機(jī)械與能源動(dòng)力畢業(yè)設(shè)計(jì)外文翻譯--熱力發(fā)電廠發(fā)展的替代趨勢(shì)（英文）

1、Alternative trends in development of thermal power plantsVitaly A. Prisyazhniuk *,1Doctor of Physical Chemistry, Har Hatzofim Street 13/11, Holon 58493, IsraelReceived 1 December 2006; accepted 19 March 2007 Available on

2、line 4 April 2007AbstractThermal (or fossil fuel) power plants (TPP) are the major polluters of man’s environment, discharging into the atmosphere the basic product of carbon fuel combustion, CO2. It is this very gas tha

3、t accounts for the greenhouse effect causing the global climate warm-up on our planet. A natural solution of the problem of reducing carbon dioxide discharge into the atmosphere lies in power saving, thus reduc- ing the

4、amount of the fuel burnt. This approach can be justified from any standpoint, both economically and ecologically. The ideal way of solving the problem would be to completely give up burning carbon-containing fuel, such a

5、s coal, petroleum products, and other power resources of organic nature. This work is intended to outline the ways of reducing consumption of fuel by TPP and, consequently, of reducing their discharging into the atmosphe

6、re the gases producing the greenhouse effect. One of the ways lies in changing the thermophysical characteristics of the working medium, which becomes possible if we can modify the conventional working medium, that is wa

7、ter, or can use some working medium with quite different thermophysical properties. The article dwells on various technological ways providing for a practical solu- tion of the problem, such as the Kalina cycle; modifica

8、tion of water properties by way of magneto-hydrodynamic resonance (MHD res- onance); and employing, in the thermodynamic cycle of Thermal Power Plants, liquids boiling at temperatures which are lower than that of the env

9、ironment. ? 2007 Elsevier Ltd. All rights reserved.Keywords: Saving power; Efficiency; Reducing discharges into the environment; Thermal power plant1. IntroductionHistory of civilization and the progress in science and t

10、echnology are closely associated with the growth of power consumption. A direct consequence of the developing heat power engineering based on combustion of carbon-con- taining fuel and of the growing amount of electric p

11、ower produced is the increasing consumption of fuel-energy resources. Consuming coal, oil and gas to produce electric power, and consuming over 1% of the atmospheric oxygen,heat power engineering replaces it by SO2, NOx,

12、 and CO2, which aggravates the greenhouse effect. Let us now turn to the data published by the GAO (General Accounting Office, USA) on June 20, 2002 [1]. Electric power stations of the USA that began operating before 197

13、2 discharged, in 2000, 59% of the sulfur dioxide, 47% of the nitrogen oxides, and 42% of the carbon dioxide of the total discharge by the fuel-fired plants, while having produced only 42% of the total electric power. Let

14、 us resort to simple calculations to show the correla- tion between gaseous discharge from the newer and the old power stations in reference to the unit of their actual capac- ity. To do so we shall use a simple logic: i

15、f the older power stations produced 42% of the electric power obtained, the newer ones produced (100 ? 42)% = 58%; if the older sta- tion discharged into the atmosphere 59% of the SO2, the newer ones discharged (100 ? 59

16、)% = 41%, and so on for1359-4311/$ - see front matter ? 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.applthermaleng.2007.03.025* Tel.: +972 3 558 9873. E-mail address: vitalpris@yahoo.com1 Since 2002 is retired.

17、 The last place of work: Institute of Problems in Mechanical Engineering of the Ukrainian National Academy of Sciences, Kharkov, Ukraine.www.elsevier.com/locate/apthermengAvailable online at www.sciencedirect.comApplied

18、Thermal Engineering 28 (2008) 190–194resonant frequencies thus causing a drop in the heat of vaporization or in the heat capacity. Unfortunately, the properties of water are such that a decrease in heat capacity results

19、in an increase in the heat of vaporization and vice versa. Calculations show [4] that through using MHD resona- tors, it is quite possible to raise the efficiency of the TPP by 10%. That will result in reducing fuel cons

20、umption by 29% (at the unchanged installed capacity of the TPP), reducing solid and gaseous discharge by 29%, and reducing dis- charge of heat by 52%.2.2. Employment of a composite working mediumAt the beginning of the 9

