What Is a Process Furnace?

Industrial furnaces are thermal equipment used in industrial production to heat materials or workpieces by using the heat of fuel combustion or the conversion of electrical energy. Broadly speaking, a boiler is also an industrial furnace, but it is customary not to include it in the scope of an industrial furnace.

Industrial furnaces are divided into two types according to the heating method: one type is

In the foundry, there are

1. Improve fuel combustion.

Fuel is very special as an energy source. First, the total amount of resources is limited, and the total amount of fuel is limited. One day it will dry up. Second, the use of fuel is non-repeatable, and the use of fuel is unidirectional and irreversible. Third, inefficient use of energy. During the use of fuel, certain losses often occur, and the degree of loss varies according to the way of use and the level of control. Fourth, the fuel will have a negative impact on the environment during its use. Fuel is often accompanied by the generation of waste during its use, which causes different degrees of pollution to the environment.

When the fuel is burned in an industrial furnace, it is completed by a burner installed on the industrial furnace, so the performance of the burner is directly related to the fuel consumption of the industrial furnace. Therefore, the performance of the burner should be improved, because only by ensuring that the performance of the burner meets the heating capacity of the industrial furnace and has a low and stable air excess coefficient, can the fuel fully improve the combustion efficiency and make the combustion The device can adapt to higher temperature combustion air.

2. Optimize the furnace lining structure.

Furnace linings of industrial furnaces can be divided into brick furnace linings, infusion furnace linings and fiber furnace linings. At present, most of the domestic heating furnaces use traditional internal fire bricks. The heat dissipation and heat storage of the furnace lining can account for 30% -40% of the total energy consumption. The development trend of furnace building materials is high temperature, high strength and light weight. Reasonable selection of furnace lining materials and optimization of composite furnace lining structure can play a good role in reducing furnace body heat dissipation, reducing heat storage loss and achieving energy saving. First of all, the thermal conductivity of the sintering furnace lining is much smaller than that of the brick furnace lining, and the furnace body has better air tightness, so it can extend the service life and achieve the purpose of energy saving. In recent years, the castables have made great progress in terms of variety and quality. This can meet the requirements of high temperature, rapid cold and heat resistance in the furnace. Using the pouring furnace lining can save about 3% of energy than the brick furnace. Secondly, the internal fire fiber is an ultra-lightweight internal fire material. Its basic performance is low in density and thermal conductivity. The furnace construction of this material can play the role of energy saving and material saving to increase the furnace production capacity. Using refractory fiber linings can save 7% of energy compared to brick furnaces. The development of refractory fiber products, refractory fibers can be used at a high temperature of 1200 degrees, thus promoting the use of refractory fibers.

The construction method of refractory fiber can greatly affect its use effect and service life. Traditional anchoring methods often cause various problems in use. The new construction method can send the high-pressure wind of fiber cotton out of the spray gun, and the binder is mixed with the fiber cotton. This method eliminates the seam of the furnace lining, greatly improves its energy saving effect, and can extend the life of the furnace. The energy-saving effect of infrared energy-saving coating is very high. This coating can be used on various fuel furnaces with a furnace temperature of 1800 degrees. If sprayed on the surface of the furnace lining, a 0.5 mm coating can be formed. The infrared radiation performance of the coating can Play a good effect of increasing thermal efficiency and reducing energy consumption.

3. Improve the level of control.

Methods to improve the level of control: First, control fuel combustion. Computer control of industrial furnaces must achieve a reasonable ratio of furnace temperature, fuel supply, fuel quantity and air quantity. The core of controlling these quantities is to properly proportion the fuel. Control the proportion by measuring the oxygen content in the flue gas. Second, optimize the mathematical model. In order to control the temperature in the furnace, a mathematical model must be reasonably optimized. It is best to use the mathematical model to control the temperature in the furnace to a curve to improve the fuel efficiency in the furnace. ^[1]

Industrial furnaces often involve heating processes such as smelting, drying, baking, and adding chemical reactions during the production process. and

