• Energy Research

Hydrogen production from natural gas, combined with advanced CO2 capture technologies, such as iron-based chemical looping (CL), is considered in the present work. The processes are compared to the conventional base case, i.e. hydrogen production via natural gas steam reforming (SR) without CO2 capture. The processes are simulated using commercial software (ChemCAD) and evaluated from a technical point of view considering important key performance indicators such as hydrogen thermal output, net electric power, carbon capture rate and specific CO2 emissions. The environmental evaluation is performed using Life Cycle Analysis (LCA) with the following system boundaries considered: i) hydrogen production from natural gas coupled to CO2 capture technologies based on CL, ii) upstream processes such as: extraction and processing of natural gas, ilmenite and catalyst production and iii) downstream processes such as: H2 and CO2 compression, transport and storage. The LCA assessment was carried out using the GaBi6 software. Different environmental impact categories, following here the CML 2001 impact assessment method, were calculated and used to determine the most suitable technology. Sensitivity analyses of the CO2 compression, transport and storage stages were performed in order to examine their effect on the environmental impact categories. 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12 Energy Procedia, 63 ISSN:1876-6102

Abstract The most promising technology for carbon dioxide capture from coal and natural gas fired power plants at large scale applications is based on post-combustion method using gas–liquid absorption. The paper evaluates carbon dioxide absorption, at low partial pressures, from flue gases by post-combustion capture using aqueous solutions of various alkanolamines: monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), 2-amino-2methyl-1-propanol (AMP) and their corresponding mixtures. At a constant capture rate of about 90%, the performance of these aqueous alkanolamine solutions is compared in terms of solvent loading and overall energy consumption. The objective of the present paper is to assess using a multicriterial analysis (e.g. energy consumption, environmental and operational criteria) the carbon dioxide capture using the above alkanolamines and to investigate the effect of using alkanolamine mixtures as solvent on the gas treatment process. The evaluation was based on Aspen Plus ® simulations. As illustrative example, the case of an IGCC coal-fired power plant generating 375–450 MW e net electricity with and without post-combustion capture was presented in details.

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.

The environmental evaluation of the sorption-enhanced water–gas shift (SEWGS) process to be used for the decarbonization of an integrated steel mill through life cycle assessment (LCA) is the subject of the present paper. This work is carried out within the STEPWISE H2020 project (grant agreement No. 640769). LCA calculations were based on material and energy balances derived from experimental activities, modeling activities, and literature data. Wide system boundaries containing various upstream and downstream processes as well as the main integrated steel mill are drawn for the system under study. The environmental indicators of the SEWGS process are compared to another carbon capture and storage (CCS) technology applied to the iron and steel industry (e.g., gas–liquid absorption using MEA). The reduction of greenhouse gas emissions for SEWGS technology is about 40%. For the other impact indicators, there is an increase in the SEWGS technology (in the range of 7.23% to 72.77%), which is mainly due to the sorbent production and transportation processes. Nevertheless, when compared with the post-combustion capture technology, based on gas–liquid absorption, from an environmental point of view, SEWGS performs significantly better, having impact factor values closer to the no-capture integrated steel mill.

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.

Even though the energy penalties and solvent regeneration costs associated with amine-based absorption/stripping systems are important challenges, this technology remains highly recommended for post-combustion decarbonization systems given its proven capture efficacy and technical maturity. This study introduces a novel centralized and decentralized hybrid control strategy for the post-combustion carbon capture plant, aimed at mitigating main disturbances and sustaining high system performance. The strategy is rooted in a comprehensive mathematical model encompassing absorption and desorption columns, heat exchangers and a buffer tank, ensuring smooth operation and energy efficiency. The buffer tank is equipped with three control loops to finely regulate absorber inlet solvent solution parameters, preventing disturbance recirculation from the desorber. Additionally, a model-based controller, utilizing the model predictive control (MPC) algorithm, maintains a carbon capture yield of 90% and stabilizes the reboiler liquid temperature at 394.5 K by manipulating the influent flue gas to the lean solvent flowrates ratio and the heat duty of the reboiler. The hybrid MPC approach reveals efficiency in simultaneously managing targeted variables and handling complex input–output interactions. It consistently maintains the controlled variables at desired setpoints despite CO2 flue gas flow disturbances, achieving reduced settling time and low overshoot results. The hybrid control strategy, benefitting from the constraint handling ability of MPC, succeeds in keeping the carbon capture yield above the preset minimum value of 86% at all times, while the energy performance index remains below the favorable value of 3.1 MJ/kgCO2.