Delayed-coking yield and utility screening balances

RefineryDelayedCokingYieldBalance and RefineryDelayedCokingUtilityBalance provide a transparent screening bridge from a residue-feed scenario to gas, naphtha, light coker gas oil (LCGO), heavy coker gas oil (HCGO), petroleum coke, unconverted residue, process duty, fuel, and steam. Every conversion, yield, and utility intensity is caller supplied.

Capability boundary

The yield receipt applies a caller-owned conversion to fresh residue feed and allocates converted feed among five product lumps. The utility receipt applies caller-owned specific process duty, furnace efficiency, fuel lower heating value, and steam intensity on the same fresh-feed basis.

These classes do not predict conversion, yields, kinetics, cracking severity, coke quality, heater coking, drum cycle, pressure or temperature, fractionator performance, recycle, product properties, fuel composition, emissions, blowdown, decoking, or safe operability. This is not a furnace design or fired-equipment rating. Qualify all scenario inputs independently for the feed, equipment, and operating envelope.

Equations

For fresh-feed mass flow (F), conversion (X), and converted-feed fractions (y_i):

[ F_{\mathrm{converted}}=FX, \qquad F_i=FXy_i, \qquad F_{\mathrm{unconverted}}=F(1-X), \qquad \sum_i y_i=1. ]

For specific process duty (q), furnace efficiency (\eta), fuel lower heating value (LHV), and steam intensity (s):

[ Q_{\mathrm{process}}=Fq, \qquad \dot m_{\mathrm{fuel}}=\frac{Fq}{\eta LHV}, \qquad \dot m_{\mathrm{steam}}=\frac{Fs}{1000}. ]

Java example

RefineryDelayedCokingYieldBalance yield = RefineryDelayedCokingYieldBalance.calculate(
    1000.0, 0.70, 0.08, 0.18, 0.32, 0.22, 0.20);
RefineryDelayedCokingUtilityBalance utility = RefineryDelayedCokingUtilityBalance.calculate(
    yield, 2.0, 0.85, 45.0, 50.0);

This synthetic acceptance case gives 700 kg/h converted feed and 300 kg/h unconverted residue. The converted products are 56 kg/h gas, 126 kg/h naphtha, 224 kg/h LCGO, 154 kg/h HCGO, and 140 kg/h coke. The utility receipt gives 0.555555556 MW useful process duty, 52.287581699 kg/h fuel, and 50 kg/h steam, with mass and useful-energy residuals zero to numerical precision.

Public provenance

• U.S. EPA AP-42 section 5.1 describes coking as thermal cracking of residual oil to petroleum coke, gas oils, and lighter stocks, and describes the delayed-coker heater, drums, steam injection, and fractionator: https://gaftp.epa.gov/ap42/ch05/s01/final/c05s01_jan1995.pdf
• U.S. Department of Energy, Factors Affecting U.S. Petroleum Refining, describes public refinery conversion pathways and delayed-coking product families: https://www.energy.gov/sites/default/files/2022-11/1973-Factors_Affecting_US_Petroleum_Refining-Impact_of_New_Tech.pdf

No proprietary assay, commercial-simulator data, fitted correlation, or copyrighted table is embedded. The numerical example is transparent synthetic scenario data and is not a literature yield benchmark.

Validation and use

Require converted-feed fractions to sum to one. Verify converted-product and overall mass residuals and the utility useful-energy residual. Test nearby conversion, efficiency, and intensity assumptions only after their physical range has been independently justified. This evidence-ladder level is analytical conservation and dimensional consistency. It is not evidence that a delayed coker operating point is feasible or safe.