In-Line Cleaning System
Niels Rozendaal explains a low fouling boiler concept with an APCS in-line cleaning technology and the applications it can be used in. Optimum developed i Is low fouling boiler concept with patented Automatic Pipe Cleaning System (APCS) in-line cleaning technology as a waste heat recovery solution for fouling applications. It was by coincidence that it came in contact with applications in the glass industry where it found fouling in waste heat boilers was a serious issue. The company has realised more than 40 waste heal recovery systems in fouling applications with most in the glass industry. It has applied its technology in combination with different furnace types and albo works with major container and flat glass producers.
The fouling mechanism on the exchanger surface of a boat exchanger in the flue gas stream of a glass furnace is dictated mainly by sublimation.
A portion of the sodium and sulphate goes through a phase change from gas to solid under the influence of the lower temperature on the heal exchanger surface. During this phase change the solids formed arc sticky and sublimate and condense on the heat exchange! sulfate. Within specific temperature ranges some of the fouling is present as a paste, \s soon as the fouling is solid and removed from the heat exchanger surface it is no longer sticky.
Hie company designs its boilers to be less sensitive for fouling and, in combination with its automated pipe cleaning system, it can control the fouling. The fouling removed leaves the boiler with the flue gas.
Its oldest reference in the glass industry is the installation at AGC Mai glass in Tiel, The Netherlands on a 500 tonne/day gas and oil-fired float line.
It installed the boiler with APCS in January 2007, replacing a water tube boiler that suffered from erosion and corrosion issues and needed frequent slops lor manual cleaning.
Optimum said the system has never been stopped for cleaning. After more than five years of operation there is no sign of corrosion or erosion, and no overhauls or repairs on the boiler. The APCS has been overhauled after four and a hall years of operation.
An Important characteristic is that the boiler is constantly and effectively cleaned resulting in a constant and low-pressure drop.
This leads to stable furnace operation. The company found that, in some applications, due to the reduction of the flue gas volume as a result of cooling the flue gas, the effective pressure drop in the flue gas path of the furnace did not increase and no additional fan capacity was required to overcome Lhe pressure drop in the boiler.
If the technology is compared with water tube boilers, soot blowers and/or hall rain installalions, the cleaning technology can serve close to 100% of the surface area, meaning significantly less i >r no stops for cleaning. The systems do not erode and are cheaper than the more complex water tube configuration.