Extraction Chilling System Design Considerations

Extracting cannabinoids has been a growing market for a while now and as more states come online with recreational/medical marijuana programs and CBD based products gain more and more use nationwide this market will continue to grow!  There are dozens of different extraction and solvent recovery methods, all requiring their own special chilling needs.  In this post I am going to specifically discuss ethanol-based extraction and recovery methods.  If your facility utilizes a different method, give us a call and we will help you find a chilling system that works best for you too!

Many ethanol-based extraction facilities desire the ethanol/biomass wash to be very cold (some as low as -80C).  At these temperatures refrigeration cycles lose efficiency rapidly, which results in large compressor motor horsepower requirements for seemingly small loads.  For many small/middle scale producers it remains cheaper to utilize a single chiller system, however for larger producers and some small/middle scale producers there are other options that do make sense.

In many of these facilities the largest cooling load comes from chilling room temperature ethanol down to extraction temperatures.  It is often desired that this be done quickly so that the turnaround for the production team isn’t slowed unnecessarily.  Due to the fact that much of this cooling is happening with relatively warm solvent we can split this chilling load across multiple chillers operating at different temperatures to optimize both the capital and operating cost of the chilling system.  Often times I have seen a 30% reduction in total motor horsepower required and ~25% reduction in capital cost by splitting the system rather than operating with a single chiller operating at the lowest required temperature.  Often times the temperatures that we choose to operate each chiller at are very job specific so feel free to reach out for an optimized chilling system just for you!

Solvent recovery also, often times, requires a decent sized chiller as well.  The upside to these units is that the condensation of ethanol happens at much warmer temperatures (even if the system is running at a deep vacuum) and as such we can utilize higher temperature/efficiency refrigerants.  I have spoken with a fair number of operators that want to run the solvent recovery chiller at a very low temperature to aid in chilling the solvent before it goes back to the extraction side of the process.  I tend to recommend people try not to operate this way.  In these systems up to 90% of the load can be from the heat removal required to condense the solvent.  If we operate the chiller at a temperature significantly lower than this condensation load we will require larger chillers than necessary, which equates to higher capital and operational costs with no increased system throughput.

Needless to say extraction facilities are complex multistep processes that require a solid understanding of the users needs along with a wide array of chiller solutions to be able to design a fully optimized system!  At G&D we have nearly 30 years of experience building chilling solutions across a wide range of processes and have a proven record within the cannabis extraction space.  Reach out with your application so that we can design a system for you!