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CESCO is proud to be an authorized representative of Heatec, an industry leader in fired thermal fluid heaters and process heaters in outputs from 0.5 to 125 million Btu/hour.
Heatec Industrial Products Web Site
We offer two-pass helical coil heaters from 0.5 to 60 million Btu/hour, all-convection heaters up to 125 million Btu/hour, three-pass helical coil heaters up to 60 million Btu/hour, vertical serpentine heaters/vaporizers, mixing tanks, bath heaters, waste heat recovery systems, code expansion tanks and piping, pump skids, and more.
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Thermal Fluid & Process Heating System |
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The thermal fluid heater is an industrial heater commonly used in closed-loop thermal fluid heat transfer systems. The heater is designed around a helical coil. Thermal fluid flows through the helical coil, gaining radiant and convective heat from hot burner gases. The heated thermal fluid then transfers heat to end users such as tanks, presses, dryers, reactors, chillers, extruders, steam generators, or other equipment. The heater's two-pass design provides high efficiency, simplicity and low maintenance. Heating coils meet ASME code.
These systems can also be designed as process heaters. In a process heating application, the heaters heat liquid or gas products as they flow through the heating coils of the heater. Process heating applications include heating vegetable oil for cooking, heating natural gas for gas regeneration, heating fuel gas or inlet air for power generation, and many others.
The thermal fluid heaters and process heaters are available in both horizontal and vertical configurations. Several models are available in each configuration. Rated thermal outputs range fro 0.5 to 60 million Btu/hour. All can be customized to meet your specific needs.
One feature of the helical coil heaters that CESCO offers is very high efficiency. This conserves fuel, greatly reducing operating costs. Thermal efficiencies of our heaters range up to 91.5 percent LHV, depending upon fluid outlet temperature, fuel, and options.
CESCO can offer a turn-key supply, including system design for your specific needs, fabrication and pre-testing, installation, tuning and calibration, and parts and service.
Major System Components:
1. Electrical power panel (optional). Houses motor starter and disconnect switch. Meets NEC and UL.
2. Combustion air motor and blower.
3. Burner with optional low NOx feature. 4. Inlet connection for thermal fluid.
5. Burner end plate. Insulated with 6-inch ceramic fiber blanket.
6. Duct (used only with optional flue gas recirculation).
7. Exhaust stack with rain cap and protection screen.
8. Helical coil. Built to ASME code.
9. Ceramic fiber blanket insulation. Three-inches thick. Additional thickness is optional. |
10. Heater shell. All-welded construction of 1/4 to 3/8-inch thick A-36 steel plate, depending on size of heater.
11. Heater shell end plate. Bolted to heater shell and insulated with 5-inch ceramic fiber blanket. Easily removed for access to heater coil. Has peep sight for inspection of heater coil and flame pattern. Larger heaters also include a manway.
12. One of four lifting eyes. Integral with shell support saddles.
13. Fabricated steel saddle. Two or more are used to support the heater, depending on its size.
14. Rigid skid fabricated from structural steel channels (or I-beams).
15. Electrical panel. Meets NEC and UL. Houses switches, controllers and status lights. All wiring is run in raceways. Wiring and terminals are numbered. All controls are pre-wired.
16. Fuel train inlet. Components of fuel train are easily accessible for service.
17. Skid extension for added support of fuel train and burner controls.
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Controls
The thermal fluid and process heaters automatically maintain the operating temperature set by the operator. Accuracy is within a half percent of the set temperature. They maintain thermal fluid temperature at the heater's outlet up to 750 degrees F (depending on variables). The systems have numerous safety features to ensure they always operate within prescribed limits. They will shut down automatically if an abnormal operating condition develops. Limit switches and sensors ensure proper operation. They monitor the burner flame, thermal fluid temperature, exhaust gas temperature, flow of thermal fluid, fuel, and combustion air pressures.
The heart of the heater control system is a flame monitor with an ultraviolet scanner. It employs solid-state electronics for reliability and long life. The flame monitor senses the burner main flame and pilot. It purges the firing chamber before firing. It turns on the pilot for a pre-programmed period and allows the main fuel valve to open only when safe. It shuts off fuel if a flame is not present.
Modulating burner controls provide suitable turndown ratios. Full modulation allows the firing rate to closely match the heat demand. This conserves fuel, reduces temperature overshooting, and eliminates constant on-off recycling.
