毕业设计-外文翻译-燃煤锅炉.doc

Controlling the Furnace Process in Coal-Fired Boilers The unstable trends that exist in the market of fuel supplied to thermal power plants and the situations in which the parameters of their operation need to be changed (or preserved), as well as the tendency toward the economical and environmental requirements placed on them becoming more stringent, are factors that make the problem of controlling the combustion and heat transfer processes in furnace devices very urgent. The solution to this problem has two aspects. The first involves development of a combustion technology and accordingly, the design of a furnace device when new installations are designed. The second involves modernization of already existing equipment. In both cases, the technical solutions being adopted must be properly substantiated with the use of both experimental and calculation studies. The experience Central Boiler-Turbine Institute Research and Production Association (TsKTI) and specialists gained from operation of boilers and experimental investigations they carried out on models allowed them to propose several new designs of multi fuel and maneuverable—in other words, controllable—furnace devices that had been put in operation at power stations for several years. Along with this, an approximate zero-one-dimensional, zone wise calculation model of the furnace process in boilers had been developed at the TsKTI, which allowed TsKTI specialists to carry out engineering calculations of the main parameters of this process and calculate studies of furnaces employing different technologies of firing and combustion modes . Naturally, furnace process adjustment methods like changing the air excess factor, stack gas recirculation fraction, and distribution of fuel and air among the tiers of burners, as well as other operations written in the boiler operational chart, are used during boiler operation. However, the effect they have on the process is limited in nature. On the other hand, control of t