Pusher type reheating furnaces are an essential component in the steelmaking process. These furnaces are used to heat steel billets, slabs, blooms, and beam blanks from ambient temperature to their rolling temperature, typically around 1150°C. The reheating process is crucial for preparing the steel for the subsequent rolling process. Pusher-type reheating furnaces are highly efficient, cost-effective, and can handle large volumes of steel stock.

Pusher type reheating furnaces come in different types, including coal-fired, oil-fired, and gas-fired continuous heating furnaces. They are classified depending on the fuel, temperature system, and furnace type. The pusher type furnace is a continuous heating furnace that uses a mechanical system to push the steel stock through the furnace. The furnace is designed to ensure the steel stock is always well-aligned and the heating chamber has near-total lack of cooled elements, making it highly energy efficient.

Pusher type reheating furnaces have several advantages and applications in the steel industry. They can handle large volumes of steel stock, have low operating costs, and require low CAPEX. They are also highly automated, making them easy to operate and monitor. In this article, we will explore the fundamentals of reheating furnaces, pusher type furnace overview, process and workflow, control systems, advantages and applications, maintenance and safety, innovations and developments, market trends, and future outlook.

Key Takeaways

• Pusher type reheating furnaces are used to heat steel billets, slabs, blooms, and beam blanks from ambient temperature to their rolling temperature, typically around 1150°C.
• They are highly efficient, cost-effective, and can handle large volumes of steel stock.
• Pusher type reheating furnaces have several advantages and applications in the steel industry, including low operating costs, low CAPEX, and highly automated.

Fundamentals of Reheating Furnaces

If you are looking to learn about pusher type reheating furnaces, it’s essential to understand the fundamentals of reheating furnaces in general. In this section, we will cover the design principles, heat transfer mechanisms, and fuel types and combustion used in reheating furnaces.

Design Principles

Reheating furnaces are designed to heat up metal billets, slabs, blooms, or other semi-finished products to the desired temperature before they undergo further processing, such as rolling or forging. The size of the reheating furnace is usually expressed as the capacity to supply hot steel stock to the rolling mill from the cold stock and is expressed in tons per hour. The energy efficiency of reheating furnace is usually defined as an increase in the steel stock heat content when heated from the cold stock.

There are four types of reheating furnaces: pusher-type heating furnace, walking beam furnace, rotary bottom furnace, and compartment furnace. However, the pusher type furnace is the most commonly used type for continuous heating of metal billets before rolling.

Heat Transfer Mechanisms

Heat transfer mechanisms used in reheating furnaces include conduction, convection, and radiation. Conduction is the transfer of heat through a material, while convection is the transfer of heat through a fluid. Radiation is the transfer of heat through electromagnetic waves.

In reheating furnaces, heat transfer occurs through the combustion of fuel in the furnace’s burners. The hot gases produced by the combustion process transfer heat to the metal stock through convection and radiation. The metal stock’s heat content is then increased, and it becomes ready for further processing.

Fuel Types and Combustion

The fuel used in reheating furnaces includes natural gas, coke oven gas, blast furnace gas, and fuel oil. The type of fuel used depends on the availability and cost in the local market. The combustion process in the furnace’s burners is controlled to ensure efficient use of fuel and to minimize emissions.

In conclusion, understanding the fundamentals of reheating furnaces is essential to gain a better understanding of pusher type reheating furnaces. The design principles, heat transfer mechanisms, and fuel types and combustion used in reheating furnaces play a crucial role in the efficient and cost-effective heating of metal stock.

Pusher Type Furnace Overview

If you work in the steel industry, you’re probably familiar with pusher type reheating furnaces. These furnaces are used to heat metal billets before rolling, forging, or heat treatment. In this section, we’ll give you an overview of pusher type furnaces, including their operational characteristics and components.

Operational Characteristics

Pusher type furnaces are continuous heating furnaces, meaning they keep a steady flow of material moving through the furnace. They are designed to heat metal billets to a specific temperature before they are processed further. The temperature of the furnace is carefully controlled to ensure that the billets are heated evenly and to the correct temperature.

One of the key advantages of pusher type furnaces is their ability to handle a wide range of billet sizes and shapes. They can be used to heat everything from small round billets to large rectangular slabs. This flexibility makes them a popular choice in many different types of steel production facilities.

Components and Structure

Pusher type furnaces consist of several key components, including the furnace shell, pusher mechanism, and combustion system. The furnace shell is made of refractory materials that can withstand the high temperatures inside the furnace. The pusher mechanism is responsible for moving the billets through the furnace, typically using a series of pusher rams.

The combustion system is responsible for heating the furnace. Depending on the design of the furnace, it may use natural gas, oil, or coal as a fuel source. The combustion system is carefully designed to ensure that the fuel is burned efficiently and that the temperature inside the furnace remains constant.

