Cost of Steam Systems: Beyond Fuel Cost & Boiler Efficiency
by Taryn Hardes, on Tue, Jan 29, 2013 @ 09:01 AM
Fuel cost and boiler efficiency are key elements, but they tell less than half the story. For example, depending on the system, condensate may be getting to the tank through several different return systems at different pressures. Active management can lower costs considerably. Get tips below then learn about related services here:
What does a steam system cost? The specific answer will be a little different for each system. Fuel cost is an obvious factor. Operating steam pressure is another: The lower the pressure, the lower the cost. The percentage of make-up water will make a difference too. It has a lower Btu content than condensate return. Finally, there's the matter of boiler efficiency, which can vary with load demand and firing rate.
If you have the above information, you can make the simplest of calculations, called the unloaded steam cost. That's basically the amount of steam produced, and the cost of fuel required to produce it.
Let's start with the simplest kind of system: one boiler, a single type of fuel, and one operating pressure. In this example, we'll assume steam is being generated at 100 psig and is being returned to a deaerator tank operating at 10 psig. We'll peg the fuel cost at $9.50 per MMBtu, and the boiler efficiency at 85 percent. The unloaded steam cost, then, is $10.96 per 1,000 pounds.
If we don’t bring any condensate back and we use 100% make-up water, then we lose all the sensible energy that is in the condensate and we have to bring the make-up water up to the steam temperature before we can make steam at a given pressure. This extra energy we are putting in costs money. If we keep all the other variables the same, the cost of producing the same 1000 pounds of steam rises from $10.96 to $12.50, a difference of $1.54 per 1000 pounds. If our boiler is producing 50,000 lbs/hr the annual savings is over $600,000!
A wider look
An even more sophisticated calculation is to figure out the loaded cost of steam. In addition to the costs we've already considered, we add the cost of electricity, chemicals, water and sewer service, emissions payments, labour costs, waste disposal, maintenance and new projects. Once they are all factored in, the true cost of steam can easily come to twice as much as the unloaded steam cost.
It's a tough assignment to take on without any help. That's why Edmonton Valve is ready to help you (see below). Once you know the correct cost of steam, you can more accurately assign the true cost to various production areas for accountability, evaluate the economics of proposed improvement projects, and set a benchmark for optimizing the steam generation system.
Our experienced team is ready to help
Edmonton Valve invites you to take advantage of Swagelok Field Advisory Services. Getting started creates no cost or obligation.
Our local field service technicians have deep experience with fluid system applications for oil & gas, chem refining, power, midstream, and steam-assisted gravity drainage (SAGD) companies. They can address:
- Steam systems
- Analyzer sample conditioning systems
- Grab sampling systems
- Mechanical seal support systems for rotating equipment
- Gas distribution systems
- Instrumentation pigtails
- Point-of-use manifolding
- Manifolding for multiple gas cylinders
- Regulator changeover manifolds
- Purge panels
Need technical help right now? Call our 24x7 Field Advisory Services On-Call Technical Support: 780-237-7109. (For general support, please call 780.437.0640.)