13-14 Flashcards
this system provides the means to measure, compare, analyze and correct one or more process variables
instrument system
these are the current, varying process conditions which are monitored and controlled.
process variables
Name the 5 commonly controlled variables
temperature (thermocouple)
pressure (d/p cell)
level
flow (orifice disk)
analytical data - pH meters, Viscosity meters etc
devices in direct contact with a process variable that needs to be measured and transmit a signal or value to another instrument
sensors
a collection of instruments that work together to monitor and automatically control a process
control loop
in a control loop a process variable is measured by a ______ which is converted by a ______ or _________ to a proportional pneumatic or electronic signal that represents the process.
sensor, transducer, transmitter
some different process variables that sensors are used to monitor may include
temperature, vibrations, speed, pressure, and UV light
this receives a signal from a transducer and transmits it to the controller
transmitter
these are devices that ensure a value is positioned properly in reference to the signal from the controller
positioners
are electronic, pneumatic, or hydraulic devices that move control equipment, typically a valve of some sort. They can be designed for linear or rotary motion.
actuators
describe the 3 states of hydrocarbons
< 4 carbon atoms typically gas
5 - 19 carbon atoms typically liquid
> 20 carbon atoms they are solids
***@ ambient temp and pressure
is the process by which a liquid mixture is separated using boiling points into two or more substances or components (each having their own boiling point)
distillation
the boiling point of any mixture depends on the bp of individual _______ in the mixture, the ________ of each in the mixture, and the _____ exerted on the mixture.
hydrocarbons, proportion, pressure
is a process where a mixture is fed into a system and different product streams are continuously removed
continuous distillation
when process feed or charge stream contains three or more elements to be distilled/seperated; is typically the initial distillation which happens in refineries
multi-component
when process flow contains two elements to be distilled/separated; is typically the second distillation column in refineries where products are pulled and quality specifications must be met
binary
a curve indicated on a graph of the pressure developed by pure component liquids are various temperatures
vapor pressure curve
the heavy ends material collected at the bottom of the distillation column will move down the column as a liquid and usually has the highest boiling temperature
tower bottoms
the entry point or feed tray
flash zone
places along the tower within a specific temperature range from which product is removed; used when more than two product streams result from the process, such as crude oil distillation
cut points
boiling occurs when the temperature is __________ or when the pressure is _________
increased, lowered
standards used to measure the heaviness or density of a hydrocarbon
API gravities
a table that explains or defines all the information on a drawing, may include symbols, abbreviations, numbers, tolerances, etc
legend
shows the entire process and how the different systems within the unit relate to each other. A simpler drawing
block flow diagram (BFD)
