• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:

    公开号:SE534130C2
    申请号:SE0801458
    申请日:2008-06-23
    公开日:2011-05-03
    发明作者:Anthony Calandra
    申请人:Andritz Inc；
    IPC主号:
    专利说明:

    534 130 chemical boiling. The top separator 103 in the upper inner area of the kettle 104 feeds the chips to the inner chamber of the kettle.
    When the chips and lye flow through the top separator 103, from the kettle lye. The liquefied flux from the stripped liquor flows through a drainage device 110 in line, a portion of the black liquor is drained through a top separator circulation line 108 which directs the drawn liquor to a heat recovery unit 114 through a line 112 or to a liquor circulation line 116.
    A conventional liquor circulation line 116 transfers a portion, for example 90%, of that through the drainage device 110 to the bottom of the chip impregnating vessel 102 or to the line 106 in line the lye chip outlet in the chip slurry. A liquor pump 118 can be used to pass the liquor through line 116 and to the chip slurry flowing from the impregnation vessel and to the boiler vessel. The withdrawn liquor in pretreatment is discharged from the impregnation vessel and transferred through line 106 to the boiler vessel. line 116 is added to the chip to which the stripped liquor is added to the chip slurry in line 106 at or near the bottom of the impregnation vessel to increase the slurry content of the slurry for transport through the line. The liquor from line 116 is added to the chip slurry to reduce the chip concentration in the slurry and facilitate the transfer of chips through the chip slurry line 106. The slurry flows from the impregnation vessel through the conduit 106 to the upper part of the boiler vessel 104.
    Conventionally, a small part flows, e.g. 10%, of the withdrawn liquor through line 112 to the heat recovery system ll4, e.g. to the heat exchanger.
    The temperature of the stripped liquor flowing through the drainage device 110 in line and the heat exchanger is, for example, 110 ° C (Celsius). Heat energy from the drawn liquor can be used in a heat exchanger to generate, for example, low-pressure singing, e.g. steam at a pressure of 1 bar, for use at the pulp mill.
    The content of lye in the chip slurry L / W (lye weight in relation to chip weight) in the impregnation vessel can be 2.5. In the chipping slurry line 106, the content of lye in the chipping slurry (L / W) 106) is increased in or by adding lye (the chipping line in the bottom of the impregnation vessel in the area of the beginning of the chipping slurry line 106. chips through the chip slurry line 106. When the slurry reaches the boiler vessel 104, the liquor / chip ratio (L / W) is reduced, for example, by drawing off liquor at the top separator.
    Heat is often transferred to the chips in the pan. As a rule, a kettle operates at a higher temperature than an impregnation vessel. An impregnation vessel can, for example, at a temperature of 110 ° C and the boiler vessel can function at a temperature of 140 ° C. The chip slurry reaches the top separator at a lower temperature than the temperature in the kettle. Heat, e.g. medium pressure steam through a line 136, is transferred to the vessel to raise the temperature of the chips in the boiler vessel.
    Average pressure steam 146 is typically at a pressure of 10 - 12 bar and at a temperature of 180 ° C - 190 ° C. The temperature of the cooking vessel tends to be at its lowest at the upper inlet of the vessel and it rises progressively in the direction of the vessel. downwards through i.a. refers to The kettle vessel 104 generally comprises several planes of sieves, sieves on the upper plane of the kettle vessel (where sieves 120, 122). "upper" 121 which lies above the lower plane of the strainer The strainer (s) 122 (usually called wash strains) on 534 '130 the lower plane of the boiler may be close to the bottom of the boiler, (1/3) - quarter Lut is drained through it upper sieve 120 and is fed, for example, into the lower third of the pan (1/4). through a line 124 for lye to the heat recovery system 114. Lye to be recirculated through the digester is removed with the upper plane screen 121 and fed to a leach recirculation line 126.
    Other sources of liquor for the circulation in the boiler may include washing liquor (W.L.) The washing liquor 140, 140 and a system 142 with cold blowing liquor. the cold blow valves 142 and the liquors drawn from the screen 121 are joined in the line 126 and pumped 121 to a heater 144. The liquor for recirculation is heated in the heater 144 which uses a steam source 146 for heat energy. Typically, the circulation closed through the line 126 is re-fed to the vessel at a different, e.g. higher, plane than the plane, from which the lye was subtracted.
