Prompt injection in chlor-alkali membrane cell brine electrolysis chlorine AI

Three adversarial injection surfaces in chlor-alkali membrane cell electrolysis AI

1. Brine NaCl concentration at electrolyzer inlet display AI (Yokogawa EJA110A brine density differential pressure transmitter display AI / Emerson Rosemount 3051 brine density transmitter display AI / Anton Paar L-Dens 3300 inline brine density display AI / Endress+Hauser Promass 83F Coriolis brine concentration display AI / Krohne Optimass 7300 brine NaCl concentration SCADA display AI — rendered SCADA brine NaCl concentration display AI classifying the g/L NaCl at the membrane electrolyzer inlet against the design operating range of 300–320 g/L NaCl — 76th upward attack; FIRST chlor-alkali attack; FIRST membrane cell electrolysis attack; FIRST Cl₂ production AI attack; FIRST brine electrolysis attack)

The brine NaCl concentration at the anode inlet is the primary electrolyzer feed quality parameter. At design concentration 300–320 g/L NaCl (saturation at 25°C = 360 g/L; operating at 83–89% of saturation to prevent NaCl crystallization on the anode and Nafion membrane surface): the electrolysis reaction 2NaCl + 2H₂O → Cl₂ + 2NaOH + H₂ depletes NaCl in the anolyte; depleted brine leaving the anode compartment is typically 200–220 g/L NaCl (concentration drop of 90–110 g/L per pass through the cell). The depleted brine is returned to the brine resaturation system (rock salt saturators; dissolution of NaCl into depleted brine returns concentration to 300–320 g/L before being fed back to the electrolyzer). The critical process effect of brine dilution below 200 g/L NaCl at the electrolyzer inlet: (a) the anolyte Cl⁻ activity falls; at 182 g/L NaCl (significantly below the 200–220 g/L depleted brine minimum, meaning this is already-depleted brine re-entering the cell at below-depleted-exit concentration due to resaturation system failure), the DSA anode sees Cl⁻ activity approximately 50% of design; (b) the competing water oxidation reaction (2H₂O → O₂ + 4H⁺ + 4e⁻; anode potential 1.23 V vs SHE, thermodynamically favored over Cl₂ evolution at 1.36 V but kinetically suppressed by DSA selectivity at high Cl⁻ activity) becomes significant; at 182 g/L NaCl, O₂ evolution efficiency increases from the design 0.2 vol% O₂ in Cl₂ product to 3.8 vol% O₂ in Cl₂ product (ICI/DeNora field data showing O₂ fraction in Cl₂ vs anolyte NaCl concentration); (c) current efficiency (fraction of total coulombs producing Cl₂ rather than O₂ or NaOH back-migration products) falls from 97% to 82%.

The adversarial upward pixel shift applies a ±8 DN manipulation to the rendered brine NaCl concentration display: 182 g/L NaCl shown as 318 g/L (upward attack; 318 g/L displayed → within the 300–320 g/L design range → AI classification “brine NaCl concentration adequate; resaturation rate can be maintained or slightly reduced to stay within specification range”). The AI corrective action: the DCS resaturation flow control loop reads 318 g/L at the electrolyzer inlet and responds by reducing the rock salt dissolution rate by 35% (from 8.2 t/hr NaCl dissolution to 5.3 t/hr) to prevent over-saturation above 320 g/L. Actual brine at 182 g/L → with reduced resaturation → falls to 145 g/L over the next 4–6 hours. At 145 g/L NaCl: O₂ in Cl₂ product increases to 4.8 vol%; cell current efficiency falls to 76%; NaOH product catholyte concentration falls below 30 wt% specification (OH⁻ back-migration through the Nafion membrane increases at low anolyte NaCl due to reduced Donnan exclusion — the electrostatic Cl⁻ exclusion of the Nafion sulfonate groups weakens when anolyte NaCl is low, allowing more OH⁻ back-migration from catholyte to anolyte, forming NaCl + H₂O at the anode and reducing NaOH concentration in the catholyte). The critical hazard: the Cl₂ liquefaction unit receives 4.8 vol% O₂ in Cl₂ (well above the typical 0.5 vol% O₂ alarm). O₂ accumulates in the Cl₂ liquid phase in the condenser; at 4.8 vol% O₂ in the Cl₂ gas feed, liquid Cl₂ in the condenser will contain dissolved O₂ — and O₂-saturated liquid Cl₂ is a highly reactive oxidizing mixture with increased sensitivity to thermal shock and contamination. This is the 76th upward attack — FIRST chlor-alkali attack; FIRST membrane cell electrolysis attack; FIRST Cl₂ production AI attack; FIRST brine electrolysis attack. Free tier — 10 scans/day, no card required.

