Flue Gas Research Articles

Development of a Membrane Process in CAPE-OPEN to CAPE-OPEN (COCO) Simulator for Carbon Dioxide Separation

Commercial process simulation software like HYSYS® and UniSIM® are available but they require a license to operate. CAPE-OPEN to CAPE-OPEN (COCO) is a free process simulation software that includes many unit operations. In terms of material and energy balance, COCO gives very close results compared to commercial software. Gas-separation membrane can be developed manually in HYSYS® and UniSIM® using a component splitter but this unit is not available in COCO. In this work, a membrane module was built in COCO with the use of the open-source numerical computational application (Scilab). The membrane unit was developed by writing material and energy balance equations in Scilab. The equations were solved numerically by changing the permeate-cut values. The code was then integrated into COCO using the Scilab plugin. The built code was tested with an industrial membrane unit for carbon dioxide separation from flue gas. Results show that the module gives an acceptable error of 4.5% when performing material and energy balance compared to real data.

Computational screening of metal–organic frameworks for separation of CO2 and N2 from wet flue gas

Computational screening of metal–organic frameworks for separation of CO2 and N2 from wet flue gas

Evaluation of the applicability of carbon-based materials for arsenic removal from flue gases

Arsenic is an highly toxic element which may be released into the atmosphere during the combustion of solid fuels. This paper verifies the possibility of using char from tires CT and lignite dust LD as materials for the adsorption of gaseous forms of As. The source of the gaseous forms of arsenic was coal combustion under laboratory conditions. Adsorption tests included both different sorbent bed temperatures (120–180°C) and various flue gas compositions (resulting from the combustion of bituminous and lignite coals). It was shown that sorption temperature did not affect the arsenic removal efficiency for both analysed sorbents. The average As removal efficiency for tire char and lignite dust was 88 and 92%, respectively. The composition of the burned coal, and thus the composition of the flue gas, significantly influences the efficiency of Asgas adsorption. While for LD the level of As removal was still high (more the 90%), the sorption of Asgas by tire char from the flue gas when lignite was burned was less effective (the efficiency was below 80%). It was additionally indicated via a leachability test that "used" CT could be safely disposed of while LD would require appropriate management. Based on the comparison of the performance of CT and LD with commercial AC activated carbon and the differences in their market price, it can be concluded that the studied alternative sorbents are competitive with AC.

Oxidation Study and Mechanism Analysis of Desulfurization Ash in Dense-Phase Tower

Dense-phase-tower desulfurization technology is an emerging semi-dry flue-gas desulfurization ash process, i.e., the flue gas is allowed to enter the desulfurization tower from the bottom up and, at the same time, is sprayed with a desulfurizing agent that undergoes an acid–base reaction with the flue gas in the ascent process. The calcium sulfite and calcium sulfate produced by the reaction and the part of the desulfurization agent that is not involved in the reaction will enter the subsequent dust removal system, and what is retained is the by-product desulfurization ash. This desulfurization ash contains a large amount of calcium sulfite, which leads to its unstable nature; it is easily oxidized and expands in volume, and, if used in the field of building materials, it will lead to cracking and other problems, so it is difficult to effectively use it. In order to solve this problem, XRF, XRD, and iodometric and other analytical methods were used to determine the specific composition of desulfurization ash, and the muffle furnace and vertical tube furnace were used to study the thermal oxidative modification of calcium sulfite in desulfurization ash, to investigate the effects of the oxygen content, reaction temperature, medium flow rate, and chloride content on the oxidation of calcium sulfite, and to analyze the thermodynamics in the high-temperature oxidation reaction. The results showed that the oxidation rate of calcium sulfite increased with higher reaction temperatures. Increased oxygen content promoted the oxidation rate, particularly at low oxygen levels. The oxidation rate of calcium sulfite correlated positively with the medium flow rate until a rate of 75 mL·min− was reached. At a reaction temperature of 420 °C and a gas flow rate of 85 mL·min−1, the oxidation conversion efficiency exceeded 89%. Chloride content significantly reduced the oxidation rate of calcium sulfite, although this inhibition weakened at temperatures above 500 °C. Kinetic analysis suggested that the oxidation reaction of calcium sulfite predominantly occurred below 500 °C. These findings have both theoretical and practical implications for the thermal oxidation treatment and disposal of desulfurization ash.

