Combustall Technical Report
Combustall is a petroleum based fuel improvement additive. The chemical agents in Combustall not only improve combustion but also solve several of the problems associated with using fuel oil. The following is a discussion about how Combustall improves combustion, excess oxygen, vanadium deposits, SO3, NOx, fuel savings and sludge deposits.
Every boiler suffers from less than total combustion.
Combustall Solution: The Combustall formula includes a catalyst that promotes complete combustion, improving efficiency. More complete combustion results in less particulate emissions and reduces opacity (up to 25%). More complete combustion also reduces excess air, thus lowering excess oxygen to it's ideal condition.
During combustion, if Sodium and Vanadium are present in the fuel, then sodium vanadates are formed which can have melting points in the 480-700 °C range. At this temperature the deposits are in a molten and very highly corrosive form. In this phase, the vanadates attack the metal surface within the boiler, causing high temperature corrosion. The molten deposits also serve as the primary mechanism for conversion of SO2 to SO3.
Combustall Solution: The Combustall formulation increases the melting point of the Vanadium to 1040-1120 °C reducing it to a soft powder that is easily removed by the hot gases or the soot blowers.
Impurities in fuel, as well as the by-products of incomplete combustion can form deposits on the burners, water walls, superheater, generating banks, economizer and air heaters. These deposits reduce the heat transfer efficiency of the boiler.
Combustall Solution: Combustall will reduce deposit formations on the burner improving spray patterns, atomization and combustion efficiency. Combustall will also increase the melting point of the deposits causing them to be less adhesive and easily blown off by the hot gases and soot blowers. This will significantly increase the transfer of heat through exposed surfaces and improve boiler efficiency. Combustall has extended cleaning intervals by 200% and 300%.
During typical boiler combustion sulfur in the fuel is converted to SO2 and SO3. As hot SO2 gases flow past the Vanadium Pentoxide deposits, SO2 is converted to more SO3. High concentrations of SO3 in the back end raise the dew point of the flue gas causing the SO3 to convert to H2 SO4 (sulfuric acid). Because H2SO4 is extremely corrosive severe low temperature corrosion can form in the economizer, the air heater and the back-end of the boiler.
Combustall Solution: As mentioned above, Combustall's formulation virtually removes all molten Vanadium deposits from the boiler, eliminating the primary mechanism for conversion of SO2 to SO3. As a result, the concentration of SO3 is lowered significantly in the back-end, causing a drop in the dew point. A lower due point means the minimum stack temperature required to prevent H2O condensation is decreased. In addition, Combustall's combustion catalyst will lower the excess air, which means less oxygen is available to form SO3. Using Combustall has reduced SO3 levels by 50%. This SO3 reduction means consumers can use 3% sulfur fuel oil and achieve SO3 concentrations of 1% sulfur fuel oil (untreated).
During combustion, oxygen and nitrogen form to produce oxides of nitrogen NOx. This is a very undesirable condition for the flue gas.
Combustall Solution: The combustion catalyst causes a more complete combustion of the fuel, allowing for a reduction of excess air. Excess air reduction decreases both the nitrogen and the oxygen available to form NOx. Reductions of up to 10% have been achieved.
The largest operational expense for a boiler is fuel. It is ideal to reduce the amount of fuel a boiler uses for a given output.
Combustall Solution: The combination of improved combustion efficiency, decreased excess oxygen and improved heat transfer has produced reduced fuel costs by 4% to 17%.
Fuel oil will often form sludge, gum and other deposits. These deposits can clog fuel lines, strainers and burners.
Combustall Solution: When mixed with fuel oil Combustall breaks down sludge forming compounds. Once broken into fine particles these compounds are kept in suspension. In suspension the particles can pass through the pumping and combustion system without clogging.
UsageCombustall is used in two stages. During stage 1 high concentrations (1:2000 to 1:3000) of Combustall are used to completely clean the dirty boiler. During stage 2, the "keep clean" mode, a reduced concentration (1:3000 to 1:6000) of Combustall is used to keep the boiler clean and operating at peak level.
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