Last_year_exam Flashcards
PLASTIC not plasma
for what is not a conductor
Accuracy of reading
= 2.5%
What is done for a sampling conditioning probe?
Dilution & Filtering
What is regular maintenance for a coriollis meter?
Requires additional cleaning if dirty process
Where would you put orifice taps on a steam line?
Horizontal and below
What does the surface area of coal improve when crushed?
Combustion
What is annealing?
Relieves internal stress in metals
Water w/ Natural gas burning is a
Chemical reaction
Question #3 on Test.
Requires minimum voltage (Analog)
O2 in a chem. Reaction is…?
Oxydant
DP Trx how does it measure?
Infers the height
What benefits in Cascade control?
The inner loop Helps stop manipulated variable variances
PI output =
?
What does a catalyst do?
Speeds up a chemical reaction
Advantage of a grab sample?
Cheap/Inexpensive
Selective control
low
What is cascade control?
Uses output of primary controller to manipulate SP of secondary controller
Pure H2O benefits from what measurement?
Conductivity
What controller responds to setpoint & load changes?
D (derivative)
For a liquid flow process what should the controller settings be?
TA: 0.5, 10
What type of capacitance probe should be used in a conductive solution?
Insulated probe
% of reading
Gauge
What is a polar covalent bond?
Unequal sharing of 2 metals
What is positive displacement?
Gas remover : overspeed
Insitu VS. Extractive sampling?
Insitu is cheaper
Self regulating
Process comes back on its own without control intervention
Characteristic of SMART Trx is?
Linearity
Bonding is used to
reduce electrostatic, eliminate zero shift
Any petro location is a what?
Hazardous location
When an atom lose/gains an electron?
LOSES –> atom becomes “+” oxidation occurs GAINS –> atom becomes “-“ reduction occurs LEO the lion goes GER
What is the graph for?
PI
What is the sum of error?
All possible errors
Derivative responds to?
SP and load changes
Magnetic law? Who invented?
FARADAY
What is the max loop resistance (ohms)?
600 ohm
What is Doppler flow measurement?
Change in frequency and time
Valve action
Reverse for both
What is lag?
Deadtime
What is the difference between coal and CH4 combustion?
Coal combustion does not produce H2O C + O2 –> CO2 CH4 + O2 –> CO2 + H2O
What is an I/P?
Transducer (Current mA, to, Pressure (PSI, kPa, etc))
Why is pH hard to measure?
Logarithmic scale Deadtime Hard to control Non linear Output 10x Difference
I/P current UP?
Reverse acting
How does ultrasonic level detection work?
Transmits a signal down to fluid and amount of time it takes to come back is inversely proportional to level.
How does a load cell work?
More resistance, more load
Pure water benefits from
conductivity measurement
What is the flow proportionality for vortex meters?
Vortices form is directly proportional to the flow rate
What is measured during a Rockwell hardness test?
Indentation
Non
Linear
Resolution calc. for DAC/ADC Ex. 4 -20 mA input with 10 bits
Res. = SPAN/STEP = (20mA – 4mA)/(2^10 1) = 15.6mA/step
What does phase lag do when gain decreases in a first order process?
Phase lag increases, gain decreases
Easiest way to calibrate a nuke meter?
Close shutter for full level 50% lvl (2nd Cal point) G.m down vessel wall between wall and detector. Output from detectors adjusted
How is a hydrostatic test performed?
With H2O
What is opacity?
Absorption of light in a solution
Define multi capacity.‐
A combination of deadtime & first order
Why do we ground both sides of a mag meter?
To eliminate electrostatic zero voltage shifts (charges)
Mechanical property?
Ductile
What type of process is it if gain changes at different points (3)?
Non linear, multicapacity, integrating
What is this C=C-C?
Propene
How do you measure level using radar?
Electromagnetic
Wet leg
?
What is group VIIA?
Halogens
Where is a particulate filter placed?
Before the analyzer
With a 5% increase in CO & a 10% decrease in PV, what is the gain?
= RA, 0.5 gain
First order + deadtime?
ke ^ dts / 1 + ti S
What is a worldwide used analyzer?
Chilled mirror
Manual bias?
PI
Valve positioner
Cascade Valve signature
Aromatics benzene (C6H6)
pH questions
ph > 7 Basic pH
How do you determine derivative?
Is a measure of how a function changes as its input changes
__C4H10 +__ O2 —> __CO2 +__ H2O
-A = 1 in front of CO
What is measured when analyzing pH or electrical conductivity?
Measures activity of ions
Coriolis meter maintenance?
Clean and perform zero calibrations
Different gains in a process means?
Non-linear
What is kinematic viscosity equal to?
kinematic viscosity = dynamic viscosity/density
What is K Factor?
The amount of pulses per unit of volume . ex. Pulses per gallon, pulses per litre. Q = F * 60 / K
What to monitor for stack/flue gases?
CO, O2
Why is shielding used?
To correct electromagnetic interference
How is turbidity measured?
Scattering of light in a solution
Reset wind up in selective?
Happens to both controllers Cascade can be eliminated through external feedback by connecting secondary to primary
Where do you shield on an instrument loop?
At one end only. No shield in the field, at control end only
2,2 dimethyl butane
Valve positioner =
Valve signature
What is bias?
Output of the controller when no errors exist
What are the products of coal in complete combustion?
CO + O2
Q/A =
No PID controller calibration
What is CV?
The flow coefficient of a device is a relative measure of its efficiency at allowing fluid flow. It describes the relationship between the pressure drop across an orifice, valve or other assembly and the corresponding flow rate.
What state is IIA?
Solids
Linear expansion, Temp co efficient expansion distance?
14.6 mm
What is Accuracy?
Defined as the closeness with which the output of a device represents the true value of the input to that device
What is the difference between a 2 wire and 4 wire Trx?
4 wire : uses 2 wires for power and 2 for 4-20 2 wire: uses both wires for power and 4-20
Calibration procedure
Zero, the span, repeat
Formula for Calcium Chloride?
CaCl2
Q/A =
Reset windup on both controllers
Disadvantage of a grab sample?
Inaccurate / Bypass line needed
Process requiring an Extended diaphragm?
Corrosive and slurries
What is Repeatability?
When you repeatedly input an amount and always get the same output
What is molar mass?
Mass of one mole
Closed loop?
Gain —> kc * kp / 1 + kc*kp
What oxidizes in H2O?
Fe (Iron)
What is possibility?
Sum of error
What is a communication standard?
RS 485
What is radiation?
Time, shield, distance
What is traceability?
“An unbroken chain”
What does benzene look like?
?
Why are magnetic ground straps important?
Prevents stray current from passing through
Selective control:
Low select
What is concentration?
mg/5L = ppm
Bluff body?
Directly proportion to flow
An Oxygen Ax detects a 20% increase in the fuel gas, what happens to A/F ratio?
AFR (up) and CO (down)
