ABSTRACT Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol... more ABSTRACT Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol or gasoline (MTG) are examined using a self-consistent design, simulation and cost analysis framework. Three basic production routes are considered: (1) production from biomass via gasification; (2) from carbon dioxide and electricity via water electrolysis; (3) from biomass and electricity via hybrid process combining elements from routes (1) and (2). Process designs are developed based on technologies that are either commercially available or successfully demonstrated at precommercial scale. The prospective economics of future facilities coproducing fuels and district heat are evaluated from the perspective of a synthetic fuel producer. The levelised production costs range from 18–37 €/GJ for natural gas, 21–40 €/GJ for methanol and 23–48 €/GJ for gasoline, depending on the production route. For a given end-product, the lowest costs are associated with thermochemical plant configurations, followed by hybrid and electrochemical plants.
ABSTRACT A thermochemical processing route from biomass residues to light olefins (ethylene and p... more ABSTRACT A thermochemical processing route from biomass residues to light olefins (ethylene and propylene) is assessed by means of process simulation and cost analysis. A two-step process chain is proposed where (1) biomass residues are first converted to synthetic methanol in a gasification plant situated close to feedstock resources and (2) the produced methanol is transported to a steam cracking site where it is further converted in a methanol to olefins (MTO) plant. Possibilities for heat and product integration as well as equipment sharing with a steam cracking plant are discussed. Overall mass yields from dry biomass to light olefins range from 169 to 203 kg/t. Based on cursory capital cost estimates, the maximum methanol purchase price for such integrated MTO plants is estimated to be in the range of 420–450 €/t.
ABSTRACT Reforming is a key enabling technology for the production of tar and hydrocarbon free sy... more ABSTRACT Reforming is a key enabling technology for the production of tar and hydrocarbon free synthesis gas from biomass. In this work, two different reforming concepts, steam and autothermal reforming, were studied for cleaning of biomass-derived gasification gas. Long-term laboratory scale experiments (around 500 h) were carried out with two model biomass gasification gas compositions with low and medium hydrocarbon loads. The experiments were made using nickel and precious metal catalysts at atmospheric pressure and at temperatures around 900–950 °C. The deactivation of the catalysts was followed. Gas with low hydrocarbon content could be steam reformed with nickel and precious metal catalyst. Both autothermal and steam reforming modes were studied for gas with medium hydrocarbon content. In steam reforming mode, the catalysts deactivated more than in autothermal mode. Based on the experiments H2O/CREF molar ratio above 4 and O/CREF molar ratio above 8 are recommended. A concept assessment was carried out to examine plant level impacts of the reforming approaches to synthesis gas production. The results showed that the choice of reforming concept has only limited impact to the overall efficiency of synthetic biofuel production.
ABSTRACT The biomass gasification process is modelled by utilising constrained thermodynamic equi... more ABSTRACT The biomass gasification process is modelled by utilising constrained thermodynamic equilibrium. The formation of char, tar, ammonia and light hydrocarbons and related syngas composition were described by extending the conventional chemical system with additional immaterial constraints and by defining process-dependent values for these constraints. Six different model structures were evaluated from global thermodynamic equilibrium to fully constrained local equilibrium. When models were validated against gasification setups, it was not necessary to fully constrain the system, as sufficient results were obtained by implementing constraints for char, tar, ammonia, CH4 formation as well as for the amount of carbon in light hydrocarbons. The method was shown to be versatile when it was validated against other gasification setups: by altering the models defining the constraints a new gasification conditions could be simulated. A clear benefit of the proposed method is that the gasification process can be resolved as a restricted partial equilibrium with a single calculation step. Another benefit is that chemical reactions, gasification enthalpy and the states of the system are estimated concurrently.
ABSTRACT Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol... more ABSTRACT Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol or gasoline (MTG) are examined using a self-consistent design, simulation and cost analysis framework. Three basic production routes are considered: (1) production from biomass via gasification; (2) from carbon dioxide and electricity via water electrolysis; (3) from biomass and electricity via hybrid process combining elements from routes (1) and (2). Process designs are developed based on technologies that are either commercially available or successfully demonstrated at precommercial scale. The prospective economics of future facilities coproducing fuels and district heat are evaluated from the perspective of a synthetic fuel producer. The levelised production costs range from 18–37 €/GJ for natural gas, 21–40 €/GJ for methanol and 23–48 €/GJ for gasoline, depending on the production route. For a given end-product, the lowest costs are associated with thermochemical plant configurations, followed by hybrid and electrochemical plants.
ABSTRACT A thermochemical processing route from biomass residues to light olefins (ethylene and p... more ABSTRACT A thermochemical processing route from biomass residues to light olefins (ethylene and propylene) is assessed by means of process simulation and cost analysis. A two-step process chain is proposed where (1) biomass residues are first converted to synthetic methanol in a gasification plant situated close to feedstock resources and (2) the produced methanol is transported to a steam cracking site where it is further converted in a methanol to olefins (MTO) plant. Possibilities for heat and product integration as well as equipment sharing with a steam cracking plant are discussed. Overall mass yields from dry biomass to light olefins range from 169 to 203 kg/t. Based on cursory capital cost estimates, the maximum methanol purchase price for such integrated MTO plants is estimated to be in the range of 420–450 €/t.
ABSTRACT Reforming is a key enabling technology for the production of tar and hydrocarbon free sy... more ABSTRACT Reforming is a key enabling technology for the production of tar and hydrocarbon free synthesis gas from biomass. In this work, two different reforming concepts, steam and autothermal reforming, were studied for cleaning of biomass-derived gasification gas. Long-term laboratory scale experiments (around 500 h) were carried out with two model biomass gasification gas compositions with low and medium hydrocarbon loads. The experiments were made using nickel and precious metal catalysts at atmospheric pressure and at temperatures around 900–950 °C. The deactivation of the catalysts was followed. Gas with low hydrocarbon content could be steam reformed with nickel and precious metal catalyst. Both autothermal and steam reforming modes were studied for gas with medium hydrocarbon content. In steam reforming mode, the catalysts deactivated more than in autothermal mode. Based on the experiments H2O/CREF molar ratio above 4 and O/CREF molar ratio above 8 are recommended. A concept assessment was carried out to examine plant level impacts of the reforming approaches to synthesis gas production. The results showed that the choice of reforming concept has only limited impact to the overall efficiency of synthetic biofuel production.
ABSTRACT The biomass gasification process is modelled by utilising constrained thermodynamic equi... more ABSTRACT The biomass gasification process is modelled by utilising constrained thermodynamic equilibrium. The formation of char, tar, ammonia and light hydrocarbons and related syngas composition were described by extending the conventional chemical system with additional immaterial constraints and by defining process-dependent values for these constraints. Six different model structures were evaluated from global thermodynamic equilibrium to fully constrained local equilibrium. When models were validated against gasification setups, it was not necessary to fully constrain the system, as sufficient results were obtained by implementing constraints for char, tar, ammonia, CH4 formation as well as for the amount of carbon in light hydrocarbons. The method was shown to be versatile when it was validated against other gasification setups: by altering the models defining the constraints a new gasification conditions could be simulated. A clear benefit of the proposed method is that the gasification process can be resolved as a restricted partial equilibrium with a single calculation step. Another benefit is that chemical reactions, gasification enthalpy and the states of the system are estimated concurrently.
Uploads
Papers by ILKKA HANNULA