A low-steam-consumption thermal abrasive fiber system

Abstract

The invention discloses a low steam consumption hot grinding fiber making system. It includes a digester and a grinding main machine, and also includes two main steam pipelines connected to the digester cylinder of the digester and the grinding chamber of the grinding main machine respectively. A pressure difference pipeline with a pressure difference gauge located between the inlet of the digester cylinder and the inlet of the grinding chamber is connected between the two main steam pipelines. The pressure between the grinding chamber and the digester cylinder is kept balanced or the pressure of the grinding chamber is slightly greater than the pressure of the digester cylinder through the detection of the pressure difference gauge. A compressed air pipeline connected to the main steam pipeline is arranged at the inlet of the grinding chamber of the grinding main machine. Its advantages are: reducing the demand for steam of the system, low operating cost, low investment, and low maintenance cost; the steam generated in the fiber making process is directly recovered through the steam recycling pipeline, which is comprehensively utilized, saving energy, and is applicable to the situation where the original pulping is insufficient in steam supply when increasing production capacity, ensuring normal production and making the most of steam.

Description

Technical Field

[0001] The invention relates to a hot grinding fiber making system, in particular to a low steam consumption hot grinding fiber making system. Background Art

[0002] The hot grinding fiber making system is a continuous separation equipment that separates wood chips and other plant materials into fibers under a certain steam pressure. In order to separate the fibers and reduce power consumption, it is necessary to heat and soften the raw materials in the digester 102 with saturated steam at a certain pressure and temperature before grinding. After softening, the wood chips are fed into the grinding discs on the surface of the moving and static grinding discs in the grinding chamber through the feeder 107 in front of the grinding chamber. The moving disc loaded with the grinding disc rotates at high speed with the main shaft, and the fixed disc loaded with the grinding disc is fastened to the inner side of the grinding chamber shell. The wood chips are compressed, stretched, twisted, and impacted by the teeth of the two grinding discs. The raw materials are ground into fibers or fiber bundles by high-frequency external forces such as impact and friction. The separated fibers are discharged from the grinding chamber together with steam. The fiber discharge process mainly relies on steam. In the prior art, the steam source is divided into two parts. One part is that the water in the raw materials is rapidly vaporized and converted into steam due to the action of mechanical work during the grinding process; the other part is the steam flowing from the digester due to the flow of raw materials and pressure difference. Most of the steam (more than 40%) is discharged with the fibers, resulting in a large consumption of steam and increasing the operating cost of the equipment. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a low steam consumption hot grinding fiber making system which can reduce the steam consumption during hot grinding pulping.

[0004] In order to solve the above technical problems, the low steam consumption thermal fiber grinding system of the present invention includes a cooker for heating and softening raw materials and a grinding host for grinding the softened raw materials. It also includes two main steam pipelines connected to the cooking cylinder of the cooker and the grinding chamber of the grinding host respectively. A pressure differential pipeline with a pressure differential gauge located between the inlet of the cooking cylinder and the inlet of the grinding chamber is connected between the two main steam pipelines. The pressure between the grinding chamber and the cooking cylinder is kept balanced or the pressure in the grinding chamber is slightly greater than the pressure in the cooking cylinder through the detection of the differential pressure gauge. A compressed air pipeline connected to the main steam pipeline and capable of introducing compressed air into the grinding chamber is arranged at the inlet of the grinding chamber of the grinding host.

[0005] A steam recycling pipeline is arranged between the cooking cylinder of the cooking device and the grinding chamber of the grinding main machine.

[0006] The grinding host is provided with a belt screw feeder, and the cooking cylinder of the digester is connected with the belt screw feeder through a stirring and conveying system.

[0007] Valves are provided on the two main steam pipelines, the steam recycling pipeline and the compressed air pipeline.

[0008] Pressure detection devices are provided on the two main steam pipelines and the compressed air pipelines.

[0009] The grinding chamber is provided with a fixed static grinding disc, a dynamic grinding disc that can be rotated by a main shaft, a fixed grinding plate installed on the static grinding disc, and a dynamic grinding plate installed on the dynamic grinding disc. The gap between the fixed grinding plate and the dynamic grinding plate tends to decrease from the inside to the outside until the steam and compressed air can be isolated.

[0010] The fixed grinding plate and the movable grinding plate are sequentially provided with a crushing area, a coarse grinding area and a fine grinding area from the inside to the outside.

