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Go to Editorial ManagerThe heat lost from gas turbine power plants with exhaust gases represents the most important source for lowering its thermal efficiency. Also, the gas turbine thermal efficiency affected significantly with the ambient surrounding temperature. Al-Najybia gas-turbine power plant in Basrah, Iraq is choosing as a case study. The power plant consists of four units with a capacity of 125 MW for each unit. In the present study, all the calculations are performed for one unit only. Firstly the thermal impact is studied in terms of energy analysis for Al-Najybia gas turbine power plant (GTPP) for different ambient temperature for twelve months. Also, the economic loss a companied the heat lost with exhaust gases for different ambient temperature are estimated. Secondly, the thermo-economic improvement from coupling the GTPP with a heat recovery system is studied. For gas-steam combined cycle, the performance and economic analysis are performed. The results show that, the output power and thermal efficiency are decreased by 0.97 MW and 0.0726% respectively for each unit temperature rise of the ambient temperature. For the combined gas-steam power plant the percentage increasing of the thermal efficiency is approximately 46.4%. The results indicate the combined cycle power plant (CCPP) is very important to increase electrical capacity. From the economic analysis, the economic gain due to using HRB is 75757 $ per month.
Thermal steam power plants represent the most important and dependable type for supplying the base load of electricity around the world. The thermos-economic analysis is an important tool for improving the performance of thermal steam power plants. In the present study, a thermo-economic analysis of a simple steam power plant for different boiler pressure was performed. The analysis comprises the energy, exergy, entropy, economics, and exergy-economic of a simple cycle steam power plant for different boiler pressure. The analysis was performed for a simple steam power plant with the constant output power of 10 MW and the boiler pressure is varied from 10 bar to 100 bar by a step of 10 bar. For each boiler pressure and constant output power, firstly, the fuel mass flow rate, steam flow rate, energy and exergy efficiency, and cost of electricity were calculated. Secondly, entropy generation, exergy destruction, and exergy efficiency for each component were calculated. Finally, exergy destruction economics for each component of the plant was performed. The results reveal that increasing the boiler pressure from (10 to 100 bar) for constant output power reduces the cost of electricity from (0.135 to 0.1025 $/kWh) due to a decrease in the fuel mass flow rate and an improvement in the thermal cycle and exergy efficiency. Also, when the boiler pressure increases, the exergy destruction for the pump increases, the exergy destruction for the boiler decreases, the exergy destruction for the turbine increases, and the exergy destruction for the condenser decrease.
The efficiency of gas turbine units is highly affected by the variation of ambient temperature. Increasing the ambient temperature decreasing the efficiency of gas turbine. Cooling the inlet air to the compressor of the gas turbine units is an essential and economical technique for improving its efficiency. Al-Rumaila gas turbine power plant was located in Basrah city, Iraq, which is characterized by its hot climates for more than six months during the year. A novel upstream inlet air cooling system was applied and tested for Rumaila gas turbine power plant. This article represents a thermo-economic evaluation of applying upstream inlet air cooling system. The analysis is based on the test results for operating single unit of Rumaila gas turbine power plant using upstream inlet air system for cooling. The test was performed during July of 2019 for 90 minutes of operation period with ambient temperature of 45 °C. The evaluation analysis shows that, the power output increased from 217.71 MW to 250.11 MW during the period test with percentage increase in power by 15%. This increase in power output led to net economic gains is approximately 1000 $/h.
In the present research, a Matlab program with a graphical user interface (GUI) has been established for studying the performance of a solar tower power plant (STPP). The program gives the ability for predicting the performance of STPP for different tower dimensions, ambient operating conditions and locations. The program is based on the solution of a mathematical model derived from the heat and mass balance for the tower components. The GUI program inputs are; tower dimensions, solar radiation, ambient temperature, pressure, wind velocity, turbine efficiency, emissivity and absorptivity for collector and ground and thermal conductivity and thickness for ground. However, the GUI program outputs are; temperature and pressure differences across the collector and tower, velocity in the tower, density of air in collector outlet, mass flowrate of air, efficiency for collector and tower, the overall efficiency and output power of STPP. The effect of the geometrical dimensions of STPP and some climatic variables on the plant performance was also studied. The results show that the output power increases with increasing the collector diameter, chimney diameter and solar radiation by an increasing of 0.282 kW/m, 0.204 kW/m and 0.046 kW/(W/m2) respectively.