In addition to these key components, pusher type furnaces may also include a variety of sensors and control systems. These systems are used to monitor the temperature inside the furnace, adjust the fuel flow rate, and control the movement of the pusher rams.

Overall, pusher type furnaces are an essential component of many steel production facilities. Their ability to handle a wide range of billet sizes and shapes, combined with their precise temperature control, makes them a popular choice for many different types of steel processing.

Process and Workflow

If you work in the steel industry, you’re probably familiar with pusher type reheating furnaces. These furnaces are used to heat steel billets, slabs, and blooms to the required temperature before rolling. The heating process is essential for the quality of the final product, and it needs to be precise and efficient.

Material Handling

The first step in the process is the material handling. The steel billets are transported from the storage area to the furnace using a conveyor system. The conveyor system needs to be designed to handle the weight and size of the steel billets. Once the billets are in the furnace, they are pushed through the furnace by a pusher mechanism. The pusher mechanism needs to be carefully designed to ensure that the billets are pushed through the furnace at the correct speed and with the correct amount of force.

Heating Cycle

The heating cycle is the most critical part of the process. It is during this phase that the steel billets are heated to the required temperature. The heating cycle needs to be carefully controlled to ensure that the billets are heated evenly and to the correct temperature. The heating cycle is typically divided into three stages: preheating, soaking, and heating.

During the preheating stage, the steel billets are heated slowly to remove any moisture that may be present. This stage is critical to prevent any explosions or damage to the billets. Once the preheating stage is complete, the billets move on to the soaking stage. During the soaking stage, the billets are held at a constant temperature to ensure that they are heated evenly. The soaking stage is critical to ensure that the billets are heated to the correct temperature and that they are ready for the final heating stage.

The final heating stage is where the billets are heated to the required temperature. This stage needs to be carefully controlled to ensure that the billets are heated evenly and to the correct temperature. Once the final heating stage is complete, the billets are pushed out of the furnace and onto the rolling mill.

In conclusion, the process and workflow of a pusher type reheating furnace are critical to the quality of the final product. The material handling and heating cycle need to be carefully designed and controlled to ensure that the billets are heated evenly and to the correct temperature.

Control Systems

Pusher type reheating furnaces are complex systems that require precise control to ensure optimal performance and energy efficiency. Control systems are used to regulate the temperature of the furnace and automate the entire process.

Temperature Regulation

Temperature regulation is essential for the proper functioning of the furnace. The temperature must be maintained at a constant level to ensure that the billets are heated evenly. This is achieved through the use of advanced process control systems based on a two-layer linear model predictive control strategy [1]. The system uses a virtual sensor to estimate the temperature of the billets inside the furnace and adjust the temperature accordingly.

The control system also uses a first-principles nonlinear model to obtain accurate estimations of the billets’ temperature inside the furnace [2]. This model is used to optimize the temperature control system and ensure that the temperature is maintained at a constant level.

Process Automation

Process automation is another critical aspect of pusher type reheating furnaces. Automation systems are used to control the entire process, from loading the billets into the furnace to unloading them once they are heated.

The automation system uses sensors to detect the presence of billets and adjust the speed of the pusher accordingly. This ensures that the billets are pushed through the furnace at a constant speed, which is essential for maintaining a constant temperature.

The automation system also controls the combustion process, ensuring that the fuel is burned efficiently and that the furnace operates at optimal energy efficiency. This reduces energy consumption and minimizes the environmental impact of the furnace.

In conclusion, control systems are essential for the proper functioning of pusher type reheating furnaces. Temperature regulation and process automation are critical aspects of these systems, which ensure optimal performance and energy efficiency.

[1] Model Predictive Control of a Pusher Type Reheating Furnace

[2] Modelling and experimental model validation for a pusher-type reheating furnace

Advantages and Applications

Energy Efficiency

Pusher type reheating furnaces are known for their high energy efficiency. They are designed to heat steel billets quickly and uniformly, reducing the amount of energy required and minimizing heat loss. The use of advanced technologies, such as oxygen-enhanced combustion, can further improve energy efficiency and reduce greenhouse gas emissions.

Industrial Uses

Pusher type reheating furnaces are widely used in the steel industry for heating steel billets prior to rolling. They are ideal for heating round billets and steel slabs quickly and uniformly, making them suitable for use in a variety of industrial applications. Pusher type furnaces are commonly used in the production of wire rods, bars, and sections.

In addition to their use in the steel industry, pusher type reheating furnaces can also be used in other industrial applications. For example, they can be used in the production of aluminum, copper, and other metals. They are also used in the production of glass, ceramics, and other materials that require high-temperature heating.

Overall, pusher type reheating furnaces offer a number of advantages over other types of heating equipment. They are energy-efficient, fast, and reliable, making them ideal for use in a wide range of industrial applications.