WP6: Reactor Design and scale-up

6 months meeting, videoconference25th July 2013

Workpackage:

Presenter:

Collaborating teams:

WP6: Reactor Design and scale-up

Dr. Javier Marugán (URJC)

MTECUoBVAST-ICTSIRIM


Description of work6.1. Photoreactor optimization (URJC, MTEC)

6.1.1. Opto-mechanical simulation6.1.2. Experimental validation

6.2. Solid-state LED reactor optimization (UoB,MTEC)6.3. Kinetic modelling and scale-up (URJC, UoB)

6.3.1. Intrinsic kinetic modelling6.3.2. Reactor design

6.4. Field testing (VAST-ICT, MTEC, SIRIM)


Position in Project

Task 6.2LED, material &

reactor design opt.WP2.2Novel Visible

Light Active Mat.

WP3.3UV LED Matching

Selection

WP2.1:Catalytic Discovery

WP8.2Technical

Documentation

WP7.3Process Life Cycle

Assessment

Task 6.1Photo-catalytic

Structure Optim.

Task 6.4Field

Testing

Task 6.3Kinetic Modelling

and Scale-up


WP6 Milestones (none on M1-M6)- MS26) Impact of reactor geometry calculated by simulation and

validated experimentally (URJC, M18)- MS27) Identification of best catalyst scaffold for incorporation in the final

reactor (UoB, M27)- MS28) Initial kinetic models of photo-reactor performance determined

(URJC, M27)- MS29) LED array-photo-catalytic reactor constructed (UoB, M30)- MS30) Pilot system connected and initial results from field testing

obtained (SIRIM, M36)

WP6 Deliverables (none on M1-M6)- D6.1) Catalyst morphology (URJC, M30)- D6.2) UV-LED reactor design (UoB, M45)- D6.3) Kinetic model for reactor (URJC, M42)- D6.4) Reactor field testing (SIRIM, M48)


Action Plan M1-M6 (kick-off meeting)- Optomechanical simulation and evaluation of

radiation absorption with standard catalyst of the standardized reactor designed in WP4


Description of work – 1M-6M6.1. Photoreactor optimization (URJC, MTEC)

6.1.1. Opto-mechanical simulation6.1.2. Experimental validation

6.2. Solid-state LED reactor optimization (UoB,MTEC)6.3. Kinetic modelling and scale-up (URJC, UoB)

6.3.1. Intrinsic kinetic modelling6.3.2. Reactor design

6.4. Field testing (VAST-ICT, MTEC, SIRIM)

Task 4.1.Test Reactor


6.1. Photoreactor optimization – 1M-6M- Estimation of the distribution of light inside the photoreactor

to maximize the average LVRPA.

- Inputs: Geometry of reactorGeometry of solar collector / LED systemRadiation power and spectrum Optical properties materials / CATALYSTS

- Validation: Model organic chemicals degradationModel bacteria inactivationRadiation measurements

- Optimization of the configuration of the catalyst


Standardisation of Test Conditions 1.- Preliminary radiation calculations

Simulations performed with these main assumptions.• 1 central LED (D = 40 mm) and 8 LED (D = 10 mm)

equally distributed.• Emission power: 48 W/m2 of UV-A (highly value of solar

irradiation). That would correspond to approximately to 150 and 10 mW electrical power LED respectively with 40% of efficiency of electricity to light conversion.

• Direct / Diffuse radiation source• Transparent / Specular / Diffuse Reactor wall• Catalyst disc (D = 40 mm) place at 100 mm below the

LED array.



• Direct radiation source• Transparent Reactor wall

Average incident radiation flux at the catalyst surface:

> 30 W/m2

Highly non-homogeneous



• Diffuse radiation source• Transparent Reactor wall

Average incident radiation flux at the catalyst surface:

< 5 W/m2


To be determined

Standardisation of Test Conditions

• Dimensions of the light source and cooling system

• Dimensions of the immobilized catalyst

• Number, dimensions and arrangement of the LED.

• Emission geometry, power and spectra of the LED.

• Optical characteristics of the reactor materials and surfaces, mainly the outer reactor wall.

High Efficacy 365nm UV LED Emitter LED Engin LZ1-00U600


Standardisation of Test Conditions 2.- UV-A LEDs radiation calculations

Suggested arrangement for 12 LZ1-00U600 LEDs in a support plate:

Plate = 60 mm (diam.)Foot print = 4.4 x 4.4 mmLED = 3.2 mm (diam.)Separation = 6 mm


Standardisation of Test Conditions 2.- UV-A LEDs radiation calculationsCase A: Reactor = 90 mm (diam.) Catalyst disc = 40 mm (diam.) Distance = 50 – 180 mm Wall: Transparent / Specular

Case B: Reactor = 90 mm (diam.) Catalyst disc = 60 mm (diam.) Distance = 50 – 180 mm

