Design of Dust Purification for Oxygen-Blown Converter
Introduction
Oxygen-blown converters are widely used in the steel industry for the production of high quality steel. The steel industry is subject to rigorous emission standards, and therefore it is essential that the converter is equipped with a dust purification system to reduce emissions of harmful substances discharged from the process. This article describes the design principles and considerations for an efficient, cost-effective dust purification system for oxygen-blown converters.
Design
The design of the dust purification system must focus on the characteristics of the particulates and the concentration of the discharged gases. The particles discharged from the converter are usually in the form of soot, dust and metal oxides, with particle sizes ranging from 0.1 to 10 microns, and concentrations typically ranging from several hundred to several thousand mg/Nm3.
In order to ensure effective dust purification, it is important to ensure that all of the dust particles can be separated from the rest of the discharge gases in an efficient manner. To this end, the dust purification design must include a multi-stage dust collector, consisting of a cyclone separator, followed by a filter separator. The cyclonic separator is an inherently efficient device for separating large particles, whilst the filter separator is better suited for trapping smaller particles.
The filter separator should be selected carefully to ensure maximum efficiency. This can be done by determining the dust load of the process and the expected dust particle size. The filter should be able to trap particles down to 0.1 microns for dust load below 120 mg/Nm^3 and 0.5 microns for dust load above 120 mg/Nm^3. The filter material should also be capable of withstanding high temperatures, as some of the dust particles are generated at temperatures greater than 700°C.
In addition to the dust separation technology, the purification system should also include a chemical adsorption process. Common chemical adsorption processes such as scrubbers, packed tower systems and liquid-film sieve beds can be used to reduce the concentration of harmful substances, such as sulfur dioxide, nitrogen oxides and volatile organic compounds. However, these processes are usually complex and costly, and should therefore only be used in conjunction with efficient dust separation technology.
Finally, the purification system should be designed to be as efficient as possible in its use of energy. The dust separation technology should be designed to minimize the power consumption, and its operation should consider the changing conditions of the process. The filter should also be replaced or cleaned regularly in order to maintain its efficiency. Additionally, a system for re-circulating the exhaust gas should be included in order to recover some of the energy expended in the purification process.
Conclusion
As can be seen, the design of a dust purification system for an oxygen-blown converter requires careful consideration of the properties of the dust particles, the concentration of the discharged gases, and the efficiency of the technology chosen. With careful consideration of these factors, it is possible to design an efficient, cost-effective dust purification system for oxygen-blown converters.
