Records with Keyword: Carbon Dioxide Capture
Showing records 1 to 25 of 80. [First] Page: 1 2 3 4 Last
Environmental and Comparative Assessment of Integrated Gasification Gas Cycle with CaO Looping and CO2 Adsorption by Activated Carbon: A Case Study of the Czech Republic
Kristína Zakuciová, Ana Carvalho, Jiří Štefanica, Monika Vitvarová, Lukáš Pilař, Vladimír Kočí
March 29, 2023 (v1)
Subject: Environment
Keywords: activated carbon, carbon capture economy, Carbon Dioxide Capture, environmental impacts, IGCC
The Czech Republic is gradually shifting toward a low-carbon economy. The transition process requires measures that will help to contain energy production and help to reduce emissions from the coal industry. Viable measures are seen in carbon capture technologies (CCTs). The main focus is on the environmental and economic comparison of two innovative CCTs that are integrated in the operational Czech energy units. The assessed scenarios are (1) the scenario of pre-combustion CO2 capture integrated into the gasification combined cycle (IGCC-CaL) and (2) the scenario of post-combustion capture by adsorption of CO2 by activated carbon (PCC-A). An environmental assessment is performed through a life-cycle assessment method and compares the systems in the phase of characterization, normalization, and relative contribution of the processes to the environmental categories. Economic assessment compares CCT via capture and avoided costs of CO2 and their correlation with CO2 allowance market tren... [more]
The Zr-Doped CaO CO2 Sorbent Fabricated by Wet High-Energy Milling
Vyacheslav V. Rodaev, Svetlana S. Razlivalova
March 29, 2023 (v1)
Keywords: CaO, Carbon Dioxide Capture, high-energy milling, sorbent, ZrO2
We fabricated the Zr-doped CaO sorbent for high-temperature CO2 capture by the wet high-energy co-milling of calcium carbonate and natural zirconium dioxide (baddeleyite) for the first time. The morphology of the material was examined by scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Its CO2 uptake capacity was determined using thermogravimetric analysis. After 50 carbonation−calcination cycles, the Zr-doped CaO sorbent characterized by a high enough CO2 uptake capacity of 8.6 mmol/g and unchanged microstructure due to CaZrO3 nanoparticles uniformly distributed in the CaO matrix to prevent CaCO3 sintering under carbonation. The proposed easy-to-implement CaO-based sorbents fabrication technique is promising for industrial application.
Design and Analysis of Novel CO2 Conditioning Process in Ship-Based CCS
Wentao Gong, Eryk Remiezowicz, Philip Loldrup Fosbøl, Nicolas von Solms
March 28, 2023 (v1)
Keywords: Carbon Dioxide Capture, CCS hub Dunkirk, CO2 conditioning, CO2 liquefaction, DMXTM process
In this work, CO2 conditioning processes for ship-based CCS sequestration are modelled using the software APSEN HYSYS V11. This study uses the captured CO2 gas from the 3D project as the feed. The feed stream contains water, H2S, and CO as contaminants. The purification processes for dehydration, desulfurization, and CO removal are reviewed. Two liquefaction approaches, the open-cycle and the closed-cycle liquefaction, are modelled and compared for transport pressures 7 and 15 bar. It is found that the energy requirement of the open-cycle process is higher than that of the closed-cycle liquefaction process. For the closed-cycle design, two refrigerants, ammonia and propane, are considered. Results show that the energy requirement of the process using ammonia is lower than that of propane. When comparing the two transport pressures, it is found that liquefaction at 15 bar requires less energy than 7 bar. On top of that, both refrigerants are unsuited for the liquefaction of CO2 at 7 bar... [more]
Study of Amine Functionalized Mesoporous Carbon as CO2 Storage Materials
Muhamad Faisal, Afif Zulfikar Pamungkas, Yuni Krisyuningsih Krisnandi
