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02976 Research on biomass fast pyrolysis for liquid fuel
09 Combustion (bumers, combustion systems) OH and CO, near the catalyst bed exit. The parametric study for various operating conditions, such as equivalence ratio, temperature, velocity, entrance diameter of the monolith channel and inlet pressure, were also performed to investigate their effects on catalytic combustion. In the thermal combustor, N20 was a dominant component in emissions that are mainly formed under the reaction mechanism, N2+O(+M)-+NzO(+M), in case no additional fuel is injected. Furthermore, the formations of CO and NOx emission were also characterized with controlling the amount of additional methane injection to the thermal combustor.
04/02973 On the technical and economic issues involved in the co-firing of coal and waste in a conventional pf-fired power station Ireland, S. N. et al. Fuel, 2004, 83, (7 8), 905 915. The introduction of co-firing schemes to large-scale utility plant has to date been limited in the UK. The need to conform to ever more stringent emissions legislation, reduced levels of carbon dioxide (CO2), and the recently introduced Renewables Obligations Certificates (ROCs) means that conventional power stations are having to change their operating philosophy and encompass new technologies and operating techniques. The current paper describes some of the key work associated with the feasibility, design, and construction stages of a 100 000 tonne/annum dried sewage sludge co-firing facility attached to an existing 2400 MWe pf-fired power station. The scheme is one of the first of its type and the largest in the UK, and represents an important milestone in the complex progress of integrating a biomass fuel with a conventional boiler process. Critical steps in the initial feasibility phase of the design process are described, such as the detailed evaluation of the raw materials suitability for co-firing in terms of the chemical and physical properties of the waste fuel. The resultant raw material properties are presented as input data to a detailed computer model developed by Sinclair Knight Merz (Europe) Ltd, the output of which indicates the co-firing potential of the composite fuel with respect to its impact on plant efficiency, thermal balance, flue gas characteristics, system performance (throughput, materials and maintenance) and potential for environmental impact. Specific areas of interest are highlighted such as fuel volatility, emission levels, trace element partitioning, ash composition and behaviour, fouling and slagging mechanisms and predicted erosion and corrosion levels. Consenting requirements of the co-firing schemes have also been considered, with the Integrated Pollution Control (IPC), Integrated Pollution Prevention and Control (IPPC), Town and Country Planning and the Electricity Act (Section 36 Consent) being examined.
04/02974 Pyrolysis as a technique for separating heavy metals from hyperaccumulators. Part II1: pilot-scale pyrolysis of synthetic hyperaccumulator biomass Koppotu, L. et al. Biomass and Bioenergy, 2004, 26, (5), 463-472. Synthetic hyper-accumulator biomass (SHB) feed impregnated with Ni, Zn or Cu was used to conduct six experiments in a pilot-scale, spouted bed gasifier. Two runs each using corn stover with no metal added (blank runs) were also conducted. The reactor was operated in an entrained mode in an oxygen free (N2) environment at 873 K and 1 atm. The apparent gas residence time in the heated zone of the pilotscale reactor was 1.4 s at 873 K. The material balance closure for the eight experiments on an N2-free basis varied between 79% and 92%. Nearly 99% of the metal recovered in the product stream was concentrated in the char formed by pyrolysing the SHB in the reactor. The metal concentration in the char varied between 6.6% and 16.6%, depending on the type of metal and whether the char was collected in the cyclone or ashbox. The metal component was concentrated by 3.2-6 times in the char, compared to the feed.
04/02975 Pyrolytic characteristics of blended coal and woody biomass Moghtaderi, B. et al. Fuel, 2004, 83, (6), 745-750. Pyrolytic characteristics of biomass/coal mixtures were investigated under conditions pertinent to pulverized fuel boilers. It was found that the mixtures of biomass/coal follow the behaviour of their parent materials in an additive manner. The two fuels did not chemically interact under inert conditions indicating a general lack of synergistic effects. As such, the yield of the major pyrolysis products is linearly proportional to the percentage of biomass and coal in the mixture. Even the compositions of the gaseous products from blended samples are linearly proportional to those of their parent fuels. These findings can potentially help to understand and predict the behaviour of biomass/coal blends in practical systems.
