• Energy Research
• 11. Sustainability close

Abstract Power generation sector is facing important challenges to develop energy efficient solutions at the same time with reducing the greenhouse gas emissions (mainly CO 2 ). Oxy-fuel combustion is a promising power generation technology for reducing both energy and cost penalties for CO 2 capture. This paper presents a detailed techno-economic analysis for oxy-combustion power plant to generate about 350 MW net power with a carbon capture rate higher than 90%. Both fossil fuels (coal and lignite) and renewable energy sources (sawdust) were used to fuel a super-critical power plant (live steam parameters: 582 °C/29 MPa). The assessment is based on numerical analysis, the models of various power plant sub-systems being built in ChemCAD and Thermflow software. As benchmark option used to quantify the CO 2 capture energy and cost penalties, the same super-critical power plant without CCS was considered. The investigated coal, lignite and sawdust oxy-combustion cases show an energy penalty of 9–12 net efficiency percentage points, 37–50% increase of total capital investment, the O&M costs are increasing with 7–15% and the electricity cost with 54–95% (all compared to coal-fuelled non-CCS case). Sensitivity studies were also performed to evaluate the influence of various economic parameters on electricity and CO 2 avoidance costs.

Hydrogen is expected to play a significant role in the future energy systems, given the global increase in energy demand, which is driven by the accelerated growth of the world's population, the on-going industrial development and urbanization as well as the higher standards of living and education. In this paper, the life cycle assessment (LCA) methodology is used to evaluate the environmental impact of two different gasification based hydrogen production technologies: hydrogen production by biomass steam gasification in a dual fluidized bed reactor system (DFB) and hydrogen production by gasification of coal and biomass using entrained flow technology (EF). For both hydrogen production pathways the gasification plant, raw materials production, pre-processing, and transportation are included in the life cycle assessment and also hydrogen delivery to consumers. The DFB cases have lower global warming potential than the EF cases. Also the abiotic depletion fossil potential and the human toxicity potential are lower. The acidification and eutrophication potentials are lower for the EF cases.

a b s t r a c t Carbon capture and storage (CCS) technologies are expected to play a significant role in the coming decades for curbing the greenhouse gas emissions and to ensure a sustainable development of power generation and other energy-intensive industrial sectors. Chemical looping systems are very promising options for intrinsically capture CO2 with lower cost and energy penalties. Gasification offers significant advantages compared with other technologies in term of lower energy and cost penalties for carbon capture, utilization of wide range of fuels, poly-generation capability, plant flexibility, lower environmental impact, etc. The aim of this paper was to propose and evaluate conceptual designs of large scale coal gasification plants with pre- and post-combustion capture based on various chemical looping options. Hydrogen and power co-generation was evaluated as potential way to increase energy efficiency of such plants. The plant concepts generated around 420–600 MW net electricity with at least 90% carbon capture rate. For co-generation scenario, a flexible hydrogen output was evaluated in the range of 0–200 MWth (LHV). The results showed net electrical efficiency ranging from 35 to 41%, most of the cases having an almost total carbon capture rate (>99%). Hydrogen co-production show as promising way for efficiency increase. © 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

AbstractPower generation is one of the industrial sectors with major contribution to greenhouse gas emissions (especially CO2). For climate change mitigation, a special attention is given to the reduction of CO2 emissions by applying capture and storage techniques in which CO2 is captured from energy-intensive processes and then stored in suitable safe geologic locations. Carbon capture and storage (CCS) technologies are expected to play a significant role in the coming decades for curbing the greenhouse gas emissions and to ensure a sustainable development of power generation and other energy-intensive industrial sectors (e.g. cement, metallurgy, petro-chemical etc.). Among various carbon capture options, chemical looping systems are very promising options for intrinsically capture CO2 with lower cost and energy penalties.This paper evaluates calcium looping process as a promising carbon capture option to be applied in the most important coal- based power generation technologies. Combustion technology (Pulverized Fuel - PF) operated in both sub-critical and super- critical steam conditions were evaluated. Also, the gasification technology using an oxygen-blown entrained-flow gasifier was evaluated. As benchmark options, the same power generation technologies were evaluated without CCS. The power plant case studies investigated in the paper produces around 545 – 560 MW net power with at least 90% carbon capture rate. The modeling and simulation of the whole power generation schemes produced the input data for quantitative technical and environmental evaluations of power plants with carbon capture (similar power plant concept without CCS was used as reference for comparison). Mass and energy integration tools were used to assess the integration aspects of calcium looping unit into the whole power plant design, to optimize the overall efficiency and to evaluate the main sources of energy penalty for carbon capture.

This paper investigates the impact of capture of carbon dioxide (CO2) from fossil fuel power plants on the emissions of nitrogen oxides (NOX) and sulphur oxides (SOX), which are acid gas pollutants. This was done by estimating the emissions of these chemical compounds from natural gas combined cycle and pulverized coal plants, equipped with post-combustion carbon capture technology for the removal of CO2 from their flue gases, and comparing them with the emissions of similar plants without CO2 capture. The capture of CO2 is not likely to increase the emissions of acid gas pollutants from individual power plants; on the contrary, some NOX and SOX will also be removed during the capture of CO2. The large-scale implementation of carbon capture is however likely to increase the emission levels of NOX from the power sector due to the reduced efficiency of power plants equipped with capture technologies. Furthermore, SOX emissions from coal plants should be decreased to avoid significant losses of the chemicals that are used to capture CO2. The increase in the quantity of NOX emissions will be however low, estimated at 5% for the natural gas power plant park and 24% for the coal plants, while the emissions of SOX from coal fired plants will be reduced by as much as 99% when at least 80% of the CO2 generated will be captured.

Decarbonization of energy-intensive systems (e.g., heat and power generation, iron, and steel production, petrochemical processes, cement production, etc.) is an important task for the development of a low carbon economy. In this respect, carbon capture technologies will play an important role in the decarbonization of fossil-based industrial processes. The most significant techno-economic and environmental performance indicators of various fossil-based industrial applications decarbonized by two reactive gas-liquid (chemical scrubbing) and gas-solid CO2 capture systems are calculated, compared, and discussed in the present work. As decarbonization technologies, the gas-liquid chemical absorption and more innovative calcium looping systems were employed. The integrated assessment uses various elements, e.g., conceptual design of decarbonized plants, computer-aided tools for process design and integration, evaluation of main plant performance indexes based on industrial and simulation results, etc. The overall decarbonization rate for various assessed applications (e.g., power generation, steel, and cement production, chemicals) was set to 90% in line with the current state of the art in the field. Similar non-carbon capture plants are also assessed to quantify the various penalties imposed by decarbonization (e.g., increasing energy consumption, reducing efficiency, economic impact, etc.). The integrated evaluations exhibit that the integration of decarbonization technologies (especially chemical looping systems) into key energy-intensive industrial processes have significant advantages for cutting the carbon footprint (60–90% specific CO2 emission reduction), improving the energy conversion yields and reducing CO2 capture penalties.