Title: Comparative Evaluation of Microwave and Conventional Gasification of Different Coal Types: Experimental Reaction Studies

Abstract

Here, effects of gasifier conditions (microwave or conventional) on the gasification characteristics of four different types of coal are evaluated by analysis of gaseous species generated during pyrolysis and gasification reactions. Four different coal samples are tested: a lignite (Mississippi), a low-ash subbituminous (Wyodak), a high-ash subbituminous (Usibelli), and a low volatile bituminous (Pocahontas #3). Gas composition, overall yields, carbon conversion efficiency, and cold gas efficiency are evaluated to compare gasification reactivity of the different coal types under microwave and conventional heating. During microwave pyrolysis (Ar atmosphere), greater selectivity of syngas species (H2 + CO) and greater overall non-condensable gas yields are observed, compared to conventional pyrolysis for all coals tested. The high yield of syngas during microwave pyrolysis is attributed to primary pyrolysis gases subsequently gasifying the char of the same sample to produce greater amounts of H2 and CO. During microwave gasification (CO2 atmosphere), selective heating and formation of hotspots within the coal enable the reverse Boudouard reaction to occur at a low bulk gasification temperature of 700 °C, which is less favorable under thermal gasification at this temperature. Yields of syngas are much higher under microwave gasification of all coals. Carbon conversion is found to have amore » linear correlation with volatile matter of the parent coal. Carbon conversion and cold gas efficiency are highest for coals gasified under microwave irradiation, and gasification reactivity of the four coals was determined to be dependent on the coal type.« less

Authors:

Ellison, Candice ^[1]; Abdelsayed, Victor ^[1]; Smith, Mark ^[1]; Shekhawat, Dushyant ^[1]

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+ Show Author Affiliations

1. National Energy Technology Lab. (NETL), Morgantown, WV (United States)

Publication Date:

Thu Apr 07 00:00:00 EDT 2022

Research Org.:

National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)

Sponsoring Org.:

USDOE Office of Fossil Energy (FE)

OSTI Identifier:

1868085

Alternate Identifier(s):

OSTI ID: 2319054

Grant/Contract Number:  

89243318CFE000003

Resource Type:

Accepted Manuscript

Journal Name:

Fuel

Additional Journal Information:

Journal Volume: 321; Journal Issue: None

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

01 COAL, LIGNITE, AND PEAT