Sodium hydroxide, Caustic soda 50 wt-% to storage

What it is

Unallocated foreground LCI of Chlor-alkali membrane-cell plant (100 kt/a Cl2, 50 wt-% NaOH, H2), case design, derived from the flowsheet by cheme assess lca.

Reference product

1 kilogram of Sodium hydroxide, Caustic soda 50 wt-% to storage (2.5 bar(a), 50 degC, 50 % NaOH (mass))

Chemical

sodium-hydroxide

CAS

1310-73-2

Code

chlor-alkali-1:chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2:product:NAOH

Dataset

chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2 version 0.1.0 · UUID 1de76be9-296d-5436-972d-1173af6562c0

Activity UUID

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

Database

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

Process

Chlor-alkali by membrane-cell electrolysis (100 kt/a Cl2, 50 wt-% caustic soda, hydrogen)

Geography

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

Time period

2026 · valid until 2031

Technology

bipolar membrane-cell NaCl electrolysis, 100 kt/a Cl2, rock salt with brine recirculation, 3.0 V at 6.0 kA/m2, double-effect caustic evaporation to 50 wt-% · level current

Boundary

gate-to-gate foreground of the plant

Production volume

100,818,480 kg/a (product:CL2 per hour x operation.hours_per_year (8000 h/a))

Classification

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

System model

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

Allocation

shares, 52.1 % of the dataset to this product (rule deviation, from study)

Hierarchy step 3 (WBCSD price ratio) cannot be applied: no sourced prices of Cl2, NaOH and H2 are recorded for this concept design. Mass of the contained products is used instead, as shares, because core's mass method weighs the product streams including the water of the 50 wt-% caustic and of the wet hydrogen. To be revisited when prices are sourced (D-013).

Rights

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

Exchanges per 1 kilogram of Sodium hydroxide, Caustic soda 50 wt-% to storage

As exported: allocated and scaled to the reference product. Provenance: 14 assumed. Pedigree scores (1 best, 5 worst): reliability, completeness, temporal correlation, geographical correlation, further technological correlation.

Elementary flows

The streams are the plant's own flows: an amount here is allocated and per 1 kilogram of Sodium hydroxide, Caustic soda 50 wt-% to storage, 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/chlor-alkali-1/lca/dataset.yaml in library version c3ab348.

Left out under the system model

• product:SPENT: Spent sulfuric acid (chlor-alkali-1, about 75 wt-% from chlorine drying) sent off site for re-use or reconcentration. Cut-off at the point of recycling: it leaves burden-free, the user or reconcentrator carries the treatment, and no avoided-acid credit is given.

Used by

• Acetone product acetone-1:phenol-and-acetone-from-cumene-cumene-hydroperoxide-route:product:ACETONE
• Phenol product acetone-1:phenol-and-acetone-from-cumene-cumene-hydroperoxide-route:product:PHENOL
• Aluminium oxide, Smelter-grade alumina to storage alumina-1:alumina-by-the-bayer-process-3000-t-d-smelter-grade-alumina:product:ALU
• Fatty-acid layer to the biodiesel plant glycerol-1:crude-glycerol-refining-to-usp-glycerol-10-000-t-a-99.7-wt:product:FAL
• Refined glycerol USP 99.7 wt% to storage glycerol-1:crude-glycerol-refining-to-usp-glycerol-10-000-t-a-99.7-wt:product:GLYC
• Iodine flakes (99.8 wt% I2) to packing iodine-1:iodine-from-natural-brine-by-chlorine-oxidation-air-blowing-out-and-so2-absorption-1000-t-a:product:IODINE
• Bleached kraft pulp, Bleached softwood kraft market pulp, 90 % dry (bales) kraft-pulp-1:bleached-softwood-kraft-pulp-with-chemical-recovery-1000-adt-d-market-pulp:product:PULP
• N-Bromosuccinimide crystals to packing n-bromosuccinimide-1:n-bromosuccinimide-by-semi-batch-bromination-of-succinimide-in-aqueous-naoh-500-t-a:product:NBS
• Liquid phosgene to the captive consumer phosgene-1:phosgene-from-co-and-chlorine-over-activated-carbon-17.3-t-h-liquid-phosgene-captive:product:PHOSGENE
• Phosphorus oxychloride (phosphoryl chloride), Phosphorus oxychloride (distilled) to storage phosphorus-oxychloride-1:phosphorus-oxychloride-from-white-phosphorus-chlorine-and-oxygen-4.0-t-h-pocl3:product:POCL3
• Solid sodium cyanide (98 wt%) to packing sodium-cyanide-1:solid-sodium-cyanide-from-andrussow-hcn-6.25-t-h-nacn:product:NACN
• Thionyl chloride to storage thionyl-chloride-1:thionyl-chloride-from-sulfur-chlorine-and-so2-over-activated-carbon-3.75-t-h:product:SOCL2

How good it is

Review

Not reviewed: no LCI review record yet

Data quality

DQR 2.33 · PEF-style DQR 2.75

TeR 3 · GeR 3 · TiR 1 · P 4 · C 4 · weakest TeR · primary data 0 %

Mass and carbon closure

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

• lci-carbon-origin: closed
• lci-element-balance: closed
• lci-mass-balance: closed

Change report

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

KPI benchmark positions

Not available: no benchmarked KPI for this dataset.

How to use it

Downloads

• cheme-as-code-atlas-preview-c3ab348.xlsx · bw2io ExcelImporter workbook (bw2io 0.9 Excel layout) · the whole database
  code chlor-alkali-1:chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2:product:NAOH
• cheme-as-code-atlas-preview-c3ab348-olca-jsonld.zip · openLCA JSON-LD (olca-schema) (2) · the whole database
  process 1de76be9-296d-5436-972d-1173af6562c0 (processes/1de76be9-296d-5436-972d-1173af6562c0.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 chlor-alkali-1:chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2 · 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", "chlor-alkali-1:chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2:product:NAOH"))

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

Sodium hydroxide, Caustic soda 50 wt-% to storage, from Chlor-alkali by membrane-cell electrolysis (100 kt/a Cl2, 50 wt-% caustic soda, hydrogen) (dataset chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2 0.1.0), ChemE-as-Code Process Atlas LCI database preview-c3ab348, activity chlor-alkali-1:chlor-alkali-membrane-cell-plant-100-kt-a-cl2-50-wt--naoh-h2:product:NAOH. 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}
}