6. Vasarevicius Air Treatment PlasTEP 2012

8/18/2019 6. Vasarevicius Air Treatment PlasTEP 2012

1/99

ˇ

Part-financed by the European Union (European Regional Development Fund

COMPARISON OF DIFFERENT AIR TREATMENT METHODS

WITH PLASMA TREATMENT

PlasTEP 3rd Summer school and trainingscourse 2012 Vilnius / Kaunas

Saulius Vasarevicius, VGTU


2/99


3/99

3

Stationary Source Control

• Philosophy of pollution prevention (3P’s) – Modify the process: use different raw materials

– Modify the process: increase efficiency

– Recover and reuse: less waste = less pollution

• Philosophy of end-of-pipe treatment

– Collection of waste streams

– Add-on equipment at emission points

• Control of stationary sources – Particulates

– Gases


4/99

Three Types Of Control

Mechanical

Chemical

Biological


5/99

Particulate Control

(Mechanical)

• Electrostatic precipitator

• Bag house fabric filter• Wet scrubber

• High efficiency cyclones


6/99

Particulate Control Technologies

• Remember this order: – Settling chambers

– Cyclones

– ESPs (electrostatic

precipitators)

– Spray towers

– Venturi scrubbers

– Baghouses (fabric filtration)

• All physical processes


7/99

7


8/99

8

Settling Chambers

• “Knock-out pots”

• Simplest, cheapest, no moving parts

• Least efficient

– large particles only

• Creates solid-waste stream

– Can be reused

• Picture on next slide


9/99

9


10/99

Gravity settler

Disadvantages

• Large space requirement

• Relatively low overall collection

efficiencies (typical 20 - 60 %)


11/99

Flue Gas Cleaning – The state of the art

Selection criteria

ESP Bag house Scrubber Cyclones

(normal)

Spraycone

Cyclones

Emissionmg/Nm3 100 30 200 250 < 100

Reliability ++ + ++ ++++ ++++

Cost ++++ ++++ +++ + +


12/99

Gas Cleaning – The state of the art

Evaluation of ESP for industrial boilers:

• High cost (investment, maintenance & operation)• Complex large size plant with sub-systems

• Requires constant gas conditions (sulphur, temp, moisture)

Evaluation of bag filters for industrial boilers:

• High cost (investment, maintenance & filter bags)• Difficult to handle sulphur and sparks

• Not robust (one faulty bag destroys efficiency

Evaluation of wet scrubbers for industrial boilers:• High cost (large water treatment plant)• Difficult to separate fine particulate

• Sulphur control costly & difficult


13/99


Evaluation of cyclone “grid arrestor” :

• Low collection efficiency due to:

• Wrong design (see velocity analysis)

• Air ingress

• Bad manufacturing quality

• Lack of maintenance (blockage of cyclone cells)

But cyclone system advantages are low cost and robust installation

Can a cyclone reach efficiencies of ESP / Bag filter / Wet scrubber?

This question triggered our cyclone development Programin 1994 to improve cyclone efficiency and to invent the

“dry spray agglomeration principle”


14/99

Cyclone

•Most Common

•Cheapest

•Most Adaptable


15/99

Mechanical ollectors

yclones

Advantages: Good for larger PM

Disadvantages: Poor efficiency for finer PM

Difficult removing sticky or wet PM


16/99


17/99

17


18/99

Cyclone Operating Principle

“Dirty” Air Enters The Side.

The Air Swirls Around TheCylinder And Velocity IsReduced.

Particulate Falls Out Of The AirTo The Bottom Cone And Out.


