In the 21st century, the reduction of the fossil fuel consumption is strongly requested from the viewpoints of both the reduction of CO2 gas to prevent the global warming and the energy security. Under these circumstances, the usage of the cogeneration systems is growing and recently, small scale cogeneration systems have been put on market. As small scale cogeneration systems, there are the reciprocating engine based ones, the micro-gasturbine engine based ones and the fuel cell based ones. In this paper, the present and the future of the cogeneration systems using micro-gasturbines, which are expected to increase due to the high efficiency, the compactness and the environmental friendliness, are discussed.
NTT Facilities has tied up with Bowman Power Systems for marketing of Micro-gas-turbine CGS in Japan. We have tested Micro-gas-turbine CGS "TG80CG" in order to confirm the performance. This article describes some basic characteristics such as starting sequence, heat balance, emission and characteristics as sudden load change. In addition, we introduce our plan about remote monitoring and plant management to extend the maintenance frequency. We are planning to expand the maintenance frequency for temporal transitional management data that we get by remote monitoring system.
Construction of Co-generation system with Micro-gasterbine will be necessary to spread widely in the distributed power generation field. Utilization of exhaust gas by co-generation will contribute to reduction of total energy consumption and will be supposed to decrease the discharge of CO2 which is a cause of green house effects, compared to traditional commercial electric power generation system. In this paper features of developed hot water supply system combined with micro-terbine TA-80 engine are stated and single-double effect absorption chiiler/heater applied for air conditioning also. Co-generation system with developed water boiler package and chiller/heater with high energy utilization ratio is found to decrease the discharge of CO2,compared to traditional energy source system which consists of commercial electric power and city gas.
From the viewpoint of the cascading utilization of thermal energy, we focused on power recovery by Rankine cycle driven by exhaust gas coming from the micro-gas turbine. Removing chlorine atomic from conventional fluorocarbons, named by CFC and HCFC, brings higher temperature of the expander inlet up to about 200 degree-C, so the higher performance of Rankine cycle is expected. In this study, we have discussed the working fluids for Rankine cycle, the performance of main elements such as refrigerant pump and evaporator, and the performance of cycle. Experimental data analysis shows (1) The efficiency of scroll type expander is about 60%, (2) Cycle efficiency with regenerator is half as much again as that without regenerator, and (3) Maximum of cycle efficiency is about 9%.
Micro gas turbine co-generation system is expected as one of an ecological distributed energy system. Here, I introduce applications of micro gas turbine. i. e. micro gas turbine cogeneration system (MCGS), MCGS with U. P. S., hybrid MCGS combined with PV and wind power, desiccant-based air conditioning system, MCGS using biomass energy, and so on.
Two-dimensional conjugate conduction/convection numerical simulations were carried out for flow and thermal fields in the minimal unit model of a counter flow type corrugated plate heat exchanger to study the effects of plate thermal resistance on its thermal characteristics. Computations were carried out for two plate geometries having different plate thickness in the Reynolds number range of 100<Re<400. It was found that the case of thicker corrugated plate can have the better heat transfer performance compared with the thinner one, taking a higher value of the temperature effectiveness for unit length at a fixed pumping power. This is ascribed to the combined effects of change in plate shape due to the different plate thickness and the decrease of thermal resistance inside the solid part in tangential direction of the plate surface.
Cogeneration systems (CGS) are penetrating power generation markets because of their potential of higher energy utilization efficiency with waste heat recovery process. Cost saving merit helps the promotion of CGS; however, this does not always lead to energy saving. We investigate the energy cost minimum operation of CGS using our performance test results of a micro gas turbine (μGT) as well as typical demand patterns of offices and hotels. We also calculate the fuel consumption associated with proposed modes of operation. It is found that we can achieve considerable cost saving (cost saving rate : office 37%, hotel 44%), but the fuel consumptions are increased at the same time. However, when the power generation efficiency of μGT is improved to 35%, we can achieve energy saving with the energy cost minimum operation.
