Phosphoric acid concentration: steam evaporator baseline (29 → 54% P2O5) — a STEAM process flowsheet
The conventional wet-process step, at the scale of one Jorf Lasfar concentration line: 138 t/h of 29% P₂O₅ acid, heated by 3.5 bar LP steam in a graphite exchanger and flashed under vacuum (0.12 bar) to 54% P₂O₅, evaporating 64.0 t/h of water. The steam feed is tuned so the concentrate lands on 54.0 wt% P₂O₅ (the user variable p2o5_wt_product), which takes 70.4 t/h of steam — 1.76 t steam per tonne of P₂O₅, 42.6 MW of condensing duty. That is the single-effect ideal; the published plant benchmark of ~2.8 t/t carries exchanger approach, losses and off-design operation on top. The point of the number here is what it costs the site: at Jorf Lasfar this steam is a co-product of the exothermic sulfuric-acid plants, which is the fact any electric alternative has to beat. Compare the two sibling examples, phosphoric-acid-concentration-microwave and -hybrid. Model scope, stated up front. No property package in the tree can flash aqueous phosphoric acid honestly: the databank carries no heat capacity for H₃PO₄, NRTL has no binary and no UNIFAC groups for it, and the cubic equations of state give a boiling-point elevation of the wrong sign and an enthalpy flash that vaporised most of the feed from a 1 MW input. So this is the water-side model on IAPWS steam tables: the streams carry the acid's water only, and the 55.2 t/h of H₃PO₄ (40.0 t/h as P₂O₅) ride along as a non-volatile spectator in the mass balance the user variables compute. What that gets right is what the comparison turns on — the water removed and its latent heat, exact from IAPWS. What it leaves out, and by how much: the acid's own boiling-point elevation (tens of kelvin at 54% P₂O₅ — 85 wt% acid boils at 158 °C at atmospheric pressure — so the real acid runs 20-30 K hotter than these flash temperatures and the 320 K feed here stands in for a hotter plant feed), and the acid's sensible heat (of order 5% of the latent duty). Both move the temperatures, not the energy-carrier comparison. The water heated at 1 atm here reaches its 1-atm boiling point in the exchanger; the real acid is kept liquid under static head and flashes in the chamber.
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- Rigorous STEAM thermodynamics, solved by the same engine every simulation runs on.
- 2 unit operations modeled: HX, Flash.
- Focus areas: Phosphoric acid, Evaporation, Steam, Vacuum flash, Comparison study.
- Thermodynamics
- STEAM
- Components
- water
- Unit operations
- HXFlash
Opens in a new tab, loaded straight into the app — no setup.
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("phosphoric-acid-concentration-steam")
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
Phosphoric acid concentration: microwave heating (29 → 54% P2O5)
The same duty with the steam exchanger replaced by volumetric microwave heating: 42.6 MW absorbed in the acid, then the same vacuum flash to 54.0 wt% P₂O₅ and the same 64.0 t/h of water removed — the microwave does not remove water, it supplies the latent heat. At a 65% wall-plug magnetron efficiency (915 MHz industrial units reach ~85%) that is 65.5 MW of electricity, 1,640 kWh per tonne of P₂O₅ (1,250 at 85%). The comparison that decides it is the energy carrier, not the heating mechanism: at Jorf Lasfar the baseline's 1.76 t/t of steam is a co-product of the sulfuric-acid plants, and the site turns that steam into electricity at roughly 30%. Sending it through a turbine, a magnetron and back into the acid delivers about a fifth of the heat the exchanger delivers directly (0.30 × 0.65 ≈ 0.2), so on this site the microwave route needs roughly five times the primary steam energy of the baseline. Where microwaves do earn their place is not here but at the superphosphoric end (>70% P₂O₅, viscous, fouling, where the recent literature targets them), and an electric route for the 29-54 step should be compared against mechanical vapour recompression, which reuses the latent heat at a coefficient of performance of 10-30. Sweep the absorbed duty to see the product concentration and the electricity follow it. Model scope, stated up front. No property package in the tree can flash aqueous phosphoric acid honestly: the databank carries no heat capacity for H₃PO₄, NRTL has no binary and no UNIFAC groups for it, and the cubic equations of state give a boiling-point elevation of the wrong sign and an enthalpy flash that vaporised most of the feed from a 1 MW input. So this is the water-side model on IAPWS steam tables: the streams carry the acid's water only, and the 55.2 t/h of H₃PO₄ (40.0 t/h as P₂O₅) ride along as a non-volatile spectator in the mass balance the user variables compute. What that gets right is what the comparison turns on — the water removed and its latent heat, exact from IAPWS. What it leaves out, and by how much: the acid's own boiling-point elevation (tens of kelvin at 54% P₂O₅ — 85 wt% acid boils at 158 °C at atmospheric pressure — so the real acid runs 20-30 K hotter than these flash temperatures and the 320 K feed here stands in for a hotter plant feed), and the acid's sensible heat (of order 5% of the latent duty). Both move the temperatures, not the energy-carrier comparison. Microwave penetration depth (about a centimetre in a conductive acid at 2.45 GHz) and the HF attack on quartz windows are equipment questions this model does not carry.
Phosphoric acid concentration: microwave-then-steam hybrid (29 → 42 → 54% P2O5)
The transition path the concept proposes: microwaves take the acid from 29 to 42% P₂O₅ in a first vacuum flash (28.6 MW absorbed), a pump returns the 42% acid to atmospheric pressure, and the existing steam exchanger and second flash finish it to 54.0 wt% — 23.2 t/h of steam (0.58 t/t) plus 1,100 kWh of electricity per tonne of P₂O₅ at 65% magnetron efficiency, the same 64.0 t/h of water removed in total. The split is not free: two-thirds of the latent duty moved from a co-product steam to purchased electricity, and nothing about the second stage got easier. What a hybrid does buy is a pilot that can be run beside the existing evaporator without betting the line on it, and the freedom to put the microwave stage where it has a case — the viscous, fouling end — rather than on the dilute feed. Compare phosphoric-acid-concentration-steam and -microwave. Model scope, stated up front. No property package in the tree can flash aqueous phosphoric acid honestly: the databank carries no heat capacity for H₃PO₄, NRTL has no binary and no UNIFAC groups for it, and the cubic equations of state give a boiling-point elevation of the wrong sign and an enthalpy flash that vaporised most of the feed from a 1 MW input. So this is the water-side model on IAPWS steam tables: the streams carry the acid's water only, and the 55.2 t/h of H₃PO₄ (40.0 t/h as P₂O₅) ride along as a non-volatile spectator in the mass balance the user variables compute. What that gets right is what the comparison turns on — the water removed and its latent heat, exact from IAPWS. What it leaves out, and by how much: the acid's own boiling-point elevation (tens of kelvin at 54% P₂O₅ — 85 wt% acid boils at 158 °C at atmospheric pressure — so the real acid runs 20-30 K hotter than these flash temperatures and the 320 K feed here stands in for a hotter plant feed), and the acid's sensible heat (of order 5% of the latent duty). Both move the temperatures, not the energy-carrier comparison.
Corn wet milling: starch to high-fructose corn syrup
The sweetener train of a corn wet mill, end to end on the new sugar thermo package. A 35 wt% starch slurry off the mill is saccharified to glucose (glucoamylase, Michaelis-Menten), part-isomerised to fructose, enriched by simulated moving-bed chromatography, and concentrated to syrup in a two-effect evaporator. Three results are worth reading rather than assumed. The isomerase lands at 42% fructose — the real equilibrium of glucose isomerase, which is precisely why an SMB exists downstream: the reaction cannot reach HFCS-55 on its own. The SMB then splits on the cited Ca²⁺-resin affinities (fructose H=0.69 vs glucose H=0.26), sending fructose to the extract and recycling glucose in the raffinate. The evaporator finishes at 77 wt% solids, commercial HFCS syrup spec. That last number is only reachable because of boiling-point elevation. Modelled as inert solids the sugars give no BPE feedback and the evaporator is bimodal — it either does not boil or boils to dry sugar, with nothing in between. The sugar package (Norrish) supplies the real elevation, and syrup concentration becomes a smooth, controllable function of steam (42 → 77 wt% over the sweep range). Starch itself is carried as an involatile pseudo-component: it has no boiling point to characterise, so none is invented.
