MM317: Energy Materials Quiz
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Questions and Answers

What is the primary benefit of advanced ultra-supercritical combustion systems (AUSC)?

  • They require no maintenance for efficient operation.
  • They operate at high temperature and high pressure. (correct)
  • They operate at low temperature and low pressure.
  • They generate electricity from coal without emissions.

    • What is syn gas primarily composed of?

  • Hydrogen and nitrogen
  • Oxygen and hydrogen
  • Hydrogen and carbon monoxide (correct)
  • Carbon dioxide and methane

    • Which technology aims to achieve near net-zero emissions from power generation?

  • High efficiency turbines
  • Carbon capture and storage (CCS) (correct)
  • Integrated Gasification Combined Cycle (IGCC)
  • Advanced ultra-supercritical combustion systems (AUSC)

    • What does the Integrated Gasification Combined Cycle (IGCC) do with coal?

    <p>Gasifies it to produce a syn gas for electricity generation.</p> Signup and view all the answers

    What is the function of a fuel cell?

    <p>To generate electricity through an electrochemical reaction.</p> Signup and view all the answers

    What material challenges are associated with steam turbines?

    <p>Materials should withstand high temperatures and pressures.</p> Signup and view all the answers

    What role does supercritical water play in AUSC systems?

    <p>It serves as a working fluid in the thermal cycle.</p> Signup and view all the answers

    What is one of the main purposes of carbon capture and storage (CCS) technology?

    <p>To capture CO2 emissions and store it underground.</p> Signup and view all the answers

    What is the primary purpose of cooling and water quenching in syngas coolers?

    <p>To remove particulates and water-soluble impurities</p> Signup and view all the answers

    Why is high-temperature corrosion a significant concern in syngas coolers?

    <p>It increases the operational costs associated with repairs.</p> Signup and view all the answers

    Which material is currently favored for use in syngas coolers due to its corrosion resistance?

    <p>Sanicro 28</p> Signup and view all the answers

    What effect do chlorides have during downtime in syngas coolers?

    <p>They lead to spallation of the oxide scale.</p> Signup and view all the answers

    What is the maximum operating temperature for syngas coolers to mitigate corrosion issues?

    <p>450°C</p> Signup and view all the answers

    Which alloy is mentioned for its susceptibility to corrosion despite being economically viable?

    <p>Alloy 800</p> Signup and view all the answers

    What type of corrosion is primarily exacerbated by the presence of chloride ions?

    <p>Pitting corrosion</p> Signup and view all the answers

    Which characteristic of materials improves resistance to reducing environments in syngas coolers?

    <p>High nickel content</p> Signup and view all the answers

    What is the primary purpose of the absorber unit in an amine scrubber?

    <p>To react CO2 with CO2-lean solvent</p> Signup and view all the answers

    What temperature range is typically used in the stripper unit of an amine scrubber to strip CO2?

    <p>100–140°C</p> Signup and view all the answers

    Which of the following is a common issue associated with amine scrubbing?

    <p>Corrosion resistance in scrubber environments</p> Signup and view all the answers

    Which technology is commonly used for pre-combustion carbon capture?

    <p>Integrated Gasification Combined Cycle (IGCC)</p> Signup and view all the answers

    What is produced when CO reacts with steam in a catalytic shift reactor?

    <p>Hydrogen and CO2</p> Signup and view all the answers

    What is a potential alternative to amine scrubbing for post-combustion CO2 separation?

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

    What can contribute to pitting or localized corrosion in amine scrubbers?

    <p>Degradation products of amines</p> Signup and view all the answers

    What is the purpose of the gasifier process?

    <p>To produce a gaseous mix known as synthetic gas from solid or liquid fuels</p> Signup and view all the answers

    In high-pressure gasifiers, which process is most suitable for CO2 capture?

    <p>Oxygen-blown gasification</p> Signup and view all the answers

    What is a major operating condition for a gasifier chamber in terms of temperature and pressure?

    <p>1250-1550°C and 3 MPa or higher</p> Signup and view all the answers

    Which refractory material is preferred for high wear areas within a gasifier?

    <p>Chromium oxide with &gt;85 wt% Cr2O3</p> Signup and view all the answers

    What type of cooling method do water-cooled gasifiers primarily employ?

    <p>Water with Al2O3-SiC refractory linings</p> Signup and view all the answers

    What is a major drawback of high chromium oxide refractory materials?

    <p>Low availability and high cost, plus health risks associated with Cr⁶⁺</p> Signup and view all the answers

    What form can slag in a gasifier take?

    <p>Both liquid slag that flows out and solid slag that solidifies</p> Signup and view all the answers

    Which material has poor thermal shock resistance but good chemical resistance?

