CA2217503A1 - A non-mechanical valve - Google Patents
A non-mechanical valve Download PDFInfo
- Publication number
- CA2217503A1 CA2217503A1 CA002217503A CA2217503A CA2217503A1 CA 2217503 A1 CA2217503 A1 CA 2217503A1 CA 002217503 A CA002217503 A CA 002217503A CA 2217503 A CA2217503 A CA 2217503A CA 2217503 A1 CA2217503 A1 CA 2217503A1
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- CA
- Canada
- Prior art keywords
- valve
- solids
- flow
- aeration gas
- legs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
- B01J8/0025—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor by an ascending fluid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G53/00—Conveying materials in bulk through troughs, pipes or tubes by floating the materials or by flow of gas, liquid or foam
- B65G53/04—Conveying materials in bulk pneumatically through pipes or tubes; Air slides
- B65G53/16—Gas pressure systems operating with fluidisation of the materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
- B01J8/003—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor in a downward flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C10/00—Fluidised bed combustion apparatus
- F23C10/18—Details; Accessories
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A non-mechanical valve (3) for controlling the flow of fluidisable solids is disclosed. The valve (3) comprises a pipe having an upstream leg (5) with a solids inlet (13) at an upper end, a downstream leg (7) with a solids outlet (14) at an upper end, and a base section (9) interconnecting lower ends of the legs (5, 7). The valve (3) further comprises a means for introducing aeration gas into each of the legs (5, 7) to maintain fluidised flow of solids through the valve (3) and a means for adjusting the flow of aeration gas to the legs (5, 7) to control the solids flow through the valve (3).
Description
A NCnN ~ T~T. V~L~ne The ~resent invention rQlates to a non-me~h~n~cal - valve for fine-grained ~olid~ materials.
Controllea solids feed into and from a fluidi~ed bed ~roces~in~ unit is often a dominA~t requirement Çor succe~8ful o~eration of the unit. Failure to achieve controllea ~olids flow can render the unit inoperable.
Therefore, the devel~ - ~ o r a reliable solid~ handling sy8tem re~reRe~t~ a strong economic le~erage point in the develo~ment of a f~ ed bed ~roce3sing unit. The ~ame applies to other types o~ ~rocessing unit ~eg rotary kiln) -h;Ch treat fl~ ;r-hl~ materials, even if the solid~ are not fluiaised whilst being treated.
In general, difficultie~ with solids handling are ~ ~ed by tem~erature effects. If the feed ~olids of a ~ c~8 are at (or close to) ~mbient temperature then co.,v .~iQnAl solids handling strategies can be a~lied with moaest risk. For a low-t~ ature (i.e. les~ than 750~C) ~ ;8e~ bed ~rocess mech~;cal valve~ can be em~loyed for controlled removal of ~olids provided the fl~ bed material is not unduly sticky, chemically aggre~s;ve, or difficult to h~ndle in terms of fouling o~ the valve me~h~n;~m.
The ~ame is not true for ~ol~ds ~ val from a Çluidi~ed bed process which operates At temperatures above 750~C. In thi~ tem~erature range it is generally not advisable to u~e - h~n; cal valves even tho~h such valves are used in a ~umber of industrial a~plications and in 80me cases with satisfactory rQsults. In general, meçhAn;r~l valves for hot solids a~l~cation~ need to be re-de~elo~ed for each a~lication and this i~ both time-consuming and =
co~tly. A further factor i~ that on-going maintenance i8 expensive. In the final analysi~, if a ~im~le non-mechanical alternati~e was a~ail~ble, it would be a preferable o~tion to a ~ n; cal valve.
~on-~ech~cAl valves for fl~ r~ beda ha~e been reviewed in an article entitled ~'Non-me~hAn;cal Solids Feea and Recycle Devices for Circulating Fluldised Beds~ by .M. Rnowlton Dubli~hed in the E ocee~;ngs of the .S~CQn~
International Conference on Circulating Fluidised Bsd~, Com~iegne, r ~'e~ 14-18 March 1988, ~ 31-41. In di8cusaing h-~alvea, ~-Yalve8, and V-valve~, T.M. ~nowlton concludes that o~eration in "valve" mode (ie controlled solids flow) re~uires the presence of a aefluidised, ~e~
bed of sol~ds. By way of example, in an ~-valve a ~A~e~
bed is formed in the hor~o~Al section and aeration gas i~
admitted a short dist~nce above the elbow. Ga~ drag through the ~AC~9~ bed c~ es the solida to mo~e ~n the d~rect~on o~ discharge and the efflux rate is ~ensitive to how much gas ~lows through the ~Acke~ bed in this m~nner.
By modulating the _mount of aeration gas it i~ ~ossible to ~ary the ~iech~ge rate of solids.
Thi~ type of non-mechAnicAI ~al~e works well when the solids are coarse (sand-like) and non-sticky. Ho~_v~ , any sti~ki~oe~ will result in the ~k~ bed forming an immo~able solid ~lug and the ~al~e will cease to ~unction.
