Gas Turbine Cogeneration System Research Articles

Effectiveness of a Micro Gas Turbine Cogeneration System using in a Residential Area

For energy conservation and CO2 reduction, cogeneration systems may be useful. This paper shows the effectiveness of the cogeneration system, used in a residential area and designed to supply heat by hot water pipelines. The cogeneration system consists of a micro gas turbine (MGT) generator and a boiler. Entire heat load is supplied by the MGT or boiler, while an electric load may be supplied by an electric power company. Optimal diameter of the hot water pipeline becomes large when the load density becomes low. Total heat supply loss is less then 10% for moderate temperature region. However, it exceeds 20% for a sparse load in the cold region. The MGT should generates heat just required by the load for the primary energy or cost minimum operation. In the moderate temperature region, primary energy reduction ratio is positive in almost all cases, while it becomes negative in the cold region. On the other hand, CO2 emission almost always decreases in some extent. In the warm or moderate temperature region, MGT cogeneration systems are effective for energy conservation. They are also effective for CO2 reduction in almost all cases.

421 バイオガス・コジェネレーションシステムの性能解析(エネルギー有効利用(1))

This study shows an impact and a basic performance analysis of micro gas turbine (MGT) cogeneration system (CGS) and methane hydrate storage in the sewage treatment facility under various temperature conditions. The results show that, in either temperature condition, by only using biogas produced from the facility as a fuel, and methane hydrate storage method as a solution for the unbalance of biogas produced, MGT-CGS was sufficiently capable to cover all the total heat demand of the facility. On the biogas utilization and economic point of views, compared to the conventional system it was found that MGT-CGS was effective system and could reduce 82〜100% of unused biogas and 21〜33% of electrical demand. Whereas, for methane hydrate storage method, 3〜5% from reduced electricity was required. While adopting an actual data as a part of the calculation procedure, results of the performance analysis are shown in this paper.

下水処理施設におけるマイクロガスタービンコジェネレーションシステムの性能評価 : 年間平均気温の異なる地域での性能解析(熱工学,内燃機関,動力など)

This study shows an impact and a basic performance analysis of micro gas turbine (MGT) cogeneration system (CGS) in the sewage treatment facility under various temperature conditions. The results show that, in either temperature condition, by only using biogas produced from the facility as a fuel and methane hydrate storage method as solution for the unbalance of biogas produced, MGT-CGS is sufficiently capable to cover all the total heat demand of the facility. On the biogas utilization and economic point of views, MGT-CGS is effective in either temperature conditions but the effectiveness is decreasing when the ambient temperature condition is increasing. It is most effective in cold temperature condition with almost 100% of the biogas is utilized, whereas in high temperature condition due to low heat demand, comparing to the conventional system approximately only 42〜79% of unutilized biogas is decreased. While adopting an actual data as a part of the calculation procedure, results of the impact and performance analysis are shown in the paper.

The effect of elevated inlet air temperature and relative humidity on cogeneration system

The effect of elevated inlet air temperature and relative humidity on a gas turbine (GT) cogeneration system performance was investigated. The analysis was carried out on a GT of a capacity 171 MW at ISO condition, which is integrated with a dual pressure heat recovery steam generator (HRSG), the cogeneration system had been tested under Kuwait summer climate conditions. A computational model was developed and solved using engineering equation solver professional package to investigate the performance of a dual pressure GT-HRSG system. The suggested HRSG is capable of producing high-pressure superheated steam at 150 bar and 510°C to operate a power generation steam turbine cycle, and a medium pressure saturated steam at 15 bar to run a thermal vapor compression (TVC) desalination system. In this research, the influence of elevated inlet air temperature and relative humidity on the energy assessment of the suggested cogeneration system was thoroughly investigated. Results indicated that operating GT under elevated values of inlet air temperatures is characterized by low values of net power and thermal efficiency. At elevated inlet air temperatures, increasing relative humidity has a small positive impact on GT cycle net power and thermal efficiency. Integrating the GT with HRSG to generate steam for power generation and process heat tends to increase energy utilization factor of the system at elevated inlet air temperatures. Increasing inlet air temperature plays a negative impact on power to heat ratio (PHR), while relative humidity has no effect on PHR. Copyright © 2009 John Wiley & Sons, Ltd.

