Prompt injection in maleic anhydride (MA) production AI

Four adversarial injection surfaces in maleic anhydride production AI

1. VPO catalytic oxidation reactor temperature AI (Honeywell Experion PKS MA reactor temperature AI / Yokogawa OpreX n-butane oxidation reactor AI / Emerson DeltaV APC MA catalytic reactor AI / AspenTech Aspen Manufacturing Suite VPO reactor optimizer — multi-zone thermocouple array with AI trend classification for reactor hotspot detection in fixed-bed VPO catalyst reactors)

Industrial maleic anhydride production uses fixed-bed multi-tubular reactors packed with vanadium-phosphorus oxide (VPO) catalyst, with the n-butane/air feed mixture maintained below the lower explosive limit (butane LEL 1.8 vol% in air; typical feed: 1.4–1.7 vol% n-butane in air). The reaction is highly exothermic (ΔH ≈ −1,260 kJ/mol), generating significant heat in the catalyst bed that is removed by a circulating molten-salt (eutectic KNO3/NaNO2) heat carrier flowing through the reactor shell. The VPO catalyst is active in a specific temperature range: the surface active phase — vanadyl pyrophosphate (VO)2P2O7 — performs optimally at 400–430°C. Above approximately 450°C, two simultaneous damaging effects occur: (1) the VPO catalyst begins to over-reduce, converting the active (VO)2P2O7 phase to less selective V3+ species that favor complete combustion over partial oxidation, reducing maleic anhydride selectivity and increasing CO/CO2 production; and (2) the additional exotherm from CO2 production (ΔH ≈ −2,650 kJ/mol) compounds the temperature rise in a positive-feedback loop, accelerating further catalyst degradation and increasing the risk of hot-spot formation and runaway. AI monitoring on Honeywell Experion PKS platforms continuously analyzes thermocouple array images from the multi-tube reactor bundle to classify whether the temperature profile is developing a hotspot indicative of catalyst degradation or cooling circuit failure.

In the adversarial scenario, one tube bundle zone temperature has risen to 464°C — 14°C above the 450°C design ceiling — due to partial fouling of three tubes in the molten-salt cooling circuit. At 464°C, deep oxidation to CO/CO2 is increasing the local exotherm, and the VPO catalyst in those tubes is beginning to over-reduce. A ±10 DN downward pixel-value shift on the multi-zone thermocouple dashboard image suppresses the AI's reading of the hottest zone from 464°C to 428°C: on a 350–550°C display at 200px height (1°C/px from 350°C baseline), the actual hotspot at 464°C produces a bar at 114px from baseline; the perturbed image is classified as showing approximately 78px — corresponding to 428°C — because the AI's feature extraction for multi-zone thermocouple profiles is sensitive to the 10 DN pixel perturbation on the bar-cap pixels. The AI reports "reactor temperature within normal operating envelope — no hotspot detected." No cooling circuit inspection is dispatched, no feed rate reduction is initiated, and the over-reducing catalyst zone compounds through the session without triggering any OSHA process safety response.

2. Reactor inlet n-butane feed concentration analyzer AI (Emerson Rosemount 370XA gas chromatograph AI / Yokogawa OpreX GC feed concentration AI / Honeywell Experion PKS feed composition monitoring AI — real-time n-butane/air ratio analysis at reactor inlet to maintain feed below lower explosive limit)

The n-butane oxidation route for maleic anhydride operates with a reactor inlet n-butane concentration maintained below the lower explosive limit — 1.8 vol% n-butane in air — as an absolute explosion safety constraint. The feed ratio is typically set at 1.4–1.7 vol% n-butane (78–94% of LEL), providing a margin between normal operation and the flammable envelope. If the n-butane feed rate rises above the LEL, the reactor inlet gas becomes a flammable mixture; in a fixed-bed reactor at 400–450°C with catalyst present, any ignition source can propagate a flame through the feed gas, creating an explosion risk in the reactor tubes. AI monitoring systems parse gas chromatograph readout screen images from the feed analyzer installed at the reactor inlet to continuously classify whether the n-butane concentration is within the safe sub-LEL operating envelope or is approaching or exceeding the LEL. This real-time composition monitoring is a primary process safety layer — independent of the flow-ratio control loop — because flow meter malfunctions or feed ratio control failures can cause the n-butane concentration to drift above LEL without triggering a flow alarm.

