Liquid level meter mounting structure on liquid chamber of bamboo pulp black liquor falling film evaporator

Abstract

The utility model discloses a liquidometer mounting structure on a liquid chamber of a bamboo pulp black liquor falling-film evaporator, which comprises the bamboo pulp black liquor falling-film evaporator and the liquid chamber of the bamboo pulp black liquor falling-film evaporator at the lower part of the bamboo pulp black liquor falling-film evaporator, and a reducing liquid outlet pipe is arranged at the lower part of the liquid chamber of the bamboo pulp black liquor falling-film evaporator. A left side differential pressure type liquid level meter and a right side differential pressure type liquid level meter are respectively mounted on the left side and the right side of the liquid chamber of the bamboo pulp black liquor falling film evaporator. A left gas-phase diaphragm of the left differential pressure type liquid level meter is installed on the upper portion of the left side of the liquid chamber of the black liquor falling film evaporator, a left liquid-phase diaphragm is arranged on the left side of the lower portion of the reducing liquid outlet pipe, the left gas-phase diaphragm and the left liquid-phase diaphragm are connected to the left pressure transmitter through a left pressure guide pipe, and the right differential pressure type liquid level meter is installed corresponding to the left side. The structure can reduce the accumulation of impurities and scale blocks in the black liquor on the surface of the liquid phase membrane, prevent the liquid level meter from distortion caused by instability of the black liquor when the black liquor passes through the liquid outlet pipe, and guarantee the stable operation of a black liquor evaporation system.

Description

Technical Field

[0001] The utility model relates to the technical field of alkali recovery black liquor evaporators, in particular to a liquid level gauge installation structure on a liquid chamber of a bamboo pulp black liquor falling film evaporator. Background Art

[0002] In industrial production, approximately 50% of the fiber raw materials dissolve in the cooking liquor during the kraft pulping process. The waste pulping liquor separated by washing is called black liquor. This black liquor is sent to the alkali recovery and evaporation section, where it is gradually concentrated in a multi-effect falling film evaporator to a high-concentration black liquor before being sent to the alkali furnace for combustion.

[0003] Black liquor consists of water and solids. The solids have a complex composition, primarily consisting of organic and inorganic matter. Organic matter accounts for approximately 70%, primarily lignin, hemicellulose, cellulose degradation products, and organic acids; inorganic matter accounts for approximately 30%, primarily free sodium hydroxide, sodium sulfide, sodium carbonate, sodium sulfate, organic sodium salts, and silica. Bamboo pulp black liquor has unique characteristics. Compared to wood pulp black liquor of the same concentration, bamboo pulp black liquor processed in a falling film evaporator has a higher viscosity and silicon content, and is highly susceptible to scaling at high concentrations.

[0004] The vapor phase diaphragm of the current differential pressure level gauge is installed above the liquid level of the black liquor stored in the falling film evaporator's liquid chamber, while the liquid phase diaphragm is installed on the elliptical curved bottom of the falling film evaporator's liquid chamber. During the operation of the falling film evaporator, due to the complex composition of the black liquor, the accumulation of debris or scale in the black liquor on the lower liquid phase diaphragm surface of the differential pressure level gauge has repeatedly caused liquid level distortion. Once the level gauge is distorted, the evaporation system must be shut down and the falling film evaporator drained for maintenance. The startup and shutdown of the falling film evaporator generally requires a long time, which greatly tests the buffering capacity of the entire alkali recovery system and significantly increases production and operating costs. Utility Model Content

[0005] The purpose of the utility model is to provide a liquid level gauge installation structure on the liquid chamber of a bamboo pulp black liquor falling film evaporator, so as to solve the problem that the lower liquid phase diaphragm of the existing bamboo pulp falling film evaporator differential pressure type liquid level gauge is easily distorted due to the accumulation of debris or scale in the black liquor on the diaphragm surface.

