scholarly journals Hydrodynamics and mass transfer deaeration of water on thermal power plants when used natural gas as a desorbing agent

2017 ◽  
Vol 891 ◽  
pp. 012102
Author(s):  
V I Sharapov ◽  
E V Kudryavtseva
Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by: 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are: 1) thermal - primary coal and secondary natural gas; 2) “large” hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that they are still the largest emitters of carbon dioxide into atmosphere. Due to that, reliable non-fossil-fuel energy generation, such as nuclear power, becomes more and more attractive. However, current Nuclear Power Plants (NPPs) are way behind by thermal efficiency (30–42%) compared to that of advanced thermal power plants. Therefore, it is important to consider various ways to enhance thermal efficiency of NPPs. The paper presents comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.


Akustika ◽  
2021 ◽  
pp. 133-137
Author(s):  
Vladimir Tupov ◽  
Vitaliy Skvortsov

The power equipment of thermal power plants is a source of noise to the surrounding area. One of the sources of noise for the surrounding area are gas distribution points (GDP) of thermal power plants (TPP) and district thermal power plants (RTS). Noise from gas distribution points may exceed sanitary standards at the border of the sanitary protection zone. The article shows that the radiated noise from gas distribution points depends on the power of the thermal power plant (natural gas consumption) and the type of valves. Three types of valves used in gas distribution points are considered. Formulas are obtained for calculating the width of the sanitary protection zone for gas distribution points for thermal stations, depending on the consumption of natural gas (electric power of the thermal power plant) and the type of valve. It is shown that, depending on the valve used, the noise level at the border of the sanitary protection zone can either meet sanitary standards or exceed them. This allows at the design stage to select the required type of valve or to determine mitigation measures from hydraulic fracturing.


Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa ◽  
Luiz Augusto Horta Nogueira ◽  
Electo E. Silva Lora

The operational rules for the electricity markets in Latin America are changing at the same time that the electricity power plants are being subjected to stronger environmental restrictions, fierce competition and free market rules. This is forcing the conventional power plants owners to evaluate the operation of their power plants. Those thermal power plants were built between the 1960’s and the 1990’s. They are old and inefficient, therefore generating expensive electricity and polluting the environment. This study presents the repowering of thermal power plants based on the analysis of three basic concepts: the thermal configuration of the different technological solutions, the costs of the generated electricity and the environmental impact produced by the decrease of the pollutants generated during the electricity production. The case study for the present paper is an Ecuadorian 73 MWe power output steam power plant erected at the end of the 1970’s and has been operating continuously for over 30 years. Six repowering options are studied, focusing the increase of the installed capacity and thermal efficiency on the baseline case. Numerical simulations the seven thermal power plants are evaluated as follows: A. Modified Rankine cycle (73 MWe) with superheating and regeneration, one conventional boiler burning fuel oil and one old steam turbine. B. Fully-fired combined cycle (240 MWe) with two gas turbines burning natural gas, one recuperative boiler and one old steam turbine. C. Fully-fired combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. D. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. The gas turbine has water injection in the combustion chamber. E. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners and one old steam turbine. The gas turbine has steam injection in the combustion chamber. F. Hybrid combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners, one old steam boiler burning natural gas and one old steam turbine. G. Hybrid combined cycle (235 MWe) with one gas turbine burning diesel fuel, one recuperative boiler with supplementary burners, one old steam boiler burning fuel oil and one old steam turbine. All the repowering models show higher efficiency when compared with the Rankine cycle [2, 5]. The thermal cycle efficiency is improved from 28% to 50%. The generated electricity costs are reduced to about 50% when the old power plant is converted to a combined cycle one. When a Rankine cycle power plant burning fuel oil is modified to combined cycle burning natural gas, the CO2 specific emissions by kWh are reduced by about 40%. It is concluded that upgrading older thermal power plants is often a cost-effective method for increasing the power output, improving efficiency and reducing emissions [2, 7].


