Biomass Energy Questions and Answers – Biomass Gasification – 2

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This set of Biomass Energy Multiple Choice Questions & Answers (MCQs) focuses on “Biomass Gasification – 2”.

1. Which of the following is a product of biomass gasification?
a) Hydrogen
b) Steel
c) Carbon (solid)
d) Iron
View Answer

Answer: a
Explanation: Biomass gasification is process that converts biomass into gases in a controlled amount of oxygen or partial combustion. Hydrogen is a product of biomass gasification. Steel, carbon (solid) and iron are not gases.
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2. What is water-gas shift reaction?
a) Carbon dioxide + water → Carbon monoxide + Hydrogen + small heat
b) Carbon monoxide + water → Carbon dioxide + Hydrogen + small heat
c) Carbon dioxide + water + heat → Carbon monoxide + Hydrogen
d) Carbon monoxide + water + heat → Carbon dioxide + Hydrogen
View Answer

Answer: b
Explanation: carbon monoxide + water → carbon dioxide + hydrogen + small heat is the water-gas shift reaction. It is an exothermic reaction as heat is released and not used.

3. Which of the following temperature ranges are suitable for biomass gasification?
a) Above 1000 degree Celsius
b) Between 500 and 600 degree Celsius
c) Between 700 and 1000 degree Celsius
d) Less than 500 degree Celsius
View Answer

Answer: c
Explanation: The most suitable temperature range for biomass gasification is between 700 and 1000 degree Celsius. The reactant is partially oxidized to produce a mixture of gaseous products including hydrocarbons. Sometimes, steam is also used as gasification agents.
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4. What are the three main types of gasifiers?
a) Fixed bed, hydrothermal liquefaction and carbonisation
b) Fixed bed, fluidized gasifiers and carbonisation
c) Carbonisation, liquefaction and entrained flow gasifiers
d) Fixed bed, fluidized gasifiers and entrained flow gasifiers
View Answer

Answer: d
Explanation: Fixed bed, fluidized and entrained flow gasifiers are the three main types of gasifiers used in biomass gasification. Liquefaction and carbonisation are not gasifying techniques.

5. Biomass is moved at a very slow rate in fixed bed gasifier.
a) True
b) False
View Answer

Answer: a
Explanation: Biomass is moved at a very slow rate in the fixed bed gasifier. Hence, it is also called as moving bed reactor and is operated around 1000 degree Celsius.
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6. How is the biomass material and gasification agent fed into an updraft gasifier?
a) Biomass from top, gasifying agent from top
b) Biomass from top, gasifying agent from bottom
c) Biomass from bottom, gasifying agent from top
d) Biomass from bottom, gasifying agent from bottom
View Answer

Answer: b
Explanation: In an updraft gasifier, the biomass material is fed from the top of the reactor and the gasification agent is fed from the bottom of the reactor. As the gasifying agent flows through the biomass, gas is generated and exhausted from the top.

7. What is the contaminant in the product gas that is withdrawn from a low temperature zone in a fixed bed gasifier?
a) Gold
b) Platinum
c) Tar
d) Nickel
View Answer

Answer: c
Explanation: The hot gas coming from the bottom dries the biomass near the top of the vessel and provides heat for pyrolysis of the descending biomass. Along with providing heat, it also embeds tar into it. When the product gas is removed from a low temperature zone, it consists of tar which is a contaminant.
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8. The product gas removed from the low temperature zone undergoes _______ before being used as fuel in combustion for electricity generator.
a) liquefaction
b) condensation
c) evaporation
d) cleaning
View Answer

Answer: d
Explanation: The product gas removed from the low temperature zone undergoes cleaning. This is to remove contaminants like tar from the gas so that it can be used as fuel in combustion engine for electricity generator.

9. How is the biomass material and gasification agent fed into a downdraft gasifier?
a) Biomass from top, gasifying agent from top
b) Biomass from top, gasifying agent from bottom
c) Biomass from bottom, gasifying agent from left side
d) Biomass from top, gasifying agent from right side
View Answer

Answer: a
Explanation: In a downdraft generator, the biomass and the gasifying agent is fed into the vessel from the top. Air or oxygen is then fed into the system homogeneously at the so called throated area.
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10. The tar content of the product gas in downdraft gasifier is _______ updraft gasifier.
a) equal to
b) less than
c) greater than
d) cleaner than
View Answer

Answer: b
Explanation: The tar content of the product gas in a downdraft gasifier is lower than updraft gasifier. However, the particulate content of the gas is higher.

11. Which of the following applications is the product gas from downdraft gasifier suitable for?
a) Fuel for combustion engine
b) Fuel for burning wood
c) Fuel for internal combustion engine
d) Fuel for household purposes
View Answer

Answer: c
Explanation: The product gas from downdraft gasifier is suitable for applications like fuel for internal combustion engine to generate electricity. This is because it consists of less amount of tar and more amount of particulate matter as compared to the product gas from an updraft gasifier.

12. Which of the following applications can the producer gas be used for?
a) Producing nickel
b) Producing copper
c) Producing glucose
d) Producing methanol
View Answer

Answer: d
Explanation: Producer gas can be used to produce methanol in an economically viable manner. Methanol is used as fuel for heat engines as well as feedstock for industries.

13. Which of the following are keys to design a gasifier?
a) Reducing biomass to charcoal and converting charcoal at suitable temperature to produce carbon monoxide and hydrogen
b) Oxidizing biomass to charcoal and converting charcoal at suitable temperature to produce carbon monoxide and hydrogen
c) Reducing biomass to charcoal and converting charcoal at suitable temperature to produce carbon dioxide and hydrogen
d) Oxidizing biomass to charcoal and converting charcoal at suitable temperature to produce carbon dioxide and hydrogen
View Answer

Answer: a
Explanation: The key to gasifier design is to create conditions such that biomass is reduced to charcoal and the charcoal converted to carbon monoxide and hydrogen at suitable temperatures. It is important to note that biomass is reduced and not oxidized.

14. How does air enter and exit in a cross-draft gasifier?
a) Air enters from one of the sides and exits from the top
b) Air enters from one side and exits from the other
c) Air enters from one of the sides and exits from the bottom
d) Air enters from the bottom and exits from the top
View Answer

Answer: b
Explanation: In a cross-draft gasifier, air enters from one of the sides and exits from the other. Cross-draft gasifiers are compactly constructed and require low maintenance.

15. Ash sticks to the side in a cross-draft gasifier.
a) True
b) False
View Answer

Answer: b
Explanation: Ash falls to the bottom in a cross-draft gasifier. The ask does not interrupt the normal operation and hence the gasifier does not need a grate.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter