焦煤炉中英文对照外文翻译文献.docx

1、焦煤炉中英文对照外文翻译文献中英文对照外文翻译文献(文档含英文原文和中文翻译) 原文： Energy saving and some environment improvements in coke-oven plantsAbstractThe enthalpy of inlet coal and fuel gas is discharged from a coke-oven plant in the following forms: chemical and thermal enthalpy of incandescent coke, chemical and thermal enthalp

2、y of coke-oven gas, thermal enthalpy of combustion exhaust gas, and waste heat from the body of the coke oven. In recent years the recovery of several kinds of waste energy from coke ovens has been promoted mainly for energy saving purposes, but also for the improvement of environmental conditions.

3、Among the various devices yet realized, the substitution of the conventional wet quenching method with a coke dry cooling is the most technically and economically convenient. The aim of this paper is mainly a review of the main types of coke dry cooling plants and a detailed examination of the infiu

4、ence of some parameters, particularly of temperature and pressure of the produced steam, and on the energy efficiency of these plants. 1. Introduction1.1. Usable energy The energy of a system-environment combination is usually defined as the amount of work attainable when the system is brought to a

5、state of unrestricted equilibrium (thermal, mechanical and chemical) by means of reversible processes, involving only the environment at a uniformly constant temperature and pressure and comprising substances that are in thermodynamic equilibrium. Notwithstanding the quite different meaning, chemica

6、l energies differ from lower heating values slightly, as is discussed in 1,2. The chemical energy generally falls between the higher and lower heating values but is closer to the higher.Nomenclaturecpconstant pressure heat capacity kJ/(kg K)Exenergy kJExuusable energykJexspecific energykJ/kgGvvolume

7、 flow rate m3(nTp)/hGv*specific volume flow rate m3(nTp)/tdry cokeispecific enthalpy kJ/kgppressure barsspecific entropy kJ/(kg KTtemperature C, KToenvironment temperature C, Kvspecific volume m3/kgenergy effciency dimensionless Nonetheless, the chemical energy is not suitable for quantifying the te

8、chnical value of a fuel for two reasons: (i) Prior to considering heat transfer, it is necessary to account for the essentially irreversible combustion process, which decreases the exergies of various fuels greatly in different ways. (ii) The work corresponding to reversible expansion of several com

9、ponents (in particular CO2) down to their atmospheric partial pressures cannot be obtained from the combustion gas, as is implicit in the energydenition. In addition, this work differs with fuel type. Consequently, Bisio 3 defined usable energyas the exergetic value following an adiabatic combustion

10、 with a given excess air ratio (e.g., 1.1) minus the energyloss resulting from irreversible mixing of com-bustion gas with the atmosphere after having reached atmospheric pressure and temperature.The ratio of usable energyto lower heating value of a given fuel is termed the merit factor. This factor

11、 is always less than one and increases as the technical and economic values of a fuel rise. The parameter “usable exergy”, as has been dened and applied in 3, is suitable in the examin-ation of plants, that utilize fuel mixing, when the aim is to reduce both the total fuel consumption and, chiefly,

12、the more valuable component one.1.2. Coke-oven energy recoveries The chemical energy of a fuel gas, which is used for a coke oven, amounts to 2500-3200 MJ/tdry coal. This energy, degraded to thermal energy of various operative values, is discharged from the plant in such forms:1. Thermal energy of i

13、ncandescent coke (43-48%)2. Thermal enthalpy of coke-oven gas (24-30%)3. Thermal energy of waste gas (10-18%)4. Permeability, convection and radiation heat from the external surface of coke oven, and various losses (10-17%) The oil crisis of 1973 created a strong impulse towards a new thinking on th

14、e consumption and rational utilization of energy, particularly in the highly industrialized countries with limited indigenous energy resources. At the same time, attention throughout the world was also increas-ingly focused on environment problems.The possible utilization of the thermal energy of in

15、candescent coke is dealt with in many papers . Usually, in coking technology the coke is cooled by being sprayed with water under special quenching towers. In recent years, the various types of dry cooling plants allow the recov-ery of nearly 80% of the thermal energy of incandescent coke. The possi

16、bilities of utilizing reco-vered energy are as follows:1. Production of steam and electricity.2. Preheating of coking coal.3. Room heating. The thermal energy of coke-oven gas, which is the second largest in the above listing, has so far been rarely utilized. Various studies, however, have been carr

