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Terms in this set (53)
Reactive Hazards: Dangers of Uncontrolled Chemical Reactions
According to the video, which historical accident spurred Congress to require OSHA and the EPA to implement regulations for process safety?
(T or F?)Over 90% of serious reactive chemical accidents involve hazards that hvae already been described in publicly available literature
Which of the following sources are included in initial screening methods for reactive chemistry?
A) Sax's Dangerous Properties of Industrial Materials
B) Bretherick's Handbook of Reactive Chemicals
C) Lee's Loss Prevention in the Process Industries
D) Essential Practices for Managing Chemical Reactivity
E) All of the above
All of the above
(T or F?) Initial screening methods are the only source for identifying reactive hazards.
(T or F?) Specialized testing provides useful information for understanding reactive chemical systems performing safe scale-up.
(T or F?) It is important to review potential process changes in reactive chemical processes.
Which of the following upset scenarios could potentially lead to a runaway reaction?
A) Incorrect mixing of raw materials
B) Add reactants in wrong order
C) Add the wrong material to the reactor
D) all of the above
E) none of the above
all of the above
(T or F?) Based on the CSB report from 2002 on reactive hazard investigation, more than half of reported incidents involved substances that were not covered by current federal process safety regulations.
In the Synthron accident what changes were made to the process?
-Increased batch size by 12%
-added the extra monomer at one time in the first step
In the BP accident, what happened to the pressure relief lines in the waste tank?
They were clogged due to the excess addition of polymer; failed to relieve the accumulation of pressure in the tank; and became ineffective after the pressure sensor was sealed off
In the BP accident, it was known that the hot molten plastic could react to produce gas, but:
this information was not successfully communicated to workers, and was not incorporated into the process design
(T or F?) In the MFG accident, highly toxic vapors were released into a residential community due to an inappropriately sized pressure safety valve
(T or F?) MFG performed a trial batch in a 30 gallon reactor where all of the chemicals and catalyst were combined at one time.
(T or F?) The lab scale test data was properly used to determine the heat removal limitation of the production reactor compared to the lab scale reactor.
The CSB gives the following advice in order to prevent accidents related to reactive chemical hazards:
-Companies should identify and thoroughly evaluate reactive hazards in their processes
- appropriate emergency pressure relief systems and other design safeguards should be in place
- facilities need to plan for possible accidents including evacuation drills and emergency response exercises
In order to safely manage reactive chemical hazards, it is necessary to:
- understand the chemistry under design conditions
-understand the chemistry under all foreseeable abnormal conditions
-perform initial desktop screening
-perform lab experiments to quantify heat and gas generate rates
(T or F?) Technology and management systems exist to perform reactive chemical processes safely.
Rupture of a Nitroaniline Reactor
Overpressures of _____ psi can break windows.
(T or F?) It is important to understand and quantify the reaction chemistry for a given process.
(T or F?) The sequential steps of a chemical process are not important and do not affect the chemistry.
Which of the following is not a major objective of an incident investigation?
Identify total amount of damage sustained
(T or F?) Manufacturing a product for several decades without an incident indicates that there is no potential for a future accident.
A runaway reaction occurs when heat:
generated exceeds heat that can be removed
(T or F?) The temperature of no return can be calculated for a given vessel, operating conditions and recipe.
The temperature of no return designates:
the temperature at which a runaway reaction cannot be prevented
(T or F?) As an engineer, I should provide management the necessary data to make informed decisions regarding safety of personnel and property.
(T or F?) The moles of gas produced per mole of reactant cannot be calculated prior to scale-up.
(T or F?) Pressure relief systems require proper design and routine preventative maintenance to ensure performance.
(T or F?) When the temperature of contents in a vessel increases above the point of no return a runaway reaction is unavoidable.
For the nitroanaline relief system design, the reccomended configuration by the CSB was:
Vessel --> Rupture disk --> Pressure gauge --> pressure safety valve
(T or F?) Safety interlocks can be used to prevent accidents, and they should provide multiple layers of protection.
Preventative methods for industrial accidents include:
- Management of change (MOC)
- Process Hazard Analysis (PHA)
- Pre-Startup Safety Review (PSSR)
- Mechanical Integrity (MI)
- Proper Training
Rupture of a Nitroaniline Reactor
Kinetics indicate that the reaction rate was mostly dependent on ONCB or NH3?
Rupture of a Nitroaniline Reactor
The autoclave reactor was overcharged with _____ and was undercharged with _____ using a _____ than normal solution.
Options: NH3, ONCB, weaker, stronger
ONCB, NH3, weaker
Experiments for Runaway Reactions and Vent Sizing
(T or F?) Pressure relief systems can be successfully designed for reactive chemical systems based on appropriate low phi-factor experimental data.
(T or F?) The required vent size is determined using an energy balance on the reactor where the rate of energy removed must be greater than or equal to the rate of energy generated by the reaction.
(T or F?) The Advanced Reactive System Screening Tool (ARSTT) is useful tool for screening potentially reactive chemicals and obtaining data necessary for relief vent sizing.
What are the three runaway reaction classes?
vapor, gassy, and hybrid
For a vapor system, the set pressure is recommended to be what compared to the design pressure?
the set pressure should be below the design pressure
The methanol and acetic anhydride system is an example of a _____ system.
Vapor, gassy or hybrid?
For a vapor system, the required vent area is dependent on the:
temperature rise rate
For a gassy system, the required vent area is dependent on the:
pressure rise rate
For a hybrid system, the required vent are is dependent on the:
temperature and pressure rise rates
(T or F?) Relief systems are designed to prevent over pressurization of a vessel.
For open system testing, the first experiment should be performed at the:
Maximum allowable accumulated pressure (MAAP)
The maximum allowable accumulated pressure (MAAP) is equal to:
1.1 times the maximum allowable working pressure (MAWP)
(T or F?) It is conservative and appropriate to assume that a vapor system is foamy unless an experiment to the contrary is performed.
For open system testing, the second experiment should be performed at what pressure?
Relief set pressure
For open system testing, the second test is performed in order to determine if the system is what?
Tempered, foamy, or hazardous?
Hydrogen peroxide is an example of a _____ system.
The pressure of non-condensable gas generated during an ARSST experiment can be calculated by subtracting:
the initial pressure from the final pressure at the same reference temperature
(T or F?) The driving force for flow in the vent depends on whether the velocity is greater than or less than the speed of sound (i.e. critical (choked) or sub-critical flow).
Dr. Fauske's screening equation is based on physical properties of:
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