Autothermal Reforming of Methane into Syngas and its Conversion into Methanol, Powered by Combustion of Excess Hydrogen or Excess Carbon Monoxide

Abstract

The proposed technical solution harnesses the Autothermal Methane Reforming (ATR) as an industrial process for “Blue” hydrogen (H2) production from natural gas, by converting of methane (CH4) into synthesis gas / syngas (CO + H2) using oxygen (O2) and either carbon dioxide (CO2) or steam (H2O) in an Exothermic Reaction with methane (CH4), the released heat of exothermic reaction satisfying heat requirements of the steam-reforming part of the ATR, so that the outlet 
temperature of the produced syngas is between 950–1100°C, while the outlet pressure is about 100 bar. Such high syngas pressures and temperatures employed in the ATR process are obtained by pressurization of atmospheric air and oxygen (contained in the air and extracted from it using an air separation unit) and the natural gas / methane (the main feedstock for the ATR reaction), by means of an air/oxygen compressor and a methane/ natural-gas compressor, respectively. High-pressure steam necessary for the ATR process is raised by harnessing of a huge (thermal and mechanical) energy potential of the waste heat contained in the stream of products (syngas). The proposed technical solution thus envisions conversion of a suitable amount of the waste heat contained in the produced syngas, so that the temperature of the syngas products reduces up to an optimum temperature for the process of Methanol Synthesis (~250°C) and also conversion of the heat of combustion of the excess hydrogen or excess carbon-monoxide (remaining after methanol synthesis of the syngas products) into the mechanical energy/
 power using a simple-reheat-cycle steam-turbine power plant, so that after satisfying/covering of the mechanical energy needed to drive the process compressors (for air, oxygen and methane), eventual surplus of mechanical energy remains that can be converted into an extra electrical energy. Thus, methanol is here produced without combustion of any additional external fuel (natural gas, fuel oil, coal or any other) and hence without any GHG emissions.