• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:SE1050206A1
    申请号:SE1050206
    申请日:2010-03-04
    公开日:2010-09-06
    发明作者:Petri Tikka
    申请人:Andritz Inc；
    IPC主号:
    专利说明:

    liquids, such as boiling liquor, white liquor, to a temperature provided by the process.
    Boiling liquor, such as white liquor, is typically heated by passing it to an indirect heat exchange ratio with hot, black liquor withdrawn from a boiler or with steam. For example, the documents US 5,635,026 and EP 477059 show systems in which white liquor. added to a kettle is heated in an indirect heat exchanger with steam or with hot cooking liquor which is drained from the kettle.
    Document US 6,176,971 discloses a system for generating pure steam to be used in the boiler system. Substantially clean usable steam is produced from hot residual liquor (eg black liquor) by passing the residual liquor to a reboiler, and then pressurizing (eg with an ejector, fan or compressor) the clean steam leaving the reboiler. The amount of pure steam produced is increased by subjecting the pure steam side of the steam converter to negative pressure in the steam converter with a steam-driven ejector. The submerged pressure on the side of the clean steam ensures that more heat can be drawn off the black liquor, which in itself gives a larger amount of steam, whereby the input of steam into the ejector also contributes to the production of larger amounts of steam.
    Document US 6,306,252 discloses a further process for generating steam, in which the black liquor from the digester is passed through a heat exchanger, in which e.g. pure process water is heated, after which the pressure of the heated process water is lowered into a relaxation vessel so that pure steam is generated. The steam can be used for spraying wood chips or for indirect preheating of cooking liquors or filtrates used in and around a boiler, for example white liquor. According to an embodiment of US 6,306,252, black liquor is passed from a continuous digester through one or two boilers, in which pure liquid, such as condensate, is boiled to generate steam. The black liquor leaves the boiler and is further cooled in a cooler, where the coolant can consist of white liquor, black liquor or green liquor.
    US 2007013363 discloses a process comprising the following steps: black liquor is generated in a boiler system, the black liquor is fed to an evaporation system without using any pre-evaporation system, the black liquor is relaxed in the evaporation system to generate steam. At least a part of the relaxed steam is used for basing chips in a chip silo and / or for feeding to indirect heat exchangers in the boiler system j. Purpose for preheating. white liquor and / or filtrate for use in the boiler system.
    The known solutions have different systems for preheating white liquor and / or filtrates for use in the boiler system and for improving the energy efficiency of the nose factory. In the known systems, fresh steam from the factory's turbine plant is often used for this purpose. Due to the energy costs, further improvement of the chemical pulp mill's energy efficiency is needed. The heat content of the black liquor extracted from a boiler could also be used more efficiently and the properties of the black liquor could be improved so that the liquor. would be. in a. better forn1 with. consideration of 'further treatment, such as evaporation in the factory's recycling plant.
    Summary of the Invention An object of the present invention is to provide an improved and alternative method of utilizing the heat of black liquor for heating white liquor or a mixture of white liquor and another liquid used for treating fibrous material in the boiler system. A further purpose is to recover heat from black liquor so that the treated black liquor has better properties with regard to the further treatment in the pulp mill's recycling process. One purpose is also to improve the energy mass of the entire pulp mill.
    The present invention relates to a process for heating white liquor or a mixture of white liquor and another liquid for use in a boiler system at a chemical pulp mill, in which process a) black liquor is produced in the boiler system, b) a stream of black liquor is withdrawn from the digester , c) the stripped black liquor is relaxed to generate relaxed black liquor and relaxation steam, d) the relaxing steam is fed to an indirect heat exchange contact in at least one heat exchanger with white liquor and / or a mixture of white liquor and another liquid for heating the white liquor and / or for use in the boiler system, and e) the relaxed black liquor from step c) is led to further heat recovery or evaporation.
    The basic ideas of the present invention are as follows: The white liquor coming to the digester or the digester's liquor circulation (s) is heated indirectly in one / several heaters for white liquor through. to relax black liquor from the boiler system and condense the relaxation steam. in one / several heaters for white liquor.
    The lye flow as. come to. the heater. may also consist of a mixture of white liquor and any other liquid needed in the cooking process.
    According to the invention, the second liquid which forms a mixture with the white liquor may preferably be black liquor or filtrate from. mass washing. According to one embodiment, step d) is performed using a single heat exchanger to heat. It is preferred that it be passed to the white liquor or mixture. heated white liquor or mixture boiler liquor circulation or liquor circulations. According to one embodiment, step d) is performed by using a first heat exchanger and a second heat exchanger to heat the white liquor or mixture. The heated white liquor or mixture from the first heat exchanger is preferably led to the digester's liquor circulation or liquor circulations and the heated white liquor or mixture from the second heat exchanger is led to the top of the digester.
