Since the oil crisis in 1973, IGCC R&D has significantly promoted in the worldwide. In 1984, the first commercial scale IGCC demonstration plant was operated at the Cool Water thermal power station in the United States. In Japan, the 200t/d IGCC Pilot Plant Project had started in 1986 with adoption of the air blown entrained flow type gasifier by the Engineering Research Association for Integrated Coal Gasification Combined Cycle Power Systems (IGC Association). Through the trouble shooting and modification of the gasifier, the Pilot Plant achieved 789 hours of continuous operation. Due to the knowledge and experience of early IGCC pioneers, the first Japanese IGCC Demonstration Plant is now under operation successfully. The Demonstration Project is being executed by Clean Coal Power R&D Co., Ltd. A long term continuous operating has already been achieved in 2008, and it is advanced well aiming at commercial plant.

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The flue gas multi-pollutants simultaneous removal is an inevitable trend in the field of flue gas purification. In our researches, the AC technology, the multi-stage humidifier semi-dry technology, the CRS plasma technology and the additive oxidization technology were investigated. The V_2O_5/AC is highly active for the SCR reaction at low temperature. NO_x conversion increased with increasing NO_2/NOR ratio and the catalyst can achieved the highest activity at a temperature as low as 150℃. The semi-dry flue gas cleaning technology can achieve high multi-pollutants removal efficiency through the multistage humidification and the improving additives. The removal efficiencies of SO_2, NO_x and Hg can reach 95%, 41% and 73% respectively in the practice project. The alkali solution absorption basing on the CRS oxidization can achieve high deSO_2 and deNO_x removal efficiencies. In addition, the additive oxidation technology using NaClO_2 can obtain the removal efficiency of near 100% SO_2 and above 80% NO_x.

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Information on the United States (US) Electrical Power Industry current major developments is provided, including: >Electricity use is expected to decline in 2009 and to increase moderately in the future. >Many of the plans for new coal unit units that were planned about 3 to 6 years ago have been set aside. >Most recent new generation has been natural gas combustion turbine/combined cycle plants. >The past two years have seen a surge in the installation of new renewable generating capacity, mostly wind turbines. >New nuclear units are currently in the planning phases and one is being constructed. >New transmission line capacity is being planned to improve the current restrictive situation.

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Mitsubishi Heavy Industries (MHI) G series gas turbine is the industry pioneer in introducing steam cooling technology for gas turbines. The first M501G unit started commercial operation in 1997 and to date, with 62 G units sold, MHI G fleet is the largest steam cooled fleet in the market. The existing commercial fleet includes 35 units with more than 734,000 accumulated operating hours, and over 9,400 starts. Upgraded versions have been introduced in the 60 and 50Hz markets. Several advanced technologies such as TBC with the application of an F class air-cooled system will result in an upgraded air-cooled G class engine with increased power output and enhanced efficiency. This upgraded machine represents a better match for highly cyclic applications, while the highly reliable steam-cooled counterpart is still offered for base-loaded applications. This article describes the design features and verification test results and plan of the upgraded M501 G gas turbine.

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The Kyoto Protocol has come into effect in February 2005 in an effort to reduce global warming. It is necessary for Japan to reduce 6% of the total CO_2 emission of 1990 in Japan from 2008 to 2012. In such an environment, improvement of the thermal efficiency of the gas turbine for GTCC is highly required. Mitsubishi Heavy Industries, Ltd. participates in the national project developing 1700degC gas turbine technology. In this national project, selected component technologies are investigated in detail. Key technologies for 1700degC gas turbine are determined and under development such as, (1) Combustor with exhaust gas recirculation system, (2) Turbine cooling technology, (3) Super heat resistant material, (4) Thermal barrier coatings, (5) High efficiency high loading turbine and (6) High pressure high efficiency compressor. Current status of the technology developments is reviewed.

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Low pressure experiments were performed to better understand the effects of the dilution zone parameters in a DLN combustor on the exit temperature profile. The results show that the temperature uniformity deviates significantly from the design radial profile at full load. Enlargement of the dilution hole size reduces the pattern factor more than the profile factor, but results in a temperature increase near the wall on both sides because of the small circumferential spacing of the dilution holes. Reducing the dilution hole diameter in the lower part of the liner slightly increased the temperature at the blade root. The tests show that the mainstream flow suitably divided is the primary consideration for designing the dilution holes. The main jet holes should be the B holes, not the A holes which do not effectively change the heat flux distribution. A 12% reduction of the pilot fuel ratio made the temperature profile reasonably agree with the design.

