CA1078559A - Smelt spout for recovery boiler - Google Patents
Smelt spout for recovery boilerInfo
- Publication number
- CA1078559A CA1078559A CA239,604A CA239604A CA1078559A CA 1078559 A CA1078559 A CA 1078559A CA 239604 A CA239604 A CA 239604A CA 1078559 A CA1078559 A CA 1078559A
- Authority
- CA
- Canada
- Prior art keywords
- spout
- trough
- smelt
- jet
- steam
- 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.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/12—Combustion of pulp liquors
- D21C11/122—Treatment, e.g. dissolution, of the smelt
Abstract
SMELT SPOUT FOR RECOVERY BOILER
ABSTRACT OF THE DISCLOSURE
A non water cooled smelt spout for a pulp mill chemical recovery furnace is disclosed. The spout is con-structed from insulating and refractory material contained in a metal trough and is provided with a steam jet immediately adjacent the bottom free end of the spout. The jet impairs the formation of slag on the bottom of the trough and disinte-grates the smelt stream issuing from the spout. Preferably the steam passage leading to the jet or nozzle extends along the bottom of the spout whereby the steam forming the jet also cools the bottom wall.
ABSTRACT OF THE DISCLOSURE
A non water cooled smelt spout for a pulp mill chemical recovery furnace is disclosed. The spout is con-structed from insulating and refractory material contained in a metal trough and is provided with a steam jet immediately adjacent the bottom free end of the spout. The jet impairs the formation of slag on the bottom of the trough and disinte-grates the smelt stream issuing from the spout. Preferably the steam passage leading to the jet or nozzle extends along the bottom of the spout whereby the steam forming the jet also cools the bottom wall.
Description
8~S~
\
The presen-t ~nvention relates to ~ ~melt spout ~or a recovexy boiler~ More spec~fically the presen~ invention 5 relat~s to a combination 9melt 5pOU~ and shat~ering s~eam ~ or a chemical recovery ~urnace such as those used to recover pulping cooking ~hemical from black liquox in the kraft process.
Recovery of chemical from blacX liquor in the kraft 10 pulping process normally require~ concentra~ing the used liguor (black liquor) and eeding the concentrated black liquor i~to, for example, a Tomlinson type furnace wherein the remainder of the water is evaporated and a char composed primarily of sodium sulphate, sodium carbonate and some 15 organics i5 formed. This char falls to the bed or hearth o the furnace whi~h is maintained under reducing conditions and at a temperature to form a smelt consisting essentially of molten sodium sulfide and sodium carbonate. The smelt pouxs out of the furnace on a smelt spout and is di~in-20 tegrated by impin~ing a steam jet onto the ~melt stream~o that the smelt enter3 the dis~olving tank as small particles and is dis~olved in water~
The smelt stream from the furnace is a~ about 1800 - 1900F and thus care must be taken to protect the 25 Spout BtruCtUre from overheating and melting or deter-iorat~ng in any way, since the furnace must be shut down if the spout has to be changed. Modern furnaces u~e what i~ ~nown a~ a water cooled spout which generally takes ~he form of a jacketed metal trough through which water i~
circulated to cool and prote~t it from the molten smelt.
Water eooling efectively permits a spout life normally over about a yea~, but it al~o provide~ a ~afety hazardO Contact between water and ~od.ium sulfide in the smelt in any appreciable quantity will result in an 35 explo~ion and extxeme care i~ taken not only in the area -- 2 ~ 3 .
s~
of the ~pout hut al~o within the urnace ~o en~ure ~hat water does no~ conkact the smelt. Wa~er cooling of the smelt æpout add~ a further source of water that may contact the smelt in the Purnace and cau~e explosions.
According to a repork oP the "Blac~ Liquor Recov~ry Boilex Advisory Committee" since 1968 there have been two explo~ions as direct result o water from the ~melt spout and Pive other non-explo6ive incident~
involving water leaking from the ~pout. Thus in ~pite oP the precautions taken explosions are caus~d by water e~caping from ~he cooling jacket of a water cooled spout.
As above indicated the ~melt after it leaves the spout is disintegrated by means of an impinging jet oP
steam or the like to reduce the size of the ~melt parti-cles contacting the liquid in the dis~olving tank, It ha~
been proposed for example in Canadian Patents 567,018 to d~rect the steam jet down onto the top of the stream of smelt leaving the spout.
