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Green Liquor: Recausticizing using Direct Steam Injection

Green Liquor

Flow Rate:
300-800 GPM [82-218 m³/hr]

Inlet Temperature:
140°F [60°C]

Discharge Temperature:
190°F [88°C]

Fluid Supply Pressure:
40 PSIG [3 barg]

Steam Supply Pressure:
150 PSIG [10 barg]











Green Liquor: Recausticizing


Who was the Recausticizing Plant?

A former Nekoosa Packaging Corporation in Valdosta, Georgia, USA, needed to eliminate hammering and scaling problems exhibited by existing green liquor heater.


What Recausticizing Issues Were They Facing?

Nekoosa has been using an externally modulated direct contact steam heater, mass steam flow rate was controlled by varying the pressure of the steam with an external control valve. The resulting pressure variations of the steam resulted in a reduced range of stable operation. When the heater was operating outside the limited range of stability, the heater exhibited severe hammering and vibration with consequent damage to internal components.


Solutions Using a Hydroheater

Hydro-Thermal engineers installed the K414AN Hydroheater prior to the slaker in order to precisely control temperature and maximize the conversion efficiency of slaked lime.

Installed in 1989, the mill reported that all hammering and vibration had been eliminated. The temperature of the green liquor had been precisely maintained at 190°F [87.8°C], and the Hydroheater has operated without scaling or fouling.

Update: Regular maintenance can provide years of service even in a corrosive environment. The mill carries a spare heater for easy swapout and uses a 2-3 year rebuild schedule to replace internal wear components. The current heater is on the fourth rebuild and has been in operation for 12 years.

Goal of Recausticizing Case Study

• Eliminate hammering and scaling
• Achieve stable operation
• Reduce maintenance


• Consistent stable operation
• Eliminated scaling and hammer
• Heater has been in operation for 12 years


To learn more related to this case study, head over to our pulp & paper pages to get more information on everything related. Discover similar processes within those industries and be able to find more solutions for common industry heating issues.


Are you curious about our patented direct steam injection technology? Click here to learn more.

Are you wondering what applications are ideal for direct steam injection? See the Where It Works section for the a list of industries.

Do you want to learn more about our products? Click here for more information.

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Hydro-Thermal is the global leader in the development and manufacturing of Hydroheaters. Through our vast global channel partners, we support hydro heating in six continents and all industrialized areas. We create heating systems for a variety of industries including: pulp, paper, chemical, ethanol, food & beverage, metal, & more!

Hydro-Thermal Corporate 

400 Pilot Court
Waukesha, WI 53188 USA
Phone: (262) 548-8900
Fax: (262) 548- 8908