Research On Straw Block Heating Equipment For Household Use

Based on the increasing depletion of conventional energy reserves in China,the severe weather such as haze caused by fossil energy combustion and the extensive heating mode in northern rural areas in winter,the subject is born.This paper mainly focuses on the research of straw block household heating equipment for heating in northern rural areas in winter.In recent years,our group has designed a straw block heating equipment with the function of automatic feeding.Based on the preliminary work,this project optimizes the combustion equipment to realize the efficient and clean heating in the northern rural areas in winter.First of all,this paper analyzes the elements and industry of straw briquette fuel,coal and other fossil fuels.The results show that the fixed carbon content of straw block fuel is low,the volatile content is high,and the S content is far lower than that of coal.Then,the thermogravimetric analysis of peanut shell block fuel was carried out.The thermogravimetric curve（TG）,derivative thermogravimetric curve（DTG）,differential thermal analysis（DTA）and differential scanning calorimetry（DSC）were measured under the experimental conditions of heating rate of 20℃2 min,air volume of 100ml 2 min and heating to 1000℃.Furthermore,the combustion calculation of straw block fuel is carried out to obtain the data of combustion process,including:fuel quantity required for fuel combustion,air quantity,flue gas quantity and flue gas enthalpy.In addition,the theoretical formula for the calculation of the combustion thermal efficiency of the combustion equipment is given.The combustion thermal efficiency of the straw block household heating equipment is calculated by the positive balance method and the reverse balance method.Then,based on the three problems of straw block combustion equipment designed in the previous work,the combustion equipment is optimized,which are the poor adaptability of the automatic feeding device to the fuel and the phenomenon of material stucks in the actual combustion process;exhaust gas has high temperature which results the serious heat loss;and the high emission of pollutants.（1）the drag plate is designed as a double layer,and the middle part is connected with a hard spring to increase the elastic displacement in the process of fuel rising.（2）a heat exchange water tank is arranged in the tail flue,which is separated from the boiler water jacket.The cold water can be used as domestic hot water after being heated.（3）a 100 mesh filter screen is arranged at the outlet of the flue to reduce the smoke content.The feed stability,thermal efficiency and pollutant emission of the optimized straw block combustion equipment were tested.Finally,the combustion equipment can transport2.5-3.5kg2h block fuel continuously and stably;the thermal efficiency is as high as80%;the content of CO,CO_2,NO_Xand dust is far lower than the national emission standard.Finally,in order to explore whether the heating equipment has good adaptability to other block fuels,this paper carried out the fuel adaptability research of straw block household heating equipment.The applicability of the heating equipment was studied with sawdust and peanut shell,willow branch and pear branch.A series of experiments show that the heating equipment has good adaptability to other block fuels.