CN215975565U

CN215975565U - Integrated beta gypsum powder rotary kiln

Info

Publication number: CN215975565U
Application number: CN202121086103.6U
Authority: CN
Inventors: 张慧月; 张美霞; 唐庆渝; 刘鹏; 范卉娟; 刘兴华
Original assignee: Taiyuan Iron and Steel Group Co Ltd
Current assignee: Taiyuan Iron and Steel Group Co Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-03-08
Anticipated expiration: 2031-05-20

Abstract

The utility model relates to the field of beta gypsum powder production. The difference value between the outer diameter and the inner diameter of an annular baffle plate (9) at a kiln tail outlet (7) of the rotary kiln is 5-15% of the diameter of a kiln tail cylinder of the rotary kiln. The utility model has the beneficial effects that: under the prerequisite that improves rotary kiln feed volume and rotational speed, through increasing rotary kiln tail baffle height, the calcination time of extension material in the kiln guarantees that the material is heated evenly, changes in the control running parameter, through the two remove device of U type, desorption steam and part overburning anhydrous gypsum, the building gesso of calcining out, overburning and the underburning gypsum are all less, and steady quality, intensity can reach 4.5~5.0MPa, and the homogeneity is good. The product is used as plastering gypsum, gypsum building blocks, paper plasterboards and the like, the quality problems are reduced, and the feedback effect of subsequent products is good.

Description

Integrated beta gypsum powder rotary kiln

Technical Field

The utility model relates to the field of beta gypsum powder production.

Background

China is a big coal country, electricity is mainly coal electricity, and coal-fired power plants occupy more than 90% of the total generated energy. But the coal-fired power plant discharges a large amount of sulfur dioxide, which seriously pollutes the environment. The limestone-gypsum method becomes the first choice for flue gas desulfurization in most power plants, but the generated desulfurized gypsum causes secondary pollution. At present, almost all of the desulfurized gypsum are applied to building material industries, such as various building materials of alpha-gypsum powder, gypsum products, cement additives and the like, the application technology is mature, and process equipment is specialized. The method is characterized in that desulfurized gypsum is calcined at high temperature to produce building gypsum powder, and the building gypsum powder is applied to the building material industry, which is the first choice of most enterprises.

The desulfurized gypsum calcining technical equipment mainly comprises a vertical frying pan, a rotary kiln, a fluidized bed furnace, a Peter mill and the like. The utility model mainly introduces a calcination technology for improving an integrated inner tube heating type rotary kiln through equipment transformation, and achieves the purpose of preparing high-strength beta gypsum powder.

The calcination process of the integrated inner tube heating type rotary kiln (hereinafter referred to as integrated type) is as follows: the desulfurized gypsum is sent into a double-screw feeder through a weighing belt, the material is quantitatively fed into the rotary kiln, the material and steam in the rotary kiln are subjected to indirect heat exchange through a steam pipeline, free water in the gypsum is removed along with the rise of the material temperature, a semi-crystal water in the gypsum is removed at a higher temperature, the drying and calcining of the desulfurized gypsum are completed in the same equipment, and the semi-hydrated gypsum with stable performance is produced. The process reduces the process flow, reduces the steam consumption and saves the electric energy, but the indirect heating mode has the defects of short material retention time, difficult control of the temperature of the material, difficult stability of the calcination quality, large product performance fluctuation, large heat exhaust loss and the like.

The integral rotary kiln is suitable for places with steam, a plurality of heat exchange tubes are arranged inside the rotary kiln, steam is introduced into the tubes, gypsum is indirectly heated when the barrel is in contact with the heat exchange tubes, and the steam is condensed into water after releasing heat in the tubes. The inner heating pipe type steam rotary kiln adopts the paddle type conveyor for feeding, the material is rotated at a low speed (1-5 r/min) along with the rotary kiln and moves forwards, gypsum is distributed on the lower section of the cylinder body and is in a stacking state, the gypsum cannot be contacted with all heat exchange pipes simultaneously, the heat exchange efficiency is low, and the design of the lifting plate or the material baffle can ensure that the gypsum is uniformly dispersed in the section of the cylinder body and improve the heat exchange efficiency with the heat exchange pipes. The whole kiln body is long in equipment, a steam system is complex, and the manufacturing cost is high.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is as follows: how to provide a simple and feasible method with low cost and good effect for preparing the high-strength beta gypsum powder.

