Staging of di-methyl-ether (DME) synthesis reactor from synthesis gas (syngas): Direct versus indirect route

Abstract

Di-methyl-ether (DME) has been received much attention because of its key features. It can be produced from any carbon-rich feedstock through the conversion of carbonaceous material to synthesis gas (syngas) and then to DME via indirect or direct route.In the current paper, the DME reactor is modeled and the effect of reactor staging on the reactor productivity and a measure of annual profit is investigated. Different number of stages, inlet syngas composition, and direct/indirect DME synthesis routes from syngas was considered.For the direct DME synthesis with an inlet syngas H2/(CO+CO2) of 2.33 and maximization of DME production as the objective function, staging of a DME reactor (with total volume of 100m3) to two and three stages increases the reactor productivity by 23.4% and 26.9%, respectively. In each case, the volumes of stages are included in the optimization. If the volumes of stages set to be equal (2×50m3 or 3×33.33m3), the reactor productivity of the two- and three-stage systems becomes 17.3% and 22.5% higher than the single-stage reactor. When the inlet H2/(CO+CO2) is set to 1, sectioning the DME reactor to stages increases the reactor productivity as well.For the indirect DME production route, the optimization results indicate that the DME production rates of the two- and three-stage cases are lower than the direct route.The profitability index of the two- and three-stage reactor systems is 65.53% and 72.35% higher than the single-stage reactor. This is because of higher DME production and lower heat transfer area requirement of the staged configurations.