Photo-catalytic Reactors

Photocatalytic Reactors
Double Skin Sheet Reactor
Thin Film Bed Reactor
Parabolic Trough Reactor
Advantages
Advantages
Advantages

Total global UV-irradiation usable
Good mass transfer.

Nearly closed reactor so no vaporization .

Simple construction.

Low investment costs

Total global UV-irradiation usable.
High optical efficiency
Effective transfer of oxygen into the water film
No separation of TiO2 from the purified water needed
Simple construction
Low investment costs

Good mass transfer.

Nearly closed reactor so no vaporization of volatile contaminants

1.Tube light reactor (TLR).

It is the new kind of non-concentrated reactor.

It consist of a flat and transparent structured box in which a suspension of the photocatalyst circulates driven by a pump.

A number of different designs of non concentrating
solar reactors have been proposed which includes trickle down flat plate ,tubular flat plate, pressurized flat plate and shallow solar ponds

1.2. Double Skin Sheet Reactor
1. Solar Photocatalytic Reactors
Photocatalysis uses only solar UV radiation, which accounts for 4%–6% of total solar radiation. Fifty percent or more of UV radiation is in the diffuse radiation especially at humid areas and during cloudy days. Thus, PTR does not function efficiently during cloudy and overcast days.
As temperature increases, solubility of oxygen in water decreases leading to bubble formation continuous supply of oxygen to reaction solution is essential.




1.1. Parabolic Trough Reactor ….cont'd
1. Solar Photocatalytic Reactors
Double Skin Sheet Reactor
Thin Film Bed Reactor
Parabolic Trough Reactor
Disadvantages
Disadvantages
Disadvantages

Separation of TiO2 from the purified water needed.

Large reactor area necessary for the purification of large waste water volumes

Laminar flow conditions so mass transfer limitation possible
Large catalyst area necessary for the purification of large waste water volumes
Catalyst not protected against pollution

Only direct UV-irradiation utilizable
Low optical efficiency
Separation of TiO2 from the purified water needed
Overheating leads to leaks and corrosion sources
High investment costs

Water bell photocatalytic reactor in which water pass through a nozzle forming water bell flows around a vertical UV lamp.

Use of a reflecting surface mounted beneath the lower side of the fountain allows the water thin film to be irradiated from both sides.

Eliminating the need for additional aeration system.

Fountain reactor works on a continuous mode
2.Fountain Photo catalytic Reactor
Introduction

Reactor Concept

Types of Photocatalytic Reactors
1. Solar Photocatalytic Reactors
1.1. Parabolic Trough Reactor
1.2. Double Skin Sheet Reactor
1.3. Thin Film Fixed Reactor
1.4. Step Reactor
1.5. Tubular Reactor
.2. Artificial Photocatalytic Reactors
2.1.Basic components
2.3. Artificial Photo catalytic Reactors types

Content

Step photoreactor is based on cascade thin-film principal. It is a stainless steel staircase having 21 steps, covered with a glass sheet


TiO2 is deposited on a flexible support of paper using a silica-based inorganic binder. The coating method is patented.


Need for reaction solution purging with oxygen or oxidants addition as well as regular cleaning.

1.4.Step Photoreactor

fountain reactor



2. Artificial Photocatalytic Reactors
Method Of Design

The fixed bed reactor system can use the solar photons without further concentration.

This type employs both the direct and diffuse portion of the solar radiation.

The thin film fixed bed reactor consisted of a TiO2 coated glass plate with an effective surface area.

Once the catalyst is fixed on an inert surface there is no need to remove the photocatalyst from the cleaned liquid.

1.3. Thin Film Fixed Reactor

1. Solar Photocatalytic Reactors
Use micro porous catalyst structure

Advantages
excellent temperature control
excellent flow rate control

Disadvantages
small throughput
Department of Materials Science
Institute of Graduate Studies and Research
Alexandria University



Advantages
high flow rate with low pressure drop
easy to scale up

Disadvantages
difficult illumination of the channels
could be overcome with nano scale illumination

Types of Photocatalytic Reactors
3.Fluidised Bed Reactor

THANK YOU

Advantages
high mass transfer coefficients
relative ease of scale up
Disadvantages
non-uniform illumination
(could be overcome with nanoscale illumination)

Department of Materials Science
Institute of Graduate Studies and Research
Alexandria University
How to overcome the mass transfer barrier?
Photon transfer:
Light intensity decays with distance due to absorption on the way
Solved by getting light source close to catalyst

Mass transfer :
Presence of good contact between pollutants and the catalyst
Solved by improved designs

3.Fluidised Bed Reactor
A fluidized bed photoreactor using TiO2 coated on floating ceramic spheres.

The reactor operated in a batch mode.

Continous supply of air.
10-fold increase of the illuminated catalyst surface per unit volume of reactor compared to an annular reactor
Drawbacks:
Decay of light( maximum length is 5cm)
Fiber volume

How to overcome the photon transfer barrier?


LED devices
robust, long-lasting
low-energy consuming


Luminescent molecules interspersed with catalyst (under investigation)
Department of Materials Science
Institute of Graduate Studies and Research
Alexandria University
Different reactor configurations have been used to degrade various types of pollutants using solar light or artificial light simulating sunlight.

II. Evaluation Criteria
Reactor throughput.
For solar reactors, aperture area is area in which solar radiations enter the reactor while gross area is area based on reactor outer dimensions.
Ease of catalyst removal from treated effluent.
Cost.



I. Introduction
Parabolic Trough reactor (PTR) consists of a transparent pipe through which contaminated water flow. The pipe is located at the focal line of a collector that is a parabolic light-reflecting surface.

Installation of PTRs requires additional large area to avoid PTR modules projecting shadows on each other.



1.1. Parabolic Trough Reactor

1. Solar Photocatalytic Reactors











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3/25/2017

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