Gasification is a flexible technology which is applied in industry for electricity generation, hydrogen production, steam raising and liquid fuels production. Furthermore, it can utilize one or more feedstocks such as coal, biomass, municipal waste and petroleum coke. This versatility, in addition to being adaptable to various emissions control technologies (including carbon capture) renders it an attractive option for years to come. One of the most common gasifier types is the entrained-flow slagging gasifier. The behaviour of inorganic fuel components in these gasifiers is still ill-understood even though it can be the determining factor in their design and operation. A literature review of inorganic matter transformation sub-models for entrained-flow slagging gasifiers is provided. Slag viscosity was identified as a critical property in the sub-models. Slag viscosity models are only applicable to a limited range of slag compositions and conditions, and their performance is not easily assessed. An artificial neural network model was developed to predict slag viscosity over a broad range of temperatures and slag compositions. Furthermore, a toolbox was developed to assist slag viscosity model users in the selection of the best model for given slag compositions and conditions, and to help users determine how well the best model will perform. The slag viscosities of coal, petroleum coke and coal/petroleum coke blends were measured in the temperature range of 1175-1650ºC. Interaction of vanadium-rich slags with various materials was investigated. The results from the first two parts of a three-part research program which involves fuel characterization, testing in a 1 MWth gasifier, and computational fluid dynamics (CFD) modeling for entrained-flow slagging gasification are presented. The end goal is to develop a CFD model which includes inorganic matter transformations. Fuel properties were determined with prioritization based on their application; screening of potential fuels, ensuring proper gasifier operation, gasifier design and/or CFD modeling. Using CanmetENERGY’s 1 MWth gasifier, five gasification tests were completed with the characterized coals. Solid samples from the refractory liners, in-situ gas sampling probe sheaths and impingers, the slag tap, the slag pot, quench discharge water and scrubber water were collected and characterized.

Biofuels like ethanol are gaining serious momentum because of concerns over climate change and the rising cost of fossil fuels. Saskatchewan is the first province in Canada to pass a law requiring ethanol blended into its gasoline. A blend rate of 7.5% is mandated as of January 2007. This legislation is not yet fully enforced as ethanol production cannot currently meet demand, but local production is increasing. The traditional method of production is via grain fermentation; however the food versus fuel debate indicates this is unethical when food shortages and prices are already on the rise. Gasification is a robust technology for processing raw, non-food grade biomass into syngas (H2 and CO) which can then be further converted to ethanol via gas-to-liquid conversion technology. Condensable materials called tars form during gasification and must be further converted to gaseous products to avoid problems downstream. This can be achieved via optimization of process conditions and catalysis. The research for this thesis was carried out in two phases. Phase 1 examined the effects of process conditions on the noncatalytic temperature-programmed gasification of wood (Jack Pine) biomass. Temperature was varied from 700 to 825oC, water flow rate was varied from 2 to 5 cm3/h, and N2 flow rate from 16 to 32 cm3/min. When varying biomass gasification conditions, overall % carbon conversion to gaseous products reached a maximum of 70% at 825oC, 5.0 cm3/h H2O, and 32 cm3/min N2. 670 cm3 product gas per g biomass was produced, with 35.8 mol% H2 and H2:CO of 1.56. In Phase 2, catalytic gasification of wood biomass was carried out using a double bed micro reactor in a two-stage process. Temperature programmed steam gasification of biomass was performed in the first bed at 200-850oC. Following in the second bed was isothermal catalytic decomposition gasification of volatile compounds (including tars). Dolomites from Canada, Australia and Japan were examined for their effects on tar abatement and the overall gaseous product. The gasification of pine sawdust resulted in 74% of carbon emitted as volatile matter during tar gasification (200-500oC biomass bed temperature). High temperature, high H2O flow rate and low carrier gas flow rate are recommended for improving biomass conversion to gaseous products. Dolomites improved tar decomposition by an average 21% at 750oC isothermal catalyst bed temperature. For Canadian dolomites, iron content was found to promote tar conversion and the water-gas shift reaction, but the effectiveness reached a plateau at 1.0 wt% Fe present in dolomite. The best dolomite was Canada # 1, from an area west of Flin Flon, Manitoba. This dolomite yielded 66% tar conversion (25% above noncatalytic results) at 750oC using 1.6 cm3 catalyst/g biomass. Carbon conversion increased to 97% using 3.2 cm3 catalyst/g biomass at the same temperature. The dolomite seemed stable after 15 hours of cyclic use at 800oC.

