Title of Invention	"A PROCESS FOR BURNING SOLID PARTICULARLY IN A FLUJIDIZED BED."
Abstract	A fluidized bed combustion process comprising heating fuel uniformly and allowing the heated fuel to pass over the bed uniformly, said fuel being selected from blast furnace gas, solid fuels and steam; said fuel being used either alone or in combination at a predetermined flow rate.

Full Text

The present invention particularly relates to development of an Atmospheric Bubbling Fluidized Bed Combustion (BFBC) system to burn Blast Furnace gas without oil support alongwith solid fuels. In addition to BFG, solid fuels can also be burnt independently to generate the required stem / flue gas for further use. The present invention relates to burning coal like solid fuels in a flameless BFBC system alongwith BFG gas burner located above the fluidized bed in an efficient and environmentally clean way. Blast Furnace Gas (BFG) is a byproduct of steel plant, with high amount of Carbon Monoxide. Blast Furnace Gas has a very low calorific value and is available at very low pressure. Hence combustion of this gas in systems requires special design features. The high amount of Carbon Monoxide contained the blast furnace gas requires several safety precautions aiming at protecting personnel at site. At present this gas is being used internally in the steel plant and some furnaces. Where there is no internal requirement, the gas is being flared into the atmosphere. Fluidized bed is a system consisting of an enclosure, where solid particles remain in a suspended state. This state is achieved by passing a gas through a packed bed of solid particles. At low velocities, the pressure drop across the bed is small and the particle system will be undisturbed. But as the gas velocity is increased steadily, the pressure drop increases till a point where the pressure drop across the bed equals the weight of the bed particles per unit area. At this stage the bed particles are hi a suspended state and it is called "minimally fluidized bed". When the gas velocity is increased further, the bed becomes highly turbulent and rapid mixing of particles takes place. At this stage the bed of solids attain pseudo fluid properties. When the solid particles in a fluidized bed are preheated to the ignition temperature of fuel, the fuel fed will burn and impart heat to the whole volume of the bed. The temperature in the entire bed would be uniform. The process is called fluidized bed combustion. Fluidized bed combustion system is used for combustion of wide variety of fuels hi an environmentally acceptable manner. The invented design features maximize the utilization of BFG, while the solid fuel firing becoming supplementary. While simultaneously firing Blast Furnace Gas alongwith solid fuels in a furnace the combustion temperature in the furnace may vary according to the flow rate of each fuel and of the heat release pattern. The geometry and shape of the heat transfer surfaces are selected such that the operating parameters and the heat loading in individual sections is suitable for generating stable parameters. The heat transfer surfaces have been proportioned such that achieving stable steam parameters on firing any fuel is facilitated. The position of the BFG burner is chosen such that 1. Combustion does not require oil support; and 2. Combustion is complete above fluidized bed zone and required heat duties are achieved. The present invention provides a fluidized bed combustion process comprising heating fuel uniformly and allowing the heated fuel to pass over the bed uniformly, said fuel being selected from blast furnace gas, solid fuels and steam; said fuel being used either alone or in combination at a predetermined flow rate. In the above process waste fuel and/or solid fuel are used. Furthermore, location of the blast furnace gas burner is so selected thaqt the combustion does not require oil support and the combustion is completed above the furnace blast zone and required heat duties are achieved. In the above process of fluidized bed blast combustion the waste gases is converted into valuable fuel apart from reducing environmental pollution, such as unburnt carbon monoxide, tarry vapour and dust emission. The present invention further provides a furnace blast furnace to fire blast furnace gas without oil support, having predetermined geometry and shape of the heat transfer surfaces. In said fluidized bed furnace burners are located above the fluidized bed in an efficient and environmentally clean manner. The present invention is also directed to selection of proper operational parameters in order to maintain a wide range of temperatures in the bed and other heat transfer areas to achieve an efficient combustion and stable load. Comparing the present system with the disposal of BFG through flare stack, the system converts the waste gas to a valuable fuel apart from reducing environmental pollution such as unburnt CO, tarry vapour and dust emission, which would occur due to direct flaring, BFG firing above fluidized bed ensures combustion completion and ESP ensures fly ash dust removal. The system would have unique air regime control to facilitate improved completion of combustion of elutriated combustion particles. The present invention would also ensure safety measures for the personnel at site. WE CLAIM: 1. A fluidized bed combustion process comprising heating fuel uniformly and allowing the heated fuel to pass over the bed uniformly, said fuel being selected from blast furnace gas, solid fuels and steam; said fuel being used either alone or in combination at a predetermined flow rate. 2. A process as claimed in Claim 1 wherein said fuel is waste fuels and/or solid fuels. 3. A process as claimed in Claim 1 wherein solid fuel is a mixture of ell4 fuels with blast furnace gases. 4. A process as claimed in Claim 1 or 2 wherein the location of blast furnace gas burner is so selected that the combustion does not require oil support and the combustion is completed above the fluidized bed zone and required heat duties are achieved. 5. A process as claimed in any one of the preceding claims wherein the waste gas is converted into valuable fuel apart from reducing environmental pollution, such as unburnt carbon monoxide, tarry vapour and dust emission. 6. A fluidized bed combustion process substantially as herein described. 7. A fluidized, furnace to fire blast furnace gas without oil support, having predetermined geometry and shape of the heat transfer surfaces. 8. A fluidized^ furnace as claimed in Claim 6 wherein said blast furnace gas burners are located above the fluidized bed being an efficient and environmentally clean manner. 9. A fluidized blast furnace to fire blast furnace gas substantially as herein described.

Documents:

1139-del-2002-abstract.pdf

1139-del-2002-claims.pdf

1139-del-2002-correspondence-others.pdf

1139-del-2002-correspondence-po.pdf

1139-del-2002-description (complete).pdf

1139-del-2002-form-1.pdf

1139-del-2002-form-19.pdf

1139-del-2002-form-2.pdf

1139-del-2002-form-3.pdf

1139-del-2002-form-4.pdf

1139-del-2002-form-5.pdf

1139-del-2002-gpa.pdf