Note: Descriptions are shown in the official language in which they were submitted.
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US 1853
SOLIDS FEED CONTROL VALVE ASSEMBLY
BACKGROUND OF INVENTION
This invention pertains to a valve assembly for controlling
particulate solids feed, and particularly to such a control valve
assembly utilizing a purged poppet valve seat and guide bushing
con figuration for feeding particulate solids upwardly into a vessel,
such as coal to a gasifies.
The feeding of particulate solids into a vessel such as
coal into a gasifies is generally known For example, US. Patent
10 No. 2,088,679 to Yamazaki et at. shows feeding of solid fuel such
as coal to a gasifies by a horizontal screw conveyor. US. 2,667,409
to Hub Mann shows a gas producer having a poppet type valve located
at its lower outlet end for ash removal. Also the need to purge
valve seat mating surfaces for valves handling particulate solids
is generally lcnown. For example, US. 3,703,908 to Teller shows
a poppet valve and seat arrangement in which entrapped gas is
squirted through the mating seat to purge it. US. 4,188,174 to
Perkins shows a valve handling abrasive slurries in which the valve
seat is purged by a washing fluid supplied through an annular
20 outlet. Also, US. 3,470,899 to Oust shows a valve having a purged
guide bushing.
Although considerable efforts have been made in the past
to develop control valve systems suitable for reliably feeding of
particulate solids to vessels, none of the known prior art valve
arrangements have been found to be entirely satisfactory for hand-
lying the up1Ow of particulate solids into vessels such as coal
into a gasifies.
SUMMARY OF THE INVENTION
In one broad aspect, the invention pertains to
a poppet type valve assembly with gas purged seat for control-
lying flow of particulate solids there through, comprising a
valve body having a solids flow passageway therein and having
a purged valve seat located at the passageway outlet end, with
a torus-shaped manifold located radially outwardly from the
valve seat, the manifold having multiple outlet ports for
directing a purge gas flow radially inwardly toward a mating
valve head, the manifold being connected to a gas flow
passageway located within the valve body for supplying a
purge gas to the valve head. A poppet type valve head mates
with the valve seat, the head being rigidly attached to an
elongated stem, the stem passing through a packing gland
arranged for pressure sealing around the elongated stem, and
the stem being adapted for moving the valve head relative to
the valve seat. An elongated tube extends between the valve
body and the packing gland and surrounds the valve stem, and
at least one booster nozzle is located in the valve body ad-
jacent the valve stem for passing a gas there through to facilitate passage of the particulate solids through the
valve body passageway, and whereby the poppet valve head
seating surface is gas purged to remove particulate solids
therefrom.
The invention also pertains to a solids feed
and control valve assembly for feeding particulate solids up-
warmly into a fluidized bed reactor, comprising a valve body
having a seat incorporated therein, the seat being adapted
for mating with a poppet type valve head, the valve body
having an elbow-shaped solids flow passageway located up-
stream of the valve seat, with a poppet type valve head located
above and mating with the valve seat and rigidly attached to
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an elongated stem, the valve head being purged by an external
gas source, with the stem arranged for passing through a
packing gland in -the valve body for sealing around the of-
ongated stem. The stem is adapted for moving the valve head
relative to the valve seat. At least one booster nozzle is
located in the valve body near the elongated stem for passing
a gas there through to facilitate passage of particulate solids
through the flow passageway, and a horizontal rotatable ribbon
mixer and screw conveyor means feeds the particulate solids
to the elbow-shaped passageway and through the valve seat,
wherein a source of transport gas is provided at the inlet end
of the mixer and screw conveyor means to assist it moving the
solids through the mixer and screw conveyor means and to the
passageway in the valve body to permit the particulate solids
to be conveyed through the elbow-shaped passageway and valve
seat upwardly into the reactor.
