JP2009024322A - Impregnation vessel with convergence side relief and method for heat injection at convergence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for heating a chip impregnation layer of a continuous digesting apparatus. <P>SOLUTION: An impregnation vessel 10 includes a vessel container including an upper inlet for receiving a cellulosic material, a lower discharge port for discharging the cellulosic material from a discharge unit of the vessel container, a convergence section 22 in the vessel for passing a flow of the cellulosic material of the vessel, a cavity 34 locating between an internal wall of the vessel and the convergence section and having a lower opening for the cellulosic material in the vessel and an upper section shielded from the cellulosic material in the vessel, and an input port locating in the vessel and opening to the cavity and connectable to a source of hot liquid to be added to the cellulosic material in the vessel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention involves continuous digestion (for example, but not limited to, kraft or soda digestion process) of cellulosic material (eg, wood chips and non-wood raw materials such as annual grass and bagasse) to produce pulp. The present invention relates to a permeation tank used for manufacturing. In particular, the present invention relates to a method of supplying a high temperature liquid, such as a chemical or steam, to supply heat to the cellulosic material in the infiltration tank.

  The permeation tank is for pretreating the cellulose material before the cellulose material is supplied to the digester, for example. In the permeation tank, the cellulose material is immersed in a chemical solution and / or steam, and the cellulose material is heated. An example of a conventional tank suitable for an infiltration tank is disclosed in US Pat. No. 4,746,400, which includes a bottom scraper and includes a scraper for discharging cellulosic material from the tank. A tank having a lower hot liquid injection section is disclosed. Also, U.S. Pat. Nos. 5,500,083 and 5,628,873 disclose tanks having bottoms with one-dimensional and two-dimensional tapered areas in side relief type devices. Is currently sold as Diamondback (R) Chip Bin by Andritz, Inc. of Glenn Falls, New York.

  Cellulose material flows from the permeation tank to the digestion tank. The digester is generally operated at a higher temperature than the infiltration tank. Heat is supplied to the cellulosic material in a digester. Although the cellulose material is heated to some extent in the permeation tank, the cellulose material in the permeation tank is conventionally heated in the digestion tank later.

  If the temperature of the cellulose material is increased in the permeation tank, the amount of heat required to supply the cellulose material in the digestion tank can be reduced. When a high-temperature chemical is added to the downstream portion of the permeation tank, the added high-temperature chemical may form a high-temperature liquid flow that flows upward through the permeation tank. Such a flow can disrupt the desired uniform treatment of the cellulosic material flowing down the permeation tank. Therefore, it is not a prior art to add the high temperature liquid to the permeation tank.

The permeation tank provided by the present invention is:
A vessel containing an upper inlet for receiving the cellulosic material;
A lower discharge port for discharging the cellulose material from the discharge part of the tank container,
Tapered area inside the tank, allowing the cellulosic material flow in the tank to pass through
A cavity between the inner wall of the tank and the tapered area, having a lower opening to the cellulosic material in the tank and an upper part that is shielded from the flow of cellulosic material in the tank, and located in the tank It has an inlet port that opens to the cavity and can be connected to a source of high-temperature liquid added to the cellulose material in the tank.

  The tapered area may taper only in a single direction within the infiltration bath. The tapered section may also comprise a tapered wall comprising an upper section joined to the inner wall of the tub and a lower section disposed radially inward from the inner wall. The cavity is located between the inner wall of the tank and the tapered wall of the tapered area. The cavity can be located below the liquid level of the tank and can be arranged at the height of the central part of the tank divided into three equal parts. The source of the high temperature liquid is, for example, at a temperature of at least 120 degrees Celsius and can supply the liquid at a temperature higher than the discharge temperature of the cellulose material discharged from the permeation tank.

