CN107889287B

CN107889287B - Electric heater for high-temperature fluidized bed

Info

Publication number: CN107889287B
Application number: CN201710924281.3A
Authority: CN
Inventors: 罗玉英; 吴刚; 薛光磊; 范国伟; 郭琦
Original assignee: CNNC XINNENG NUCLEAR ENGINEERING CO LTD
Current assignee: China Nuclear Seventh Research And Design Institute Co ltd
Priority date: 2017-09-30
Filing date: 2017-09-30
Publication date: 2021-06-22
Anticipated expiration: 2037-09-30
Also published as: CN107889287A

Abstract

The invention provides an electric heater for a high-temperature fluidized bed. The electric heater is wrapped on the outer wall of the fluidized bed cylinder; the outermost surface of the electric heater is an outer layer for heat preservation, and the inner part of the outer layer for heat preservation is a spiral resistance wire and a support body; the support body is designed into an inner layer and an outer layer of perforated structures, the spiral resistance wires are divided into an inner layer and an outer layer to penetrate through the inner layer of perforated holes of the support body and the outer layer of perforated holes of the support body respectively to be bent and wound for connection, the inner layer and the outer layer of spiral resistance wires are switched on simultaneously during initial heating, one path of spiral resistance wires are switched off when the reaction is started, and the single path of spiral resistance wires supplies power for heating so as to meet the heat required by. The invention solves the heating requirements of different stages of fluidized bed production, is convenient for maintenance of the split structure, reduces the surface power of the electric heating element by the winding mode of the spiral resistance wire, prolongs the service life of the heater and meets the heating requirements of the fluidized bed.

Description

Electric heater for high-temperature fluidized bed

Technical Field

The invention belongs to the technical field of uranium purification and conversion, mainly relates to a heating device for activating and maintaining reaction of a high-temperature fluidized bed for uranium purification and conversion, and particularly relates to an external heating device for the high-temperature fluidized bed.

Background

In the domestic uranium purification and conversion production process, the working principle of the high-temperature fluidized bed is as follows: the reaction is first heated to excite the reaction, and some heat is released during the reaction but not enough to sustain the reaction, and some heat needs to be provided to sustain the reaction, but less heat is needed than to excite the reaction.

Therefore, when the high-temperature fluidized bed is used, the reaction needs to be initiated by initial heating, and the reaction is maintained by reducing the heating power after the reaction has started.

Disclosure of Invention

The invention aims to provide an electric heater for a high-temperature fluidized bed, which meets the heating requirements of uranium purification, activation reaction and maintenance reaction of the high-temperature fluidized bed for conversion. The temperature of the high-temperature fluidized bed is more than or equal to 450 ℃.

The technical scheme for realizing the purpose of the invention is as follows: an electric heater for a high-temperature fluidized bed is wrapped on the outer wall of a fluidized bed cylinder body, and materials in the fluidized bed are heated by heating the outer wall of the fluidized bed cylinder body; the outermost surface of the electric heater is an outer layer for heat preservation, and the inner part of the outer layer for heat preservation is a spiral resistance wire and a support body; the support body is designed into an inner layer and an outer layer of perforated structures, the spiral resistance wires are divided into an inner layer and an outer layer to penetrate through the inner layer of perforated holes of the support body and the outer layer of perforated holes of the support body respectively to be bent and wound for connection, the inner layer and the outer layer of spiral resistance wires are switched on simultaneously during initial heating, one path of spiral resistance wires are switched off when the reaction is started, and the single path of spiral resistance wires supplies power for heating so as to meet the heat required by.

The electric heater for the high-temperature fluidized bed is characterized in that the spiral resistance wire is a chromium-nickel resistance wire, and the support body is made of a silicon carbide material.

The electric heater for the high-temperature fluidized bed is characterized in that the insulating plate made of asbestos is arranged between the inner layer of the insulating shell and the spiral resistance wire.

The electric heater for the high-temperature fluidized bed is characterized in that the junction box is arranged outside the outer-layer heat preservation part; the junction box adopts a phenolic aldehyde laminated cloth plate as an insulation main body structure.

According to the electric heater for the high-temperature fluidized bed, the incoming lines and the outgoing lines in the junction box are respectively designed into two paths, namely the two incoming lines of the junction box and the two outgoing lines of the junction box, so that different powers can be switched during initial heating and normal production heating.

