chapter 12 Flashcards
What is the term for a reactor that accepts a steady flow of raw materials, solvents, catalysts, and recycle streams?
Continuous reactor
Repeating-cycle reactor
answer A
What is a type of continuous reactor used by wastewater plants to remove harmful products before discharging clean water?
Furnaces
Digesters
answer B
Besides being used to absorb excess heat, what is the function of a diluent such as nitrogen in a gas phase reactor?
To dilute reactants to a safe concentration
To decrease residence time
answer A
The recipes, operating conditions, and sizes of continuous reactors are ________ laboratory experiments.
much different from
rarely any different from
answer A
When a product stream contains unreacted raw material along with product, what happens to the unreacted material?
It is filtered off and discarded.
it is burned off
It is recycled and turned back
answer c
How can plants slow the reaction down and limit the amount of heat generated by reactions that might proceed too quickly and generate heat too rapidly?
By diluting the raw materials in a solvent
By changing to a batch reaction approach
answer A
Steady temperature, pressure, level, and feed flow in a continuous reactor during normal operation should produce what result?
Satisfactory product stream composition about 50% of the time
A consistent product stream composition
answer B
What do process technicians in a continuous reactor operation do routinely during their shift?
Collect and analyze reactor samples.
Perform emergency shutdowns.
answer A
In ________ continuous-flow reactions, redundant (backup) temperature and pressure instruments are required for safety.
endothermic
exothermic
answer B
What may happen if the reactor cools off or depressurizes?
The reaction may stop.
it can possibly explode
answer A
What may result if catalyst ages and deactivates over time?
Performance may degrade.
No action is required
answer A
How does continuous reactor startup compare with normal operations?
They require more monitoring but less sampling.
They require more monitoring and sampling.
answer B
Why does the solvent ratio start out relatively high during startup?
To dilute the reaction mixture and maximize the heat released
To dilute the reaction mixture and limit the heat rel
eased
answer B
What can occur in a continuous reactor when unreacted raw material concentration rises above a safe level?
Off-spec product
A runaway reaction
answer A
When is the potential for pooling highest?
When there are no unreacted materials present
When starting up or cooling down a reactor
answer B
Besides following established procedures, what can minimize the process technician’s potential for exposure during sampling?
Donning proper PPE
Using robotic hands
answer A
Which would improve conversion in a fixed bed reactor?
Increasing feed rate
decreasing feed rate
answer A
Which would improve conversion in a stirred tank reactor operating in continuous mode?
increasing level
decreasing level
answer A
Which best describes a tubular reactor?
A reactor in which the catalyst is constantly moving and being regenerated.
A jacketed pipe or multi-tube in shell reactor
answer B
