To achieve net-zero iron and steel production by 2050, many iron and steel producers are turning to direct reduced iron (DRI)—electric arc furnace (EAF) steel production as an opportunity to achieve significant CO2 emissions reductions relative to current levels. However, additional innovations are required to close the gap between DRI and net-zero steel. Pressurized chemical looping-DRI (PCL-DRI) is a novel technology explored to meet this target, in which the reformer firebox and fired process gas heaters are replaced with PCL combustion units. Captured CO2 is conditioned and compressed for pipeline transportation and storage/utilization. The performance of two different PCL-DRI configurations relative to traditional DRI processes was explored via process simulation: a Midrex-type process and an Energiron-type process. The PCL-DRI processes were shown to have equivalent or lesser total fuel consumption (8% reduction) compared to the base cases, and greater process water production (1... [more]

Carbon dioxide (CO2) has reached a higher level of emissions in the last decades, and as it is widely known, CO2 is responsible for numerous environmental problems, such as climate change. Thus, there is a great need for the application of CO2 capture and storage, as well as of CO2 utilization technologies (CCUS). This review article focuses on summarizing the current CCUS state-of-the-art methods used in Europe. Special emphasis has been given to mineralization methods/technologies, especially in basalts and sandstones, which are considered to be suitable for CO2 mineralization. Furthermore, a questionnaire survey was also carried out in order to investigate how informed about CO2 issues European citizens are, as well as whether their background is relative to their positive or negative opinion about the establishment of CCUS technologies in their countries. In addition, social acceptance by the community requires contact with citizens and stakeholders, as well as ensuring mutual trus... [more]

Global warming, along with increasing global energy demands, has led to the need for a sustainable and low-carbon-based energy economy. In addition to renewable energy technologies, such as biomass, solar, hydro, and wind, another possible strategy to mitigate climate change is the capture/conversion and recycling of CO2. In recent years, many methods for both CO2 capture (mainly adsorption, absorption, and membrane) and conversion (many electrolysis, catalyst, and plasma) have been investigated. Conversion technology is less studied but seems to be very promising. Within that, non-thermal plasma technology has received much interest because it works at low temperatures and atmospheric pressure, and there is no need for high temperature and high electricity consumption, which are typical of the catalyst and electrolysis conversion processes, respectively. Therefore, in order to optimize this emerging technology, simulative kinetic models have been developed with the aim of maximizing b... [more]

Future carbon dioxide capture and storage (CCS) will be impacted by the new scenario in which the energy supply rapidly shifts from oil-based to natural gas-based means, but this shift also presents an opportunity to utilize natural gas hydrates (NGHs). This review discusses the present state of CCS research and development, the advantages of the various approaches, and the barriers to commercialization that exist today. It also provides an evaluation of certain practical small- and large-scale CCS applications. The high initial investment, as well as ongoing maintenance costs, plague today’s commercially accessible CO2 capture technologies, including absorption, adsorption, membranes, and cryogenic separation. Gas hydrate-based capture has the potential to become the dominant method for CO2 separation because of the high recovery rates and purity it provides. Hydrate-based technologies, including CO2 capture, CO2 separation, and transportation, can also be used to reduce greenhouse ga... [more]

Global warming is one of the major problems in the developing world, and one of the major causes of global warming is the generation of carbon dioxide (CO2) because of the burning of fossil fuels. Burning fossil fuels to meet the energy demand of households and industries is unavoidable. The current commercial and experimental techniques used for capturing and storing CO2 have serious operational and environmental constraints. The amine-based absorption technique for CO2 capture has a low absorption and desorption ratio, and the volatile and corrosive nature of the solvent further complicates the situation. To overcome all of these problems, researchers have used ionic liquids (ILs) and deep eutectic solvents (DESs) as a replacement for commercial amine-based solvents. ILs and deep eutectic solvents are tunable solvents that have a very low vapor pressure, thus making them an ideal medium for CO2 capture. Moreover, most ionic liquids and deep eutectic solvents have low toxicity and can... [more]