The relationships between optimal capacities and installed number of microturbine cogeneration units and maximum energy demands are surveyed based on an optimization approach. Equipment capacities, installed number of the microturbine cogeneration units and maximum contract demands of utilities such as electricity and natural gas are determined so as to minimize the annual total cost in consideration of operational strategies subject to satisfaction of energy demand requirements. Numerical studies are carried out on microturbine cogeneration systems installed in hotels and office buildings by changing the maximum energy demand. Through the studies, the relationships between the optimal capacities and the installed number of the microturbine cogeneration units and the maximum energy demands are clarified, and it is found that plural microturbine cogeneration units may be installed from an economic viewpoint.
Recently, the distributed energy system has spread quickly for reasons of earth environment preservation, CO_2 discharge reduction, and effective use of energy. Under such a situation, the co-generation system (which supplies electricity and steam), and the variable heat and power ratio type co-generation system (which combined with steamy injected gas turbine), and the combined cycle plant system (which combined with steam turbine as bottoming cycle system) are expected. This paper describes a development of combined cycle plant system with Kawasaki L20A gas turbine, which is ISO base load rated at 25.35MW gloss plant output and 48.8% thermal efficiency (LHV).
This paper describes a comparison of steam injected gas turbine system with gas turbine combined system in co-generation. The comparison is based on the actual gas turbine KAWASAKI M7A-02 data and specifications. A brief financial portrait of the system is also shown. The result shows that (1) a suitable system which gives minimum years for payback of equity is determined in terms of the site heat demand and electric demand (2) steam injected gas turbine co-generation system gives shorter years for payback of equity when the ratio of heat demand/electric demand is greater than 0.3 (3) CCPP co-generation system gives shorter years for payback of equity when the ratio of heat demand/electric demand is 0∿0.3.
This paper describes a development of a hybrid ammonia/water refrigeration cycle to make cold energy of-20C by gas engine exhaust heat. The refrigerator incorporates a turbocharger to transport ammonia vapor from the evaporator to the absorber of an absorption cycle, which makes the refrigeration possible by jacket water exhaust heat of relatively low temperature. The newly invented hybrid system proposed here can use both exhaust gas and jacket water effectively. The turbine, of which rotation is 130,000 rpm, is driven by ammonia/water steam vaporized by gas engine exhaust heat. As it uses ammonia gas bearing free from lubricating oil, the system can be made hermetic. In some operating conditions, the refrigeration capacity is more than twice as large as ordinary system driven by only the high temperature portion of the exhaust gas. The development was started as a three year project, financially assisted by NEDO.
Economic, energy-saving and environmental protection feasibilities of solid oxide fuel cell (SOFC) and SOFC/microturbine (MT) hybrid cogeneration systems are investigated based on a multiobjective optimization approach. Equipment capacities and maximum contract demands of utilities such as electricity and natural gas are determined so as to minimize the annual total cost, the annual primary energy consumption and the annual CO_2 emission in consideration of operational strategies subject to satisfaction of all the energy demand requirments. The ε-constraint method is adopted as a solution one for the above multiobjective optimization problem. Numerical studies are carried out on SOFC and SOFC/MT hybrid cogeneration systems installed in a hotel by changing the capital unit costs of the SOFC and SOFC/MT cogeneration units. Through the studies, the trade-off relationships between the economic. energy-saving and environmental protection properties are clarified, and it is found that the SOFC/MT hybrid system is excellent from viewpoints of energy-saving and environmental protection properties.
Design-point and part-load characteristics of a gas turbine-solid oxide fuel cell hybrid micro generation system, of which total power output is 30kW, are investigated for its prospective use in the small distributed energy systems. A cycle analysis of the hybrid system has been performed to obtain general strategies of highly efficient operation and control. The method of analysis has been verified by comparison with previous results, of which power output was assumed in the range from 259 to 519kW. Them, the part-load performance of the 30kW system has been evaluated. Two typical operation modes, i. e., constant and variable rotation speed gas turbine operation, are considered. It is found that the variable speed mode is more advantageous to avoid performance degradation under part-load conditions. Operating under this mode, despite 10% adiabatic efficiency drop in the gas turbine components, the generation efficiency can be maintained over 60% (LHV) in the power output range from 40 to 100%. The turbine exhaust temperature, however, is increased with decreasing the power output under the variable speed mode with the constant SOFC operating temperature, so that the thermal durability of recuperator material becomes critical issue. Finally, the effect of compressor/turbine operating lines on the system performance is evaluated.
