Research On The Method For The Measurement Of The Bed Temperature Of The Circulating Fluidized Bed Boiler

The coal is the main primary energy in our country, the coal electricity seizies gross generation over 70%, and the situation that coal electricity is the dominant pattern in our power energy structure will not change in a long time. But coal as fuel exits the problems that pollution seriously and not efficient. Through the long-term practice, we found that the Circulating Fluidized Bed(CFB) boiler which is developed in these years has many advantages such as extensive adaption of fuels, low emission of SO2 and NOx, goog perfoumance of load adjustment, simple fuel treatment system and so on. That is popularized in our country and statistics indicated that there are more than thousand Circulating Fluidized Bed(CFB) boiler put to usr in our country. As a popular technique, the main characteristics are that the material (fuel and desulfurizer) is in flowing state during circulating buring..The bed temperature is one of the most important parameter for the safety and economical operation of the CFB boiler, the significant basis for monitoring the buring and fluidifying situation in the dense zone and preventing furnace coking, the important temperature spot of controlling the combustion situation, one of the most important step to ensure the Master Fuel Trip(MFT), and also affects the environment effect of boiler operation. From the practical operating situation, high bed temperature not only goes down the desulfuration efficiency, but also leads to coking and materials can't buring in fluidized state; low bed temperature goes down the combustion efficiency, meanwhile it makes the boiler combustion instability and the material can not burn. In order to ensure the safety and economical operation of the CFB boiler, we must real-time control the temperature. The accurate measuring of bed temperature is the premise of assuring the bed temperature can control stably and operate reliably, this paper research the measuring technology of bed temperature.Bed temperature signal is tested by bed temperature measuring sensor which is arranged in furnace, based on the existing problems of normal bed temperature measuring sensor during actual operation such as bad resistance to high temperature shock, bed performance in corrosion-resisting. This resulting the problems such as the decline of the measurable precision, short of service life, poor economic benefits. This paper analyzes the basic theory of bed temperature measuring sensor and researches the operational environment in boiler bed, then defines the main performance of bed temperature measuring instrument and provides corresponding improved measures. It research and produce the bed temperature instrument which has advantages such as high stability and reliability, good economic and long service life from the design of bed temperature instrument structure, the selection of measuring element, application of new material of wear-resistant cannula and the light-sound sensitive alarm of the wear of thermocouple cannula.