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EP0660896A1 - Procede de recuperation de produits chimiques et d'energie a partir de bains epuises - Google Patents

Procede de recuperation de produits chimiques et d'energie a partir de bains epuises

Info

Publication number
EP0660896A1
EP0660896A1 EP92915696A EP92915696A EP0660896A1 EP 0660896 A1 EP0660896 A1 EP 0660896A1 EP 92915696 A EP92915696 A EP 92915696A EP 92915696 A EP92915696 A EP 92915696A EP 0660896 A1 EP0660896 A1 EP 0660896A1
Authority
EP
European Patent Office
Prior art keywords
gas
particles
reactor
process according
temperature
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.)
Withdrawn
Application number
EP92915696A
Other languages
German (de)
English (en)
Inventor
Jan-Erik Kignell
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.)
Chemrec AB
Original Assignee
Chemrec AB
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 Chemrec AB filed Critical Chemrec AB
Publication of EP0660896A1 publication Critical patent/EP0660896A1/fr
Withdrawn legal-status Critical Current

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
    • D21C11/125—Decomposition of the pulp liquors in reducing atmosphere or in the absence of oxidants, i.e. gasification or pyrolysis
    • 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
    • D21C11/06—Treatment of pulp gases; Recovery of the heat content of the gases; Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds
    • D21C11/063—Treatment of gas streams comprising solid matter, e.g. the ashes resulting from the combustion of black liquor
    • D21C11/066—Separation of solid compounds from these gases; further treatment of recovered products
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/12—Heat utilisation in combustion or incineration of waste

