Numerical study with ChemKin for hydrogasification mechanism of pulverized coal and Hg speciation transformation inside a hydrogasifier

Received (Primljeno): 2012-02-22 Accepted (Prihvaćeno): 2012-05-28 Original scientific paper Zero-emission coal (ZEC) technology has been actively studied recently. It aims to achieve zero emission of CO2 and other pollutants and the efficiency of this system can reach no less than 70%. Hydro-gasification of pulverized coal is a core process of ZEC. However, the mechanism of gasification and transformation of mercury speciation in the hydrogasification is has not been understood precisely up until now. This restrains the ZEC’s commercialization. The purpose of this paper is to study the mechanism of hydro-gasification and mercury speciation transformation for coal in the gasifier with high temperature and pressure. Detailed chemical kinetics mechanism (CKM) has been proposed for hydro-gasification for pulverized coal in an entrained flow hydro-gasifier. The effects have been studied for different reaction conditions on hydrogasification products and evolution of Hg in terms of the chemical reaction kinetics method. The CKM mechanism includes 130 elementary reactions and is solved with commercially available software, ChemKin. The calculation results are validated against the experimental data from literature and meaningful predictions are finally obtained. In addition, the chemical equilibrium calculation (CEC) is also used for predictions. Although the CEC method assumes all the reactions have reached chemical equilibrium, which is not the case in industrial reality, the calculation results are of value as reference.

[1]  Ashok Rao,et al.  Performance and costs of advanced sustainable central power plants with CCS and H2 co-production , 2012 .

[2]  Emmanuel Kakaras,et al.  Design and optimization of carbon-free power generation based on coal hydrogasification integrated with SOFC , 2009 .

[3]  Giovanni Lozza,et al.  Zecomix: A zero-emissions coal power plant, based on hydro-gasification, CO2 capture by calcium looping and semi-closed high temperature steam cycle , 2009 .

[4]  W. Lili,et al.  Chemical kinetics-based analysis for utilities of ZEC power generation system , 2008 .

[5]  Paolo Fiorini,et al.  Possible optimal configurations for the ZECOMIX high efficiency zero emission hydrogen and power plant , 2008 .

[6]  George W. Roberts,et al.  Chemical reactions and chemical reactors , 2008 .

[7]  W. Guo-qiang.  The chemistry energetics model forecast of coal gasified after hydrogenated , 2007 .

[8]  Andrés Melgar,et al.  Thermochemical equilibrium modelling of a gasifying process. , 2007 .

[9]  Jae Goo Lee,et al.  Hydrogasification characteristics of bituminous coals in an entrained-flow hydrogasifier , 2006 .

[10]  Sun Xing-fu.  STUDY ON THE PARAMETERS THAT INFLUENCE THE EFFICIENCY OF DE-NO IN ADVANCED NATURAL GAS REBURNINGAREA BY EXPERIMENTALAND KINETIC MODEL , 2005 .

[11]  Cen Ke-fa.  Modelling on effects of operation parameters on entrained flow coal gasification (I): Model establishment and validation , 2004 .

[12]  Brian S. Haynes,et al.  Chemical kinetic modeling of the H/S system: H2S thermolysis and H2 sulfidation , 2002 .

[13]  John Lucas,et al.  The effects of pressure on coal reactions during pulverised coal combustion and gasification , 2002 .

[14]  S. Niksa,et al.  Kinetic modeling of homogeneous mercury oxidation: the importance of NO and H2O in predicting oxidation in coal-derived systems. , 2001, Environmental science & technology.

[15]  K. N. Seetharamu,et al.  Prediction of performance of a downdraft gasifier using equilibrium modeling for different biomass materials , 2001 .

[16]  K. Lackner,et al.  ZERO EMISSION COAL POWER, A NEW CONCEPT , 2001 .

[17]  K. Lackner,et al.  Zero emission coal , 2000 .

[18]  D. N. Nilsen,et al.  Carbon dioxide sequestration by direct mineral carbonation with carbonic acid , 2000 .

[19]  P. Marshall,et al.  Experimental and ab Initio Investigations of the Kinetics of the Reaction of H Atoms with H 2 S , 1999 .

[20]  H. Matsui,et al.  INVESTIGATION ON THE INSERTION CHANNEL IN THE S(3P) + H2 REACTION , 1998 .

[21]  Robert W. Dibble,et al.  Combustion: Physical and Chemical Fundamentals, Modelling and Simulation, Experiments, Pollutant Formation , 1996 .

[22]  J. Troe,et al.  UV Absorption Study of the Thermal Decomposition Reaction H2S .fwdarw. H2 + S(3P) , 1994 .

[23]  A. P. Watkinson,et al.  A PREDICTION OF PERFORMANCE OF COMMERCIAL COAL GASIFIERS , 1991 .

[24]  P. A. Tesner,et al.  Kinetics of the thermal decomposition of hydrogen sulfide at 600-1200°C , 1990 .