Cel 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.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 encountered :- fuel irregularities - oversized particles up to 8 mm and inorganic matter were found in the pulverized coal, causing problems and erosion of feeding machines and burners.- ash deposits - ash deposits inside the combustor and boiler combustion chamber sometimes sintered and built slag deposits. This will be overcome when more pulverized coal with less oversized particles above 1 mm is used.- hot gas circulation - it was found to be unnecessary, due to rapid gas recirculation inside the boiler combustion chamber, to operate the hot gas circulation system, which is to be removed.- bag filter drag - pressure drop of flue gas passing the bag filter increased duringthe first three weeks because average fly ash particle size, being smaller than anticipated, formed a stable ash cake on the filter bag.further adaptations became necessary to auxiliary equipment such as ash conveyors and electric controls.During tests, the boiler load was 35-36 T/h (88-90 % capacity). The O2 flue gas content was 2. 0-2. 5 % and unburned coal 0.16 % resulting in by SO2 and NOx have been reduced to 25-30 % in comparison with heavy oil.Flue gas analysis results, corrected to 6 % O2 and NOx calculated as NO2, under standard conditions :- CO = 52 mg/m3- SO2 = 673 mg/m3- NO2 = 440 mg/m3All figures met requirements of the German Clean Air Acts.Further developments to make improvements will be made in the following :- ash transportation- bag filter draf- slag depositsA survey of the German boiler market indicates that +- 70 % of the 300 industrial water tube boilers currently installed can be converted. The same survey suggested 800 boilers are installed in the EEC.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 % of fuel is burned in the combustors which represent, in volume 5-8 % 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 % load - 125 m/s- make - Dr. Schoppe AnlagenbauAdditional equipment includes pulverized coal silos of 120 m3 capacity, pulverized coal feeders (fluidized bed rotary pumps), flue gas filter anda 100 m3 ash silo with outloading equipment. Total project cost is DM 5,043 297 including commissioning and test runs. Fuel cost savings of +- DM 784,000 represent 2.5 % 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. Program(-y) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Temat(-y) 7.5 - USE OF PULVERIZED SOLID FUEL Zaproszenie do składania wniosków Data not available System finansowania DEM - Demonstration contracts Koordynator Pfleiderer Teisnach GmbH & Co KG Papierfabrik Wkład UE Brak danych Adres Pfleidererstraße 19 94244 Teisnach Niemcy Zobacz na mapie Koszt całkowity Brak danych
