Reducing energy requirements

Energy reduction can be achieved in several ways:

Good "house-keeping" Energy may be wasted from leaking valves on steam-pipes, inadequate insulation on reaction vessels or pipes, or other poorly maintained equipment. On a large site better maintenance routines may save a significant amount of energy.
Heat recovery Use can be made of the energy removed from exothermic reactions. It may be used as an energy source in another process, or to provide hot water and heating for other site facilities

Hot flue gases can also be used to heat water before venting to the atmosphere, or where waste gases are flammable they can be used as a fuel to produce steam.
Reaction choice and conditions Choosing a reaction that works at lower temperatures may save energy. Biosynthesis usually works at much lower temperatures, though energy needed for product separation may be much higher

Reactions frequently need high temperatures, but process optimisation may result in changes to temperature, pressure or the catalyst that result in lower energy requirementsIn some cases using oxygen rather than air helps reduce energy. This is because raising the temperature of the nitrogen that makes up 80% of the air still requires energy, but yields no product.
Combined Heat and Power (CHP)

Many manufacturing sites generate their own electricity, rather than buying from the grid. This is more efficient as it eliminates transmission losses, and the heat generated can be used on site for many different purposes from pre-heating reactants to keeping offices warm.

photo: energy recovery unit
photo: an industrial heat exchanger

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