527 Q12 Oxy-combustion

The oxidizer in oxy-combustion is

(check all that applies; no partial credit)

• air

• O₂ + air

• O₂ + recirculated CO₂

• O₂ + recirculated H₂O

• H₂O + CO₂

Just like air, the O₂ percentage in the oxidizer of oxy-combustion should be 21% by volume.

• True

• False

Which fuels can be used in oxy-combustion?

(check all that applies; no partial credit)

• Gaseous fuels (CH₄, H₂, etc.)

• Liquid fossil fuels

• Bio-fuels (methanol, glycerol, butanol, etc.)

• Pulverized coal

The exhaust of an oxy-combustion system consists primarily of

• CO₂ + H₂O

• CO₂ + H₂O + O₂ + N₂

• syngas (H₂ + CO)

• CO₂ + N₂

Oxy-combustion facilitates near 100% CC by condensing the exhaust H₂O to get the CO₂

• True

• False

The primary energy penalty in oxy-combustion is associated with

• the operation of the air-separation unit (ASU) to provide the needed inlet O₂.

• the separation of CO₂ from the exhaust.

• the reforming of fuel prior to combustion.

• the fact that oxy-combustion is endothermic.

One of the challenges in oxy-combustion is ensuring complete oxidation of CO to CO₂ to minimize the CO emissions.

• True

• False

The challenges associated with the use of liquid fuels are

(check all that applies; no partial credit)

• the need to properly vaporize the fuel.

• soot formation.

• the need to preheat the reactants.

• SOx emissions (corrosion).

• their low energy density compared to gaseous fuels.

Which of the following statements is true?

• Air-fuel flames are more stable than oxy-fuel flames.

• Oxy-fuel flames are more stable than air-fuel flames.

• Air-fuel and oxy-fuel flames enjoy similar stability.

Which of the following statements is true?

• The pressure of oxy-combustion should always be increased to aid in oxidizing the CO to CO₂.

• The pressure of oxy-combustion should always be decreased to reduce the energy penalty of the air-separation unit (ASU).

• The pressure of oxy-combustion should be optimized to balance CO emissions and ASU energy requirements.

• The performance of oxy-combustion is independent of the system pressure.