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