[0006] The technical solution adopted by the utility model is a liquid level gauge installation structure on the bamboo pulp black liquor falling film evaporator liquid chamber, which includes a bamboo pulp black liquor falling film evaporator and a bamboo pulp black liquor falling film evaporator liquid chamber below it, and differential pressure liquid level gauges are installed on both sides of the bamboo pulp black liquor falling film evaporator liquid chamber.

[0007] Preferably, a variable-diameter liquid outlet pipe is provided at the lower part of the liquid chamber of the above-mentioned bamboo pulp black liquor falling film evaporator, and the differential pressure liquid level gauge includes a left differential pressure liquid level gauge and a right differential pressure liquid level gauge. The left differential pressure liquid level gauge includes a left gas phase diaphragm, a left liquid phase diaphragm, a left pressure pipe and a left pressure transmitter. The left gas phase diaphragm is installed on the upper left side of the liquid chamber of the black liquor falling film evaporator, and the left liquid phase diaphragm is located on the left side of the lower part of the variable-diameter liquid outlet pipe. The left gas phase diaphragm and the left liquid phase diaphragm are connected to the left pressure transmitter through the left pressure pipe; the right differential pressure liquid level gauge includes a right gas phase diaphragm, a right liquid phase diaphragm, a right pressure pipe and a right pressure transmitter. The right gas phase diaphragm is installed on the upper right side of the liquid chamber of the black liquor falling film evaporator, and the right liquid phase diaphragm is located on the right side of the lower part of the variable-diameter liquid outlet pipe. The right gas phase diaphragm and the right liquid phase diaphragm are connected to the right pressure transmitter through the right pressure pipe.

[0008] Preferably, the above-mentioned variable diameter liquid outlet pipe includes an upper thick pipe, the upper part of the upper thick pipe is connected to the liquid chamber of the black liquor falling film evaporator, and the lower part is connected to the variable diameter pipe, the diameter of the variable diameter pipe gradually decreases from top to bottom to two-thirds of the upper part, and the lower part of the variable diameter pipe is connected to the lower thin pipe, and the left liquid phase diaphragm and the right liquid phase diaphragm are respectively installed on the left and right sides of the lower thin pipe.

[0009] Preferably, the left gas phase membrane and the right gas phase membrane are installed above the liquid level of the black liquor stored in the black liquor falling film evaporator.

[0010] Preferably, the upper portion of the liquid chamber of the above-mentioned bamboo pulp black liquor falling film evaporator is cylindrical, and the lower portion is elliptical arc-shaped.

[0011] Preferably, the differential pressure level gauge and the variable diameter liquid outlet pipe are both made of corrosion-resistant stainless steel.

[0012] Compared with the existing technology, the beneficial effect of the present invention is that two sets of differential pressure level gauges are installed on the left and right sides of the liquid chamber of the bamboo pulp black liquor falling film evaporator, and the liquid phase diaphragm of the differential pressure level gauge is installed on the lower thin pipe of the reduced diameter liquid outlet pipe at the lower part of the falling film evaporator liquid chamber, which can reduce the accumulation of debris and scale in the black liquor on the surface of the liquid phase diaphragm; by reducing the diameter of the lower liquid outlet pipe of the falling film evaporator liquid chamber and installing the liquid phase diaphragm on the lower thin pipe to reduce the disturbance of the differential pressure level gauge when the black liquor passes through the liquid outlet pipe, it can effectively prevent the liquid level gauge from being distorted due to the instability of the black liquor when passing through the liquid outlet pipe, thereby ensuring the stable operation of the black liquor evaporation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the overall structure of the utility model;

[0014] Figure 2 This is a schematic diagram of the liquid chamber structure of the black liquor falling film evaporator;

[0015] Figure 3Schematic diagram of the structure of the variable diameter liquid outlet pipe;

[0016] Markings in the figure: 1. Black liquor falling film evaporator, 2. Left gas phase diaphragm, 3. Right gas phase diaphragm, 4. Left liquid phase diaphragm, 5. Right liquid phase diaphragm, 6. Left pressure transmitter, 7. Reducer liquid outlet pipe, 8. Black liquor falling film evaporator liquid chamber, 9. Right pressure transmitter, 10. Reducer pipe, 11. Left differential pressure level gauge, 12. Right differential pressure level gauge, 13. Upper thick pipe, 14. Lower thin pipe, 15. Left pressure guide pipe, 16. Right pressure guide pipe. DETAILED DESCRIPTION

[0017] The present invention will be further explained below with reference to the accompanying drawings to facilitate better understanding by those skilled in the art.

