GB1582534A

GB1582534A - Vapour generating and superheating apparatus

Info

Publication number: GB1582534A
Application number: GB3127277A
Authority: GB
Original assignee: Babcock and Wilcox Ltd
Current assignee: Babcock International Ltd
Priority date: 1977-07-26
Filing date: 1977-07-26
Publication date: 1981-01-07

Description

(54) IMPROVEMENTS IN OR RELATING TO VAPOUR GENERATING AND SUPERHEATING APPARATUS (71) We, BABCOCK & WILCO LIMITED, a British Company of Cleveland House, 19, St. James's Square, London, SW1Y 4LN, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to vapour generating and superheating apparatus. Fluidized bed heaters, in which heat is produced by burning fuel interspersed in a bed of inert material which is maintained in an aerated condition, are known and this invention is concerned to provide a novel vapour generating and superheating apparatus in which a fluidized bed is used.

According to the present invention, there is provided vapour generating and superheating apparatus having a furnace chamber provided with burner means, a gas pass leading from, and extending alongside, the furnace chamber, and a fluidized bed heater lying outside and at least partly beneath the furn ceQchàmber and so disposed that combustion gases produced by the fluidized bed heater discharge into the gas pass, the floor of the furnace chamber being formed from tube lengths spaced apart with the spaces between the tubes closed by webs and serving to screen the fluidized bed heater from the heat within the furnace chamber and the outlet from the furnace chamber into the gas pass lying above the floor of the furnace chamber.

By way of example, an embodiment of the invention will now be described with reference to, and as illustrated by the accompanying drawing which shews somewhat schematically, a longitudinal section through a vapour generating and superheating apparatus.

The apparatus illustrated in the drawing includes a topifired rectangular furnace chamber 1 and, at its side, an upright rectangular gas pass 2. Economiser and other heaters are arranged in the gas pass 2. A steam-and-water drum 3 is positioned above them, and vapour generating tubes 4 extending up to the drum 3 from headers 5 from the boundary walls of the chamber 1 and gas pass 2, a single division wall 4a forming the boundary between them.

The walls 4 are formed from spaced tubes, with the spaces between the tubes closed by webs.

The headers 5 are disposed around a rectangular fluidised bed heater 10 in which crushed coal is burnt. The tubes of the single division wall 4a are connected to a header 5a extending along one side of the bed. The lower part of the wall forms a floor 4aa to the furnace chamber 1, sloping upwardly in a plane aaoss mcre than half the width of the bed of the heater 10 to a location from which they rise vertically. The floor 4aa thus forms an easily constructed screen by which the fluidized bed heater 10 is protected from the direct heat of the furnace chamber 1. For a short length above the door 4aa, adjacent tubes are displaced from each other, and the webs between them removed to provide an outlet 11 from the furnace chamber 1 into the gas pass 2.

At their lower ends, the tubes of the wall 4b of the gas pass 2 opposite the single division wall 4a slope from the header to which their lower ends are connected towards the floor 4aa, and then slope in the reverse sense to a location from which they extend upwardly, parallel to the single division wall. Thus, the floor 4aa and the lowest section of the opposite wall converge towards each other, acting as a funnel of which the outlet 12 opens into the gas pass just below the outlet 11 from the furnace chamber 1 into the gas pass 2. Thus the same gas pass 2 serves as a flue for both the furnace chamber 1 and the fluidized bed heater 10.

The fluidized bed 10 is divided across its width into two parts 14 and 15 so that the heat generated in each is separately controllable. One part contains tubes 16 in which steam is superheated prior to being expanded in a turbine and the other part contains tubes 17 in which steam is reheated between successive stages in the turbine.

In other embodiments of the invention, the fluidized bed heater may use other solid fuels than coal, or use liquid or gaseous fuel. It will also be realised that superheating may be effected partly in the gas pass 2 and partly in the bed heater 10.

