Biomass Energy Objective Questions on “Biomass Conversion Technologies – 2″.
1. What are the two main products of anaerobic digestion?
a) Biogas and bio-fertilizer
b) Waste water
c) Producer gas
d) Syngas
Answer: a
Clarification: The two main products of anaerobic digestion are biogas and bio-fertilizer. Wastewater is the input to the anaerobic digester. Producer gas is produced during pyrolysis.
2. Which of the following organic compounds are present in biogas?
a) Butane gas and carbon dioxide
b) Methane gas and carbon dioxide
c) Nitrogen
d) Sodium
Answer: b
Clarification: Methane gas and carbon dioxide are present in biogas. Butane is not present in biogas. Nitrogen and sodium are not organic compounds.
3. Which of the following are considered as contaminant gases in biogas?
a) Chlorine
b) Fluorine
c) Nitrogen, hydrogen and carbon monoxide
d) Methane gas and carbon dioxide
Answer: c
Clarification: Nitrogen, hydrogen and carbon monoxide are the contaminant gases present in biogas. Methane gas and carbon dioxide constitute the fuel present in biogas. Chlorine and fluorine are not present in biogas.
4. Which of the following products of anaerobic digestion consists of organic humus and nutrients?
a) Biogas
b) Chlorine
c) Top soil
d) Bio-fertilizer
Answer: d
Clarification: Bio-fertilizer is a product of anaerobic digestion consisting of organic humus and nutrients for plantation. Top soil and chlorine are not products of anaerobic digestion. Biogas does not consist of organic humus.
5. Which of the following are used to store manure?
a) Silos and cellars
b) Plastic bottles
c) Glass bottles
d) Tin cans
Answer: a
Clarification: Silos and cellars are used to store manure. Manure bags are specifically designed to store manure. Plastic bottles, glass bottles and tin cans are not used to store manure.
6. What are the three methods of pre-treatment of influent for anaerobic digestion?
a) Galvanization, pyrolysis and pre-heating
b) Mechanical treatment, pre-heating and thermal treatment
c) Galvanization, pyrolysis and thermal treatment
d) Pyrolysis, thermal treatment and pre-heating
Answer: b
Clarification: Mechanical treatment, pre-heating and thermal treatment are the three different pre-treatment techniques of anaerobic digestion. Galvanization is a process to prevent corrosion of metals. Pyrolysis is a thermo-chemical process and not a bio-chemical process.
7. Thermo-chemical processes have higher efficiencies than bio-chemical processes.
a) True
b) False
Answer: a
Clarification: Thermo-chemical processes do have higher efficiencies than bio-chemical processes. In fact, they also have quicker reaction times and superior ability to decompose most organic compounds.
8. Which of the following is best suited to decompose lignin?
a) Anerobic digestion
b) Fermentation
c) Thermo-chemical conversion techniques
d) Bio-chemical conversion techniques
Answer: c
Clarification: Thermo-chemical conversion techniques can decompose lignin. When compared with bio-chemical conversion techniques, they have superior ability to decompose most organic compounds. Anaerobic digestion and fermentation are bio-chemical processes.
9. Which of the following are types of pyrolysis?
a) Flash and ablative
b) Intermediate and anaerobic digestion
c) Anaerobic digestion and fermentation
d) Fermentation and intermediate
Answer: a
Clarification: Flash and ablative are types of pyrolysis. Anaerobic digestion and fermentation are bio-chemical processes and are not types of pyrolysis.
10. Bio-oil has double the heating value of conventional fuel oil.
a) True
b) False
Answer: b
Clarification: Bio-oil has half the heating value of conventional fuel oil. It is produced after condensing the hot vapors in fast pyrolysis.
11. What are the three types of hydrothermal processing of biomass?
a) Hydrothermal liquefaction, hydrothermal gasification and ablate pyrolysis
b) Hydrothermal liquefaction, hydrothermal gasification and fast pyrolysis
c) Hydrothermal liquefaction, hydrothermal gasification and hydrothermal carbonisation
d) Intermediate pyrolysis, hydrothermal gasification and ablate pyrolysis
Answer: c
Clarification: Hydrothermal liquefaction, hydrothermal gasification and hydrothermal carbonisation are the three types of hydrothermal processes. Intermediate, fast and ablate are the types of pyrolysis.
12. Which of the following is the mildest hydrothermal process?
a) Hydrothermal gasification
b) Hydrothermal liquefaction
c) Ablate
d) Hydrothermal carbonisation
Answer: d
Clarification: Hydrothermal carbonisation is the mildest of the three hydrothermal processes. Ablate is not a hydrothermal process. It is a type of pyrolysis.
13. Which of the following hydrothermal processes produces syngas?
a) Hydrothermal gasification
b) Hydrothermal liquefaction
c) Fermentation
d) Hydrothermal carbonisation
Answer: a
Clarification: Hydrothermal gasification or supercritical water gasification (SCWG) occurs temperatures greater than 375 degree Celsius and pressure above 200 bar. It produces syngas. Fermentation is not a type of hydrothermal process. It is a bio-chemical process.
14. Hydrothermal liquefaction produces _________
a) syngas
b) bio-crude
c) bio-oil
d) producer gas
Answer: c
Clarification: Hydrothermal liquefaction produces bio-crude which can be distillated to obtain petroleum products. Bio-oil is produced in fast pyrolysis. Producer gas is produced in pyrolysis and syngas is produced in hydrothermal gasification.
15. Which of the following produces a solid hydro-char?
a) Catalytic liquefaction
b) Carbonisation
c) Hydrothermal gasification
d) Hydrothermal carbonisation
Answer: d
Clarification: Hydrothermal carbonisation occurs at temperatures between 180 and 250 degree Celsius and pressures between 20 and 40 bar. It produces a solid hydro-char with properties similar to a low rank coal.