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Show 5.6.17 7.0 Advantages of Vortex Combustion for Incineration The merits of each type of vortex combustor have been discussed in the preceding pages, the following are their merits over other types of combustors. Vortex combustors have very lengthy residence times which result from either, the impingement of the fuel onto the periphery wall in the slagging type of combustor, or the fact that the fuel follows a different path to that of the air in the non-slagging type. Residence times of 10 times the mean residence time have been observed, even for the non-slagging type of combustor1>12, Very high release rates have been recorded in vortex combustion chambers, in the order of 3xl06 KCal/m3/hr or 1 MW/m3 2,3. This allows significant reductions in the size of such combustion chambers over the equivalent conventional chamber, and also makes it much easier for such an incinerator to be considered for a new waste disposal facility. Vortex combustors have shown their ability to cope efficiently with both simple fuels and those which cause problems in more conventional installations. In general, the slagging type of combustors have been employed where low calorific fuels, such as brown coal have had to be burnt, and the non-slagging type of combustor has been used where high calorific fuels, or those which would produce undesirable chemical reactions if allowed to come in contact with the walls, have had to be burntl/3,13,14, From the preceding discussion it is apparent that the principle of vortex combustion has many favourable aspects from the point of view of incinerator design. The most important of these are, (i) Minimal pollution to the vortex, by keeping the unburnt fuel away from the central flue. (ii) Favourable combustion conditions which enables difficult wastes to be burnt. (iii) High heat release rates, yielding efficient combustion. As a bonus, non-slagging combustors are free from any restrictions on the waste it can burn, due to the chemical interaction which would occur if the |