[0018] Example 1

[0019] like Figure 1-3 As shown, the liquid level gauge installation structure on the bamboo pulp black liquor falling film evaporator liquid chamber includes the bamboo pulp black liquor falling film evaporator and the bamboo pulp black liquor falling film evaporator liquid chamber 8 below. The bamboo pulp black liquor falling film evaporator liquid chamber 8 is a container for storing black liquor in the bamboo pulp black liquor falling film evaporator 1. The upper portion of the bamboo pulp black liquor falling film evaporator liquid chamber 8 is cylindrical and the lower portion is elliptical. The lower portion of the bamboo pulp black liquor falling film evaporator liquid chamber 8 is provided with a variable diameter liquid outlet pipe 7. Differential pressure liquid level gauges are installed on both sides of the bamboo pulp black liquor falling film evaporator liquid chamber 8. The differential pressure liquid level gauge and the variable diameter liquid outlet pipe 7 are both made of corrosion-resistant stainless steel. The two sets of differential pressure liquid level gauges are of the same size, specifications and materials, which can promptly detect the distortion of either liquid level gauge and can continue to ensure the operation of the evaporation system after any differential pressure liquid level gauge is distorted.

[0020] The differential pressure level gauge includes a left differential pressure level gauge 11 and a right differential pressure level gauge 12. The left differential pressure level gauge 11 includes a left gas phase diaphragm 2, a left liquid phase diaphragm 4, a left pressure guiding pipe 15 and a left pressure transmitter 6. The left gas phase diaphragm 2 is installed on the upper left side of the liquid chamber 8 of the black liquor falling film evaporator, and the left liquid phase diaphragm 4 is located on the left side of the lower part of the variable diameter liquid outlet pipe 7. The left gas phase diaphragm 2 and the left liquid phase diaphragm 4 are connected to the left pressure transmitter 6 through the left pressure guiding pipe 15; the right differential pressure level gauge 12 includes a right gas phase diaphragm 3, a right liquid phase diaphragm 5, a right pressure guiding pipe 16 and a right pressure transmitter 9. The right gas phase diaphragm 2 is installed on the upper right side of the liquid chamber 8 of the black liquor falling film evaporator, and the right liquid phase diaphragm 5 is located on the right side of the lower part of the variable diameter liquid outlet pipe 7. The right gas phase diaphragm 3 and the right liquid phase diaphragm 5 are connected to the right pressure transmitter 9 through the right pressure guiding pipe 16. The left gas phase diaphragm 2 of the left differential pressure level gauge 11 and the right gas phase diaphragm of the right differential pressure level gauge 12 are installed at the same horizontal height above the liquid chamber 8 of the bamboo pulp black liquor falling film evaporator, and are located above the liquid level of the black liquor in the bamboo pulp black liquor falling film evaporator liquid chamber 8. The left liquid phase diaphragm 2 of the left differential pressure level gauge 11 and the right liquid phase diaphragm 5 of the right differential pressure level gauge 12 are installed on the left and right sides of the reducing liquid outlet pipe 7 at the lower part of the falling film evaporator liquid chamber, and are located at the same horizontal height. This can solve the problem of the lower liquid phase diaphragm of the existing falling film evaporator differential pressure level gauge being easily distorted by the accumulation of debris or scale in the black liquor on the diaphragm surface.