March 28, 2023 (v1)
Subject: Materials
Keywords: Adsorption, amine-based adsorbents, Carbon Dioxide Capture, ethylenediamine, mesoporous carbon, triethylenetetramine
Carbon sequestration via the carbon capture and storage (CCS) method is one of the most useful methods of lowering CO2 emissions in the atmosphere. Ethylenediamine (EDA)- and triethylenetetramine (TETA)-modified mesoporous carbon (MC) has been successfully prepared as a CO2 storage material. The effect of various concentrations of EDA or TETA added to MC, as well as activated carbon (AC), on their CO2 adsorption capacity were investigated using high-purity CO2 as a feed and a titration method to quantitatively measure the amount of adsorbed CO2. The results showed that within 60 min adsorption time, MCEDA49 gave the highest CO2 capacity adsorption (19.68 mmol/g), followed by MC-TETA30 (11.241 mol/g). The improvement of CO2 adsorption capacity at low TETA loadings proved that the four amine functional groups in TETA gave an advantage to CO2 adsorption. TETA-functionalized MC has the potential to be used as a CO2 storage material at a low concentration. Therefore, it is relatively benign... [more]
Techno-Economic Analysis of Pressurized Oxy-Fuel Combustion of Petroleum Coke
Hachem Hamadeh, Sannan Y. Toor, Peter L. Douglas, S. Mani Sarathy, Robert W. Dibble, Eric Croiset
March 27, 2023 (v1)
Keywords: AspenPlusTM simulation, Carbon Dioxide Capture, oxy-fuel combustion, Petroleum Coke, pressurized combustion
Petroleum coke (petcoke) is a by-product of heavy petroleum refining, with heating values comparable to that of coal. It is readily available in oil-producing countries such as the United States of America (USA) and the Kingdom of Saudi Arabia (KSA) at minimum costs and can be used as an inexpensive fossil fuel for power generation. Oxy-petcoke combustion is an attractive CO2 capture option as it avoids the use of additional absorption units and chemicals, and results in a CO2 + H2O flue gas stream that is compressed and dehydrated in a CO2 capture and purification unit (CO2CPU). The additional cost of the CO2CPU can be reduced through high pressure combustion. Hence, this paper reports a techno-economic analysis of an oxy-petcoke plant with CO2 capture simulated at pressures between 1 and 15 bars in Aspen PlusTM based on USA and KSA scenarios. Operating at high pressures leads to reduced equipment sizes and numbers of units, specifically compressors in CO2CPU, resulting in increased e... [more]
Efficient Production of Clean Power and Hydrogen Through Synergistic Integration of Chemical Looping Combustion and Reforming
Mohammed N. Khan, Schalk Cloete, Shahriar Amini
March 27, 2023 (v1)
Keywords: Carbon Dioxide Capture, chemical looping combustion, energy penalty, Hydrogen, natural gas combined cycle, power plant
Chemical looping combustion (CLC) technology generates power while capturing CO2 inherently with no direct energy penalty. However, previous studies have shown significant energy penalties due to low turbine inlet temperature (TIT) relative to a standard natural gas combined cycle plant. The low TIT is limited by the oxygen carrier material used in the CLC process. Therefore, in the current study, an additional combustor is included downstream of the CLC air reactor to raise the TIT. The efficient production of clean hydrogen for firing the added combustor is key to the success of this strategy. Therefore, the highly efficient membrane-assisted chemical looping reforming (MA-CLR) technology was selected. Five different integrations between CLC and MA-CLR were investigated, capitalizing on the steam in the CLC fuel reactor outlet stream to achieve highly efficient reforming in MA-CLR. This integration reduced the energy penalty as low as 3.6%-points for power production only (case 2) an... [more]