In the context of the need to significantly reduce greenhouse gas emissions from personal transportation, a new process for the production of e-methanol is presented. It is a CO2 hydrogenation process, powered mainly by renewable energy sources such as photovoltaic electricity, with direct capture of carbon dioxide from the ambient air. With the main objective of estimating the feasibility and the impact of such a large-scale plant, the various components are evaluated in terms of masses and quantities necessary for an annual fuel production of 500,000 tons. The main reactor is analyzed to assess the required quantities of hydrogen and CO2. The production of hydrogen from the electrolysis of water is estimated, as well as the electrical power required and supplied by a large photovoltaic plant. The size of a realistic plant and its footprint are estimated. In addition, the mass of seawater to be desalinized and split in the electrolyser is calculated. The CO2 capture system is evaluate... [more]

The aim of this work is to identify the effect of the CaO phase as a CO2 sorbent and mayenite (Ca12Al14O33) as a stabilizing phase in a bi-functional material for CO2 capture in biomass syngas conditioning and cleaning at high temperature. The effect of different CaO weight contents is studied (0, 56, 85, 100 wt%) in sorbents synthesized by the wet mixing method. These high temperature solid sorbents are upgraded to bi-functional compounds by the addition of 3 or 6 wt% of nickel chosen as the metal active phase. N2 adsorption, X-ray diffraction, scanning electronic microscopy, temperature-programmed reduction analyses and CO2 sorption study were performed to characterize structural, textural, reducibility and sorption properties of bi-functional materials. Finally, sorption-enhanced reforming of toluene (chosen as tar model), of methane then of methane and toluene with bi-functional compounds were performed to study the best material to improve H2 content in a syngas, provided by steam... [more]

The production of blue hydrogen through sorption-enhanced processes has emerged as a suitable option to reduce greenhouse gas emissions. Sorption-enhanced steam−methane reforming (SESMR) is a process intensification of highly endothermic steam−methane reforming (SMR), ensured by in situ carbon capture through a solid sorbent, making hydrogen production efficient and more environmentally sustainable. In this study, a comprehensive energy model of SESMR was developed to carry out a detailed energy characterization of the process, with the aim of filling a current knowledge gap in the literature. The model was applied to a bench-scale multicycle SESMR/sorbent regeneration test to provide an energy insight into the process. Besides the experimental advantages of higher hydrogen concentration (90 mol% dry basis, 70 mol% wet basis) and performance of CO2 capture, the developed energy model demonstrated that SESMR allows for substantially complete energy self-sufficiency through the process.... [more]

Carbon dioxide (CO2) is one of the major atmospheric greenhouse gases (GHG). The continuous increase of CO2 concentration and its long atmospheric lifetime may cause long-term negative effects on the climate. It is important to develop technologies to capture and minimize those emissions into the atmosphere. The objective of this work is to design and study theoretically and experimentally a numbering-up/scale-out membrane microreactor in order to be used as a capture system. The main aim of the work is to obtain an even flow distribution at each plate of the reactor. Nearly uniform flow distribution was achieved at each layer of the numbering-up microreactor according to the carried-out CFD models. The maximum difference between the average velocities was less than 6% for both gas and liquid flows. To obtain better flow distribution into the microreactor, the radius of the inlet/outlet tube was optimized. Results from CFD and experimental simulations do not match, and slightly maldist... [more]

Energy need is predicted to increase by 48% in the next 30 years. Global warming resulting from the continuously increasing atmospheric CO2 concentration is becoming a serious and pressing issue that needs to be controlled. CO2 capture and storage/use (CCS/CCU) provide a promising route to mitigate the environmental consequences of CO2 emission from fossil fuel combustion. In recent years, hollow fiber membrane contactors are regarded as an advanced technique with several competitive advantages over conventional technologies such as easy scale-up, independent control of flow rates, more operational flexibility, absence of flooding and foaming as well as high interfacial area per unit volume. However, many factors such as the membrane material selection, proper choice of solvent, and membrane module design are critical to success. In this regard, this paper aims at covering all areas related to hollow fiber membranes, including membrane material, membrane modification, membrane surface... [more]

