The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Totaro Goto - One of the best experts on this subject based on the ideXlab platform.
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ion exchange membrane electrodialytic salt production using brine discharged from a reverse osmosis seawater desalination plant
Journal of Membrane Science, 2003Co-Authors: Yoshinobu Tanaka, Reo Ehara, Sigeru Itoi, Totaro GotoAbstract:Abstract Operating parameters of an ion-exchange membrane electrodialytic salt manufacturing plant (NaCl production capacity: 200,000 t per year) using brine discharged from a reverse osmosis (RO) seawater desalination plant are discussed. The results were compared with the data obtained from a salt manufacturing plant using seawater. The specifications of the electrodialyzer are: the thickness of the desalting cell, 0.05 cm; the flow-pass length in a desalting cell, 2 m; effective membrane area, 2 m 2 ; overall osmotic coefficient of a membrane pair, 30 cm 4 /(eq. h); and solution velocity at the inlets of desalting cells, 5 cm/s. The electrolyte concentration at the inlets of desalting cells was set at 1.5 eq./dm 3 , which is consistent with the electrolyte concentration of brine discharged from a reverse osmosis seawater desalination plant. The energy consumed in the salt manufacturing process was assumed to be supplied by a simultaneous heat-generating electric power unit using a Back-Pressure Turbine. The number of evaporators (evaporation pans) was selected to minimize the electric power shortfall of the salt manufacturing process but to be larger than zero. The electric power shortage was assumed to be made up by purchased electric power, which is generated by a condensing Turbine. The energy consumption in a salt manufacturing process was obtained by adding the generation energy in the Back-Pressure Turbine, the evaporation energy in the No. 1 evaporator in multiple-effect evaporators, the condensing energy in the heater in the No. 1 evaporator and purchased energy. The energy consumption in a salt manufacturing process using the brine discharged from a reverse osmosis seawater desalinating plant was 80% of the energy consumption in the process using seawater. The optimum current density at which the energy consumption is minimized was 3 A/dm 2 for both electrodialyses of brine discharged from the reverse osmosis desalination plant and of seawater.
M Z Abdullah - One of the best experts on this subject based on the ideXlab platform.
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analysis of biomass residue based cogeneration system in palm oil mills
Biomass & Bioenergy, 2003Co-Authors: Z Husain, Z A Zainal, M Z AbdullahAbstract:Abstract Palm oil mills in Malaysia operate on cogeneration system using biomass residue as fuel in the boiler. The boiler produces high Pressure and temperature steam which expands in a BackPressure steam Turbine and produces enough electric power for the internal needs of the mill. The exhaust steam from the Turbine goes to an accumulator which distributes the steam to various processes in the mill. The study were made on seven palm oil mills in the Perak state in Malaysia. The primary objectives of the study are to determine boiler and Turbine efficiencies, energy utilization factor, oil extraction rate and heat/power ratio for various palm oil mills working under similar conditions and adopting same processes. The palm oil industry is one of those rare industries where very little attempt is made to save energy. The energy balance in a typical palm oil mill is far from optimum and there is considerable scope for improvement. Bench-marking is necessary for the components in the mill. Energy-use bench-marking can give an overview of energy performance of the mills. The calculations were done to get net gain in power when Back Pressure Turbine is replaced by a condensing Turbine. It was found that the boiler and Turbine have low thermal efficiencies compared to conventional ones used in power plants due to non-homogeneity and non-uniform quality of the fuel. The extraction rate was around 0.188. The use of condensing Turbine increase the power output by 60% and the utilization factor was found to be 65% for the cogeneration system.
Zhihua Ge - One of the best experts on this subject based on the ideXlab platform.
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Energy and Exergy Evaluations of a Combined Heat and Power System with a High Back-Pressure Turbine under Full Operating Conditions
Energies, 2020Co-Authors: Shifei Zhao, Weishu Wang, Zhihua GeAbstract:High Back-Pressure technology is a promising method for the waste heat recovery of exhaust steams in combined heat and power systems. In this research, a 300 MW coal-fired subcritical combined heat and power system was selected as the reference system, and modeled in EBSILON professional. Then, energy-based and exergy-based performances of the high Back-Pressure system and traditional combined heat and power system were compared under full operating conditions. Moreover, a novel exergy-based evaluation method, which considers the energy level of the heating supply, was proposed and applied to evaluate the two systems. Results show that: In design conditions, both the heating capacity and power output of the high Back-Pressure system were higher than those of the extraction condensing system, which led to 17.67% and 33.21% increments of the gross thermal efficiency and generation efficiency, respectively. Compared with the extraction condensing system, the exergy efficiencies of the high Back-Pressure system were 7.04–8.21% higher. According to the novel exergy-based evaluation, the exergy efficiencies for the generation of the high Back-Pressure system and extraction condensing system were 46.48% and 41.22%, respectively. This paper provides references for the thermodynamic performance evaluation of the combined heat and power system.
