Solid Acid Catalysts for Waste-to-Biofuels Conversionsindhwakebiocarbon.com/presentations/Lachgar Waste to...Shiba Adhikari, Zach Hood, Marcus Wright and Abdou Lachgar Center for Energy,

Shiba Adhikari, Zach Hood, Marcus Wright and Abdou Lachgar

Center for Energy, Environment, and Sustainability

Department of Chemistry

Solid Acid Catalysts for Waste-to-Biofuels

Conversion

NCEAC/University of Sindh, Jamshoro, Pakistan, Feb. 20-23, 2017

Research Projects in my lab

Molecular Building Block Approach

NSF and WFU

Catalysts for Waste-to-Fuel Conversion

NC Biofuel Center NAS and USAID

Heterogeneous Photocatalysis

Center for Energy,

Environment, and Sustainability

Catalysts for Waste-to-Fuel Conversion

Catalysts for Waste-to-Fuel Conversion

NC Biofuel Center NAS and USAID

Background

Biodiesel production – Industrial process

Research challenges

Functionalized carbon materials

General synthesis approach

Characterization

Catalytic activity

Stability and recyclability

Summary

Outline

Rational

It is all about carbon

Image from Ruddiman, 2001 used by permission of Freeman & Co. http://hyperphysics.phy-astr.gsu.edu/hbase/solar/venusenv.html

Rational

Exponential population growth Too much waste

Use biomass waste to produce solid acid catalysts

catalyst

Convert biomass waste to advanced biofuels

Functionalized Carbon

(Hydrochar and waste-tires)

Waste to fuels conversion?

A small contribution to solving the ‘problem-triangle’

of energy, resources and climate.

What is Hydrochar (HTC)?

• Hydrothermal carbonization is a highly efficient process which

replicates the natural process of coal generation.

• A combination of heat and pressure transforms biowaste into a

carbon dense material with properties similar to biochar.

• In this process, sugars and polysaccharides are converted into

polymers

http://www.antaco.co.uk

History of Hydrochar (HTCs)

• In 1913, Frierich Bergius (Nobel prize laureate 1931 for development of

chemical high-pressure methods) converted biomass to carbon products by

using steam at high pressure.

• In 1932, Berl and Schmidt developed a new method by treating different

biomass samples in the presence of water at temperatures between 150○C

and 350○C.

• In 2006, Markus Antonietti detected its significance for biomass treatment

and reduction of CO2 emission.

Titirici M, (2013), Sustainable Carbon Materials from Hydrothermal Processes.

General process

• Uniform spherical particles

• Functional surfaces (–OH, –COOH, –C(=O)

Funke and Ziegler. Biofuels Bioprod. Biorefin. 2010, 4, 4160-4177

-3H2O

Hydroxymethyl furfural (HMF)

• HTC is an exothermic process that lowers

both the oxygen and hydrogen content.

• Dehydration leading to the formation of

hydroxy methyl furfural (HMF)

Why HTCs?

• Lower emissions compared to biochar

• The only by-product is water.

• Wet process – Biomass can be used without expensive pre-drying

• Accepts numerous biomass types

• HTCs can also be used for soil improvement

• High carbon efficiency

Antonietti et al. Applied Soil Ecology 45 (2010) 238–242

Process Carbon Efficiency

Hydrothermal Carbonization (HTC) 90 %

Alcoholic fermentation 70 %

Anaerobic digestion / biogas 50 %

Other biomass conversion processes 30 %

Composting 10 %

http://www.antaco.co.uk/technology/hydrothermal-carbonisation-htc

What is Biodiesel?

• A diesel fuel replacement produced from vegetable

oils or animal fats waste

• Is made through a conventional chemical process

known as “transesterification.”

