Post-combustion Capture Technology Research Articles

Comparative multi-aspect study of two scenarios and optimization of the biomass-based cogeneration system integrated with the carbon capture and utilization technology

Combined Heat and Power (CHP) system based on bio-energy is an energy-saving and environment friendly way to utilize energy, but in the background of the "carbon peaking and carbon neutrality" strategy, ensuring low-carbon operation of CHP systems becomes imperative. In this paper, we introduce two distinct CHP system scenarios based on post-combustion carbon capture technologies: a syngas-based gas turbine cycle CHP system (scenario 1) and a biogas-based steam turbine cycle CHP system (scenario 2). Then, a techno-economic evaluation has been conducted to investigate their performance under varying operational conditions of heating and power load, as well as carbon capture technology. The findings reveal that, given the same biomass input rate, the syngas-based CHP system yields superior energy and economic outcomes. To simultaneously mitigate CO2 emissions and reduce electricity costs, a process of multi-objective optimization is employed. This optimization endeavor also focuses on maximizing the overall exergy efficiency. Consequently, scenario 1 experiences substantial improvements in performance metrics. Notably, the overall energy and exergy efficiencies reach 17.32 % and 14.58 % respectively. Additionally, the power and heating load are estimated at 2.58 and 2.17 MW correspondingly. The levelized cost of electricity and heating are assessed at 30.55 USD/MWh and 36.05 USD/GJ, respectively, coinciding with a reduction in CO2 emissions to 98.27 kgCO2/MWh.

MODELING AND SIMULATION OF POST-COMBUSTION CO 2 CAPTURE PROCESS FOR 6.4 MWE BAGASSE FUELED POWER PLANT

The emission of carbon dioxide, a greenhouse gas, contributes to the phenomenon of climate change; the largest source of carbon dioxide emissions are fossil fuel power plants. Post-combustion carbon capture (PCC) technology, which is based on solvents, is currently the most advanced technology for reducing carbon dioxide emissions from power plants. The Post-combustion Process, which uses conventional solvents, has a number of disadvantages, including high energy consumption for regeneration, solvent losses, corrosion of equipment, thermal instability, and environmental impact. Ionic liquids (ILs) and IL-based solvents have produced a novel method of CO 2 capture that is highly efficient, economical, and environmentally friendly. A rate-based steady-state model of the PCC process using the ionic liquid 1-hexyl-3-methylimidazolium glycine ([Hmim] [Gly]) was investigated using Aspen Plus ®. In Aspen Plus ® Electrolyte NRTL method and RK equation of state are used to compute liquid and vapor properties. From the process analysis carried out, it was found that the height and diameter of the absorber packing, the liquid-to-gas ratio and the solvent and flue gas temperatures have a positive effect on the CO 2 capture efficiency. The result showed a maximum CO 2 capture efficiency of 92% at a packed height of 12m and diameter of 0.9m. The best capture efficiency of 98.82% was achieved at an L/G ratio of 4.0.the process simulation study examined five key parameters for ([Hmim] [Gly]) solvent which may reduce the energy and cost required for CO 2 capture. The results show that aqueous ([Hmim] [Gly]) is a promising absorbent for CO 2 capture. Offering a pathway towards more sustainable and efficient carbon capture technologies. This study contributes to the advancement of carbon capture technologies and underscores their significance in mitigating climate change impacts.

Techno-Economic, Environmental, and Policy Perspectives of Carbon Capture to Fuel Technologies

This research paper provides a comprehensive exploration of carbon capture to fuel technologies, covering various capture methodologies and conversion processes. The analysis begins by dissecting post-combustion, pre-combustion, and direct air capture technologies, elucidating their principles, advantages, and limitations. A focus on the conversion of captured carbon into usable fuels delves into synthetic fuels and hydrogen production methods, detailing chemical processes, catalysts, and energy requirements. Moving beyond technical aspects, the paper critically analyzes the efficiency and viability of carbon capture to fuel processes, employing case studies and real-world examples to illustrate the practical application of techno-economic assessments and life cycle analyses. Economic considerations further assess implementation costs, operational expenses, and potential revenue streams, drawing insights from existing economic models and case studies. Environmental impact and benefits take center stage, evaluating potential reductions in greenhouse gas emissions, resource efficiency, and ecological considerations associated with converting captured carbon to fuel. A comparative analysis with other carbon capture applications offers a holistic perspective on the environmental footprint. The regulatory landscape is thoroughly examined, encompassing existing policies, government incentives, and international agreements influencing the development and deployment of carbon capture to fuel technologies. The research concludes with reflections on the current status, challenges, and a roadmap for future advancements, serving as a comprehensive guide for researchers, policymakers, and industry stakeholders in the pursuit of sustainable energy solutions.