Co..~,elsely, if the solids are too fine (eg fl~ ~A;~
cr~c~;ng catalyst), they will not defluidi~e ~ast ~no~gh to form a ~ac~ed bed when re~uired. As a co~ocuence, solids flow through the valve will be high and ~n~n~rolled. The val~e may be turned off by sto~ping aeration ga~ flow, but the flow rate will return to a high-rate condition as ~oon a~ aeration is rQstarted. The result is a 108~ of flow-rate control and the ~al~e functions only a~ an ~on-o~f"
de~ice. If the de-aeration time of the ~olid~ is high eno~g~ (as i~ the case with high fines level~ in the CA 02217503 1997-10-06 =
WO96/31418 PCTIAU96tOO196 ~owder) then the flow of material will not sto~ at all when aeration gas i~ turned off.
T.M. Rnowlton ao~cribe~ 1OO~8Q~1_ and ~eal-~ots a~ "Automatic" aeviees whieh do not have a ~olid flow control function. Most modern circulating fl~ e~ bed (CFB) syQtems use loo~eal~ for ret~n; ng solids from the cyelone to the riser. Solids pass through a loop~eal at whatever rate they a~roach the 100PBea1 inlet and overall ~olids circulation rate control is ~chieved by other mean~.
In this case the lo~ al operates purely _B a ~re~ure ~Al~n~ing aevice, rece4ving solids ~rom a CFB cyelone under-flow at one yre~ure and delivering the ~olid~ to the bottom of the riser at a higher pressure. In this ronteYt, it ean only o~erate eorreetly i4 the sol4ds feed i~ "non-flooded~, ie limited by an external con~traint rather thanby f low re~;stance w~thin the 1G~3~ tself. For a "floo~e~" sol;ds feed a~l~cation the loo~eal woula g$ve an ~ on~ollably high ~olids di~charge.
There i8 currently no suitable non-me~-~hAnieal _olias flow eontrol valve for f;ne, hot ~o~ 8 ;-' 4t~h can form lum~s if they are not fully flu~di~ed at all t~mes.
The ~-valve family of valves i~ unsuita~le due to the need for a ~e~ bed and the lack o$ control for fine ~o.-~e~8.
The loo~eal and its rQlatives do not offer ~co~e for flow -' lAtion v4a aerat$on control.
An ob~ect of the pre~ent invention i~ to ~rov~de a non e~hAn; CAl valve that is not ubjeet to the above de~cribed Qhorteom~ng~ and allow~ non e hAn~eal flow eontrol for fine, sticky solids.
Aecording to the ~resent invention there ;~
provided a non-meeh~n~q~ ~alve for controlling the flow of fl~ hle solids, the valve eom~rising:
CA 02217503 1997-10-06 ' -- -Wo96/31418 PCT/AU96/00l96 (i) a ~ipe having an inlet for solid~ at one end and an outlet for solids at the other end, the ~$~e compri~ing two u~ ~A~ng legs and a ba~e ~ection r~. nc~ing togQther lower end~ of the leg~;
(ii) a means for introducing ~eration ga~ into each of the leg~ to ma;~t~in flu~aisQd ~low of solids through the ~al~e;
(iii) a moans for ad~u~ting the flow of aeration ga~ to the legs to control the flow of solld~ through the ~alve.
~he term "~i~e" is understood herein to mean any form o~ duct, of circular or non-circular cro~-section, that i~ ca~able of con~;ng ~luidisable solid~.
It iB ~reSerred tbat the aeration gas introduction mean~ com~ri~es at lea~t one aeration ga~
inlet in each leg.
It i~ ~referred that the aeration gas introduction mean~ compri~e~ a mean~ Sor deli~ering aeration gas to each aeration ga~ inlet.
It i~ ~referred that the aeration ga~
introduction meanQ compri~es at lea~t one aeration gas ~nlet in the base ~ection.
~ t i~ ~reSerred that the aeration gas delivery means be ada~ted to deli~er aeration gas to the or each inlet in the base section.
The ba~e sQction may be hori~o~t~l, angled or any other ~uitable ~ ry.
W O96/31418 PCTtAU96/00196 According to the ~re~ont in~rention there i~ al80 pro~ided a method of ~low control of ~ ~le ~olids by means of a non-mech~n;cal val~e com~rising a ~i~e having a ~olia~ inlet ~d a ~olids outlet, the ~ipe comprising two up~t~ ~g leg~ and a base ~ection connecting together lower end~ of the legs, the method Com~riBing:
(i) i~t~;~;~ the val~e flooded with solids;
(ii) injecting aeration ga8 ~nto each leg to m~nt~;n solids flowing in the valve from the inlet to the outlet in a fluidi~ed state; and (iii) controlling aeration gas injection into the legs to control the ~low o~ solids through the ~al~e.
It iB ~re~erred that ~tep (iii) com;pri~e~
increa~ing or decreasing the flow o~ aeration gas into one leg compared with the other leg to control the flow of solids through the ~al~e.
The ~re~ent inV~nt-;on iB de~cribed further by way o~ example with reference to the accom~anying drawing, in which:
Figure 1 iB a ~artly diagrammatic ~rertical section of a ~referred embodiment of a non-merhan;cal ~alve of the pre~ent in~ention;
Figure 2 is a gra~h which show~ the variation of presRure in the ~al~e ~hown in Figure 1: and Figure 3 i~ a ~artly aiagrammatic ~ertical section of a gra~h illuPtrating the ~res~ure ~ariation for two non- ~:han; cal valves o~ the ty~e shown in Figure having di~ferent de~ths.