Techno-Economic Assessment of a Combined Heat and Power Plant Integrated with Carbon Dioxide Removal Technology: A Case Study for Central Poland
Paweł Gładysz, Anna Sowiżdżał, Maciej Miecznik, Maciej Hacaga, Leszek Pająk
March 27, 2023 (v1)
Keywords: Biomass, Carbon Dioxide Capture, CO2 enhanced geothermal systems, combined heat and power, negative emission technologies, supercritical CO2 power cycles, utilization and storage
The objective of this study is to assess the techno-economic potential of the proposed novel energy system, which allows for negative emissions of carbon dioxide (CO2). The analyzed system comprises four main subsystems: a biomass-fired combined heat and power plant integrated with a CO2 capture and compression unit, a CO2 transport pipeline, a CO2-enhanced geothermal system, and a supercritical CO2 Brayton power cycle. For the purpose of the comprehensive techno-economic assessment, the results for the reference biomass-fired combined heat and power plant without CO2 capture are also presented. Based on the proposed framework for energy and economic assessment, the energy efficiencies, the specific primary energy consumption of CO2 avoidance, the cost of CO2 avoidance, and negative CO2 emissions are evaluated based on the results of process simulations. In addition, an overview of the relevant elements of the whole system is provided, taking into account technological progress and tec... [more]
Effect of Various Parameters on the Thermal Stability and Corrosion of CO2-Loaded Tertiary Amine Blends
Usman Shoukat, Hanna Katariina Knuutila
March 27, 2023 (v1)
Keywords: amine concentration, Carbon Dioxide Capture, CO2 loading, corrosivity, tertiary amines, thermal stability
In this study, the thermal stability and corrosivity of various CO2-loaded tertiary amine blends in both aqueous and non-aqueous form in stainless steel cylinders were studied for combined acid gas and water removal. The thermal stability was measured from the remaining amine concentration and the corrosivity was measured from the amount of various metals in blends using titration and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The experimental data were used to calculate the rate constants of amine group loss. The developed model represented the experimental data very well. Solvent change from H2O to triethylene glycol (TEG) in blends decreased the thermal stability and vice versa for corrosivity. The amine stability was increased when contact with stainless steel was reduced. An increase in the amine concentration or CO2 loading at constant temperature decreased the thermal stability and vice versa for corrosivity.
A Preliminary Techno-Economic Analysis on the Calcium Looping Process with Simultaneous Capture of CO2 and SO2 from a Coal-Based Combustion Power Plant
Antonio Coppola, Fabrizio Scala
March 24, 2023 (v1)
Keywords: calcium looping, Carbon Dioxide Capture, coal-based power plant, desulphurization, Technoeconomic Analysis
The increase of capital investments and operation and maintenance (O&M) costs represents a current limitation to the diffusion of carbon capture systems for the clean combustion of fossil fuels. However, post-combustion systems, such as calcium looping (CaL), for CO2 capture from flue gas are the most attractive carbon capture systems since they can be installed at new plants and retrofitted into existing power plants. This work investigates the pros and cons of employing a calcium looping system for CO2 capture and also as a desulphurization unit. A preliminary techno-economic analysis was carried out comparing a base case consisting of a coal-based power plant of about 550MWe with a desulphurization unit (Case 1), the same plant but with a CaL system added for CO2 capture (Case 2), or the same plant but with a CaL system for simultaneous capture of CO2 and SO2 and the removal of the desulphurization unit (Case 3). Case 2 resulted in a 67% increase of capital investment with respect t... [more]