The Optimal Operation Criteria for a Gas Turbine Cogeneration System

The study demonstrated the optimal operation criteria of a gas turbine cogeneration system based on the analytical solution of a linear programming model. The optimal operation criteria gave the combination of equipment to supply electricity and steam with the minimum energy cost using the energy prices and the performance of equipment. By the comparison with a detailed optimization result of an existing cogeneration plant, it was shown that the optimal operation criteria successfully provided a direction for the system operation under the condition where the electric power output of the gas turbine was less than the capacity

Second law analysis of a natural gas-fired gas turbine cogeneration system

The influence of operating conditions such as reheat, intercooling, ambient temperature and pressure ratio are analyzed from a second law perspective on the performance of a natural gas-fired gas turbine cogeneration system. The effect of these operating parameters on carbon dioxide emissions is also discussed. The second law efficiency of gas turbine cogeneration system increases markedly with reheat option. Higher pressure ratios lead to decreased second law cogeneration efficiency but this effect can be reduced with a higher level of reheat option. The effect of intercooling on second law efficiency is strongly related to pressure ratio with higher pressure ratios significantly decreasing efficiency. The second law efficiency is not so sensitive to the environment temperature for levels of reheat or intercooling greater than 50%. Copyright © 2009 John Wiley & Sons, Ltd.

E106 MICRO GAS TURBINE CO-GENERATION SYSTEM AT SAPPORO CITY UNIVERSITY UNDER SERVICE CONDITIONS(Distributed Energy System-1)

A micro gas turbine co-generation system (MGT-CHP) with a heat storage tank was demonstrated in Sapporo City University. Operating schedule of MGT-CHP was determined from the gas consumption ratio measured in the former body of the Sapporo City University. The schedule consists of winter-, mid-, and summer- terms. Results of scheduled operation showed that even in winter term when heat demand was largest in year period, CHP system efficiency was less than 50%, which was less than the target value. In winter term, early start of the system, i.e. 4 O'clock in the morning, was found to improve the total efficiency of hot water heating system and CO_2 reduction. Based on the experience, we changed the schedule timer to new programmable logic controller (PLC). PLC can take into account the temperature outside and room temperature to control MGT-CHP start time. We plan to operate the algorism of MGT that will totally improve the efficiency of hot water heating system and CO_2 reduction.

911 マイクロガスタービンコジェネレーションシステムのプログラマブルロジックコントローラの利用によるCO_2削減効果の改善(OS12-(1) 流体工学・熱流体,オーガナイズドセッション)

AIST Energy Technology Research Institute (ETRI) has been demonstraing micro gas turbine co-generation system (MGT-CGS) in Sapporo City University since 2006. In 2009, we changed the schedule timer for MGT-CGS to new programmable logic controller (PLC) to improve CO_2 reduction. Input signals to PLC were temperatures inside and outside and electric powers, and output signals were relays for MGT-CGS and the heat strorage system. This paper showed some design changes to introduce instruments in the campus, some construction plans to discuss, results and interlocking process between MGT-CGS and heat strage system.

A novel high-performance low-NOx fuel-rich/fuel-lean two-stage combustion gas and steam turbine system for power and heat generation

This paper proposes, describes, and analyses a novel high temperature and performance reheat gas turbine (GT) cogeneration system. This newly proposed system employing two-stage fuel-rich and fuel-lean combustion system is named as the ‘Fuel Rich-Lean Combustion Reheat GT Cogeneration System’ (RLCC). Energy and exergy analyses (the latter mainly to evaluate and demonstrate the reduction in exergy loss of this combustion process compared with conventional single-stage and fuel lean-lean combustion) of the proposed cogeneration system were performed and compared with a conventional cogeneration system. The proposed RLCC system is predicted to have an overall power generation efficiency of up to 53.0 per cent (low heating value (LHV) basis), exergy efficiency up to 61.9 per cent, and specific power up to 524.3 kJ/kg. Compared with a conventional cogeneration (CGC) system, its energy utilization efficiency was as high as 95.0 percent, 4.0 percentage points higher than that of the CGC system, the overall power generation efficiency was higher by 6.2 percentage points, and the exergy efficiency was higher by 7.8 percentage points, and the overall power-based NO x emissions was reduced by up to 34.0 per cent.