With reference to Figure 1, the ~referred embodiment of the non-mech~nical valve 3 compri~es a generally ~_~h~ e ~aving two leg8 5, 7 intercQrn~ted by a hori~o~t~l base section 9. The leg 5 includes a solid~ inlet 13 And the leg 7 includes a solids outlet 14 that i8 connQcted to a solids outlet chute 15.
The ~al~e 3 further comprises:
(i) aeration inlet~, Port 1 and Port 2, for introducin~ seration ga~ into the leg 5;
(ii) aeration inlets, Port 3 and Port 4, for introducing aeration gas into the horizontal section 9; and (lii) an aeration $nlet, Port 5, for introducing aeration gas into the leg 7.
The ~alve 3 ~urther comprise~ a means (not shown) for 3u~1ying aeration ~as to each of the aeration inlets, Ports 1 to 5. ~he ~ur~o~e o~ th~ aer~tion ~as i8 to ~;~t~;n solids in the valve 3 in a fl~ ;7-~ state and to allow the valve 3 to be o~erated on the ~rinci~le of di~ferential ~ressure gr~;~n~ in each of the legs 5, 7 in order to control the flow of ~olids in the valve 3.
In accordance with this ~rinciple, ~ol~ds entering 801~d8 inlet 13 at ~oint A are ke~t fluidised as they ~ass down leg 5 to point B ~y gas ~rom the aeration inlets Port 1 ~nd Port 2. The ~ ;r~tion regime is such that gas bubbles~slugs ~ass upward from the elbow t~oint B) inside leg 5 toward ~oint A, countercurrent to the passage of solids.
~ - CA 02217~03 1997-10-06 ~ : -W096/314l8 pcTlAvs6loo1s6 From ~oint B the solias ~a~s along the horizontal section 9 ana then u~wards in leg 7 to ~oint C, again being ke~t fluidised by the aeration inlets Port 3, Port 4, ana - ~ort 5. The le~ 7, ~z ~o~nt B to ~o~nt C, operates with sol~ds and gas bubbles/slugs flowing in co-current u~flow.
From ~oint C the solids Da~s ~a the sol~ds outlet chute 15 to the valve outlet at ~o~nt D .
With reference to Figure 2, the pres~ure on solids in the valve 3 increa~e~ a~ the solid~ flow downwardly through le~ 5 $rom point A to ~oint B and thereafter decreases as the solias flow u~ward~ through leg 7 from ~oint B to ~o~nt C. ~he slo~e of the lines ~hown in Figure 2, which determines the extent of ~res~ure var;ation of the val~e 3, is a function of the ~mount of aeration gas su~lied to val~e 3 v$a the Ports 1 - 5.
~ he control of eol;~ flow is achieved by varyin~
the amount of aeration gas su~lied to each of the leg~ 5, 7. The extent of aeration in oach leg 5, 7 deto ~e8 the voidage, with an incr~ase in aeration tra~slating to a monotonic, ~redictable increase in time averaged voidage.
Since ~res~ure differential acros~ a fluidisea bed is a strong function of voidage, the dri~ing force for solids to move through the ~alve 3 can be controlled directly by contsolling the ~ressure differential.
S~ecifically, increasing the f low of aeration gas to leg 7 rsAnces the ~ 3~ e graA;en~ in leg 7 and therefore incrQases the driving force in u~tream leg 5.
A~ a consequence, there i~ an increa~ed flow of solids through the valve 3. Furthermore, increasing the flow of aeration gas to leg 5 rsA~ces the pressure gradient in le~
5 and therefore reA~css the dr~ving force in u~stream leg 5. As a consequence, there i~ a decreased flow of solid~
through the valve 3.
~~ CA 02217S03 1997-10-06 ~~~~~
W 096/31418 PCTIA~96100196 The ~ressure~ at ~ointB A ana D will generally not be the same. If ~oints A and D are at the same ~ros~ure, then the lensJth (~1) of leg 5 and the length (~2) of 1~ 7 will be ~ GAimatQly the s~. Assuming that the diameter~ of the legEI 5, 7 are the 8ame~ if ~olnt A is at a h;ghe~ ~res~ure than ~oint D, then dimen~on Ll will be longer ~com~arQd with the equal-~rQla~ure ca~e) by an r ~t which corres~o~d~ to the height of fluidi8ed bed ~eeA~ to gener~te the difforence in ~res~ures. Furthermore, with the ~ame assum;ption, ~f point A i5 at a lower pre~ure than ?oint D, then dimen~ion I-2 Will be longer by the corre~ ~;~Sr r Control ~en~iti~ity of the system will be ~roportio~lal to the de~th o~ the ~ralve 3, where "de~th" i8 defined a~ the ~rert~cal aistance ovor ~-~?1 .~h the flu~ Qa bed is common to both legs 5, 7. Thi~ can bQst be illustrat~d by referencQ to Figure 3 Wh~lC~ BhOW8 two val~res 3a, 3b of the type shown in Figures 1 and 2 of d~ferent de~ths and the same diameter for each leg 5, 7, ~nd gra~he of the ~ari~t~on of ~rQssure along the length of each ~al~e 3a, 3b. It can reaaily be a~ec~ated from a ~-~ r~ on of the gra~h~ thnt the ~res~ure range o~ each valve 3 iB
directly ~ro~ortional to the de~th o~ the val~e 3, wlth the val~e 3b having the h~gher common length of legs 5, 7 have a higher pre~ure ~ariation.