• Biodiesel can be used in any diesel

motor in any percent from 0-100% with

no modifications to the engine

http://www.youtube.com/user/NationalBiodiesel#p/a/u/2/RSQ8UwCT4i0

http://www.youtube.com/user/NationalBiodiesel#p/a/6C80F9C60E55E5DA/0/XEovn5Pni20

http://www.youtube.com/watch?v=-oCC6EHCoMU&feature=related

History of biodiesel

• August 10, 1893, Augsburg, Germany, Rudolf Diesel demonstrated a single 10

ft (3 m) iron cylinder that ran on peanut oil.

• Diesel received the Grand Prix at the World Fair in Paris in 1900.

• August 31, 1937, G. Chavanne of the University of Brussels was granted a patent for a

"Procedure for the transformation of vegetable oils for their uses as fuels" (Belgian

Patent 422,877).

http://lipidlibrary.aocs.org/history/Diesel/index.htm

“The use of vegetable oils as engine

fuels may seem insignificant today but

such oils may become, in the course of

time, as important as petroleum and

coal tar products of the present time.” -Rudolph Diesel, 1912

World Biodiesel Production

Sources: IEA and National Board of Biodiesel

• In 2008, about 700 million gallons of

biodiesel were produced, x10 the

70 million gallons produced in 2005.

• Only a tiny fraction of roughly 40

billion gallons of diesel used each

year for on-road transportation.

Emissions

Currently homogeneous alkaline catalysts, namely sodium hydroxide and

potassium hydroxide are commonly used.

Homogeneous acid catalysts are used to lesser extent.

Because

Low catalyst cost and easy availability

Good conversions

Short reaction times at moderate temperatures

Because

Acid catalyzed transestericiation is extremely slow

Requires harsher temperature and pressure conditions

Significantly more effective in esterification of FFA’s

Industrial Process

Bases like KOH and NaOH are commonly used:

Low cost and easy availability

Good conversions and short reaction time

Moderate temperatures (80 oC)

Biodiesel production - Industrial process

https://greenglycerolapplications.wikispaces.com/Transesterification+process+for+biodiesel+production

Base catalyzed transesterification 50 Kg oil + 10 Kg methanol

½ Kg of NaOH

50 Kg biofuel + 5 Kg glyc. + 5 Kg MeOH

Industrial Process

Major Limitations:

High purity feedstock required in case of alkaline catalysts (FFA<0.5 wt%).

Soap formation – hinders fuel-grade biodiesel production. Lower yield

Homogeneous acid catalysts are highly corrosive, require complex

downstream neutralization and separation.

Higher production cost.

Triglyceride Biodiesel Glycerol Methanol

Transesterification reaction

Competing reaction in the presence of base

Desired reaction for

biodiesel production

Oil with high FFA

yields soap rather

than biodiesel.

Base catalyzed transesterification - Problem

Oil source

FFA

Content

Tentative

price

Biodiesel

B100 Price

Refined vegetable oils < 0.05% $ 2.1 /gallon

$ 3.18

/gallon

Crude soybean oil 0.3-0.7% $ 1.7 /gallon

Restaurant waste grease 2-7% 0.97 ¢/gallon

Animal fat 5-30% 0.50 ¢/gallon

Trap grease 75-100% 0.25 ¢/gallon

Food

Waste

What we need is:

A solid catalyst that efficiently converts FFAs to FAME

Requirements for the catalyst:

• Easy to make;

• inexpensive;

• easy to separate;

• easy to dispose of;

• can be regenerated

low quality feedstock

(TG + FFA)

Solid catalyst

TG + FAME

Base Catalysis

FAME

MeOH Esterification

Transesterification

Synthesis of Robust Solid Carbon Catalysts

Different set of carbon-based catalysts have been developed that include low and high

surface area carbons derived from sugars or waste-tires materials.

Their relative stability towards leaching of acid sites and catalytic activity in esterification

of FFA were evaluated.

The two materials demonstrated excellent catalytic activity even after consecutive

exhaustive methanol leaching steps.

a) High surface area HTC carbon prepared from glucose followed by sulfonation

using Cysteine

b) HTC carbon prepared sulfonated waste-tire materials

Deshmane et al. Bioresource Technology, 147, 597–604 (2013).

