A review on moisture re-adsorption of lignite treated using different drying techniques

Abstract

Lignite has great potential for use as one of the major sources for both energy and chemical feedstock. However, its high moisture content extremely restricts its use. The moisture re-adsorption of the dehydrated lignite has been studied increasingly in recent years. This review focuses on the issue of the high moisture re-adsorption capacity of lignite dehydrated using various drying techniques. Experimental and simulative studies on the effects of oxygen-containing functional groups, pores, and other factors on the moisture re-adsorption of the dehydrated lignites from different countries or districts and exploratory work on inhibiting the moisture re-adsorption of the dehydrated lignite are reviewed in detail. Of particular interest is a proposal for a mechanism of moisture re-adsorption on the dehydrated lignite. Additionally, future investigations on inhibiting the moisture re-adsorption of the dehydrated lignite are advised.

Keywords:

• Lignite
• moisture re-adsorption
• oxygen-containing functional groups
• pores

Disclosure of Interest Statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This work was supported by National Natural Science Foundation of China (No. 21776002), Natural Science Foundation of Anhui Provincial Education Department (Nos. KJ2019A0076 and KJ2017A056), Natural Science Foundation of Anhui Province (2008085QB87 and 1708085QB33), Science and Technology Major Projects of Anhui Province (17030901086), Innovation Project of Overseas People of Anhui Province (no No.), and Anhui Province Key Laboratory of Coal Clean Conversion and High Valued Utilization, Anhui University of Technology (CHV-19-04).