Feeding the Beast: From Biomass Rags to Carbon Removal Riches

At Charm, everyone likes to talk about pyrolyzers.

How many we will deploy… How fast they will scale… How many tonnes of carbon dioxide removal they will deliver each year…

And those numbers obviously matter, but here is the less obvious fact: if we do not have a corresponding biomass supply to feed the beast, the entire system starves.

No biomass = No bio-oil = No carbon removal.

Charm’s path to gigaton scale is not just about building more pyrolyzers, it’s also about feeding them reliably and efficiently with massive amounts of regionally available biomass. Year after year, Charm must put increasing tonnes of bio-oil underground and, as our deployment expands, pyrolyzers will operate across diverse geographies, running on locally-available agricultural and forestry residues. That means higher tonnages, greater feedstock variety, and significantly more complexity upstream of the reactor. 

The next generation of pyrolyzers is designed for feedstock flexibility and we’re stoked about their ability to run on a wide range of biomass. This feedstock agnosticism will open up more regions of operation and will eventually allow us to effectively maximize machine throughput around variable harvest schedules. Our site is now full of different kinds of biomass as we run through testing different different wood types, wheat straw, corn stover, bagasse and more:

Biomass inventory at Charm CO

As long as the material arrives at the machine with consistent size and moisture content, operators can tune a few setpoints and produce high-quality bio-oil for carbon dioxide removal.

The key words there were “with consistent size and moisture content”. It’s easy to glaze over but that’s the real challenge! It lives before the reactor. Enter: biomass processing. The machines that do it are absolute beasts.

The Reality of Raw Biomass

Biomass does not arrive with a neat, uniform specification. When it leaves the field edge or a forest decking site, it varies widely in:

• Density

• Moisture Content

• Form Factor

• Ash Content

In addition to being completely different from a log, a bale of corn stover is not just a bale of corn stover. It has a broad statistical distribution of plant parts (cobs, stalks, leaves, dirt, rocks, handguns), weather history (and accompanying mildew), soil remnants (sticky clay, coarse sand), and harvesting decisions, all compacted into a cube.

Charm’s biomass engineering team has an obvious, yet complex job: take that always-surprising variability and turn it into chemical-plant consistency. Before biomass reaches the pyrolyzer, it must be transported, dried, and ground to the correct size. Each of these steps consumes energy and burns through operating expenses, pyrolysis performance, and overall project life cycle emissions; as such, they have to be treated as core engineering challenges rather than background logistics. 

Upstream inconsistency becomes downstream instability, and instability does not scale.

Step 1: Over the river and through the woods

Charm continues to develop toward the ultimate goal of pyrolysis at the biomass source. This will ensure that only the densest, most complete product ever needs to be transported. For Charm’s current operations, biomass is transported to our Colorado site in its most dense form to maximize tonnes per truckload and minimize trips: wood arrives as non-merchantable logs that were diverted from pile burns, and corn stover arrives as bales. Material is offloaded and stored in that densified state until processing begins. Fewer truckloads means lower cost and lower emissions, creating an early efficiency gain before mechanical processing even starts. 

Offloaded Log Inventory – material removed from Colorado Front Range forests to reduce risk of catastrophic fire and increase ecological resiliency

Corn stover bale arrival and inspection

As Charm continues its expansion, pyrolysis sites will be positioned as near as possible to feedstock sources, with aggregate throughput sized according to the biomass available within a calculated harvest radius. Transport efficiency is not something to optimize later, it has to be designed into each deployment from the beginning.

Step 2: Breaking up the band

Processing begins by breaking biomass out of its densified form: we need to beat up the biomass and perform rapid disassembly of its natural form so we can efficiently pass air through it. Industrial equipment to the rescue! 

While it can be easy to over-simplify this step into just pummeling the biomass with sharp metal objects, tool selection is actually critical. Different feedstocks respond differently to applied mechanical stress, and they actually dry more easily in our systems at different sizes; an inefficient match between tool and biomass can directly increase grinding energy, limit net throughput, increase losses during subsequent handling steps, and drive excess maintenance and operational expense. 

