Combined Cycle Power Generation System Research Articles

Flue Gas Desulfurization at High Temperatures: A Review

The energy demand of the world, which increases in accordance with the rise in economic development, will have to be met by the prevalent energy sources, such as coal, new sources, as well as improvement of the efficiency of energy production technologies. However, the growth in energy production need not take place to the detriment of the environment, so that strict regulations on pollutant emissions have been imposed around the world. Combined cycle power generation systems are being advanced t oday, due to their higher thermal efficiency and superior environmental performance and economics, compared to conventional plants. Hot gas cleaning techniques to remove sulfur and other impurities in the flue gas streams offer the key advantages to such systems. This paper reviews briefly the Hot Gas Desulfurization (HGD) techniques and the processes' development and performance estimates, some test programs using HGD, and market potential and economic issues.

04/01503 Analysis of the environmental impact of a PFBC-CC (pressurized fluidized bed combustion combined cycle) system by using an exergy method: Zheng, P.-Y et al. Reneng Dongli Gongcheng, 2003, 18, (1), 74–77. (In Chinese)

By using an exergy method a model for the thermal analysis of system emissions and waste heat was set up. Starting from the concept of exergy the environmental impact of emissions is analyzed in general. Furthermore, the impact on environment of a PFBC-CC (pressurized fluidized bed combustion combined cycle) power generation system has also been analyzed. The results of the analysis indicate that the environmental impact of CO 2 emissions and waste heat of the system should not be ignored. The transfer of element S from SO 2 into CaSO 4 can drastically reduce the environmental impact of the system. To achieve a more comprehensive analysis of the environmental impact with the help of the exergy method, it is necessary to conduct a more thoroughgoing research on a reference environment model.

C306 The Development of Coal Energy Application for Gas, Liquid & Electricity EAGLE

It is clear that the IGFC system, which is composed of a fuel cell, gas turbine and steam turbine, the so-called triple combined cycle power generation system, has considerably higher efficiency when compared with a conventional coal-fired power plant according to this feasibility study. The EAGLE pilot plant operation has been conducted to develop a gasifier and establish a gas clean-up system for cells since July 2001.

Wave-PV Hybrid Generation System of the Offshore Floating Type Wave Power Device “Mighty Whale”

For converting renewable energy into electricity, it is not only important to raise energy conversion efficiency, but also to flat-and-smooth of generating electricity considering demand-and-supply balance and system cooperation. Although there are accumulation of electricity and a proposal of storing energy with a flywheel etc., as this measure, equipment different from power generation is needed, and it becomes the factor which raises cost.Generally, when it is fine, a wave is small, and when a wave is high, it is bad weather. For this reason, it is thought that photovoltaics and wave power generation can complement each other fault, and can perform flat-and-smoothization of the amount of power generation.This paper describes verification of the possibility of hybridizing of solar and wave energy and application to the system from an experiment of the combined cycle power generation system of the photovoltaics and wave power generation which were performed with the Offshore Wave Power Device “Mighty Whale”.

火力発電所中圧蒸気活用ＣＯ２回収ＮＯＸフリー・リパワリングシステムの特性と経済性評価

A CO2-capturing NOx-free H2O turbine power generation system is proposed in which middle pressure steam produced in a thermal power plant is utilized to increase generated power when demand for electricity is large. The proposed system can capture all the generated CO2 based on the oxygen combustion method and emits no NOx, so that it causes no urban and global environmental problems. A combined cycle power generation system with 200MW gas turbine power output is adopted as an example of a thermal power plant. It was assumed that 32 t/h of steam with 25kg/cm2 pressure produced at waste heat recovery boiler was utilized in the proposed system.It has been shown through simulation study that increase of power output by 11.8MW or 4.51% of the rated output is possible with no efficiency decrease. The amount of CO2 reduction is estimated to be 19600t/y.The unit cost of generated power is estimated to be 8.38yen/kWh, annual gross profit of the proposed system 271 million yen, depreciation year 4.87, and thus the proposed system is estimated to be economically feasible.

