Determination of Nonsulfate Particulate Matter From Fluid Catalytic Cracking Units
This method is for the determination of nonsulfate particulate matter (PM) from fluid catalytic cracking units. Particulate matter is defined as any material that condenses at or above the filtration temperature in the method. This method is similar to Method 5. The main difference between the methods is the temperature the filter is maintained at during collection, rinsing with water instead of acetone, and analyzing a portion of the sample by ion chromatography (IC) for sulfate.
Samples are collected isokinetically from a source on a pre-tared (to a constant weight) glass fiber filter containing no organic binders maintained at a temperature of 160 ± 14°C (320 ± 25°F). A Method 5 train consisting of a heated probe, heated filter, and series of impingers. The first two impingers are filled with 100mL of water, the third impinger is left empty, and the fourth impinger is filled with 200-300g of silica gel.
The filters used for sample collection must be dessicated for at least 24 hours at a contant temperature (20 +/- 5.6°C) and pressure to a constant weight (less than or equal to a 0.5mg weight change to the nearest 0.1mg) and pre-tared prior to use. The filter must have a 99.95% efficiency on 0.3 micron dioctyl phthalate smoke particles.
Once the sample has been collected, the filter is removed and placed in a petri dish. If it is necessary to fold the filter, make sure the PM is on the inside of the fold. This is container 1. Container 2 consists of the PM brushed from the probe, probe assembly and front half of the filter holder and the corresponding water rinse. The volume of the impinger contents is recorded and the silica gel is weighed to determine the moisture content of the stack gas. The impinger contents are typically not analyzed. At the laboratory, the filter is cut into pieces and refluxed with water for 6-8 hours, the probe rinses from Container 2 are then added. Once the solids have settled, two aliquots are taken and analyzed by IC for sulfate (duplicate analysis is required). The duplicate results must agree within 5%.
The remaining contents of the sample are evaporated at 105°C to approximately 100mL, neutralized with ammonium hyroxide (NH4OH), returned to the over, evaporated to dryness, and dessicated to a constant weight. The weight of sulfate is calculated as ammonium sulfate and subtracted from the total PM weight. The result is the nonsulfate PM.
(EPA 40CFR Part 60 Appendix A)