The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Kunio Yoshikawa - One of the best experts on this subject based on the ideXlab platform.

  • gasification performance of coals using High Temperature Air
    Energy, 2005
    Co-Authors: Shinobu Sugiyama, Kunio Yoshikawa, Naoki Suzuki, Yoshitaka Kato, Akira Omino, Toru Ishii, Kouji Yoshikawa, Takashi Kiga
    Abstract:

    MEET (Multi-staged Enthalpy Extraction Technology) system is a new coal/wastes-fired power generation system. In order to establish the MEET system technology, a demonstration plant of commercial scale, MEET-II, was installed. The capacity of the MEET-II is 2 t/day of coal of 4 t/day of RDF. MEET-II consists of a pebble bed slagging-gasifier, a High Temperature Air generator, and a High Temperature Air combustion boiler. Gasification with High Temperature Air results in Higher heating value of syngas. Cleaned-up syngas is used as a fuel for the boiler as well as for preheating Air up to 1000 °C. Combustion and gasification tests at the MEET-II were conducted using pulverized coal as a fuel. Combustion experiments demonstrated almost complete char combustion with a short residence time, and gasification experiments demonstrated targeted calorific value of syngas, 1000 kcal/mN3.

  • Study on Thermal Characteristics of a High Temperature Air Combustion Boiler (2nd Report, Numerical Study)
    Transactions of the Japan Society of Mechanical Engineers Series B, 2003
    Co-Authors: Hiromichi Kobayashi, Kunio Yoshikawa
    Abstract:

    Thermal characteristics of a High Temperature Air combustion boiler is numerically examined. The High Temperature Air combustion is realized using a preheated Air of about 800°C∼1000°C under low oxygen content (∼5%). Numerical simulation reveals that more uniform Temperature distribution in the boiler and Higher heat transfer are obtainable using High Temperature Air in comparison with using normal Temperature Air owing to mild reactions in the High Temperature field and heat recovery by regenerative burners. High speed injection of High Temperature Air into the boiler causes in-furnace exhaust gas recirculation, which results in low NOx emission. There is good agreement between experiment and numerical simulation in particular when using low calorific value gas, because more uniform Temperature distribution is realized and average Temperature in the boiler becomes lower.

  • Development of a High-Temperature Air-blown gasification system.
    Bioresource Technology, 2001
    Co-Authors: Carlson C.p. Pian, Kunio Yoshikawa
    Abstract:

    Current status of High-Temperature Air-blown gasification technology development is reviewed. This advanced gasification system utilizes preheated Air to convert coal and waste-derived fuels into synthetic fuel gas and value-added byproducts. A series of demonstrated, independent technologies are combined to form the core of this gasification system. A High-Temperature, rapid devolatilization process is used to enhance the volatile yields from the fuel and to improve the gasification efficiency. A High-Temperature pebble bed filter is used to remove the slag and particulates from the synthetic fuel gas. Finally, a novel regenerative heater is used to supply the High-Temperature Air for the gasifier. Component development tests have shown that Higher gasification efficiencies can be obtained at more fuel-rich operating conditions when High-Temperature Air is used as the gasification agent. Test results also demonstrated the flex-fuel capabilities of the gasifier design. Potential uses of this technology range from large-scale integrated gasification power plants to small-scale waste-to-energy applications.

Jun'ichi Sato - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of low NO emission in High Temperature Air combustion for pulverized coal
    Fuel, 2004
    Co-Authors: Toshiyuki Suda, Makoto Takafuji, Tetsuya Hirata, Jun'ichi Sato
    Abstract:

    High Temperature Air combustion experiments for pulverized coal in a large-scale furnace have been done before and shown that the NO emission in the High Temperature Air combustion is significantly lower than that in the normal Temperature Air combustion. This paper numerically studies the NO evolution in the large-scale experiments with a simplified chemical reaction model. Through an analysis of numerical results a low NO emission mechanism in the High Temperature Air combustion has been presented. If the HCN concentration is High, the NO generation is fast. But, the High HCN and NO concentrations together will make NO destruction fast. It is found that, by properly arranging flow patterns, the High HCN and NO concentrations can be obtained in the vicinity of primary Air nozzle. Thus, the generation and destruction of NO can reach an equilibrium point so that the net NO emission rate is low.