Definitions

  • the present invention relates to a process for the extraction of chemicals and energy from cellulose spent liquors, primarily for the extraction of chemicals and energy from the gas stream from a reactor for black liquor gasification.
  • the recovery process comprises a heating stage, a reactor, where the organic molecular chains are broken down by pyrolysis and incineration to energy-rich gas and the inorganic content mainly forms finely divided particles of chemical melt which can be recovered.
  • the pyrolysis in combination with the incineration thus liberates heat energy, usually the temperature is about 1000°C in the reactor, and produces a combustible gas. It is desirable to extract the liberated heat and also exploit the combustible gas by means of further incineration.
  • SE-B-448 173 describes a method for the recovery of chemicals and energy from black liquor. According to SE-B-448 173 it has been possible to recover the sensible heat in the gas and simultaneously avoid settling problems by means of directly allowing the gases to pass through a liquid bath. Besides the melt particles being taken up by the said liquid, which is green liquor, the gas is simultaneously cooled. The gas which leaves the liquid bath and which has been freed from melt particles thereby achieves a temperature which in an unpressurised system only amounts to the order of 80°- 90°C, which also corresponds to the approximate temperature in the green liquor bath. Thus, in this unpressurised system, a melt-free gas flow is obtained at about 90°C, as is a liquid bath, consisting of green liquor, at about 90°C. Even if the process according to SE-B-448 173 is carried out at as high a pressure as 150 bar, heat recovery can at best take place by the generation of 300°C saturated steam.
  • the gas is cooled down to a temperature in the region of 100-300°C, which limits the possibility for efficient energy recovery. It is evident from the,above reasoning that it would be desirable to be able to extract the heat at a higher temperature, so that it can be recovered in the form of superheated steam.
  • a process is previously known from SE-B-182 336 for the extraction of chemicals and energy from cellulose spent liquors, preferably black liquor obtained in the sulphate cellulose process, wherein the spent liquor is conducted into a gasification reactor (1) for pyrolysis and partial incineration, wherein an energy-rich gas is formed containing particles of inorganic chemical melt, the said gas mixture is conveyed out of the reactor (1) and is thereby cooled by injection of a finely-divided cooling medium (cold gas) , in connection with departure from the reactor (1) , the said mixture of gas and non-adhesive chemical particles is conducted from a cooling chamber (2) , arranged in connection with the ' gasification reactor (1) , where they have at least partially solidified and been transformed into solid phase, so that the particles included in the gas mixture become non-adhesive, and thence to a separating arrangement (3) , preferably a cyclone, where the non-adhesive chemical particles are separated from the gas, the gas stream, which has been essentially cleaned
  • a first object of the invention is thus to offer a process and an arrangement whereby it is possible to make use of the heat from a gas stream containing both melt particles and gas, without drastically lowering the temperature level of the gas before the heat exchange takes place, at the same time as settling problems are avoided.
  • An additional object of the invention is to solve this in an optimal manner, in connection with application to gas turbines and in relation to the use of a cooling or scrubbing medium.
  • the abovementioned objects are achieved by the melt particles, which leave the reactor in the gas mixture, being cooled to a temperature not exceeding 700°C and the said finely-divided cooling medium being composed of water, together with the gas being washed after the heat exchange by being conducted through a washing arrangement (5) , a so-called wet scrubber (5) , for the washing out of remaining chemicals in solid form and gas form and by the separated solidified melt particles, which are removed at the bottom (31) of the separating arrangement (3) , being conducted to a receptacle (6) in which the particles are dissolved, wherein at least parts of the alkaline solution formed in this way are exploited for washing the gas in the said wet scrubber (5) .
  • a reactor 1 is shown to which is conducted black liquor via a first conduit 10 and air via a second conduit 11.
  • the black liquor is gasified by pyrolysis and partial incineration and thereby forms a gas/melt mixture, where the melt drops are present in finely suspended form, at a tempera- ture of about 1000°C.
  • a number of combustible gases are formed such as H 2 , CO, CH 4 , etc.
  • the melt particles contain mainly Na 2 C0 3 and NaS.
  • a cooling chamber 2 is arranged inside which are dis ⁇ tributed a number of spray nozzles 14 which are fed with water and/or cooled gas via conduits 15. With the aid of the nozzles 14 the water and/or gas is finely divided and comes into contact with the hot exhaust gases from the reactor 1. Thereby the exhaust gases are cooled to a temperature of about 650°C. This cooling results in the melt particles being converted into solid phase and thereby becoming non-adhesive. From the cooling chamber 2, which is located in connection with the reactor 1, the gas is conducted with its content of solidified chemical particles onwards through a conduit 4 which leads to a cyclone separator 3.
  • the solid and non-adhesive particles are separated from the gas and the gas leaves the cyclone via an upper conduit 30 while the crystalline particles are taken out through a lower conduit 31.
  • the gas phase in the conduit 30 still retains a temperature of about 650°C and is conducted in direct connection thereto into a heat exchanger unit 7 for the generation of superheated steam. Due to the purity of the gas, heat exchange can now take place without interfering deposition on the convection surfaces in the heat ex ⁇ changer.
  • the heat exchanger unit 7 comprises preferably a steam dome 70, a first heat exchanger core 71 for feed water which leads to the steam dome 70, a second coil 72 for production of saturated steam which leads back to the steam dome 70 and a third heat exchanger core 73 for generation of superheated steam, with a temperature of 300-600°C and a pressure of 20-150 bar, which is taken out via a conduit 74, preferably for the generation of electrical energy in a steam turbine according to the back pressure or condensing procedure.
  • This washing arrangement comprises a cylindrical casing 51 to which at a first level 52 is brought an alkaline solution by means of the spray nozzles in order to eliminate remaining chemicals from the gas, primarily H 2 S.
  • This alkaline solution can be obtained partly via a recirculating conduit 53 and partly from a receptacle 6.
  • this re ⁇ eptacle 6 contains green liquor which has been prepared by dissolving the chemicals that were separated off in the cyclone 3 in water or so-called weak liquor. This green liquor has thus been obtained by dissolution of the chemical particles that were recovered from the separator 3.
  • the liquor from the last-named receptacle 6 like that from the washer 5 is led away in conduits 60 and 55 for collection in receptacles (not shown) and for further processing in a causticisation stage for the production of white liquor which is reused in the digestion process.
  • the gas which is led away via a conduit 56 at the top of the gas washer 5 is exploited for the production of steam and/or electricity via gas and/or steam turbines.
  • the steam which is produced in the super ⁇ heated section can have a variable temperature preferably between 400°-600°C and the pressure can vary within a wide range up to about 160 bar.
  • the heat of the gas can be used to produce preheated air for the reactor.
  • the gas temperature after the boiler can also be varied, suitably within the range 150°-300°C.
  • the gas that is taken out of the top of the separator has in the preferred case a temperature of 500°-700°C.
  • the temperature in the reactor is suitably above 800°C and can reach up to 1500°C.
  • a preferred range is however 800°-1300°C. Neither is the invention limited to a reactor with an outlet at the lower end of the reactor, which in certain cases can create problems (in particular deposition problems) if the size of the melt particles varies widely.
  • a reactor with an upper outlet preferably a reactor of the Kopper-Totzek type, resulting in larger melt particles being collected in a melt bath at the bottom of the reactor and the melt particles departing from the reactor with the gas stream being guaranteed to have a relatively small and therefore a relatively uniform size, and thereby to ensure that all departing particles are cooled to a temperature below the solidification temperature.
  • a filter appropriately a textile filter, can be used.

