Valve Magazine - Winter 2009

STEAM, THE ENERGY FLUID

a far cry from what was used in steam engines on trains or during the Industrial Revolution. Indeed, steam is the preferred choice for much of industry today. Name any well-known consumer brand, and in nine cases out of 10, steam will have played an important part in its production.

Figure 4. A modern boiler house package

time is required for the manual monitoring associated with oil or water systems.

In addition, when a steam system requires maintenance, the part that needs maintaining is easy to isolate and the system can drain rapidly, meaning repairs may be carried out quickly.

It has been shown in numerous

instances that it is far less expensive to bring a long-established steam plant up to date with sophisticated control and monitoring systems than it would be to replace the steam with an alternative method of energy provision, such as a decentralized gas system.

Today’s state-of-the-art technology is

Table 2. The benefits of steam

Inherent benefits • Water is readily available • Water is inexpensive • Steam is clean and pure • Steam is inherently safe • Steam has a high heat content

• Steam is easy to control due to the pressure/temperature relationship

• Steam gives us its heat at a constant temperature

System benefits

• Small bore pipework, compact size and less weight

• No pumps, no balancing

• Two-port valves, cheaper

• Maintenance costs lower than for dispersed plant

• Capital costs lower than for dispersed plant

• SCADA-compatible products

• Low noise

• Reduced plant size (as opposed to water)

• Longevity of equipment

• Boilers enjoy flexible fuel choice and tariff

• Systems are flexible and easy to add to

AND IT’S FLEXIBLE

Steam is not only an excellent carrier of heat, it is also sterile. Because of this, steam is popular for processes used in the food, pharmaceutical and health industries. It is also widely used in hospitals.

The industries where steam is used range from huge oil and petrochemical plants to small local laundries and range from production of paper, textiles, brewing and food, to curing rubber, heating and humidification of buildings.

Many companies find it convenient to use steam as the working fluid for both space heating and for process applications. For example, in the brewing industry, steam is used during different stages of the process, from direct injection to coil heating.

Steam is also intrinsically safe—it cannot cause sparks and presents no fire risk. Because of this many petrochemical plants use steam fire-extinguishing systems, and steam is ideal for use in hazardous areas or explosive atmospheres.