Industrial furnace is a

Each

1.Use energy-saving combustion technology

One of the main reasons for energy waste in industrial furnaces is the loss of thermal energy caused by incomplete combustion. It is caused by chemical incomplete combustion and mechanical incomplete combustion. Chemical incomplete combustion can cause heat loss due to incomplete combustion of carbon monoxide, hydrogen and ammonia combustible gases in the flue gas, which can cause black smoke from industrial furnaces using loose coal as fuel. The high-temperature dust in this black smoke, as well as sulfur dioxide and carbon dioxide, will cause pollution to the atmospheric environment. The heat loss of mechanical incomplete combustion is mainly reflected in the incompletely burned coal particles, ash slag and fly ash particles. These ash and particles can also cause great damage to the environment. Oxygen-enriched combustion technology can greatly increase the combustion temperature and reduce the amount of combustion-supporting air, so as to reduce the amount of flue gas and the loss of gas heat, which not only saves fuel, but also extends the service life of industrial furnaces and furnaces Yields etc. However, oxygen-enriched combustion technology produces a large number of by-products such as nitrogen when separating air, which not only does not improve air pollution, but can worsen the deterioration of air quality. At the same time, related equipment will increase power consumption. Use needs to be improved and researched. In industry, we can also use high-temperature air combustion technology and magnetization treatment before the fuel enters the furnace to achieve energy saving and consumption reduction.

2. Waste heat recovery and utilization technology of industrial furnace

The large amount of flue gas produced by industrial furnaces will take away a lot of heat energy, which is called waste heat. The recovery and utilization of these waste heat can save energy and reduce air pollution. At present we can assemble a preheater and use flue gas to support combustion. It can also be equipped with a waste heat boiler to use the waste heat of the flue gas to boil hot water for industrial or domestic use. We can also use the waste heat of the flue gas to preheat the already cooled components or use it as a heat source for low temperature furnaces. The most widely used and most effective is the use of heat exchangers. When the discharge temperature is below 200 ° C, its energy saving effect can reach more than 30%. At present, the heat exchangers with a wide range of applications in China include chip-mounted, jet-flow, combined, and swirl-tube heat exchangers. After their application, the energy-saving benefits have been greatly improved.

3. Thermal system and detection technology

At present, the energy consumption and pollution of industrial furnaces in China are mainly caused by inadequate or relatively backward technologies for the regulation and detection of fuel and air. This situation places higher requirements on the thermal detection and control technology of industrial furnaces. The use of advanced microcomputer control system and advanced automation control technology can achieve precise control and regulation of the system and its related components, such as controlling the furnace temperature and fuel flow of industrial furnaces, and controlling the oxygen content of flue gas.

4. Improvement of furnace structure and furnace building materials

In order to achieve the purpose of energy saving and emission reduction, we can improve the furnace structure of industrial furnaces or choose new energy-saving materials to improve energy efficiency. Generally speaking, if the furnace space cannot be increased, we can choose to increase the heat exchange area between the furnace and the device, or use a circular furnace body to reduce the area of the outer wall of the industrial furnace and thus reduce the heat loss of the furnace wall. We can also set a fan in the furnace of the industrial furnace to enhance the convective heat transfer function in the industrial furnace. The flow of high-speed airflow in an industrial furnace can damage the surface of the workpiece and hinder heat transfer to shorten the heating time of the workpiece and achieve the purpose of rapidly increasing the temperature of the workpiece. This method will be more effective when applied to a small heating furnace. ^[2]

In the green development of industrial furnaces. The first problem that needs to be solved is the problem of thermal energy conversion and absorption. The more advanced measures are as follows:

(1) Optimize the overall design of industrial furnaces with the core of strengthening heat transfer in the furnace.

(2) Strengthen the pre-heat recovery technology and expand the technical application field. For example: use self-heating burners; regenerative burners, etc. to increase the preheating temperature, or use dual preheating methods.

(3) Use light-weight lining materials to optimize the lining structure. For example, the refractory materials for the furnace roof and side walls are made of fiber modules and new nanomaterials, which not only fully meet the process requirements, but also easy to install. Save construction time for on-site installers.

The current development of industrial furnace technology has undergone tremendous changes. From perceptual design to empirical design, to experience and theory, to current rational design, in fact, each step is on the track of "green road". ^[3]