Level Instrumentation for Steam Generation

Steam is today’s utility player in the industrial energy arena. It cleans and sterilizes, dries and concentrates, separates and evaporates. In cookery, it preserves flavor, texture, and retains nutrients. In chemistry, it fosters reactions by controlling process pressure and temperature. In biotechnology, it’s essential for growing production organisms. Steam ranges in purity from boiler grade for routine tasks, to culinary grade “Clean Steam” for food and dairy, and graduates up to super pure, pyrogen-free steam for biopharmaceutical use.

Magnetrol, a world-leading manufacturer of level and flow instrumentation, has assembled an excellent application summary for the use of level instrumentation in steam generation.

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YOU CAN DOWNLOAD THE APPLICATION SUMMARY FROM THIS PAGE ON THE M.S. JACOBS WEBSITE

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Blowdown Tanks in Steam Systems

Schematic for applying blowdown tank in steam system.
Image courtesy Colton Industries

Blowdown, in a steam system, serves as a means to remove condensate or reduce the accumulation of minerals and contaminants in a boiler. The temperature and pressure of the effluent precludes its discharge into most municipal sewers, requiring a means to collect the discharge and reduce its temperature prior to final disposal.

A blowdown tank is designed as a receiver which vents flash steam to atmosphere and provides for cooling of the condensate prior to final discharge. A vent connection at the top of the tank is normally routed to a safe discharge location outdoors. In some cases, a condenser may be applied to the vented steam. The condensate collects in the tank and cools as heat is radiated from the tank walls, generally steel or stainless steel. Faster cooling can be accomplished with the incorporation of a thermostatic cooling valve that mixes cold water with the condensate.

The blowdown tanks have no moving parts and few requirements for maintenance. Good practice calls for periodic inspection for wall erosion and corrosion. An inspection hatch provides access to the tank interior.

Share your steam system requirements and challenges with specialists, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

Steam System Blowdown Tanks from MSJacobs-Cali

Commercial and Industrial Process Heating Methods

Electric heating element of special design

Many industrial processes involve the use of heat as a means of increasing the energy content of a process or material. The means used for producing and delivering process heat can be grouped into four general categories.

• Steam
• Fuel
• Electric
• Hybrid

The technologies rely upon conduction, convection, or radiative heat transfer mechanisms, solely or in combination, to deliver heat to a substance. In practice, lower temperature processes tend to use conduction or convection. Operations employing very high temperature rely primarily on radiative heat transfer. Let's look at each of the four heating methods.

STEAM

Steam based heating systems introduce steam to the process either directly by injection, or indirectly through a heat transfer device. Large quantities of latent heat from steam can be transferred efficiently at a constant temperature, useful for many process heating applications. Steam based systems are predominantly for applications requiring a heat source at or below about 400°F and when low-cost fuel or byproducts for use in generating the steam are accessible. Cogeneration systems (the generation of electric power and useful waste heat in a single process) often use steam as the means to produce electric power and provide heat for additional uses. While steam serves as the medium by which heat energy is moved and delivered to a process or other usage, the actual energy source for the boiler that produces the steam can be one of several fuels, or even electricity.

FUEL

Fuel based process heating systems, through combustion of solid, liquid, or gaseous fuels, produce heat that can be transferred directly or indirectly to a process. Hot combustion gases are either placed in direct contact with the material (direct heating via convection) or routed through tubes or panels that deliver radiant heat and keep combustion gases separate from the material (indirect heating). Examples of fuel-based process heating equipment include furnaces, ovens, red heaters, kilns, melters, and high-temperature generators. The boilers producing steam that was described in the previous section are also an example of a fuel based process heating application.

ELECTRIC

Electric process heating systems also transform materials through direct and indirect means. Electric current can be applied directly to suitable materials, with the electrical resistance of the target material causing it to heat as current flows. Alternatively, high-frequency energy can be inductively coupled to some materials, resulting in indirect heating. Electric based process heating systems are used for heating, drying, curing, melting, and forming. Examples of electrically based process heating technologies include electric arc furnace technology, infrared radiation, induction heating, radio frequency drying, laser heating, and microwave processing.

HYBRID

Hybrid process heating systems utilize a combination of process heating technologies based on different energy sources or heating principles, with a design goal of optimizing energy performance and overall thermal efficiency. For example, a hybrid steam boiler may combine a fuel based boiler with an electric boiler to take advantage of access to low off-peak electricity cost. In an example of a hybrid drying system, electromagnetic energy (e.g., microwave or radio frequency) may be combined with convective hot air to accelerate drying processes; selectively targeting moisture with the penetrating electromagnetic energy can improve the speed, efficiency, and product quality as compared to a drying process based solely on convection, which can be rate limited by the thermal conductivity of the material. Optimizing the heat transfer mechanisms in hybrid systems offers a significant opportunity to reduce energy consumption, increase speed and throughput, and improve product quality.

