REPLACING FLUIDS IN HEAT TRANSFERS

The fluids in heat transfers are crucial to many of its processes. Ensuring the safe, ongoing operation of these systems depend to a great extent on the fluid, during the regular operation and particularly during the systems startups and shutdowns. To ensure a smooth shutdown every time, as well as a reliable startup without damage, follow these guidelines.  

Fluids in Heat Transfers, the Samples and Analysis

Fluid samples should always be sent to qualified laboratories, which specialize in analyzing the fluids in heat transfers. It is advisable to take samples both after draining and filling a system to provide constant monitoring for the fluid of the heat transfer system. A quick-disconnect valve can speed up the unloading and loading process.  
 

Fluid Flow Characteristics

Industrial Procedures for Startup of a Heat Transfer System

Step #1 System Flush:

To accomplish a required flush of the fluids in heat transfers, fill the system to 80% capacity with the flushing fluid. See below for the fill instructions, and then run at 204°C or 400°F for an eight-hour period. It is critical to utilize the right flushing fluid in your system, whether that system is setup for synthetic or hot oil, your supplier can assist in choosing the right flushing fluid for the system you are flushing. Then, flush the fluid and proceed to Step #2.

Step #2 System Fill:

Charge the systemthrough system low points with fluids in heat transfers. The principle objective in startup of the system should be removing additional trapped light-end (fluids that have a lower boiling point than that of fluids in heat transfers) fluids or moisture. To remove residues, during startup run the fluids through the system expansion tank. Light-ends or moisture escaping could cause a spike in the system pressure or small puffs of steam or vapor as it leaves the vent from the expansion tank.

Step #3 System Start:

Always start the pump before turning on the heater, this ensures fluid circulation and a turbulent fluid flow prior to heating. At the onset of fluid circulation, follow these steps to bring up the system to desired temperature for operation:

Ø  Increase heat at the rate of 1° Fahrenheit or less per minute up to 200°F or 930°C. For one cycle.

Ø  Increase heat at the rate of 1° Fahrenheit or less per minute up to 230°F or 110°C. For one cycle.
Ø  Increase heat at the rate of 1° Fahrenheit or less per minute up to 260°F or 127°C. For one cycle.
Ø  Increase heat at the rate of 1° Fahrenheit or less per minute up to 300°F or 149°C. For one cycle.
Ø  Increase the heat at the rate of 50° Fahrenheit per minute until desired operation temperature is attained for one cycle under close observation.

NOTE: 

Ensure that you allow a full cycle for each step before moving on. One complete cycle is determined by pump output and the system’s total volume. When excessive amounts of vapor are generated at a specific temperature, continue at that temperature until vapor venting declines. Since water’s boiling point is 212°F or 100°C, this is where you can expect the heaviest venting to occur and the temperatures in step #two should be slowly increased until it has passed 212°F or 100°C, that will permit excess moisture to vent.

Shutting Down the System