Numerical analysis of a flow passing through a ceramic candle filter on pulse jet cleaning

Ceramic filters are often utilized to collect dust particles under the very high temperature and high pressure conditions in flue gases for gas turbines or fuel cells in combined cycle power generation systems, and for their long-term use the dust cakes attached on the filter surface should be removed at adequate intervals. At present, the pulse jet-type dust cleaning method is considered to be the most useful. In this study, a numerical simulation is applied to a flow passing through a ceramic candle filter on the pulse jet cleaning, and the validity of it and the detailed flow behaviors are investigated by comparison with experiment. The results show that the present computation is valid in predicting the flow characteristics in the ceramic candle filters for arbitrary pulse jet and dust cake packing density conditions. Also, the dust-removal behaviors observed in the experiment can be well explained by using the time variation of pressure (static pressure) between the filter and dust cake.

Study on Extra Heavy Oil Gasification Reaction Process.

From the viewpoints of global environment and energy security, raising the thermal efficiency of a thermal power plant and the diversification of fuel are issues that must be resolved as soon as possible. As to resolving these two issues, it is very effective that extra heavy oil is used in a gas-steam combined cycle power generation system. Accordingly, in order to establish technology for supporting to rationally design and operate a gasifier using extra heavy oil, the Central Research Institute of Electric Power Industry (CRIEPI) targeted at clarifying significant phenomena in a gasifier, improving the accuracy of numerical analytical technique under development and verifying the technique. This report describes the major specifications of “Research Gasifier for Liquid Fuel” constructed in 1999 and the results of studies in respect to the reaction process in the gasifier based on OrimulsionTM (Trademark of BITOR) gasification tests in 2000.

石炭の加圧流動層燃焼技術

This article describes the present status of pressurized fluidized bed combustion (PFBC) technologies for coal. PFBC technology is commonly recognized as a future generation coal combustion technology and R&D has been done among advanced countries. PFBC technology offers a high efficiency and low emission combustion technology of coal by using a combined cycle power generation system. Wide variety of coal, lignite to anthracite, can be burned by PFBC technology, and coal energy can be converted to electricity with higher thermal efficiency. PFBC technology has recently entered the commercial stage. In Japan, three units have been under commercial operation. In other countries, some commercial units are under construction or operation. Their operability and performance are good enough to be a commercial plant. Especially, NOx, SOx and particulate emissions are acceptably low.Thermal efficiency of PFBC technology, however, is not high enough among the advanced coal based power generation technologies, such as integrated coal gasification combined cycle power generation (IGCC), integrated coal gasification fuel cell power generation (IGFC). Net thermal efficiency of PFBC is near 40%, because inlet temperature of gas turbine is limited. On the contrary, IGCC or IGFC gives high net thermal efficiency higher than 45%. In order to increase thermal efficiency, a new type of PFBC (advanced PFBC, A-PFBC) is now being developed. A-PFBC can improve inlet temperature of gas turbine and gives higher thermal efficiency as same as that of IGCC.Current PFBC technology seems to be not suitable for large scale commercial power generation, because of its higher construction and operational cost. It is very difficult to scale-up PFBC unit to very large scale as same as conventional pulverized coal combustion system. Other usage of PFBC may be more possible, because PFBC has high potential in the flexibility of fuel. Medium scale PFBC less than 50MWe is another choice. It can burn wide variety of fuels including wastes, and produces electricity and heat.In order to improve PFBC technology, fundamental research works are needed. Fundamental research on combustion behaviors of wide variety of fuels, combustion rate, agglomeration are presented.

