A 6C rise in boiler feed water temperature can lead to a 1% saving in fuel

With the ever-rising costs of energy and pressure on plants to reduce their carbon emissions, it has never been so important to return your condensate efficiently and effectively. It can be a very simple exercise and quite often because of this, its impor

With the ever-rising costs of energy and pressure on plants to reduce their carbon emissions, it has never been so important to return your condensate efficiently and effectively. It can be a very simple exercise and quite often because of this, its importance in overall efficiency can be overlooked.

After all condensate is hot pure water, meaning it is already carrying latent energy that requires less fuel to heat to the saturation temperature in the boiler and because it is pure means it doesn’t need to be chemically treated either. The more you return the more you save on fuel, chemical treatment, raw water and effluent costs.

When the backpressure becomes greater than the steam pressure, which is a frequent occurrence in most processes, the simplest way of returning your condensate back to the boiler feed tank is by a condensate pumping set. These can be steam driven or electrically operated pumps and are usually fitted with an atmospheric receiver. They operate by a float switching mechanism if steam driven or if electric a level sensor that engages the pump to pump the returning condensate away and back to the boiler feed tank.

One drawback of atmospheric receivers can be the loss of flash steam through the receiver vent. In lower pressure and temperature systems, this is not so much of a problem due to the relatively small amount of flash steam that is formed. However, in higher temperature systems the flash that occurs when condensate above 100°C enters atmospheric conditions and releases its excess temperature as flash steam through the receiver vent can represent a large percentage of energy being wasted to atmosphere. It is also not environmentally conscious to have flash steam in large quantities being vented to atmosphere.

Fear not, there are ways to recover this energy and overcome this unsightly release of flash steam.

In systems where you might have a higher condensate temperature, which therefore leads to a greater creation of flash steam when atmospheric conditions are introduced, ISIS Steam have just the answer.

The Valsteam Adca Flash Steam Heat Recovery Unit (FRECO) is a skid mounted package unit that facilities heat recovery from flash steam, condensate or both.

The FRECO, especially recommended for heating a continuous flow of liquid, is ideal to raise the temperature of the make-up water to a steam boiler well above 100°C

It is already known that the condensate return and its recovery ensures the best energy efficiency however the condensate which is initially at high temperatures ends up flashing and losing most of its energy when introduced to atmospheric conditions. On the other hand, feed water temperatures higher than 90°C to the boiler feed pumps when coming from atmospheric vessels will normally cause cavitation to the pumps leading to pump damage and premature failure.

The Valsteam Adca FRECO system prevents this problem since it is installed downstream of the boiler feed pumps. This means that the boiler feed water can be heated to well above 100°C before entering the boiler.

This ensures that the energy from the high temperature condensate that would normally flash off to atmosphere in the condensate pumps receiver or boiler feed tank is being utilised and large plumes of flash steam are no longer present.

It is determined that a 6°C rise in boiler feed water temperature can lead to a 1% saving in fuel.

Contact ISIS Steam, the Valsteam Adca partner to discuss your steam and condensate system and ensure that it is operating as efficiently as possible.

 

sales@isissteam.com

01608 645755

 

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