System to Protect Catalyst in Liquid Phase Methanol (LPMEOH) Process from Trace Contaminants
Publication Date: 2003-Nov-25
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System to Protect Catalyst in Liquid Phase Methanol (LPMEOH™) Process from Trace Contaminants
The reactor used in the LPMEOH™ Process is unlike conventional gas phase methanol reactors that use fixed beds of catalyst pellets and largely depend upon recycle diluent gas to dilute the reactant concentration and thereby control the temperature rise caused by the heat of reaction. The LPMEOH™ reactor is a slurry reactor with small, powder-size catalyst particles (using the same precursor as the fixed-bed process) suspended in inert mineral oil. The syngas bubbles up through the slurry where hydrogen and carbon monoxide dissolve in the oil and diffuse to the catalyst surface where the methanol reaction occurs. The product methanol diffuses out of the slurry and exits as a vapor with the unreacted syngas. The inert oil acts as an efficient heat transfer medium and permits isothermal operation using an internal heat exchanger that produces steam.
The catalyst typically used for methanol synthesis (copper and zinc oxide on a support) can be irreversibly damaged by the presence of species that can be present in the synthesis gas supply. For example, sulfur (present in both coal and natural gas) is a known poison to methanol synthesis catalyst and must be removed to levels typically under 100 parts per billion by volume for economic catalyst life to be achieved. The technology to remove sulfur and other poisons to the part-per-million concentration is well established. An opportu...