Heat Transfer Fluid Replacement Precautions

Play an AI-generated podcast conversation about this lesson

What is the main difference between a hot oil system and a hot water heating system?

The fluid chosen in a hot oil system has a higher boiling point than water in a hot water heating system. (correct)

Hot oil systems have higher vapor pressure than hot water heating systems.

Hot oil systems use water as the thermal fluid while hot water heating systems use oil.

Hot oil systems operate at a lower temperature than hot water heating systems.

Why are heat transfer fluids like hot oils preferred in high-temperature applications?

Due to their low energy efficiency.

Because they have high vapor pressure.

As they have lower vapor pressure compared to steam. (correct)

To maintain high pressures in the system.

What issue was faced with the original oils used in heat transfer fluids when the temperature regularly exceeded the stable temperature?

They maintained their stable properties.

They had higher energy efficiency.

They broke down as they became partially oxidized and unstable. (correct)

They became more thermally stable.

Why are heat exchangers used in hot oil systems?

To transfer the heat of oil to other fluids. Signup and view all the answers

How do hot oil systems compare to steam systems under jurisdictional regulations?

Hot oil systems are registered at a lower level than equivalent steam systems due to lower vapor pressure. Signup and view all the answers

What is a primary reason for using hot oils as heat transfer fluids over other options?

Their higher energy efficiency and heat transfer rates initially. Signup and view all the answers

Why are hot oil systems preferred over steam in many applications?

Hot oil systems operate at atmospheric or higher pressures. Signup and view all the answers

What is the main purpose of the expansion tank in a heat transfer fluid system?

To allow the heat transfer fluid to expand when heated or contract when cooled. Signup and view all the answers

Why do hot oil systems usually use centrifugal pumps?

Availability of higher flow rates for enhanced heat transfer. Signup and view all the answers

What is a disadvantage of using vapor phase heat transfer systems over liquid phase systems?

Vapor phase systems have a narrower temperature range for control. Signup and view all the answers

Why do contaminants pose a problem in heat transfer fluid systems?

Contaminants can lead to blockages, surface spoilage, and impede heat transfer. Signup and view all the answers

What effect does overheating have on heat transfer fluids?

Overheating can degrade the fluid and impede heat transfer. Signup and view all the answers

What equipment allows for expansion and contraction of the hot oil in liquid thermal systems?

Expansion tank Signup and view all the answers

What is the primary consideration for selecting the type of HTF (heat transfer fluid) for a process?

The process temperature requirements Signup and view all the answers

What issue might arise if an expansion tank in a heat transfer system is not monitored regularly?

A leak might go undetected Signup and view all the answers

Why are centrifugal pumps preferred over gear pumps in liquid thermal systems?

Availability of higher flow rates Signup and view all the answers

What type of pump is commonly used in liquid thermal systems?

Centrifugal pump Signup and view all the answers

Why are the circulating pumps in liquid thermal systems often water-cooled?

Due to the high temperature of the thermal fluid Signup and view all the answers

What is the major equipment in liquid thermal systems that supplies the distribution system?

Pump Signup and view all the answers

What is the consequence of not cleaning the system and removing all traces of old heat transfer fluid before recharging with fresh fluid?

Premature degradation of the new fluid Signup and view all the answers

In heat transfer fluid systems, what is a potential hazard associated with leaks at high temperatures?

Production of a potentially flammable mist Signup and view all the answers

Why are centrifugal pumps preferred in liquid thermal systems over gear pumps?

Higher flow rates for enhanced heat transfer Signup and view all the answers

What is the typical efficiency range for radiant heaters used in heat transfer fluid systems?

40-50% Signup and view all the answers

What is a key advantage of convection heaters over radiant heaters in HTF systems?

Higher efficiency Signup and view all the answers

Why are combination radiant and convection heaters commonly applied in larger units?

Favorable efficiency Signup and view all the answers

In a typical up-draft fired heater design, where are the convection tube sections usually located?

In the breeching Signup and view all the answers

How are gas burners typically positioned in a horizontal rectangular heater in a direct heater design?

"Along a center line from front to back on the floor" Signup and view all the answers

What is the purpose of having a concrete dike surrounding the foundation of the fired heater?

To prevent hot oil from spreading beyond the immediate area in case of tube rupture Signup and view all the answers

Why are protective devices necessary in a hot oil system?

To reduce the risk of fire hazards Signup and view all the answers

What does a low hot oil flow indicating device aim to prevent?

Tube failure due to overheating Signup and view all the answers

Why is it recommended to keep the expansion tank level between 2⁄3 and 3⁄4 full?

To minimize fluid oxidation inside the tank Signup and view all the answers

What is the purpose of having an emergency shutdown device/switch in a hot oil system?

To manually shut down the plant in dangerous situations Signup and view all the answers

Why are two pumps usually installed in a hot oil system?

To maintain standby pump at operating temperature Signup and view all the answers

What happens if the expansion tank level is too high in a hot oil system?

Risk of fluid oxidation Signup and view all the answers

Why should a small amount of hot oil flow backwards through the standby pump in a hot oil system?

To increase mechanical seal lifespan Signup and view all the answers

What is the function of a high stack temperature indicator in a hot oil system?

To detect tube failure and combustion hazards Signup and view all the answers

Why is a pressure/safety relief valve placed downstream of the heater in a hot oil system?

To release excess pressure and ensure safety Signup and view all the answers