Modeling and optimization of an ammonia reactor using a penalty-like method

Carvalho, Esdras P.; Borges, Carolina; Andrade, Doherty; Yuan, Jinying; Ravagnani, Mauro A.S.S.

doi:10.1016/j.amc.2014.03.099

Cited by 17 publications

(8 citation statements)

References 6 publications

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“…Then, the reactants and product are inserted into a heat exchanger and condenser for separation. After ammonia separation and liquidation, the reactants are prepared to return to the reactor by passing a compressor and the heat exchanger. , Catalysts such as nickel, iron oxide, ruthenium, and molybdenum are used in this process . In most cases, iron-promoted catalysts are used.…”

Section: Process Descriptionmentioning

confidence: 99%

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

2023

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This investigation analyzes the simultaneous production of hydrogen and ammonia as carbon-free energy carriers and methyl formate (MF) as a widely used chemical intermediate in a multifunctional membrane reactor (MFMR). The MFMR, based on Le Chatelier’s principle, has the advantage of changing the thermodynamic equilibrium by direct thermal coupling between ammonia synthesis and MF production and shifting the chemical equilibrium with the use of the Pd–Ag membrane. In the innovative configuration, the nitrogen conversion rate has been increased from 38.2 to 41.2% and the methanol conversion from 16.3 to 99.1%. Other benefits of the MFMR include providing the required energy for an endothermic reaction and eliminating a furnace and cooler in methanol dehydrogenation and ammonia synthesis reactors. Furthermore, it has been demonstrated that if the ammonia synthesis reaction is positioned at the center side of the MFMR, the nitrogen and methanol conversion are, respectively, 1.32 and 7.34% higher than when the reaction is located at the outer side of the MFMR. Likewise, the effect of operational process parameters such as inlet flow rates, inlet temperatures, and membrane thickness on the performance of each reaction has been studied. Utilizing multiobjective optimization (MOO), it has been observed that ammonia and MF production yields can reach 20.3 and 24.1%, respectively.

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Section: Process Descriptionmentioning

confidence: 99%

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

2023

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“…A genetic algorithm (GA) in combination with the NAG (numerical algorithms group) numeric subroutine library present in MATLAB was used by those authors, and good optimal values for the process variables and the objective function were found. Later, better optimal values with higher convergence velocities were achieved by Babu and Angira [13] with the use of differential evolution (DE), by Yusup et al [14] using the shooting methods implemented in MATLAB, by Akpa and Raphael [15] for different catalytic beds using the program converter simulator, by Ksasy et al [16] with a real-coded genetic algorithm, and by Carvalho et al [1] using the extreme barrier function combined with direct-search methods.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Convergence to extremes is guaranteed by this method. [1] However, the high convergence time when compared to other search methods makes it susceptible to substitution or combination with other methods. [39]…”

Section: Golden Section Searchmentioning

confidence: 99%

“…Moreover, ammonia compounds have applicability in the manufacture of explosives, fibres, plastics, chemicals, polymers, and cooling fluids. [1] Also, ammonia compounds can be used in alkaline pretreatments based on ammonia, such as hydrogen peroxide presoaking before ammonia fibre expansion (H-AFEX). [2] These pre-treatments modify porous structure, resulting in increased enzyme accessible surface area and facilitating the subsequent enzymatic hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

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Maximization of the profit and reactant conversion considering partial pressures in an ammonia synthesis reactor using a derivative‐free method

2021

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In the present paper, an optimization model is proposed for the ammonia synthesis reactor. The reversible exothermic reaction has nitrogen and hydrogen as reactants, at high temperatures, and high pressures with iron catalyst. Two different single-objective optimization problems were considered, the maximization of the economic return and the maximization of the nitrogen conversion. The reaction rate model was defined as a function of partial pressures of the components. The problem was coded and solved in MATLAB using a derivative-free method after reformulating a constrained optimization problem into an unconstrained one, by penalizing the infeasibilities of the constraints in the objective functions (barrier function). The main contributions of this paper are the combination of direct-search methods in solving the optimization problem, the evaluation of the maximum ammonia production and the temperature profile. The optimal values found were better than the ones published in the literature.

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“…The heat exchanger’s exit gas enters the condenser where the ammonia will be liquidized and then separated from the unreacted hydrogen and nitrogen mixture. Moreover, the unreacted mixture transfers to the reactor again immediately after heating up by the heat exchanger. − …”

Section: Process Descriptionmentioning

confidence: 99%

Analysis of the Combined Ammonia Production and Cyclohexane Dehydrogenation by a Novel Bifunctional Reactor

2019

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In the current work, a novel process including a multitubular thermally coupled reactor for the simultaneous production of benzene and ammonia is proposed. The ammonia synthesis reaction inside the internal tubes provides the cyclohexane dehydrogenation reaction’s heat demand in the external tube. Moreover, this novel configuration eliminates the required interstage cooler in the conventional ammonia synthesis plant, leading to a remarkable reduction in operational costs. Furthermore, the cyclohexane dehydrogenation process has been employed to supply all of the ammonia synthesis hydrogen demand; therefore, the production, transportation, and storage cost of hydrogen have been greatly reduced. Besides, the danger of hydrogen gas transportation has been avoided. As another advantage of the proposed configuration, cyclohexane conversion in the thermally coupled reactor has been increased from 0.842 to 0.887 compared to a conventional cyclohexane dehydrogenation reactor. Finally, the performance of the proposed reactor has been studied under various inlet temperatures and molar flow rates.

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Modeling and optimization of an ammonia reactor using a penalty-like method

Cited by 17 publications

References 6 publications

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

Improvement in Ammonia, Hydrogen, and Methyl Formate Synthesis Process by Employing Multiobjective Optimization of a Novel Multifunctional Membrane Reactor

Maximization of the profit and reactant conversion considering partial pressures in an ammonia synthesis reactor using a derivative‐free method

Analysis of the Combined Ammonia Production and Cyclohexane Dehydrogenation by a Novel Bifunctional Reactor

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