    The liquor drawn from the lower plane (s) of strainers 122 can be circulated through a conduit 128 to the digester on an upper plane or discharged to the heat recovery system. The liquor from the lower plane (s) of strainers 122 tends to be hotter, for example 140 ° C, than the liquor withdrawn from the top separator 103 (through line 108) 120, the hot liquor (in and the liquor withdrawn from the strainers 121 on the upper levels 126). It (through lines 124, line 128) from the lower area of the digester is recirculated to the upper part of the digester through a line 132 and to the liquor. the sieves on the lower plane and near the pulp outlet are supplied with cold blowing, for example cooled water liquor, so that the temperature of the pulp discharged to a pump 130 without heat transfer is lowered from the digester through a line 145. The cold blowing is taken from a source 142 of cooling liquor and it passes cold blow cooler 143 through one and wires to direct the cold blow to the bottom of the digester. 534 130 As a rule, a large part flows, e.g. 70%, of the liquor to 114 drawn off through line 122. Leach to line 128 from the lower plane screens 122 can be divided, for example, in such a way that a first part, for example 70% 80, flows to the heat recovery system 114; a second part, for example 10% - 18%, is recycled 128 from the lower plane filters the heat recovery system deducted%, of the liquor through the line 128 of the liquor is pumped 130 to the line 126 to the boiler vessel, and a part, to 12%, of the liquor is pumped 130 through line 132 to the upper part of the digester. third example 8% - Excess black liquor, from the strainers in the kettle and not re-fed to the vessel or e.g. liquor residues, which have been stripped of the chip 106 for chip slurry, flow through the heat recovery system 114. A part of all flows of excess liquor, e.g. from the in-line drainage device and the upper and lower exhaust screens, tend to flow through the heat recovery system, where heat energy from the excess sludge is converted to steam, typically to low pressure steam, for use at other plants in the plant.
    The pressure of the low pressure steam is typically 1 bar or lower at a temperature of about 100 ° C, for example 90 ° C - 110 ° C.
    To raise the chip's boiler vessel, medium pressure steam 146 is often supplied to the boiler vessel through line 136 temperature in and the heater 144. Medium pressure steam flows in at a temperature of 180 ° C - 190 ° C and raises the chip temperature in the boiler vessel in order to promote boiling chemical reactions, e.g. decompose lignin that binds the cellulose fibers in the chips.
    Medium pressure steam requires energy to be produced. Furthermore, evaporators are usually needed to divert condensate originating from the steam injected into the boiler vessel. 534 130 There has long been a need to reduce the energy requirements of a pulp preparation system including systems with an impregnation vessel and a boiler vessel. In particular, there has long been a need for techniques for transferring heat to the chips in the kettle, which improves the pulp preparation system and reduces the need for steam from external sources, such as the steam source 146. Energy Efficiency BRIEF DESCRIPTION OF THE INVENTION In a first aspect of the present invention there is provided a method for heating a chip slurry in a pulp preparation system comprising an impregnation vessel and a chemical boiling vessel, a chip which method comprises the following steps: being impregnated with a lye in the impregnation vessel; the chips are transferred from the impregnation vessel to the upper plane of the cooking vessel; lye is removed from the lower plane of the kettle, the drawn lye having a temperature which is substantially higher than the temperature of the chips in the impregnation vessel; a part of the lye subtracted from the lower plane of the kettle is added to the chips which are to be or are being transferred from the impregnation vessel to the kettle, and the chips transferred are heated with the heat energy in the drawn lye.
    In a second aspect of the present invention there is provided an apparatus for heating a pulp preparation system comprising an impregnation vessel and up a chip slurry in a chemical boiling vessel, said apparatus comprising: one from the chips in the transfer line to the chip transfer line flows from the impregnation vessel to the cooking vessel; liquor is drawn from chips extending from the impregnation vessel to the boiler, a strainer on the lower plane of the boiler, wherein from the strainer on the lower plane, and a first conduit for liquor extending from the strainer on the lower plane to the transfer line for chips, the liquor being 534 130 from the chip transmission line. subtracted the strainer on the lower plane is added It is described that black liquor subtracted on the lower or lower strainers in a boiler is added to the chip slurry which is transferred from an impregnation vessel to a boiler vessel. The hot liquor transfers heat to the chip slurry before the slurry reaches the top separator. The chips entering the kettle are at a higher temperature than they would be if black liquor had not been added. The heated chip slurry in the top separator reduces the need for heat energy that needs to be transferred to the kettle.