A Study of the Influence of Cement Addition and Humidity on the Mechanical Strength and Microstructure of Flue Gas Desulfurization Gypsum-Cement Plasters.

Over the last 20 years, flue gas desulfurization gypsum (FGD gypsum) has become a valuable and widely used substitute for a natural raw material to produce plasters, mortars, and many other construction products. The essential advantages of FGD gypsum include its high purity and stability, which allow for better technical parameters compared to natural gypsum, and, until recently, its low price and easy availability. This FGD gypsum is obtained in the process of desulfurization of flue gases and waste gases in power plants, thermal power plants, refineries, etc., using fossil fuels such as coal or oil. The gradual reduction in energy production from fossil raw materials implemented by European Union countries until its complete cessation in 2049 in favor of renewable energy sources significantly affects the availability of synthetic gypsum, and forces producers of mortars and other construction products to look for new solutions. The gypsum content in commonly used light plaster mortars is usually from 50 to 60% by mass. This work presents the results of tests on mortars wherein the authors reduced the amount of gypsum to 30%, and, to meet the strength requirements specified in the EN 13279-1:2008 standard, added Portland cement in the amount of 6-12% by mass. Such a significant reduction in the content of synthetic gypsum will reduce this raw material's consumption, thus extending its availability and developing other solutions. The study presented the test results on strength, density, porosity, pore size distribution, and changes in the microstructure of mortars during up to 180 days of maturation in conditions of increased relative humidity. The results show that decreased porosity and increased mechanical strength occur due to the densification of the microstructure caused by the formation of hydration products, such as C-S-H, ettringite, and thaumasite.

Experimental combustion characteristics and NOx emissions for a 600‐MWe utility boiler after the retrofitted: Effects of load variation

AbstractTo enhance the rapid switching ability of the boiler load and reduce NOx emissions, a new combustion system was implemented in a 600‐MWe wall‐fired boiler with swirl burners. This system included two levels of overfire air (OFA) and low NOx combustion technology. Industrial tests were conducted at 300‐, 450‐, and 600‐MWe loads before and after the retrofitted. These tests included measuring flue gas and furnace temperatures with thermocouples and analyzing local gas concentrations using a gas analyzer. The research results indicate that under conditions where the OFA ratio exceeds 30%, the burner exhibits good ignition performance at different loads. At the 600‐MWe load, the nitrogen oxides (NOx) emissions were reduced by 55% compared to before the retrofit. After the retrofit, the flame center inside the furnace of different loads was located at the height of 33.36 m, the first and second‐stage cooling water quantities were slightly higher, the reheat cooling water quantity was greatly reduced after the retrofit, and contributes to the boiler's safe operation. Under different load conditions after the retrofit, the gas temperature near the sidewall was below 850°C, and the O2 concentration near the sidewall was above 5%, effectively suppressing sidewall high‐temperature corrosion and slagging.

Design and Analysis of the Exhaust Muffler for Two-Wheeler Vehicle

The muffler is an essential part of every type of car. On two-wheelers, however, it disperses flue gases throughout the atmosphere and reduces engine noise to a bearable level. It is occasionally called an exhaust muffler or a muffler. A silencer's main function is to block off noise produced when flue gas rushes past it quickly. Furthermore, the exhaust gases ought to be released into the atmosphere. The primary focus of this work is on two-wheeled vehicle exhaust mufflers. The current exhaust silencer design is subjected to CFD and fluid structure interaction analysis with engine-specific boundary conditions. The specifications will guide the creation of the muffler's design. ANSYS, a finite element analysis tool is used to measure and verify exhaust gas temperatures, velocities, and back pressure. Furthermore, a modal analysis is conducted to figure out how a geometric adaptation affects the fundamental frequency of the system. The actual testing consists of fabricating a customized exhaust silencer and evaluating it for noise and back pressure on a two-wheeler engine test rig.

Efficient Capture and Electroreduction of Dilute CO2 into Highly Pure and Concentrated Formic Acid Aqueous Solution.

