How is steam efficiently used?

While steam is the most efficient way of distributing and transferring heat energy, the equipment used must be designed and maintained properly to realize the benefits of that efficiency.

07/02/2013


According to the U.S. Dept. of Energy (DOE), over 45% of all the fuel burned by U.S. manufacturers is used to produce steam. This statistic may sound high, but steam is used to heat raw materials, cook and condition foods and beverages, treat semi-finished products, process oils and chemicals, and even extract oil from the ground. It is also a power source for equipment, as well as for building heat and electricity generation. But steam, and the water it’s made from, is not free. It costs more than $20 billion annually to feed the boilers generating the steam.

So, doesn’t it make sense to make that steam and use it as efficiently as possible?

While steam is the most efficient way of distributing and transferring heat energy, the equipment used must be designed and maintained properly to realize the benefits of that efficiency. The problem is, very few steam users know how efficiently their boilers are running, let alone the efficiency of the steam system installed in their entire plant.

To increase a steam system’s efficiency, the DOE recommends that users:

  1. Determine the efficiency of their steam generation system, based on steam output/fuel input
  2. Determine how much steam they use and how much it costs to generate this steam
  3. Optimize excess air in their boiler to increase steam generation efficiency
  4. Maintain clean fire-side and water-side boiler heat transfer surfaces
  5. Optimize boiler blowdown to reduce total dissolved solids (TDS) in the boiler system
  6. Optimize their boiler control system to optimize steam generation efficiency
  7. Ensure that an effective water treatment system is in place.

While items No. 3 through No. 7 are tackled to some degree in most boiler houses, many do not have real-time data for actual efficiencies or how much it really costs to produce the steam. Conversely, because this data isn’t available, plants are unaware of the money that could be saved by implementing a few changes to their steam systems.

The benefits of monitoring boiler and steam system efficiencies

In the U.S., most plant boilers operate with a fuel-to-steam efficiency of 75% to 85%. This results from stack losses, poor controls and set-up, blowdown losses, losses due to radiation of heat from the boiler, and poor heat transfer due to scaling. The rest of the steam system can then lose up to an additional 30% of energy due to insulation losses, steam leaks, blowing steam traps, flash steam losses, and lack of heat recovery from condensate. Many of these losses can be easily fixed once you know the problem exists. This is where a boiler and steam system efficiency monitoring system can help.

  • It will provide percentage figures for fuel-to-steam efficiencies for each boiler, with being data logged over time. This can immediately flag opportunities to improve boiler performance. For example, it’s possible to see the immediate effects of adding an economizer or changing from manual to automated TDS blowdown control. It allows boilers in a plant to be compared with each other and predicted efficiency figures from manufacturers. It also flags new problems with the boiler. Perhaps blowdown was missed or there’s a problem with the deaerator tank because the feedwater temperature has dropped resulting in a drop in the measured efficiency.

  • It will provide the steam system efficiency for the entire plant which can also be data logged over time. This allows a comparison to be made against industry benchmarks and between plants. For example, let’s say there are two identical plants, Plant A and Plant B. Their system efficiency figures differ greatly: Plant A’s efficiency is 20% higher than Plant B because at Plant A they have just fixed all of their leaking traps—a 7% efficiency improvement—and started recovering heat from all of their blowdown and flash steam—a 13% efficiency improvement.

  • It will provide the cost of producing steam for each boiler and for the plant. Of course, once you know the cost of the steam produced you can estimate the losses you may have when compared to other boilers, plants and benchmarks. This data can then easily be used to help justify system improvements to reduce overall costs.

Courtesy: Spirax Sarco

Content provided by Spirax Sarco, originally published in Steam News Magazine.



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
July/Aug
GAMS preview, 2018 Mid-Year Report, EAM and Safety
June 2018
2018 Lubrication Guide, Motor and maintenance management, Control system migration
May 2018
Electrical standards, robots and Lean manufacturing, and how an aluminum packaging plant is helping community growth.
April 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
August 2018
SCADA standardization, capital expenditures, data-driven drilling and execution
June 2018
Machine learning, produced water benefits, programming cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
August 2018
Choosing an automation controller, Lean manufacturing
February 2018
Setting internal automation standards

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Material Handling
This digital report explains how everything from conveyors and robots to automatic picking systems and digital orders have evolved to keep pace with the speed of change in the supply chain.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me