Secondary Combustion Chamber Research Articles

3D investigation of heat exchange and hydrodynamics of high pressure turbine nozzle block platforms with different cooling schemes

Turbine nozzle blocks were tested and, as a result, problems of nozzle block lower platform alligatoring were detected. In the course of the research possible variants of cooling high pressure turbine nozzle block vane platforms were investigated. According to the results of 3D ANSYS CFX calculation the cooling efficiency of high pressure turbine vane platforms with film cooling and convective-film cooling were compared. Research was carried out to eliminate the alligatoring defect of the lower vane platform with convective cooling. Necessary changes in the design were made due to which the cooling air from the secondary combustion chamber area was redistributed over the surface of the turbine nozzle block lower platform. To force the gas turbine engine to the inlet gas temperature to 1800К and more, and to increase the cooling air mass flow from the secondary combustion chamber area over the platforms using convective cooling methods not requiring developed ribbing and impingement cooling, areas of the platforms, as well as zones demanding insignificant intensity of cooling are shown.

Impact of fueling protocols on emission outcomes for residential wood-fired appliances

ABSTRACT Many believe that certification testing of residential wood heat appliances should provide data indicative of installed performance. Operationally, test methods typically only assess steady-state emissions and fail to include other typical conditions for batch appliances such as start-up. From a fueling perspective, protocols should ensure a consistent approach reflecting common use practices. Ensuring representative conditions and accurate quantification of emissions requires assessing the impact of different start-up conditions and whether or not start-up conditions affect appliance operation during start-up and beyond. This study evaluated the impact of modifying fuel piece sizes and configurations using a “smart” wood-fired hydronic heater (WHH) cordwood appliance. The appliance represents technologies using software and oxygen sensors to improve performance. Since the study used a “smart” appliance, the results likely reflect the least amount of variability found in a WHH cordwood appliance. The analysis consisted of a series of tests that involved changing one fuel variable per series, including: (1) kindling fuel arrangement in the firebox; (2) fuel piece size; and (3) the amount of kindling and starter fuel used. A goal of the study was to determine how each variable affects emissions performance during start-up and the following steady state load. Testing used a dual-stage combustion cordwood WHH equipped with external thermal storage. Particulate matter (PM), carbon monoxide (CO), and delivered heating efficiency were measured, and visible emissions from the stack and secondary combustion chamber were observed. Replicate tests were conducted for each protocol series to evaluate WHH performance reproducibility. These tests found that for a low-mass staged combustion WHH with external thermal storage, the use of different fueling protocols can substantially affect PM and CO emissions. Implications: As test methods move to incorporate measurements beyond steady-state emissions, fueling protocols must be assessed to determine (1) if they reflect typical field procedures and (2) the impact of start-up procedures on the complete test run. This paper assessed how changing start-up conditions affected run variability and PM emission impacts.

Formation and control of dioxins during thermal desorption remediation of chlorine and non-chlorine organic contaminated soil

Formation and emission of dioxins is a great concern during thermal desorption remediation of organic contaminated soil. The differential formation of dioxins from chlorine organic contaminated soil (COCS) and non-chlorine organic contaminated soil (NCOCS) is still unclear and the control technique for the dioxins generated is an urgent need. In this study, the formation and distribution characteristics of dioxins were investigated in the thermal desorption unit combined with flue gas purification system during COCS and NCOCS treatments. Although organic contaminates were well desorbed, de-novo formation of dioxins was observed for both COCS and NCOCS, as well as synthesis from precursors for NCOCS. The gas-phase dioxin in the flue gas purification system continuously decreased during NCOCS thermal desorption, while the dioxin concentration in the quench tower sharply increased from 0.46 to 2.13 ng/Nm3 through de-novo synthesis during COCS treatment. Furthermore, the emission of dioxins only slightly reduced (for COCS) or even increased (for NCOCS) at 70% operating load. The catalytic adsorption tower within modified activated carbon and V5-Mo5-Ti catalyst after bag filter can reduce the emission of dioxins up to 91.4% at the condition of secondary combustion chamber closure, demonstrating that the catalytic adsorption tower can replace the secondary combustion chamber for controlling dioxin emission. More importantly, the highly toxic low-chlorinated polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/PCDFs) were selectively removed from flue gas by the catalytic adsorption tower. These results reveal the differential formation characteristics of dioxins during COCS and NCOCS thermal treatments and highlight V5-Mo5-Ti/ modified activated carbon as a promising catalytic adsorption material to control the emission of dioxins from the thermal desorption of organic contaminated soil.