    According to one embodiment, heat is recovered from the stripped black liquor before step c) in a liquid-to-liquid heat exchanger and transferred to a liquid needed in the boiler plant.
    The relaxed black liquor can be fed to the factory's recycling plant, where it is evaporated and incinerated. The relaxed lye can also. fed for further heat recovery, used for pre-treatment of wood chips or used where necessary in the fiber line.
    Impure condensate formed by the flash steam in the heat exchanger (s) is preferably taken to the factory's evaporation plant, where it is treated in a manner known per se. A flow of non-condensable gas (NCG) formed in the heat exchanger (s) is preferably directed to the factory's NCG system.
    Description of the drawings Figure 1 is a schematic view illustrating a system for performing a method according to an embodiment of the invention.
    Figure 2 is a schematic view illustrating a SOITI other embodiment of the invention.
    Detailed Description of Preferred Embodiments In FIG. 1 shows a system for generating steam in a cooking plant and for treating black liquor so that the factory's heating efficiency is improved. The fiber line system typically comprises a chip silo (not shown), in which basing of wood chips or other cellulosic material with steam takes place, liquid is added to form a slurry, to which the slurry is pressurized, fed or several treatment vessels (may be an impregnation vessel, prehydrolysis process vessel or any other vessel). An optional impregnation vessel 2 is shown in FIG. l followed by a boiler 3 (this section is also referred to as a cooking system).
    The cooking system can also be a system with a single vessel so that the separate impregnation vessel 2 is omitted. The slurry of chips and cooking liquid is fed through a line 4 to the top of the impregnation vessel 2 and further from the bottom of the impregnation vessel to the top of the digester 3. a wire 5. Only the components that. does anyone have. relevance to the invention is shown in the drawing, whereby other types of chip basing or feeding or boiler circulations can of course be arranged in the boiler system. At least a black liquor flow 120 - 160 ° C and at a dry matter content of 12 - 17%), (typically at a temperature of is drawn by the boiler system through a line 6 and fed further through a line 7 in a provided relaxation vessel 8. The line 6 may be with a liquid-to-liquid heat exchanger for recovering heat from the black liquor to be transferred to a liquid needed in the boiler plant.
    According to the invention, hot black liquor drawn by the digester is led 120 - 160 ° C to the relaxation vessel 8, typically at a temperature of and at a dry matter content of 12 - 17% where the pressure of the lye is lowered to produce relaxation steam, typically at a temperature of 100 - 130 ° C, and relaxed black liquor, One or whose dry matter content can be increased by 2 - 4% during relaxation. several flows / s of black liquor drawn from the digester through one or more outlets can be led to the relaxation vessel. The flow of the black liquor led to the relaxation vessel is such as is needed to generate the relaxation vapor required for heating white liquor. The black liquor can thus be relaxed to the maximum level.
    The relaxation steam from the black liquor relaxation vessel 8 is supplied to a white liquor heat exchanger 9 through a line 10. White liquor is fed through a line 11 in the heat exchanger 9 to an indirect heat exchange contact with the relaxation steam. The preheated white liquor. fed through. a line 14 to the liquor circulations 15 of the boiler 3.
    The relaxation vapor contains volatile compounds, such as one (NCG) as sulfur compounds. These compounds are passed to the crude condensate and to a flow of uncondensable gases. The crude condensate is led from to the heat exchanger 9. the heat exchanger 9 is passed through a line 12 to the factory evaporation plant, where it is treated in a manner known per se. The NCG flow is led through a line 13 to the factory NCG system (not shown).
    That in FIG. 1 also shows a second heat exchanger 16, into which white liquor is fed through a line 17 from the line 11. A part of the relaxation steam from the relaxation vessel 8 is supplied to it. the second heat exchanger 16, where the steam comes to an indirect heat exchange contact with the white liquor from the line 17. The heated white liquor is fed from the second heat exchanger 16 through a line 18 to the top 24 of the boiler 3 to be used as a boiling liquor.
    The relaxed black liquor is passed through a line 19 to the factory's evaporation plant, where the black liquor is concentrated to a high dry matter content before the combustion. A recycling boiler owns the black liquor can also be taken to further pre-treatment rooms. The relaxed recycling, used to wood chips or used where needed in the fiber line.
