Design of Blast Furnace Gas Recovery Facilities
1. Introduction
Blast furnace gas (BFG) is an important secondary energy resource produced during the ironmaking process. It not only can provide a cheap and convenient fuel for the production of iron, but also has the potential to replace other existing resources and bring greater economic benefits. Therefore, the recovery of blast furnace gas has attracted significant attention. In general, BFG must be recovered by a suitable facility, with the main purpose of improving energy efficiency, environmental protection, safety and economic benefits. This paper discusses the design of BFG recovery facilities and introduces the main process, types and key points of design.
2. Process Design of BFG Recovery Facility
The process design of the BFG recovery facility is an important part of the design process. The recovery facility commonly consists of five parts, which are gas inlet, gas cleaning, gas treatment, energy recovery and exhaust. Firstly, the gas inlet is responsible for the input of BFG to the system, which usually contains a fan, dust collector and filter box. Next, gas cleaning and gas treatment constitute the main part of the facility. In the gas cleaning part, BFG needs to go through a cyclone dust separator, drop separator and wet desulfurization to reduce their dust and sulfur content. In the gas treatment part, the BFG is further treated with hot air to achieve the desired outlet temperature. After that, the hot BFG enters the energy recovery process, which usually includes a combustion chamber and a set of pipelines, and can be used to produce hot water and steam according to the demands of the production system. Finally, the waste gas is discharged from the exhaust and enters the environment.
3. Types of BFG Recovery Facility
Different types of BFG recovery facilities can be used depending on the specific needs of the plants. The types can be divided into three categories: direct-fired, indirect-fired and combined facilities. The direct-fired facility is the simplest and most cost-effective type, which uses a primary combustion chamber and a secondary combustion chamber. It is suitable for small-scale production and can provide hot water and steam. The indirect-fired facility includes a recovery system, BFG heat exchanger and a direct-fired system. It has the advantages of high efficiency and low cost. Combined facilities are a combination of direct and indirect systems, which are suitable for large-scale production and have higher efficiency.
4. Key Points of Design
When designing a BFG recovery facility, a number of factors need to be taken into consideration. Firstly, for the setup of a BFG recovery facility, dynamic and static simulations of the system should be carried out to determine the optimal parameters. Secondly, the types of equipment should be selected based on the characteristics of BFG and the needs of the plant. Thirdly, the layout of the facility should be carefully designed to ensure safety and energy efficiency. Lastly, the design should also consider heat loss and heat transfer rates as well as local environmental regulations.
5. Conclusion
BFG is an important secondary energy source with great potential for utilization. The design of BFG recovery facilities is a complex task which involves the consideration of various parameters. By following the points discussed in the paper, an effective facility can be set up to improve ironmaking efficiency and create economic benefits.