  • A study of combustion behavior of pulverized coal in High-Temperature Air
    Proceedings of the Combustion Institute, 2002
    Co-Authors: Toshiyuki Suda, Makoto Takafuji, Tetsuya Hirata, Motoki Yoshino, Jun'ichi Sato
    Abstract:

    High-Temperature Air combustion is a promising technology to increase the usage of combustion energy and to improve combustion efficiency. This technology has been mainly developed for gaseous fuels, and recently application of this technology to solid fuels like pulverized coal has also become of interest. For the development of High-Temperature Air combustion technology for pulverized coal, it is important to experimentally investigate the combustion behavior of pulverized coal in High-Temperature Air. In this study, High-Temperature Air is applied to a pulverized coal burner to investigate the effect of Air Temperature on ignition, coal burnout, and NO x emission. Pulverized coal is introduced into a cylindrical furnace of 1 m diameter and 3 m height using a water-cooled stainless nozzle of 15 mm diameter. Combustion Air is preheated using a heat exchanger with a gas burner and electrical furnace. The Temperatures of the combustion Air are set to 623 or 1073 K in order to compare the effect of Air Temperature. It is observed that ignition delay decreases as the Air Temperature increases, which is due to the more rapid devolatilization caused by Higher particle heating rates. It is possible to form a stable flame even for low-volatile coals like anthracite. The difference in measured peak flame Temperatures between 623 and 1073 K Air is about 100 K, which is smaller than expected. Coal burnout is improved in the 1073 K Air condition, which seems to be due to the increase of porosity of the particle. NO x concentration decreases for Higher Temperature due to enhancement of the reduction zone by rapid devolatilization of coal, as the volatile and fuel nitrogen release is enhanced in High-Temperature Air.

  • Numerical study of NOx emission in High Temperature Air combustion
    JSME International Journal Series B, 1998
    Co-Authors: Hongsheng Guo, Kaoru Maruta, Takashi Niioka, Jun'ichi Sato
    Abstract:

    The characteristics of NOx emission in the High-Temperature Air combustion technology were investigated numerically. Two kinds of methods were used. Detailed chemistry and transport properties were used for a two-dimensional laminar diffusion flame, and a simplified reaction scheme was used for calculating a turbulent flame in a furnace. Results show that the thermal mechanism dominates NOx emission in High-Temperature Air combustion. If only the preheated Air Temperature is increased, NOx emission will rise significantly. However, the combination of Air preheating and flue gas recirculation not only improves the combustion efficiency, but also suppresses NOx emission in the combustion process.

Guoliang Song - One of the best experts on this subject based on the ideXlab platform.

  • NO emission on pulverized coal combustion in High Temperature Air from circulating fluidized bed – An experimental study
    Fuel Processing Technology, 2009
    Co-Authors: Jianguo Zhu, Tianyu Niu, Guoliang Song
    Abstract:

    Abstract High Temperature Air was adopted by combustion in High excess Air ratio in a circulating fluidized bed. Experiments on pulverized coal combustion in High Temperature Air from the circulating fluidized bed were carried out in a down-fired combustor with the diameter of 220 mm and the height of 3000 mm. The NO emission decreases with increasing the residence time of pulverized coal in the reducing zone, and the NO emission increases with excess Air ratio, furnace Temperature, coal mean size and oxygen concentration in High Temperature Air. The results also revealed that the co-existing of Air-staging combustion with High Temperature Air is very effective to reduce nitrogen oxide emission for pulverized coal combustion in the down-fired combustor.

  • Pulverized coal combustion and NOx emissions in High Temperature Air from circulating fluidized bed
    Fuel Processing Technology, 2008
    Co-Authors: Jianguo Zhu, Tianyu Niu, Guoliang Song
    Abstract:

    Abstract A new technique of achieving High Temperature Air was adopted by combustion in High excess Air ratio in a circulating fluidized bed (CFB). Experiments on pulverized coal combustion in High Temperature Air from the CFB were made in a down-fired combustor with the diameter of 220 mm and the height of 3000 mm. High Temperature Air with lower oxygen concentrations can be achieved steadily and continuously by combustion in the circulating fluidized bed. Pulverized coal combustion in High Temperature Air shows a uniform Temperature profile along the axis of the down-fired combustor and the combustion efficiency is 99.8%. The NOx emission is 390 mg/m3, 13% lower than the regulation for thermal power plants in China. The HCN and NH3 emissions, as well as N2O, are about zero in the exhaust.

Carlson C.p. Pian - One of the best experts on this subject based on the ideXlab platform.

  • High-Temperature, Air-blown gasification of dAiry-farm wastes for energy production
    Energy, 2003
    Co-Authors: Lincoln C. Young, Carlson C.p. Pian
    Abstract:

    A study was carried out to investigate the feasibility of integrating an advanced gasifier into the operation of a dAiry farm for converting biomass wastes into fuel gas that can be used for power production. The disposal/utilization of excess animal wastes is a serious problem facing the dAiry industry. Implementation of a gasification system on the dAiry farm may provide an economical means of disposing of this waste. In our scheme, an advanced, High-Temperature Air-blown gasification system is used to convert the waste into synthetic fuel gas. A ceramic regenerative heater supplies the High-Temperature Air. Results of performance calculations indicated gasification conversion efficiencies of 65–85 % are possible, depending on the gasifier operating configuration. The syngas produced by the gasifier can be used on the farm for generating electricity and heat, or for other energy needs, thus helping to reduce the operating cost of the farm. In a case study, using information collected from an Upstate New York dAiry farm, the results showed that gasification of dAiry wastes would allow this particular farm to produce more than two times the amount of energy required for self-sufficiency.