High-purity CO2 rather than dilute CO2 (15 vol %, CO2/N2/O2 = 15:80:5, v/v/v) similar to the flue gas is currently used as the feedstock for the electroreduction of CO2, and the liquid products are usually mixed up with the cathode electrolyte, resulting in high product separation costs. In this work, we showed that a microporous conductive Bi-based metal-organic framework (Bi-HHTP, HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) can not only efficiently capture CO2 from the dilute CO2 under high humidity but also catalyze the electroreduction of the adsorbed CO2 into formic acid with a high current density of 80 mA cm-2 and a Faradaic efficiency of 90% at a very low cell voltage of 2.6 V. Importantly, the performance in a dilute CO2 atmosphere was close to that under a high-purity CO2 atmosphere. This is the first catalyst that can maintain exceptional eCO2RR performance in the presence of both O2 and N2. Moreover, by using dilute CO2 as the feedstock, a 1 cm-2 working electrode coating with Bi-HHTP can continuously produce a 200 mM formic acid aqueous solution with a relative purity of 100% for at least 30 h in a membrane electrode assembly (MEA) electrolyzer. The product does not contain electrolytes, and such a highly concentrated and pure formic acid aqueous solution can be directly used as an electrolyte for formic acid fuel cells. Comprehensive studies revealed that such a high performance might be ascribed to the CO2 capture ability of the micropores on Bi-HHTP and the lower Gibbs free energy of formation of the key intermediate *OCHO on the open Bi sites.

Low-temperature deNOx performance and mechanism: a novel FeVO4/CeO2 catalyst for iron ore sintering flue gas

Low-temperature deNOx performance and mechanism: a novel FeVO4/CeO2 catalyst for iron ore sintering flue gas

Indigo as a Low‐Cost Redox‐Active Sorbent for Electrochemically Mediated Carbon Capture

AbstractClimate change has driven the need for carbon capture to mitigate anthropogenic greenhouse gas emissions, yet current thermochemical methods are hampered by high energy intensities. Electrochemically mediated carbon capture (EMCC) utilizing redox‐active carbon dioxide (CO2) carriers is an attractive alternative for carbon capture. Here, an economical vat dye compound, indigo, is presented, which can reversibly capture and release CO2 upon electrochemical reduction and oxidation, respectively. Electrode and electrolyte engineering strategies are utilized to improve the reversibility and stability of indigo for EMCC. A bench‐scale prototypical fixed‐bed carbon capture device is constructed to demonstrate indigo's EMCC performance under various practically relevant conditions, such as simulated flue gas and extremely dilute sources pertinent to direct air capture. A hybrid sorbent electrode‐gas diffusion layer approach is revealed to alleviate CO2 mass transport limitations, achieving ≈80% CO2 capacity utilization under a 15% CO2 feed stream. Furthermore, a reactive‐diffusive mass transport model is developed to illustrate engineering approaches that can be universally applied to optimize fixed‐bed EMCC systems. This work advances the potential for a class of low‐cost sorbents for EMCC while underscoring the importance of molecular, electrolyte, materials, and device engineering strategies to enable high‐performance carbon capture.

Scalable Jet‐Based Fabrication of PEI‐Hydrogel Particles for CO2 Capture

The capture, regeneration, and conversion of CO2 from ambient air and flue gas streams are critical aspects of mitigating global warming. Solid sorbents for CO2 absorption are very promising as they have high mass transfer areas without energy input and reduce emissions and minimize corrosion as compared to liquid sorbents. However, precisely tunable solid CO2 sorbents are difficult to produce. Here, we demonstrate the high‐throughput production of hydrogel‐based CO2‐absorbing particles via liquid jetting. By wrapping a liquid jet consisting of an aqueous solution of cross‐linkable branched polyethylenimine (PEI) with a layer of suspension containing hydrophobic silica nanoparticles, monodisperse droplets with a silica nanoparticle coating layer was formed in the air. A stable Pickering emulsion containing PEI droplets was obtained after these ejected droplets were collected in a heated oil bath. The droplets turn into mm‐sized particles after thermal curing in the bath. The diameter, PEI content, and silica content of the particles were systematically varied, and their CO2 absorption was measured as a function of time. Steam regeneration of the particles enabled cyclic testing, revealing a CO2 absorption capacity of 6.5 ± 0.5 mol kg−1 solid PEI in pure CO2 environments and 0.7 ± 0.3 mol kg−1 solid PEI for direct air capture. Several thousands of particles were produced per second at a rate of around 0.5 kg per hour, with a single nozzle. This process can be further scaled by parallelization. The complete toolbox for the design, fabrication, testing, and regeneration of functional hydrogel particles provides a powerful route toward novel solid sorbents for regenerative CO2 capture.

