Experimental Investigation On Disposal Of Waste Plastics With Coking Process

Nowadays, the cycle of manufacturing and consuming plastic materials has resulted in a serious environmental and economic problem in the world, that is, 'white pollution'. For this reason, disposal on waste plastics has become of increasing concern and various development efforts for waste plastics recycling have been made. Disposal of waste plastics by coking process is an alternative approach conserving both material and energy, where waste plastics are thermally decomposed with coal in high-temperature reducing atmosphere in the coke oven chamber and converted to coke, tar and coke oven gas. In the article, through experiments of thermal balance, thermogravimetry-fourier transform infrared spectrometer (TG-FTIR), 2kg experimental coke-oven, 200kg experimental coke-oven and 4# commercially industrial coke-oven of Shougang group, the co-coking of waste plastics from Beijing municipal solid waste and blend coal from Shougang coking plant were investigated from fundamental theory to industrial application. And then, based on them, the article developed a new disposal on waste plastics by the traditional coking process in China, which could not only increase the ratios of waste plastics added into coke-oven, but also improve the quality of coke from co-coking if the waste plastics addition was limited to a certain ratio. The new technology has been proved not only economically and environmentally friendly but also has notably industrial application to deal with 'white pollution'.The experiments and corresponding conclusion obtained in this dissertation are summarized as follows:1. Thermo-gravimetric behavior of waste plastics (WP), blend coal (BC) and their mixtures in different mixing ratios and different mixing ways were respectively studied during pyrolysis by using a thermal balance. The results showed that:WP and BC showed distinct weight loss steps during pyrolysis, which obviously attributed to the difference between their molecular structures. The pyrolysis behavior of WP was quick and the temperature range of pyrolysis was narrow. But for BC, the pyrolysis behavior was slower and the temperature range was relatively wider. There was an overlapped decomposition temperature region during the pyrolysis of WP and BC respectively. Then, the synergism between them occurred during co-pyrolysis, and in the article, the new idea and formulas of synergism strength were proposed to describe it, as . Beside these, the results also indicated that the thermo-gravimetric behavior and pyrolitic kinetics were closely relative to the mixing ratios and mixing ways of waste plastics and blend coal. Particularly, the excellent coke would be obtained if WP pre-melted in coal firstly before co-coking with BC, which would be further investigated in 2kg and 200kg experimental coke-oven.