「ハイパーコール利用高効率発電システム開発」プロジェクトの現状と展望

「ハイパーコール利用高効率発電システム開発」プロジェクトの現状と展望

Characteristics and economic evaluation of CO2‐capturing power generation systems using solar thermal energy and gasified coal

AbstractThis paper describes the evaluation results of CO2‐capturing power generation systems which use solar thermal energy and gasified coal as the input energy. The following two power generation systems have been proposed and evaluated from the characteristic and economic points of view: a CO2‐capturing hybrid power generation system (proposed system I), and a CO2‐capturing three‐stage heat‐utilizing power generation system (proposed system II). In evaluation, a conventional integrated coal‐gasification combined cycle power generation system (IGCC system) is adopted as the reference system. The proposed systems are assumed to be constructed in Albuquerque, U.S. and Osaka, Japan. The net coal‐to‐electricity efficiency has been estimated to be 51.0% for the proposed system I, and to be 40.1% for the proposed system II on higher heating value basis, whereas the efficiency of the conventional system is estimated to decrease from 43.7% to 32.7% when the CO2 generated is captured. Taking the IGCC system without CO2 capture as the reference system, the cost of CO2 emission reduction of the proposed systems I and II in Albuquerque are estimated to be 22,100–23,800 yen/t‐C and 21,800–23,000 yen/t‐C, respectively, and that in Osaka to be 37,000–38,700 yen/t‐C and 23,300–24,500 yen/t‐C, respectively. It has been shown that these are lower than the cost of CO2 emission reduction of the IGCC system with CO2 capture by 43,800–48,400 yen/t‐C. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 1–13, 2002

Design and evaluation of combined cycle system with solid oxide fuel cell and gas turbine

This study describes the basic design/evaluation of a combined cycle power generation system using solid oxide fuel cells in conjunction with a gas turbine. Factors included are system performance and cost/energy pay-back times (CPT/EPT). Total generation efficiency ( E th) was analyzed from the standpoint of plant size, cell performance, working pressure/temperature, steam carbon ratio, fuel/air utilization ratios ( U f/ U a) and turbine inlet temperature (TIT). A calculation method for determining the system life cycle cost and input energy requirements is also proposed. Results show that E th is higher than that for conventional power plants; it has a working temperature/ pressure of 1073 K/0.4 MPa, E th=68.3% with CPT=9.3 years and EPT=0.71 years with load following capability from 60 to 121% nominal load. The main parameters for determining E th, CPT and EPT were found to be working temperature, cell performance, U a and TIT limitation. Also discussed in detail are development areas and targets.

Study on SOFC Combined Cycle Power Generation System. 2nd Report. Study of Influence of System Configuration on Performance of SOFC Power Plants.

System analysis of Solid Oxide Fuel Cell (SOFC)/Gas Turbine (GT) combined cycle power generation systems were carried out by means of numerical simulation method. In the first report, the influence of the SOFC operation conditions on the efficiencies of the system was discussed. This report studied the influence of the system configuration on the system performance. First, the system performance using internal reforming was compared with that using external reforming. Next, the system performance using cathode gas recycling or anode gas recycling was studied. As a result, it was clarified that the use of the internal reforming or gas recycling was effective to raise the gas turbine inlet temperature, but did not always make the system efficiency improvements. However, when the Heat Recovery Steam Generator is installed in the system using anode gas recycling, the efficiency of the SOFC/GT/Steam Turbine combined cycle power generation system was estimated to be over 65%.

Study on SOFC Combined Cycle Power Generation System. 1st Report. System Analysis by Numerical Simulation.

To study system configurations and operation conditions of a Solid Oxide Fuel Cell (SOFC)/Gas Turbine (GT) combined cycle power generation system, system analysis was carried out by means of numerical simulation method. In the system analysis, the performance of SOFC was simulated with the expected SOFC module performance. This report discussed the influence of the SOFC operation conditions, such as fuel utilization and current density, on the efficiencies based on the output of the gas turbine and the system. As a result, it is clarified that elevating the SOFC operation pressure is effective for improvement of system performance, mainly because the GT performance becomes higher. The system efficiency is estimated at around 60% (HHV) at 0.98 MPa of SOFC operation pressure.

