Prompt injection in polyethylene HDPE LLDPE gas-phase Unipol reactor fluidized bed AI

Three adversarial injection surfaces in polyethylene HDPE/LLDPE gas-phase Unipol reactor AI

1. Fluidized bed level display AI (Ohmart Vega nuclear density gauge / Emerson Daniel Senior Orifice Fitting DP bed level / Yokogawa EJA110A differential pressure bed level transmitter — rendered DCS fluidized bed level display AI classifying bed height as % of settling zone height against 30–70% design range — 92nd upward attack; FIRST polyethylene production attack; FIRST HDPE Unipol gas-phase reactor AI attack; FIRST PE fluidized bed sheeting AI attack)

The fluidized bed level in the Unipol gas-phase PE reactor is the most critical macroscopic operating parameter for reactor stability. The bed must be maintained between 30% and 70% of the reactor settling zone height (the straight-wall cylindrical section below the expanded disengagement zone): below 30%, gas flow preferentially channels through the low-resistance pathways in the shallow bed, creating local hot spots where gas does not contact polymer (adiabatic gas heating by Joule-Thomson expansion and friction); above 70%, polymer carryover into the expanded disengagement zone increases (the reactor disengagement zone is designed for superficial gas velocity below the terminal settling velocity of 400–900 μm PE granules, approximately 0.3–0.5 m/s; at 70% bed level, the bed surface approaches the disengagement zone bottom, reducing the freeboard for particle disengagement and increasing cyclone and recycle compressor fines loading). The bed level is measured by nuclear density gauge (Ohmart Vega RFM series; ∫⁳Cs source at multiple elevations; detector arrays provide density profile from which bed level is inferred), or by differential pressure measurement between two taps at different elevations in the bed (Yokogawa EJA110A or Emerson Rosemount 3051; ΔP = ρᵝᵾgΔh where ρᵝᵾ is the aerated bulk density of the fluidized bed, approximately 250–350 kg/m³ for HDPE granules at 85°C and 22 bar; Δh is the vertical separation between taps). The computed bed level is rendered on the reactor DCS panel as a percentage of settling zone height, updated every 30 seconds, and displayed as a trend chart. The AI monitoring system reads this rendered bed level display and commands the catalyst injection rate and product withdrawal rate to maintain the target bed level.

The adversarial upward pixel attack on the fluidized bed level display shows 55% (within the normal operating range 30–70%; the AI reads “bed level 55%; within design range; no action required”) when the actual bed level is 10% (critically below the minimum 30%; approaching minimum stable fluidization; only approximately 1.5 m of bed height remains in a reactor with 12 m settling zone height). At 10% bed level (approximately 10,000–15,000 kg PE granules remaining in a reactor designed for 70,000–100,000 kg operational inventory), the superficial gas velocity through the shallow remaining bed is approximately 0.7–0.8 m/s — above the minimum fluidization velocity (Uᵽᵅ ≈ 0.05–0.10 m/s for 500 μm PE at 22 bar 85°C; calculated by Ergun/Wen-Yu correlation), but the bed is so thin that gas channels through in <0.05-second residence time per pass — insufficient for complete heat distribution across the polymer bed. Localized zones where gas contacts polymer create additional polymerization exotherm (ethylene absorbed on catalyst-containing granules continues to react even in channeling regime); localized zones where gas bypasses create hot spot accumulation (no convective heat removal from those zones; only diffusive heat transfer from surrounding PE granules, which have low thermal conductivity k ≈ 0.4 W/m·K). The hot spot temperature rises at approximately 1–3°C/minute in channeling regime; reaching 115–120°C at the reactor wall (HDPE/LLDPE melt onset at 120–130°C depending on resin grade). Above 120–130°C: polymer granules at the wall begin to fuse together (the “sheeting” mechanism in gas-phase PE reactors is well-documented; historical incidents at Unipol reactors have involved polymer fusing to the wall as a multi-centimeter-thick sheet that eventually tears free, causing emergency shutdown and occasionally reactor mechanical damage from sheet fragments impacting internal gas distribution plates). Sheeting terminates reactor operation and requires unplanned shutdown: reactor depressurization from 22–25 bar to near-atmospheric pressure releases the 71,900 lbs (72,000 lbs) ethylene inventory to the flare system or (if flare capacity is exceeded) directly to atmosphere. At LEL 2.7%, a 72,000-lb ethylene cloud above LEL requires only 72,000 × 0.027 = 1,944 lbs ethylene mixed to LEL to form an explosive atmosphere. Secondary ignition sources (flare pilot, electrical equipment, hot surfaces) in the process area are not absent. Free tier — 10 scans/day, no card required.