Meat and bone meal (MBM) is a byproduct of the rendering industries. It is found to be responsible for the transmission of bovine spongiform encephalopathy (BSE) in animals and is no longer used as a feed to animals. There are various methods for disposal of MBM such as land filling, incineration, combustion, pyrolysis and gasification. Gasification appears to be one of the best options. High temperature of gasification reaction destroys the potential BSE pathogens and produces gases which can be further used to produce valuable liquid chemicals by Fischer-Tropsch synthesis or to generate electricity. Gasification of meat and bone meal followed by thermal cracking/ reforming of tar was carried out using oxygen and steam separately at atmospheric pressure using a two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking/ reforming of tar.<p> Meat and bone meal was successfully gasified in the two-stage fixed bed reaction system using two different oxidants (oxygen and steam) separately. In gasification using oxygen, the effects of temperature (650 850 °C) of both stages, equivalence ratio (ER) (actual O2 supply/stoichiometric O2 required for complete combustion) (0.15 0.3) and the second stage packed bed height (40 100 mm) on the product (char, tar and gas) yield and gas (H2, CO, CO2, CH4, C2H4, C2H6, C3H6, C3H8) composition were studied. It was observed that the two-stage process increased hydrogen production from 7.3 to 22.3 vol. % (N2 free basis) and gas yield from 30.8 to 54.6 wt. % compared to single stage. Temperature and equivalence ratio had significant effects on the hydrogen production and product distribution. It was observed that higher gasification (850 °C) and cracking (850°C) reaction temperatures were favorable for higher gas yield of 52.2 wt. % at packed bed height of 60 mm and equivalence ratio of 0.2. The tar yield decreased from 18.6 wt. % to 14.2 wt. % and that of gas increased from 50.6 wt. % to 54.6 wt. % by changing the packed bed height of second stage from 40 to 100 mm while the gross heating value (GHV) of the product gas remained almost constant (16.2 16.5 MJ/m3).<p> In gasification using steam, effects of temperature (650 850 °C) of each stage, steam/MBM (wt/ wt) (0.4 -0.8), and packed bed height (40 -100 mm) in second stage on the product (Char, liquid and gas) distribution and gas (H2, CO, CO2, CH4, C2H4, other H/C) composition were studied. It was observed that higher reaction temperature (850 °C) was favorable for high gas and hydrogen yields. Char gasification improved from 27 to 13 wt. % and hydrogen yield increased from 36.2 to 49.2 vol. % with increase in steam/MBM (wt/ wt), while with increased in packed bed height increased gas (29.5 to 31.6 wt. %) and hydrogen (45 to 49.2 vol. %) yields. It didnt show substantial effect on heavier hydrocarbons.<p> The kinetic parameters for the pyrolysis of meat and bone meal were determined using thermogravimetric analysis (TGA) at three different heating rates (10, 15 and 25 °C/min) using distributed activation energy model (DAEM). The activation energy was found in the range of 60-246 kJ/mol for the temperature range of 496-758 K and their corresponding frequency factors were 6.63 x 103 to 8.7 x 1014 s-1.

A pilot scale fluidized bed biomass gasifier developed at Texas A&M University in College Station, Texas was instrumented with thermocouples, pressure transducers and motor controllers for monitoring gasification temperature and pressure, air flow and biomass feeding rates. A process control program was also developed and employed for easier measurement and control. The gasifier was then evaluated in the gasification of sorghum, cotton gin trash (CGT) and manure and predicting the slagging and fouling tendencies of CGT and manure. The expected start-up time, operating temperature and desired fluidization were achieved without any trouble in the instrumented gasifier. The air flow rate was maintained at 1.99 kg/min and the fuel flow rate at 0.95 kg/min. The process control program considerably facilitated its operation which can now be remotely done. The gasification of sorghum, CGT and manure showed that they contained high amounts of volatile component matter and comparable yields of hydrogen, carbon monoxide and methane. Manure showed higher ash content while sorghum yielded lower amount of hydrogen. Their heating values and gas yields did not vary but were considered low ranging from only 4.09 to 4.19 MJ/m3 and from 1.8 to 2.5 m3/kg, respectively. The production of hydrogen and gas calorific values were significantly affected by biomass type but not by the operating temperature. The high values of the alkali index and base-to acid ratio indicated fouling and slagging tendencies of manure and CGT during gasification. The compressive strength profile of pelleted CGT and manure ash showed that the melting (or eutectic point) of these feedstock were around 800 degrees C for CGT and 600 degrees C for manure. Scanning electron microscopy (SEM) images showed relatively uniform bonding behavior and structure of the manure ash while CGT showed agglomeration in its structure as the temperature increased. The instrumentation of the fluidized bed gasifier and employing a process control program made its operation more convenient and safe. Further evaluation showed its application in quantifying the gasification products and predicting the slagging and fouling tendencies of selected biomass. With further development, a full automation of the operation of the gasifier may soon be realized.

