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Pre-Engineered Thermal Fluid Systems vs. Custom Thermal Fluid Systems – How to Decide What You Need

Pre-Engineered Thermal Fluid Systems vs. Custom Thermal Fluid Systems – How to Decide What You Need 

Depending on the needs of a particular application, either a pre-engineered thermal fluid system or a custom-engineered thermal fluid system may be ideal. In this blog post, we’ll cover the differences between these two types of systems to help you determine which is best for your application. Both feature unique benefits, which is why it’s important to understand their differences when deciding which to use for your project.

Pros and Cons to Each Heating System

When selecting a thermal fluid system is critical, it’s important to:

  • Define the application’s unique performance requirements
  • Thoroughly assess the installation requirements and any specific facility needs
  • Compare different thermal system suppliers and learn about their products and how they approach projects for their customers
  • Determine how to properly install and operate the system in your facility

    light blue circle with an icon of a lightbulb with gears inside

Keep in mind that any mistake made in these areas may negatively impact your project. Whether you fail to assess the different heater designs or don’t take the time to compare suppliers, these and other mistakes are difficult to correct once you start installing your system. Fortunately, Sigma Thermal is here to provide plenty of guidance to ensure you make the right decisions regarding your thermal fluid system. 

One key decision you’ll need to make during system selection is whether to use a pre-engineered system, a custom-engineered system, or a combination of the two. To help you make this critical decision, the following are some of the pros and cons of each type of system.

Pre-Engineered Thermal Fluid Systems

The main advantages of pre-engineered thermal fluid systems include:

  • Reduced capital cost due to standard bill of materials
  • Faster delivery times because no engineering is required
  • Fully defined dimensions, drawings, and performance prior to purchase
  • Simplified projects and reduced site or plant engineering expenses due to the lack of drawings that require review, revisions, or approval

Custom Engineered Thermal Fluid Systems 

thermal fluid system

On the other hand, custom thermal fluid systems are often a better choice for more complex installations or processes. You may want to implement one of these systems if you plan to provide guidance on or specify certain factors such as:

Process Considerations

For custom engineered thermal fluid systems, you should provide information regarding the following process considerations:

  • System flow rates
  • Fuels, including biogas, waste gas, liquid fuels, off-spec fuels, variable fuel compositions, or dirty fuels
  • Strict requirements for emissions
  • Heat transfer fluids such as silicone-based fluids, molten salt, or ultra high-temp synthetic oils

Review and Approval of Drawings

In some cases, you may want to directly influence:

  • Connection location and orientation
  • Mechanical specifics such as configuration, materials, and paint
  • Certain system components if your company has required specific instruments, valves, pumps, or other buy-out equipment.
  • Factory interconnection and skid mounting for various components, such as mounting an expansion tank, pump skid, heater, and drain tank on one skid frame
  • Custom secondary loop skids for auxiliaries such as indirect steam generators, temperature control units, control valves, and process coolers

A Hybrid Approach – Mixing and Matching Pre-Engineered and Custom Components

At Sigma Thermal, we offer a modular approach to pre-engineered thermal fluid systems, which facilitates the combination of both pre-engineered and custom-engineered systems. Using this hybrid approach, you can use pre-engineered components for areas that don’t require customization. At the same time, you can customize the specific areas over which you want more control. If, for example, you can use a pre-engineered heater and pump skid design, but you have a large system volume and need a large custom expansion and/or drain tank, you could take a hybrid approach to the system design.

Using a hybrid approach to system selection, you can save more time and cost while simplifying your systems. Additionally, you’ll be able to easily adapt systems for specific project requirements. 

Process Heating Systems from Sigma Thermal

The experienced professionals at Sigma Thermal specialize in pre-engineered and custom-engineered thermal fluid heating systems. Our equipment allows for optimal installation, operation, and fulfillment. If you require pre-engineered thermal fluid systems, we offer both our HC2 gas-fired heaters and SHOTS electric heaters. We can also work with you to design a completely custom solution if you want to specify certain components and design elements.