WHAT WE CLAIM IS: 1. Vapour generating and superheating

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) IMPROVEMENTS IN OR RELATING TO VAPOUR GENERATING AND SUPERHEATING APPARATUS (71) We, BABCOCK & WILCO LIMITED, a British Company of Cleveland House, 19, St. James's Square, London, SW1Y 4LN, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to vapour generating and superheating apparatus. Fluidized bed heaters, in which heat is produced by burning fuel interspersed in a bed of inert material which is maintained in an aerated condition, are known and this invention is concerned to provide a novel vapour generating and superheating apparatus in which a fluidized bed is used. According to the present invention, there is provided vapour generating and superheating apparatus having a furnace chamber provided with burner means, a gas pass leading from, and extending alongside, the furnace chamber, and a fluidized bed heater lying outside and at least partly beneath the furn ceQchàmber and so disposed that combustion gases produced by the fluidized bed heater discharge into the gas pass, the floor of the furnace chamber being formed from tube lengths spaced apart with the spaces between the tubes closed by webs and serving to screen the fluidized bed heater from the heat within the furnace chamber and the outlet from the furnace chamber into the gas pass lying above the floor of the furnace chamber. By way of example, an embodiment of the invention will now be described with reference to, and as illustrated by the accompanying drawing which shews somewhat schematically, a longitudinal section through a vapour generating and superheating apparatus. The apparatus illustrated in the drawing includes a topifired rectangular furnace chamber 1 and, at its side, an upright rectangular gas pass 2. Economiser and other heaters are arranged in the gas pass 2. A steam-and-water drum 3 is positioned above them, and vapour generating tubes 4 extending up to the drum 3 from headers 5 from the boundary walls of the chamber 1 and gas pass 2, a single division wall 4a forming the boundary between them. The walls 4 are formed from spaced tubes, with the spaces between the tubes closed by webs. The headers 5 are disposed around a rectangular fluidised bed heater 10 in which crushed coal is burnt. The tubes of the single division wall 4a are connected to a header 5a extending along one side of the bed. The lower part of the wall forms a floor 4aa to the furnace chamber 1, sloping upwardly in a plane aaoss mcre than half the width of the bed of the heater 10 to a location from which they rise vertically. The floor 4aa thus forms an easily constructed screen by which the fluidized bed heater 10 is protected from the direct heat of the furnace chamber 1. For a short length above the door 4aa, adjacent tubes are displaced from each other, and the webs between them removed to provide an outlet 11 from the furnace chamber 1 into the gas pass 2. At their lower ends, the tubes of the wall 4b of the gas pass 2 opposite the single division wall 4a slope from the header to which their lower ends are connected towards the floor 4aa, and then slope in the reverse sense to a location from which they extend upwardly, parallel to the single division wall. Thus, the floor 4aa and the lowest section of the opposite wall converge towards each other, acting as a funnel of which the outlet 12 opens into the gas pass just below the outlet 11 from the furnace chamber 1 into the gas pass 2. Thus the same gas pass 2 serves as a flue for both the furnace chamber 1 and the fluidized bed heater 10. The fluidized bed 10 is divided across its width into two parts 14 and 15 so that the heat generated in each is separately controllable. One part contains tubes 16 in which steam is superheated prior to being expanded in a turbine and the other part contains tubes 17 in which steam is reheated between successive stages in the turbine. In other embodiments of the invention, the fluidized bed heater may use other solid fuels than coal, or use liquid or gaseous fuel. It will also be realised that superheating may be effected partly in the gas pass 2 and partly in the bed heater 10. WHAT WE CLAIM IS:

1. Vapour generating and superheating apparatus having a furnace chamber provided with burner means, a gas pass leading from, and extending alongside, the furnace chamber, and a fluidized bed heater lying outside and at least partly beneath the furnace chamber and so disposed that combustion gases produced by the fluidized bed heater discharge into the gas pass, the floor of the furnace chamber being formed from tube lengths spaced apart with the spaces between the tubes closed by webs and serving to screen the fluidized bed heater from the heat within the furnace chamber, and the outlet from the furnace chamber into the gas pass lying above the floor of the furnace chamber.

2. Apparatus as claimed in Claim 1 in which the floor of the furnace chamber slopes upwardly towards the gas pass.

3. Apparatus as claimed in Claim 2 in which another wall, with the floor of the furnace chamber, forms a roof to the fluidized bed heater, and the wall and floor converge towards an outlet through which combustion gases produced by the fluidized bed heater flow into the gas pass.

4. Apparatus as claimed in Claim 3, in which the wall is formed by extensions of vapour generating tubes included in the lining of the gas pass.

5. Apparatus as claimed in any of the preceding claims in which means is provided for effecting in the fluidized bed heater superheating of the vapour produced in the apparatus.

6. Apparatus as claimed in Claim 5 in which the furnace chamber and the gas pass are lined by vapour generating tubes, the vapour generating tubes discharge into a liquid-and-vapour drum, and the drum is the source of vapour that is heated in the fluidized bed heater.

7. Apparatus as claimed in either of Claims 5 and 6 in which the superheating means includes a reheater.

8. Apparatus as claimed in Claim 7 in which a part of the fluidized bed heater includes superheating means connected with a turbine in a flow path for vapour and lying upstream of the turbine, a part of the fluidized bed heater contains reheating means connected in a flow path leading from one stage to the turbine to another, and the two parts of the fluidized bed heater are separately controllable.

9. Vapour generating and superheating apparatus substantially as described with reference to, and as illustrated by, the accompanying drawing.