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Show 99.99% ORE in 1/4 to 1/3 time typical in long flame combustion systems.(2) These combustors do not require a large chamber to insure that combustion of the fossil fuel is complete as is typical in many boilers and process heaters. As a result, the length of chamber needed to insure completion of combustion is not much larger than the combustion chamber of the burner. See Fig. 1, 2. Compare the chamber size needed for the laminar flame to that for the high intensity flame. Heat losses are greater due to the increased shell losses. Refractory weight is also much greater by a factor 2+. Sufficient test data has ~n obtained to show that many high intensity combustion systems can achieve 99.99% ORE at 0.75 to 1.0 sec. vs 2.0 to 3.0 sec. for the laminar flame (low turbulence) with lower average temperatures of the flame envelope. High intensity combustors will achieve much higher adiabatic flame temperatures permitting 99.99% ORE in a fraction of the time. LIQUID DATA In order to achieve these levels of complete combustion, especially with the variety of wastes that are generated in industry, proper design of the liquid transport and atomization system was required. In Figure 3, note the variations in heating value that is typical in wastes generated from processes containing chlorine. As the chlorine content increases, heating value decreases. In Figure 4, note the temperatures that are generated by these wastes at varying excess air levels. High intensity burners will operate at excess air levels of 5 - 10% while a laminar flame burner (low turbulence) usually requires excess air rates in the range of 30 to 50% excess. Stability of combustion deteriorates rapidly below 1316°C. (2400°F.). Therefore, note that there is a limitation on the waste heating value that can be handled by the type of burner . . High intensity burners operating at 5% excess wlll burn waste fuels with HV as low as 2500 Kcal/kg (4500 Btu/lb). A laminar flame burner requires a minimum of 3333 Kcal/kg (6000 Btu/lb). Therefore, a waste having a HV of ~5~0 Kcal/kg (4500 Btu/lb) would require auxlllary fuel when burned in a laminar type flame burner. 336 The data in Table I indicates additional important information necessary in the proper design of a combustion system for waste fuels. TABLE I Waste Liquid Fuels Data Needed For Incinerator Design Chemical Composition Density Heat of Combustion Viscosity Corrosivity Chemical Reactions Polymerization Solids Content Ash Reaction-Refractories Slag Formation Combustion Gas Analysis Nitrogen Composition HIGH VISCOSITY LIQUIDS - Two of the most critical problems which have been overcome in the design of waste fuel burning systems are those for the highly viscous waste and those for wastes containing a high ash component. Incinerators have been designed and are operating with both types of wastes. It would not be practical to attempt to burn a high ash waste in a heat recovery device. However, high viscosity fuels can and should be considered for waste heat recovery applications. Fig. 5 shows a typical viscosity curve for fuel oils and also shows a waste with a viscosity of 4500 ssu at 149°C. (300°F.). Note the zones for recommended pumping viscosity and also recommended atomizing viscosity. For No.6 fuel oil, 49°C. to 65°C. (120°F. to 150°F.) is recommended for pumping. For a good atomizer, No.6 oil temperatures should be in the range of 88°C. to 111°C. (190°F. to 230°F.). In the case of the high viscosity waste material, temperatures of 149°C. to 175°C. (300°F. to 350°F.) were required to pump the material. However, at 232°C. (450°F.), polymerization of the liquid takes place. This prevented the proper temperature level needed for good atomization. (3) |