[0011] The fixed grinding plate and the movable grinding plate are both provided with a zigzag tooth structure.

[0012] The advantages of the present invention are:

[0013] 1. Compressed air is introduced into the grinding chamber (the compressed air pressure is slightly greater than the pressure inside the grinding chamber), and compressed air is used instead of steam to discharge the ground fibers out of the grinding chamber, which reduces the system's demand for steam, has low operating costs, low investment, and low maintenance costs;

[0014] 2. The compressed air source is clean and pollution-free, and the steam generated during the fiber making process is directly recovered through the steam recycling pipeline, which is comprehensively utilized and saves energy.

[0015] 3. It is applicable to the situation where the steam supply is insufficient when the original pulping capacity is increased to ensure normal production.

[0016] 4. The structure of the grinding disc on the grinding disk has been changed, so that when the raw materials are ground, an area with zero steam velocity is formed outside the grinding area of ​​the grinding disc, which isolates the steam from the compressed air, allowing the steam generated during the grinding process to flow toward the grinding center and enter the digester through the balance pipe on the side of the belt screw feeder to heat the raw materials, thereby maximizing the use of steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a system principle diagram of the low steam consumption thermal grinding fiber making system of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of the grinding chamber in the present invention;

[0019] Figure 3 It is a schematic diagram of the surface structure of the grinding plate in the present invention;

[0020] Figure 4 It is a schematic diagram of the specific volume curve in the present invention. DETAILED DESCRIPTION

[0021] The low steam consumption hot grinding fiber system of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] As shown in the figure, the low steam consumption thermal fiber grinding system of the present invention includes a digester 102 for heating and softening raw materials and a grinding host 105 for grinding the softened raw materials. A cork screw feeder 111 is provided at the front of the digester 102, and a belt screw feeder 107 is provided on the grinding host 105. A stirring and conveying system 108 is provided between the digester cylinder of the digester 102 and the belt screw feeder 107. The digester cylinder of the digester 102 is connected to the belt screw feeder 107 through the stirring and conveying system 108. It also includes two main steam pipelines 101 respectively connected to the digester cylinder of the digester 102 and the grinding chamber of the grinding host 105. As can be seen from the figure, the steam input ends of the two main steam pipelines 101 can be connected to a total main steam pipeline, one of which is connected to the digester cylinder of the digester 102 as a No. 1 conveying pipeline, and the other A main steam pipeline 101 is connected to the grinding chamber of the grinding host 105 as a No. 2 delivery pipeline. A pressure difference pipeline 104 located between the inlet of the cooking cylinder and the inlet of the grinding chamber is connected between the No. 1 delivery pipeline and the No. 2 delivery pipeline. A pressure difference gauge 106 is installed on the pressure difference pipeline 104. Through the detection of the differential pressure gauge, the pressure between the grinding chamber and the cooking cylinder is kept balanced or the pressure in the grinding chamber is slightly greater than the pressure in the cooking cylinder. A compressed air pipeline 103 connected to the No. 2 delivery pipeline and capable of introducing compressed air into the grinding chamber is arranged at the inlet of the grinding chamber of the grinding host 105. A steam recycling pipeline 109 is arranged between the cooking cylinder of the digester 102 and the belt screw feeder 107. Valves are arranged on the No. 1 delivery pipeline, the No. 2 delivery pipeline and the compressed air pipeline 103. Pressure detection devices are arranged on the two main steam pipelines 101 and the compressed air pipeline 103.

[0023] Furthermore, the grinding chamber comprises a fixedly mounted static grinding disc 201, a dynamic grinding disc 202 which can be driven to rotate by the main shaft, a fixed grinding plate 203 mounted on the static grinding disc, and a dynamic grinding plate 204 mounted on the dynamic grinding disc. The fixed grinding plate 203 and the dynamic grinding plate 204 are provided with a crushing area 205, a coarse grinding area 206 and a fine grinding area 207 from the inside to the outside, and the fixed grinding plate 203 and the dynamic grinding plate 204 are provided with a zigzag tooth structure. Figure 4 It can be seen that an arrow indicates the flow direction of steam between the fixed grinding plate 203 and the movable grinding plate 204, the upper arrow indicates the steam passing direction, and the lower arrow indicates the steam returning direction. It can be seen from the corresponding specific volume curve schematic diagram that the up and down directions in the graph represent the radial distance of the grinding plate, the horizontal direction in the graph represents the open area, and the point 301 on the graph is the steam turning point.