    The kettle's energy requirements for black liquor are reduced, as hot chips are added to the chip slurry before the chips reach the boiler.
    It is also described that a method has been developed for heating a chip slurry in a pulp preparation system comprising an impregnation vessel and a chemical chip vessel the chip is transferred to boiling, which method comprises the following steps: being impregnated with a lye in the impregnation vessel; from the impregnation vessel to the upper plane of the kettle; lye is withdrawn from the lower plane of the kettle, the peeled lye having a temperature substantially higher than the temperature of the chips in the impregnation vessel; and lye which has been deducted from the lower plane of the kettle is added to the chips which are to be shipped from the kettle. transferred to the impregnation vessel It is also described that a method has been developed for heating a chip slurry in a pulp preparation system comprising an impregnation vessel and a chemical chip vessel the chip is transferred to boiling, which method comprises the following steps: being impregnated with a liquor in the impregnation vessel; from the impregnation vessel to the top separator of the kettle; lye is removed from the sieve of the boiler vessel on the lower plane, the extracted lye having a temperature which is at least 20 ° C higher than the temperature of the chips in the impregnation vessel; and the liquor drawn from the sieve of the boiler vessel on the lower plane is added to the chips which are to be or which are being transferred from the impregnation vessel to the boiler vessel.
    It is also described that a device has been developed for heating a chip slurry in a pulp preparation system comprising an impregnation vessel and a chemical cooking vessel, the device comprising: a chip transfer line extending from the impregnation vessel to the digester, the chip in the chip transfer line flows from the impregnation vessel to the boiler vessel; a strainer on the lower plane of the kettle, hot liquor being drawn from the strainer on the lower plane, and a first line of liquor extending from the strainer on the lower plane to the chip transfer line, the liquor subtracted from the strainer on the lower plane being fed to the transfer line for wood chips.
    The following observations are relevant to all aspects of the present invention. developed to recover heat from the excess black liquor deducted from the boiler sieve group An apparatus and method have, for example, the lower sieve group or bottom (usually referred to as washing sieves) for the purpose of heating the black liquor in the chip line for the chip slurry between the top of the boiler and the bottom of the impregnation vessel .
    A chemical pulp preparation system for cooking wood chips comprises an impregnation vessel and a vessel for chemical boiling. The impregnation vessel can receive a fed supply of chips at an upper inlet. The impregnation vessel is located in the pulp flow pulp preparation system. The impregnation vessel pre-treats chips upstream of the boiler vessel in the direction through 534 130 with cooking liquor in the vessel. The impregnation vessel is a pre-treatment vessel for the vessel for chemical boiling.
    Chips and lye of the impregnation vessel from through a discharge flow a transfer flow or (chip slurry) as lower outlet can circulation line for chips (ie a transfer line) the boiler vessel for example to a top separator in the upper area. When the chip slurry flows through such a top separator, some of the lye can be drained through strainers in the top separator and flow out of the digester.
    The content of lye in the wood chip slurry (L / W) The content of lye in the impregnation vessel may be lower than the boiler vessel. chip slurry in The content of lye in the chip slurry in the transfer flow can increase the L / W concentration level at the inflow into the kettle. In the digester, liquor from the fed chip stream can be drained from a top separator and flow to an in-line drainage device. The removal of lye from the top separator can reduce the L / W ratio of the chips in the digester to an L / W level that is lower than the level in the transfer line. Some, for example about half, ie. below about 70%, preferably below about half, more preferably below about 30%, of the liquor flow passing through the drainage device in line can be returned to the chip flow flowing from the impregnation vessel to the digester. The recycled lye can be added to the bottom of the impregnation vessel or the beginning of the chip circulation line. One. pump can force the liquor through the liquefied circulation line and into the chip slurry in the transfer line. The recycled lye can be added to increase the proportion of lye, for example to increase the L / W ratio, in the flowing impregnation vessel and the boiler vessel. chip slurry which, through the transfer line between A second portion of the liquor flow through the drainage device in line can flow to a heat recovery system, e.g. a 534 130 heat exchanger. The volume of the second portion of the liquor deducted from the top separator can be about half (M), i.e. more than about 30%, preferably more than about half, more preferably more than about 70%, of the volume of the liquor flowing through the drainage device in line.
