Optimal Energy Recovery from Ammonia Synthesis in a Solar Thermal Power Plant

Siddiq, S.; Khushnood, Shahab; Koreshi, Zafar Ullah; Shah, Musannif; Qureshi, Arshad Hussain

doi:10.1007/s13369-013-0552-y

Cited by 10 publications

(5 citation statements)

References 8 publications

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“…The inlet temperatures at the optimum conditions were higher for the first three beds and lower for the fourth bed when compared with the industrial inlet temperatures. Increase in optimum inlet temperatures were also reported in the works of Saddiq et al [2]. The outlet temperature at the end of the fourth catalyst bed also decreased from 742.87 K to 716.60 K indicating more efficient heat utilization resulting in a reduction in temperature.…”

Section: Effect Of Optimum Inlet Temperatures On Percent Conversionsupporting

confidence: 71%

“…Optimization involves minimizing or maximizing an objective function; in most optimization problems, the objective function could be an economic return or term based on some parameters of the system, minimizing a cost function or maximizing a profit function; Optimizing the efficiency of the system by minimizing or maximizing parameters that indicates performance of the system viz: minimize specific energy consumption [1], optimize maximum energy output [2], minimum catalyst volume obtained to satisfy the production capacity at specified operating conditions [3], maximum mass flow rate of production using a generic algorithm at optimal conditions of inlet temperature, total feed flow rate and operating pressure [4], optimize reactor performance by varying its quench flows: Temperature and flow rate [5], obtain optimum reactor length [6] [7] that gives the maximum profit with objective function being: a function of the process parameters (heating value of product and feed gas) and reactor capital cost [8].…”

Section: Introductionmentioning

confidence: 99%

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Optimization of an Ammonia Synthesis Converter

Akpa¹,

Raphael²

2014

WJET

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A scheme that optimizes the converter of an ammonia synthesis plant to determine optimal inlet temperatures of the catalyst beds has been developed. The optimizer maximizes an objective function-The fractional conversion of nitrogen on the four catalyst beds of the converter subject to variation of the inlet temperature to each catalyst bed. An iterative procedure was used to update the initial values of inlet temperature thus ensuring accurate results and quick convergence. Converter model results obtained with optimized operating conditions showed significant increase in fractional conversion of 42.38% (from 0.1949 to 0.2586), increased rate of reaction evident in a 13.18% (0.5317 to 0.4616) and 23.84% (0.1946 to 0.1482) reduction in reactants (hydrogen and nitrogen) concentration respectively and a 56.48% increase (from 0.1181 to 0.1838) in ammonia concentration at the end of the fourth catalyst bed compared to results obtained with industrial operating conditions.

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Section: Effect Of Optimum Inlet Temperatures On Percent Conversionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Optimization of an Ammonia Synthesis Converter

Akpa¹,

Raphael²

2014

WJET

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“…However, the energy intensive process now accounts to 90% of world's NH3 manufacturing (Bartels & Pate, 2008;Yilmaz & Ozturk, 2022). Global NH3 plant capacity in the 1950s were a few hundred tons/day, which grows to an annual volume of 130 MMT in 2000, 133 MMT in 2008, 205 MMT in 2010, 235 MMT in 2019and 239 MMT in 2020(Anantharaman et al, 2012Ghavam et al, 2021;Gosnell, 2005;Morgan, 2013;Siddiq et al, 2011). With an annual increment ranging from 1.67-2.3% in the last few years, its estimated value is put at 100 billion USD with 226 MMT average annual production between 2010-2020 (Brightling, 2018;Macfarlane et al, 2020;Smith et al, 2020;Zhang et al, 2019).…”

Section: Literature Reviewmentioning

confidence: 99%

Process Modeling and Simulation of Ammonia Production from Natural Gas: Control and Response Analysis

Abubakar

Royani

Gezerman

et al. 2023

JTIE

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Optimal production of ammonia (NH3) using natural gas is necessary in order to make it available for wide range of applications including the manufacture of fertilizers, fuel for transportation and during synthesis of some chemicals. Achieving this would require strategic implementation of a control scheme to simulated ammonia production, capable of ensuring adequate realization of production targets. The work involves ASPEN Plus modeling, simulation, sensitivity analysis and control of NH3 production process. Steam/carbon ratio, conversion of CH4, removal of carbon dioxide (CO2) and carbon monoxide (CO), hydrogen/nitrogen ratio and heat exchanger and separator temperatures were identified as requiring control in units any of these specifically impacts. As a result, approximately 176 tons of NH3 was realized daily based on the simulation results and can be scaled-up using a calculated factor equivalent to 1.1375 to 200 tons/day capacity, in this design. Sensitivity analysis resulting in control of certain unit parameters is effective in ensuring process safety, maximum yield of important end-products and reduction in the cost of operation

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“…A solar thermochemical power plant has been analyzed in Reference where the heat recovery from the synthesis reactor has been maximized. Optimal energy recovery from ammonia synthesis in a solar thermal power plant has been studied in Reference . The synthesis reactor of a Kellog‐type ammonia plant has been optimized by using genetic algorithms in Reference .…”

Section: Introductionmentioning

confidence: 99%

Optimal design and operation of ammonia decomposition reactors

Badescu

2020

Int J Energy Res

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The design and steady-state operation of a packed bed reactor with tubular geometry is optimized. Direct optimal control methods are used. Two objective functions are considered: (i) minimization of the ammonia mass fraction at reactor outlet and (ii) minimization of the heat flux necessary to reach a predefined value of the ammonia mass fraction at reactor outlet. The optimization process is performed by using different controls, that is, the space distributions of (1) tube wall temperature T w , (2) circular tube diameter D tube , and (3) diameter d p of the catalyst spherical particles. Results for the first objective function are as follows. The optimal distribution of T w along the reactor consists of a constant temperature or a U-shaped space temperature distribution, respectively, depending on the allowed range of variation of T w . The optimal space distribution of D tube (or, in other words, the shape of the reactor tube) depends of T w . For smaller values of T w the tube is narrower at inlet and larger at outlet while the reverse situation happens for larger values of T w . For lower T w values, particles with smaller diameter d p are placed at reactor inlet while when higher values of T w are considered, particles with larger d p are placed at reactor inlet. When both D tube and d p are used as controls, the optimization results are generally different from the results obtained from one-control optimization. Results for the second objective function are as follows. The optimal space distribution of T w starts with high values at reactor inlet. Next, the temperature decreases abruptly towards a minimum (which is lower for longer tubes). Finally, the temperature increases smoothly towards a maximum near the reactor outlet. The required heat flux slightly decreases by increasing the tube length. The optimal D tube ranges between its maximum allowed value (at reactor inlet) and its minimum allowed value (at reactor outlet). The best performance is obtained for catalyst particles of the smallest allowed diameter. K E Y W O R D Sammonia decomposition reactor, minimum heat consumption, optimal design, optimal operation

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Optimal Energy Recovery from Ammonia Synthesis in a Solar Thermal Power Plant

Cited by 10 publications

References 8 publications

Optimization of an Ammonia Synthesis Converter

Optimization of an Ammonia Synthesis Converter

Process Modeling and Simulation of Ammonia Production from Natural Gas: Control and Response Analysis

Optimal design and operation of ammonia decomposition reactors

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