Efficient steam and condensate management is not just vital for manufacturing plants – it can have a direct impact on the cold chain and refrigeration sectors. By recovering high-quality condensate and harnessing waste heat, cold storage operators can reduce energy consumption, lower operating costs and improve system reliability. Optimised condensate return also supports sustainable operations by reducing water usage and ensuring more consistent temperature control in cold chain processes.
Strong partnerships with thermal energy users optimise opportunities to benefit from condensate return (CR), waste heat recovery and the prevention of system contamination says steam and boiler operations and maintenance service provider, Associated Energy Services (AES) Commercial Director, Dennis Williams.
Condensate return
“Steam quality is the responsibility of AES on sites it manages, and this includes protecting the boiler assets and the quality of steam supply, to ensure optimised plant and boiler operations.
Although facilitating condensate return is officially outside AES’s remit, Williams says the company often provides its own and specialist third party insights: “Our limit is receipt of condensate at the hotwell in the boiler house. The client must manage the collection and return of condensate because this is integral to the use of steam – and should be controlled by production personnel as it impacts on plant operation,” he advises.
The client’s steam usage system determines both the quality and amount of condensate available. If steam is used via direct injection, no condensate can be recovered. If steam is an indirect heat source (in coils or heating jackets), then condensate can be extracted.
Key factors such as conductivity, hardness and temperature all determine quality, Williams explains: “Total Dissolved Solids (TDS) and hardness stem from the contamination of steam / condensate circuits in the client’s facility, such as leaking heat exchangers or coils. This results in product ingress into the steam / condensate circuit. It can also come from heating and cooling plenums, where there is no rinse cycle after the cooling cycle. Condensate is then contaminated with cooling water that is high in TDS and hardness.”
The higher return rates of hot, high-quality condensate assist in optimising steam generation as follows:
- All sensible heat (temperature) returned saves on fuel inputs – as the energy input is related to the difference between the condensate temperature and the steam temperature (including phase change energy). More heat returned means less fuel used.
- The higher percentage of CR requires less make-up water to account for the CR losses – as well as the use of less fuel to heat the make-up water from ambient temperature to boiler steam temperature (including phase change energy).
- A higher percentage of CR also means lower TDS compared to make-up water, and therefore less blow-down to maintain boiler TDS, less fuel input energy, less water costs and less water treatment.
However, if TDS is out of specification, the condensate cannot be used and must be dumped, as it will foul the boiler heat exchange surfaces, cause higher fuel usage and potentially damage the boiler pressure part, Williams warns.
Source: Supplied by AES, edited by Eamonn Ryan