The invention further pertains to a method for
feeding particulate solids through a control valve upwardly into
a reactor, comprising conveying particulate solids from a
feeder chute through a horizontal conduit and upwardly into a
flow passageway of a poppet type control valve, the control
valve including a valve body having a seating surface and a
mating valve head with stem attached thereto for controlling
operation of the valve head in the valve body, opening the
valve head a controlled amount by actuator means mechanical-
lye attached to the lower end of the valve stem, purging the
valve head by passing gas through multiple spaced openings in
a manifold attached to the valve body and encircling the
valve head, so as to purge the valve head and prevent deposits
of the particulate solids between the valve seating surface
and valve head, and passing a fluidized gas upwardly through
at least one opening located in the valve body near the valve
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stem and into the flow passageway to fluids the particulate
solids therein and facilitate flow of the particulate solids
through the valve and into the reactor.
More particularly, disclosed is a valve assembly
for particulate solids feed control for use with a fluidized
bed reactor. The valve assembly comprises a body having
an elbow-shaped flow passageway and a purged valve seat
incorporated therein, with a mating poppet type head con fig-
unction attached to the upper end of an elongated actuator
stem The actuator stem is disposed in the cast elbow-shaped
body and in a vertical tube attached to the base of the cast
elbow body and extending through a plenum chamber of a
reactor to a packing gland located external to the reactor.
The actuator stem is attached to the valve head such as by
a threaded connection, and has a Levis fixed to the stem
opposite end cooperating with an actuator means. The valve
head is a poppet-type configuration attached to the actuator
stem and cooperates with the purged valve seat located at the
top of the elbow body, thereby providing a gas purged valve
seat.
The actuator stem is made close-fitting in the
valve body lower portion so as to provide a small clearance
space there between. The actuator stem is also equipped with a
series of purge holes in the stem, thereby providing an inert
purge for cleaning and cooling the annular space between
the actuator stem and the body.
Flow of particulate solids through the valve is
facilitated by booster nozzles located in the lower portion of
the valve body. The vertical tube is equipped with a tee
connection above the packing gland for booster air inlet,
whereby a booster air supply cooperates with the multiple
booster nozzle(s) which are a series of holes in the base
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of the elbow passageway in the valve body.
The valve seat and actuator stem are located in a
cast elbow-shaped body embedded in the refractory floor of
the reactor, and the body inlet is connected to a conduit ox-
tending horizontally to a location external of the reactor.
A rotatable ribbon mixer is disposed in the horizontal
conduit, and is rotatable supported internally on each end,
and at the outer end is equipped with drive means such as a
sprocket cooperating with a rotatable mechanical drive.
A discharge chute from a rotary airlock is connected to the
outer end of the horizontal conduit above the ribbon mixer
external to the reactor. Also, an inlet tee for a transport
gas is fixed to the horizontal conduit at the lower end of
the ribbon mixer opposite the discharge chute externally
of said reactor.
The discharge chute in cooperation with transport
air conveys the particulate solids material through the
horizontal conduit into the valve body passageway. The
ribbon mixer provides for continual mixing of solids to
prevent agglomeration within the horizontal conduit into
the valve body passageway. The ribbon mixer provides for
continual mixing of solids to prevent agglomeration within
the horizontal conduit. Discharge of the particulate solids
material upwardly through the valve seat into the reactor
is assisted by the booster nozzles located around the valve
stem, and for which air flow rate is controlled external to
the reactor. The pneumatic actuator is provided externally
of the reactor for selectively moving the actuator stem
and attached valve head relative to the valve seat, so as to
control the flow of particulate solids material upwardly
into the reactor.
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BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a cross-sectional view of the solids flow control
valve assembly of the present invention.
Fig. 2 is an enlarged cross-sectional view of the lower
valve body portion showing the valve stem an purge holes therein.
Fig. 3 shows the upper portion of the poppet valve assembly
and elbow passageway downstream from a screw conveyor configuration
and arranged for weeding particulate solids upwardly into a vessel.
