Equip Exam 3
include gauges, transmitters, controllers, transducers, primary elements and sensors, computers, control valves, and other types of final control elements.
1. List seven basic types of instruments found in the processing industry.
it is referred to as coking.
1. What are carbon deposits in the tubes of a furnace called?
is known as the economizer section. It uses hot combustion gasses from the burner to warm up water that enters into the boiler's upper drum.
1. What is the name of the section in a water-tube boiler that pre- heats the water?
_____ instruments-usually computers-that read incoming signal and translate it into action. They are run in three different modes: manual, automatic, or cascade. In manual mode, a human being tells the _____ what to do. In automatic mode, the _____ uses its system to adjust process variables on its own. In cascade mode, a _____ is part of a series of controllers that cumulatively make decisions on how the process variable(s) need be adjusted.
10. Describe controllers and control modes.
include dampers, air ducts that include fixed blades to conduct air flow, spuds to distribute the gas, and an igniter.
10. List the key components of a natural gas burner.
shows the connections between instrumentation and the control room panels.
10. What information is obtained from a loop diagram?
part of the convection section of the furnace. It includes a set of tubes that rest directly above the radiant section of the furnace, and receives both radiant and convection heat.
10. What is shock bank?
Starting a boiler requires the following seven steps: 1st. Fill the steam drum with water. 2nd. Start the fan. 3rd. Purge the furnace. 4th. Check the furnace for flammables. 5th. Light the burners. 6th. Bring the boiler up to pressure. 7th. Place the boiler online.
11. What are the seven major things an operator does when starting up a boiler?
shows wiring and all electrical components found in a unit, as well as rough specifications such as voltages, horsepower of electric motors, etc.
11. What information is available on electrical one-line diagrams?
the process flow.
11. What is the charge of a furnace?
wall within the furnace that separates sections of the radiant portion of the furnace. It also refers to the walls that transition from the radiant section of the furnace to the convection section.
12. Describe the bridgewall section in a furnace.
include DP cells (for both level and flow), positive displacement meters, rotometers, turbine flow meters, weir and flume devices, magnetic flow meters, ultrasonic flow meters, vortex flow meters, thermal flow meters, coriolis flow meters, direct level measurement instruments (sigh glasses, floats, displacers, probes), and indirect level measurements (pressure meters, DP cells, bubblers).
12. List the primary elements and sensors used with level and flow.
include tube rupture, loss of water flow, and flame impingement.
12. List three operating problems found in a boiler.
aka Equipment Location drawings, show the physical location of equipment as well as plant boundaries.
12. What information is contained on a plot plan drawing?
distributed control system. This is a computer that is used as the control element in a control loop.
13. Define the term DCS.
Hot air rises. This effect causes a vacuum at the bottom of the furnace (the firebox), which draws fresh air in.
13. Describe a natural-draft furnace.
Forced-draft furnaces, like forced-draft cooling towers, use fans to push air into the burners. Induced-draft furnaces pull air into the burners using a fan at the top of the furnace near the stack. Balanced-draft furnaces use a combination of these two effects.
13. Describe how forced-, induced-, and balanced-draft furnaces operate.
Block flow diagrams are simple diagrams that show how material moves from one location to another through a unit in a non-technical manner.
13. Describe the basic components of a block flow diagram.
serve the function of removing condensate from the steam system before it can cause unwanted damage.
13. What is the purpose of a steam trap?
includes symbols for all equipment, piping, and instrumentation on a unit. They show all connections and thus illustrate the function of all elements of the systems of the unit. This is an invaluable tool for an operator to learn from.
14. Examine the basic components of a P&ID and explain how it can be used by a technician to learn how to operate a process unit.
mechanical and thermostatic.
14. Name the two classes of steam traps.
aged or improperly cured refractory that has cracked or fallen out of position.
15. Define spalled refractory.
include inverted bucket and float. In an inverted bucket trap, steam collects inside of a "bucket." A valve allows gasses to escape, but keeps liquid inside of the bucket. A float type trap operates similarly to a commode; it uses a mechanical float to operate a valve that releases condensate as it builds up inside the trap.