17、ied out for the possible utilization of this waste energy and a technique has recently been commercialized in Japan.The thermal energy of combustion exhaust gas is utilized to preheat both the combustion air and fuel gas mixture through a large-capacity regenerator. Consequently the waste gas temper

18、ature is reduced to approximately 200C. Lately, the further recovery of heat from waste gas has been reported in a few cases using a heat pipe installed in the ue.The various kinds of heat wasted from the coke-oven external surface have been decreased by the reinforced sealing and better thermal ins

19、ulation of coke ovens.In the following sections, the main types of coke-oven energy recoveries will be considered for a comparison.1.3. Protection of the environment As with the problem of energy saving and recovery, the last years have been characterized by increased prevention of atmospheric and w

20、ater pollution by industrial emissions and domestic wastes. Work to control atmospheric pollution has been carried out in all developed countries. According to Zaichenko et al. , as a result of including measures for environmental protection, the investment and the coking costs are increased by 15%.

21、 However, if the calculations included allowance for losses caused by adverse effects of atmospheric pollution on workers health, instal-lation of engineering facilities for maintaining clean air can be cost-effective. In any case, it is obvious that an environmental facility is particularly temptin

22、g when, as with coke dry cooling plants, in addition to environment advantages, an energy recovery can be associated, even if the investment costs are higher and not justied only by energy saving.2. Coke dry quenching2.1. Methods for energy recovery and saving from coke at the coke-oven outlet The i

23、dea of recovering thermal energy from incandescent coke by means of an inert gas dates back to the early 1900s. The rst industrial plants, designed particularly by the Sulzer Brothers (Winterthur, Switzerland) were carried out in the 20s and 30s both in the USA and in Europe (Germany, France, UK, Sw

24、itzerland) 4,18. However, the greater investment costs of dry quench-ing plants, in comparison with those of the wet quenching ones, were amortized with difculty in a period in which energy was very cheap. Consequently, dry quenching plants were given up.In the early 1960s, a new interest arose: in

25、the USSR, dry cooling plants, which basically followed the Sulzer design, were built with the primary aim of preventing the coke from freezing in winter, as happens with wet quenched coke. The plant, constructed in various countries accord-ing to the Soviet Giprokoks process 6, is schematically show

26、n in Fig. 1. The red-hot coke, at a temperature of about 1100C, is pushed from ovens, A, into containers placed on cars. Loaded cars are moved to the dry cooling plant, where containers, B, are lifted by bridgecrane, C, and unloaded through the charging system, D, into pre-chamber, E. Then, hot coke

27、 is transferred into the cooling chamber, F, in small batches. After leaving the cooling chamber through the discharg-ing system, G, coke runs, at a temperature of about 200C, onto conveyor belt, H. Coke is refriger-ated by a circulating gas, composed mainly by nitrogen and moved by the main blower,

28、 I. This gas transfers thermal energy in boiler, N, which produces superheated steam, O, at a pressure up to 100 bar. Before entering the boiler, the gas is scrubbed in the coarse de-duster, J, removing coarse particles of coke dust to protect the boiler surface from erosion. After leaving the boile

29、r, the gas streams through the ne deduster, K, where ne dust is scrubbed out.In 1983 a dry cooling plant, schematically shown in Fig. 2, began operation in Germany. Its main characteristic is that 1/3 of the thermal energy is transferred directly from the coke to the vaporizing water and the remaini

30、ng 2/3 through the inert gas. The advantages are a lower quantity of circulating gas with a correspondingly lower consumption of electrical energy by the blower and a greater energy recovery. Refrigerating walls in the cooling chamber represent the critical point of the plant i.In Germany, a combina

31、tion of the coke dry cooling and coal preheating plant has been developed 5,9,1416. This system realizes primary energy saving (e.g. gas) instead of energy recovery of lower energyvalue (steam) and thus it is thermodynamically preferred (see, e.g., 29). In addition, the well-known advantages of the

32、single processes with respect to coke quality and increased output have been conrmed. The completely closed system permits significant environmental improvements in the coking plant sector, avoiding the immissions of dust into the atmosphere in a practically complete way. Jung 13 considered the convenience of using water gas (H 2 +CO) as the heat transfer fluid.Indeed, water gas has a thermal diffusivity three times that of nitrogen, and thus it allows us to reduce