The ~re~ure ~ariation is an im~ortant ~arameter hecA~e it iB an ir~A;C~tlon of the o~erating ~ressure ran~e of the valve. S~ecifically, if the de~th i~ insufficient, then the range o~er wh~ch the pre~ure dri~ing force for solids flow can be ~raried i8 small. The re~ult iB a ~?oor control range. In general it i8 desirable to o~erate the ~alve 3 of t~e type shown in Figure~ 1 to 3 with a flu~disea be~ depth greater than lm, ~referably greater than 3m.
~rB
_ g The ~alve 3 ha~ a ~ignificant self-stabilising feature which make8 it ~art;~ Arly attracti~e for control ~u ~Le8. If the valve 3 ~8 at a stable flow condition ~nd an extsrn~l fluctu~tion ~ n ~olids ~low rate ~nto the valve 3 to increa~e, the ~e~o..se is a decline in ~res~ure rise A-B and a corres~o~A~n~ i~crease in ~ressure dro~ B-C.
The net driving force for solids to pass through valve 3 is thu8 decreasea and solids flow rate iB ~erturbated back toward ~ts ~re-u~set cond~tion. A mirror image of thi~
o~erates when solids flow rate decrea~es into the valve 3.
Thi~ self-~tahili~ing feature imp~rts good operating characteristics and makes valve 3 well-~uited for automatic flow control.
In order to evaluate valve 3, an industrial circulating flv~A~ bed sy~tem for iron ore pre-reauction wa~ f~tted with the valve 3. The valve 3 comprised a 200mm ID ~i~e w~th a 6m dee~ downflow leg 5 and a 6m long lSOmm ID u~flow leg 7. Aeration gas wa~ added as shown in Figure 1. The ~ressure differential acro~ the valve 3 wa~ 5-10 kPa, w~th the solid~ ~nlet 13 to the valve 3 being at the h~ ghe~ ~re88ure. Aeration rates were adjusted such that gas velocities in each of the two legs 5, 7 were in the range 0.1 to 0.5 m/s. Iron ore with an average part~cle ~ize of 50 microns was used succe~sfully in the valve 3.
Many modification~ may be made to the ~referred emhoAiment o~ the val~e shown in the figures without de~artlng from the s~irit and sco~e of the ~re~ent invention.
Controllea solids feed into and from a fluidi~ed bed ~roces~in~ unit is often a dominA~t requirement Çor succe~8ful o~eration of the unit. Failure to achieve controllea ~olids flow can render the unit inoperable.
Therefore, the devel~ - ~ o r a reliable solid~ handling sy8tem re~reRe~t~ a strong economic le~erage point in the develo~ment of a f~ ed bed ~roce3sing unit. The ~ame applies to other types o~ ~rocessing unit ~eg rotary kiln) -h;Ch treat fl~ ;r-hl~ materials, even if the solid~ are not fluiaised whilst being treated.
In general, difficultie~ with solids handling are ~ ~ed by tem~erature effects. If the feed ~olids of a ~ c~8 are at (or close to) ~mbient temperature then co.,v .~iQnAl solids handling strategies can be a~lied with moaest risk. For a low-t~ ature (i.e. les~ than 750~C) ~ ;8e~ bed ~rocess mech~;cal valve~ can be em~loyed for controlled removal of ~olids provided the fl~ bed material is not unduly sticky, chemically aggre~s;ve, or difficult to h~ndle in terms of fouling o~ the valve me~h~n;~m.
The ~ame is not true for ~ol~ds ~ val from a Çluidi~ed bed process which operates At temperatures above 750~C. In thi~ tem~erature range it is generally not advisable to u~e - h~n; cal valves even tho~h such valves are used in a ~umber of industrial a~plications and in 80me cases with satisfactory rQsults. In general, meçhAn;r~l valves for hot solids a~l~cation~ need to be re-de~elo~ed for each a~lication and this i~ both time-consuming and =
co~tly. A further factor i~ that on-going maintenance i8 expensive. In the final analysi~, if a ~im~le non-mechanical alternati~e was a~ail~ble, it would be a preferable o~tion to a ~ n; cal valve.
~on-~ech~cAl valves for fl~ r~ beda ha~e been reviewed in an article entitled ~'Non-me~hAn;cal Solids Feea and Recycle Devices for Circulating Fluldised Beds~ by .M. Rnowlton Dubli~hed in the E ocee~;ngs of the .S~CQn~
International Conference on Circulating Fluidised Bsd~, Com~iegne, r ~'e~ 14-18 March 1988, ~ 31-41. In di8cusaing h-~alvea, ~-Yalve8, and V-valve~, T.M. ~nowlton concludes that o~eration in "valve" mode (ie controlled solids flow) re~uires the presence of a aefluidised, ~e~
bed of sol~ds. By way of example, in an ~-valve a ~A~e~
bed is formed in the hor~o~Al section and aeration gas i~
admitted a short dist~nce above the elbow. Ga~ drag through the ~AC~9~ bed c~ es the solida to mo~e ~n the d~rect~on o~ discharge and the efflux rate is ~ensitive to how much gas ~lows through the ~Acke~ bed in this m~nner.
