DD214913B1 - DEVICE FOR REDUCING MECHANICAL WEAR OF BURN CARBON STEAM-FIRED STEAM GENERATORS - Google Patents

Description

For this 1 page drawing

Field of application of the invention

The invention is particularly applicable to steam generators, which are driven with ballastreichen, especially ash or SiO ₂ -rich lignite dust and have at least a second train and an overhead Querzug.

Characteristic of the known technical solutions

Sand and ash particles carried along by flue gases within a steam generator are the cause of excessively high mechanical signs of wear on internals of the steam generator.

The signs of wear are particularly pronounced where mainly by changing the direction of the return gas guide the entrained sand and ash particles can not follow the flue gas flow freely, come out as a veil on the outer flow layers and so enriched to areas downstream heat exchanger or heating surfaces,

such. B. economizer or air preheater meet.

There are known measures, according to which baffles or wear plates are provided to reduce wear on wear-prone areas in the second train. They are justified insofar as the abrasive particles carried in the flue gas are kept within limits and other wear-prone areas can be protected against premature failure due to self-wear. But if the ash and / or the sand parts in the flue gas exceed critical values, as is often the case with the coals currently used and still to be used in the future, the solids flows occurring as fogs are no longer with internals and the like. to dominate alone.

By the DDR -120534 (F 23 J, 3/02) a method for reducing the deposition of solid, liquid and volatilized Mineralbestan'dteile on the Nachschaltheizflächen is known to steam generators, after which the deposition of these components in a Querzug deliberately brought about before the Nachschaltheizflächen becomes. For this purpose, the flue gases are accelerated in a defined long, narrowing in the direction of the flue gas flow channel and directed by means of water or steam jets against one or more baffles, which can precipitate agglomerates and accumulate in a funnel. Apart from the fact that for directly entrained in flue gases sands and other mineral components with strong schleißender effect to their maintenance no agglomeration is required, the known measure is bound to the presence of a defined channel within the Querzuges and thus difficult to implement in existing steam generators.

Another variant for the maintenance of dust fractions larger grain within a steam generator according to SU-PS 420316 (B 01 D, 45/08) is that in the transition region from the transverse to the second train aerodynamically designed deflection are arranged like a jalousine, whereby the actual flue gas stream in layers Rear slits is guided around, while the entrained, at least coarser dust components due to inertia can not follow the flow of gas in the slots, so are enriched in a residual gas stream and then sediment out by further deflectors and by a sedation.

In the case of retrofitting an existing steam generator with the variant just described, however, a considerable pressure drop of the flue gas is to be expected, which can only be compensated again by a corresponding increase in the induced draft power, if one does not expect to suffer a power loss of the steam generator.

In this respect, a retrofit of this type forcibly means a further retrofitting of a different kind.

It is also known from DE 838676 (5Oe, 2/50) known to use the principle of gas diversion generally for filtering gases, the blinds are made as baffles and can be shaped accordingly for optimal dedusting.

Object of the invention

With the solution according to the invention, the excessively high wear on secondary heating surfaces, which occurs through the use of ballast-rich lignite, should be avoided mainly by way of retrofitting.

Explanation of the essence of the invention

The objective should be with existing steam generators with at least two trains and a Querzug only from a partial flue gas wegig the entrained by the flue gas and caused this wear components are held before the Nachschaltheizflächen.

The objective and task is essentially met by a device which is characterized by the following features:

- At the beginning of the transverse train following vertical train a baffle for deflecting a dusty boundary layer is disposed on the opposite wall of the transverse cable,

- From the baffle leads to a channel arranged on the same wall and known per se dust collector and

- At the dust collector a return to the flue gas is provided out to return the largely coarser dust largely purified flue gas back into the rest of the flue gas stream.

In the course of further refinement, it is also provided to arrange the dust separator outside the wall opposite the transverse pull and to allow the return to end in an ejacor-like manner in the second pass. The separated dust can be supplied to an existing ash removal plant.

With the help of the device according to the invention, at least the coarser, entrained by the flue gas dust components that wear the heat-up device in the second train excessively strong mechanical, can be largely withstood.

embodiment

The device according to the invention is explained below with reference to a drawing, which shows a vertical section through the second train.

The flue gas 9, which reaches from a combustion chamber (not shown) via a transverse pull 13 into a vertical second pull 8, experiences a certain separation in the region of the deflection downwards due to inertia, in that a flue gas layer 1 loaded mainly with coarse-grained flue gas bed parts is carried out on the wall 12 causing the deflection becomes. By arranging at least one baffle 2 in aerodynamic form on the wall 12, the heavily laden flue gas layer 1 can be branched off and fed via a channel 11 guided to the outside to a dust collector 3 arranged outside on the wall 12. This dust separator 3, in which adjustable baffles 4 are provided, ends at the bottom in a collecting funnel 5 for the separated dust and has a leading into the flue 8 and ejektorartig ending return line 7 for the purified of coarser flue gas components flue gas 9. The collecting funnel 5 opens via a gate valve 10 in a gravity feed line 6 for further transport of the separated dust to a deashing plant, not shown.

Claims (3)

Invention claim: 1. A device for enduring dust from flue gases within a steam generator with a second vertical train and a top connected Querzug using a dust deflector equipped with Umlenkkolben, characterized in that at the beginning of the second train (8) over its broad side of the Querzug (13 ) opposite wall (12) through a baffle (2) beginning channel (11) leads to the dust collector (3) and that the dust collector (3) on the discharge side for the purified gas via a return line (7) with the second train. (8) communicates. 2. Device according to item 1, characterized in that the dust collector (3) on the outside of the wall (12) is arranged. 3. Device according to item 1 and 2, characterized in that the return line (7) ends ejektorartig.