Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass

Jenny Rizkiana,Dwiwahju Sasongko,Ryzka Pranata,Winny Wulandari,Hasna Nisrina Fauzi,A.C Kumoro,Hadiyanto Hadiyanto,W.R.W Daud,S.A Roces,A.W Lothongkum,X Rong,L Yung,M.A Hussain,P.T.S Nam,M.T Phong

doi:10.1051/matecconf/201815603020

Abstract

Coal can be used to produce hydrogen through steam gasification process. Indonesia has abundant coal reserves and thus hydrogen production from coal is very attractive. However, steam gasification of coal usually requires high temperature due to its low volatile content. The use of catalyst, such as alkaline and alkaline earth metal (AAEM) may promote the hydrogen production. AAEM metal can be found in biomass and thus co-gasification of coal and biomass may become the attractive solution as the AAEM may volatilize during gasification and catalyze the coal when it attaches to the coal surface. However, the presence of silicate may decrease catalytic activity of the attached AAEM and thus it needs to be removed by deashing process. This research aims to determine the effect of the solution type, solution concentration, reaction temperature, and reaction time of coal deashing. The results showed that deashing process decreased the ash content of coal to some extent proved by the gravimetric analysis result. The decrease of ash content also affected to the surface morphology of the coal as some pores are formed and thus the surface area of coal increased slightly. The increase of surface area allows more AAEM to be attached to the coal surface so that the coal may become more reactive towards steam gasification.

Highlights

Ash content in coal sample could decrease approximately 20-23% weight compared to the ash content of raw sample by leaching method using HCl
Steel et al did leaching experiments with various temperatures, i.e. 20oC, 70oC, and 100oC. They found that ash content at temperature 20oC and 70oC not much different
This paper has shown that HCl and HF could decrease ash content of coal

Summary

Introduction

92% of Indonesian coals are low rank, such as subbituminous and lignite [1]. Low rank coal has high moisture content and low calorific value. Coal is still widely used in Indonesia as main energy sources because of its low price. Coal is used by burning to produce heat as main energy sources, so it causes bad impact to environment. Gasification is considered as an effective way to utilize coal cleanly [2]

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Conclusion