Turpentine recovery system of pulping and paper-making factory

Abstract

The invention relates to the technical field of pulping and paper-making factory equipment, and particularly discloses a turpentine recovery system of a pulping and paper-making factory, which comprises an evaporation heavy-dirt condensate water tank, the lower part of the evaporation heavy-dirt condensate water tank is connected with a heavy-dirt water pump through a pipeline, and the heavy-dirt water pump is connected with a condensate water cooler through a pipeline; the condensate water cooler is connected with the bottom of the turpentine separator through a pipeline, an overflow pipe is arranged at the top of the turpentine separator, a regulating valve is arranged on the overflow pipe, and the overflow pipe is connected with the turpentine tank through a pipeline; the bottom of the turpentine separator is connected with a U-shaped pipe, the liquid outlet end of the U-shaped pipe is connected with the heavy-pollution condensate water tank, and a U-shaped elbow of the U-shaped pipe is higher than the ground relative to the liquid inlet end and the liquid outlet end of the U-shaped pipe, so that turpentine can be separated through an overflow pipe at the top of the turpentine separator, but water cannot reach the top of the tank. According to the invention, turpentine in the evaporation heavy sewage tank can be separated, and the evaporation efficiency of the evaporation system is improved.

Description

Technical Field

[0001] The present invention relates to the field of equipment in pulp and paper mills, and particularly to a turpentine recovery system for pulp and paper mills. Background Art

[0002] Turpentine is a mixture of various components. The types and amounts of specific components depend on the type of pine tree, the geographical location of the tree, and the season in which the tree is harvested. Turpentine produced in the United States mainly consists of α-pinene (75% to 85%) and varying amounts of β-pinene (up to 3%), camphene (4% to 15%), limonene (dipentene, 5% to 15%), 3-carene, and terpinolene. Turpentine is the name given to many semi-fluid oleoresins obtained from coniferous trees. The substances obtained from these trees consist of 75% to 90% resin and 10% to 25% oil. When distilled, it produces turpentine (C 10 H 6 ). Turpentine is a mixture of terpenes and essential oils, and its percentage varies depending on geographical location, tree species, and the distillation process. After the trees in the pulp and paper mill are cooked, black liquor is formed. A large amount of heavily polluted condensate is generated during the concentration of the black liquor. The highly concentrated odor from cooking passes through a cyclone separator and then the gas is cooled to 85°C by a condenser. The condensed liquid goes to the cooking heavy sewage tank, and the discharged liquid of the cooking heavy sewage condensate goes to the heavy sewage condensate tank in the evaporation section. The highly concentrated odor that has not been condensed goes to the condenser to be cooled to 50°C and then goes to the highly concentrated odor collection system. When the raw material for cooking is pine wood, the heavy sewage condensate tank in the evaporation section may contain turpentine (boiling point 150 - 170°C, density 860 - 875 kg / m 3 ). When the system operates for a long time, turpentine may accumulate in the tank, forming a stable "turpentine + water" two-phase layer, which is not conducive to the long-term operation of the evaporation system. Usually, crude sulfate turpentine is usually contaminated to varying degrees by sulfides, and its market value is usually very high, so it is preferably sold rather than burned. If the sulfide content is too high or the quality of the terpene component is poor, incineration may be the only feasible disposal method. Summary of the Invention

[0003] The purpose of the present invention is to provide a turpentine recovery system for pulp and paper mills, which can separate the turpentine in the evaporation heavy sewage tank, improve the evaporation efficiency of the evaporation system, and save the steam consumption required for evaporation.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A turpentine recovery system for a pulp and paper mill, comprising an evaporation heavy pollution condensate tank storing heavy pollution condensate. The lower part of the evaporation heavy pollution condensate tank is connected to a heavy sewage pump through a pipeline. The heavy sewage pump is connected to a condensate cooler through a pipeline. The condensate cooler is connected to the bottom of a turpentine separator through a pipeline. An overflow pipe is arranged at the top of the turpentine separator. A regulating valve is arranged on the overflow pipe. The overflow pipe is connected to a turpentine oil tank through a pipeline;