For additional information about our thermal fluid systems, contact us today with any questions or concerns. We can also help you find the ideal solution when you request a quote from us.

Biomass Energy Systems

With decades of global experience in the energy industry, Sigma Thermal knows how to provide robust industrial solutions designed and engineered to meet even the most demanding client specifications. Our biomass fired energy systems provide minimal emissions and finite combustion control, all while accepting a wide range of waste fuels with varying sizes, chemical compositions, and moisture content. 

Sigma Thermal’s reciprocating grate furnace allows for the efficient, complete combustion of waste materials with high ash, high moisture content and low heating value. Keep reading for more information about how these systems work as well as the different energy delivery systems that we offer.

biomass systemHow Does a Biomass System Work?

Biomass energy systems all generally consist of three components—fuel handling, ash handling, a furnace, and a control system. Biomass equipment employs these four systems to convert raw organic material into fuel in a series of steps:

  1. Fuel preparation. Before biomass equipment can effectively handle raw material, it must process and prepare the biomass used for fuel production. Solid, liquid, and gas biomass all require different processing techniques to ensure consistency and efficiency, such as drying, screening, grinding, and separating. 
  2. Fuel intake and handling. The fuel handling system includes the initial feed and an intermediate storage bin. Fuel moves from the feed to the storage bin, where specialized equipment measures it out and subsequently distributes it into the furnace and onto the reciprocating grate. 
  3. Material combustion. Biomass energy systems heat and combust the prepared materials with process heating equipment, achieving drying and gasification by creating hot gases that will move along through the next steps of the process.
  4. Gas capture. Newly created hot gases move through two chambers, the upper combustion chamber and the secondary combustion chamber, which capture and store the gases for future use. Burning biomass for energy generates carbon dioxide as a byproduct, so proper gas capture and removal is crucial to keeping carbon emissions low. 
  5. Ash handling. Lastly, the ash handling system captures the grate ash byproduct, which is dropped from ash hoppers to the ash conveyor. This conveyor is submerged underwater for improved ash management and transports the ash outside of the system where it can be collected and disposed of.

Energy Delivery Systems & Equipment for Enhanced Performance

biomass energy system

Bio energy systems provide several benefits over traditional energy generation solutions, including enhanced performance, efficiency, and more. Biomass fired energy systems are a source of renewable energy, which makes them eligible for a host of benefits like Renewables Energy Certificates (RECs) for each MWh of power created or even process heat RECs. . Not only is biomass renewable, but it also boasts carbon savings that have both environmental and financial benefits, especially in the industrial sector. 

Biomass energy delivery systems are also incredibly efficient regarding total cost and material usage.  Advanced gasification technology like the processes described above can have up to 80-90% thermal efficiency, which drastically reduces input costs and expands profit margins. Operational fuel cost savings and reduced fuel price volatility are other key benefits of biomass energy  since organic waste energy sources are much more available and abundant than nonrenewable sources of fuel. Finally, biomass fired energy is considered an efficient combined heat and power (CHP) system as it simultaneously generates both heat and electricity.

At Sigma Thermal, we offer several different types of energy delivery systems: 

  • Biomass Fired Hot Gas Generators. These systems cleanly generate hot gas for direct heating requirements.
  • Biomass Fired Thermal Fluid Heaters. Built for indirect heating, these systems use thermal oil or fluid. 
  • Biomass Fired Steam Boilers. Steam boilers generate steam directly from wood-fired furnaces. 
  • Thermal Oil to Steam Generation. These systems use a thermal oil heat exchanger to generate low-pressure steam.

Let Our Process Heating Experts Assist You

Partner with our team of industry veterans to unlock the benefits of bio energy systems. From highly engineered process heating equipment to standard packaged heaters, Sigma Thermal’s dedicated experts know how to find the perfect biomass energy systems for your individual needs. We believe that successful energy delivery systems require not only advanced industry knowledge and applied field experience but also exceptional customer service every step of the way. These three keys to success bind our team together and provide a powerful framework for consistently crafting exceptional biomass equipment and processes. 