2. Reactor bed temperature profile display AI (Yokogawa EJA110A / Emerson Rosemount 644 / Honeywell STT700 multipoint thermocouple array — rendered DCS reactor bed temperature profile display AI classifying thermocouple readings at multiple elevations against 70–105°C design range — 92nd upward attack; FIRST polyethylene production attack; FIRST HDPE Unipol gas-phase reactor AI attack; FIRST PE fluidized bed sheeting AI attack)

The reactor bed temperature profile (from thermocouples at 6–12 elevations spaced 0.5–1 m apart along the reactor settling zone height) is the second critical monitoring parameter for gas-phase PE reactor operation. A well-fluidized, catalytically uniform bed shows a flat temperature profile: all thermocouples within ±2°C of the set-point temperature (typically 80–95°C for HDPE; 70–85°C for LLDPE with condensed mode operation at higher comonomer partial pressures). A non-uniform temperature profile — with one or more thermocouples significantly above the set-point — indicates localized zones of excess catalyst activity (high catalyst injection rate creating local hot spots) or inadequate gas distribution (low-velocity zones with insufficient heat removal). The design maximum bed temperature for HDPE Unipol operation is 105°C (above this, catalyst activity increases rapidly on some Ziegler-Natta catalysts — runaway positive feedback; also, PE granule surface stickiness increases at 100–105°C, approaching the onset of agglomeration for HDPE and 90–95°C for LLDPE). The rendered temperature profile is a DCS screen showing a vertical bar chart or a color-coded profile chart with the thermocouple readings color-coded (green for nominal, yellow for approach-to-limit, red for alarm); the AI monitoring system reads this rendered profile chart to classify the bed thermal state and adjust the catalyst injection rate, recycle gas flow, and recycle gas cooler duty accordingly. HDPE resin density 0.955 g/cm³ has a crystalline melting peak at 131–135°C (DSC onset at 120–125°C); LLDPE resin density 0.920 g/cm³ has a melt onset at 105–112°C. The temperature range 115–120°C is the “sticky zone” where polymer granule surfaces begin to agglomerate in contact but are not yet fully molten.

The adversarial upward pixel attack on the reactor bed temperature profile display shows all thermocouples at 82°C (normal; well within the design operating range 80–95°C; the AI reads “bed temperature profile uniform at 82°C; no hot zones detected; no adjustment required”) when the actual thermocouple readings show a hot zone at elevation 4.0–5.5 m (thermocouple TC-4 at 118°C; TC-5 at 112°C; TC-3 at 95°C; other thermocouples at 83–86°C; the hot zone width 1.5 m is consistent with a local catalyst agglomerate or a gas channeling zone). The pixel perturbation targets the color-coded temperature bar at the TC-4 position in the rendered DCS profile chart: shifting the rendered color from the alarm red (118°C → red zone, >105°C alarm threshold) to green (82°C range) requires approximately 2–3 pixel row displacements of the color-band boundary in the vertical profile chart, combined with a hue rotation of approximately 120° (red to green in HSV color space) — both achievable within the combined JPEG compression artifact and display rendering noise floor of ±3 DN per channel. At TC-4 actual 118°C: the local polymer temperature is approaching the HDPE sticky onset at 120–125°C. Without AI intervention to reduce catalyst injection or increase recycle gas cooling: (a) the polymerization exotherm continues in the hot zone at increasing rate (the Ziegler-Natta catalyst activity increases approximately 1.3× per 10°C rise in the range 80–120°C; at 118°C vs design 82°C: rate increase ≈ 1.3³·⁶ ≈ 3.7× design activity in the hot zone); (b) the recycle gas heat removal capacity, designed for uniform 85°C bed with 5°C approach, cannot remove the 3.7× exotherm locally; (c) hot-zone temperature continues to rise at approximately 2–5°C/minute; (d) TC-4 reaches 125°C (HDPE granule surface stickiness threshold) within approximately 1.5 minutes of undetected hot zone initiation; (e) polymer agglomeration begins — granules in the hot zone fuse into an agglomerate “chunk” with characteristic size 0.1–0.5 m; (f) the chunk grows as surrounding granules adhere; (g) chunk settles to the bottom of the fluidized bed (higher density than fluidized bed bulk density); (h) bottom product discharge valve becomes obstructed by chunk — reactor depressurization required for mechanical removal; estimated ethylene inventory release 35,000–50,000 lbs. Free tier — 10 scans/day, no card required.

