With the rise in demand for heating and temperature control in industrial processing, many facilities are looking to thermal fluid for its ability to meet the needs of process heating. While traditional boilers offer a solution familiar to most manufacturers, those same manufacturers may not be familiar with what thermal fluid systems have to offer. Why would one benefit from looking into this alternative for process heating applications? Here are the top five advantages of choosing a thermal fluid heating system.
1. Achieve High Temperature at a Low Pressure
When comparing indirect process heating mediums used for heat processing, the primary focus should be on the big three: steam, hot water/glycol and thermal fluid. While each medium and its supporting heat equipment offer advantages and disadvantages, thermal fluid heaters are the front-runner in terms of operating temperatures. Standard thermal fluid heating system designs can cover temperatures ranging from 32 to 650°F (0 up to 343°C). By comparison, a standard steam system is only capable of heating from 250 to 350°F (121 to 177°C) at 150 psig design pressure. A standard hot water/glycol system can operate between 32 and 250°F (0 and 121°C).
It also is important to note the low operating pressures that a thermal fluid system offers. The pressure primarily is determined by the rating of the circulation pump; it typically ranges between 50 and 75 psig. This pressure only fluctuates slightly with temperatures and depends on the physical properties of the specific thermal fluid chosen.
While thermal fluid heaters may be capable of operating at a constant pressure, a steam boiler cannot. The operating pressure for 350°F (177°C) steam is at 120 psig. This is substantially more than what you will ever see in a standard thermal fluid system. If higher temperatures are required with a steam boiler, it is necessary to consider high pressure steam, and the required pressure would rise exponentially.
With the rise in demand for heating and temperature control in industrial processing, many facilities are looking to thermal fluid as a heat transfer medium for its ability to meet the versatile needs of process heating.
2. Install Heating Equipment Outdoors
Because thermal fluid heaters are designed as closed-loop systems and do not require topping up with additional fluids under normal operating conditions, these systems offer flexibility as it relates to equipment installation. Thermal fluid heaters are an indirect heating source, so they can be located remotely from the point of use. This means users do not have to be concerned with having the heater on the production floor adjacent to the process. This offers advantages, particularly for locations where building space is at a premium.
When an outdoor installation is required, a thermal fluid heater provides for a simpler install outdoors than a steam or hydronic boiler would. This is largely due in part to the lack of freeze protection needed. While thermal fluid systems do not require freeze protection, it is important to select a fluid that will maintain fluid flow and proper viscosity at the low ambient temperatures in which the heater may operate.
3. Minimize Maintenance
Thermal fluid systems are simple-circuit, closed-loop systems that do not require fluid makeup. Being such a simple circuit, maintenance requirements are reduced when compared to a steam system. Though thermal fluid heaters still require similar housekeeping and combustion checks as that of a steam boiler, they do not require a daily blowdown, regular water treatment, annual pressure-vessel inspections, hand-hole gasket replacement, retubing or steam-trap maintenance. (While these are general suggestions, you should always follow your manufacturer’s suggested maintenance schedule for optimal performance.)
It is important to note the low operating pressures a thermal fluid system offers.
4. Operate Without Stationary Attendant
Rules, regulations and codes change over time, and this can affect heat processing equipment selection. Recently, boiler attendant laws are becoming an increasing occurrence and requirement in some areas. (Consult your local codes and regulations for current requirements in your state and locality.) Such laws require a stationary engineer be on-site in the boiler room while the steam boiler is operating. For many plants, this typically requires at least one specialized employee to be on-site any time the steam boilers are operating.
These requirements typically address fired-steam boilers; as a result, the option to utilize an unfired steam generator has grown in popularity. For plants currently using both steam boilers and thermal fluid heaters, this is a popular option.
5. Central Plant Heating
Oftentimes, facilities have multiple processes for their manufacturing operations. In these cases, it may be necessary for manufacturers to have a high temperature process alongside a requirement for steam injection. In a traditional install, such a manufacturer would have a thermal fluid heater alongside a steam boiler. This would allow the high temperature process to be met while also addressing the steam demand.
By utilizing heat exchangers and unfired steam generators, a plant would be able to meet any additional demands that would exceed the traditional thermal fluid heater. Such demands might include steam injection or sterilization, hot water for wash down, or any existing process user with coils designed for steam or hydronic heating. Both of these offerings typically utilize a control valve to modulate the required thermal fluid flow to the heat exchanger. Because high temperature thermal fluid is already being circulated, the steam or hot water can be provided almost instantaneously.
Thermal fluid heaters are an indirect heating source, so they can be located remotely from the point of use.
A central system offers advantages; among them, maintenance personnel need only learn the operation and controls of one heating platform. While there will be the maintenance and water treatment requirements to go with an unfired steam generator, users are able to enjoy the lower maintenance requirement of the thermal fluid heater. A central plant also provides the advantage of the potential to avoid the expense of a mandatory boiler engineer on-site.
In conclusion, while thermal fluid heaters certainly are not new to the market, their benefits often seem to be overlooked by processors. Thermal fluid heaters offer the ability to perform at high temperatures with low pressures. Additional benefits include outdoor installation, minimal maintenance, reduced need for a stationary attendant and the benefit of central plant heating.
Next time you may be thinking about updating your facility’s process heating equipment, consider a thermal fluid heater: a versatile, convenient and efficient heat source.