In December of 1994,the "New Energy Introduction Principle" was established as the national guidelines for the effective promotion of the new energy introduction where the waste-fired power generation was referred to as one of the new energy sources. RDF is effective for the waste to energy system in cooperate with small and medium local government. Because RDF can improve handing efficiency in transportation and storage by densified and protection spoilage. 4.2t/h steam generation capacity demonstration thermal power plant using RDF has been operated from Oct. 1997 until today more than 16,7000hrs at Wakamatsu Coal Utilization Research Center, Electric Power Development Co., LTD, supported by the METI. This paper is described about outline of the demonstration test results.
In oxygen-blown IGCC, the gasification efficiency decreases according as oxygen concentration in the gasifying agent (oxidant) decreases. However, there is a possibility that the improvement of the entire plant efficiency and the cost reduction can be achieved because the producing-power of oxygen can be decreased on the other hand. Therefore a quantitative grasp of the influence that the oxygen concentration exerts on the gasification efficiency is expected. The gasification test regarding the oxygen concentration change was carried out using the bench-scale gasification facility in this study. An (Orimulsion)^<TM> was used for the gasification test. As a result, the influence that the oxygen concentration exerts on the gasification efficiency (e. g. the cold gas efficiency, carbon conversion efficiency and the others) was obtained. The thermal efficiency of a simple IGCC system was calculated based on the relationship between the oxygen concentration and the gasification efficiency. In this study, the oxygen ratio to achieve high efficiency at each of concentrations was clarified
This paper shows a new combustion system to utilize heavy oils such as asphalt or vacuum residue directly for boiler fuel suppressing the NO_x emission. The concept of this system is derived from the CPC (Coal Partial Combustor) technology as a coal gasification combustor. Through the test carried out using the specially modified test furnace, it is proved that this technology is available to keep NO_x emission below 100ppm. Three industrial boilers were designed and constructed based on this concept. Through test operations for each boiler, NOx emission levels were confirmed to keep below 100pm.
We studied an entrained-flow gasification process which efficiently converts waste plastics to energy at a high energy recovery rate. Waste plastics, after being shredded to <10mm, were fed into an entrained-flow gasifier with air, oxygen, steam and CO_2 gas. In the gasifier, organic substances were pyrolyzed, partially combusted, and then converted into synthetic gas (CO, H_2) at a high temperature (over 1,600K). Other inert substances in the wastes such as ashes and metals were melted into slag and condensed on bag filters. The bag filters and a water scrubber removed inpurities such as dust, heavy metals, and hydrogen halides from the product gases. Solid hydrocarbons, which include char and soot, were removed at a hot cyclone and on the bag filters
An innovative small-scale gasification system for solid wastes is proposed which is known as STAR-MEET system. In this system, a fixed-bed pyrolyzer combined with a high temperature reformer using high temperature steam/air mixture is employed. From the experimental results using rubber chips as a fuel, it has been demonstrated that injection of high temperature steam/air mixture into the pyrolysis gas effectively decomposes tar and soot components in the pyrolysis gas into CO and H_2,and almost dust and tar free clean reformed gas can be generated. The STAR-MEET system requires high temperature steam/air generator, and a 900℃ class metallic type compact heat exchanger has been successfully developed. Finally, power generation experiments using a complete STAR-MEET plant has been successfully done. These results demonstrates small-scale gasification and power generation system using solid wastes is quite feasible.
MEET (Multi-staged Enthalpy Extraction Technology) system is a new coal/wastes-fired power generation system. In order to realize MEET system, the demonstration plant of commercial scale, MEET II, was completed. The capacity of MEET II is 2 t/day of coal or 4 t/day of RDF. There were no such small-scale plants which can utilize energy from solid fuel. MEET II consists of pebble bed slagging-gasifier, high-temperature air generator and high temperature air combustion boiler. Gasification by high-temperature air results in higher calorific value of syngas. Cleaned-up syngas is used as a fuel of boiler, and for preheating air to high temperature. Tests at MEET II were carried out step by step. In order to obtain higher gasification efficiency, we modified some parts of the gasifier and then obtained targeted high-calorific syngas on pulverized coal test. Temperature at the pebble bed was kept above the ash fusion temperature and slag was extracted smoothly.
