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Ammonia-soda process, which produce soda ash, emits flue gas containing a large amount of CO 2 and SO x. The wastewater discharged from the ammonia-soda process contains cations, such as Na+ and Ca2+, which can be recovered and reacted with a CO 2 and SO x. In this study, we designed a CO 2 and SO x utilization process for the sustainable production of sodium carbonate using wastewater recovery system, extracting Na+ and Ca2+. The proposed process involved the following steps: (1) metal-ion separation, which produces NaOH and Ca(OH) 2 ; (2) capture and utilization of SO x using Ca(OH) 2 ; and (3) capture and utilization of CO 2 using NaOH and Ca(OH) 2 , respectively. The economic feasibility of the proposed process was verified by comparing its total annualized cost (TAC) with those of conventional processes. Approximately 99% of SO x was captured to produce high-purity desulfurized gypsum, and 99% of CO 2 was captured to be transformed into CaCO 3. To confirm the CO 2 reduction of the process, the carbon dioxide equivalent (CO 2 e) was calculated by evaluating the amount of greenhouse gases. The CO 2 e decreased to 71.4% compared with that of the conventional process. The TAC of the proposed process decreased by 10.67% and 19.63% compared with that of the ammonia-soda and Hou processes, respectively. Thus, this study proposes an industrially potential process design for sustainable sodium carbonate production by utilizing CO 2 and SO x with wastewater recycling, without additional reactants, making it more economically viable. • The method uses metal-ion separation to convert wastewater to useful products. • It captures and utilizes ∼99% of SOx from Solvay wastewater. • It captures 99% of CO 2 from CaCO 3 production. • Total annualized cost of the process can be decreased by 11%. • It does not require raw materials as it uses wastewater. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive, multidisciplinary approach to high-throughput screening (HTS) of metal–organic frameworks (MOFs) for efficient ammonia-based green hydrogen production. Previous HTS methods, relying on molecular simulations, often estimate adsorption uptakes under constant conditions, leading to inadequate evaluation of MOFs for practical applications where competitive adsorption and varying operating conditions are critical. To address this limitation, we propose a multidisciplinary HTS method employing an efficient computational algorithm that minimizes the number of molecular simulations while generating isotherm models across a wide pressure range. Our algorithm strategically selects simulations for further analysis based on initial results. Using this innovative approach, we screened 12,020 MOFs. Furthermore, as the next step of the multidisciplinary approach, we performed pressure swing adsorption (PSA) process simulations to assess MOFs' potential for purifying green hydrogen derived from decomposed ammonia, which can be produced by sustainable energy sources and transported intercontinentally. The top-performing MOFs were evaluated for stability based on literature data and MOFSimplify, a neural network model estimating thermal stability. By considering adsorption process operation and MOF stability, the proposed HTS methodology identified 10 high-performing materials, with RAVXIX ranking as the top adsorbent. This comprehensive evaluation advances the search for efficient MOFs in green hydrogen production, contributing to the development of a more sustainable hydrogen-based economy. • A multidisciplinary high-throughput screening method using an novel algorithm was proposed. • The proposed HTS considers molecular and process simulations and structural stability. • This study presents MOFs best suited for green NH 3 -based H 2 separation. • Best-performing MOFs based on PSA simulation and stability were found for green NH 3 -based H 2 separation. [ABSTRACT FROM AUTHOR]

