Scope: 

The ASTM D6137 test technique for sulfuric acid resistance of polymer linings for flue gas desulfurization systems is a standard test method. The purpose of this test method is to determine the combined effects of heat and sulfuric acid exposure on a lining system applied to a carbon steel substrate. This test method examines the primary failure mechanisms of linings when they are applied on square test panels and cycled from ambient temperature to a predetermined increased temperature. For ASTM D6137, the recommended test temperatures of 200°F and 350°F are based on average maximum working zone temperatures in flue gas desulfurization systems. 

Test procedure:

The oven is preheated and the lower portion of the test panel is immersed in sulfuric acid for one hour for the ASTM D6137 test. The test panel is then removed and dried properly at laboratory temperature for about 15 minutes. The test panel is then vertically placed in the preheated oven and left there for 15 to 17 hours. After each exposure interval, the panel is removed and set aside to cool. The cycle starts all over again. The panels are examined and the findings are recorded after 1, 2, 5, 10, 20, and 30 cycles in line with ASTM D6137. Depending on the panel state and test objectives, the test may be stopped after 30 cycles or as required. 

Video 01: How flue gas desulfurization (FGD) works

Specimen size:

According to ASTM D6137, the test panels used in the technique must be new and made of commercial quality carbon steel with a minimum thickness of 6-mm and a square size of 200 mm. 

Data:

The ASTM D6137 test results can be combined with other test techniques to choose a liner for surfaces in flue gas desulfurization (FGD) systems that will be exposed to hot unscrubbed flue gas or scrubbed gas that has been warmed considerably above the water dew point.

Conclusion:

The ASTM D6137 test technique for sulfuric acid resistance of polymer linings for flue gas desulfurization systems is a standard test method.