[0006] A U-shaped pipe is connected to the bottom of the turpentine separator. A control valve is arranged on the U-shaped pipe. The liquid outlet end of the U-shaped pipe is connected to a heavy pollution condensate tank. The U-shaped elbow of the U-shaped pipe is higher than the liquid inlet end and the liquid outlet end of the U-shaped pipe from the ground. The height difference between the lowest point of the inner wall of the U-shaped elbow and the bottom of the turpentine separator is H 3 , H 3 satisfies the following conditions with the lower limit of the oil-water interface in the turpentine separator:

[0007] H 1 *ρ 松 +H 2 ρ 水 =H 3 ρ 水 ,

[0008] H 2 is the height difference between the lower limit of the oil-water interface in the turpentine separator and the bottom of the turpentine separator, H 1 is the height difference between the lower limit of the oil-water interface in the turpentine separator and the top of the turpentine separator, ρ 松 is the density of turpentine, ρ 水 is the density of water;

[0009] When the turpentine separator is filled with liquid and the oil-water interface in the turpentine separator is not greater than the lower limit of the oil-water interface, the water phase cannot flow into the heavy pollution condensate tank through the U-shaped pipe.

[0010] Optionally, the lower limit of the oil-water interface in the turpentine separator is the lower limit of the liquid level sight glass window on the turpentine separator.

[0011] Optionally, the U-shaped pipe includes a first horizontal pipe connected to the liquid outlet end at the bottom of the turpentine separator, a first vertical pipe extending upward after bending from the other end of the first horizontal pipe, a second horizontal pipe connected to the first vertical pipe, and a second vertical pipe extending downward and then extending after bending from the other end of the second horizontal pipe. The second vertical pipe is connected to the heavy pollution condensate tank through a horizontal pipe.

[0012] Furthermore, the connections of the first horizontal pipe, the first vertical pipe, the second horizontal pipe, and the second vertical pipe all adopt rounded corner transitions.

[0013] Optionally, a heavy sewage pump is connected to the lower part of the heavy pollution condensate tank through a pipeline, and the top of the heavy pollution condensate tank is connected to the high-concentration odor system through a pipeline.

[0014] Optionally, the top of the turpentine oil tank is connected to the high-concentration odor system through a pipeline.

[0015] Optionally, the height difference between the highest point of the inner wall of the U-shaped elbow and the bottom of the turpentine separator is H 4 , and the upper limit of the oil-water interface in the turpentine separator is the upper limit of the upper liquid level sight glass window of the turpentine separator, H 4 and the upper limit of the oil-water interface in the turpentine separator satisfy the following conditions:

[0016] H 5 *ρ 松 +H 6 ρ 水 =H 4 ρ 水 ,

[0017] H 6 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the bottom of the turpentine separator, H 5 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the top of the turpentine separator, ρ 松 is the density of turpentine, ρ 水 is the density of water.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] 1. The turpentine in the evaporation heavy sewage tank can be separated, the evaporation efficiency of the evaporation system can be improved, and the steam consumption required for evaporation can be saved.

[0020] 2. The water content in the separated turpentine is very small, and it can be mixed with the methanol extracted from SOG as the fuel of the incinerator, saving the consumption of natural gas or light diesel oil of the incinerator.

[0021] 3. The separation system can easily separate the turpentine, but when the turpentine separator is filled with liquid and the oil-water interface in the turpentine separator is not greater than the lower limit of the oil-water interface, the water phase cannot flow into the heavy pollution condensate tank through the U-shaped pipe.

[0022] 4. The lower limit of the oil-water interface in the turpentine separator is the lower limit of the sight glass window of the upper liquid level in the turpentine separator, and the upper limit of the oil-water interface in the turpentine separator is the upper limit of the sight glass window of the upper liquid level in the turpentine separator. In this way, within the visible range of the sight glass window of the upper liquid level in the turpentine separator, it can be avoided that when the lower limit of the oil-water interface in the turpentine separator is lower than the lower limit of the sight glass window of the upper liquid level in the turpentine separator, the oil flows into the heavy pollution condensate tank through the U-shaped pipe, or when the upper limit of the oil-water interface in the turpentine separator is higher than the upper limit of the sight glass window of the upper liquid level in the turpentine separator, the water enters the turpentine tank through the overflow pipe at the top of the turpentine separator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0024] Figure 1 is a schematic diagram of the system of the present invention;

