Industrial steam boiler with capacity control — a PR-STEAM process flowsheet
A natural-gas-fired water-tube boiler raising 50 t/h of steam at 42 bar and 400 C, with its three circuits and its capacity control on one flowsheet. Fuel: methane at 3 bar to the windbox. Combustion air / flue gas: an FD fan and a regenerative air preheater feed the burner at 15% excess air; the flame (adiabatic, 2252 K) then gives up its heat to the radiant evaporator, the superheater, the economizer and the air preheater in turn, and leaves the stack at 377 K with 3.0% O₂ dry. Steam: deaerated feedwater is pumped to 48 bar, warmed in the economizer, boiled in the evaporator and separated in the drum; saturated steam is superheated to 672.2 K and 2% is blown down. Capacity control: a steam-flow controller (FIC, integral action) sets the firing rate to hold the steam demand, a ratio station keeps combustion air at 15% excess, and the drum-level balance makes feedwater equal steam plus blowdown. At design it fires 49.92 mol/s of fuel (40.0 MW LHV); the evaporator takes 25.3 MW, the economizer 7.7 MW and the superheater 5.7 MW, for a direct efficiency of 96.7% LHV / 87.1% HHV. The heat-transfer banks are rated by UA, so a change of load redistributes the heat instead of reproducing it: run the sensitivity (70-100% load) and the superheat falls from 673 K to 605 K at 70%. Property method: pr-steam, Peng-Robinson for the gas with IAPWS-95 steam tables for pure water; plain Peng-Robinson puts 18% too little heat in the superheater. Bounds: no radiation or casing loss (a real boiler loses 1-2%, so efficiency reads high, and more so at part load); no dissociation in the flame; the radiant section is a fixed-UA exchanger, which overstates its absorption at deep turndown; no attemperator; and level and ratio control are the steady-state balances, not dynamic loops.
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- Rigorous PR-STEAM thermodynamics, solved by the same engine every simulation runs on.
- 8 unit operations modeled: FDF, 4× ECO, WB, FURN, BFP, DRUM, FT, FIC.
- Focus areas: Steam boiler, Combustion, Flue gas, Air preheater, Economizer, Superheater, Drum level, Capacity control, Air/fuel ratio.
- Thermodynamics
- PR-STEAM
- Components
- methane, oxygen, n2, co2, water
- Unit operations
- FDF4× ECOWBFURNBFPDRUMFTFIC
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Read the step-by-step guideReproduce this exact result from Python — the real client.get_example() → run_and_wait() path, not a mockup.
from flowsim.sdk import FlowSimClient
client = FlowSimClient()
example = client.get_example("industrial-steam-boiler")
sim = client.create_simulation(example["title"], example["flowsheet"])
result = client.run_and_wait(sim["id"])
print(result["status"]) # "converged"
streams = client.streams(sim["id"])Related models
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