[0024] The principle is as follows:

[0025] 1. Add compressed air to the No. 2 delivery pipeline leading to the grinding chamber. When the equipment starts to run, preheat the equipment through the No. 2 delivery pipeline to gradually build up the pressure in the grinding chamber. At the beginning of normal pulping, gradually close the valve of the No. 2 delivery pipeline leading to the grinding chamber, and gradually open the valve of compressed air. Pressure detection is installed on the pipelines for steam and compressed air. The valve opening of compressed air is automatically adjusted according to the pressure of the cooking cylinder to keep the pressure of compressed air always greater than or equal to the pressure of the digester, ensuring that the steam in the digester does not pass through the grinding area of ​​the grinding disc. At the same time, a differential pressure gauge 106 is provided on the pipeline between the digester and the grinding chamber. The pressure between the grinding chamber and the cooking cylinder is kept balanced or the pressure in the grinding chamber is slightly greater than the pressure in the cooking cylinder through the detection of the differential pressure gauge, so that the steam generated during the grinding process does not pass through the grinding area into the grinding chamber under the action of the pressure difference, thereby reducing the amount of steam used.

[0026] 2. Through the design of the grinding disc structure, when the raw materials are ground, an area with zero steam velocity is formed outside the grinding area of ​​the grinding disc, the steam is isolated from the compressed air, and the steam generated during the grinding process flows toward the grinding center and enters the digester through the steam return pipeline 109 on the side of the belt screw feeder to heat the raw materials, thereby maximizing the use of steam.

Claims

1. A low steam consumption thermal fiber grinding system, comprising a digester (102) for heating and softening raw materials and a grinding host (105) for grinding the softened raw materials, characterized in that: The apparatus also includes two main steam pipelines (101) respectively connected to the cooking cylinder of the cooking device (102) and the grinding chamber of the grinding main machine (105); a pressure difference pipeline (104) having a pressure difference gauge (106) located between the inlet of the cooking cylinder and the inlet of the grinding chamber is connected between the two main steam pipelines (101); the pressure between the grinding chamber and the cooking cylinder is kept balanced or the pressure in the grinding chamber is made slightly greater than the pressure in the cooking cylinder by detection of the pressure difference gauge; the grinding chamber of the grinding main machine (105) is A compressed air pipeline (103) connected to the main steam pipeline (101) and capable of introducing compressed air into the grinding chamber is arranged at the inlet; the grinding chamber comprises a fixedly installed static grinding disc (201), a dynamic grinding disc (202) capable of being driven to rotate by a main shaft, a fixed grinding plate (203) installed on the static grinding disc, and a dynamic grinding plate (204) installed on the dynamic grinding disc, wherein the gap between the fixed grinding plate (203) and the dynamic grinding plate (204) decreases from the inside to the outside until the steam and the compressed air can be isolated.

2. The low steam consumption hot fiber milling system according to claim 1, characterized in that: A steam recycling pipeline (109) is provided between the cooking cylinder of the steam cooker (102) and the grinding chamber of the grinding main machine (105).

3. The low steam consumption thermal fiber milling system according to claim 1 or 2, characterized in that: The grinding main machine (105) is provided with a belt-type screw feeder (107), and the cooking cylinder of the cooking vessel (102) is connected to the belt-type screw feeder (107) via a stirring and conveying system (108).

4. The low steam consumption thermal fiber milling system according to claim 3, characterized in that: Valves are provided on both the main steam pipeline (101) and the compressed air pipeline (103).

5. The low steam consumption hot fiber milling system according to claim 1, 2 or 4, characterized in that: Pressure detection devices are provided on both the main steam pipelines (101) and the compressed air pipelines (103).

6. The low steam consumption hot fiber milling system according to claim 5, characterized in that: The fixed grinding plate (203) and the movable grinding plate (204) are provided with a crushing area (205), a coarse grinding area (206) and a fine grinding area (207) in sequence from the inside to the outside.

7. The low steam consumption hot fiber milling system according to claim 6, characterized in that: The fixed grinding plate (203) and the movable grinding plate (204) are both provided with a zigzag tooth structure.

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