For more information about our biomass energy systems, contact us or request a quote today. 

5 Industrial Applications for Direct Fired Heaters (API 560 & Non API)

Rendering Radiant Convective Heater

Direct fired heaters use one of three possible methods for heat transfer:

  • Radiant-convective heat
  • Radiant heat
  • Convection heat

Radiant–convective style direct fired heaters are a popular style of heater and are used more often than not. These heaters utilize a bare tube radiant zone in combination with a bare / finned convection section. The most typical configurations are vertical cylindrical, A-frame, and cabin style. Sigma Thermal offers all types of direct fired radiant–convective heater designs including API 560 compliant systems.

Convection style direct fired heaters provide the benefits of a direct-fired heater, but eliminates some of the drawbacks associated with radiant heat transfer. In specific temperature-sensitive applications, radiant heat transfer can be undesirable, as radiant heat transfer tends to be more harsh and unevenly distributed around the coil surface.  To minimize the impact effect of the radiant heat transfer to the process coil, Sigma Thermal’s convection style direct fired heaters are designed to utilize a separate combustion chamber and flue gas recirculation. With this design, the combustion chamber temperatures are reduced to 1,400°F. 

API 560 Heaters vs Non API Heaters

Convection or radiant-convective direct-fired heaters can be designed using API RP 560 guidelines and practices created for fired heaters used for general refinery service. These guidelines are established by the American Petroleum Institute (API). Typically if the application involves the direct heating of crude oil, API560/ISO 13705 standard design guidelines will apply.  For almost all other applications (i.e. regeneration gas, thermal oil heating, water, glycol, and temperature gases), more optimal designs are available that lower the capital and installed cost, footprint, fabrication, installation time, and freight cost. A practical strategy to use to obtain an API-style design, without incurring unnecessary costs for irrelevant design elements (that are not useful for some applications), is to use API 560 as a guideline with key exceptions. 

5 Applications for Direct Fired Heaters

Regeneration Gas Heating

Regeneration gas heaters remove unwanted moisture from high-temperature process streams, such as natural gas. The wet gas runs through a desiccant-style or molecular sieve bed drying system that captures moisture from the fluid stream, leaving a purer form of the gas that is ready for additional processing and storage. The regeneration gas heater then dries the desiccant so it can be reused. Regeneration gas heating systems are also common in air separation facilities, where water and carbon dioxide are removed from the surrounding air, allowing air to be cooled into a liquid.

Process Air Heating

Process air heating, in combustion turbine systems, improves combustion ability and the reliability of the  system. Process air heating also  temperature control for process air, either at specific locations or facility-wide. Common examples of this type of heater include water-glycol systems and thermal oil systems. Robust, reliable, and long-lasting, process air heating systems see frequent use for precision temperature control in commercial food processing ovens and feeding heated air into industrial process consumers.

Viscosity Reduction

Heating heavy liquids reduces their viscosity, reducing the level of power required to pump and transport them in process systems and pipelines. This process has become common to facilitate easier transportation of crude oil and its various derivatives. Overheating crude oil will damage it and reduce its quality, making precision control essential during viscosity reduction processes. 

Skid-mounted indirect heating systems are often used near oil wells in remote locations, offering precision temperature control by heating oil through a heating medium. Some operations also use direct oil heating, which can be managed properly using low watt-density electric heating elements and convection-only style direct-fired heaters.

Inline Liquid or Gas Heating

In opposition to tank heaters or full process system heaters, inline heaters provide heat for fluids at a specific point in a process, making the fluid ready for its intended purpose. By only heating the gas or liquid that’s immediately needed, users significantly reduce energy consumption and associated expenses. Inline heaters may be either direct-fired or electric, depending on their intended application.

 Thermal Oil Heating

Thermal oil heating systems provide indirect heating using thermal oil as a heat transfer medium. Thermal oil provides an ideal medium for high-temperature operation, facilitating temperatures up to 600°F with organic oils, or up to 800°F with synthetic oils. Thermal oil heating has broad applications, including reboilers, tank heating, press heating, and numerous other industrial use cases. Thermal oil heating systems work well for processes that require high-temperature operation and precision control.

Sigma Thermal Solutions

The above guide demonstrates the impressive versatility of direct fired heating systems. Whether you need to design a unit to suit one of the applications we’ve discussed here or an entirely new purpose, Sigma Thermal Solutions can produce direct fired heaters customized to your demands. Our business serves customers from an array of industries, including aerospace, agriculture, automotive manufacturing, chemical processing, food processing, gas production, mining, oil processing, power generation, paper manufacturing, wastewater processing, and more.

Our signature Sigma Thermal convection-style, API 560, and non-API radiant-convective heaters range from 1MM to 80 MM BTU per hour. To learn more about ordering direct fired heaters, contact an expert from Sigma Thermal Solutions today. 

Sigma Thermal Solutions was founded on the belief there are three keys to success: exceptional engineering knowledge, practical field experience, and honest customer service. We look forward to helping you fulfill all your company’s heating needs!

The Advantages of Using Molten Salts for Process Heating

Molten salts, also known as salt melts, comprise a variety of products that are used across many applications. Some applications that rely on molten salts include steel heat treating and annealing, high-temperature process heating, and thermal storage for solar thermal power plants. Depending on the needs of a specific application, different salts are available to use such as chlorides, bromides, fluorides, organic salts, and nitrates. Many applications use a eutectic blend of potassium nitrate and sodium nitrate.While there are several heat transfer fluid options available, molten salts are more ideal for certain applications due to the specific features unique to them.

Molten Salt

Why Molten Salts?

There are several advantages of molten salts that make them appealing for use in a wide range of applications. The molten salts that are used most frequently in heat transfer applications are nitrate salts due to their low salt melting point, thermophysical properties, low vapor pressure, high operating temperature, corrosion performance, and low toxicity.

Molten salts help increase the maximum temperature limits in which a liquid heat transfer media can be utilized. Although individual salts are usable in these applications, combining two salts together helps reduce the melting point. The reduced melting point enables lower minimum operating temperatures, which minimizes the risk of freezing. 

For example, the melting point of sodium nitrate is 584 °F or 307 °C, and the melting point of potassium nitrate is 631 °F or 333 °C. Combined, the two salts have a melting point of 431 °F or 222 °C. This melting point significantly expands the salt’s operational flexibility for use in various high-temperature applications.

If an application operates at temperatures exceeding 734 °F or 390 °C and requires a type of liquid heat transfer media, it will need to use a molten salt fluid.

Benefits for Industrial Applications?

A wide range of salt blends can help achieve specific operating temperatures required in certain applications. Compared to hydrocarbon fluids, molten salts experience minimal vapor pressure, regardless of how close operating temperatures are to their limits. As a result, high-pressure equipment and piping are almost entirely unneeded. 

Molten salts are also usable at higher temperatures compared to other fluids such as silicone fluids and synthetic oils. They also have thermal stability and good heat transfer properties. Their high efficiency makes them suitable for use as heat transfer and molten salt energy storage media, as they are eco-friendly and can reduce operating costs. 

Request Your Custom Molten Salt Systems

Depending on your application’s requirements, there are three main types of molten salt heating systems you can use. These include circulated molten salt, salt bath heaters, and direct heating for applications such as metal assembly heat treating. 

At Sigma Thermal, we can provide:

  • Circulated molten salt systems that distribute hot liquid salt as a type of heat medium to process heat consumers such as heat exchangers.
  • Salt bath heater systems that use natural convection processes and eliminate the need for circulation pumps. This equipment is designed to operate at high temperatures to supply molten salt energy.

Sigma Thermal’s experts design and manufacture a variety of systems that use molten salt energy, including hot salt tanks, circulated molten salt systems, electric heaters, and salt bath heaters. We have the resources and experience needed to design fully automated custom systems. We can help you meet all of your process needs with our innovative solutions.

To learn more about our molten salt systems and get started on a custom solution for your specific application, request a quote today.

Glycol Heaters

Certain types of heating systems, such as closed-looped thermal fluid heating systems, can use glycol to maintain heat transfer fluid to the desired temperature. While water is an ideal heat transfer medium for a certain range of temperatures, pure water has drawbacks. It can freeze below 32° F and it can corrode the internals of a heating system. Also referred to as antifreeze, glycol lowers the freezing temperature of the mixtures it is added to and it ensures that harsh weather conditions do not cause heating systems to freeze. In addition, glycol raises the boiling point of water to some degree, allowing for higher operating temperatures with less operating pressure than pure water. Glycol is also frequently purchased with corrosion inhibitors that reduce corrosion inside of the system over time. 

Why Are Glycol Heaters Important?

Without adding glycol to a heating system, expensive and potentially dangerous damage to process equipment can occur. If the heating system is shut off for some time during the winter, the system and its pipes can freeze and burst, causing water damage. In addition to preventing system freezing, glycol mixtures are also a very efficient heat transfer medium compared to oils or water alone. Water and glycol mixtures have a better heat capacity than oils and perform well in many types of heaters. There are temperature limitations relative to thermal oils, but within the right range, a water-glycol solution is an excellent choice.

Additionally, glycol heaters are valuable due to the safe heat transfer that they provide. For example, it can be dangerous to have heating elements near the process or materials, but using a glycol heating system keeps the heat source safely away from the process. Thermal oils are also a fire hazard if there is a system leak, while glycol solutions are not flammable. 

Using Glycol in Industrial Heating System Applications

Ethylene and propylene glycol are commonly used in industrial facilities for process cooling. However, they are also used in process heating systems. They are very effective in heating applications due to several properties, such as:

  • High specific heat capacity
  • High thermal conductivity
  • Low viscosity
  • Water miscibility

Water and glycol solutions present many benefits for industrial processes, on the other hand, these are not the only heat transfer mediums available. Synthetic and organic thermal oils are also sometimes selected as they work well in temperatures up to 750° F and produce very little vapor pressure. Water without additives can also be used, although within more limited conditions due to its low-temperature intolerance and boiling point. It is also possible for water to produce a dangerous amount of vapor pressure at certain temperatures. 

A water and glycol mixture can be a preferable choice in many applications since it has a higher boiling point than water alone, which can be increased further by including a higher concentration of glycol. Different types of glycol can be used for varying operating temperatures. For example, while ethylene and propylene glycol are suitable for systems with temperatures between 250–300° F, Tri-ethylene glycol works effectively up to 350° F.

Glycol Heaters from Sigma Thermal

Sigma Thermal’s glycol heaters, such as HC-2 heaters, are designed to meet all area classifications and can perform optimally in even the harshest of environments, including deserts, arctic, and offshore regions. The HC-2 thermal fluid heater is available in capacities from 1 to 100MM Btu/hr, with custom sizes also available. The heater shell is externally insulated using mineral wool insulation which is covered in aluminum cladding. 

Some other design features of glycol heaters from Sigma Thermal include advanced control system options and a double-helical coil design, which offers three passes of flue gas along a conservatively designed coil surface area. Depending on process inlet temperatures, base efficiencies can exceed 88%, and by including an optional economizer, can exceed 93% (LHV basis).

These systems allow flue gases to be cooled significantly, which eliminates the need for most internal shell insulation. Sigma Thermal carries low emissions burners that meet all emissions requirements in standard or engineered burner configurations that can be used with either traditional or alternative fuel sources. 

Sigma Thermal offers customizable glycol heaters that lower fuel and operation costs while improving efficiency. To learn more about our products, please contact us or request a quote to get started.

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