[0025] Figure 2 is a schematic diagram of the turpentine separator and the U-shaped pipe of the present invention;

[0026] Figure 3 is a schematic diagram corresponding to the height of the oil-water interface in the turpentine separator and the height of the U-shaped pipe of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] A turpentine recovery system for a pulp and paper mill, as Figure 1As shown in the figure, it includes an evaporation heavy pollution condensate tank 1 storing heavy pollution condensate water. The lower part of the evaporation heavy pollution condensate tank 1 is connected to a heavy sewage pump 2 through a pipeline. The heavy sewage pump 2 is connected to a condensate cooler 3 through a pipeline. The condensate cooler 3 is connected to the bottom of a turpentine separator 4 through a pipeline. An overflow pipe 4.1 is provided at the top of the turpentine separator 4, and a regulating valve is provided on the overflow pipe 4.1. The overflow pipe 4.1 is connected to a turpentine oil tank 7 through a pipeline. The top of the turpentine oil tank 7 is connected to a high-concentration odor system through a pipeline, and the bottom of the turpentine oil tank 7 is connected to a turpentine oil pump 8 through a pipeline. The bottom of the turpentine separator 4 is connected to a U-shaped pipe 10, a control valve is provided on the U-shaped pipe 10, and the liquid outlet end of the U-shaped pipe 10 is connected to a heavy pollution condensate water tank 5. The lower part of the heavy pollution condensate water tank 5 is connected to the heavy sewage pump 2 through a pipeline, and the top of the heavy pollution condensate water tank 5 is connected to a high-concentration odor system through a pipeline.

[0030] As Figure 2 shown, the U-shaped pipe 10 of the present invention includes a first horizontal pipe 10.1 connected to the liquid outlet end at the bottom of the turpentine separator, a first vertical pipe 10.2 extending upward and bending after the other end of the first horizontal pipe 10.1, a second horizontal pipe 10.3 connected to the first vertical pipe 10.2, and a second vertical pipe 10.4 extending downward and bending after the other end of the second horizontal pipe 10.3. The tail of the second vertical pipe 10.4 is connected to a horizontal pipe, and the horizontal pipe is connected to the heavy pollution condensate water tank 5. Further, the joints of the first horizontal pipe 10.1, the first vertical pipe 10.2, the second horizontal pipe 10.3, and the second vertical pipe 10.4 all adopt rounded corners for transition. In the present invention, the heavy pollution condensate water in the evaporation heavy pollution condensate tank 1 is transported by the heavy sewage pump 2 to the condensate water cooler 3 to be cooled to 55°C, and then enters the turpentine separator 4 for separation through the density difference. Since the density of oil is smaller than that of water, the oil layer on the upper layer of the turpentine separator 4 comes out from the top and enters the turpentine oil tank 7 for temporary storage, and then is transported away by the turpentine oil pump 8. The water layer on the lower layer of the turpentine separator 4 comes out from the bottom and enters the heavy pollution condensate water pump tank 5, and then is pumped back to the heavy sewage tank in the evaporation section by the heavy sewage pump 2.

[0031] The lower limit of the oil-water interface in the turpentine separator is the lower limit of the upper liquid level sight glass window of the turpentine separator: oil-water interface a;

[0032] The upper limit of the oil-water interface in the turpentine separator is the upper limit of the upper liquid level sight glass window of the turpentine separator: oil-water interface c;

[0033] Through the height difference H between the lower surface of the second horizontal pipe 10.3 of the U-shaped pipe 10 (i.e., the highest point a' of water) and the bottom of the turpentine separator 4 3 , when there is more oil phase and less water phase in the turpentine separator 4, it prevents the water phase from flowing into the heavy pollution condensate water tank 5 through the second horizontal pipe 10.3, and prevents the turpentine from being entrained in the water phase.

[0034] As Figure 3 shown, the specific principle is as follows: When the turpentine separator 4 is filled with liquid and the oil-water interface in the turpentine separator 4 is lower than or equal to the height of point a, the height difference between the upper surface of the water phase in the turpentine separator 4 and the bottom of the turpentine separator 4 is H 1 , and the height difference between the upper surface of the water phase in the turpentine separator 4 and the top of the turpentine separator 4 is H 2 .