Aniline via nitrobenzene hydrogenation
Vapor-phase catalytic hydrogenation of nitrobenzene (C₆H₅NO₂ + 3H2 → C₆H₅NH₂ + 2H2O, highly exothermic) with excess hydrogen, a high-pressure flash recovering unreacted H₂ as a recycle vent, then a reduced-pressure flash stripping residual water from the crude aniline.
Steam utility island: deaerator, boiler, desuperheater
The three units that stand between raw makeup water and steam a turbine can accept, on the IAPWS steam tables. The deaerator takes 500 mol/s of 300 K makeup and 40 mol/s of LP steam and returns 540 mol/s of saturated liquid at 5 bar (425 K) for 3.23 MW. It is a direct-contact heater, so the heating steam does not leave — it condenses into the feedwater and shows up in the outlet flow. That is the point of the unit: the reason a plant heats feedwater by injecting steam into it rather than through a tube bundle is that boiling the water is what strips the dissolved oxygen out of it. The boiler then absorbs 26.6 MW into the water and fires 31.3 MW to do it — the gap is the stack loss, and it is the number a fuel bill is written against, not the absorbed duty. The desuperheater takes that 720 K steam down to a 660 K target by spraying 25.96 mol/s of water into it. The spray rate is SOLVED, not specified: you state the temperature you want and the unit finds the water that achieves it, which is how an attemperator is actually specified. Note the outlet is 566 mol/s, more than entered it, the spray water becomes steam. Bounded: the deaerator is an equilibrium model, so it reports no rate-based O₂/CO₂ stripping (there is no residual-oxygen ppb number here, which is what a real deaerator is guaranteed on), and the desuperheater assumes the spray fully evaporates.
Ethylene glycol plant: closed water loop + multi-effect evaporator dehydration
The water-integrated evolution of the fiber-grade MEG plant. Two changes turn the once-through EO/glycol chain into a real, water-economical process: (1) the recovered process water is RECYCLED back to the hydration reactors through a purge splitter. A pure recycle is inventory-singular (reactors are keyed on the shrinking EO pool, so water consumption is fixed regardless of how much water circulates), so an 8% purge pins the loop and makes it well-posed, cutting fresh water makeup from 10 to ~1.75 mol/s (a >80% reduction). (2) The bulk dehydration is done by a genuine TWO-EFFECT EVAPORATOR TRAIN (forward-feed, real steam economy: effect 1's low-temperature vapor is the heating steam for effect 2) doing rigorous (P,H)-flash water removal, rather than a single spec-based split. The recycle converges through the solver's Wegstein tearing (~15 outer passes) and MEG still comes out fiber-grade (>=99.9%). HONEST SCOPE: the reaction chemistry is rigorous stoichiometry (real atom balances, ~90/9/1 selectivity) and the evaporators are real energy-balanced flash effects — but flash evaporation CANNOT reach glycol dryness without slipping glycol into the overhead vapor (MEG has a real vapor pressure at 90 C), so the evaporators run cool and only pre-concentrate. An overhead knockout returns the ~1-2% slipped glycol to the product (no yield loss), and a final vacuum-refining polish (still a spec-based split, representing the refluxed dehydration column a flash cannot replicate) removes the last water. This mirrors a real MEG plant's multi-effect-evaporator + vacuum-refining dehydration section. The product columns remain spec-based (a converged 99.9% fiber-grade MEG column is not tractable under Peng-Robinson here — the MEG/DEG relative volatility is too narrow for the wide-boiling MESH path).