Methanol Project Design a plant to make methanol from synthesis gas to supply a future market in direct methanol fuel cells

Methanol Project Don Robinson Documentation What we want to do => Basic Data Available Lab Facilities => Analysis & Planning Questionnaire to be worked on this week => Basic Data Methanol Project Don Robinson

Methanol Project Don Robinson Who We Are Limestone Engineering Consultants Ltd. Contracted by a major petroleum company Specific scenario (one of many): What does the client do if motor vehicle industry shifts to direct methanol fuel cells for environmental reasons Methanol Project Don Robinson

Methanol from Natural Gas Synthesis Gas: CH4 + H20 => CO + 3H2 Water Gas Shift: CO + H20 <=> CO2 + H2 Methanol from CO and CO2: CO + 2H2 <=> CH3OH CO2 + 3H2 <=> CH3OH + H2O Methanol Project Don Robinson

Methanol Project Don Robinson Our Task Our client has developed a design for a synthesis gas process We are to develop a design for a process to convert the synthesis gas to methanol The design is to be for a semi-commercial demo unit, although it is hoped that this will eventually lead to a world scale plant Methanol Project Don Robinson

Methanol Project Don Robinson Chemistry The earlier literature points out that methanol can be made from either CO or CO2 The latest thinking is that, with the commonly used catalytic systems, virtually all of the product comes from the CO2 reaction CO goes via a rapid water gas shift Methanol Project Don Robinson

Methanol Project Don Robinson A Problem Overall reaction is CH4 + H2O => CH3OH + H2 Conversion per pass is low (recycle required) To avoid H2 buildup it is necessary to separate it from a CO/CO2/CH4 mixture This is not easy to do Methanol Project Don Robinson

Methanol Project Don Robinson Our Solution Add sufficient CO2 to the synthesis gas so that there is a stoichiometric ratio That is, reaction to completion would result in zero amounts of CO, CO2, H2 Assume that CO2 is available from an ammonia plant or some similar source Methanol Project Don Robinson

Methanol Project Don Robinson Kinetics Both reactions are reversible - methane to syngas - syngas plus added CO2 to methanol We have determined experimentally values for rate and equilibrium constants Side reactions generate ethanol and fusel oil (no detailed kinetics) Methanol Project Don Robinson

Methanol Project Don Robinson Overall Process Recycle Product Reactor System Recycle System Separation Section Feeds Waste or Reuse Methanol Project Don Robinson

Methanol Project Don Robinson Previous Attempt A design for this process was developed last year Although technically successful, the economics did not look good We want to try again with a better reactor design Methanol Project Don Robinson

Removing Heat of Reaction Old design was 3 sets of: adiabatic packed bed reactor followed by heat exchanger New design is a single cooled reactor, much like a shell and tube heat exchanger, with catalyst in the tubes and coolant in the shell Methanol Project Don Robinson

Other Design Improvements Convert most CO to CO2 before the main reactor (less heat to remove) Do a better job of dealing with the impurities Get kinetic data in lab Reconfigure distillation train Utilize what was learned last year Methanol Project Don Robinson