Production of methanol

摘要

In the production of methanol from gaseous hydrocarbons having a lower C/H ratio than is stoichiometrically required to produce methanol and comprising the steps of catalytically cracking said hydrocarbons in the presence of water vapor at about 830 DEG to 930 DEG C. and about 5 to 30 bars to produce a synthesis gas consisting essentially of hydrogen and oxides of carbon, and subsequently catalytically converting said synthesis gas of hydrogen and oxides of carbon to methanol at about 230 DEG to 280 DEG C. and about 30 to 150 bars, the improvement which comprises transferring heat from the hot synthesis gas to the hydrocarbon-water vapor mixture flowing through the cracking catalyst thereby providing at least part of the heat required for the catalytic cracking of the hydrocarbons and reducing the consumption of thermal-/energy per unit of methanol produced. Advantageously, heat transfer is effected by passing the hot synthesis gas through a convoluted or corrugated tube embedded in the hydrocarbon cracking catalyst. Gaseous carbon-containing constituents of the methanol synthesis exhaust gas are removed by adsorption, and desorption; CO2 may later be removed from the residual methanol synthesis exhaust gas by methanol scrubbing and subsequent stripping, both the desorbed constituents and the CO2 being mixed with the hydrocarbons before they are cracked, whereby the C/H ratio of the hydrocarbon feed is raised and the consumption of the thermal-/energy per unit of methanol produced is reduced.