04/02976
Research on biomass fast pyrolysis for liquid fuel
Luo, Z. et al. Biomass and Bioenergy, 2004, 26, (5), 455 462. A fluidized bed reactor with 3 kg h 1 throughput operating at an atmospheric pressure with an inert atmosphere at 773 K has been used to produce bio-oils from the wood feedstocks such as Pteroearpus indieus, Cunninghamia laneeolata, and Fraxinus mandshuriea, as well as
420
Fuel and Energy Abstracts
November 2004
from rice straw. The best oil-producing characteristics were for P. indieus and the worst were with rice straw. These data were used to design a larger scale unit of 20 kg h 1 throughput, and to estimate the production costs at an industrial scale. The quality of the bio-oil produced remains poor, and a combination of high-value products and energy applications are needed for profitability.
04102977 Slow pyrolysis of different PVC types in a bubbling fluidized bed: stabilizer effects Saeed, L. et al. Journal ~?f Analytical and Applied Pyrolysis, 2004, 72, (1), 63-74. The effect of stabilizers on thermal degradation of poly(viny| chloride) (PVC) in a bubbling fluidized bed (BFB) was studied as part of a process assessment for high-PVC waste treatment. The BFB reactor operated at temperatures between 200 and 400°C and three types of PVC were used in the tests: a pure rigid bottle-grade containing some tin compounds stabilizer, an old, light grey sewage PVC pipe with lead compound stabilizer and a newer orange sewage PVC pipe with Ca/Zn compounds stabilizer. The pyrolysis gases from the BFB were analysed with a Fourier transform infrared (FT-IR) spectrometer. The result from the tests and char analysis showed that the weight fraction and the type of stabilizer, especially lead compound, have a major effect by slowing PVC degradation especially at the first degradation stage compared to a purer PVC which contains only a small amount of tin based stabilizer. The results also showed that a temperature range 340350°C, where most of the chlorine for all types used in the tests was released, is optimal for operating the BFB pyrolysis reactor.
04/02978 The effects of particle characteristics on emissions from burning wood fuel powder Paulrud, S. and Nilsson, C. Fuel, 2004, 83, (7-8), 813-821. Wood fuel powders cut in different mills were combusted in a 150 kW burner to study emissions, furnace temperature and burnout as a function of particle size distribution and particle shape. Particle characteristics only slightly influenced NOx formation but more strongly influenced fuel feeding, ignition, unburned pollutants and furnace temperature. The lowest NOx emissions achieved was < 50 rag/ MJ. For finely milled wood powder, CO emissions had the lowest values (2I mg/MJ). Varying the ratio between primary, secondary and tertiary airflows, slightly influenced the combustion results using a small-scale powder burner.
04/02979 Thermally-stable refractory shotcrete material for repairing coke-oven wall linings Berkutov, N. A. et al. Russ. RU 2,203,249 (CI. C04B35/65), 27 Apr 2003, Appl. 2,001,118,909. (In Russian) The invention is suitable in the manufacture of refractory materials intended for hot repair of coke-ovens. The shotcrete refractory material contains quartzite 82-86, silicon 12-16, aluminium 1.2-1.7, and feldspar 0.5-1 weight %. This mixture is deposited onto the lining with the flow of oxygen, natural gas, or their mixture. The resulting composition provides enhanced repair efficiency, and exhibits temperature stability up to 1500 °. Compressive strength of the material is 23-26 MPa.
