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Direct Contact Columns

Direct Contact Columns: Recover Waste Heat and Decrease Steam Use

I already have heat recovery on my boiler exhaust…

Many boiler systems take advantage of the heat present in exhaust in a feedwater economizer, which preheats feedwater entering the boiler with hot gasses exiting the stack.  However, conventional economizers are typically limited by the minimum exhaust temperature to avoid condensation from occurring in the boiler stack.  While many condensing exhaust systems exist, the challenge is in finding an economical option with a long equipment lifespan. 

What is a direct contact column?

Most boiler inefficiency is the in the form of stack losses as hot water vapor, largely from combustion, leaves as exhaust.  Direct Contact Columns (DCCs) offer an excellent opportunity to recover this waste heat through direct contact of the exhaust and water. The latent heat present in the exhaust is captured to produce a hot water loop.  The water is then sent to an exchanger where it can indirectly transfer heat to offset steam or hot water, before being returned to the column. DCCs are typically suited for low grade heat needs, as they can generally produce water between 130 to 140 degrees Fahrenheit.  

Are DCCs only for boiler systems?

No! Kinergetics DCC systems are generally more cost effective than condensing economizers, and have a lower pressure drop with fewer concerns of plugging and fouling due to their open column design.  This also means that they are applicable to exhaust streams that are typically too dirty for heat exchangers or columns with mass transfer packing.  Kinergetics can provide custom columns to meet your application. For a system installation example, see here.