    A relatively large part of the black liquor passing through the drainage device in line (for example, half, or more than about 30%, preferably more than about half, more preferably more than about 70%, of the liquor passing through the drainage device in line) can be directed to the heat recovery system, in comparison with the portion of liquor from the in-line drainage device flowing to the heat exchanger in a conventional system. A relatively small portion of the black liquor flowing through the drainage device in (half, preferably below about half, more preferably below about 30%, line example or below about 70%, of the liquor passing through the drainage device) can be mixed with hot black liquor and fed to the transfer line. for chip slurry. The portion that passes through the drainage device in line and is controlled to the chip the amount of lye needed in the transfer line for chips and passed to the transfer line for may vary depending on the heat recovery.
    The chips and cooking liquor that are discharged from the cooking vessel, for example from the top separator, flow downwards through the cooking vessel. Strainers on different levels of the kettle can draw black liquor from the chip slurry in the vessel. Such strainers are conventional and well known in chemical pulp cooking. Subtracting and circulating lye from upper strainers is conventional. from the suction strainers on the upper level of the kettle can flow to a Black liquor that is stripped of heat recovery system. Lye from recirculation screens on the upper planes can also be circulated to the upper area of the vessel, for example to the top separator, via a circulation line 534 130 ll for lye. In addition, white liquor (W.L.) can be supplied to a liquor circulation line to ensure a sufficient amount of liquor in the upper part of the cooking vessel.
    Lower strainer (s), such as wash strainer, in the kettle can produce a significant flow of stripped hot black liquor. The lower strainers may be located in the lower third (1/3) or quarter (1/4) of the height of the pan. The amount of black liquor from the transfer line (s) for slurry may be, for example, three (3) - four (4) sieves to the upper parts of the digester. which is deducted from the lower strainer (s) times the amount of black liquor flowing from the lower part of the black liquor from the lower strainer, for example 25%, can flow to the upper areas of the kettle.
    The hot black liquor, for example from the lower strainer (s), can be drained through a liquor washing line. Some, for example about 30% - 80%, preferably about 50% - 80%, more preferably about 70% - 80%, and most preferably about 70% - 75%, leaching to a line which transfers the hot liquor to the chip slurry flows from to the kettle through a chip circulation line. A pump may flow from the drawn hot liquor from the line as the impregnation vessel raises the pressure of the hot black liquor up to the pressure prevailing in the line which transfers liquid which has passed the drainage device and is directed to the chip circulation line or up to the pressure prevailing in the transfer line.
    The hot black liquor, e.g. from the lower sieves, can be mixed with the colder liquor from the top separator in the line which transfers liquid which has passed the drainage device and is directed to the circulation line for chips. The mixed streams of black liquor can be fed to the chip transfer line (channel) near the impregnation vessel and / or the beginning of the chip transfer line. 534 130 12 e.g. can about 30% - 80 Of the black liquor deducted from the lower level of the boiler, from the washing strainers (line for leach washing),%, more preferably 50% - 70%,%; or about 30% - 80%, preferably about 70% - 80%, and most preferably 70% - 75 80%, and most preferably about 70% - 75%; preferably about 50% - more is circulated to a circulation line between the upper part of the digester and the bottom of the impregnation vessel downstream of the drainage device in line.
    The one from the bottom of the cooker, e.g. from the lower strainer (s), the black liquor subtracted temperature is generally higher than the black liquor subtracted from the top separator. The temperature of the black liquor subtracted from the (s> typically, for example, the lower screen (s) is about 140 ° C and the temperature of the black liquor subtracted from the top separator is usually about 140 ° C.
