OCR Text |
Show Analytical Measurements Gas and solid sampling in the furnace interior and flue was performed using a water-cooled probe (Figure 9) purchased from International Flame Research Foundation (Umuiden, Holland). The sample enters the probe through a stainless-steel tip, is cooled, and then passes through a sintered bronze filter that captures the solid particles. The gas is dried as it passes through a Permapure gas dryer, which reduces the dew point to less than 32°F to minimize S02 and N O x losses. The gas then flows through a Teflon sample line to the analytic instrumentation. The bronze filter is removed and replaced with a clean filter at each sampling point. The following analytical instrumentation equipment was used in the project: • Beckman 742 Polarographic Oxygen (0->) Analyzer • Beckman Paramagnetic Oxygen (02) Analyzer • Beckman NDIR Carbon Monoxide (CO) Analyzer • Beckman NDIR Carbon Dioxide (CO-,) Analyzer • Beckman Chemiluminescent (NO-NO ) Analyzer • Thermo Electron Chemiluminescent (NO-NO ) Analyzer (Lower limit 0.2 parts per billion). The wall temperatures for some tests were measured by wall thermocouples. The solid sample analyses were performed by the IGT Analytical Laboratory for carbon and hydrogen in the fuel and the ash. The method of analysis on the samples was done by a combustion train, in which the sample was first burned in oxygen and the products formed were then quantitatively analyzed. The Fuels Two bituminous coals were fired in this project: a fine-ground coal and standard pulverized coal. Particle Reduction Service Corp. ground a Pittsburgh No. 8 coal to a particle size of 99.9% below 400 mesh (37u) using a hammer mill and an air mill. Proximate and ultimate analysis were performed before and after the grinding of this coal by the IGT Analytical Laboratory (Table 2). Grinding the coal removed about 3% of the volatile matter and lowered all the other elemental concentrations except sulfur. The percentages of ash and sulfur in the coal was increased by grinding, which may be due to the centrifugal size classifier in the air mill. The loss of volatile matter could have been caused by heating the coal during the grinding process. 16-17 |