Fuels
The heaters operate on natural gas, LPG, or commercial grade fuel oils, depending on the burner used. An optional combination burner allows switching between two different fuels.
Things that enhance value:
1. No blending of fluid from separate coils to achieve set temperatures.
2. Pipe connection is provided for hookup of inert gas to snuff burner flame.
3. Bolt-on nozzle covers permit replacement of helical coil without flame-cutting.
4. Plated bolts and assembly hardware to resist rust and corrosion.
5. Documentation furnished includes heater general arrangement, control wiring, piping and instrumentation, expansion tank arrangement, pump package arrangement, and component list.
6. Electrical and electromechanical checkout before shipment.
Options
The most popular options for thermal fluid heaters are expansion tanks, pump packages, economizers and combustion air preheaters. The expansion tank is usually mounted as a separate unit and sometimes includes the circulating pump package. The package may include strainers, valves, gauges and other items as may be needed. The economizer recovers heat from the exhaust stack and transfers it to the thermal fluid for increased efficiency. The combustion air preheater recovers heat from the exhaust stack and preheats burner inlet air for increased heater efficiency. The thermal fluid heater shown below has many options that increase performance, increase useful system life, and reduce maintenance. A convection section with finned tubing typically increases thermal efficiency 3%, and it can be designed to increase thermal efficiency up to 8%, depending mainly on operating temperatures.
1. Bolt-on front-rear heads for easy access to heating coil.
2. Bellows seal valves to restrain leaking at valve stems.
3. Minimum flow bypass valve to maintain constant oil flow.
4. Heated-insulated panel with window kit for cold weather.
5. Digital gas flow indicator for monitoring fuel supply.
6. Low media flow controller to prevent overheating coil.
7. Slip stream filter with pressure differential gauge.
8. Valves at pump inlets and outlets to isolate the pump.
9. Compound vacuum-pressure gauges to monitor inlets. |
10. Flex hoses to prevent pipe stress at pumps.
11. 300-lb flanged pipe connections to prevent leakage.
12. Pressure gauges for monitoring pump outlets.
13. Duplex pumps to provide 100% standby readiness.
14. Combustion air filter-silencer to reduce noise 86 dBa.
15. Burner with turndown ratio of 10:1 to optimize operation.
16. Flame scanner that does constant self-checking.
17. Gas flow meter to facilitate checking efficiency.
18. Convection section with finned tubes to boost efficiency. |
Thermal Efficiency
Aside from safety and reliability, thermal efficiency is probably the most important aspect of any heater. The helical coil heaters that CESCO offers, approach the theoretical limits of thermal efficiency possible in fired 2-pass heaters. The heaters can obtain thermal efficiencies up to 91.5 percent LHV. The importance of thermal efficiency is readily appreciated by comparing how much fuel they use. The chart below shows a comparison of fuel usage for heaters of various efficiencies.
| THERMAL EFFICIENCY |
| Efficiency |
Therms/Hour |
Therms/Month |
Therms/20 Yrs |
| 50% |
22.1 |
15,944 |
3,826,560 |
| 60% |
18.3 |
13,168 |
3,160,320 |
| 70% |
15.8 |
11,364 |
2,727,360 |
| 80% |
13.8 |
9,963 |
2,391,120 |
| 85% |
13.0 |
9,365 |
2,247,600 |
| 88% |
12.6 |
9,061 |
2,174,640 |
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| These usages are based on a 1-million Btu per hour heat load, operating 24 hours a day, 7 days a week, 52 weeks a year, and natural gas with a heating value of 100,000 Btu per therm. |
Efficiency is a measure of a heater's input vs. its output. The more of the input that ends up in the output, the higher the efficiency. It is theoretically impossible to reach 100 percent efficiency because there will always be some heat loss through moisture. However, the amount of heat absorbed by the coil and the amount lost through the shell can be controlled by careful design and construction.
| WHERE THE HEAT GOES |
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These thermal fluid heat transfer systems serve numerous industries and applications. Some applications where they have been used are as follows:
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| Aircraft Runways |
| Air Heaters |
| Asphalt Plants |
| Autoclaves |
| Bridges |
| Building Heat |
| Calendar Rolls |
| Concrete Curing |
| Drum Dryers |
| Drying Hoods |
| Evaporators |
| Green Houses |
| Injection Molding |
| Kilns |
| Process Tanks |
| Turbine Gas Heaters |
| Vacuum Extractors |
| Vaporizers |
| Vegetable Oil Fryers |
| Water Heaters | |
Examples of Heaters by Industry:
Petrochemical Industry: 2 x 5-million Btu/hour helical coil thermal fluid heaters located in the Gulf of Mexico. They are used to reduce viscosity of recovered crude for separation of water, heat glycol solution in a reboiler to remove water from gases, and heat amine solution in a reboiler to remove CO2 and sulfur from gases.
