I. Purpose and Features
The air electric heater is a new type of heating equipment specially developed by our company for the ash removal system of coal-fired power plants. It is suitable for heating the fluidizing air of the air conveying trough, the fluidizing air of the electrostatic precipitator hopper, and the fluidizing air of the ash storage silo. The equipment consists of two parts: the air electric heater and the control system. The heating element uses 1Cr18Ni9Ti stainless steel seamless tube as the protective sleeve, 0Cr27Ai7Mo2 high-temperature resistance alloy wire, and crystalline magnesium oxide powder, formed by a compression process. The control part adopts advanced digital circuits, integrated circuit triggers, high-voltage thyristors, etc., to form an adjustable temperature measurement and constant temperature system, ensuring the normal operation of the electric heater.
The electric heating tube has good thermal conductivity and excellent insulation. A guide plate is installed inside the heater to achieve uniform heating.
The air electric heater control cabinet and the fluidizing fan have interlocking control functions, local control, and control interfaces. When the equipment suddenly stops and restarts, the control cabinet can automatically adjust smoothly.
II. Technical Parameters
(1) Specifications and parameters of the air electric heater (Table 1)
(2) Main technical indicators of the control cabinet
1. Input voltage: 380V±5% (three-phase four-wire)
2. Rated power: 15KW-90KW
3. Rated current: 23A-136A (single phase)
4. Output voltage: ≤210V (single phase)
5. Temperature control accuracy: 0.5 grade
6. Temperature control range: 0-400 degrees Celsius
III. Main Structure and Working Principle
(1) Structure of the air electric heater (Figure 1)
The air electric heater is composed of multiple tubular electric heating elements, a cylinder, guide plates, and other parts. The tubular electric heating element is made by placing high-temperature resistance wire inside a metal tube and tightly filling the gaps with crystalline magnesium oxide powder that has good insulation and thermal conductivity. Using tubular electric heating elements as the heating body has the characteristics of advanced structure, high thermal efficiency, good mechanical strength, corrosion resistance, and wear resistance. The cylinder is equipped with guide baffles to ensure uniform heating of the air during flow.
(2) Outline drawing of the control cabinet (Figure 2)
(3) Working principle
The SWK-A digital temperature control cabinet uses a digital temperature regulator, integrated circuit trigger, high-power thyristor, and temperature measuring element to form a measurement, adjustment, and control loop. During the electric heating process, the temperature measuring element sends the electrical signal of the outlet temperature of the air electric heater to the digital temperature regulator for amplification. After comparison, the measured temperature value is displayed, and a 0-10V voltage signal is output to the input terminal of the thyristor trigger component to control the output pulse phase, thereby controlling the conduction angle of the thyristor, giving the control cabinet good control accuracy and adjustment characteristics. Using the interlocking device, the air electric heater can be started and stopped remotely.
Item
Model Data
|
Power
KW
|
Input Voltage
V
|
Rated Current
Per Phase A
|
Inlet Temperature
℃
|
Rated Flow
Temperature Rise ℃
|
Inlet/Outlet Flange
Diameter mm
|
Pressure
MP
|
Remarks
|
DYK-15
|
15
|
380/220
|
23
|
-20~50
|
232
|
100
|
P≤0.8
|
|
DYK-20
|
20
|
380/220
|
30
|
-20~50
|
232
|
100
|
P≤0.8
|
|
DYK-25
|
25
|
380/220
|
38
|
-20~50
|
232
|
100
|
P≤0.8
|
|
