conditions the gas cooled reactor leads to higher CO 2 conversion and methanol yield than the other two configurations, and the liquid phase does not form in this type of reactor. Furthermore, the feedstock is preheated in the inner tubes of gas cooled reactor surmounting the need for the feed gas preheater.