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Power Generation Industry: This electric generating station uses a thermal fluid system to heat natural gas from 50 to 115 deg F. Natural gas fuels the turbine engines that produce electricity. Heating the gas prevents ice formation when its pressure is reduced for the engines. Ice causes numerous problems such as clogging fuel lines and freezing control valves. Even small ice particles in the fuel can cause extensive damage to turbine engines. The system consists of an 11.7 million Btu/hour heater, a heat exchanger, an expansion tank, a pump system, and a control panel. The thermal fluid is a non-flammable mixture of water and ethylene glycol. It is heated to 300 deg F and passes through the heat exchanger where the natural gas is heated.
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Gas Processing Industry: Two thermal fluid heaters heat a mixture of glycol and water to a temperature of 190 deg F. The heated mixture circulates through vaporizers that convert LNG (Liquefied Natural Gas) to pipeline quality natural gas. Each of the two heaters can bring the circulating glycol-water mixture to temperature in ten minutes and can vaporize 66 million standard cubic feet per day. Each heater has a 60 million Btu/hour low NOx burner. They have recovery economizers for higher efficiency and reduced flue gas temperatures.
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Food Processing Industry: This facility uses 3-pass heaters to make malt. They heat thermal fluid pumped through heat exchangers to heat air that dries the malt. The air is heated to about 180 deg F and passes through soaked barley, converting it to malt. The 3-pass design is very energy efficient. The heater at this plant outputs 21 million Btu/hour, with an efficiency of 86% LHV, while one at a sister plant outputs 32 million Btu/hour and its economizer boosts efficiency to 93% LHV. The company processes barley into malt for use worldwide in beer, distilled liquor, cereal, and other foods.
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Wood Processing Industry: The world's leading producer of laminated joists, uses thermal fluid heaters to heat presses that laminate wood components of their joists. One facility uses 2 x 6.5 million Btu/hour heaters, while a sister facility uses 1 x 6.5 million Btu/hour heater. All three heaters are helical coil designs. The heaters have fully modulating burners, with high turn-down ratios, to allow for widely varying loads. The temperature of the thermal fluid at the outlet of each heater is 487 deg F. Duplex pump skids were also supplied, with piping and filters.
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Furniture Industry: This furniture plant located in North Carolina uses a 1.4 million Btu/hour thermal fluid heater. It heats presses that produce wood veneers for their bedroom furniture. The heater has a double-wound helical coil made to ASME code. It has an outlet temperature of 450 deg F. The heater is equipped with two independent pumps for circulating thermal fluid. One circulates fluid through the top platen of the press, while the other circulates fluid through the bottom platen. The temperatures of the top and bottom platens are controlled independently. The control panel is a UL-approved, Type 12 enclosure.
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Marine Vessels: These heaters are packaged thermal fluid heaters for use on marine vessels, such as barges, tankers and other workboats. They meet U.S. Coast Guard specifications. And they are certified by ABS (American Bureau of Shipping), when requested by the customer. Heaters are available in both horizontal and vertical configurations. Rated thermal outputs range from 1 to 20 million Btu/hour. Shipboard equipment is in a much more demanding environment than would be experienced in land-based facilities. This equipment is designed to withstand the stresses produced by the constant pounding and vibration in normal operation. Moreover, they can take the punishment produced in ocean storms with 30 foot waves. They can be designed to fit extremely limited space. They are designed around a helical coil that meets ASME code, and it carries a 5-year warranty.
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Printing Industry: This thermal fluid heater is used in the printing industry. It is a helical coil heater with an output of 9.4 million Btu/hour. The heater features two heat exchangers. One is for preheating combustion air to the burner, while the other is for preheating thermal fluid before it enters the helical coil. The two exchangers increase the heater's efficiency to 91.5% LHV. Both exchangers are mounted in the heater's exhaust stack. It was designed with horizontally mounted exhaust stack and heat exchangers. This allows the fully assembled heater to fit the customer's limited space requirement. It also has the added benefit of allowing the heater's shell to support the weight of both heat exchangers.
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