OCR Text |
Show per million (ppm). During transient conditions, a CO spike was registered approximately every 30 min with the levels increasing rapidly to about 700 ppm (l-mi n average) then decreas i ng qu i ck ly. Except for the trans i ent sp i kes, these CO levels are indicative of good combustion conditions. Table 4 also contains the average and range of the THC values for each run. The THC values are calculated as ppm of methane. Runs 1 through 3 showed a steady THC level with averages to 6 to 8 ppm. Run 4 had a slightly elevated THC level of 9 ppm and peaks to 160 ppm during the transient upsets. Runs 5 and 6 had significantly higher THC levels, with an average for Run 5 of 150 ppm and peaks up to 220 ppm, while run 6 produced an average of 110 ppm and peaks to 190 ppm. The cause of these unusually high values for runs 5 and 6 was not identified, however, it was suspected that they related in some manner to operat i on of the natura 1 gas burners. The hi gher THC was largely accounted for by increased methane levels and there was no corresponding increase in CO levels for these runs. EMISSIONS DURING STEADY STATE OPERATION The stack concentrations of volatile organics measured during steady state operation are shown in Table 5. Values for Run 2 are not included because the data for that run were incomplete. All volatile compounds specifically identified by GC/MS analysis of VOST samples or by GC analysis are included in descending order of the average concentration measured. Twenty-nine compounds were identified at concentrations that ranged from 0.1 to 980 ng/L. The total unknowns shown on the last line of the table is an estimate of the total concentration of all compounds detected but not identified. All of these unknown compounds were present in low concentrat ions. Three compounds (methane, chloromethane, and chloroform) accounted for more than half of the total mass of volatile compounds detected. Table 6 shows the estimated concentrations of classes of semivolatile compounds detected during steady state operation. The data are estimates of concentrat ions based on GC/MS ana lys is of samp 1 es co 11 ected wi th a MM5 train. Very few specific compounds were identified and none were identified or detected at concentrations as high as many of the individual volatile compounds. The semivolatile compounds were grouped into five classes; oxygenated aliphatics, chlorinated aliphatics, aromatics, aliphatic hydrocarbons, and unknowns. Compounds were placed in these groups based on interpretation of the analytical mass spectral results. The oxygenated al iphatic compounds comprised the largest group of the classes, both in terms of the total number of speci es (43) and the tota 1 Quant i ty. The next 1 argest group was the ch 1 orinated aliphatic hydrocarbons. The oxygenated aliphatic group includes aldehydes, among other compounds. A speci a 1 samp 1 i ng tra in was used to obta in samples for analysis of formaldehyde and other aldehydes. This analysis showed possible high levels of aldehydes, however, blank levels were sufficiently high to prevent quantitation of the compounds. 4 |