Say the word and you'll be free.
Say the word and be like me.

("The Word," by the Beatles, 1965)

PTOA Segment 21: Where Do We Go From Here?

Chemical Reactions: The conversion of reactants into products by breaking and rearranging the bonds between atoms.

Cooling Water Towers: An example of temperature-decreasing process industry equipment; the function of the tower is crucial to providing the "cooling water utility" to the shell and tube heat exchangers in the process area that use it for the coolant.

A cooling tower changes hot water into cold water primarily by removing The Heat of Vaporization from a small portion of the circulating water.

Direct Heat Transfer:   The transfer of thermal energy (aka heat) from a hot process stream into a colder process stream while the two streams are in contact with each other.

Fired Heater:  An example of temperature-increasing process industry equipment; a fired heater is installed where absolutely necessary to make certain that a target process temperature is attained before the process stream flows into the next piece of processing equipment.

Heat: Thermal energy. A powerful form of flowing energy related to changes in temperature.

Heat Transfer: The transfer of thermal energy from a hotter process stream into a colder process stream (and never the other way around).

Indirect Heat Transfer: The transfer of thermal energy between two process streams accomplished through a metal barrier that prevents the two flows from directly mingling with each other.

Phase Changes/Physical Changes (of matter): Melting, boiling, condensing, freezing; these are changes in the physical state of stuff caused by a change in temperature.

Shell and Tube Heat Exchanger:  A piece of temperature-changing process industry equipment that conserves thermal energy by indirectly transferring the heat from a hot process stream into a colder process stream.

Temperature-Changing Equipment:  A piece of process industry equipment that raises or lowers a process stream temperature.

Temperature-changing process industry equipment is specifically designed into an industrial process to change the process variable "Temperature" as needed for successful conversion of feedstock into desired products.

 

PTOA Segment 22: I Want to Take You Higher

Burners:  Hardware components in a fired heater that promote even flame distribution and the burning of fuel gas (which can be natural gas) with the oxygen in air.

The burners have air registers that control the flowrate of air.

Combustion Products:  The gas and vapor products that result from burning the hydrocarbons that make up fuel gas with oxygen (see definition of Fuel Gas below).

No matter which hydrocarbon is used for fuel gas, the products made from the combustion reaction are water vapor (H20), carbon dioxide (CO2), and carbon monoxide (CO). Heat is also generated from the combustion reaction.

Carbon monoxide is a sign of incomplete combustion and contributes to global warming.

Some of the nitrogen in the air used for combustion turns into oxides of nitrogen (NO and NO2) which contribute to smog.

The combustion reaction is completed in the firebox.

The combustion products that flow into the stack are often called "flue gases."

Draft: The crucial upward flow of combustion products through the firebox that prevents a stagnant buildup of combustion products, fuel, and air. Draft flowrate is controlled by the damper in the chimney.

Firebox: The main cavity of the fired heater that is lined with refractory and includes the burners, heater tubes, radiant section (where radiant heat transfer takes place) and the convection section (where convection heat transfer takes place).

The combustion of fuel gas and generation of combustion products and heat take place in the firebox.

Fuel gas: Fuel gas is made of hydrocarbons which are molecules with hydrogen and carbon.

The naturally gaseous fuels used for industrial combustion are:

• Natural gas=Methane (CH4)
• Ethane (C2H6)
• Propane (C3H8)

Butane and heavier hydrocarbons may be use as fuel gas as long as they are in a gaseous phase prior to being charged to the burners.

The heat generated from the combustion of hydrocarbon fuel gas is used to indirectly heat process fluids that flow in the firebox tubes.

Furnace: Smaller fired heaters are sometimes called furnaces. Their tag name would start with an "F" instead of an "H" on a PFD or P&ID.

Heater Tubes: The tubes that line the walls of a firebox and through which the process fluid that needs to be heated to a target temperature flow.

(Heater Tube) Pass:  A pass through a fired heater is completed when the process fluid flows from one side of the firebox to the other through the length of a heater tube.

After completing a pass through the heater, the process stream makes a u-turn and enters the firebox again to make another pass through the firebox.

Ergo, the number of passes in a firebox gives an approximation of how tall the fired heater is.

Refractory: The heat resistant material that lines the interior of a fired heater or other structure in which combustion takes place.

When installed, refractory must be cured like cement; temperatures are gradually raised until all the moisture has evaporated. Cracks in refractory are revealed as hot spots on the exterior of a fired heater.

Stack: The chimney extension of a fired heater which creates draft, the upward flow of flue gases.The stack easily identifies fired heaters in a processing complex.

The pressure in the stack is less than atmospheric pressure and must be measured with an instrument that can measure a vacuum.

A vacuum is a pressure that is less than the ambient atmospheric pressure... a negative pressure.

Creating a vacuum in the stack of a fired heater is one of the important uses of vacuum pressure in industrial processing.

 

PTOA Segment 23: More Hot Stuff: Uses of Steam

Boiler: Process industry equipment that changes the phase of BFW into saturated steam.

The PTOA classifies boilers as temperature-increasing process industry equipment specifically because the uses of steam include indirectly transferring heat into a process stream via a reboiler or by steam tracing.

(Steam or Electric) Heat Tracing: Steam lines or electrically lined blankets that are wrapped around industrial-sized pipes and valves for the purpose of  indirectly transferring heat into the process fluid that flows through them.

Ergo, heat tracing is used for freeze prevention and is turned off in the summer months and turned on in the winter months.

Inert (atmosphere): An atmosphere that cannot support combustion or reactivity due to the limited presence of a fuel source or chemically reactive component.

Kettle-Type Reboiler: A type of shell and tube heat exchanger that uses steam flowing through a U-tube bundle to indirectly heat up a process stream and separate the light components out of the stream via vaporization.

The vapors from the process stream return to a tower that is performing a physical separation by distillation.

The liquid of the process stream being heated is usually the desired liquid product from the process.

Steam: Water in the form of a vapor. Steam has much more internal energy than water because energy must be absorbed to change from a liquid into a vapor or gas.

(Steam) Strippers: Strippers are long, small-diameter towers that remove impurities from a process stream by stripping the impurities out.

Steam stripping is a physical separation of components in a process stream (as opposed to a chemical separation).

Successful stripping requires the hot steam to enter at the lower part of the tower and cold process stream to enter near the top. Strippers will be covered in future PTOA segments that feature Separating Systems.

Steam Turbines: A piece of industrial equipment in which a rotor spins due to the controlled expansion of superheated steam into a form of steam that is still superheated but with less temperature and pressure.

When coupled to the shaft of a compressor or generator, steam turbines can be used as variable speed drivers because the rate of expansion... ergo, the rate of rotation... can be controlled with a device called "a governor."

 

©2015 PTOA Segment 00051
PTOA Process Industry Jargon Recap 2-1

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