Chemical Hydrolysis Technology for organic waste streams TCBB/University of Limerick

Technology Foresight Workshop

23/24th April 2013

J J Leahy 

Can Occupy a Valuable Niche• Employ our chemical expertise to develop abiological processing methods for processing waste wood. (contaminated/hazardous)

• Chemical hydrolysis can be viable at small scales.

• Highly feedstock flexible (no concerns on biota inhibitors, water content, or gasifier performance).

• Acid-catalysed hydrolysis can produced value-added products directly from polysaccharides.

Acid Degradation of Cellulose

Acid Degradation of Hemicellulose

Markets for Products of Acid HydrolysisLevulinic acid, furfural, formic acid, lignin are valuable platform chemicals with huge potential…

Levulinic Acid Derived Chemicals

Chemicals Uses Means of Production

DALA Herbicides, Cosmetics, Diphenolic Acid Resins, Polymers, 

Lubricants, PaintsReaction of LvA with phenol

Succinic Acid (SA) Food additives Oxidation of LvATetrahydrofuran PTMEG production, 

Spandex, SolventCyclisation of SA

Furfural

Chemicals Uses Means of Production

FurfuralFurfuryl alcohol Resins, Hydrogenation of furfural(2,5)‐bis‐hydroxymethyl‐furan (BHMF)

Polyurethane, Polyesters

Formic Acid

Chemicals Uses Means of Production

Formic Acid Silage additive, Leather tanning, Drugs, Dyes, Insecticides

DIBANET process

Existing Processes

•Biofine:• 2-stage dilute acid hydrolysis at high T&P.• Most of the lignocellulse (lignin, condensed sugars) becomes a residue needed for process heat.

• Process not commercialised. Tested mainly on paper.

Dibanet -FP7 Call“Enhancing international cooperation between the EU and Latin America in the field of biofuels”

Levulinic Acid Formic Acid Furfural Solid Residues

Acid Hydrolysis

EsterificationEthanol

Ethyl Levulinate

Fast PyrolysisBio-Oil

BiocharUpgraded Oil

Upgrading

Grinding

Pretreatment

Partner Roles Development of core pretreatment and hydrolysis processes

Analysis of biomass, development of rapid (online) analytical methods

Thermochemical treatment and use of residues

Catalytic conversions of products

Evaluation of process, products and markets

IP Development at UL…A new cost effective process for the acid hydrolysis of lignocellulose waste to Levulinic Acid based on a novel Pretreatment Technology

Overview

• Technical context.• Limiting factors in LA production.• Kinetic model developed and validated.

• Motivation for and development of a novel pretreatment process.

• The pretreatment as the basis of an improved acid hydrolysis process.

• The design.

Processing Capacity

• Lab scale: • 0.1 Lt – 8Lt. • Atm – 50 Bar• In line sampling.

• Pilot scale: • Continuous system. • Up to 1Lt/min throughput.

Cellulose Hemicellulose LigninWheat Straw 38-45 18-25 10-25Rice Straw 35-45 18-25 10-25Newspaper 40-55 25-40 15-30Hardwood 40-55 20-40 18-25Softwood 45-50 25-35 25-35

Lignocellulose Feedstocks for Conversion to Platform Chemicals

• Lignin interference• Hemicellulose and cellulose

optimum conditions distinct• Physical state (Mass transfer)• Reactive intermediates• Optimum between speed/yields• Selectivity highly T dependent• Practicalities:

• T, P [Acid] effect on capital cost

Desired Hydrolysis Reactions Among Many Potential Unwanted Reactions

Originally DIBANET Targeted Improving on Biofine

Results of Kinetic Study

Cellulose Glucose LA + FAHMF

H2O H2O

H2O

TAR

Cellulose Glucose LA + FA

TAR

K1 K2

K3

k1 k2 k3Ao 1.980 x1018 2.529x 1014 1.93 x 1018

Ea 173919 144165 179165m 1.55 1.15 1.28

sec-1

kJ/kmol

Implications of Kinetics for Cellulose Conversion

• Cellulose Hydrolysis • Limiting reaction (high activation energy)

• Temperature • Increase temperature K3 gets faster relative to K2• Decrease yields of LA by increasing temperature

• Glucose concentration in solution is the key• Mass loading can be used to compensate for overall reduced rates at

lower temperature • [H+]

• Increased acid increased rates for all reactions

Existing Processes and PretreatmentsProcess attributes Organosolv/Acetosolv Biofine Milox Steam Explosion

Physical Pre-treatment Yes Yes Yes Yes

Heat Input +++ +++++ +++ +++++

Lignin Fractionation YES NO YES NO

Inherent Pressure Drop No YES NO YES

Holo-Cellulose Hydrolysis Moderate YES NO Moderate

Mineral Acid (H2SO4)

Yes Yes NO Yes/NO

Carrier Ethanol/Acetic acid H2O FA H2O

Objective Lignin recovery LA production Paper pulp Enzymatic feedstock

Ideal Process• Reduce mechanical energy inputs (grinding, chopping).• Fractionate and recover lignin• Increase the rate of cellulose hydrolysis reaction

• Swell/increase Surface Area• Reduce hydrophobicity by removing the lignin

• Operate at the lowest practicable temperature • Operate at the highest practicable acid concentration• Operate at the highest practicable biomass loading • Process the cellulose and hemi-cellulose separately

Oxidative Hydrolysis

• H2O2:• An oxidiser at ambient temperature in combination

with an organic acid yields per-acid: effective lignin dissolution medium.