It has been contemplated to utilize refractory material to insulate and isolate the metal of the spout ~rom the smelt, however, such attempts have not been parti-cularly successful. The spou~ life was ~enerally ~hort with failure occuring adjacent the ~ip or free end of the spout~
At the ~ip or free end of the smelt spout a so called slag i8 formed by solidification of the smelt. This solidified smelt or 81ag projects outwardly from the free end of the spout and eventually works its way around on to the bottom of the spout. It has been found that metal de-teriorate3 beneath the slag particularl~ on the bottom oP
the spout and it is at this point that ~ailure Pi~t occurs.
The present invention eliminate~ the necessity Por wa~er cooling and utilize~ the ~team ~et, not only to disintegrate the smelt stream but al~o to prolong the life _ _ _ _ _ . ., .. ,, . . _ . . ., .. . . ., ........................ . .. _ .` ' ' ' ` `' ' ' ' ' ' ' .
~)78~
of the ~melt ~poutO
Broadly the present invention relates a sm01t~pout compri~ing a metal trough having bottom and side wall~ a lining in said trough i~olating 3aid ~melt frsm said trough~ a weir formed at the free or front end o~
said trough, a steam jet means positioned immediately adjacent said bottom wall and direeting steam away from said spout to inter~ect the trajectory of ~mel~ pouring from said spout and disintegrate ~aid smelt.
Preferably said steam jet is connected with a ~team chamber po~itioned on the out~ide of said bottom wall where~y 3team for said jet pas~e~ ~hrough said chamber and cool~ said bottom wall.
Further features, objects and advantage~ will be evident from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings in which Figure 1 i8 a plan view o~ a metal trough for the spout of the pxesent invention.
Figure 2 i~ a ~ide view of the trough of Figur~
1.
Figure 3 i5 an end view from the free end of the trough of Figures 1 and 2, and Figure ~ is a 3ection through the spout of the >
pre~ent invention formed using the trough illustrated i~
Figure~ 1, 2 and 3.
Ref~rring to Figures 1, 2 and 3 the trough ~0 in which the ~pout of the present invention i6 formed ha~ a bottom wall 12, a pair of side walls 14 and 16 extending upwardly at an obtuse angle from the opposite side~ o~ the bottom 12 and a plate 18 extendinq acro~s the free end o~
the trough 10 to form the weir 20 ovcr which the ~melt pour8.
Suitable f lange~ 22 are provided on the f~xed end o~ the trough 22 for anchoring the trough to the furnace structure.
~ 4 -, 1C~78~5~
Mounted on the botkom plate 12 ~dj~cent the free end formed b~ the plate 18 i~ a nozzle 24 whlch dir~ct~ steam outwardly from ~he free end o~ the trough. Thi~ nozzle 24 is connected via a passage 26 Isee Figures 1 and 4) ex-tending along the bottom plate 12 and communicating with a manifold 28 having an inlet nipple 30 that may be connected to a suitàble source of pres~urized steam (no~ shawn)L
The trough lO i5 used to con~tnlck a spout 50. Ag ~hown irl Figure 4 the ~abrica~ed spout 50 has a layer of in-sulating brick 32 and a layer of plastic refractory material 34 8uitably contoured to ob~aln a desired slope for pouring of the ~melt 36 out the spout 50.
In operation smelt is indicated at 36 in Figure 4 pours d~wn ~he ~pout 50 and issue~ over the weir 20 formed in the wall 18 to form a stream 38 of smel~. Steam i6 in-jected into the chamber 28 via the inlet 30 and passes via pa~sage 26 to issue 'chrough the noæzle 24 as a jet o steam 40 which intercepts the trajectsry of the ~tream 38 and disintegrate~ the smelt into small particles that fall into the watQr in ~he dissolv$ng tank without creating a major explosion.
It will be noted that the nozzle 24 is po~itioned immediately ~djacent the bottom 12 of the spout 50 and thus prevents any s lag or the lik~ from accumulating on the front wall 18 and running d~wn on to the bottom wall 12 at least in the area of the jet 40. This reduction in slag build up on the bottom wall 12 help~ to prolong the life of the 5pout.
Ths passage 26 require~ that the steam flow in very clo~e proximity to the bottom plate 12. The length o this passage combined with the length of th~ chamber or mani~old 28 in a longitudinal direction o~ the ~pout pr~vides time ~or ~h~ ~team to contact and cool the bo~tom plate 12.
_ 5 ... _ .. _ , .. . . .
