CN103406271A - Fiber grade ultra-high molecular weight polyethylene powder air flow classification method - Google Patents

Abstract

The invention relates to a method for airflow classification of fiber-grade ultra-high molecular weight polyethylene powder. The method adopts a multi-stage airflow classification system and matching bag filter, product silo and rotary discharge valve to divide the powder into different stages. Particle size section, to achieve the purpose of shortening the normal distribution width of each particle size section of fiber-grade ultra-high molecular weight polyethylene products, and this method recycles nitrogen, which has a good energy-saving effect.

Description

Airflow classification method for fiber grade ultra-high molecular weight polyethylene powder

technical field

The invention relates to a method for classifying products according to particle size grades of powder materials, in particular to an airflow classification method for fiber-grade ultra-high molecular weight polyethylene powder materials.

Background technique

At present, polyethylene powder classification adopts mechanical vibrating screen classification technology. The principle is to use the excitation force generated by the exciter (eccentric block or eccentric shaft) to make the screen body do periodic reciprocating vibration along the direction of the excitation force. Circumferentially jump on the sieve surface, through different sieve holes, the materials of different specifications are graded to the required sieve surface, so as to achieve the purpose of grading. The vibrating sieve classification technology has problems such as wide particle size distribution of the classified product and small processing capacity.

Contents of the invention

The technical problem to be solved by the present invention is to provide an airflow classification method for fiber-grade ultra-high molecular weight polyethylene powder, which has a large processing capacity and shortens the normal distribution width of each particle size segment of fiber-grade ultra-high molecular weight polyethylene products.

In order to solve the above problems, a method for airflow classification of fiber-grade ultra-high molecular weight polyethylene powder according to the present invention is characterized in that: the method comprises the following steps:

① The ultra-high molecular weight polyethylene powder is conveyed to the fluidized bed room I of the primary classification system (the fluidized bed room I and the air classifier I connected to it are the first class classification system) through the feeding screw, and then cooled by nitrogen gas. The airflow of the device is first classified, the coarse powder is transported by the airflow from the fluidized bed I chamber to the fluidized bed II chamber at the bottom of the fluidized bed I chamber, and the fine powder is conveyed by the airflow to the airflow classifier I for subdivision: a part of the powder The material is taken out of the air classifier Ⅰ by the air flow and then enters the bag filter Ⅰ for separation. The separated solid enters the product silo Ⅰ and is discharged through the rotary unloader Ⅰ; the other part of the powder is intercepted by the air classifier Ⅰ and passed through The rotary unloader II is transported to the fluidized bed II chamber;

②Secondary classification system (fluidized bed II chamber and air classifier II connected to it are two-stage classification system) The powder in the fluidized bed II chamber is first classified by the airflow from the nitrogen cooler, and the coarse powder is fluidized The bottom of the bed II chamber is conveyed by the airflow from the fluidized bed II chamber to the fluidized bed III chamber, and the fine powder is conveyed by the airflow to the airflow classifier II for subdivision: a part of the powder is taken out of the airflow classifier II by the airflow and enters the cloth bag Separation is carried out in the dust collector II, and the separated solid enters the product silo II and is discharged through the rotary unloader III; the other part of the powder is intercepted by the air classifier II, and is transported to the fluidized bed room III through the rotary unloader IV ;

③Three-stage classification system (fluidized bed III chamber and air classifier III connected to it are three-stage classification system) The powder in the fluidized bed III chamber is initially classified by the airflow from the nitrogen cooler, and the coarse powder is fluidized The bottom of the bed III chamber is transported by the airflow from the fluidized bed III chamber to the fluidized bed IV chamber, and the fine powder is conveyed by the airflow to the airflow classifier III for classification: a part of the powder is taken out of the airflow classifier III by the airflow and then enters the bag for dust removal The separated solids enter the product silo III and are discharged through the rotary unloader V; the other part of the powder is intercepted by the air classifier III and transported to the fluidized bed IV chamber through the rotary unloader VI;

④ The powder in the IV chamber of the fluidized bed is discharged through the rotary unloader VII;

⑤ The gas separated from bag filter I, bag filter II, and bag filter III is transported to the nitrogen cooler by the nitrogen circulation fan and then enters the fluidized bed for recycling.

The classification system is 1~N grades, N≥1, and there are N matching bag filter, product silo and rotary unloader connected with the product silo.

The bag filter is replaced by a cyclone separator or a combination of a cyclone separator and a bag filter.

The nitrogen cooler is finned or tube-and-tube.

