Method 3 : Gas Analysis for the Determination of Dry Molecular Weight
This method pertains to the determination of CO2 and O2 concentrations and dry molecular weight of a sample from an effluent gas stream of a fossil-fuel combustion process or other process.
In this method, a gas sample is extracted from a stack by one of the following methods:
- Single-point, grab sampling
- Single-point, integrated sampling
- Multi-point, integrated sampling
The gas sample is analyzed for percent CO2 and percent O2. For dry molecular weight determination, either an Orsat or a Fyrite analyzer may be used for the analysis.
The sampling apparatus required for this purpose must be capable of obtaining a representative sample and maintaining a constant sampling rate, and should be otherwise, capable of yielding acceptable results.
The required equipment is shown in the table below.
| Type of sampling → Equipment ↓ |
Grab sampling | Integrated Sampling |
| Probe | Stainless steel or borosilicate glass tubing equipped with an in-stack or out-of-stack filter to remove particulate matter (a plug of glass wool is satisfactory for this purpose). | |
| Sampling Pump | For transport the gas sample to the analyzer. | A leak-free, diaphragm-type pump, or equivalent, to transport sample gas to the flexible bag. A small surge tank between the pump and rate meter needs to be installed to eliminate the pulsation effect of the diaphragm pump on the rate meter. |
| Flow Rate Meter | Not required | Range : A flow rate range of 500 to 1000 ml/min is suggested. Accuracy : ±2 percent of the selected flow rate. |
| Flexible Bag | - | Any leak-free plastic : Tedlar, Mylar, Teflon or plastic-coated aluminum Suggested capacity : 55 to 90 liters (1.9 to 3.2 ft3) Leak rate : within specified limits |
| Pressure Meter | - | For flexible bag leak-check. |
| Vacuum Meter | - | For sampling train leak-check. |
| Combustion gas analyzer | - | Orsat or Fyrite type analyzer |
We manufacture and / or supply all equipment required for implementation of Method 3 and much more.