. .
7~55~
.. , It will be appxeciated that the pla~e 18 and the trough 10 will be warmer wi~h the present invention ~han when water cooled spout is u3ed. It is believed ~his higher temperature has a beneficial effect as it has been ex-perienced that the slag is much easier to dislodge than with a wa~er cooled spout.
As above indicat~d the length of ~he pa~sage 26 or combined length of the passag~ 26 and the Chamber 28, may be adjusted to obtain the desired degree of cooling.
It has been found that for a spou~ approximately thre~
~eet long the passage 26 should be about 8 inche~ long and the chamber 28 about 6 inches long and for a bot~om plate 12 about 8 inches wide~ the pas~age Z6 should be about 5 inches wide. Obviously the wid~h of the passage also effects the cooling. Preferably the slope of the plate 12 and thus direction of the steam jet 40 will be downward at about 20.
As above indicated the lengths of the passage 26 and chamber 28 may vary as required to obtain a desired degree of cooling but if no cooling is nece~sa~y obvîously the chamber 28 and ~he passage 26 will be as small as possible it being important that the nozzle 26 he position~d 25 immediately adjac~nt the bottom 12 o the spout 50 to ensure there is a minimum build up of slag on the bottom plate.
Modification~ will be evident to those skilled in the art without departing from the spixit of the inve~tion as defined in the apparsnt claim~.
\
The presen-t ~nvention relates to ~ ~melt spout ~or a recovexy boiler~ More spec~fically the presen~ invention 5 relat~s to a combination 9melt 5pOU~ and shat~ering s~eam ~ or a chemical recovery ~urnace such as those used to recover pulping cooking ~hemical from black liquox in the kraft process.
Recovery of chemical from blacX liquor in the kraft 10 pulping process normally require~ concentra~ing the used liguor (black liquor) and eeding the concentrated black liquor i~to, for example, a Tomlinson type furnace wherein the remainder of the water is evaporated and a char composed primarily of sodium sulphate, sodium carbonate and some 15 organics i5 formed. This char falls to the bed or hearth o the furnace whi~h is maintained under reducing conditions and at a temperature to form a smelt consisting essentially of molten sodium sulfide and sodium carbonate. The smelt pouxs out of the furnace on a smelt spout and is di~in-20 tegrated by impin~ing a steam jet onto the ~melt stream~o that the smelt enter3 the dis~olving tank as small particles and is dis~olved in water~
The smelt stream from the furnace is a~ about 1800 - 1900F and thus care must be taken to protect the 25 Spout BtruCtUre from overheating and melting or deter-iorat~ng in any way, since the furnace must be shut down if the spout has to be changed. Modern furnaces u~e what i~ ~nown a~ a water cooled spout which generally takes ~he form of a jacketed metal trough through which water i~
circulated to cool and prote~t it from the molten smelt.
Water eooling efectively permits a spout life normally over about a yea~, but it al~o provide~ a ~afety hazardO Contact between water and ~od.ium sulfide in the smelt in any appreciable quantity will result in an 35 explo~ion and extxeme care i~ taken not only in the area -- 2 ~ 3 .
s~
of the ~pout hut al~o within the urnace ~o en~ure ~hat water does no~ conkact the smelt. Wa~er cooling of the smelt æpout add~ a further source of water that may contact the smelt in the Purnace and cau~e explosions.
According to a repork oP the "Blac~ Liquor Recov~ry Boilex Advisory Committee" since 1968 there have been two explo~ions as direct result o water from the ~melt spout and Pive other non-explo6ive incident~
involving water leaking from the ~pout. Thus in ~pite oP the precautions taken explosions are caus~d by water e~caping from ~he cooling jacket of a water cooled spout.
As above indicated the ~melt after it leaves the spout is disintegrated by means of an impinging jet oP
steam or the like to reduce the size of the ~melt parti-cles contacting the liquid in the dis~olving tank, It ha~
been proposed for example in Canadian Patents 567,018 to d~rect the steam jet down onto the top of the stream of smelt leaving the spout.
It has been contemplated to utilize refractory material to insulate and isolate the metal of the spout ~rom the smelt, however, such attempts have not been parti-cularly successful. The spou~ life was ~enerally ~hort with failure occuring adjacent the ~ip or free end of the spout~
At the ~ip or free end of the smelt spout a so called slag i8 formed by solidification of the smelt. This solidified smelt or 81ag projects outwardly from the free end of the spout and eventually works its way around on to the bottom of the spout. It has been found that metal de-teriorate3 beneath the slag particularl~ on the bottom oP
the spout and it is at this point that ~ailure Pi~t occurs.