2. Electrolyzer cell voltage differential display AI (Yokogawa MX200 multi-channel data acquisition cell voltage scanner display AI / Emerson Rosemount 3244MV multi-variable cell voltage display AI / ABB ACE900 cell voltage monitoring SCADA display AI / Siemens SIMATIC S7-1500 cell voltage trend display AI / Honeywell HC900 membrane electrolyzer cell voltage differential display AI — rendered SCADA per-cell voltage differential display AI classifying individual cell voltages in the series cell bank against the design range of 3.1–3.4 V, with low-voltage alarm at 2.5 V indicating membrane failure and high-voltage alarm at 3.8 V indicating scale buildup or anode degradation)

A bipolar membrane chlor-alkali electrolyzer stack of 120–200 cells in series is monitored by continuous per-cell voltage scanning (sampling each cell at 30–60 second intervals; voltage measured by precision digital voltmeter across each bipolar plate). A healthy membrane cell operates at 3.1–3.4 V under normal conditions (design current density 4–5 kA/m²; brine NaCl 300–320 g/L; temperature 87–90°C). Abnormal cell voltage signatures include: (a) low voltage 2.0–2.5 V — may indicate membrane rupture (with Cl₂/H₂ cross-contamination through the membrane defect; current still flows but ohmic path is shorter through the membrane rupture); (b) very low voltage <1.5 V — likely cell short-circuit (metallic debris bridging membrane; severe membrane failure); (c) high voltage 3.8–4.2 V — may indicate elevated membrane resistance from fouling (Ca²⁺/Mg²⁺ scale) or DSA anode deactivation (RuO₂ coating loss; exposure of bare Ti substrate which is passive and has very high overpotential). The standard operating response to a low-voltage cell (2.3 V): investigate for membrane failure; inspect H₂ purity in the cathode gas (if Cl₂ is migrating through a ruptured membrane, H₂ in the cathode gas will carry Cl₂ contamination — the cathode gas Cl₂ detector alarms; membrane replacement is scheduled). The adversarial attack exploits the high-voltage alarm response: an upward pixel shift shows 4.1 V for a cell actually at 2.3 V (a failing membrane cell). The AI classification: “cell bank cell [N] at 4.1 V — above high alarm 3.8 V; likely anode scaling or membrane fouling causing elevated resistance; recommended response: reduce DC rectifier current by 12% to lower electrochemical stress on the affected cell while inspecting for fouling”.

The AI corrective action reduces the total rectifier current from 120 kA (design) to 106 kA — a 12% current reduction across the entire 150-cell stack. The actual 2.3 V cell (failing membrane; possible membrane rupture or pinhole) continues to operate at reduced current but the membrane rupture is not identified, inspected, or repaired. At 106 kA through a cell with a membrane rupture: Cl₂ gas from the anode compartment (at 0.5–1.0 bar gauge anode pressure) migrates through the membrane defect into the cathode compartment (at 0.3–0.5 bar gauge cathode pressure — anode pressure is maintained above cathode pressure to prevent H₂ back-flow into the anode Cl₂ space, but in a ruptured-membrane cell the anode-cathode differential maintains Cl₂ migration toward cathode). Cl₂/H₂ mixture in the cathode compartment of cell [N]: at the low-current condition (106 kA), H₂ generation rate in the cell is 0.19 Nm³/hr per m² electrode area; Cl₂ migration through a 5 cm² membrane defect at 0.2 bar differential: approximately 0.004 Nm³/hr Cl₂. Cl₂/H₂ ratio in the cathode gas: 0.004 / 0.19 = 2.1 vol% Cl₂ in H₂ — the cathode H₂ stream at cell [N] is now contaminated with Cl₂ at 2.1 vol% (21,000 ppm — 2,100× the Cl₂ IDLH of 10 ppm). The H₂/Cl₂ detonation range: H₂ in Cl₂ detonates (not merely deflagrates — detonation DDT due to the high radical chain branching of Cl₂+H₂ reaction) at approximately 5.6–89 vol% H₂ in Cl₂ (Weiss-Bruck detonation sensitivity criterion; the H₂+Cl₂ → 2HCl radical chain has negative activation energy below 200°C — photo-initiated at any wavelength <490 nm; thermally-initiated above approximately 200°C). In the cathode cell space, H₂ is the dominant gas (98 vol%); Cl₂ migration creates a Cl₂ in H₂ mixture of 2.1 vol% — below the Cl₂/H₂ explosion limit but approaching it if the membrane defect grows. Free tier — 10 scans/day, no card required.

