Production of High H₂/CO Syngas by Steam Gasification of Shengli Lignite: Catalytic Effect of Inherent Minerals

Abstract

The steam gasification of Shengli lignite (SL-raw) and demineralized samples (SL-HCl and SL-HF) obtained by sequential leaching with hydrochloric acid and hydrofluoric acid aqueous solutions was conducted using fixed-bed microreactor equipment. The high steam gasification rate of Shengli lignite was achieved at a lower temperature range of 616−750°C compared to the demineralized lignite SL-HCl and SL-HF, indicating that the inherent minerals within Shengli lignite had a distinguished catalytic effect on the steam gasification. The initiating temperature for the steam gasification of SL-raw was 616°C, which was about 140°C lower compared to the initiating temperature of demineralized lignite samples SL-HCl and SL-HF at 756°C. On the basis of the very similar characteristics of steam gasification of SL-HCl and SL-HF, it was indeed confirmed that the principal component of inherent minerals that played a catalytic effect on the steam gasification reaction was calcium ion, which can be readily eluted by hydrochloric acid aqueous solution. The natural minerals within SL-raw not only effectively accelerated the reactivity of steam gasification but also significantly enhanced the H 2 production and substantially reduced the formation of CO, especially in the low-temperature range from 616 to 750°C. The optimal performances of steam gasification of Shengli lignite at lower temperatures were majorly attributed to the significant improvement of the water-gas shift (WGS) reaction by the inherent minerals. This study demonstrated that Shengli lignite could be a potential feedstock for the production of H 2 -rich synthesis gas by the steam gasification at the temperatures below 750°C.

The catalytic effect of calcium and potassium on CO 2 gasification of Shengli lignite: the role of carboxyl

“…The reactivity of the gasification of SL + and SL ++ is similar [ 32 ]. Therefore, the metal-cation-doped SL + coal samples were used to investigate the catalytic effect of different metals during CO 2 gasification.…”

Transformation and catalytic effects of sodium during coal pyrolysis

“…The Ca content was much higher than the Na content in the raw coal, while the Mg content was less than half of the Na content. Considering the excellent catalytic abilities of Mg and Ca and their large contents in the raw coal, it was necessary to remove these elements before investigating the effects of Na.…”

Investigate the Adsorption Behavior of CO2on Char–Inorganic Compound Model for Coal Gasification

“…It was reported that Na, Ca, Fe, Mg, Ba, Si, Al, Ti, V, and B affect the reactivity in heat processes such as gasification and coking. − Among them, Na, Ca, Fe, and B were selected as catalyst in our work. The crystal model of inorganic compound was needed to be established because adopted inorganic compound is naturally crystalline.…”

“…Inherent minerals in raw coal are usually considered as a harmful waste and are required to be split before utilization. Fortunately, it was found that those minerals play an important catalytic role for some reaction processes such as carbonization, gasification, and coking. − Further, investigations indicated that alkali, alkaline earth metallic species (K, Na, Ca and Mg), and group VIII transition metals (Fe) are efficiently active for gasification. , Hence, adding alkali metal salts and transition metals was reported to improve the coal gasification process on an industrial scale, which was attributed to their catalytic function . However, other minerals in raw coal such as boron (B), molybdenum (Mo), and titanium (Ti) present the adverse effect on coal gasification .…”