[0035] According to the principle that the product of the density and height of the liquid in the turpentine separator 4 (the static pressure of the mixed liquid) is equal to the product of the density and height of the liquid in the U-shaped tube 10 (the static pressure of water).

[0036] H 1 *0.867 + H 2 = H 3 ; 0.867 is the approximate density value of turpentine.

[0037] If H 1 increases and H 2 decreases, it is equivalent to an increase in the oil phase and a decrease in the water phase in the turpentine separator 4, resulting in a decrease in the static pressure of the mixed liquid in the turpentine separator 4, leading to a decrease in the static pressure of the water phase in the U-shaped tube 10. Therefore, the height of the water phase in the U-shaped tube 10 is lower than the lower surface of the second horizontal tube 10.3, and the water phase cannot flow into the heavy pollution condensate tank 5 through the second horizontal tube 10.3, preventing the entrainment of turpentine in the water phase.

[0038] If the turpentine separator 4 is filled with liquid and there is less oil phase and more water phase in the turpentine separator 4, the oil-water interface in the turpentine separator 4 is greater than the height of point a, causing H 1 to decrease and H 2 to increase. The static pressure of the mixed liquid in the turpentine separator 4 increases, resulting in an increase in the static pressure of the water phase in the U-shaped tube 10. Therefore, the height of the water phase in the U-shaped tube 10 is higher than the lower surface of the second horizontal tube 10.3, and the water phase flows into the heavy pollution condensate tank 5 through the second horizontal tube 10.3, avoiding the entrainment of the water phase when discharging the oil phase from the overflow pipe 4.1.

[0039] That is, the principle is: The height difference between the highest point on the inner wall of the U-shaped elbow and the bottom of the turpentine separator is H 4 , and the upper limit of the oil-water interface in the turpentine separator is the upper limit of the liquid level sight glass window of the turpentine separator. H 4 and the upper limit of the oil-water interface in the turpentine separator satisfy the following conditions:

[0040] H 5 *ρ 松 + H 6 ρ 水 = H 4 ρ水 ,

[0041] H 6 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the bottom of the turpentine separator, H 5 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the top of the turpentine separator, ρ 松 is the density of turpentine, ρ 水 is the density of water.

[0042] If the turpentine separator 4 is filled with liquid and the upper limit of the oil-water interface in the turpentine separator is higher than the upper limit of the liquid level sight glass window of the turpentine separator, it can prevent water from entering the turpentine tank through the overflow pipe of the turpentine separator in an invisible state.

[0043] During use, since an overflow pipe 4.1 is provided at the top of the turpentine separator 4, when the turpentine separator 4 is filled with liquid, the liquid overflows from the overflow pipe 4.1. At this time, the control valve on the U-shaped pipe 10 is opened to make the water phase in the turpentine separator 4 flow back into the U-shaped pipe. When the turpentine separator 4 is completely filled with liquid, ensure that when the water in the turpentine separator 4 is at a height lower than or equal to point a at the oil-water interface in the turpentine separator 4, the water cannot be discharged from the top of the turpentine separator 4.

[0044] It also ensures that the oil-water interface of the mixed liquid is within the visible range of the sight glass window of the turpentine separator, and the oil will not flow into the heavy pollution condensate tank, and the water will not flow into the overflow pipe.

[0045] In the present invention, the heavy pollution condensate stored in the evaporation heavy pollution condensate tank 1 is transported by the heavy pollution condensate pump 2 to the condensate cooler 3 to be cooled to 55°C, and then enters the turpentine separator 4 for separation by density difference. The turpentine and the heavy pollution condensate are allowed to stand and separate in the turpentine separator 4. Since the density of turpentine is smaller than that of water, the turpentine layer on the upper layer of the turpentine separator 4 flows out from the top overflow pipe 4.1 and enters the turpentine tank 7 for temporary storage, and then is transported by the turpentine pump 8 to be mixed with the methanol extracted from SOG as the fuel of the incinerator to save the consumption of natural gas or light diesel oil in the incinerator, or can be temporarily stored and sold externally; when it is found that turpentine overflows from the top of the turpentine separator 4, the control valve on the U-shaped pipe 10 is opened, and the heavy pollution condensate at the lower layer of the turpentine separator 4 flows out from the bottom and is pumped back to the evaporation heavy pollution condensate tank 1 in the evaporation section by the heavy pollution condensate pump 2; the high-concentration odor flowing out from the top of the heavy pollution condensate tank 5 and the turpentine tank 7 is sent to the high-concentration odor system for treatment.

