Comparison and Analysis for the Differential Heating Modes in the Large-Scale CHP System

Author(s):  
Zhen Xian Lin ◽  
Lin Fu

With the process acceleration of China’s energy conservation and the full development of the market economy, the environmental protection is to coexist with the power plants’ benefits for thermal power plants. Relative to the traditional mode named “determining power by heat”, it is not adequate that the heating demand is only to be met, the maximizations of economy benefits and social benefits are also demanded. At present, several large-scale central heating modes are proposed by domestic and foreign scholars, such as the parallel arrangement and series arrangement of heating system for the traditional heating units and NCB heating units (NCB heating unit is a new condensing-extraction-backpressure steam turbine and used to generate the power and heat, it has the function of extraction heating turbine at constant power, back pressure turbine or extraction and back pressure heating turbine and extraction condensing heating turbine.), and running mode with heating units and absorbed heat pumps, and so on. Compare and analyze their heating efficiency, heating load, heating area, power generation, and the impact on the environment. The best heating mode can be found under the different boundary conditions, it can be used to instruct the further work. The energy utilization efficiency will be further improved.

2021 ◽  
Author(s):  
Reza Bashiri Khuzestani ◽  
Ahmad Taheri ◽  
Bijan Yeganeh

Abstract Large-scale emissions of sulfur dioxide (SO2) from the combustion of heavy fuel oils are deteriorating the air quality in Tehran and regularly causing complex atmospheric pollution situations and human health concerns. Our analysis of the long-term SO2 emission data in Tehran confirmed that the magnitude of local SO2 emission sources is not adequate to reach SO2 concentrations to their present levels. Tehran is predominantly affected by regional transport of SO2 from exterior sources further away located in Iraq, Saudi Arabia, and adjacent provinces neighboring Tehran. Approximately 80% of total SO2 emissions in Tehran were observed to have impacts from the external hotspots outside of Tehran. While local emission sources only contribute around 20% of the total SO2 emissions. Bivariate polar plots, k-mean cluster, pairwise polar correlation, and PSCF analysis provided evidence for the impact of large-scale transport of SO2 emissions from external locations from the west/northwest, north/northeast, and south/southwestern areas of the region. Further observations of these hotspot areas observed in our analysis with TROPOMI satellite data confirmed significant SO2 emissions resulting from the consumption of heavy fuel oils in thermal power plants and oil/gas refineries. Overall, the results suggested that the regulatory strategies for controlling local traffic emissions of SO2 in Tehran would not be beneficial for reducing public health exposures to SO2 in Tehran. Such improvements can be attained mainly by diminishing the emission sources located further away from Tehran.


2014 ◽  
Vol 1070-1072 ◽  
pp. 275-278
Author(s):  
Li Lin ◽  
Shuang Zhao ◽  
Meng Ze Yu ◽  
Bo Jian Ding

As wind is random, intermittent and instability, with continual installation of wind farms, the impact of large scale wind farm on power system has become an important issue for integration and operation of wind farm. Aiming at studying the transient stability of district grid containing high proportion of wind power, numerical simulations with BPA for an actual district grid of China Southern Power Grid are presented. In these simulations, the interaction between the large-scale wind farm and traditional thermal power plants (TPPs) is investigated taking the different operating modes and fault location into account. The critical clearing time (CCT) is adopted as the measurable indicator to assess the interaction.


Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 226
Author(s):  
Milana Treshcheva ◽  
Irina Anikina ◽  
Vitaly Sergeev ◽  
Sergey Skulkin ◽  
Dmitry Treshchev

The percentage of heat pumps used in thermal power plants (TPPs) in the fuel and energy balance is extremely low in in most countries. One of the reasons for this is the lack of a systematic approach to selecting and justifying the circuit solutions and equipment capacity. This article aims to develop a new method of calculating the maximum capacity of heat pumps. The method proposed in the article has elements of marginal analysis. It takes into account the limitation of heat pump capacity by break-even operation at electric power market (compensation of fuel expenses, connected with electric power production). In this case, the heat pump’s maximum allowable capacity depends on the electric capacity of TPP, electricity consumption for own needs, specific consumption of conditional fuel for electricity production, a ratio of prices for energy resources, and a conversion factor of heat pump. For TPP based on combined cycle gas turbine (CCGT) CCGT-450 with prices at the Russian energy resources markets at the level of 2019, when operating with the maximum heat load, the allowable heat pump capacity will be about 50 MW, and when operating with the minimum heat load—about 200 MW.


