scholarly journals Efficiency and Losses Analysis of Steam Air Heater from Marine Steam Propulsion Plant

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3019 ◽  
Author(s):  
Josip Orović ◽  
Vedran Mrzljak ◽  
Igor Poljak
Keyword(s):  
Ambient Temperature ◽  
Power Plants ◽  
High Energy ◽  
Exergy Efficiency ◽  
Flue Gases ◽  
Exergy Destruction ◽  
Air Heater ◽  
Air Heating ◽  
Wide Range ◽  
Steam System

Air heaters are commonly used devices in steam power plants. In base-loaded conventional power plants, air heaters usually use flue gases for air heating. In this paper, the air heater from a marine steam propulsion plant is analyzed, using superheated steam as a heating medium. In a marine propulsion plant, flue gases from steam generator are not hot enough for the air heating process. In a wide range of steam system loads, the analyzed steam air heater has low energy power losses and high energy efficiencies, ranging from 98.41% to 99.90%. Exergy analysis of the steam air heater showed that exergy destruction is quite high, whereas exergy efficiency ranged between 46.34% and 67.14%. Air heater exergy destruction was the highest, whereas exergy efficiency was the lowest at the highest steam system loads, which was an unexpected occurrence because the highest loads can be expected in the majority of marine steam plant operations. The change in the ambient temperature significantly influences steam air heater exergy efficiency. An increase in the ambient temperature of 10 °C reduces analyzed air heater exergy efficiency by 4.5%, or more, on average.

scholarly journals Energy and Exergy Analyses of Forced Draft Fan for Marine Steam Propulsion System during Load Change

2019 ◽  
Vol 7 (11) ◽  
pp. 381 ◽  
Author(s):  
Vedran Mrzljak ◽  
Paolo Blecich ◽  
Nikola Anđelić ◽  
Ivan Lorencin
Keyword(s):  
Ambient Temperature ◽  
Mass Flow ◽  
Entire Range ◽  
Exergy Efficiency ◽  
Exergy Destruction ◽  
Power Losses ◽  
Air Mass ◽  
Energy And Exergy ◽  
Forced Draft ◽  
Steam System

A forced draft fan, used for the supply of combustion air into the steam generator of the conventional liquefied natural gas (LNG) carrier was analyzed from the aspect of energy and exergy. The power delivered from the induction motor to the fan was calculated using the manufacturer’s data. The most significant impact on the fan energy power losses is from the air temperature difference between the fan outlet and inlet. The fan energy power losses are inversely proportional to the fan energy efficiency, and the values are between 19.9% and 63.4%, for the entire range of observed steam system loads. The fan exergy destruction depends primarily on the driving power and on the air mass flow rate. At higher loads, an important influence on the fan exergy destruction is from the air pressure at the fan outlet. The exergy efficiency change of the analyzed fan, for the range of observed steam system loads, is directly proportional to the rate of change in the air mass flow, whereas the obtained values of exergy efficiency are between 5.10% and 53.93%. The impact of ambient temperature on the fan exergy destruction and exergy efficiency exhibits is different than in most other steam system components. A change in ambient temperature of 10 °C causes a change in the exergy efficiency of the forced draft fan less than 0.5% in the entire range of observed steam loads.

scholarly journals 4E Analysis of a Fuel Cell and Gas Turbine Hybrid Energy System

2020 ◽  
Vol 11 (1) ◽  
pp. 7568-7579
Keyword(s):  
Fuel Cell ◽  
Cell Voltage ◽  
Energy System ◽  
High Energy ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Net Energy ◽  
Exergy Destruction ◽  
Molten Carbonate ◽  
Ambient Temperatures

Exergy analysis of the expansion turbine hybrid cycle of integrated molten carbonate fuel cells is presented in this study. The proposed cycle was used as a sustainable energy curriculum to provide a small hybrid power plant with high energy efficiency. To generate electricity with the system mentioned above, and externally repaired fusion carbon fuel cell was used located at the top of the combined cycle. Moreover, the turbine and steam turbine systems are considered as complementary and bottom layers for co-generation, respectively. The results showed that the proposed system could reach net energy of up to 1125 kilowatts, while the total exergy efficiency (including electricity and heat) for this system is more than 68%. Moreover, the energy supplied and exergy efficiency derived from the proposed cycle are stable versus changes in ambient temperatures. Besides, the effect of increasing the current density on the cell voltage and the total exergy destruction was considered. Also, the new approaches of the exergoeconomics and exergoenvironmental analysis are implemented in this system. The results show that the hybrid system can decrease the exergy destruction costs more than 16%, and the environmental footprint of the system more than 23.4%.