15. Name and describe two types of mechanical steam traps.
Air flow in a furnace is critical for safety and efficiency concerns. Maintaining proper draft ensures that air and combustion gasses move through the furnace properly, and reduces the chances of impingement and hot spots.
16. Explain the importance of proper draft control in a furnace.
____ are so called because they respond to the differences in temperature between steam and condensate. The bellows style uses a set of contracting bellows to control the flow of gas. Condensate causes the bellows to open, allowing the condensate to drain out. Gas causes the bellows to close, preventing gas from escaping.
16. Name and describe a type of thermostatic steam trap.
occurs when the hangars that support the tubes break, or when excessive fouling occurs on the outside of the tubes.
17. Describe sagging or bulged tubes.
"water hammer."
17. What term is used for a condition in which slugs of water cause damage to equipment?
Boilers are very hazardous machines. Some of the hazards include steam burns, hazards of natural gas, problems with leads, instrument failures, the subtle dangers of confined space entry, issues of opening and blinding, lock out/tag out hazards, hazards of lighting burners, temperature and pressure control concerns.
18. Describe hazards associated with boiler operation.
include RTDs (resistance temperature detectors) and thermocouples.
18. List the primary elements or sensors for temperature.
is made of a heat-resistant castable, covered in high-temperature bricks.
18. The floor of the furnace is covered with what type of material?
the term referring to a boiler that has reached its target pressure.
19. Define placed on the line.
has two different metals that react differently to temperature changes. They are attached at the tip. As temperature rises, these two metals generate a low level electrical output that varies based on temperature. This output is translated into an associated temperature.
19. Describe a thermocouple and explain how it is used.
a U-shaped curve in the tubes of the convection section of the furnace.
19. Describe the return bend designs in the convection section.
a burner inside a furnace stops burning. This allows fuel to enter the furnace without burning, causing a dangerous buildup of un-combusted fuels.
2. Describe flameout.
has a flexible diaphragm that is able to sense pressure variances. By connecting the DP cell to two different points on a process line, the DP cell can detect the difference in pressure between these points.
2. Describe the operation of a DP cell.
a component that distributes fuel gas in the burner section of a boiler.
2. What is a spud?
a plant's demand for steam.
20. Define boiler load.
reduces furnace efficiency. However, excess airflow reduces the chances of fuel going un-combusted, which is more desirable than the deleterious* side effects of allowing fuel to go un-combusted.
20. Excess airflow in the furnace will have what effect?
is a thin, hook shaped metal tube that is part of a pressure sensing instrument. As pressure changes, it causes the tube to straighten out. This pulls on linkage that causes the needle on the pressure gauge to change in response.
20. Explain how a bourdon tube works.
Water tube boiler and fire tube boilers are significantly different. Fire tube boilers resemble a heat exchanger, using heated tubes to warm up a vat of water. Water-tube boilers instead circulate water between a pair of drums. The water circulates due to pressure differentiations caused by heating, and the tubes connecting the drums pass directly by the unit's burner.
3. Contrast a water-tube boiler and a fire-tube boiler.
an area of uneven heating within a furnace.
3. What is a hot spot?
is a device that detects flow rates.
3. What is a rotameter used for?
In a water-tube exchanger, warm water passes from the upper drum to the lower drum through tubes known as downcomers. Water boils in the lower drum, then the heated water and steam returns to the upper drum through riser tubes.
4. Contrast a downcomer tube with a generating, or riser, tube.
include the sensor, the transmitter, the controller, a transducer, and the final control element (usually a valve).
4. List the basic elements of a control loop.
key components include the two drums (upper and lower), the various tubes (downcomers, risers, superheated steam tubes, etc), the burner itself, the furnace, makeup water lines, the boiler stack, and the economizer section.
5. Identify the key components of a water-tube boiler, and describe the water circulation in the boiler.
are located at the top of the furnace. The shock bank is the section of the convection tubes closest to the radiant tubes, receiving both radiant and convection heat.