Biomass Thermochemical Conversion via Pyrolysis with Integrated CO2 Capture
Małgorzata Sieradzka, Ningbo Gao, Cui Quan, Agata Mlonka-Mędrala, Aneta Magdziarz
March 23, 2023 (v1)
Keywords: Biomass, CaO solid sorbent, Carbon Dioxide Capture, chars, Hydrogen, physicochemical structure, pine wood, pyrolysis, Syngas
The presented work is focused on biomass thermochemical conversion with integrated CO2 capture. The main aim of this study was the in-depth investigation of the impact of pyrolysis temperature (500, 600 and 700 °C) and CaO sorbent addition on the chemical and physical properties of obtained char and syngas. Under the effect of the pyrolysis temperature, the properties of biomass chars were gradually changed, and this was confirmed by examination using thermal analysis, scanning electron microscopy, X-ray diffraction, and porosimetry methods. The chars were characterised by a noticeable carbon content (two times at 700 °C) resulting in a lower O/C ratio. The calculated combustion indexes indicated the better combustible properties of chars. In addition, structural morphology changes were observed. However, the increasing pyrolysis temperature resulted in changes of solid products; the differences of char properties were not significant in the range of 500 to 700 °C. Syngas was analysed... [more]
A Carbide Slag-Based, Ca12Al14O33-Stabilized Sorbent Prepared by the Hydrothermal Template Method Enabling Efficient CO2 Capture
Xiaotong Ma, Yingjie Li, Yi Qian, Zeyan Wang
March 21, 2023 (v1)
Keywords: calcium aluminates, calcium looping, carbide slag, Carbon Dioxide Capture
Calcium looping is a promising technology to capture CO2 from the process of coal-fired power generation and gasification of coal/biomass for hydrogen production. The decay of CO2 capture activities of calcium-based sorbents is one of the main problems holding back the development of the technology. Taking carbide slag as a main raw material and Ca12Al14O33 as a support, highly active CO2 sorbents were prepared using the hydrothermal template method in this work. The effects of support ratio, cycle number, and reaction conditions were evaluated. The results show that Ca12Al14O33 generated effectively improves the cyclic stability of CO2 capture by synthetic sorbents. When the Al2O3 addition is 5%, or the Ca12Al14O33 content is 10%, the synthetic sorbent possesses the highest cyclic CO2 capture performance. Under harsh calcination conditions, the CO2 capture capacity of the synthetic sorbent after 30 cycles is 0.29 g/g, which is 80% higher than that of carbide slag. The superiority of t... [more]
On the Integration of CO2 Capture Technologies for an Oil Refinery
Vadim Fetisov, Adam M. Gonopolsky, Maria Yu. Zemenkova, Schipachev Andrey, Hadi Davardoost, Amir H. Mohammadi, Masoud Riazi
March 20, 2023 (v1)
Keywords: Carbon Dioxide Capture, CCUS, oil refinery, Residual Oil Zones (ROZ)
This study determines and presents the capital and operating costs imposed by the use of CO2 capture technologies in the refining and petrochemical sectors. Depending on the refining process and the CO2 capture method, CO2 emissions costs of EUR 30 to 40 per ton of CO2 can be avoided. Advanced low-temperature CO2 capture technologies for upgrading oxyfuel reformers may not provide any significant long-term and short-term benefits compared to conventional technologies. For this reason, an analysis was performed to estimate the CO2 reduction potential for the oil and gas industries using short- and long-term ST/MT technologies, was arriving at a reduction potential of about 0.5−1 Gt/yr. The low cost of CO2 reduction is a result of the good integration of CO2 capture into the oil production process. The results show that advanced gasoline fraction recovery with integrated CO2 capture can reduce the cost of producing petroleum products and reduce CO2 emissions, while partial CO2 capture ha... [more]