Formation and Growth Behavior Analysis of Slagging Rings in Rotary Kiln-Type Hazardous Waste Incineration Systems

Rotary kiln incineration technology has the advantages of strong material adaptability and a simple treatment process and has been widely used in hazardous waste treatment. However, the actual incineration process has caused problems such as ring formation in the treatment system due to the lack of research on the slagging mechanisms. In this paper, slagging phenomena occurring in the second half of the rotary kiln, the exit flue of the secondary combustion chamber, and the wall of the quench tower are analyzed and discussed in detail through characterization methods. The results indicate that the adhesion of low-melting alkali metal salts on the refractory surface in the second half of the rotary kiln is the key factor in forming the initial slagging layer. In the growth process of the slagging ring, the formed liquid phase can bond incineration residues of different sizes together and form a dense embryo body through liquid phase sintering. The deposition and solidification of molten/semi-molten fly ashes cause slagging formation in the exit flue of the secondary combustion chamber. The slagging phenomenon occurring in the inner wall of the quench tower belongs to the “crystalline-coalesce-hardening” process of the inorganic salts precipitating out of the high-salt wastewater.

Comparative Studies on the Ablation/Erosion Mechanisms of Silicone Rubber Composites under Erosion of Different Particles by New Testing Method

Abstract The performance of solid rocket ramjets is affected by the ablation resistance of silicone rubber composites in the secondary combustion chamber. To investigate the ablation mechanisms of silicone rubber composites in multiphase flow environments, a new ablation testing methodology, in which particles can be added to the flame, is developed in this investigation. Boron oxide (B2O3) and alumina (Al2O3) particles were used to simulate condensed-phase particles. The experimental results show that because of the high hardness and melting point of Al2O3, the mechanical destruction of the Al2O3 particles was so intense that the surface of silicone rubber composite was completely destroyed, and the matrix was exposed to the surface. The surfaces of the B2O3 particles melted and evaporated in the flame, forming a liquid layer, similar to condensed-phase particles in the secondary combustion chamber of solid ramjet. After the ablation of silicone rubber under the erosion action of B2O3 particles, a char layer and pyrolysis layer were formed, similar to the scenario during the actual ablation of silicone rubber composites. The multiphase flow environment with B2O3 particles can truly reflect the ablative environment experienced by silicone rubber composites.

Cyclone-Bed Furnaces: Experimental Studies and Thermal Design

Furnace processes occurring in laboratory setups, pilot commercial facilities, and small-capacity boilers of various sized equipped with cyclone-bed furnaces containing fixed and fluidized beds burning solid biofuels (wood pellets, straw pellets, sunflower husk pellets, peat pellets, wood waste, wood chips, milled peat, and crushed peat bricks) are investigated. The distribution features of temperature and gas concentrations (CO, CO2, H2, O2, CH4) in the combustion and secondary combustion chambers have been established in the course of experiments. With this information available, it becomes possible to determine the zones in which fuel actively reacts with the oxidant under the conditions of two-stage vortex combustion. Dependences of the carbon monoxide (CO) and nitrogen oxide (NOх) concentrations in the flue gases on the excess air ratio, bottom blast share (primary air), furnace power, and the combustion chamber’s outlet hole diameter are obtained. The furnace processes in cyclone-bed furnaces are numerically simulated using the standard k–e turbulence model and the Magnussen combustion model, and satisfactory agreement between the calculation and experimental results is shown. A semiempirical method for designing cyclone-bed furnaces has been developed, according to which their main geometrical and operating parameters are determined in two stages: a preliminary thermal design analysis is first carried out, after which the furnace process is numerically simulated. Based on extensive generalization of experimental data on the burning of solid biofuels in cyclone-bed furnaces having different diameters, the parameter М = 0.52, which appears in the well-known Gurvich formula for the thermal design of furnace chambers, has been determined. This parameter takes into account the temperature field structure and the heat transfer pattern over the furnace height, thus making it possible to use the standard method in carrying out thermal design computations of furnaces.