5. Where are the convection tubes located in a furnace?
Saturated steam is any steam that is in contact with water. Once steam leaves contact with water and its temperature is raised, it is known as superheated steam. However, sometimes this superheated-or dry-steam is considered too hot for some plant processes, so it is returned to the boiler. This process puts the superheated steam back into contact with water, causing the undesired heat to be absorbed by water. This steam is now known as desuperheated steam.
6. Contrast superheated steam, desuperheated steam, and saturated steam.
when flames from the burners directly touches metal of the furnace. This can rapidly damage metals and is not desired.
7. Describe flame impingement.
include the operation of turbines, distillation systems, reaction systems, flare systems, and extrusion systems.
7. List five operations in which steam is used.
including: Air shutters on the burners, air registers near the burners, peep holes, leaks and cracks, damaged doors and gaskets, and even extinguished burners.
8. Air enters the furnace in five ways. Name them.
include downcomers, risers, steam-generating tubes, makeup water lines, superheater tubes, and desuperheated tubes.
8. List six types of tubes found in a water-tube boiler.
The upper and lower drum in a water tube boiler have the following differences. The upper drum is known as the steam generating drum. It is half-filled with water, providing a cavity where steam can be generated. Steam enters the upper drum from riser tubes and steam generating tubes that connect it to the lower drum. It is in the lower drum where water becomes heated to the point of boiling. As it does so, the high-pressure steam enters the riser tubes and steam-generating tubes that connect to the upper drum, while drawing in the cooler, lower-pressure water from the upper drum through the downcomer tubes.
9. Contrast the upper and lower drum in a water-tube boiler.
simply detects one of the process variables, and uses that as a basis to adjust a process variable elsewhere. This requires the loop to sense the process variable at the critical, controlled point, which is the job of the sensor. This information is then relayed to a control element via a transmitter. Often, transmitters and sensors are built into the same instrument. A controller then analyzes the data from the sensor, and decides on a course of action, which is sends to a transducer. The transducer translates the controller's commands into a signal that the final control element can understand. Usually, a transducer changes the signal into air pressure for the final control valve, which then modifies the process variable that must be changed in order to generate the desired outcome.
9. How do the basic elements of a control loop work together?
include the firebox, radiant tubes, convection tubes, damper and stack, refractory linining, burners, air registers, fuel systems, instruments, and fans.
9. List the basic components of a furnace.
furnace with an a-frame type exterior structure
A-Frame furnace
complex drawing using equip and line symbols, instruments, control lops and electrical drawings to ID primary and secondary flow paths through the plant. This may provide operating specs, temps, pressures, flows, levels, analytical variables, and mass relationship data (?). these documents may also include pipe sizes, equip specs, motor sizes, etc.
AKA piping and instrumentation drawing. P&ID. It is...
pressure above a perfect vacuum
Absolute pressure (PSIA)
Plot Plan
Another name for an instrument location drawing
Saturation temperature, 212 degrees F
Boiling temp of water
sloping section inside furnace that transitions between the radiant section and convection section; OR the section of refractory that separates fireboxes and burners
Bridgewall
distributed control system
DCS stands for....
Figure 9.7 & 9.11
Figure 9.7 & 9.11
orifice plate, flow nozzle, DP cell
Flow primary element/sensors
the pressure above atmospheric pressure; zero is equipvalent to approximately 14.7 PSI @ sea level
Gauge pressure (PSI) or (PSIg)
???
He likes to look at groupings and types, such as "name 3 types of compressor" etc.
a device that prevents damage to equip and personnel by stopping or preventing the start of certain equip if a preset condition has not been met.
Interlock means?
float, displacer, DP cell
Level primary element/sensors
simple, stand-along, programmable computer that could be used to control a specific process or be networked with others to control a larger operation. Inexpensive, flexible, and provide reliable control and are easy to troubleshoot
PLC (Programmable logic controller)
a special type of interlock that controls a set of conditions that must be satisfied before a piece of equip can be started
Permissive
helix, spiral bellows, bourdon tube, DP cell
Pressure primary element/sensor
a simple sketch that uses symbols to ID instruments and vessels and to describe the primary flow path through a unit
Process flow diagram (PFD)
measures temp by detecting electric resistance in a platinum wire
RTD: resistance temperature detector
???
