Secondary Heat Use for Chlorine Dioxide (ClO2) Pre-heating

Preheating chlorine dioxide ClO2, which is usually chilled to maximize concentration, before it enters the mixer is an important energy conservation measure as it will reduce steam demand in the bleach plant. Pre-heating can be accomplished using secondary heat sources by installing heat exchangers in the ClO2 feed circuit (Kramer et al., 2009. p.93).

Development Status Products
Commercial
Bleached Pulp

Secondary Heat Use for Chlorine Dioxide (ClO2) Pre-heatingCosts & Benefits

Parent Process: Bleaching
Energy Savings Potential

US flag In one study, for a mill producing 1 000 ADT of bleached pulp, where Kappa value to bleaching is 30, where a ClO2 concentration of 9.5 g/l is used, and where ClO2 is heated from 2.8 to 43.3 C, 0.59 GJ/ADT of energy savings were estimated by using secondary heat in preheating (NCASI, 2001. p. 77).

CO2 Emission Reduction Potential

US flag For the same mill studied a net CO2 reduction of 12 625 t-CO2/year has been estimated.

Costs

US flag For the plant corresponding to 0.59 GJ/ADT saving, annual cost savings of $430 900 (2001 dollars) were estimated. Capital costs are largely due to the cost of heat exchanger and piping (NCASI, 2001. p.77).

US flag

 For another plant, savings in fuel, electricity, and steam were estimated at $61,000, while capital costs were estimated at $124,000 (2003 dollars) ((Kramer et al., 2009. p.93). 

Secondary Heat Use for Chlorine Dioxide (ClO2) Pre-heatingSchematic

Secondary Heat Use for Chlorine Dioxide (ClO2) Pre-heating Publications

Page Number: 

93

Page Number: 

77