[0046] The above is only the specific implementation manner in the present invention, but the protection scope of the present invention is not limited thereto. Any transformation or replacement that can be understood by those familiar with the technology within the technical scope disclosed by the present invention should be covered within the scope of the present invention.

Claims

1. A turpentine recovery system for a pulp and paper mill, comprising an evaporative heavy-polluted condensate water tank storing heavy-polluted condensate water, wherein the lower part of the evaporative heavy-polluted condensate water tank is connected to a heavy-polluted water pump through a pipeline, the heavy-polluted water pump is connected to a condensate water cooler through a pipeline, and the condensate water cooler is connected to the bottom of a turpentine separator through a pipeline, characterized in that: An overflow pipe is arranged on the top of the turpentine separator, a regulating valve is arranged on the overflow pipe, and the overflow pipe is connected to the turpentine tank through a pipeline; The bottom of the turpentine separator is connected to a U-shaped tube, a control valve is arranged on the U-shaped tube, the liquid outlet end of the U-shaped tube is connected to the heavy pollution condensed water tank, the U-shaped elbow of the U-shaped tube is higher than the liquid inlet end and the liquid outlet end of the U-shaped tube from the ground, the height difference between the lowest point of the inner wall of the U-shaped elbow and the bottom of the turpentine separator is H3, and H3 and the lower limit of the oil-water interface in the turpentine separator meet the following conditions: H1*p 松 +H2p 水 =H3ρ 水 , H2 is the height difference between the lower limit of the oil-water interface in the turpentine separator and the bottom of the turpentine separator, H1 is the height difference between the lower limit of the oil-water interface in the turpentine separator and the top of the turpentine separator, ρ 松 is the density of turpentine, ρ 水 is the density of water; When the turpentine separator is filled with liquid and the oil-water interface in the turpentine separator is not greater than the lower limit of the oil-water interface, the water phase cannot flow into the heavy polluted condensate tank through the U-shaped tube.

2. The turpentine recovery system for a pulp and paper mill according to claim 1, characterized in that: The lower limit of the oil-water interface in the turpentine separator is the lower limit of the liquid level sight glass window on the turpentine separator.

3. The turpentine recovery system for a pulp and paper mill according to claim 1, characterized in that: The U-shaped tube includes a first horizontal tube connected to the liquid outlet end at the bottom of the turpentine separator, a first vertical tube extending after bending upward from the other end of the first horizontal tube, a second horizontal tube connected to the first vertical tube, and a second vertical tube bending and extending downward from the other end of the second horizontal tube, wherein the second vertical tube is connected to a heavy pollutant condensate tank via a horizontal tube.

4. The turpentine recovery system for a pulp and paper mill according to claim 3, characterized in that: The connections between the first section horizontal pipe, the first section vertical pipe, the second section horizontal pipe and the second section vertical pipe are all connected by rounded corners.

5. The turpentine recovery system for a pulp and paper mill according to claim 1, characterized in that: The lower part of the heavy sewage condensate water tank is connected to a heavy sewage pump through a pipeline, and the top of the heavy sewage condensate water tank is connected to a high-concentration odor removal system through a pipeline.

6. The turpentine recovery system for a pulp and paper mill according to claim 1, characterized in that: The top of the turpentine tank is connected to a high-concentration odor removal system through a pipeline.

7. The turpentine recovery system for a pulp and paper mill according to claim 1, characterized in that: The height difference between the highest point of the inner wall of the U-shaped elbow and the bottom of the turpentine separator is H4, the upper limit of the oil-water interface in the turpentine separator is the upper limit of the liquid level sight glass window on the turpentine separator, and H4 and the upper limit of the oil-water interface in the turpentine separator meet the following conditions: H5*p 松 +H6p 水 =H4ρ 水 , H6 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the bottom of the turpentine separator, H5 is the height difference between the upper limit of the oil-water interface in the turpentine separator and the top of the turpentine separator, ρ 松 is the density of turpentine, ρ 水 is the density of water.

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