U.S. patent number 3,661,124 [Application Number 05/047,694] was granted by the patent office on 1972-05-09 for apparatus and process for slag deposit removal.
This patent grant is currently assigned to Foster Wheeler Corporation. Invention is credited to Justin P. Winkin.
United States Patent |
3,661,124 |
Winkin |
May 9, 1972 |
APPARATUS AND PROCESS FOR SLAG DEPOSIT REMOVAL
Abstract
An apparatus for removing slag from the heat absorption surface
in the furnace section and convection section of a heat exchanger
including at least one blast nozzle disposed proximate to the
surface and having at least two outlet orifices. A first fluid,
such as water, is delivered to one of the orifices, and a second
fluid, such as steam, is delivered to the other orifice to create a
thermal shock and mechanical force which causes the slag deposits
to separate from the heat absorption surface.
Inventors: |
Winkin; Justin P. (Fairlawn,
NJ) |
Assignee: |
Foster Wheeler Corporation
(Livingston, NJ)
|
Family
ID: |
21950416 |
Appl.
No.: |
05/047,694 |
Filed: |
June 19, 1970 |
Current U.S.
Class: |
122/392; 239/246;
239/549 |
Current CPC
Class: |
F28G
3/16 (20130101) |
Current International
Class: |
F28G
3/00 (20060101); F28G 3/16 (20060101); F28g
003/00 () |
Field of
Search: |
;239/246,549,227
;122/392 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Thieme; R. W.
Claims
What is claimed is:
1. A slag deposit removal apparatus for cleaning the heat
absorption surfaces of a vapor generator, said apparatus comprising
a plurality of blast nozzles, each comprising a body portion, at
least two fluid discharge members extending through a wall of said
body portion and perpendicular to the longitudinal axes of said
body portion; at least two fluid supply means for delivering
separate fluids to said discharge members, respectively; first
drive means for translating said discharge members between an
operative position inside said furnace and an inoperative position
outside said furnace; second drive means for rotating said
discharge members in their operative positions; and control means
for controlling the operation of said discharge members, said fluid
supply means and said first and second drive means according to a
predetermined sequence so that said fluid is discharged against at
least one of said surfaces in a manner to create a combined thermal
shock and mechanical force against said surface to cause the
separation of slag deposit therefrom.
2. The apparatus of claim 1 wherein said discharge members are in
the form of nozzles.
3. The apparatus of claim 1 wherein said predetermined sequence is
based on the buildup of slag on said surface.
4. The apparatus of claim 1 wherein said discharge members are
axially spaced along said body member.
Description
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for removing slag deposits
from a heat exchanger, and, more particularly, to an apparatus for
removing slag deposits from the heat absorption surface of the
furnace and convection sections of a vapor generator.
In the generation of power from fossil fuels utilizing vapor
generators, there is a major problem attendant in the firing of
fuels having a high alkali metal content, due to the severe slag
deposits that are formed on the heat absorption surface in the
furnace and convection section during the operation of the vapor
generator. In the past, these deposits have been avoided primarily
by restricting and blending the fuel and using additives. However,
even with this restricted use of the fuel, the problem of fouling
heat transfer surfaces has still persisted to a great degree,
rendering it necessary to use a large number of soot blowers, which
add to the cost of the vapor generator.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an
apparatus for the removal of slag deposits from the heat absorption
surface in the furnace and convection sections of a vapor generator
which does not restrict the use of the fuel and which eliminates
the use of additives, while minimizing the number of blowers
required.
Toward the fulfillment of this object the present invention
features the use of a blast nozzle comprising a hollow body member,
at least two outlet orifices extending through a wall of said body
member, first delivery means for delivering a first fluid to one of
said orifices, and second delivery means for delivering a second
fluid to the other of said orifices .
