Combustion Experiment And Application Study Blending With Semi-coal In Power Station Boiler Of 135MW

Semi-coal,the good quality Jurassic coal which is rich in NW China,is green fuel formed of pyrolysis by dry distillation under middle low temperature.It is translated into Chinese called “blue coal”,because of its blue flame when it burns.Semi-coal has various benefits,especially having high calorific value and good environmental performance.The problem of environmental pollution caused by coal burning is getting worse in recent years.Semi-coal as a new clean energy has great environmental advantages,but many questions remain,which lead to overcapacity,downstream market contraction and so on.This paper researches semi-coal’s characteristic analysis comparing the common coal come from YuLin district,and the experimental study of the burning process mixing semi-coal with raw material in a power station boiler of 135 MW,so as to make semi-coal to be generalized across the power plant boiler and broaden applications for picking up excess capacity.The experiment results show that,comparing common coal,semi-coal has characteristics like a little high Mt/Mad & Ad,low Vad/Vdaf,a little low calorific value,high fly ash resistivity and high mechanical wear.With medium speed mill direct-firing pulverizing system,the coal-fired power plant well suit for blending combustion previously mixed semi-coal of which the maximum limit is 33%.Under the operation of blending combustion with semi-coal in bituminous coal fired boiler of 135 MW,the water-steam system parameter runs normal,the slagging on burner nozzle and boiler water wall is reduced,the desulfurization costs down,dust density is decreased,but the consumption of centrifugal fan at a time and coal consumption of power supply rise slightly,coal mill’s capacity decline and components wear out more quickly.The wear of mill coal is the main factor that constrains boiler using semi-coal from a technical point of view.The power station should,at first,make mill parts and separator blade with professional wear-proof handling,to guarantee the operation of pulverizing system stably.Economically,the cost per unit power generation is main due to fuel material price,despite using semi-coal has some situations caused by more coal consumption,increasing operation and maintenance cost,but power station’s composite cost will reduce if blending combustion with semi-coal which has low relative price.