    Other liquids can be added to the white liquor to be heated in the heat exchanger (s). in FIG. 1 filtrate flows from the plant mass wash in a line 25. The filtrate can be added through a line 20 in the white liquor flowing in line 11 to the heat exchanger 9. The filtrate can also be added through a line 21 in the white liquor flowing in line 17 to the heat exchanger 16. Also black liquor which has been withdrawn from the boiler is fed through lines 22 and 23 to the white liquor streams to be heated. FIG. 1 thus also shows such embodiments of the invention, in which a mixture of white liquor with stripped black liquor and / or filtrate is formed and heated according to the invention in the heat exchangers by means of the black steam vapor release steam.
    The second white liquor heat exchanger 16 is typically needed only for one in FIG. 1 shown boiler system with two vessels.
    The impregnation vessel 2 is optional, and when omitted, the second heat exchanger may become unnecessary.
    FIG. 2 shows an alternative detail of FIG. 1, in which embodiment the black steam release steam is used in a heat exchanger 9 for white liquor, in which case the digester is a digester with a single vessel without an impregnation vessel upstream of the digester.
    Hot black liquor drawn from the digester is led through a line 7 to the relaxation vessel 8, where the pressure of the liquor is reduced to produce relaxation steam. The relaxation steam from the black liquor relaxation vessel 8 is passed through a line 10 to a white liquor heat exchanger 9. The heat in the relaxation steam in a line 10 is recovered in the heat exchanger 9, where the steam is carried to an indirect heat exchange ratio with white liquor from a line 11. The liquid to be heated may also consist of a mixture of white liquor and some other liquid which. needed in the cooker. The heated white liquor or mixture is passed through a line 14 to the digester's liquor circulation or liquor circulations.
    Impure condensate formed in the heat exchanger is brought to the factory and treated in a manner known per se. An NCG flow through a line evaporator, where what is formed in the heat exchanger is led through a line 13 to the factory's NCG system.
    The present invention has at least the following advantages: because to - The overall heat economy of the plant is improved, the dry matter content of the black liquor led to the evaporation plant increases. Increased dry matter content is a consequence of the relaxation of the black liquor. Steam consumption and capacity requirements are reduced in the factory's evaporation plant.
    - The investment costs of the evaporation plant are reduced due to the lower capacity requirement.
    - Methanol recovery in the factory's total system is improved, evaporated from because. the first fractions of black liquor water are condensed in a specialized heat exchanger. In this process, the relaxation steam, the methanol content of which is high, is condensed in a specialized separate (ie heating surface heat exchanger (s) for white liquor) to produce crude condensate which is recycled. Treating the crude condensate having a high methanol content is more advantageous than treating a weakly impure condensate which would be formed if the black liquor flash vapor were mixed with vapors having a low methanol content.
    权利要求:
    Claims (7)
    [1]
    1. A process for heating white liquor or a mixture of white liquor and another liquid for use in a boiler system at a chemical pulp mill, in which process a) black liquor is produced in the boiler system, b) a stream of black liquor is drawn from the digester, c ) the stripped black liquor is relaxed to generate relaxed black liquor and relaxation steam, d) the relaxing steam is fed to an indirect heat exchange contact in at least one heat exchanger with white liquor and / or a mixture of white liquor and another liquid for heating the white liquor and / or mixture to used in the boiler system, and e) the relaxed black liquor from step c) is led to further heat recovery or evaporation.
    [2]
    Process according to Claim 1, characterized in that the second liquid which forms a mixture with the white liquor in step d) consists of black liquor or filtrate from mass washing.
    [3]
    Process according to Claim 1 or 2, characterized in that step d) is carried out by using a single heat exchanger to heat the white liquor or the mixture. characterized by being led to
    [4]
    A method according to claim 3, heated white liquor or the mixture boiler liquor circulation or liquor circulations.
    [5]
    Process according to Claim 1 or 2, characterized in that step d) is carried out by using a first heat exchanger and a second heat exchanger for heating the white liquor or mixture. 10 11
    [6]
    Method according to claim 5, characterized in that the lye circulations are led from the first to the white liquor and the heated liquor or mixture heated mixture is led to the liquor circulation of the boiler heat exchanger or from the second heat exchanger to the top of the boiler.
    [7]
    Method according to one of the preceding claims, characterized in that heat is recovered from the stripped black liquor before step c) in a liquid-to-liquid heat exchanger and transferred to a liquid needed in the boiler plant.
