1 AIT Asian Institute of Technology

A study of the hydrodynamics of circulating fluidized beds

AuthorSathe, Chirag Manohar
Call NumberAIT RSPR no.ET-93-01
Subject(s)Fluidized-bed combusion

NoteA research study submitted in partial fulfillment of the requirements for the Degree of Master of Engineering
PublisherAsian Institute of Technology
AbstractThe low-grade fuels such as wood waste, sewage sludge are in abundance in nature and if efficiently utilized, can largely alleviate the present and future energy problems. Circulating fluidized bed has emerged as a new combustion technology, which can efficiently use low grade fuels, incorporating concern for the environment. In the present study, an attempt is made to study two aspects of hydrodynamics of Circulating fluidized bed, namely solid circulation rate and axial voidage distribution. The existing pilot plant was modified to understand the effect of reduced horizontal length of L-valve. Sand of 200 μm, 400 μm and 500 μm and polystyrene were used as a raw material for cold bed experiments. The experimental measurements were carried out in the range of riser air flow from 1,700 Lt/min to 2,000 Lt/min; total bed inventories from 15 to 25 kg for sand particles and 10 and 12 kg for polystyrene particles and aeration flow from 60 Lt/min to 80 Lt/min for sand particles and from 100 Lt/min to 140 Lt/min for polystyrene. Relevant correlation was developed for the present experimental work, using different dimensionless groups, for solid circulation rate. The result of correlation was in agreement with the experimental work. A general correlation was developed for the data gathered from literature as well as for the data of present study. There was a qualitative agreement for the developed general correlation. Voidage were measured along the height of the riser column. Three models for axial voidage distribution were studied in detail. A comparison was made with experimental work for the model presented by Zhang et al (1992). A poor prediction of experimental data was obtained which was not unexpected.
Year1993
TypeResearch Study Project Report (RSPR)
SchoolSchool of Environment, Resources, and Development (SERD)
DepartmentDepartment of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC))
Academic Program/FoSEnergy Technology (ET)
Chairperson(s)Bhattacharya, Sribas C.;
Examination Committee(s)Exell, R.H.B.;Prida Wibulswas;
Scholarship Donor(s)Royal Netherlands Government;
DegreeResearch Studies Project Report (M.Eng.) - Asian Institute of Technology,1993


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