    Below such a pulp outlet, cold blowing, sieves on the lower level and near, for example, cooled washing liquor, can be added to lower the temperature of the pulp which is discharged from the digester. The cold blowing can be taken from a source of cooling liquor and it can pass through a cold blowing cooler and pipes that control the cold blowing to the bottom of the boiler.
    The hot black liquor can be fed to the line which transfers liquid which has passed the drainage device and is directed to the chip circulation line to enable mixing of the black liquor with the liquor from the top separator before the mixed liquor streams are fed to the chip transfer line. The temperature of the mixed liquor in the pipe that transfers liquid that has passed the drainage device and is controlled to chips can be higher, 20 ° C temperature in the impregnation vessel. The hot liquor from the line that transfers liquid that has passed the drainage device and is directed to the chip circulation line, optionally through a heater chips in the PUWPI UP transfer line. The elevated temperature of the chips in the transmission line reduces the need for energy to heat the chips in the boiler. from the temperature (s) The hot black liquor, for example the lower strainer (s), is used to raise the chips to the boiling temperature or to the boiling temperature.
    Due to the reduced need for heat energy, the amount of medium pressure steam fed through a steam line in the upper part of the boiler can be reduced. Medium pressure steam is typically steam at a pressure of 10 - 12 bar and at a temperature of 180 ° C - 190 ° C.
    The hot black liquor withdrawn from the lower plane of the digester, optionally via a pump, can be added under pressure in the liquor in the line which transfers liquid which has passed the drainage device and is directed to the chip circulation line so that there is no relaxation, for example evaporation, in any significant degree. The mixture of black liquor in the line which transfers liquid which has passed the drainage device and is directed to the circulation line for chips can be pumped under pressure to the transfer line for chips and preferably without relaxing the liquor.
    The lye fed to the chip transfer line increases the lye / wood ratio (L / W) in the L / W ratio in the impregnation vessel and the digester is typically lower than the L / W line. the ratio in the transfer line for chips due to the liquor supplied to the line and drawn off in the top separator.
    By using the liquor, for example the washing liquor, to heat the chip slurry in the line which transfers liquid as to the circulation line for chips, the amount of medium pressure steam which has passed the drainage device and is controlled to the upper part of the digester can be significantly reduced, for example 534 130 14 approx. Reducing the amount of medium pressure steam needed to heat the chips in the upper part of the kettle results in a corresponding reduction in the energy requirements of the pulp preparation process. The reduction of the amount of medium pressure steam injected into the boiler vessel also reduces the water condensate that forms in the boiler and thus the need to use evaporators becomes less.
    BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a conventional chemical boiler system for chips comprising an impregnation vessel and a vessel for chemical boiling.
    FIG. 2 schematically shows a chemical boiler system for chips comprising an impregnation vessel and a chemical vessel where hot is added in boiling, from the boiler vessel flows from black liquor deducted from the lower area of the chip slurry as the impregnation vessel to the boiler vessel.
    DETAILED DESCRIPTION OF THE INVENTION A system and method have been developed for recovering heat from the excess black liquor withdrawn from the lower sieve groups or the lower boiler sieve group (usually referred to as wash strains) for the purpose of heating the black liquor in the chip slurry line. and the bottom of the impregnation vessel.
    FIG. 2 is a schematic chemical pulp preparation system 10 for cooking chips comprising a diagram of an impregnation vessel 12 and a vessel 14 for chemical cooking.
    The impregnation vessel receives an inlet supply 23 of chips at an upper inlet 15. The impregnation vessel 12 is located upstream of the boiler vessel 14 in the direction of the chip flow through the pulp preparation system. The impregnation vessel pre-treats chips with cooking liquor in the vessel.
    The impregnation vessel is a pre-treatment vessel for the vessel for chemical boiling.
    Chips and liquor (chip slurry) discharged from the chip flow line 18 to a top separator 20 in the lower outlet 16 of the impregnation vessel can pass through the upper area of a kettle. As the chip slurry flows through the top separator, a portion of the liquor is drained through strainers into the top separator and it flows out of the digester through a liquefied circulation line 21.