Because green ammonia is an emerging transportation medium for carbon-free hydrogen, technologies for efficient and cost-effective separation and purification of green hydrogen have attracted significant attention in recent years. Among the various options for hydrogen separation, pressure swing adsorption (PSA) has the highest technology readiness level, but the optimal adsorbent for this application is still under investigation. This study evaluates the viability of covalent organic framework (COF) adsorbents for ammonia-based green hydrogen separation processes. The feasibility of the adsorbents was estimated based on the economic analysis of the entire green hydrogen production process with a newly proposed multiscale high-throughput screening (HTS) approach. This approach addresses an existing knowledge gap, where the molecular- and process-scale viewpoints are not fully considered together during adsorbent evaluation. The proposed HTS approach incorporates a new algorithm for simulations with reduced computational cost and a procedure for estimating the economic viability of the adsorbents. The results show that among 648 COFs in a COF database, MPCOF was the most efficient for ammonia-based green H 2 separation with a H 2 recovery of 72% and levelized cost of USD 8.30/kg H 2. This result was obtained with only 31% of the computational cost required by an existing HTS approach. • Novel high-throughput screening (HTS) method is proposed based on multiscale simulation. • The proposed HTS spans from molecular- to process- scale including economic analysis. • Optimal adsorbent for H 2 production from green NH 3 is identified with the proposed HTS. • New isotherm fitting algorithm in HTS offers higher accuracy and computational efficiency. [ABSTRACT FROM AUTHOR]

• Integration between CO 2 mineralization and desalination. • Integrated process is designed and simulated. • Economic viability and CO 2 reduction potential are examined. • Using wind-based electricity significantly improves the process performance. This study presents a novel process integration scheme between CO 2 mineralization and brackish water reverse osmosis (BWRO). The integration is based on the reciprocal nature of these two processes: While CO 2 mineralization needs metal ions such as Na+ to convert CO 2 into mineral carbonates like sodium bicarbonate, BWRO is designed to reject such ions to produce fresh water. Thus, there is a potential synergy that can be gained through their integration. To examine the feasibility of such process integration, techno-economic analysis (TEA) and CO 2 life cycle assessment (LCA) are conducted for various possible configurations of the integrated process. A key requirement for TEA and CO 2 LCA is the availability of mass and energy balance data. Therefore, the process is simulated with the commercial simulation software tool of Aspen Plus combined MATLAB. Another requirement is the selection of appropriate evaluation scenarios. Based on a market analysis, the proposed process is assumed to be installed either in the US or in the China to replace a respective conventional benchmark process. Also, two sources of electricity (coal and wind onshore) are considered in the evaluation in order to investigate the sensitivity of the process performance on the type of electricity used. As a result of the analysis, the CO 2 avoidance cost of the designed process is calculated to be 132˜245$/metric ton of CO 2 with wind-based electricity. Given other advantages of the mineralization over the geological storage, the presented process integration between CO 2 mineralization and BWRO deserves further investigation as a means to produce useful chemicals and fresh water while curbing CO 2 emission. [ABSTRACT FROM AUTHOR]

As adsorption is being considered as a candidate technology for CO 2 capture, a variety of new adsorbents are being developed, such as those based on novel materials like metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs). New adsorbents are typically evaluated based on measures like working capacity and selectivity , which can be easily calculated using isotherm data. However, these indicators do not directly consider the adsorbents' performance in their end application, which typically is the pressure swing adsorption (PSA) process. Motivated by this, this work presents alternative indicators of adsorbent material’s performance evaluated specifically in the context of the PSA process. In order to keep their use simple and general, the proposed indicators are formulated assuming an idealized PSA process. Analytical expressions are derived wherever possible. In a case study involving several real adsorbents, the indicator values are compared to the results from the dynamic simulation of the PSA process and to the conventional working capacity and selectivity values. [ABSTRACT FROM AUTHOR]

Shadowgraphy-based image processing studied in the literature on multiphase processes has led to meaningful advances in mass transfer enhancement via interfacial area enlargement. However, the industrial applications of shadowgraphy have been limited due to the requirement of an additional light source at specific locations. To overcome this limitation, in this study, a new bubble size measurement technique in low-light conditions is proposed. The technique uses reflected LED image on the bubble surface to estimate the bubble size in low-light conditions and includes a newly derived measurement correlation model, which was validated with lab-scale experimental data. Furthermore, the proposed model was applied to industrial-scale bubble systems for hydrogen fluoride (HF) removal. Using the bubble properties identified through analysis, the overall mass transfer coefficient (OMTC) was determined as an indicator of HF mass transfer enhancement. The optimal conditions for HF mass transfer were determined by identifying the system with the highest OMTC. By manipulating the pressure difference and flow rate, OMTC was increased by ∼78% of the base case. [Display omitted] [ABSTRACT FROM AUTHOR]