Emissions reduction in LNG production facilities through emerging post-combustion carbon capture and storage technologies

The liquefied natural gas (LNG) sector relies extensively on gas turbines for on-site power generation and to drive refrigeration compressors. They provide an efficient and reliable energy source for LNG operations in remote locations. With upcoming changes to the Safeguard Mechanism in Australia, there is an increased focus on Scope 1 emissions, so management and targeted reduction are a priority to reduce liabilities. Despite technology advancements, gas turbines remain one of the largest sources of carbon dioxide (CO2) emissions in LNG production facilities. Also, in Australia, many facilities are not grid-connected, meaning that displacement of Scope 1 emissions through renewable electricity sourcing is a challenge. To develop deeper cuts in Scope 1 emissions, one solution is to deploy post-combustion carbon capture and storage (CCS) on existing gas turbines, with the potential to reduce associated emissions by over 90%. Globally, a number of LNG facilities are already deploying CCS to permanently store reservoir CO2 from the LNG processing trains. Several Australian LNG facilities are located in close proximity to potential CO2 storage reservoirs, meaning that a coordinated approach to both reservoir and post-combustion CO2 should be considered when sizing pipelines, shipping systems and storage wells to optimise and leverage the required investment. This paper outlines the technological, economic and policy aspects of integrating both reservoir post-combustion CCS on LNG facilities, including barriers and opportunities for deployment. It will discuss new developments and enablers for CCS to be more widely deployed at LNG production sites.

Solar-Assisted Carbon Capture Process Integrated with a Natural Gas Combined Cycle (NGCC) Power Plant—A Simulation-Based Study

In the realm of Natural Gas Combined Cycle (NGCC) power plants, it is crucial to prioritize the mitigation of CO2 emissions to ensure environmental sustainability. The integration of post-combustion carbon capture technologies plays a pivotal role in mitigating greenhouse gas emissions enhancing the NGCC’s environmental profile by minimizing its carbon footprint. This research paper presents a comprehensive investigation into the integration of solar thermal energy into the Besmaya Natural Gas Combined Cycle (NGCC) power plant, located in Baghdad, Iraq. Leveraging advanced process simulation and modeling techniques employing Aspen Plus software, the study aims to evaluate the performance and feasibility of augmenting the existing NGCC facility with solar assistance for post-carbon capture. The primary objective of this research is to conduct a thorough simulation of the Besmaya NGCC power plant under its current operational conditions, thereby establishing a baseline for subsequent analyses. Subsequently, a solar-assisted post-combustion capture (PCC) plant is simulated and seamlessly integrated into the existing power infrastructure. To accurately estimate solar thermal power potential at the Baghdad coordinates, the System Advisor Model (SAM) is employed. The integration of solar thermal energy into the NGCC power plant is meticulously examined, and the resulting hybrid system’s technical viability and performance metrics are rigorously evaluated. The paper contributes to the field by providing valuable insights into the technical feasibility and potential benefits of incorporating solar thermal energy into conventional natural gas power generation infrastructure, particularly in the context of the Besmaya NGCC plant in Baghdad. The power generation capacity of the plant was set at 750 MW. With this capacity, the annual CO2 generation was estimated at 2,119,318 tonnes/year which was reduced to 18,064 tonnes/year (a 99% reduction). The findings aim to inform future decisions in the pursuit of sustainable and efficient energy solutions, addressing both environmental concerns and energy security in the region.