Michigan State University-2 (MSU-2) is notable potential adsorbent for carbon dioxide (CO2) due to its intrinsic properties, which include its highly interconnected three-dimensional (3D) wormhole-like framework structure, high specific surface area, and its large total pore volume, as well as its large amount of surface silanol hydroxyl groups, which facilitate the amine functionalization process. In this study, unfunctionalized MSU-2 was synthesized via a fluoride-assisted two-step process via the solution precipitation method, using Triton X-100 as the surfactant and tetraethylorthosilicate (TEOS) as the silica precursor. Then, the synthesized MSU-2 was functionalized using varying tetraethylenepentamine (TEPA) loadings of 20−60 wt%. The effect of different TEPA loadings on the properties and CO2 adsorption capacity of the MSU samples was investigated. Studies of the CO2 adsorption of the unfunctionalized and TEPA-functionalized MSU-2 samples was conducted at 40 °C and 1 bar of pres... [more]

-(2-Hydroxyethyl) piperazine (HEPZ) has a chemical structure similar to PZ and has less volatility. It is not easy to volatilize in a continuous operation device. It is studied to replace PZ as a promotor to increase the CO2 capture rate. This paper researches the lowest energy consumption and absorbent loss of HEPZ/H2O in the absorption-regeneration process, and compares it with another five amines, including PZ, MEA, 1-MPZ, AMP and DMEA. Based on the thermodynamic model, this work establishes a process simulation based on the equilibrium stage, assuming that all stages of the absorption and desorption towers reach thermodynamic equilibrium and CO2 recovery in the absorption tower is 90%. By optimizing the process parameters, the lowest thermodynamic energy consumption and absorbent loss of process operation are obtained. Our results show that HEPZ as a promotor to replace PZ and MEA has significant economic value. The lowest reboiler energy consumption of HEPZ with the optimal proces... [more]

The increasing concentration of anthropogenic CO2 in the atmosphere is causing a global environmental crisis, forcing significant reductions in emissions. Among the existing CO2 capture technologies, microalgae-guided sequestration is seen as one of the more promising and sustainable solutions. The present review article compares CO2 emissions in the EU with other global economies, and outlines EU’s climate policy together with current and proposed EU climate regulations. Furthermore, it summarizes the current state of knowledge on controlled microalgal cultures, indicates the importance of CO2 phycoremediation methods, and assesses the importance of microalgae-based systems for long-term storage and utilization of CO2. It also outlines how far microalgae technologies within the EU have developed on the quantitative and technological levels, together with prospects for future development. The literature overview has shown that large-scale take-up of technological solutions for the prod... [more]

Carbon capture, utilization, and storage (CCUS) is one of the key promising technologies that can reduce GHG emissions from those industries that generate CO2 as part of their production processes. Compared to other effective CO2 capture methods, the adsorption technique offers the possibility of reducing the costs of the process by setting solid sorbent with a high capacity of adsorption and easy regeneration and, also, controlling the performance of gas-solid contactor. In this work, an amine-functionalized mesoporous sorbent was used to capture CO2 emissions in a confined-fluidized bed. The adoption of a confined environment allows the establishment of a homogeneous expansion regime for the sorbent and allows to improve the exchange of matter and heat between gas and solid phase. The results illustrate how the different concentration of the solution adopted during the functionalization affects the adsorption capacity. That, measured as mg of CO2 per g of sorbent, was determined by b... [more]

The direct dry mineral carbonation of selected mining and industrial wastes, using carbon dioxide derived from combustion flue gas, was evaluated. Specifically, coal fly ash from two Australian brown coal-fired power plants, red mud from the refinement of bauxite into alumina, and diamond tailings were considered, due to their relevant residual alkali content. These materials were tested in a laboratory-scale fluidized bed reactor at different temperatures (300−450 °C), in a reactive environment that simulated the typical CO2 concentration in a combustion flue gas. The experimental results showed a low, but still appreciable, CO2 capture capacity for three of the tested materials, which appears to be more favorable in the lower temperature range and with relatively fast kinetics, indicating the practical relevance of the process. One of the fly ashes exhibited a different behavior; starting at 350 °C, the sorbent began to release CO2, rather than absorb it. This suggested that the sorb... [more]

