Recent development on underground coal gasification and subsequent CO 2 storage

Yang, Dongmin; Koukouzas, Nikolaos; Green, Michael; Sheng, Yong

doi:10.1016/j.joei.2015.05.004

Cited by 71 publications

(35 citation statements)

References 26 publications

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“…Various factors during the in-situ UCG reactor operation often hamper a continuously stable process performance (e.g. water ingress, heat losses), in consequence partially leading to lower synthesis gas qualities and undesired hazardous byproducts [1,3,[8][9][10][11][12][13][14]. Pollutant charged gas leakage from the UCG reactor due to roof rock failure as a thermo-mechanical response of in-situ pressure and temperature conditions recently marks one of the most severe potential environmental impacts [1,6,[15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Innovative thermodynamic underground coal gasification model for coupled synthesis gas quality and tar production analyses

Klebingat

Kempka

Schulten

et al. 2016

Fuel

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Originally published as:Klebingat, S., Kempka, T., Schulten, M., Azzam, R., Fernández-Steeger, T. M. (2016): Innovative thermodynamic underground coal gasification model for coupled synthesis gas quality and tar production analyses. Underground Coal Gasification, Thermodynamic model, Synthesis gas quality, Tar production, Environmental impacts 2 ABSTRACT Underground Coal Gasification (UCG) technology is steadily improving due to high scientific and industrial efforts in currently over 14 countries worldwide. A fundamental UCG objective refers to syngas production for multiple end-uses, accompanied by environmental impact mitigation focusing contaminant reduction. In terms of this topic, the control of groundwater quality endangering tars has been a key problem rarely addressed in UCG publications so far.Considering UCG main sub-processes, operating parameters and tar spectrum knowledge

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Section: Introductionmentioning

confidence: 99%

Innovative thermodynamic underground coal gasification model for coupled synthesis gas quality and tar production analyses

Klebingat

Kempka

Schulten

et al. 2016

Fuel

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“…Many efforts have been undertaken towards understanding the complex and strongly coupled thermo-hydro-mechanical processes in UCG [16,26,[32][33][34][35][36]. Numerical modeling has been an important methodology to study these processes in view of UCG performance and sustainability.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Otto

Kempka

2017

Energies

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Underground coal gasification (UCG) converts coal to a high-calorific synthesis gas for the production of fuels or chemical feedstock. UCG reactors are generally operated below hydrostatic pressure to avoid leakage of UCG fluids into overburden aquifers. Additionally, fluid flow out of and into the reactor is also determined by the presence of the steam jacket, emerging in close reactor vicinity due to the high temperatures generated in UCG operation. Aiming at improving the understanding of the substantial role of the steam jacket in UCG operations, we employ numerical non-isothermal multiphase flow simulations to assess the occurring multiphase fluid flow processes. For that purpose, we first validate our modeling approach against published data on the U.S. UCG field trials at Hanna and Hoe Creek, achieving a very good agreement between our simulation and the observed water balances. Then, we discuss the effect of coal seam permeability and UCG reactor pressure on the dynamic multiphase flow processes in the reactor's vicinity. The presented modeling approach allows for the quantification and prediction of time-dependent temperature and pressure distributions in the reactor vicinity, and thus steam jacket dynamics as well as reactor water inand outflows.

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“…Recently, several researchers have investigated the clean utilization of coal in the underground coal gasification [6], focusing on the electrical power generation. Prabu and Jayanti [7] proposed a process for coupling UCG with a solid oxide fuel cell (SOFC), combined with CCS.…”

Section: Introductionmentioning

confidence: 99%

Energy and exergy analysis of alternating injection of oxygen and steam in the low emission underground gasification of deep thin coal

et al. 2017

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• We model UCG process with alternating injection of steam/oxygen.• We used exergy analysis to investigate the practicality of the process.• We show that the alternating injection UCG is practical at low pressure.• Zero emission conversion of coal is not currently practical.• Co-injection of steam/oxygen results in a higher recovery of coal. A R T I C L E I N F O Keywords:Underground coal gasification Alternating injection Exergy analysis Carbon capture and storage A B S T R A C TRecent studies have shown that by coupling the underground coal gasification (UCG) with the carbon capture and storage (CCS), the coal energy can be economically extracted with a low carbon footprint. To investigate the effect of UCG and CCS process parameters on the feasibility of the UCG-CCS process, we utilize a validated mathematical model, previously published by the same authors, that can predict the composition of the UCG product, temperature profile, and coal conversion rate for alternating injection of air and steam for unmineable deep thin coal layers. We use the results of the model to conduct an energy and exergy analysis of the UCG process. We study the effect of various process parameters on the efficiency of the UCG process, the zeroemission recovery factor of coal, and the total CO 2 emission of the process. Moreover, we compare the alternating injection of air/steam with the injection of an air and steam mixture.Exergy analysis shows that the alternating injection of air/steam describes a practical process for UCG at low pressure. However, injecting a mixture of steam and oxygen results in a practical recovery factor of coal higher than the alternating injection process. Additionally, we show that the zero-emission conversion of unmineable deep thin coal resources in a coupled UCG-CCS process, that is not practical with the current state of technology, can be realized by increasing the energy efficiency of the carbon dioxide capture process.

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Recent development on underground coal gasification and subsequent CO 2 storage

Cited by 71 publications

References 26 publications

Innovative thermodynamic underground coal gasification model for coupled synthesis gas quality and tar production analyses

Innovative thermodynamic underground coal gasification model for coupled synthesis gas quality and tar production analyses

Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Energy and exergy analysis of alternating injection of oxygen and steam in the low emission underground gasification of deep thin coal

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