scholarly journals Development of Technology for Production of Coal-Water Fuel and Determination of the Optimality of Its Combustion

2021 ◽  
Vol 7 (6) ◽  
Author(s):  
N. Aldasheva
Keyword(s):  
Power Plants ◽  
Oil And Gas ◽  
Low Cost ◽  
High Energy ◽  
Fuel Oil ◽  
Energy Potential ◽  
Environmental Friendliness ◽  
Wide Range ◽  
Organic Fuels ◽  
Simple Technology

The article investigates the processes of preparing liquid fuel based on a mixture of coal from the Alai deposit (Kyrgyzstan) and water with the addition of other components, for combustion in various power plants and intended to replace organic fuels (solid fuel, fuel oil and gas). On the basis of the research results, a technological scheme for the preparation of coal-water fuel from the organic matter of the Alai deposit has been developed. Methods and technologies for the preparation of coal-water fuel are described. As a result, an efficient and energy-efficient method for producing coal-water fuel has been developed, which has a high energy potential, environmental friendliness, low cost, a wide range of applications and a fairly simple technology for its implementation.

scholarly journals Selecting the Optimal Use of the Geothermal Energy Produced with a Deep Borehole Heat Exchanger: Exergy Performance

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 20
Author(s):  
Claudio Alimonti ◽  
Paolo Conti ◽  
Elena Soldo
Keyword(s):  
Heat Exchanger ◽  
Geothermal Energy ◽  
District Heating ◽  
High Energy ◽  
Exergy Efficiency ◽  
Deep Borehole ◽  
Borehole Heat Exchanger ◽  
Cascade System ◽  
Wide Range ◽  
Well Depth

The geothermal sector has a strength point with respect to other renewable energy sources: the availability of a wide range of both thermal and power applications depending on the source temperature. Several researches have been focused on the possibility to produce geothermal energy without brine extraction, by means of a deep borehole heat exchanger. This solution may be the key to increase the social acceptance, to reduce the environmental impact of geothermal projects, and to exploit unconventional geothermal systems, where the extraction of brine is technically complex. In this work, exergy efficiency has been used to investigate the best utilization strategy downstream of the deep borehole heat exchanger. Five configurations have been analyzed: a district heating plant, an absorption cooling plant, an organic Rankine cycle, a cascade system composed of district heat and absorption chiller, and a cascade system composed of the organic Rankine plant. District heating results in a promising and robust solution: it ensures high energy capacities per well depth and high exergy efficiency. Power production shows performances in line with typical geothermal binary plants, but the system capacity per well depth is low and the complexity increases both irreversibilities and sensibility to operative and source conditions.

Kajian Eksergi Pembangkit Listrik Tenaga Gas (Studi Kasus di PT. Indonesia Power Up Perak-Grati)

2019 ◽  
Vol 17 (3) ◽  
Author(s):  
Putri Sundari ◽  
Bayu Rudiyanto ◽  
Budi Hariyono
Keyword(s):  
Ambient Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Exergy Efficiency ◽  
Large Temperature ◽  
Exergy Destruction ◽  
Compressor Inlet ◽  
Energy And Exergy Analysis ◽  
Physical And Chemical ◽  
Gas Turbine Power Plant

