What the application demands
| Requirement | What it means in the design |
|---|---|
| Recovery and corrosion must be calculated together | Chasing recovery efficiency without checking dew point corrosion can scrap the unit within one or two years. |
| Dust causes fouling | Dust bridges the fin passages, reducing heat transfer and raising pressure drop. |
| Retrofit space is limited | Adding a unit to an existing system is constrained by site space and flue gas pressure drop. |
| Recovered heat must be used | The hot water or hot air must have a stable use, otherwise the payback does not exist. |
Our approach
We first calculate flue gas flow, inlet and outlet temperature and recoverable heat, then set the output parameters of the recovery medium. Next we check the cold-end wall temperature against the acid dew point and set fin spacing and cleaning method against dust loading. A payback estimate is provided for the project decision.
- Flue gas to water: hot water for process or domestic use
- Flue gas to air: hot air for drying or combustion air
- Wider fin spacing or H-fin with soot blowing for dust-laden gas
- Retrofit projects checked for flue gas pressure drop and available space
Design highlights
- Cold-end wall temperature checked before surface area is fixed
- Materials selected against acid dew point corrosion and dust loading
- Recovery scheme matched to the actual use of the recovered heat
- Payback estimate based on year-round load rather than nameplate rating
Project status
Recovery schemes are selected after the heat balance, corrosion check and site constraints are confirmed. We support both new projects and retrofits of existing systems.
Common waste heat recovery scenarios
| Heat source | Flue gas characteristics | Recommended recovery |
|---|---|---|
| Industrial boiler | Contains sulphur; condensation possible | Flue gas to water; check cold-end wall temperature |
| Industrial kiln | High temperature and dust | Flue gas to air; wide fin spacing or H-fin |
| Drying furnace | Medium temperature and high moisture | Flue gas to air for drying reuse |
| Metallurgy and building materials | High temperature and heavy dust | Cool with a flue gas cooler, then recover |
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FAQ
Is a retrofit worth doing?
It depends on flue gas flow, recoverable heat and energy price. We can estimate the payback before the project proceeds.
Will a retrofit interrupt production?
The flue gas pressure drop and site space have to be checked. Installation is normally scheduled during a maintenance shutdown.
Can sulphur-bearing flue gas be used?
Yes, but the dew point corrosion must be checked and the finned tube material selected accordingly. Otherwise service life will be short.