Underground Coal Gasification with Extended CO2 Utilization - An Economic and Carbon Neutral Approach to Tackle Energy and Fertilizer Supply Shortages in Bangladesh

2017

Energies

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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.

Section: Ammonia Production Energy Balancementioning

confidence: 99%

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

Nakaten

2017

Energies

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“…Underground Coal Gasification provides a promising technical and economic potential to solve current long-term power supply conflicts worldwide by controlled in-situ conversion of otherwise non-mineable coal reserves [1][2][3][4][5][6][7]. While the technique itself is a rather simple concept in theory, experience from major international field trials over the last decades shows its control in practice is much more complicated.…”

Section: Introductionmentioning

confidence: 99%

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

Klebingat

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

“…The resulting high-calorific synthesis gas can be applied for fuel production, electricity generation or chemical feedstock production [1][2][3][4][5][6][7][8][9]. Apart from its high energetic and economic potential [10][11][12][13][14], UCG may cause environmental impacts such as ground subsidence and groundwater pollution [8,9,[15][16][17]. In order to completely avoid or significantly mitigate these potential environmental concerns, the UCG reactor is generally operated below hydrostatic pressure to hinder the outflow of UCG process fluids into adjacent aquifers [8,18,19].…”

Section: Introductionmentioning

confidence: 99%

Thermo-Mechanical Simulations of Rock Behavior in Underground Coal Gasification Show Negligible Impact of Temperature-Dependent Parameters on Permeability Changes

Otto

2015

Energies

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Abstract:A coupled thermo-mechanical model has been developed to assess permeability changes in the vicinity of an underground coal gasification (UCG) reactor resulting from excavation and thermo-mechanical effects. Thereto, we consider a stepwise UCG reactor excavation based on a pre-defined coal consumption rate and dynamic thermal boundary conditions. Simulation results demonstrate that thermo-mechanical rock behavior is mainly driven by the thermal expansion coefficient, thermal conductivity, tensile strength and elastic modulus of the surrounding rock. A comparison between temperature-dependent and temperature-independent parameters applied in the simulations indicates notable variations in the distribution of total displacements in the UCG reactor vicinity related to thermal stress, but only negligible differences in permeability changes. Hence, temperature-dependent thermo-mechanical parameters have to be considered in the assessment of near-field UCG impacts only, while far-field models can achieve a higher computational efficiency by using temperature-independent thermo-mechanical parameters. Considering the findings of the present study in the large-scale assessment of potential environmental impacts of underground coal gasification, representative coupled simulations based on complex 3D large-scale models become computationally feasible.