Two-dimensional interfacial enhanced CO2 adsorption performance of porous organic amine solids: Structure-activity relationships and DFT calculations

The utilization of inexpensive and efficient amine-functionalized adsorbents has become a research hotspot in post-combustion capture technology. Meanwhile, the structure of the support and the selection of organic amines are the primary considerations affecting the CO2 adsorption performance. Herein, the novel solid amine adsorbent materials with amine-support interfacial effect were successfully synthesized in this study by loading four organic amines (TETA, TEPA, PEHA, and PEI) onto expanded vermiculite (EVMT) support with the layered structure. The results indicated that EVMT-50TETA exhibited superior CO2 adsorption capacity (132.5 mg/g) along with effective regeneration capability. This was attributed to the unique layered structure of EVMT that facilitates the dispersion of TETA on its surface or between layers as well as the formation of hydrogen bonds between surface functional groups (–OH) and amines to enhance the amine-support interfacial interaction. Furthermore, the minimal volume expansion of TETA during CO2 adsorption enables improved diffusion of CO2 in channels and enhanced accessibility to active sites. DFT calculations show higher binding energies and faster CO2 adsorption-diffusion rates between TETA and EVMT support. In situ DRIFTS experiments revealed that the process of CO2 adsorption followed the zwitterion mechanism, in which the zwitterion can be reversibly deprotonated to form ammonium carbamate and carbamic acid. This study provides comprehensive insights into the supports and amines interfacial effects through systematic investigation, offering both simplified synthesis strategies and profound theoretical support for studying solid amine adsorbents.

Assessing economic trade-off for advances in amine-based post-combustion capture technology

The study aims to evaluate the trade-off relationship between reducing energy consumption through technological improvements, including process modifications and the use of CO2-absorbing solvents, and the increased costs associated with their implementation in power and industrial sectors. Additionally, the economic potentials of heat-integrated CO2 capture and amine solvent degradation are explored. Four representative cases are considered, involving changes to lean vapor compression (LVC) and a blended amine solvent from a monoethanolamine (MEA) benchmark process. The findings indicate that the characteristics of combustion processes have a minor impact on the energy intensity of amine-based CO2 capture, but they significantly affect its cost. This is primarily due to substantial variations in fuel costs and equipment size. Technological advancements, such as process modifications and the use of amine solvents with high CO2 absorption capacity, play a crucial role in reducing both the energy consumption and costs associated with CO2 capture. However, the study suggests that careful consideration is needed when utilizing expensive amine solvents with high CO2 absorption capacity, particularly in situations prone to solvent degradation, as solvent loss can significantly impact the economic viability of CO2 capture.

Solvent-mediated modification of thermodynamics and kinetics of monoethanolamine regeneration reaction in amine-stripping carbon capture: Computational chemistry study.

A major limitation of amine-based post-combustion carbon capture technology is the necessity to regenerate amines at high temperatures, which dramatically increases operating costs. This paper concludes the effect of solvent choice as a possible route to modify the thermodynamics and kinetics characterizing the involved amine regeneration reactions and discusses whether these modifications can be economically beneficial. We report experimentally benchmarked computational chemistry calculations of monoethanolamine regeneration reactions employing aqueous and non-aqueous solvents with a wide range of dielectric constants. Unlike previous studies, our improved computational chemistry framework could accurately reproduce the right experimental activation energy of zwitterion formation. From the thermodynamics and kinetics of the predicted reactions, the use of non-aqueous solvents with small dielectric constants led to reductions in regeneration Gibbs free energies, activation barriers, and enthalpy changes. This can reduce energy consumption and give an opportunity to run desorption columns at relatively lower temperatures, thus offering the possibility of relying on low-grade waste heat as an energy input.

Recent advances and challenges in ionic materials for post-combustion carbon capture

The massive combustion of fossil fuels has resulted in excessive emissions of carbon dioxide (CO2), which has become an urgent environmental problem worldwide. Post-combustion capture technology is one of the most promising carbon capture technologies with rapid growth potential. Ionic materials hold great promise as superior adsorbents for post-combustion capture, offering advantages such as increased adsorption capacity, adjustable adsorption rate, and enhanced operational stability. This review mainly summarized the rational design of pure ionic materials and ion hybrid materials for carbon capture. The relationship between the structural design of materials and the control of capacity, rate, and stability of carbon capture was focused on. A complete description of several emerging ionic materials and their potential for carbon capture is also given. Simultaneously, novel control concepts and rapid screening techniques are introduced. Finally, the article discusses the problems and solutions for the use of ionic materials in future post-combustion capture technology. This work deepens our comprehension of the construction and control of ionic materials, offering valuable insights for the advancement of industrial carbon capture.