DESCRIPTION OF INVENTION
The invention will now be described more fully by reference
to the drawings. As shown in Fig. 1, a solids feed control valve
assembly 10 is provided for controlling the flow of particulate
solids feed into a fluidized bed reactor 11. The valve has a cast
body 12 having an elbow-shaped passageway aye and embedded in the
refractory floor 13 of the reactor. The valve body has a torus-
shaped purged valve seat 14 incorporated into the elbow-shaped body
12 with a purge gas supplied through passageway aye at connection
14b. A mating valve head 15 seats onto valve seat I and is rigidly
attached to the upper end of an elongated actuator stem 16. The
actuator stem 16 is disposed in the cast elbow body and a vertical
elongated tube 18 is attached to the base of the cast elbow body 12
and extends through a plenum chamber 19 of the reactor to a packing
gland 20 located external of the reactor. The valve body 12 and
head 15 are usually made of a casting suitable for high temperature
service, such as Hostile C-276. The actuator stem 16 is made of a
heavy gage metal tubing threaded at the upper end and attached to
the valve heat 15. A Levis 17 is fixed to the stem opposite end
and cooperates with a pneumatic actuator (not shown).
The valve head 15 is a poppet-type configuration attached
to the actuator stem 16 cooperating with the purged valve seat and
header 14 at the top of the cast elbow body 12, thereby creating
a purged valve seat arrangement
The actuator stem 16 is made close-fitting in the valve
body lower portion 12b so as to provide a small radial clearance
space 24 between the stem and the body. If desired, a replaceable
bushing 25 may be provided in the body close fitting around stem 16.
As shown in detail in Fig. 2, the actuator stem is also equipped with
at least two purge holes 22 in the wall of stem 16, thereby providing
for an inert gas purge for cleaning the annular space 24 and also
cooling the valve stem 16. The radial clearance between the stem
and body or bushing is usually 0.010 0.030 inch.
For facilitating the reliable flow of particulate solids
through the valve body elbow-shaped passageway, at least one booster
nozzle 26 is provided in the body 12 radially outwardly from clearance
space 24 The vertical tube 13 it equipped with a tee connection
28 above the packing gland 20 for sealing around the stem 16. A
booster air surly is provided at tee 28, whereby the booster air
passes through booster nozzle(s) 26 which are provided in the base
of the cast elbow body 12.
As shown in Fig. 3, the valve body elbow inlet is attached
to a conduit 30 extending horizontally to a location external to the
reactor. A rotatable ribbon mixer or screw conveyor 32 is disposed
in the horizontal conduit 30, and supported internally on one end
by bearing 34 and support members aye, and at the outer end by bear
in 36. The mixer shaft 35 is rotated by suitable means such as a
sprocket 37 cooperating with a mechanical drive means (not shown).
A discharge chute 40 from a rotary airlock (not shown) is connect-
30 Ed to the horizontal conduit 30 inlet end above the ribbon mixer
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and external of the reactor. Also, an inlet tee 43 for a -trays-
port gas such as air is attached to the horizontal conduit 30
to the rear of the ribbon mixer and opposite to the discharge
chute 40 external of the reactor.
In operation or feeding particulate solids such as coal
and/or lime into the reactor, the discharge chute 40 in cooperation
with transport air conveys the particulate solids material through
the horizontal conduit 30 into the flow passageway aye in cast body-
elbow 12. The ribbon mixer 32 provides for continual mixing to
~10 prevent solids agglomeration within the horizontal conduit. The
discharge of solids material into the reactor is assisted by the
booster nozzles 26, for which air flow is controlled externally
of the reactor. A pneumatic actuator it provided externally of
the reactor for selectively moving the actuator stem 16 and valve
head 15 relative to the valve seat 14, to control the upward flow
of particulate solids material into the reactor.
Although the invention has been described broadly and in
terms of preferred embodiments, it will be understood that various
modifications and variations can be made and that some features can
be employed without others, all within the spirit and scope of the
invention which is defined solely by the following claims.
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