AIR POLLUTION CONTROL ABATEMENT FOR THERMAL ......AIR POLLUTION CONTROL ABATEMENT FOR THERMAL (COAL...
Transcript of AIR POLLUTION CONTROL ABATEMENT FOR THERMAL ......AIR POLLUTION CONTROL ABATEMENT FOR THERMAL (COAL...
AIR POLLUTION CONTROL ABATEMENT
FOR THERMAL (COAL PLANTS)
Leon van Wyk
Project Development Specialist, Lesedi, South Africa
• What is MES and why?
• Technologies available to comply with MES
• Design approaches required to meet compliance
• Closing remarks
PRESENTATION OUTLINE
• Lesedi evolved from Intens Engineering which was
founded in 1984 servicing Koeberg Nuclear Power
Station. We have since diversified into a major multi-
disciplinary engineering, procurement and construction
(EPC) company.
• We are projects orientated and technology agnostic
• Partnering for cost effective solutions whilst combining
owners engineering with design engineering to provide
effective solutions within a South African context
OVERVIEW OF LESEDI
• MES – Minimum Emission Standards evolved from scientific studies world
wide to understand the human and animal health considerations.
• Reportable emission gasses (criteria pollutants) all have a negative effect to
predominantly the respiratory system in humans and contributes to mortality
rates in affected regions.
• South Africa has two priority areas as classified by the Department of
Environmental Affairs – Highveld and Waterberg
• Mpumalanga is worlds worst affected NOX contaminated area according to
a recent study (Greenpeace)
• Pollutants and greenhouse gases are different and need to be managed
differently
WHAT IS MES AND WHY?
SOUTH AFRICAN PRIORITY AREAS
6
PM10: NOx:
SO2:
Graphs for the Highveld Priority Area
GREENHOUSE VS POLLUTANTS
• Greenhouse gasses affects global
warming
– CO2 biggest contributor
• Pollutants affects human health
– Major criteria pollutants (to be measured by
countries)• Particulate Matter, SO2, NOX, Mercury – not yet
legislated in South Africa
• Both pollutants and greenhouse gasses
come from fossil fuel combustion in power
generation activities
• Pollutants are managed through
abatement technology, greenhouse gas
technology in infancy – currently planned
to apply tax in South Africa from June
2019 – energy efficiency
• Particulate Matter
– Microscopic solids inhaled and stays in lungs; PM2.5 of greatest concern as this can reach
blood streams
• NOX
– Nitrogen oxides contain a group of pollutants, NO2 the greatest concern for human health
– Aggravates respiratory diseases – asthma; Addition with water vapor can cause acid rain –
nitric acid
• SOX
– Difficulty breathing; Gaseous SO2 harms trees and plants by decreasing growth potential
– Acid rain occurring with water vapour
• Mercury
– Kidney and central nervous systems gets affected most; Usually through food chain – e.g.
fish
POLLUTANTS – WHY WE CARE
South African limits International Trends
Particulate Matter 50mg/Nm3 <10mg/Nm3
Sulphur Dioxide 500mg/Nm3 <200mg/Nm3
Oxides of Nitrogen 750mg/Nm3 <150mg/Nm3
NB: This was taken in South African winter
TROPOSPHERIC MONITORING
National Environmental Management:Air Quality Act
(No 39 of 2004)
Priority AreaAir Quality
Management Plan
Ambient Air Quality Standards
Dust Fallout Management Regulations
MinimumEmissionStandards
Municipal By-laws
EmissionLicence
AIR QUALITY LEGISLATION IN SOUTH AFRICA
PRODUCTS OF COMBUSTION
• C + O2 = COX (CO2 and CO)
• S + O2 = SOX (SO2)
• N + O2 = NOX (N2O and NO2)
• Particulates
• Particulate Emissions– Fabric Filter Plants
– Electrostatic Precipitators
• SOX
– Wet Flue Gas Desulphurization applications
– Semi dry and dry applications to reduce water
• NOX
– Pre and post combustions applications
• Mercury– Form of which the mercury occurs important – oxidation required through
additional injection systems
• Multi-pollutant plants– Best suited technology is a circulating dry scrubber with FFP to reduce PM,
SOX and Mercury.
TECHNOLOGIES AVAILABLE
• Fabric Filter Plants
TECHNOLOGIES AVAILABLE
Pulse Jet
• The gas flows fromoutside the bags to theinside
• The bags are supported tothe tube plate at the topend
• Anti collapse cages
• Primary pulse andsecondary flow create ashock wave
• in-line or off-line cleaning
TECHNOLOGIES AVAILABLE
---------
----
----------
--
---
-
-
-
+’ve
---------
----
--------- -
--
---
-
-
-
+’ve
dirty gas in
cleaned gas out
collecting plates
migration velocity
discharge electrode (-’ve)
corona field
• Electrostatic Precipitators
Improvements:Flue Gas Conditioning with NH3 and SO3
Higher Frequency Power SuppliesControl System UpgradesSystem Refurbishments
• SOX
– Pre-combustion limited to coal beneficiation and fuel switching
– During combustion sorbent injection (also CFB)
– Post combustion most favorable for legislated limits
– Is there a dry WGD for conventional coal?
TECHNOLOGIES AVAILABLE
Wet FGD• Fully saturates the flue gas with water.• Limestone or lime reagent.• Can produce commercial-grade gypsum
byproduct.• Higher capital cost / lower operating costs.• High relative water consumption• Water saving due to cooling possible
Semi-dry FGD• 20°C approach to saturation
temperature.• Lime reagent – product of limestone.• Disposal byproduct.• Lower capital cost / higher operating
costs. • Low relative water consumption
• NOX
– Thermal NOX vs Fuel NOX
– Pre-combustion limited to fuel switching
– During combustion characteristic of
• Combustion process (wall fired vs corner fired) and/or
• Firing systems– Conventional
– Staged combustion burners
– Post combustion SCR and SNCR
• Split NOX into diatomic nitrogen and water
• Temperature important
TECHNOLOGIES AVAILABLE
• Multipollutant– CFB FGD – Graf Wulff / Lurgi Process (Numerous suppliers) vs Wetted Solids
Absorbers (GE and Hitachi)
TECHNOLOGIES AVAILABLE
• Each technology has an effect on the overall power plant
• The use of modelling techniques and advance analysis
paramount to the correct technology application required
– with validation
• A stepwise approach is suggested to have a cost
effective solution achieved – specifically for PM in South
Africa
• Make owner part of solution finding – Understanding the
problem usually more complex than solutions.
INTEGRATED DESIGN
• Should it be gone with coal?
– South Africa is an island – energy management not fully
comparable to other countries
– Getting the mix right – IRP transparency
– Grid stability king – how do we manage emissions in an
changing environment – relative emissions vs point source
– Flexibility in grid – clean the emissions, make coal work better
CLOSING REMARKS
CLOSING REMARKSGERMANY DURING TYPICAL WINTER DAY – JANUARY 2019
CLOSING REMARKSGERMANY DURING TYPICAL SUMMER DAY – JUNE 2018
• Not easy or cost attractive road – However
environmental compliance does generate income
• The sooner the better – pressures on plants become
more relevant for production.
• Design for future requirements should be included
• Understanding technology for South Africa – using
international design know-how in context
• Project Development vs Project Specification
CLOSING REMARKS