Power Engineering Part B Unit 6 Exam
Study Guide.
Acidity - answerIn water: the excess of hydrogen ions (H+) over hydroxide ions (OH-) that
occurs where the pH is less than 7
Adsorb - answerTo hold a film of gas or liquid molecules of one material onto the surface of
another material.
Agglome...
Acidity - answer✔In water: the excess of hydrogen ions (H+) over hydroxide ions (OH-) that
occurs where the pH is less than 7
Adsorb - answer✔To hold a film of gas or liquid molecules of one material onto the surface of
another material.
Agglomeration - answer✔The coming together of small, scattered particles, called floc, which
are then able to settle easier and faster particles into larger, heavier out of a liquid.
Alginate - answer✔Plant-sourced compounds that, when added to boiler water, combine with
precipitated scale-forming compounds. This keeps them fluidized and non-adherent.
Alkalinity - answer✔The capacity of water to neutralize bicarbonate, hydroxide, and
occasionally acids. This capacity is caused by the water's content of carbonate, borate, silicate,
and phosphate.
Alum - answer✔A common name for any form of aluminum sulfate. used in water treatment
clarifiers as a flocculant.
Amine - answer✔A broad category of industrial uses. Power plant use ranges from oxygen
scavenging to ammonia-derived organic compound that has various corrosion prevention.
Anion - answer✔An atom with more electrons than protons and, hence, is negatively charged.
Anode - answer✔The positive terminal of an electrolytic cell.
Anodic Inhibitor - answer✔A chemical additive that forms a protective layer of oxide film on the
surface reactions.
Avian Waste - answer✔Biological products deposited by birds, including feathers and feces.
Bicarbonate - answer✔Any salt containing the anion HCO3
Biofilm - answer✔A thin, slimy, adherent film of bacteria.
Biological Fouling - answer✔The result of abundant growth of algae, fungi, and bacteria on
cooling tower surfaces.
Borescope - answer✔A fibre optic instrument used for the visual inspection of narrow passages.
Burette - answer✔An apparatus used to accurately measure the volume of reagent used during
a titration.
Carbonate - answer✔Any salt containing the anion CO32-.
Carryover - answer✔The entrainment of water droplets in the steam leaving the boiler drum.
Cathode - answer✔The negative terminal of an electrolytic cell.
Cathodic Inhibitor - answer✔A chemical additive that provides surface protection by either
slowing the cathodic reaction, or selectively precipitating on cathodic areas, to limit the
diffusion of reducing species to the surface.
Cation - answer✔An atom with less electrons than protons and, hence, is positively charged.
Caustic Cracking - answer✔Intercrystalline cracking of boiler carbon steel caused by a corrosion
reaction in the presence of caustic along the grain boundaries within the metal.
Caustic Embrittlement - answer✔The intercrystalline cracking of steel caused by the presence
of free NAOH stress, boiler water leakage, and concentration of NAOH
Caustic Gouging - answer✔Caustic corrosion that occurs under accumulated scale deposits.
Caustic Soda - answer✔A very high pH (basic) compound, it has various uses in power plants.
Also called sodium hydroxide.
Cellulose - answer✔An insoluble organic substance that is the main constituent of plant cell
walls.
Chelants - answer✔commonly calcium and magnesium. They reduce scale deposits or remove
Chemicals designed to bind to positively charged soluble metal ions, most pre-existing scale.
Clarifier - answer✔A settling tank used to remove sediment from water through sedimentation,
coagulation, or flocculation.
Coagulation - answer✔The use of chemicals that cause suspended matter to join together into
larger particles.
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