Fluidized bed reactor with alkali aggregate.pptx

Fluidized bed reactor

1. BMS COLLEGE OF ENGINEERING BENGALURU – 560 019 Presentation on FLUIDIZED BED REACTOR By HARSHITHA . K 3 rd Sem , M.Tech - Environmental Engineering USN: 1BM2 1 CEE0 7 BMS College of Engineering 1

2. CONTENT 2

3. INTRODUCTION A  fluidized bed reactor  ( FBR ) is a type of  reactor device that can be used to carry out or perform a wide range of  multiphase chemical reactions. In this type of reactor, a  fluid (gas or liquid) is passed through a solid  granular material (usually a  catalyst ) at high speeds enough to suspend the solid and cause it to behave as though it were a fluid. This process, known as  fluidization . Fig 1: Fluidized Bed Reactor Source: Studocu.com 3

4. WORKING PRINCIPLE The solid substrate material in the fluidized bed reactor is typically supported by a  porous plate, known as a distributor. The fluid is then forced through the distributor up through the solid material. At lower fluid velocities, the solids remain in place as the fluid passes through the voids in the material. This is known as a  packed bed  reactor. As the fluid velocity is increased, the reactor will reach a stage where the force of the fluid on the solids is enough to balance the weight of the solid material. This stage is known as incipient fluidization and occurs at this minimum fluidization velocity. Once this minimum velocity is surpassed, the contents of the reactor bed begin to expand and swirl around much like an agitated tank or boiling pot of water. The reactor is now a fluidized bed.  The Fluidized Bed reactor incorporates an up flow reactor partly filled with sand or a low density carrier such as coal or plastic beads. A very large surface area is provided by the carrier material for growth of biofilm. Fig 2: Fluidized bed reactor showing the media in motion Source: Cpheeo.gov.in 4

5. Advantages Uniform particle mixing Uniform temperature gradients Continual operation of reactor A utomatically controlled operations Maintenance is very low Even temperature distribution eliminates hot spots Catalyst is easily replaced or regenerated More efficient contacting of gas and solid than in other catalytic reactors Proven system Disadvantages Increased reactor vessel size Pumping requirements and pressure drop Particle entrainment Lack of current understanding Erosion of internal components Pressure loss scenarios Expensive to construct and maintain Regeneration equipment for catalyst is expensive Catalyst may be deactivated Can’t be used with catalyst solids that won’t flow freely Attrition, break-up of catalyst pellets due to impact against reactor walls, can occur ADVANTAGES AND DISADVANTAGES 5

6. OPERATIONAL PROBLEMS 6 Operation & control of fixed bed reactor is easier than fluidized bed reactor. Because fluidized bed reactor needs precise control of reactor pressure, flow rates and temperature to ensure efficient fluidization of the catalyst. A pressure disturbance can cause loss of catalyst through cyclones. And this carryover of catalyst with product gases will choke the reactor down stream and you need to shutdown the plant for cleaning of equipment, such as venturi scrubber, condenser, connecting pumps, filters and piping. In case of inlet gases flow interruption catalyst may seep below the catalyst support grid and will chock the bottom of reactor. The fluid-like behaviour of the fine solid particles within the bed eventually results in the wear of the reactor vessel. This can require expensive maintenance and upkeep for the reaction vessel and pipes. If fluidization pressure is suddenly lost, the surface area of the bed may be suddenly reduced. The high gas velocities present in this style of reactor often result in fine particles becoming  entrained  in the fluid.

7. 7 MAINTENANCE STRATEGIES FBR requires maintenance once or twice a year to ensure proper operation Maintenance and inspection of the reactor and its components involves cleaning, repairing, replacing, or upgrading the parts that may be subject to wear, corrosion, fouling, or damage, as well as checking the integrity and functionality of the reactor structure, equipment, and instruments.  M easuring and regulating the key parameters, such as temperature, pressure, flow rates, composition, and bed height, as well as detecting and correcting any deviations or malfunctions that may affect the reactor stability or efficiency. The monitoring and control system should be able to handle the inherent nonlinearity, uncertainty, and dynamics of the FBRs, as well as to cope with the disturbances and uncertainties in the feedstock, catalyst, and ambient conditions. For this purpose, various techniques and strategies, such as sensors, actuators, feedback, feedforward, adaptive, and model-based control, can be employed to ensure the optimal and safe operation of FBRs. Moreover, the maintenance and inspection should follow the established protocols and standards, such as the American Society of Mechanical Engineers (ASME) codes, the Occupational Safety and Health Administration (OSHA) regulations, and the International Organization for Standardization (ISO) guidelines, as well as the specific requirements of the reactor manufacturer, operator, and regulator.

8. 8 REFERENCES https://encyclopedia.che.engin.umich.edu/fbr/ https://www.chemengghelp.com/fluidized-bed-reactor-system/ https://www.linkedin.com/advice/1/what-best-practices-standards-safety?trk=article-ssr-frontend-x-article_more-articles_related-content-card https://www.netsolwater.com/the-technology-of-fluidized-bed-reactors-in-sewage-treatments-plants.php?blog=2058 https://envirogen.com/products/biological-treatment-liquid-phase/fludized-bed-reactor-fbr/#gref

9. 9 THANK YOU