BIOHYDROGEN PRODUCTION OUT OF
WHY HYDROGEN SHOULD BE
Hydrogen is the
simplest and most abundant element in the nature, along with being the lightest
chemical. Hydrogen is colorless, odorless, non-poisonous and 14.4 times lighter
than air. Among all fuels, hydrogen is
the fuel with the most energy per unit mass. (Upper heat value 140.9 MJ / kg,
lower heat value 120.7 MJ / kg) It is an average 1.33 times more efficient fuel
than petroleum fuels. When we compare hydrogen energy to fossil energy sources
the amount of pollutants and greenhouse gases produced are quite low. Today,
most of the hydrogen is obtained from natural gas, and unfortunately natural
gas is also a fossil fuel. Today, about 80% of the world’s energy needs are provided
by fossil fuels, and fossil fuel use causes air pollution, acid rain, global
warming, climate change, ozone layer perforation. The investigations prove that
hydrogen energy provide a more active energy to negate the negative effects of
fossil fuel use. Hydrogen energy is a clean and efficient energy system that
does not contain any polluting gases and harmful chemicals (such as carbon
monoxide or carbon dioxide). However, in order to be used as energy, it has to
be separated from the compounds in the nature. Hydrogen is the most
environmental friendly hydrogen production with the separation of water using
the energy obtained from renewable sources such as wind and sun. Hydrogen
production in the world is basically as;
-48% from natural gas,
-30% from petroleum,
It is produced from water
with -4% electrolysis.
WHAT IS BIOHYDROGEN?
Biohydrogen is a
hydrogen gas (H2) which is produced biologically. This technology
draws interest of scientists
because H2 is a clean fuel, and H2 can be produced by
different kinds of biomass. Biohydrogen is the hydrogen which is produced
biochemically by the help of some microorganisms that
grow without oxygen in dark or light conditions from organic carbon sources
such as cellulose, hemicellulose, sugar or volatile fatty acids.
WHAT IS FERMENTATION AND HOW
IT PRODUCES ENERGY?
Fermentation is the chemical disintegration of a substance through bacteria, fungi, and other microorganisms, usually by heat and foaming. Fermentation is an important biochemical process that provides ATP production by glycolysis under anaerobic conditions, that is, where oxidative phosphorylation is not possible. In fermentation, glucose provides energy production by losing hydrogen individually. As there is no oxygen, the simple organic compounds resulting from this fragmentation are the final electron acceptor and hydrogen acceptor that the cell can use. Even if the last step of fermentation does not produce energy, this process is important for an anaerobic cell because nicotinamide, which is consumed during the conversion of glucose to pyruvate, allows the renewal of adenine dinucleotide (NAD +); This is necessary for the continuation of glycolysis. For example, in alcohol fermentation, the acetaldehyde formed in the vat is converted to ethanol by NADH + H +, which is expelled from the cell. In glycoses fermentation, the most commonly produced simple compound is pyruvate or one or more compounds derived therefrom: ethanol, lactic acid, hydrogen, butyric acid and acetone. While the fermentation of sugars and amino acids can be seen in various organisms, some rare organisms may also ferment alkanoic acids, purines, pyrimidines and other compounds. Various fermentation types are named according to the products they produce. Although fermentation is used in biochemistry for energy-generating reactions in the absence of oxygen, it has a more general meaning in the food industry, including the breakdown reactions of microorganisms in the presence of oxygen (such as vinegar fermentation). This term is used more generally in biotechnology, and any production (including proteins) fermentation done in microorganisms grown in large tanks is called fermentation.
Glycolysis is the sole source of
adenosine triphosphate ATP under anaerobic conditions. Fermentation products
contain chemical energy because they are not completely oxidized. However, in
the absence of oxygen or other highly oxidized electron acceptors, they are no
longer able to metabolize, leaving a residue for the cell. Therefore, ATP
production by fermentation is less efficient than oxidative fermentation, in
which the pyruvate is fully oxidized to carbon dioxide. While two ATP molecules
per glucose are produced in fermentation, this figure is 38 ATP in aerobic
respiration. Although the energy output is low, fermentation provides an
advantage to many organisms as it allows for the lack of oxygen.
The most common ingredient used for fermentation is sugar. Some of
the products obtained from this fermentation are carbon dioxide, ethanol,
lactic acid, and hydrogen gas (H2).
The chemical equation below shows the alcoholic fermentation of
glucose, whose chemical formula is C6H12O6. One
glucose molecule is transformed into two ethanol molecules and two carbon
C6H12O6 ? 2 C2H5OH
+ 2 CO2
C2H5OH is the chemical formula for ethanol.
Before fermentation takes place, one glucose molecule is broken
down into two pyruvate molecules. This is known as glycolysis.