The adversarial attack uses ±8 DN downward pixel shift on the gas chromatograph display image fed to the feed composition AI. The actual n-butane concentration of 2.4 mol% — arising from a partially stuck feed control valve that has held the n-butane flow at a higher-than-setpoint rate for the past 40 minutes — is above the LEL of 1.8 mol% in air, making the reactor inlet gas a flammable mixture at the current operating conditions. On a 0–3 mol% display at 200px height (0.015 mol%/px), the actual reading of 2.4 mol% produces a display bar at 160px; the ±8 DN downward perturbed image is classified as approximately 80px — corresponding to 1.2 mol%, safely below LEL — because the GC readout display uses fine bar-chart features whose pixel intensities are highly sensitive to 8 DN perturbations. The AI reports "n-butane concentration within safe operating range — below LEL." The flammable reactor inlet gas proceeds to the multi-tube reactor at 400–450°C catalyst bed temperature, where any ignition source — catalyst hot spot, tube wall spark, or pressure transient — can initiate a detonation. OSHA PSM requirements for flammable gas explosive atmospheres (29 CFR 1910.119 and OSHA 29 CFR 1910.94) are not triggered because the AI monitoring system has been deceived into reporting a sub-LEL condition.

3. MA vapor ambient CEMS (Dräger X-am 5600 MA area monitor AI / RAE Systems MultiRAE MA detector AI / Honeywell Analytics Midas MA CEMS AI / Thermo Fisher TVA-2020 total VOC with MA-specific calibration AI — ambient air monitoring of maleic anhydride vapor in the production area for OSHA TLV-C and EPA NESHAP compliance)

Maleic anhydride has a vapor pressure of approximately 0.16 mmHg at 20°C but is typically handled at processing temperatures where vapor generation is significant; liquid MA melts at 52.8°C and has a vapor pressure of approximately 1 mmHg at 60°C, meaning the condenser and product handling areas operate with MA vapor at concentrations that can rapidly exceed the ACGIH TLV-C of 0.25 ppm. MA is a potent respiratory sensitizer: initial exposures above TLV-C cause bronchospasm, rhinitis, and conjunctivitis, and repeated sub-IDLH exposures can induce occupational asthma that persists after exposure cessation. The NIOSH IDLH of 10 ppm reflects the acute pulmonary hazard at higher concentrations. EPA NESHAP (40 CFR Part 63, Subpart HHHHH for miscellaneous organic chemical production) establishes MA vapor as a regulated HAP emission requiring continuous CEMS monitoring; EPA SARA Section 313 requires TRI reporting for MA releases above 100 lbs/year. AI monitoring systems parse CEMS trend images to classify whether the production area vapor concentration is within the TLV-C envelope or is indicating a leak or condenser failure.

The adversarial attack uses ±8 DN downward pixel shift on the MA vapor CEMS trend chart image. The actual MA concentration of 8.4 ppm — arising from a failing flange seal on the MA product rundown line between the reactor condenser and the product storage tank — is 84% of NIOSH IDLH 10 ppm and 34× the ACGIH TLV-C 0.25 ppm. On a 0–10 ppm CEMS display at 200px height (0.05 ppm/px), the actual reading produces a bar at 168px; the ±8 DN perturbed image is classified as showing approximately 3px — corresponding to 0.14 ppm, below TLV-C — because the CEMS trend-line pixel intensities are sensitive to 8 DN perturbations in the display color encoding. The AI reports "MA ambient concentration below TLV-C — within safe exposure limits." Workers in the rundown area receive no alarm and continue operating without respiratory protection, accumulating MA exposures that exceed the occupational asthma-induction threshold and the acute IDLH-approach threshold simultaneously. The EPA NESHAP CEMS record shows compliant emissions during the event; no TRI release reporting threshold is triggered. Both the occupational safety and environmental compliance monitoring pathways are suppressed simultaneously by the same ±8 DN adversarial perturbation.