Technoeconomic evaluation of post-combustion carbon capture technologies on-board a medium range tanker

The international maritime organization has recently set targets and timelines for reducing global greenhouse gas emissions from the maritime industry, which currently stand at 1.1 Gt/year and make 3 % of the global emissions. Reducing emissions by increasing engine efficacy is the immediate target, but there is a limit to how much this path can achieve. Onboard post-combustion carbon capture and concentration in large marine vessels is emerging as an interim approach to reduce maritime emissions until large-scale deployment of low/zero emission fuels become viable. In this paper, we evaluate three carbon capture technologies (chemical absorption using either aqueous MEA or aqueous NH3 as the solvent, cryogenic separation, and membrane separation) for a medium-range tanker for two fuels, namely heavy fuel oil and liquefied natural gas. The capture cost per tonne of CO2 (recovery>90 %, purity>95 %) was considered as the assessment criterion, with simultaneous evaluation of other aspects such as energy and space demands. The simulations were carried out using MATLAB and ASPEN V12. For rate-based models, the adjustable parameters for the model were tuned using pilot plant data. Additionally, options for hot and cold energy integration were also assessed and implemented. Based on the reference ship conditions and assessment criteria, the simulation studies show that amine-based absorption is the best prospect for on-board capture by a clear margin.

Progress in Post-Combustion Technology for Carbon Dioxide Capture

In the face of climate change and global warming caused by the increase in atmospheric carbon dioxide released by the combustion of fossil fuels, carbon capture technologies become pivotal for mitigating greenhouse gas emissions, particularly carbon dioxide. Among these carbon capture technologies, post-combustion capture has gained widespread application. In this article, the absorption and adsorption methods in post-combustion carbon capture technology, including the mechanism of the chemical and physical aspects of both methods as well as the absorbents and adsorbent materials used in them, will be specifically introduced. Moreover, the current and potential applications in the field of emissions reduction are also elaborated. These post-combustion carbon capture methods are expected to reduce environmental harm while maintaining energy efficiency, providing an effective solution to the problem of global warming.

Heat and mass transfer of a novel CO2 desorption process integrated with highly turbulent catalytic heat exchanger

This was the first work that pioneered the development a novel catalytic CO2 desorption process using an agitated jacket vessel with a coil heat exchanger (JVC) into a bench-scale pilot plant for post-combustion carbon capture technology. The key parameters of heat and mass transport e.g., overall heat transfer coefficient, overall volumetric liquid-side mass transfer coefficient and the enhancement factor for catalyst effect, were experimentally investigated by varying the operating conditions, including temperature, stirring speed, and heating methods. The proposed investigations revealed that the utilization of the JVC was a promising technology for improving heat transfer and mass transfer performance in the desorption process due to the high turbulence flow and more favorable thermal distributions achieved by the JVC. In comparison to the conventional process with a fixed catalyst bed, the JVC demonstrated a remarkable approximately 30 % catalytic enhancement and a substantial 50 % reduction in catalyst demand. Additionally, other potential benefits and challenges of further practical operations were discussed in this paper. This research carried significant potential to contribute to the advancement of knowledge and offer valuable insights into the practicability of the catalytic desorption process for further commercial application in carbon capture. The integration of catalyst and JVC could potentially motivate the utilization of catalyst towards commercial-scale applications.

