Study On The Emission Characteristics Of Particulate Matter Based On The Biomass Three-component Combustion

The development of biomass energy is an important countermeasure to cope with the energy crisis and environmental pollution.Biomass energy can not only quickly dispose agricultural and forestry wastes in cogeneration,but also has high economic efficiency,sufficient resources,recyclable utilization,energy saving and environmental protection.When used for heating,it is in line with the National 14th Five-Year Plan for renewable energy.High attention is paid to non-electric utilization methods such as heating.However,in recent years,it has been discovered that biomass emits a large amount of particulate matter during the combustion process,resulting in aggravated haze weather and endangering human health,which greatly limits the large-scale application.At present,many scholars have carried out various studies on the combustion particulate matter emissions of biomass,but most of them focus on a specific biomass,and there is a lack of more general research.Therefore,from the perspective of biomass components,this article explores the effects of biomass components,alkali metal existence forms and alkali metal content through the combustion and pollutant emission characteristics of the three components of cellulose,hemicellulose and lignin.The influence law of combustion particulate matter generation,and the influence of component interaction and alkali metal coupling on combustion particulate matter generation are explored.The specific content is as follows:Firstly,using thermogravimetric balance to study the combustion characteristics of the three components of biomass and corn stalks.The results show that there are obvious differences in the combustion thermogravimetric curve between the three components of biomass.When the heating rate is 10℃/min,the maximum weight loss peaks of cellulose,hemicellulose,lignin and corn stalk correspond to temperatures of 327℃respectively.,294℃,471℃,298℃,the peak values are 32.68%/min,8.16%/min,11.61%/min,6.4854%/min,respectively.The thermogravimetric curve of corn stalk is always between the thermogravimetric curves of the three components of biomass.As the heating rate increases,the peak temperature and peak value of the maximum weightlessness increase.From the comprehensive combustion index,the combustion performance of the four samples is:cellulose>lignin>cornstalk>hemicellulose.The four methods of FWO,KAS,Frienman and Starink are used to calculate the activation energy of cellulose,hemicellulose,lignin and corn stalk at different conversion rates.The FWO method has the highest average correlation coefficient,and the average activation energy obtained is 155.78.k J/mol,194.27 k J/mol,85.83 k J/mol and 169.53 k J/mol.Calculated by the master curve method,the cellulose is the random nucleation model A2,the hemicellulose and corn stalk are both the chemical reaction progression model F7,and the lignin is the diffusion mechanism model D2.Subsequently,a combustion experiment was carried out in a fixed bed reactor,combined with a low-pressure shock sampling device to collect particulate matter,and the three-component and different content and different forms of potassium salt（potassium chloride,potassium acetate,potassium sulfate）on combustion particulate emissions were studied.Impact.The results showed that there is a significant difference in the emission curves of combustion particulate matter between the three components and the cornstalk.The three components are distributed in a single mode,while the cornstalk is distributed in a bimodal distribution.The PM₁₀emissions of cellulose,hemicellulose,lignin and corn stover were 0.315,0.645,5.271,and 10.038 mg/g,respectively.The EDX results show that the main elements of the three-component combustion particulate matter are Na,K,S,and Si,while the corn stalk combustion particulate matter contains more Ca,Mg,Al,Cl,P in addition to the above elements.After adding 1%-3%of different forms of potassium salts,the PM₁₀content of cellulose,hemicellulose,and lignin increased to 9.856-27.722,7.352-43.056,10.240-29.998 mg/g,respectively.For cellulose and lignin,from the perspective of PM₁₀,the release effects of the three kinds of potassium salts on burning particulate matter are potassium acetate>potassium sulfate>potassium chloride,and for hemicellulose,potassium acetate>chlorination.Potassium>potassium sulfate.During multi-factor analysis,it was found that the addition of potassium salt had a more significant impact on particulate matter emissions than the composition of raw materials and the types of potassium salts.Within the scope of the experiment,with the increase of potassium salt addition,the emissions of three-component combustion particulate matter continued to rise.Finally,the three components were blended in proportions of 25%/75%,50%/50%,and 75%/25%,and then burned to study the effect of the interaction between the components on PM emissions.At the same time,on the basis of interaction,three different forms of potassium salts（potassium chloride,potassium acetate,potassium sulfate）were added to study the effect of interaction on the particulate matter emissions caused by potassium salts during the combustion process.The study found that the interaction of cellulose and hemicellulose has a slight increase in particulate matter emissions.When the blending ratio is 50%/50%,the emission of the main particulate matter PM_0.1is 0.383mg/g,which is higher than the theoretical value.4.93%.The interaction of cellulose and lignin has little effect on particulate matter emissions.The interaction of hemicellulose and lignin has a slight emission reduction effect on particulate matter emissions.When the blending ratio is 50%/50%,the emission of the main particulate matter PM₁is 2.463 mg/g,which is13.2%lower than the theoretical value.For the three interactive samples,adding the three forms of potassium salts used in the experiment,the combustion particulate emission curve is lower than the theoretical value,indicating that the interaction between the three components has a certain inhibitory effect on the release of potassium salts.The interaction of cellulose and hemicellulose is more conducive to suppressing the particulate matter caused by potassium sulfate,reducing 13.0%compared to the theoretical value;the interaction of cellulose and lignin is more conducive to inhibiting the particulate matter caused by potassium chloride,which is less than the theoretical value.10.0%;the interaction of hemicellulose and lignin is more conducive to suppressing the particulate matter caused by potassium acetate,reducing 9.4%compared with the theoretical value.