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Wang G.,The Chinese Academy of Agricultural Engineering | Huo L.,The Chinese Academy of Agricultural Engineering | Zhao L.,The Chinese Academy of Agricultural Engineering | Yao Z.,The Chinese Academy of Agricultural Engineering | Meng H.,The Chinese Academy of Agricultural Engineering
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

Research and application on screening in China are mainly focused on coal, metallurgy, chemicals, building materials, and so on, only a few researches on the field of biomass energy. Biomass energy research is mainly focused on raw material obtaining and process, which can't solve small impurity removal problems after straw harvest. Therefore, this article carried out the comparative tests of thermal characteristics on corn stover feedstock with different sizes, studied the impact of dust and other fine particulate matter on raw materials quality of corn stover, and analyzed the proportion of impurities with different particle sizes and their impacts on raw materials; the best sieve size range of raw materials was put forward so as to improve the purity of raw materials, and optimize the impurity screening equipment connecting between mill and molding machine. A series of experiments were done. At first, different corn straw materials, which were less than 10 mm particle size, should be divided into 9 size classes through sieve analysis; secondly, different size particles as material were utilized for thermal characteristic measurement and sedimentation experiments; thirdly, the proportion and the effect of fine particulate impurities in different corn straw materials were analyzed; at last, dust contents of 2 kinds of materials whose sizes were less than 0.2 and 0.33-0.2 mm exceeded 50%, and the quantity represented 3.39% of the total sum of such 2 kinds of materials. Therefore, the best suitable material size range is less than 0.33 mm compared to the other straw materials. Through the results of above analysis and a large number of reference documents, the sieve in this study were modified and processed from the former drum sieve. The structure of sieve also could be optimized, and its parameters were as follows: Sieve tube length was 1000 mm, screen cylinder diameter was 500 mm, screen cylinder inclination angle was 10°, rotation speed was 34 r/min, and sieve hole diameter was 0.33 mm. The comparative experiments and economic analysis based on this equipment were conducted. The results showed that the volatile matter and calorific value of pellets through the sieve process were improved significantly, and the ash content was reduced by 25.21%, which greatly declined the material's molding wear risks to briquette machines and slagging risks to combustion devices. The economic value of this briquetting fuel increased to 563.5 yuan/t, which increased by 6.91%. The method that the sieve is considered as the first phase at the briquette forming can improve the purity of the material, and ensure the quality of fuel formed from corn straw. This thesis is expected to propose a screening technology and equipment suitable for Chinese large-scale production of biomass briquettes, to provide technical support for cleaning process, and to provide an important basis of parameters for the energy utilization of the straw. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.


Huo L.,The Chinese Academy of Agricultural Engineering | Huo L.,China Agricultural University | Tian Y.,The Chinese Academy of Agricultural Engineering | Meng H.,The Chinese Academy of Agricultural Engineering | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

Raw material and kibbling material and biomass pellet were observed by microscopy in order to study the surface morphology mechanism in this paper. The biomass pellets which the raw material were corn straw and sawdust were densified by pellet mill, and the combination style of micro morphology and particles of different raw material and material at diverse stages was studied. The results showed that pellet mill was intermittent compression during production process, and surface morphology mechanism of biomass pellet was layered compressed where the layer spacing was from 25 to 40 μm. The pellet was divided into three layers from the cross section, including the center layer particles as "flat" and the transition layer particles as deformed, and the surface particles as "vertical." Compared to sawdust pellets, the particle density of corn straw pellets was smaller under the same extrusion pressure. So this study will provide important theory basis to design the biomass molding equipment.


Huo L.,The Chinese Academy of Agricultural Engineering | Huo L.,China Agricultural University | Tian Y.,The Chinese Academy of Agricultural Engineering | Meng H.,The Chinese Academy of Agricultural Engineering | And 2 more authors.
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2011

This study aimed to investigate energy efficiency and greenhouse gas emission. Utilizing system BSAS, using corn stalk as raw material in Beijing Area, It was LCA of densified biofuel and the results showed that the Process of LCA earned 13243.5 MJ/t net energy and energy input-output ratio has been arrived about 10.8, among them, planting phase, processing phase and corn stalk transportation were high-overall energy consumption, and case percentages were 58.65%, 24.23% and 12.58%. Greenhouse gas emission was 11.12 g/MJ, only one nine. Speak volumes for densified biofuel have benefit of energy saving and emission reduction, it provide evidence for national policy making.


Huo L.,The Chinese Academy of Agricultural Engineering | Huo L.,China Agricultural University | Zhao L.,The Chinese Academy of Agricultural Engineering | Tian Y.,The Chinese Academy of Agricultural Engineering | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Biomass resources such as agricultural and forestry wastes are very rich in China. Biomass can be compressed into a pellet and used instead of coal for heating, electricity, etc. Currently, the use of biomass pellets is being rapidly promoted. Not only can they be used for home cooking, heating, they can also be used as high-quality fuel for industrial boilers and power plants. Compared with coal, the greenhouse gas emissions of biomass pellet less than 1/9 of the coal, so these pellets have environmental benefits. This thesis research is about a biomass pellet molding viscoelastic constitutive model. The six kinds of biomass pellet raw materials which include corn straw, peanut shell, wheat straw, soybean straw, cotton straw and sawdust were the study objects densified by a 485 type roll pellet mill to analyze the stress change rules during the densifying process and measure the single feedstock of a biomass pellet by microscope in this paper. The densifying process of biomass pellets after feedstock was simulated and studied through a universal testing machine and self-made compress fixture when this is no raw material feed. The constitutive model was built for biomass pellets with viscoelastic theory to present the densifying mechanism for biomass pellets from the standpoint of mechanics, and the maximum stress and the energy consumption of the densifying process of the different species of raw material were compared and studied. The results showed that the viscoelastic constitutive model can be used to describe the densifying process of biomass pellets. A constitutive model of stress to strain can be adopted at the densifying process phase, and stress to time at stress relaxation phase. The fitting of a model curve is perfect and all coefficients of association are higher than 90%. Basically, the single feedstock for different raw material is the same, which is approximate 150 to 160 mg, while the densifying pellet density varies from each other which can be 1030, 1170, 1010, 1060, 1185, 1240 kg/m3 for corn straw, peanut shell, wheat straw, soybean straw, cotton straw and sawdust respectively. The maximum stress for the six kinds of raw material is that cotton straw and sawdust is higher, approximately 67 to 77 MPa, and the other 4 are between 45 and 55 MPa. The energy consumption of sawdust is the highest, which is 158 J/g, followed by cotton straw 91.4 J/g, peanut shell 86.9 J/g and soybean straw 65.5 J/g, and wheat straw and corn straw is much lower, which is 56.2 J/g and 45.1 J/g respectively. The biomass pellets' density is higher, and the energy consumption is higher which can be increased as fast as the increasing of density. This study results provide an important theoretical basis to solve the problem of the high-energy consumption of biomass pellets densifying manufacture, and ease the wear and short life of the key components of pellet mills.

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