Heat transfer

The goal of a steam system is to transport heat, with as little loss as possible, to different parts of a plant. The global performance of a steam system is thus directly related to the quality of heat transfer in steam processes.

Many factors can negatively affect heat transfer:

  • fouling in heat exchangers
  • noncondensable gases in heat exchangers
  • undersized heat exchangers

Fouling

Fouling in heat exchangers can be caused by corrosion or its corollary: chemical deposits resulting from abusive use of corrosion-control chemicals. Minerals can also build up in heat exchangers.

Corrosion is non-conductive: it degrades heat transfer. Corrosion is caused by noncondensable gases, such as O2 and CO2, which unavoidably enter all steam systems. Since in a Lalonde Systhermique SCCS® noncondensables are eliminated throughout the system, corrosion in heat exchangers is reduced to a bare minimum.

Removing noncondensable gases practically eliminates all risks of chemical buildups since injection of corrosion-control chemicals is also reduced to a minimum.

Buildups of minerals result from a water-softening problem. A well-calibrated water-softening solution will prevent buildups of minerals in heat exchanger.

Noncondensable gases in heat exchangers

Since noncondensable gases are thermal insulators, they are detrimental to heat transfer. This is one more reason to make sure noncondensable gases are eliminated from a steam system.

Undersized heat exchangers

In steam systems, it is not uncommon to find heat exchangers in which the heating surface is not sufficient for the exchanger’s purpose. Often, this happens when, through time, there has been an increase in demand without the heat exchanger being upgraded. Adequate sizing of heat exchangers is essential to insure optimal heat transfer.