Synthesis of alcohols from syngas

Abstract

A through-flow high-pressure reactor that can withstand up to 100 atg at 400℃ was designed and constructed. Three Types of catalysts, Rh1Mn1Fe0.1/SiO2, Co1Ba0.05Ag0.1/SiO2 and Co1Cu1Cr0.9K0.096’ were prepared for the investigation of alcohol synthesis from syngas. The experiments on alcohol synthesis were carried out mainly with the feed ratio of Co to H2 = 1.25:1. In addition in the case of Rh1Mn1Fe0.1/SiO2, the feed ratio of Co: H2 at 1:2 was also investigated. The temperatures that were investigated in this work were 250,280,310 and 340℃. The pressures that were investigated for the effect of pressure ranged from 40 to 80 atg with the GHSV = 2,000 hr-1. In the case of the Rh1Mn1Fe0.1/SiO2, catalysts, the effect of GHSV was investigated in the range of 1,000-8,000 hr-1 at the pressure of 80 atg. In the case of the Co1Ba0.05Ag0.1/SiO2 and Co1Cu1Cr0.9K0.096 catalysts, the GHSV was varied from 1,000 to 4,000 hr-1 at 80 atg and 75 atg, respectively. The best global results for STYELOM and STYtot.nls.were obtained with the Rh1Mn1Fe0.1/SiO2, catalyst at P = 80 atg when the GHSV was 8,000 hr-1 and the temperature at the feed retio of CO:H2. The values were 2.85 mole ethanol/lit.cat.-hrand 4.975 mole alcohol/lit.cat.-hr, respectively. In the case of Rh1Mn1Fe0.1/SiO2, catalyst, it was fourmed at P = 40 atg that as reaction temperature increased, the space time yield of alcohols was increased. On the other hand, it was found that at the highest pressure, the space time yield of ethanol synthesis was most favorable, especially at the highest GHSV. This might be concluded that for ethanol synthesis, an higher pressure and an higher temperature, and a shorter contact time were most favorable. It the temperature was very high and the contact time was long, an increase in the combustion of intermediate products would result. This was evident in the case of the feed ratio of CO:H2 = 1.25:1. It was found that the case of the feed ratio of CO:H2 = 1:2 yielded better results in alcohol synthesis and less combustion products than the case of CO:H2 = 1.25:1. In the case of the Co1Ba0.05Ag0.1/SiO2 and Co1Cu1Cr0.9K0.096 catalysts, the space time yield of alcohols that was obtained was generally less than that in the case of the Rh1Mn1Fe0.1/SiO2 catalyst. The effect of pressure on the alcohol synthesis showed a similar trend to the Rh1Mn1Fe0.1/SiO2 catalyst. Generally there is an optimum temperature for STYtot.als.within the range of temperature investi gated, while the effect of GHSV on the alcohol synthesis was not quite clear.