The impacts of different profiles of the grate inlet conditions on freeboard CFD in a waste wood-fired grate boiler

The common combustion disturbances in the fuel bed in a grate-fired boiler pose a great challenge to accurate modelling of the fuel bed conversion. Therefore, it is difficult to describe the lengthwise profiles of the combustibles leaving the fuel bed into the freeboard accurately. This paper investigates how different fuel bed models or grate inlet profiles will affect the Computational Fluid Dynamics simulation of combustion in the freeboard in industrial grate boilers. Two grate inlet conditions, which are very different in the profiles along the grate but yield the same total mass, momentum, species and energy fluxes into the freeboard, are used in the freeboard simulation of a 13 MWth grate boiler, respectively. The key findings from the comparison between the simulation results and measurement data are as follows. Firstly, the fuel bed model or grate inlet condition accounting for the realistic lengthwise biomass conversion pattern can be used reliably for the simulation of a grate boiler and simulation-based boiler optimisation. Secondly, the impacts of different fuel bed models or different profiles of the grate inlet conditions are virtually restricted only to the vicinity of the fuel bed or in the primary combustion chamber. After the secondary combustion chamber in which up-flowing gas is mixed well with the secondary and tertiary air jets, the simulation results are close to each other. For more general and reliable applications, a comprehensive bed model resolving the mixing, reactions, heat and mass transfer in the fuel bed, is needed and under development.

Emission characteristics of dl-PCNs, PCDD/Fs, and dl-PCBs from secondary copper metallurgical plants: Control technology and policy

This study investigated the characteristics of dl-PCNs, PCDD/Fs and dl-PCBs emitted from two typical secondary copper metallurgical plants processing copper sludge equipped with different sets of air pollution control devices (APCDs). Results indicated that the emission factors of dl-PCNs and PCDD/Fs of plant A are 0.00775 and 1.09 μg TEQ/ton, respectively, which are remarkably lower than those of plant B (3.12, 181 and 25.5 μg TEQ/ton for dl-PCNs, PCDD/Fs and dl-PCBs, respectively). Dl-PCNs contributed 0.7–2.7% of total TEQ for flue gases and up to 2.6% of TEQ for ash samples. The TEQ concentration of dl-PCNs in fly ash individually exceeds the regulated level of 1 ng TEQ/g regulated by Taiwan EPA, indicating that emission and discharge of dl-PCNs should be regulated. The combination of semidry scrubber and activated carbon injection (ACI) + baghouse (BH) is effective for simultaneous removals of dl-PCNs and PCDD/Fs in plant A; while the combination of cyclone, secondary combustion chamber, ACI + BH and wet scrubber (WS) is not optimal for removing dl-PCNs, PCDD/Fs and dl-PCBs. Memory effect occurring within BH and WS is responsible for low removal efficiencies of these POPs in plant B. This study suggests appropriate APCDs for simultaneous removal of three POP groups and recommends the inclusion of dl-PCNs in emission standard.

Pyrolysis of Radioactive Spent Resins in the PRIME Installation

Montair and Belgoprocess developed the pilot PRIME (Pyrolysis Resins In Mobile Electric) Installation for treatment of spent resins in one single reactor without pre-treatment and without intermixing of other waste, allowing for easy traceability and isotopic characterization of the end product. Both low level waste (LLW, < 2 mSv/h) and medium level waste (MLW, > 2 mSv/h) can be treated in the installation. The PRIME pilot installation is designed to treat 2 batches of 100 litre of saturated ion exchange resins over a period of 24 hours. The pyrolysis reactor contains a special design mechanical stirrer and can operate at a temperature of up to 600°C under inert conditions. As a result, the organic molecules will decompose at an accelerated rate until only carbon-rich and mineralised product free of hydrocarbons remains. Gases that are released during drying and pyrolysis are treated in a thermal oxidizer, which uses an innovative, electrically heated design instead of a traditional natural gas- or fuel oil secondary combustion chamber design. After passing through the thermal oxidizer, the gases are cooled down to saturation temperature and treated in the wet scrubbing system. An induced draft fan keeps the system under negative pressure to prevent the possibility of any off-gas leakage out of the system. The pyrolysing reactor and oxidiser are fully electrically powered which creates also a higher safety level. A series of tests were performed successfully with wet cationic resins, anionic resins and a mixture of both. The results of these tests are described in the presentation. For intellectual property protection, the system and process of pyrolysis of organic waste and the system of thermal oxidation of pyrolysis gases described in this paper are patent pending.