Hydrogen gas production in fermentation
Hydrogen gas is produced in many types of fermentation (mixed acid
fermentation, butyric acid fermentation, caproate fermentation, butanol
fermentation, glyoxylate fermentation), as a way to regenerate NAD+ from NADH.
Electrons are transferred to ferredoxin, which in turn is oxidized by
hydrogenase, producing H2. Hydrogen gas is a substrate for
methanogens and sulfate reducers, which keep the concentration of hydrogen low
and favor the production of such an energy-rich compound, but hydrogen gas at a
fairly high concentration can nevertheless be formed, as in flatus.
As an example of mixed acid fermentation, bacteria such as
Clostridium Pasteurian ferment glucose producing butyrate, acetate, carbon
dioxide and hydrogen gas. The reaction leading to acetate is:
C6H12O6+ 4 H2O ? 2 CH3COO?
+ 2 HCO3? + 4 H+ + 4 H2
Glucose could theoretically be converted into just CO2
and H2, but the global reaction releases little energy.
WHAT IS MOLASSES?
Molasses is a viscous product resulting from refining sugarcane or
sugar beets into sugar. Molasses varies by amount of sugar, method of
extraction, and age of plant. Sugarcane molasses is agreeable in taste and
aroma, and is primarily used for sweetening and flavoring foods in the United
States, Canada, and elsewhere, while sugar beet molasses is foul-smelling and
unpalatable, so it is mainly used as an animal feed additive in Europe and
Russia, where it is chiefly produced. Molasses is a defining component of fine commercial
brown sugar. Some cations
and amino nitrogen compounds inhibit sucrose uptake during fabrication. After
the sucrose is extruded, the remaining liquid is called molasses.
• The carbon source for in situ
remediation of chlorinated hydrocarbons
• Blended with magnesium chloride and
used for de-icing
stock for ethanol fermentation to produce an alternative fuel for motor
• As a brightener in copper
electroforming solution when used in tandem with thiourea
BIOHYDROGEN PRODUCTION OUT OF MOLASSES
Today, consumption of fossil fuels is increasing. Efforts to
destroy the ecosystem, to get rid of foreign dependence in the energy field of
the country and to increase energy diversity have increased the importance of
fuels like bioethanol. Production of bioethanol from sugar beet mulberry as
biomass will lead to the opening of a new market for beet crops, the spreading
of planting seasons, the cultivation of energy agriculture and the increase of
sugar beet cultivation areas. At the same time, bioethanol is also important in
terms of contributing to the diversity of agricultural production, contributing
positively to ecology, establishing a sustainable agricultural structure, and
supporting rural development. Bioethanol is generally obtained by fermentation
from plants containing sugar and starch. Molasses is used in the production of
bioethanol in sugar beet. Melastan bioethanol production; fermentation,
distillation. The alcohol obtained in ethanol production is 96% pure and cannot
be used as fuel alcohol. Ethyl alcohol must be at least 99.5% pure in order to
be able to use it as fuel. For this reason, alcohol plants require purification
and dewatering units after the fermentation unit. Today, due to the decrease of
oil reserves and environmental problems, alternative energy sources such as
bioethanol should be emphasized.
BIOMASS PRODUCTION BY FERMENTATION
Biomass production by fermentation occurs in two ways, photo fermentation and dark fermentation.
The photosynthetic microorganism produces H2 by catalyzing organic acids with nitrogenase in the presence of solar energy. Hydrogen Production with Photo Fermentation The reaction is as follows;C6H12O6 + 6H2O + light energy ? 12H2 + 6CO2
Hydrogen Production with Photosynthetic Bacteria for
-The formation of high theoretical conversion efficiency,The absence of oxygen evolution, which causes the problem of loss of activity in distinct biological systems,- The availability of light in the broad spectrum,- It has advantages such as organic substrates which can derive from the wastewater, and the ability to consume them, to have wastewater treatment potency.
During the production of hydrogen by dark fermentation, anaerobic bacteria produce hydrogen in dark conditions using organic substrates. Because the anaerobic bacteria used do not need the light. Hydrogen Production with Dark Fermentation The reaction is as follows;C6H12O6 + H2O – & 4H2 + 2CO2 + 2CH3COOH
Production of Hydrogen by Dark Fermentation for
– No need for light energy,
– The availability of various carbonaceous wastes as substrates,
-Manufacture of organic acids as a product of the sea, it has the
advantages of not having oxygen restriction problem.
BIOHYDROGEN PRODUCTION OUT OF
The main product obtained from sugar
beet is sugar, and sugar has the ability to ferment easily with microorganism.