98/02543 Materials issues in coal-fired combined cycle power generation systems. Laboratory versus plant testing : Simms, N. J. and Oakey, J. E. Mater. Sci. Forum, 1997, 251–254, (Pt. 2, High Temperature Corrosion and Protection of Materials 4, Pt. 2), 543–550

98/02543 Materials issues in coal-fired combined cycle power generation systems. Laboratory versus plant testing : Simms, N. J. and Oakey, J. E. Mater. Sci. Forum, 1997, 251–254, (Pt. 2, High Temperature Corrosion and Protection of Materials 4, Pt. 2), 543–550

98/02047 Coal gasification apparatus, coal gasification method and integrated coal gasification combined-cycle power generation system

98/02047 Coal gasification apparatus, coal gasification method and integrated coal gasification combined-cycle power generation system

98/01205 Coal gasification combined-cycle power generation system: Abe, T. Jpn. Kokai Tokkyo Koho JP 09,228,807 [97,228,807] (Cl. F01K23/10), 2 Sep 1997, Appl. 96/38,356, 26 Feb 1996, 4 pp. (in Japanese)

98/01205 Coal gasification combined-cycle power generation system: Abe, T. Jpn. Kokai Tokkyo Koho JP 09,228,807 [97,228,807] (Cl. F01K23/10), 2 Sep 1997, Appl. 96/38,356, 26 Feb 1996, 4 pp. (in Japanese)

Research and Development of a New Coal Based Combined Cycle Power Plant Concept.

We propose a new coal-fired combined cycle power generation system featuring dust removal of high-temperature gas and wet desulfurization at the gas turbine outlet with the aim of improving the efficiency of the conventional IGCC system and reducing its construction cost. To study its feasibility, we conducted a fundamental study on the effects of alkali metal vapors in coal-derived gas on gas turbine blades and also studied remedial technology. The results of hot corrosion tests suggest that if the alkali metal vapor concentration in combustion gas is approximately 1 ppm or less current anticorrosion coating technology provides sufficient protection in practical use. The results of alkali removal tests show that 70% or higher removal rate can be achieved, which was considered a requirement for implementing the proposed system.

鉄・亜鉛系酸化物脱硫剤の高温下におけるＨ２Ｓ除去特性

An integrated coal gasification molten carbonate fuel cells power generation system (IG-MCFC) has higher thermal efficiency than an integrated coal gasi-fication combined cycle power generation system (IGCC). In IG-MCFC, it is necessary to remove sulfur compounds (H2S, COS) so that there are less than 1 ppm. Iron oxide sorbents developed in IGCC can not achieve this. New sorbents need to be developed for this reason.A zinc element has high ability for sulfur removal to less than 1 ppm. We prepared mixed oxide sorbents containing iron and zinc, and evaluated the characteristics of H2S removal.1. A zinc element, which was added to the sorbents as zinc ferrite (ZnFe204), had the highest reactivity.2. Silica added to zinc ferrite had much effect on protecting of carbon depositions.3. Zinc ferrite sorbents could remove H2S down to less than 1 ppm.4. Zinc ferrite sorbents after regeneration couldalso have less than 1 ppm.5. The sorbents' desulfurization performance after regeneration was influenced by change of the specific surface area caused by regeneration.

Materials Issues in Coal-Fired Combined Cycle Power Generation Systems: Laboratory versus Plant Testing

Pour pouvoir developper de nouveaux systemes generateurs d'energie utilisant la combustion du charbon il faut que tous les composants soient fabriques a partir des materiaux convenables et que les materiaux utilises aient des performances en service previsibles. La duree de vie de beaucoup de ces composants peut etre limitee par la corrosion a haute temperature provoquee par les particules de charbon, les depots et les especes gazeuses provenant de la combustion du charbon. Cet article presente les methodes d'essai developpees pour evaluer les performances des materiaux dans les environnements crees par les nouveaux systemes de productions d'energie et en particulier les essais appropries qui peuvent simuler les environnements en question. Les composants ainsi etudies sont les echangeurs de chaleur (dans les bruleurs a lit fluidise et dans les gazeificateurs), les elements du filtre a gaz chaud et des tuyeres dans les turbines a gaz. En outre les avantages relatifs des essais industriels et des essais en laboratoire pour l'evaluation et la modelisation des performances reelles des materiaux sont decrits.

97/03089 Characteristics of a CO 2-recovering combined cycle power generation system when its CO 2 recovery rate is changed

97/03089 Characteristics of a CO 2-recovering combined cycle power generation system when its CO 2 recovery rate is changed