Most plants that discharge low-pressure exhaust steam pay twice for the same heat: once in fuel to make it, and again in purchased steam to replace the pressure it lost. A steam booster heat pump closes the second payment. It takes the low-grade steam, compresses it, and returns it to the process header as higher-pressure saturated steam, so the recovered heat does useful work at the temperature the process actually needs. MOON-TECH’s steam booster series — a 2018 China International Refrigeration Exhibition Innovation Product Award winner — is built for exactly this loop.
The decision to add one is arithmetic, not preference, and it comes down to a small number of checks you can run on your own site data.
Two machines, two answers
The first way to lift steam pressure is the ejector: a jet of high-pressure steam entrains and compresses the low-pressure steam, with no moving parts at all. It is simple and robust, but the motive steam is itself high-grade, so the machine spends part of the expensive steam to recover cheaper steam. The net saving is real, and it shrinks as the required outlet pressure rises.
The second is the compression heat pump: an electric compressor raises the pressure of the waste steam, the steam condenses at that higher pressure, and the heat of condensation — the original heat of the waste steam plus the heat of compression — leaves as high-grade saturated steam. Because the electrical input is added to the recovered heat rather than replacing it, the steam output can exceed what the same electrical energy would buy from a boiler. That is the structural reason the compression route is the stronger recovery tool where the pressure lift is significant.
How the cycle runs
The loop is short. Waste or exhaust steam is compressed to the target header pressure; at that pressure it condenses, releasing its heat plus the compression heat, and the resulting steam — high-grade and saturated — returns to the process. The condensate is pumped back to the boiler feed or the recovery point, closing the water loop as well as the heat loop. Nothing in the sequence is exotic: it is the same compression–condensation cycle as a refrigerator, run on steam and in the direction that pays.
The published function of MOON-TECH’s series is exactly this: recover waste and exhaust steam, upgrade the steam grade through the compressor, and deliver high-grade saturated steam back to the plant, for sectors that require high-temperature, high-pressure steam.
Five checks before you size it
- Available steam, honestly stated. Flow, pressure and temperature of the waste stream across the plant’s real load swings — not the peak number on a datasheet. A booster sized for a flow that exists two hours a week will look like a failure in its first quarter.
- The pressure lift. The gap between the waste steam pressure and the target header pressure sets the compression ratio and the electrical cost per tonne of recovered steam. A wide lift is still often profitable, but the arithmetic changes.
- Feedwater in a closed loop. When the condensate returns to the boiler, dissolved solids concentrate with each cycle. Confirm the bleed and treatment strategy before the loop is closed — it is the check most often discovered after commissioning.
- Return lines and traps. Condensation in long return lines, trap sizing, and the interaction with the existing header’s pressure control must be designed together, or the header meets a new variable it was not tuned for.
- Electrical. Compressor motor size and start type, checked against what the saved steam is worth on your tariff.
Where it fits
The target application is stated plainly: sectors that require high-temperature, high-pressure steam and discharge recoverable waste or exhaust steam — chemical, food and process plants are the classic cases. The unit does not replace the boiler. It makes sure the steam the plant already generated is not the steam the plant has to buy back.
Questions plant managers ask
What is the difference between a steam ejector and a steam booster heat pump?
An ejector uses high-pressure steam as its working fluid — no moving parts, but it spends part of the expensive steam to recover cheaper steam. A heat pump uses an electric compressor and adds the compression heat to the recovered heat, so the steam output can exceed the electrical input as energy. Where the pressure lift is large, the compression route is usually the stronger recovery tool.
How much waste steam is enough to justify a booster?
There is no universal threshold. It follows the pressure differential, the flow, how many hours a year that flow exists, and the price of the steam being replaced. Build the heat balance for the plant’s real operating hours — continuous moderate recovery beats a small flow at peak — and the payback becomes arithmetic rather than judgement.
What does the booster deliver, and will our processes accept it?
High-grade saturated steam at the target header pressure. The check is on the receiving side: confirm the downstream processes accept saturated rather than superheated steam, that the target pressure matches the header, and that the flow works with the header’s existing pressure regulation.
Have a steam balance for your site?
Send the waste steam pressure and flow, the target header pressure and the hours of operation. The engineering team responds with the expected recovered steam and the electrical load.