This research discusses an energy and exergy analysis of a 112,45 MW gas turbine power generation system. The exergy of a material stream is divided into physical and chemical exergyand evaluated on each state. The results of this study reveal that the highest exergy destruction occurs in combustion chamber (65,81%), where the large temperature difference is the major source of the irreversibility. The exergy destruction in turbine gas and compressor was found 26,62% and 7,57% respectively. The effect of various gas turbine load and ambient temperature to the system’s performance were also studied. The result shows that increasing gas turbine loadgives positif effecton the exergy efficiency of the cycle as well as the components compressor and combustion chamber. Increasing ambient temperature givesnegatif effect, bywhich exergy efficiency of cycle was decreasing. Accordingly, cooling of the compressor inlet air is considered as the solution to this problem.Penelitian ini membahas analisis energi dan eksergi pada sistem pembangkit listrik tenaga gas berkapasitas 112,45 MW. Laju aliran eksergi dibagi menjadi dua komponen yaitu eksergi fisik dan eksergi kimia yang dievaluasi pada masing-masing keadaan. Hasil dari penelitian ini menunjukkan bahwa pemusnahan eksergi terbesar terjadi di ruang bakar (68,61%), dimana perbedaan temperatur yang besar merupakan sumber utama terjadinya irreversibilitas. Sedangkan pemusnahan eksergi pada turbin gas dan kompresor masing- masing sebesar 26,62% dan 7,57%. Pada penelitian ini juga membahas pengaruh dari tingkat pembebanan dan suhu udara lingkungan untuk mengetahui perubahan performa yang dihasilkan. Hasil dari variasi pembebanan menunjukkan bahwa peningkatan beban turbin gas berpengaruh positif terhadap efisiensi siklus maupun komponennya, yaitu kompresor dan ruang bakar. Peningkatan suhu udara lingkungan berdampak sebaliknya, dimana efisiensi siklus mengalami penurunan pada suhu udara lingkungan yang lebih tinggi. Sehingga untuk mengendalikan faktor tersebut dapat dilakukan dengan pendinginan suhu udara masuk kompresor.Keywords: energy, exergy, exergy efficiency, Gas Turbine Power Plant.

scholarly journals Exergy Analysis of 1 x 135 MW Jeneponto Steam Power Plant

2021 ◽  
Vol 7 (2) ◽  
pp. 150
Author(s):  
Nur Hamzah ◽  
A.M Shiddiq Yunus ◽  
Waqva Enno Al Fadiyah
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Second Law ◽  
Exergy Destruction ◽  
Steam Power ◽  
Total Destruction ◽  
Destruction Efficiency ◽  
Mass Flowrate

Exergy analysis is application of the second law thermodynamics which provides information about large exergy, exergy efficiency, destruction, and destruction efficiency in each component of PLTU so can be reference for improvement and optimization in an effort to reduce losses and increase efficiency. The exergy value obtained from calculating mass flowrate, enthalpy, ambient temperature, and entropy. The destruction value is obtained from difference between input exergy value and exergy output. The destruction exergy value from comparison between output exergy value to input exergy value, and destruction efficiency value from comparison of destruction value to total destruction value of PLTU components. The results showed that the largest exergy occurred in boilers, namely 778.225 MW in 2018, 788.824 MW in 2019, and 796.824 MW in 2020, lowest exergy value in CP was 0.160 MW in 2018, 0.176 MW in 2019, and 0.160 MW in 2020. The largest destruction occurred in boilers, namely 163.970 MW with destruction efficiency 79.242% in 2018, 179.450 MW with destruction efficiency 82.111% in 2019, and 199.637 MW with destruction efficiency 83.448% in 2020, lowest exergy destruction value at CP, namely 0.056 MW with destruction efficiency 0.027% in 2018, 0.059 MW with destruction efficiency 0.027% in 2019, and 0.056 MW with destruction efficiency 0.023% in 2020. The exergy efficiency occurred in HPH 2, amounting to 94.750% in 2018, 95.187 % in 2019, and 94.728% in 2020, while lowest of exergy efficiency was in LPH 1, namely 43.637 MW in 2018, 33.512 MW in 2019, and 38.764 MW in 2020.

Thermodynamic modeling and Exergy Analysis of Gas Turbine Cycle for Different Boundary conditions

2015 ◽  
Vol 6 (2) ◽  
pp. 205 ◽  
Author(s):  
Lalatendu Pattanayak
Keyword(s):  
Ambient Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Exergy Analysis ◽  
Load Condition ◽  
Exergy Efficiency ◽  
Inlet Temperature ◽  
Exergy Destruction ◽  
And Performance ◽  
Topping Cycle

In this study an exergy analysis of 88.71 MW 13D2 gas turbine (GT) topping cycle is carried out. Exergy analysis based on second law was applied to the gas cycle and individual components through a modeling approach. The analysis shows that the highest exergy destruction occurs in the combustion chamber (CC). In addition, the effects of the gas turbine load and performance variations with ambient temperature, compression ratio and turbine inlet temperature (TIT) are investigated to analyse the change in system behavior. The analysis shows that the gas turbine is significantly affected by the ambient temperature which leads to a decrease in power output. The results of the load variation of the gas turbine show that a reduction in gas turbine load results in a decrease in the exergy efficiency of the cycle as well as all the components. The compressor has the largest exergy efficiency of 92.84% compared to the other component of the GT and combustion chamber is the highest source of exergy destruction of 109.89 MW at 100 % load condition. With increase in ambient temperature both exergy destruction rate and exergy efficiency decreases.