21、0s in the USA at a 1 MW pilot plant, there was implemented the well-known A. Kalina cycle in which an increase in efficiency of the thermal power station is achieved by using, as a working medium, a water solution of che

22、micals, such as, for instance, ammonia, monoethylamine, diethylamine, and the like. For example, when ammonia is dissolved in water the heat capacity of the solution formed is lower than that of water. Besides, when diss

23、olving one gram-molecule of ammonia in a litre of water 8.28 kcal of heat is released, which is just enough to heat up a kilogram of 14% ammonia solution formed almost to 100 ?C. Thus, the heat released on dissolving can

24、 save, when heating a litre of water from 30 ?C to 100 ?C, about 70 kcal of heat or 0.01 kg of equivalent fuel. The Kalina cycle is realized as follows: some ammonia is added to feedwater before it enters the steam gener

25、ator. Owing to the heat released on dissolution of ammonia and lowered heat capacity of the resulting solution, its heating to the boiling temperature requires less fuel. Then the steam and gaseous ammonia are separated,

26、 condensed separately, and then the water and ammonia are mixed again before being fed to the steam generator [5]. In the chemical industry the process of separating water and ammonia is extensively used at the stage of

27、distilling filter liquid in producing soda ash by the Solve method. The pilot heat power plant operating by the Kalina cycle has practically proved that raising the efficiency of a TPP by 10% and reducing thus the fuel r

28、ate by 20% is quite achievable. Since the character of the fuel used does not play a principal role, the Kalina cycle results in reducing the discharge of dust, CO2 and SO2 in proportion to saving fuel, which is by 20%.

29、A drawback of the Kalina cycle, as compared with the method of MHD resonance mentioned in Section 2.1, is the impossibility of employing it at an operating TPP using the Rankin cycle.2.3. Replacing the conventional worki

30、ng mediumLet us dwell more closely on the technology of produc- ing electric power by way of using the heat of the environ- ment which we consider to be the most promising from the point of view of reducing fuel consumpt

31、ion. To begin with,let us review the basic principles of physics and physical chemistry that make the foundations of said technology and have become axiomatic today.Axiom 1. It has been established [6] that one kmol of a

32、ny gas occupies, at normal conditions (Pn = 101.325 kPa; Tn = 288.15 ?K), the volume of Vmn = 22.414 m3/kmol.Axiom 2. Vaporization and condensation are all examples of the first-order phase transition.The first-order pha

33、se transition (PT1) is characterized by changing the aggregative state of substance at the point of transition. In transition from condensed to gaseous state or vice versa, there takes place an abrupt change in the vol-

34、ume of the kmol of the substance, which is a regular trend with all substances. The volume of one kmol of any substance in liquid state at the boiling temperature and normal pressure isV lqboil ¼ kM=qlqboil; ð2

35、Þwhere kM is the weight of kmol, and qlqboil is the density of substance in liquid state at the boiling temperature. The volume of one kmol of any substance in gaseous state at normal conditions isV ng ¼ kM=qng

36、 ¼ 22:141; ð3Þwhere qng is the density of the substance in gaseous state at normal conditions. As the weight of kmol is permanent with changing of the aggregate state of substanceV lqboil ? qlqboil ¼

37、V ng ? qng; ð4ÞV ng ¼ V lqboil ? qlqboil qng ¼ 22:141: ð5ÞLet us consider some numerical examples borrowed from reference sources. While in the liquid state a kmol of water has a volume of 0

38、.018 m3, in the gaseous state, under normal conditions, it has a volume of 22.414 m3 (see Axiom 1 above), that is 1245 times greater. While in the liquid state a kmol of nitrogen has a volume of 0.035 m3, in the gaseous

39、state, under normal conditions, it has a volume of 22.414 m3 (see Axiom 1 above), that is 640 times greater. While in the liquid state a kmol of carbonic dioxide has a volume of 0.040 m3, in the gaseous state, under norm

40、al conditions, it has a volume of 22.414 m3 (see Axiom 1 above), that is 561 times greater. While in the liquid state a kmol of propane has a volume of 0.076 m3, in the gaseous state, under normal conditions, it has a vo

41、lume of 22.414 m3 (see Axiom 1 above), that is 294 times greater.Axiom 3. From the equation of state for the ideal gas [6], it follows:P nV n T n ¼ P tV t T t ; ð6Þ192 V.A. Prisyazhniuk / Applied Thermal E