Alkali soil harmfully affects the growth of most vegetation mainly due to its high pH caused by sodium carbonate. Calcium sulfate has been known as a chemical for improving this soil, because calcium ion dissolved from it substitutes sodium ion in the exchange site of the clay in the soil. The object of this research is to investigate an effect of desulfurization gypsum on the growth of wheat on the alkali soil. In the northern part of China, the soil is widely distributed and needed to be improved in order to increase the agricultural products. The use of desulfurization gypsum for the improvement of the alkali soil is paid attention for the possibility to promote the construction of desulfurization units. The experiment on the growth of the wheat was carried out on the soil imported from Shen Yang in China. It showed that 0.5 wt% of desulfurization gypsum provides a greater harvest than the case of the control. According to the benefit estimation with the ratio of 0.5 wt% CaSO4·2H2O, desulfurization units in Paotou in the Inner Mongolia will bring gypsum to 130 thousands of farmers in this area, if they are installed.
A new coal pyrolysis model based on FLASHCHAIN model is proposed to quantitatively estimate the amount of released tar and pyrolytic gases from different kind of coals. The FLASHCHAIN model derived from the molecular structure of coal has been proposed for the rapid pyrolysis by Niksa et al. and can consider the effect of the pyrolysis condition on the products yields. The new model parameters are determined from correlation equations of improved parallel first order reaction model previously proposed by Miura et al. and the ultimate analysis of coal. The simulated results are compared with our experiments on volatile matter and tar yield with various heating rate conditions (10 and 100 K/min) and coals (Witbank, Lusca and Warkworth) The new model can predict well both yields and consider the effect of molecular structure of coal on release rate of volatile matters. The model will be applied to the mathematical mnriellinv of earhnnizatinn nrneess in the irnnmakincr nrneess
Chlorination and volatilization characteristics of minerals in coal ashes were studied for chemical modification of the ash composition and properties. The ash samples were prepared by burning three bituminous coals, a lignite and a brown coal in a muffle furnace at 1088 K (high-temperature ash; HTA) and in an O2 plasma asher (low-temperature ash; LTA). On heating the ashes at 10 K/min to 1273 K in atmospheric chlorine gas flow in a thermobalance reactor, chlorination of minerals was found to take place even without oxygen sink and was followed by vaporization of the metal chlorides formed. Elemental analysis of the original and chlorine-treated HTAs revealed that most of K, Na, Mg and Fe and a portion of Ca were extracted while others such as Si and Al were hardly volatilized. Some pure metal oxides and a carbonate abundant in the ashes were treated at the same conditions. The result showed that Fe2O3 and Fe3O4 were rapidly volatilized in a temperature range of 900 to 1200 K. MgO was slowly but completely volatilized at 1273 K. Chlorination of CaO and CaCO3 occurred at much lower temperatures but vaporization of CaCl2 proceeded very slowly even at 1273 K. Changes in the ash weight with increasing temperature widely varied for the type of the initial ash. The variation was explained on the basis of the initial contents of metal oxides and carbonates. The chlorination treatment resulted in a significant reduction of differences in the mineral compositions, melting point temperatures and acid-base indices of residual solids from HTAs derived from the bituminous coals.
The present paper describes the results of the THF-solubles accumulation phenomenon in chars. The chars obtained from two Japanese bituminous coals, Akabira and Miike coals, were pyrolyzed in a TG and a free fall reactor under a nitrogen stream at atmospheric pressure. The maximum temperature range and heating rates, respectively, were 300-600°C and 3 or 100°C /min in the TG, and were 363-682°C, up to 1.0 × 105°C /min calculated in the free fall reactor. The properties of chars produced by each apparatus were analyzed and compared at the same conversion by THF extraction, H/C ratio and FT-IR. For each coal, rapid pyrolysis (100 and 105°C /min heating rates) allowed the THF-solubles fraction (thought of as heavy primary products) to accumulate in the char as heating rate increased. The maximum yields of THF-solubles in chars also appeared at low conversions, 0.15-0.2 for Akabira coal and 0.08-0.13 for Miike coal. Variations in H/C and Har/Hal ratios were small in this region of low conversion. From these results, we can say that heavy primary products still remain in char particles without secondary reaction.