On heating solid materials with flue gas
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I have a question for everyone. Alumina enterprises. I want to reuse the flue gas at around 170 degrees from the boiler to heat the alumina feedstock. Aluminum hydroxide contains about 10% of adsorbed water. In the silo. I want to modify the silo by connecting a flue directly to it, with the flue gas transferring heat to the alumina powder through the flue wall. Is it feasible? Is the gas-solid heat transfer coefficient very low? If possible, how is the heat transferred by flue gas calculated? Thank you all
This post was last edited by wiseboy on 2015-12-7 at 12:02. This issue falls more under the category of \"solid drying technology\" rather than \"heat exchange technology\". It can be completely solved using dry theory. It is recommended to use the “gas-solid fluidized bed” technology, as it is the most suitable option; of course, the knowledge related to heat exchange systems has its limitations. You can contact me if necessary. If it’s a general question, that’s my answer. “It is certainly extremely inefficient and not feasible for the flue gas to transfer heat to the alumina powder through the flue wall.
Thank you for your answer. It mainly involves minor technical upgrades. I’ve also looked into fluidized beds before; the investment required and the space needed make it impractical to implement them. Are there any other good alternatives?
Absolutely. It should be considered that an excessively long flue with too many bends can affect the operation of the boiler; adding a fan could be an option, but this needs to be done in coordination with the boiler to ensure its proper operation.
Flue ducts for exhaust smoke, to recover waste heat – but how can this waste heat be recovered more effectively? Mainly want to heat hydrogen, oxygen, and aluminum oxide
A direct fluidized bed won’t work; the flue gas contains nitrogen and sulfur compounds, which will react with aluminum oxide hydroxide, especially in the presence of water. The heat exchange efficiency in such a setup is too low, making it practically useless. If an air heat exchanger is used before drying, the problems related to air still remain. Try making an alumina hydroxide chute with a cavity at the bottom through which flue gas passes; let the alumina hydroxide powder flow down in a thin layer on top. The cost is not high