Study of the effect of process conditions on the Methanol production

The production of Methanol from natural gas feedstock is one of the most important gas-to-liquid processes which can be divided into four main stages: feed purification, reforming, methanol synthesis and methanol purification. The light ends present in the raw methanol are removed in the topping column. The stabilized raw methanol consisting of methanol, water and minor amounts of higher alcohols is fractionated in the purification section to produce methanol grade AA.The optimization of the purification section is the subject of the present work.The goal is to maximize the amount of final MeOH of AA gradein which,the concentration of methanol is above 99.85(%wt).The simulation program Aspen Plus®, was used to construct the process model and optimize the product specifications. The effect ofdifferent parameters to optimize the columns of the purification section has been investigated, such as thechange in reboiler duty, the feed stage and the off gas temperature for thetopping column, whilereflux ratio, side stream flow rateand reboiler duty are the variables which have been optimized in therecovery column.According to the simulation, the total methanolloss of 432.814kg/hr was estimated and with optimum conditions the amount of methanol in the final product was 209115.74 kg/hr. The optimized distillate rate and reboiler duty of the topping columnare 79.8 (kmol/hr) and 38.83481(MMkcal/hr), respectively. The optimumreflux ratioofthe recovery columnwas obtainedwhich is2.23.