Turning biogenic CO2 into dry ice: How circular carbon lowers costs and footprints

Dry ice is a workhorse across food logistics, e‑commerce, pharma cold chains, and industrial cleaning. Traditionally, most dry ice is produced from fossil‑derived CO2 captured at ammonia or ethanol plants. But there’s a better, more circular route: using the biogenic CO2 recovered during biogas upgrading. In this post, we unpack how it works, what to watch out for on quality and safety, and why co‑locating dry ice with biomethane production can transform the economics and sustainability of your site.

From raw biogas to two valuable products

Raw biogas from anaerobic digestion typically contains methane (CH4) and carbon dioxide (CO2) as major components, with trace impurities like hydrogen sulfide (H2S), moisture, oxygen, nitrogen, siloxanes, and volatile organic compounds (VOCs). To inject biomethane into the grid or use it as vehicle fuel, the CO2 has to be removed in an “upgrading” step. Common technologies include membranes, water scrubbing, pressure swing adsorption (PSA), and chemical solvents.

The upgrade produces two streams:

• High‑purity biomethane (Bio‑CNG/Bio‑LNG)

• A concentrated biogenic CO2 off‑gas

Rather than venting or just vent‑to‑flare, that biogenic CO2 can be polished, liquefied, and converted into dry ice, creating a second revenue line from the same feedstock while displacing fossil CO2 in downstream markets.

What It takes to reach food‑ or pharma‑grade biogenic CO2

Dry ice used for food handling or life‑science logistics must meet strict purity specifications. When starting from biogas, the polishing train is designed to reliably remove:

• Acid gases: H2S and SOx to very low ppm or ppb ranges

• Moisture: to deep‑dry levels (very low dew point) to prevent ice formation and corrosion

• Oxygen and nitrogen: controlled to spec limits

• Siloxanes and VOCs: captured via adsorbents and cold traps to avoid residues in product

• Particulates and oils: via coalescing filtration stages

A typical polishing and liquefaction sequence looks like this:

1. Bulk impurity knock‑out (H2S removal, deoxygenation where needed)

2. Drying (refrigeration and/or desiccant)

3. Adsorption (activated carbon, specialty media for VOCs/siloxanes)

4. Compression and refrigeration to condense CO2 to liquid

5. Fine filtration before storage and distribution

With the correct design and monitoring, CO2 from biogas upgrading can meet stringent food/pharma specifications, opening the door to high‑value applications.

From liquid CO2 to dry ice: The core mechanics

Dry ice production starts with liquid CO2 stored under moderate pressure and low temperature. Inside a pelletizer or block press, the liquid is expanded to CO2 snow and then mechanically compressed into the final form:

• Pellets (3 mm to 16 mm) for cold chain packaging

• Slices and blocks for longer‑duration hold times

• Rice/mini‑pellets for dry ice blasting (industrial cleaning)

Why co‑locate with biogas upgrading?

1) Lower logistics cost and risk
Transporting liquid CO2 is energy‑ and cost‑intensive. Making dry ice where the CO2 is generated eliminates a large fraction of tanker miles, shielding you from market volatility and supply interruptions.

2) Energy integration
Upgrading, compression, and liquefaction create opportunities to share utilities (cooling water, chilled glycol, heat recovery). Smart integration reduces the site’s overall kWh per tonne of product and helps stabilize operations in hot weather.

3) Revenue stacking
You monetize two product streams, biomethane and CO2, off the same digestion asset. Dry ice margins can be attractive, especially in regions with tight CO2 supply or strong demand from e‑commerce, food processors, and vaccine logistics.

4) Carbon footprint and story
Using biogenic CO2 avoids the fossil origin of conventional supply. In many jurisdictions, this supports lower Scope 3 emissions for your downstream customers and aligns with corporate net‑zero roadmaps.

Key design considerations

Feed variability. Biogas composition moves with feedstock, digestion temperature, and plant loading. The polishing train should be robust to seasonal swings and spikes (e.g., sudden H₂S peaks after feed changes). Buffer storage and process control help maintain consistent CO2 quality.

Quality management. Install on‑line analyzers for moisture, oxygen, and key contaminants; implement a sampling plan for detailed spec verification. Quality documentation (lot traceability, certificates of analysis) is critical for food and pharma customers.

Safety first. CO2 is asphyxiating at high concentrations. Designs must include gas detection, ventilation, confined‑space controls, and emergency procedures. For cryogenic sections, protect personnel from cold burns and manage pressure relief paths.

Utilities and footprint. Liquefaction and dry ice production require power and cooling. Correctly sizing compressors, condensers, and chillers, and recovering heat where possible, keeps OPEX in check. Pay attention to water quality for cooling systems to avoid scaling.

Product formats and packaging. Match pellet sizes and block formats to local demand. Invest in insulated boxes, bins, and last‑mile handling to preserve product quality and reduce sublimation losses.

A typical process flow at a co‑located site

1. Upgrading: Membrane or PSA removes biogenic CO2 from biogas to produce biomethane.

2. CO2 polishing: H₂S removal, deep drying, VOC/siloxane capture, non-condensable gas stripping.

3. Compression & liquefaction: CO2 is condensed and stored as liquid.

4. Dry ice production: Liquid CO2 expands to snow and is pressed into pellets/blocks; flash gas is recovered.

5. Storage & dispatch: Insulated containers, route planning, and customer delivery.

Economics in brief

• Capex vs. trucking: On sites with steady biogas throughput, in‑house CO2/liquid/dry ice often outcompetes buying delivered CO₂, especially when regional supply is tight or transport distances are long.

• By‑product value: If dry ice demand is highly seasonal, consider additional CO2 outlets (greenhouses, beverage, pH control) to keep utilization high.

Sustainability benefits that customers can count on

• Displacing fossil CO2: Recovered biogenic CO2 replaces fossil CO2 that would otherwise come from ammonia or natural‑gas reformers.

• Shorter supply chains: Fewer tanker miles and lower transport emissions.

• Waste‑to‑value: Turning a previously vented stream into a certified product.

Getting started: Practical steps for project developers

1. Map demand within 150–250 km. Identify cold‑chain hubs, food processors, and industrial users.

2. Audit your gas. Measure variability and impurity profiles over time to right‑size polishing media and analyzer suites.

3. Design for availability. Redundancy in critical equipment and a service plan keep uptime high through seasonal peaks.

4. Plan utilities and integration. Heat recovery from compressors, shared cooling, and correct insulation pay for themselves quickly.

5. Build the quality system. SOPs, training, and documentation open doors to higher‑value markets.

Key summary for turning biogenic CO2 into dry ice

Converting biogenic CO2 from biogas upgrading into dry ice turns a compliance requirement into a profitable, climate-friendly opportunity. By capturing and polishing CO2, producers unlock a new revenue stream while reducing reliance on fossil-derived supplies. Co-locating dry ice production with biomethane plants improves efficiency, cuts transport costs, and strengthens local supply security. At the same time, this approach lowers emissions and advances the circular carbon economy. With Solveno’s CO2 recovery systems, operators can deliver certified biogenic CO2 products on-site while driving both sustainability and growth.

Want to turn your biogenic CO2 into dry ice? Contact us to learn how Solveno technologies can help you transform your biogenic CO2 to dry ice using our CO2 recovery systems.

For more information:

• Solveno Technologies | CO2 Recovery from biogas upgrading
• Food and beverage gases - EIGA : European Industrial Gases Association
• Doc_125_20_Guide_to_the_Supply_of_Gases_for_Use_in_Foods