The electric heater for the high-temperature fluidized bed is of a split structure and is connected to form a cylinder shape through a plurality of split connecting pieces.

According to the electric heater for the high-temperature fluidized bed, the roller and the handle are arranged on the outer surface of the outer layer heat insulation layer of the electric heater, the split structure is pulled open by the handle during maintenance, and the roller can run along the track arranged on the support around the electric heater.

The electric heater for the high-temperature fluidized bed comprises a metal shell and a heat insulating material, wherein the metal shell is coated outside the heat insulating material; the metal shell is made of carbon steel; the heat insulating material adopts aluminum silicate fiber.

The electric heater for the high-temperature fluidized bed is characterized in that the high-temperature far infrared radiation coating is coated on one surface of the inner layer of the metal shell, which is close to the wall of the fluidized bed.

The invention has the following remarkable effects: the electric heater of the high-temperature fluidized bed solves the heating requirements of different stages of fluidized bed production, is convenient to maintain in an open structure, reduces the surface power of an electric heating element by winding the spiral resistance wire, prolongs the service life of the heater, and meets the heating requirements of the fluidized bed. The electric heater is one of main devices of a uranium purification and conversion system, the device is successfully applied to a plurality of uranium conversion projects, and the running condition is stable and good.

The invention has the following specific beneficial effects:

(1) the metal resistance wire is made of a durable chrome-nickel resistance wire with excellent performance, wound into a spiral line, and penetrated in the through hole of the support body to be connected in a zigzag winding manner. This way, the surface load of the resistance wire can be reduced.

(2) The support body is designed into an inner layer and an outer layer of through holes. When the fluidized bed is in normal operation, the resistance wires on the inner layer and the outer layer are simultaneously switched on, when the reaction starts, one resistance wire is switched off, and the single resistance wire supplies power for heating, so that the heat required by the reaction when the fluidized bed is in normal operation is met.

(3) The junction box adopts a phenolic aldehyde laminated cloth plate as an insulating structural member, and the incoming line and the outgoing line are respectively designed into two paths for switching different powers during initial heating and normal production heating.

(4) In order to be convenient to overhaul, the heater is made into a split structure, the roller and the handle are arranged on the outer surface of the shell, the handle is pulled open during overhaul, and the roller on the heater can run along the track arranged on the support around the heater.

Drawings

FIG. 1 is a schematic structural view of an electric heater for a high temperature fluidized bed according to the present invention;

FIG. 2 is a cross-sectional view of an electric heater for a high temperature fluidized bed according to the present invention;

in the figure: 1. the outer layer is insulated; 2. an insulating plate; 3. a helical resistance wire; 4. a support body; 5. the connecting pieces are split; 6. a junction box; 7. a roller; 8. the inner layer of the heat-insulating shell; 9. laminating a cloth plate by using phenolic aldehyde; 10. a handle; 11. two incoming lines of the junction box; 12. two paths of the junction box appear; 13. perforating the inner layer of the support body; 14. the outer layer of the support body is perforated.

Detailed Description

An electric heater for a high temperature fluidized bed according to the present invention will be further described with reference to the accompanying drawings and specific examples.

As shown in fig. 1 and 2, the electric heater for a high temperature fluidized bed according to the present invention includes an outer layer heat insulation 1, an insulation plate 2, a spiral resistance wire 3, a support 4, a roller 7, a junction box 6, and the like. The electric heater is wrapped on the outer wall of the fluidized bed cylinder and heats the materials in the fluidized bed by heating the outer wall of the fluidized bed cylinder.

The outermost surface of the electric heater is an outer layer heat preservation 1, and a spiral resistance wire 3 and a support body 4 are arranged in the outer layer heat preservation 1; wherein the supporter 4 designs into two-layer perforation structure inside and outside, and the spiral resistance wire 3 is two-layer outside and inside passing supporter inlayer perforation 13 and the outer perforation 14 of supporter respectively and is bent around connecting, and the two-layer spiral resistance wire 3 inside and outside switch-on simultaneously during initial heating, when beginning the reaction, cuts off spiral resistance wire 3 all the way, and the power supply heating of single-way spiral resistance wire 3 to satisfy the heat that the fluidized bed normally worked the needs of reaction.

An insulating plate 2 made of asbestos is arranged between the inner layer 8 of the heat-insulating shell and the spiral resistance wire 3.

