scholarly journals Investigating the Effects of Parametric Variation over Performance of Boiler-Turbine Cycle

2021 ◽  
Vol 9 (8) ◽  
pp. 2620-2628
Author(s):  
Dr. S. S. L. Patel
Keyword(s):  
Adverse Effect ◽  
Energy Efficiency ◽  
Energy Loss ◽  
Ambient Temperature ◽  
Flue Gas ◽  
Environmental Temperature ◽  
Exergy Efficiency ◽  
Plant Performance ◽  
Second Law ◽  
Gas Temperature

Abstract: In this paper, the effects of variation in ambient temperature, flue gas temperature and condenser pressure over performance of boiler and turbine cycle is presented. The study is carried out with EES software. The change in ambient temperature is seriously deteriorating the boiler exergetic performance as its exergy efficiency reduces by 2.5% with increase in environmental temperature from 27C to 45C while the boiler total energy loss reduces almost 1% for same increase in ambient temperature. The turbine second law efficiency is affected slightly by ambient temperature. Increase in temperature of exhaust flue gas has adverse effect over boiler energy efficiency, which reduces by almost 1% with flue gas temperature variation from 110C to 130C. The increase in condenser pressure is reducing the turbine energy efficiency to more than 3% with variation from 0.05bar to 0.3bar. Condenser exergy efficiency is decreasing sharply with increase in its pressure. The effect of variation in condenser pressure over net output of the boiler-turbine cycle has also been studied and it is found to be decreasing with increase in condenser pressure. Keyword: Ambient temperature, Boiler-turbine cycle, Condenser pressure, Flue gas, Plant performance.

NOx process inhibition and energy efficiency improvement in new swirl modification device for steel slag based on coal combustion

2018 ◽  
Vol 16 (7) ◽  
Author(s):  
Junxiang Guo ◽  
Lingling Zhang ◽  
Daqiang Cang ◽  
Liying Qi ◽  
Wenbin Dai ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Flue Gas ◽  
Coal Combustion ◽  
Steel Slag ◽  
Coal Ash ◽  
Combustion Efficiency ◽  
Gas Temperature ◽  
Staged Combustion ◽  
Energy Efficiency Improvement ◽  
Swirl Combustion

Abstract In this study, a novel swirl combustion modified device for steel slag was designed and enhanced with the objective of achieving highly efficient and clean coal combustion and also for achieving the whole elements utilization of coal. Coal ash and steel slag were melted in the combustion chamber and subsequently entered the slag chamber. The detrimental substances solidified and formed crystals, which allowed for the comprehensive utilization of the ash and slag. Our experiments mainly aimed to mitigate the formation of NOx, while using the heat and slag simultaneously during the coal combustion without a combustion efficiency penalty. The increase in the device’s energy efficiency and reduction in the NOx emissions are important requirements for industrialization. The experiments were carried out in an optimized swirling combustion device, which had a different structure and various coal feeding conditions in comparison to previously reported devices. The fuel-staged and non-staged combustion experiments were compared under different coal ratios (bitumite:anthracite). For the fuel-staged combustion experiments, the NOx concentration in the flue gas was observed to decrease significantly when the coal ratio of 1:1, an excess air coefficient of 1.2, and a fuel-staged ratio of 15:85 were used. Under these conditions, the flue gas temperature was as high as 1,620°C, while the NOx concentration was as low as 320 mg/m3 at 6 % O2. The air-surrounding-fuel structure that formed in the furnace was very beneficial in reducing the formation of NOx. In comparison to other types of coal burners, the experimental combustion device designed in this study achieved a significant reduction of NOx emissions (approximately 80 %).

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.

scholarly journals Application of the Second Law of Thermodynamics in Brazilian Residential Appliances towards a Rational Use of Energy

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 616 ◽  
Author(s):  
Carlos Eduardo Keutenedjian Mady ◽  
Clara Reis Pinto ◽  
Marina Torelli Reis Martins Pereira
Keyword(s):  
Energy Efficiency ◽  
Natural Resources ◽  
Air Conditioning ◽  
Second Law Of Thermodynamics ◽  
Exergy Efficiency ◽  
Second Law ◽  
Vapor Compression ◽  
Energy Matrix ◽  
Additional Information

