• Energy Research

The environmental impact represents a significant constraint for fossil fuel-intensive industrial processes in transition to a low-carbon scenario. This paper is evaluating the potential energy efficiency improvements in reactive gas–liquid absorption process used for CO2 capture from coal-based super-critical CFBC power plants. Two improved configurations for Methyl diethanolamine (MDEA)-based post-combustion CO2 capture were assessed: absorption intercooling and lean vapour recompression as well as the combination of both. The improved MDEA gas–liquid absorption configurations were compared to conventional MDEA and MEA-based systems for post-combustion CO2 capture as well as the CFBC power plant without carbon capture to assess both the energy and cost penalties for CO2 capture. As the results show, the proposed innovative concepts exhibit better specific thermal energy consumptions for solvent regeneration (2.24–2.58 vs. 2.97 MJ/kg CO2), higher net electrical efficiency (34 vs. 32%) and improved economic indicators (e.g. 2403 vs. 2552 €/kW net power as specific capital investment, 39.2 vs. 41.6 €/MWh as O&M costs, 79 vs. 84 €/MWh as cost of electricity) compared to the conventional MDEA and MEA cases.

Abstract Large scale biomass utilisation in energy-related applications is of paramount importance to reduce the fossil CO 2 emissions. At European level, about a third of energy consumption is expected to be covered by renewables in the next 15 years. In addition, the CO 2 emissions need to be reduced by 40% compared to the 1990 level. Within this context, innovative energy-efficient low carbon technologies have to be developed. Chemical looping is a promising conversion option to deliver reduced energy and cost penalties for CO 2 capture. This paper assesses biomass direct chemical looping (BDCL) concept for hydrogen and power co-production. The concept is illustrated using an ilmenite-based system to produce 400–500 MW net power with flexible hydrogen output (up to 200 MW th ). The performances are assessed through computational methods, with the mass and energy balances being used for in-depth techno-economic analysis. The biomass direct chemical looping delivers both high energy efficiencies (~ 42% net efficiency) with almost total carbon capture rate (> 99%) compared to other CO 2 capture options (e.g. gas–liquid absorption). The economic parameters show also a reduced CO 2 capture cost penalty for biomass direct chemical looping technology compared to gas–liquid absorption (e.g. 7% reduction of specific capital investment).

Cost-effective CO2 capture and storage (CCS) is critical for the rapid global decarbonization effort recommended by climate science. The increase in levelized cost of electricity (LCOE) of plants with CCS is primarily associated to the large energy penalty involved in CO2 capture. This study therefore evaluates three high-efficiency CCS concepts based on integrated gasification combined cycles (IGCC): (1) gas switching combustion (GSC), (2) GSC with added natural gas firing (GSC-AF) to increase the turbine inlet temperature, and (3) oxygen production pre-combustion (OPPC) that replaces the air separation unit (ASU) with more efficient gas switching oxygen production (GSOP) reactors. Relative to a supercritical pulverized coal benchmark, these options returned CO2 avoidance costs of 37.8, 22.4 and 37.5 €/ton (including CO2 transport and storage), respectively. Thus, despite the higher fuel cost and emissions associated with added natural gas firing, the GSC-AF configuration emerged as the most promising solution. This advantage is maintained even at CO2 prices of 100 €/ton, after which hydrogen firing can be used to avoid further CO2 cost escalations. The GSC-AF case also shows lower sensitivity to uncertain economic parameters such as discount rate and capacity factor, outperforms other clean energy benchmarks, offers flexibility benefits for balancing wind and solar power, and can achieve significant further performance gains from the use of more advanced gas turbine technology. Based on all these insights, the GSC-AF configuration is identified as a promising solution for further development.