This paper describes the operating condition of 1.5MW gas engine system with pyrolysis gas produced in the waste gasification plant. This system started since Octorber 2001 at Kawasaki-Steel chiba works. The results shows the following four conclusions; (1) Gas engine can operate continuously with pyrolsis gas of which LHV is between approximately 1500 and 2200kcal/m^3_N, enen when the fluctuation of LHV is approximately 3%/30s. (2) Electrical efficiency is 37% at 100% load and 33% at 50% load respectively. (3) The concentration of dioxins in the exhaust gas was approximately 0.001ng-TEQ/m^3_N. (4) The concentration of NO_x in the exhaust gas is less than 100ppm (O_2=0%) without SCR.
Deep understanding of the various phenomena in a coal gasifier can be very useful in order to optimize performance and operate the gasifier. A numerical simulation technology which can achieve reasonable design of gasifier is effective. The object of this study is to develop an evaluation tool for a design and performance of the gasifier with numerical simulation technique. In this paper, we suggest numerical simulation models on the coal gasifier and examine the current model on 2t/d bench scale coal gasifier of CRIEPI. Results in a relationship between the gasifier performance and operating condition (air ratio) agree with the experimental results of 2t/d gasifier. Calculation on Nakoso 200t/d pilot scale gasifier is also carried out to assess the effect of burner conditions. It was found that increasing of the secondary air velocity of the burner is more effective than increasing of the virtual diameter ratio on both ash captured efficiency in combustor and carbon conversion efficiency at combustor exit.
The nine regional power companies of Japan, EPDC (Electric Power Development Company) and CRIEPI (Central Research Institute of Electric Power Industry) to conduct the 250MW Air-blown IGCC Demonstration Project have established Clean Coal Power R & D Co. Ltd. (CCP) on June 15,2001. Plant construction will start in 2004 followed by operation tests through 2009. This report presents status of the project and outline of the demonstration plant.
The purpose of the EAGLE (coal Energy Application for Gas, Liquid and Electricity) Project is to develop the technology to produce coal gas for fuel cells. The EAGLE system applies an oxygen blown, entrained flow type gasifier, in which the spiral flow is formed. Oxygen is produced with an ASU (Air Separation Unit) and supplied to the gasifier. The produced coal gas is cooled through the radiant section of the gasifier and a syngas cooler. Impurities in raw syngas are removed with water scrubbers, a COS converter and an MDEA (Methyl Di-Ethanol Amine) absorber. Part of the syngas is further desulfurized with iron oxides for fuel cells. The EAGLE Project is subsidized by METI (Ministry of Economy, Trade and Industry) and NEDO (New Energy and Industrial Technology Development Organization). In 1995,a feasibility study of IGFC (Integrated coal Gasification Fuel Cell combined cycle) systems was conducted. In 1996 and 1997,a basic design and a detailed design were carried out, respectively. Its construction work was started at Wakamatsu Operations & General Management Office in August 1998. A pilot plant test has continuing since July 2001.
This study is concerned with the production of ashless coal (called as Hypercoal, HPC) by the extraction of pure coal effective for combustion from raw coal and the construction of high efficient compound cycle electric power generation system by injecting the HPC directly to gas turbine in order to reduce CO_2 emissions. The HPC with 200ppm of ash content and 0.5ppm of alkali (Na+K) content was produced by removing ash with 1-Methyl naphthalene (1MN) and alkali with inorganic ion-exchange material. The burnout time of HPC with 10μm diameter was estimated as below 0.1 seconds by the simulation of gas turbine combustion. As a result of LCA on the CO_2 load of this system, namely HPC direct combustion gas turbine power generation system with 48% of net thermal efficiency, 20% of CO_2 emissions reduction can be expected comparing with the conventional PCF system.
Research subcommittee on steam turbine technology responding to the circumstances at the power generating industry in the (21)^st century worked three years from November, 1998,to investigate the recent steam turbine technology and to discuss the subjects responding to the circumstances in the power generating industry hereafter. This paper introduces the outline of the activities of this subcommittee and necessary action discussed to respond to the subjects required from the power generating industry hereafter.
Toshiba has been developing and applying new technology to improve steam turbine plant efficiency in response to issues of natural resources and global environment. This paper describes history and the latest technology of steam turbine with high temperature and pressure steam condition.