BRIEF DESCRIPTION OF THE DRAWINGS
The above brief description, as well as further objects, features,
and advantages of the present invention will be more fully
appreciated by reference to the following detailed description of
presently preferred but nonetheless illustrative embodiments in
accordance with the present invention when taken in connection with
the accompanying drawings wherein:
FIG. 1 is a partial section-partial schematic view looking at the
side and down on the furnace section of a vapor generator;
FIG. 2 is an enlarged sectional view taken along the line 2--2 of
FIG. 1; and
FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring specifically to FIG. 1 of the drawings, a portion of the
furnace section of a vapor generator is shown schematically by the
reference numeral 10. The furnace is formed by four walls, two of
which are shown by the reference numerals 12 and 14, it being
understood that corresponding walls opposite and parallel to the
walls 12 and 14 are also provided to form an enclosed
structure.
The walls 12 and 14 are of a fin-tube construction as shown
schematically, and are surrounded by insulating walls 16 and 18,
respectively. The inner surfaces of the walls 12 and 14 form the
heat absorption surface of the furnace section 10 in a relatively
heavy slag zone extending from the bottom portion of the furnace
section up to the top height thereof. A plurality of rows of
fin-tubes, shown in general by the reference numeral 20, form the
superheater portion of the furnace section 10.
According to the present invention, each wall forming the furnace
section 10, along with its corresponding insulating wall, is
provided with a plurality of openings extending therethrough for
accomodating a corresponding number of blast nozzles. For the
purpose of example, only one hole 12a and its corresponding hole
16a, is shown extending through the fin-tube wall 12 and the
insulating wall 16, it being understood that several more may be
provided in this wall and the other walls for de-slagging the
furnace walls, superheater walls in the furnace and other heat
absorbing surfaces in the convection section.
The blast nozzle is shown by the reference numeral 22, and is
adapted to be moved between a retracted position shown by the solid
lines in FIG. 1, and an extended, operative position shown by the
broken lines. This movement is achieved by means of a drive unit 24
which is connected to the nozzle 22 by means of a lance tube 26.
The drive unit is more completely described in U.S. Pat.
Application Ser. No. 759,184, filed Sept. 11, 1968 and assigned to
the assignee of the present invention, it being sufficient for the
purposes of the present application to note that it is adapted to
move along a pair of tracks 28 to and from the retracted and
extended position of the nozzle 22, and that it includes means to
impart a rotational drive to the nozzle.
A control system 30 is operatively connected to the drive unit 24
in order to control the above-mentioned movements of the nozzle 22,
and to distribute steam and water from sources 32 and 34,
respectively, to the nozzle via the drive unit 24 and the lance
tube 26. The connections between these components are shown
schematically by the reference numeral 36.
The details of the nozzle 22 are shown in FIGS. 2 and 3.
Specifically, the nozzle comprises a hollow body member 40 having a
pair of axially spaced, radially extending orifices 42 and 44
extending therethrough for respectively distributing steam and
water through the nozzle. In particular, the lance tube 26 is
directly connected to the body member 40 for supplying steam from
the source 32 to the orifice 42 via the control system 30 and the
drive unit 24. A water tube 46 is coaxially disposed within the
lance tube 26 and connects the water source 34 to the orifice 44
via the control system 30, the drive unit 24, and an elbow
connection 48. A pair of nozzles 50 and 52 are associated with the
orifices 42 and 44, and are adapted to receive the steam from the
tube 26 and the water from the tube 46, respectively, and
distribute it outwardly.
In operation, the control system 30 is programmed to periodically
actuate the drive unit 24, which moves along the tracks 28 and
causes the lance tube 26 and the nozzle 22 to move from their
retracted position to their extended position within the furnace
section 10. The nozzle 22 is continuously rotated, and distributes
steam and water outwardly through the nozzles 50 and 52,
respectively, against the inner surfaces of the walls 12 and
14.
It is understood that since several of these nozzles and associated
structure will be associated with each wall, the control system 30
is adapted to sequentially actuate the nozzles according to a
predetermined program based on the buildup of slag on the
walls.
Several variations can be made to the above without departing from
the scope of the present invention. For example, the type of fluids
dispensed from the nozzle is not limited to steam and water, but
may be in the form of other fluids, such as air or gas, etc. Also,
each nozzle can be provided with more than one orifice for
discharging its respective fluid. Of course, still other variations
of the specific construction and arrangement of the apparatus
disclosed above can be made by those skilled in the art without
departing from the invention as defined in the appended claims.
* * * * *