Compared with the prior art, the present invention has the following advantages:

1. The present invention adopts a multi-stage airflow classification system, which can not only adjust the particle size of the classification by controlling the gas flow rate and the speed of the airflow classifier impeller, but also has a wide range of adjustment, and can shorten the normal state of each particle size section of fiber-grade ultra-high molecular weight polyethylene products. The purpose of distribution width, but also has the advantage of large processing capacity.

2. The present invention recycles nitrogen, which has a good energy-saving effect.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a process flow diagram of the present invention.

In the figure: 1-feeding spiral, 2-fluidized bed, 3-airflow classifier Ⅰ, 4-airflow classifier Ⅱ, 5-airflow classifier Ⅲ, 6-rotary unloader Ⅰ, 7-rotary unloader Ⅱ, 8-rotary unloader Ⅲ, 9-rotary unloader Ⅳ, 10-rotary unloader Ⅴ, 11-rotary unloader Ⅵ, 12-rotary unloader Ⅶ, 13-bag filter Ⅰ, 14 -Bag filter Ⅱ, 15-Bag filter Ⅲ, 16-Product silo Ⅰ, 17-Product silo Ⅱ, 18-Product silo Ⅲ, 19-Nitrogen circulation fan, 20-Nitrogen cooler.

Detailed ways

Example 1

As shown in Figure 1, a kind of fiber grade ultra-high molecular weight polyethylene powder airflow classification method, this method comprises the following steps:

① The ultra-high molecular weight polyethylene powder is transported to the fluidized bed 2I room of the primary classification system (the fluidized bed 2I room and the air classifier Ⅰ3 connected to it are the first class classification system) through the feeding screw 1, and then passed through the nitrogen gas The airflow of the cooler 20 is classified for the first time, the coarse powder is conveyed by the airflow from the fluidized bed 2I chamber to the fluidized bed 2II chamber at the bottom of the fluidized bed 2I chamber, and the fine powder is conveyed by airflow to the air classifier Ⅰ3 for subdivision: Part of the powder is taken out of the air classifier Ⅰ3 by the airflow and enters the bag filter Ⅰ13 for separation. The separated solid enters the product silo Ⅰ16 and is discharged through the rotary unloader Ⅰ6; the other part of the powder is intercepted by the air classifier Ⅰ3 Afterwards, it is transported to room II of the fluidized bed through rotary unloader II7;

②Secondary classification system (fluidized bed 2Ⅱchamber and air classifier Ⅱ4 connected with it are secondary classification system) the powder in the fluidized bed 2Ⅱchamber is initially classified by the airflow from the nitrogen cooler 20, and the coarse powder is in the flow The bottom of the fluidized bed 2 II room is transported by the air flow from the fluidized bed 2 II room to the fluidized bed 2 III room, and the fine powder is transported by the air flow to the air classifier Ⅱ4 for subdivision: a part of the powder is taken out of the air classifier Ⅱ4 by the air flow and enters Separation is carried out in the bag dust collector Ⅱ14, and the separated solid enters the product silo Ⅱ17 and is discharged through the rotary unloader Ⅲ8; the other part of the powder is intercepted by the air classifier Ⅱ4, and is transported to the fluidized bed 2Ⅲ through the rotary unloader Ⅳ9 room;

③Three-level classification system (fluidized bed 2Ⅲ chamber and the air classifier Ⅲ5 connected with it are three-level classification system) the powder in the fluidized bed 2Ⅲ chamber is initially classified by the airflow from the nitrogen cooler 20, and the coarse powder is in the flow The bottom of the fluidized bed 2Ⅲ room is transported by the airflow from the fluidized bed 2Ⅲ room to the fluidized bed 2Ⅳ room, and the fine powder is transported by the air flow to the air classifier Ⅲ5 for classification: a part of the powder is taken out of the air classifier Ⅲ5 by the air flow and enters the cloth bag The dust collector III15 is used for separation, and the separated solid enters the product bin III18 and is discharged through the rotary unloader V10; the other part of the powder is intercepted by the airflow classifier III5, and is transported to the fluidized bed room 2 and IV through the rotary unloader VI11;

④ The powder in the fluidized bed 2Ⅳ chamber is discharged through the rotary unloader VII12;

⑤ The gas separated from bag filter I13, bag filter II14, and bag filter III15 is transported to nitrogen cooler 20 by nitrogen circulation fan 19 and then enters fluidized bed 2 for recycling.