Insights into amine-resin matching strategy for CO2 capture: Adsorption performance tests and Mechanistic investigation

The solid amine adsorbents are potential candidates as materials for post-combustion capture technologies. The type of organic amine and porous material are the key factors influencing the amine-based solid adsorbent performance. Furthermore, there has been relatively little research on the matching mechanism between organic amines and porous materials. This study aims to investigate the effect of the degree of matching between different organic amines and porous materials (X-5 resin) on the performance of CO2 capture. The results indicated that 30 wt% TETA was the highest matching degree with X-5 and had the maximum CO2 adsorption of 205.48 mg/g at 30 ℃. The matching degree between the four amines and the X-5 resin followed TETA > TEPA > PEHA > PEI. Since TETA has the simplest molecular structure, it can be conveniently dispersed in the X-5 pores, which not only significantly improves the utilization of active sites but also prevents the phenomena of agglomeration or sintering. Meanwhile, X-5-30TETA has the highest adsorption energy Eads (−85.22 kJ/mol) and the smallest spatial potential resistance, decreasing the mass transfer resistance effectively, thus further increasing the adsorption capacity. Furthermore, the adsorption kinetics results showed that the Avrami model can relatively accurately predict the experimental results of X-5-TPHI CO2 adsorption. Finally, the in situ DRIFTS indicated that the CO2 adsorption reaction over X-5-30TETA followed predominantly an amphipathic centipede mechanism. This work provides a new idea for the investigation of the matching mechanism between organic amines and porous materials.

Carbon Capture Membranes Based on Amorphous Polyether Nanofilms Enabled by Thickness Confinement and Interfacial Engineering.

Thin-film composite membranes are a leading technology for post-combustion carbon capture, and the key challenge is to fabricate defect-free selective nanofilms as thin as possible (100 nm or below) with superior CO2/N2 separation performance. Herein, we developed high-performance membranes based on an unusual choice of semi-crystalline blends of amorphous poly(ethylene oxide) (aPEO) and 18-crown-6 (C6) using two nanoengineering strategies. First, the crystallinity of the nanofilms decreases with decreasing thickness and completely disappears at 500 nm or below because of the thickness confinement. Second, polydimethylsiloxane is chosen as the gutter layer between the porous support and selective layer, and its surface is modified with bio-adhesive polydopamine (<10 nm) with an affinity toward aPEO, enabling the formation of the thin, defect-free, amorphous aPEO/C6 layer. For example, a 110 nm film containing 40 mass % C6 in aPEO exhibits CO2 permeability of 900 Barrer (much higher than a thick film with 420 Barrer), rendering a membrane with a CO2 permeance of 2200 GPU and CO2/N2 selectivity of 27 at 35 °C, surpassing Robeson's upper bound. This work shows that engineering at the nanoscale plays an important role in designing high-performance membranes for practical separations.

Analysis of CO2 capture process from flue-gases in combined cycle gas turbine power plant using post-combustion capture technology

Combined cycle gas turbine power plants (CCGTs) are a combined cycle consisting of a gas turbine and a steam turbine to generate electricity. Sometimes CCGTs incorporate cogeneration to produce both heat and power. After the gas fuel combustion in the gas turbine combustion chamber, the flue gases are passed through the Heat Recovery Steam Generator (HRSG) to extract heat and generate additional electrical power using the steam turbine. The CCGT technology is recognized for its highest efficiency of 58% in electricity production among the power production technology. A highly efficient CCGT power plant with 60% efficiency produces even 2.5 times less CO2 than a modern coal power plant with an efficiency of 45% because of the use of gas fuel and electrical efficiency. The CO2 emission can be reduced further when the post-combustion CO2 capture methods are applied. To perform CO2 capture and to reduce the CO2 emission from power plants, the CO2 mass fraction in flue gas is the crucial parameter for the operation of the Post-combustion Carbon Capture and Storage (PCCS) technology. The PCCS technology uses solvents, which is the aqueous solution of amine that reacts with flue gas and absorbs the CO2, which is treated and separated later. The paper presents the results of the energy analysis of a post-combustion carbon capture process when integrated with a combined cycle gas power plant. The study considered two different gas fuels such as methane and syngas. Syngas composition was determined from the sewage sludge gasification process and can be treated as zero-emission CO2 gas fuel. When the flue gas produced from the syngas is used in PCCS at more than 50% of load conditions, the negative CO2 emission level in large-scale CCGT power plants can be reached. The paper presents the results of mass and energy balance analysis of HRSG of a CCGT integrated with PCCS to perform CO2 capture. The analysis of HRSG using flue gases from methane and syngas is performed by calculating the enthalpy of flue gas, rate of heat exchange, and temperature distribution of each component of HRSG. The comparison of the result shows slight differences due to the different composition and flow rates of flue gases. The flue gas at the outlet of two HRSG is used in the PCCS at different load conditions. An aqueous solution of 30 wt% Monoethanolamine (MEA) with rich loading of 0.5 mol-CO2/mol-MEA and a mixture of 16 wt% 2-amino-2-methyl-1-propanol (AMP) – 14 wt% Piperazine (PZ) with rich loading of 0.62 and 0.86 mol-CO2/mol-amine respectively are used in the PCCS. Due to the reboiler duty of amines, the steam consumed by the PCCS for AMP-PZ regeneration is less compared to MEA. Depending upon the flue gas and solvent used in the PCCS, the power consumed by the PCCS from CCGT power plant is measured from 9.6% to 11.6%. For the given operating condition of the CCGT and PCCS at more than 50% load condition, the negative CO2 emission level can be achieved.