19/99


20/99


Commercial applications of high efficiency cyclones:

BurnerMax

Fluidized bed furnace

High efficiency cyclonesoperating at 400 C


21/99

Multiple Cyclones

(Multi clone)Smaller Particles Need Lower

Air Flow Rate To Separate.Multiple Cyclones AllowLower Air Flow Rate, CaptureParticles to 2 microns


22/99

Air Filtration

Filt ti M h i


23/99

Filtration Mechanisms• Diffusion

Q: How does efficiency change withrespect to d p?

a. Efficiency goes up as dp decreases

b. Efficiency goes down as dp decreases

Filt ti M h i


24/99

Filtration Mechanisms• Impaction

Q: How does efficiency changewith respect to d p?

a. Efficiency goes up as dp decreases

b. Efficiency goes down as dp decreases

Filt ti M h i


25/99

Filtration Mechanisms• Interception

Fat Man’s Misery,Mammoth Cave NP

http://www.geocities.com/wrique2002/ParentsVisit/FatmansMisery2.jpg


26/99

Filter efficiency for individual mechanismand combined mechanisms

dp (m)

0.01 0.1 1 10

E f f i c

i e n c y

0.0

0.2

0.4

0.6

0.8

1.0

Interception

ImpactionDiffusion

Gravitation

Total


27/99

FILTRATION

Fiber filter

Q: Do filters function just as a strainer,

collecting particles larger than the strainer

spacing?a: yes

b: no

Filt D M d l


28/99

Filter Drag Model

s p f P P P P

V LVt K V K 21

Areal Dust Density LVt W

Filter drag

V

P S W K K S 21

K s

K e

K e & K s to be determined empirically

P f : fabric pressure drop P f : particle layer pressure drop

P s: structure pressure drop

Time(min)

P, Pa

0 150

5 380

10 505

20 610

30 690

60 990Q: What is the pressure drop after 100 minutes of

operation? L = 5 g/m3 and V = 0.9 m/min.

se


29/99

Case A: Pore blocking

Case B: Pore plugging

Case C1: Pore narrowing

Case C2: Pore narrowing w/lost poreCase D: Pore bridging


30/99

Air Filtration

• Impaction

• Diffusion

• Straining (Interception)• Electrostatics


31/99

Fabric Filter

(Baghouse)

•Same Principle As Home

Vacuum Cleaner•Air Can Be Blown Through Or

Pulled Through

•Bag Material Varies AccordingTo Exhaust Character

B


32/99

Cleaned gas

Dirty gas

Baghouse Filter –

only one to remove hazardous fine particles

Dust discharge

Bags


33/99

Advantages/Disadvantages

• Very high collection efficiencies

• Pressure drop reasonably low (at beginning of operation,

must be cleaned periodically to reduce)

• Can’t handle high T flows or moist environments


34/99

34


35/99

35

Pulse-Air-Jet Type

Baghouse


36/99


37/99

About Baghouses

Efficiency Up To 97+%

(Cyclone Efficiency 70-90%)Can Capture Smaller ParticlesThan A Cyclone

More Complex, Cost More ToMaintain Than Cyclones


38/99


39/99

Electrostatic Precipitators

Types include:

• Dry, negatively charged

• Wet-walled, negatively charged

• Two-stage, positively charged


40/99

• ELECTROSTATIC PRECIPITATOR

• Advantages of Electrostatic Precipitators

Electrostatic precipitators are capable very high efficiency, generally ofthe order of 99.5-99.9%.

Since the electrostatic precipitators act on the particles and not on the air,they can handle higher loads with lower pressure drops.

They can operate at higher temperatures.

The operating costs are generally low.

• Disadvantages of Electrostatic Precipitators

The initial capital costs are high.

Although they can be designed for a variety of operating conditions, theyare not very flexible to changes in the operating conditions, onceinstalled.

Particulate with high resistivity may go uncollected.