2006 ◽  
Vol 129 (3) ◽  
pp. 254-265 ◽  
Author(s):  
Na Zhang ◽  
Noam Lior

Cogeneration can improve energy utilization efficiency significantly. In this paper, a new ammonia-water system is proposed for the cogeneration of refrigeration and power. The plant operates in a parallel combined cycle mode with an ammonia-water Rankine cycle and an ammonia refrigeration cycle, interconnected by absorption, separation, and heat transfer processes. The performance was evaluated by both energy and exergy efficiencies, with the latter providing good guidance for system improvement. The influences of the key parameters, which include the basic working solution concentration, the cooling water temperature, and the Rankine cycle turbine inlet parameters on the cycle performance, have been investigated. It is found that the cycle has a good thermal performance, with energy and exergy efficiencies of 27.7% and 55.7%, respectively, for the base-case studied (having a maximum cycle temperature of 450°C). Comparison with the conventional separate generation of power and refrigeration having the same outputs shows that the energy consumption of the cogeneration cycle is markedly lower. A brief review of desirable properties of fluid pairs for such cogeneration cycles was made, and detailed studies for finding new fluid pairs and the impact of their properties on cogeneration system performance are absent and are very recommended.


2014 ◽  
Vol 953-954 ◽  
pp. 890-895
Author(s):  
Hui Min Li ◽  
Cun Bin Li ◽  
Zhan Xin Ma

In recent years, with the rapid economic growth, the demand on the amount of energy in China is increasing. So the problem of how to improve the energy utilization efficiency and save energy consumption has to be tackled. The traditional CCR model and BCC model used in the study of provincial energy efficiency do not take the impact of technological progress into consideration. Therefore, the paper uses the generalized DEA method to research the energy utilization efficiency of China’s 29 provinces, that is, to evaluate and analyze the energy utilization efficiency by selecting the capital stock, employment and total energy consumption of China’s provinces as input factors and GDP, per capital GDP as output factors, and then draw tables showing each province’s change of average annual overall efficiency and the pure technology changes, and finally analyze the regularities underlying these changes.


2018 ◽  
Vol 276 ◽  
pp. 110-115
Author(s):  
Martin Ťažký ◽  
Martin Labaj ◽  
Rudolf Hela

The by-products of energy industry are nowadays often affected by new limits governing the production of harmful gases discharged into the air. These stricter and stricter criteria are often met by electricity producers by changing the combustion process in thermal power plants itself. Nowadays, the SNCR (selective non-catalytic reduction) application is quite common in the combustion process in order to help reduce the nitrogen oxide emission. This article deals with the primary measures of thermal power plants, which in particular consist of a modified treatment of raw materials (coal) entering the combustion process. These primary measures then often cause the formation of fly ash with unsuitable fineness for the use in concrete according to EN 450. The paper presents the comparison of the physico-mechanical parameters of several fly ashes with a different fineness values. The primary task is to assess the impact of non-suitable granulometry in terms of EN 450 on the other physico-mechanical parameters of fly ashes sampled within the same thermal power plant. Several fly ashes produced in the Czech Republic and surrounding countries were evaluated in this way.


Author(s):  
Hans Mu¨ller-Steinhagen

On October 30th 2009, a major industrial consortium initiated the so-called DESERTEC project which aims at providing by 2050 15% of the European electricity from renewable energy sources in North Africa, while at the same time securing energy, water, income and employment for this region. In the heart of this concept are solar thermal power plants which can provide affordable, reliable and dispatchable electricity. While this technology has been known for about 100 years, new developments and market introduction programs have recently triggered world-wide activities leading to the present project pipeline of 8.5 GW and 42 billion Euro. To become competitive with mid-load electricity from conventional power plants within the next 10–15 years, mass production of components, increased plant size and planning/operating experience will be accompanied by technological innovations which are presently in the development or even demonstration stage. The scale of construction, the high temperatures and the naturally transient operation provide formidable challenges for academic and industrial R&D. Experimental and theoretical research involving all mechanisms of heat transfer and fluid flow is required together with large-scale demonstration to resolve the combined challenges of performance and cost.


2014 ◽  
Vol 521 ◽  
pp. 530-535
Author(s):  
Meng Wang ◽  
Jian Ding ◽  
Tian Tang ◽  
Zhang Sui Lin ◽  
Zhen Da Hu ◽  
...  

The current situation of nuclear power plants at home and abroad is described, and the impact of large-scale nuclear power accessing to the grid is analyzed, specifically in the aspects of nuclear power modeling, simulation, load following, reliability, fault diagnosis, etc. Nuclear power accessing to the grid will bring a series of problems, the causes of each problem, the main solutions and future development directions are summarized.


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