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Category Archives: Carbon cycle

The Carbon emission in the atmosphere is steadily increasing.  The latest statistics indicates that it has reached a staggering 35.6 billion tons/yr, a 2.6% increase over the previous year, thanks to the growth of China. It is becoming clear that there is a relationship between the Carbon emission, global warming and erratic weather patterns around the world. According to ‘The Guardian’,

“The chances of the world holding temperature rise to 2C – the level of global warming considered “safe” by scientists – appear to be fading fast with US scientists reporting the second-greatest annual rise in CO2emissions in 2012. Carbon dioxide levels measured at Mauna Loa observatory in Hawaii jumped by 2.67 parts per million (ppm) in 2012 to 395ppm, said Pieter Tans, who leads the greenhouse gas measurement team for the US National Oceanic and Atmospheric Administration (NOAA). The record was an increase of 2.93ppm in 1998.

The jump comes as a study published in Science on Thursday looking at global surface temperatures for the past 1,500 years warned that “recent warming is unprecedented”, prompting UN climate chief, Christiana Figures, to say that “staggering global temps show urgent need to act. Rapid climate change must be countered with accelerated action.” Tans told the Associated Press the major factor was an increase in fossil fuel use. “It’s just a testament to human influence being dominant”, he said. “The prospects of keeping climate change below that [two-degree goal] are fading away.

Preliminary data for February 2013 show CO2 levels last month standing at their highest ever recorded at Manua Loa, a remote volcano in the Pacific. Last month they reached a record 396.80ppm with a jump of 3.26ppm parts per million between February 2012 and 2013. Carbon dioxide levels fluctuate seasonally, with the highest levels usually observed in April. Last year the highest level at Mauna Loa was measured at 396.18ppm. What is disturbing scientists is the acceleration of CO2concentrations in the atmosphere, which are occurring in spite of attempts by governments to restrain fossil fuel emissions. According to the observatory, the average annual rate of increase for the past 10 years has been 2.07ppm – more than double the increase in the 1960s. The average increase in CO2 levels between 1959 to the present was 1.49ppm per year.

The Mauna Loa measurements coincide with a new peer-reviewed study of the pledges made by countries to reduce CO2 emissions. The Dutch government’s scientific advisers show that rich countries will have to reduce emissions by 50% percent below 1990 levels by 2020 if there is to be even a medium chance of limiting warming to 2C, thus preventing some of climate  change‘s worst impacts.”The challenge we already knew was great is even more difficult”, said Kelly Levin, a researcher with the World Resources Institute in Washington. “But even with an increased level of reductions necessary, it shows that a 2° goal is still attainable – if we act ambitiously and immediately.” Extreme weather, which is predicted by climate scientists to occur more frequently as the atmosphere warms and CO2 levels rise, has already been seen widely in 2013. China and India have experienced their coldest winter in decades and Australia has seen a four-month long heat wave with 123 weather records broken during what scientists are calling it ‘angry summer’. “We are in [getting] into new climatic territory. And when you get records being broken at that scale, you can start to see a shifting from one climate system to another. So the climate has in one sense actually changed and we are now entering a new series of climatic conditions that we just haven’t seen before”, said Tim Flannery, head of the Australian government’s climate change commission, this week. Earlier this week the Met Office warned that the “extreme” patterns of flood and drought experienced by Britain in 2012 were likely to become more frequent. One in every five days in 2012 saw flooding but one in four days were in drought”.

The biggest question now is how to put this Carbon genie back into the bottle? renewable energy may be an answer to curtail future Carbon emissions but what about the existing coal-fired power plants that constitutes 60% of the existing power generation in the world? There is no easy solution. But the “Law of conservation of mass” gives us a clue.The Carbon we dig from the earth in the form of coal, combusted into the atmosphere as Carbon dioxide may be captured and recycled back into the system in the form of a fuel.By this way, we may not need fresh coal to be mined.To achive this feat,we need Hydrogen from a renewable source.The renewable Hydrogen can be combined with Carbon dioxide captured from the coal-fired power plants to generate synthetic natural gas (SNG).The SNG generated by this method can be used for future power generation, substituting Coal and future carbon emission can be recycled in the form of SNG. This approach will open up a range of possibilities and potentially cut the carbon emission to zero.Annual CO2 growthAtmospheic Carbon increaseCO2 emissionsGlobal Carbon emissionHydrosol cycleHydrosol thremocycle