Review the steps for startup and shutdown
a flow meter that allows fluid to move through a clear tube that has a ball or float in it; numbers on the side of the tube indicate flow rate
Rotameter
these adjust secondary airflow at the burner
air register
a neck-like structre that narrows as it extends between the convection section and stack of a furnace
arch
a corregated metal tube that contracts and expands in response to pressure changes
bellows pressure element
thermostatic steam trap, operates as temp changes
bellows trap
diagram that shows the primary flow path, very simple
block flow diagram
plant demand for steam
boiler load
hook shaped thin walled tube that expands and contracts in response to pressure changes and is attached to a mechanical linkage that moves a pointer.
bordon tube
a rectangular furnace with both a radiant and convection section
box furnace
what is a BTU
british thermal unit. 1 BTU = 1 lb water + 1 degree F
broken tiles placed around burner to protect it from damage
broken burner tiles
above ground furnace that transfers heat primarily through radiant and convection processes. named for its distinct shape.
cabin furnace
process flow
charge
carbon deposits in the tubes of a furnace
coking
an instrumented used to compare a process variable witha set point and initiate a change to return process to set point if variance exist
controller be a what?
upper area of a furnace in which heat transfer is primarily through convection
convection section
tubes above shock bank, transfer heat through convection.
convection tubes
vertical furnace, mainly designed to transfer radiant heat
cylindrical furnace
used to regulate airflow
damper
hot water tubes connecting upper and lower chambers of a water tube boiler
downcomers
negative pressure of air and gas in furnace
draft
preheater in a boiler that uses combustion gases
economizer
solenoid
example of an electric actuated valve
area that contains open flames, area of radiant heat transfer
firebox
direct flame contact
flame impingement
extinguishing burner flame
flameout
intermittent ignition of gas vapors, which then burn back in the burner, can be caused by fuel composition change
flashback
steam trap that uses a float to react to rising condensate
float steam trap
the ratio of output signal from the controller to the error signal
gain
provide access to terminal penetrations or bends on the convection tubes; aka header box doors
header box gaskets
Why is high stack temp bad?
heat in the stack is heat that is being lost.
glowing red spot on the metal or refractory inside a furnace
hot spot
hazy firebox
low burner turnout can result in...
a device used to measure pressure or vacuum
manometer
lower drum of a water tube boiler
mud drum
name some characteristics of a good looking flame
not more than 60% height of box; no impingement; blue color (methane) yellow color (oil)
holes that allow visual inspection of furnace interior
peepblocks with peepholes
air system that typically pushes the air through tubes located in the upper section of the furnace. this air takes full advantage of energy flow passing out of the furnace stack.
preheated air.
combustion devices that transfer convection and radiant heat energy to chemicals or chemical mixtures.
process heaters
primary heat transfer in furnace is in?
radian section
lining of firebox that reflects heat back into the furnace
refractory
tubes with water and steam that connect the drums in a water-tube boiler
risers
receives radiant and convection heat; part of the convection section
shock bank
gas filled sections in a boiler-fuel gas burner
spuds
outlet @ top of furnace through which hot combustion vapors escape from the furnace
stack
drum where steam collects in a water tube boiler, receives steam from steam generating tubes
steam-generating drum
steam that is heated to a higher temp
superheated steam
capillary tubing, thermal and resistance bulb, thermocouple, RTD
temperature primary element/sensor
dissimilar metals generate electric charge
thermocouple
Check, safety, and pressure relief valves
these pieces of equipment are activated by the process, rather than by an actuated controller.
hazy firebox or smoking stack
two symptoms that there isn't enough air getting into the furnace
show exact floor plan for location of equip in relation to the plant's physical boundaries. AKA "Plot plan"
what be a quip locaiton drawing?
process flow is necessary to regulate furnace temperature by providing substance to absorb the heat. Loops, controllers and alarms are frequent to ensure this remains the case.
why is process flow in a furnace critical?
