OCR Text |
Show © SHCT-100 - Figure-5 and Figure-6 show the flow diagram and the furnace of this facility. It is considered as a main object to confirm the effect of different coal types and slurry property upon the combustion characteristics. At a proper distance along the wall there are several observation ports to study the flame condition and also some after air ports to test two stage combutsion. © VCT-3000 - Figure-7 shows the combustion system flow diagram of the multi burner combustion test facility. The furnace is 4.2 m wide, 3.0 m deep and about 16 m high above the ground. The furnace wall has several ports to observe firing conditions and also several ports for char sampling or temperature measurement. Burner arrangement is of opposed firing system with three rows and three stages each in the boiler front and rear walls, respectively. After air ports for two stage combustion are located above the top burners. For the CWM combustion, the slurry was supplied by nine burners in the front wall firing. For the purpose of investigating the burning process, the char sampling was conducted at several points in the furnace. These probes were water quenched type. © HCT-1000 - For the burner scaling-up and the wear problem of the atomizer, another horizontal combustion test facility of which nominal capacity is 1000 kg/h (25 MBtu/h) will be conducted next year. 4. Results and Discussion 4.1 Test Conditions The coal analyses and slurry specifications in the series of preparation and combustion are shown in Table-2. Each of E, S, M and A-coals is a domestic mining coal, and U-coal is mined in the U.S.A.. The SHCT-100 test is performed at the heat input of approximately 1.4 x 106 Btu/h at CWM firing for each coal. For the VCT-3000 test, CWM was supplied to nine (9) burners with the total heat input of about 30 x 106 But/h continuously. 4.2 Preliminary Test (1) Coal and Slurry Properties It is well known that slurry properties depend on the coal type and its properties. Figure-10 shows a relation among the available solid contents of CWM, inherent moisture and Hygroscopic Ratio of various types of coals when the condition of particle size distribution is nealy the same in each CWM. This hygroscopic ratio is defined as the amount of water absorbed by coal, which is determined from the weight difference when about lOg of coal particles 0.5 - 1.0 mm in diameter are soaked in water for 3 hours, then the particles are wiped with filter paper to remove the externally adhered water completely and dried until no decrease in weight is observed. By these results, the properties of CWM are related as a linear function to the inherent moisture of raw coals. Furthermore we have also found out the relationship between the slurry properties and Oxygen/Carbon ratio of raw coal. 4 |