eng3003_seminar_2_waste_identification_and_minimisation.pptx

Environment and
Sustainable Processing

1. Environment and Sustainable Processing Dr Omar Aboelazayem

2. Seminar 2 Waste identification and minimisation and solid waste management

3. Waste identification and minimisation

4. Questions Suggest potential engineering solutions to minimise waste formation from reactors. Identify some of the waste sources from separators

5. Questions Suggest potential engineering solutions to minimise waste formation from reactors. Chemistry of process route Sample solution towards cleaner chemistry: Developing synthesis pathways using alternative feedstock Alternative solvents to replace organic solvent Alternative reaction conditions (lower T and P) Use of improved catalyst Alternative chemical products (safer and less toxic)

6. Questions Suggest potential engineering solutions to minimise waste formation from reactors. Impurities in feed Sample solution: Remove impurities prior entering reactor feed stream i.e . use of strong base resins to absorb impurities from hydrocarbon stream prior catalytic reactor

7. Questions 2. Identify some of the waste sources from separators Waste from dryer Solids loss through entrainment of gas Fouling on heat transfer surfaces Waste from filter Cake washing (contamination of wash liquor) Disposal of filter medium/aid (e.g. filter bag) Filtrate contamination due to filter medium failure

8. Questions 2. Identify some of the waste sources from separators Waste from centrifugal separation Solids washing and spillage Waste from absorption Contamination of effluent gas due to incomplete gas absorption Solvent entrainment in effluent gas Contamination of recirculating solvent by dissolved species or corrosive product

9. Questions 2. Identify some of the waste sources from separators Waste from distillation: Non-condensable accumulate in condenser Non-volatiles accumulate in reboiler Fouling of trays and heat transfer surfaces

10. Solid Waste Management

11. Questions What are some of the engineering solutions to improve heat recovery efficiency of a boiler system to effectively recover heat from waste incineration? What are some of the biological and physical-chemical treatment methods that can be used for leachate treatment? What are some of the applications of recovered landfill gas? What are the challenges of using landfill gas?

12. Questions What are some of the engineering solutions to improve heat recovery efficiency of a boiler system to effectively recover heat from waste incineration? To increase heat recovery efficiency: Boiler tubes should be arranged parallel to gas flow to reduce fouling and corrosion Scale deposits can be removed using soot blowers (using superheated steams), shot cleaning ( dropping cast iron shots onto the tubes to knock off the deposits) Temperature control in the boiler to reduce high- and low-temperature corrosion

13. Questions What are some of the biological and physical-chemical treatment methods that can be used for leachate treatment? Biological methods: Activated sludge Aerated lagoons Anaerobic Physical-chemical methods: Coagulation/precipitation Chemical oxidation Ion exchange Adsorption Reverse osmosis

14. Questions What are some of the applications of recovered landfill gas? Boilers and other direct combustion applications Easiest and cheapest option Direct use of landfill gas to replace/supplement coal, oil, natural gas i.e. boiler firing, sludge and leachate drying, incineration, cement and brick kilns Electrical power generation Use in internal combustion engine or gas turbine Potential engine and vehicle fuel Required clean-up to natural gas standard

15. Questions What are the challenges of using landfill gas? Presence of trace gases (hydrocarbons), H2S and water vapour in landfill gas are corrosive towards turbine engines and internal combustion engine. Also harmful if used as vehicle fuel. Require cleanup technology: filtration, scrubber Large amount of soil and particulate matter cause buildup in oil and clogging in engines Require gas filtration or gas refrigeration (less common)

16. Questions ?