Many heating applications, depending on scale, available energy source, and other factors may be served using one or more of the means described here. Determining the best heating method and implementation is a key element to a successful project. M.S. Jacobs and Associates specialize in electric heating applications and facets of the industrial production of steam. Share your process and project challenges with them and combine your facilities and process knowledge and experience with their product application expertise to develop effective solutions.

Improved Level Measurement Contributes to Reduced Heat Rate in Steam Production

Minimizing heat rate and emissions for steam plants

Steam production is a costly operation in any facility, but is of paramount importance in power generation plants. The bottom line of a combustion based power generation facility is sensitive to the cost of input fuel. Measures that can be taken to reduce fuel input for a unit of power output (called heat rate) can translate directly into profitability. An additional benefit of reducing heat rate is a commensurate reduction in emissions.

A major contributor to heat rate reduction is the recovery of heat from the process and transference of that heat into the boiler feedwater. A sizable feedwater preheater of the shell and tube type is used to recover the heat. Shell and tube heat exchanger efficiency can be maximized with accurate control of liquid level.

Magnetrol, globally recognized leader in level measurement technology, makes the case for using guided wave radar level measurement technology as the most advantageous means for this application. The video below describes the process and how the guided wave radar level transmitter can provide the best performance.

Magnetrol has an information kit devoted to heat rate reduction. Share your steam system and level measurement challenges with a product specialist, and ask how you can get the Heat Rate Reduction Kit. Combining your facility and process knowledge with the product application expertise of a specialist will result in effective solutions.

Float and Thermostatic Steam Traps

Float and Thermostatic Steam Trap
Courtesy Colton Industries

Steam traps are found on almost every steam system in commercial and industrial sites. The trap is a self-contained automatic valve that allows condensate to drain from a steam containing system, while retaining the steam within the system. Non-condensible gases can also be removed by a steam trap with a thermostatically controlled port.

Steam based heating relies on the delivery of the latent heat of the steam to a heat exchanger or piece of utilization equipment. Once the latent heat is delivered, condensate (basically hot water) forms. The condensate contains no latent heat and provides comparatively little value as a heat source. Utilization equipment and heat exchangers have their performance predicated upon a supply of steam, not hot water. A properly selected steam trap will remove condensate across a range of steam utilization rates, keeping the system operating at the rated capacity.

The steam trap routes the condensate out of the steam containing portion of the system, often on a return trip to the boiler. Cycling the condensate back through the system for re-boiling contributes greatly to steam system energy efficiency. Condensate removal is accomplished with a float. Non-condensible gases are vented through a thermostatically controlled port on the unit.

More details on steam traps are included below. Share your steam system challenges with a product specialist, combining your facility and process knowledge with their product application expertise to develop effective solutions.

Float and thermostatic steam traps for condensate return from MSJacobs-Cali

Building Steam System Efficiency for Profitable Returns

Improvements in steam system efficiency can yield
substantial return on investment

Steam, an energy efficient, reliable, scalable form of transferring heat, is utilized throughout commercial, industrial, and institutional settings. The ubiquitous adoption and use of this heat transfer medium has resulted in steam generation ranking as a substantial line item on any organization's financial operating report. The scale of many steam production operations can produce some sizable payback opportunities from modifications that improve efficiency or reduce maintenance requirements.

The application of modern precision measurement instrumentation is one area where comparatively modest investments in system improvement can yield ongoing returns. Magnetrol International, a globally recognized leader in the design and manufacture of flow and level instrumentation, has produced a white paper describing aspects of the steam cycle that are candidates for profitable improvement and how various measurement technologies can help garner the maximum attainable gain in efficiency.

The paper is included below, and will prove to be informative and interesting reading. More information is available on specific instrument recommendations from product application specialists. Share your steam system challenges with them and work together to find the best solutions.

Optimizing the Steam Generation Cycle and Condensate Recovery Process from MSJacobs-Cali

Positive Returns From Steam Generation and Condensate Recovery Efficiency Gain

Steam systems are excellent candidates for cost saving
through increased efficiency.

The generation of steam is a lifeblood operation to many commercial and industrial operations around the world. The large scale of its use can make steam generation one of the largest energy consumption activities for an industrial plant or commercial building. The size and complexity of steam systems, with generation, condensate handling, heat recovery, and feedwater treatment, provides a number of areas where inefficiencies can cost very substantial sums of money. Conversely, enhancing efficiency toward a maximum attainable level will yield very large savings in operating costs.

Magnetrol International, a globally recognized leader in the design and production of flow and level controls for commercial and industrial use, has produced a video summarizing the elements of the steam system that are good candidates for upgrade, as well as general direction on how to achieve increased efficiency for each. In keeping with the company's line of level and flow measurement products, the focus is on how accurate and robust instrumentation can improve overall system performance and generate a decidedly positive return on the time and funds invested.

Invest a few minutes in the video below and learn how the operating efficiency of your steam system can be elevated with an instrument upgrade. There is a white paper on the same subject available on request. You can also receive a listing of the specific Magnetrol instruments that can be applied to steam systems, with a short description of where each is applied. Reach out to a product application specialist and share your steam system challenges. Combining your system knowledge with their product application expertise will yield the best solution.