4. MA product condenser cooling water flow AI (Honeywell Experion PKS condenser cooling flow AI / Emerson Micro Motion Coriolis cooling flow AI / Endress+Hauser Promag cooling circuit AI — MA product switch-condenser cooling water flow monitoring as primary heat-removal safety assurance for MA product recovery)

Maleic anhydride is recovered from the reactor product gas by condensation in switch condensers — a pair of shell-and-tube heat exchangers that alternately collect liquid MA and are then heated (switched) to melt and drain the collected product. The condenser cooling circuit removes the condensation heat from the hot MA-containing reactor effluent gas (typically 250–350°C at condenser inlet), maintaining the condenser tube surface below MA's melting point (52.8°C) to promote condensation. The cooling water flow rate is the primary manipulated variable for condenser temperature control; a reduction in cooling flow raises the condenser tube surface temperature toward and above MA's melting point, reducing condensation efficiency and allowing MA vapor to pass through the condenser uncondensed to the stack exhaust — an EPA NESHAP emission event. At severely reduced cooling flow, the condenser tube surface temperature may reach 80–100°C, where MA remains largely uncondensed and the product recovery efficiency collapses. Beyond the emission compliance issue, uncondensed MA vapor in the switch-condenser off-gas stream then passes to the thermal oxidizer or stack, reducing product yield and potentially exceeding stack emission limits.

This surface uses the upward-direction attack geometry: the cooling water flow has failed to 0.8 m³/h (10% of the design 8.0 m³/h) due to a failing pump bearing. The dangerous condition is a deficiency — too little cooling — and the adversarial pixel perturbation shifts the cooling flow indicator display upward by ±8 DN to make the actual 0.8 m³/h appear as 8.4 m³/h. On a 0–10 m³/h display at 200px height (0.05 m³/h per pixel), the actual flow of 0.8 m³/h produces a bar at 16px; the upward-perturbed image is classified as approximately 168px — corresponding to 8.4 m³/h (design setpoint). The AI monitoring reports "condenser cooling flow at design setpoint — MA condensation adequate." The condenser begins warming; MA passes the condenser uncondensed and appears in the process area as the vapor plume measured by Surface 3. The compound attack — condenser cooling failure shown as adequate (Surface 4) and the resulting MA vapor release shown as sub-TLV-C (Surface 3) — simultaneously suppresses the root cause and the consequence, leaving the EPA NESHAP CEMS record clean and the OSHA PEL monitoring record clean during an event that is generating both a TRI-reportable MA release and a worker IDLH-approach exposure. Glyphward intercepts both images at threshold 35 before any AI monitoring pipeline processes them.

Integration: maleic anhydride production AI with Glyphward pre-scan gate

Glyphward integrates as a pre-scan gate between the DCS and analyzer screenshot capture and the AI inference pipeline for each MA production monitoring context. If the adversarial score meets or exceeds threshold 35 — reflecting the ACGIH TLV-C ceiling of 0.25 ppm, NIOSH IDLH of 10 ppm, OSHA 1910.1000 PEL, EPA NESHAP HAP classification, and the compound four-surface attack geometry that simultaneously suppresses reactor safety, LEL explosion hazard, ambient exposure, and product-loss indicators — the scan raises AdversarialMAProductionImageError 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"

# MA production AI contexts: threshold 35
# OSHA 29 CFR 1910.1000 Table Z-1 PEL 0.25 ppm (1 mg/m3) TWA
# ACGIH TLV-C 0.25 ppm (ceiling -- never exceed)
# NIOSH IDLH 10 ppm
# EPA NESHAP 40 CFR Part 63 HAP; SARA 313 TRI reportable
# n-Butane LEL 1.8 vol% in air (explosion hazard above LEL in reactor)
# NFPA 704: Health 3, Flammability 1 (dust explosion Kst 117 bar.m/s)
MA_THRESHOLD = 35


class MAProductionContext(Enum):
    REACTOR_TEMPERATURE = "reactor_temperature"
    FEED_BUTANE_CONCENTRATION = "feed_butane_concentration"
    VAPOR_CEMS = "vapor_cems"
    CONDENSER_COOLING_FLOW = "condenser_cooling_flow"


class AdversarialMAProductionImageError(Exception):
    """Raised when any MA production monitoring image scores >= 35.
    REACTOR_TEMPERATURE uncaught: 464C deep-oxidation hotspot shown as 428C.
    FEED_BUTANE_CONCENTRATION uncaught: 2.4 mol% (above LEL) shown as 1.2 mol%.
    VAPOR_CEMS uncaught: 8.4 ppm (84% IDLH, 34x TLV-C) shown as 0.14 ppm.
    CONDENSER_COOLING_FLOW uncaught: 0.8 m3/h (10% design) shown as 8.4 m3/h."""

