US3314399A - Apparatus - Google Patents

Apparatus Download PDF

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Publication number
US3314399A
US3314399A US507750A US50775065A US3314399A US 3314399 A US3314399 A US 3314399A US 507750 A US507750 A US 507750A US 50775065 A US50775065 A US 50775065A US 3314399 A US3314399 A US 3314399A
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US
United States
Prior art keywords
furnace
zone
hearth
liquor
combustion zone
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 - Lifetime
Application number
US507750A
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English (en)
Inventor
Adolf W Gessner
Theodore J Kayhart
Gordon L Dibble
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lummus Technology LLC
Original Assignee
Lummus Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Lummus Co filed Critical Lummus Co
Priority to US507750A priority Critical patent/US3314399A/en
Priority to SE15543/66A priority patent/SE308858B/xx
Application granted granted Critical
Publication of US3314399A publication Critical patent/US3314399A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • This invention relates generally to recovery furnaces and, more particularly to a pulping liquor recovery furnace for high sulfur reduction.
  • the percentage suliidity of the cooking liquor is found to be from 50% to 90%, greater than in a conventional kraft liquor (percentage suliidity being equal to 100 (Na2S)/ (NaZS-l-NaOH-l-NazCOa), all quantities being expressed in moles).
  • the alkali-to-wood ratio employed within the digester is greater than the ratio used in the conventional cooking. This larger ratio causes a larger amount of sulfur Per unit of liquor burned to circulate through the recovery furnace.
  • FIGURE 1 is a schematic diagram, in section, of a pulping liquor recovery furnace in which one embodiment of the present invention is included;
  • FIGURE 2 is a cross-section taken along lines 2--2 of FIGURE l;
  • FIGURE 3 is a cross-section taken along lines 3 3 of FIGURE 1.
  • the present invention comprises two modifications of a conventional recovery furnace.
  • the first modification is that a refractory obstacle is placed above the hearth zone thereby reducing the net radiation flow and causing additional heat to be available for the sulfur reduction.
  • the second modification is that the boiler tubing which normally su-rrounds the hearth zone in a kraft recovery furnace is removed.
  • a refractory-lined recovery furnace is generally indicated at 1.
  • the black liquor enters furnace 1 through inlet tubes 2 and 3 located part way up the sides of furnace 1.
  • Primary air travels through inlet tubes 4 and 5 and is injected into a hearth zone, generally shown as 6.
  • the inlet tubes 2 and 3 inject the black liquor into a secondary combustion zone, generally denoted as 7, also into which secondary air may be introduced through a tube attached to aperture 8.
  • a refractory battle 14 has been provided near tubes 11 to assist in the heating of the water.
  • the inherent heat of the black liquor causes decomposition of the lignin and vaporization of the water.
  • the black liquor travels into hearth zone 6 in which the sulfur reduction reactions occur.
  • the resulting smelt accumulates ⁇ at the bottom of furnace 1 in a layer 15 and is withdrawn from layer 15 through an outlet tube 16.
  • the present invention changes the structure of the foregoing conventional recovery furnace 1 by irst omitting the boiler tubes which would normally surround hearth zone 6.
  • the temperature difference between the boiler tubes and a hearth zone of the conventional furnaces causes heat to ow from said hotter hearth zone to said cooler boiler tubes.
  • the heat normally lost thereto from hearth zone 6 is retained and is utilized in the endothermic reduction of the sultes, thiosulfates and sulfates to sulfide.
  • the second modification is that below inlet tubes 2 and 3 and Aabove inlet tubes 4 and 5, radiation baflies 17, 18 and 19 have been inserted. Bales 17 and 18 extend downward from the sides of furnace 1.
  • Baffie 19 has the shape of an inverted V, the apex of which is placed in the open space between baffles 17 and 13. Additional support for batiies 17 and 18 may be provided by a plurality of support means 20 and 21 positioned like a brace between said balies 17 and 18 and the walls of furnace 1. Baffles 17 and 18 extend horizontally to a point further toward the center of furnace 1 than are the ends of bafe 19, so :that in viewing furnace 1 from the top, the ends of articless 17 and 19 and the ends of baffles 18 and 19 appear t-o overlap.
  • baiiies 17, '18 and 19 could be replaced by lany obstacle which would effectively block the line of sight between hearth Zone 6 and secondary coubustion zone 7.
  • baffles or some other obstacle are used, they must be shaped so as not to trap the black liquor traveling between secondary combustion zone 7 and hearth zone 6, and so as not to obstruct inlet tubes 2 and 3.
  • the batiies or obstacles may be made a par-t of the internal furnace construction to increase their ability to withstand operational stresses and strains.
  • Baifles 17, 18 and 19 are constructed out of a refractory material such that they can attain a temperature up to about 2300 F.
  • the construction of the downward slanting baiiies 17 and 18 and the inverted V of bafe L19 causes most of the heat radiated upward from hearth zone 6 to be reected back into hearth zone 6, thereby preventing said radiated heat from seeking out the cooler, upper parts of furnace 1.
  • the heat released in hearth zone 6 is thereby available for the endothermic reduction reactions, while the heat released in secondary combustion zone 7 performs the functions of evaporating water in the black liquor, charring the lignin in the black liquor, and vaporizing the water in tubes 1-1 and mud drum 112.
  • the hot gases pass to a conduit 24 for transmission of the .gases to other recovery operations and eventual venting. s
  • bafhes x17 and 18 over bafhe 19 are illustrated in FIGURE 2, and the construction of bathe 19 is illustrated in FIGURE 3.
  • suppport frame 22 extends to the walls of the furnace and supports the refractory lining 23.
  • Structural steel members in this structure are water cooled to maintainrnechanical strength.
  • a blackliquor recovery furnace comprising:
  • the furnace of claim 1 further comprising a heat recovery means located in the upper portion of said secondary combustion zone.
  • a black-liquor recovery furnace comprising:
  • a housing including a secondary combustion chamber and a hearth combustion chamber
  • a black-liquor recovery furnace comprising:
  • furnace housing having an upper, secondary combustion zone and a lower, hearth combustion zone
  • bathe means separating said upper and lower zones but allowing huid flow therebetween, said bathe means comprising rst baihes extending from the sides of said housing and a second, central bathe at a slightly different level, said first and second bathes presenting downwardly-sloping surfaces to downwardly-flowing huid;
  • outlet means communicating with said lower zone in the hearth region thereof;
  • outlet means positioned so as to remove combustion gases after passage through said recovery means.

