Patent ID: 7297549
Filing Date: 2007-11-20
Classification: G01N,Y02A,Y10T

Abstract:
1. In an emissions monitoring system, a method of determining bias in a measurement of a constituent concentration level in a sample gas, the method comprising: establishing a sample gas flow from an emission stream into a sample gas line; removing water from the sample gas flow and cooling the sample gas flow to a temperature below about 41° F. to produce a cooled, dried sample gas flow; determining the constituent concentration level for the cooled, dried sample gas flow; introducing a span gas having a known spa gas constituent concentration level into the sample gas flow to form a combined sample and span gas flow the span gas being introduced at a desired span gas flow rate; removing water from the combined sample and span gas and cooling the combined sample and span gas to a temperature below about 41° F. to produce a cooled, dried, combined sample and span gas flow; determining a combined sample and span gas constituent concentration level for the cooled, dried, combined sample and span gas flow; and determining a measurement bias using the known span gas constituent concentration level, the sample gas constituent concentration level and the combined sample and span gas constituent concentration level.