14 02 2023

CO₂ Specifications for Aramis transport infrastructure

Aramis aims to realizing a transport infrastructure allowing the industrial sector to transport CO and store it in depleted gas fields under the North Sea. Aramis has established a specification for the CO to be fed into the envisaged transport infrastructure. This specification aims to ensure the non-corrosivity of the CO mixture under normal, transient and upset conditions. Maximum alignment has been pursued with specifications for existing and other planned CCS infrastructure. In the overview you can find all specific requirements per class, component, constraint and unit and other information. At the end, you also find a PDF with the specifications for easy download (see green box).

Specification for CO₂ supplied to Aramis via:

Class Component Constraint Unit Ships Pipeline infrastructure
CO₂ larger than mol% balance 95
H₂O less than ppmmol 30 70⁽¹⁾
inerts N₂  less than mol% - 2.4
inerts O₂ less than ppmmol 10 40
inerts H₂ less than ppmmol 500 7500
inerts Ar less than mol% - 0.4
inerts CH₄ less than mol% - 1
inerts CO less than ppmmol 1200 750
inerts O₂+N₂+H₂+Ar+CH₄+CO sum less than ppmmol 2000 40000
NOₓ sum less than ppmmol 1.5 2.5⁽⁴⁾
sulphur SOₓ sum less than ppmmol 10 -
sulphur H₂S  less than ppmmol 5 5
sulphur CarbonylSulphide less than ppmmol - -⁽¹⁾
sulphur DimethylSulphide less than ppmmol - -⁽¹⁾
sulphur H₂S + COS + SOₓ + DMS sum less than ppmmol - 20
Volatile organic components Amine less than ppmmol 10 1
Volatile organic components Formaldehyde less than ppmmol 20 -
Volatile organic components Acetaldehyde less than ppmmol 20 -⁽¹⁾
Volatile organic components Aldehydes sum less than ppmmol - 10
Volatile organic components carbolylic acids & amides sum less than ppmmol - 1
Volatile organic components phosphorus-containing compounds sum less than ppmmol - 1
Volatile organic components NH₃ less than ppmmol 10 3
Volatile organic components Ethylene (C₂H₄) sum less than ppmmol - -⁽¹⁾
Volatile organic components H-Cyanide (HCN) less than ppmmol - 2
Volatile organic components Total volatile organic compounds (excl. MeOH, EtOH, aldehydes) sum less than ppmmol 10 10
Volatile organic components Methanol less than ppmmol 40 620
Volatile organic components Ethanol less than ppmmol 20 20
Heavies glycols (TEG) sum less than - Follow dew-point specification
Heavies C₂₊ (aliphatic hydrocarbons)  sum less than ppmmol - 1200
Heavies Aromatic Hydrocarbons sum less than ppmmol - 0.1
Metals Hg less than ppbmol 30 -
Metals Cadmium + Thalium  sum less than ppbmol 30 -
Dew-point Dew point (any liquid phase) sum less than °C (@ 20 bar) - -10 ⁽²⁾
Solids Full removal cut-off diameter Less than micron 1⁽³⁾ 1⁽³⁾

Notes to the table

  1. There are some specific limits when transporting via OCAP infrastructure that can be obtained from OCAP B.V. (www.ocap.nl)
  2. Measured or predicted using CPA equation of state.
  3. This is the entry solids / dust specification for the envisaged Aramis stores. In order to achieve this Aramis will request Aramis emitters to install dust removal facilities with a cut-off diameter of 10 micron as a minimum. Furthermore, Aramis is planning to locate filters with cut-off diameter of 1 micron at optimal locations at the envisaged compressor and terminal stations.
  4. Specification more stringent than Porthos CO2 specification v 3.1 at 5 ppmm The limit is set based on testing similar to those described in section A.4 in ISO TR 27921 at seabed conditions.

A number of impurities are included in the overview without a specific limit to their content. Emitters agree to inform Aramis in case these components are expected in the CO2 product at levels above 1 ppmmol. Aramis will then conduct a risk assessment study to understand the maximum amount that can be tolerated.

If the aforementioned CO2 stream, includes components that are not included in the Aramis CO2 specification and that can adversely affect Aramis, its personnel or the Aramis Transport System (e.g. as a result of liquid formation, corrosion or toxicity (HSE)), then Aramis shall in relation to each such component in consultation with customer, but at Aramis’ sole discretion establish an upper concentration limit. The aggregate of these components and related concentration limits, as established from time to time shall constitute the CO2 specification.

The risk assessment for impurities in a CO2 collection hub system and in particular the interaction of impurities from different sources is an ongoing field of research. A good summary of today’s understanding is the 2020 issue of ISO TR 27921. Evolving insights may result in a re-visit of the risks associated with a particular impurity or combination of impurities. Aramis plans to actively manage these risks and hereby reserves the right to adjust the specification, if the existing level will adversely affect Aramis, people working on the project, or the envisaged Aramis Transport System.