MICROREACTORS AND MICRO HEAT EXCHANGERS_104817.pptx

Microreactors and micro heat exchangers

1. MICROREACTORS AND MICRO HEAT EXCHANGERS AN INTRODUCTION

2. INTRODUCTION Process intensification (PI) is a chemical engineering technique aimed at improving efficiency, productivity, and sustainability in the design of chemical processes. One aspect of PI is the use of miniaturization, which essentially entails reducing the size of equipment and processes. This presentation focuses on microreactors and micro heat exchangers as two key technologies for PI.

3. NECESSITY The world is currently moving towards miniature equipment due to different attractive features such as Cost Reduction Proven reliability Enhanced cooling performance Energy efficiency

4. SECTION A: MICROREACTORS

5. WHAT ARE THEY Micro reactors are devices where chemical reactions take place is channels with an inner diameter of less than 1mm. They consist of pumps, micromixers followed by tubes or channels and the quenching zone. Their smaller dimensions increase surface area to volume ratio which results in higher mass and heat transfer.

6. TESTING Design verification Using computer simulations Reactor performance tests Flow tests Maximum throughput testing Heat transfer efficiency tests Reaction selectivity and conversion Catalyst lifetime and performance Determining residence time distribution (RTD)

7. Testing… Material and structural integrity tests Leak testing Chemical compatibility Mechanical stress testing Thermal stability

8. APPLICATIONS 1. Food processing for emulsification and fermentation processes 2. Used in fuel cells to convert chemical energy to electrical energy 3. U sed in water treatment like water softening and removal of contaminants 4. catalyst development 5. Enhance heat and mass transfer 6. Applicable in biomolecule synthesis like protein synthesis

9. SECTION B: MICRO HEAT EXCHANGERS

10. WHAT ARE THEY Micro heat exchangers are small scale heat exchangers in which fluid flows in lateral confinements also known as micro channels with dimensions less than 1mm. Micro channels in heat exchangers have high surface area to volume ratio which increases the heat transfer. Their compact size make them ease to be integrated into other compact systems like electric devices as a cooling system.

11. FABRICATION Microreactors and micro-heat exchangers generally use the same fabrication techniques . 1. Micromachining Uses precision tools (e.g., lasers, milling) to cut and shape materials at micro-scale. Materials used : metals , silicon , polymers and ceramics Construction Laser machining (vaporizes or melts materials ) Mechanical milling (precise cutting) Electrical discharge machining (EDM) (removes material with electrical sparks ) 2. Etching Methods Wet etching uses chemical solution to remove material from the substrate Dry etching uses plasma or gases in a vacuum Materials used : glass , silicon ,metals ,polymers

12. CONT… Construction : In wet etching exposed material dissolves leaving desired pattern while in dry etching plasma or gases etch precise and intricate pattern on material 3. Molding Material is shaped by pouring or pressing it into a mold Materials used : Polymers, metals , silicon , ceramics Construction : Lithographic molding , galvanoforming(electroplating) , abforming (pressure /heat ) 4. Lithography Light is used to transfer patterns onto a photoresist layer on a substrate Materials used : Silicon , glass , photoresist Construction : Application of photoresist to substrate , exposure to UV-light through a mask then develop to remove unexposed areas

13. TESTING Thermal performance testing Pressure drop and flow characteristics Structural integrity and leak testing Fouling and durability testing Simulations

14. APPLICATIONS Micro-distillation Controlled cooling Microreactors Temperature control in pharmaceutical processes

15. CONCLUSION Micro-reactors and micro heat exchangers are an alternative to conventional reactors and heat exchangers with better process performance and reduced capital and operational costs. They cater to the need for improved heat and mass transport phenomena, chemical reaction kinetics and control of thermodynamics.