    The content of lye in the chip slurry (L / W) in the impregnation vessel 12 may be the boiler vessel. lower than the content of lye in the chip slurry in The content of lye in the chip slurry in the transfer flow (in line 18) increases L / W concentration levels in the impregnation vessel and the boiler vessel in order to transfer the chips from the impregnation vessel through line 18 to the boiler vessel 14. In the digester, liquor is withdrawn from input the chip flow (in line 18) from the top separator 20 to a circulating line 21 for liquor flows The stripping of liquor from and it to a drainage device 22 in line. the top separator reduces the L / W ratio of the chips in the digester to an L / W level which is lower than the level in the line 18. A part, for example about half of the flow, of the liquor passing from the line 21 through the drainage device in line 22 through a circulating line 24 for liquor and returned to the chip stream flowing from the impregnation vessel to the digester.
    The recycled lye is supplied to the circulation line 24 for the bottom 16 of the impregnation vessel or the beginning of the chip circulation line 18. A pump 17 can force the liquor through the line 24 and into the chip slurry in the line 18.
    The recycled liquor is added to increase the proportion of the liquor, for example to increase the L / W ratio, in the chip slurry flowing through the conduit 18 between the impregnation vessel and the boiler vessel. 534 130 16 A second part of the liquor flow through the drainage device 22 flows in line through a liquor line 26 to a heat recovery system 28, e.g. a heat exchanger. The volume of the second part of the excess sludge subtracted from the top separator may be about half (2) of the volume of the excess sludge as. flows through. the drainage device 22 in line.
    A relatively large portion of the black liquor SOIII PASSENGER the flue drainage device 22 in line (e.g., half of the liquor passing through the drainage device) is directed to the heat exchanger 28, compared to the portion of lye from the drainage device in line flowing to the heat exchanger in a conventional system shown. in FIG. 1. A relatively small portion of the black liquor flowing through the drainage device in line (e.g., half of the liquor passing through the drainage device) is mixed with the chip 18 for chip slurry. flows through line 24, where it is supplied with hot black liquor (from line 42) and The portion passing through to the chip transfer line 18 may vary depending on the drainage device in line and the amount of liquor needed in the chip transfer line 18 is controlled and passed to heat recovery.
    The chips and cooking liquor discharged to the cooking vessel from the top separator 20 flow down through the cooking vessel 14. Strainers 30, 31, 32 on the different planes of the cooking vessel draw black liquor from the chip slurry in the vessel. The strainers are conventional and well known in chemical pulp cooking. Subtracting and circulating liquor from them and 31, the upper strainers 30 are conventional and correspond, for example, to the withdrawal and circulation of the strainers 120, 121 in FIG. The black liquor which is drawn off from the extraction screens 30 on the upper surface of the kettle consists of black liquor which can flow to the heat recovery system 28 via a leach line 34. Liquid from the recirculation screens 31 on them is circulated to the upper area 38 of the vessel. , via a circulating line 36 for liquor.
    (W.L.) 52 the liquor circulation line (s) 50 to ensure a sufficient amount of liquor in the upper part of the kettle.
    In addition, white liquor can be supplied. The lower one (s) of the cooking vessel 14 provides a considerable flow of the drawn hot screen (s) 32, for example washing screens, in black liquor. The lower strainers may be located at (1/3) (1/4) height. The amount of black liquor drained from the lower third or quarter of the bottom strainer (s) of the boiler slurry line 18 may be, for example, three (3) - four (4) times the amount of black liquor flowing from the lower strainer to the boiler upper parts. A portion of the black liquor from the lower screen, for example 25%, may flow to the upper areas of the kettle through the conduits 48 and 50.
    The hot black liquor that is drained from the lower strainer (s) 32 Some of the drained liquor is drained off. a line 40 for lye washing. 80%, line 40 to line 42 which transfers the hot liquor to the boiler vessel 14 via the chip circulation line 18. A pump example 70% - the chip slurry flowing from the impregnation vessel 12 41 can raise the pressure of the hot black liquor up to the pressure prevailing in the lines 24 or in the line 18. The hot black liquor from the lower screen (s) 32 can be mixed with the colder liquor from the top separator in line 24. The mixed streams of black liquor are fed to the chip transfer line (channel) 18 near the impregnation vessel and / or the beginning of the chip transfer line.
