Syngas Energy Research Articles

Use of lower grade coals in IGCC plants with carbon capture for the co-production of hydrogen and electricity

This paper investigates the potential use of lower grade coals in an IGCC-CCS plant that generates electricity and produces hydrogen simultaneously with carbon dioxide capture and storage. The paper underlines one of the main advantages of gasification technology, namely the possibility to process lower grade coals, which are more widely available than the high-grade coals normally used in European power plants. Based on a proposed plant concept that generates about 400 MW net electricity with a flexible output of 0–50 MW th hydrogen and a carbon capture rate of at least 90%, the paper develops fuel selection criteria for coal fluxing and blending of various types of coal for optimizing plant performance e.g. oxygen consumption, hydrogen production potential, specific syngas energy production per tonne of oxygen consumed, etc. These performance indicators were calculated for a number of case studies through process flow simulations. The main conclusion is that blending of coal types of higher and lower grade is more beneficial in terms of operation and cost performance than fluxing high-grade coals.

Multifunctional Energy System (MES) With Multifossil Fuels and Multiproducts

A new kind of multifunctional energy system (MES) with multifossil fuels and multiproducts is proposed in this paper. This new system consumes coal and natural gas as fuel simultaneously, and cogenerates methanol and power. Coal and natural gas are utilized synthetically based on the method of dual-fuel reforming, which integrates the methane/steam reforming and the combustion of coal. During the dual-fuel reforming process, combustion of coal provides high-temperature thermal energy to methane/steam reforming reaction to product syngas. Then, the chemical energy of syngas is used efficiently since the new system integrates the chemical process and power plant. In this manner, the energy including both chemical energy of fuels and thermal energy can be used more effectively from the viewpoint of the whole system. As a result, the total energy efficiency of this new system was about 60–66%. Compared with the conventional systems, the new system provides an energy savings of about 8–15%. The results obtained here indicate that this new system may provide a new way to utilize coal and natural gas more efficiently and economically.

Comparison of thermodynamic and environmental indexes of natural gas, syngas and hydrogen production processes

The thermodynamic efficiency and the environmental sustainability of selected processes that deliver gaseous energy carriers (natural gas, syngas from coal gasification, and hydrogen from steam reforming of natural gas and alkaline electrolysis) is explored by means of a multi-criteria, multi-scale approach based on four methods: material flow accounting, energy analysis, exergy analysis, and emergy synthesis. The average energy and exergy conversion efficiencies of syngas (76% and 75%, respectively) are found to be higher than those for hydrogen (64% and 55%). However, coal-to-syngas conversion generates a significant amount of solid waste, which should be dealt with carefully. In addition, the material intensity is much higher for syngas (e.g. abiotic MI=768 g/g) than for natural gas and hydrogen (21 and 39 g/g, respectively), indicating a higher load on the environment. On the other hand, the emergy intensity (transformity) for syngas (5.25×10 4 seJ/J) is shown to be lower than for hydrogen (9.66×10 4 seJ/J), indicating a lower demand for global environmental support. Therefore, material intensities and transformities offer two complementary pieces of information: transformities account for the “memory” of the environmental resources that were used up in the past for the production of the inputs, whereas MIs are strictly calculated within the time frame of the life cycle of the investigated process. The higher transformity values calculated for pure hydrogen suggest careful and appropriate use of such an energy vector.