CN100438995C - A method for removing flocs in crushed chestnut shells - Google Patents

Abstract

The present invention relates to the separation technology of floc, specifically a method for removing floc from crushed chestnut shells (in the process of extracting natural brown pigment). For the separation of chestnut shell particles, the crushed chestnut shells are sent to the sorting chamber of the classifier by air from the primary air inlet. Material outlet, wherein, the rotation speed of the rotating turbine of the classifier is 800～1500r/min, the wind speed of the primary air inlet fan is 0.48～0.70m/s, and the wind speed of the secondary air inlet fan is 0.41～0.70m/s. It has the advantages of high separation efficiency and easy operation.

Description

A method for removing flocs in crushed chestnut shells

technical field

The invention relates to the separation of flocs in solid materials, in particular to a method for removing flocs in crushed chestnut shells (in the process of extracting natural brown pigment).

Background technique

The extraction process of natural brown pigment from chestnut shells is as follows: crushing chestnut shells → removing flocs → leaching with alkaline solution → filtering → removing filter residues → concentrating under reduced pressure → settling → filtering and separating → spray drying → finished pigment. In the production and extraction process of the natural brown pigment of chestnut shells, the "floc removal" involved refers to the removal of a kind of hair attached to the inner wall of the chestnut exocarp and the endocarp. When the chestnut shell (nut shell) is not crushed, the hairs are interwoven in the inner wall of the nut shell in a fibrous form and attached to the endocarp. When the chestnut shells are crushed, the fibers are not destroyed but aggregated together to form flocs and scatter, and most of the chestnut shell particles with a certain particle size and low density adhere to the flocs; when the chestnut shells are put into During alkaline extraction, the volume expansion of the flocs is attached to the surface of the extraction solution, which makes the volume of the extraction solution increase, and the chestnut shell particles attached to the surface are still difficult to penetrate. The process has brought considerable difficulty, and if this process link cannot be solved well, it will directly affect the yield of the pigment product and the cost of industrial production. Therefore, understanding and being familiar with the characteristics of the substance and trying to eliminate the floc are the key technical problems to be solved first in the production and extraction process of chestnut shell brown pigment.

Contents of the invention

The purpose of the present invention is to provide a kind of separation (sorting) efficiency high, the method for removing the floc in the crushed chestnut shell that is easy to operate.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A method for removing flocs from crushed chestnut shells. The chestnut shells are crushed, and the frequency conversion turbine airflow classifier is used to separate the flocs from the chestnut shell particles. The crushed chestnut shells are blown by a primary air inlet Sent to the sorting chamber of the classifier, the flocs are removed from the light material outlet, and the chestnut shell particles settle at the heavy material outlet at the bottom of the classifier, wherein, the rotation speed of the rotating turbine of the classifier is 800-1500r/min The wind speed of the fan is 0.48-0.70m/s, and the wind speed of the secondary air inlet fan is 0.41-0.70m/s.

The particle size of described chestnut shell particle pulverization is 3～5mm; The preferred technical parameter scope of above-mentioned winnowing is: the number of revolutions of classifier rotary turbine is 1000～1200r/min, and the wind speed of primary air inlet fan is 0.5～0.65m/min. s, the wind speed of the secondary air inlet fan is 0.44~0.65m/s.

During many times of practice and investigation, the applicant selected the technical process of sorting chestnut shells and flocs by the frequency conversion turbine type sorting system. The high-efficiency frequency conversion airflow classifier with rotating turbine is developed on the basis of centrifugal classifier. This kind of centrifugal classifier is a separation technology between gravity separation and centrifugal separation. When flowing, it can suddenly change the direction, so that the particles can obtain inertial centrifugal force and separate; To control the quality and sorting efficiency of the product, the application of the variable frequency turbine sorting system in the sorting of chestnut shells and flocs is the main technical means for effectively utilizing the characteristics of each particle size for sorting. In the whole technical measure, the grading and sorting system is the key to this technology. Its working principle is: the core of the design of the grading and sorting system lies in the optimization of system parameters and the debugging of operating conditions. Due to the grading process The movement of particles and particle groups is extremely complex, so far there is no accurate and perfect theory to describe it, but the simplified model established when a single particle moves in a centrifugal force field, where the particles are mainly affected by centrifugal force and aerodynamic resistance simultaneously, When the centrifugal force of the particles is greater than the resistance, they will be separated, otherwise the particles with large resistance will be easily carried out by the airflow. A simplified two-dimensional model of single particle motion that has been adopted so far is to use the balance of centrifugal force and resistance to obtain the graded particle size, that is, the cut particle size (dc). The size of the classified particle size dc is mainly inversely proportional to the number of revolutions n of the classifying rotating turbine, and proportional to the air volume Q1/2 of the system operation. In order to meet the classification accuracy requirements, the structure of the system is fixed value k. The functional relationship is as follows: dc=k(Q1/2)n, where: Q-system operating air volume; n-rotating turbine speed; k-structural constant. It can be seen from the formula that the air volume Q and the number of revolutions of the grading turbine n are variable, so that the adjustment of the classification accuracy can be realized not only by adjusting the air volume, but also by adjusting the turbine speed, so that the adjustment range is very wide and fine The adjustable range (45um) is 5-20%, which can meet the separation of different particle sizes. At the same time, the turbine adjustment is frequency conversion digital adjustment, which is intuitive and convenient, and can be carried out in the control room, which saves manpower and electricity. Therefore, this turbine sorting method with rotating impeller has high sorting efficiency and high classification accuracy. , a more advanced sorting technology with stable, reliable and adjustable performance.