Computational fluid dynamics numerical simulation of flue gas emission from stack and tower integration system of coal-fired power plant

ABSTRACT The method of Computational Fluid Dynamics (CFD) simulation has been extensively employed in the stack and tower integration technology (STIT) research; however, a significant number of studies overlooked the impact of thermal buoyancy on the external flow field of cooling tower. In light of this, an improved approach is proposed in this study. A model of a cooling tower and its surrounding flow field was established, and its reliability was confirmed too. Based on our model, the performance of three enhancement strategies under various crosswind speeds and ambient temperatures was simulated. The results indicate that all three enhancement strategies can effectively simulate the effects of thermal buoyancy. In the simulations, the elevation of the flue gases increased from 306 m to either 426 m or 476 m. In the present study, ambient conditions characterized by crosswind speeds below 4 m/s and temperatures below 297.15 K were deemed suitable for the dispersion of stack and tower integration (STI) flue gases. A power function distribution was identified between crosswind speed and the mean height of the plume, while a linear relationship was observed between ambient temperature and the mean height of the plume.

Boosted regeneration of coked SAPO-34 catalyst in MTO fluidized bed reactor by diluted air at elevated temperatures

SAPO-34 zeolite as an excellent catalyst for methanol-to-olefins (MTO) reaction suffers rapid deactivation by prevalent coking. Herein, regeneration of coked-SAPO-34 in a fluidized-bed reactor was successfully intensified by altering temperature (550–650 °C) and oxygen content (7–21 vol.%). Fresh, used, and regenerated catalysts were characterized by different methods to understand the correlation between regeneration conditions, coke content, and catalyst performance. The minor residual coke over the regenerated catalyst comprised active hydrocarbon pool intermediates (like naphthalene, benzaldehyde, phenol, and derivatives), which increased by decreasing regeneration temperature and promoted the selectivity to light olefins at earlier reaction times. The restored microporosity and lifetime of regenerated catalyst were superior by increasing temperature. However, higher attrition at 650 °C, as confirmed by SEM images, caused a partial weight loss of the catalyst and a slight decline in relative crystallinity, hence 600 °C was preferred with additional advantage of less energy consumption. Meanwhile, introducing lower oxygen not only moderated the coke oxidation rate but also enhanced the recovery of beneficial catalytic features for the MTO conversion. Consequently, considering an excellent regeneration as well as lower emission of CO2 detected in the flue gas, diluted air containing 14 vol.% O2 at 600 °C was suggested as the most promising method.

Effect of CO2 Gasification on Nitrogen Oxide Emission in Oxy-Fuel Combustion.

Due to the cumulative effect of the recycled flue gas in oxy-fuel combustion, the reduction of NO has become the focus of research in which the role of CO2 gasification has a nonnegligible effect. In this article, the heterogeneous gasification mechanisms of CO2 on coal char during oxy-fuel combustion were studied by density functional theory and transition-state theory. The zigzag char model and char(N) model were selected to investigate the CO2 adsorption and gratification reactions at the molecular level. By comparison, the CO2 gasification reaction is preferred to occur on the zigzag char model with a reduction in the energy barrier and an increase in the reaction rate. When considering char nitrogen conversion, the gasification reaction is more prone to releasing NO first, leading to the contraction of the aromatic ring and the generation of CO at high temperatures. Therefore, the study further highlights the promoting role of CO2 gasification on the homogeneous and heterogeneous reduction of NO, which is mainly reflected in the reduction effect of CO. Moreover, it also accelerates the consumption of coal char and NO formation, which is favorable for the reduction reactions to a certain extent.

