| This paper aims to develop a new process for liquid-phase methanol (LPMEOH) synthesis feeding with coal gasification syngas (H2/CO=0.68) or heavy oil cracking syngas (H2/CO=0.9). Both are poor H2 material gas, can't be directly to apply for the low and middle pressure gas-phase process widely used currently, so a lot of H2 has to be supplied to match the need of H2/CO=5-10:1, and make the cost greatly increased. The necessity for developing liquid-phase process is more important.Based on a few useful parameters obtained from U.S. department of energy website, a new process flow diagram (PFD) was design for liquid-phase methanol synthesis, and then process parameters were calculated with ASPEN PLUS, a famous chemical process simulation software, some modification and optimization were developed. Then the pipeline and instrument flow diagram (P & 1D) was finished. The investment cost and operating cost were estimated, and environmental problem was discussed.One of the most difficult design problems is removing the heat of reaction while maintaining precise temperature control. In this design, slurry bubble column reactor (SBCR) was used, CuO-ZnO-Al2O3 fine catalyst particles slurried in an inert mineral oil. The catalyst is kept in suspension by reactant gas, which bubbles up through the catalyst slurry. The mineral oil acts as a temperature moderator and a heat removal medium, transferring the heat of reaction from the catalyst surface to boiling water in an internal tubular heat exchanger. As a result of its capability to remove heat and maintain a constant uniform temperature throughout the reactor, the SBCR can achieve a much higher syngas conversion per pass, compared to a gas-phase reactor.Desired methanol production rate is 500 t/d, and actual rate is 477 t/d and 544 t/d when total feed flow is 4,200 kmol/hr, in which H2/CO ratio is 0.68 and 0.9 separately. Under the operating condition of 235℃temperature and 51 bar pressure for reactor, CO conversion is 30% and 38% separately. The H2 content in unreacted gas is so low that do not need to be cycled, and unreacted gas directly sent to the fuel head.Liquid-phase process consists of some unit, such as heat exchanger, reactor, gas-liquid separator, cyclone separator and distillation etc.. An inner heat exchanger network and water heat exchanger network was finished by heat integration. aims to recover heat and reduce cost. Three liquid-vapor separators, at pressure of 50 bar,48 bar and 2 bar were used to separate gas from crude methanol. Two-stage distillation tower was adopted to separate dissolved gas from crude methanol and refined pure methanol from bottom stream. Calculation results show that the same set of equipments can be used to two different composition syngas at same feed flow.Investment cost estimation indicates that the total investment is￥196,810,000, lower than the gas-phase process. And operating cost is￥24,641,200/yr. Return on investment (ROI) is 113.7% and payback period (PBP) is 0.54 years.
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