Methanol synthesis from syngas obtained by supercritical water reforming of glycerol

A process for producing methanol from the synthesis gas obtained by reforming of glycerol using supercritical water is studied. The process also produces power from the huge pressure energy of product gas just at the outlet of the reformer by a turbine. The expanded product gas is conditioned in a PSA system, which has three sections so as to produce a H2-rich gas stream, a CO-rich gas stream and CO2 for sequestration. Thus, it can be achieved the feed required for the methanol synthesis. The surplus hydrogen is sent to a fuel cell to generate power, and the PSA off-gas, purge from the methanol loop and gases separated from the crude methanol are burnt in a furnace to achieve an energy self-sufficient process. By changing the reforming temperature, the water-to-glycerol mass ratio and the purge from the methanol loop, the conditions for optimizing the overall process relative to methanol and power productions were achieved. Thus, by reforming at 1000 °C and 240 atm, and performing the methanol synthesis at 250 °C and 85 atm, the optimal conditions were a water-to-glycerol mass ratio of 1.68 with a purge ratio of 0.2. Under these conditions 0.270 kg MeOH/kg glycerol and overall energy efficiency of 38.0% were obtained. The separated CO2 for sequestration is 0.38 kg/kg of glycerol.