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US507750A 1965-11-15 1965-11-15 Apparatus Expired - Lifetime US3314399A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US507750A US3314399A (en) 1965-11-15 1965-11-15 Apparatus
SE15543/66A SE308858B (https=) 1965-11-15 1966-11-14

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US507750A US3314399A (en) 1965-11-15 1965-11-15 Apparatus

Publications (1)

Publication Number Publication Date
US3314399A true US3314399A (en) 1967-04-18

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Application Number Title Priority Date Filing Date
US507750A Expired - Lifetime US3314399A (en) 1965-11-15 1965-11-15 Apparatus

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US (1) US3314399A (https=)
SE (1) SE308858B (https=)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US620752A (en) * 1899-03-07 Feldt
US1794006A (en) * 1929-09-24 1931-02-24 Edge Moor Iron Company Recovery apparatus
GB548873A (en) * 1940-07-27 1942-10-28 Babcock & Wilcox Ltd Improvements in or relating to tubulous boiler plant
US2591188A (en) * 1946-11-25 1952-04-01 Nilsson Nils Enok Apparatus for recovering the inorganic content of concentrated waste liquor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US620752A (en) * 1899-03-07 Feldt
US1794006A (en) * 1929-09-24 1931-02-24 Edge Moor Iron Company Recovery apparatus
GB548873A (en) * 1940-07-27 1942-10-28 Babcock & Wilcox Ltd Improvements in or relating to tubulous boiler plant
US2591188A (en) * 1946-11-25 1952-04-01 Nilsson Nils Enok Apparatus for recovering the inorganic content of concentrated waste liquor

Also Published As

Publication number Publication date
SE308858B (https=) 1969-02-24

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