    Of the extracted black liquor from the washing strainers 32, about 30% - 80%, (in line 40) more preferably 50% - 70%, and most preferably 70% - 75%, can be circulated to the circulation line between the upper part of the digester and the bottom of the impregnation vessel. downstream of the drainage device in line.
    The temperature of the black liquor subtracted from the lower strainer (s) 32 is generally higher than that of the black liquor subtracted from the top separator to lines 21 and 24.
    The temperature subtracted from the lower screen (s) of the black liquor (s) 32 is typically, for example, about 140 ° C and the temperature of the black liquor subtracted from the top separator is usually about 10 ° C.
    Below the sieves on the lower plane and near the pulp outlet, cold blowing, for example cooled washing liquor, is supplied to lower the temperature of the pulp discharged from the digester through a conduit 145. The cold blowing is taken from a source 142 by refrigerated cold blowing cooler 143 wires which control the cold blowing to the digester bottom . and it passes through one and The hot black liquor can be fed to the liquor line 24 to enable mixing of the black liquor with the liquor from the top separator before the mixed liquor streams are fed to the chip transfer line 18. The temperature of the mixed liquor in the line 24 is substantially higher, for example at least 20 ° C higher, than the temperature of the chip slurry in the impregnation vessel 12.
    The hot liquor from line 24 and the pump 17 heat the chips in line 18. The increased temperature of the chips in line 18 reduces the need for energy to heat the chips in the pan. the lower strainer (s) of The hot black liquor from the 32 (n) 32 is used to raise the temperature of the chips to the boiling temperature or to the boiling temperature. Due to the reduced need for heat energy, the amount of medium pressure steam 44 fed through a steam line 46 to the upper part of the kettle 534 130 19 can be reduced. Medium pressure steam is typically steam at a pressure of 10 - 12 bar and at a temperature of 180 ° C - 190 ° C.
    The hot black liquor from line 42, with an optional pump 41, is added under pressure to the liquor in line 24 in such a way that there is no relaxation, for example evaporation, to any significant degree. The mixture of black liquor in the line 24 is pumped 17 under pressure to the transfer line 18 for chips and preferably without relaxing the liquor.
    The liquor fed to the chip transfer line 18 increases the liquor / wood ratio (L / W) The L / W ratio in the impregnation vessel 12 and the digester 14 is typically lower than the L / W- in the line 18. the ratio in the line 18 due to the liquor which is added to the line and drawn off in the top separator.
    By using the liquor, for example the washing liquor in the line 40, to heat the chip slurry in the line 24, the amount of medium pressure steam supplied to the upper part of the digester can be significantly reduced, for example about 40%. Reducing the amount of medium pressure steam needed to heat the chips in the upper part of the kettle results in a corresponding reduction in the energy requirements of the pulp preparation process. The reduction of the amount of medium pressure steam injected into the boiler vessel also reduces the water condensate that forms in the boiler and thus the need to use evaporators is reduced. Although the invention has been described in connection with what may at present be considered the most practical and implied that it is intended to cover various preferred embodiments, the invention is not limited to the described embodiment, but on the contrary, modifications and equivalent embodiments fall within the scope of the invention. within the scope of the appended claims.
    权利要求:
    Claims (17)
    [1]
    A method of heating a pulp preparation system comprising an impregnation vessel and a chip slurry in a chemical boiling vessel, the method comprising the steps of: chips impregnated with a liquor in the impregnation vessel; the chips are transferred from the impregnation vessel to the upper plane of the boiler vessel; lye is removed from a washing strainer on the lower plane of the kettle, the peeled lye having a temperature which is substantially higher than the temperature of the chips in the impregnation vessel; a first portion of the lye deducted from the washing strainer on the lower plane of the kettle is added to the chips to be or which are being transferred from the impregnation vessel to the kettle, and the chips transferred are heated with the heat energy in the drawn lye; and a second portion of the liquor drawn from the washing strainer on the lower plane of the kettle flows to the upper area of the kettle.
    [2]
    The method of claim 1, wherein the first portion is about 30% - 80%, preferably about 50% - 80%, more preferably about 70% - 80%, and most preferably about 70% - 75%.
    [3]
    A method according to claim 1 or 2, wherein the temperature of the chips during the transfer does not exceed 120 ° C and the temperature of the liquor deducted from the washing strainer on the lower plane of the kettle is at least 130 ° C.