41/99


42/99

Electrostatic Precipitator Drawing

H A ESP O t


43/99

How An ESP Operates


44/99

44

ESPs

• Electrostatic precipitator• More expensive to install,

• Electricity is major operating cost

• Higher particulate efficiency than

cyclones

• Can be dry or wet• Plates cleaned by rapping

• Creates solid-waste stream

• Picture on next slide

El t t ti P i it t C t


45/99

45

Electrostatic Precipitator Concept

El t t ti P i it t


46/99

46

Electrostatic Precipitator

Cl d


47/99

Electrostatic Precipitator –

static plates collect particles

Dirty gas

Dust discharge

Electrodes

Cleaned gas


48/99


49/99

Scrubbers

•Gas Contacts A Liquid Stream

•Particles Are Entrained In

The Liquid•May Also Be A Chemical

Reaction

–Example: Limestone SlurryWith Coal Power Plant Flue Gas


50/99

Wet Particle Scrubbers

• Particulate control by impaction,

interception with water droplets

• Can clean both gas and particle

phases

• High operating costs, high

corrosion potential


51/99

• WET SCRUBBERS (CONTD.)

•Advantages of Wet Scrubbers

• Wet Scrubbers can handle incoming streams at high temperature, thusremoving the need for temperature control equipment.

Wet scrubbers can handle high particle loading.

Loading fluctuations do not affect the removal efficiency.

They can handle explosive gases with little risk.

Gas adsorption and dust collection are handled in one unit.

Corrosive gases and dusts are neutralized.

• Disadvantages of Wet Scrubbers High potential for corrosive problems

Effluent scrubbing liquid poses a water pollution problem.


52/99

52

Venturi Scrubber

Detail illustrates cloud atomization from high-velocity gas stream shearing liquid atthroat


53/99

53

V ti l V t i S bb


54/99

Vert ical Ventur i Scrubber


55/99


56/99


57/99

Tower Scrubber


58/99

58

Spray Towers

• Water or other liquid “washes out” PM

• Less expensive than ESP but more than

cyclone, still low pressure drop

• Variety of configurations

• Higher efficiency than cyclones

• Creates water pollution stream• Can also absorb some gaseous

pollutants (SO2)


59/99

59

Spray Tower


60/99

Gaseous Pollutant Control

• Absorption

• Adsorption

•Combustion

Control of Air Pollutants


61/99


Gaseous pollutants - Combustion• 3 types of combustion systems commonlyutilised for pollution control

– direct flame, – thermal, and

– catalytic incineration systems



62/99


Gaseous pollutants - Adsorption

• physical adsorption to solid surfaces

• Reversible - adsorbate removed from theadsorbent by increasing temp. or lowering

pressure• widely used for solvent recovery in dry

cleaning, metal degreasing operations,

surface coating, and rayon, plastic, andrubber processing



63/99


Gaseous pollutants - Adsorption• limited use in solving ambient air pollutionproblems – with its main use involved in the

reduction of odour

• Adsorbents with large surface area to

volume ratio (activated carbon) preferred

agents for gaseous pollutant control

• Efficiencies to 99%


64/99

64

Carbon Adsorption

• Will do demonstration shortly

• Good for organics (VOCs)

• Both VOCs and carbon can berecovered when carbon is

regenerated (steam stripping)

• Physical capture

– Adsorption

– Absorption


65/99

65


66/99



67/99


Gaseous pollutants - Absorption

• Scrubbers remove gases by chemical

absorption in a medium that may be a liquid

or a liquid-solid slurry

• water is the most commonly used scrubbing

medium

• Additives commonly employed to increasechemical reactivity and absorption capacity


68/99

Pollutants Of Interest

•Volatile Organic Compounds

(VOC)•Nitrogen Oxides (NOx)

•Sulfur Oxides (SOx)

Controlling Gaseous Pollutants: SO2 &


69/99

69

Controlling Gaseous Pollutants: SO2 &NOx

• Modify Process (recall 3P’s)

– Switch to low-sulfur coals

– Desulfurize coal (washing, gasification)

• Increase efficiency – Low-NOx burners

• Recover and Reuse (heat)

