Hot in...so hot in here!   So hot in...hot...oh!

("Hot in Herre," by Nelly et. al., 2002)

 

SUMMARIZING THE WAYS
THAT PROCESS TEMPERATURES CAN INCREASE

PTOA Readers and Students have learned the following ways that industrial process temperatures can be increased.

And believe Your Mentor...it can get so hot in the industrial processes!

Exothermic chemical reactions change the chemical structure of process streams and release energy into the process while doing so. The heat released goes directly into the process stream (which is the reactor effluent).

Fired heaters indirectly heat process streams to the exact target temperature that the process must attain before continuing. The thermal energy of the combustion products made from fuel gas and oxygen indirectly heat the process fluid while it is flowing through the heater tubes.

Steam made in steam boilers is used to indirectly heat process streams...like in reboilers. The steam is generated by indirectly heating BFW with hot combustion gases while it flows through boiler tubes.

The Heat of Condensation releases heat when a vapor or gas condenses into a liquid.

The Heat of Condensation is hard to recognize for a real good reason: the liquid that is condensed from the vapor/gas will be at a cooler temperature. The "hidden" heat that is released during the condensation process goes into the surrounding atmosphere or vapor spaces of a container.

PTOA Readers and Students will learn more about the Heat of Condensation during future PTOA segments covering Fin Fan Condensers and Separating Processes. So don't fret about it now.

Oh yeah:

Technically speaking, steam tracing used to externally maintain a process stream temperature above a minimum is also indirectly adding heat into a process stream.

Electrical tracing can also be applied  externally to pipes, valves, and flanges, etc. to maintain process temperatures above a minimum.

In general...and until the renewable sources of energy become more economical to use...the use of electricity to heat up industrial-sized process streams is too expensive.

Otherwise stated, the  industrial-sized electrical equivalent of a fired heater is not currently common process industry equipment.

Thus the main ways that process stream temperatures will be increased are limited to:

• fired heaters.
• steam from steam boilers used for indirect heating.
• exothermic chemical reactions.

 

KNOW WHERE THE HEAT SOURCES ORIGINATE

Do you know where the sources of heat originate in your home?

You should because those locations could start a fire that could burn down your home and worse, harm your family.

The following common household features ignite fuel to generate heat:

• a fireplace.
• a gas kitchen range (natural gas or propane).
• a gas water heater (natural gas or propane).
• a gas boiler.
• a gas clothes dryer.

The following electrical appliances annually cause household fires:

• overheated clothes irons.
• overheated hot water heaters.
• overloaded electrical wiring.
• lint-filled electric clothes dryers.
• unattended electric stove tops with nearby fuel sources.

Likewise, Process Operators must be aware of the sources that can increase process temperatures in the processing complex.

In the event a process stream temperature is too high and climbing, the generation of the heat source is the first place to start trouble-shooting.

 

WHAT'S NEXT?

This PTOA segment concludes the study of increasing process temperatures.

The next PTOA segments are about  process equipment that PTOA Readers and Students have already seen on P&IDs: Shell and Tube Heat Exchangers.

Shell and Tube Heat Exchangers indirectly swap heat between hot and cold process streams. One process stream enters the Shell and Tube Exchanger hot and leaves colder while the other enters the Shell and Tube Exchanger cold and leaves hotter.

So technically speaking, a Shell and Tube Heat Exchanger can be added to the list of temperature-increasing equipment...and temperature-decreasing equipment!

After learning about Shell and Tube Heat Exchangers basics, PTOA Readers and Students will learn about processing equipment that is specifically designed to decrease process temperatures.

 

TAKE HOME MESSAGES: PTOA Readers and Students reviewed the ways that a process temperature can be increased:

• indirectly by temperature-increasing equipment (fired heaters and steam made from boilers).
• directly by exothermic chemical reactions and physical phase changes into "more-bound-together" state.  

At home and at work, recognizing when a temperature is too high is important and knowing where the sources of heat originate is the first place to start troubleshooting. 

©2015 PTOA Segment 00029
Process Industry Temperature Changing Equipment

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