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The demands from authorities regarding environmental protection are becoming more and more stringent in practically all countries. This is particularly valid for treatment of industrial or hazardous waste material. Hazardous waste treatment plants are subject to extremely stringent controls regarding the emission of CO2, dioxins, furans, phenols and nitrogen oxides.
The main methods for treatment of hazardous waste are based on combustion. In practice the rotary kiln has proven to be the most suitable and efficient process. In the rotary kiln it is possible to charge and process both liquid, pasty and solid waste at the same time. Also barrels or other containers can be charged directly into the furnace.
These types of plants are normally capable of handling most types of waste, such as solvents, waste oils, paint residues, chlorinated hydrocarbons, resins, phenols, filter cakes, acids, and cyanides. In recent years it has been more complex and expensive to manage the destruction of hazardous wastes. Volumes of this type of material are increasing and the requirement to minimize emissions, particularly with regard to CO is becoming more stringent.
The use of oxygen in the combustion process, whether it is by general enrichment of the combustion air, the use of lanced oxygen in the combustion zone and/or post combustion chamber, or the use of oxy-fuel combustion, is becoming more widespread as the various benefits are realized. General enrichment is an easy way to supply oxygen to the process and is an inexpensive method of boosting productivity. Injection of oxygen via lances makes it possible to direct the oxygen to the combustion zone in the furnace where it is most needed. Both of these methods increase the combustion efficiency but do not deliver the environmental benefits that oxy-fuel burners offer.
The use of oxy-fuel burners is an extremely efficient method of combustion that can be used to burn and destroy liquid waste directly through the burner or to melt away slag build ups in the furnace. The volume of total exhaust gas products are reduced by up to 80% with significant reductions achieved in regards to CO, SOx, and NOx.
The benefits of using oxygen in hazardous waste plants:
- The process temperature can be raised which leads to increased productivity and more complete combustion.
- The production capacity can be increased.
- The reaction intensity is increased.
- The combustion efficiency is improved which means that less fuel is required per ton of waste.
- Flue gas volumes are dramatically reduced when oxy-fuel burners are used, reducing environmental impact with regard to CO emissions.
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