30 Questions
What is the primary purpose of the water-gas shift reaction in oxy-fuel technologies?
To convert CO to CO2 and H2
Which process is common to Integrated Gasification Combined Cycle (IGCC) power plants?
Water-gas shift
What is the main feedstock for oxy-fuel technologies?
Coal
In the steam reforming process, what is the chemical equation for the conversion of CH4 to CO and H2?
$CH4 + H2O \rightarrow CO + 3H2$
What is the method used for the separation of H2 from the H2/CO2 mixture after the water-gas shift reaction?
Membrane separations
What is the primary product of the water-gas shift reaction?
CO2
What is the purpose of the air separation unit in an Integrated Gasification Combined Cycle (IGCC) power plant?
To produce O2 for combustion
What is the primary purpose of carbon capture in power generation?
To reduce CO2 emissions
What is the main purpose of the steam reforming process in natural gas recovery?
To convert CH4 to CO and H2
What is the end goal of the carbon capture process in the context of power generation?
Transport to long term storage
What is the overall stoichiometry after the water-gas shift reaction when pure carbon is the component gasified?
C(s) + 2H2O → CO2 + 2H2
What is the composition of CO2 in the situation where pure carbon is gasified?
33%
What is the current capital cost difference between gasification of coal and conventional coal-fired generation?
30%
How many large scale plants worldwide are currently using gasification of coal?
4
What is the maximum efficiency of fuel cells when employing Hydrogen from IGCC?
83%
What are the advantages of gasification?
Higher Carnot efficiencies and production of low molecular weight synthetic fuels
What does the capture cost comparison indicate between absorption capture in post-combustion capture and precombustion capture involving IGCC?
Essentially the same
What primarily involves H2 recovery in carbon capture?
Liquid phase CO2 absorption
What additional power demand arises in the reformer operation?
High temperature
What is the equation for the minimum power in the given context?
See equation $Minimum Power = FT \Delta G = (28.2 + 15.3) = 43.5 GW$
What are the advantages of fluidized bed gasification units compared to fixed or slow moving bed units?
Rapid heat transfer, temperature control, and higher throughput
What is the minimum gas velocity for fluidization obtained from?
Ergun equation
What is the typical range for gasification temperature to ensure thermodynamic equilibrium and fast kinetics?
1200-1400K
What are the two types of solid gasification units mentioned in the text?
Co-current moving bed and counter-current moving bed
What are the common disadvantages of fluidized bed gasification units mentioned in the text?
Low conversion efficiency and influence by back-mixing process
What determines the average conversion of the carbon-based feedstock in designing a solid phase gasification unit?
Residence time distribution (RTD)
What are the new designs being developed to overcome traditional fluidized bed design drawbacks?
Entrained Flow Gasifiers and Transport Gasifiers
What describes the behavior of reacting particles in the gasification process?
Partially reacted particle and flaking ash or gaseous products causing shrinkage
What type of gasification units are suitable for gasification of low-grade and higher grade solid fuels, as well as fuels forming highly corrosive ash?
Fluidized bed units
What is the fluidization velocity?
The velocity at which particles in the packed bed become 'fluidized'
Study Notes
Types of Solid Gasification Units
- Two types of solid gasification units are co-current moving bed and counter-current moving bed.
- Co-current moving bed units operate at low throughput and produce high-temperature gas with low tar levels.
- Counter-current moving bed units have low throughput, moderate temperature gas output, and high tar levels.
- Fluidized bed gasification units have advantages such as rapid heat transfer, temperature control, and higher throughput than fixed or slow moving beds.
- Fluidized bed units are suitable for gasification of low-grade and higher grade solid fuels, as well as fuels forming highly corrosive ash.
- Common disadvantages of fluidized bed gasification units include low conversion efficiency and influence by back-mixing process.
- New designs like Entrained Flow Gasifiers and Transport Gasifiers are being developed to overcome traditional fluidized bed design drawbacks.
- Fluidization velocity is the velocity at which particles in the packed bed become "fluidized."
- The minimum gas velocity for fluidization is obtained from the Ergun equation.
- Two models describe the behavior of reacting particles: partially reacted particle and flaking ash or gaseous products causing shrinkage.
- The gasification temperature is typically maintained in the range of 1200-1400K to ensure thermodynamic equilibrium and fast kinetics.
- Designing a solid phase gasification unit requires considering the average conversion of the carbon-based feedstock, largely determined by residence time distribution (RTD).
Test your knowledge of solid gasification units with this quiz! Learn about co-current and counter-current moving bed units, fluidized bed gasification, new designs like Entrained Flow Gasifiers and Transport Gasifiers, gasification temperature, and more.
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