OCR Text |
Show 4 TEST FACILITIES Fig .4 shows the schematic flow diagram of a 1.2MWt test facili ty . The furnace was of a tunnel type and it I s dimension was 1 . 3m in inner diameter and 7 . 5m in length. The inner wall of the furnace was covered with fire bricks and/or refractory wall for Simulating f lame temperature as an actual furnace . The observation ports were provided along the furnace axis for the measurements of f lame behavior and temperature. The furnace was divided into two region; firing region and heat recovery region. The recycled flue gas was extracted from the flue gas duct at the exit of a bag-filter and was boosted up through a fan (GRF) to supply as a part of the oxidant. A part of the recycled flue gas was used as a transport medium of pulverized coal on a primary stream . Pure oxygen, of which purity was 99 . 6%, was supplied from an oxygen storage and supply system, which included a liquefied oxygen storage tank , an evaporator, an oxygen piping, instruments and related valves . N2 gas, which was also evaporated from a liquefied nitrogen bottle, could be added to pure oxygen to adjust oxygen purity attained on a practical large-scale air separation system. Oxygen was mixed with the recycled flue gas and was supplied to a burner on a secondary stream through a tubelar type heat exchanger (normally used as an air preheater). A part of oxygen , as a tertiary stream, was also directly supplied to the burner throat through an 02 injection nozzle. The flow rate of the tertiary stream was controled and measured, independently. Raw coal was ground by a pulver izer to 70% pass through a 200-mesh (74 micron meter) sieve, and was stored in a storage bin . Then , it was transported to the burner through a gravimetric type coal feeder , on the primary stream . The general arrangement of the burner is shown in Fig.5 . The burner was of high swirl type . equipped wi th the adjustable register vanes . Warm-up oil was fired through a fuel oil atomizer . installed at the center of the burner. The 02 injection nozzle was inserted to the center of burner . |