Emission Characteristics and Formation Pathways of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans from a Typical Pesticide Plant

ABSTRACT The emission characteristics and the formation pathways of the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from a pesticide plant were well investigated. In the present study, the international toxic equivalent quantity (I-TEQ) value of the PCDD/Fs (0.087 ng I-TEQ Nm–3) in the flue gas at the outlet of stack can meet the emission limit (0.1 ng I-TEQ Nm–3). The I-TEQ value of the PCDD/Fs (3.25 pg I-TEQ g–1) in the fly ash is much lower than the permitted standard for disposal in sanitary landfill sites (3.0 ng of I-TEQ g–1). In addition, 1,2,3,4,6,7,8-HpCDD, OCDD and 1,2,3,4,6,7,8-HpCDF are the three main congeners in the PCDD/Fs for the outlet of both the secondary combustion chamber and the stack. 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD and OCDD are the most dominant congeners for the PCDD/Fs from inlet of bag filter. PCDD/Fs may be formed through high temperature homogeneous synthesis and heterogeneous precursor synthesis in the flue gas. In addition, PCDD/Fs might be formed in bag filter via de novo synthesis. The main formation areas of PCDD/Fs are waste heat boiler and quenching/deacidification tower in this pesticide plant. The TEQ estimated emissions of PCDD/Fs reaches 9.3 g year–1. These findings are helpful for further controlling the formation and emission of PCDD/Fs in pesticide plants, yet more studies are still required.

Kaolinite induced control of particulate lead and cadmium emissions during fluidized bed waste incineration

AbstractKaolinite was utilized as in‐furnace sorbent to control submicron lead (Pb) and cadmium (Cd) emissions during waste incineration in a fluidized bed furnace. The secondary combustion chamber temperature ranged from 850 to 1000 °C. The metal capture was investigated for aspects of chemical reaction, physical conglutination and control performance of submicron metal emission. Pb reacted with kaolinite and caused conglutination of nanoscale metal particles at a lower temperature than Cd. Emission control of submicron Pb was far more effective than that of submicron Cd, particularly below 950 °C. For both Pb and Cd, there was capture limitation and an increase of kaolinite fraction above 3% could not further reduce the submicron metal emission. According to toxicity factors (5 Pb = 1 Cd) and the leaching fraction of submicron particles, the comprehensive performance of kaolinite was evaluated and numerous contradictory results were obtained. © 2017 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

Corrosion of Al2O3-SiO2 refractories by sodium and sulfur vapors: A case study on hazardous waste incinerators

While incinerators are important for eliminating hazardous waste from industry, there are few publications on the corrosion of secondary combustion chambers. The sudden refractory failure results in high costs and work stoppages. Thus, corrosion in fireclay and bauxite-clay refractories exposed for 50 months to the harsh atmosphere in the chamber (H2O, O2, CO2, SO2, HCl, alkali vapors, etc.) was investigated. The operating temperatures of 930–1000°C heat the inner refractory face up to 950°C and the exterior face to 750°C. X-ray diffraction revealed that condensed alkali and sulfur compounds interacted with refractories. Thermodynamic calculations determined the critical chemical reactions. Our findings show a successive corrosion mechanism that starts with the condensation of thenardite (Na2SO4) and finishes with expansive phases. In fireclay bricks, the reaction with free silica led to liquid phases and slow creep. Sudden lining breakdowns were provoked by nepheline and nosean. Contrary to expectations, nepheline was not formed in the bauxite-clay bricks. Instead, only nosean was formed. In the literature, under laboratory conditions, no nosean has been observed in hot corrosion experiments. Perhaps, nosean requires several months to years to form inside the secondary combustion chamber. Our work indicates that to impede these corrosion processes, refractories should contain as little silica as possible.