Direct Study of CO2 Capture Efficiency during Microalgae Arthrospira platensis Cultivation at High CO2 Concentrations
Elizaveta A. Chunzhuk, Anatoly V. Grigorenko, Nadezhda I. Chernova, Sofya V. Kiseleva, Kirill G. Ryndin, Oleg S. Popel, Sergey Ya Malaniy, Olga V. Slavkina, Fabio de Farias Neves, Lijian Leng, Vinod Kumar, Mikhail S. Vlaskin
March 20, 2023 (v1)
Subject: Biosystems
Keywords: Arthrospira platensis, Carbon Dioxide Capture, direct study, high CO2 concentrations, microalgae cultivation, photobioreactor, Spirulina platensis
Direct study of CO2 capture efficiency during microalgae Arthrospira platensis cultivation at high CO2 concentrations was carried out. Microalgae were grown in a 90 L photobioreactor on Zarrouk’s medium prepared with distilled water. Three 15-day experiments were carried out with different initial CO2 concentrations: 1, 5, and 9 vol.%. During the experiments, both the change in the optical density of the microalgae suspension and the direct change in the CO2 concentration in the chamber were measured. The maximum decrease in CO2 concentration due to the growth of microalgae was 0.10 vol.% (CO2)/day in the experiment with an initial CO2 concentration of 5 vol.%. Growth rate of biomass density was 79.4, 76.3, and 48.4 (mg/L)/day at 1, 5, and 9 vol.% CO2 concentrations, respectively. During the experiment with initial CO2 concentrations of 1 and 5 vol.%., pH of the culture medium was increased, but pH was decreased from 9.2 to 8.8 at 9 vol.%. In general, good viability (high quality of bi... [more]
Techno-Economic Analysis of the Oxy-Fuel Combustion Power Cycles with Near-Zero Emissions
Vladimir Kindra, Andrey Rogalev, Evgeny Lisin, Sergey Osipov, Olga Zlyvko
March 9, 2023 (v1)
Keywords: Carbon Dioxide Capture, carbon dioxide emission quotes payment, near-zero emission technologies, oxy-fuel combustion power cycles, technical and economic assessment, TPP
This paper is devoted to improvement of environmental safety in hydrocarbon-firing TPPs. Despite the development of renewable power sources, the number of traditional power production facilities continues its growth. The toxic emission mitigation in traditional TPPs has been deeply investigated, but the problem of greenhouse gas atmospheric emissions is of topical interest. Oxy-fuel technology reduces CO2 emissions and is highly efficient and environmentally safe. Also, it requires relatively low capital investments. Thermal efficiency analysis shows that the Allam cycle facilities have the best efficiency. Their thermodynamic parameters can be optimized with minimal primary costs and capital investments. This newly developed analysis was used to compare the investment efficiency of projects for the buildup of oxy-fuel and combined cycle facilities. Without emission quote payments, the NPV of combined cycle projects is 16% higher, as well as having a lower DPP. The electricity producti... [more]
Kinetic and Thermodynamic Analysis of High-Pressure CO2 Capture Using Ethylenediamine: Experimental Study and Modeling
Josselyne A. Villarroel, Alex Palma-Cando, Alfredo Viloria, Marvin Ricaurte
March 8, 2023 (v1)
Keywords: Carbon Dioxide Capture, ethylenediamine, high-pressure system, kinetics, Modelling, thermodynamic analysis
