Petroleum Refining Process
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What is the primary purpose of the scrubber in the continuous coking process?

  • To maintain the reactor temperature and sustain thermal cracking reactions
  • To separate the liquid products from the reactor effluent
  • To produce a clean fuel gas (Flexigas) for boilers and furnaces
  • To condense higher boiling hydrocarbons and recycle them to the reactor (correct)
  • What is the percentage of coke produced in the reactor that is burned to provide heat?

  • 80-90%
  • 50-60%
  • 20-25% (correct)
  • 10-15%
  • What is the main difference between continuous coking and batch-coking technology?

  • The type of feed used in the process
  • The products formed in the process
  • The temperature of the reactor
  • The fact that coke particles are in a continuous system (correct)
  • What is the primary purpose of the reactor in the continuous coking process?

    <p>To thermally crack the feed to a full range of liquid products and coke</p> Signup and view all the answers

    What is the purpose of the heater in the continuous coking process?

    <p>To burn coke to provide the heat necessary for the cracking process</p> Signup and view all the answers

    What is the percentage of coke produced in the reactor that is consumed in the process?

    <p>97%</p> Signup and view all the answers

    What is the purpose of the gasifier in the continuous coking process?

    <p>To produce a clean fuel gas (Flexigas) for boilers and furnaces</p> Signup and view all the answers

    What is the main product of the continuous coking process?

    <p>Lighter products such as naphtha, kerosene, heating oil, and hydrocarbon gases</p> Signup and view all the answers

    What is the primary objective of the hydrocracking process?

    <p>To produce high-quality petroleum products with low sulfur and aromatic compounds</p> Signup and view all the answers

    What is the role of catalytic cracking in the hydrocracking process?

    <p>To scission carbon-carbon single bonds</p> Signup and view all the answers

    What is the relationship between cracking and hydrogenation in the hydrocracking process?

    <p>They are complementary reactions that enhance the overall efficiency of the process</p> Signup and view all the answers

    What is the primary reason for the shift in demand for petroleum products?

    <p>Increased demand for gasoline and jet fuel</p> Signup and view all the answers

    What is the benefit of hydrocracking in terms of by-products?

    <p>Production of by-product hydrogen at low cost and large amounts</p> Signup and view all the answers

    What is the mechanism of hydrocracking?

    <p>The combination of catalytic cracking and hydrogenation</p> Signup and view all the answers

    What is the purpose of the catalyst regenerator in the hydrocracking process?

    <p>To clean and recycle the spent catalyst</p> Signup and view all the answers

    What is the characteristic of all hydrocracking and hydroprocessing processes used today?

    <p>They are fixed bed catalytic processes with liquid downflow</p> Signup and view all the answers

    What is the primary purpose of the refining process in the context of crude oil?

    <p>To separate various fractions of crude oil</p> Signup and view all the answers

    What is the purpose of the desalter in the atmospheric distillation unit (ADU) process?

    <p>To remove impurities from the crude oil</p> Signup and view all the answers

    What is a catalyst?

    <p>A substance that causes reactions between other chemicals</p> Signup and view all the answers

    What is the advantage of using zeolite catalysts over amorphous synthetic silica alumina combinations?

    <p>Higher activity and lower coke yield</p> Signup and view all the answers

    What is the operating pressure of the atmospheric distillation unit (ADU)?

    <p>760 mmHg</p> Signup and view all the answers

    What is the temperature range of the crude oil after it is heated in the furnace in the ADU process?

    <p>399°C to 426°C</p> Signup and view all the answers

    What is the purpose of the regenerator in a Fluidized Catalytic Cracker?

    <p>To regenerate the catalyst</p> Signup and view all the answers

    What is the term used to describe the heaviest fractions of crude oil that leave the bottom of the atmospheric distillation column?

    <p>Residuum</p> Signup and view all the answers

    What is formed during the cracking phenomena in a Fluidized Catalytic Cracker?

    <p>Coke, smaller molecules, and a range of hydrocarbons</p> Signup and view all the answers

    What is the main component of the feedstock in a Fluidized Catalytic Cracker?

    <p>Long-chain hydrocarbons</p> Signup and view all the answers

    What is the purpose of the heat exchangers in the ADU process?

    <p>To heat the crude oil</p> Signup and view all the answers

    What is the purpose of the cyclones in a Fluidized Catalytic Cracker?

    <p>To extract the cracked hydrocarbon vapor</p> Signup and view all the answers

    What is the term used to describe the process of changing the size and/or structure of hydrocarbon molecules?

    <p>Conversion</p> Signup and view all the answers

    What is the term used to describe the groups of hydrocarbon compounds of differing boiling-point ranges?