– staged combustion – flue-gas recirculation


70/99


71/99


72/99

Flue Gas SOx Control

SOx Forms Sulfuric Acid WithMoisture In Air Producing

Acid Rain.Remove From Flue Gas ByChemical Reaction With

Limestone

Control Technologies for Nitrogen


73/99

Control Technologies for Nitrogen

Oxides

• Preventive – minimizing operating

temperature

– fuel switching

– low excess air – flue gas recirculation

– lean combustion

– staged combustion

– low Nox burners

– secondary combustion – water/steam injection

• Post combustion – selective catalytic reduction

– selective non-catalyticreduction

– non-selective catalyticreduction


74/99

Thermal Oxidizers

For VOC Control

Also Called Afterburners


75/99

75

Thermal Oxidation

• Chemical change = burn – CO2 and H2O ideal end products of all processes

• Flares (for emergency purposes)

• Incinerators

– Direct

– Catalytic = improve reaction efficiency

– Recuperative: heat transfer between inlet /exit gas

– Regenerative: switching ceramic beds that hold

heat, release in air stream later to re-use heat

T T Of O idi


76/99

Two Types Of Oxidizer

•Catalytic

•Non-Catalytic


77/99

Thermal Oxidizer

(Non-Catalytic)

C l i Th l O idi


78/99

Catalytic Thermal Oxidizer

Biological Method


79/99

Biological Method

•Uses Naturally OccurringBacteria (Bugs) To BreakDown VOC

• “Bugs” Grow On Moist MediaAnd Dirty Gas Is Passed

Through. Bugs Digest TheVOC.

•Result Is CO2 And H2O

A Bi Filt F VOC R l


80/99

A Bio Filter For VOC Removal


81/99

E-beam flue gas treatment process


82/99

E beam flue gas treatment process(Prof. A.Chmielewski)


83/99

Pollutants removed by EB method

The method has been designed for simultaneous removal of:

• SO2

• NOx

• Cl, HF etc.

• Volatile Organic Hydrocarbons (VOC)• Dioxins

• Mercury

• Others…


84/99

Electron beam effect on gas, primary radiolysis products:

• 4.43N2 -› 0.29N2* + 0.885N(2D) + 0.295N(2P) + 1.87N(4S) + 2.27N2+ +0.69N+ + 2.96e-

• 5.377O2 -› 0.077O2* + 2.25O(1D) + 2.8O(3P) + 0.18O* + 2.07O2+ +

1.23O+ + 3.3e-

• 7.33H2O -› 0.51H2 + 0.46O(3P) + 4.25OH + 4.15H +1.99 H2O+ + 0.01H2+

+ 0.57OH+ + 0.67H+ + 0.06O+ + 3.3e-

• 7.54CO2 -› 4.72CO + 5.16O(3P) + 2.24CO2+ + 0.51CO+ + 0.07C+ +

0.21O+ + 3.03 e-


85/99

Electron beam effect on gas, secondary reactions:

• O(1D) + H2O ͢ ͢ ͢ ͢ -› 2OH*

• N2+ + 2H2O -› H3O+ + OH*+ N2

• O(3P) + O2+ M -› O3+ M

• e-+ O2 + M -› O2-+ M

• H3O+ + O2- -› HO2*+ H2O

As a result of these primary and secondary reactions OH*,

HO2 *, O*radicals, O3and other oxidizing species areformed, that can oxidize NO, SO2 and Hg.


86/99

SO2 removal pathways

Radiothermal:

• SO2 + OH* + M -› HSO3 + M

• HSO3 + O2 -› SO3 + HO2*

• SO3 + H2O -› H2SO4

• H2SO4 + 2NH3 -› (NH4)2SO4

Thermal:

• SO2 + 2NH3 -› (NH3)2SO2• (NH3)2SO2 -› (NH4)2SO4


87/99

NOx removal pathways

NO oxidation

• NO + O(3P) + M -› NO2+ M

• O(3P) + O2+ M -› O3+ M

• NO + O3+ M -› NO2+ O2+ M

• NO + HO2* + M -› NO2+ OH* +M

• NO + OH* + M -› HNO2+M

• HNO2+ OH* -› NO2+ H2O

NO2removal• NO2+ OH* + M -›HNO3+ M

• HNO3+ NH3-›NH4NO3


88/99

Reaction mechanisms and sequenceof E-beam process

H. Namba: Materials of UNDP(IAEA)RCA Regional Training Course on

Radiation Technology for Environmental Conservation TRCE-JAERI,

Takasaki,


89/99

VOC-decomposition and deodorization methods

Thermal Processes: 1-TO, Thermal Oxidation; 2-RTO, Regenerative Thermal Oxidation; 3-

