Aerated powder test simulates conditions during drying operations of powder in quantities not exceeding one ton in which a hot air stream flows through the bulk powder.
The glass test cell used for this test is identical to the Bulk Powder test, however, in the Aerated Powder test, an air stream which is at the same temperature as the oven temperature flows at a rate of 0.6 l/min through the sample during the entire test cycle. As in the bulk powder test, the sample temperature is measured at several locations in the cell to detect any exothermic activity and the activity’s onset temperature.
TESTING PRINCIPLE AND METHODOLOGY
A glass cylinder with a height of 80mm and diameter of 50mm that is closed at the base by a sintered glass is filled with the test powder and placed in a uniform temperature oven. The temperature of the oven as well as the powder temperature is monitored at four different heights within the glass cylinder.
The glass cylinder is filled with the test sample and heated by hot air passing through the sample via copper tube into the glass cylinder in a controlled oven. The temperature of the powder sample at different heights and the oven are monitored by using K-type thermocouples. The temperature of the air is controlled by controlling the temperature of the oven.
During the screening test, the oven temperature (air temperature) is increased at a rate of 0.5°C/min to a temperature of 400ᣞC. The isothermal test is based on the onset self-heating temperature obtained during the screening test. The test is repeated successively at different isothermal temperatures until the accuracy is between 2-10ᣞC. The isothermal test is run between 8-24 hours.
Applicable Standard
The powder layer test follows a procedure described by John Abbot in his book ‘’Preventing Fires and Explosions in Dryers’’.
Data Interpretation
If the difference between the onset self-heating temperature of the powder and that of the oven is greater than 30-50ᣞC, exothermic activity is not likely to occur and the test can be stopped.
When to perform Aerated Powder Test
The test is designed to simulate the conditions in dryers, such as through-circulation band dryers and fluid bed dryers, in which a hot air stream passes through the material. This information is vital for determining the operating conditions under which a bulk of powder with air flow through can exhibit exothermic reactions.
Why work with Prime Process Safety Center
- Prime Process Safety Center is a leader in process safety testing with very experienced laboratory personnel. At Prime Process Safety Center our goal is to provide accurate, reliable and defensible data that meets industry and regulatory standards. We understand the need for the quality of your data, and we work assiduously to achieve just that.
- We are knowledgeable and experienced in performing aerated powder tests, ensuring accurate and reliable results.
- We have state-of-the-art aerated powder testing equipment, providing precise and sensitive measurements.
- We follow strict testing protocols and quality control measures to ensure consistent and reliable test results.
- Our team can interpret and analyze the data obtained from the tests, providing valuable insights and recommendations for your specific application or research.
FAQs
What is an Aerated Powder Test?
Answer: The Aerated Powder Test is a method used to evaluate the flammability and explosiveness of fine powder particles when hot air stream flows through the bulk powder.
How does the Aerated Powder Test work?
Answer: In the Aerated Powder test, an air stream which is at the same temperature as the oven temperature flows at a rate of 0.6 l/min through the sample during the entire test cycle. As in the bulk powder test, the sample temperature is measured at several locations in the cell to detect any exothermic activity and the activity’s onset temperature.
What types of industries commonly conduct the Aerated Powder Test?
Answer: Industries handling powders, such as chemical manufacturing, food processing, pharmaceuticals, and those dealing with combustible materials, often perform this test to evaluate the fire and explosion risks associated with airborne powders.
What safety precautions should be considered during the Aerated Powder Test?
Answer: Safety measures, including proper ventilation, controlling ignition sources, using appropriate protective equipment, and conducting the test in a controlled environment, are essential to prevent accidents during the test.
What are the implications of the Aerated Powder Test results for industry?
Answer: Test results provide valuable insights into the potential fire and explosion hazards associated with airborne powder clouds, helping industries establish safety protocols, implement preventive measures, and ensure workplace safety.