First of all, the relevant combustion parameters are measured. After that, starting off with high excess air, the air supply is reduced, until an increase in CO is realised. Now the burner is adjusted to a small amount of excess air, and the following result appears:
Readings X are before adjustment and Reading Y are carried out after adjustment of the system:
|Readings X (before adjustment ):||Reading Y:|
|Oxygen 8 %||Oxygen 3 %|
|ΔT (Tgas - Tamb) 250°C||ΔT (Tgas - Tamb) 190°C|
|Efficiency 85 %||Efficiency 91 %|
|CO 0 ppm||CO 99 ppm|
With assumed annual fuel costs of USD150.000 the savings would be as follows:
91 ( Y ) - 85 ( X ) X 150.000- = USD10.588,-85 ( X )
These fuel costs are by no means extreme examples. Obviously, the price of the flue gas analyser is much less than the annual saving quoted. In general, a return on investment is calculated for three or even five years. Here we have the price of the instrument within one year. Naturally there will be maintenance of the instrument and other factors involved, but the rough calculation clearly shows the potential value of a flue gas analyser in any industry branch where fuel costs are a definite factor.
Not just the cost of the fuel, but its availability should be considered. Fuel of any sort is a major strategic factor and no country wishes to be entirely dependent on outside sources. Since this is a naturally limited resource, care should be taken to use it as sparingly as possible to improve the balance of payments and to ensure an adequate supply in the future. Short-term subsidies of fuel costs to aid industry should be kept as short-term as possible, if they are granted at all. No effort should be spared to reduce the consumption, which will provide a long-term reduction in fuel costs.
Fuel saving is not just a question of reducing the outlay of a company, in many cases it is also a reduction of the dependence of the country on imports. Most fuel is nowadays imported and oil or gas make up a substantial section of the balance of payments, on the wrong side. The dependence on imports has serious political ramifications, as was seen in Europe for the first time during the oil crisis in the 1970s. Reducing the fuel imports would have a very noticeable effect on the balance of payments as well as the political status of most countries.
Fuel taxation varies very widely between countires for the consumer sector, but the greatest users of fuel are to be found in heavy industry or power generation, where taxation is generally much lower to ensure the competitivenesss of the indigenous industry. No country wishes to be fully dependent on outside supply in the major sectors such as iron and steel, power generation, agriculture or general metal-working.
Combustion efficiency is also not the only factor involved in the equation. Ineffective lagging of pipework and burner can lead to immense losses far in excess of any losses due to incomplete combustion or stack loss. These factors are often ignored and this type of maintenance should be carried out assiduously before trying to find extra efficiency in the combustion processes. Fuel savings can be very high in this direction as well.