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Microturbines have been developed as compact gas turbines to be applied in the re-generative Brayton cycle. A typical microturbine is composed of a centrifugal compressor and a radial inflow turbine. As such, the microturbine has a starting characteristic peculiar to radial inflow turbines. An idling state known as the windage point for mass flow rate can be formed because of improper inlet flow conditions for turbine expansion flow. The present study looked at the relationships between the radius ratio of the radial inflow turbine to the centrifugal compressor and the starting characteristic, and at the effects of turbine inlet flow conditions on the starting characteristic. Fundamental equations for the relationships between the radius ratio and the starting characteristic were obtained. Effectiveness of the equations was compared with experiment results obtained with a 150 kW class prototype microturbine.

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Under high temperature combustion, it is foreseen that very high levels of NOx are generated. In order to suppress the NOx increase, the Exhaust Gas Recirculation (EGR) system is applied to heavy duty gas turbine. The EGR system in a Gas Turbine Combined Cycle recirculates exhaust gas from the Heat Recovery Steam Generator outlet to the compressor inlet. This reduces the oxygen content of the mixed products of combustion with fresh air and therefore, reduces the NOx formation in the combustor. Unfortunately, the lower burning velocity of the mixture causes flame holding problems that may lead to unstable combustion. A novel combustor has been developed that provides good flame holding characteristics and reduces NOx. Intermediate pressure tests were carried out to confirm the NOx reductions in a simulated EGR environment. The results indicate a sharp decrease in NOx compared to a conventional Dry Low NOx combustor operating at similar high temperature.

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The 3rd generation of Dry Low Emission (DLE) combustion system for 8MW-class gas turbine to guarantee <15 ppm NOx emissions(O_2=15%) was developed and introduced to the production lineup of KAWASAKI Green gas turbine. One of the characteristic design concepts of KHI's DLE system is using supplemental fuel burner in the combustor, which is a kind of combustion staging technology. For the 3rd generation DLE system, the burner design of main and supplemental combustion system were upgraded by means of Computational Fluid Dynamics (CFD) fuel-air mixing and also experimental evaluation. The new designed main and supplemental combustion system showed successful results to achieve the emissions target of the 3rd generation DLE system.

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Low pressure tests were performed to improve the design of a can-annular DLN combustor for the 110 MW-class heavy duty gas turbine being developed in China. The airflow distribution, pressure loss, ignition performance, flame stability, combustion efficiency, exit temperature profile, wall temperatures and emissions were all evaluated when operating with natural gas or oil or both. The results indicate that all the performance indices essentially reached their design specifications except for the NOx emissions. The NOx emissions of 94.33 ppm (15% O_2) at full load are far higher than expected over the entire load range. Future work will explore how to reduce the NOx emissions.

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This paper studies a novel low concentration methane catalytic combustion gas turbine, which can be powered with 1% methane in air. When this technology is developed, it can be used not only to mitigate methane for greenhouse gas reduction, but also to utilize such methane as a clean energy source. The performance characteristics of the catalytic combustion were numerical and experimental investigated. The effect of catalytic combustion on the thermodynamic characteristics of the overall system was conducted. It can be concluded that the inlet temperature and the inlet velocity can significantly influence the thermal efficiency of the thermal cycle.

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The development of a closed cycle gas turbine with super-critical carbon dioxide as a working fluid is under way in order to generate power from waste heat source of a low or intermediate temperature range from industry. Its demonstration test plan using a reduced scale turbomachine is described. Principal specifications follow; net power output of 10kWe and recirculation CO_2 flow rate of 1.2kg/s. Optimized range of compressor inlet temperatures as well as pressure is investigated under the given turbine inlet conditions of 550K and 12MPa respectively. Given these inlet conditions, a suitable type of turbomachine is selected to be radial. Based on the conventional design method assuming ideal gas an optimal dimension of the outer wheel diameter is predicted to be 20mm for compressor and 35mm for turbine under an optimal rotational speed of 100000rpm.

