Nitrogen, liquid

What it is

Unallocated foreground LCI of ASU-1 (500 t/d GOX), case design, derived from the flowsheet by cheme assess lca.

Reference product

1 kilogram of Nitrogen, liquid (liquid, 5.2 bar(a), -181 degC, 99.9202 % N2 (mole))

Chemical

nitrogen · grade lin

CAS

7727-37-9

Code

asu-1:asu-1-500-t-d-gox:product:LIN

Dataset

asu-1-500-t-d-gox version 0.1.0 · UUID 62b30292-ab30-52de-8732-1ab497ca8477

Activity UUID

not available (the library assigns none; use the code)

Database

cheme-as-code-atlas-preview-c3ab348 (version preview-c3ab348)

Process

Cryogenic air separation unit (500 t/d GOX)

Geography

GLO · background inputs with a site rule link at the user's site location (default DE)

Time period

2026 · valid until 2031

Technology

cryogenic double-column air separation, 500 t/d GOX, pumped liquid products, TSA front end

Boundary

gate-to-gate foreground of the plant with its construction

Production volume

175,224,000 kg/a (product:GOXP per hour x operation.hours_per_year (8400 h/a))

Classification

ISIC Rev.4 2011 (taxonomy/families.yaml (ISIC Rev.4) of the process's families)

CPC 34210 · HS 2804.30 (chemicals/chemicals.yaml (nitrogen))

System model

attributional, cut-off (docs/system-model.md, methodology 1.1.0)

Allocation

exergy, 2.9 % of the dataset to this product (rule physical-exergy, from mappings)

One cryogenic separation of air; GOX, GAN, LOX and LIN leave it in different thermodynamic states (compressed gas, gas at 9 bara, cold liquids), so exergy is the underlying physical relationship (hierarchy step 2a). Same method as the study (asu-1 DESIGN.md D-056), so the database and the study agree. Economic allocation would need prices (#46).

Rights

CC-BY-4.0: the ChemE-as-Code process library's own concept design (LICENSE-DATA)

Exchanges per 1 kilogram of Nitrogen, liquid

As exported: allocated and scaled to the reference product. Provenance: 11 assumed, 17 calculated. Pedigree scores (1 best, 5 worst): reliability, completeness, temporal correlation, geographical correlation, further technological correlation.

Elementary flows

No elementary flows are exported for this activity (pass-through emissions and free inputs are left out, see the caveats).

The streams are the plant's own flows: an amount here is allocated and per 1 kilogram of Nitrogen, liquid, so it differs from the stream's flow, and it can sum several streams.

Where these numbers come from: each exchange names its source above; the dataset is processes/asu-1/lca/dataset.yaml in library version c3ab348.

Left out under the system model

• end-of-life:steel-recycling: End-of-life steel scrap sent to recycling. Cut-off: the scrap leaves burden-free, the recycling belongs to the secondary steel that uses it, and no avoided-primary credit is given. ASU-1's dataset (end-of-life:steel-recycling) keeps the credit for the study's own question; the database leaves it out (database decision, process-library#52).
• end-of-life:aluminium-recycling: End-of-life aluminium scrap sent to recycling. Cut-off, as steel-recycling: no credit in the default build (process-library#52).

Used by

• Nitrogen, liquid market:nitrogen/lin:RER

How good it is

Review

Not reviewed: no LCI review record yet

Data quality

DQR 2.67 · PEF-style DQR 3

TeR 2 · GeR 5 · TiR 1 · P 3.98 · C 4 · weakest GeR · primary data 0 %

Mass and carbon closure

Assessed (lca/manifest.json balance, tolerance 5 %: design maturity screening (sourced screening))

• lci-carbon-origin: not-assessable
• lci-element-balance: not-assessable
• lci-mass-balance: closed

• element balance not assessable: no composition for consumable:molecular-sieve (no composition), consumable:lube-oil (no composition)
• carbon balance not assessable: no composition for consumable:molecular-sieve (no composition), consumable:lube-oil (no composition)

Change report

Not available: this build has no change report against an earlier release.

KPI benchmark positions

How to use it

Downloads

• cheme-as-code-atlas-preview-c3ab348.xlsx · bw2io ExcelImporter workbook (bw2io 0.9 Excel layout) · the whole database
  code asu-1:asu-1-500-t-d-gox:product:LIN
• cheme-as-code-atlas-preview-c3ab348-olca-jsonld.zip · openLCA JSON-LD (olca-schema) (2) · the whole database
  process 62b30292-ab30-52de-8732-1ab497ca8477 (processes/62b30292-ab30-52de-8732-1ab497ca8477.json) · the dataset's unallocated multi-output process; this product's allocation factor is in it
• cheme-as-code-atlas-preview-c3ab348-multifunctional.json · Brightway 2.5 multifunctional database (JSON, for the multifunctional package) (cheme-as-code/lci-multifunctional/v1) · the whole database
  code asu-1:asu-1-500-t-d-gox · the dataset unallocated, with all its products; this product is its desired_code
• cheme_as_code_lci-0.1.0-py3-none-any.whl · the installer

A file with this activity alone is not available: each file above is the whole database, and the line under it says how to find this activity there.

import bw2data as bd
from cheme_as_code_lci import install

bd.projects.set_current("my-project")   # holds your licensed background + biosphere3
install("cheme-as-code-atlas-preview-c3ab348.xlsx", background="ecoinvent-3.11-cutoff", location="DE")
activity = bd.get_activity(("cheme-as-code-atlas-preview-c3ab348", "asu-1:asu-1-500-t-d-gox:product:LIN"))

While any exchange of the database has no mapping, install() writes nothing and only lists the unlinked exchanges. So the last line finds no activity until the gaps are mapped: the download section gives the ways to use the database now.

How to cite

Nitrogen, liquid, from Cryogenic air separation unit (500 t/d GOX) (dataset asu-1-500-t-d-gox 0.1.0), ChemE-as-Code Process Atlas LCI database preview-c3ab348, activity asu-1:asu-1-500-t-d-gox:product:LIN. Cite the Process Atlas paper (in preparation, 2026), by Artur M. Schweidtmann and Jana M. Weber, and the ChemE-as-Code Process Atlas LCI database version preview-c3ab348.

DOI: none yet (the Process Atlas paper is in preparation)

@unpublished{schweidtmann_process_atlas,
  author = {Schweidtmann, Artur M. and Weber, Jana M.},
  title = {{Process Atlas: an open, git-native, reproducible library and life cycle inventory of chemical processes (working title)}},
  year = {2026},
  url = {https://atlas.cheme-as-code.org},
  note = {in preparation}
}

@unpublished{schweidtmann_cheme_as_code,
  author = {Schweidtmann, Artur M.},
  title = {{ChemE-as-Code: An Open-Source Platform for AI-Accelerated Chemical Process Engineering (working title)}},
  year = {2026},
  url = {https://cheme-as-code.org},
  note = {in preparation}
}