One of the alternatives to reduce CO2 emissions from industrial sources (mainly the oil and gas industry) is CO2 capture. Absorption with chemical solvents (alkanolamines in aqueous solutions) is the most widely used conventional technology for CO2 capture. Despite the competitive advantages of chemical solvents, the technological challenge in improving the absorption process is to apply alternative solvents, reducing energy demand and increasing the CO2 captured per unit of solvent mass. This work presents an experimental study related to the kinetic and thermodynamic analysis of high-pressure CO2 capture using ethylenediamine (EDA) as a chemical solvent. EDA has two amine groups that can increase the CO2 capture capacity per unit of solvent. A non-stirred experimental setup was installed and commissioned for CO2 capture testing. Tests of the solubility of CO2 in water were carried out to validate the experimental setup. CO2 capture testing was accomplished using EDA in aqueous soluti... [more]
Effect of the Presence of HCl on Simultaneous CO2 Capture and Contaminants Removal from Simulated Biomass Gasification Producer Gas by CaO-Fe2O3 Sorbent in Calcium Looping Cycles
Forogh Dashtestani, Mohammad Nusheh, Vilailuck Siriwongrungson, Janjira Hongrapipat, Vlatko Materic, Alex C. K. Yip, Shusheng Pang
March 6, 2023 (v1)
Keywords: calcium looping, CaO-Fe2O3 sorbent, Carbon Dioxide Capture, contaminant removal
This study investigated the effect of HCl in biomass gasification producer gas on the CO2 capture efficiency and contaminants removal efficiency by CaO-Fe2O3 based sorbent material in the calcium looping process. Experiments were conducted in a fixed bed reactor to capture CO2 from the producer gas with the combined contaminants of HCl at 200 ppmv, H2S at 230 ppmv, and NH3 at 2300 ppmv. The results show that with presence of HCl in the feeding gas, sorbent reactivity for CO2 capture and contaminants removal was enhanced. The maximum CO2 capture was achieved at carbonation temperatures of 680 °C, with efficiencies of 93%, 92%, and 87%, respectively, for three carbonation-calcination cycles. At this carbonation temperature, the average contaminant removal efficiencies were 92.7% for HCl, 99% for NH3, and 94.7% for H2S. The outlet contaminant concentrations during the calcination process were also examined which is useful for CO2 reuse. The pore structure change of the used sorbent materi... [more]
An Electrochemical Platform for the Carbon Dioxide Capture and Conversion to Syngas
Alessio Mezza, Angelo Pettigiani, Nicolò B. D. Monti, Sergio Bocchini, M. Amin Farkhondehfal, Juqin Zeng, Angelica Chiodoni, Candido F. Pirri, Adriano Sacco
March 6, 2023 (v1)
Keywords: carbon capture and utilization, Carbon Dioxide Capture, CO2 conversion, electrochemical capture, electrodialysis, Syngas
We report on a simple electrochemical system able to capture gaseous carbon dioxide from a gas mixture and convert it into syngas. The capture/release module is implemented via regeneration of NaOH and acidification of NaHCO3 inside a four-chamber electrochemical flow cell employing Pt foils as catalysts, while the conversion is carried out by a coupled reactor that performs electrochemical reduction of carbon dioxide using ZnO as a catalyst and KHCO3 as an electrolyte. The capture module is optimized such that, powered by a current density of 100 mA/cm2, from a mixture of the CO2−N2 gas stream, a pure and stable CO2 outlet flow of 4−5 mL/min is obtained. The conversion module is able to convert the carbon dioxide into a mixture of gaseous CO and H2 (syngas) with a selectivity for the carbon monoxide of 56%. This represents the first all-electrochemical system for carbon dioxide capture and conversion.
Environmental and Energetic Valorization of Renewable Resources
Attilio Converti
March 6, 2023 (v1)
Subject: Environment
Keywords: Biomass, biosurfactant, Carbon Dioxide Capture, contaminated soil, electricity, food waste, fuel cell, hydroelectric plant, power generation, pyrolysis
This Editorial provides an overview of the 13 papers published in the Special Issue Environmental and Energetic Valorization of RenewableResources belonging to Section B: Sustainable Energy of the Energies journal, five being review papers and the remaining being scientific articles.