Other penetration tanks provided by the present invention are:
A vessel containing an upper inlet for receiving the cellulosic material;
A lower discharge port for discharging the cellulose material from the discharge part of the tank container,
One-dimensional tapered area inside the tank, allowing the cellulosic material flow in the tank to pass through
A cavity between the inner wall of the tank and the tapered area, having a lower opening for the cellulosic material in the tank and an upper part shielded from the cellulosic material in the tank, and a cavity located in the tank An inlet port that is open and can be connected to a source of high-temperature liquid added to the cellulose material in the tank, and the high-temperature liquid is supplied to the cavity at a temperature higher than the average temperature of the cellulose material in the tank Is provided.

According to the present invention, there is provided a method of heating a cellulosic material in a permeation tank with an internal tapered section. This method
Introducing a cellulosic material into the upper inlet port of the infiltration tank;
Adding hot liquid to the tank to form a liquid level at the top of the tank;
Heating the cellulose material with the heated liquid when the cellulose material flows down in the tank;
Narrowing the flow of cellulosic material into a funnel shape through an internal tapered area under the liquid level of the bath;
Introducing the hot liquid into the cavity behind the tapered area of the bath at a temperature higher than the temperature of the liquid to be heated;
Adding hot liquid from the cavity to the cellulosic material downstream of the internal tapered section;
The flow of cellulosic material downstream of the internal taper zone is heated with a hot liquid, and the cellulosic material is discharged from the cavity and a discharge port at the bottom of the tank below the internal taper zone.

  FIG. 1 is a schematic view of a permeation tank 10 for pretreatment of a cellulose material, referred to herein as a chip. The tank consists of a metal cylinder having a height of 100 feet (30 meters) or more and a diameter of 70 inches (2 meters) or more, and can process 700 metric tons (700 mtpd) of pulp per day. The chips can flow into, pass through, and flow out of the permeation tank continuously and simultaneously. Chips that have been pretreated for discharge from the infiltration tank 10 may flow into the upper inlet of the continuous digester 46.

  The chips are supplied from the chip source 12 to the permeation tank 10, but the chip source 12 may be a chip bin, a preliminary steam treatment tank, or simply a chip holding location (eg, when no chip bin is used). The infiltration tank 10 includes an upper tip inlet 14 that receives the tip and optionally in the form of a slurry containing a liquid. In the infiltration tank, a chip level 16 and a liquid level 18 are formed, and the chip level is usually above the liquid level. The liquid level 18 in the tank is formed by adding the heating liquid and / or the chip heating flash liquid (white liquid or black liquid) and / or steam from the above-mentioned supply source 19. The gas space 20 located above the bath liquid level 18 is preferably maintained at a temperature of about 100 degrees Celsius (° C.) and a pressure of atmospheric pressure. The heated liquid and / or steam flows directly into the gas space portion 20 of the permeation tank 10.

    A one-dimensional tapered area 22 is formed in the liquid region 24 below the liquid level 18 of the bath. Preferably, the tapered section 22 is located in the lower half of the tank and above the bottom rotating scraper 25 or other device for moving the chips in the direction of the bottom outlet 27. For example, the tapered area 22 is located at the height of the middle part of the tank, preferably below the center height of the tank and above the height of the lower part of the tank. To position.

  The one-dimensional tapered area 22 may be embodied as a hollow transition zone 26 having an open top 28 having a substantially circular cross section and an open bottom 30 having a substantially rectangular cross section. The tapered area 22 comprises a transition zone 26, which comprises two opposing side walls 29 that taper in a non-vertically tapered manner, the side wall 29 being at an angle to the vertical, generally An angle of about 20 ° to 35 °, preferably 25 ° to 30 ° may be formed. The side wall 29 may extend straight across the tub. The sidewalls can be straight (perpendicular or continuous) in a direction perpendicular to the axis of the vessel 10, in a direction parallel to the axis and along the transition zone 26.

  Opposite side ends of the side walls 29 can be joined to the tank inner wall 32. The open top 28 of the transition zone 26 may be curved to correspond to the vessel inner wall 32 and welded to the vessel inner wall 32 so that fluid does not leak completely between the vessel and the tapered section 22. One-dimensional tapered section structures used in the chip bath are disclosed in US Pat. Nos. 5,500,083 and 5,628,873. Support plates or ribs 31 may extend from the vessel wall 32 to the tapered wall 27 in the transition zone to support a tapered area within the vessel.