Highly loaded nozzle blades of steam turbines are developed. The pitch-chord ratio of these nozzles increases by 14% compared to one of conventional nozzles. And the increase of the stage efficiency is about 0.35% at the design point. This reason is that the strong adverse pressure gradient along blade suction surface is avoided in spite of the increase of blade loading, because the blade loading is equally distributed to the whole blade and the curvature of suction surface are optimized. In the first step of development, the nozzles are designed by the aid of computational fluid dynamics technique. In the next step, the aerofoil performances are tested by the use of linear cascade test facility. In the final step, the increases of stage efficiency are assured by the air turbine test results.
We have been developing new long blades with high efficiency and reliability using the advanced design and analysis techniques. Reviewed performance design has been achieved by adopting the best suited transonic profile, taking account of 3D flow and steam effects. High reliability design has been also achieved by adopting an integrally formed cover and a mid-span connecting member. This structure is called as a CCB (Continuous Cover Blade) structure. This paper describes the modern design and analysis techniques, and presents the characteristics of CCB structure. The resonant response analysis and CFD analysis are performed for conventional and CCB structures. The results are compared and discussed.
A low pressure end blade for thermal power plant is one of the most important elements in a steam turbine design to determine the performance, the dimension and the number of casings of the turbine. Applying the state of the art technology for aerodynamic design and mechanical design, Mitsubishi Heavy Industries (MHI) has been conducting a developing program of new advanced low pressure end blades with ISB (ISB : Integral Shroud Blade) construction in order to enhance steam turbine efficiency and reliability. A series of these low pressure end blades has been completed for 50Hz and 60Hz unit application inclusive of 3600rpm 45 inch Titanium blade, and 1500/1800rpm 54 inch steel blade. And those blades have good operation experience more than 10 years. This paper reports on the up-to-date design technology applied for new advanced low pressure end blades and on the verification tests to ensure high efficiency and reliability of the blade.
Design drawings must reflect design information accurately in the optimum design of compact, reliable steam turbine casings. The numerical analysis code is effective in such optimum design, and design techniques are improved by implementing the latest technology and including user subroutines. CFD was developed to measure temperature accurately and inelastic FEM for calculating bolt stress relaxation precisely. These two techniques are used to design high to medium pressure casings.
Rotational effect on a labyrinth seal was examined experimentally using a scale test apparatus. Numerical study was also done for understanding seal phenomena for that model. The experiment was performed under the condition of the labyrinth clearance equals to 4,8,12[mm], the inlet pressure (P_in) at test section as 101.4-238.4[kPa] and rotational speed of the model as 0-4000[rpm]. It was observed that discharge coefficient decreasing linearly as increasing the pressure ratio (P_in/P_out' P_out : atmospheric pressure) at O[rpm] for almost whole pressure region studied. On the other hand discharge coefficient decreasing rapidly as increasing the pressure ratio at high rotational speed conditions (2000[rpm] and 4000[rpm]). Numerical simulation clarified that the rotational effect obviously appears in the flow pattern in the clearance region of the labyrinth seal as the difference of both the position and the scale of the vortex formed in that region.
This paper presents the analysis of a large turbine-generator system with foundation effects. Approximate modal analysis is used to analyze the complicated rotor-foundation system. The system is decomposed into 1) rotors including gyroscopic effects, 2) bearings having nonsymmeric and speed dependent properties, and 3) flexible support structure. The dynamic characteristics of the bearing and support structure have significant effects on the rotor dynamics. The rotors are identified by finite element method. The stiffness and damping of the bearing are analyzed by the thermo-hydrodynamic lubrication analysis considering the deformation of the pads and bearings. The stiffness of the bearing spherical seat is analyzed by finite element method and verified by the scale test. The foundation properties are identified by finite element method and the shaker test. Typical rotor is used as an example to illustrate the application of this analysis. This method enables an efficient approach to predict the system vibration properties.
The damage example is increasing which it is difficult part to check directly with the increase in worn thermal power station. The damage on a steam-turbine low-pressure rotor blade stud section is a typical example. It is possible to establish predict evaluation by the external factor or the situational factor in case of low-pressure rotor. According to the statistically evaluation from actual result external cause data, and physical cause analysis, we established the predict evaluation of the low-pressure rotor damage situation, "the predict evaluation approach of the degree of low-pressure rotor corrosion-fatigue damage risk".