The technical scheme adopted by the utility model is as follows: the difference value between the outer diameter and the inner diameter of an annular baffle plate (9) at a kiln tail outlet (7) of the rotary kiln is 5-15% of the diameter of a kiln tail cylinder of the rotary kiln.

Two devices that remove of U type are connected in kiln tail export (7), two devices that remove of U type include cyclone (2) sack cleaner (4), screw conveyor (5), centrifuge (6), the first import of the solid exit linkage screw conveyor (5) of cyclone (2), and the gas outlet of cyclone (2) passes through the import of pipe connection sack cleaner, and the second import of the solid exit linkage connection screw conveyor (5) of sack cleaner (4), the gas outlet pipe connection centrifuge (6) of sack cleaner (4).

The utility model has the beneficial effects that: under the prerequisite that improves rotary kiln feed volume and rotational speed, through increasing rotary kiln tail baffle height, the calcination time of extension material in the kiln guarantees that the material is heated evenly, changes in the control running parameter, through the two remove device of U type, desorption steam and part overburning anhydrous gypsum, the building gesso of calcining out, overburning and the underburning gypsum are all less, and steady quality, intensity can reach 4.5~5.0MPa, and the homogeneity is good. The product is used as plastering gypsum, gypsum building blocks, paper plasterboards and the like, the quality problems are reduced, and the feedback effect of subsequent products is good.

Drawings

FIG. 1 is a schematic structural view of a U-shaped double removing device according to the present invention;

FIG. 2 is a schematic view of the kiln tail structure of the rotary kiln of the present invention;

FIG. 3 is a schematic view of the construction of an annular single plate of the kiln tail of the present invention;

the device comprises a cyclone separator inlet pipeline 1, a cyclone separator 2, a cyclone separator 3, a cyclone separator outlet pipeline 4, a bag-type dust collector 5, a spiral conveying device 6, a centrifugal machine 7, a kiln tail outlet 8, gypsum powder 9 and an annular baffle.

Detailed Description

The integrated rotary kiln has no pre-drying part in order to save space, and the length of the kiln is 20-40 meters. After the materials enter the rotary kiln, the temperature of the kiln head is reduced, the materials exchange heat with a steam pipeline in the kiln to be dehydrated, a semi-crystal water is removed after the temperature reaches more than 150 ℃, and at the moment, the materials need a large amount of heat sources to keep the dehydration efficiency more than 90%. Calcination of one ton of hemihydrate requires the consumption of approximately 7.0X 105 to 8.0X 105kJ of heat. If the free water content of the desulfurized gypsum is about 15 percent, the kiln length is 20 meters, the feeding amount is reduced by 5 tons/hour, the revolution of the rotary kiln is set to be 1.5-2.0r/min, the discharging temperature at the tail of the kiln still does not reach over 160 ℃, the material is not completely dehydrated, the calcination is not sufficient, and the product performance is unstable.

In order to overcome the defects of the equipment, the utility model adopts the following technical scheme:

(1) the height of a rotary kiln tail baffle plate (an annular baffle plate) is increased to 5-15% of the diameter of the rotary kiln;

(2) the dust removal system adopts a U-shaped double-removal device.

The residence time of the materials in the rotary kiln is inversely proportional to the rotating speed, the material spreading thickness is proportional to the kiln length, if the calcination time of the materials in the rotary kiln is to be prolonged, the calcination time can be realized only by reducing the rotating speed, and the material spreading thickness in the rotary kiln can not be changed at will.

In actual production, the feeding amount may need to be adjusted, once the feeding amount is increased, the discharging amount is accelerated by increasing the rotating speed, the retention time of the materials in the rotary kiln is shortened, the phenomenon of insufficient calcination can occur, the initial and final setting time of the gypsum powder is shortened, the strength is reduced, and the performance is fluctuated, so that the product quality in the later period is influenced. Therefore, a reasonable method for improving the yield and the quality is needed to be found out to improve the calcination degree of the material and improve the product performance.

