Executive Summary : | Objective: Petcoke is the residue produced from refining heavy oils and has a higher green-house emissions. Low-sulphur petcoke is widely used in metal manufacturing, while high-sulphur petcoke is burned to generate heat. Lime stone is generally used during petcoke combustion to capture SOx. Central Pollution Control Board has very stringent norms on industrial emissions. Blending of coal with petcoke in thermal power plants and other metallurgical industries is possible if the emission level are controlled as per the permissible norms. Fluidized bed reactor (FBR) is a popular technology for combustion of pet coke and coal. The scale-up of FBR is reportedly a difficult process due to number of parameters involved and sensitivity of fluidization state to these parameters. Summary: The high level of SOx emission from the combustion of petcoke make its industrial use formidable due to stringent pollution norms laid down by Central Pollution Control Board (CPCB) and other environmental agencies. Mixing of petcoke with coal is observed to reduce its Sulphur-dioxide emission and control the calorific values. The gaseous SOx emission can be captured in solid form by the use of lime stone. The process can be achieved in a Fluidized Bed Reactors (FBR) which have numerous advantages ranging from uniform and controlled temperature, excellent mixing, high solid-gas contact surface area etc. The proposed work has two components (a) the studies on the proportions of mixing of the petcoke, coal and limestone for the effective capture of the sulphur dioxide. (b) the optimization of operating and design parameters of the fluidized bed reactors for their most efficient performance. The FBR gains different fluidization states based on fluidization velocity such as fixed bed, minimum fluidization, smooth fluidization, bubbling fluidization, slugging, turbulent fluidization etc. Optimization for best performance in this regard is essential. CFD-DEM coupled simulations of Eulerian-Eulerian, Eulerian-Lagrangian (resolved/unresolved) are effective techniques to study the effect of various operating and design parameters. Circulating Fluidized Boilers (CFB) shall be optimized in the proposed work. The system is to be utilized for minimal emissions of Sulphur dioxide under the norms laid by pollution control board, and make petcoke a feasible fuel in the metallurgical and power industries. |