Spent coffee grounds as a versatile source of green energy

Spent Coffee Grounds as a
Versatile Source of Green Energy

Scientific Seminar
Le Ngoc Hoang Anh
th
Hanoi,
Hanoi, 05
05th Octorbor
Octorbor 2020
2020


OUTLINE

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INTRODUCTIO
N
MATERIALS AND
METHODS
RESULTS AND
DISCUSSION

CONCLUSION


INTRODUCTION

However, biodiesel is more
expensive than fossil fuels.

Biodiesel is a good alternative for fossil
fuel.

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INTRODUCTION
Coffee powder
Beverage

Brewed

Coffee powder waste
Extraction with hexane/ether

Triglycerides

Solid waste

Glycerin
Biodiesel

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Ethanol

Fuel pellets

Figure 1. Schematic representation of the biodiesel production process from
spent coffee grounds. The other value-added products such as H2, ethanol,
and fuel pellets can also be achieved from this waste feedstock


MATERIALS AND
METHODS

Oil Extraction

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Transesterification Process

Characterization


MATERIALS AND METHODS
Oil Extraction

Refluxed

Filtered

(Buckner funnel)

Separated
FFAs

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Separated
(rotary evaporator)

characterized & quantified
(HPLC)


MATERIALS AND METHODS
Transesterification
Process

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MATERIALS AND METHODS
Characterization

The yield and composition of the biodiesel were
investigated using HPLC (High performance liquid
chromatography)

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RESULTS AND DISCUSSION

A small amount of FFA,
monoglycerides (MG), and
diglycerides (DG) was also observed
in the oil.

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Figure 2. HPLC chromatogram of the oil extracted from spent coffee grounds
indicating the presence of TG, a small amount of DG, MG, and FFA.


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RESULTS AND DISCUSSION
Source

Advantage

Disadvantage

Tallow, brown
grease, pork fat
(white grease),
lard, fish oil,
poultry fat

Animal fat oxidative stability,

less expensive

High sulfur content, high FFA (50%90%) bad odor, bad cold flow
properties, high cloud point, high pour
point, transportation costs, purification
required

Used
Used vegetable
vegetable
oil
oil

Vegetable
Vegetable oil
oil less
less expensive,
expensive,
readily
available
readily available

Bad
Bad ofor,
ofor, high
high FFA
FFA

Less expensive, higher
Less

expensive,
higher
stability,
well-established
stability,
well-established
transportation,
pleasant
transportation,
pleasant
smell
smell

Extraction of oil from spent coffee
Extraction
of oil from spent coffee
grounds required
grounds required

Coffee oil
Coffee oil

Amount (million
gallons/year)

2.92
2.92

Table 1. Comparison of Coffee Oil with Other Waste Feedstock for Biodiesel Production

The quality of the coffee oil as feedstock for biodiesel production was a better quality and cost-effective
as compared to other waste sources available to date .


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RESULTS AND DISCUSSION

GC-MS analysis showed the presence
of C18-C16 methyl esters of fatty acids,
where more than 99% of the total
composition was methyl esters of palmitic
acid (51.4%), linoleic acid (40.3%), and
stearic acid (8.3%).

Figure 3. GC analysis of the biodiesel shows the different methyl esters of fatty acids present
in the biodiesel produced from the used coffee grounds. The presence of various methyl
esters in coffee biodiesel obtained by MS is shown in the inset table (spectra not shown).


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RESULTS AND DISCUSSION

The analysis of the results shows
that biodiesel obtained from spent
coffee grounds is a strong candidate
as an alternative to diesel.

Table 2. ASTM Results for the Coffee Biodiesel

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RESULTS AND DISCUSSION
 Coffee grounds could still be used as compost
for the garden and/or as fuel pellets.

 A profit of more than $8 million/year, if both
biodiesel and pellets can be marketed.


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CONCLUSION
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≈ 15% of the oil obtained from spent coffee grounds was converted to biodiesel with 100% yield.

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Spent coffee grounds can be used as a potential source to produce quality biodiesel and fuel
pellets, this biodiesel can be used industrially as an alternative to diesel.

Spent coffee ground


THANK YOU!

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ANY QUESTION?