Process simulation and techno-economic analysis on novel CO2 capture technologies for fluid catalytic cracking units

To reduce CO2 emissions in the FCC process, the post-combustion carbon capture and storage (CCS) technology has been first applied in the FCC process due to its ease of retrofit. However, the required chemicals and high energy consumption turn it into a high-cost method. Oxy-fuel combustion, with the use of different advanced air separation units (ASU), has the potential to be a cost-effective technology for carbon capture in the FCC system. This study first develops steady state models of a 1.4 Mt./a resid FCC unit operated in two carbon capture conditions, namely post-combustion and oxy-fuel combustion, by using Aspen Plus. Second, it compares the economic performances of three different ASUs in oxy-fuel combustion, which are cryogenic ASU, pressure swing adsorption (PSA) ASU, and vacuum pressure swing adsorption (VPSA) ASU. A comparative study on the performances of the industrial-scale CCS FCCUs is conducted for a comprehensive analysis. The analysis shows that the power consumption of the whole system reduces by 30–50 MW when adopting the oxy-firing method, as compared to the post-combustion technology. The air-firing FCC unit with a VPSA air separation unit has the highest NPV and IRR (511.76 M$ and 23.45%) among these technologies. It presents the best performance in all aspects including CO2 recovery rate, energy consumption, and economics, which promises to become strongly competitive in CCS technologies of FCCUs.

Comparative techno-economic analysis of the integration of MEA-based scrubbing and silica PEI adsorbent-based CO2 capture processes into cement plants

The objective of this work was to perform the techno-economic analysis for the integration of two post-combustion carbon capture technologies into cement plants, namely monoethanolamine (MEA) scrubbing-based and silica-alkoxylated polyethyleneimine (SPEI) adsorbent-based processes. The key performance indicators were investigated, including emission abatement, energy performance, break-even selling price, CO2 capture and avoidance cost. The technical evaluation showed that the conventional MEA and SPEI-based processes required 3.53 GJ/tonne CO2 and 2.36 GJ/tonne CO2 of regeneration energy when achieving 90% of CO2 capture rate, respectively. In addition, the specific primary energy consumption for CO2 avoided was estimated at 6.5 GJ/tonne CO2 for the MEA-based and 4.3 GJ/tonne CO2 for the SPEI-based process. The CO2 capture costs of MEA and SPEI-based processes were estimated at 61.4 and 49.8 €/tonne CO2, respectively. Meanwhile, the CO2 avoidance cost of MEA and SPEI processes were estimated at 84.7 and 62.2 €/tonne CO2 respectively. The economic evaluation indicated that the cost of clinker production was increased by 108% with the integration of the solvent-based MEA-based and 84% for the SPEI-based processes. However, in the case, the maximum heat of 53.9 MWth is recovered from the reference cement plant, the costs of CO2 capture and CO2 avoidance for both the MEA and SPEI-based processes would be reduced. The CO2 capture costs of MEA and SPEI-based processes would decrease to 48.0 and 35.6 €/tonne CO2, respectively. Additionally, the CO2 avoidance costs for the MEA and SPEI-based processes would be reduced to 57.5 and 44.5 €/tonne CO2, respectively.

