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Method for operating a fluidized bed boiler

A fluidized bed boiler and boiler technology, applied in fluidized bed combustion equipment, incinerators, combustion methods, etc., can solve problems such as anoxic streaks, fouling, and increased maintenance costs

Active Publication Date: 2021-10-15
IMPROBED AB
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These localized high temperatures cause the melting of complex ash components that adhere to the furnace walls and heat transfer surfaces downstream of the furnace, leading to fouling, corrosion problems and increased maintenance costs
Poor mixing leads, on the one hand, to oxygen-rich streaks that generate localized hot zones, and on the other hand, to oxygen-deficient streaks that generate CO emissions and, in the worst case, localized corrosion
Poor mixing is also why cyclones often act as afterburner chambers and therefore have high maintenance costs

Method used

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  • Method for operating a fluidized bed boiler
  • Method for operating a fluidized bed boiler
  • Method for operating a fluidized bed boiler

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] CFB Boiler Operation

[0063] for example, Figure 7 A typical CFB boiler is shown. Reference numerals indicate:

[0064] 1 fuel tank

[0065] 2 fuel chutes

[0066] 3 Primary combustion air blower

[0067] 4 Nozzle Bottom

[0068] 5 Primary air distributor

[0069] 6 Secondary air port

[0070] 7 fluidized bed

[0071] 8 ovens

[0072] 9 cyclone separator

[0073] 10 ring seal

[0074] 11 Immersion superheater

[0075] 12-circuit column

[0076] 13 heat exchanger

[0077] 14 Flue gas treatment device

[0078] 15 Flue gas recirculation fan

[0079] 16 flue

[0080] During normal operation, fuel is stored in the fuel tank (1 ) and can be fed to the furnace (8) through the fuel chute (2). Alternative means (not shown) for fuel supply are, for example, screw feeders and rotary valves, without excluding others. In this case, a fluidizing gas such as air is fed from below the bed to the furnace (8) via a primary air dis...

Embodiment 2

[0085] Operating a Chalmers Boiler Without a Secondary Air Supply

[0086] Chalmers 12MWth CFB boiler setup as figure 1 shown, where reference marks indicate:

[0087] 10 furnaces

[0088] 11 Fuel supply (stove)

[0089] 12 Bellows

[0090] 13 cyclone separator

[0091] 14 Convective paths

[0092] 15 Secondary Cyclone

[0093] 16 Fabric filter (textile filter)

[0094] 17 Flue gas fans

[0095] 18 particle sparger

[0096] 19 pellet cooler

[0097] 20 Gasifier

[0098] 21 particle seal 1

[0099] 22 particle seal 2

[0100] 23 Fuel supply (gasifier)

[0101] 24 Fuel Hopper (Gasifier)

[0102] 25 Hopper

[0103] 26 Fuel Hopper 1

[0104] 27 Fuel Hopper 2

[0105] 28 Fuel Hopper 3

[0106] 29 sludge pump

[0107] 30 Hopper

[0108] 31 Ash removal

[0109] 32 Measuring port

[0110] Operating the boiler with rock-type ilmenite as bed material, only primary air persisted for more than 500 minutes during th...

Embodiment 3

[0114] Figure 4 Results are shown from similar experiments in which the air to fuel ratio was dynamically changed during operation with rock-type ilmenite alone and during operation with silica sand alone as bed material in a Chalmers CFB boiler. During the experiment, both primary and secondary air were fed into the boiler. from image 3 It can be seen that when silica sand is used as the bed material, when the O in the flue gas 2 is about 3vol.% and at 2.5vol.% O 2 If CO is already present, the CO concentration is already above the limit for normal CO emissions in the boiler. This can be compared to the operation of rock-type ilmenite, where about 1.3 vol.% O in the flue gas 2 The first violation of the limit on CO emissions.

[0115] This shows that even with primary and secondary air for boiler operation using silica sand as bed material, silica sand as bed material does not allow the boiler to operate at low levels in flue gas that can be achieved with ilme...

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Abstract

The present invention relates to a method for operating a fluidized bed boiler comprising: a) setting the ratio of secondary oxygen-containing gas to primary oxygen-containing fluidizing gas to a value in the range of 0.0 to 0.8; A fluidized bed of ilmenite particles for combustion of fuel; and relates to a fluidized bed boiler.

Description

technical field [0001] The invention belongs to the technical field of fluidized bed combustion, and relates to a method of operating a fluidized bed boiler and a fluidized bed boiler. Background technique [0002] In fluidized bed combustion (FBC), fuel is suspended in a heated fluidized bed of solid particulate material, usually silica sand. In this technique, a fluidizing gas is passed through a bed of solid particles, usually silica sand, at a specific fluidization velocity. The bed material acts as a heat carrier to facilitate rapid heat transfer. At very low gas velocities, the bed remains stationary. When the velocity of the fluidizing gas is increased above the minimum fluidization velocity at which the force of the fluidizing gas balances the force of gravity acting on the particles, the solid bed material behaves in many respects like a fluid and the bed is said to be fluidized . In a bubbling fluidized bed (BFB) boiler, the fluidizing gas is passed through the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F23G5/30F23C10/18F23N3/00
CPCF23C10/18F23G5/30F23N3/00F23C2900/10001F23C2900/99008F23N2237/18F23N2237/16Y02E20/34F23C10/10F23C10/20F23N1/00
Inventor 本特-奥克·安德松弗雷德里克·林德亨里克·通曼
Owner IMPROBED AB