| The crop stalks are very common waste meterials in our country, and they have lots of merits, reproducity, widely distribution and abound resources, and so on. The application of the bio-mass stalks is very significant to improve the energy structure, guarantee the energy safety and reduce the environmental pollution.In recent ten years, the research on the applicable technologies of bio-mass stalks energy has been developed vigorously. However, the moisture content of crop stalks in the harvesting time is about 50%-70%, so no matter which kind of utilizing method(gasification, liquefaction or solidification etc.)is used, the bio-mass stalks require drying and they can only become useful after the moisture content are reduced to 15% or lower. Therefore, the fast and highly-efficient drying of the crop stalks,which occupy a leading position in the bio-mass energy, was studied as an important part of Research on Pre-processing Technology during Gasification Process of Fluidized Bed for Agricultural Waste", the sub-subject of "Gasified Bio-bass Power Generation Optimized System and Its Model Project", which is the program project of the tenth five-year plan and "863"program.As fluidized-bed dryer has the virtue of the high efficiency in heat transfer, temperature uniformity and good airproof performance, it has been used broadly in chemical engineering, light industry, curatorial industry, foodstuff industry, architectural industry and so on. In the paper various tests were conducted regarding the physical and chemical characteristics, thermogravimetric characteristics, isothermal drying characteristics of the crop stalks and the influence of such characteristics on the drying process is generalizated. On this basis, this thesis chiefly studies the fluidization properties and isothermal drying characterisics of the crape straws with the fluid-bed drying technique. Firstly, the cold fluidization properties tests of the rape straws were conducted in a fluidized bed reactor, and by analyzing the particle diameter and length and the materials height influence the stalks fluidization properties, we get the suitable fluidization particle diameter and critical fluidization velocity of the rape straws. Secondly, the isothermal drying experiments were conducted, by analyzing the experimental datas, we get the isothermal drying curves of diffenert air temperature, air velocity and initial moisture content stalks, and their common features and different features. Furthermore, we use Page equation to simulate and compare the calculated results with experimented datas. By theoretical derivation, we find the mathematic model that fit stalks drying. On this base of qualitative investigation, we adopt the SPSS data analytical software, proceed the test of significance and the analysis of partial correlation on the dependence of the air temperature, air velocity and initial moisture and the drying rate. As a result, we get their quantitative partial correlation coefficients, and the influence on the drying characteristic. This is significant for guiding the industrialized production of stalk drying. |