Wall: Transparent / Specular



Catalyst = 40 mmTransparent Wall

% of radiation emitted by the LEDsDistance (mm) Catalyst Bottom Wall

50 17,91 39,47 42,6570 10,53 28,12 61,37

100 5,71 17,35 76,98120 4,08 13,12 82,83150 2,69 9,09 88,24180 1,91 6,58 91,53

Catalyst = 60 mmTransparent Wall


50 34,11 23,35 42,5770 20,85 17,67 61,49

100 11,75 11,32 76,95120 8,53 8,61 82,87150 5,71 6,04 88,26180 4,06 4,40 91,56

Radiation Balance (%)



Catalyst = 40 mmSpecular Wall


50 28,48 71,53 0,0070 29,67 70,33 0,00

100 29,51 70,49 0,00120 29,63 70,37 0,00150 28,69 71,32 0,00180 27,54 72,46 0,00

Catalyst = 60 mmSpecular Wall


50 55,82 44,18 0,0070 57,41 42,60 0,00

100 57,38 42,62 0,00120 58,42 42,11 0,00150 56,49 43,47 0,00180 54,99 45,01 0,00

Radiation Balance (%)



Radiation Flux



Catalyst = 40 mm

Transparent Wall

Catalyst = 60 mm

Transparent Wall

LED Emission = 160 mW (Data from 2011 LED Engin Catalog)

W/m2

Distance (mm) Catalyst50 268,0470 157,68

100 85,43120 61,10150 40,30180 28,54

W/m2

D (mm) Catalyst50 225,4970 137,87

100 77,66120 56,39150 37,73180 26,87

Catalyst = 40 mm

Specular Wall

Catalyst = 60 mm

Specular Wall W/m2

D (mm) Catalyst50 426,2270 444,11

100 441,76120 443,55150 429,37180 412,20

W/m2

D (mm) Catalyst50 369,0470 379,54

100 379,38120 386,26150 373,44180 363,54

Radiation Flux (W/m2)



Radiation Flux Distribution

Transparent Wall Specular Wall

Catalyst = 40 mm, Distance = 120 mm



Main Conclusions- Working with a bigger catalytic disc decrease the average radiation flux,

inherently unhomogeneous, although would reduce the experimental error in the determination of the reaction rate.

- Increasing the reflective properties of the wall increases significantly the radiation flux and reduces the non-radial unhomogeneities and the influence of the distance to the LED array.

- Even in the worst scenario, with the lower value of the typical emission provided by the manufacturer , transparent walls and the biggest disc the irradiation flux is in the order of the 30-40 W/m2 UV-A solar irradiation of a sunny day.

- The possibility of modifying the distance would allow working under different irradiation conditions and with different liquid volumes.


Standardisation of Test Conditions

To be determined (Task 4.1)

• Number, dimensions and arrangement of the LED.

• Proposed dimensions for the test reactor.


LEDs arrangement

Standardisation of Test Conditions 3.- Radiation calculations in the proposed test reactor


Incident radiation at the bottom (no absorption)

Standardisation of Test Conditions 3.- Radiation calculations in the proposed test reactor

Assumption for emission:

32 LEDs x 0.160 mW = 5.76 W of UV-A


Catalyst in suspension

Standardisation of Test Conditions 3.- Radiation calculations in the proposed reactor

CTiO2 (g/L) Absorption Coef.κ (m-1)

Scattering Coef.σ (m-1)

0.02 21.416 93.0380.05 53.540 232.600.1 107.08 465.190.2 214.16 930.380.5 535.40 2326.0

Catalyst: AEROXIDE® P25 TiO2 (Evonik Industries AG)Optical properties (Manassero et al., Chem. Eng. J. 225 (2013) 378–386):

Specific Absorption Coefficient (λ=360nm): κ* = 10708 cm2/gSpecific Scattering Coefficient (λ=360nm): σ* = 46519 cm2/g

Estimated Absorbed Radiation (W)

0.3710.3990.4520.5620.816


Immobilized Catalyst

Incident Radiation = 0.998 W



Immobilized CatalystCatalyst: AEROXIDE® P25 TiO2 (Evonik Industries AG)Optical properties (unpublished experimental results from URJC) :

Absorption Coefficient (λ=360nm): κ = 8818 cm-1

d (mm)Absorbed

radiation (W)0.1 0.08420.2 0.16140.5 0.35581.0 0.58482.0 0.82695.0 0.9859

10.0 0.9979

Optimal absorption P25 TiO2 = 2 – 5 mm



Conclusions


The proposed reactor design should provided comparable results between the experiments carried out by the different groups, allowing the use of the obtained data for the rigorous kinetic modeling of the process.

The absorption of radiation should be high enough to allow fast reaction rates of degradation.

However, the expected decrease in the quantum yield due to the increase in the recombination rate at such high values of irradiation power could reduce significantly the efficiency of the process.


Next actions:- Experimental validation- Kinetic Modelling- Estimation of the experimental reaction rate.

Documents

WP6: Reactor Design and scale-up