Description of drawings

Fig. 1 is a structural schematic diagram of the frequency conversion turbine separator of the present invention. Among them: 1 is the frequency conversion motor, 2 is the transmission shaft, 3 is the primary air inlet, 4 is the impeller, 5 is the sorting chamber, 6 is the light material outlet, 7 is the secondary air outlet, 8 is the heavy material outlet.

Detailed ways

Example 1

The main winnowing technical parameter that the present invention adopts is as follows: classifier rotary turbine speed n: 800～1500r/min; the wind speed of primary air inlet fan is 0.48～0.70m/s, fan air volume Q: 80～100m3/min; The wind speed of the secondary air inlet fan is 0.41~0.70m/s; the classifier power: 1.0~1.5kw/h; the classifier production capacity is 200~1000kg/h.

As shown in Figure 1, the variable frequency motor 1 drives the transmission shaft 2 to control the number of revolutions of the rotating turbine of the classifier to 1000r/min (the rotating speed of the turbine can be adjusted arbitrarily, which can not only improve the sorting efficiency when the amount of floc in the material is large, but also save energy. Electric energy), crushed into chestnut shells with a particle size of 3-5mm, and transported to the sorting chamber 5 by negative pressure through the primary air inlet 3 (air inlet and feed inlet), and the wind speed of the primary air inlet fan is 0.50m/ s, in the sorting chamber, the material is subjected to the joint action of centrifugal force and aerodynamic resistance, but the resultant force behaves differently when applied to particles of different masses, and lighter particle flocs move closer to the turbine or impeller 4 due to aerodynamic resistance > centrifugal force, The turbine guides the light material outlet 6 to be eliminated, and the coarser particles are centrifugal force>aerodynamic resistance, which makes them move outward, decelerate at the periphery, and sink under the action of gravity, that is, the raw material enters the heavy material outlet 8 for storage. The secondary wind is sent into the sorting chamber 5 from the secondary vent 7 on the other side, and its wind speed is 0.6m/s, which can make the floc in the coarse material (i.e. the separated chestnut shell particle raw material) be held up again, Thereby, the sorting efficiency is further improved, and the removal rate of flocs reaches more than 90%.

Claims (3)

1. the method for removing of floccule in the chestnut shell crushed material, it is characterized in that: chestnut shell is pulverized, employing frequency conversion vortex classifier separation realization floccule separates with the chestnut shell particle, specific operation process is, the chestnut shell of pulverizing is sent to the separation chamber (5) of grader with wind by an air intake material mouth (3), floccule exports (6) by light material and is excluded, the chestnut shell particles settling is in the heavy burder outlet (8) of grader bottom, wherein, the revolution of grader revolving wormgear is 800～1500r/min, the wind speed of an air intake blower fan is 0.48～0.70m/s, and the wind speed of secondary air blower fan is 0.41～0.70m/s.

2. according to the method for removing of floccule in the described chestnut shell crushed material of claim 1, it is characterized in that: the granularity that described chestnut shell particle is pulverized is 3～5mm.

3. according to the method for removing of floccule in the described chestnut shell crushed material of claim 1, it is characterized in that: the revolution of grader revolving wormgear is 1000～1200r/min, the wind speed of an air intake blower fan is 0.5～0.65m/s, and the wind speed of secondary air blower fan is 0.44～0.65m/s.

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