Low-Cost Strategies for Pressurizing CO₂: Best Practices & Cost Benchmarks

Best low-cost way to pressurize CO₂

Pump it as a liquid whenever you can (and only compress as a gas when you must). The physics is simple: once CO₂ is condensed, the specific work to raise pressure is ~ΔP/ρ, which is tiny compared with gas compression work. In practice, the cheapest configurations are:

1. Hybrid compress → condense → pump (most practical overall)

Use a multi-stage intercooled gas compressor only up to the point where CO₂ can be condensed (near/just below the critical region), then finish the pressure rise with a liquid CO₂ pump to your pipeline/storage pressure (e.g., 110–150 bar). This “pump last” step cuts the energy penalty vs. all-gas compression. ([Global CCS Institute][1])

2. All-liquid pumping (cheapest per bar, but only if you already have liquid)

If your process already provides liquid CO₂ (e.g., a cold, condensed product stream), a cryogenic liquid CO₂ pump can take it to 100–350 bar with very low power compared with gas compression. (These are commodity machines in cylinder-filling and industrial-gas service.) ([CNC D Cryogenic Tank][2])

Why this wins: for a pump raising liquid CO₂ from 70 → 110 bar, the specific work is roughly

$w approx Delta P/rho sim 4times10^6 text{Pa}/900 text{kg·m}^{-3} approx 4.4times10^3 text{J·kg}^{-1}$

≈ 0.0012 kWh/kg = 1.2 kWh/ton—orders of magnitude below gas compression. (That relation is the standard flow work $Pv$ result.) ([Pressbooks][3])

What gas-only compression costs you (for context)

Authoritative CCS references put gas compression to ~110 bar at roughly 0.4 GJ/ton ≈ 111 kWh/ton (before transport/storage). At $0.10/kWh, that’s about $11 per ton of CO₂ just for compression. ([IPCC][4])

With good design (multi-stage, aftercooling, optimized staging), that number can be trimmed, but it’s still in the ~90–140 kWh/ton band for many cases—again, $9–$14 per ton at $0.10/kWh. ([Global CCS Institute][5])

What liquid pumping costs you

As shown above, pumping the last 40 bar (70 → 110 bar) as a liquid is roughly 1–2 kWh/ton, i.e., $0.10–$0.20 per ton at $0.10/kWh—two orders of magnitude cheaper per bar than gas compression. Commercial LCO₂ pumps are widely used for exactly this reason. ([CNC D Cryogenic Tank][2])

> Caveat: you must condense CO₂ first. Condensation removes latent heat (order ~180 kJ/kg near ambient), which is thermal load, not pure electric compression work. If you’re already rejecting that heat (e.g., as part of your capture/liquefaction train), the marginal electric cost of the pump step remains extremely low. ([Engineering ToolBox][6])

Recommended low-cost architecture (ranked)

1. Hybrid compressor + condenser + liquid pump (dense-phase outlet)

Multi-stage centrifugal/reciprocating compressor with intercooling, condense near the critical region, pump to final pressure. Multiple independent studies and industry design guides show this reduces overall power vs. all-compressor trains. ([Global CCS Institute][1])

2. All-compressor train (when condensation isn’t feasible upstream)

Use multi-stage with aftercoolers; consider suction cooling and optimized staging—papers show hundreds of kW saved at scale by suction cooling and staging tweaks. Expect ~100±30 kWh/ton to ~110 bar for typical CCS feeds. ([DIVA Portal][7])

3. All-liquid pump (when LCO₂ is already available)

Cheapest incremental pressurization. Off-the-shelf LCO₂ pumps to 100–350 bar are common (beverage, food, industrial gas). ([Giant Pumps][8])

Back-of-envelope dollars at $0.10/kWh

Gas-only to 110 bar: ~111 kWh/ton → $11/ton (typical literature value). ([IPCC][4])

Hybrid: compress to ~70 bar, condense, pump to 110 bar:

Gas compression cut (lower ratio) + LCO₂ pump (≈ 1–2 kWh/ton for last 40 bar → $0.10–$0.20/ton); total is meaningfully lower than gas-only. Exact saving depends on your condenser duty/heat sink. ([ScienceDirect][9])

Pump-only (you already have LCO₂):

1–5 kWh/ton to add tens of bar → $0.10–$0.50 per ton typical. Vendor specs corroborate small motor powers at high discharge pressures for meaningful flows. ([Giant Pumps][8])

Practical notes (design choices that save money)

Intercool aggressively between compressor stages; it cuts gas specific work and enables easier condensation downstream. ([DIVA Portal][7])

Stage count & pressure ratios matter—optimize per duty and ambient sink. (Large studies benchmark this for CCS pipelines.) ([MDPI][10])

Handle near-critical behavior carefully (materials, seals, control) as CO₂ crosses 31 °C/73.8 bar. Use proven dense-phase practices from CCS/pipeline design. ([netl.doe.gov][11])

If you can chill feed gas (e.g., with waste heat-driven chillers or cold utility), you can condense sooner and move more of the pressure rise to the cheap liquid domain. (Several pipeline/capture integrations report reduced power this way.) ([ScienceDirect][9])

Bottom line

Cheapest per bar: liquid pumping (if you have/produce LCO₂).