Design Considerations and Operation of Condenser Bypass Systems in Combined Cycle Power Plants: Part 1

2004 ◽  
Author(s):  
Richard H. Eaton ◽  
Edward R. Blessman ◽  
Kevin G. Schoonover
Keyword(s):  
Power Plants ◽  
High Energy ◽  
Combined Cycle ◽  
Design Considerations ◽  
Turbine Condenser ◽  
Wide Range ◽  
Combined Cycle Plant ◽  
Steam Turbine Condenser ◽  
Functional Operation ◽  
And Control

As many Combined Cycle Power Plants have come into operation over the last 10 years, premature condenser tube failures have been experienced at several installations. This paper reviews factors and mechanisms contributing to such failures. The steam turbine condenser must operate under a demanding, wide range of conditions. Tubes within the condenser experience cyclic stresses, direct contact from admission of high-energy steam into the condenser, and the effects from a wide service range beginning with start-up and commissioning through continuous or intermittent daily operation. A number of factors go into properly designing condenser related sub-systems as required by the functional operation of the combined cycle plant. The condenser bypass system is a critical component directly affecting the operation, maintenance and control of conditions experienced by the condenser. Part 1 of this paper identifies related problems experienced, in the field, within the condenser considering operation and maintenance, and also provides design considerations to avoid occurrence of tube failures. Part 2 of this paper addresses many key points for consideration with respect to the design and implementation of the high-energy bypass system leading into the condenser.

scholarly journals Exergy Efficiency Promotion for the System of CO2 Hydrogenation to Methanol in Habitable Confined Space

2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Xiong ◽  
Yong-Li Yin ◽  
Yong Cao ◽  
Xiao-Tian Liu
Keyword(s):  
Carbon Dioxide ◽  
Energy Consumption ◽  
Working Condition ◽  
Space Velocity ◽  
High Energy ◽  
Exergy Efficiency ◽  
Total System ◽  
Exergy Destruction ◽  
Confined Space ◽  
External Energy

Excess hydrogen and carbon dioxide will be produced during the operation of life support systems in the habitable confined space (HCS), and to eliminate the two excess gases by converting them into methanol is of great significance for maintenance of atmospheric balance and protection of crew’s life safety. Due to the limited energy supply ability within the HCS, it is important for the system of carbon dioxide hydrogenation to methanol (CDHM) to operate with high energy efficiency to reduce unnecessary external energy consumption and internal energy loss. In this paper, the exergy analysis method is adopted for exergy efficiency improvement. Specifically, a parametric study on the exergetic performance of the CDHM system is conducted based on the three key working condition parameters that have a huge impact on the reaction process and energy utilization quality, which is used to find the favorable working condition with low external energy consumption and exergy destruction per unit gas elimination and high exergy efficiency. Within the chosen three reaction parameters which are reaction pressure, temperature, and space velocity ranging from 5 to 8 MPa, from 483.15 to 543.15 K, and from 2,800 to 4000 h−1, respectively, the gas elimination of carbon dioxide and hydrogen increases by 13.3, 19.58, and 30.58%, respectively. Moreover, the input power, cold energy consumption, and exergy destruction per molar synthetic methanol all grow to some extent, leading to a 0.06% decline, a 0.46% promotion, and a 0.15% decrease, respectively, in the exergy efficiency. The results show that the high exergy efficiency can be realized with relatively low pressure, high temperature, and low space velocity in the working condition. Besides, the exergy destructions of each component in the CDHM system are also presented in this paper. The exergy destructions in the methanol synthesis reactor, heater, and heat exchanger hot end are found to be the three biggest, whose summation accounts for more than 90% of the total system exergy destruction. Thus, the exergy efficiency also can be improved by reducing the three biggest exergy destructions.

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