    <p>Fractions</p> Signup and view all the answers

    What is the primary function of the fractionator in a Fluidized Catalytic Cracker?

    <p>To separate the cracked hydrocarbon vapor into different products</p> Signup and view all the answers

    What is the advantage of using zeolite catalysts in Fluidized Catalytic Cracking?

    <p>Lower coke yield and higher gasoline yield</p> Signup and view all the answers

    What is the approximate yield of polymer gasoline per barrel of olefin feed in the polymerization process?

    <p>0.7 barrels</p> Signup and view all the answers

    What is the primary function of the amine solution in the process?

    <p>To remove hydrogen sulfide and mercaptans from the feed</p> Signup and view all the answers

    What is the typical temperature range for the polymerization reaction?

    <p>300-425°F</p> Signup and view all the answers

    Why is it necessary to remove oxygen from the feed?

    <p>Because oxygen strongly affects the reactions</p> Signup and view all the answers

    What is the purpose of adding a small amount of water to the olefin feed steam?

    <p>To promote ionization of the acid</p> Signup and view all the answers

    What is the typical range of catalyst consumption rates?

    <p>1 lb/100-200 gallons of polymer produced</p> Signup and view all the answers

    What is the purpose of the silica gel or molecular sieve bed in the process?

    <p>To dry the feed</p> Signup and view all the answers

    Why is the polymerization reaction classified as highly exothermic?

    <p>Because it releases a large amount of heat</p> Signup and view all the answers

    Study Notes

    Continuous Coking/Fluid Coking

    • Converts heavy residual crude into lighter products such as naphtha, kerosene, heating oil, and hydrocarbon gases
    • The "fluid" term refers to the fact that coke particles are in a continuous system versus older batch-coking technology
    • Simplified version of Flexicoking

    Process Overview

    • Feed (565°C-plus vacuum resid) enters the scrubber for integrated direct contact heat exchange with reactor overhead effluent vapors
    • Scrubber condenses higher boiling hydrocarbons in the reactor effluent (525°C) and recycles these along with the fresh feed to the reactor
    • Lighter overhead vapors are sent to conventional fractionation and light ends recovery
    • In the reactor, feed is thermally cracked to a full range of liquid products and coke
    • Coke inventory is maintained by transferring bed coke from the reactor to the heater via a transfer line
    • Hot coke from the heater is circulated back to the reactor (through coke transfer line), supplying the heat necessary to maintain reactor temperature and to sustain thermal cracking reactions

    Flexicoking

    • Excess coke is sent to the gasifier where the coke reacts with air and steam to produce a clean fuel gas (Flexigas)
    • Approximately 97% of the coke generated in the reactor is consumed in the process, with a small amount of product coke recovered from the fines system

    Catalysts

    • Acid-treated natural aluminosilicate
    • Amorphous synthetic silica alumina combinations
    • Crystalline zeolites @ molecular sieves
    • Commercial: Zeolite (USY zeolite), with higher activity, higher gasoline yields, and lower coke yield

    Fluidized Catalytic Cracker (FCC)

    • Converts heavy residual crude into lighter products
    • Reactor/Riser, Catalyst, Regenerator, and Fractionator are the main components
    • Cracking phenomena:
      • Formation of coke
      • Formation of smaller molecules
      • Smaller naphtenic+aromatic+olefins formed
      • Cracking of large molecules
      • Producing full range of HC

    Objective

    • To convert heavy oil feedstock into high quality, lighter fuel products (gasoline, naphtha, kerosene, diesel, hydrowax) which can be used as petrochemical plant feedstock or lube basestock

    Reasons

    • Demand for petroleum products has shifted to high ratios of gasoline and jet fuel compared to usage of diesel fuel and home heating oils
    • By-product hydrogen at low cost and large amounts
    • Limiting sulfur & aromatic compound in motor fuels have increased

    Hydrocracking

    • Mechanism of hydrocracking is superimposed of catalytic cracking & hydrogenation
    • Catalytic cracking is the scission of a carbon-carbon single bond
    • Hydrogenation is the addition of hydrogen to a carbon-carbon double bond
    • Cracking & Hydrogenation are complementary processes:
      • Cracking provides olefins for hydrogenation
      • Hydrogenation provides heat for cracking
      • Overall reaction provides excess heat → quenching unit

    Two-Stage Hydrocracker

    • All hydrocracking & hydroprocessing processes are fixed bed catalytic processes with liquid downflow
    • Hydrocracking process may require either one or two stages depending upon the process and the feed stocks used

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    Description

    This quiz covers the steps involved in a petroleum refining process, including heat exchange, condensation, and thermal cracking. It describes the treatment of feed and reactor effluent, and the resulting products.

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