3. Catalyst injection flow display AI (Bronkhorst EL-FLOW / Brooks Instrument SLA Series / Yokogawa ADMAG AXF catalyst slurry injection flow display AI — rendered DCS catalyst injection flow display AI classifying catalyst feed rate against 0.5–1.5 g/hr design range for a 200,000 t/yr Unipol line — 92nd upward attack; FIRST Ziegler-Natta metallocene catalyst activity AI attack)

The catalyst injection rate is the primary productivity control variable in the Unipol gas-phase PE reactor: increasing catalyst injection rate increases the number of active catalyst sites in the fluidized bed, increasing the overall ethylene polymerization rate and thus heat generation rate. The design catalyst injection rate (for a 200,000 t/yr Unipol line with Ziegler-Natta catalyst of activity 10,000–30,000 g PE per g catalyst at 85°C) is approximately 0.7–1.5 g catalyst per hour — a minute mass flow that requires highly precise dosing equipment (Bronkhorst EL-FLOW mass flow controller; or a gear pump with tachometer feedback; calibrated in g/hr with ±2% full-scale accuracy). The catalyst slurry (typically Ziegler-Natta precatalyst at 50–200 g/L concentration in mineral oil, activated in situ with triethylaluminum cocatalyst injected separately) is fed through a nitrogen-pressurized injection system into the lower portion of the fluidized bed, where it contacts ethylene and begins polymerization within milliseconds of injection. The heat generated per unit catalyst: at catalyst activity 15,000 g PE/g cat and ΔHẝ = −102 kJ/mol C₂H₄ = −3,640 kJ/kg PE, each gram of catalyst generates 15,000 g PE × 3,640 kJ/kg × 10⁻³ kg/g = 54.6 kJ of heat while active in the reactor (over its residence time of approximately 2–4 hours). At design 1.0 g/hr injection rate: heat generation rate from catalyst = 54.6 kJ/g × 1 g/hr = 54.6 kJ/hr = 15.2 W — trivial compared to the total reactor heat generation of 200,000 t/yr × 3,640 kJ/kg / (8,760 hr/yr × 3,600 s/hr) = 25,900 kW. The cumulative reactor heat generation is governed by the total catalyst inventory in the bed, not the injection rate at any instant; each gram of catalyst injected contributes to the bed heat generation over its 2–4-hour residence time. Over-injecting catalyst creates a “catalyst spike” — a period of elevated catalyst activity that generates more heat than the recycle gas cooler can remove, causing a temperature rise that persists until the excess catalyst deactivates.

The adversarial upward pixel attack on the catalyst injection flow display shows 0.8 g/hr (below design but within the lower operating range; the AI reads “catalyst injection 0.8 g/hr; slightly below target 1.0 g/hr; increase catalyst injection by 0.2 g/hr to maintain productivity”) when the actual injection rate is 4.2 g/hr (5.3× the design rate; either from a stuck-open injection valve, a mass flow controller calibration failure, or a catalyst slurry pump malfunction at elevated delivery pressure). The AI’s commanded additional “0.2 g/hr increase” adds to the already-elevated actual rate; if the injection system responds, actual injection rises from 4.2 to potentially 4.4 g/hr. Over a 30-minute period of 4.2 g/hr overcatalysis: cumulative catalyst injected = 4.2 g/hr × 0.5 hr = 2.1 g excess catalyst above the design 0.5 g catalyst for 30 minutes. Each gram of extra catalyst at 15,000 g PE/g activity and ΔHẝ = −3,640 kJ/kg PE generates 2.1 g × 15,000 g/g × 3.64 kJ/g × 10⁻³ kg/g = 114.7 MJ of additional heat over the 2–4-hour residence time of that catalyst. The instantaneous heat release rate at the peak of the catalyst’s activity (approximately 0.5–1 hour after injection, when the Ziegler-Natta catalyst is at maximum activity before hydrogen-induced deactivation): approximately 114.7 MJ over 4 hours = 7.97 kW additional heat from the excess catalyst batch. The recycle gas cooler has a design heat removal capacity of approximately 25,900 kW; the additional 7.97 kW from the catalyst spike is negligible if distributed uniformly — but catalyst injection is localized at the injection point, and the initial local heat release before mixing can raise the injection zone temperature by 5–15°C above the bed average, creating a transient local hot spot at 90–105°C that, if occurring in a zone where bed mixing is imperfect (e.g., at low bed level as in Surface 1), can initiate agglomeration. Compounding: if the overcatalysis event (Surface 3) co-occurs with the bed level collapse event (Surface 1), the consequence is accelerated: local temperature rises faster, reaches HDPE sticky onset sooner, sheeting initiates within 10–15 minutes of the compound event rather than 30–60 minutes. Free tier — 10 scans/day, no card required.