This article proposes the utilization of the concepts of destroyed exergy and exergy efficiency for equipment and process performance indicators that are related to the current energy planning scenario in Brazil, more specifically with energy-efficiency labelling. Several indicators associated with these concepts are discussed, including one national program that is based on labeling the energy efficiency of several residential, commercial and industrial appliances. The grades are indicated in the equipment using values from A to G. This labeling system is useful for discriminating similar technologies used for the same function; nevertheless produced by different enterprises. For this complementary analysis, two types of refrigeration methods were compared, absorption and vapor compression; however, these energy indexes alone are not sufficient parameters to select among these two technologies, because their performance indexes definition are different. To address this, our research considers the second law of thermodynamics through exergy analysis as a proper sub-index to obtain a systematic comparison between these various indicators. It is significant to highlight that seldom research studies addressed to this problem so explicitly, in an actual governmental working solution, aiming at discussing to the society the advantage of the usage of the “quality of the energy” as a complementary index to governmental and personal choices. Results indicate that it is possible to use the destroyed exergy and exergy efficiency to help select the technology that better utilizes natural resources, considering the energy matrix of the country. Appliances for water heating and air conditioning were compared from energy and exergy viewpoint, where the last gave additional information about the quality of energy conversion process, giving a completely different trend from the energy analysis alone, without the necessity to think about the energy matrix. Later this issue is addressed from both points of view. Future studies may suggest an exergy based index. The energy efficiency suggests that electrical shower (values higher than 95%) are better than gas water heaters (83% ) in using natural resources, whereas the exergy efficiency shares similar magnitudes (about 3%). A related pattern is shown for the theoretical air conditioning systems. The vapor compression systems have an energy index higher than 3, and absorption systems lower than 1. For these circumstances, the exergy efficiency shows figures nearby 30%.

scholarly journals Exergy Analysis of Waste Incineration Plant: Flue Gas Recirculation and Process Optimization

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 29
Author(s):  
Giorgio Vilardi ◽  
Nicola Verdone
Keyword(s):  
Flow Rate ◽  
Flue Gas ◽  
Gas Flow ◽  
Exergy Analysis ◽  
Waste Incineration ◽  
Exergy Efficiency ◽  
Gas Temperature ◽  
Gas Flow Rate ◽  
Flue Gas Recirculation ◽  
Gas Recirculation

Simulations of two incineration processes, with and without flue gas recirculation, have been carried out performing an exergy analysis to investigate the most critical equipment unit in terms of second-law efficiency. Flue gas from the economizer outlet is employed to partially replace secondary combustion air to reduce, at the same time, incinerator temperature and oxygen concentration. Conversely, in the proposed configuration, the recirculated flue gas flow rate is used to control incinerator temperature, while the air flow rate is used to control the oxygen content of the fumes, leaving the incinerator as close to 6% as possible—i.e., the minimum allowed for existing plants to ensure completion of the combustion reactions and according to environmental regulations—and determines the corresponding minimum flue gas flow rate. The flue gas recirculation guarantees a larger level of energy recovery (up to +3%) and, at the same time, lower investment costs for the lower flow rate of fumes actually emitted if compared to the plant configuration without flue gas recirculation. Various operating parameters were varied (incinerator’s effluent gas temperature, air flowrate and flue gas recirculation flowrate) to investigate their influence on process exergy efficiency. Exergy analysis allowed the individuation of the equipment units characterized by larger exergy destruction and demonstrated that the flue gas recirculation led to an overall process exergy efficiency increase of about 3%.

scholarly journals An energy and exergy analysis of photovoltaic system in Bantul Regency, Indonesia

2018 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Arif Rahman Hakim ◽  
Wahyu Tri Handoyo ◽  
Putri Wullandari
Keyword(s):  
Energy Efficiency ◽  
Exergy Analysis ◽  
Environmental Temperature ◽  
Exergy Efficiency ◽  
Photovoltaic System ◽  
Pv System ◽  
High Solar Radiation ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Special Region

Energy and exergy analysis has been conducted on photovoltaic (PV) system in Bantul Regency, a special region of Yogyakarta, Indonesia. The PV exergy analysis was used to determine the performance of the PV system by considering environmental factors other than solar irradiance. This research aims to obtain values of exergy and energy efficiencies in the PV system. The experiment results show that the energy efficiency value produced by the PV system was 8.62–74.18%, meanwhile its exergy efficiency was 0.29%-9.40%, respectively. The value of exergy efficiency is lower than the value of energy efficiency. This result confirmed that the environmental factor greatly affects the output of the PV system. It can be concluded that high solar radiation does not always increase the production of exergy, since it is also influenced by the environmental temperature and the PV cells' temperature.