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In pulverized coal fired power plants, it is important to reduce emissions of both NOx and unburned carbon. It is also desirable to use lower grade coal such as sub-bituminous coal with a moisture content higher than 20 %. In this study, the combustion technology for reducing the amount of unburned carbon without increasing NOx emission is investigated using the coal combustion test furnace. It was clarified that emissions of both NOx emission and unburned carbon were reduced by controlling conditions for air injection from a burner and by modifying the injection conditions for multistage air. Furthermore, NOx emission at the exit of the furnace decreased in the in-furnace blending method, which means that sub-bituminous coal is fired by the upper burner and bituminous coal is fired by the middle and lower burners, compared with that in the line blending method, which means that the blending ratios of sub-bituminous coal are equal for all burners. Then, the amount of unburned carbon in the in-furnace blending method was also lower than that in the line blending method.

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This study focuses on the fundamental characteristics of DME combustion aiming at the development of low-NOx combustion technology with exhaust gas recirculation (EGR) under high pressure. DME has high potential of applicability of exhaust gas recirculation even at the high mixing ratio because of its high burning velocity and low ignition temperature. Prior to the high pressure combustion test, the combustion test under an atmospheric pressure was conducted with laboratory-scale 11.6kW combustor, where O_2 concentration and temperature at the combustor inlet was systematically regulated, so that the exhaust-gas recirculation at various mixing ratios was simulated. The maximum EGR ratio is 91% at the initial air ratio λ=1.5 with preheated diluted air at 700K. The NOx emission reduced to 14ppm, which is about 13% of that at EGR=0%. The stable combustion sustains even at low oxygen concentration by preheating diluted-air. The exhaust gas recirculation is effective means especially for DME in reducing NOx emission drastically.

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Spherically propagating laminar and turbulent flames at elevated pressures in a large volume bomb were studied using ethanol-air mixtures. Experiments were carried out at the equivalence ratio 0.8 1.0 and 1.4 varying the initial pressure from 0.10 to 0.50 MPa. Turbulence intensity of the mixture was 0.80 and 1.59 m/s. The unstretched laminar burning velocity, U_l decreased as the initial pressure increased. The ratio of the turbulent burning velocity to U_l increased with increasing the ratio of turbulence intensity to ui and turbulence Karlovitz number. This burning velocity ratio was large for rich flames. Thermo-diffusive effects might be more influential to rich ethanol flames because of the small Lewis number. This burning velocity ratio was also found to increase with increasing initial pressure.

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Automotive emission regulations are becoming more and more stringent. The NOx standards still pose a formidable challenge. As we known, lean combustion is one of the best ways to reduce fuel consumption at part engine load. However, it produces higher NOx emissions. The reasons are high combustion temperature and excess of oxygen in cylinder. Both water-gasoline fuel emulsions and exhaust gas recirculation (EGR) are used to absorb the heat in cylinder and reduce the combustion temperature. This paper introduces the process of intake port modification to develop a lean burn system. It also studies about applicable technique water-gasoline emulsions-used in this engine for reducing the NOx. To reach the lean combustion, the original intake port of a four-stroke spark-ignition (SI) engine was modified to generate tumble by using various flow control baffles. The in-cylinder air motion generated by each configuration was characterized using swirl and tumble flow bench to choose the optimum one. The first test is trying to reach the lean-limit of both original engine and modified one using pure gasoline. After that, this lean burn engine was tested with three different water concentrations of water-gasoline emulsions-5%, 10% and 15% respectively. Test conditions are based on vehicle running at 90 km/h on the high way. The engine torque, fuel consumption, exhaust emissions, and combustion characteristics of all tests were investigated. Water-gasoline emulsion has a positive effect on NOx reduction with a suitable water concentration at 5% by mass. The NOx emissions has been decreased 35.0% approximately in comparison with lean-burn engine using pure gasoline

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The chemically recuperated gas turbine (CRGT) cycle has the following advantages: low heat rejection, high combustion efficiency, low thermal radiation to the flame tube and low contamination in the exhaust .In order to let the combustor burning the chemically recuperated produced pyrolysis gas steadily with high efficiency, we must improve the combustor designing. The numerical simulation method based on CFD is an important method to reduce the combustor research expense, shorten the developing period with the advancing of the computer and the development of numerical simulation, which has been recognized by more and more people and can provide the qualitative guidance for the combustor design. In this paper, the combustion flow fields of a combustor with pyrolysis gas as oil was simulated with FLUENT software. During the numerical simulation, the k-ε turbulence model, a single chemistry reaction system, infinite-rate reaction, up-wind discretization scheme and the SIMPLE algorithm were applied. The effect of the load on the combustion efficiency, excess air ratio, the length of flame, the average temperature of outlet and etc were given. The diameters of primary hole and dilution hole was changed and the corresponding combustion fields were simulated, The effect of the diameter on excess air ratio, the length of flame and the unevenness of outlet temperature field were given. By the numerical simulation in this paper, the characteristic of pyrolysis gas's combustion field was researched. The work of this paper is valuable in optimizing the combustor.