Cheapest overall from low pressure: hybrid compress-condense-pump—it beats all-compressor trains on energy cost at the same discharge pressure.

Budgetary rule of thumb at $0.10/kWh:

All-gas to 110 bar: ~$11/ton electricity. ([IPCC][4])

Pump the last 40 bar as liquid: $0.10–$0.20/ton incremental. ([Pressbooks][3])

[1]: https://www.globalccsinstitute.com/archive/hub/publications/27421/co2-compression-report-final.pdf?utm_source=chatgpt.com CO2 COMPRESSION REPORT American Electric Power ...

[2]: https://www.cncdcryogenictank.com/cryogenic-liquid-pump/cryogenic-liquid-filling-pump/industrial-liquid-co2-gas-cryogenic-pumps.html?utm_source=chatgpt.com Industrial Liquid Co2 Gas Cryogenic Pumps 100bar ...

[3]: https://pressbooks.pub/thermo/chapter/chapter-4/?utm_source=chatgpt.com The First Law of Thermodynamics for Control Volumes

[4]: https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_chapter3-1.pdf?utm_source=chatgpt.com Capture of CO

[5]: https://www.globalccsinstitute.com/archive/hub/publications/119801/costs-co2-capture-post-demonstration-ccs-eu.pdf?utm_source=chatgpt.com The Costs of CO2 Capture

[6]: https://www.engineeringtoolbox.com/CO2-carbon-dioxide-properties-d_2017.html?utm_source=chatgpt.com Carbon Dioxide (CO₂) Properties & Characteristics

[7]: https://www.diva-portal.org/smash/get/diva2%3A1558492/FULLTEXT01.pdf?utm_source=chatgpt.com Multistage carbon dioxide compressor efficiency ...

[8]: https://www.giantpumps.com/pump_categories/co2-pumps/?utm_source=chatgpt.com CO2 Pumps

[9]: https://www.sciencedirect.com/science/article/abs/pii/S1750583621002012?utm_source=chatgpt.com Linking CO2 capture and pipeline transportation: sensitivity ...

[10]: https://www.mdpi.com/1996-1073/12/9/1603?utm_source=chatgpt.com Optimization of the Energy Consumption of a Carbon ...

[11]: https://netl.doe.gov/sites/default/files/2025-01/Carbon-Capture-Compendium-2024.pdf?utm_source=chatgpt.com CARBON CAPTURE PROGRAM R&D

Low-Cost Strategies for Pressurizing CO₂: Best Practices & Cost Benchmarks

Pressurizing CO₂ efficiently is critical for applications like pipeline transport, enhanced oil recovery, industrial usage, and geological sequestration. Given electricity at $0.10 per kilowatt-hour, here’s what the research shows about how to minimize cost while maintaining reliability and safety.

1. Key metrics & thermodynamic background

Dense phase / liquid CO₂: When CO₂ is compressed above its critical pressure (≈ 7.38 MPa or ~1070 psi) and held at suitable temperature, it behaves like a dense fluid—with much higher density than gas, but still compressible. Using dense phase or liquid conditions greatly reduces the work required for further pressure increases. ([The Department of Energy's Energy.gov][1])

Pump vs compressor work: Compressing gas requires many stages, inter-cooling, high mechanical complexity and energy. By contrast, once liquefied or in dense phase, pumping further pressure has a much lower specific energy cost (ΔP/ρ). Research shows replacing late gas compression stages with dense phase pumping can yield large energy savings. ([Cryogenic Society of America][2])