Example 2

As shown in Figure 1, an airflow classification method for fiber-grade ultra-high molecular weight polyethylene powder is different from the method described in Example 1 in that the classification system is 1~N grades, N≥1, and the matching bag dust removal method There are N number of containers, product silos and rotary unloaders connected to the product silos.

Example 3

As shown in Figure 1, a fiber-grade ultra-high molecular weight polyethylene powder airflow classification method is different from the method described in Example 1 in that the bag filter is replaced by a cyclone separator or a combination of a cyclone separator and a bag filter Way.

Example 4

As shown in Figure 1, a method for airflow classification of fiber-grade ultra-high molecular weight polyethylene powder is different from the method described in Example 2 in that the bag filter is replaced by a cyclone separator or a combination of a cyclone separator and a bag filter Way.

The nitrogen coolers 20 described in Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 are of fin type or shell and tube type.

The present invention adjusts the size of the classified particles by controlling the gas flow rate entering each chamber of the fluidized bed 2 and the rotating speed of each air classifier impeller.

Claims (4)

1. fibre-grade ultrahigh molecular weight polyethylene powder air current classifying method, it is characterized in that: the method comprises the following steps:

1. ultrahigh molecular weight polyethylene powder is transported to fluid bed (2) the I chamber of one-level hierarchy system (fluid bed (2) I chamber and coupled air classifier I (3) are the one-level hierarchy system) through feed auger (1), then through the first classification of air-flow from nitrogen cooler (20), the meal material is transported to fluid bed (2) II chamber by air-flow by fluid bed (2) I chamber in bottom, fluid bed (2) I chamber, fine powder material is transported in air classifier I (3) and segments by air-flow: a part of powder is taken out of after air classifier I (3) to enter in sack cleaner I (13) by air-flow and is separated, separating obtained solid enters product feed bin I (16) and draws off by rotary discharger I (6), another part powder is transported to fluid bed (2) II chamber by air classifier I (3) interception by rotary discharger II (7),

2. the powder in secondary hierarchy system (fluid bed (2) II chamber and coupled air classifier II (4) are the secondary hierarchy system) fluid bed (2) II chamber is through the first classification of air-flow from nitrogen cooler (20), the meal material is transported to fluid bed (2) III chamber by air-flow by fluid bed (2) II chamber in bottom, fluid bed (2) II chamber, fine powder material is transported in air classifier II (4) and segments by air-flow: a part of powder is taken out of after air classifier II (4) to enter in sack cleaner II (14) by air-flow and is separated, separating obtained solid enters product feed bin II (17) and draws off by rotary discharger III (8), another part powder, by air classifier II (4) interception, is transported to fluid bed (2) III chamber through rotary discharger IV (9),

3. the powder in three grades of hierarchy systems (fluid bed (2) III chamber and coupled air classifier III (5) are three grades of hierarchy systems) fluid bed (2) III chamber is through the first classification of air-flow from nitrogen cooler (20), the meal material is transported to fluid bed (2) IV chamber by air-flow by fluid bed (2) III chamber in bottom, fluid bed (2) III chamber, fine powder material is transported in air classifier III (5) and carries out classification by air-flow: a part of powder is taken out of after air classifier III (5) and is entered sack cleaner III (15) and separate by air-flow, separating obtained solid enters product feed bin III (18) and draws off by rotary discharger V (10), another part powder, by air classifier III (5) interception, is transported to fluid bed (2) IV chamber through rotary discharger VI (11),

4. the powder in fluid bed (2) IV chamber draws off through rotary discharger VII (12);

5. in sack cleaner I (13), sack cleaner II (14), sack cleaner III (15), separating obtained gas is transported to through nitrogen circulation blower fan (19) that nitrogen cooler (20) is cooling laggardly to be entered fluid bed (2) and recycle.

2. a kind of fibre-grade ultrahigh molecular weight polyethylene powder air current classifying method as claimed in claim 1, it is characterized in that: described hierarchy system is 1 ~ N level, N >=1, and the sack cleaner matched with it, product feed bin and the rotary discharger that is connected with the product feed bin are N.

3. a kind of fibre-grade ultrahigh molecular weight polyethylene powder air current classifying method as claimed in claim 1 or 2, it is characterized in that: described sack cleaner is replaced by the combining form of cyclone separator or cyclone separator and sack cleaner.

4. a kind of fibre-grade ultrahigh molecular weight polyethylene powder air current classifying method as claimed in claim 1 or 2, it is characterized in that: described nitrogen cooler (20) is finned or shell and tube.