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The traditional design and improvement of burner mainly depends on the test data and empirical for- mula, the improved design based on experiment. Because of testing methods and its' restrictions, it is difficult to gain the details of internal combustion flowing field. So there will not be a satisfied result until repeated testing and modification be completed after the design of the burner being finished. The usage of CFD method to study internal combustion turbulence, proliferation of multi-component, chemical reactions such as complex flow phenomena can provide a powerful reference for the design of stereotypes, it plays an increasingly important role, especially in the combustion technology for preliminary feasibility studies, debugging and optimizing performance in the design. In this paper, combined with a new-style burner, used the commercial software FLUENT, a three-dimensioned numerical simulation of combustion flow field was applied to the burner. The results showed that the process of complicated chemical reaction for the flow, the combustion and exchange of heat and mass in the combustion chamber. The main limitations of the burner were found on the basis of simulation results, and an optimal project was put forward for sequential numerical simulating. The results of optimal numerical simulation showed that those optimal measures were very effective. Achieved the purpose of optimization for combustion and control of the scope of high-temperature areas and so on.

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The use of over-fire air as a means of reducing the concentration of NOR, emitted by boiler, has gradually got popularized in China. A numerical simulation study on the effect of over-fire air on flow, combustion and heat transfer, during full capacity operation of a pulverized coal fired 600MW boiler with cross firing, has been started. Mixture fracture/probability density functions are used to simulate turbulent combustion; a P-1 radiation model is used for simulating radiation heat transfer, the Langrange/Euler's method is used for dealing with momentum, mass and energy exchange between the solid and the gas phase; the single rate model for devolatilization and the kinetics/diffusion limited combustion model for simulating surface combustion of pulverized coal particles. Study results indicate that over-fire air helps the current to spread wider in the furnace, delays the introduction of oxygen during the combustion process; the reducing atmosphere in the furnace gets boosted, and the maximal flame temperature is reduced, which helps to reduce the concentration of emitted NO_x. But on the other hand, the use of over-fire air reduces the combustion efficiency of pulverized coal, Figs 5, Tables 2 and Refs 8.

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Mitsubishi Heavy Industries' (MHI) 15 PPM NOx Dry Low NOx (DLN) combustor technology for 1500℃ G-class gas turbines is presented. Key design improvements are compared to the 25 PPM DLN combustor: A) Inlet aerodynamics, B) Fuel/air mixing, C) Combustor aerodynamics, D) Acoustic resonator. Tests were conducted to verify the new DLN combustor by installing it in a M501G1 gas turbine at MHI's T-Point combined cycle power plant, with more than 1500 special measurements. The results demonstrate the following capabilities: A) Less than 15ppm NOx operation with turn down to 60% load. B) Stable combustion dynamics at all load levels. C) High combustor ignition reliability. D) Suitable for daily start and stop (DSS) operation, E) Good reliability and durability. F) Retrofitable to existing 501G and 701G gas turbines. The combustor is now in mass production as a MHI's standard combustor.

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In partially premixed combustion of gas turbine, the combustion temperature should be lowed in order to reduce NO_x. One solution is lean premixed combustion. However, the problem is that large excess air ratio may make the combustion unstable. A novel combustor with circumferential reverse flow of fuel gas is proposed for settling this problem. A 10kw furnace is established to test performance of this combustor. Three factors such as primary air ratio, position of secondary air, total excess air ratio are studied. The emission characteristics and axial flame temperature distribution are studied. Basing on experimental results, the axial flame temperature and NO_x emission increase with primary air ratio and axial length of second stream, and decrease with total excess air ratio. When the total excess air ratio is larger than 1.05, the combustor presents a lower temperature field and much lower NO_x emission (less than 10 ppm).