Biomass gasification is considered a key technology in reaching targets for renewable energy and CO2 emissions reduction. This thesis studies the feasibility of a new technology of biomass gasification called WoodRoll for the production of Syngas with the aim to replace fossil fuels in the furnaces of the steel company OVAKO in Hofors.  This research attempts to study the techno-economic viability of WoodRoll technology integration with the district heating company HEAB, creating a synergy between the companies and WoodRoll technology. Moreover, a theoretically study of the environmental impact, concerning greenhouse effect and pollutants it is also carried out.   In the future scenario HEAB, as an energy supplier will be the gasification plant owner supplying with Syngas 5% cheaper than the fuels that they use today to Ovako.  Three different scenarios have been studied varying the capacity of the gasification plant. The scenarios are 5MW, 10MW and 15MW capacity.   The study show that the system is technically viable being possible to create a synergy  between the three process improving efficiency and decreasing cost and CO2 emissions.   The results from the economic study show that biomass gasification using WoodRoll technology is a highly interesting investment option for HEAB. From Ovako side, the project is very interesting too since the company can have a combustible 5% cheaper than the fuels used today without doing any investment. In 5MW scenario, 40GWh per year are converted in Ovako from oil to Syngas. With an investment for HEAB of 9.8 mSEK, profits were a Net Present Value of 6.3mSEK with 7.8 years of payback period. In 10MW scenario 80GWh were replaced. In this scenario, required investment was 146 mSEK with a NPV of 32.5 mSEK . Payback in this case was 6.3 years. The most profitable scenario was the case of 15M. With an investment of 188 mSEK the profits of the project were 60mSEK with a payback period of 5.8 years. In the three cases, especially in 15MW case, sensitivity study of the system show that it is very robust to changes in biomass cost and Syngas price. This parameters have a big impact on the profits but a big margin until becomes unfeasible.   From Ovako side, savings for the fuel conversion were 1.2; 2.4 and 3.6mSEK for the 5, 10 and 15MW respectively. Reduction of CO2 emissions was 11, 20 and 30 thousands of CO2 tons for the three scenarios allowing  the company to sell CO2 allowances and having an extra profit of 3, 6 and 8mSEK per year in the 5, 10 and 15MW scenario respectively.

Biofuels like ethanol are gaining serious momentum because of concerns over climate change and the rising cost of fossil fuels. Saskatchewan is the first province in Canada to pass a law requiring ethanol blended into its gasoline. A blend rate of 7.5% is mandated as of January 2007. This legislation is not yet fully enforced as ethanol production cannot currently meet demand, but local production is increasing. The traditional method of production is via grain fermentation; however the food versus fuel debate indicates this is unethical when food shortages and prices are already on the rise. Gasification is a robust technology for processing raw, non-food grade biomass into syngas (H2 and CO) which can then be further converted to ethanol via gas-to-liquid conversion technology. Condensable materials called tars form during gasification and must be further converted to gaseous products to avoid problems downstream. This can be achieved via optimization of process conditions and catalysis. The research for this thesis was carried out in two phases. Phase 1 examined the effects of process conditions on the noncatalytic temperature-programmed gasification of wood (Jack Pine) biomass. Temperature was varied from 700 to 825oC, water flow rate was varied from 2 to 5 cm3/h, and N2 flow rate from 16 to 32 cm3/min. When varying biomass gasification conditions, overall % carbon conversion to gaseous products reached a maximum of 70% at 825oC, 5.0 cm3/h H2O, and 32 cm3/min N2. 670 cm3 product gas per g biomass was produced, with 35.8 mol% H2 and H2:CO of 1.56. In Phase 2, catalytic gasification of wood biomass was carried out using a double bed micro reactor in a two-stage process. Temperature programmed steam gasification of biomass was performed in the first bed at 200-850oC. Following in the second bed was isothermal catalytic decomposition gasification of volatile compounds (including tars). Dolomites from Canada, Australia and Japan were examined for their effects on tar abatement and the overall gaseous product. The gasification of pine sawdust resulted in 74% of carbon emitted as volatile matter during tar gasification (200-500oC biomass bed temperature). High temperature, high H2O flow rate and low carrier gas flow rate are recommended for improving biomass conversion to gaseous products. Dolomites improved tar decomposition by an average 21% at 750oC isothermal catalyst bed temperature. For Canadian dolomites, iron content was found to promote tar conversion and the water-gas shift reaction, but the effectiveness reached a plateau at 1.0 wt% Fe present in dolomite. The best dolomite was Canada # 1, from an area west of Flin Flon, Manitoba. This dolomite yielded 66% tar conversion (25% above noncatalytic results) at 750oC using 1.6 cm3 catalyst/g biomass. Carbon conversion increased to 97% using 3.2 cm3 catalyst/g biomass at the same temperature. The dolomite seemed stable after 15 hours of cyclic use at 800oC.