To seek for a promising concept of a fast reactor plant, Japan Nuclear Cycle Development Institute (JNC) and the electric utilities conducted conceptual design study on various types of plant concepts and compared these concepts based on technical feasibility and economical perspective. The construction cost goal is set at \200,000/kWe. The study was finished at the first stage for two years. Now it goes on at the second stage.
In Phase I of the "Feasibility Study on Commercialized Fast Reactor Cycle Systems (F/S)", an advanced loop type reactor has been selected as a promising concept, which has a possibility to fulfill the economic goal of the F/S (construction cost : less than \200,000/kWe, etc.). In Phase II of the F/S, with reflecting the results of elemental experiments, a preliminary conceptual design of this plant will be preceded toward the selection for narrowing down candidate concepts at the end of Phase II.
To seek for a promising concept of a heavy liquid metal coolant (HLMC) fast reactor plant, Japan Nuclear Cycle Development Institute (JNC) and the electric utilities conducted conceptual design study on various types of plant concepts and compared these concepts based on technical feasibility and economical perspective. The Lead-Bismuth cooled complete natural circulation reactor concept may attain high safety level and construction cost goal (\200,000/kWe).
To seek for a promising concept of a inert gas coolant fast reactor plant (GCFR), Japan Nuclear Cycle Development Institute (JNC) and the electric utilities conducted conceptual design study on various types of plant concepts and compared these concepts based on technical feasibility and economical perspective. The Helium gas cooled reactor concept may attain high safety level and construction cost goal.
The 200kWe uranium-nitride fueled lithium cooled operator-free reactor RAPID-L has been demonstrated. The reactor has no control rod, but involves the following innovative reactivity control systems : Lithium Expansion Modules (LEM) for inherent reactivity feedback, Lithium Injection Modules (LIM) for inherent ultimate shutdown, and Lithium Release Modules (LRM) for automated reactor startup. All these systems adopt lithium-6 as a liquid poison instead of B_4C rods. In combination with LEMs, LIMs and LRMs, RAPID-L can be operated without operator. This is the first reactor concept ever established in the world. This reactor concept is also applicable to the terrestrial fast reactors.
Remote maintenance is an essential technology of the International Thermonuclear Experimental Reactor (ITER) since the in-vessel components such as blanket are scheduled to be replaced remotely. Major object of the development of the remote robot is to verify the feasibility of sensor based control for rail deployment and module replacement. This paper describe a new control scheme of sensor based control regarding the rail deployment and module replacement.
The first fabrication and heating tests of a large-scale Carbon-Fiber-reinforced Composite (CFC) monoblock divertor mock-up using the annular flow concept were performed to demonstrate its manufacturability and thermo-mechanical performance. This mock-up was based on the design of the vertical target of the International Thermonuclear Experimental Reactor (ITER) divertor adapted for the annular flow concept. The annular cooling tube consists of two concentric tubes; the outer tube made of CuCrZr and the inner stainless steel tube with a twisted external fin. critical Heat Flux (CHF) testing of the annular cooling tube and brazed joint between the CFC and CuCrZr were performed prior to the fabrication of the mock-up to examine fabrication process. High heat flux test on this mock-up was performed in an ion beam facility. The mock-up has successfully withstood 1000 thermal cycles of 20MW/m^2,for 15s, which is relevant to the transient heat load of the ITER divertor. No degradation of the thermal performance of the mock-up has been observed throughout the thermal cycle test. These results show that the vertical target using the annular flow concept is applicable to the ITER divertor design.
JAERI has undertaken the design study of an original concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements for earlier technology deployment. The GTHTR300 is expected to be an efficient and economically competitive reactor in 2010s due to newly proposed design features such as core design with two-year refueling interval, conventional steel material usage for a reactor pressure vessel, innovative plant flow scheme and horizontally installed gas turbine unit. This paper describes the original design features focusing on reactor core design, fuel design, in-core structure design and Reactor Pressure Vessel design. It also reported a preliminary cost evaluation proving that the capital cost is less than a target cost of 200 thousands Yen/kWe. Present study is entrusted from Ministry of Education, Culture, Sports, Science and Technology of Japan.