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Oxyfuel combustion is expected to be one of the promising systems on CO_2 capture from pulverized-coal fired power plant, and enable the CO_2 to be captured in a more cost-effective manner compared to other CO_2 capture process from the power plant. The demonstration project (Callide Oxyfuel Project) on this field is now under way for applying oxyfuel combustion to an existing plant that is the power generation system in Callide-A power plant No.4 unit with a capacity of 30M We in Australia. One of main objectives of this project is to capture CO_2 from an actual power plant for CO_2 storage. At present, the studies toward the commercialization plant through this demonstration project on this area are implemented. In this paper, the activities for the approach on the commercialization for the oxyfuel combustion are mainly introduced and the current situation of Callide Oxyfuel Project is also outlined.

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Space Solar Power Systems (SSPS) is a promising concept for the large-scale clean energy system in the future. JAXA (Japan Aerospace Exploration Agency) has been making scientific research for the SSPS technologies and associated environmental issues. Microwave power transmission experiment on ground is planned to demonstrate the beaming technology from the orbit to the ground. In the experiment, the microwave beam at kW class is transmitted precisely to the rectenna target 100 m apart from the transmitter. We also plan a laser power transmission experiment using a kW class laser in a range of 500 m. In addition to these demonstration experiments on ground, we are investigating the SSPS demonstration experiment in orbit, which is aimed at verifying the microwave beaming technology in 500 km range and finding the upper limit of microwave power density through the ionosphere.

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Temperature characteristics is considered to be one of the most important characters affecting solar cell performance, especially those operating under concentrated solar radiation. After expatiation on the temperature characteristics of PV system, the choice basis and standard of concentration photovoltaic system is introduced. The particular temperature characteristics of concentration photovoltaic system which is different from normal PV system are analyzed. Nonuniformly temperature distribution's influence on PV system's electrical characteristics, which is caused by nonuniformly concentrated solar radiation, is discussed. The influence of thermal circle on thermal stress and the system's performance stability, in concentration PV system, are made an analysis. The result indicates that it is very important to consider the temperature characteristics as the inherent characters in the PV system. Cooling of photovoltaic cells is considered as one of the main concerns when designing concentration photovoltaic systems. In this paper, different ways of using system's thermal energy, and the major methods and work features for concentrated solar cells cooling system in the domestic and abroad are summarized, in order to provide the foundation of improving the efficiency of the concentrated photovoltaic systems.

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Nowadays increasing interest is toward the economic high temperature latent heat storage system (HTLHS) with a melting temperature of 100-300℃ as it is a key issue for the successful application of solar energy in the solar power plants using direct steam technology to generate process steam. Our research focuses on the performance of high temperature phase change storage for solar power generation using direct steam generation (DSG) technology in parabolic trough plants. Nitrate/nitrite salts and eutectic mixtures are the most promising PCMs considered for application in the HTLHS due to economic aspects, but the low thermal conductivities of salts affects significantly the performance of the storage system. Here by integrating foils into the PCM was put forward to overcome the low heat of transfer rates in HTLHS. Based on numerical analysis, detailed temperature and phase fields were obtained to account for the performance enhancement during the discharging process.

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Utilization of solar energy is essential to reduce consumption of fuels and emission of carbon dioxide. Two common ways are photovoltaic and photo-thermal conversions. Solar cells and a thermal collector can be combined into one system to form a photovoltaic-thermal (PV/T) system. The hybrid PV/T systems using amorphous-silicon (a-Si) cells might have a promising future due to its low initial cost. The objective of this paper is to provide a thermal analysis of this kind of hybrid PV/T system. Both the first-law analysis and the second-law analysis are applied for the hybrid system. The influence of a covering glass on the performance is emphasized. Effects of solar radiation, flow rate of the working fluid and wind speed are analyzed. Effects of the glass transmittance and the electrical efficiency of a-Si cells at the standard test temperature are also discussed. This work is important to the design of a hybrid PV/T system.

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This study addresses a tracking mechanism and control algorithm for driving the panel of photovoltaic generation system, in order to enhance the efficiency of power generation. Firstly, we propose the optimal driving pattern for one-axis tracking mechanism, which improves the efficiency about 5%. Our analysis on the geometric relation between the panel and the sun reveals that the optimal driving pattern is "S" curve which is different from the constant angular velocity, and the optimal pattern depends on the season. Secondly, we propose a novel mechanism for avoiding the shade on the neighbor panels. The proposed mechanism adds the rotational motion and translational motion by simple mechanism. The proposed mechanisms reduce the space required for installation without degrading the efficiency, and reduce the amount of initial investment.