Functionalized carbons with acid groups

Functionalized carbons with SO3H: suitable for FFA FAME

Functionalization using conc. H2SO4: corrosive, and deactivation

An environmentally friendly method: with better stability.

Carbon

R B N Baig et al, Scientific Reports | 6:39387

Catalysts from Waste-Tire Carbon

Schematic diagram of the conversion of FFA into biodiesel using sulfonated carbon catalysts from waste tires.

Functionalized tire carbon – Synthesis

A K Naskar et al., RSC Adv., 2014, 4, 38213–38221 , https://ornl.gov/sites/default/files/ID_201202980_FS.pdf

The pyrolyzed carbon from tire : developed and

tested for lithium-ion batteries and supercapacitors

(Chemical Sciences Division, ORNL)

The pyrolyzed carbon: functionalization using

cysteine method

STC-cys = Functionalized tire carbon

Sulfonated tire carbon - Characterization

STC-cys = Functionalized tire carbon using L-cysteine method

Physical properties summary table

Surface area decrease during sulfonation:

particle size

Sulfur content increase

A new peak due to SO3H in XPS

Microscopy and XPS

SEM images of:

A) Pyrolyzed waste tire rubber,

B) STC catalyst and,

C) STC-cys catalyst.

TEM images of:

D) Pyrolyzed waste tire rubber,

E) STC catalyst, and

F) STC-cys catalyst.

EDX mapping of sulfur for

pyrolyzed waste tire (H, K), I, L)

STC catalyst (I, L) and STC-cys

catalyst (J, M)

Sulfonated tire carbon - Activity

By varying reaction time

Almost 95 % conversion

after 120 minutes

The conversion of oleic acid (as an example of

FFA) to fatty acid methyl ester (FAME)

FFA FAME

Reaction conditions 1 g of oleic acid

10 molar ex. CH3OH

10 wt % catalyst

Reflux at 80 oC

Catalytic activity Esterification of Oleic acid

• Catalyst loading,

• Methanol to FFA ratio,

• Water effect,

• Mercury poisoning experiment.

65°C

Chemical and Phyical stability

Catalytic activity of:

A) STC catalyst

B) STC-cys catalyst after each Soxhlet

extraction cycle.

XPS spectra of the S2p peak for

C) STC catalyst

D) STC-cys catalyst after each extraction.

Summary and Outlook Accomplishments: • Robust solid acid catalysts have been developed

• These catalysts can be prepared from either waste biomass or waste tire materials

• The catalysts are remarkably effective in conversion of low quality feedstock to

biofuels

• Excellent platform for Science, Technology, Engineering, and Mathematics (STEM)

Education

• Vertical integration of Highschool, Undergraduate, Graduate, postdoctoral training

What needs to be done: • Large scale pilot studies (costly!!)

• Continuous flow studies (in process)

• Mapping the ternary phase diagram (TG/FFA/MeOH)

Acknowledgements

Cynthia Day, Marcus Wright, Wake Forest

University

Zili Wu, Rui Peng, Karren More, Ilia Ivanov Oak

Ridge National Lab (ORNL)

Carrie L. Donley, UNC Chapel Hill

Zachary D. Hood, Vincent Chen, Georgia Institute

of Technology

Thank you

From: http://www.duqlawblogs.org/energy/2015/04/19/biodiesel/

The Standard Biodiesel Cycle

Biodiesel Raw Materials

Oil or Fat Alcohol Catalyst

Soybean Methanol NaOH

Corn Ethanol KOH

Rapeseed

Cottonseed

Sunflower

Beef tallow

Pork Lard

Used cooking oil (yellow grease, etc..)

World Biodiesel Production

Sources: IEA and National Board of Biodiesel

Activity

Ternary phase diagram:

(MeOH/FFA/TG) using 10 wt.% of STC-

cys. For each of these studies, the weight

percent of the STC-cys catalyst is in terms

of the FFA mass and the temperature was

maintained at 80 °C.