Accounting of carbon sequestration and tradeoff under various climatic scenarios in alternative agricultural system: a comprehensive framework toward carbon neutrality

IntroductionThe increase in atmospheric CO2 concentration, which mainly is attributed to fossil-fuel combustion and deforestation, is often suggested as one of the prime causative factors toward accelerated global warming. This commends for sequestration of atmospheric carbon under terrestrial systems to partially offset fossil-fuel emissions. Concerning the same, agricultural sector presents an extensive opportunity, especially for countries such as India where over 55% of the population is engaged in the agriculture sector.MethodsSequestering atmospheric carbon in agriculture requires the adoption of climate-resilient alternative agriculture practices without compromising food security. The deliberated study highlights the options of alteration in current conventional farming practices and its economic evaluation for sequestrating carbon under two Climate Change (CC) scenarios, viz., RCP 4.5 and 8.5, over three temporal scales, i.e., 2020, 2030, and 2050. Considering the current land-use pattern and existing growth rate in land-use shifting, three land-use policies, namely, Business as Usual (BaU), Optimistic, and Pessimistic scenario, integrated with CC scenarios were contemplated. Six possible futuristic scenarios were generated for the assessment of carbon sequestration and its valuation following the Integrated Valuation of Ecosystem Services and Tradeoff (InVEST) model.ResultsThe results suggested that across the studied region adopting an optimistic policy over BaU and pessimistic scenario, carbon can sequestrate an additional 0.64 to 1.46 Mt. (2.35 to 5.36 million ton CO2e) having an economic value of 193.4 to 504.8 million USD.ResultsMoreover, the outcomes of the study are advocated for the policy of carbon credit in the agriculture sector, which shall contribute toward meeting various nationally determined contributions (NDCs) and sustainable development goals (SDGs) as well.

Energy optimization of a non-aqueous solvent CO2 absorption system with pressure swing regeneration

This study focuses on optimizing the energy requirement in the post-combustion CO2 capture system using pressure swing regeneration through a model-based design (MBD). The simulation results highlight the significant impact of CO2 recovery, inlet gas and liquid flow rate, and CO2 concentration in the flue gas on the overall energy demand of the system. Moreover, an investigation into the de-sublimation chamber was undertaken, revealing a relationship between dry ice formation and the heat transfer between the LNG stream and CO2 in the heat exchanger. The parametric analysis study reveals that the sensible heat of the lean solvent is significantly influenced by the CO2 concentration in the liquid, consequently affecting the overall system energy. According to the results, the utilization of cold energy from LNG could save 80 % of the total energy requirement. The optimization results found the best working condition, which consumes energy of 0.190 GJ/ton CO2, 31 % lower than the basic scenario.

Effect of amine groups on the NO adsorptive separation selectivity of FeAl‐BDC‐NH2 MOFs

In this work, the effect of amine groups of MOFs materials on the NO separation selectivity under the simulated mixed atmosphere had been first investigated by comparison of NO adsorptive separation selectivity of Fe‐BDC, Al‐BDC, FeAl‐BDC and Fe‐BDC‐NH2, Al‐BDC‐NH2, FeAl‐BDC‐NH2 synthesized by solvothermal method. The experimental results showed that the adsorption capacity of NO by Fe‐BDC‐NH2, Al‐BDC‐NH2, and FeAl‐BDC‐NH2 was significantly larger than Fe‐BDC, Al‐BDC, and FeAl‐BDC at 100 kPa, which indicated ‐NH2 promotes the adsorption of NO and was much higher than the adsorption capacity of CO2, O2, and N2 under the same conditions. The NO adsorption capacity and selectivity of bimetallic FeAl‐BDC‐NH2 were significantly better than that of monometallic Fe‐BDC‐NH2 and Al‐BDC‐NH2. The NO adsorption capacity of FeAl‐BDC‐NH2 can reach 216.42 cc g−1, which exceeded lots of MOFs materials reported, and the adsorption selectivities of NO/CO2 and NO/O2 by IAST under the simulated mixed atmosphere reached 1,350 and 15,962. It also proved that the material adsorbed NO because NO forms NONOate with ‐NH2 by the in situ IR and enthalpy calculation of adsorption, and the adsorption mechanism of NO was preliminarily investigated. The results provided a new direction for the application of adsorption and separation of NO in flue gas.

