S

Hot Microbubble Injection in Thin Liquid Layers for Ammonia –

Water Separations

Pratik Desai AMIChemE AMInstP GradEI

Professor William B 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 Smaller the bubble, > is the energy required!

Fluidic Oscillator No-moving part bi-stable diverter valve – Several benefits

Fluidic Oscillation Reduces Bubble Size

Steady Flow Bubble Formation

Oscillatory Bubble Formation

Block Diagram

Hypothesis - Basis

Temperature gradient (Ethanol-Water)

Concentration gradient (Ammonia-Water)

Leachate is complex & difficult to analyse quickly for rapid 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

FC PC

TI

FI

TI

AIR INLET

FLUIDIC OSCILLATOR

DIFFUSER

BLEED VALVES

ELECTRIC HEATER

MICROBUBBLE GENERATION (HXRig)

TI

TI

TC

TI

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 – 100 mμ

S Low pressure drop- 20 mbar – Calculations from Holdich et al ,2006 – maintained by larger orifice – 100-150 m , greater porosity & thinner sparger μ

S Proud centre, thin at sides for even flow distribution due to low pressure drop

S Thermal inertance to be kept low for maximal heat transfer to bubble

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!

3000 times for hot microbubbles!

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)

Cheung et al. (1997)

Cheung et al. (1997)

Kabdasli et al. (2000) Marttinen et al. (2002)

Marttinen et al. (2002)

Silva et al. (2004)

Collivignarelli et al. (1998)

0

20

40

60

80

100

0.1 1 10 100 1000

Str

ipp

ing

eff

icie

nc

y (%

)

Processing time (h)

Stripping

Adsorption

Chemical precipitation

Oxidation

Latest modifications

15,000 times for some ammonia rich liquors!

MMARP – Waste Factory

Pratik D Desai

Professor William B J Zimmerman

Microbubble Mediated Ammonia Recovery Processes

Desai-Zimmerman MMARP

LeachateAmmonia Removal, COD/BOD Reduction,Heavy Metal Ion Densi ication and Increasein Optical Transparency

Removal of Heavy MetalIons & Need for BOD/COD, Lipid Production

Micro lotationSeparation of MAC &Recovery of Metals,

Sewering the remnant off.

Flue Gas enriched using FO mineral carbonation/ Ammonia

Mb Intervention 1 – Preprocessing

Mb Intervention 2 – Increased Growth Rate Mb Intervention 4 –

Algal flotation and separation

Ammonia converted to other products – 1. Pall Knorr Synthesis - Grantham Scholar co-supervised by WBJZ and PD – High Value product 2. Conversion to Tuneable salts- IIKE2 Scale up – Energy Cat 3. Used as fertilizer via microbubble condenser (Project running) 4. Upgraded via plasma microreactor(depends on today) 5. Used as a source for MAC growth by in situ urea conversion – Patent pending – work proceeding from IIKE 1 and IIKE 2

Mb Intervention 3 – Microbubble condenser

Lipid rich MACs to be used for energy recovery

Biomass used for AD – Energy plus CHP – Energy Catalyst

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.

+ NH3 (aq )

Optimise to select for mono- di- tri-ethanolamines

Scheme 2

O H2NOH

HNOH

2N

OH3

OHO + NH3 (aq ) HO NH2

OH High value chiral

intermediates

R1

OR2

O+ NH3 (aq ) N

HR2R1

Stable aromatic products

Relatively poor aqueous solubilityScheme 1

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 CatalystPerlemax 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

S Entire factory generated from waste making each step viable and fiscally sustainable

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 ?