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Goswami S, Kshirsagar VS, Aswini V, Sharma VK, Samantray JS, Gupta R, Pawar PM, Pant HJ. Evaluation of mixing performance and validation of CFD simulations in baffled anaerobic digesters using radiotracer technique. Appl Radiat Isot 2023; 192:110570. [PMID: 36462300 DOI: 10.1016/j.apradiso.2022.110570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 11/13/2022] [Accepted: 11/18/2022] [Indexed: 11/27/2022]
Abstract
The anaerobic digesters find usage in treating the huge amount of waste such as trash, garbage, human waste and animal waste. The sustained performance of an anaerobic digester depends on the flow pattern and mixing behaviour in the digester. A cylindrical digester tank with vertical baffles can provide flow behaviour approaching that of a plug flow reactor. However, the presence of dead zones and recirculating regions cause non-ideal flow in the digester. In this work, the mixing behaviour in two scaled-down models of baffled digester tanks is characterized by measurement of residence time distribution (RTD) using a radioactive tracer. While the first design has three vertical baffles, the second design include horizontal static flaps on the baffles. The flow behaviour in the digester is also simulated using computational fluid dynamics (CFD) and RTD is obtained computationally. The comparison of RTD curves obtained from CFD simulations with those obtained from radiotracer experiments show good agreement between them. There appear to be only minor difference in the flow behaviour and the RTD curves in the two digester designs. Using the RTD curve data, two commonly used RTD models, tank-in-series and dispersion models, have been fitted and both models are able to predict the RTD in the digester qualitatively.
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Affiliation(s)
- Sunil Goswami
- Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - V S Kshirsagar
- Department of Civil Engineering, SVERI's College of Engineering, Pandharpur, Solapur, 413304, India
| | - V Aswini
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - V K Sharma
- Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - J S Samantray
- Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Raghvendra Gupta
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - P M Pawar
- Department of Civil Engineering, SVERI's College of Engineering, Pandharpur, Solapur, 413304, India
| | - H J Pant
- Isotope and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
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