Optimization of a regenerative gas-turbine cogeneration system based on a new exergetic performance criterion: Exergetic performance coefficient

A performance analysis and an optimization based on a new exergetic performance criterion named exergetic performance coefficient (EPC) have been carried out for an irreversible regenerative gas-turbine cogeneration system. The EPC objective function defined as the total exergy output per unit loss rate of availability is taken as the optimization criterion. The design parameters and performances under optimal conditions have been investigated and the results obtained are compared with those obtained using the alternative criteria given in the literature. It is shown that for the regenerative gas-turbine cogeneration system, a design based on the maximum EPC conditions is more advantageous from the viewpoint of entropy generation rate, exergy efficiency, and investment cost.

Combined First and Second-Law Analysis of Gas Turbine Cogeneration System With Inlet Air Cooling and Evaporative Aftercooling of the Compressor Discharge

A conceptual gas turbine based cogeneration cycle with compressor inlet air cooling and evaporative aftercooling of the compressor discharge is proposed to increase the cycle performance significantly and render it practically insensitive to seasonal temperature fluctuations. Combined first and second-law approach is applied for a cogeneration system having intercooled reheat regeneration in a gas turbine as well as inlet air cooling and evaporative aftercooling of the compressor discharge. Computational analysis is performed to investigate the effects of the overall pressure ratio rp, turbine inlet temperature (TIT), and ambient relative humidity φ on the exergy destruction in each component, first-law efficiency, power-to-heat ratio, and second-law efficiency of the cycle. Thermodynamic analysis indicates that exergy destruction in various components of the cogeneration cycle is significantly affected by overall pressure ratio and turbine inlet temperature, and not at all affected by the ambient relative humidity. It also indicates that the maximum exergy is destroyed during the combustion process, which represents over 60% of the total exergy destruction in the overall system. The first-law efficiency, power-to-heat ratio, and second-law efficiency of the cycle significantly vary with the change in the overall pressure ratio and turbine inlet temperature, but the change in relative humidity shows small variations in these parameters. Results clearly show that performance evaluation based on first-law analysis alone is not adequate, and hence, more meaningful evaluation must include second-law analysis. Decision makers should find the methodology contained in this paper useful in the comparison and selection of advanced combined heat and power systems.

Renewable Fuel Utilization in a Cogeneration Arrangement with Hydrate Storage Method

According to the third conference of parties (COP3), Japan has set a target of reducing greenhouse gas emissions by 6% by the year 2010. Many believe that the bulk utilization of fossil fuel influences to the damaging environmental effect. The objective of this paper is to propose an effective method for this goad which is possible to clarify a noticeable utilization of renewable fuel in a micro gas turbine cogeneration system in cold region. Moreover, analysis of renewable fuel, biogas production indicates that production amount becomes largest in hot season, while the total heat energy demand is lowest on during three years. Biogas storage is also adapted for the delay between peak energy supply and demand. Biogas hydrate formation is examined by resource from laboratory experiments and simulation of integration into an existing cogeneration arrangement. The proposed system can be successfully supported the use and reuse of renewable fuel for providing to substantial emission and clean development mechanism for reducing greenhouse gas emission.

Economic evaluation for adoption of cogeneration system

An optimal planning for gas turbine cogeneration system was applied to find whether or not the adoption of the system to an office building or hotel in Seoul, Korea is profitable. The planning problem considered in this study is to determine the optimal configuration of the system equipments and optimal operational policy of the system when the annual energy demands of electric power, heat and cooling are given a priori. The optimal configuration of the system equipments has been determined based on annual cost method with proper choice of representative energy demand patterns obtained for the building and hotel in a 1-year period. A mixed-integer linear programming and the branch and bound algorithm have been used to obtain the optimal solution. The planning method employed here may be applied to making decision on the adoption of the cogeneration plant to any specific office building or hotel.