The present invention eliminate~ the necessity Por wa~er cooling and utilize~ the ~team ~et, not only to disintegrate the smelt stream but al~o to prolong the life _ _ _ _ _ . ., .. ,, . . _ . . ., .. . . ., ........................ . .. _ .` ' ' ' ` `' ' ' ' ' ' ' .
~)78~
of the ~melt ~poutO
Broadly the present invention relates a sm01t~pout compri~ing a metal trough having bottom and side wall~ a lining in said trough i~olating 3aid ~melt frsm said trough~ a weir formed at the free or front end o~
said trough, a steam jet means positioned immediately adjacent said bottom wall and direeting steam away from said spout to inter~ect the trajectory of ~mel~ pouring from said spout and disintegrate ~aid smelt.
Preferably said steam jet is connected with a ~team chamber po~itioned on the out~ide of said bottom wall where~y 3team for said jet pas~e~ ~hrough said chamber and cool~ said bottom wall.
Further features, objects and advantage~ will be evident from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings in which Figure 1 i8 a plan view o~ a metal trough for the spout of the pxesent invention.
Figure 2 i~ a ~ide view of the trough of Figur~
1.
Figure 3 i5 an end view from the free end of the trough of Figures 1 and 2, and Figure ~ is a 3ection through the spout of the >
pre~ent invention formed using the trough illustrated i~
Figure~ 1, 2 and 3.
Ref~rring to Figures 1, 2 and 3 the trough ~0 in which the ~pout of the present invention i6 formed ha~ a bottom wall 12, a pair of side walls 14 and 16 extending upwardly at an obtuse angle from the opposite side~ o~ the bottom 12 and a plate 18 extendinq acro~s the free end o~
the trough 10 to form the weir 20 ovcr which the ~melt pour8.
Suitable f lange~ 22 are provided on the f~xed end o~ the trough 22 for anchoring the trough to the furnace structure.
~ 4 -, 1C~78~5~
Mounted on the botkom plate 12 ~dj~cent the free end formed b~ the plate 18 i~ a nozzle 24 whlch dir~ct~ steam outwardly from ~he free end o~ the trough. Thi~ nozzle 24 is connected via a passage 26 Isee Figures 1 and 4) ex-tending along the bottom plate 12 and communicating with a manifold 28 having an inlet nipple 30 that may be connected to a suitàble source of pres~urized steam (no~ shawn)L
The trough lO i5 used to con~tnlck a spout 50. Ag ~hown irl Figure 4 the ~abrica~ed spout 50 has a layer of in-sulating brick 32 and a layer of plastic refractory material 34 8uitably contoured to ob~aln a desired slope for pouring of the ~melt 36 out the spout 50.
In operation smelt is indicated at 36 in Figure 4 pours d~wn ~he ~pout 50 and issue~ over the weir 20 formed in the wall 18 to form a stream 38 of smel~. Steam i6 in-jected into the chamber 28 via the inlet 30 and passes via pa~sage 26 to issue 'chrough the noæzle 24 as a jet o steam 40 which intercepts the trajectsry of the ~tream 38 and disintegrate~ the smelt into small particles that fall into the watQr in ~he dissolv$ng tank without creating a major explosion.
It will be noted that the nozzle 24 is po~itioned immediately ~djacent the bottom 12 of the spout 50 and thus prevents any s lag or the lik~ from accumulating on the front wall 18 and running d~wn on to the bottom wall 12 at least in the area of the jet 40. This reduction in slag build up on the bottom wall 12 help~ to prolong the life of the 5pout.
Ths passage 26 require~ that the steam flow in very clo~e proximity to the bottom plate 12. The length o this passage combined with the length of th~ chamber or mani~old 28 in a longitudinal direction o~ the ~pout pr~vides time ~or ~h~ ~team to contact and cool the bo~tom plate 12.
_ 5 ... _ .. _ , .. . . .
. .
7~55~
.. , It will be appxeciated that the pla~e 18 and the trough 10 will be warmer wi~h the present invention ~han when water cooled spout is u3ed. It is believed ~his higher temperature has a beneficial effect as it has been ex-perienced that the slag is much easier to dislodge than with a wa~er cooled spout.