Boosting Gas Processing Energy Efficiency by Waste Heat Recovery

2021 ◽  
Author(s):  
Waneya Abdulla Al Ketbi ◽  
Saqib Sajjad ◽  
Eisa Salem Al Jenaibi
Keyword(s):  
Energy Efficiency ◽  
Feasibility Study ◽  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Dew Point ◽  
Gas Temperature ◽  
Gas Processing ◽  
Sulphur Recovery

Abstract A continual improvement in energy efficiency of existing plants is imperative to achieve ADNOC target to reduce greenhouse gas emissions (GHG) intensity of operations by 25% in year 2030. The waste heat recovery (WHR) from incinerator stacks of existing Sulphur Recovery Units (SRUs) in ADNOC Gas Processing exhibits a substantial potential & contributor of energy savings and emission abatement. A high level assessment was carried out for various heat sources, results showed substantial WHR potential can be availed from SRUs. Consequently, a feasibility study was carried out to evaluate several options to recover energy from incinerator stacks of existing Sulphur Recovery Units (SRUs). The feasibility study addressed three options of recovering energy from SRUs incinerator stack exhaust; generating saturated steam, generating power and combined solution of steam & power. Those options were assessed in terms of technical feasibility and commercial viability. The study indicated that steam generation by HRSGs is technically viable and economically feasible, and considered as the best option for WHR from the existing SRU Incinerator Stacks. The WHR benefits that can be realized from just one incinerator stack by recovering the waste heat and reducing the flue gas temperature by 400 °C only (from 700 to 300 °C) are: More than 80 TPH saturated HP steam generationFuel gas savings and corresponding monetary benefitsSignificant abatement in GHG emissions The study revealed that WHR does not pose acid condensation risk due to the safe margin between the acid dew point and the actual flue gas temperature. The study also established that other constraints like pressure drop, space, tie-in location and emissions dispersion are not the showstoppers.

Thermal Performance of Biomass-Fired Steam Power Plant

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Chaouki Ghenai ◽  
Ahmed Amine Hachicha
Keyword(s):  
Power Plant ◽  
Flue Gas ◽  
Electrical Power ◽  
Heat Rate ◽  
Plant Performance ◽  
Energy Output ◽  
Gas Temperature ◽  
Forest Residues ◽  
Steam Power ◽  
Steam Power Plant

This paper presents results on the performance of 10 MW biomass-fired steam power plant. The main objective is to test the performance of the power plant using different type of biomass fuels: bagasse, corn stover, forest residues, and urban wood residues. The biomass fuel was mixed with sub-bituminous coal with fractions of 0–100%. The effect of excess combustion air, flue gas temperature, and the parasitic loads on the power plant performance was investigated. The output results from the heat and mass balance analysis include the monthly and annual electrical power generated, capacity factor (CF), boiler efficiency (BE), thermal efficiency, and gross and net heat rate. The results show a slightly decrease (1.7%) of the annual energy production when the biomass fractions increase from 6% to 100% but a substantial decrease of the CO2 equivalent emissions. A decrease of the excess combustion air from 25% to 5% will increase the boiler and thermal efficiencies and the annual energy output by 2%. This is mainly due to the reduction of the dry flue gas losses (DFGLs) with the reduction of the excess combustion air. A reduction of the parasitic loads from 10% to 2% will increase the power plant performance by 9%. This can be achieved by using more efficient pumps, fans, and conveyors in the power plant. A reduction of the flue gas temperature from 480 °F to 360 °F increases the power plant performance by 4.4% due to the reduction of the dry flue gas losses.

scholarly journals Analysis of Operation Parameters of Fish Refrigeration by Exergy Analysis. Case Study

2019 ◽  
Vol 23 (1) ◽  
pp. 229-241
Author(s):  
Edvins Terehovics ◽  
Ivars Veidenbergs ◽  
Dagnija Blumberga
Keyword(s):  
Energy Efficiency ◽  
Ambient Temperature ◽  
Working Conditions ◽  
Temperature Difference ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Single Stage ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
The Ideal

