What is the significance of the mixed gas-cooled and direct-cooled process?
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A project we designed recently uses a combined intercooling and direct cooling process to cool the gas. However, the gas outlet temperature from the horizontal tube pre-cooler is 30 degrees, so we would like to ask everyone: what is the significance of using this combined intercooling and direct cooling approach for gas cooling?
I would like to ask the original poster: Was this design your own idea or that of the manufacturer?
In coke ovens, inter-tube cooling is generally used; the direct cooling process offers particular advantages in processes involving top-charging of coal, high-pressure ammonia water, and smokeless coal charging. However, the direct cooling process causes significant pollution. This post was last edited by Dylan_soi on 2009-3-21 14:46]
The gas coming from the gas collector is almost saturated with water vapor; the enthalpy of this water vapor accounts for about 94% of the total enthalpy of the gas. Therefore, most of the heat released during the cooling of the gas at high temperatures is due to the condensation of water vapor, resulting in a high heat transfer coefficient and thus high cooling efficiency. Therefore, indirect cooling should be used during the high-temperature cooling stage of gas. During the low-temperature cooling phase, the water vapor content in the gas decreases significantly; meanwhile, the condensation of naphthalene can easily cause equipment blockages, making direct cooling an appropriate approach.
So I want to ask, what is the boundary between high and low temperatures?
The general limit is kept between 50-55°C.
I saw it stated in the books as well, but our current situation is that the amount of deep well water available for direct cooling is limited; it’s possible that we can only handle gas at a temperature of 30 degrees. Is it still meaningful to use this process under such circumstances?