Direct-Fired Hot Blast Furnace Project



The CDZR-type hot blast furnace is a heat generation system used in industries such as steel, ceramics, building materials, and others. This machine is fully automatic and features high efficiency, energy savings, and environmental friendliness. It can use various fuel types, including light diesel oil, natural gas, city gas, producer gas, and liquefied gas. The burner output range is 500 to 5000 kW, and the maximum output temperature of the hot air furnace can reach 850°C.

Structural Composition and Description

This product consists of the main body of the hot blast furnace, natural gas burner, gas valve assembly, combustion-supporting centrifugal fan, air supply fan of the supplementary air system, electrical control system, instrumentation, and other components.

1.Main body of the hot blast furnace

The hot blast furnace is constructed with carbon steel. The outer shell is made of Q235 ordinary steel plate with a thickness of 8mm, while the inner shell is made of Q345B manganese plate with a thickness of 10mm. The lining is composed of high-temperature resistant alumina-silicate fiber blanket. The inner combustion chamber is constructed by pouring high-temperature refractory material. The air distribution system utilizes a combination of natural and mechanical air distribution, with natural air distribution being the primary method. The heat lost from the outer shell is blown into the furnace chamber by a fan, serving both energy-saving and temperature adjustment purposes.

2.Natural gas burner

The CD-260W natural gas burner utilizes natural gas as fuel and combines it with auxiliary combustion air to achieve a uniform and stable combustion through multi-jet swirling mixing. The flame is short, which facilitates the formation of a high-temperature combustion zone and enhances the heating capacity. Due to the higher air pressure compared to the gas pressure, the high-velocity air jet can proportionally draw in the natural gas, providing the burner with a certain degree of automatic adjustment capability. The burner is characterized by its small size, light weight, good sealing effect, and easy installation and maintenance.




Working Principal

Combustion System

This system employs an efficient and energy-saving gas burner to ensure sufficient fuel combustion and high thermal efficiency. Additionally, due to its advanced self-control capabilities, it can accurately control the temperature of the hot air, ensuring the stability of the heating equipment. Its advanced self-control features also include automatic purging, ignition, temperature rise, insulation, and the ability to automatically detect and alarm in case of faults, leading to automatic shutdown, thereby ensuring the safe and reliable operation of the system.

The combustion air required enters the combustion chamber with the assistance of the burner's blower.

Principle of Self-control

When the burner receives the start signal from the control system, the burner, under the control of its own program, turns on the blower of the burner to purge and ignite (delay), turns on the fuel solenoid valve, ignites (flame detection), and ignites successfully (delay), open the wind solenoid valve, the damper will automatically open, enter full load operation (enter the temperature control stage), and the burner operation program ends. If the ignition is unsuccessful, the burner will automatically stop, cut off the gas supply circuit, and alarm and self-lock. Before starting the next time, you must press the reset button on the burner program controller to repeat the ignition process. There is a detection point at the outlet of the burner and the heat-using equipment, and the feedback signal is used to control the working state of the burner, which not only saves energy but also meets the heat-using requirements of the heat-using parts.

The hot blast furnace utilizes digital temperature controllers for both the outlet temperature of the hot blast furnace and the temperature of the heating equipment. These controllers are equipped with thermal resistance temperature sensors. The outlet temperature of the hot blast generator is controlled to ensure the burner operates under low load conditions, while the temperature of the heating equipment controls the transition between different burner load levels. If the temperature of the heating equipment exceeds the set limit, the burner will automatically shut down to prevent overheating.

PLC touch screen human-machine interface allows for fully automatic operation, while also providing manual operation functionality. It facilitates centralized control and on-site troubleshooting and adjustments with great convenience.

Centrifugal Fan Control

The start of the burner should be interlocked with the centrifugal fan. It is necessary to start the fan first and then the burner to ensure the safe operation of the hot blast furnace. During shutdown, the burner must be turned off first, and the system will automatically enter the shutdown procedure. After a 30-minute delay, the fan will stop to allow sufficient cooling time for the combustion chamber.




Operating Procedures

Preparation Before Operation:

1.Inspect the installation, support, and thermal expansion allowance of all equipment and pipelines in the hot blastgenerator operating system to ensure that the installation acceptance meets the requirements.

2.Check if the bolts connecting the pipeline system are tightened, if the seals are tight, and if various valves can be opened flexibly and reliably.

3.Inspect whether the electrical control system, instruments, and sensors are installed according to requirements, and whether the cable connections are correct. Check if all alarm systems, control system displays, ignition procedures, and flameout protection systems are functioning properly.

4.Check if the fan drive mechanism has been lubricated, manually rotate the fan spindle to check for any mechanical obstacles, conduct a standalone trial run, and verify if the rotation and noise are normal.

5.Inspect the burner nozzle for blockages and ensure that the air damper is adjustable.

Starting and Stopping Procedures:


To start the operation, follow the steps below once the preparations are complete:

1.Turn on the main power switch. The voltage meter should indicate a power supply voltage of 380V.

2.Turn the key switch to the ON position; the indicator light should illuminate, and the temperature gauge should display.

3.Set the temperature parameters on the temperature control instrument according to the instrument's user manual.

4.Start the circulation fan.

5.Press the ignition button on the burner. After the burner has been pre-blowed, the pilot flame ignites, and the burner operates normally.

To stop the operation:


First, turn off the burner. After a 30-minute delay, the system will automatically shut down the combustion air fan. Finally, cut off the main power supply.




Performance Parameter

Main Technical Parameters

Power Supply Voltage:

380V/220V ± 10%


50Hz ± 5%

Installed Capacity:


Operating Environment:

Temperature ≤ 50°C

Relative Humidity:

R.H ≤ 85%


2.6 million kcal/hour

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Frequently Asked Questions

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Can your reheating furnaces be integrated with our existing production line?

Yes, our experienced engineers can design the reheating furnace according to the customer's existing production line to achieve as high efficiency as it could.

Can you provide references from previous customers?

Yes, we can provide related previous reference.

Can Shanghai Prime Tech provide installation and commissioning services?

We offer installation and commissioning services for our products, which can be provided through on-site dispatch or remote video assistance.

Can Shanghai Prime Tech provide customized solutions?

Yes, we can provide customized solutions to meet your specific needs.


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