Process Design, Economic Optimization, and Environmental Assessment for the Production of Glycerol Carbonate via Reactive Distillation Combined with Pervaporation

Abstract

In this study, a reactive distillation (RD) coupling pervaporation (PV) process was introduced to intensify the transesterification of dimethyl carbonate (DMC) with glycerol to produce glycerol carbonate. The yield of glycerol carbonate can be increased to more than 99.5% due to the timely removal of the by-product methanol. The PV module was used to recover DMC in the azeotrope (DMC/methanol) from the RD column. In addition, another RD process using pressure swing distillation (PSD) to recover DMC was simulated as a comparison. The design variables of both processes were optimized to obtain the lowest total annual cost (TAC), and the greenhouse gas emissions of the two processes were compared. Ultimately, in comparison to the RD-PSD process, the TAC of the RD-PV process was reduced by 18.67%, and the emissions of CO2, SO2, and NO x were reduced by 29.34, 29.52, and 29.52%, respectively.

Sustainable Glycerol Carbonate Manufacturing: Process, Synthesis, Design, and Control

“…Aspen plus dynamics is used for steady-state and dynamic process modeling. To benchmark against the most recent process designs developed by Sun et al, 18 the steady-state design is developed for an identical GC product rate and purity of 10 kmol/h and 99.64 mol %, respectively. Also, an identical MeOH coproduct purity of 99.5 mol % is used.…”

“…In this section, the economic and sustainability metrics for the proposed flowsheet design are compared with those for the existing RD pervaporation (RDPV) flowsheet developed by Sun et al 18 and the RD extractive distillation (RDED) flowsheet developed by Yu. 16 The RDPV flowsheet, shown in Figure 6, is structurally similar to our proposed flowsheet except for replacing the LP MeOH coproduct recovery column with a pervaporation unit that recovers pure methanol as the permeate and recycles the MeOH-rich retentate back to the RD column.…”

“…The finally recommended near-optimum nominal design and operating conditions are shown in Figure 4. Note that the product column base temperature is 253 °C, similar to that in the design by Sun et al 18 so that hot oil at 300 °C is used as the heating utility. The size of the major equipment and its capital and operating cost are summarized in Table 4.…”

“…The latter is shown to be significantly cheaper. Sun et al 18 exploit the pressure sensitivity of the MeOH−DMC azeotrope 19 in a pressureswing distillation (PSD) sequence to bypass the MeOH− DMC azeotrope and recover a pure MeOH coproduct. The process flowsheet consists of an RD column, followed by three simple distillation columns.…”