Transforming Plastic Waste into Porous Carbon for Capturing Carbon Dioxide: A Review
Farihahusnah Hussin, Mohamed Kheireddine Aroua, Mohd Azlan Kassim, Umi Fazara Md. Ali
March 3, 2023 (v1)
Subject: Environment
Keywords: Adsorption, Carbon Dioxide Capture, carbon emission and utilization, char, plastic waste, pyrolysis
Plastic waste generation has increased dramatically every day. Indiscriminate disposal of plastic wastes can lead to several negative impacts on the environment, such as a significant increase in greenhouse gas emissions and water pollution. Therefore, it is wise to think of other alternatives to reduce plastic wastes without affecting the environment, including converting them into valuable products using effective methods such as pyrolysis. Products from the pyrolysis process encompassing of liquid, gas, and solid residues (char) can be turned into beneficial products, as the liquid product can be used as a commercial fuel and char can function as an excellent adsorbent. The char produced from plastic wastes could be modified to enhance carbon dioxide (CO2) adsorption performance. Therefore, this review attempts to compile relevant knowledge on the potential of adsorbents derived from waste plastic to capture CO2. This review was performed in accordance with PRISMA guidelines. The pl... [more]
CO2 Capture from IGCC by Low-Temperature Synthesis Gas Separation
David Berstad, Geir Skaugen, Simon Roussanaly, Rahul Anantharaman, Petter Nekså, Kristin Jordal, Stian Trædal, Truls Gundersen
March 3, 2023 (v1)
Keywords: Carbon Dioxide Capture, CCS, cryogenic, IGCC, low-temperature, precombustion
Capture conditions for CO2 vary substantially between industrial point sources. Depending on CO2 fraction and pressure level, different capture technologies will be required for cost- and energy-efficient decarbonisation. For decarbonisation of shifted synthesis gas from coal gasification, several studies have identified low-temperature CO2 capture by condensation and phase separation as an energy- and cost-efficient option. In the present work, a process design is proposed for low-temperature CO2 capture from an Integrated Gasification Combined Cycle (IGCC) power plant. Steady-state simulations were carried out and the performance of the overall process, as well as major process components, were investigated. For the baseline capture unit layout, delivering high-pressure CO2 at 150 bar, the net specific power requirement was estimated to 273 kJe/kgCO2, and an 85% CO2 capture ratio was obtained. The impact of 12 different process parameters was studied in a sensitivity analysis, the re... [more]
Cost and Emissions Reduction in CO2 Capture Plant Dependent on Heat Exchanger Type and Different Process Configurations: Optimum Temperature Approach Analysis
Solomon Aforkoghene Aromada, Nils Henrik Eldrup, Lars Erik Øi
March 3, 2023 (v1)
Keywords: Carbon Dioxide Capture, MEA, process simulation, Technoeconomic Analysis, waste heat
The performance of a plate heat exchanger (PHE), in comparison with the conventional shell and tube types, through a trade-off analysis of energy cost and capital cost resulting from different temperature approaches in the cross-exchanger of a solvent-based CO2 capture process, was evaluated. The aim was to examine the cost reduction and CO2 emission reduction potentials of the different heat exchangers. Each specific heat exchanger type was assumed for the cross-exchanger, the lean amine cooler and the cooler to cool the direct contact cooler’s circulation water. The study was conducted for flue gases from a natural-gas combined-cycle power plant and the Brevik cement plant in Norway. The standard and the lean vapour compression CO2 absorption configurations were used for the study. The PHE outperformed the fixed tube sheet shell and tube heat exchanger (FTS-STHX) and the other STHXs economically and in emissions reduction. The optimal minimum temperature approach for the PHE cases ba... [more]
Numerical Analysis of VPSA Technology Retrofitted to Steam Reforming Hydrogen Plants to Capture CO2 and Produce Blue H2
Mauro Luberti, Alexander Brown, Marco Balsamo, Mauro Capocelli
March 2, 2023 (v1)
Keywords: blue H2, Carbon Dioxide Capture, PSA tail gas, steam methane reforming, vacuum pressure swing adsorption