We developed a computer-aided evaluation software system for CO 2 capture adsorbents, named General Adsorbent Library and Evaluation (GALE). This software, freely available for downloads, provides two practical functions: an extensive sorbent library with isotherm parameters for more than 2000 sorbents and a computationally efficient function to evaluation their performance for user in a pressure swing adsorption (PSA) process. The new sorbent library provides isotherm parameters, which were calculated through molecular simulations using the previously available structure libraries. Based on these parameters in the software, performances of user-selected adsorbents can be evaluated and ranked in terms of the CO 2 capture efficiency in an ideal PSA process. The evaluation function is designed to address diverse situations such as varying feed conditions and target purities. Some innovative strategies regarding the use of purity upper bound and candidate pool reduction concepts are suggested to lower the computational load. [ABSTRACT FROM AUTHOR]

[Display omitted] At public bus stops, NO X pollutants discharged by regularly stopping buses quickly accumulate, exposing waiting passengers to high levels of air pollutants, which creates a threat to public health. The environmental protection agency (EPA) presents air quality standards for NO X , a significant pollutant that causes lung diseases such as asthma when exposed to the human body. To handle this problem, air purification systems are installed inside bus stops in many public places. However, it is challenging to maintain a low concentration of NO X inside public bus stops due to the persistent inflow of bus exhaust gas. Therefore, it is crucial to design an optimal location for an air purification system to meet air environment standards for respiratory areas. This study proposed a computational fluid dynamics (CFD)-based optimal installation strategy for an air purification system to minimize NO X exposure inside a public bus stop. The CFD model was developed to numerically analyze NO 2 exposure with the actual design value for a public bus stop in Ulsan, South Korea. The local NO 2 concentration was evaluated in the human breathing zone. The case study was performed according to the locations of the inlet and outlet of the air purification system. A transient CFD simulation was performed to analyze the effect of the air purification system on pollutants generated from the stationary bus by time flow in various cases. NO 2 concentration and exposure reduction effectiveness (ERE) were analyzed and compared for each case in the breathing zone. In the optimal case, the ERE of NO 2 was confirmed to be 35.9 %, and the NO 2 concentration according to the air quality standards of EPA could be maintained at 0.1 ppm or less. The theoretical framework proposed in this study can be generalized to design air purification systems for general external facilities. [ABSTRACT FROM AUTHOR]

[Display omitted] • On-site hydrogen refueling stations require efficient catalysts/reactors. • Intrinsic kinetics of Ru catalysts were estimated using a parametric estimation. • New multistage (two- and three-stage) reactor designs were proposed. • Multistage reactors showed less temperature drop (better reactor stability). • Three-stage reactor can improve hydrogen production and conversion. In recent years, interest in the development of a hydrogen economy has increased, and the steam methane reforming (SMR) reaction, which yields so-called "gray" hydrogen, is expected to play a key role in hydrogen refueling stations (HRSs) in the interim before "green" hydrogen process is developed. For this purpose, compact and economical designs for small- to medium-scale SMR processes for HRSs are required. Herein, we investigated the intrinsic kinetics of a Ru-based catalyst using catalyst experiments and parametric estimation. In addition, reactor modelling was performed using a kinetic model with a special focus on multistage reactor configurations. The proposed reactor design showed an increase in the reactor energy supplied rate from 6.98 to 7.55 kW compared to the base case (single-stage reactor), and the conversion increased from 86.2% to 91.2%. Further, the drastic temperature drop owing to the strongly endothermic nature of the SMR reaction was reduced, and, thus, reactor stability was improved. The proposed novel design of a multistage reactor using a Ru-based catalyst will advance the development of the hydrogen economy. [ABSTRACT FROM AUTHOR]