20 kg of molasses containing approximately 50% sucrose are obtained from one
ton of sugar beet. After the root sacrose and molasses are obtained, the pulp
is left behind. It represents 22% to 28% dry matter in the sugar beet root,
which is insoluble after extraction of sugar beets and has the ability to
ferment. During the conversion of sugar to ethanol, yeast and some bacteria
play a role in the fermentation of sugars through anaerobic digestion. Almost
half of the world’s ethanol fuel production is produced from sugar plants
(mostly sugar cane) and the remaining half is produced from grains. Sugar
plants can be grown in very large areas of the world. For this reason, it has
some advantages over grains. Sugar beets have another advantage over grains and
other cellulose-containing plants. This is because they need to be fermented
directly and require less time. Sugar cane, sugar beet and sweet sorghum can be
converted into liquid fuel, ethanol, heat and electricity, as potable plants
with potent energy conversion potential.
Situation in the World
6.6 billion liters of ethanol corn (42%), wheat (33%),
sugar beet (18%) and other grains (7%) were produced in EU countries in 2014. A
total of 10.5 million tons of grain and 2.21 million tons of non-quota sugar
beets (white sugar equivalent) were used for ethanol production. These values
??correspond to 8% of sugar beet production with 2% of European cereal
production for 2014. Europe has a very small share in the production of 90.5
million liters of renewable ethanol produced in 2014 in the world. Most of the
ethanol produced is directed towards domestic renewable fuel as internal fuel.
USA (60%) and Brazil (30%) are the countries that produce the most ethanol and
production in the European Union is lower (7%).
The conversion of sugar to ethanol is a simple process
involving only fermentation, but the conversion of corn, wheat, enzymes are
also needed to convert starch to sugar to obtain liquid fuel from cereals.
However, compared to cereals, the storage of sugar beet roots is seen as an
important obstacle in the use of sugar beet as bioethanol raw material. When we
pay attention to the unit area, sugar beet is one of the most efficient sources
for ethanol. It is assumed that 2.44 GJ / t energy can be obtained from sugar
beets (fresh weight), and when this value is converted to ethanol, it is
assumed that 115 l / t ethanol is produced. Considering the average yield (46 t
/ ha of beet, 4.9 t / ha of corn, 2.8 t / ha of wheat) 5.060 l / ha of wheat
was obtained, 952 l / ha of wheat and 1,960 l / ha of alcohol were obtained
from corn. In USA and Europe, irrigation is very high in Mediterranean,
semi-tropical and arid tropical climates where winter beets are grown. Winter
beet cultivation time is 210-300 days, harvested in late summer and late spring
or summer. Ethanol yield from 115 t / ha (fresh weight) of ethanol from 100 t /
ha of pans was 3 times higher than the yield of corn in the US with 11,500 l /
ha of ethanol yield (3751 l / ha from 9.4 t / ha maize yield). ”
produced both in the summer and in the winter are the most preferred places for
biofuel production because in these climate types the beets can be harvested
daily for most of the year. The biomass is dependent on the poten- tial of the
yield, the solar energy taken, and these conditions are advantageous for winter
beet with long vegetation period. When biomass yield is accepted as the most
important parameter for biofuel, higher biomass can be obtained by
hybridization of sugar beet.
How Should Sugar Beet Production
The number of motor vehicles in our country is increasing
day by day and the fuel cost is too high, leading to the production of
alternative energy sources. At the same time, the engines of the vehicles must
be made in such a way that they can use such fuels. Only the dewatering unit
will be added to the alcohol production facilities in the sugar factories and
the bioethanol production will be possible. Sugar beet production to be
processed in accordance with production capacities of sugar factories should be
increased. In addition, winter beet production for bioethanol production should
be considered in addition to the cottage bean grown in our country. However,
beet cultivation areas should be increased. When bioethanol-containing gasoline
is used, the agricultural sector will be supported, the performance of the vehicles
will increase, cheaper fuels and a cleaner and healthier environment will be in
In short, hydrogen energy is superior to other fossil
energy sources in terms of energy efficiency, resource diversity and
environmental impact. For this reason, it should be recognized that increasing
and expanding the use of hydrogen energy by reducing production costs is of primary
importance for the future of our world. According to scientists, the only and
permanent solution to global warming, environmental pollution, image pollution,
acid rain, piercing of the ozone layer, climate change is the use of the
hydrogen energy system. Biological hydrogen production is a good alternative
for the production of hydrogen gas. Biologically, hydrogen production
technologies should be used in production by selecting the most appropriate one
in terms of cost and efficiency according to the existing conditions. Because
the biomass used, the type of enzyme, the type of microorganism, the method to
be selected according to the ambient conditions will be different. For this
reason it is obvious that it is wrong to say that any method is better than
others by comparing methods. In addition, the selection of waste material,
which is also discussed in this article and has a very important share in the
production of biohydrogen, is a factor that directly affects the efficiency.
Therefore, care should be taken in selecting abundant material that is easy to
find, inexpensive, easy to disintegrate during processing, and which will not
create a new contamination while removing pollution. Thus, the production of
biodegradable materials from different waste materials provides both the use of
waste material and the production of clean energy resources.