Technical and economic analysis of using biomass energy

In the first part of the article were presented the technical possibilities of obtaining solid biomass, biogas, landfill gas, a biogas from wastewater treatment plants, bioethanol and biodiesel. Then processes was described, allowing use of energy from biomass. As first was discussed the incineration which includes drying and degassing of the wood materials, wood gas burning at 1200°C, post-combustion gas and heat transfer in the heat exchanger. Then had been described gasification, or thermochemical conversion process, occurring at high temperature. It is two-stage process. In the first chamber at deficiency of air and at relatively low temperatures (450–800°C), the fuel is being degasified, resulting in creating combustible gas and a mineral residue (charcoal). In the second stage, secondary combustion chamber and at a temperature of about 1000–1200°C and in the presence of excess of oxygen resultant gas is burned. A further process is pyrolysis. It consists of the steps of drying fuel to a moisture level below 10%, milling the biomass into very small particles, the pyrolysis reaction, separation of solid products, cooling and collecting bio-oil. Then discusses co-generation, which is combined production of heat and electricity. In this situation where the biomass contains too much water it can be used for energy purposes through biochemical processes. The alcoholic fermentation results in decomposition of carbohydrates taking place under anaerobic conditions, and the product is bioethanol. Another biochemical process used for the production of liquid biofuels is esterification of vegetable oils. Methane fermentation in turn causes a decomposition of macromolecular organic substances with limited oxygen available. As a result, we obtain alcohols, lower organic acids, methane, carbon dioxide and water. There was analysis of economic increasing of solid biomass energy, biogas and liquid biofuels in the following article.

Green, Eco, Innovative Design, and Manufacturing Technology of a 1-Ton per Batch Municipal Solid Waste Incinerator

The thermal treatment of waste by incineration is considered an ultimate solution in order to get rid of waste properly by using the combustible properties of waste and transforming them into inert form and gaseous emission, with the main advantage of a huge reduction in mass and volume of treated waste, destruction of the dangerous components in waste, and obtaining green and clean energy from the exothermal reaction from the completed combustion process. In order to achieve the main goal of incineration, a good design, construction, supervision, and intensive operation and maintenance must be taken into account, especially for the small-scale incinerator. This research will deal with the green, innovative, and eco design and manufacturing technology of a 1-ton per batch municipal solid waste (MSW) incinerator. The concept design of the incinerator will focus on the design of the feeding process where only one batch of waste will be discharged into the combustion chamber at one time instead of the semi-feed process, as found in the conventional incinerator. This will ease the operation of the operator and reduce the operating cost. Moreover, the innovative design includes the redesign of combustion air injection into either the primary or secondary combustion chamber in order to achieve the 3Ts of combustion (time, temperature. and turbulence). This design can eliminate the use of an auxiliary burner in the primary combustion chamber. Rethinking the innovative design of using recirculation hot flue gas for preheating of wet garbage in order to pre-dry the waste before combustion is also taken into account. The manufacturing process of the wall composition as well as other parts of the incinerator are also examined.

Innovative Design and Manufacturing Technology of High Temperature Air Combustion (HTAC) Municipal Solid Waste Incinerator

Incineration is a Thermal Treatment Technology (3Ts) that could be expressed as the way to get rid of waste effectively with the reduction of its mass and volume. However, to control the combustion process efficiently, especially combustion temperature, with low energy content in Municipal Solid Waste (MSW), an additional fuel is needed and leads to increase of operating cost compared with other disposal option. High Temperature Air Combustion (HTAC) has been successfully demonstrated in a lab-scale incinerator for energy saving and pollutant reduction, especially NOx. This article has the objective to design and manufacture the prototype scale High Temperature Air Incinerator with a capacity to treat MSW of 12 Ton per day. The system consists of an automatic feeding machine to feed the waste into the primary combustion chamber (PCC) where the combustion takes place. The push ram is used to push the burning waste and fall down to the lower hearth. Primary combustion air is supplied into PCC at the amount lower than the stoichiometric requirement to produce the combustible gas which is flown into the Secondary Combustion Chamber (SCC) located above PCC. Secondary combustion air is injected to react with combustible gas to convert to the product of complete combustion. A part of hot flue gas which is flew out from SCC is reverted and mixed with fresh air, in order to reduce oxygen concentration, before passing through the heat exchanger tube bundle which is placed inside SCC in order to exchange heat with hot flue gas. To manufacture the designed incinerator, the detail of materials used as well as the frabication method is explained. It has been shown that HTAC can be applied for thermal destruction of waste successfully, in term of energy saving and pollutant free. Benefits of this research work will promote the using of thermal treatment technology of dispose of MSW with lower operating cost and lower pollutants.