• Can be catalytically triggered to decompose rapidly (Fe, Transition metals, pH).

• Decomposes exothermically (pressure).• Environmental. • available as a bulk chemical.

Suitability of Pretreated Pulp as a Feedstock for Bioethanol Production

Profile of glucose release during enzymatic digestion of Avicel (microcrystalline cellulose), raw and pretreated Miscanthus (5.0% and 7.5% H2O2) at 45 oC with a commercial cellulase enzyme mix.

Avicel

Raw (non-treated) biomass)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

0 0.45 1.5 7 24 48 72

Glu

cose

rele

ase

(DN

S a

ssay

), 54

0 nm

Duration of the enzymatic hydrolysis (hrs)

Substrate type

Pre-treated biomassFA/H2O2 -(5%)

Pre-treated biomassFA/H2O2 -(7.5%)

•No inhibition of enzyme activityby pre-treated pulp was detected(limiting factor with other pre-treatment)

•FA/H2O2 an effective way ofincreasing the enzymaticdigestibility for conversion intofermentable sugars

0

10

20

30

40

50

60

70

80

1 10 100 1000 10000

Levu

linic

Aci

d Yi

eld

(mol

%)

Time (mins)

Raw Miscanthus, 175C Raw Miscanthus, 150CPretreated 150C

Integrated Design Proposal Basis • Pre-treatment to yield two streams

• Cellulose rich sludge

• FA liquor with dissolved C5 sugars and Lignin

• Liquor is fed to CSTR for conversion of C5 to furfural• [FA] affects conversion

• The mixture is cleaned of humin and silicates

• Various evaporation and water addition steps are used to precipitate the lignin.

• A liquid stream containing FA, Furfural and Water is sent for product recovery and recycling

• Cellulose sent for conventional hydrolysis at 150 C in a series of CSTR’s

Aspen Simulations• Thermodynamics

• Azeotropic systems• FUR/H2O (good literature data)• FA/H2O (good literature data)• EtOH/H2O (good literature data)• OCT/H2O

• NRTL model with HOC adjustment for FA • Developed model for the Liquid-Liquid separation with Octanol

• Unit operation modelling• Distillation columns

• Edmister or Winn-Underwood-Gillian• Pretreatment reactor

• Fortran sub routines

Components and Properties

Mass Balance

Liquid-Liquid Extraction of LA from Aqueous Sulphuric Acid (SA)

• Literature state of the art• LA Loading in recovery stream 0.5-1%• Solvents tested in the absence of strong acid

• Esters (C4-C5)• Ketones (C5-C10)• Alcohols (C5-C10)• Typical KD 1.2-4

• Proposed additives for reactive extraction • quaternary salts, particularly ammonium and phosphonium, TBP, TOP have been

investigated in non acidic medium• In SAAQ the SA will be preferentially taken to the organic phase therefore must

be neutralised beforehand.• Our levulinic acid stream is 7%, therefore process efficiency is increased

without the use of reactive additives. SA available for recycling.

PRET-F INTER

Q-OUT2

Q

INTER2

CELL

Q-OUT1

Q

GAS

LIQ

BIOMS-IN

BIOMS-2

FA-RECYL

FA-IN

FA-1

H2O2-IN

H2O2-1

BIOMS-1

INTER-1

RECOVERY

LIGNIN

7

RECOV-C

SA-FED CELHYD-F

LA-1

RCRY-LA

RSTOIC

PRETRT-1

SEP

PRETRT-2

FLA SH2

PTRTRT-3

BIOMS-ST

FA-STORE

H2O2-ST

BIOMS-FS

SDPPERACD-M

XYL-CON

D

CEL-HYDM HYD-REAC

FL

RCVRY-M

SA-RCYL

Furfural Recovery and FA Recycle

12

14

15

DFUR

B1

10

20B2

4

B3

3

5

B4

7 DFUR2

8

9

Octan-2-ol for LA Recovery

TEST

OCT-FED

LA-SA-EX

LA-OCT2

SA-RCYL

OCT-RCYL

LA

OCT-COL

ETOH-FEDEL-ETOH

EL-CONVETOH-H2O

EL-OUT

EL-DECAN

ETOH-RCY

LA-H2O

ETOH-COL

FLSH-DRY

LA-RCYL

H2O-VAP

Overall Mass BalanceINPUT (MT) OUTPUT (MT)

Waste wood 1.1 Lignin 0.2

H2O2 (50%) 0.2 Furfural (94%) 0.1

Ethanol 0.1 EL (98%) 0.3

OCTANOL 0.002 Formic Acid (82%) 0.1

H2SO4 (98%) 0.002 Tar 0.2

CO2 Offset 1.9

Energy

Kw hr 1540

Cellulose Pulp Hemicellulose + Lignin (Soluble)

Pretreatment

Acid Hydrolysis

Levulinic Acid(258 kg)

Flash

Lignin(180 kg)

Furfural(127 kg)

Formic Acid(102 kg)

No Grinding Required

Residues(90 kg)

Residues(75 kg)

Combustion

Pretreatment Products

DIBANET Products

DownstreamConversion

Heat + Power

Value-Added-Chemicals biofuels

Catalytic Conversion

Bio-Products

(487 kg chemicals + 180 kg lignin)

1 Tonne of waste wood

Proposed Project

Year 1 Year 2 Year 3

Pretreatment + Furfural Production + Recovery

S2: Levulinic Acid ProductionCellulose

biopolymers

Furfural

Lignin

Primary Products

Potential Derivatives