    [4]
    A method according to any one of the preceding claims, wherein the cooking vessel continuously transmits a flow of chips to the cooking vessel. the kettle is a continuous and a 10 15 20 25 30 35 534 130 21
    [5]
    A method according to any one of the preceding claims, wherein the chips are transferred to a top separator on the upper surface of the pan.
    [6]
    The method of claim 5, further comprising a step of removing liquor from the top separator and adding a portion of the liquor withdrawn from the top separator to the chips to be or which are being transferred from the impregnation vessel to the boiler vessel.
    [7]
    The method of claim 6, further comprising a step of mixing the liquor portion withdrawn from the top separator with the liquor withdrawn from the washing strainer on the lower surface of the pan before the stripped liquor is added to the chips to be transferred.
    [8]
    A method according to claim 6 or 7, wherein more than about 30%, preferably more than about half, more preferably more than about 70%, flows from the kettle to a heat recovery system. of the liquor subtracted from the top separator in
    [9]
    A method according to any one of claims 6 to 8, wherein below about 70%, preferably below about half, more preferably below about 30%, of the liquor withdrawn from the top separator is mixed with the liquor deducted from the washing strainer on the lower plane before the stripped liquor added to the chips.
    [10]
    A method according to any one of the preceding claims, wherein the proportion of lye in the chip slurry transferred is higher than the proportion of lye in the chip slurry in the impregnation vessel and in the boiler vessel.
    [11]
    11. ll. A method according to any one of the preceding claims, wherein the temperature of the stripped lye is at least 20 ° C higher than the temperature of the chips in the impregnation vessel. 10 15 20 25 30 35 534 '| 30 22
    [12]
    A method according to any one of the preceding claims, further comprising a step of recycling lye from an upper screen to the upper region of the pan.
    [13]
    A method according to any one of the preceding claims, wherein the peeled lye is added to the chips transferred from the impregnation vessel to the boiler vessel.
    [14]
    An apparatus for heating a chip slurry in a pulp preparation system comprising an impregnation vessel and a chemical cooking vessel, the apparatus comprising: a chip for transferring chips extending from the impregnation vessel to the cooking vessel, the chips in the chip transfer line flowing from the impregnation vessel to the boiler vessel; a wash strainer on the lower surface of the kettle, the liquor being drawn from the wash strainer on the lower plane, and a first from the wash strainer on the lower plane to the transfer line for chipping line extending chippings, the liquor subtracted from the wash strainer on the lower plane being fed to the transfer line for wood chips; wherein the first liquor conduit comprises a conduit directing a first portion of the liquor withdrawn from the wash strainer on the lower plane to the chip transfer line and a second portion of the liquor deducted from the wash strainer on the lower plane to a recirculation conduit extending to the boiler vessel; upper area.
    [15]
    An apparatus according to claim 14, wherein chips from the impregnation vessel to a top separator in the kettle, and the transfer line for extending a second liquor line extend from the top separator to the chip transfer line, the liquor deducted from the top separator flowing from the top separator to the transfer line for the ice. 534 130 23
    [16]
    The device of claim 14 or 15, wherein the first portion is about 30% - 80%, preferably about 50% - 80%, more preferably about 70% - 80%, and most preferably about 70% - 75%.
    [17]
    Device according to any one of claims 14 to 16, wherein the first line for lye extends to a section of the transfer line for chips in the vicinity of the impregnation vessel.
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    同族专利:
    公开号 | 公开日
    CA2599773C|2014-07-08|
    US8444809B2|2013-05-21|
    CN101435168A|2009-05-20|
    CA2599773A1|2008-12-25|
    RU2459025C2|2012-08-20|
    JP2009001952A|2009-01-08|
    BRPI0803706A2|2009-04-22|
    JP5220391B2|2013-06-26|
    RU2007147345A|2009-07-20|
    US20080314534A1|2008-12-25|
    CA2599773F|2008-12-25|
    SE0801458L|2008-12-26|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    US11/767,761|US8444809B2|2007-06-25|2007-06-25|Method and system for direct contact of hot liquor with wood chips in transfer circulation|
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