Manufacturing processes produce exhaust gases and vapors that can harm the environment if not treated.
The core functions of Dürr Air Pollution Control Systems
- Cleaning the exhaust air from manufacturing processes
- Removing exhaust gases from reaction processes
- Complying with official legal directives on emission control,
while at the same time reducing the use of primary energy
- Controlling unpleasant odors
In order to protect the environment, this exhaust gases and vapors must be removed from exhaust air before process air is released into the atmosphere. This type of manufacturing process can be found mainly in the chemical, pharmaceutical, printing, and coating industries, and in paint shops in the automotive sector and other areas of industry.
Air pollution control involves removing solid or gaseous pollutants from exhaust gas and exhaust air. But what is the difference between exhaust gas and exhaust air?
In process terms, exhaust gas is the generic name for gas contaminated with pollutants from a process. This gas might or might not contain oxygen. We use the term exhaust air if the gas in question is ambient air with a normal oxygen content and low pollutant concentrations. Many chemical and combustion processes generate exhaust gas containing little or no oxygen (inert exhaust gas), for example. By contrast, operations such as coating, drying and extraction in the processing industry usually produce exhaust air.
Our air pollution control task remains the same, regardless of the medium. However, the difference between exhaust air and exhaust gas is important when it comes to planning and designing the plant: Whereas exhaust air already contains the oxygen needed to oxidize the pollutants, oxygen-poor exhaust gas might have to be conditioned depending on the process.
Air Pollution Control Systems developed by Dürr that are based on the separation process are used to remove solid particles, such as dust, from waste air. A variety of processes are available for removing gaseous and liquid pollutants from waste air, depending on the chemical and physical properties of the substances. Dürr has an Air Pollution Control solution to meet every customer's individual requirements. Another option is the catalytic process. This also involves combustion of the pollutants, but because of the catalyst the temperatures are much lower than in purely thermal processes.
In addition to the separation process referred to above, there is also the thermal process, which involves the combustion of the pollutants. These are heated to such a high temperature that they are converted into non-hazardous substances. Other alternatives are sorptive processes which either concentrate the pollutants (adsorption) or remove them from the waste air by means of absorption.