The main differences between the utility model and the original equipment are as follows: firstly, the height of the kiln tail baffle is increased to 5-15% of the diameter of the rotary kiln, the residence time of the material in the rotary kiln is prolonged to 2-2.5 times, the discharge temperature of the kiln tail reaches 170-.

Secondly, the dust removing equipment adopts a U-shaped double-removal device, the airflow direction at the outlet of the ball mill is changed by 90 degrees, the airflow rotates through a cyclone separator, 70-80% of dust is mechanically separated by utilizing the separation principle, the airflow direction of the residual powder-air mixture is changed by 90 degrees, and the residual powder-air mixture is separated from steam through a bag-type dust remover and returns to the ball mill through a spiral conveying device.

If the free water content of the desulfurized gypsum is about 15 percent, the kiln length is 20 meters, the feeding amount is increased to more than 20 tons/hour from 5 tons/hour by increasing the height of a kiln tail baffle of the rotary kiln and double-removal equipment, the rotating speed of the rotary kiln is increased to 2.0-3.0r/min, the discharging temperature of the kiln tail reaches 150-160 ℃, the materials are fully calcined, and the product performance strength reaches more than 4.5-5.0 MPa.

The feeding amount of the original design is 5 tons/hour, the rotating speed of the original rotary kiln is controlled to be 2.0r/min, the material calcination time is 25min, through detection, the content of the dihydrate gypsum is 3 percent, the content of the hemihydrate gypsum is 84 percent, the setting time of the finished product fluctuates within 5 to 9 minutes, and the strength is more than 3.0. The height of the kiln tail baffle is increased to 10% of the diameter of the kiln, the feeding amount of the rotary kiln is increased to more than 15 tons/hour, the rotating speed is increased to 3.0r/min, and the material calcining time is prolonged to 45 min. As shown in the figure III, the U-shaped double-removal equipment is used, the over-burnt anhydrous gypsum and the under-burnt dihydrate gypsum can be recycled to the ball mill, heat exchange is continuously carried out, the content of the dihydrate gypsum in the final product is 1.0 percent, the content of the hemihydrate gypsum is 90 percent, the initial and final setting time is stabilized at 6-7 minutes, the strength is more than 4.5MPa, and the product quality is greatly improved.

This patent is on original equipment basis, and through increasing kiln tail baffle height extension material calcination time, the material increases in the kiln simultaneously, and steam can assist the wet gypsum of stoving as the heat source, improves steam pressure in the kiln for the gypsum dehydration, two equipment that remove are chooseed for use in the dust removal, can be more effectively with incomplete burning material recovery, realize improving the product totally and increase the quality purpose.

The gesso that kiln tail export came out passes through cyclone import pipeline and gets into cyclone, under the cyclone effect, the gesso that cyclone's solid export came out passes through screw conveyor's first import and gets into the ball mill, cyclone's gas outlet passes through the import of pipe connection sack cleaner, the second import of screw conveyor is connected to the solid exit linkage of sack cleaner, the gesso that comes out from the solid export of sack cleaner gets into the ball mill through screw conveyor's first import, the gas outlet pipe connection centrifuge of sack cleaner.

Claims

1. Integral type beta gesso rotary kiln, its characterized in that: the difference value between the outer diameter and the inner diameter of an annular baffle (9) at a kiln tail outlet (7) of the rotary kiln is 5-15% of the diameter of a kiln tail cylinder of the rotary kiln; two devices that remove of U type are connected in kiln tail export (7), two devices that remove of U type include cyclone (2) sack cleaner (4), screw conveyor (5), centrifuge (6), the first import of the solid exit linkage screw conveyor (5) of cyclone (2), and the gas outlet of cyclone (2) passes through the import of pipe connection sack cleaner, and the second import of the solid exit linkage connection screw conveyor (5) of sack cleaner (4), the gas outlet pipe connection centrifuge (6) of sack cleaner (4).