The water gas shift reaction (WGSR) is an important chemical process for enhancing the conversion of the syngas carbon monoxide contents into hydrogen by means of steam, in coal gasification power plants integrated with Carbon Capture and Storage (CCS) technologies. The carbon monoxide conversion and hydrogen generation may be based on multi-step reactors operating at decreasing temperatures, using highly efficient catalysts and integrated with membranes for hydrogen separation. This paper concerns an experimental investigation and numerical simulation on carbon monoxide conversion and hydrogen generation from water gas shift reaction using a small scale experimental apparatus based on a two-stage catalytic water-gas reactor. The main aim of the experimental apparatus is to support the design, optimization and operation of a pilot-scale plant for high sulphur (Sulcis) coal gasification, gas cleaning and treatment, CO2 separation, hydrogen and electricity production, recently installed at the Sotacarbo Research Centre. The laboratory test rig is based on two packed-bed reactors in series to be operated at different temperatures. It has been instrumented for temperature, flow rate and gas composition measurements, and can operate both in a two-stage or in a single-stage mode. The system has been designed for testing WGSR processes using different catalysts and at varying syngas temperatures (from 300 to 500 °C for the high temperature reactor and from 180 to 250 °C for the low temperature reactor) and initial syngas compositions (up to 100% of dry CO fraction). This paper investigates the characteristics of carbon monoxide conversion and hydrogen generation from the WGSR. The dry fuel gas mixture composition taken as the baseline composition for the laboratory test-rig, is similar to the expected fuel gas composition at the Sotacarbo gasifier outlet, produced by gasification of a mix of high sulphur (Sulcis-type) and low sulphur (South African-type) coal. This mixture is composed simply of H2, CO, CO2 and N2. The experimental investigation evaluates the performance of WGSR affected by various and important parameters, like catalyst type (Fe/Cr or Pt/Al for high temperature and Cu/Zn or Pt/Al for low temperature), residence time of reactants in the catalyst bed, reaction temperature and CO/steam ratio. The experimental results are supported by numerical analyses, based on equilibrium and kinetic models for the WGSR simulations.
Experimental investigation and numerical simulation of CO to CO2 conversion for hydrogen enrichment of syngas from an air-blown fixed bed up-draft coal gasifier
CAU, GIORGIO;
2009-01-01
Abstract
The water gas shift reaction (WGSR) is an important chemical process for enhancing the conversion of the syngas carbon monoxide contents into hydrogen by means of steam, in coal gasification power plants integrated with Carbon Capture and Storage (CCS) technologies. The carbon monoxide conversion and hydrogen generation may be based on multi-step reactors operating at decreasing temperatures, using highly efficient catalysts and integrated with membranes for hydrogen separation. This paper concerns an experimental investigation and numerical simulation on carbon monoxide conversion and hydrogen generation from water gas shift reaction using a small scale experimental apparatus based on a two-stage catalytic water-gas reactor. The main aim of the experimental apparatus is to support the design, optimization and operation of a pilot-scale plant for high sulphur (Sulcis) coal gasification, gas cleaning and treatment, CO2 separation, hydrogen and electricity production, recently installed at the Sotacarbo Research Centre. The laboratory test rig is based on two packed-bed reactors in series to be operated at different temperatures. It has been instrumented for temperature, flow rate and gas composition measurements, and can operate both in a two-stage or in a single-stage mode. The system has been designed for testing WGSR processes using different catalysts and at varying syngas temperatures (from 300 to 500 °C for the high temperature reactor and from 180 to 250 °C for the low temperature reactor) and initial syngas compositions (up to 100% of dry CO fraction). This paper investigates the characteristics of carbon monoxide conversion and hydrogen generation from the WGSR. The dry fuel gas mixture composition taken as the baseline composition for the laboratory test-rig, is similar to the expected fuel gas composition at the Sotacarbo gasifier outlet, produced by gasification of a mix of high sulphur (Sulcis-type) and low sulphur (South African-type) coal. This mixture is composed simply of H2, CO, CO2 and N2. The experimental investigation evaluates the performance of WGSR affected by various and important parameters, like catalyst type (Fe/Cr or Pt/Al for high temperature and Cu/Zn or Pt/Al for low temperature), residence time of reactants in the catalyst bed, reaction temperature and CO/steam ratio. The experimental results are supported by numerical analyses, based on equilibrium and kinetic models for the WGSR simulations.
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