Many companies round the world including DOE (Department of energy,Govt of USA) are trying to develop an economically viable method to generate Hydrogen with an estimated cost of poduction at  $ 2.50 /kg of Hydrogen. One potential method is to generate Hydrogen by splitting water using a thermo-chemical process using concentrated solar therml energy developed by European Union called “Hydrosol cycle”. The method by which Hydrogen is generated should be free from any Carbon emision. To clean up  1 Kg Carbon dioxide one will require at least 0.2kg Hydrogen. For example, a 100Mw coal fired power plant emitting about 2256 Mt CO2/day will require about 451 Mt of Hydrogen/day, costing about $1,127,500 per day.It will cost roughly $500/Mt of C02 to  put the ‘ Carbon genie’  back into the bottle! One can imagein the cost of cleaning up  35.6 billion tons of Carbon dioxide  from the atmosphere.Only a Carbon free Hydrogen derived from water can save the world from a potential catastrophe.

We live in a carbon constrained world where carbon emission is considered as the biggest challenge of the twenty-first century. We unearthed fossil fuel which Nature buried for millions of years and burnt them for our advantage to generate power and to run our cars. Scientist pointed out that the unabated emission of greenhouse will cause the globe to warm with dire consequences. However this came as an ‘inconvenient truth’ to industries and Governments around the world. The economic consequences of stopping fossil fuels weighted more than the global warming. Governments were in a precarious situation and unable to take a concrete policy decision. Popular Governments were not willing to risk their power by taking ethical decisions and opted for popular decision to keep up their growth. Then the financial crisis became an issue, which has nothing to do with greenhouse emission or global warming. Yet, the economic and industrial growth stumbled in many developed countries and unemployment skyrocketed. Governments are caught in a situation where they need to take a balanced view between an ethical decision and economic decisison.The overwhelming evidence of global warming and their consequences are slowly felt by countries around the world by natural disasters of various sizes and intensities.

Some scientist suggested that there is nothing wrong using fossil fuels; we can continue with greenhouse emission without risking the economic growth by  capturing  the carbon emission and burying  them underground. Carbon sequestration and clean coal technologies became popular and more funds were allocated to them than renewable energy development.Countires like India and China are not in a hurry to discontinue fossil fuels but continue to make massive investments on coal-fired power plants. They neither tried to capture carbon nor bury them, but continue to emit carbon claiming that it is their turn of economic growth and right to emit carbon emission. The chief of UN panel on climate change headed by an Indian has no sayin the matter.Politicians push scientists into the background when the truth is inconvenient to them.

How feasible in the carbon sequestration technology and what is the cost? Even if we can come up with a successful technology of capturing carbon and burying them underground, there will be a cost involved. This cost will invariably be passed on to the consumer which  will  eventually increase the cost of energy. Constraining carbon emission without incurring a cost can only be a dream. Capturing carbon emission is nothing new; Carbon dioxide is absorbed by solvents like MEA (Monoethanolamine) in many chemical industries. The absorbed carbon dioxide can be stripped free of solvent and the solvent can be recycled. This carbon dioxide can be treated with Ammonia to get Urea, a Fertilizer. But the source of Hydrogen can come only from renewable energy sources. That is why ‘Renewable Hydrogen ‘is the key to solve global warming problem. We can produce Urea from “captured Carbon” and ‘Renewable Hydrogen’ so that we can cut a real quantity of greenhouse emission. Carbon recycling is a sustainable solution than Carbon capturing and burying. Countries like India who depend upon import of Urea for their agriculture production should immediately make Carbon recycling into Urea production mandatory. It is a win situation for everybody in the world.

World is busy developing alternative to Fossil fuel to cut anthropic Greenhouse gas  to avoid global warming. In fact all forms of alternative energy sources except nuclear energy are ‘solar energy’ from the sun, in one form or another. Sun has supplied energy from the time earth was born. It has conducted   ‘photosynthesis’ by supplying light energy and converting atmospheric carbon dioxide and water into glucose for plants, animals and human beings. The excess carbon from the ‘Carbon cycle’ has become fossil fuels under the earth over a time. The fossil fuel is the result of sun’s energy or solar energy. We unearthed fossil fuels and burnt them to extract energy to run our power plants or run our cars. In fact fossil fuel is also a form of  ‘Biofuel’ and technically there is no difference between them except fossil fuel formation takes millions of years.Fossil fuel is nothing but a source of Hydrogen with carbon backbone.

