The Science of Thermocompression Explained

Most plants still reduce steam pressure with a valve & dump flash steam through traps or vents. That’s simple—but wasteful. The idea behind thermocompression is even simpler: don’t throttle—recycle. Use a small amount of high-pressure steam to pull in low-pressure vapor/flash & re-pressurize it back to a useful level. The result is steadier heating systems, better heat transfer, & saving energy—often in the double-digits

Thermocompressor

What is Thermocompression?

Thermocompression uses a jet device—to mix two steam streams of different pressures:

• Motive steam (from the boiler header) at higher pressure.

• Suction steam at lower pressure (typically flash steam from steam condensate, vapor from a process vessel, or return from a dryer/heat user).

Inside the ejector, the motive jet entrains the low-pressure vapor & the pair exits as mixed steam at an intermediate, controlled pressure useful to the process. This is the core steam jet ejector working principle—& it’s the reason a Jetomat can act like a compact, robust vapor compressor with no moving parts.

Components of a Jetomat System

OPERATING MODES

1. Recirculation / Back-mixing mode

• Goal: improve heat transfer by raising internal steam velocity & sweeping condensate films.

• Benefit: faster warm-up, more uniform surface temperature, better dryer/heat-exchanger performance.

2. Compression mode

• Goal: act as a heat recovery system—capture low-pressure flash/vapor & re-pressurize it to the user setpoint.

• Benefit: displaces fresh boiler steam, enabling substantial saving energy & reducing make-up water & treatment chemicals.

HOW IT WORKS

Jetomat Working

1. Motive steam acceleration
   High-pressure flows across the Variable motive nozzle, trading pressure for velocity. Think of this as creating a high-speed jet.

2. Entrainment of suction vapor
   That jet lowers static pressure in the suction chamber, pulling in low-pressure flash steam (& any compatible vapor). This is the “recycling” step.

3. Mixing & momentum transfer
   In the mixing section, the fast jet shares momentum with the suction vapor. Energetically, a portion of the motive steam’s exergy is transferred to the low-pressure vapor.

4. Pressure recovery in the diffuser
   The diffuser slows the mixed flow, converting velocity back into pressure to your setpoint. That mixed steam goes to the user—dryers, coils, calenders, reboilers—as a controlled supply.

KEY PERFORMACE TERMS

• Entrainment ratio (ω) = suction flow / motive flow.

• Compression ratio = (mixed-steam pressure)/(suction pressure).

• Turndown = controllable operating range via motive-steam valve position.

SYSTEM ACCESSORIES

• Instrumentation & control: Pneumatic or Electric Actuator For Variable Nozzle, mixed-pressure PID / PLC controller, temperature feedback, flow/pressure transmitters.

• Piping good practices: strainers on motive line, short suction runs, gentle reducers to avoid pressure drop.

• Condensate handling: many thermocompressor layouts simplify or remove trap banks by forming a condensate & flash steam recovery system.

• Steam separator / flash vessel (as needed): depends on site standards; often reduced or streamlined because the ejector itself is the flash steam recovery system.

Benefits & Applications

1) Energy, Throughput, & Quality

• Recover instead of venting: the Jetomat’s thermo compressor working principle reuses flash steam that PRVs & traps usually waste. Plants frequently document 10–30% steam reductions in compression service.

• Better heat transfer solutions: higher internal steam velocity thins the condensate film, raising effective surface temperature & improving uniformity. Many users see faster warm-up & higher line speeds.

• Stable conditions: the mixed-steam pressure is controlled; fewer hot/cold spots, less cycling, & more consistent product quality.

2) Less Hardware, Fewer Headaches

• Simplified loops: a well-designed thermocompressor design can replace PRVs + multiple traps + vent lines. In some dryer sections, trap counts drop drastically or disappear.

3) Where It Fits in the Process Industries

• Dryers / cylinders / can-dryers (paper, textile): raise velocity, sweep condensate, reclaim return steam.

• Evaporators / concentrators (food & beverage, chemicals): recompress secondary vapor

• Reboilers, cookers, sterilizers: recycle overhead vapor to reduce fresh steam draw.

• General steam equipment retrofit: anywhere a PRV drops pressure & a vent or trap wastes vapor.

4) Typical Numbers (What to Expect)

• Energy: double-digit % steam savings are common where flash losses exist.

• Water/chemicals: reduced make-up & dosing by keeping steam & condensate in the circuit.

• Maintenance: fewer traps & valves to survey; the ejector itself is largely maintenance-light.

Jetomat

Practical Design Notes

• Data first: collect motive header pressure/temperature, suction source pressure, current vent/flash locations, target mixed pressure/temperature, & expected load swings.

• Right-size the ejector: match thermocompressor design to real operating points; avoid chronic blow-off or starving.

• Control philosophy: most plants regulate by mixed-steam pressure; others use temperature (e.g., drum shell or condensate outlet).

• Layout details: short, open suction; avoid long, restrictive runs. Install strainers on motive line. Provide proper condensate drainage.

• Integration: the Jetomat drops in ahead of the user, replacing PRVs. Existing DCS/PLC handles the motive-valve loop; no special black-box control required.

Conclusion

Thermocompression is simply smarter steam use. A Jetomat steam jet ejector functions like a durable steam compressor built from a diffuser & nozzle—using momentum, not moving parts—to recycle flash steam & stabilize your heating systems. The results are predictable: saving energy, cleaner loops with fewer traps, & better heat transfer.

What to do next

1. Screen your sites: where do you throttle with a PRV & see vent plumes or heavy trap maintenance?

2. Quantify: build a quick mass/energy balance on motive vs suction flows; size a steam jet thermocompressor to your target mixed pressure.

3. Pilot & prove: convert one throttled user (dryer, evaporator, reboiler), measure steam, temperature stability, & product KPIs.

4. Scale up: standardize the design across similar units to lock in plant-wide benefits.

If you’d like help with a quick steam recovery system review—or to see how a Jetomat could fit your loop—reach out for a no-obligation assessment. We’ll map the thermo compressor working principle to your process & deliver a practical, Measurable plan to modernize your steam network.