沙柳生物质燃料颗粒致密成型粘结机理研究

东北地区主要的农业废弃物玉米秸秆焚烧严重，造成环境污染，其合理消纳是亟需解决的问题。基于此，该文利用微型流化床与过程质谱联用仪研究在床温分别为550、600、650、700及750 ℃添加Na2CO3和NaCl的玉米秸秆热解气相产物（CO、CO2、CH4、H2）的析出特性，并采用等温模型拟合法计算了单组分气体产物生成反应的动力学参数。结果表明：随着温度的升高，4种热解气体产物的释放强度均有所增大，其中CO的变化程度最大。同时，添加钠盐后，各种气体释放起始时间差逐渐减小，说明钠盐促进了热解反应的进行。其中，添加Na2CO3后热解产生的CO、CO2和CH4的速率明显变快，表明其对含炭气相组分的生成具有明显促进作用。而添加NaCl后H2的生成速率明显加快，说明NaCl对H2生成具有选择性催化作用。此外，秸秆热解中不同气相产物生成反应活化能的计算结果也证实了上述结论。该文通过热解制备可燃气的方式以期为玉米秸秆的处理提供参考。

Bonding mechanism of dense forming of salix biomass fuel particles

Abstract: The biomass fuel is defined as burning biomass materials as fuel, which has the characteristics of wide distribution, reproducible and pollution-free. This fuel has become so important in the field of energy resources that the corresponding research has attracted extensive attention from both academia and industry. In order to improve technology of this fuel the physical and chemical properties of internal lignin during the dense forming process of Salix psammophila and its effect on fuel formation was researched in this paper, and a detailed discussion about its bonding mechanism of dense forming was presented. The main research process of this paper could be summarized as: Firstly, by using amporphous cell and forcite related blocks of software Materials Studio 2017, the lignin molecular fragments with different water content were created ( the lignin molecular chain was 10), in the procedure of creation, the initial temperature was 298 K, the pressure was standard atmospheric pressure, and the number of configuration was 2; Furthermore, in conditions of different moisture contents, pressures and temperatures, the molecular dynamics simulation calculation and related property prediction of lignin molecular fragment were conducted, and the diffusion ability of lignin molecules could be investigated by the distribution function in research of the latter, though analysis and calculation, the intervals of lignin molecule strong peak were determined; At last, for guaranteeing the rationality and reliability of bonding mechanism, and better observing the binding mode between particles, the hot pressing forming test of Salix biomass fuel was carried out with reference to the simulation conditions and the obtained results, the characteristics and microscopic morphology of the formed fuel were analyzed with the tested sample. The simulations and test illustrate that: in moisture content of 8%, 11%, 14%, 17%, the glass transition temperature (Tg) of Salix lignin successively were 410, 392, 381 and 376 K. Although the diffusion ability of lignin molecules increased with the increasing temperature, increased first and then decreased with the increase of pressure and water content, and under the case of the pressure was 40 MPa and the water content was 14%, the diffusion ability reached the maximum value. When the water content, the pressure and the temperature were 14%, 40 MPa and 380 K, respectively, water molecules and lignin molecules could form hydrogen bonds, and the main source was predicted to be the interaction between water molecules and cyclic or acyclic hydroxyl groups. Based on the above analysis, the relevant characteristics of the molding fuel was studied, and the result showed that: Firstly, the prediction of properties was more accurate, such as salix lignin Tg; Secondly, though proper moisture and temperature could reduce the molding power consumption and relaxation ratio, the both were not suitable excess high; Thirdly, in vertical direction, under the action of viscous fluid, the fuel interior particles were solidified together superimposed by the method of viscous fluid; Fourthly, in horizontal direction, the main binding modes of fuel interior particles were tiling, lapping and fitting, and had a significant mesh-like structure and this structure related to the rich fibers contained in the sand willow wood, and could effectively enhance the mechanism strength of the particles.