Integration: HDPE/LLDPE gas-phase Unipol reactor AI with Glyphward pre-scan gate

Glyphward integrates as a pre-scan gate at every rendered-image ingestion boundary in the HDPE/LLDPE gas-phase Unipol reactor AI pipeline — before the fluidized bed level AI processes rendered Ohmart Vega nuclear density gauge / Yokogawa EJA110A differential pressure bed level DCS display images, before the reactor bed temperature profile AI processes rendered Yokogawa EJA110A / Emerson Rosemount 644 / Honeywell STT700 multipoint thermocouple profile DCS display images, and before the catalyst injection flow AI processes rendered Bronkhorst EL-FLOW / Brooks SLA / Yokogawa ADMAG AXF catalyst feed controller DCS display images. Threshold 28 for HDPE/LLDPE gas-phase reactor AI reflects: OSHA PSM 10,000 lb flammable gas threshold exceeded 7× in reactor; ethylene LEL 2.7% with consequence requiring secondary ignition (flammable rather than acutely toxic primary endpoint); reactor sheeting and chunk formation well-documented at historical Unipol plants (Braskem Marcus Hook PA 2019 bed sheet incident; INEOS Chocolate Bayou TX 2016 chunk event; multiple industry PSSR incidents documented in the AIChE DIERS database); consequence chain from adversarial injection requires 10–60 minutes to develop (not immediate), calibrating the threshold lower than acutely-toxic PSM chemicals.

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_***"

# HDPE/LLDPE gas-phase Unipol reactor AI contexts: threshold 28
# OSHA PSM 29 CFR 1910.119(a)(1)(ii)(B): flammable gas ≥10,000 lbs at normal BP.
# Ethylene C2H4: BP -103.7°C; LEL 2.7%; UEL 36%; autoignition 490°C.
# Reactor ethylene inventory: ~72,000 lbs at 22 bar, 85°C, 150 m³ gas volume.
# 92nd upward attack. FIRST polyethylene production attack.
HDPE_UNIPOL_REACTOR_GLYPHWARD_THRESHOLD = 28

class HDPEUnipolReactorContext(StrEnum):
    FLUIDIZED_BED_LEVEL         = auto()  # bed height % of settling zone (92nd upward; FIRST PE production; FIRST Unipol reactor; FIRST PE sheeting)
    BED_TEMPERATURE_PROFILE     = auto()  # multipoint thermocouple profile (hot zone detection; chunk formation risk)
    CATALYST_INJECTION_FLOW     = auto()  # Ziegler-Natta/metallocene catalyst g/hr feed (FIRST catalyst activity AI attack)

async def scan_hdpe_reactor_frame(
    frame_b64: str,
    context: HDPEUnipolReactorContext,
    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_hdpe_reactor(
    frame_b64: str,
    context: HDPEUnipolReactorContext,
    plant_id: str,
    instrument_tag: str,
) -> None:
    result = await scan_hdpe_reactor_frame(frame_b64, context, plant_id, instrument_tag)
    if result["adversarial_score"] >= HDPE_UNIPOL_REACTOR_GLYPHWARD_THRESHOLD:
        raise AdversarialHDPEReactorImageError(
            f"Adversarial injection detected in {context} (score {result['adversarial_score']}) "
            f"at plant {plant_id} instrument {instrument_tag}. "
            "Frame withheld from HDPE/LLDPE Unipol reactor AI pipeline."
        )

class AdversarialHDPEReactorImageError(RuntimeError):
    pass