2019 ◽  
Vol 124 ◽  
pp. 05065
Author(s):  
M.A. Taymarov ◽  
R.V. Akhmetova ◽  
Ye.G. Chiklyayev ◽  
Y.V. Lavirko ◽  
E.A. Akhmetov ◽  
...  

At present, natural gas of the Urengoyskoye field is burned in boilers of thermal power plants (TPP) to generate electricity. At the same time, refineries and petrochemical plants deepen the processing of fossil liquid hydrocarbons. The final product of processing is not only motor fuels, ethylene glycols, plastics, accompanying inert gases such as argon, but also a large amount of combustible secondary gaseous mixtures of the methane series. These mixtures contain a wide array of combustible components. Among them there is the methane-hydrogen fraction, which is characterized by a fairly high hydrogen content. A distinctive feature of the use of hydrogen as a fuel is the high rate of flame propagation and the relatively low heat of combustion [1, p.6-8]. The methane-hydrogen fraction due to the volatility of the composition and a wide range of changes in the heat of combustion was recently used in refineries for their own needs as an insignificant additive to combusted natural gas in process furnaces [2-5]. If the methane-hydrogen fraction was not utilized as a fuel in these furnaces, it was burned in flares. Due to the increase in oil refining volumes and the increase in the amount of methane-hydrogen fraction produced, it became realistic to use this gaseous fraction as the main fuel for power boilers of thermal power plants located near petrochemical plants. In the near future, it is planned to use the methane-hydrogen fraction as an additive to the natural gas for 20 power steam boilers of the Nizhnekamsk CHP-1 with a total thermal capacity of 6000 MW. The supplier of the methane-hydrogen fraction is the TAIF NK oil refineries. Depending on the technology of oil refining, the hydrogen content in the methane-hydrogen fraction ranges from 10 to 27% (by weight). The concentration limits of hydrogen ignition in a mixture with air have been experimentally studied by many researchers [6–8] mainly during bench testing or inside laboratories. A feature of the oxidation of hydrogen by air oxygen is the fact that there is a difference between the spread of the flame in limited volumes and in large volumes of the furnace space of energy boilers [9]. In small volumes, when the flame front collides with the wall, oxidation reactions are interrupted, and this does not occur in large volumes. Therefore, the study of flame propagation speed and concentration limits of ignition of methanehydrogen fractions mixed with air in relation to the conditions of furnace volumes of power boilers is relevant. In this work using the in-house software [2-5] calculations were made to determine the burning rate for various compositions of mixtures of methane-hydrogen fractions (MHF) with Urengoi natural gas. It was found that the flame propagation rate of the MHF, compared with hydrogen (see Table 2), decreases 1.76 times. For a mixture of the MHF with Urengoi gas with thermal fractions of the MHF of 12% and 25%, the flame propagation rate increases, respectively, 1.4 times and 1.78 times compared with burning pure Urengoi gas.


Author(s):  
Cássio Florisbal de Almeida ◽  
Vinícius Gonçalves Maciel ◽  
Luiz Fernando de Abreu Cybis