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Authors have been developing a pure mechanical wave power generation system. The principle of the system is the application of the gyroscopic moment produced by the rotation of large flywheels and the swing of a float excited by wave motion. This paper presents the principle of the system, the developing process of prototype systems and their test results. It was confirmed that the system has higher efficiency than conventional OWC (oscillating water colum) wave power generation systems and sufficient reliability for actual application. The system will be applicable for distributed electric source for small island and ports.

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The objective of this study is to propose a new radial flow turbine for wave energy conversion and to clarify its performance by model testing. The proposed radial turbine has a rotor blade row for uni-directional airflow and two guide vane rows. The guide vane rows are named `floating nozzle' in the study. The guide vane rows slide in an axial direction and work as nozzle in the turbine alternately for bi-directional airflow, so as to rectify bi-directional airflow and to make uni-directional airflow. The rotor with a diameter of 500mm has been manufactured and investigated experimentally under steady flow condition which is generated by a wind tunnel using a piston/cylinder system with a diameter of 1.4m. As a result, it has been found that the peak efficiency of the proposed turbine is approximately 57% and the rotational speed of this turbine is considerably lower than that of Wells turbine.

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Power output fluctuation of 2 MW-wind turbine-generator systems, which apply fixed speed operation and variable speed operation separately, is analyzed through numerical simulation carried out by using an observed field wind data. The fixed speed operation has two levels of operating rotational speeds in response to the wind speed. The variable speed operation has two operation modes: a constant tip speed ratio operation mode at low wind speeds and constant speed operation mode at high wind speeds. For any operation, the pitch angle is controlled to maintain rated electric power output at high wind speeds. The simulation result shows that the variable speed operation can reduce the power output fluctuations with both long and short periods as compared with the fixed speed operation due to rotational inertia of the rotor. Furthermore, it is revealed that the pitch angle control is effective to reduce the power output fluctuation with long periods for any operation.

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In flight, many birds increase their height by flapping their wings. When it flaps the whole wing moves flexibly. This movement produces a difference in air resistance: the air is caught when the wing is moved in a downward direction and released when the wing is moved upward. We applied this mechanism to the wing of a wind turbine. This paper describes the result of a wind tunnel test on the CFRP Feather model which is the fifth model and uses a thin narrow plate of Carbon Fiber Reinforced Plastics (CFRP) instead of stainless steel. The power coefficient of the model is less than that of the fourth model. The possibility of vibration being one of the causes of the performance deterioration is shown. However, it is clarified that the output increases when the clearance of the middle wing is closed. Also, the middle wing which is near the rotational shaft greatly contributes to the output.

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One of the problems in green power generation is low density of energy and its temporal randomness. In this paper we analyze the properties and efficiency of a globally coupled multi-vibration system, which can accumulate the spatially spread energy into one special oscillator by using Grover wave algorithm. We have analyzed the mechanism of the present system that can only accumulate spatial coherent vibration energy by using Deutsch-Jozsa algorithm. Moreover, ideal efficiency of power generation can be evaluated from rotational properties of vibro-impact phenomena in Bloch sphere. Although the efficiency of the system depends on the number of small oscillators and the energy ratio between small oscillators, it achieves 50% under the optimal condition. Since the present system can accumulate temporally random but spatially coherent energy into a power generator, it can be one of unique methods for the green energy technology.

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Biomass is a significant renewable energy source. The conversion of woody biomass into a combustible gas provides the opportunity to enhance the efficiency of biomass-based power systems, and allows solid fuels to be used in high-efficiency power generation processes. This paper discusses the energy efficient utilization of biomass by turbo machines under unpressurized conditions, working with the inverted Brayton cycle in which turbine expansion, cooling by heat exchanger and draft by compressor are made in an open cycle mode. We call this an "atmospheric pressure turbine (APT)". Thermodynamic analysis has shown that an electric efficiency up to 25%(HHV) and a total energy efficiency of more than 80% (HHV) are expected for combined heat and power applications even at small plant capacities (〜40 kW)

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The paper deals with an experimental investigation on effects of percent excess airs (EA = 15%, 30%, 45%, 60%, and 75%) on axial/radial temperature distributions, gas emissions and combustion efficiency in a fluidized bed combustor (FBC) with wavy surfaces using rice husk as the fuels. The combustion chamber shape is cylindrical with 200 mm in diameter (D) and 2400 mm in height (H). The top part of the chamber is designed and constructed to be wavy surface walls. In constructing the wavy surface bed at the top chamber, five modules of converging-diverging nozzles are inserted into the bed at which each module has a throat diameter of 100 mm and height of 200 mm. In the experiments, the axial/radial temperature distributions inside the combustor are measured for each percent excess air used while the feeding rate of rice husk is kept constant at 95 kg/hr. From experimental results, the emissions of flue gases are found to be CO = 308 ppm and NO = 298 ppm, at EA = 75%. At all percent excess airs (EA) the axial/radial temperature distributions in the chamber are nearly uniform.