The increasing demand for energy and commodities has led to escalating greenhouse gas emissions, the chief of which is represented by carbon dioxide (CO2). Blue hydrogen (H2), a low-carbon hydrogen produced from natural gas with carbon capture technologies applied, has been suggested as a possible alternative to fossil fuels in processes with hard-to-abate emission sources, including refining, chemical, petrochemical and transport sectors. Due to the recent international directives aimed to combat climate change, even existing hydrogen plants should be retrofitted with carbon capture units. To optimize the process economics of such retrofit, it has been proposed to remove CO2 from the pressure swing adsorption (PSA) tail gas to exploit the relatively high CO2 concentration. This study aimed to design and numerically investigate a vacuum pressure swing adsorption (VPSA) process capable of capturing CO2 from the PSA tail gas of an industrial steam methane reforming (SMR)-based hydrogen p... [more]
Branched versus Linear Structure: Lowering the CO2 Desorption Temperature of Polyethylenimine-Functionalized Silica Adsorbents
Jannis Hack, Seraina Frazzetto, Leon Evers, Nobutaka Maeda, Daniel M. Meier
March 2, 2023 (v1)
Subject: Materials
Keywords: Carbon Dioxide Capture, polyethylenimine, regeneration temperature
Lowering the regeneration temperature for solid CO2-capture materials is one of the critical tasks for economizing CO2-capturing processes. Based on reported pKa values and nucleophilicity, we compared two different polyethylenimines (PEIs): branched PEI (BPEI) and linear PEI (LPEI). LPEI outperformed BPEI in terms of adsorption and desorption properties. Because LPEI is a solid below 73−75 °C, even a high loading amount of LPEI can effectively adsorb CO2 without diffusive barriers. Temperature-programmed desorption (TPD) demonstrated that the desorption peak top dropped to 50.8 °C for LPEI, compared to 78.0 °C for BPEI. We also revisited the classical adsorption model of CO2 on secondary amines by using in situ modulation excitation IR spectroscopy, and proposed a new adsorption configuration, R1(R2)-NCOOH. Even though LPEI is more expensive than BPEI, considering the long-term operation of a CO2-capturing system, the low regeneration temperature makes LPEI attractive for industrial a... [more]
Hydrate-Based Separation for Industrial Gas Mixtures
Muhammad Khan, Pramod Warrier, Cornelis Peters, Carolyn Koh
March 2, 2023 (v1)
Keywords: Carbon Dioxide Capture, gas hydrates, gas separation, Phase Equilibria, process design, sour gases
The removal of acidic gases and impurities from gas mixtures is a critical operation in the oil and gas industry. Several separation techniques, e.g., cryogenic fractionation, polymeric membranes, zeolites, and metal−organic frameworks, are employed to treat gas mixtures depending upon the nature of separation and contaminants present in the gas mixtures. However, removing N2, H2, H2S, and CO2 contents from industrial gas mixtures is a challenging step due to economic factors, high energy consumption, and effective separation. Hydrate-based separation for selective gas removal is a promising and efficient separation technique over a range of temperatures, pressures, and acidic gas contents. The enclathration of CO2, H2, N2, H2S, and other natural gas constituents effectively removes acidic gases and other contaminants from process gas streams. This work presents a novel process design to remove acidic gases and other contaminants from industrial waste gases and natural gas mixtures to... [more]
Decay on Cyclic CO2 Capture Performance of Calcium-Based Sorbents Derived from Wasted Precursors in Multicycles
Dehong Gong, Zhongxiao Zhang, Ting Zhao
March 1, 2023 (v1)
Keywords: calcium looping, Carbon Dioxide Capture, carbonation reaction, thermogravimetric analysis
In order to obtain the cheap waste calcium-based sorbent, three wasted CaCO3 precursors, namely carbide slag, chicken eggshells, and analytical reagent-grade calcium carbonate, were selected and prepared at 700 °C to form calcium-based sorbents for CO2 capture. TGA was used to test the CO2 uptake performance of each calcium-based sorbent in 20 cycles. To identify the decay mechanism of CO2 uptake with an increasing number of cycles, all calcium-based sorbents were characterized by using XRF, XRD, and N2 adsorption. The specific surface area of calcium-based sorbents was used to redefine the formula of cyclic carbonation reactivity decay. The carbonation conversion rate of three calcium-based sorbents exhibited a decreasing trend as the cycle number increased. Chicken eggshells exhibited the most significant decrease rate (over 50% compared with Cycle 1), while carbide slag and analytical reagent-grade calcium carbonate showed a flat linear decline trend. The specific surface area of th... [more]
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