All forms of alternative energy sources we are currently trying to develop such as PV solar, solar concentrators, solar thermal, geothermal energy, wind energy and bioenergy etc, originate from solar energy. The word alternative energy is a misnomer because all these energy are fundamentally solar energy in one form or another.

Solar energy is a radiation of Nuclear fusion  of Hydrogen taking place in the sun. Two Isotopes of Hydrogen called Deuterium (with one proton and one neutron) combine to form a Helium 3 atom and Neutron with release of large energy. Deuterium is non-radioactive and can be extracted from seawater. But this process could not be duplicated commercially for Electricity generation. It is the safest and cleanest form of energy.

In other words, all forms of energy including solar energy come from Hydrogen. That is why Hydrogen has become a potential fuel source in the future. However, developing a commercial technology for the production and usage of hydrogen at a rate cheaper than fossil fuels with zero greenhouse emission has been elusive so far. Generation of Hydrogen from water by Photo electrolysis using a direct sunlight using a Photo catalyst is a promising technology. But duplicating Nature to generate large amount of energy using tiny amount of Hydrogen atom seems to be a distance dream. Nature knows the best. We human beings can use small energy generation technologies such as solar and wind to meet our small energy needs. “There is enough to meets everybody’s need but not everybody’s greed”,Gandhi said.

Exponential growth of population and industries has forced us to look for large power generation and fuel usage at the cost of serious environmental degradation and future generations. Only smarter and cleaner technologies will help sustain the future. Politicians and policy makers  should understand various technologies and their implications than advocating short-sighted and popular energy policies.

We have discussed about the formation of fossil fuel as part of carbon cycle. It takes several million years before the carbon from the plants and animals turn into fossil fuels due to chemical reactions under higher pressure and temperature. The fossil fuels include solid coal, liquid oil and gaseous Hydrocarbons such as crude oil and natural gas. The natural gas forms the top layer due to its lightness. Natural gas is also the result of anaerobic reaction by microorganism in the absence of air converting organic matter under the earth into a gas. The gas during exploration comes with great pressure to be transported across several kilometers. We are actually duplicating this process to generate Biogas from our food and agriculture wastes and other organic matters. The end product is a mixture of methane and carbon dioxide. During oil and gas exploration we get methane and carbon dioxide and other gases such as Hydrogen sulfide depending upon the location of the oil field. That is why Sulfur  and other products such as Mercaptans are present in crude oil and natural gas. When these fossil fuels are burnt the gaseous combustion  products contain sulfur dioxide and oxide of nitrogen along with oxides of carbon.  Air is normally used for combustion which is a mixture of Nitrogen and oxygen in the ration of 71:21,therefore, the combustion products invariably consist of oxides of nitrogen.

We are so addicted to oil and we are even trying to convert  natural gas into oil, similar to gasoline using GTL (gas to oil) process. However all these combustion processes can be reacted with steam to form synthesis gas, a precursor for liquid Hydrocarbon. It is quite obvious that water in the form of steam is a key part in future energy mixes because that is how one can introduce a Hydrogen molecule in the reaction process. Hydrogen in the form of water is the key. Even if we can successfully steam reform natural gas to get Hydrogen we still have problems deal thing with traces of sulfur and Mercaptans, potential poison for  catalyst in PEM (Proton exchange membrane) Fuelcells.The idea  is to generate Hydrogen using a carbonaceous source such as fossil fuel for simple reasons. It is abundantly available but it emits greenhouse gases; but when you introduce Hydrogen into the mix then there is a good possibility of reducing greenhouse emission, even though we still use fossil fuels. Secondly, we are cautious to handle pure Hydrogen due to its explosive nature and the best available option is to mix Hydrogen with combustion products of fossil fuels. The result is the formation of Syngas.

Syngas is an important intermediary that will lead us to the Hydrogen economy of the futue.The syngas can be generated by various methods as long as we have an organic source and water (steam) source. In fact all food and agriculture waste can be converted into syngas either using a biological process or by gasification process. Both will lead to formation of  Methane or syngas.