In the context of climate change and the reduction in CO2 emissions from fossil fuel combustion, the integration of CO2 capture technologies in steam power plants is a key solution. The aim of this study was to analyze the use of ammonia, at different mass concentrations, in capturing post-combustion CO2 in a coal-fired power station and comparing it with the reference 30% MEA case. In this regard, a multi-criteria model was developed to establish the optimal solvent used, considering the least impact on technical performance, economic, and environmental indicators. As a result, the lowest CO2 capture cost was obtained for the CO2 capture process based on 7% NH3, with 59.07 €/tCO2. Integration of the CO2 capture process is more economically viable when the CO2 emissions tax is higher than 70 €/tCO2 for 7% NH3 and 15% NH3, 80 €/tCO2 for 5% NH3 and 30% MEA, and 90 €/tCO2 for 2% NH3. Regarding the overall efficiency, the energy penalty associated with the CO2 capture process integration v... [more]

Carbon Capture and Storage (CCS) technology has attracted increasing attention as global climate change accelerates. Carbon dioxide removal processes under development include pressure swing adsorption (PSA) and chemical absorption using amine solvents. In this paper, an ammonia solvent, which is relatively inexpensive and has good material properties, was used instead of amines in the carbon dioxide removal process simulation as a chemical absorption method. This simulation used the eNRTL thermodynamics model which has the advantage of predicting ions in the liquid phase in Aspen Plus. A case study (Case Study 1) was conducted to verify the validity of the thermodynamic model. The purpose of this research was to find the operating conditions to eliminate more than 90% of the carbon dioxide contained in the flue gas from coal-fired power stations, and to lower heat duty and operating cost conditions. A second case study (Case Study 2) was conducted to find the operating conditions by c... [more]

A novel process path is proposed to produce glycolic acid (GA) from CO2 as the feedstock, including CO2 capture, power-to-hydrogen, CO2 hydrogenation to methanol, methanol oxidation to formaldehyde, and formaldehyde carbonylation units. The bottlenecks are discussed from the perspectives of carbon utilization, CO2 emissions, total site energy integration, and techno-economic analysis. The carbon utilization ratio of the process is 82.5%, and the CO2 capture unit has the largest percentage of discharge in carbon utilization. Among the indirect emissions of each unit, the CO2 hydrogenation to methanol has the largest proportion of indirect carbon emissions, followed by the formaldehyde carbonylation to glycolic acid and the CO2 capture. After total site energy integration, the utility consumption is 1102.89 MW for cold utility, 409.67 MW for heat utility, and 45.98 MW for power. The CO2 hydrogenation to methanol makes the largest contribution to utility consumption due to the multi-stage... [more]

Methanol is considered a sustainable alternative energy source due to its ease of storage and high-octane rating. However, the conventional methanol production process is accompanied by resource consumption and significant greenhouse gas emissions. The electrochemical reaction of electrochemically reacted hydrogen (H2) with captured carbon dioxide (CO2) offers an alternative route to methanol production. This paper presents a new green poly-generation system consisting of a parabolic trough solar collector (PTC) unit, an organic Rankine cycle (ORC) unit, a CO2 capture unit, an alkaline electrolysis unit, a green methanol synthesis and distillation unit, and a double-effect lithium bromide absorption refrigeration (ARC) unit. The system mainly produced 147.4 kmol/h of methanol at 99.9% purity, 283,500 kmol/h of domestic hot water, and a cooling load of 1341 kW. A total 361.34 MW of thermal energy was supplied to the ORC by the PTC. The alkaline electrolysis unit generated 464.2 kmol/h o... [more]

This paper aims to evaluate different design configurations of a combined heat and power (CHP) plant with post-combustion CO2 capture. Three cases are involved in this study: case 1 consists of three trains and each train has a configuration of one gas turbine with a heat recovery steam generator (HRSG); case 2 consists of three trains and one steam turbine; and case 3 consists of only two trains. The third case presented the highest CHP efficiency of 72.86% with 511.8 MW net power generation. After selecting the optimum configuration, a parabolic-trough collector (PTC) was incorporated to generate additional saturated steam at 3.5 bar for the capture plant, adding greater flexibility to the CHP because more steam was available. In addition, the efficiency of the cycle increased from 72.86% to 80.18%. Although case 2 presented lower efficiency than case 3, it has a steam turbine which brings the possibility of increasing the amount of electricity instead of steam production. When the P... [more]

