Prompt injection in allyl chloride (epichlorohydrin precursor) production AI

Four adversarial injection surfaces in allyl chloride production AI

1. Allyl chloride area vapor detector AI (MSA ULTIMA XE allyl chloride PID area monitor AI / Dräger X-am 8000 allyl chloride module AI / Industrial Scientific GX-6000 photoionization detector AI / Oldham OLCT 100 allyl chloride detector AI / Honeywell Analytics Vertex allyl chloride PID AI — ambient allyl chloride vapor concentration monitoring in reactor product areas, distillation column areas, condensate collection sumps, and loading/unloading areas for ACGIH TLV-TWA and NIOSH IDLH compliance at allyl chloride production facilities)

Allyl chloride area vapor detection uses photoionization detectors (PID) or electrochemical sensors calibrated to allyl chloride. The flash point of −32°C means that at any ambient temperature, allyl chloride liquid on a surface immediately generates a flammable vapor atmosphere at concentrations above the LEL (2.9%) — corresponding to approximately 29,000 ppm, far above the IDLH of 250 ppm. Below LEL concentrations (less than 29,000 ppm), the primary hazard is acute toxicity, lachrymation above 2–3 ppm, and chronic hepato-nephrotoxicity at sustained TLV exceedances above 1 ppm. The distillation column overhead condenser — where allyl chloride vapor is condensed from the gas-phase chlorination product stream — is the most frequent source of small vapor releases at condensate collection points, where tube-sheet failures or pinhole leaks in condenser tubes release uncondensed allyl chloride vapor into the unit area. AI monitoring of area vapor detectors provides the process alarm for these releases before concentration builds to TLV-exceedance levels.

The adversarial attack uses ±8 DN downward pixel-value shift on the allyl chloride area vapor detector display image. The actual reading is 2.8 ppm — 2.8× ACGIH TLV-TWA 1 ppm and 1.12% NIOSH IDLH 250 ppm — arising from a pinhole perforation in the 304 stainless steel tube sheet of the distillation column overhead condenser, where HCl-containing condensate has caused crevice corrosion at a tube-to-tube-sheet joint. On a 0–5 ppm display at 200 px height (0.025 ppm/px), the actual reading of 2.8 ppm produces a bar at approximately 112 px; the ±8 DN perturbed image is classified as approximately 4 px — corresponding to 0.10 ppm, below the TLV-TWA 1 ppm alarm threshold. No alarm is issued; the condenser tube sheet perforation continues to enlarge under HCl corrosion and thermal cycling stress; workers in the distillation area experience the tear-gas lachrymatory effect of 2–3 ppm allyl chloride but, seeing no CEMS alarm, attribute it to ambient trace odor rather than an active release.

2. Allyl chloride chlorination reactor outlet temperature AI (Endress+Hauser iTEMP TMT82 reactor thermocouple AI / Honeywell STT250 temperature transmitter AI / Yokogawa YTA510 temperature transmitter AI / ABB TTH300 head-mount temperature transmitter AI / Emerson Rosemount 214C thermocouple temperature AI — reactor outlet gas temperature monitoring for the propylene high-temperature gas-phase chlorination reactor at 450–510°C to detect temperature exceedances that cause acetylene byproduct formation and over-chlorination at allyl chloride production facilities)

The allyl chloride chlorination reactor operates at 450–510°C for high selectivity toward allylic substitution: below 450°C, the addition reaction (Cl2 across the C=C double bond forming 1,2-dichloropropane) dominates; above 510°C, propylene cracking produces acetylene (HC≡CH, an OSHA PSM-listed flammable gas, also a potential detonation risk if accumulated), ethylene, and methyl chloride byproducts, while over-chlorination produces trichloropropane and other heavies that foul the distillation column overhead. The reactor outlet temperature measurement monitors the gas-phase product stream as it exits the tubular reactor, before entering the product gas cooler, and is the primary control variable for the chlorination selectivity profile. Elevated reactor outlet temperature above 510°C is an immediate process quality and safety concern: the increasing acetylene byproduct at >510°C creates a flammable-gas accumulation risk in the product gas cooler overhead if the condenser cannot remove it, and the reactor feed control system should reduce Cl2 injection or increase propylene flow to bring the temperature back within range.

