The capabilities and properties of steam make it ideal for use in many industrial processes. Industries use steam for generating power and as a method of delivering heat. Steam is also used to produce food, paper, brewing, chemicals, textiles, rubber and many other items. Steam is an excellent energy source for several reasons, including being less expensive than alternatives and non-toxic.
This guide to steam for industrial processes will dive into the history of steam, types of steam for heating applications and the benefits of steam.
History of Steam for Industrial Operations
Pioneers were using steam before the Industrial Revolution. Historians trace the earliest steam engines to the first century C.E., but these simple spinning engines called aeolipiles were more novelties than practical devices.
It was only in the late 18th century that steam-powered inventions quickly found their way into various industrial settings — steam pumps for extracting water from mines, steam engine trains, and steam for powering boats, farms and semi-automated factories. Thanks to the advent of steam, new markets were expanded, improving the economy, infrastructure and quality of life.
Today, we still use steam for generating power, whether we use coal, gas, nuclear or geothermal energy as fuel.
How Is Steam Produced?
Steam is typically created using boilers, but modern technology also allows manufacturers to produce steam using solar energy. Steam boilers create pressurized steam by using a fuel source, like burning coal, to heat water to its boiling point. There are two main kinds of boilers — firetube boilers and watertube boilers.
In firetube boilers, tubes containing a combustible fuel source heat a surrounding vessel of water until the water is hot enough to convert to steam. In watertube boilers, there are multiple metal tubes filled with water inside the boiler, and a combustible fuel source heats the pipes from the outside until they create steam.
In today’s applications, manufacturers prefer watertube boilers because they’re safer. Watertube boilers can also produce more pressure than firetube boilers, making them more efficient.
What Are the Types of Steam for Process Heating Applications?
Not all steam is the same — several different types of steam for processing heating applications exist.
Wet Steam
Unsaturated steam is the result when a boiler heats up and water bubbles break through the surface. The vapor contains liquid when it’s formed. Even using the best boilers, there will be some water molecules that aren’t vaporized in the process, making the steam “wet.” The non-vaporized molecules remain as water droplets or mist.
Dry Steam
Dry or saturated steam results from heating water so that all its molecules remain in a gaseous state. Dry steam is produced by heating water in a closed chamber to its boiling point and then vaporizing it with additional heat through a process called latent heating. Dry steam occurs when the rates of water vaporization and condensation are equal.
Dry steam is an excellent heat source for several reasons:
- Quick and even heating means better quality and productivity of applications.
- Dry steam requires a smaller heat surface because it absorbs more latent heat.
- Because dry steam contains as little as 5% moisture, it is safer to use electric controls and other equipment that shouldn’t come into contact with water during processes.
- Dry steam is safe around a wide variety of chemicals, though you should always verify which chemicals the process uses and if interaction with steam is safe.
Superheated Steam
Superheated steam is steam that’s at a higher temperature than the boiling point, or vaporization point, of the liquid under a given pressure. You get superheated steam by applying additional heat to dry steam. At this point, most, if not all, moisture is eliminated.
Superheated steam is thermodynamically efficient. Though superheated steam is hotter and more energetic than dry steam, and though it is used widely in power generation plants, it does not fit every application.
Other types of steam — which are forms of dry or superheated steam — include:
- Culinary steam: As the name suggests, culinary steam is used in food processes, either to sterilize contact surfaces or to add directly to products. Culinary steam contains FDA- or USDA-approved additives that prevent corrosion in boilers. The additives are then filtered out before the steam comes into contact with food.
- Plant steam: Manufacturers typically use plant or utility steam for processes like indirect heating.
- Pure steam: Pure steam, also called clean or hygienic steam, does not contain additives, making it safe to use for processes that must meet organic food standards.
How Is Steam Used in Industrial Processes?
Steam, specifically superheated steam, has various industrial applications:
- Power generation: Steam is an excellent resource for generating power. Steam turbines convert steam’s heat energy into mechanical energy. This power source is often used in nuclear power plants.
- Sterilization and disinfection: Steam can be used for sterilization and disinfection in medical applications.
- Processing applications: Manufacturers can use steam for processes that involve cleaning, drying, layering and curing. Steam also has applications in chemical reactions and catalysis.
- Soil steaming: Soil steaming is a farming technique that uses steam to sterilize soil. The hot steam kills a host of weeds, fungi, bacteria and viruses in the ground.
Benefits of Steam as an Energy Source
Using steam as an energy source is advantageous for several reasons:
- The fuel that manufacturers need for steam power plants is more cost-effective.
- Manufacturers can use a variety of fuel sources for steam power plants.
- Steam power plants require less space compared to other manufacturing plants.
- There is less waste as some steam can be recycled as process steam for different applications.
- The initial costs of steam power plants can be less than those of diesel power plants.
- Steam plants are efficient as they convert a good amount of fuel energy into electric or mechanical energy.
- Steam power plants respond quickly to changes in an electrical grid’s demand. Efficient grid support also means greater stability.
Contact MSEC for Industrial Services and Products
MSEC, Inc. is a distributor and service provider of industrial process equipment, including valves, valve automation, actuators, heat transfer, steam specialties and instrumentation. MSEC works with some of the world’s leading manufacturers and distributors to provide processing and equipment solutions for industrial facilities. Since 1978, we have partnered with customers to optimize their processes and implement solutions that drive efficiency.
Our full-service company offers clients throughout the western United States a broad range of products and resources, including design, application, commissioning and product startup services. Contact MSEC today to request a free quote, or call us at 303-232-4100 to speak to our knowledgeable and experienced team.