In this work, both energy and exergy analyses have been carried out on General Electric (GE) gas turbine unit found in Khor Al-Zubair gas turbine power plant located in Basra, Iraq. The analysis covers the ISO (international standards organization) operating conditions in addition to actual operating data recorded for one month in hot season July 2016. The feasibility of adopting a vapor compression cycle (VCC) for cooling the intake air is evaluated. Generally, the study reveals an obvious drop off for most plant performance characteristics while operating during the hot season. Energy and exergy analyses show that adopting the vapor compression cycle to enhance Khor Al-Zubair GE unit could improve the power output by 20% and 27% in case of part-load and full-load conditions respectively. Both of first and second law efficiencies could be improved by 3.5% at part- load and 9% at full load. The expected cooling load needed for the unit is in the range of 2697 to 3024.5 TR according to part- load and full-load operation respectively. Only total irreversibility of the unit is expected to increase in case of adopting VCC and this will not impair the improvement in second law efficiency of the unit. Among the unit components, combustion chamber has the largest computed irreversibility. Further improvement is recommended by utilizing the released heat energy to the atmosphere, which is characterized by significant work potential.
A mathematic model is presented for solar updraft tower power plant with water-storage system. This model is developed to evaluate the effect of geometrical parameters of the solar tower power plant and thermal storage system as well as the wind velocity on the power production of the plant. The analysis based on variable solar incident radiation along the day. The results show that the tower tall, the tower diameter, the wind velocity, and the collector diameter have a significant effect on the power production while lhe thickness of the water-storage layer is shifted the peak value of the output power far away from mid-day and more smoothing tha output power curve. The results are compared with other model and experimental data. A good agreement is obtained.
The solar chimney is a natural draft device that uses solar radiation to provide upward momentum to the in-flowing air, thereby converting the thermal energy into kinetic energy through an air turbine which in turn can be converted into electrical energy. The main parts of the solar chimney power plant are a large circular solar collector, a tall chimney, and an air turbine. In this paper, a theoretical study was performed to evaluate the performance of a solar chimney power plant system in Basrah City, where sunny days and solar radiation are high. A mathematical model was developed to study the effect of various parameters on the output power of the solar chimney. I1 was found that the output power depends strongly on the chimney tall and the difference between the collector air temperature and the ambient air temperature as well as the outside heat transfer coefficient, which essentially depends on the wind speed.
This study presents solar chimney power plant integrated with sea water desalination system. A simple mathematical model is based on the conservation of mass and energy. The results show that the integrated system of solar chimney power plant and solar still can achieve simultaneously. The analysis is performed for both summer and winter at latitude 30 o N. It’s noted that, the water layer thickness is of a significant effect on the fresh water productivity while the dimensions of solar chimney and the solar collector are of a minor effect. The productivity of fresh water and output power for summer are the highest. The present work is compared with experimental data of the other work and showed a good agreement.
Failures in the steam tubes of boiler furnaces in Najebia power plant was studied experimentally. Visual examination, mechanical tests, microscopic test and chemical analyses were performed. Visual examination showed the types of failure in the tubes. Tensile and hardness tests were performed to estimate the variation in the mechanical properties of the tubes metal and compared with the new tubes. Microscopic test for the failed tubes used to recognize the difference in the microstructure to the metal of the tubes. Chemical analyses involved chemical composition of the tubes metal, river and feed water analyses, water treatment, fuel analyses and analysis of deposits and oxides on the external and internal sides. Overheating and wall thinning of the tubes resulted from oxygen escaping to the inner side of these tubes, and presence of deposits and oxides on the external and internal sides which led to failure was studied extensively. Engineering remedies were also given to confine the problem and to prevent it in future.