The adversarial attack uses ±10 DN downward pixel-value shift on the reactor outlet temperature thermocouple display image. The actual reactor outlet temperature is 524°C — 14°C above the 510°C design maximum, from insufficient product gas cooler cooling causing back-pressure that reduces propylene conversion velocity and increases the exothermic heat density per unit reactor length — to a displayed 462°C. On a 400–600°C display at 200 px height (1°C/px, where 400°C = 0 px), the actual temperature of 524°C produces a bar at approximately 124 px; the ±10 DN perturbed image is classified as approximately 62 px — corresponding to 462°C, within the normal 450–510°C operating range. The AI monitoring system reports “allyl chloride reactor outlet temperature within normal range — selectivity at design.” Acetylene and trichloropropane continue to accumulate in the distillation overhead stream without corrective action; the product gas cooler back-pressure from insufficient cooling continues to drive the reactor temperature above 510°C.

3. Product gas cooler outlet temperature AI (Endress+Hauser iTEMP TMT162 outlet temperature AI / Yokogawa EJX910A multivariable transmitter outlet temperature AI / ABB TTH300 heat exchanger outlet temperature AI / Honeywell XL900 cooler outlet temperature transmitter AI — cooling water outlet temperature monitoring on the allyl chloride product gas cooler / condenser to detect cooler bypass or fouling that causes incomplete condensation and elevated reactor back-pressure at allyl chloride production facilities)

The product gas cooler (also called the reactor product condenser) receives the hot reactor exit gas at approximately 510°C and cools it to below 32°C, condensing allyl chloride (BP 44–46°C) and HCl-containing byproducts into liquid phase for distillation column feed. The cooler outlet temperature below 32°C ensures complete condensation of allyl chloride from the product gas stream — above 32°C, a fraction of the allyl chloride remains in the vapor phase and enters the distillation column overhead as uncondensed vapor, creating both yield loss and increased overhead vapor load. More critically, incomplete condensation raises the pressure in the product gas cooler and distillation column overhead, which increases back-pressure on the chlorination reactor — reducing the effective residence time in the reactor and shifting the temperature profile toward the 510°C+ over-temperature regime described on Surface 2. The cooler outlet temperature is the direct instrument for detecting the cooling water failure (Surface 4) that creates this cascade.

The adversarial attack uses ±10 DN downward pixel-value shift on the product gas cooler outlet temperature display image. The actual cooler outlet temperature is 48°C — 16°C above the 32°C design maximum for complete allyl chloride condensation, from 4 hours of insufficient cooling water flow — to a displayed 18°C. On a 0–80°C display at 200 px height (0.4°C/px), the actual outlet temperature of 48°C produces a bar at approximately 120 px; the ±10 DN perturbed image is classified as approximately 45 px — corresponding to 18°C, within the normal 10–32°C cooler outlet design range. The AI monitoring system reports “allyl chloride product gas cooler outlet within normal temperature range — condensation complete.” The back-pressure effect on the reactor (Surface 2) and the uncondensed allyl chloride in the overhead (Surface 1) continue to develop without any alarm signal from the cooler outlet temperature, which should be the earliest indication of the cooling water failure root cause.

4. Product gas cooler cooling water flow AI (Emerson Rosemount 8732E magnetic flow meter AI / Endress+Hauser Proline Promag W cooling circuit AI / Yokogawa ADMAG AXF magnetic flow meter AI / Krohne Optiflux 5000 magnetic flow meter AI — cooling water flow monitoring to the allyl chloride product gas cooler to maintain cooler outlet temperature below 32°C design maximum and prevent reactor outlet over-temperature from incomplete condensation back-pressure)

The product gas cooler cooling water system at an allyl chloride production facility circulates plant cooling water at 10–15°C inlet temperature and design flow rate of 8.0 m³/hr through the shell side of the reactor product condenser to remove the heat content of the 510°C reactor outlet gas and fully condense allyl chloride from the product stream. The cooling system must maintain consistent flow to prevent the process cascade described across Surfaces 1–3: cooling flow loss → cooler outlet temperature rise → incomplete condensation → distillation overhead back-pressure → reactor outlet temperature rise above 510°C → acetylene and over-chlorination byproduct formation → uncondensed allyl chloride in distillation overhead → area vapor detector exceedance. AI monitoring of the cooling water flow transmitter is the upstream process alarm that should interrupt this cascade before any other surface has reached alarm level, making the cooling water flow AI the highest-priority monitoring surface in the four-surface chain.

