There are various possibilities to recover thermal energy from steam and waste heat in the paper drying process. Some of these include the following:

• Replacing the dryers with stationary siphons in the paper machine;
• Mechanical vapor recompression and reuse of the superheated steam in the drying process;
• Use of heat pumps to recover waste heat;
• Recovering heat from the ventilation air of the drying section and using this heat for the heating of the facilities when needed.

On the other hand, the options that can be considered for the direct-fired air dryer hoods, used mainly on tissue and toweling machines, include:

• Recovering the hood exhaust air and using this to preheat the air entering the combustion chamber;
• Employing a cascade system that uses the hood exhaust air to feed the supply fan of the wet section, which will reduce the fuel demand for wet section burners;
• installing an economizer to reclaim heat from hood exhaust air and use it to heat fresh water for high pressure showers of the paper machine felt and wires (Kramer <em>et al.</em>, 2009. p.102).