The use of energy resources at enterprises producing ethanol, in particular “heat” and “cold,” play an important role in determining the cost of production and the price of the finished product.

The most effective method of heat recovery is “heating” the distillation column (DC) with alcohol steam from the distillation column (RC). This method works as follows: alcohol steam from the boiler is supplied to the annulus of the recuperative boiler of the boiler; stillage from the bottom part of the DC is supplied by a circulation pump first to the pipe space of the recuperative boiler of the DC, which is also a reflux condenser of the DC, and then to the pipe part of the live steam boiler of the DC. Next, it is fed into the bottom part of the DC for further heating of the stillage to the required temperature and cooling (condensation) of alcohol vapor in the DC.

For force majeure and commissioning modes, live steam boilers are installed. Alcohol vapor condensate (reflux) is fed to the upper plate of the water chamber.The prerequisite for this method of “heating” is the operation of the columns under different pressures: the distillation column is under low pressure (vacuum), and the rectification column is under excess pressure.The use of reheating is also supported by the fact that this heating method saves thermal energy and cold and reduces the cost per unit of production.

Consider an example of regenerative “heating” for a plant with a capacity of 3000 dal/day

The total energy consumption of the two columns is 46 kg/dal of thermal energy from live steam and 42 kW/dal of cold energy from recycled water.

Working according to a recuperative scheme (using secondary heat) allows you to save thermal energy in the form of high-temperature steam for heating the distillation apparatus and part of the energy for cooling the distillation column.

The total energy consumption in two columns with a recuperative scheme is as follows:

• Thermal energy in the form of high-temperature steam 26kg/dal;
• cooling - 26 kW/dal of circulating water.

This means that in a distillation column-distillation column connection, the energy that is saved only by using preheating is as follows.

• Thermal energy of live steam 20kg/dal;
• 16kW/gave “cold” from recycled water.

This method of heat recovery between the rectification and distillation columns was implemented at Uzlovsky Alcohol Plant LLC. This made it possible to reduce heating steam consumption and, accordingly, fuel consumption by 30%.