In this paper, energy and exergy concepts have been carried out on one of the largest gas turbine power plants in Iraq (Rumaila-Basra). Both ISO operating conditions as well as actual operating data recorded for one month in hot season are considered. Results indicate that a lot of heat energy accompanied with remarkable exergy is discharged to the atmosphere. Also, it is found that the combustion chamber has the largest exergy destruction among the plant components. Possibility of cooling the intake air drawn by the compressor and its effects on the plant performance is studied. The required cooling load is found to be in the range 3379 T.R for part load operation to 4723.3 T.R for full load operation.
The solar chimney power plant is one of the modern models studied on the world. This study presents an engineering and numerical analysis of solar chimney with different parameters. Also, it studies the comparison of two collector base shapes(circular and hexagonal) depend on the five storage material types and their effects on the heat transfer, velocity, efficiency, etc. inside the solar chimney system by considering the solar array intensity equations and the energy equation to calculate the heat transferred and stored by applying the laws of CFD. The finite volume method is used to analyze the geometry physical model by applying a commercial Fluent 6.3 code with Gambit 2.3. The obtained results show that the efficiency of solar chimney is increased by increasing the area of solar glassed collector with circular base shape than the others of polygonal or rectangular one because the circular was covered large area of system. So, the circular ground collector shape for thermal storage is the favour because it is the better to increase the velocity of entering air and to increase the efficiency of turbine. In addition to that the black Pebble storage plate is the better material for heat storage which is convected to air passed for operation of turbine than the other types aluminum, tar, copper and steel seriously.
The foundation of soil is considered safe when the factor of safety against shear failure is adequate and the settlement of the foundation should be tolerable and does not cause any unacceptable damage for the structure. The ultimate bearing capacity is defined as the maximum pressure which may be applied to the soil without causing neither a shear failure nor large settlement. In this research the bearing capacity of the soil at diesel power plant project in Al-Diwaniyah city by plate bearing test. The soil has been tested in the field in the locations of four foundations for circular tanks of diameter of 17m. The load is applied to the plate in four increments. In each increment; the load stays static for 15 minutes according to ASTM D1194-94 specification. The results showed that the plate settlements of the soil under three tanks were within the permitted settlement. The allowable bearing capacity of soils under these tanks were (117, 137 and 137) kPa respectively. While, the soil under the fourth tank was soft and the plate settled approximately 30 mm immediately after applying the first increment of load. Therefore the soil is considered improper and recommendations are suggested to improve it.
Shatt Al-Arab river has been used as the raw material for the drinking water, irrigation and fish purposes in Basrah city. Concurrently, this river has been polluted by domestic, farming and industrial waste. Three main factories lie on the bank of Shatt Al-Arab river: Al-Hartha Paper Mill, Hartha Power Station and Al-Najibia Power Plant. All these consume water from the river and return their wastewater back to it. The aim of this study is to assess the water quality of Shatt Al-Arab river and its suitability for drinking, irrigation and aquatic life through physicochemical analysis temperature, pH, EC, Total Dissolve Solid (TDS), Cl − , Na + , K + , Ca +2 , Mg+2, HCO 3 total hardness, Biological Oxygen Demand (BOD5), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD). BOD5 concentration near factories showed polluted water, unsafe and requiring costly treatment to use for drinking water. Sodium concentration is a key factor for irrigation, which represent by SAR and SSP. As SSP exceed 75.73 % in water near these factories, this could breakdown soil structure and can damage agriculture area. The high concentrations of BOD5 and COD could pose a threat to aquatic life and fishes. As Shatt Al-Arab river is used for different purpose, the result in this study showed polluted water near industrial areas. Therefore, it is recommended to have regular data on water quality for this river near these areas.