Catalytic Oxidation with Recuperation. Filtering/Adsorption: 4-Biofilters; 5-Scrubber; 7-

Adsorption Container; 8-Concentrator Unit with TO; 9-Filtering. Non-thermal Oxidation: 6a-

Electrical Non-thermal oxidation; 6b-UVS Non-thermal Oxidation.

VOC d iti


90/99

VOC-decomposition

Non-thermal plasmas:• Decomposition of contaminants without heating

• Wide range of pollutants (Gases ... Particulate Matter PM)

• Decomposition of organic PM

• High efficiency for low contamination (e.g. deodorization), ([VOCs] < 1 g

Corg/m3)

Negative aspects:

• High energy cost/molecule_ high energy for high concentrations

• Uncompleted conversion and by-products _ low selectivity (CO2)

• Deposition of polymer films in reactors _ unstable plasma source

Possibilities - indirect treatment, hybrid methods = combination of plasma with:

catalysts, scrubbing, adsorbents…


91/99


92/99


93/99


94/99

Non thermal plasma


95/99

PDC for deodorization (commercial)

1200 By-products


96/99

Total weighed environmental impact of plasma and non-plasma end-of-pipe

pollutant treatment technologies: the comparison of technologies for SOx/NOx

removal. 1) Electron Beam Flue Gas Treatment (EBFGT) versus 2) Wet Flue Gas

Desulphurization with Selective Catalytic Reduction (WFGD+SCR

1099.7

74.4

0

200

400

600

800

1000

1200

EBFGT WFGD + SCR

C M L 2 0 0

1 ,

E x p e r t s I K P ( C e n t r a l E u r o p e

)

By products

Material resources

Electricity

Material resources


97/99

Total weighed environmental impact of plasma and non-plasma end-of-pipe

pollutant treatment technologies: the comparison of technologies for VOCs

removal. 1) Dielectric barrier discharge (DBD) versus 2) adsorption by zeolite (for

LCA) and molecular sieves (for CBA), 3) biofiltration,

4.2

41.1

26.1

0

10

20

30

40

C M L

2 0 0 1 ,

E x p e r t s I K P ( C e n t r a l E u r o p e )

Material resources

Electricity


98/99

Flue gas treatment method >300

MW unit

Investment costs

€/kW

Annual operation costs

€/MW

EBFGT

32-45

1290-1577

Wet deSO2 + SCR 176-247 4786-5350

Wet deSO2 + SNCR 144-190 3870-4223

Emission control method 120 MW

unit

Investment costs

€/kW

Annual operation costs

€/MW

EBFGT

113

5167

WFGT+SCR 162 5343

Investment and operation costs of EBFGT and combination of conventional deSO2 and deNOx

Full “Report on Eco-Efficiency of Plasma-Based technologies for Environmental Protection” and

“Report on cost-benefit analysis of plasma-based technologies“ are available at the PlasTEP

project website (http://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-

efficiency_report.pdf , http://www.plastep.eu/fileadmin/datein/Outputs/120208_CBA.pdf ).

http://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/datein/Outputs/120208_CBA.pdfhttp://www.plastep.eu/fileadmin/datein/Outputs/120208_CBA.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdfhttp://www.plastep.eu/fileadmin/dateien/Outputs/OP3-2.1_Eco-efficiency_report.pdf


99/99

Thank You for Your attention!

6. Vasarevicius Air Treatment PlasTEP 2012

Documents

Transcript of 6. Vasarevicius Air Treatment PlasTEP 2012