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energy analysis of cascade heating with high Back Pressure large scale steam Turbine
Energies, 2018Co-Authors: Zhihua Ge, Fuxiang Zhang, Jie He, Xiaoze DuAbstract:To reduce the exergy loss that is caused by the high-grade extraction steam of traditional heating mode of combined heat and power (CHP) generating unit, a high Back-Pressure cascade heating technology for two jointly constructed large-scale steam Turbine power generating units is proposed. The Unit 1 makes full use of the exhaust steam heat from high Back-Pressure Turbine, and the Unit 2 uses the original heating mode of extracting steam condensation, which significantly reduces the flow rate of high-grade extraction steam. The typical 2 × 350 MW supercritical CHP units in northern China were selected as object. The boundary conditions for heating were determined based on the actual climatic conditions and heating demands. A model to analyze the performance of the high Back-Pressure cascade heating supply units for off-design operating conditions was developed. The load distributions between high Back-Pressure exhaust steam direct supply and extraction steam heating supply were described under various conditions, based on which, the heating efficiency of the CHP units with the high Back-Pressure cascade heating system was analyzed. The design heating load and maximum heating supply load were determined as well. The results indicate that the average coal consumption rate during the heating season is 205.46 g/kWh for the design heating load after the retrofit, which is about 51.99 g/kWh lower than that of the traditional heating mode. The coal consumption rate of 199.07 g/kWh can be achieved for the maximum heating load. Significant energy saving and CO2 emission reduction are obtained.
Xiaoze Du - One of the best experts on this subject based on the ideXlab platform.
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energy analysis of cascade heating with high Back Pressure large scale steam Turbine
Energies, 2018Co-Authors: Zhihua Ge, Fuxiang Zhang, Jie He, Xiaoze DuAbstract:To reduce the exergy loss that is caused by the high-grade extraction steam of traditional heating mode of combined heat and power (CHP) generating unit, a high Back-Pressure cascade heating technology for two jointly constructed large-scale steam Turbine power generating units is proposed. The Unit 1 makes full use of the exhaust steam heat from high Back-Pressure Turbine, and the Unit 2 uses the original heating mode of extracting steam condensation, which significantly reduces the flow rate of high-grade extraction steam. The typical 2 × 350 MW supercritical CHP units in northern China were selected as object. The boundary conditions for heating were determined based on the actual climatic conditions and heating demands. A model to analyze the performance of the high Back-Pressure cascade heating supply units for off-design operating conditions was developed. The load distributions between high Back-Pressure exhaust steam direct supply and extraction steam heating supply were described under various conditions, based on which, the heating efficiency of the CHP units with the high Back-Pressure cascade heating system was analyzed. The design heating load and maximum heating supply load were determined as well. The results indicate that the average coal consumption rate during the heating season is 205.46 g/kWh for the design heating load after the retrofit, which is about 51.99 g/kWh lower than that of the traditional heating mode. The coal consumption rate of 199.07 g/kWh can be achieved for the maximum heating load. Significant energy saving and CO2 emission reduction are obtained.
M.a. Habib - One of the best experts on this subject based on the ideXlab platform.
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First- and Second-Law Analysis of Steam-Turbine Cogeneration Systems
Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 1994Co-Authors: M.a. HabibAbstract:The paper presents an analysis of a cogeneration plant. The performance of the plant is compared to a conventional plant with separate production of process heat and power. The analysis is first- and second-law based and, therefore, quantifies the irreversibilities of the different components of each plant. In the cogeneration plant, the heat required in the boiler can be obtained either from fuel firing (condensing or Back-Pressure Turbine plant) or from exhaust gases of a simple gas Turbine (gas Turbine cogeneration plant). The present study compares the two methods. The influence of the heat-to-power ratio and the process Pressure on the thermal efficiency, utilization factor, and irreversibilities of the different components of each plant is presented. The results show that the total irreversibility of the cogeneration plant is lower by 38 percent compared to the conventional plant. This reduction in the irreversibility is accompanied by an increase in the thermal efficiency and utilization factor by 25 and 24 percent, respectively. The results show that most irreversible losses are due to boiler.
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Thermodynamic analysis of the performance of cogeneration plants
Energy, 1992Co-Authors: M.a. HabibAbstract:We present an analysis of two different cogeneration schemes. A comparison is made with a conventional plant of separate units for producing process heat and power. Use of the first and second laws quantifies the irreversible losses. In the cogeneration schemes, the required process heat is obtained either from a boiler and a Back-Pressure Turbine or from a combined-cycle gas Turbine. The effects of the process Pressure and heat-to-power ratio on performance are presented. The performance of the different schemes is analysed in view of the first- and second-law efficiencies, cogeneration efficiency and irreversibility rates for the different components in each plant. The irreversible losses occur mostly in the boiler and combustion chamber and are greatly reduced in a gas-Turbine cogeneration unit.
