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Abbasfard H.,Shahid Bahonar University of Kerman | Hashemi S.H.,Shiraz Petrochemical Complex | Rahimpour M.R.,Shiraz University | Jokar S.M.,Shiraz University | Ghader S.,Shahid Bahonar University of Kerman
Environmental Technology (United Kingdom) | Year: 2013

The nitric acid plant of a domestic petrochemical complex is designed to annually produce 56,400 metric tons (based on 100% nitric acid). In the present work, radial-flow spherical bed reactor (RFSBR) for selective catalytic reduction of nitric oxides (NOx) from the stack of this plant was modelled and compared with the conventional radial-flow reactor (CRFR). Moreover, the proficiency of a radial-flow (water or nitrogen) membrane reactor was also compared with the CRFR which was found to be inefficient at identical process conditions. In the RFSBR, the space between the two concentric spheres is filled by a catalyst. A mathematical model, including conservation of mass has been developed to investigate the performance of the configurations. The model was checked against the CRFR in a nitric acid plant located at the domestic petrochemical complex. A good agreement was observed between the modelling results and the plant data. The effects of some important parameters such as pressure and temperature on NOx conversion were analysed. Results show 14% decrease in NOx emission annually in RFSBR compared with the CRFR, which is beneficial for the prevention of NOx emission, global warming and acid rain. © 2013 Taylor & Francis. Source


Abbasfard H.,Shiraz Petrochemical Complex | Ghanbari M.,Shiraz University | Ghasemi A.,Iran University of Science and Technology | Ghahraman G.,Payame Noor University | And 2 more authors.
Applied Thermal Engineering | Year: 2014

Ammonia oxidation reactor is widely used in nitric acid plant to cause the catalytic reaction between air and ammonia to produce nitrous gases. In this work, the flow distribution inside the ammonia oxidation reactor at Shiraz Petrochemical Complex (SPC) has been simulated using Computational Fluid Dynamics (CFD) code. The CFD results showed that the flow is non-uniformly distributed inside the reactor due to improper header design of the reactor. Measuring of the temperature distribution around the skin of the reactor has been carried out using thermograph. The thermograph experiment showed a considerable temperature difference between the left and right side of the reactor. It was found that the mal-distribution of the gas flow inside the reactor can directly affect the performance of the reactor. © 2014 Elsevier Ltd. All rights reserved. Source


Abbasfard H.,Shahid Bahonar University of Kerman | Hashemi S.H.,Shiraz Petrochemical Complex | Rahimpour M.R.,Shiraz University | Jokar S.M.,Shiraz University | Ghader S.,Shahid Bahonar University of Kerman
Environmental technology | Year: 2013

The nitric acid plant of a domestic petrochemical complex is designed to annually produce 56,400 metric tons (based on 100% nitric acid). In the present work, radial-flow spherical bed reactor (RFSBR) for selective catalytic reduction of nitric oxides (NO(x)) from the stack of this plant was modelled and compared with the conventional radial-flow reactor (CRFR). Moreover, the proficiency of a radial-flow (water or nitrogen) membrane reactor was also compared with the CRFR which was found to be inefficient at identical process conditions. In the RFSBR, the space between the two concentric spheres is filled by a catalyst. A mathematical model, including conservation of mass has been developed to investigate the performance of the configurations. The model was checked against the CRFR in a nitric acid plant located at the domestic petrochemical complex. A good agreement was observed between the modelling results and the plant data. The effects of some important parameters such as pressure and temperature on NO(x) conversion were analysed. Results show 14% decrease in NO(x) emission annually in RFSBR compared with the CRFR, which is beneficial for the prevention of NO(x) emission, global warming and acid rain. Source


Zareie-kordshouli F.,Shiraz Petrochemical Complex | Darvishi P.,Yasouj University | Lashani-zadehgan A.,Yasouj University | Ejlali M.,Shiraz Petrochemical Complex
Engineering Failure Analysis | Year: 2016

In spite of improvements in reformer tube metallurgy and manufacture, outlet pigtail tubes are now seen as a critical and weak link component of primary steam reformer in ammonia plants and often require replacement before the reformer tubes. The present work has been focused to find out causes of damaging 12 outlet pigtails of primary steam reformer in the ammonia plant of Shiraz Petrochemical Complex (SPC) after 7-8.5 years of operation from metallurgical and process point of view. A process evaluation based on operating variables and a detailed metallurgical investigation based on microstructural assessment, chemical and reduced thickness analysis, micro hardness measurements, metallography and tensile properties of pigtail samples has been performed. The obtained findings demonstrated that the failure of outlet pigtails was attributed to over-design operating temperatures. Under operation at high temperature, the pigtails undergo the advance stage of irreversible creep and failed before their designing life span. © 2015 Elsevier Inc. Source

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