  FIG. 2 is a cross-sectional view of the permeation tank 10 as viewed from the top and shows the shape of the tapered area 22. The two opposing side walls 29 of the tapered section are tapered and may comprise an upper tapered side wall 50, a straight vertical side wall 52 and a lower tapered side wall 54. FIG. 2 shows a one-dimensional characteristic of the tapered area, where the bottom of the transition zone is narrower than the top 28 in one direction and as wide as the top 28 in a direction perpendicular thereto.

  A one-dimensional tapered area 22 in the transition zone facilitates the downward flow of the chip through the vessel and further through the transition zone. If there is a tapered area, the flow rate of the chips in the tank is adjusted, and the holding time of the chips in the tank 10 is properly maintained. Further, the one-dimensional tapered area 22 is less likely to clog the tip or cause a bridging phenomenon in the transition area than a conical tapered area that is tapered in two dimensions.

  A cavity 34 is formed between the tank inner wall 34 and the side wall (s) 29 of the transition area 26. The cavity 34 is a blocked area that exists behind the side wall 29 of the transition zone 26 and exists in the tank. The cavity 34 is blocked by a side wall from the downward flow of the chip in the tank. Since the cavity is located below the tapered transition zone sidewall 29, this sidewall prevents heat flow from moving up from the cavity and further up the transition zone 26. There are two cavities in the tank on opposite sides of the tank and one cavity behind each of the two side walls 29 of the tapered section 22.

  The cavity 34 provides a region where additional high temperature liquid, such as black liquor or white liquor, can be added without causing a liquid flush in the upper region of the bath 10. The hot liquid enters the cavity 34 and mixes with the chips that flow upward from the bottom of the transition zone outlet 30 into the cavity. The heat flow formed by the hot liquid cannot move up the tank. This is because the cavity is covered with a tapered side wall 29 in the transition region.

  The high temperature liquid is sent to the cavity 34 from the supply source of the high temperature liquid 42 (FIG. 1) via the pipe 40. The liquid 42 can be supplied from an excessively high temperature liquid in the cooking tank 46, but in particular, a high temperature cleaning liquid taken out from the lower part of the cooking tank 46. If sufficient excess black liquor cannot be obtained, the low pressure steam 48 can be used to heat the liquid 42 that is pumped through the pipe 40 to the cavity 34. In addition, other liquids having a sufficient amount of heat can be introduced into the cavity 34.

  The temperature of the liquid supplied to the cavity 34 is higher than the temperature of the gas phase space region 20 of the tank, and can be maintained at a temperature of, for example, 120 degrees Celsius. Therefore, the heated liquid and / or steam may be flashed if there is a flow into the gas phase space area 20. By introducing the high temperature liquid into the cavity, the side wall 29 can prevent the liquid from flowing upward.

  Hot liquid 42 from the liquid source, preferably black or white liquid, is introduced into the cavity 34, preferably at a height above the outlet 30 in the transition zone 26. Even if the liquid is introduced into the cavity, the flow of the chip flowing down in the tank is not disturbed. This is because the tip narrows in a funnel shape from the tapered area 22 and flows down away from the cavity 34. With the cavity 34, the hot liquid 42 flows into the tank in a relatively quiet flow, for example, almost stagnant. From this cavity, the high-temperature liquid gently diffuses into the flow of chips discharged from the discharge port 30 in the transition area.

  The liquid 42 added to the cavity 34 preferably has a temperature higher than the average temperature of the chips in the tank 10 and the temperature of the chips exiting the discharge port 38. The added liquid 42 heats the chip in the permeation tank 10. This heating is preferable when the chips are transported to the digester tank 46 which is normally operated at a higher temperature than the permeation tank.

  Even if the high temperature liquid 42 is introduced into the cavity 34, it does not interfere with the conventional discharge device 25, for example, a scraper or other mechanical devices. Scrapers and other mechanical devices include a valve system to help move the chips out of the tank outlet 38.