  • Development of a High-Temperature Air-blown gasification system.
    Bioresource Technology, 2001
    Co-Authors: Carlson C.p. Pian, Kunio Yoshikawa
    Abstract:

    Current status of High-Temperature Air-blown gasification technology development is reviewed. This advanced gasification system utilizes preheated Air to convert coal and waste-derived fuels into synthetic fuel gas and value-added byproducts. A series of demonstrated, independent technologies are combined to form the core of this gasification system. A High-Temperature, rapid devolatilization process is used to enhance the volatile yields from the fuel and to improve the gasification efficiency. A High-Temperature pebble bed filter is used to remove the slag and particulates from the synthetic fuel gas. Finally, a novel regenerative heater is used to supply the High-Temperature Air for the gasifier. Component development tests have shown that Higher gasification efficiencies can be obtained at more fuel-rich operating conditions when High-Temperature Air is used as the gasification agent. Test results also demonstrated the flex-fuel capabilities of the gasifier design. Potential uses of this technology range from large-scale integrated gasification power plants to small-scale waste-to-energy applications.

  • Biomass-fueled, High-Temperature, Air-blown gasification systems
    Collection of Technical Papers. 35th Intersociety Energy Conversion Engineering Conference and Exhibit (IECEC) (Cat. No.00CH37022), 2000
    Co-Authors: Carlson C.p. Pian, K. Yoshikawa
    Abstract:

    Several aspects of using an advanced, High-Temperature Air-blown gasification system for converting biomass wastes into fuel gas are examined, The gasification system, known as MEET (multi-staged enthalpy extraction technology), has many features that are advantageous for biomass power generation. The low-cost gasifier is extremely compact and flexible, capable of operating efficiently on a wide range of low caloric-value biomass fuels. It also has the ability to use fuels that are High in alkali-metal concentrations. The performance of the MEET gasification system is assessed for several common biomass fuels, including sawmill wood wastes, grass, and partially composted cow manure.

Toshiyuki Suda - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of low NO emission in High Temperature Air combustion for pulverized coal
    Fuel, 2004
    Co-Authors: Toshiyuki Suda, Makoto Takafuji, Tetsuya Hirata, Jun'ichi Sato
    Abstract:

    High Temperature Air combustion experiments for pulverized coal in a large-scale furnace have been done before and shown that the NO emission in the High Temperature Air combustion is significantly lower than that in the normal Temperature Air combustion. This paper numerically studies the NO evolution in the large-scale experiments with a simplified chemical reaction model. Through an analysis of numerical results a low NO emission mechanism in the High Temperature Air combustion has been presented. If the HCN concentration is High, the NO generation is fast. But, the High HCN and NO concentrations together will make NO destruction fast. It is found that, by properly arranging flow patterns, the High HCN and NO concentrations can be obtained in the vicinity of primary Air nozzle. Thus, the generation and destruction of NO can reach an equilibrium point so that the net NO emission rate is low.

  • A study of combustion behavior of pulverized coal in High-Temperature Air
    Proceedings of the Combustion Institute, 2002
    Co-Authors: Toshiyuki Suda, Makoto Takafuji, Tetsuya Hirata, Motoki Yoshino, Jun'ichi Sato
    Abstract:

    High-Temperature Air combustion is a promising technology to increase the usage of combustion energy and to improve combustion efficiency. This technology has been mainly developed for gaseous fuels, and recently application of this technology to solid fuels like pulverized coal has also become of interest. For the development of High-Temperature Air combustion technology for pulverized coal, it is important to experimentally investigate the combustion behavior of pulverized coal in High-Temperature Air. In this study, High-Temperature Air is applied to a pulverized coal burner to investigate the effect of Air Temperature on ignition, coal burnout, and NO x emission. Pulverized coal is introduced into a cylindrical furnace of 1 m diameter and 3 m height using a water-cooled stainless nozzle of 15 mm diameter. Combustion Air is preheated using a heat exchanger with a gas burner and electrical furnace. The Temperatures of the combustion Air are set to 623 or 1073 K in order to compare the effect of Air Temperature. It is observed that ignition delay decreases as the Air Temperature increases, which is due to the more rapid devolatilization caused by Higher particle heating rates. It is possible to form a stable flame even for low-volatile coals like anthracite. The difference in measured peak flame Temperatures between 623 and 1073 K Air is about 100 K, which is smaller than expected. Coal burnout is improved in the 1073 K Air condition, which seems to be due to the increase of porosity of the particle. NO x concentration decreases for Higher Temperature due to enhancement of the reduction zone by rapid devolatilization of coal, as the volatile and fuel nitrogen release is enhanced in High-Temperature Air.