Das Projekt "Umruestung eines oelbeheizten Kessels auf Kohlestaub" wird vom Umweltbundesamt gefördert und von Pfleiderer Teisnach GmbH & Co. KG durchgeführt. Objective: To demonstrate the technical feasibility of converting small industrial water tube steam boilers, ranging in steam production from + 10 T/h to 100-150 T/h (that is from the upper limit of shell boilers to the lower limit of power plant boilers) from oil or gas to pulverized coal firing. This is to be achieved by use of a new type of pulverized coal combustor generating a burning flame jet of 100 to 150 M/s flame velocity. General Information: Pulverized coal firing of power plant boilers is a proven technology but no such technology exists for conversion of smaller boilers, since pulverized coal requires two/three times more combustion space than oil or gas. In oil or gas fired boilers combustion space is too small for total pulverized coal combustion. The new technology is intented to solve the problem in a general way, enabling almost any industrial water tube boiler to be converted to pulverized coal. The technology is a new type of pulverized coal combustor generating a jet of 100 to 150 M/s flame velocity and burning 6 to 8 times more pulverized coal than any other design, achieved by increasing turbulant frequency range, which in turn increases mixing efficiency and combustion rate. The result is that + 60 per cent of fuel is burned in the combustors which represent, in volume 5-8 per cent of combustion chamber volume. Hot flue gas is recirculated rapidly in the combustion chamber by the flame jet, generating heat transfer byconvection and flame radiation. This increased heat transfer decreases flue gas temperature at the superheater intake. Four of the pulverized coal combustors were designed and fitted to a 1962 water tube boiler with vertical combustion chamber and two vertical flues producing 40 T/h steam at 75 Bar-520 C, operating at 4,700 h/y with a heavy fuel intake of 13,000 T/y and modified to permit ash removal. Combustor specification is: - fuel - pulverized lignite - capacity 10. 10 Kcal/h (11. 6 MW) each - combustion air 14,000 m3/h 190 C p=Mbar - coal conveying air 330 m3/h, 20 C - turn down ratio 1:20 - flame jet velocity at 100 per cent load - 125 m/s - make - Dr. Schoppe Anlagenbau Additional equipment includes pulverized coal silos of 120 m3 capacity, pulverized coal feeders (fluidized bed rotary pumps), flue gas filter and a 100 m3 ash silo with out loading equipment. Total project cost is DM 5,043 297 including commissioning and test runs. Fuel cost savings of + DM 784,000 represent 2.5 per cent of the annual turnover of the company owning and operating the boiler. Total conversion costs of a standard 40 T/h boiler are estimated at DM 4,650,000. Payback on the project is 3.93 years. Achievements: Boiler modification and installation of the pulverized coal equipment was completed at 28. 09. 84. After two weeks for calibration and control adjustment the boiler arrived at its design specification of 40 T/h steam production at 74 Bar-500 C. After the first weeks of operation the following problems were:::