O setor energético é de suma importância para o crescimento estratégico de qualquer país. Isso não é diferente no Brasil, o qual apresenta uma matriz energética diversificada, mas que tem um predomínio do setor hidrelétrico. No entanto, o setor termelétrico tem crescido nos últimos anos para garantir a segurança energética e, nos sistemas isolados, a termeletricidade é predominante. Este é o caso do estado do Amazonas, o qual recebe energia prioritariamente de usinas termelétricas da região. As usinas da região utilizam, em sua maioria, combustíveis fósseis tais como diesel, óleo combustível pesado (HFO, em inglês). Atualmente, tem sido incorporada a este sistema a utilização do gás natural proveniente da bacia petrolífera amazônica, localizada em Urucu. Nesse sentido, para analisar a influência ambiental desta mudança nas usinas termelétricas, este emprega a metodologia de Avaliação do Ciclo de Vida (ACV) da eletricidade entregue ao grid por uma usina termelétrica, localizada em Manaus, que utiliza óleo combustível pesado e gás natural como combustível. O estudo foi conduzido do berço ao portão da usina a partir de dados primários da própria usina e dados secundários de bibliografia da área. Para a observação das diferenças, fez-se um estudo comparativo entre a mesma usina em duas situações: utilizando somente óleo combustível pesado e o uso concomitante deste combustível com o gás natural. A Avaliação do Impacto de Ciclo de Vida foi calculada pelo método CML IA baseline com o uso do software SimaPro e escolheu-se a categoria de impacto de Aquecimento Global para análise. A conversão bicombustível resultou em redução do impacto da usina, que antes era de 590,50 kg CO2eq/MWh e passou para 521,11 CO2eq/MWh, no entanto ao longo do ciclo de vida o resultado se manteve no mesmo patamar. Resumen El sector energético es de suma importancia para el crecimiento estratégico de cualquier país. Esto no es diferente en Brasil, que tiene una matriz energética diversificada, pero que tiene un predominio del sector hidroeléctrico. Sin embargo, el sector termoeléctrico ha crecido en los últimos años para garantizar la seguridad energética y, en sistemas aislados, termoelectricidad es predominante. Este es el caso de estado del Amazonas, que recibe energía principalmente de centrales térmicas de energía en la región. Las plantas de la región utilizan, sobre todo, combustibles fósiles como el diesel, fuelóleo pesado (HFO en inglés). En la actualidad, se ha incorporado a este sistema, el uso de gas natural de la cuenca petrolífera del Amazonas, situado en Urucu. En este sentido, para analizar el impacto ambiental de este cambio en las centrales térmicas, este estudio emplea la metodología del Análisis de Ciclo de Vida (ACV) de la electricidad entregada a la red por una central térmica, que se encuentra en Manaus, que utiliza fuelóleo pesado y gas natural como combustibles. El estudio se realizó a partir de datos primarios de la central térmica y datos secundarios de literatura del área. Para observar las diferencias, se hizo un estudio comparativo de la misma planta en dos situaciones: utilizando sólo el fuelóleo pesado y el uso concomitante de este combustible con gas natural. La evaluación del impacto del ciclo de vida se calculó por el método de CML IA baseline usando el software SimaPro y optó por categoría de impacto del calentamiento global para análisis. La conversión bi-combustible resultó en una redución del impacto de la planta, que antes era de 590.50 kg CO2eq / MWh y aumentó a 521.11 CO2eq / MWh. Sin embargo a lo largo del ciclo de vida, el resultado se mantuvo en el mismo nivel. Abstract The electric sector is very important to the strategic growing of any country. It isn’t different in Brazil, which shows a diversified energy matrix, but has a predominance of hydropower sector. However, the thermoelectric sector has grown in the last years to guarantee the electrical safety and, in isolated systems, the thermoelectricity is predominant. It is the case of Amazonas State, which receives energy priority from thermal power plants in the region. They use, mostly, fossil fuels such as Diesel, Heavy Fuel Oil (HFO). Nowadays, it has been incorporated into this system the natural gas use from Amazon oil basin, located in Urucu. In this sense, to analyze the environmental influence of this change on the thermal power plants, this study intends to employ the methodology of Life Cycle Assessment (LCA) of the electricity delivered to the grid by one thermal power plant (TPP), located in Manaus, which uses HFO and Natural Gas as fuel. For observation of differences, it was performed a comparative study of this power plant in two situations: using only HFO and using HFO and Natural gas concomitant. The study was conducted from cradle to gate of the power plant from specific primary data, provided by the power plant and secondary data from the literature. The Life Cycle Impact Assessment (LCIA) was calculated from the CML IA baseline with the use of SimaPro software and it was chosen the impact category of Global Warming Potential (GWP) for analysis. The conversion bifuel resulted in reduction of the impact of the TPP, which previously was 590.50 kg CO2eq / MWh and passed to 521.11 CO2eq / MWh. However, the bifuel power plant has, along the lifecycle, when compared the operation with only HFO, the same magnitude of GWP due to contributions of, for example, natural gas production.


Sign in / Sign up

Export Citation Format

Share Document