04/02980 Transformation of mineral and emission of particulate matters during co-combustion of coal with sewage sludge Ninomiya, Y. et al. Fuel, 2004, 83, (6), 751-764. Co-combustion of coal with sewage sludge was carried out in laboratory-scaled drop tube furnace to understand the interaction between different fuels. The combustion conditions were selected as follows: the raw material feeding rate was 0.2-0.3 g/rain, temperature was 1200°C, the atmosphere of 10% 02 and N2 being balance was used to guarantee an air ratio of 1.5, and the residence time varied from 0.6 to 2.4 s. The coal/sewage sludge is kept at 50:50 (wt% to wt%), four fuel pairs were selected with respect to the mineral association within individual fuel. The results showed the obvious interaction between coal and sewage sludge during their co-combustion. For the carbon conversion, the devolatilization of mixing fuel occurred quickly; the combustion of both char and evolved volatile progressed almost completely. As a result, the un-burnt carbon was almost zero in the fly ash. In addition, the evolution of both mineral and PM varied with the association of minerals in raw fuels. For both coal and sewage sludge rich in included minerals, they combusted separately in the furnace, less interaction occurred accordingly. Conversely, for both them rich in excluded minerals, the minerals reacted with each other to form much agglomeration, and therefore, the particle size of the fly ash was increased, while the amount of PM was decreased, which changed as the coarse fly ash particles. Finally, for the case of coal rich in excluded mineral and sludge rich in included mineral, their cocombustion led to the interaction of their minerals. As a result, more the fine particles were formed, which in part changed into PM. For the vaporized trace elements, they were adsorbed by the melt CaPO4/AI-Si
04/02973 On the technical and economic issues involved in the co-firing of coal and waste in a conventional pf-fired power station Ireland, S. N. et al. Fuel, 2004, 83, (7 8), 905 915. The introduction of co-firing schemes to large-scale utility plant has to date been limited in the UK. The need to conform to ever more stringent emissions legislation, reduced levels of carbon dioxide (CO2), and the recently introduced Renewables Obligations Certificates (ROCs) means that conventional power stations are having to change their operating philosophy and encompass new technologies and operating techniques. The current paper describes some of the key work associated with the feasibility, design, and construction stages of a 100 000 tonne/annum dried sewage sludge co-firing facility attached to an existing 2400 MWe pf-fired power station. The scheme is one of the first of its type and the largest in the UK, and represents an important milestone in the complex progress of integrating a biomass fuel with a conventional boiler process. Critical steps in the initial feasibility phase of the design process are described, such as the detailed evaluation of the raw materials suitability for co-firing in terms of the chemical and physical properties of the waste fuel. The resultant raw material properties are presented as input data to a detailed computer model developed by Sinclair Knight Merz (Europe) Ltd, the output of which indicates the co-firing potential of the composite fuel with respect to its impact on plant efficiency, thermal balance, flue gas characteristics, system performance (throughput, materials and maintenance) and potential for environmental impact. Specific areas of interest are highlighted such as fuel volatility, emission levels, trace element partitioning, ash composition and behaviour, fouling and slagging mechanisms and predicted erosion and corrosion levels. Consenting requirements of the co-firing schemes have also been considered, with the Integrated Pollution Control (IPC), Integrated Pollution Prevention and Control (IPPC), Town and Country Planning and the Electricity Act (Section 36 Consent) being examined.
04/02974 Pyrolysis as a technique for separating heavy metals from hyperaccumulators. Part II1: pilot-scale pyrolysis of synthetic hyperaccumulator biomass Koppotu, L. et al. Biomass and Bioenergy, 2004, 26, (5), 463-472. Synthetic hyper-accumulator biomass (SHB) feed impregnated with Ni, Zn or Cu was used to conduct six experiments in a pilot-scale, spouted bed gasifier. Two runs each using corn stover with no metal added (blank runs) were also conducted. The reactor was operated in an entrained mode in an oxygen free (N2) environment at 873 K and 1 atm. The apparent gas residence time in the heated zone of the pilotscale reactor was 1.4 s at 873 K. The material balance closure for the eight experiments on an N2-free basis varied between 79% and 92%. Nearly 99% of the metal recovered in the product stream was concentrated in the char formed by pyrolysing the SHB in the reactor. The metal concentration in the char varied between 6.6% and 16.6%, depending on the type of metal and whether the char was collected in the cyclone or ashbox. The metal component was concentrated by 3.2-6 times in the char, compared to the feed.
04/02975 Pyrolytic characteristics of blended coal and woody biomass Moghtaderi, B. et al. Fuel, 2004, 83, (6), 745-750. Pyrolytic characteristics of biomass/coal mixtures were investigated under conditions pertinent to pulverized fuel boilers. It was found that the mixtures of biomass/coal follow the behaviour of their parent materials in an additive manner. The two fuels did not chemically interact under inert conditions indicating a general lack of synergistic effects. As such, the yield of the major pyrolysis products is linearly proportional to the percentage of biomass and coal in the mixture. Even the compositions of the gaseous products from blended samples are linearly proportional to those of their parent fuels. These findings can potentially help to understand and predict the behaviour of biomass/coal blends in practical systems.
04/02976
Research on biomass fast pyrolysis for liquid fuel
Luo, Z. et al. Biomass and Bioenergy, 2004, 26, (5), 455 462. A fluidized bed reactor with 3 kg h 1 throughput operating at an atmospheric pressure with an inert atmosphere at 773 K has been used to produce bio-oils from the wood feedstocks such as Pteroearpus indieus, Cunninghamia laneeolata, and Fraxinus mandshuriea, as well as
420
Fuel and Energy Abstracts
November 2004
from rice straw. The best oil-producing characteristics were for P. indieus and the worst were with rice straw. These data were used to design a larger scale unit of 20 kg h 1 throughput, and to estimate the production costs at an industrial scale. The quality of the bio-oil produced remains poor, and a combination of high-value products and energy applications are needed for profitability.
