Study On Characteristics Of Straw Burning And The Design Of Dust Removal System

As the shortage of fossil energy is becoming increasingly serious,the burning and utilization of biomass straw has begun to receive widespread attention.Biomass energy is the only renewable clean energy source on the earth.Because it has the characteristics of large volatile matter ratio,strong char activity,and small environmental damage after combustion,it is very suitable for a large number of development and transformation and utilization.Environmentally friendly fuels.However,with the development of China's national economy,the energy structure of vast rural areas in China has also undergone tremendous changes.A large number of straws have been abandoned or burned in the fields,causing serious waste of resources and environmental pollution.At present,the utilization of straw in China mainly includes direct combustion,pyrolysis,and fermentation.There are four combustion methods for straw combustion,namely,suspension combustion,traditional dispersion combustion,bale combustion,and compact combustion.However,in these four combustion methods,the traditional bulk burning combustion efficiency is low,fly-ash combustion is suspended seriously,straw is not easy to transport and storage,high energy consumption for molding combustion,and straw baling combustion method combines the advantages of the above three combustion methods.Bundles of fuel increase the density of straw-like biomass,which is convenient for transportation and storage.At the same time,the method of bundling is less energy-consuming than compression molding.Therefore,bundling and burning is the most promising combustion method in the future.This paper mainly carried out research work from the following three aspects:(1)Bundle burning characteristic experiment and ash characteristic test: This paper adopts the TG-DTG combination technique to carry out thermogravimetric analysis of three kinds of common combustion methods of burning,bundling and forming of corn stover,and calculates the experimental data.With the drawing,the combustion characteristics of the three combustion modes were obtained,and a comparison was made to find out the differences between the two types of combustion methods.The test results show that the bundle burning,like burning and burning,must undergo three stages: moisture evaporation,precipitation of volatiles,and combustion and burn-out of fixed carbon.Because the bundled fuel has a unique size structure,it is not conducive to fuel internals.After heat and mass transfer,the peak value of the volatile matter precipitation time is later than that of other combustion methods,and the characteristic Rv of the volatilization analysis after the bundle burning is 0.3250×10-3·K-2·min-1,which is far lower than that of the dispersion combustion and the molding combustion method.The volatile matter inside the bundled fuel is not easy to precipitate,the precipitation process is relatively stable,and maintains a long time;in the combustion stage of fixed carbon,there is a more prominent peak value of the weight loss of the bundled fuel;the paper has independently designed the bundle burning experimental platform.The actual combustion process of the bundled fuel was simulated by a bundling test bench,and the results of the thermogravimetric test were verified by experiments.The experimental results show that the two are similar.The paper also carried out a series of ash characteristics experiments on the ash of straw bundled fuel,and obtained the ash characteristics parameters of the bundled ash: the average value of the infiltration of the bundle burned ash is 10.21mm/min,>8.0,with good infiltration Sex is a hydrophilic substance;the experimental average of hygroscopicity for bundled ash for 24 hours is 6.315%,the average value for 48 hours is 7.147%,and bundled ash is divided into highly hygroscopic dust particles;the specific resistance of bundled ash The average value is 1.953×10 6 ?.cm,which is close to the low specific resistance range.The ash characteristics test confirms the physical and chemical characteristics of the bundled ash,which has a certain guiding significance for the future design of dust removal equipment.(2)Dust-removing design of baling equipment: The paper combines the combustion characteristics of baled fuel with the design of the air supply system for the bundling boiler,adopts segmented air supply,and proposes a design idea for a new type of boiler air supply system.At the same time,according to the size and structure characteristics of straw-bundled fuel,the structure of the boiler is selected,and the boiler is designed and calculated as a whole.According to the ash characteristic index of bundle ash,the most suitable dust collectors—water film dust collectors and electrostatic precipitators,two-stage dust removal methods are also selected.Boiler boilers can meet the national emission standards while being clean and highly efficient.(3)Experimental verification of the bundling equipment: The paper finally carried out the experimental verification of the bundling boiler designed by the research group.The experimental results show that the smoke content of the flue gas emitted from the bundling boiler is about 27 mg·m-3,which is lower than the national average.The discharge standard is 50mg·m-3.