By modulating the _mount of aeration gas it i~ ~ossible to ~ary the ~iech~ge rate of solids.
Thi~ type of non-mechAnicAI ~al~e works well when the solids are coarse (sand-like) and non-sticky. Ho~_v~ , any sti~ki~oe~ will result in the ~k~ bed forming an immo~able solid ~lug and the ~al~e will cease to ~unction.
Co..~,elsely, if the solids are too fine (eg fl~ ~A;~
cr~c~;ng catalyst), they will not defluidi~e ~ast ~no~gh to form a ~ac~ed bed when re~uired. As a co~ocuence, solids flow through the valve will be high and ~n~n~rolled. The val~e may be turned off by sto~ping aeration ga~ flow, but the flow rate will return to a high-rate condition as ~oon a~ aeration is rQstarted. The result is a 108~ of flow-rate control and the ~al~e functions only a~ an ~on-o~f"
de~ice. If the de-aeration time of the ~olid~ is high eno~g~ (as i~ the case with high fines level~ in the CA 02217503 1997-10-06 =
WO96/31418 PCTIAU96tOO196 ~owder) then the flow of material will not sto~ at all when aeration gas i~ turned off.
T.M. Rnowlton ao~cribe~ 1OO~8Q~1_ and ~eal-~ots a~ "Automatic" aeviees whieh do not have a ~olid flow control function. Most modern circulating fl~ e~ bed (CFB) syQtems use loo~eal~ for ret~n; ng solids from the cyelone to the riser. Solids pass through a loop~eal at whatever rate they a~roach the 100PBea1 inlet and overall ~olids circulation rate control is ~chieved by other mean~.
In this case the lo~ al operates purely _B a ~re~ure ~Al~n~ing aevice, rece4ving solids ~rom a CFB cyelone under-flow at one yre~ure and delivering the ~olid~ to the bottom of the riser at a higher pressure. In this ronteYt, it ean only o~erate eorreetly i4 the sol4ds feed i~ "non-flooded~, ie limited by an external con~traint rather thanby f low re~;stance w~thin the 1G~3~ tself. For a "floo~e~" sol;ds feed a~l~cation the loo~eal woula g$ve an ~ on~ollably high ~olids di~charge.
There i8 currently no suitable non-me~-~hAnieal _olias flow eontrol valve for f;ne, hot ~o~ 8 ;-' 4t~h can form lum~s if they are not fully flu~di~ed at all t~mes.
The ~-valve family of valves i~ unsuita~le due to the need for a ~e~ bed and the lack o$ control for fine ~o.-~e~8.
The loo~eal and its rQlatives do not offer ~co~e for flow -' lAtion v4a aerat$on control.
An ob~ect of the pre~ent invention i~ to ~rov~de a non e~hAn; CAl valve that is not ubjeet to the above de~cribed Qhorteom~ng~ and allow~ non e hAn~eal flow eontrol for fine, sticky solids.
Aecording to the ~resent invention there ;~
provided a non-meeh~n~q~ ~alve for controlling the flow of fl~ hle solids, the valve eom~rising:
CA 02217503 1997-10-06 ' -- -Wo96/31418 PCT/AU96/00l96 (i) a ~ipe having an inlet for solid~ at one end and an outlet for solids at the other end, the ~$~e compri~ing two u~ ~A~ng legs and a ba~e ~ection r~. nc~ing togQther lower end~ of the leg~;
(ii) a means for introducing ~eration ga~ into each of the leg~ to ma;~t~in flu~aisQd ~low of solids through the ~al~e;
(iii) a moans for ad~u~ting the flow of aeration ga~ to the legs to control the flow of solld~ through the ~alve.
~he term "~i~e" is understood herein to mean any form o~ duct, of circular or non-circular cro~-section, that i~ ca~able of con~;ng ~luidisable solid~.
It iB ~reSerred tbat the aeration gas introduction mean~ com~ri~es at lea~t one aeration ga~
inlet in each leg.
It i~ ~referred that the aeration gas introduction mean~ compri~e~ a mean~ Sor deli~ering aeration gas to each aeration ga~ inlet.
It i~ ~referred that the aeration ga~
introduction meanQ compri~es at lea~t one aeration gas ~nlet in the base ~ection.
~ t i~ ~reSerred that the aeration gas delivery means be ada~ted to deli~er aeration gas to the or each inlet in the base section.
The ba~e sQction may be hori~o~t~l, angled or any other ~uitable ~ ry.
W O96/31418 PCTtAU96/00196 According to the ~re~ont in~rention there i~ al80 pro~ided a method of ~low control of ~ ~le ~olids by means of a non-mech~n;cal val~e com~rising a ~i~e having a ~olia~ inlet ~d a ~olids outlet, the ~ipe comprising two up~t~ ~g leg~ and a base ~ection connecting together lower end~ of the legs, the method Com~riBing:
(i) i~t~;~;~ the val~e flooded with solids;
(ii) injecting aeration ga8 ~nto each leg to m~nt~;n solids flowing in the valve from the inlet to the outlet in a fluidi~ed state; and (iii) controlling aeration gas injection into the legs to control the ~low o~ solids through the ~al~e.
It iB ~re~erred that ~tep (iii) com;pri~e~
increa~ing or decreasing the flow o~ aeration gas into one leg compared with the other leg to control the flow of solids through the ~al~e.