An appraisal method of exergy cost minimisation for co-generation systems

This study introduces an exergy cost-minimisation appraisal method for a simple gas turbine co-generation system. Optimisation of a gas turbine co-generation system of the electric output class of 17 MW is examined for a variety of turbine inlet temperatures of 950–1,300°C. An optimum value of the turbine inlet temperature exists for exergy cost minimisation and is estimated to be 1,200°C since the manufacturing price of the gas turbine increases greatly above 1,300°C. This fact shows that the rising manufacturing cost of the gas turbine constitutes an important effect for future development of higher temperature systems.

寒冷地集合住宅へマイクロガスタービンコジェネレーションを導入した際のＣＯ２削減可能性の評価

Introducing a co-generation system is an effective choice for reducing energy derived CO2 emissions and operating costs for the residential and commercial sectors. In this paper, the possibilities of CO2 emission and operating cost reductions were investigated for the case of a micro gas turbine co-generation system being introduced into a 33 household apartment building located in Sapporo, one of the coldest districts in Japan, which demands a lot of energy in winter for hot-water supply and heating.The results were compared with that of the existing system which is composed of an electricity grid and hot water boilers. The CO2 emissions and operating costs of the co-generation system varied according to the ratio of electricity supply from the grid and MGT, MGT generation efficiencies and the season of the year. Using an MGT with an electricity generation efficiency of 35%, a reduction of 10% (23.4 tonne-CO2/y) of CO2 emissions and 9.4% (433ky) of operating costs could be attained compared with the existing system. In the case of a generation efficiency of 30%, a reduction of 3.4 tonne-CO2/y is expected at the same level of operating cost as the existing system. But in the case of a generation efficiency of 25%, there was no signifi-cant reduction in CO2 emission.

ガスタービン導入による省エネ

ガスタービン導入による省エネ

Development of Mucro Gas Turbine Co-Generation System

Development of Mucro Gas Turbine Co-Generation System

Development of efficiency-enhanced cogeneration system utilizing high-temperature exhaust-gas from a regenerative thermal oxidizer for waste volatile-organic-compound gases

We have developed a gas-turbine cogeneration system that makes effective use of the calorific value of the volatile organic compound (VOC) gases exhausted during production processes at a manufacturing plant. The system utilizes the high-temperature exhaust-gas from the regenerative thermal oxidizer (RTO) which is used for incinerating VOC gases. The high-temperature exhaust gas is employed to resuperheat the steam injected into the gasturbine. The steam-injection temperature raised in this way increases the heat input, resulting in the improved efficiency of the gas-turbine. Based on the actual operation of the system, we obtained the following results: • Operation with the steam-injection temperature at 300 °C (45 °C resuperheated from 255 °C) increased the efficiency of the gasturbine by 0.7%. • The system can enhance the efficiency by 1.3% when the steam-injection temperature is elevated to 340 °C (85 °C resuperheated). In this case, up to 6.6 million yen of the total energy cost and 400 tons of carbon dioxide (CO 2) emissions can be reduced annually. • A gas-turbine cogeneration and RTO system can reduce energy consumption by 23% and CO 2 emission by 30.1% at the plant.

05/01157 A modern injected steam gas turbine cogeneration system based on-exergy concept

05/01157 A modern injected steam gas turbine cogeneration system based on-exergy concept

Pre feasibility of cogeneration in a hotel in Bangladesh

Pre feasibility of cogeneration in a hotel in Bangladesh was carried out. Information on steam and electricity consumption in a hotel was collected through site visits and surveys via questionnaire. Historical energy consumption data shows that the power to heat ratio of the plant was 0.35. For average power to heat ratio of 0.35, three types of the prime movers i.e. steam turbine, reciprocating engine and gas turbine cogeneration system was considered. From the sensitivity analysis the potential cogeneration alternatives of the hotel, the reciprocating engine power match option meeting power requirement of 525 kW to be the most suitable co-generation system. It represents an initial investment of 0.034 billion Taka (1 US $ = Tk 58) and leads to an internal rate of return of 41.8%. Keywords: cogeneration, sensitivity analysis,energy class. Nepalese Journal of Engineering Vol.1(1) 2005 pp. 76-79