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We are involved in a development of small-scale gasification and power generation system in which biomass can be converted into energy with high efficiency. Our system has characteristics on gasification part and power generation part. Our gasification process consists of two parts: pyrolysis part (rotary kiln) and char gasification part (downdraft gasifier) in order to handle a relatively wide range of feed material shapes and to produce gas with little amount of tar. Meanwhile, in our power generation part, we tried to apply a mass-manufactured automobile engine with our own control system and to secure high generation efficiency even though the calorie of the produced gas generated by biomass gasification is low and variable. We performed fundamental experiments of the above-mentioned two parts and pilot tests with gasification and power generation system (50 kW electricity output). This report provides a summary of fundamental experiments and progress of gasification and power generation tests.

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Micro scale gasifier of biomass, which are refuse derived fuel and wood pellets, using the superheated steam has been developed and the feasibility of the generation pyrolysis gas as a fuel for micro co-generation was verified. The thermal cracking experiments were conducted at the superheated steam temperature from 500 to 700 degree C. The quantitative analysis of pyrolysis gases were carried out and residue amounts of char and tar were determined. Moisture and tar in the pyrolysis gas were removed by a cooling device which was kept at 0 degree C. The calorific values of the pyrolysis gases were about 14 to 19 MJ/Nm^3, and were 1/3 to 1/2 than that of town gas(13A). Then, the refined gas was supplied to a micro gas engine of 1 kW output as a fuel. The experiments were conducted repeatedly by changing the mixture ratio of pyrolysis gas and town gas. As a result, it turned out that the mixture of 13% of pyrolysis gas to the town gas is possible under keeping constant power output.

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Unused woody biomass in Japan is currently available from various sources such as wood chips from sawmills, material left in woodland areas, pruned roadside trees, and builder's waste. Of these, wood chips from sawmills and material left in woodland areas are particularly plentiful, but since they are thinly distributed over extensive mountainous regions, these sources are not utilized effectively. This study is aimed at developing a small-scale (100kW〜1MW Class) distributed power generation system that can make effective use of the unused biomass in these mountainous regions more efficiently and economically than before by combining a fluidized bed gasification furnace with a gas turbine. In this paper, we report on the results of bench tests performed with a 20 kW class power generation and on a 150 kW prototype facility that is currently undergoing field test.

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To reduce the exhaustion of carbon dioxide in power plants, the operating technology for co-firing of woody biomass and coal at existing coal-fueled power plants has come to attract attention. The pretreatment of semi-carbonization and comminution before transportation can be effective in reducing the energy consumption due to transportation of biomass. The main purpose of the study is to investigate the effect of semi-carbonization on comminution energy and assessment of transport property of woody biomass. The results obtained are as follows. Empirical correlations of work index in Bond's Law are presented for both woody and semi-carbonization regions. The comminution energy can be estimated by the present empirical correlations within an accuracy of ±30 percent. From the result of analysis of energy consumptions, it is found that the total energy loss due to pyrolysis, transportation and comminution is the minimum at a mass yield condition of 0.6 for the same transport distance.

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Experimental study for clarifying the effect of combustion mechanism on reforming producer gas was conducted. The inversed diffusion flame was formed in the actual gas reformer by partial combustion of producer gas. Direct observation and laser diagnosis were applied to the inverse diffusion flame. Experimental parameters are steam concentration in supplied model producer gas (X_<steam>) corresponding to moisture content of wood. The main results are as follows. In the condition of 20 % concentration of oxygen, flames at nozzle and lifted flames were formed in the same supply condition by hysteresis. When the flames at nozzle were formed, the exergy yield was increased with the increase of X_<steam> because soot formation was suppressed and steam reforming of model tar could proceed. In contrast, when the lifted flames were formed, the exergy yield was decreased with the increase of X_<steam> because of formation of SOF (soluble organic fraction).

