OXY COAL COMBUSTION MUNAWAR HUSSAIN ROLL.NO. 05 M.PHIL COAL TECHNOLOGY
Overview of oxy-coal combustion technology. Introduction to oxy-coal combustion. Oxy-coal combustion principles. The challenge of reducing CO2. Technology options for carbon capture. Advanced coal‐fuelled electricity generation technologies. History of oxy-fuel combustion application. Oxy- Coal plants system major component. Oxy‐Coal combustion advantages. Oxy‐Coal combustion challenges. Pressurized oxy‐Coal combustion. Current and future oxygen (O2) supply technologies for oxy-
Coal combustion.
Oxy-coal combustion
In most conventional combustion processes, air is used as the source of oxygen.
Nitrogen is not necessary for combustion and causes problems by reacting with oxygen at combustion temperature.
With the current push for CO2 sequestration to ease global warming, it is imperative to develop cost-effective processes that enable CO2 capture.
The use of pure oxygen in the combustion process instead of air eliminates the presence of nitrogen in the flue gas, but combustion with pure oxygen results in very high temperatures.
Overview of oxy-coal combustion technology
Industrial furnaces have been using oxy-fuel combustion technology for many years in the glass, aluminum, cement, steel, and incineration sectors.
A high concentration of nitrogen in the flue gas can make CO2 capture unattractive.
Recycling of hot flue gas has also been suggested to reduce furnace size and NOx emissions for metal heating furnaces.
Lately, interest has been paid to oxy-coal combustion as a means to reduce pollutant emission control cost and create a CO2 gas stream that can easily be compressed and sequestered.
Overview of oxy-coal combustion technology
Oxy-coal combustion is the process of burning a coal using pure oxygen instead of air as the primary oxidant.
Oxy-fuel combustion is currently considered to be one of the major technologies for carbon dioxide (CO2) capture.
The attraction of coal as a fuel source is due to several factors. First, it is abundant and most cost affordable energy resources
Coal plays a very important role in our day-to-day lives. Currently, about 40% of the world’s electricity is
generated with coal. In 1982 oxy-fuel combustion was proposed to produce
CO2 for Enhanced Oil Recovery.
Introduction to oxy-coal combustion
3
CO2 Capture
And Sequestrati
on
COAL
PARTIAL COMBUSTION
Fuel Cell
PETROCHEMICAL O2
water shift
CO2 Scrubbing
IGCC
Air
AIR BLOWN IGCC
IGCC
H2 H2 GT
CO22
CFB USC CFB
O2 Oxygen Fired CFB or PC
PC USC PC
COMPLETE COMBUSTION
AirPost-
combustion capture
CO22
ConcentratedCO2
Carbonate looping
CO22
Near-zero emissions Carbon Free Power
CHEMICALLOOPING
Introduction to oxy-fuel combustion
Oxy-coal combustion principles
Scenario Description
6°C Scenario (6DS)
Assumes no new policies are added to those currently in place. In the absence of efforts to stabilize atmospheric concentrations of GHGs, average global temperature rise is projected to be at least 6°C in the long term.
4°C Scenario (4DS)
4°C Scenario (4DS) Assumes recent government policy commitments are to be implemented in a cautious manner – even if they are not yet backed up by firm measures. In many respects, this is already an ambitious scenario that requires significant changes in policy and technologies. Moreover, capping the temperature increase at 4°C requires significant additional cuts in emissions in the period after 2050.
2°C Scenario (2DS)
Sets out an illustrative energy pathway for meeting the goal of limiting the increase in average global temperature to 2°C by 2050 a temperature rise deemed to be relatively low-risk.
The challenge of reducing CO2
The challenge of reducing CO2
These are scenarios and not projections. The IEA states that the 2DS will be impossible to achieve without significant decoupling of energy use from economic activity.
The IEA predicts a rise of CO2 emissions originating from energy production from 31 Gtonnes to 58 Gtonnes by the year 2050
In the 6DS (see Figure 2), which, according to computer models, would cause the average global temperature to rise 6°C), substantially above the low‐risk 2DS scenario of 2°C.
To reduce these potential risks, ways must be found to reduce the world’s carbon intensity while still promoting productivity and maintaining the benefits of affordable electricity.
The challenge of reducing CO2
Technology options for carbon capture
Commercially or near‐commercially available coal power systems
Pulverized coal and fluidized bed combustion. Integrated gasification combined cycles. Oxy‐combustion.
Future technologies
Advanced fuel cells. Chemical looping combustion. Closed Brayton power cycles. Pressurized oxy‐combustion.