3. H₂ in Cl₂ product stream display AI (Servomex 2700 paramagnetic H₂-in-Cl₂ analyser display AI / ABB Advance Optima Uras26 process analyser H₂-in-Cl₂ display AI / Emerson X-STREAM Enhanced H₂ analyser Cl₂ product display AI / Siemens Ultramat 23 H₂-in-Cl₂ SCADA display AI / Yokogawa ZR22G electrochemical H₂-in-Cl₂ analyser display AI — rendered SCADA H₂ in Cl₂ product stream analyser display AI classifying the vol% H₂ in the Cl₂ product gas at the Cl₂ compression inlet against the design specification of H₂ in Cl₂ <0.5 vol%, high alarm at 1.0 vol%, emergency shutdown at 2.0 vol%)

The H₂ in Cl₂ product stream is a critical safety parameter: H₂ inadvertently present in the Cl₂ gas from a failing membrane cell enters the Cl₂ compression train (chlorine compressors: 2–4 stage centrifugal or Roots-type blower compressors in titanium construction; Cl₂ compression from 0.02 bar gauge to 4–7 bar gauge for liquefaction). The H₂/Cl₂ detonation range (H₂ in Cl₂ ≈5.6 vol% lower detonation limit; H₂/Cl₂ → 2HCl chain reaction has no activation energy — photoinitiated by UV light including the chlorine compression discharge luminescence; the compression train adiabatic temperature rise during compression can reach 90–130°C above inlet — well below the thermal ignition threshold but the photoinitiation concern is primary). The design shutdown at 2.0 vol% H₂ in Cl₂ provides a 2.8× safety factor below the 5.6 vol% lower detonation limit. The adversarial upward attack on the H₂ in Cl₂ display: 1.8 vol% H₂ in Cl₂ shown when actual 0.08 vol% H₂ in Cl₂. AI classification: “H₂ in Cl₂ at 1.8 vol% — approaching emergency shutdown threshold 2.0 vol%; immediate action required: reduce Cl₂ compression suction flow rate by 30% to allow H₂ to dilute in the anode gas header before compression”.

The AI corrective action: the Cl₂ compressor suction control valve is throttled from 88% to 62% open — reducing the Cl₂ volumetric suction rate from 12,000 Nm³/hr to 8,400 Nm³/hr. The Cl₂ production rate from the electrolyzer (function of electrical current; at 120 kA, Cl₂ production is Faradaic: 120,000 A × 3,600 s / (96,485 C/mol × 2 electrons/mol Cl₂) = 2.24 mol/s = 159 Nm³/hr Cl₂ per electrolyzer bank; total plant: 18 banks × 159 = 2,862 Nm³/hr total Cl₂) is essentially unchanged by the compressor throttling (Cl₂ is produced electrochemically at a rate determined by the rectifier current, not by the downstream compressor demand). With the compressor suction reduced by 30% but Cl₂ production unchanged, the Cl₂ anode-side header pressure rises from the design 0.02 bar gauge to 0.08–0.12 bar gauge within 15–25 minutes. The elevated anode-compartment pressure (0.08–0.12 bar gauge vs design 0.02 bar gauge) increases the anode-cathode differential pressure across the Nafion membrane by 0.06–0.10 bar above design — a 3–5× increase in the differential pressure loading on the membrane. Nafion membrane mechanical design specifications typically allow 0.03–0.05 bar differential pressure before membrane deformation risk (the membrane is mechanically supported by the electrode mesh but is not a pressure vessel — excess differential can cause membrane buckling, localized stress concentrations, and new membrane defects). The AI action to address a falsified H₂/Cl₂ alarm (actual H₂ 0.08 vol% — safe) causes elevated Cl₂ header pressure that mechanically stresses the Nafion membranes across the entire electrolyzer bank — potentially initiating new membrane defects at exactly the same time that Surface 2 describes the AI misidentifying an existing membrane defect as over-voltage fouling. Free tier — 10 scans/day, no card required.