“The Beast” wood chipper

Forestry residues being chipped to pre-drying form factor in one of our peanut wagons, Marcie (of ‘Peanuts’ cartoon fame)

Due to this inherent link between system economics and tool selection, first cut processing equipment is tested and evaluated based on:

• Energy consumption per tonne

• Particle size distribution

• Throughput capacity

• Long-term reliability and maintenance

To figure out this puzzle, we’ve turned to folks who’ve been handling biomass for a long time: farm and forest implement manufacturers, and the folks who process agricultural crops and forest fiber into value-added products. For wood, we rely on the high velocities and sharp teeth of chippers and horizontal grinders like the Beast for initial size reduction. With the Beast configured for consistent chip sizes we have a good, flowable form factor for drying. When we break stover bales we’re grinding through dryer, softer material that means we need a slower speed to minimize dust generation. Our bale grinder was originally made to feed livestock, but it turns out our pyrolyzer has a similar appetite.  The objective is not simply smaller particles, it’s predictable particles, produced to engineering specs.

Step 3: Physics rules and moisture drools

Moisture content is one of the most important variables in pyrolysis. Excess moisture means energy is spent evaporating water from biomass particles inside the reactor instead of producing valuable bio-oil.

Whenever possible, field drying is leveraged before initial collection. Simply allowing biomass to sit outside in dry weather conditions before transport can cut moisture content by 70% vs. as-harvested baselines.

Moisture analysis of feedstock samples

As biomass moves through Charm’s processing gauntlet, ambient air is used as much as possible where it’s forced through and across wood chips and corn stover using perforated-floor drying wagons. As an added boost, ambient air is combined with recycled heat from our pyrolyzers and - just like that - air temp increases, relative humidity decreases, and the air now has a massive unlock in its moisture-carrying capacity. Warmer air can hold more water, and that simple thermodynamic reality does a surprising amount of heavy lifting. We typically remove 90+% of moisture from our woody biomass and 20% from our corn stover material, targeting a final pyrolysis-ready moisture content of 6-10%. Gotta love physics.

Step 4: The perfect grind

After drying, biomass undergoes a final size reduction step to meet the pyrolyzer’s particle size specification for maximum bio-oil production efficiency. One step shy of becoming a paste.

• For wood, a traditional hammermill is effective

• For corn stover, sharper blades deliver better performance, but the ash accelerates dulling!

Dry biomass is significantly less energy-intensive to grind, which is why our final milling step comes after our rigorous drying procedures are complete. To make sure we have effective downstream pyrolysis performance, we grind to a 2-3 mm particle size target before we give feedstock the chef’s kiss. 

Final dry, ground biomass ready for pyrolysis

Finished material is conveyed into inventory storage vessels, ready to feed the pyrolyzer and ready to transform into durable carbon removal.

Fueling the Future with Flexibility

Transport, drying, and grinding represent the major energy inputs upstream of pyrolysis. Each step is continuously evaluated for efficiency improvements because small percentage gains compound quickly at scale.

As Charm assesses new locations and feedstocks, lessons learned and an expanding library of equipment configurations help ensure that each type of biomass is processed as efficiently as possible. Once material reaches the pyrolyzer within specification, corresponding pyrolysis recipes can be optimized through operational tuning without mechanical redesign. 

No matter the starting form, consistent biomass fed into the pyrolyzer leads to consistent oil (woody pine on the left, corn stover on the right)

Feedstock flexibility is powerful and enables each pyrolyzer to consume whatever biomass is locally available, whether or not that availability shifts by geography or season. Charm can support year-round carbon removal while unlocking a scaling factor that is achieved not just through larger machine deployment, but through adaptable systems designed for real-world variability.

Everyone likes to talk about how many pyrolyzers will be deployed, but gigaton scale will ultimately depend on something far less photogenic and far more fundamental: a steady stream of well-prepared biomass, arriving day after day, in spec, and on time.

No biomass = No bio-oil = No carbon removal.

Fortunately, this is “just an engineering problem” and at Charm, we love those.