Kinetics of the gas-slurry methanol-higher alcohol synthesis from CO/CO_2/H_2 over a Cs-Cu/ZnO/Al_2O_3 catalyst, including simultaneous formation of methyl esters and hydrocarbons

摘要

First kinetic results are presented for the gas-slurry methanol-higher alcohol synthesis from CO/CO_2/H_2 (syngas) over a Cu_(0.44)Zn_(0.43)Al_(0.12)Cs_(0.31) catalyst (particle size: 50-75 μm), slurried in n-octacosane. Experimental conditions varied as follows: pressure = 20-80 bar, temperature = 473-573 K, H_2/CO ratio in the feed = 0.53-3.38, mole fraction CO_2 in the feed = 0.026-0.037 and space velocity = 0.065 x 10~(-3)-1.395 x 10~(-3) Nm~3 s~(-1) kg_(cat)~(-1). Methanol was the major product. Further, higher 1-alcohols, 2-methyl-l-alcohols, methyl esters, n-parafflns, CO_2 and H_2O were formed. In contrast to observations in a gas-solid system, formation of 2-methyl-n-paraffins was negligible. From the same model, proposed earlier for the gas-solid systems B.B. Breeman et al., Chem. Eng. Sci., 49, 24A (1995), the product distributions of the alcohols, the paraffins and the methyl esters could be predicted with average relative deviations of 5.9%, 7.8% and 1.6%, respectively. The presence of n-octacosane as a slurry liquid appeared to affect substantially both the product distributions and the values of the model parameters relative to the corresponding gas-solid system.