A junction box 6 is arranged outside the outer layer heat preservation 1; the junction box 6 adopts a phenolic aldehyde laminated cloth plate 9 as an insulating main body; the incoming line and the outgoing line in the junction box 6 are respectively designed into two paths, namely two incoming lines 11 of the junction box and two outgoing lines 12 of the junction box, so that different powers can be switched during initial heating and normal production heating.

The electric heater of the present invention may be a split structure and connected to form a cylindrical shape by a plurality of split connectors 5. The electric heater is provided with the roller 7 and the handle 10 on the outer surface of the outer layer heat preservation 1, the split structure is pulled open by the handle 10 during maintenance, and the roller 7 can walk along the track arranged on the support around the electric heater.

The spiral resistance wire 3 adopts a chromium-nickel resistance wire with excellent performance and durability, and the support body 4 adopts a silicon carbide material.

The outer layer heat preservation 1 comprises a metal shell and a heat insulation material, wherein the metal shell is coated outside the heat insulation material; the metal shell is made of carbon steel; the heat insulating material adopts aluminum silicate fiber.

The surface of the inner layer of the metal shell, which is close to the wall of the fluidized bed furnace, is coated with high-temperature far infrared radiation paint (such as ZS 1061).

The working principle is as follows: the high-temperature fluidized bed is in a vertical cylindrical shape, when solid materials are in a fluidized state in a barrel body of the fluidized bed, the materials are heated from the outside of the barrel body, when the temperature of the materials reaches about 450 ℃, gas flow from bottom to top fully reacts with the solid materials from top to bottom, and generated solids are led out from an inclined feed opening at the lower part of the barrel body. After the reaction has started, the amount of heat required is about half of the amount of heat required to initiate the reaction.

The heating principle is as follows: the electric heater is wrapped on the outer wall of the fluidized bed cylinder, and materials are heated by heating the outer wall. The power change can be realized under the condition of not stopping the furnace; the time consumed during maintenance is as short as possible; and the service life of the heater is long.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.

Claims

1. An electric heater for a high-temperature fluidized bed is wrapped on the outer wall of a fluidized bed cylinder body, and materials in the fluidized bed are heated by heating the outer wall of the fluidized bed cylinder body; the method is characterized in that: the outermost surface of the electric heater is an outer-layer heat preservation layer (1), and a spiral resistance wire (3) and a support body (4) are arranged in the outer-layer heat preservation layer (1); the support body (4) is designed into a structure with an inner layer of perforation and an outer layer of perforation, the spiral resistance wire (3) is divided into the inner layer and the outer layer of perforation respectively passing through the inner layer of perforation (13) of the support body and the outer layer of perforation (14) of the support body to be bent and wound for connection, the spiral resistance wires (3) of the inner layer and the outer layer are simultaneously switched on during initial heating, when the reaction starts, one path of spiral resistance wire (3) is switched off, and the single path of spiral resistance wire (3) supplies power for heating so as; the spiral resistance wire (3) is a chromium-nickel resistance wire, and the support body (4) is made of a silicon carbide material; the electric heater is of a split structure and is connected into a cylinder shape through a plurality of split connecting pieces (5); the electric heater is characterized in that the roller (7) and the handle (10) are arranged on the outer surface of the outer layer heat insulation layer (1), the split structure is pulled open by the handle (10) during maintenance, and the roller (7) runs along a track arranged on a support around the electric heater; a junction box (6) is arranged outside the outer layer heat preservation (1); the junction box (6) adopts a phenolic aldehyde laminated cloth plate (9) as an insulating main body structure; the inner incoming line and the outgoing line of the junction box (6) are respectively designed into two paths, namely two paths of incoming lines (11) of the junction box and two paths of outgoing lines (12) of the junction box, so that different powers can be switched during initial heating and normal production heating; the outer layer heat preservation (1) comprises a metal shell and a heat insulation material, wherein the metal shell is coated outside the heat insulation material; the metal shell is made of carbon steel; the heat insulating material adopts aluminum silicate fiber; the surface of the inner layer of the metal shell close to the wall of the fluidized bed furnace is coated with high-temperature far infrared radiation coating.

2. An electric heater for a high temperature fluidized bed according to claim 1, characterized in that: an insulating plate (2) made of asbestos is arranged between the inner layer (8) of the heat-insulating shell and the spiral resistance wire (3).