Pumping CO2

Pumping CO2

The Challenge of Pumping Carbon Dioxide

One of the more challenging applications to which we have successfully applied our products is for pumping liquid carbon dioxide (CO2). Being a liquefied gas, it must be transferred at a controlled combination of low temperature and high pressure to minimise vapour formation, whilst its inherent compressibility and low lubricity places special demands on pump design.

The applications for CO2 are many and varied, encompassing nuclear power generation, recirculation in commercial refrigeration plant, use as a blowing agent in foam-making processes and the extraction of essential oils from plant materials. All these applications require a pump that is able to cope with high pressure at the pump inlet, poor lubricity and low temperatures. All of these factors require a high integrity pump design and special attention to correct installation.

Other pump types such as rotary positive displacement pumps struggle with liquid CO2 whereas our triplex positive displacement plunger pumps are able to provide a robust solution. At Cat Pumps, we have developed models and variants that specifically address the many applications for CO2, with fluid heads manufactured from stainless steel for liquid and process compatibility, strength and thermal stability.  Their concentric, high density polished ceramic plungers are abrasion resistant, providing excellent seal life and the specially-selected plunger seals are lubricated by the liquid CO2, so there is no requirement for additional seal flushing liquids.

In order to ensure that operators obtain optimum performance and working life from their pump seals, Cat Pumps’ CO2 pump installations can also incorporate a seal condition monitoring system. This allows the user to constantly check the performance of the plunger seals so that maintenance periods and seal replacement intervals can be predicted.

A number of Cat Pumps model 6861 pumps have recently been installed in the nuclear power industry where CO2 is the primary temperature control medium for advanced gas cooled nuclear reactors during the reaction process. The CO2 used to top up the reactors and refuelling plant is stored in high pressure tanks and our pumps are being used to replenish these from the lower pressure bulk tanks that receive supplies from road tankers.

We know that users of CO2 expect a pump that will give long working life and high of levels sealing integrity at all times and we can offer PD pumps suitable for a wide range of flows and pressures in a variety of industries and applications, incorporating additional features to minimise potential problems with icing.

Application Specification

CO2 Pumping


Cat Pumps Model

6861K ESR


19 bar


105 l/min


Liquid CO2

Duty Cycle



15 kW, 4 Pole, Electric Motor

 View CO2 Pumping Solutions

View Model 6861K Data Sheet 


1 Fleet Business Park
Sandy Lane
Church Crookham
FLEET, Hampshire
GU52 8BF

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F.01252 626655

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