Feasibility Analysis of Resource Application of Dry Flue Gas Desulfurization Ash in Asphalt Pavement Materials

To verify the feasibility of applying dry flue gas desulfurization ash (DFGDA) to asphalt pavement materials, the asphalt mastic (filler and asphalt composition) prepared by adding different proportions of DFGDA and LSP (limestone powder) into 70# matrix asphalt was studied experimentally. The asphalt mastics were subjected to the penetration test, the softening point test, and the ductility test. Moreover, the rheological properties of asphalt mastic were evaluated with dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests. An interaction ability index C-value based on the Palierne model was proposed to evaluate the interaction ability between DFGDA and asphalt. The influence of DFGDA asphalt on the interaction ability of matrix asphalt was observed and evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that with the increasing proportion of DFGDA, the penetration of asphalt mastic gradually decreased, the softening point increased, and the ductility slightly decreased. At the same temperature, the dynamic shear modulus G* of the asphalt mortar significantly increased with increasing DFGDA content. The incorporation of DFGDA negatively affected the low-temperature plastic deformation resistance of asphalt, but the impact was weakened with the growing DFGDA amount and the powder mastic ratio. The combination mode of DFGDA and matrix asphalt depends on the physical blending, and their interaction ability mainly depends on the miscibility between DFGDA and matrix asphalt. In conclusion, DFGDA can be utilized as a novel filler in asphalt pavement materials.

Effect of Mineral Admixtures on Physical, Mechanical, and Microstructural Properties of Flue Gas Desulfurization Gypsum-Based Self-Leveling Mortar.

The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), retarder, and defoamer were used to prepare GSLM. The impact of mineral admixtures (steel slag (SS), silica fume (SF), and fly ash (FA)) on the physical, mechanical, and microstructural properties of GSLM was examined through hydration heat, X-ray diffractometry (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) analyses. The GSLM benchmark mix ratio was determined as follows: 94% of desulfurization building gypsum, 6% of cement, 0.638% each of water reducer and retarder, 0.085% each of HPMC and defoamer (calculated additive ratio relative to gypsum), and 0.54 water-to-cement ratio. Although the initial fluidity decreased in the GSLM slurry with silica fume, there was minimal change in 30 min fluidity. Notably, at an SS content of 16%, the GSLM exhibited optimal flexural strength (6.6 MPa) and compressive strength (20.4 MPa). Hydration heat, XRD, and Raman analyses revealed that a small portion of SS actively participated in the hydration reaction, while the remaining SS served as a filler.

Techno-economic analysis of blue ammonia synthesis using cryogenic CO2 capture Process-A Danish case investigation

Ammonia is a vital chemical with numerous applications. Currently, the primary methods for generating the necessary reactants for ammonia production involve steam methane reforming (SMR) and cryogenic air separation unit (CASU), while the Haber-Bosch process converts these reactants into ammonia. However, the SMR process releases substantial amounts of CO2, making it imperative to employ an efficient and cost-effective CO2 capture technology to mitigate emissions. This investigation focuses on evaluating the cryogenic CO2 capture (CCC) process for blue ammonia production and provides a thorough economic analysis, estimating both the initial investment costs and operational expenses involved in producing blue ammonia. The results indicated that the CCC process can capture 90% of the CO2 content in the flue gas emitted by the SMR, incurring an energy penalty of 0.724 MJe/kgCO2 while capturing CO2 in the liquid phase with purities exceeding 99.9%. In this case, the estimated CO2 capture costs would be 18.05, 45.1, and 16.65 USD/ton in 2021, 2022, and 2023, respectively. This represents a 40% reduction compared to the CO2 capture costs associated with conventional amine-based technology. The results of this study indicate that the annual electricity costs for ammonia production increase by 38.5% and 64.2% when employing the CCC and amine-based processes, respectively. This investigation employed an isothermal reactor for ammonia synthesis, using the heat from the exothermic reaction in a water ammonia absorption refrigeration cycle (ARC) to condense and purify ammonia. The results show that the ARC system can effectively condense ammonia at −6 °C, producing a liquid ammonia stream with 99.3% purity. This leads to a 95% reduction in power consumption compared to a vapor compression refrigeration cycle (VCRC). Consequently, this method has the potential to decrease the annual operational costs for ammonia production by 2.92%, 2.69%, and 3.13% in 2021, 2022, and 2023, respectively. This study indicated that the hydrogen production unit incurs the highest initial investment costs, as well as operating costs, in the blue ammonia production process, followed by CASU and the Haber-Bosch process.