    类似技术:
    公开号 | 公开日 | 专利标题
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    SE1050126A1|2010-08-10|Process and system for generating steam in a boiling plant at a chemical pulp mill
    CA2565358C|2014-01-14|Fiberline system and method using black liquor flashed steam
    EP3114274B1|2018-05-02|Method and arrangement for generating steam at a digesterplant of a chemical pulp mill
    CN109847394A|2019-06-07|A kind of system and method that ethylene glycol rectifier unit process waste recycles
    JP5130302B2|2013-01-30|Method for producing cellulose pulp with excellent energy efficiency in a continuous digester
    SE528574C2|2006-12-19|Steam generating system for digester plant for chemical cellulose pulp production, has pressure reduction arrangement to reduce pressure of re-heated liquor, while expelling liquor steam to steam converter for heating process fluid
    SE527058C2|2005-12-13|Continuous cooking process with improved heat economy
    SE528448C2|2006-11-14|Process for impregnating wood chips in a continuous cookery system
    WO2016038247A1|2016-03-17|Method of generating steam at a digester plant of a chemical pulp mill
    SE534130C2|2011-05-03|Method and apparatus for heating a chip slurry in the transfer line between impregnation vessels and boilers in the production of pulp
    US10982388B2|2021-04-20|Method and arrangement for generating process steam
    EP3464715B1|2021-07-28|Method of producing chemical pulp at a digester plant of a chemical pulp mill
    FI126251B|2016-08-31|Method and device for heating wood chips slurry
    同族专利:
    公开号 | 公开日
    CL2010000161A1|2011-02-18|
    BRPI1000659A2|2011-03-22|
    FI20090079A|2010-09-06|
    CA2692089A1|2010-09-05|
    SE534699C2|2011-11-22|
    US20100224335A1|2010-09-09|
    RU2532568C2|2014-11-10|
    FI20090079A0|2009-03-05|
    RU2010108200A|2011-09-20|
    US8808498B2|2014-08-19|
    CN101824767A|2010-09-08|
    JP2010203030A|2010-09-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPS6059189A|1983-08-24|1985-04-05|Beloit Corp|Multi-stage digestion of wood pulp|
    AT125010T|1990-09-20|1995-07-15|Kvaerner Pulping Tech|Soaking with black liquor before the white liquor is fed.|
    US6123807A|1997-02-18|2000-09-26|Kvaerner Pulping Ab|Method for the continuous cooking of pulp|
    US6306252B1|1995-04-10|2001-10-23|Andritz-Ahlstrom Inc.|Heat recovery from spent digester cooking liquor|
    US5635026A|1995-11-13|1997-06-03|Ahlstrom Machinery Inc.|Cooking cellulose material with high alkali concentrations and/or high pH|
    US6103058A|1997-08-07|2000-08-15|Kvaerner Pulping Ab|Method for the continuous cooking of pulp|
    US6176971B1|1998-11-18|2001-01-23|Andritz-Ahlstrom Inc.|Heat economy enhancements for the recovery and use of energy obtained from spent cooking liquors|
    FI117479B|2002-07-22|2006-10-31|Metsae Botnia Ab Oy|Method for producing thermal and electric energy|
    US7556713B2|2004-06-22|2009-07-07|Andritz, Inc.|Method and system for feeding cellulose chips to a high pressure continuous cooking system|
    FI120547B|2004-10-04|2009-11-30|Metso Paper Inc|Alkaline cooking process and pulp making plant|
    US20070131363A1|2005-10-24|2007-06-14|Andritz Inc.|Fiberline systems, processes and methods|WO2012147094A1|2011-03-25|2012-11-01|Keswani, S.L.|Method and system for extraction of black liquor from a horizontal tube continuous digester|
    CN102226319B|2011-06-03|2013-04-10|长沙理工大学|Batch cooking cold blow device and cold blow method|
    US9103070B2|2012-02-13|2015-08-11|Andritz Inc.|Flash tank with adjustable inlet|
    CN103184702B|2013-04-26|2015-03-11|朱运江|Papermaking pulping reactor|
    US9127403B2|2013-05-28|2015-09-08|Andritz Inc.|Flash tank with flared inlet insert and method for introducing flow into a flash tank|
    US9458703B2|2013-12-26|2016-10-04|Superior Graphite Co.|Compressible carbonaceous particulate material and method of making same|
    FI127386B|2014-03-05|2018-04-30|Andritz Oy|A process for steam generation at a pulp mill digester|
    FI20145784A|2014-09-08|2016-03-09|Andritz Oy|Water vapor development at the pulp mill digester|
    CN104404804B|2014-10-21|2016-10-05|华南理工大学|A kind of chemical pulp or dissolving pulp preparation method and test-type displacement cooking device thereof|
    FI20165470A|2016-06-06|2017-12-07|Andritz Oy|A process for producing chemical pulp at a pulp mill digester|
    FI127474B|2017-01-20|2018-06-29|Valmet Technologies Oy|Method and system of thermal recovery relating to the operation of a dissolver of a chemical recovery boiler|
    法律状态:
    2016-11-01| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    FI20090079A|FI20090079A|2009-03-05|2009-03-05|Heat recovery from waste cooking liquor at a pulp mill digester|
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