The serious environmental issues associated with CO2 emissions have triggered the search for energy efficient processes and CO2 capture technologies to control the amount of gas released into the atmosphere. One of the suitable techniques is CO2 adsorption using functionalized sorbents. In this study, a functionalized activated carbon (AC) material was developed via the wet impregnation technique. The AC was synthesized from a rubber seed shell (RSS) precursor using chemical activation and was later impregnated with different ratios of [bmpy][Tf2N] ionic liquid (IL). The AC was successfully functionalized with IL as confirmed by FTIR and Raman spectroscopy analyses. Incorporation of IL resulted in a reduction in the surface area and total pore volume of the parent adsorbent. Bare AC showed the largest SBET value of 683 m2/g, while AC functionalized with the maximum amount of IL showed 14 m2/g. A comparative analysis of CO2 adsorption data revealed that CO2 adsorption performance of AC... [more]

Example Aspen Plus chemical process simulations used in the book Exergy Tables: A Comprehensive Set of Exergy Values to Streamline Energy Efficiency Analysis, by Lingyan Deng, Thomas A. Adams II, and Truls Gundersen (McGraw-Hill Education, 2023). The examples are:

1. Medium-pressure steam generation using a natural-gas powered boiler
2. Medium-pressure steam generation using a natural-gas powered boiler with an economizer
3. Medium-pressure steam generation using an off-gas powered boiler
4. Postcombustion CO2 capture using diglycolamine (DGA) with CCS

Note, stream conditions may vary slightly from those in the book when simulated with different versions of the software.

Files are Aspen Plus v12.1, but should be openable on any version 12.1 or later.

Mitigation of carbon emissions is an important step to achieve the climate change goals. Amine-based post-combustion CO2 capture (PCC) process is a promising technology, and many commercial projects have been developed based on different capture mechanisms governing in various carbon capture and storage (CCS) processes. The thermally regenerative amine-based PCC is a traditional technology, which consists of an absorber to capture CO2 from the flue gas and a desorber to strip CO2 from the CO2-rich. Although there have been substantial improvements in the industrial applications of amines technology, further developments are still required owing to significant energy requirement, high capital cost, and amine degradation. One of the most critical issues in the amine-based PCC process is the degradation of solvent, which occurs by the transformation of amines into other chemical components by thermal degradation and oxidative degradation. In the thermal degradation, the amines react with... [more]

The coal to ethylene glycol (CTEG) process has drawn much attention due to the serious conflict between supply and demand of ethylene glycol in China. However, it is inevitably accompanied by the problem of high CO2 emissions. Carbon capture is one of the most promising potential effective ways to address this issue. However, the CTEG process, integrated with carbon capture technology, will lead to energy and economic penalties. Thus, a comprehensive evaluation of CTEG process with different CO2 capture technologies is urgently needed. This study analyzed the technoeconomic performance of four CO2 capture alternatives for the CTEG process: Rectisol, mono-ethanol amine (MEA), chilled ammonia process (CAP) and dimethyl carbonate (DMC) technologies. Results show the energy consumption of CO2 capture of the Rectisol process is the lowest, 1.88 GJ/tCO2, followed by the DMC process, 2.10 GJ/tCO2, the CAP process, 3.64 GJ/tCO2, and the MEA process, 5.20 GJ/tCO2. The CO2 capture cost of the Re... [more]

Hydrogen from natural gas with CO2 capture can be a key transition technology to a low carbon energy system due to the abundance of natural gas and the possibility to increase the production capacity quickly. However, it is necessary to achieve both a high energy efficiency and a high CO2 capture ratio to be a viable option. The liquefaction of CO2 is one promising separation technology as it provides the captured CO2 in a transportable format. This paper therefore proposes a hydrogen production process with integrated CO2 liquefaction. Efficiencies of up to 84.7 % (Based on the higher heating value) and CO2 capture ratios of up to 97.2 % can be achieved. One advantage of the utilization of CO2 liquefaction as separation technology is furthermore the possibility to incorporate a partial recycle of the flue gas from the separation to the water–gas shift reaction, increasing both energy efficiency and carbon capture ratio.