Thermal treatment of medical waste in a rotary kiln

This paper presents the results of a study of an experimental system with thermal treatment (incineration) of medical waste conducted at a large complex of hospital facilities. The studies were conducted for a period of one month. The processing system was analysed in terms of the energy, environmental and economic aspects. A rotary combustion chamber was designed and built with the strictly assumed length to inner diameter ratio of 4:1. In terms of energy, the temperature distribution was tested in the rotary kiln, secondary combustion (afterburner) chamber and heat recovery system. Calorific value of medical waste was 25.0 MJ/kg and the thermal efficiency of the entire system equalled 66.8%. Next, measurements of the pollutant emissions into the atmosphere were performed. Due to the nature of the disposed waste, particular attention was paid to the one-minute average values of carbon oxide and volatile organic compounds as well as hydrochloride, hydrogen fluoride, sulphur dioxide and total dust. Maximum content of non-oxidized organic compounds in slag and bottom ash were also verified during the analyses. The best rotary speed for the combustion chamber was selected to obtain proper afterburning of the bottom slag. Total organic carbon content was 2.9%. The test results were used to determine the basic economic indicators of the test system for evaluating the profitability of its construction. Simple payback time (SPB) for capital expenditures on the implementation of the project was 4 years.

Thermal utilization (treatment) of plastic waste

This paper presents the results of a pilot study of a thermal utilization installation for incinerating plastic waste. The research was conducted on an industrial scale in a plant that manufactures plastic tape (used for warning, packing and masking purposes, among others). The system was considered in terms of three aspects: energy, environmental and economic. Due to the very high LCV (lower calorific value) of the waste, an innovative rotary combustion chamber (rotary kiln) was employed. The experimental installation was analysed in terms of the temperature distribution in the rotary kiln, secondary combustion (afterburner) chamber and heat recovery system. The thermal efficiency of the tested installation was determined. The emissions into the atmosphere were measured and compared with the applicable emission standards. Due to the nature of the waste, particular attention was paid to emission analysis of carbon oxide and volatile organic compounds. In terms of the economic aspect, fundamental economic indicators were found for the tested system to determine the profitability of its construction.

Analysis of the biomass gasification-based shape of the crematory’s secondary chamber by using Computational Fluid Dynamics

This paper describes the simulation result of biomass gasification-based crematory's secondary combustion chamber via CFD analysis. The chamber models, which were rectangular and cylinder type, were implemented, whereas ANSYS FLUENT with standard k-omega viscous model and SIMPLE algorithm were taken place. The results show that an average residence time of gas and particle if simulating by using rectangular chamber displays as 2 and 3 second, respectively, whereas the average residence time of cylinder chamber type presents 2 second for particle and 4 second for gas. Furthermore, the residence time of cylinder chamber type can be increased by lengthening the chamber's height, which the benefits, such as efficient pollution control, will be earned.

Numerical Simulation on Two Phase Combustion Characteristic in Solid Rocket Ramjet Afterburning Chamber

Numerical simulation on two-phase combustion characteristic in afterburning chamber of solid rocket ramjet was carried out by applying particle trajectory model. It was analyzed that the nozzle number of secondary combustion chamber, inlet angle of air and particles diameter impact on efficiency of combustion. Results show that the combustion efficiency in the afterburning chamber is highest, achieving 99.6% when the angle between both air inlets is 180°, particle diameter is 15μm, and 5-hole nozzle is used. By contrary, when the angle between both air inlets is 90°, particle diameter is 5μm, and 5-hole nozzle is used, the afterburning chamber has a lowest combustion efficiency of 70.3%.

A15 薪ボイラを用いた木質バイオマス燃料スターリングエンジン発電システムの実証試験(スターリングサイクル機器及び関連要素と応用システム(4))

Woody Biomass is defined as a new energy and desired to utilize an energy source beneficially. The authors present a power generation system constructed by a firewood boiler and a Stirling engine generator, The firewood boiler using gasification combustion has a maximum incineration capacity of 20kg/h and a power consumption of 400W. The Stirling engine generator is built up as a 2 piston type engine with driving mechanism including a PM synchronous generator. It is installed in a secondary combustion chamber of the firewood boiler and heated by combustion gas. This paper describes the examination results of the system using a firewood of Japanese oak as fuel. The power generation of 534W and the heat supply capacity of 33.6kW are obtained.