Flow dynamics study of catalyst powder in catalytic cracking unit for troubleshooting

• Autorzy: Yelgaonkar V. , Agrahari G. , Vikrant D. , Prasanna R. , Pathak B. K.

Identyfikatory

DOI

10.1515/nuka-2017-0040

• Konferencja: International Conference on Applications of Radiation Science and Technology (ICARST-2017) (24-28 April 2017 ; Vienna, Austria)
• Języki publikacji: EN

Abstrakty

EN

Gamma scanning and radiotracer applications are very effective and inexpensive tools to understand and optimize the process as well as troubleshoot the various types of problems in many chemical, petrochemical industries and refineries. These techniques are non-invasive; hence, the problems can be pinpointed online, which leads to reduce the downtime, schedule the shutdown and maintenance of the plant equipment, rendering huge economic benefits. In a leading refinery of India, the catalytic cracking unit (CCU) was malfunctioning. It was suspected by the refinery engineers that the catalyst powder was being carried over to the fractionator, which could have led to erosion of the fractionator column internals resulting in their rupture, and consequentially, to the fire hazard. To understand the flow behaviour of the catalyst powder and to ensure the mechanical integrity, catalyst accumulation and choking, both radiotracer study and gamma scanning of the CCU reactor was carried out. The reactor consists of a riser, three primary cyclones and three secondary cyclones. Gamma scanning of the reactor was carried out with the help of an automatic gamma scanner using 1.8 GBq of Co-60 sealed source. Results showed that the catalyst powder was accumulated in one of the secondary cyclones and uneven density distribution was observed in another secondary cyclone. The radiotracer study was carried out using the irradiated catalyst powder as a radiotracer, which contains 0.9 GBq of Na-24. The radiotracer was injected in the reactor through the specially fabricated injection system. Radiation measurement was done using the thermally insulated and collimated NaI(Tl) scintillation detectors located at various strategic locations coupled to a multi-detector data acquisition system. The data were mathematically analysed. It was confirmed that the catalyst powder was accumulated in one of the secondary cyclones with no flow downwards. This resulted in excess powder available to travel along with hydrocarbon towards fractionator. Since the quantity of powder released through the hydrocarbon outlet of CCU was higher than the designed value, the catalyst powder was observed in various zones of the fractionator. Mathematical modelling of the radiotracer data obtained at various locations corroborated the scanning results; also, the flow pattern was obtained. Partially blocked secondary cyclone showed plug flow with recirculation; normal working cyclone had plug flow behaviour and the vortex breaker showed parallel flow.

Słowa kluczowe

EN

catalytic cracking unit; cyclones; fractionator; radiotracer; plug flow

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2017
• Tom: Vol. 62, No. 4
• Strony: 277--283
• Opis fizyczny: Bibliogr. 3 poz., rys.

Twórcy

autor

Yelgaonkar V.

• Board of Radiation & Isotope Technology, Department of Atomic Energy, Government of India, Vashi Complex, Navi Mumbai, India

autor

Agrahari G.

• Board of Radiation & Isotope Technology, Department of Atomic Energy, Government of India, Vashi Complex, Navi Mumbai, India

autor

Vikrant D.

• Board of Radiation & Isotope Technology, Department of Atomic Energy, Government of India, Vashi Complex, Navi Mumbai, India

autor

Prasanna R.

• Board of Radiation & Isotope Technology, Department of Atomic Energy, Government of India, Vashi Complex, Navi Mumbai, India

autor

Pathak B. K.

• Board of Radiation & Isotope Technology, Department of Atomic Energy, Government of India, Vashi Complex, Navi Mumbai, India

Bibliografia

• 1. Charlton, J. S. (1986). Radioisotope techniques for problem solving in industrial process plants. Glasgow: Leonard Hill.
• 2. International Atomic Energy Agency. (1990). Guidebook on radioisotope tracers in industry. Vienna: IAEA. (Technical Report Series no. 316).
• 3. Zitny, R., & Thyn, J. (1996). Programs for residence time distribution analysis, RTD software manuals for data analysis of radiotracer experiments. Vienna: International Atomic Energy Agency.

Uwagi

PL

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę (zadania 2017).