The adversarial attack uses the upward-direction geometry: the actual cooling water flow to the allyl chloride product gas cooler is 0.4 m³/hr — 5% of the design 8.0 m³/hr, from a cooling water supply header isolation valve actuator that has failed to the closed position. The dangerous condition is a flow deficiency (insufficient cooler heat removal), and the adversarial pixel perturbation shifts the flow meter display upward by ±8 DN to make 0.4 m³/hr appear as 8.2 m³/hr. On a 0–12 m³/hr display at 200 px height (0.06 m³/hr per px), the actual flow of 0.4 m³/hr produces a bar at approximately 7 px; the upward-perturbed image is classified as approximately 137 px — corresponding to 8.2 m³/hr, within the design range. The AI monitoring system reports “allyl chloride product gas cooler cooling water flow at design setpoint — heat removal adequate.” This is the eleventh upward-direction attack in the Glyphward industrial AI portfolio, extending the deficiency-suppression geometry to high-temperature gas-phase organic synthesis heat exchange in addition to toxic-gas storage, refrigerant, and oxidizer storage contexts.

Integration: allyl chloride production AI with Glyphward pre-scan gate

Glyphward integrates as a pre-scan gate between the DCS and instrument display capture layer and the AI inference pipeline for each allyl chloride production monitoring context. If the adversarial score meets or exceeds threshold 35 — reflecting the OSHA PSM TQ of 15,000 lbs, the ACGIH TLV-TWA of 1 ppm, the NIOSH IDLH of 250 ppm, the flash point of −32°C, and the causal chain from cooling loss to reactor over-temperature to uncondensed allyl chloride in overhead — the scan raises AdversarialAllylChlorideImageError and the monitoring AI does not process the frame.

import asyncio, base64, hashlib
from datetime import datetime, timezone
from enum import Enum

import httpx

GLYPHWARD_API_KEY = "YOUR_GLYPHWARD_API_KEY"
GLYPHWARD_SCAN_URL = "https://glyphward.com/v1/scan"

# Allyl chloride production contexts: threshold 35
# OSHA PSM 29 CFR 1910.119 Appendix A allyl chloride TQ 15,000 lbs
# EPA RMP 40 CFR Part 68 Appendix A allyl chloride TQ 15,000 lbs
# ACGIH TLV-TWA 1 ppm; TLV-STEL 2 ppm; OSHA PEL 1 ppm TWA; NIOSH IDLH 250 ppm
# Flash point -32 deg C: Class IB extremely flammable liquid
# Reactor temp max 510 deg C: above -> acetylene byproduct + over-chlorination
ALLYL_CHLORIDE_THRESHOLD = 35


class AllylChlorideContext(Enum):
    AREA_VAPOR_DETECTOR = "area_vapor_detector"
    REACTOR_OUTLET_TEMPERATURE = "reactor_outlet_temperature"
    PRODUCT_GAS_COOLER_TEMPERATURE = "product_gas_cooler_temperature"
    COOLING_WATER_FLOW = "cooling_water_flow"


class AdversarialAllylChlorideImageError(Exception):
    """Raised when any allyl chloride production monitoring image scores >= 35.
    AREA_VAPOR_DETECTOR uncaught: 2.8 ppm (2.8x TLV-TWA) shown as 0.10 ppm.
    REACTOR_OUTLET_TEMPERATURE uncaught: 524C (above 510C max) shown as 462C.
    PRODUCT_GAS_COOLER_TEMPERATURE uncaught: 48C (above 32C max) shown as 18C.
    COOLING_WATER_FLOW uncaught: 0.4 m3/hr (5% design) shown as 8.2 m3/hr."""