Meat and bone meal (MBM) is a byproduct of the rendering industries. It is found to be responsible for the transmission of bovine spongiform encephalopathy (BSE) in animals and is no longer used as a feed to animals. There are various methods for disposal of MBM such as land filling, incineration, combustion, pyrolysis and gasification. Gasification appears to be one of the best options. High temperature of gasification reaction destroys the potential BSE pathogens and produces gases which can be further used to produce valuable liquid chemicals by Fischer-Tropsch synthesis or to generate electricity. Gasification of meat and bone meal followed by thermal cracking/ reforming of tar was carried out using oxygen and steam separately at atmospheric pressure using a two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking/ reforming of tar.<p> Meat and bone meal was successfully gasified in the two-stage fixed bed reaction system using two different oxidants (oxygen and steam) separately. In gasification using oxygen, the effects of temperature (650 850 °C) of both stages, equivalence ratio (ER) (actual O2 supply/stoichiometric O2 required for complete combustion) (0.15 0.3) and the second stage packed bed height (40 100 mm) on the product (char, tar and gas) yield and gas (H2, CO, CO2, CH4, C2H4, C2H6, C3H6, C3H8) composition were studied. It was observed that the two-stage process increased hydrogen production from 7.3 to 22.3 vol. % (N2 free basis) and gas yield from 30.8 to 54.6 wt. % compared to single stage. Temperature and equivalence ratio had significant effects on the hydrogen production and product distribution. It was observed that higher gasification (850 °C) and cracking (850°C) reaction temperatures were favorable for higher gas yield of 52.2 wt. % at packed bed height of 60 mm and equivalence ratio of 0.2. The tar yield decreased from 18.6 wt. % to 14.2 wt. % and that of gas increased from 50.6 wt. % to 54.6 wt. % by changing the packed bed height of second stage from 40 to 100 mm while the gross heating value (GHV) of the product gas remained almost constant (16.2 16.5 MJ/m3).<p> In gasification using steam, effects of temperature (650 850 °C) of each stage, steam/MBM (wt/ wt) (0.4 -0.8), and packed bed height (40 -100 mm) in second stage on the product (Char, liquid and gas) distribution and gas (H2, CO, CO2, CH4, C2H4, other H/C) composition were studied. It was observed that higher reaction temperature (850 °C) was favorable for high gas and hydrogen yields. Char gasification improved from 27 to 13 wt. % and hydrogen yield increased from 36.2 to 49.2 vol. % with increase in steam/MBM (wt/ wt), while with increased in packed bed height increased gas (29.5 to 31.6 wt. %) and hydrogen (45 to 49.2 vol. %) yields. It didnt show substantial effect on heavier hydrocarbons.<p> The kinetic parameters for the pyrolysis of meat and bone meal were determined using thermogravimetric analysis (TGA) at three different heating rates (10, 15 and 25 °C/min) using distributed activation energy model (DAEM). The activation energy was found in the range of 60-246 kJ/mol for the temperature range of 496-758 K and their corresponding frequency factors were 6.63 x 103 to 8.7 x 1014 s-1.

Petroleum coke or petcoke, a refinery byproduct, has generally been considered as an unusable byproduct because of its high sulfur content. However energy industries now view petcoke as a potential feedstock for power generation because it has higher carbon content than other hydrocarbons like coal, biomass and sewage residue. This gives petcoke a great edge over other feedstocks to generate power. Models for the two most common processes for power generation, namely combustion and gasification, were developed using Aspen Plus steady state chemical process simulator. Overall plant layouts for both processes were developed by calculating the heat and mass balance of the unit operations. After conducting wide sensitivity analysis, results indicate that one ton of petcoke feedstock can generate up to 4 MW of net available power. Both processes have rates of return greater than 30%, although gasification offers a slightly more attractive opportunity than combustion.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed October 13, 2009). PDF text: xiv, 183 p. : ill. (some col.) ; 1 Mb. UMI publication number: AAT 3358961. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xi, 106 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 96-98).