Prediction of feasible synthesis gas compositions at three European coal deposits

<p>In the present study, we apply our validated stoichiometric equilibrium model [1], based on direct minimisation of Gibbs free energy, to predict the synthesis gas compositions produced by in-situ coal conversion at three European coal deposits. The applied modelling approach is computationally efficient and allows to predict synthesis gas compositions and calorific values under various operating and geological boundary conditions, including varying oxidant and coal compositions. Three European coal deposits are assessed, comprising the South Wales Coalfield (United Kingdom), the Upper Silesian Coal Basin (Poland) and the Ruhr District (Germany). The stoichiometric equilibrium models were first validated on the basis of laboratory experiments undertaken at two different operating pressures by [2] and available literature data [3]. Then, the models were adapted to site-specific hydrostatic pressure conditions to enable an extrapolation of the synthesis gas composition to in-situ pressure conditions. Our simulation results demonstrate that changes in the synthesis gas composition follow the expected trends for preferential production of specific gas components at increased pressures, known from the literature, emphasising that a reliable methodology for estimations of synthesis gas compositions for different in-situ conditions has been established. The presented predictive approach can be integrated with techno-economic models [4] to assess the technical and economic feasibility of in-situ coal conversion at selected study areas as well as of biomass and waste to synthesis gas conversion projects.</p><p><span>[</span><span>1] </span><span>Otto, C.; Kempka, T. Synthesis Gas Composition Prediction for Underground Coal Gasification Using a Thermochemical Equilibrium Modeling Approach. </span><em><span>Energies</span></em> <span><strong>2020</strong></span><span>, </span><em><span>13</span></em><span>, 1171.</span></p><p>[2] Kapusta et al., 2020</p><p>[3] Kempka et al., 2011</p><p>[4] Nakaten and Kempka, 2019</p>

Influence of coal properties on coal conversion processes-coal carbonization, carbon fiber production, gasification and liquefaction technologies: a review

Coal due to its relatively large quantities and wide distribution worldwide has generated renewed interest in research and development with the aim of establishing coal conversion technologies that are technically reliable, environmentally and economically feasible. It has proved to be a prominent energy source in emerging markets with increasing energy demand by accounting for the largest increase in the demand of energy amongst all other energy sources. Furthermore, with its higher mesophase content, coal tar is an appropriate raw material for precursors in the production of carbon fiber. However, whenever a material is put to use, it is important to be able to associate its properties to the behavioral characteristics during a conversion process so as to have a basis for opting for the material in a given process or adjusting the operating conditions in order to optimize the material utilization. Therefore, as with any other material, it is important to be able to relate the properties of coal to its utilization. A review was carried out on the influence of coal properties on four main utilization technologies: gasification, carbonization, liquefaction and carbon fibre production. Among several properties rank, type, mineral matter content, distribution of trace elements, structural composition and pore structure were found to be most influential on the behavior of coal during conversion processes.

The Effectiveness of Reactive Materials for Contaminant Removal in the Process of Coal Conversion

ABSTRACT The technology of permeable reactive barriers (PRB) is one of the most frequently developed methods for protecting soil and water from pollution. These barriers are zones filled with reactive material in which contaminants are immobilized and/or their concentration is reduced to the limit values during the flow of contaminated groundwater. This article presents a study on the efficiency of the removal of contaminants from the post-processing water from the underground coal gasification (UCG) process. The tests were carried out in a laboratory using a flow-through reactor design. The post-processing water came from a UCG experiment carried out in the Barbara mine, Mikołów, Poland. Activated coal, zeolite, and nano-iron were used as the reactive materials in the experiment. The obtained results were compared to tests carried out with reference water (artificial) with strictly defined characteristics. Research has shown that activated carbon is the most effective material used in the reaction zone for removing organic contaminants from groundwater generated during the coal conversion process. A new feature is the use of PRB in a georeactor zone during the UCG process to limit the potential risk of contamination spreading in the case of uncontrolled and unpredictable operation, in emergency situations related to gas leaks into the environment, during underground fires, and for water polluted by high-toxicity substances.