The ~re~ent inV~nt-;on iB de~cribed further by way o~ example with reference to the accom~anying drawing, in which:
Figure 1 iB a ~artly diagrammatic ~rertical section of a ~referred embodiment of a non-merhan;cal ~alve of the pre~ent in~ention;
Figure 2 is a gra~h which show~ the variation of presRure in the ~al~e ~hown in Figure 1: and Figure 3 i~ a ~artly aiagrammatic ~ertical section of a gra~h illuPtrating the ~res~ure ~ariation for two non- ~:han; cal valves o~ the ty~e shown in Figure having di~ferent de~ths.
With reference to Figure 1, the ~referred embodiment of the non-mech~nical valve 3 compri~es a generally ~_~h~ e ~aving two leg8 5, 7 intercQrn~ted by a hori~o~t~l base section 9. The leg 5 includes a solid~ inlet 13 And the leg 7 includes a solids outlet 14 that i8 connQcted to a solids outlet chute 15.
The ~al~e 3 further comprises:
(i) aeration inlet~, Port 1 and Port 2, for introducin~ seration ga~ into the leg 5;
(ii) aeration inlets, Port 3 and Port 4, for introducing aeration gas into the horizontal section 9; and (lii) an aeration $nlet, Port 5, for introducing aeration gas into the leg 7.
The ~alve 3 ~urther comprise~ a means (not shown) for 3u~1ying aeration ~as to each of the aeration inlets, Ports 1 to 5. ~he ~ur~o~e o~ th~ aer~tion ~as i8 to ~;~t~;n solids in the valve 3 in a fl~ ;7-~ state and to allow the valve 3 to be o~erated on the ~rinci~le of di~ferential ~ressure gr~;~n~ in each of the legs 5, 7 in order to control the flow of ~olids in the valve 3.
In accordance with this ~rinciple, ~ol~ds entering 801~d8 inlet 13 at ~oint A are ke~t fluidised as they ~ass down leg 5 to point B ~y gas ~rom the aeration inlets Port 1 ~nd Port 2. The ~ ;r~tion regime is such that gas bubbles~slugs ~ass upward from the elbow t~oint B) inside leg 5 toward ~oint A, countercurrent to the passage of solids.
~ - CA 02217~03 1997-10-06 ~ : -W096/314l8 pcTlAvs6loo1s6 From ~oint B the solias ~a~s along the horizontal section 9 ana then u~wards in leg 7 to ~oint C, again being ke~t fluidised by the aeration inlets Port 3, Port 4, ana - ~ort 5. The le~ 7, ~z ~o~nt B to ~o~nt C, operates with sol~ds and gas bubbles/slugs flowing in co-current u~flow.
From ~oint C the solids Da~s ~a the sol~ds outlet chute 15 to the valve outlet at ~o~nt D .
With reference to Figure 2, the pres~ure on solids in the valve 3 increa~e~ a~ the solid~ flow downwardly through le~ 5 $rom point A to ~oint B and thereafter decreases as the solias flow u~ward~ through leg 7 from ~oint B to ~o~nt C. ~he slo~e of the lines ~hown in Figure 2, which determines the extent of ~res~ure var;ation of the val~e 3, is a function of the ~mount of aeration gas su~lied to val~e 3 v$a the Ports 1 - 5.
~ he control of eol;~ flow is achieved by varyin~
the amount of aeration gas su~lied to each of the leg~ 5, 7. The extent of aeration in oach leg 5, 7 deto ~e8 the voidage, with an incr~ase in aeration tra~slating to a monotonic, ~redictable increase in time averaged voidage.
Since ~res~ure differential acros~ a fluidisea bed is a strong function of voidage, the dri~ing force for solids to move through the ~alve 3 can be controlled directly by contsolling the ~ressure differential.
S~ecifically, increasing the f low of aeration gas to leg 7 rsAnces the ~ 3~ e graA;en~ in leg 7 and therefore incrQases the driving force in u~tream leg 5.
A~ a consequence, there i~ an increa~ed flow of solids through the valve 3. Furthermore, increasing the flow of aeration gas to leg 5 rsA~ces the pressure gradient in le~
5 and therefore reA~css the dr~ving force in u~stream leg 5. As a consequence, there i~ a decreased flow of solid~
through the valve 3.
~~ CA 02217S03 1997-10-06 ~~~~~
W 096/31418 PCTIA~96100196 The ~ressure~ at ~ointB A ana D will generally not be the same. If ~oints A and D are at the same ~ros~ure, then the lensJth (~1) of leg 5 and the length (~2) of 1~ 7 will be ~ GAimatQly the s~. Assuming that the diameter~ of the legEI 5, 7 are the 8ame~ if ~olnt A is at a h;ghe~ ~res~ure than ~oint D, then dimen~on Ll will be longer ~com~arQd with the equal-~rQla~ure ca~e) by an r ~t which corres~o~d~ to the height of fluidi8ed bed ~eeA~ to gener~te the difforence in ~res~ures. Furthermore, with the ~ame assum;ption, ~f point A i5 at a lower pre~ure than ?oint D, then dimen~ion I-2 Will be longer by the corre~ ~;~Sr r Control ~en~iti~ity of the system will be ~roportio~lal to the de~th o~ the ~ralve 3, where "de~th" i8 defined a~ the ~rert~cal aistance ovor ~-~?1 .~h the flu~ Qa bed is common to both legs 5, 7. Thi~ can bQst be illustrat~d by referencQ to Figure 3 Wh~lC~ BhOW8 two val~res 3a, 3b of the type shown in Figures 1 and 2 of d~ferent de~ths and the same diameter for each leg 5, 7, ~nd gra~he of the ~ari~t~on of ~rQssure along the length of each ~al~e 3a, 3b. It can reaaily be a~ec~ated from a ~-~ r~ on of the gra~h~ thnt the ~res~ure range o~ each valve 3 iB
directly ~ro~ortional to the de~th o~ the val~e 3, wlth the val~e 3b having the h~gher common length of legs 5, 7 have a higher pre~ure ~ariation.
