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#1 2016-07-15 08:58:13

Registered: 2016-07-12
Posts: 11

Heat Recovery Ideas

Due to the much lower economic value of fuel ethanol, our distillation process must be as efficient as possible. Efficient means HIGH distilled alcohol output with LOW heat energy input.

We absolutely must recover as much heat as possible from the outputs of the process if our project is to be economcally viable. By heat recovery, we mean using heat exchangers to try to transfer the heat of the output products to pre-heat the input stream, thereby saving on the process heat energy needed.

When using a batch still, heat recovery is not easily done. This is one of the big advantages to a continuous still. In a continuous still, there is constant flow of input mash to the process, and this flow can be directed through heat exchangers to pre-heat it.

One obvious places for heat recovery is to recover the heat of condensation of the output product. An even bigger source of waste heat that can be recovered is the spent mash output flow. There is a large volume of this liquid (about 90% of the volume of the mash), and it is hot, nearly boiling temperature. This heat must be recovered if our cost model is to be profitable.

Another wasted heat source is flue gasses for a natural gas, oil, ethanol, or propone fired still. Perhaps half of the heat energy available in the fuel to boil the mash is wasted going up the flue.

Another possible heat source is the boiler itself. Adding insulation will reduce heat losses, and a coil of tubing around the boiler will capture heat lost through the insultaion and pull it back into the boiler.


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