Thermo-mechanical Simulations Confirm: Temperature-dependent Mudrock Properties are Nice to have in Far-field Environmental Assessments of Underground Coal Gasification

Otto, Christopher; Kempka, Thomas

doi:10.1016/j.egypro.2015.07.875

Cited by 25 publications

(13 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Data on the carbon content from the ultimate analysis and the carbon content in the tars were provided by Otto et. al and Stańczyk et al [7,9,[18][19][20]. For the four investigated scenarios, the synthesis gas composition most suitable for electricity generation is represented by Scenario II (best case) with COE of 41.3 e/MWh (43% below the worst case).…”

Section: Onshore Ucg-ccgt-ccs Scenariomentioning

confidence: 99%

See 1 more Smart Citation

RETRACTED: Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

Nakaten

Kempka

2017

Energies

Self Cite

View full text Add to dashboard Cite

Underground Coal Gasification (UCG) enables the utilisation of coal reserves that are currently not economically exploitable due to complex geological boundary conditions. Hereby, UCG produces a high-calorific synthesis gas that can be used for generation of electricity, fuels and chemical feedstock. The present study aims to identify economically competitive, site-specific end-use options for onshore and offshore produced UCG synthesis gas, taking into account the capture and storage (CCS) and/or utilisation (CCU) of resulting CO 2 . Modelling results show that boundary conditions that favour electricity, methanol and ammonia production expose low costs for air separation, high synthesis gas calorific values and H 2 /N 2 shares as well as low CO 2 portions of max. 10%. Hereby, a gasification agent ratio of more than 30% oxygen by volume is not favourable from economic and environmental viewpoints. Compared to the costs of an offshore platform with its technical equipment, offshore drilling costs are negligible. Thus, uncertainties related to parameters influenced by drilling costs are also negligible. In summary, techno-economic process modelling results reveal that scenarios with high CO 2 emissions are the most cost-intensive ones, offshore UCG-CCS/CCU costs are twice as high as the onshore ones, and yet all investigated scenarios except from offshore ammonia production are competitive on the European market.

show abstract

Section: Onshore Ucg-ccgt-ccs Scenariomentioning

confidence: 99%

“…Table 1) and coal seam extraction (cf. Table 2) were adapted from the coupled thermo-mechanical 3D UCG model set-up introduced by Otto et al [18] and data elaborated by Otto et al [19,20]. Table 1.…”

Section: Onshore Ucg Technology Implementationmentioning

confidence: 99%

RETRACTED: Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

Nakaten

Kempka

2017

Energies

Self Cite

View full text Add to dashboard Cite

show abstract

“…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]. With focus on the growing public debate on gas leakage affiliated with organic groundwater pollution risks as well as general tar plugging problems, a key future UCG by-product challenge thus lies in better tar production control and aligned organic pollutant minimization in UCG gases [20][21][22][23].…”

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

Self Cite

View full text Add to dashboard Cite

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

show abstract

“…The latter may affect the potential flow of gasification oxidants and products as well as of groundwater present in the reactor vicinity, potentially determining the gasification process efficiency and environmental impacts. Porosity and permeability changes in the vicinity of UCG reactors can be expressed as function of volumetric strain increment as shown in our previous studies [31,32]. For the assessment of permeability changes, normalized permeabilities with an initially uniform distribution in the model were applied, while average rock-specific porosities, depending on the present lithology were derived from literature and assigned to the respective model layers (Table 3).…”

Section: Permeability Distribution In the Rocks Surrounding The Ucg Cmentioning

confidence: 99%

“…In order to enhance the features of a 3D model and to apply the model for the assessment and prediction of UCG performance considering thermo-mechanical impacts, it is imperative to incorporate coal seam properties and geology of the target site into the model. Hereby, our previous findings [31,32] emphasize that model simplifications with regard to the consideration of thermo-mechanical parameters in far-field numerical models can significantly reduce the computational time, while preserving the validity of the numerical results.…”

Section: Introductionmentioning

confidence: 99%

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

et al. 2016

Self Cite

View full text Add to dashboard Cite

Underground coal gasification (UCG) has the potential to increase worldwide coal reserves by utilization of coal deposits not mineable by conventional methods. This involves combusting coal in situ to produce a synthesis gas, applicable for electricity generation and chemical feedstock production. Three-dimensional (3D) thermo-mechanical models already significantly contribute to UCG design by process optimization and mitigation of the environmental footprint. We developed the first 3D UCG model based on real structural geological data to investigate the impacts of using isothermal and non-isothermal simulations, two different pillar widths and four varying regional stress regimes on the spatial changes in temperature and permeability, ground surface subsidence and fault reactivation. Our simulation results demonstrate that non-isothermal processes have to be considered in these assessments due to thermally-induced stresses. Furthermore, we demonstrate that permeability increase is limited to the close reactor vicinity, although the presence of previously undetected faults can introduce formation of hydraulic short circuits between single UCG channels over large distances. This requires particular consideration of potentially present sub-seismic faults in the exploration and site selection stages, since the required pillar widths may be easily underestimated in presence of faults with different orientations with respect to the regional stress regime.

show abstract

Thermo-mechanical Simulations Confirm: Temperature-dependent Mudrock Properties are Nice to have in Far-field Environmental Assessments of Underground Coal Gasification

Cited by 25 publications

References 24 publications

RETRACTED: Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

RETRACTED: Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

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

Fault Reactivation Can Generate Hydraulic Short Circuits in Underground Coal Gasification—New Insights from Regional-Scale Thermo-Mechanical 3D Modeling

Contact Info

Product

Resources

About