[0021] The variable diameter liquid outlet pipe 7 includes an upper thick pipe 14, the upper part of the upper thick pipe 14 is connected to the black liquor falling film evaporator liquid chamber 8, and the lower part is connected to the variable diameter pipe 10. The diameter of the variable diameter pipe 10 gradually decreases from top to bottom to two-thirds of the upper part. The lower part of the variable diameter pipe 10 is connected to the lower thin pipe 14. The left liquid phase diaphragm 4 and the right liquid phase diaphragm 5 are respectively installed on the left and right sides of the lower thin pipe 14 and are located at the same horizontal height; it can effectively prevent the liquid level gauge from being distorted due to the instability of black liquor passing through the liquid outlet pipe, thereby ensuring the stable operation of the black liquor evaporation system.

[0022] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications and improvements made by those skilled in the art to the technical solution of the present invention without departing from the spirit and principles of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A liquid level gauge mounting structure on a bamboo pulp black liquor falling film evaporator liquid chamber, comprising a bamboo pulp black liquor falling film evaporator (1) and a bamboo pulp black liquor falling film evaporator liquid chamber (8) below the bamboo pulp black liquor falling film evaporator, characterized in that: A variable diameter liquid outlet pipe (7) is provided at the lower part of the liquid chamber (8) of the bamboo pulp black liquor falling film evaporator, and differential pressure level gauges are installed on both the left and right sides.

2. The liquid level gauge installation structure on the liquid chamber of the bamboo pulp black liquor falling film evaporator according to claim 1 is characterized in that: The differential pressure level gauge comprises a left differential pressure level gauge (11) and a right differential pressure level gauge (12), wherein the left differential pressure level gauge (11) comprises a left gas phase diaphragm (2), a left liquid phase diaphragm (4), a left pressure guide pipe (15) and a left pressure transmitter (6), wherein the left gas phase diaphragm (2) is installed on the upper left side of the liquid chamber (8) of the black liquor falling film evaporator, the left liquid phase diaphragm (4) is located on the left side of the lower part of the variable diameter liquid outlet pipe (7), and the left gas phase diaphragm (2) and the left liquid phase diaphragm (4) are connected to each other through the left pressure guide pipe. (15) is connected to the left pressure transmitter (6); the right differential pressure level gauge (12) includes a right gas phase diaphragm (3), a right liquid phase diaphragm (5), a right pressure guide pipe (16) and a right pressure transmitter (9), the right gas phase diaphragm (3) is installed on the upper right side of the liquid chamber (8) of the black liquor falling film evaporator, the right liquid phase diaphragm (5) is located on the right side of the lower part of the variable diameter liquid outlet pipe (7), and the right gas phase diaphragm (3) and the right liquid phase diaphragm (5) are connected to the right pressure transmitter (9) through the right pressure guide pipe (16).

3. The liquid level gauge installation structure on the liquid chamber of the bamboo pulp black liquor falling film evaporator according to claim 2 is characterized in that: The variable diameter liquid outlet pipe (7) comprises an upper thick pipe (13), the upper portion of the upper thick pipe (13) is connected to the liquid chamber (8) of the black liquor falling film evaporator, and the lower portion is connected to the variable diameter pipe (10), the diameter of the variable diameter pipe (10) gradually decreases from top to bottom to two-thirds of the upper portion, the lower portion of the variable diameter pipe (10) is connected to the lower thin pipe (14), and the left liquid phase membrane (4) and the right liquid phase membrane (5) are respectively installed on the left and right sides of the lower thin pipe (14).

4. The liquid level gauge installation structure on the liquid chamber of the bamboo pulp black liquor falling film evaporator according to claim 2 is characterized in that: The left gas phase membrane (2) and the right gas phase membrane (3) are installed above the liquid level of the black liquor stored in the black liquor falling film evaporator.

5. The liquid level gauge installation structure on the liquid chamber of the bamboo pulp black liquor falling film evaporator according to claim 1 is characterized in that: The upper portion of the liquid chamber (8) of the bamboo pulp black liquor falling film evaporator is cylindrical, and the lower portion is elliptical.

6. The liquid level gauge installation structure on the liquid chamber of the bamboo pulp black liquor falling film evaporator according to claim 1 is characterized in that: The differential pressure level gauge and the variable diameter liquid outlet pipe (7) are both made of corrosion-resistant stainless steel.

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