Use of artificial intelligence in reducing energy costs of a post-combustion carbon capture plant

Absorption-based carbon capture (ACC) is the most mature technology for abating CO2 among different post-combustion carbon capture technologies. ACC is, however, energy-intensive and requires large heating and cooling utility consumption, resulting in high operational costs. Reliable and fast estimation of these utility consumptions would be valuable for technical and financial feasibility assessment of different ACC process designs. The objective of this study is to develop an artificial intelligence (AI) based approach that predicts these utility consumptions of different ACC process designs. For prediction of specific reboiler duty, which is the most important energy consumption of the plant and the main source of operational costs in the ACC process, the error of the AI models is between 0.4% and 3.6% for different scenarios of utilizing either limited or extensive training data. Moreover, the contribution of each process parameter to energy consumption was identified using explainable artificial intelligence. The findings of this study facilitate the energy-efficient design of ACC plants and provide a prioritized list of parameters to adjust for reducing the energy consumption of an ACC process.

Process simulation and energy analysis of synthetic natural gas production from water electrolysis and CO2 capture in a waste incinerator

Power-to-gas (PtG) and carbon capture and utilisation are expected to play a key role in promoting a sustainable energy transition. In this work, a detailed energy analysis of a complete PtG system integrated with a real waste incinerator is performed. A fraction of the renewable electricity and heat produced by the waste incinerator is used in the PtG system to produce hydrogen, which is further converted into SNG by methanation with CO2 recovered from the plant flue gases. A PtG plant able to produce up to 500 m3/h of SNG is considered. A total of six different plant configurations are analysed, obtained by the combination of different electrolysis and post-combustion carbon capture technologies. Specifically, alkaline and PEM electrolysers are considered for the production of hydrogen, while absorption with monoethanolamine solution, absorption with monoethanolamine and ionic liquid solution, and temperature swing adsorption with solid sorbent are selected for carbon capture. The main sections of the PtG system are modelled and the performance of the overall system is evaluated by computing key performance indicators, such as the global energy efficiency and the Specific Plant Energy Consumption for CO2 Avoided (SPECCA). Special attention is also paid to the thermal integration between the methanation unit and the carbon capture unit. The heat produced during the methanation process is sufficient to cover the entire heat demand of the CO2 capture unit in almost all configurations investigated. In particular, thermal integration increases the global energy efficiency by 5–9% and reduces the SPECCA indicator by 5–8%. Considering the thermally integrated configurations, the global energy efficiency is estimated to be between 44.6% and 46.7%, while the SPECCA value ranges from 40.5 MJ/kg to 42.4 MJ/kg. Finally, some technical considerations are given, including the quality of SNG produced and the degradation phenomena in the considered technologies.

On the cost of zero carbon hydrogen: A techno-economic analysis of steam methane reforming with carbon capture and storage

This article challenges the view that zero carbon hydrogen from steam methane reforming (SMR) is prohibitively expensive and that the cost of CO2 capture increases exponentially as residual emissions approach zero; a flawed narrative often eliminating SMR produced hydrogen as a route to net zero. We show that the capture and geological storage of 100% of the fossil CO2 produced in a SMR is achievable with commercially available post-combustion capture technology and an open art solvent. The Levelised Cost of Hydrogen (LCOH) of 69£/MWhth HHV (2.7£/kg) for UK production remains competitive to other forms of low carbon hydrogen, but retains a hydrogen lifecycle carbon intensity of 5 gCO2e/MJ (LHV) due to natural gas supply chain and embodied greenhouse gas (GHG) emissions. Compensating for the remaining lifecycle GHG emissions via Direct Air Capture with geological CO2 Storage (DACCS) increases the LCOH to 71–86 £/MWhth HHV (+3–25%) for a cost estimate of 100–1000 £/tCO2 for DACCS and the 2022 UK natural gas supply chain methane emission rates. Finally, we put in perspective the cost of CO2 avoidance of fuel switching from natural gas to hydrogen with long term price estimates for natural gas use and DACCS, and hydrogen produced from electrolysis.