As above indicat~d the length of ~he pa~sage 26 or combined length of the passag~ 26 and the Chamber 28, may be adjusted to obtain the desired degree of cooling.
It has been found that for a spou~ approximately thre~
~eet long the passage 26 should be about 8 inche~ long and the chamber 28 about 6 inches long and for a bot~om plate 12 about 8 inches wide~ the pas~age Z6 should be about 5 inches wide. Obviously the wid~h of the passage also effects the cooling. Preferably the slope of the plate 12 and thus direction of the steam jet 40 will be downward at about 20.
As above indicated the lengths of the passage 26 and chamber 28 may vary as required to obtain a desired degree of cooling but if no cooling is nece~sa~y obvîously the chamber 28 and ~he passage 26 will be as small as possible it being important that the nozzle 26 he position~d 25 immediately adjac~nt the bottom 12 o the spout 50 to ensure there is a minimum build up of slag on the bottom plate.
Modification~ will be evident to those skilled in the art without departing from the spixit of the inve~tion as defined in the apparsnt claim~.
Claims (2)
1. A smelt spout for a paper pulp mill chemical recovery furnace, said spout comprising a metal trough having a bottom wall, a refractory lining in said trough, means for connecting said trough to said furnace at one end of said trough, said trough at the end opposite said one end terminating in a free end from which a smelt stream flows, nozzle means immediately adjacent to the bottom of said trough and said free end of said trough, means for directing steam to said nozzle means, said nozzle means forming a steam jet intersecting the trajectory of said stream of smelt flowing from said spout thereby to disintegrate said stream, said nozzle means being positioned relative to said trough means so that said jet passes immediately adjacent said bottom wall at said free end and impairs the build up of slag formed by solidification of said smelt onto said bottom wall adjacent said free end.
2. A smelt spout as defined in claim 1 wherein said steam supply means comprises a passage in heat transfer relation-ship with said bottom wall of said trough whereby said steam forming said jet and passing through said passage cools said bottom wall.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA239,604A CA1078559A (en) | 1975-11-10 | 1975-11-10 | Smelt spout for recovery boiler |
| SE7612328A SE7612328L (en) | 1975-11-10 | 1976-11-04 | MELTING GRAIN FOR RECYCLING BOILERS |
| FI763205A FI60894C (en) | 1975-11-10 | 1976-11-09 | SMAELTRAENNA FOER EN KEMIKALIE AOTERVINNINGSUGN |
| JP13511276A JPS5284857A (en) | 1975-11-10 | 1976-11-10 | Melted material discharging passage for reboiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA239,604A CA1078559A (en) | 1975-11-10 | 1975-11-10 | Smelt spout for recovery boiler |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078559A true CA1078559A (en) | 1980-06-03 |
Family
ID=4104515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,604A Expired CA1078559A (en) | 1975-11-10 | 1975-11-10 | Smelt spout for recovery boiler |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5284857A (en) |
| CA (1) | CA1078559A (en) |
| FI (1) | FI60894C (en) |
| SE (1) | SE7612328L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8152965B2 (en) | 2006-10-18 | 2012-04-10 | Boildec Oy | Method and device for emptying the floor of a soda recovery boiler |
| US8808461B2 (en) | 2008-12-05 | 2014-08-19 | Boildec Oy | Method and device for emptying the floor of a black liquor recovery boiler |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0623597Y2 (en) * | 1988-01-18 | 1994-06-22 | 三菱重工業株式会社 | Smelt spout device |
-
1975
- 1975-11-10 CA CA239,604A patent/CA1078559A/en not_active Expired
-
1976
- 1976-11-04 SE SE7612328A patent/SE7612328L/en not_active Application Discontinuation
- 1976-11-09 FI FI763205A patent/FI60894C/en not_active IP Right Cessation
- 1976-11-10 JP JP13511276A patent/JPS5284857A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8152965B2 (en) | 2006-10-18 | 2012-04-10 | Boildec Oy | Method and device for emptying the floor of a soda recovery boiler |
| US8808461B2 (en) | 2008-12-05 | 2014-08-19 | Boildec Oy | Method and device for emptying the floor of a black liquor recovery boiler |
Also Published As
| Publication number | Publication date |
|---|---|
| FI60894B (en) | 1981-12-31 |
| JPS5284857A (en) | 1977-07-14 |
| FI763205A (en) | 1977-05-11 |
| SE7612328L (en) | 1977-05-11 |
| FI60894C (en) | 1982-04-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |