Thermal fluid systems are heating systems in which the thermal fluid, such as glycol or thermal oil, is heated and then recirculated supplying indirect heat to process equipment, materials, and systems. Because they supply indirect heat, thermal fluid systems minimize the risk of burns or heat damage to equipment. This process is also controllable, allowing for accurate temperature moderation.
Low pressure: These systems can produce high levels of heat while remaining at low pressures, unlike steam-based boiler systems.
Variability: Thermal fluid systems can be either vapor phase or liquid phase. Facilities also can choose between waste fuel-fired, oil, or gas thermal fluid systems.
Major Components of Thermal Fluid Heating Systems
While every thermal fluid system can be customized to meet the needs of its facility, they all share the same core components and processes. Four major components in them are:
The pumps control how the fluid moves throughout the thermal fluid heating system. This includes the velocity, the way in which it moves away from the burners, and the overall pressure of the system. While thermal fluid systems are generally low-pressure, a large system can introduce marginal levels of increased pumping pressure.
When you’re considering which pump to use in your next thermal fluid heating system, keep these considerations in mind:
Thermal fluid system pumps need to be built for this specific application. They can’t be substituted with boiler feed pumps or standard hot water pumps.
Your builder or service provider should choose the correct pump size based on the gravity of the thermal fluid at operational temperatures and the system’s potential pressure loss.
Different applications require different pumps. However, the top choices are generally API pumps, air-cooled mechanical seal pumps, water-cooled pumps, or magnetically coupled pumps.
Different pumps should also be constructed from different materials. For example, centrifugal pumps should be made with cast iron or ductile iron wetted parts. Positive displacement pumps should instead be made from alloy steel. However, all pumps should have mechanical seals.
Valves need to be sturdy and leak-resistant so they can control the flow of thermal fluid. Just like with pumps, valves work best when they have a bellow-type seal so they can fully close against a variety of surface textures and withstand minor wear over time.
It’s also best for isolation valves to be either globe valves or valves with ball-type controls. All valves should be cast or forged carbon steel; they can perform well with either a socket or a butt weld design.
Burners heat up thermal fluid before it is pumped through the system. Different fluids and system sizes demand different heat loads and combustion chamber sizes. That, in turn, requires a burner to keep up with size and power demands. Your thermal fluid system builder can determine the right burner based on the application, size, and other factors.
4. Control Panels
Programmable Logic Controller (PLC) packages, which we offer at Thermal Fluid Systems, provide better control over the system. They can be integrated with your facility’s existing Distributed Control System (DCS) for easier monitoring and a higher degree of safety. When integrated with the heaters, the control panels offer continuous flow monitoring through an orifice plate and differential pressure switches. Operators also can monitor the burner with the included UV scanner and monitor for pressure overages with pressure alarms, block and integrated alerts. The control panels also can include:
Redundant fluid outlet temperature alarms
High stack temperature alarms
High expansion tank level alarms
Thermal Fluid Systems Design
Thermal Fluid Systems Design specializes in creating high-quality, responsive thermal fluid heating systems, be it gas, oil, or waste fuel-fired. We also offer electrical systems. Our fuel-based systems can use the following fuel types:
Fuel oils 2, 4, or 6
Waste gas product
Each system outputs 0.5 to 50,000,000+ BTUs per hour and operates at an efficiency of up to 90%+ (LVH).
Customers can choose between horizontal and vertical configurations, as well as many options such as drain tank and secondary heating controls. Each of our thermal fluid systems can handle indoor or outdoor applications and have specially designed pumps, valves, burners, and control panels based on the intended application.
At Thermal Fluid Systems, we also offer services to help keep your new installation running smoothly. These include operator training, inspections, replacement parts, and maintenance. Our units and parts meet the following standards: ASME, API, USCG, ABS, and NEMA 1, 3R, 4, 4X, 7, and 12, NFPA, CSA.
Learn More About Thermal Fluid Systems
At Thermal Fluid Systems, we create high-quality thermal fluid heating systems built to fulfill each customer’s needs. If you need a custom-designed thermal fluid system, we’re here to help. Contact us today to learn more about our capabilities or request a quote to get started.
Pumps facilitate the movement of liquids by forming a low-pressure area at the pump inlet, which enables fluids to be forced inside by atmospheric or head pressure. In terms of pump performance, it is important to consider the physical limit that external pressure places on how high fluids can be lifted by the pump. This limitation is taken into consideration by Net Positive Suction Head (NPSH), a term that describes the difference between pump suction pressure and vapor pressure. The NPSH is the most important element to consider in a pumping system.
NPSH involves two parts: net positive suction head available (NPSHa) and net positive suction head required (NPSHr).
NPSHa refers to the NPSH available at the inlet of the pump and is calculated based on several variables related to the specific system.
NPSHr, which is supplied by the pump manufacturer, is the NPSH necessary for the pump to operate without experiencing cavitation. Cavitation occurs when bubbles rapidly form at the pump’s inlet, then abruptly collapse to create a shockwave. It is crucial to avoid cavitation as it can cause permanent damage to the pump.
Calculating Net Positive Suction Head
Calculating NPSH is essential in order to prevent cavitation, improve efficiency, and ensure optimal pump performance. When selecting the most suitable pump for a particular application, it is important to make sure that the NPSHa is greater than the NPSHr to avoid cavitation. In other words, the system must have a greater amount of suction-side pressure available than the amount required by the pump.
NPSHa is calculated using this formula:
NPSHa = Ha ± Hz – Hf + Hv – Hvp
Ha: Absolute pressure, typically atmospheric pressure, being exerted on the liquid’s surface
Hz: Distance between the liquid surface within the tank and the pump centerline
Hf: Losses due to friction in the suction piping
Hv: Velocity head at the pump suction port
Hvp: Absolute vapor pressure of the liquid at pumping temperature
Using Net Positive Suction Head to Select a Pump
As mentioned, the most important factor to consider when selecting a pump is the NPSH. The margin of error between your calculated NPSHa and the manufacturer-provided NPSHr should be 10% or greater to ensure that cavitation is avoided. Other factors to consider when selecting a pump include:
Temperature. The higher the liquid temperature, the greater its vapor pressure. This has a significant effect on the NPSH equation, causing the NPSHa to decrease. It is important to consider this, especially if the pump is being used in high-temperature applications.
Suction-specific speed (Nss). This single value is calculated from three factors: the amount of head generated by a pump, the pump operation speed, and the amount of NPSH necessary for pump operation. High Nss values could indicate that a pump is prone to cavitation.
Distance between pump and suction source. Due to its effect on the NPSHa, the distance between the pump and the suction source should be considered.
Pump design. Pump design, age, and the rotational speed of its impellers will all influence the NPSH required for the pump to operate properly.
Net Positive Suction Head Solutions by Thermal Fluid Systems, Inc.
Thermal Fluid Systems, Inc. is a thermal fluid heater and hot oil system supplier with 40 years of experience in the field. Our extensive experience allows us to be involved in every step of our customer’s projects, from design and engineering to fabrication and after-sales support. By closely communicating with each customer to understand their specific project challenges and requirements, we can recommend and install the pump that is best suited for a particular application. Our goal is to save our customers from the stress of having to worry about the expensive repairs or unexpected downtime that can come with selecting the wrong pump for a system.
Additionally, we also perform system and control upgrades, provide onsite-technical support, and offer an extensive inventory of replacement parts. To learn more about our many services and capabilities, please contact us today or fill out a request for a quote.
Thermal Fluid Systems, Inc. specializes in the design, supply, and servicing of hot oil systems, also referred to as thermal fluid heating systems for the process industries. Our services include complete system design and supply, as well as parts supply and maintenance throughout the life span of the system. The systems we offer are expertly designed and serviced to produce consistent and high-temperature heating at low pressures
We offer a wide range of replacement parts— including pumps, valves, burners, control panels—not only for our own thermal fluid systems but for other manufacturers’ systems including Geka, GTS, Konus, Eclipse and Fulton among others.
The types of high temperature hot oil pumps we supply include:
Canned motor pumps
Mechanical seal type pumps
And we carry top brands including KSB, Sihi, Allweiler, Dean, Kontro, Dickow and more.
What Types of High Temperature Pumps Are Available for Hot Oil Systems?
Selecting high-quality pumps and replacement parts from a reliable manufacturer helps keep hot oil systems working properly and smoothly
At Thermal Fluid Systems, we can source pumps and parts from major manufacturers and customize your systems to use one type of pump throughout the facility. Available for fast delivery and installation, our inventory includes the following pumps:
Magnetic drive pumps—also commonly referred to as mag-drive pumps—use magnets to rotate the internal impellers that push fluid through the hot oil system. The use of magnets removes the need for external shafts and their accompanying seals, which eliminates the risk of leakage. This characteristic makes this type of pump ideal for systems that have expensive, corrosive, or toxic fluids that must be prevented from leaking out of the system as either a liquid or gas.
Mag-drive pumps have several advantages, including:
Low risk of leaks: These pumps don’t have external shaft components, which eliminates many of the potential leak vulnerabilities possessed by other types of pumps. These pumps are also tested to reduce the risk of fluid (either gas or liquid) leaks.
Low cost of maintenance: Mag-drive pumps require very little maintenance throughout the life span of the system. While the power requirements may cost more than comparable pump systems, that expense is largely negated by the lack of maintenance and repair costs.
CANNED MOTOR PUMPS
Canned motor pumps serve as an alternative to magnetic drive pumps. These pumps similarly do not rely on mechanical seals and offer a low risk of leakage when employed, as the moving pump parts are contained within a hermetically sealed chamber. Typical applications include use in systems that need to guarantee zero leakage, such as systems with expensive fluids, systems with radioactive or toxic coolants, and any system with corrosive fluids.
Some of the other advantages of using canned motor pumps include:
Reduced noise: These pumps operate more quietly than other hot oil system pumps.
Explosion-proof and airtight parts: Designed to handle pressures that are greater than is attainable by most systems, the seals on canned motor pumps are airtight. These qualities also contribute to the leak proof guarantee.
Space efficiency: These pumps are available in a compact design. Because the motor and pump components are contained within a joint unit, canned pumps require half the space or less of comparable sealed pumps
API pumps are designed to meet the American Petroleum Institute (API) standards for hydrocarbon pumps. Specifically, API pumps meet the API 610 standards for centrifugal pumps that are rated for high-pressure conditions, such as are found in the petroleum, petrochemical, and natural gas processing industries. These pumps are built with durable pump casings that are designed to withstand high pressures and temperatures; Qualities which help to prevent explosions and reduce the need for frequent servicing or maintenance of the pump.
ANSI pumps are another type of process pump which is designed to meet the ANSI, or American National Standards Institute, standards. However, these pumps are built for systems that handle thin liquids such as water and alcohols. API pumps, on the other hand, are built to handle viscous hydrocarbons without cracking under the increased pressure. Common applications for API pumps include oil refineries and other processing plants along oil supply chains.
MECHANICAL SEAL TYPE PUMPS
As suggested by the name, mechanical seal type pumps utilize a mechanical seal that acts as a check valve and slider bearing for the pump. This component prevents fluids from leaking out of, and air from leaking into, the pump during operation. However, through regular use, it experiences wear, and eventually fatigue, necessitating replacement of the seal component.
TFS, Inc. also offers mechanical seal pumps that are available as air- or water-cooled.
CONTACT THERMAL FLUID SYSTEMS TODAY
Using the right pump for your facility’s thermal fluid heating system can make it safer, more efficient, and more profitable. To find out how Thermal Fluid Systems, Inc. can help save you time and money, contact us, or request a quote today with the details of your system design or part replacement needs
Resistance temperature devices (RTDs) provide accurate process temperature readings within thermal fluid systems. Typically made from platinum, RTDs use known mathematical relationships between resistance and temperature to measure a fluid’s heat.
RTDs go by a variety of names, including resistance temperature detector, pt-100, platinum resistance temperature detector, and resistance thermometer. Regardless of what they’re called, these devices generate accurate, repeatable readings at temperatures up to 900° F, making them ideal tools for monitoring temperatures within fluid systems.
HOW DOES AN RTD SENSOR WORK?
As the temperature increases in a metal, resistance also increases. RTDs use this relationship to measure the heat of a process fluid.
For some metals such as platinum, this relationship is nearly linear and remains stable across a wide temperature range. As a result, the resistance measured in a platinum element corresponds closely to its temperature-and therefore the temperature of the surrounding fluid, when installed in a thermal fluid system. Copper wires transmit the actual RTD element’s resistance to a measuring instrument, which computes the associated temperature.
HOW MANY WIRES SHOULD BE USED IN AN RTD?
The number of wires is an important consideration in RTD design. With a theoretical ideal wire, the resistance registered by the measuring instrument would equal the resistance of the platinum element. In reality, the wires themselves have their own levels of resistance which must be compensated for to ensure accurate readings.
For example, a two-wire system does nothing to account for the resistance of the wires, leading to a less accurate temperature reading. Three- and four-wire RTDs, on the other hand, are carefully designed to cancel out the resistance of the wires, drastically increasing accuracy. As a basic rule of thumb: the more wires, the more accurate the reading. However, three-wire systems are sufficient for most common industrial applications.
WHAT ARE THE COMPONENTS OF AN RTD?
The two critical elements of an RTD are the platinum resistance element, which functions as the sensor, and the wire configuration, which communicates that sensor’s reading. Other important elements include:
Outside diameter (OD). The OD measures the wire and its surrounding insulation-typically no thicker than 0.5″.
Tubing material. The tube housing is often made of stainless steel, although more temperature-resistant metals might be chosen depending on the application.
Process connection. Various types of pressure fittings can be used as the process connection with many of the options resembling those used in thermocouples.
Cold end termination. At the cold end of the wire, an RTD can terminate into a plug, wire, or terminal head, among other options, depending on the measuring instrument.
RTDs offer many benefits when used in thermal fluid systems:
Highly accurate measurements
Stable metal construction
Functional in high temperature ranges
RTD VS. THERMOCOUPLE
RTDs are often confused with thermocouples, and while similar, thermocouples derive temperature measurements from the voltage change across two metals rather than the resistance of one.
Since their functionalities are so similar, it can be difficult to choose between a thermocouple and an RTD. As a general rule, RTDs yield more accurate and repeatable measurements thanks to their use of a highly stable metal sensor. They can also be easier to calibrate for the same reason.
Thermocouples, by comparison, are more complicated to configure and still generate less accurate results. However, there are a couple of reasons to choose a thermocouple over an RTD in certain applications. Thermocouples function at higher temperatures than RTDs and they can also be substantially cheaper, making them an excellent option where pinpoint accuracy isn’t necessary.
Thermal Fluid Systems carries and uses both types of sensors, and our expert staff can help you determine which is best for your application.
THERMAL FLUID SYSTEMS AND HIGH-PERFORMANCE RTDS
At Thermal Fluid Systems, we are experts in the design and construction of thermal fluid systems. One of our core considerations for every project is effective regulation, and RTDs present a means to accurately assess system metrics.
For specific questions about RTDs or general inquiries about our systems, contact our team for advice. If you’re ready to invest in an industry-leading thermal fluid system, request your quote today.
Heating systems may typically be categorized as indirect or direct. Indirect heating systems allow for more fine-tuned temperature control. There are many ways to indirectly heat substances, and one of the foremost is through the use of a thermal fluid system—also known as a thermal oil heater.
Many industrial companies have turned to thermal fluid heating or hot oil heating because of the various advantages it offers over other heating systems. A thermal fluid system is a closed looped system in which a fluid—most commonly oil—is used to heat the desired substance indirectly.
The fluid within the system can be heated in several ways, most commonly through electrical power, coalwood, natural gas or oil. Once the fluid within the thermal system has reached a specified temperature, the heat will be transferred to the end user target.
This page will provide you with all of the information you need to determine if thermal fluid heating is right for you.
Major Components of Thermal Fluid Heating Systems
As with all heat-generating systems, it’s important to know the major components of the system. Thermal fluid heating systems include these essential parts:
Burners are application-specific. System designers choose burners based on the heater’s combustion chamber size. The burners will be selected based on their capability to supply handle the heat load to the chamber.
Automated systems are safer and easier to regulate, which is why many existing thermal fluid heating systems include—or have been retrofitted to include—programmable logic controller (PLC) control packages. These systems offer smarter control of the heating system without direct interference from operators. They also allow operators to maintain safe distance from heated parts to reduce any risk of injury or accidents.
PLC control packages can integrate with a plant’s distributed control system (DCS) for quick and straightforward adoption. Some elements of these control panels include:
Continuous flow monitoring. PLC control packages include differential pressure switches and orifice plates in every heater coil to monitor continuous heat cycles.
Alarms. High stack temperature alarms and redundant fluid outlet temperature alarms monitor for temperature surges. Systems can also include tank level alarms and high or low fuel pressure alarms.
Automatic interlock. The system prevents surges in firing during startup to prevent damage to the heating system.
Burner supervision. UV flame scanners and electronic flame programmers monitor the performance of burners.
Hot water and boiler feed pumps aren’t appropriate for thermal fluid systems. They require specially designed high-temperature pumps that can handle the fluid’s pressure drops and fluid gravity. In well-designed systems, every pump is specifically made to match the expected function and heated fluid.
Common types of pumps in thermal fluid heating systems include:
Centrifugal pumps, which require ductile or cast iron wetted material.
Positive-displacement pumps, which work best when they’re made from alloy steel.
Air-cooled mechanical seal pumps, which depend on the system and usage.
Some alternatives to air-cooled mechanical seal pumps include water-cooled, magnetically coupled, or API pumps. Pumps should also have bellows-type seals.
Thermal Oil Boiler vs. Steam Boiler
Thermal fluid systems and steam boilers are two of the most common industrial heating systems. Thermal fluid heating systems offer the following advantages over steam boilers:
Better temperature control
Greater temperature range (because oils have higher boiling points than water)
Steam boilers pose a corrosion risk without proper monitoring, and they provide a lower range of temperatures for heating applications. Installing a thermal oil heating system to replace an older steam boiler can drive significant efficiencies for industrial facilities.
This can also greatly reduce maintenance demands because newer automated thermal fluid systems self-monitor their own condition and warn operators of any problems. Thermal fluid systems that use oil are also continuously lubricated by heating fluid itself, which keeps the system in better condition throughout its lifespan.
Design of Thermal Fluid Systems
Thermal Fluid Systems, Inc. specializes in designing thermal fluid heating systems tailored to specific applications and facilities.
Our full system configuration services include:
Designs for exterior or interior applications
Electrical heating system options
Optional drain tanks and secondary heating controls for varying applications
Physical unit options, such as horizontal or vertical configurations and stand-alone or skid-mounted heating units
Thermal fluid systems that can use gas, oil, or waste fuel by design—fluid options include biodiesel; bunker C; fuel oils #2, #4, or #6; natural gas; propane; or waste gas product
Three-pass, high-efficiency heater designs that evenly distribute heat throughout the system
We also provide all system components, such as:
Thermal Fluid Systems, Inc. offers a wide selection of individual components for repairs, maintenance, and retrofitting. We also provide additional services such as inspections, maintenance plans, operator training, and complete turnkey installation.
Each of our systems provides a high degree of energy output and energy efficiency. Energy output ranges from 0.5 BTU to over 50,000,000 BTU per hour. The units also have up to 90% LHV efficiency. Our systems can be designed to meet the following industry standards:
NEMA ratings: 1, 3R, 4, 4X, 7, 12
Advantages of Thermal Fluid Systems
There are numerous advantages to using hot oil heating systems, the foremost of which is their ability to control the temperatures of other fluids used in processing indirectly. This power to change certain temperature aspects is especially important in systems requiring finely tuned temperature control. The fact that the thermal system operates by heating fluids also gives it the capability to precisely time heating for the end user target.
Also, thermal systems can maintain high temperatures for extended durations, while at the same time operating at low pressures. This low-pressure operation significantly increases the level of safety for those working near the unit.
Furthermore, these systems are known for being very reliable due to their simplistic, rugged design. The longevity of the system can help industrial companies save a lot of money because they won’t have to replace the unit after a few years, as is the case with other similar competitive systems.
Thermal Fluid Applications
The applications in which a thermal fluid heater can be used are nearly endless. Some of the most widely used applications including heating of fryers, process reboilers, and convection ovens.
Often an electric heating system is preferred because it does not have any harmful emissions—such as carbon dioxide or nitrous oxide—which are common byproducts when using coal-generated heat. Therefore, they are much safer and very efficient as well.
Here for All Your Thermal Liquid and Hot Oil System Needs
When it comes to heating process fluids, few methods offer the advantages of thermal fluid systems. By implementing this type of a system, the temperature of the end product can be finely tuned, and the heat can be applied at a precise moment, allowing for extreme control. The low operating pressures of a thermal system mean that employees will be much safer when working in the vicinity of the unit.
There are dozens of uses for this type of fluid heating system, and some of the most popular include industrial convection ovens and liquid tank heating. Thermal Fluid Systems, Inc. is here to help you find the ideal solution that will improve your production and help business run efficiently.
Maximum allowable working pressure (MAWP) is an American Society of Mechanical Engineers (ASME) designation that establishes the rating for pressure-relief components on vessels. It measures the greatest amount of pressure that the weakest part of the vessel can handle at specific operating temperatures. Industrial facilities use a vessel’s MAWP to establish safety protocols and prevent explosions by ensuring the system never exceeds safe operating pressures.
At Thermal Fluid Systems, we supply complete thermal fluid and hot oil heater systems. All of our thermal fluid heaters are designed to handle a MAWP of 150 psi by default, but other MAWPs are available upon request. Additionally, every system also complies with all ASME safety standards.
MAWP vs. Design Pressure
Whereas a vessel’s MAWP is the highest level of pressure it could be exposed to, the design pressure is the highest level of pressure it should be exposed to in normal operating conditions. The design pressure establishes the highest acceptable pressure of a pressurized system, and it is generally lower than or equal to the MAWP of the system’s vessel. While the MAWP is calculated based on the physical limitations of the vessel’s weakest part, a system’s design pressure is based on the type of pressure system employed.
The vessel’s or system’s relief valve is set to the design pressure to minimize the risk of damage or explosions. Generally, the design pressure incorporates a margin of 10-25% above general operational pressures to allow for unexpected surges. This additional buffer further reduces the risk of explosions failure.
MAWPs also differ from design pressure as the former characteristic changes throughout the vessel’s lifetime. Wear, use, and corrosion of carbon steel elements gradually weaken a vessel, lowering the vessel’s MAWP. While MAWPs are printed on their vessels so facility managers can match the parts to the right system, it’s important to take the vessel’s age and wear into consideration.
What Are the Keys To Calculating MAWP?
The American Society for Mechanical Engineers establishes the standards for the design and construction of pressure-rated vessels, including acceptable MAWPs. Their established formula for calculating a vessel’s MAWP is as follows:
P = (TS x t x E)/(R x SF)
P = Maximum allowable working pressure
TS = tensile strength of the material in the weakest part of the vessel (in psi)
t = the vessel’s wall thickness (in inches)
E = the longitudinal seam efficiency, or efficiency of the weld based on a set rating (no unit)
R = the interior radius of the vessel (in inches)
SF = the safety factor (no unit)
Before calculating for MAWP, process engineers need to determine the size, shape, and required psi of a vessel, as well as the physical properties of the desired metal alloy. By doing so, the vessel can be constructed with the right structural materials and thickness to meet the calculated MAWP. Alternatively, the MAWP can be calculated for a variety of standard pressure vessels so the right vessel can be selected and added to an industrial facility system.
Once MAWP is determined, the vessel is hydrotested—i.e., filled with pressurized water at the established MAWP—to verify that the vessel can handle the pressure.
Contact Thermal Fluid Systems to Receive a Quote
MAWP is the maximum pressure a vessel can handle without risking equipment or system failure determined by the individual vessel’s physical structure and condition. This property differs from the vessel’s design pressure, which is the maximum operating pressure a system should reach, and this pressure is always equal to or lesser than the MAWP.
Thermal Fluid Systems, Inc. is a supplier and turnkey installation service provider of thermal fluid heaters and hot oil systems with standard MAWP ratings of 150 psi and custom MAWPs available upon request. To learn more about our thermal fluid heaters and hot oil systems, contact us or request a quote today.