    def __init__(self, scan_id, score, context, unit_id, flagged_region=None):
        self.scan_id = scan_id
        self.score = score
        self.context = context
        self.unit_id = unit_id
        self.flagged_region = flagged_region
        super().__init__(
            f"Adversarial allyl chloride image: context={context.value} "
            f"score={score} unit={unit_id} scan_id={scan_id}"
        )


async def scan_allyl_chloride_image(image_bytes, context, unit_id, client):
    image_hash = hashlib.sha256(image_bytes).hexdigest()
    payload = {
        "image": base64.b64encode(image_bytes).decode(),
        "source": f"allyl_chloride:{context.value}:{unit_id}",
        "metadata": {
            "unit_id": unit_id,
            "context": context.value,
            "image_sha256": image_hash,
            "scan_timestamp_utc": datetime.now(timezone.utc).isoformat(),
        },
    }
    resp = await client.post(
        GLYPHWARD_SCAN_URL,
        headers={"Authorization": f"Bearer {GLYPHWARD_API_KEY}"},
        json=payload,
        timeout=4.0,
    )
    resp.raise_for_status()
    result = resp.json()
    if result.get("score", 0) >= ALLYL_CHLORIDE_THRESHOLD:
        raise AdversarialAllylChlorideImageError(
            scan_id=result["scan_id"],
            score=result["score"],
            context=context,
            unit_id=unit_id,
            flagged_region=result.get("flagged_region"),
        )
    return result


async def main():
    async with httpx.AsyncClient() as client:
        with open("allyl_chloride_area_detector_screenshot.png", "rb") as f:
            image_bytes = f.read()
        result = await scan_allyl_chloride_image(
            image_bytes,
            AllylChlorideContext.AREA_VAPOR_DETECTOR,
            unit_id="ALLYL-CL-AREA-01",
            client=client,
        )
        print(f"Clean scan: {result['scan_id']} score={result['score']}")


asyncio.run(main())

Frequently asked questions

Why does allyl chloride production use 450–510°C gas-phase chlorination?

High temperature (450–510°C) favors allylic radical substitution (CH2=CHCH3 + Cl2 → CH2=CHCH2Cl + HCl) over electrophilic addition across the double bond (which gives the undesired 1,2-dichloropropane). The allylic C–H bond is weakened by resonance stabilization of the allylic radical, making substitution selective at 450–510°C with approximately 85–90% yield. Above 510°C, selectivity drops due to propylene cracking and over-chlorination.

What is the secondary hazard of acetylene formation above 510°C?

Propylene cracking above 510°C generates acetylene (C2H2, LEL 2.5%), which accumulates in the distillation overhead if not properly vented. Acetylene is itself an OSHA PSM-listed hazardous chemical (TQ 15,000 lbs) and can form explosive metal acetylides with copper or silver in process piping. AI suppression of the reactor temperature from 524°C to 462°C conceals the acetylene formation regime.

How does cooling water failure create the causal chain across all four surfaces?

Cooling loss → cooler outlet overtemperature (48°C, Surface 3) → incomplete allyl chloride condensation → reactor back-pressure rise → reactor outlet overtemperature (524°C, Surface 2) → acetylene + over-chlorination byproducts → uncondensed allyl chloride in overhead → area detector 2.8 ppm (Surface 1). All four surfaces linked from a single valve actuator failure (Surface 4 root cause).

Why is flash point −32°C significant for allyl chloride?

At any ambient temperature, allyl chloride liquid immediately generates a flammable vapor atmosphere at concentrations above the 2.9% LEL. Any spill creates a flammable vapor cloud without requiring pre-heating. AI suppression of the area vapor detector eliminates both the health (TLV-TWA 1 ppm) and flammability (pre-LEL warning) alarm simultaneously.

Why is the cooling water flow attack upward-direction?

Low flow is the dangerous condition (insufficient heat removal). The attack shifts the display upward to make 0.4 m³/hr (5% design) appear as 8.2 m³/hr (adequate). This is the deficiency-suppression upward geometry consistent across all protective-flow surfaces in the Glyphward portfolio.