The ~re~ure ~ariation is an im~ortant ~arameter hecA~e it iB an ir~A;C~tlon of the o~erating ~ressure ran~e of the valve. S~ecifically, if the de~th i~ insufficient, then the range o~er wh~ch the pre~ure dri~ing force for solids flow can be ~raried i8 small. The re~ult iB a ~?oor control range. In general it i8 desirable to o~erate the ~alve 3 of t~e type shown in Figure~ 1 to 3 with a flu~disea be~ depth greater than lm, ~referably greater than 3m.
~rB
_ g The ~alve 3 ha~ a ~ignificant self-stabilising feature which make8 it ~art;~ Arly attracti~e for control ~u ~Le8. If the valve 3 ~8 at a stable flow condition ~nd an extsrn~l fluctu~tion ~ n ~olids ~low rate ~nto the valve 3 to increa~e, the ~e~o..se is a decline in ~res~ure rise A-B and a corres~o~A~n~ i~crease in ~ressure dro~ B-C.
The net driving force for solids to pass through valve 3 is thu8 decreasea and solids flow rate iB ~erturbated back toward ~ts ~re-u~set cond~tion. A mirror image of thi~
o~erates when solids flow rate decrea~es into the valve 3.
Thi~ self-~tahili~ing feature imp~rts good operating characteristics and makes valve 3 well-~uited for automatic flow control.
In order to evaluate valve 3, an industrial circulating flv~A~ bed sy~tem for iron ore pre-reauction wa~ f~tted with the valve 3. The valve 3 comprised a 200mm ID ~i~e w~th a 6m dee~ downflow leg 5 and a 6m long lSOmm ID u~flow leg 7. Aeration gas wa~ added as shown in Figure 1. The ~ressure differential acro~ the valve 3 wa~ 5-10 kPa, w~th the solid~ ~nlet 13 to the valve 3 being at the h~ ghe~ ~re88ure. Aeration rates were adjusted such that gas velocities in each of the two legs 5, 7 were in the range 0.1 to 0.5 m/s. Iron ore with an average part~cle ~ize of 50 microns was used succe~sfully in the valve 3.
Many modification~ may be made to the ~referred emhoAiment o~ the val~e shown in the figures without de~artlng from the s~irit and sco~e of the ~re~ent invention.
Claims (8)
1. A non-mechanical valve for controlling the flow of fluidisable solids, the valve comprising:
(i) a pipe having an inlet for solids at one end and an outlet for solids at the other end, the pipe comprising two upstanding legs and a base section connecting together lower ends of the legs;
(ii) a means for introducing aeration gas into each of the legs to maintain fluidised flow of solids through the valve;
(iii) a means for adjusting the flow of aeration gas to the legs to control the flow of solids through the valve.
(i) a pipe having an inlet for solids at one end and an outlet for solids at the other end, the pipe comprising two upstanding legs and a base section connecting together lower ends of the legs;
(ii) a means for introducing aeration gas into each of the legs to maintain fluidised flow of solids through the valve;
(iii) a means for adjusting the flow of aeration gas to the legs to control the flow of solids through the valve.
2. The valve defined in claim 1 wherein the aeration gas introduction means comprises at least one aeration gas inlet in each leg.
3. The valve defined in claim 2 wherein the aeration gas introduction means comprises a means for delivering aeration gas to each aeration gas inlet.
4. The valve defined in claim 3 wherein the aeration gas introduction means comprises at least one aeration gas inlet in the base section.
5. The valve defined in claim 4 wherein the aeration gas delivery means be adapted to deliver aeration gas to the or each inlet in the base section.
6. The valve defined in any one of the preceding claims wherein the base section is horizontal or angled.
7. A method of flow control of fluidisable solids by means of a non-mechanical valve comprising a pipe having a solids inlet and a solids outlet, the pipe comprising two upstanding legs and a base section connecting together lower ends of the legs, the method comprising:
(i) maintaining the valve flooded with solids;
(ii) injecting aeration gas into each leg to maintain solids flowing in the valve from the inlet to the outlet in a fluidised state; and (iii) controlling aeration gas injection into the legs to control the flow of solids through the valve.
(i) maintaining the valve flooded with solids;
(ii) injecting aeration gas into each leg to maintain solids flowing in the valve from the inlet to the outlet in a fluidised state; and (iii) controlling aeration gas injection into the legs to control the flow of solids through the valve.
