Saturated / superheated steam properties from the IAPWS-IF97 formulation. Educational approximation — verify against NIST/IIR tables for real work.
Tube Material & Creep Check
API RP 530-style Larson–Miller creep check against the radiant wall-temperature profile. Uses tube OD / wall / internal pressure from the Radiant inputs above. Representative material data for educational use — verify against ASME II-D / API 530 before design.
Sensitivity / What-if Scan
Scan results
Varies one input across the range and re-runs the full model (combustion → radiant → tubes → convection → draft → creep). Use it to see how tube wall temperature, absorbed duty, pressure drop or creep margin respond. In vaporizing (two-phase) mode the duty is fixed by the bubble-point override, so varying outlet temperature has no effect.
Stack & Draft
Convection Section
Tube bank geometry
Air Preheater & Fans
Cost & Economics
Parametric order-of-magnitude estimate. All figures are converted to the currency matching the current UI language (USD / CNY / KRW / JPY / EUR / BRL). Educational only — not a quotation.
Lining / Wall Loss
Lining layers (inside → outside)
1-D conduction through the lining layers, balanced against combined radiation + convection from the casing to ambient. Hot-face temperature defaults to the firebox gas temperature. Educational model — verify against API 560 practice.
Combustion Calculator
Component mole fractions (%, sum≈100)
Burner rating (API 537)
Reburn / low-NOx staging
Radiant Section
Flame radiation source (F1)
Models the flame as a separate luminous radiating source: soot-luminous emissivity, axial heat-release profile, and the flame-to-tube direct radiative fraction. Off by default (legacy well-stirred gas behaviour).
Process-side film coefficient & fouling
Optional. With auto-hᵢ on, the inside coefficient is computed from the flow and fluid properties (Dittus–Boelter single-phase, Chen 1963 two-phase) instead of the manual entry above. Fouling is added in series as 1/h_eff = 1/h_clean + R_f, using API 530-style inside-area resistances.
Peng–Robinson property package (F2)
Optional. Replaces the generic fluid library with a real Peng–Robinson (1976) equation of state on the actual stream composition: Rachford–Rice flash, bubble/dew envelope, density and viscosity at the coil inlet, mean and outlet. Petroleum cuts are characterized by Riazi–Daubert (1987) and enter the flash as pseudo-components. With "use for hᵢ" on, the flashed ρ, µ and vapour quality drive the inside-film correlation.
Return bends & headers (Tier2-a)
Discrete form losses for the 180° return bends and the inlet/outlet headers, reported separately as dP_circuit. The legacy dP_total keeps the equivalent-length treatment so existing cases are unchanged.
Process
Pick a fluid to auto-fill process properties at the inlet temperature. Values are representative open-literature correlations for educational use.
Petroleum characterization (API estimate)
Estimated from API gravity via Riazi–Daubert & ASTM D341; indicative only.
Design mode — auto-size radiant tubes
Process outlet is the target; tube count is solved automatically.
Key results across all modules — recalculated live on every Run.
Emissions estimate
Burner / flame distribution
Compliance report
Structured pass/fail checks against common fired-heater design limits. Educational approximation — verify against ASME/API for real jobs.
Select saved cases to compare
Furnace cross-section
Standard benchmark validation
Fixed benchmark cases compared against published reference values (Perry, GPSA, Hottel, API 530, Wilson–Lobo–Evans, NIST). Independent of the current inputs.
End-to-end validation against published worked examples
Unlike the unit benchmarks above, these run complete published heater examples through the whole chain — combustion → radiant → tubes → convection → draft → efficiency — and compare the model against the numbers quoted in the source. This is the closest thing to an overall heat-balance audit of the program.
Flame-model benchmark validation (F1-b)
Validates the strict luminous-flame emissivity ε_f and the volumetric Monte-Carlo flame source against published references and the API 560 guideline furnace.
Steam Table (IAPWS-IF97)
Cost & Economics
Auto-optimizer (G7)
Searches one design variable to optimize an objective across the full model (coarse grid + golden-section refinement). Distinct from the sensitivity scan, which only plots. Educational tool — verify against engineering judgment.
API 560 / 530 standard report
Layout follows API STD 560 (fired heaters) and API STD 530 (tube thickness) for educational review. Not a certified engineering document — verify against the latest API standards.
Pressure-relief sizing (API 521 / 520)
External pool-fire heat input (API 521) drives the required relief vapor rate; the PSV area is sized by the API 520 critical-flow equation with API 526 orifice selection. Educational tool — verify against the current API standards before design use.
Reformer tube kinetics (steam-methane reforming)
Rates the catalyst-filled radiant tubes as a 1-D plug-flow reactor using the Xu–Froment (1989) kinetics, driven by the radiant duty absorbed from the firebox. Outlet conversion, temperature / pressure profiles, and coking (carbon-formation) limits are computed. Educational model — verify against the current API / process-design standards.
Multi-Case Rating
Rate the current design across operating scenarios. Each case overlays overrides on the live inputs; pass/fail is judged against API 530 limits (peak flux, tube-wall temperature, creep, minimum wall, draft).
Uncertainty analysis (Monte Carlo)
Propagates input uncertainties through the full model to give P10/P50/P90 of the chosen metric. Educational — not a formal risk assessment.
Uncertain inputs (ticked = varied)
Steam Cracking & Visbreaking
Reaction-coil rating for olefins (steam cracking) and residue (visbreaking) furnaces. Educational tool — verify against current standards before design use.
Multi-Heater Train Rating
Rate a train of heaters built from the current design with per-heater overlays. Stages sharing a group run in parallel; groups run in series with optional inter-stage ΔT. Educational tool.
Soot Blowing & Cleaning Schedule
Gas-side fouling raises stack temperature and cuts duty. Soot blowing removes most deposit; an offline clean triggers when the permanent layer hits its limit. Optimises the blowing interval for minimum annual cost. Educational tool.
Fired-Heater Acoustics (API 615/618)
Octave-band sound power for combustion roar, fuel-gas jet mixing, fans and stack radiation. Operator position and plant boundary propagate with hemispherical divergence + ISO 9613-2 absorption. API 615 equipment limit rated 1 m from each item. Educational tool.
DXF Geometry Export
Exports the solved heater arrangement as an AutoCAD R12 (AC1009) ASCII DXF: plan, elevation and convection-bank detail, laid out side by side in metres. Download the file and open it in any CAD viewer.
Natural-Circulation Steam Coil
Rates a convection-bank steam-generating coil on natural circulation: buoyancy driving head vs two-phase friction/acceleration/fitting losses, solved by bisection. Checks CR, exit quality, DNB (Bowring 1972) and Ledinegg stability. Educational tool.
Site / Meteorological Corrections
Adjusts the datasheet for site altitude, temperature, humidity and wind. Draught scales with barometric pressure, fan volume/speed/power with 1/ρ, and moisture adds stack loss and raises the dew point. Wind is a structural check on the stack. Educational tool.