Syngas is a mixture of hydrogen with carbon dioxide formed in the following sequences, starting with carbon ,air and  steam.

2C + O2——– 2 CO

2CO + 2H2O———2H2 +2 CO2

The carbon source can be any organic source such as coal, coke, wood etc.As you can see in the reaction, the quantity of carbon source is equally important to generate Hydrogen. One can say that Syngas is a match maker between fossil economy of the past and Hydrogen economy of the future. It is a very important chemical reaction that will change the future energy scene in the world.

That is why many counties like US and Australia and in Europe who have much coal deposits are now trying to generate Hydrogen from coal. Once coal is converted into a gas such as syngas then they are one step closer to separate Hydrogen from syngas.Number of companies and research  organizations  around the world are trying to develop  an efficient and economical method of generating Hydrogen from coal. They have to find suitable conditions to generate higher yield of Hydrogen from syngas and then find an efficient system to separate Hydrogen from carbon dioxide. As I have mentioned earlier, the purity of Hydrogen is important especially when we use coal as the basic material because it has number of impurities to be  removed  before converting into a syngas.

As we can see, all energy roads are now leading to Hydrogen as the final clean fuel of the future. When the demand for Hydrogen increase, the demand for water too will   increase because it is the direct source of Hydrogen. Energy and water are two side of the same coin as I have mentioned earlier in the past.

Carbon is the backbone of an organic life on earth. Every life from the smallest microorganism to human beings is made up of carbon. A cycle  called ‘carbon cycle’ that decomposes carbon into carbon dioxide which is used to synthesis Carbohydrates by the  process known as  ‘photosynthesis’ in presence of water and sunlight, as described in the following equation:

6CO2+ 6H2O   + sunlight →  C6H12O6 + 6O2

The oxygen generated during the above process and carbohydrates sustains life of animals and microorganism on earth. These lives consume oxygen and carbohydrates and releases Carbon dioxide by respiration into the atmosphere. The released carbon dioxide breaks down carbohydrates and other organic matters and regenerates carbon dioxide for reuse by animals and other lives. Not all organic matters are decomposed and part of it is stored as carbon biomass in the roots of plants and other organic matters and buried under earth. After millions of years these organic matters turns into fossil fuels under pressure and higher temperature. Carbon is distributed on earth, in water and in atmosphere. Due to increase in population and industrial growth over several decades the carbon dioxide increased gradually in soil, water and atmosphere. Carbon dioxide is also released by natural events like volcanic eruptions.

But the level of carbon dioxide in the atmosphere increased rapidly after industrialisation, when industries unearthed buried fossil fuels and burnt. In fact we are burning carbon at a faster rate than it is regenerated. It is purely man-made and it increases the presence of carbon dioxide both in atmosphere as well as in oceans. The rapid increase of green house emission started 240 years ago when industrial revolution started. The consequences of this unabated greenhouse gases due to combustion has caused ‘global warming’ with many consequences.

As I have mentioned in my previous articles, power generation and transportation are the two major industries that emit bulk of the greenhouse emission. Both industries use age-old technologies of combustion. The world has been complacent about fossil fuels and grossly indifferent to industrial pollution for decades. Global warming is looming as the biggest threat of the twenty-first century, yet we are not acting. Politicians deny global warming and they want to carry on the business as usual, at the peril of the future generations.

Powerful countries like US, China and India are reluctant to pass a unanimous resolution to set target for carbon emission, while smaller nations remain as powerless onlookers. These powerful nations can drag the rest of the world with them to face the wrath of the Mother Nature with disastrous consequences for their inaction.

It is quite obvious that world have no choice but switch to cleaner energy sources and leave the fossil fuels buried deep under the earth. A new paradigm shift in the way we generate energy and use them is the key for the survival of mankind. We need to develop Hydrogen as an alternative fuel source and Government should encourage innovations in such technologies, while they simultaneously price carbon. In the absence of a concrete legislation and mechanism to penalize polluters, industries will continue to use fossil fuels. A simple cost benefit analysis will show that taxing on polluters and simultaneously introducing renewable technologies will benefit the world in the long run.

 

 

 

 

 

 

 

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