Abstract There is a growing concern about the impact of energy system decarbonisation on natural resources, such as raw materials and freshwater. Along this line, this paper assesses the needs for cooling water and construction materials of pulverised coal combustion (PF), integrated gasification combined cycle (IGCC) and natural gas combined cycle (NGCC) power generation technologies with and without CCS (Carbon capture and storage). Moreover, the paper evaluates how the integration of CCS technologies influences the economics and operational performance of power plants providing up-dated techno-economic indicators. Introduction of CO2 capture results in an increase of specific water consumption compared to a conventional plant which is more significant in the cases of PF and NGCC (56–62% and 50%) than in IGCC (9–12%). Therefore, the large scale deployment of CCS can have a significant impact on freshwater resources. The introduction of CO2 capture also increases significantly the amount of plant construction materials. The increase is up to 100% for concrete and steel and up to 27% for copper and polyethylene. The cost of construction materials is 8–15% of total investment costs, hence any changes in their prices can have a measurable impact on the cost of a plant and hence on the competitiveness of the underlying technology.

Abstract This paper evaluates biomass and solid wastes co-gasification with coal for energy vectors poly-generation with carbon capture. The evaluated co-gasification cases were evaluated in term of key plant performance indicators for generation of totally or partially decarbonized energy vectors (power, hydrogen, substitute natural gas, liquid fuels by Fischer–Tropsch synthesis). The work streamlines one significant advantage of gasification process, namely the capability to process lower grade fuels on condition of high energy efficiency. Introduction in the evaluated IGCC-based schemes of carbon capture step (based on pre-combustion capture) significantly reduces CO2 emissions, the carbon capture rate being higher than 90% for decarbonized energy vectors (power and hydrogen) and in the range of 47–60% for partially decarbonized energy vectors (SNG, liquid fuels). Various plant concepts were assessed (e.g. 420–425 MW net power with 0–200 MWth flexible hydrogen output, 800 MWth SNG, 700 MWth liquid fuel, all of them with CCS). The paper evaluates fuel blending for optimizing gasification performance. A detailed techno-economic evaluation for hydrogen and power co-generation with CCS was also presented.

Decarbonizing the cement manufacturing sector presents an interesting and pressing challenge as it is one of the largest energy consumers in industry (i.e., 7%), emitting considerable amounts of anthropogenic carbon dioxide (i.e., 7%). This paper performs a technical and environmental assessment of decarbonisation of cement production through process modelling and simulation, thermal integration analysis, and Life Cycle Assessment (LCA). Integration of three post-combustion capture methods for a conventional cement plant with an annual productivity of one million tons and a carbon capture rate of 90% is evaluated in comparison to the reference case without carbon capture and storage (CCS). Mass and energy balances derived from simulations are used for the assessment of three innovative capture systems: reactive gas-liquid absorption using Methyl-Di-Ethanol-Amine, reactive gas-solid adsorption using calcium looping (CaL) technology and membrane separation. For the LCA study, a "cradle-to-gate" approach is carried out using GaBi software, according to the ReCiPe impact assessment method. The general conclusion is that integrating the CCS methods into the cement production process leads to a decrease in global warming potential (GWP) in the range of 69.91%-76.74%. Of the CCS technologies analysed, CaL technically outperforms the others as it requires 34% less coal and provides 1.6 times higher gross energy efficiency. From an environmental perspective, CaL integration ranks first, with the lowest scores in six of the nine impact categories and a GWP reduction of 76.74% compared to the baseline scenario without CCS.

Abstract This paper investigates the technical aspects of innovative hydrogen production concepts based on coal gasification with CO 2 capture. More specifically, it focuses on the technical evaluation and the assessment of performance of a number of plant configurations based on standard entrained-flow gasification processes (dry feed and slurry feed types) producing hydrogen at pipeline pressure, which incorporate improvements for increasing hydrogen purity and pressure. The dry feed type of entrained-flow gasifier is currently considered to be the most efficient means of producing hydrogen from coal. The main shortcomings are relatively low hydrogen purity due to the need of using nitrogen as a transport gas for the coal and a pressure limitation of this type of design. The purity issue can be solved by using captured CO 2 to transport the coal in the gasifier. The pressure limitation can be overcome by using in-plant compression of the raw syngas. Simulations, made using commercial process flow modelling packages (ChemCAD), show that these changes can be made without compromising plant efficiency; on the contrary, the efficiency slightly increases because of the better thermal integration of the plant.