Abstract Unlike energy efficiency, in terms of exergy efficiency it is possible to compare the existing operation of an energy conversion system with the ideal operation. Exergy loses and exergy destruction make it possible to identify the shortcomings of an existing system, which should be improved immediately. With exergy analysis, it is possible to identify the priority actions that need to be taken in order to improve the functioning of the system: greater exergy loss prevention is the highest priority. Energy efficiency refers to the useful work and investments needed to obtain useful work and investments needed to obtain energy efficiency; this is important to some extent, but the effectiveness of exergy makes it possible to compare system performance with the ideal. Results shows that the highest exergy destruction of a single-stage compressor refrigeration system from all working condition is found when ambient temperature and freezer temperature difference is 10 ºC, pressure in compressor is 0.62 MPa, ammonia temperature after compressor is 90 ºC, total exergy destruction of single-stage compressor refrigeration system 97.84 kW. The highest exergy efficiency of a single-stage compressor refrigeration system from all the working conditions is found when ambient temperature and freezer temperature difference is 39 ºC, pressure in compressor is 0.45 MPa, ammonia temperature after compressor is 128 ºC, exergy efficiency of a single-stage compressor refrigeration system is 59.76 %. The highest total exergy destruction of a two-stage compressor refrigeration system from among all the working conditions is found to be when the ambient temperature and freezer temperature difference is at 13 ºC, pressure in compressor 0.44 MPa, ammonia temperature after compressor 76 ºC, total exergy destruction 83.86 kW. The highest exergy efficiency of a two-stage compressor refrigeration system from among all the working conditions is found to be at an ambient temperature and freezer temperature difference of 39 ºC, pressure in compressor 0.56 MPa, ammonia temperature after compressor 92 ºC, exergy efficiency 53.55 %.

On the Effects of Syngas Clean-Up Temperature in IGCCs

2010 ◽  
Author(s):  
Antonio Giuffrida ◽  
Matteo C. Romano
Keyword(s):  
Particulate Matter ◽  
Power Plant ◽  
Ambient Temperature ◽  
Thermodynamic Analysis ◽  
Regenerative Process ◽  
Plant Performance ◽  
Second Law ◽  
Trace Contaminants ◽  
Second Law Analysis ◽  
Limited Sensitivity

This paper deals with the thermodynamic analysis of an IGCC power plant with hot syngas clean-up, where sulfur, particulate matter and trace contaminants are removed without cooling the syngas down to near-ambient temperature. With particular attention to the simulation of the desulfurization unit, adopting a regenerative process using a ZnO-based sorbent, a range of clean-up temperatures was investigated in order to evaluate its effects on overall plant performance. The study reveals the attractive chance of achieving overall electric efficiencies around 50%. However, a limited sensitivity of IGCC efficiency on desulfurization temperature was also obtained, since no significant improvements were accomplished for temperatures over 400°C. In order to support and better understand the results, a second law analysis was also carried out for the assessed cases. In addition, the effects of syngas clean-up temperature on the design and operation of the main IGCC processes and components, which can be relevant, were discussed.

scholarly journals Low-Cost Organic Adsorbents for Elemental Mercury Removal from Lignite Flue Gas

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2174
Author(s):  
Marta Marczak-Grzesik ◽  
Stanisław Budzyń ◽  
Barbara Tora ◽  
Szymon Szufa ◽  
Krzysztof Kogut ◽  
...  
Keyword(s):  
Flue Gas ◽  
Low Cost ◽  
Elemental Mercury ◽  
Mercury Content ◽  
Flue Gases ◽  
Mercury Removal ◽  
Gas Purification ◽  
Gas Temperature ◽  
Corn Straw ◽  
Flue Gas Purification

The research presented by the authors in this paper focused on understanding the behavior of mercury during coal combustion and flue gas purification operations. The goal was to determine the flue gas temperature on the mercury emissions limits for the combustion of lignites in the energy sector. The authors examined the process of sorption of mercury from flue gases using fine-grained organic materials. The main objectives of this study were to recommend a low-cost organic adsorbent such as coke dust (CD), corn straw char (CS-400), brominated corn straw char (CS-400-Br), rubber char (RC-600) or granulated rubber char (GRC-600) to efficiently substitute expensive dust-sized activated carbon. The study covered combustion of lignite from a Polish field. The experiment was conducted at temperatures reflecting conditions inside a flue gas purification installation. One of the tested sorbents—tire-derived rubber char that was obtained by pyrolysis—exhibited good potential for Hg0 into Hg2+ oxidation, resulting in enhanced mercury removal from the flue. The char characterization increased elevated bromine content (mercury oxidizing agent) in comparison to the other selected adsorbents. This paper presents the results of laboratory tests of mercury sorption from the flue gases at temperatures of 95, 125, 155 and 185 °C. The average mercury content in Polish lignite was 465 μg·kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 17.8 µg·m−3. The study analyzed five low-cost sorbents with the average achieved efficiency of mercury removal from 18.3% to 96.1% for lignite combustion depending on the flue gas temperature.

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