04102977 Slow pyrolysis of different PVC types in a bubbling fluidized bed: stabilizer effects Saeed, L. et al. Journal ~?f Analytical and Applied Pyrolysis, 2004, 72, (1), 63-74. The effect of stabilizers on thermal degradation of poly(viny| chloride) (PVC) in a bubbling fluidized bed (BFB) was studied as part of a process assessment for high-PVC waste treatment. The BFB reactor operated at temperatures between 200 and 400°C and three types of PVC were used in the tests: a pure rigid bottle-grade containing some tin compounds stabilizer, an old, light grey sewage PVC pipe with lead compound stabilizer and a newer orange sewage PVC pipe with Ca/Zn compounds stabilizer. The pyrolysis gases from the BFB were analysed with a Fourier transform infrared (FT-IR) spectrometer. The result from the tests and char analysis showed that the weight fraction and the type of stabilizer, especially lead compound, have a major effect by slowing PVC degradation especially at the first degradation stage compared to a purer PVC which contains only a small amount of tin based stabilizer. The results also showed that a temperature range 340350°C, where most of the chlorine for all types used in the tests was released, is optimal for operating the BFB pyrolysis reactor.
04/02978 The effects of particle characteristics on emissions from burning wood fuel powder Paulrud, S. and Nilsson, C. Fuel, 2004, 83, (7-8), 813-821. Wood fuel powders cut in different mills were combusted in a 150 kW burner to study emissions, furnace temperature and burnout as a function of particle size distribution and particle shape. Particle characteristics only slightly influenced NOx formation but more strongly influenced fuel feeding, ignition, unburned pollutants and furnace temperature. The lowest NOx emissions achieved was < 50 rag/ MJ. For finely milled wood powder, CO emissions had the lowest values (2I mg/MJ). Varying the ratio between primary, secondary and tertiary airflows, slightly influenced the combustion results using a small-scale powder burner.
04/02979 Thermally-stable refractory shotcrete material for repairing coke-oven wall linings Berkutov, N. A. et al. Russ. RU 2,203,249 (CI. C04B35/65), 27 Apr 2003, Appl. 2,001,118,909. (In Russian) The invention is suitable in the manufacture of refractory materials intended for hot repair of coke-ovens. The shotcrete refractory material contains quartzite 82-86, silicon 12-16, aluminium 1.2-1.7, and feldspar 0.5-1 weight %. This mixture is deposited onto the lining with the flow of oxygen, natural gas, or their mixture. The resulting composition provides enhanced repair efficiency, and exhibits temperature stability up to 1500 °. Compressive strength of the material is 23-26 MPa.
04/02980 Transformation of mineral and emission of particulate matters during co-combustion of coal with sewage sludge Ninomiya, Y. et al. Fuel, 2004, 83, (6), 751-764. Co-combustion of coal with sewage sludge was carried out in laboratory-scaled drop tube furnace to understand the interaction between different fuels. The combustion conditions were selected as follows: the raw material feeding rate was 0.2-0.3 g/rain, temperature was 1200°C, the atmosphere of 10% 02 and N2 being balance was used to guarantee an air ratio of 1.5, and the residence time varied from 0.6 to 2.4 s. The coal/sewage sludge is kept at 50:50 (wt% to wt%), four fuel pairs were selected with respect to the mineral association within individual fuel. The results showed the obvious interaction between coal and sewage sludge during their co-combustion. For the carbon conversion, the devolatilization of mixing fuel occurred quickly; the combustion of both char and evolved volatile progressed almost completely. As a result, the un-burnt carbon was almost zero in the fly ash. In addition, the evolution of both mineral and PM varied with the association of minerals in raw fuels. For both coal and sewage sludge rich in included minerals, they combusted separately in the furnace, less interaction occurred accordingly. Conversely, for both them rich in excluded minerals, the minerals reacted with each other to form much agglomeration, and therefore, the particle size of the fly ash was increased, while the amount of PM was decreased, which changed as the coarse fly ash particles. Finally, for the case of coal rich in excluded mineral and sludge rich in included mineral, their cocombustion led to the interaction of their minerals. As a result, more the fine particles were formed, which in part changed into PM. For the vaporized trace elements, they were adsorbed by the melt CaPO4/AI-Si