Influence of coal properties on the CO₂ adsorption capacity of coal gasification residues

Abstract

Post-underground coal gasification (UCG) sites hold attractive prospects for geological storage of carbon dioxide. For the successful commercial implementation of UCG with carbon capture and storage (CCS), site-selection is crucial, and a careful techno-economic feasibility analysis is essential to systematically assess the site related parameters aside from evaluating the environmental risk. This study is related to one of the important aspects of site selection-the coal type. Specifically, this work investigates the influence of coal properties and gasification conditions on the adsorption capacities of CO 2 on gasified coal chars. For this purpose, four coals of diverse ranks varying from lignite to bituminous were selected and subjected to CO 2 gasification at atmospheric pressure for 10 min at 800, 900, and 1000°C under a low heating rate of 5°C/min. Subsequently, the gasified chars, as well as the raw coals, were tested for their adsorption capacity in a purpose built volumetric adsorption apparatus at 45.5°C and pressures up to 90 bar. Also, complementary coal and char analysis were carried out for determining the surface area, pore size distribution, and surface morphology. The CO 2 storage capacity was observed to be a strong function of the coal properties and gasification conditions. Among the samples examined, the highest adsorption capacity was observed for chars of the sub-bituminous coals. The CO 2 adsorption capacity at 80 bar and 45.5°C on the sub-bituminous char samples was 2.08, 2.43, and 1.95 mmole/g that were prepared at 800, 900, and 1000°C, respectively. The experimental adsorption isotherms were fitted to the Dubinin-Radushkevic (DR) and the Dubinin-Astakhov (DA) models. 322

A study of dynamic adsorption of propylene and ethylene emitted from the process of coal self-heating

“…The tendency of gaseous components of mine air to amass on the surface of coal has been previously investigated by means of determining maximum adsorption capacity of coal in relation to single fire gases using the static adsorption technique 14–17 . It has been reported that the contact of gaseous products of the thermal oxidation reaction of coal with an adsorbent such as coal can effectively cause their adsorption in various amounts.…”

Development and application of transient gas‐liquid two‐phase flow model considering sudden density change

“…It is directly related to safety and efficiency, and also to the success of drilling operations. [1][2][3] In order conduct safe drilling for a narrow pressure window in deepwater, research institutions and scholars studied several dual-gradient drilling technologies, such as dual-gradient drilling with light medium (gas, hollow sphere), 4 submarine pump lifting drilling, 5,6 mud cap control drilling, 1,7,8 and deepwater multi-gradient drilling, 9 while developing corresponding core technologies, matching equipment, and drilling theories. In recent years, based on the idea of injecting a light medium (gas, hollow sphere) into the annulus to realize dual-gradient drilling, a new deepwater dual-gradient drilling technology based on downhole separation was developed and a new downhole cyclone separator was designed.…”

“…Narrow pressure margins are a significant factor during deepwater drilling. It is directly related to safety and efficiency, and also to the success of drilling operations . In order conduct safe drilling for a narrow pressure window in deepwater, research institutions and scholars studied several dual‐gradient drilling technologies, such as dual‐gradient drilling with light medium (gas, hollow sphere), submarine pump lifting drilling, mud cap control drilling, and deepwater multi‐gradient drilling, while developing corresponding core technologies, matching equipment, and drilling theories.…”

Microbial degradation of organic pollutants in groundwater related to underground coal gasification

“…Compared with surface gasifier, the cost of syngas produced by UCG is 1/2 to 1/4 of that produced by surface gasifier, 13 the cost of natural gas substitutes produced by UCG is lowered by 10%-18% and the cost of power generation reduces by 27%. 15 Based on the above mentioned benefits, UCG is regarded as one of the most innovative technologies associated with the exploitation of coal deposits. 15 Based on the above mentioned benefits, UCG is regarded as one of the most innovative technologies associated with the exploitation of coal deposits.…”

“…14 Post-UCG sites hold high potential for carbon capture and storage (CCS). 15 Based on the above mentioned benefits, UCG is regarded as one of the most innovative technologies associated with the exploitation of coal deposits. 16 Since the UCG process is conducted in underground coal seams, the produced coal gas together with organic pollutants and heavy metal vapours may migrate to aquifer through the pores and cracks in surrounding rocks and pollute the groundwater in aquifer.…”