    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 MA production image: context={context.value} "
            f"score={score} unit={unit_id} scan_id={scan_id}"
        )


async def scan_ma_production_image(image_bytes, context, unit_id, client):
    image_hash = hashlib.sha256(image_bytes).hexdigest()
    payload = {
        "image": base64.b64encode(image_bytes).decode(),
        "source": f"ma_production:{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) >= MA_THRESHOLD:
        raise AdversarialMAProductionImageError(
            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("ma_reactor_screenshot.png", "rb") as f:
            image_bytes = f.read()
        result = await scan_ma_production_image(
            image_bytes,
            MAProductionContext.REACTOR_TEMPERATURE,
            unit_id="MA-REACTOR-R-01",
            client=client,
        )
        print(f"Clean scan: {result['scan_id']} score={result['score']}")


asyncio.run(main())

Frequently asked questions

Why does operating above the n-butane LEL in an MA reactor pose an explosion risk?

The fixed-bed VPO reactor operates at 400–450°C — near or above n-butane's auto-ignition temperature of 405°C. If the feed concentration exceeds LEL (1.8 vol%), the reactor inlet becomes a flammable mixture at auto-ignition temperature, where any hot surface, pressure transient, or catalyst over-temperature event can initiate flame propagation. In a multi-tubular reactor at high linear gas velocity, detonation rather than deflagration can result, producing overpressure sufficient to fragment the reactor vessel. OSHA PSM applies to n-butane at TQ 10,000 lbs for facilities holding that quantity — requiring PHA of this exact scenario.

What are the consequences of MA exposure near the NIOSH IDLH?

ACGIH TLV-C is 0.25 ppm (ceiling, never exceed) reflecting MA's potent respiratory-sensitization effects — even brief exceedances can initiate occupational asthma that persists for years after cessation of exposure. NIOSH IDLH 10 ppm: acute bronchospasm and laryngeal edema in unprotected workers within minutes. At the adversarial scenario's 8.4 ppm (84% IDLH), sensitized workers face life-threatening bronchospasm and all workers face irreversible pulmonary injury without alarm, protection, or post-exposure monitoring.

How does VPO over-reduction above 450°C create a self-amplifying exotherm?

Above ~450°C, V4+ (active for partial oxidation to MA) over-reduces to V3+ (active for complete combustion to CO/CO2). Complete combustion releases −2,650 kJ/mol vs. −1,260 kJ/mol for MA synthesis — a self-amplifying positive feedback: higher temp → more V3+ → more combustion → more heat → higher temp. Adversarial suppression of the 464°C hotspot to appear 428°C prevents the cooling-augmentation response before this loop enters acceleration phase.

Why is the condenser cooling flow attack upward-direction?

The dangerous condition is cooling deficiency (0.8 m³/h vs. 8.0 m³/h design). Suppressing low flow requires showing more flow than exists: upward pixel shift displays 8.4 m³/h (adequate) when actual is 0.8 m³/h (near-zero). Upward attacks target safety-protective deficits; downward attacks target hazardous excesses.

Why is threshold 35 for MA production AI?

Threshold 35 reflects ACGIH TLV-C ceiling 0.25 ppm, NIOSH IDLH 10 ppm, EPA NESHAP HAP classification, n-butane explosive hazard above LEL in hot reactor, VPO catalyst self-amplifying exotherm above 450°C, and the compound four-surface attack that simultaneously suppresses reactor safety, LEL explosion hazard, ambient exposure, and product-loss indicators — eliminating all independent PHA safeguard-layer alarm pathways at once.