Hot Microbubble Injection in Thin Liquid Layers for Ammonia – Water Separations Pratik Desai AMIChemE AMInstP GradEI Professor William B S Zimmerman BSc PhD
Problem Description S Ammonia in Leachate is an environmental hazard - Lowering Ecotoxicity - Requires High Cost for Ammonia Removal! EQS = 0.39 mg/l, landfill conc. = 50-3000 mg/l S Ammonia Production (Haber-Bosch) is energy intensive -High Pressure , Low Temperature S 2 % of world’s energy used for ammonia production , 0.5% used for remediation. Ammonia used for several products – fertilisers, adjuvants, fuels, explosives, high value chemicals
Proposed Solution Tackle problem in two steps Design new microbubble unit operation – Microbubble Stripping Lower leachate ecotoxicity by ammonia recovery & try to sell ammonia either as a pure product or upgrade it and sell it as a more valuable chemical via Desai-Zimmerman MMARP
Research Interest - Publications Increase in publication on ammonia removal from landfill leachate. Source: Scopus
1. Identification of key performance indicators S Processing Time designated as Indicator (Efficiency as well) S Variables decided – Benchmarking to be performed once results are obtained
Microbubbles (Mb) > 1µm <1000 µm >HX & MX for smaller bubbles ( >> SA/V ratio) Microbubble Generation - requires surface energy
Fluidic Oscillator No-moving part bi-stable diverter valve – Several benefits
Fluidic Oscillation Reduces Bubble Size Oscillatory Bubble Formation Steady Flow Bubble Formation
Block Diagram
Hypothesis - Basis Temperature gradient (Ethanol-Water) Concentration gradient (Ammonia-Water)
identification of operational parameters Ammonia -Water used for identifying operational parameters Selected as main performance together with efficiency – Shorter the processing time, greater is the throughput possibility!
Experimental Design S Factorial Design of Experiment Runs determined by the interaction between the different effects and therefore lot more information obtained from the same set of data obtained differently!
Set up Schematic FI TI TI MICROBUBBLE GENERATION (HXRig) TI TI ELECTRIC HEATER FLUIDIC OSCILLATOR DIFFUSER TC TI FC PC AIR INLET BLEED VALVES
S Sintered Steel Sparger – S Inexpensive S Bespoke design based on calculations S Material Selection – Sintered SS – Durable , easy to manufacture, possibility to make it really thin μ – 100 m S Low pressure drop- 20 mbar – Calculations from Holdich et al ,2006 – maintained by larger orifice μ – 100-150 m , greater porosity & thinner sparger
Key Results - Ammonia - Water S Very effective separation observed for Ammonia Water! S Operational conditions identified for leachate
Possibly reduced need for Caustic! Removal at pH < 9 still achieved. ↔ NH3 + H2O NH4+ + OH- Bubbles are vapourising water and driving equilibrium towards ammonia generation
What happens to Mass Transfer Coefficients ? S KD is on the 101 magnitude. S Srinath and Loehr (1974) report KD on the 10-3 magnitude; Smith and Arab (1988) between 10-3 and 10-2. 1000 times greater mass transfer!
2. Do Hot Microbubbles mediated by FO work for Ammonia Removal in Leachate ? YES!
Three modes of operations
Where we are compared to others? Cheung et al. (1997) 100 Silva et al. (2004) Marttinen et al. (2002) Kabdasli et al. (2000) Stripping efficiency (%) 80 Cheung et al. (1997) Cheung et al. (1997) Marttinen et al. (2002) 60 Collivignarelli et al. (1998) 40 Stripping Adsorption 20 Chemical precipitation Oxidation 0 0.1 1 10 100 1000 Processing time (h)
Latest modifications 15,000 times for some ammonia rich liquors!
MMARP – Waste Factory Microbubble Mediated Ammonia Recovery Processes Pratik D Desai Professor William B J Zimmerman
Desai-Zimmerman MMARP Ammonia converted to other products – 1. Pall Knorr Synthesis - Grantham Scholar co-supervised by WBJZ and PD – High Value product Flue Gas enriched using 2. Conversion to Tuneable salts- IIKE2 Scale up – Energy FO mineral carbonation/ Cat Ammonia 3. Used as fertilizer via microbubble condenser (Project running) 4. Upgraded via plasma microreactor(depends on today) Biomass used for AD – 5. Used as a source for MAC growth by in situ urea Energy plus CHP – conversion – Patent pending – work proceeding from IIKE Lipid rich MACs to be Energy Catalyst 1 and IIKE 2 used for energy recovery Mb Intervention 3 – Microbubble condenser Ammonia Removal, COD/BOD Reduction, Removal of Heavy Metal Separation of MAC & Heavy Metal Ion Densi ication and Increase Leachate Ions & Need for BOD/ Recovery of Metals, Micro lotation in Optical Transparency COD, Lipid Production Sewering the remnant off. Mb Intervention 2 – Mb Intervention 4 – Increased Growth Rate Algal flotation and separation Mb Intervention 1 – Preprocessing
What happens to the recovered Ammonia? We can make Carbamate at RT and Atm P without catalyst. 50% Ratio but tuneable – Carbamate and Carbonate. 70% conversion per pass. H 2 N O OH HN N + NH 3 ( aq ) OH 2 OH 3 R 1 R 2 + NH 3 ( aq ) R 1 R 2 N Optimise to select for mono- di- tri-ethanolamines O O H O OH High value chiral Stable aromatic products + NH 3 ( aq ) HO HO NH 2 intermediates Scheme 1 Relatively poor aqueous solubility Scheme 2
Microbubble Anaerobic Digestion fit into MMARP S CO2 injection can cause 110% (unoptimised) increase in production rate for biogas ( untreated wet foodwaste) S We can sustainably recover ammonia from ammonia rich liquor. S We can generate tuneable salts of carbamate and carbonate at RT/AtmP and this is exothermic and this can sequester CO2 S Combining these concepts together, we have a sweetening process and a reduced CAPEX ,increased payback AD with process integration
Innovate UK Energy Catalyst Perlemax and University of Sheffield
Recapitulation S Hot microbubbles can achieve up to 97% efficiency in 30 minutes for a broad range of concentrations – up to 25% greater and in 98% less time than industry S Cold microbubbles yield a MTC 1000 times greater than conventional stripping. 3000 times for hot microbubbles and 15000 times for certain liquors S Adding alkali increased efficiency by up to 105 % BUT… Stripping at pH> 9.0 can be achieved with hot microbubbles S Microbubbles can influence chemical equilibria to generate and strip ammonia
MMARP S Hot microbubble mediated ammonia recovery – in talks with large waste management company S Microbial algal consortia – 1. IIKE award for PoC , NERC award for pilot scale, 2.Grantham Scholar supervision S Tunable salts of Ammonium Carbonate/Carbamate – 50% generation of each salt , 70% conversion per pass for POC. Pilot scale- Energy Catalyst S Working on larger scale implementation of MMARP- ‘Waste Factory’ led by me.
Thanks Any Questions ?
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