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Gasification power generation plant has significant potential for highly efficient utilization of biomass and refuse derived materials. This work evaluates the performance of the dry gas cleaning system for the power generation plant and to examine its feasibility in commercial scale. Sorbents for impurity removal was prepared as copper based mercury sorbent, glass fiber reinforced halide sorbent and zinc oxide sulfur sorbent. Performance evaluation in the demonstration plant showed sufficient performance for various impurities. Power generation test with the molten carbonate fuel cell (MCFC) was also successful in accomplishing stable power generation with the MCFC. The commercial scale plant of dry and wet system was designed and compared, which showed large advantage of the dry system. These results confirmed that the dry gas cleaning system is sufficiently feasible to establish the biomass gasification based power generation system.

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Driven by a growing awareness of global warming which prompts calls for provision of urgent countermeasures world-wide, energy saving technologies are developing in various fields and industries. The production industry is no exception where steam plays diversified roles such as heating, drying, condensation and pasteurization in the various production processes. However, some amount of steam energy is left unused in these areas. It may not be a well-recognized issue that technologies need to be developed to effectively utilize such unused steam energy. Kobe Steel, Ltd. has developed a "screw type steam-powered compact electric power generator Steam Star" that makes use of unused steam energy while promoting further energy saving and reducing generation of carbon dioxide. The Steam Star is capable of not only generating electric power at a high efficiency even with a small amount of steam but also generating at the same time necessary steam at a reduced pressure through its pressure reduction function. This paper discusses the new technologies associated with the "screw type steam-powered compact electric power generator Steam Star", compares it with conventional turbine-driven electric power generators and introduces some case examples of its use.

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China has already put forward one of the important targets for saving energy and reducing emissions in the iron and steel industry, then the efficient recovery and the full use of the waste heat can become the breakthrough of the further energy-saving iron and steel production. According to the difference between characteristics and quality of the waste heat in the Sintering process, the paper firstly puts forward the technical schemes which include the integrate recovery and steps utilize of the sintering hot gas and waste heat to power generation, then studies the foundation which involved the gas-soild heat exchange and the steam parameters optimize and so on, and also develops the key technology. The results provide a theoretical basis for the improvement of the waste heat power generation device, and also give technical assurance for saving energy and reducing emissions in the iron and steel industry.

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In this paper, a detailed thermodynamic analysis of the pure low-temperature waste heat recovery generation system is presented. The parameters affecting the system performance are compared to obtain the most significant ones; furthermore, parameter values are optimized for the largest power generating capability of the system. It is found that the most important parameters are inlet flue gas temperature, steam pressure and the pinch point temperature difference. There is an optimal superheated steam pressure value for giving the maximum generation power per unit flue gas. With the increase of inlet flue gas temperature, the generating power increases and the optimized steam pressure rises as well. However, with increase in pinch point temperature difference, the generating power decreases and the optimized steam pressure decreases as well. The theoretical calculation provides a theoretical basis for the parameters optimization in the design of the pure low-temperature waste heat recovery generation system.

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Two broiler chicken industries have been growing in the two districts in Japan. One is South Kyusyu and the other is Northern Japan. South Kyusyu district has been operating some chicken waste power generations with successful operation result, but not experience in Northern Japan. Chicken waste is to subject on environment issue such as foul smell and polluted water, and expected to utilize it as biomass energy. In this circumstance, a feasibility study in this district was conducted to show how it was feasible or not using IRR (Internal Rate of Return) method. This feasibility study shows us that less than 80,000 ton per year of chicken waste (mixture of broiler litter and lying egg litter) is high potential commercialization of the power generation system under the some of the conditions. Several findings are reported in this paper on cost of the reasonable treatment fee, and recent market trend of phosphorus fertilizer which is generated from ash of chicken waste as fuel of the plant.

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CO_2 emissions, which are the cause of global warming, are increasing in the residential sector while staying constant in the industrial sector in Japan. One promising solution to reduce CO_2 emissions is installing high efficiency devices that supply heat and/or power: photo voltaics, a heat pump water heater and a co-generation system. Optimizing the devices require changing an existing energy system into innovative energy systems, which is a microgrid. The objective of our research was to reduce CO_2 emissions with microgrid. We used a simulation to determine the reduction with the microgrid that consists of three residences and with the virtual-MG that explored the potential of the MG We observed that the virtual microgrid reduced while the MG of this research didn't reduce. We concluded that the microgrid has the potential reduction while reaching microgrid's full potential will require making the capacity or the running time of the devices small.

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