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Show 3 1.2 Mechanical atomization Mechanical atomization is widely used in the fuel oil burners used for glass melting and other high temperature heating applications. It is attractive to furnace operators due to the single fluid requirement for atomization, simplified piping and simple atomizer construction. Here, the fuel oil is pressurized using a high pressure fuel p u m p and it is transported to the atomizer through a welded (and thick wall piping) to avoid leakage. The fuel oil at high pressure (5 to 10 bar) is expanded in a special spray tip having a relatively small orifice. The liquid fuel is atomized in a fine spray or mist due to the high velocity expansion from a small orifice. Both frictional and inertial forces are responsible for the overall spray formation. The atomized spray is subsequently allowed to mix with the oxidizer (air or oxygen) in a burner. The commercial spray tips offer a wide selection of spray patterns (for various flame shapes), capacities (for firing ranges) and materials. Capacities range from 0.01 to 100 liters/minute of fuel oil are available. The disadvantage with the above spray tips are a low turn-down ratio, a relatively short life span (due to tip erosion) and frequent cleaning requirements due to the small orifice. 2. INDUSTRIAL EXPECTATIONS AND ATOMIZER DESIGN According to applications specificity, such as glass melting, steel reheating/melting, chemical process heating, waste incineration, etc., Air Liquide can select the right atomizer design and provide the required flame characteristics to meet the furnace or heating load requirements. As an illustration, Fig. 2 shows how Air Liquide engineering adapts its technology to industrial expectations through an application-technology diagram. The objective is to match the atomizer characteriztics with the process expectations. Air atomization j*"-1 DUAL o O Air Liquide atomizers Driving force Low pressure 02 atomizer Figure 2 : H o w R & D reacts to changing industrial expectations (on the left of the graph, the atomizing fluid is air; on the right of the graph, it is oxygen) The key factors represented in Fig. 2 (air vs 0 2 atomization, flat flame, etc.) are adressed below |