Claims:1. A rotary air pre-heater for a thermal power plant comprises of; rotor (fig 1), rotor drive bracket, diaphragms, heat transfer elements, pedestals, rotor housing, axial seal plate (8), gas side panel, primary side panel, secondary air side panel, framework of steel structure; the diameter of the said rotor (fig 1) is increased by changing the thickness of the said axial seal plate (8) and height of the said rotor (fig 1) is increased by changing the height of the said heat transfer element (2).

2. The process as claimed in claim 1, wherein the rotor (fig 1) diameter is increased up to 500mm by changing the thickness of axial seal plate (8).

3. The process as claimed in claim 1, wherein the rotor (fig 1) height is increased up to 1 meter by changing the height of the heat transfer element (2).

4. The process as claimed in claim 1, 2 and 3, wherein the said modifications rest within the framework of steel structure.

5. The process as claimed in claim 1, 2and 3, wherein it can be used with all type of rotor (fig 1) pre heater constructions.

6. The process as claimed in above claims, wherein the modified dimensions are applicable to all types of air preheater configurations.
, Description:[0013]The present invention deals with the design of air pre heater (2) in accordance to the quality of fuel inputs in different power plants. In the present invention to increase performance of the air pre heater (2) and to increase the overall efficiency of power plant the air pre-heater is optimised.

[0014]The air Preheater is to be optimised in size to provide increased thermal performance and reduced pressure drop within the available cubical volume. In the optimization the diameter of the air pre-heater is increased upto 500 mm with existing support structure layout thereby providing a greater heating surface area. In thermodynamic principle greater the heating surface area, higher the heat transfer capabilities. According to the said principle the waste heat after useful work is extracted in the air pre heater (2) arrangement. The air inlet to the furnace extracts the excess heat, which is used to enhance the combustion process.

[0015]In addition to the above said advancement the height of the rotary air pre heater (2) is increased up to 1 meter with the existing support structure layout so as to provide better boiler efficiency. Height of the rotary pre-heater is increased by changing the height of heating element within the framework of steel structure and other external equipment.

[0016]Based on this invention, the available air pre-heater size at site will be studied and suitably the volume required for the purpose of holding heat transfer elements will be increased retaining same dimensions of the foot and supporting beams.
[0017]With reference to FIG1, the Isometric view of conventional rotary air preheater is shown with numerical identifiers to represent the main parts and sub-assemblies. Ref.07 represents the upside stream of primary air (7), Ref.06 represents the upside stream of secondary air and Ref.05 represents the downside stream of flue gas. The rotary air preheater has rotor (fig 1) Ref.02 at the centre housed in housing constitutes of main pedestal Ref.10, side pedestal Ref.03, primary pedestal and panels.
[0018]The rotor (fig 1) radially extends from post with separating plates called diaphragms. Further plates are placed like chords at different places away from centre forming compartments between diaphragms. Basketed Heat transfer elements are placed in these compartments. Ref.12 represents the cold end centre section which supports the rotor (fig 1).Ref.11 is hot centre section and guides the rotor (fig 1).Ref.01 & 04 represents the duct at hot and cold end respectively. The total air preheater is supported by supporting structure Ref.09.
[0019]Fig.2 shows the top plan of existing size of Air Preheater. Ref.08 is axial seal plate (8) fixed at main pedestals and primary pedestal which are close to the rotor (fig 1). Ref.13 is primary pedestal supported by reference Ref.09.Ref.14 is Rotor (fig 1) drive bracket on which drive mechanism is fixed to drive Air preheater rotor (fig 1).”D1” represents the existing rotor (fig 1) diameter.
[0020]Fig.3 shows the top plan of modified housing and rotor (fig 1) assembly. Ref 08-M axial seal plate (8) is replaced to suit modified rotor (fig 1) Ref.02-M.Entire rotor (fig 1) housing which includes pedestals Ref.10 M, Rotor (fig 1) Drive Bracket Ref.14-M, Gas Side Panel Ref.15-M, Air Side Panel Ref.16-M, Secondary Air Side Panel Ref.17-M & Gas side Panel with Basket removal Door Ref.18-M are modified to accommodate modified rotor (fig 1) assembly Ref.02-M.”D2” represents the modified rotor (fig 1) diameter.
[0021]Fig.4 is a typical cut section elevation showing existing rotor (fig 1) assembly Ref.02 with Main pedestal Ref.10 of rotor (fig 1) housing. Existing axial seal plate (8) Ref.08 mounted on Main pedestal Ref.10 is also shown Placement and position of different heating elements are shown in the rotor (fig 1) Ref.02. ”D1” represents the existing rotor (fig 1) diameter.
[0022]Fig.5 is a typical cut section elevation showing modified rotor (fig 1) assembly Ref.02-M.Main pedestal Ref.10-M of rotor (fig 1) housing, Existing axial seal plate (8) Ref.08-M mounted on Main pedestal Ref.10-M are all modified suitably to accommodate the modified rotor (fig 1). Placement and position of different heating elements are shown in the rotor (fig 1) Ref.02-M. ”D2” represents the modified rotor (fig 1) diameter.