Advanced coal‐fuelled electricity generation technologies
1940-1950 High
Temperature application welding ,me
tal cutting ,flame polishing
1950-1960 Productivity enhancement via O2
enrich combustion
glass, aluminum,
cement industries
1980-1990 idea of
using oxy –coal
combustion with RFG
for enhance oil recovery
(1982)
1990-2000 Nox reduction
glass melting
furnaces OEC coal
fired boilers
2000-2010
CO2 Reduction
power generation
industry IGCC and oxy fuel
boiler application
History of oxy-fuel combustion application
History of oxy-fuel combustion application
Air Separation Unit (ASU) Technology that removes nitrogen and other species from air cryogenically to
produce a high‐quality stream of oxygen. Oxy Boiler large system that combusts coal with oxygen separated from air. The oxy‐
fired boiler is in many ways similar to a traditional air‐fired one, consisting of similar technology. The primary difference is the oxidant: in the case of an oxy boiler, air is simulated by diluting nearly pure oxygen with recycled flue gas (RFG) to attempt to achieve a similar excess oxygen level in the exiting flue gas of ~3–5% and keep temperatures under control.
Gas Quality Control System (GQCS) Contains the environmental controls, which are typically far less extensive than
in PC systems. CO2 Purification Unit (CPU) At a minimum, the CPU will include a flue gas drying sub‐system and
compressors to deliver the product CO2 to a receiving pipeline or geological storage site. If required, it will also include a partial condensation process to clean the product CO2 and remove impurities to specified levels.
Oxy-coal combustion plants system major component
Oxy-coal combustion plants system major component
The mass and volume of the flue gas are reduced up to 75%. With reduction in flue gas volume, less heat is lost in the flue
gas. The size of the flue gas treatment equipment can be reduced
by 75%. The flue gas is primarily CO2, suitable for sequestration. The concentration of pollutants in the flue gas is higher,
making separation easier. Most of the flue gases are condensable; this makes
compression separation possible. Heat of condensation can be captured and reused rather than
lost in the flue gas. Because nitrogen from air is not allowed in, nitrogen oxide
production is greatly reduced.
Oxy‐combustion advantages
Oxy‐combustion needs an integrated plant and oxy‐combustion development requiring the commitment of the entire power plant to the technology.
Thus, the technology development path for oxy‐combustion may be more costly than for pre‐combustion or PCC, which can be developed on slip‐streams of existing plants.
Auxiliary power associated with air compression in a cryogenic ASU will reduce net plant output by up to 15% compared to an air‐fired power plant with the same capacity.
Plot space requirements are significant for the ASU and CPU and overall should be comparable to PCC.
Air‐fired combustion is commonly anticipated for start‐up of oxy‐combustion power plants. The very low emissions achieved by oxy‐combustion with CO2 purification cannot be achieved during air‐fired start‐up without specific flue gas quality.
Oxy‐coal combustion challenges
Conducting oxy‐combustion under gas pressure (typically at ~10–15 bar [160–230 psig]) has been proposed to improve net efficiency and potentially reduce plant costs.
The major efficiency benefit from pressurized oxy‐combustion is the reduction of latent heat losses in the flue gas.
There are a number of developers proposing pressurized oxy‐combustion operations at pilot scale but none of these have been deployed yet.
There is relevant pressurized air‐coal combustion experience up to 250 MWth, which might be applicable to pressurized oxy combustion.
A parallel challenge to pressurized oxy‐combustion is the development of the associated gas pressurized boiler design.
Capital costs for pressurized oxy‐combustion power plants with uncertainty comparable to atmospheric pressure oxy‐combustion power plants.
Pressurized oxy‐ coal combustion
Pressurized oxy‐ coal combustion
Existing Pilot Scale (<5MWt)EER(CA), 3.2MW; IFRF(Netherland), 2.5MW; IHI(Japan); Air Liquide,B&W(OH), 1.5MW; CANMET(Canada), 0.3MW; Alstom(CT),3.0MWCFB, IVD(Germany) 0.5MW;
Planned Pilot Demonstration (>20MWt)Vattenfall 30MWt Schwartz Pump Germany,
Japan(IHI)-Australia (Queensland) Oxy-fired retrofit with Oxygen plant, PF boiler (Callide A 30MWe Unit owned by CS Energy) Hamilton (OH) B&W 24 MWe retro fit.
Current and future oxygen (O2) supply technologies for oxy-coal combustion
Industrial Park Schwarze Pumpe(Germany)
Current and future oxygen (O2) supply technologies for oxy-coal combustion
Doosan Babcock has modified its Clean Combustion Test Facility (CCTF) in Renfrew, Glasgow, Scotland, to create the largest oxy-fuel test facility currently in the world.Oxy-Fuel firing on pulverized coal with recycled flue gas demonstrates the operation of a full-scale 40 MW burner for use in coal-fired boilers.
Current and future oxygen (O2) supply technologies for oxy-coal combustion
Current and future oxygen (O2) supply technologies for oxy-coal combustion
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