Recovering Condensate and Flash Steam to Save Energy

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In 2013, a study was conducted in India. The research article, aptly titled “Impact of Condensate Recovery on Boiler Fuel Consumption in Textile Sector” was published in the International Journal of Engineering Research and Applications, which is a peer-reviewed online open access journal that publishes research.

The scholars carried out case studies on multiple textile plants aiming to find the practicality of using “waste” flash steam in order to be more energy efficient and thereby cost effective. In simple terms, when electricity is generated, the process creates steam. This steam is often wasted, but is theorized to contain up to half of the condensate’s energy. As such, in order to be efficient in terms of not wasting any energy, it is important that industries make use of flash steam to further generate electricity.

Within the area studied, about 56 units of textile processing are located. 70% of these are both printing and dyeing facilities, while the rest are only dyeing facilities. These units make use of both thermal energy as well as electricity. The former is generated using imported coal, lignite coal, and natural gas, all of which are available readily. Imported coal and lignite coal are the main components of boiler fuel, used for steam generation.

There are two main ways that generation of energy can be more efficient in the textile sector. These are recovering condensate, and recovering flash steam. The processes for these are unique in their own way, but the larger picture provides efficient ways to improve. For every 6°C rise in the temperature of the feed-water of the boiler, fuel consumption decreases by approximately 1%. Returning condensate also reduces the cost of water and water treatment, as well as the load of pollution. Flash steam, on the other hand, refers to the condensate that turns into steam when pressure drops. When pressure goes from high to low, condensate re-evaporates, turning into steam instantaneously. This is where it gets its name.

The study discovered that approximately 5.9% of the fuel is wasted due to loss of condensate. While this number may not seem like a lot, it translates to the wastage of nearly 40 T of coal. In order to save this fuel and avoid it being wasted, it is important that condensate must be utilised, and heat must be recovered. Experiences have proven that this process is not expensive, and the initial investment can be easily recovered through the cost savings that will come about once condensate is no longer wasted.