8. The method defined in claim 7 wherein step (iii) comprises increasing or decreasing the flow of aeration gas into one leg compared with the other leg to control the flow of solids through the valve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPN2273A AUPN227395A0 (en) | 1995-04-07 | 1995-04-07 | A non-mechanical valve |
| AUPN2273 | 1995-04-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2217503A1 true CA2217503A1 (en) | 1996-10-10 |
Family
ID=3786625
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002217503A Abandoned CA2217503A1 (en) | 1995-04-07 | 1996-04-04 | A non-mechanical valve |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0819092A4 (en) |
| JP (1) | JPH11503099A (en) |
| KR (1) | KR19980703492A (en) |
| CN (1) | CN1181052A (en) |
| AR (1) | AR001572A1 (en) |
| AU (1) | AUPN227395A0 (en) |
| BR (1) | BR9604841A (en) |
| CA (1) | CA2217503A1 (en) |
| TW (1) | TW334506B (en) |
| WO (1) | WO1996031418A1 (en) |
| ZA (1) | ZA962796B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2161172B1 (en) * | 1999-10-22 | 2002-10-01 | Univ Madrid Complutense | PNEUMATIC DEVICE FOR CONTROLLING THE FLOW OF GRANULAR SOLIDS. |
| US8753044B2 (en) | 2008-06-09 | 2014-06-17 | Uop Llc | L-valve construction for controlling solids flow in a liquid medium using standard pipe fittings |
| CN107531430B (en) * | 2015-06-24 | 2020-07-28 | 环球油品公司 | Device for conveying catalyst |
| WO2017137392A1 (en) * | 2016-02-12 | 2017-08-17 | Reel Alesa Sas | Device and method for conveyance of powder materials in hyperdense phase |
| CN107606242B (en) * | 2017-09-20 | 2024-05-03 | 南京高正农用化工有限公司 | Pesticide granule air current sprays mixing control valve |
| CN109879057A (en) * | 2019-03-01 | 2019-06-14 | 成都瑞柯林工程技术有限公司 | Powder fluidization structure and device |
| US20220275287A1 (en) * | 2019-08-05 | 2022-09-01 | Sabic Global Technologies B.V. | Loop seal on reactor first stage dipleg to reduce hydrocarbon carryover to stripper for naphtha catalytic cracking |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2267965A1 (en) * | 1974-04-18 | 1975-11-14 | Guyot Jacques | Pneumatic conveyor for granular material - has accelerators along discharge line and aeration cap on silo base |
| FR2286682A1 (en) * | 1974-10-01 | 1976-04-30 | Bonvillain Et E Ronceray Ets | Elevator-cooler for dry foundry sand - which is conveyed by compressed air up water-cooled column and into a hopper |
| DE2657677C3 (en) * | 1976-12-20 | 1979-11-15 | Mittelmann Gmbh & Co Kg, 5928 Laasphe | Method and device for the pneumatic conveyance of bulk materials, viscous masses, sludge or the like. in a tubular conveyor trough |
| SE7707545L (en) * | 1977-06-29 | 1978-12-30 | Nordisk Fluidbeddforgasning Ha | DEVICE FOR ADJUSTABLE DISCHARGE OF A FLOOD OF PARTICULAR MATERIAL IN FLUIDIZED CONDITION THROUGH A DISCHARGE OPENING |
| DE4137853A1 (en) * | 1991-11-16 | 1993-05-19 | Babcock Energie Umwelt | METHOD AND DEVICE FOR DISCHARGING SOLIDS |
| JP2953229B2 (en) * | 1992-12-25 | 1999-09-27 | 日立プラント建設株式会社 | Low-speed high-concentration transport equipment |
-
1995
- 1995-04-07 AU AUPN2273A patent/AUPN227395A0/en not_active Abandoned
-
1996
- 1996-04-04 EP EP96907948A patent/EP0819092A4/en not_active Withdrawn
- 1996-04-04 CN CN96193096A patent/CN1181052A/en active Pending
- 1996-04-04 KR KR1019970706896A patent/KR19980703492A/en not_active Application Discontinuation
- 1996-04-04 JP JP8529793A patent/JPH11503099A/en active Pending
- 1996-04-04 BR BR9604841A patent/BR9604841A/en not_active Application Discontinuation
- 1996-04-04 WO PCT/AU1996/000196 patent/WO1996031418A1/en not_active Application Discontinuation
- 1996-04-04 CA CA002217503A patent/CA2217503A1/en not_active Abandoned
- 1996-04-09 AR AR33609596A patent/AR001572A1/en unknown
- 1996-04-09 ZA ZA962796A patent/ZA962796B/en unknown
- 1996-05-17 TW TW085105856A patent/TW334506B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| MX9707670A (en) | 1997-11-29 |
| JPH11503099A (en) | 1999-03-23 |
| BR9604841A (en) | 1998-06-16 |
| WO1996031418A1 (en) | 1996-10-10 |
| AUPN227395A0 (en) | 1995-05-04 |
| EP0819092A1 (en) | 1998-01-21 |
| KR19980703492A (en) | 1998-11-05 |
| CN1181052A (en) | 1998-05-06 |
| ZA962796B (en) | 1996-10-09 |
| TW334506B (en) | 1998-06-21 |
| EP0819092A4 (en) | 2001-01-24 |
| AR001572A1 (en) | 1997-11-26 |
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| FZDE | Discontinued |