2. Comparison of compression pathways

| Pathway | Description | Energy & cost trade-offs |

| -• | -• | --• |

| All-gas compression | Gas from low pressure → high pressure using multi-stage compressors with inter-coolers etc. | Higher energy usage. Literature indicates that compressing CO₂ gas to ~110-150 bar using gas only can consume many tens to over one hundred kWh per ton of CO₂. Cost per ton at $0.10/kWh → several dollars per ton just for compression. ([POWER Magazine][3]) |

| Hybrid compression → dense-phase pumping | Compress gas to just below/around critical point, condense or liquefy, then pump dense fluid to final pressure. | Offers significant energy savings. A case study showed replacing last compressor stages with a centrifugal liquid pump in the dense phase yields over 50% savings in compression work for those stages. Overall, this hybrid method can reduce the compression energy by several percent of the total CO₂ processing cost. ([Cryogenic Society of America][2]) |

| Liquid CO₂ pumping | If CO₂ is already in liquid or dense state, use high-pressure pumps to raise pressure further rather than gas compressors. | Lowest incremental energy cost for additional pressure. Pumps are simpler, efficient, and cost per ton for these stages often drops to fractions of a $/ton of CO₂, when electricity cost is $0.10/kWh. References from dense phase injection and pipeline work show feasibility in this domain. ([Abset][4]) |

3. Typical energy and cost figures

Replacing final gas compression stages with dense fluid pumping (for example, going from ~40-80 bar upward) can reduce energy input for those stages by more than 50% in many designs. ([Cryogenic Society of America][2])

For large-scale CO₂ pipeline / transport systems, pumps designed for dense CO₂ can operate at pressures up to ~100 bar (≈1500 psi) with high throughput, holding CO₂ in dense or supercritical state. ([Abset][4])

The cost of compressing CO₂ gas to pipeline pressures (e.g. ~110-150 bar) is often in the tens to hundreds of kWh per ton of CO₂. If you assume compressing with all-gas, the electric energy cost could be $8-$15 per ton at $0.10/kWh, depending on pressure ratios, aftercooling, etc. Hybrid approaches reduce that substantially. (Exact numbers vary with inlet/outlet pressure, temperature, compressor efficiency.) ([POWER Magazine][3])

4. Best practices for minimizing cost

1. Operate above the CO₂ critical pressure where possible, so you can use dense phase fluid mechanics and pumping rather than high work gas compression. Aim for inlet feed to be as warm as safely possible but above critical pressure.

2. Use multi-stage compression with intercooling up to the condensation threshold. Then if feasible, condense or liquefy CO₂ before final pressure raise.

3. Choose high efficiency pumps specifically rated for dense CO₂ service: materials, seal design, inlet/outlet conditions must handle high pressure, temperature, and any CO₂ impurities. ([Abset][4])

4. Recover heat: Use waste heat or cooling systems to condense or cool CO₂ before pumping; cooling reduces compression energy and improves overall thermodynamic efficiency.

5. Minimize parasitic losses: design for low pressure drop in piping, avoid leaks, optimize electric drive efficiency.

5. Example cost estimate at $0.10/kWh

Here’s a rough calibration:

Suppose you need to pressurize CO₂ from near 1–2 bar (gas) to 150 bar.

All-gas compressor route might consume ~100 kWh per ton CO₂ → $10/ton for the electricity alone.

If you can do a hybrid route: compress gas to ~70 bar, condense/liquefy, then use a dense fluid pump for the final 80 bar, you might cut the electricity down to ~30-40 kWh per ton → $3-$4 per ton.

If CO₂ is already in liquid/dense phase at moderate pressure, then pumping to 150 bar might cost only a few kWh per ton → maybe $0.10-$1 per ton for that segment.

6. Conclusions

The lowest cost method is to push as much of the pressure rise as possible into the pumping of dense or liquid CO₂, because that has much lower work per unit mass than gas compression.

Hybrid architectures that combine gas-compression → condensation → dense phase pumping deliver strong cost savings, often halving or more the electricity expense compared to all-gas designs.

At $0.10/kWh electricity, the difference can be tens of dollars per ton of CO₂ avoided or transported—material in both industrial economics and carbon capture/sequestration project viability.

[1]: https://www.energy.gov/sites/default/files/2021-06/2019%20-%20Meeting%20the%20Dual%20Challenge%20Vol%20III%20Chapter%206.pdf?utm_source=chatgpt.com DUAL CHALLENGE

[2]: https://www.cryogenicsociety.org/index.php?category=industry-news&id=208%3Aanalyzing-transcritical-co2-compression-and-pumping-pathways&option=com_dailyplanetblog&view=entry&utm_source=chatgpt.com Analyzing Transcritical CO2 Compression and Pumping ...

[3]: https://www.powermag.com/capturing-co2-gas-compression-vs-liquefaction/?utm_source=chatgpt.com Capturing CO2: Gas Compression vs. Liquefaction

[4]: https://www.abset.com/vamp/wp-content/uploads/2014/07/fpd-17-ea4.pdf?utm_source=chatgpt.com Pumps for CO2 Capture, Transportation and Storage

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