Landscapes

  • Engine Equipment That Uses Special Cycles (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Industrial Gases (AREA)

Abstract

L'invention se rapporte à un procédé servant à l'extraction de produits chimiques et d'énergie à partir de bains épuisés de cellulose, de préférence la liqueur noire obtenue dans le traitement de la cellulose au sulfate, dans lequel on introduit le bain épuisé dans un réacteur de gazéification (1), afin d'effectuer une pyrolyse et une incinération partielle; on obtient, de ce fait, un gaz riche en énergie et contenant des particules de fusion chimiques inorganiques; ledit mélange de gaz est évacué du réacteur (1) et refroidi, de façon concomitante, par l'injection d'un milieu de refroidissement finement divisé, de préférence de l'eau, simultanément au départ du réacteur (1); ledit mélange de gaz et les particules chimiques non adhésives sont conduits depuis une chambre de refroidissement (2) reliée au réacteur de gazéification (1) vers un dispositif de séparation (3), de préférence un cyclone, où les particules chimiques non adhésives sont séparées du gaz; le flux de gaz, sensiblement épuré de particules chimiques, est extrait par l'intermédiaire d'une conduite supérieure située sur le dispositif de séparation (3), tandis que les particules chimiques sont extraites par l'intermédiaire d'une conduite inférieure située sur le dispositif de séparation (3), de ce fait, les particules fondues quittant le réacteur dans le mélange de gaz sont refroidies à une température où elles se sont solidifiées au moins partiellement et converties en phase solide, de façon que lesdites particules inclues dans le mélange de gaz sont non adhésives et qu'un échange thermique ultérieur du gaz séparé s'effectue à partir d'un niveau de température sensiblement préservé.
EP92915696A 1991-07-16 1992-06-29 Procede de recuperation de produits chimiques et d'energie a partir de bains epuises Withdrawn EP0660896A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9102186A SE470066B (sv) 1991-07-16 1991-07-16 Utvinning av kemikalier och energi från cellulosaavlutar genom förgasning
SE9102186 1991-07-16
PCT/SE1992/000477 WO1993002249A1 (fr) 1991-07-16 1992-06-29 Procede de recuperation de produits chimiques et d'energie a partir de bains epuises

Publications (1)

Publication Number Publication Date
EP0660896A1 true EP0660896A1 (fr) 1995-07-05

Family

ID=20383335

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92915696A Withdrawn EP0660896A1 (fr) 1991-07-16 1992-06-29 Procede de recuperation de produits chimiques et d'energie a partir de bains epuises

Country Status (9)

Country Link
EP (1) EP0660896A1 (fr)
JP (1) JPH07500150A (fr)
AU (1) AU655063B2 (fr)
BR (1) BR9206271A (fr)
CA (1) CA2112563A1 (fr)
FI (1) FI940145A0 (fr)
NO (1) NO940149D0 (fr)
SE (1) SE470066B (fr)
WO (1) WO1993002249A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE500263C2 (sv) * 1993-03-11 1994-05-24 Chemrec Ab Process för separation av svavelföreningar ur en koldioxid- och vätesulfidinnehållande gasström
TW245651B (en) * 1994-02-24 1995-04-21 Babcock & Wilcox Co Black liquor gasifier
SE505249C2 (sv) * 1994-11-04 1997-07-21 Kvaerner Pulping Tech Återvinning av blekerifiltrat genom att filtratet används i ett gaskylsystem i en förgasningsanläggning
DE19642162A1 (de) * 1996-10-12 1998-04-16 Krc Umwelttechnik Gmbh Verfahren zur Regeneration einer beim Kraftprozeß zum Aufschluß von Holz anfallenden Flüssigkeit unter gleichzeitiger Gewinnung von Energie
DE19718131C2 (de) * 1997-04-29 1999-10-14 Krc Umwelttechnik Gmbh Verfahren und Vorrichtung zur Regeneration einer beim Kraftprozeß zum Aufschluß von Holz anfallenden Flüssigkeit durch Vergasung
US20110226997A1 (en) * 2010-03-19 2011-09-22 Air Products And Chemicals, Inc. Method And System Of Gasification

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3073672A (en) * 1959-04-15 1963-01-15 Stora Kopparbergs Bergslags Ab Method of gasifying sulphurous cellulose waste liquors
US3323858A (en) * 1964-08-21 1967-06-06 Lummus Co Process for recovering the alkali metal content of spent pulping liquor
SE363651B (fr) * 1969-06-03 1974-01-28 Svenska Cellulosa Ab
SE448173B (sv) * 1985-06-03 1987-01-26 Croon Inventor Ab Forfarande for utvinning av kemikalier fran cellulosaavlut genom pyrolys

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9302249A1 *

Also Published As

Publication number Publication date
JPH07500150A (ja) 1995-01-05
FI940145A7 (fi) 1994-01-12
FI940145A0 (fi) 1994-01-12
SE470066B (sv) 1993-11-01
AU2332792A (en) 1993-02-23
WO1993002249A1 (fr) 1993-02-04
BR9206271A (pt) 1995-10-10
AU655063B2 (en) 1994-12-01
SE9102186L (sv) 1993-01-17
SE9102186D0 (sv) 1991-07-16
NO940149L (no) 1994-01-14
CA2112563A1 (fr) 1993-02-04
NO940149D0 (no) 1994-01-14

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