Epichlorohydrin Mill & Plant Capability: Reading Capacity and Outage Signals requires the separation of nameplate capacity from demonstrated hourly mass production. Commercial ECH is routinely specified at 99.9 wt% minimum purity, with water content below 0.01 wt% and density of 1.18 g/cm³ at 20 °C when measured by ASTM D4052-22. Dynamic viscosity is near 1.03 mPa·s at 20 °C, and the atmospheric boiling range is 115–118 °C; the closed-cup flash point is 31 °C. The molecule is produced primarily through allyl chloride hydration and glycerol hydrochlorination routes, each carrying distinct capacity risk profiles. Plant capability is best read through continuous equipment output, not annual nameplate tags, because integrated chlor-alkali supply, reactor fouling, and derivative pull simultaneously impose maximum sustainable rates.

Why Do ECH Plants Report Both Nameplate and Effective Capacity?

Nameplate capacity is calculated from the design mass balance and assumed operating hours. A single ECH train designed for 200 kt/a at 8,000 h/a must sustain 25 t/h across allyl chloride reaction, dichloropropanol distillation, caustic dehydrochlorination, and epoxide recovery. Effective capacity subtracts planned turnarounds of 3–6 weeks every 3–5 years and reliability losses of 2–5%. Some operators further discount to 85–90% of nameplate for annual planning, depending on catalyst age and fouling history. The difference between nameplate and effective output becomes visible when compressor trip data are compared against monthly operating rate. Published annual reports do not always separate these terms; a 85% operating rate is ambiguous unless the underlying operating-hour base is known.

Allyl chloride-based plants face capacity bottlenecks at the propylene chlorination reactor and the dichloropropanol saponification section. Propylene chlorination is exothermic and requires rapid quench; reactor tube wall temperatures above 520 °C accelerate coke deposition and shorten furnace run length. Pressure drop across the quench train is monitored against design; a sustained rise of 15–20 kPa above clean-tube baseline typically precedes a de-coking outage. The hypochlorous acid addition step generates dichloropropanol isomers and by-product chlorinated C3 species; unless the vacuum distillation column receives sufficient reflux, high-boiling impurities accumulate and reduce ECH product quality below the 99.9 wt% specification. Caustic dehydrochlorination produces sodium chloride brine that must be purged or rebalanced. Any caustic imbalance shifts pH in the epoxide recovery column, causing polymerization of ECH in the reboiler at localized hot spots above 120 °C.

Glycerol-to-ECH Reactor Fouling and Its Capacity Signal

Glycerol-based ECH capacity is more sensitive to feed quality than propylene-based capacity. Crude glycerin containing non-glycerol organic matter, chlorides, and methanol can deactivate the acid catalyst and elevate reactor pressure drop. In fixed-bed hydrochlorination systems, pressure drop is a direct output signal: clean-bed differential pressure below 50 kPa may rise to 150–200 kPa as oligomeric glycerol by-products deposit in the catalyst pores. Once the pressure drop exceeds the recycle compressor head, production rate must be cut or the reactor taken offline for oxidative regeneration. Batch-to-batch variance in crude glycerin water content also shifts the HCl feed requirement; if water is above 12–15 wt%, the azeotropic drying load in the dichloropropanol purification train reduces achievable throughput. These effects are not captured by nameplate capacity and are only visible through hourly pressure, temperature, and feed composition data. Published data for specific crude-glycerin configurations is limited; operators rely on pilot-scale pressure-drop curves for design.

Derivative demand from liquid epoxy resin plants sets the commercial operating rate. A standard liquid epoxy resin unit consumes roughly 0.55–0.65 t ECH per tonne of BPA-based epoxy resin, depending on excess epichlorohydrin recovery efficiency. When downstream epoxy resin units run above 90% utilization, ECH plant inventory typically falls below 14–21 days of consumption unless import cargoes arrive. This relationship is measured through monthly operating-rate data and customs shipment records, not through annual capacity statements. Captive versus merchant ECH allocation also matters: a plant feeding an internal epoxy resin line may show a high nameplate capacity but low merchant availability, which distorts spot price signals.

When Unplanned Outage Data Precedes Epoxy Resin Price Movement

Unplanned ECH outages propagate into derivative pricing through inventory coverage and logistics. A sudden loss of a 100 kt/a train removes roughly 12.5 t/h of merchant supply, equivalent to 300 t/d; if the affected region holds only 10–14 days of ECH inventory, downstream liquid epoxy resin units must reduce rates within two weeks unless alternate supply is railed or shipped. Force majeure declarations under supply contracts often follow within 48–72 h of a confirmed compressor, saponification column, or epoxide recovery reboiler failure. Outage signals are therefore read from reliability data—boiler feedwater pump vibration, caustic circulation flow, overhead condenser vacuum—before price benchmarks move. Plants with continuous vibration monitoring on the allyl chloride recycle compressor and automatic shutdown interlocks on the HCl feed system transmit early warnings; a trip in the recycle compressor typically curtails production to 50–70% of nameplate within minutes, not days.

ECH storage and logistics impose their own capability cap. ECH is typically stored in stainless steel or lined carbon steel tanks under nitrogen padding, with temperature maintained below 40 °C to suppress polymerization. If ambient heat raises tank temperature above 35–40 °C, stabilizer consumption accelerates and off-test material can require re-distillation. Lined carbon steel railcars and isotainers require internal pressure relief; shipping delays beyond 10 days at terminal storage may trigger contractual off-spec notices. These constraints are operational boundaries, not nameplate capacity constraints.

Under 29 CFR 1910.119, ECH process trains must maintain mechanical integrity records for piping, compressors, and relief devices. Under 40 CFR Part 68, off-site consequence analysis documents worst-case release scenarios. ISO 14001:2015 Clause 9.1.1 requires monitoring of environmental performance, including scrubber caustic strength and flare flow. REACH (EC) No 1907/2006 registration dossiers specify exposure scenarios for downstream uses. The same data streams support capacity interpretation; a progressive decline in scrubber caustic circulation of 10–15% from baseline without a corresponding production increase indicates internal leakage or degradation, and is corrected through line cleaning or exchanger replacement before a forced outage develops.