Recycling Duratherm S A silicone based fluid that is ideally suited for high oxidation

1. Introduction

Duratherm S is a silicone based fluid that is ideally suited for high oxidation or completely exposed systems. Duratherm S is virtually stable to oxidation at temperatures under 204°C (400°F) and offers superior protection from fluid degradation.

Duratherm S is best suited for applications which are not sensitive to contamination or leaking [1].

Duratherm S is ideal for applications such as negative pressure mold heaters, annealing tanks, open bath forming, or any processing equipment where oxidation is prevalent and problematic. Duratherm S resists to the effects of oxidation noted with most other heat transfer fluids. High temperature stability of Duratherm S is maintained up to 315ºC (600°F). This characteristic combined with a low end working temperature of -51°C (-60°F) also makes Duratherm S ideally suited for low temperature applications such as batch processing application requiring a single fluid for both heating and cooling.

2. Duaratherm S characteristics

• Superior oxidation resistance (virtually unaffected)
• Non-fouling – extremely long life
• Low odor
• Non corrosive
• Non hazardous
• Non toxic
• Extremely high working temperature : 315°C (600°F)
• Extremely low working temperature : -51°C (-60°F)

Duratherm S is a high performance, extremely stable, long lasting silicone based heat transfer fluid. Virtually unaffected by oxidation under 204ºC (400ºF), Duratherm S is perfect for use in a variety of applications requiring a safe, non-reportable, non-toxic and non corrosive heat transfer fluid.

3. Physical – chemical properties of Duratherm S:

Chemical composition : mixture of siloxanes ( 95 – 99% ) and proprietary additive
( 1 – 5%)

Maximum Bulk/Use Temp. : 316°C
Maximum Film Temp. : 366°C
Pour Point ASTM D445 : -66°C
Flash Point,  ASTM D92 : 324°C
Fire Point ,ASTM D92 : 336°C
Autoignition ASTM E-659-78 : 437°C
Thermal Expansion Coefficient : 0.0991%/°C

4. Recycling Duratherm S

No matter which type of thermal fluid is used, it has to be eventually replaced. When that time comes, there are a few options for disposal and/or recycling.

Petroleum based thermal fluids can usually be mixed with other petroleum recyclable oils such as hydraulic fluids and lubricants. From there various programs are available to recycle or re-purpose these fluids.

There are often local options available but national companies such as ECO USA have programs that will collect the HTF fluids on site and take it to facilities where it’s blended with other recyclable oils for fuel or even re-refined back into a base-oil state for reuse in industrial or consumer products.

Fluids commonly known as synthetic or chemical aromatic thermal fluids need to be handled a little differently. Although some of these can be still be reclaimed, they do need to be segregated and dealt with according to local regulations for disposal. Then there are miscellaneous fluid chemistries such as silicones and glycols.

Typically used drums can be collected by local drum re-conditioners or recyclers, cleaned up and reused.

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