The effect of H2:N2ratio on the NH3synthesis rate and on process economics over the Co3Mo3N catalyst

2021-02-01
Hargreaves, Justin S.J.
Aslan, Melis
Üner, Deniz
In this study, the process economics of ammonia synthesis over Co3Mo3N was investigated by searching for an optimum feed stoichiometry. From ammonia synthesis rate measurements at atmospheric pressure and 400 °C over Co3Mo3N, it was found that the rate was independent of H2: N2 stoichiometry for stoichiometries above 0.5: 1. For H2: N2 stoichiometries below 0.5: 1, there was a linear dependency of ammonia synthesis rate on the H2: N2 stoichiometry. Static measurements of hydrogen adsorption isotherms at 25, 50, and 100 °C revealed that the adsorbed amounts of strongly bound hydrogen over the Co3Mo3N surface were saturated at around 100 Torr hydrogen pressure. This pressure corresponds to the partial pressure of hydrogen when the H2: N2 stoichiometry is around 0.5: 1, confirming the role of strongly bound hydrogen in ammonia synthesis. These results were used to modify an existing kinetic expression to be used in a conceptual design, based on a late mixing strategy for the hydrogen stream. This conceptual design and its economic analysis revealed that using low hydrogen stoichiometries can cut the investment and operating costs by a factor of 2. This journal is
Faraday Discussions

Suggestions

The preparation and characterization of nano-sized Pt-Pd/C catalysts and comparison of their superior catalytic activities for methanol and ethanol oxidation
Ozturk, Zafer; Sen, Fatih; Sen, Selda; Gökağaç Arslan, Gülsün (2012-12-01)
In this study, two groups of carbon supported PtPd samples with different percentages of metals were prepared to examine the effects of Pd and stabilizing agents on the catalytic activity towards methanol and ethanol oxidation reactions. As a stabilizing agent, 1-hexanethiol and 1,1-dimethyl hexanethiol were used for group "a" and "b" catalysts, respectively. Cyclic voltammetry, chronoamperometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, and X-ra...
Optimization and Comparison of High-Pressure-Assisted Extraction of Phenolic Compounds from Olive Pomace
Okur, İlhami; Öztop, Halil Mecit; Alpas, Hami (2022-12-16)
In this study, it was aimed to find the optimum condition for extraction of phenolic compounds from olive pomace by using high-pressure-assisted extraction (HPAE). In this method, different pressure parameters (300-500 MPa), times (5-15 min), and ethanol concentrations (50-90% v/v) were used. According to Box-Behnken design, 15 experimental runs were performed to find the optimum condition of total phenolic and oleuropein contents. Also, the optimum HPAE condition was compared with that of classical solvent...
The impact of methionine, tryptophan and proline on methane (95%)-propane (5%) hydrate formation
Longinos, Sotirios Nik; Longinou, Dimitra-Dionisia; Parlaktuna, Mahmut; Toktarbay, Zhexenbek (2021-10-01)
This study examines the impact of three amino acids such as proline, methionine and tryptophan on methane (95%)-propane (5%) hydrate formation with the use of different impellers. The concentration of amino acids was 1 wt% at 24.5 bar and 2 degrees C. Based on experimental outcomes proline behaves as inhibitor and methionine and tryptophan perform as promoters. RT experiments both formed more quickly gas hydrates and indicated higher values in rate of hydrate formation compared to PBTU and PBTD experiments ...
The effect of aromatic diboronic acid on characteristics of polybenzoxazine based on phenol and 4-aminomethylbenzoate
İPEK, HALİL; Hacaloğlu, Jale (2018-11-23)
In this study, a polybenzoxazine, (PPab) based on phenol and 4-aminomethyl benzoate and its composites containing various amounts of 1,4-benzene diboronic acid, (BDBA) were synthesized by stepwise curing. It has been determined that both thermal stability and char yield were increased as the amount of BDBA incorporated was increased. The improvements in thermal characteristics were associated with condensation reactions of B-OH of BDBA and not only with hydroxyl groups of polybenzoxazine but also ester grou...
The Effects of Co-Mo/CaCO3 Catalyst's Calcination Temperature and Co/Mo Weight Ratio on Carbon Nanotube Production
Hocaoglu, Caner; Sezgi, Naime Aslı (2015-01-01)
Carbon nanotubes (CNTs) were synthesized in the temperature range of 500-700 degrees C over cobalt (Co)- and molybdenum (Mo)impregnated CaCO3 catalysts using acetylene gas. The effects of Co-Mo/CaCO3 catalyst's calcination temperature and Co/Mo weight ratio on the carbon deposition rate were investigated. The synthesized CNTs were multiwalled nanotubes with variable outer diameters. They exhibited Type II isotherm, and their surface areas were in the range of 24.8-89.9m(2)/g. It was concluded that the Co/Mo...
Citation Formats
J. S. J. Hargreaves, M. Aslan, and D. Üner, “The effect of H2:N2ratio on the NH3synthesis rate and on process economics over the Co3Mo3N catalyst,” Faraday Discussions, pp. 475–488, 2021, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85107390973&origin=inward.