SU763664A1 - Fluidized bed furnace - Google Patents

Description

one

The invention relates to a technique for the heat treatment of various substances in a fluidized bed. The preferred use of the invention is the drying of thermolabile substances, such as magnesium sulfite, ammophos, etc. A distinctive feature of the drying of these substances is their high sensitivity to overheating, violation of temperature conditions JQ and variations in the moisture content of the drying agent. The closest in technical essence is an apparatus for dehydrating saline solutions in a fluidized bed l. The boiling bed apparatus contains a vertical case divided by a gas distributor. The devices are divided into three chambers, equipped with an intermediate chamber located 20 between the lower and upper chambers. In the upper chamber, the product is dried in a fluidized bed; the lower chamber is a firebox. Between the lower and middle chambers there is a set of heat-resistant concrete, designed to reduce the heating of the gas distribution grid due to radiation. Flat gas grille made

from heat resisting steel. The solution to be dried is fed through coarse spray nozzles onto the surface of the layer. Hot flue gases from the bottom chamber pass through the gas distribution grid and enter the fluid bed and exit through the nozzle in the upper chamber. The dried product is discharged from the fluidized bed through a nozzle,

In the known apparatus it is impossible to carry out a two-stage drying process, its gas-distributing device does not protect the processed material from overheating when the latter is in contact with the gas-distributing device. In order to carry out a two-piece process, it would be necessary to use two apparatus, each of them would have its own firebox, which greatly complicates the device, increases its consumption of materials and increases the cost of maintenance. In addition, the known apparatus does not allow to obtain a drying agent differentiated in properties.

The aim of the invention is to intensify the drying process of thermolabile substances, eliminate loss of the product due to sulfatization and thermal dissociation, simplify the design of the apparatus for two-stage drying of thermolabile substances and reduce its material intensity.

The purpose of the invention is achieved by the fact that a fluidized bed furnace comprising a vertical casing divided into chambers, a gas distribution grid, a gas burner, loading and unloading devices is made with an intermediate chamber located between the lower and middle chambers, the latter having a gas burner installed and equipped with a pipe with longitudinal ribs connecting the cavity of the intermediate chamber with the upper chamber and passing axially through the gas-burning device, and on its longitudinal ribs coaxially A heat-resistant pipe is installed, the lower edge of which is located below the level of the openings of the gas-burning device.

The drawing shows a fluidized bed furnace in the section.

The furnace consists of a housing 1, in the lower part of which there is a discharge device 2 for unloading the finished product. Vertically, body 1 is divided into three chambers B, C, D. Chambers B and D dry magnesium sulphite or ammophos in a fluidized bed, and chamber C is a firebox. In chamber D, there is a gas distribution grid 3, made in the form of a multistage truncated cone, in which there are openings 4 for the release of a fluidizing agent, which flows through the duct 5 from the intermediate chamber 6.

A gas burner device 7 is installed in the chamber B, in the side wall of which holes 8 are arranged, which are located in a horizontal plane and are inclined relative to the cylindrical body of the gas burner device 7. A pipe 9 is axially passing through the gas burner device 7, coaxially with which the heat-resistant pipe 10 is installed, resting with its bottom edge on the ledge of the ribs 11, integrally connected to the pipe 9. The upper end of the pipe 9 passes through the concrete slab 12 and ends in the cavity 13, which is formed by a concrete plate and 12 and a metal plate 14. In the metal plate 14, blowing nozzles 15 are fixed, between which chambers 16 are located, to which air is supplied, which is a fluidizing agent in chamber G. At the upper end of the housing 1 there is a fitting 17 for supplying the original product, and on the side surfaces of housing 1 — fitting 18 for leaving the drying gases and fitting 19 for exiting the product from chamber B. The pipes 9 and 10 form annular channels 20 and 21 with the walls of the gas burner device. There are also fittings 22 and 23 for leaving land on the side surface of housing 1 nyh gases from the chamber F and feeding the product from the chamber B to chamber D.

The furnace works as follows.

Gas and air enter the gas-burning device 7 and then through the opening 8 into the annular channel 20, where the gas-air mixture ignites and the flare is twisted around the heat-resistant pipe 10. Due to the ejecting effect of the air-gas 8 jets flowing out of the holes, circulation of the flue gas occurs between the pipes 9 and 10 along the fins 11 to the lower edge of the pipe 10. As a result of this circulation, the flue gases are partially cooled by air moving in the pipe 9 and then mixed with the flame, resulting in a decrease in the temperature of the flame even in the case when the combustion of gas occurs with a slight excess of air (about 1.01-1, 05).

Hot flue gases from chamber B through blow nozzles 15 enter the fluidized bed and exit chamber B through fitting 18. The product to be dried enters the furnace through a charging device — fitting 17, then the partially dried product leaves the fluidized bed through fitting 19 and entering through fitting 23 into chamber D, where it is subjected to final drying and then discharged from the furnace through discharge device 2. Air necessary for fluidizing and drying the product in chamber D enters chambers 16, of which second plate 14 enters the cavity 13, which after passing partially heated and then enters the pipe on 9.Dviga Referring Trug baa 9, the air is heated, whereby the temperature of the flue gases in the chamber B is reduced to 900-1000S without secondary air injection. Heated in the pipe 9 air enters. an additional chamber 6, where it mixes with the flue gases entering this chamber through the annular channel 21. Obtained by mixing heated air and part of the flue gases in chamber 6, the drying agent enters the inside of the multi-stage gas distribution grid 3 and then through the holes 4 enters a boiling layer of the material being dried, after which it leaves the chamber D through a socket 22. The use of the proposed fluidized bed furnace allows two-stage drying of thermolabile substances, such as sulfate Magnesium ammonium phosphate and in a compact housing trekkamernom, wherein two drying chamber to the fluidized bed fluidizing agent are provided from a single furnace. Oven gives

Claims (1)

Claim A fluidized bed furnace for heat treatment of thermolabile substances, mainly for drying magnesium sulfite and ammophos, containing a vertical body divided into chambers, a gas distribution grid, a gas burner, loading and unloading device, characterized in that, in order to intensify the drying process of thermolabile substances, eliminating product losses due to sulfatization and thermal dissociation, simplifying the design and reducing the material consumption of the furnace, it is made with an intermediate chamber placed between the lower and middle chambers, moreover, in the last IQ, a gas burner device is installed, and is equipped with a pipe with longitudinal ribs connecting the cavity of the intermediate chamber with the upper chamber and passing axially through the gas burner device, and on its longitudinal (ribs there is a heat-resistant pipe coaxially installed, the lower edge of which is located below the holes of the gas burner.