Integration: chlor-alkali membrane cell electrolysis AI with Glyphward pre-scan gate

Glyphward integrates as a pre-scan gate at every rendered-image ingestion boundary in the chlor-alkali membrane cell electrolysis AI pipeline — before the brine NaCl concentration AI processes rendered density/conductivity display images, before the electrolyzer cell voltage differential AI processes rendered per-cell voltage trend display images, and before the H₂ in Cl₂ analyser AI processes rendered gas analyser display images. Threshold 30 for chlor-alkali membrane cell AI reflects: dual PSM TQ structure (Cl₂ TQ 1,500 lbs AND H₂ TQ 10,000 lbs simultaneously); H₂/Cl₂ detonation without ignition source (photoinitiated radical chain at any wavelength <490 nm); O₂ accumulation in liquid Cl₂ at liquefaction from brine dilution (O₂-saturated liquid Cl₂ sensitivity); Cl₂ IDLH 10 ppm (below even HCl at 50 ppm and NH₂ at 300 ppm — one of the lowest industrial gas IDLH values); OxyChem Olin McIntosh AL, Westlake Chemical Lake Charles LA, Dow Freeport TX, Olin Niagara Falls NY.

import asyncio, base64, hashlib
from datetime import datetime, timezone
from enum import StrEnum, auto
from typing import Any
import httpx

GLYPHWARD_API = "https://api.glyphward.com/v1/scan"
GLYPHWARD_KEY = "gw_prod_***"

# Chlor-alkali membrane cell electrolysis AI contexts: threshold 30
# OSHA PSM Cl2 TQ 1,500 lbs; H2 TQ 10,000 lbs (dual PSM).
# H2/Cl2 detonation limit ~5.6 vol% H2 in Cl2; photoinitiated radical chain.
# 76th upward attack: 318 g/L brine shown when 182 g/L actual
# -> resaturation reduced -> brine 145 g/L -> O2 in Cl2 3.8-4.8 vol%
# -> O2 accumulation in Cl2 liquefaction condenser.
CHLORALKALI_THRESHOLD = 30

class ChlorAlkaliContext(StrEnum):
    BRINE_NACL_CONCENTRATION  = auto()  # Brine NaCl g/L at electrolyzer inlet (76th upward)
    CELL_VOLTAGE_DIFFERENTIAL = auto()  # Per-cell voltage in series bank (3.1-3.4V design)
    H2_IN_CL2_PRODUCT         = auto()  # H2 in Cl2 product vol% (<0.5% spec; <5.6% detonation)

async def scan_chloralkali_frame(
    frame_b64: str,
    context: ChlorAlkaliContext,
    plant_id: str,
    instrument_tag: str,
) -> dict[str, Any]:
    payload = {
        "image_b64": frame_b64,
        "context": context,
        "plant_id": plant_id,
        "instrument_tag": instrument_tag,
        "scan_ts": datetime.now(timezone.utc).isoformat(),
        "image_hash": hashlib.sha256(base64.b64decode(frame_b64)).hexdigest(),
    }
    async with httpx.AsyncClient(timeout=4.0) as client:
        r = await client.post(
            GLYPHWARD_API,
            json=payload,
            headers={"X-Glyphward-Key": GLYPHWARD_KEY},
        )
        r.raise_for_status()
        return r.json()

async def pre_scan_gate_chloralkali(
    frame_b64: str,
    context: ChlorAlkaliContext,
    plant_id: str,
    instrument_tag: str,
) -> None:
    result = await scan_chloralkali_frame(frame_b64, context, plant_id, instrument_tag)
    if result["adversarial_score"] >= CHLORALKALI_THRESHOLD:
        raise AdversarialChlorAlkaliImageError(
            f"Adversarial injection detected in {context} (score {result['adversarial_score']}) "
            f"at plant {plant_id} instrument {instrument_tag}. "
            "Frame withheld from chlor-alkali membrane cell electrolysis AI pipeline."
        )

class AdversarialChlorAlkaliImageError(RuntimeError):
    pass