PM Controls in Refineries

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PM Controls in Refineries

• For IIASA workshop
• by Henk Schipper
• Technical Coordinator - CONCAWE

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Sources of particulates in refineries

• Oil fired equipment
• process heaters
• boilers (burning oil)
• Fluids Catalytic Cracking Unit (FCCU)
• catalyst regenerators of such units

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PM from Oil fired Equipment

• Types of PM in flue gases
• soot, the particle size is below 1 µm visible
  smoke from a stack is caused by all particles but
  mainly 0.5 to 5 µm
• cenospheres  they originate from the liquid
  phase residues of combustion of heavy oil
  droplets, at relatively low temperature (lt 700
  C), the size is equal to or larger than that of
  the original oil droplets
• coke particles, formed through liquid phase
  cracking in combustion at high temperatures (gt
  700 C). The particle size is generally from 1 to
  10 µm.
• fine particles (lt 0,01 µm) their contribution to
  the total mass emission is negligible.

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Catalyst Regeneration

• Coke deposited on catalyst is passed through a
  regenerator, where it is burned off. The
  combustion gasses are passed through cyclones
  before disposal to the stack. About 90 is lt 10
  mm. The main control for PM emissions is correct
  operating conditions! Basic design includes 2
  stage cyclones
• Further improvements by (very site specific)
• tertiary cyclones
• multi cyclones
• electrostatic precipitators
• wet flue gas scrubbers

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Coking Plants

• Coking as described here is a severe thermal
  cracking process that maximises the severity to
  the extent that coke is formed while production
  of the more profitable light products is
  maximised
• Unburnt gases from the calciner are burned in an
  incinerator, then passed through a waste heat
  boiler before being released to the atmosphere
  via a dust collection system
• PM emissions from
• furnace flue gas
• coke fines (particulates) from handling of coke
• the calciner.
• Controls same as for Cat Cracker. In addition bag
  filters can be used for handling of coke fines at
  a Capex of about 5 M EUR.

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Process Fired Heaters
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BOILERS
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Cat Cracker Coker