Analysis of green liquor influence on coal steam gasification process

Abstract

Gasification is a clean and efficient technology with a long history dating up to the 19 th century. The possible application of this process ranges from gas production and chemical synthesis to the energy sector and therefore this technology holds noticeable potential for future applications. In order to advance it, a new efficient approaches for this complex process are necessary. Among possible methods, a process enhancing additives, such as alkali and alkaline earth metals seems to be a promising way of achieving such a goal, but in practice might turn to be a wasteful approach for metal economy, especially in large scale production. This paper shows alkali abundant waste material that are green liquor dregs as a viable substitute. Green liquor dregs is a waste material known for its low potential as a fuel, when used separately, due to its low organic content, but its high ash content that is also abundant in alkali and alkaline earth elements seems to make it a suitable candidate for application in coal gasification processes. The aim of this work is an evaluation of the suitability of green liquor waste to work as a potential process enhancing additive for coal steam gasification process. During the experiment, three blends of hard coal and green liquor dregs were selected, with consideration for low corrosive potential and possibly high catalytic activity. The mixtures were gasified in steam under four different temperatures. Their energies syngas yield, coal conversion degree and energies of activation were calculated with use of Random Pore Model (RPM) and Grain Model (GM) which allowed for their comparison.