To understand the behavior of the entrained-flow gasification of organic wastes, high calorie value polypropylene (PP) and low calorie value polyethylene terephthalate (PET) were gasified in a single nozzle type Drop Tube Furnace (DTF). In a small scale of gasifier, it is very difficult to obtain as high temperature as 1, 300°C with a low oxygen-carbon molar ratio as being done in larger scale than pilot plants, and it is necessary to operate in high oxygen-carbon molar ratio in order to maintain the reaction temperature 1, 300°C because the heat loss becomes significant in comparison with heating load in the furnace. When methane gas was introduced as an auxiliary fuel under the low oxygen-carbon molar ratio, the reaction temperatures was achieved over 1, 300°C and higher carbon gasification conversion than 80% was attained. The composition of the main gas produced by gasification was correlated by the shift reaction equilibrium at the temperature above 1, 250°C. Then the equilibrium constant, which was almost independent of the temperature in the range, could be approximated about 0.85.
Research on fluoride emission from coal combustion is important to solve a serious fluoride pollution problem. Occurrence mode and behaviors of fluoride during coal combustion were investigated. XRD and XPS analysis showed that fluorides in chinese coal existed mainly as -CF2-, muscovite and apatite. Coal pyrolysis and combustion were carried out by TG-MS. HF was found to be released from both coal pyrolysis and combustion. Experimental result under different combustion conditions showed that fluoride content in flue gas and particles increased with increase in oxygen concentration or temperature, while fluoride content in residue decreased with it.
Activated carbon from larch wood (LW) was prepared in a batch-type fluidized reactor operated at 1, 123K, and its chemical and physical properties, including adsorption capacity, were measured to compare with those of commercial activated carbons obtained from coal and coconut shell. According to pore size distribution measurement, the LW activated carbon had a large proportion of pores with more diameter than 0.6 nm. Adsorption capacity tests with toluene, methylene blue, agricultural medicines and humic substance indicated that the LW activated carbon was equal or superior to the coal and the coconut carbons. Bulk density and hardness for the former carbon were, however, smaller than those for the latter two. For improving these properties, the larch wood was pulverized and then molded by compression prior to carbonization-activation. The pretreatment enabled the production of a general-purpose granular activated carbon.