  The cavity 34 allows the liquid 42 to flow into the bath 10 without causing channeling, and a flow of heat occurs to rise in the chip in the bath. Another advantage obtained by adding the hot liquid 42 to the cavity 34 is that this effectively utilizes the excess hot liquid available at the pulp mill. As these liquids, liquids having a temperature of 100 ° C. or more can be used.

  Adding hot excess liquid to the infiltration bath 10 without the use of a tapered section 22 with sidewalls can cause channeling (an area where chip homogeneity and uniformity are compromised) with heat flow. When hot liquid is added directly from the tank inlet to the chip flow through the permeation tank, a heat flow occurs in the chip flow, which causes an upward flow of heat in the chip column, resulting in a chip flow. Heating can be inefficient.

  When the liquid is added to the cavity 34, the high temperature liquid can be mixed with other liquid in the cavity and diffused over a wide area with respect to the flow of chips discharged from the outlet 30 to the transition area. Furthermore, the hot liquid that enters the side wall of the tank and directly enters the flow of chips in the tank can interfere with the uniform movement and processing of the chips passing through the permeation tank. However, if the high temperature liquid is introduced into the cavity 34, the flow of the high temperature liquid is prevented from occurring in the flow of the chip, and the uniform movement of the chip flowing in the tank and the risk of disturbing the processing can be minimized. .

  FIG. 3 is a schematic side view of a portion of a permeation bath 50 with an orthogonal taper zone 52. FIG. 4 is a cross-sectional view looking down from the top of the infiltration tank 50 with the orthogonally tapered region 52. This orthogonal taper area comprises a transition zone 54 that narrows the flow path in the tank in two orthogonal directions. The flow path narrows from the overall cross-sectional area of the tank at the top of the transition zone 54 to a circular small cross-sectional area at the outlet 56 of the tapered area. The transition region 54 preferably includes a diamond-shaped side panel 58 and a curved side panel 60 connecting them. A hot liquid inlet 62 through which hot liquid, eg, hot chemical and / or steam 64 can be introduced, is an annular cavity 66 between the inner wall 68 of the vessel 50 and the outer surface of the side panels 58, 60 of the tapered section 52. Placed in. This cavity provides a tip that flows down through the tank and a permeation region that exists outside the direct flow path of the liquid. The chip and liquid mix with the stream of hot liquid flowing down from the cavity as it exits from the outlet 54 of the tapered section 52. With this high-temperature liquid, the chip further flows down in the tank 50, reaches the discharge device, for example, a scraper, and finally reaches the outlet 72 of the tank, thereby heating the chip.

  Although the present invention has been described with respect to what is presently considered to be the most practical and preferred embodiments, the invention is not limited to the disclosed embodiments, but rather, on the contrary, is within the scope of the claims. It also encompasses a wide variety of modifications or equivalent techniques involved.

It is a schematic side view of an infiltration tank provided with a unidirectional taper area. It is sectional drawing when the bottom is seen from the top part of an infiltration tank provided with a unidirectional taper area. It is a schematic side view of an infiltration tank provided with a taper area of an orthogonal direction. It is sectional drawing when the bottom is seen from the top part of the penetration tank provided with the taper area of an orthogonal direction.

Claims (23)

