Analysis of integrated system for ammonia synthesis and methyl formate production in the thermally coupled reactor

Nikzad, Amin; Iranshahi, Davood

doi:10.1016/j.cep.2021.108418

Cited by 9 publications

(2 citation statements)

References 38 publications

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“…Penkuhn et al 12 explored different configurations of the ammonia production process using exergy technology, determining that the indirect cooling configuration exhibited lower energy requirements and higher ammonia purity. Nikzad et al 13 investigated the simultaneous production of ammonia and methyl formate in a thermal coupling reactor, demonstrating that the methyl formate production process could fulfill 20.57% of the hydrogen requirement for ammonia synthesis. Mirvakili et al 14 utilized computational fluid dynamics (CFD) to simulate a two-dimensional axis-radial ammonia synthesis reactor, achieving a 14% increase in ammonia yield by reducing the inlet temperature by 40 K. However, previous studies primarily focused on one-dimensional or two-dimensional models of green ammonia reactors, often overlooking the three-dimensional flow dynamics and geometric complexities of the reactor.…”

Section: Introductionmentioning

confidence: 99%

How to Achieve Flexible Green Ammonia Production: Insights via Three-Dimensional Computational Fluid Dynamics Simulation

Zhang,

Li,

Zhou

et al. 2024

Ind. Eng. Chem. Res.

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The green ammonia synthesis process involves producing ammonia using hydrogen obtained from electrolyzing water with renewable energy sources, thereby contributing to carbon emission reduction and promoting sustainable development. However, in large-scale commercial operations, there exists a contradiction between the volatility of renewable energy and the stability required in chemical production processes: the fluctuation of the power supply and feedstocks constantly brings new changes to the heat and mass transfer of the fluid in the reactor, which will pose a severe challenge to the flexibility of reactor operation. In this study, we utilized a combination of reaction kinetics and computational fluid dynamics (CFD) to conduct three-dimensional modeling of the green ammonia reactor with validation against industrial data. The proposed novel approach facilitated the prediction of spatial flow field distribution within the reactor and assessment of varying load impacts on green ammonia yield and production index. The results indicate minimal deviation in processing parameters from baseline operating conditions under varying loads, yet a notable reduction in green ammonia yield occurs with decreased production loads, nearly reducing by 50%. Through the sensitivity analysis, the optimal operation scheme under different production loads is proposed. For example, at 30% load, the optimal operating pressure and hydrogen/nitrogen ratio are 14 MPa and 3.1, which are quite different from the baseline operating conditions. However, such process flexibility comes at the expense of catalyst and energy utilization, decreasing exergy efficiency by approximately 30% and potentially leading to operational anomalies such as gas dead spaces, low-temperature zones, and backflow, underscoring the trade-offs inherent in enhancing process flexibility. Nonetheless, the application potential of the green ammonia flexible synthesis process remains promising. Our proposed three-dimensional reactor simulation offers theoretical underpinnings for ensuring stability and optimal operation regulation in green ammonia production.

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Section: Introductionmentioning

confidence: 99%

How to Achieve Flexible Green Ammonia Production: Insights via Three-Dimensional Computational Fluid Dynamics Simulation

Zhang,

Li,

Zhou

et al. 2024

Ind. Eng. Chem. Res.

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“…For example, the reactor systems may be too expensive to operate, too maintenance-hungry, and too complex. , A critical issue in such stacked reactor systems is how the throughput rate varies with the number of channels. In these systems, the residence time of the process stream is relatively lower, , and the rate of heat supply to the endothermic reaction zone is relatively higher. , The construction of these stacked reactor systems is essentially similar, , and thus, the linear scale-out assumption is often made that the output level varies linearly with the channel number. , However, this assumption limits the applicability of the models to practical situations, since the abrupt extinction of the process reaction may occur due to the effect of exterior heat loss.…”

Section: Introductionmentioning

confidence: 99%

Effects of Stack Structure and Heat Loss on the Stability and Efficiency of Steam-Methanol Reforming Microreactors for Hydrogen Production

Chen

Miao

2023

Ind. Eng. Chem. Res.

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The linear scale-out approximation ignores the influence of exterior heat loss and thus cannot address extinction issues. The present study is focused primarily upon the roles of stack structure and heat loss in the stability and efficiency of microreactors for hydrogen production by steam-methanol reforming. Computer simulations are performed to model the complex physicochemical processes in a variety of different heat loss situations. The effects of channel number, wall thermal conductivity, and surface-area-to-volume ratio are investigated to assess the importance of stack structure and heat loss in microreactor design. The results indicate that the total heat loss becomes increasingly significant for designing reactors with small stacks of channels. About half of heat released is lost if a global-type extinction occurs. The critical heat loss coefficient depends heavily upon the number of channels. The design with a large stack of channels more closely beneficially improves heat utilization and reduces heat loss. There is a significant linear relationship between energy efficiency and heat loss coefficient. Significant heat loss may cause extinction in edge channels while still permitting very high conversion in center channels. The wall thermal conductivity is of vital importance to ensure stability operation. Higher wall thermal conductivity provides stability benefits, but walls with very low thermal conductivity can be employed to reduce heat loss by sacrificing the thermal coupling capability.

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Modeling and optimization of ammonia reactor

Bagheri,

Hashemipour

et al. 2024

Progresses in Ammonia: Science, Technology and Membranes

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Analysis of integrated system for ammonia synthesis and methyl formate production in the thermally coupled reactor

Cited by 9 publications

References 38 publications

How to Achieve Flexible Green Ammonia Production: Insights via Three-Dimensional Computational Fluid Dynamics Simulation

How to Achieve Flexible Green Ammonia Production: Insights via Three-Dimensional Computational Fluid Dynamics Simulation

Effects of Stack Structure and Heat Loss on the Stability and Efficiency of Steam-Methanol Reforming Microreactors for Hydrogen Production

Modeling and optimization of ammonia reactor

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