Study On Pretreatment Of Crop Straw Densified Biofuel

With Straw Densified biofuel technology promotion and application in our country, more abandoned crop stalks to get better energy utilization. But the source of widespread crop straw materials, sources of dispersion, resulting in high levels of impurities in the material, and a variety of mixed materials, other crops often use of plastic film mulching technology, resulting in more crop residue mixed with straw mulch. These factors affect the stability of Densified biofuel process, affecting the life of molding equipment, but also affect the physical and chemical properties and combustion characteristics of briquette. In this study, the research Straw Densified biofuel pretreatment stage densifying process, the source of the classification study of impurities, impurity removal mechanisms and equipment, research materials mixed mechanism, mixed programs, research mulch of straw combustion residues mixed with the gas emission characteristics. The results obtained the following conclusions:1) The crop stalks Densified biofuel material impurities and impurity modes are studied. Straw material impurities into metal, plastic fabrics,>5mm gravel and<5mmof the dust. The main source of impurities harvest, transport and other sectors of impurities, the total content of about0.3%, due to site clearance and other management issues brought impurities trials impurity content up to3%. Straw impurities in the material, magnetic metal impurities can be removed by a magnet to remove the plastic auger and other soft fabric impurities,>5mm gravel sorter available gas impurities removed<5mm available drum screening dust removal.2) The problem of crop straw drum screening material dust impurities are studied to determine screening parameters. Straw materials screening, the drum sieve speed range20-32r/min, tilt range is3～9°optimum aspect ratio can be selected according to the text obtained in accordance with the screening rate curve fitting requirements.3) Mixed crop straw combustion characteristics and kinetic analysis were studied. Add peanut shells mixed materials, volatile phases in the activation energy decreased, reducing the intensity of combustion, combustion characteristics and kinetic parameters greatly influenced by peanut shells; adding a small straw combustion stability of mixed materials characteristics tend to have deteriorated, their combustion characteristics and kinetic parameters of wheat straw less affected4)Densified biofuel characteristics of mixed straw are studied. Add peanut shells improvement of the main raw material of corn stalks forming characteristics, wheat straw added to improve the main raw material of corn stalks forming characteristics ineffective. Add peanut shell materials orthogonal experiments showed that the percentage proportion of peanut shell materials selection to add preferred range is10%to20%, the percentage of moisture content of the material selection is preferably mixed in the range of21%to24%.5) Analysis of emissions and residues mixed with straw mulch burning. Mixed materials due to residual film integrated combustion characteristics are improved, and the other mixed materials and combustion residue mulch compared to lower the ignition point of combustion, combustion time becomes longer, so easy to control combustion, combustion, can reduce the amount of fat smoke; mix of solid material in the molding after forming particles in the normal combustion of fuel, CO, SO2, NOx emissions of the three gases of combustion greatly reduced, improving the combustion of materials of environmental contamination.