A vessel containing an upper inlet for receiving the cellulosic material;
A lower discharge port for discharging the cellulose material from the discharge part of the tank container,
Tapered area inside the tank, allowing the cellulosic material flow in the tank to pass through
A cavity located between the inner wall of the tank and the tapered area, having a lower opening for the cellulose material in the tank and an upper part that is shielded from the flow of cellulose material in the tank, and located in the tank An infiltration tank comprising an inlet port that is open to the cavity and is connectable to a source of high-temperature liquid added to the cellulose material in the tank.   The permeation tank according to claim 1, wherein the tapered area is tapered in a single direction in the tank.   The permeation tank according to claim 1, wherein the tapered area is tapered in the orthogonal direction in the tank.   2. The infiltration tank according to claim 1, wherein the tapered area includes a tapered wall having an upper area joined to the inner wall of the tank and a lower area disposed radially inward from the inner wall, and the cavity portion is provided. An infiltration tank, which is located between the inner wall of the tank and the tapered wall of the tapered area.   The infiltration tank according to claim 1, wherein the tapered area and the cavity are located below the liquid level of the tank.   The permeation tank according to claim 1, wherein the supply source of the high temperature liquid supplies the high temperature liquid at a temperature higher than a discharge temperature of the cellulose material discharged from the permeation tank.   The infiltration tank according to claim 1, wherein the source of the high temperature liquid supplies the high temperature liquid at a temperature of at least 120 degrees Celsius. A vessel containing an upper inlet for receiving the cellulosic material;
A lower discharge port for discharging the cellulose material from the discharge part of the tank container,
One-dimensional tapered area inside the tank, allowing the cellulosic material flow in the tank to pass through
A cavity between the inner wall of the tank and the tapered area, having a lower opening for the cellulosic material in the tank and an upper part that is shielded from the flow of cellulosic material in the tank, and a cavity located in the tank The high temperature liquid is added to the cavity at a temperature higher than the average temperature of the cellulose material in the tank. An infiltration tank comprising an inlet port.   9. The infiltration tank according to claim 8, wherein the one-dimensional tapered area comprises a tapered wall having an upper area joined to the inner wall of the tank and a lower area arranged radially inward from the inner wall, An infiltration tank characterized in that the portion is located between the inner wall of the tank and the tapered wall of the tapered area.   9. The infiltration tank according to claim 8, wherein the tapered area and the cavity are located below the liquid level of the tank.   The permeation tank according to claim 8, wherein the supply source of the high temperature liquid supplies the high temperature liquid at a temperature higher than a discharge temperature of the cellulose material discharged from the tank.   9. The infiltration tank according to claim 8, wherein the source of the high temperature liquid supplies the high temperature liquid at a temperature of at least 120 degrees Celsius. In a method of heating cellulose material in a permeation tank with an internal tapered area,
Introducing a cellulosic material into the upper inlet port of the infiltration tank;
Adding heated liquid to the tank to form a liquid level at the top of the tank;
Heating the cellulose material with the heated liquid when the cellulose material flows down in the tank;
Detecting the flow of cellulosic material in the tank passing through the internal tapered area under the liquid level;
Introducing a high temperature liquid into the cavity behind the tapered section in the bath and introducing the high temperature liquid into the cavity at a temperature higher than the temperature of the liquid to be heated;
Adding hot liquid from the cavity to the flow of cellulosic material downstream of the internal taper zone;
Heating the cellulosic material stream downstream of the internal taper zone with the hot liquid, and discharging the cellulosic material from a discharge port located at the bottom of the tank below the cavity and the internal taper zone. Method.   14. The method according to claim 13, wherein the cellulosic material is continuously introduced into the tank and continuously discharged from the tank.   14. The method of claim 13, wherein the tapered area tapers in a single direction within the bath.   14. The method of claim 13, wherein the tapered section comprises a tapered wall having an upper area joined to the tank inner wall and a lower area located radially inward from the inner wall, wherein the cavity is a tank. A permeation tank, which is located between the inner wall of the taper and the tapered wall of the tapered section, and the high-temperature liquid added to the cavity is blocked by the tapered wall.   14. The method of claim 13, wherein the tapered section tapers in an orthogonal direction and the flow narrows in a funnel shape from the tapered section toward the circular outlet.   14. The method according to claim 13, wherein the high temperature liquid is added to the cavity at a temperature higher than the discharge temperature of the cellulose material discharged from the tank.   14. The method of claim 13, wherein the hot liquid is at a temperature of at least 120 degrees Celsius when added to the cavity.   14. The method of claim 13, further comprising the step of transferring the discharged cellulosic material to a digester.   21. A method according to claim 20, wherein the hot liquor comprises hot black liquor extracted from a digester.   21. A method according to claim 20, wherein the hot liquor comprises hot black liquor extracted from the lower region of the digester. 14. The method of claim 13, further comprising the step of supplying the introduced cellulosic material from a tip bin.