Flex Energy gas turbines power mobile hemp dryers

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FlexEnergy Inc. Channel Partner MBS Engineering (in San Ramon, CA) has designed a mobile natural gas-powered hemp drying unit, utilizing the Flex Energy GT333S model gas turbine generator. MBS, using Flex turbines, will be the exclusive manufacturer of commercial mobile hemp drying units, to be used and sold by a large-scale Oregon-based commercial hemp grower, TumbleWeed. The unit, which is enclosed in a semi-trailer, is called the 'Black Hemp Box', and is capable of drying 75,000 lbs. of wet hemp per hour (altering it from 70% water to 5% water as it is prepared to be pressed for distillation and accretion of CBD oils).

While hemp has historically been used for products like textiles, rope and clothing, it can be used for plastics and even biofuels. It has come to prominence lately for yielding CBD extract, a substance used to manage pain, inflammation, and symptoms of neurological disorders, and which - unlike THC harvested from marijuana - is not mind-altering. With large-scale pharmaceutical growing operations entering the industry alongside even smaller growers, industry experts predict commercial CBD sales to approach $20B annually in the next few years. Black Hemp Box is intended to allow growers to keep power generation infrastructure (and therefore costs) to a minimum by allowing the redeployment of costly dryers to different regions, as the harvest or need dictates - within or between multiple growing operations.

The process of extracting CBD oil from hemp requires that moisture be removed from harvested hemp before the dry plant matter is pressed. This drying process consumes significant amounts of thermal energy, to vaporize and expel water, in addition to electricity to power conveyors, separators, and other production machinery. Gas turbines are ideal because they produce both thermal and electrical energy: besides 'keeping lights on', 'waste' heat  from gas turbines can be harvested to heat (and dry) plant matter. This dual power profile is called 'cogeneration’ and brings gas turbines close to 90% efficiency. Cogeneration or CHP (combined heat and power) from gas turbines is such an efficient and eco-friendly option for power generation that - when thermal loads are part of the power generation profile - the Department of Energy and the Environmental Protection Agency advise them. Gas turbines are ideally suited for operations that cannot afford 'grid down' scenarios. “It’s no secret that industry and the commercial sectors are highly vulnerable to large-scale utility power outages from circumstances such as technical power failures, system overload, cyber-attacks and severe weather,” said Mark Schnepel, President of FlexEnergy. Gas turbine generators can generate power 'off the grid' and are more disaster resilient than grid electric but do require a piped (gas) fuel source. Flex Turbines use the widest range of gas tolerance available and the Black Hemp Box contains its own fuel.


While the technical details of the Black Hemp Box are proprietary, the unit sits inside a black semi-trailer, and is comprised of a power/heat-generating unit and a drying unit. Power comes from a Flex Energy GT333S with an electric starter, and the power profile is both electrical and thermal. The turbine is fueled by an onboard liquid propane gas (LPG) fuel tank and is housed in an exterior 'blanket' or heat recapture shell. Ducting moves hot air and mass flow to the drying unit for the drying process, which consists of a hopper and conveyor, and super-heated air dries (but does not burn) plant matter. Assembly is minimal, as the point of the mobile hemp dryer is to permit rapid pack-up and redeployment, with minimal downtime or technical requirements.

Static gas turbine generators are already a popular option for cannabis grow rooms and greenhouses. “[G]rowers are paying approximately $150,000 a month for 1.3 megawatts of power from the grid. Our off-grid solution delivers power at about half that cost with the turbine financing and gas supply combined.” James continues, "We hope to make the gas turbine option still more appealing by adding 'location flexibility' to that list of benefits."