Steam is used in many industrial processes and is often a source of large amounts of wasted energy and money. Making energy savings is easy. It is crucial to establish a regular maintenance program to inspect and repair steam traps, steam leaks and insulation. By insulating steam distribution and condensate return lines, savings are made because less heat is lost to the surrounding air, thus minimising costly steam production. It is also important to consider the use of steam and whether it is necessary for all applications, or whether other energy sources, such as gas, could be used. Improving your boiler efficiency is another way to make savings on your steam system, but is not addressed in this section. Taking Action 1.Are there steam losses in your system? > Info Steam leaks Actively identifying and repairing steam leaks can achieve steam system efficiency improvements of 3-5%. As well as wasting energy, leaks cause a drop in system pressure that can cause equipment to operate less efficiently by reducing the amount of heat that can be delivered to a process. Fixing leaks may involve anything from simply tightening a connection to replacing faulty fittings.

Industrial facilities can reduce steam energy consumption by 20% through simple improvements in their steam system.

Steam trap leaks

Steam traps allow the condensed steam to be removed from the steam distribution system.

• It is common to find that steam distribution systems go without maintenance for three to five years.
• Without adequate maintenance, 15-30 % of a plant’s steam traps are often inoperable.
• Steam traps fail in the open position, which means steam passes through the condensate system and is wasted.
• Energy efficiency gains of 10-15 % are common when steam traps are actively maintained, so establishing a regular maintenance program, including complete systematic inspection, testing and repairing of steam traps is imperative.

>Action

Finding Leaks

• Steam leaks are easily identified visually and should be tagged when located.
• Use an ultrasonic detector to locate leaks. They cost about $1300, but the cost of a detector will be repaid by the savings from fixing just one leak as an average steam leak costs around $3500 per year.
• A monitoring system consisting of small control attachments to individual steam traps can be connected to a hand held computer or linked to an Energy Management System so the user can check the effectiveness of the steam traps themselves.

Steps to calculate how much steam leaks are costing:

1. Locate steam leaks.
2. Identify the diameter of the leaks.
3. Determine the mass of steam lost per hour from the table below. Do this by counting the number of leaks of each size then, knowing the pressure of the steam, the steam loss can be calculated.
   
   
   
   
4. Multiply this mass by the yearly operating hours.
5. Multiply this by the value of steam per tonne. This value is dependent on many variables and it is important to get advice on this. As a general rule, steam can cost $18/tonne, which includes the cost of gas to heat boiler water, chemical treatment of the water and other costs.
   For example: a trap of 4.5mm is found to be stuck open on a 1035kPa steam line.
   By repairing the failed trap, the savings can be calculated:
   
   

2.Can heat losses be reduced?

> Info

Insulation

Insulation around pipes and valves dramatically reduces heat loss and makes the work environment much safer by reducing the likelihood of severe scalding. It can typically reduce energy losses by 90% and help ensure proper steam pressure at plant equipment. The higher the temperature of the boiler skin or pipes, the greater the radiant heat loss to the surroundings.

Minimise pipe lengths

Often a sequence of plant upgrades leads to unnecessarily long lengths of steam pipe, which increases the heat loss. Reducing pipe length makes good financial sense. Also, where a small steam load is located at the end of a long branch of steam pipe, it might be cost-effective to install a stand-alone piece of equipment, and to decommission that section of the steam system.

>Action

Install insulation

• To measure the temperature of your pipes, use an infrared thermal sensor meter. They cost $600-$800 but this outlay can be repaid by the savings from insulating your system. It is also advisable to consult a supplier of steam system monitoring equipment and they will often test your steam distribution system for free as part of a quote for work.
• Any surface about 10ºC above ambient temperature should be insulated, including boiler surfaces, steam and condensate piping and fittings. Removable insulating jackets are available for valves, pressure-reducing valves, steam traps and other fittings.
• Damaged, missing or wet insulation should be repaired or replaced regularly. It is important to consult an expert on steam system insulation because the thickness and type of insulation material varies according to pipe size and application.

The following example will give you an idea of the money that can be saved by insulating pipes. For example: If a 75mm bare pipe transported steam at a temperature of 150ºC above ambient temperature, 640 Watts of power would be lost per metre of pipe. By insulating this pipe, the loss could be reduced to 64 Watts, a 90% saving.