Flash steam released from hot condensate can be recovered and applied elsewhere in the plant to maximise overall efficiency. Recovery systems reduce steam-raising costs, utility bills and CO2 emissions, and help achieve significant savings in fuel, water and feed-water chemicals. The return on investment is quick (around 3.4 years with the assumptions taken here). Jacketed vessels, flash-steam recovery vessels, and several other tools are available to operate flash steam recovery.

Some conditions need to be satisfied for successful flash-steam application:

The return of the condensate

Steam condensate is a well-known by-product of many industries. What is less well known is that it can be a powerful source of heat that can be reused.

Using this end-of-pipe steam to improve efficiency makes economic and environmental sense. A plant’s energy load and water consumption can also be cut by insulating pipework and preventing steam and condensate losses.

There are two main types of condensate recovery systems:

Economisers are gas-to-water heat exchangers located within a purpose-built flue section. They are used to recover heat from flue gasses for shell and water-tube boilers.

The main use of economisers is to pre-heat boiler feed water. An economiser can potentially be retro-fitted to most steam and high-temperature hot-water boilers, and there are also opportunities to fit economisers to conventional, non-condensing heating boilers.

On a daily or weekly basis, steam boilers blow down hot water from the boiler to avoid the formation of sludge.

Blowdown heat systems can recover much of this waste heat and reuse it. The system is made up of a flash vessel and a heat exchanger. It works best when blowdown is carried out continuously when boilers are operating over longer periods and levels of condensation recovery are relatively low.

Case for dual burners

Installation of dual fuel burners to replace heavy oil burners, with the aim of increasing fuel-heat effectiveness and avoiding radiation heat loss, among others.

Steam and high-temperature hot water (HTHW) boilers is a category of technologies commonly used in industrial sectors and in some applications in public and commercial organisations. HTHW boilers are very energy intensive and therefore offer many opportunities for energy and cost savings.

According to the Carbon Trust, heating can account for as much as 60 % of total energy use, yet a large proportion of the energy consumed by heating is likely to be wasted due to incorrect control settings. Notably, lowering heating temperatures by just 1º C can save 8 % on fuel consumption, and heating costs can increase by 15 % or more if boilers are poorly operated or maintained. Optimum heating systems can lead to significant cost savings

According to the Carbon Trust, heating can account for as much as 60 % of total energy use, yet a large proportion of the energy consumed by heating is likely to be wasted due to incorrect control settings. Notably, lowering heating temperatures by just 1º C can save 8 % on fuel consumption, and heating costs can increase by 15 % or more if boilers are poorly operated or maintained. Optimum heating systems can lead to significant cost savings.

Optimum start controls vary the times that heating systems come on, depending on the weather, occupancy, and the current heat in the building. Using optimum start instead of fixed time control can save up to 10 % in energy costs. 

An optimum start controller costs between € 90 (£ 80) and € 340 (£ 300), which means investment costs could be recuperated in less than five years.

Large, centralised, hot-water systems can often be inefficient. At times when demand for hot water decreases, a large system can waste energy and money. Equally, with decentralised systems it is likely that heat is being lost from long pipe runs. Installing individual heaters closer to where the hot water is needed can lead to significant savings.

Two main types of decentralised hot-water systems:

High-efficiency or condensing boilers reduce utility bills and increase energy efficiency compared to ageing boiler units. They are also smaller and lighter than traditional boilers.

Condensing boilers can be controlled via a thermostat and achieve savings between 10 % and 30 %.