    <p>Fuse-cast materials</p> Signup and view all the answers

    What is the expected lifespan of air-cooled gasifiers using high chromium oxide materials?

    <p>3 months to 2 years</p> Signup and view all the answers

    What is a significant benefit of CO2 being concentrated in the shifted fuel gas?

    <p>It allows for lower CO2 capture costs.</p> Signup and view all the answers

    Which CO2 separation method is noted for having a high efficiency penalty?

    <p>Rectisol process</p> Signup and view all the answers

    What is a key challenge associated with oxyfuel combustion?

    <p>It requires an expensive air separation unit.</p> Signup and view all the answers

    Which contaminant is NOT typically found in captured CO2?

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

    Which approach is considered the cleanest option for flue gas recycling?

    <p>Recycle flue gas after desulfurization.</p> Signup and view all the answers

    What is a major concern under advanced supercritical plant conditions?

    <p>Corrosion of materials in water-wall tubes.</p> Signup and view all the answers

    Which method selectively allows CO2 to pass while blocking other gases?

    <p>Advanced separation membranes</p> Signup and view all the answers

    What may increase the size of the flue gas desulfurization (FGD) plant?

    <p>Recycling flue gas with minimal pre-cleaning.</p> Signup and view all the answers

    Study Notes

    Steam Turbine and Gas Turbine

    • Components of steam turbines are critical for energy conversion and efficiency.
    • Gas turbines convert gas to mechanical energy and require durability against extreme conditions.

    Material Design Requirements

    • Materials must withstand high temperatures, thermal shock, erosion from particulates, and corrosive gases.
    • Challenges include current material limitations in performance and longevity under extreme operating conditions.

    Advanced Power Generation Systems

    • Advanced Ultra-Supercritical Combustion (AUSC) operates above critical thresholds of temperature and pressure, utilizing water as a supercritical fluid.
    • Integrated Gasification Combined Cycle (IGCC) converts coal into syngas (hydrogen and carbon monoxide) through gasification.

    High-Temperature Material Use

    • Gasifier chambers operate between 1250 and 1550°C and at pressures of 3 MPa or higher.
    • Refractory materials protect against erosion, corrosion, and thermal stress in gasifiers.

    Types of Refractory Materials

    • Fuse-cast materials offer chemical resistance but poor thermal shock resistance.
    • High chromium oxide refractories are preferred in severe wear areas due to their enhanced chemical resistance but pose toxicity risks.

    Cooling Systems in Gasifiers

    • Gasifiers can be cooled using water or air; water-cooled systems have longer service lives due to slag freezing.
    • Air-cooled systems utilizing high chromium oxide have shorter lifespans due to intense cooling needs.

    Syngas Cooling and Cleaning Requirements

    • After syngas generation, cooling and cleaning are necessary to remove impurities such as ammonia and hydrogen sulfide.
    • High temperatures in syngas coolers can accelerate sulfur-induced corrosion, requiring material resilience to corrosive environments.

    Material Selection for Syngas Coolers

    • Carbon and low-alloy steels face high corrosion rates; stainless steel 310 offers reduced corrosion but has water-side issues.
    • Sanicro 28 stainless steel is favored for high resistance to multiple corrosive agents and environments.

    CO2 Capture and Storage Techniques

    • Post-combustion CO2 capture often utilizes low-temperature liquid scrubbing with amine solvents.
    • Key components include absorbers for CO2 reaction and strippers for separating CO2 from the solvent.

    Corrosion Challenges in CO2 Scrubbing

    • Corrosion resistance in amine scrubbers is crucial; performance of corrosion inhibitors and surface coatings is essential for longevity.
    • Knowledge gaps in corrosion mechanisms remain a significant challenge in material selection.

    Pre-Combustion Carbon Capture

    • Achieved through the gasification process in IGCC plants, removing CO2 from syngas prior to combustion.
    • High concentration CO2 separation approaches advance cost-effective capture methods.

    Oxy-Combustion CO2 Capture

    • Oxyfuel combustion uses an oxygen-rich environment, producing a CO2-rich waste stream for easier capture.
    • Major challenges include the need for high-cost air separation units and increased SOx emissions.

    CO2 Transport and Storage Challenges

    • Impurities in captured CO2, such as SOx, HCl, and NOx, complicate effective transport and storage.
    • Strategies for purification and effective storage are crucial to mitigate environmental impact.

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    Related Documents

    MM317: Energy Materials Lecture Notes PDF

    Description

    Test your knowledge on steam and gas turbines and their components in this MM317 Energy Materials quiz. Explore material design requirements and challenges faced in current materials used for energy applications. Perfect for students in metallurgical and materials engineering.

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