| Chinese medicine is the essence of Chinese history and culture,and the Chinese medicine industry occupies an important position in China’s pharmaceutical industry system.The vigorous development of the Chinese medicine industry will inevitably produce a large amount of waste Chinese medicine residue.If it is directly discharged into the environment,it will seriously pollute the water body and the surrounding environment.How to deal with the Chinese medicine residue becomes an urgent problem to be solved.The ginkgo biloba medicine residue produced in the extraction process of ginkgo ketone esters have a variety of biological toxicity,and the traditional Chinese medicine residue treatment modes have more or less certain safety risks.Ginkgo biloba medicine residue is a potential biomass resource.If it is processed into biomass pellet fuel,its toxicity can be effectively degraded through high-temperature combustion,so as to realize the resource utilization of ginkgo biloba medicine residue.Therefore,it is a safe and feasible way to process ginkgo biloba dregs into biomass pellet fuel.This paper studies the preparation process of ginkgo biloba medicine residue pellet fuel from the perspective of energy consumption and physical characteristics,in order to obtain pellet fuel with higher energy and better quality.The main research contents and conclusions are as follows:（1）The hot-air thin-layer drying test of ginkgo biloba medicine residue was carried out by hot-air drying method,and the effects of different drying temperatures on the drying characteristics and drying kinetics of ginkgo biloba medicine residue were studied.Use 9common mathematical models to curve-fit the data of the moisture ratio with the drying time,obtain the specific parameters of the model expression.Use the determination coefficient R2,the root mean square error eRMSEand the chi-square test value X2 as evaluation index to determine the best hot-air thin-layer drying model of ginkgo biloba medicine residue.The test results show that the higher the drying temperature,the faster the moisture ratio of ginkgo biloba medicine residue per unit time decreases,the greater the maximum drying rate,the greater the effective moisture diffusion coefficient,and the shorter the drying time.According to Fick’s law,it can be calculated that the drying temperature is in the range of 60～120℃,the effective water diffusion coefficient of ginkgo biloba medicine residue is distributed between 3.39223×10-7～1.10521×10-6,and the drying activation energy is 21.7376 k J·mol-1.The determination coefficient of the Logarithmic model is not less than 0.9992,and the root mean square error and the chi-square test value are not greater than 5.287×10-3 and3.319×10-5,respectively.It is the most suitable mathematical model to describe the hot-air thin-layer drying of ginkgo biloba medicine residue.（2）The unit energy consumption of the main processing links such as drying,pulverizing and pelletizing of ginkgo biloba medicine residue pellet fuel was tested and studied.First,study the influence of different drying temperatures on the energy consumption of ginkgo biloba medicine residue drying;Then,through orthogonal experiments,study the influence of moisture content,screen aperture and spindle speed on pulverizing energy consumption,and analyze the conditions of different moisture content and particle size Energy consumption of pelletizing.Finally,according to the ratio of the calorific value of the prepared pellet fuel to the total processing energy consumption,the optimal processing parameters of the ginkgo biloba medicine residue pellet fuel are determined.The test results show that during drying,the unit drying energy consumption is the lowest at a drying temperature of 110°C;During pulverizing,when the raw material has a moisture content of13%,the screen aperture is 4mm,and the spindle speed of the pulverizer is 4550r/min,the unit pulverizing energy consumption is the lowest;When granulating and forming,the moisture content of the raw material is 16%,and the unit energy consumption is the lowest when the particle size is 4mm.Considering the ratio of the unit calorific value to the total processing energy consumption,the optimal processing parameters of ginkgo biloba medicine residue pellet fuel are:drying temperature 110℃,raw material moisture content16%,screen aperture 3mm,pulverizer spindle speed 4550r/min.Under this process condition,the total processing energy consumption of ginkgo biloba medicine residue pellet fuel is4478.3k J/kg,and the unit calorific value is 17.352.4k J/kg,which meets the national industry technical standards for biomass pellet fuel.（3）The influence of molding parameters on the physical properties of ginkgo biloba medicine residue pellet fuel was studied.First,conduct a single factor test to study the influence of moisture content,particle size and die hole diameter on the density,compressive strength,shear strength,shatter resistance,and water permeability of ginkgo biloba medicine residue pellet fuel;Then,a regression orthogonal test was performed to analyze the primary and secondary order and interaction of the three factors on density,shear strength,and water resistance;Finally,the linear weighted summation of the results of each index is performed to obtain the best shape of the ginkgo biloba medicine residue pellet fuel parameter.The test results show that the moisture content of raw materials has an extremely significant effect on the physical properties of ginkgo biloba medicine residue pellet fuel（<0.05）;The particle size of the raw materials has significant effects on the density,compressive strength,shear strength,and water permeability of the ginkgo biloba medicine residue pellet fuel（<0.05）,but the impact on the crush resistance is not significant（>0.05）;The die hole diameter of the granulator has significant effects on the density,shear strength,shatter resistance,and water permeability of the ginkgo biloba medicine residue pellet fuel（<0.05）,but the impact on the compressive strength is not significant（>0.05）.The primary and secondary order of factors affecting density is die hole diameter,particle size,and moisture content.When the moisture content is 13%,the particle size is 2mm,and the die hole diameter is 4mm,the density of ginkgo biloba medicine residue pellet fuel is the largest;The primary and secondary order of the factors affecting the shear strength is die hole diameter,moisture content,and particle size.When the moisture content is 19%,the particle size is 2mm,and the die hole diameter is 8mm,the shear strength of ginkgo biloba medicine residue pellet fuel is the largest;The primary and secondary order of the factors affecting water permeability is die hole diameter,moisture content,and particle size.When the water content is 13%,the particle size is 4mm,and the die hole diameter is 8mm,the water resistance of Ginkgo biloba dregs pellet fuel is the best.According to the multi-objective planning idea,the linear weighted summation of the results of each index is carried out to obtain the best molding parameters of ginkgo biloba medicine residue pellet fuel:water content of 19%,particle size of 2mm,and die hole diameter of 8mm. |
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