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Showing posts with label Carbon recycling. Show all posts
Showing posts with label Carbon recycling. Show all posts

Wednesday, November 18, 2020

Can CCS and CCUS lead us to achieve Net Zero emission by 2050?

 CCS (carbon capture and sequestration) and CCUS (Carbon capture, utilization, and storage) technologies are essentially “after thought” to fix the CO2 emission by 2050. It also indirectly encourages continuity of fossil fuel usage for a foreseeable future to help those industries who have invested billions of dollars in creating their infrastructures such as “fracking”. Fracking generates hundreds of cubic meters of toxic effluent whose salinity is more than ten times that of the salinity of seawater.  It is an environmental nightmare. Are these technologies practicable? Will they pay $100 or more for a ton of CO2 to capture and then transport hundreds of kms distance to find a suitable site; and even if they pay what will be the cost implications? Certainly, their cost of production will sharply increase, which will be necessarily passed on to the consumers whether it is a power industry or oil and gas industry. Why some of the CCS projects are dormant in many parts of the world? They claim injecting CO2 into existing oil field will increase oil production. Is there an evidence to substantiate such claims? But how many such oil fields exist in Australia, for example? The same question should be raised for all the countries around the world especially those oil importing countries like India, for example.  IEA should publish necessary data to back up they claim that CCS and CCUS will lead to zero emission by 2050. In the absence of such data and hard evidence and the cost and economic analysis these projects will lead us nowhere? Without imposing Carbon tax as a financial incentive (not as a penalty) will these industries embark upon such a venture? The Carbon tax cannot be less than $250/Mt (because Carbon capture from air, for example, cost more than $150 to 200/Mt depending upon the maturity of technology). Now they want to utilize capture Carbon to produce synthetic fuel with green Hydrogen. Green hydrogen is awfully expensive, renewable energy is costly and storing them is prohibitively costly and converting them to Hydrogen by electrolysis is even more expensive. Despite all these expensive measures can zero emission be achieved by 2050. The cost of green fuel will be 10 times more than fossil fuels currently used. Will consumers afford to pay for such high fuel cos? Many questions remain unanswered. The word “Carbon capture” implies continuity of fossil fuel. It is like tobacco industry. At least in cigarette packs there is a warning ” smoking is injuries to health” but there is no such warnings in CCS or CCUS because the “captured CO2 will be released into atmosphere slowly at the point of usage in the near future , for example, Urea made out of captured CO2 will slowly release CO2 back into atmosphere by soli enzymes. Conversion to “concrete” or “nano Carbon” are claimed to be potential products but only future can tell. We are talking about “billions of tons of CO2”. Only carbon recycling and circular economy will be the answer and not CCS or CCUS.

Wednesday, June 29, 2016

Carbon is to return to Carbon

Carbon emission is a matter of great concern to all the countries around the world due to the global warming and climate change. After the Paris talks many countries are genuinely trying to reduce their emissions either by switching over to renewable energy or cutting down their emissions by reducing their Carbon footprint. In their desperate measure to reduce Carbon emissions some countries like Canada are trying to accelerate carbon emission reduction by promoting innovation technologies with millions of dollars of grant money. Recent fires in the state of Alberta, rich in oil sand deposits have opened the eyes of the world to witness how a disaster can unfold so quickly and thousands of people to be evacuated in a short notice. Many fled their homes leaving behind their valuables and memories. It was one of the worst fire disasters in recent memory. Canada especially the state of Alberta is now all the more determined to avert such incidents in the future but also equally determined to reduce their Carbon emissions. The fire is due to dry conditions due to global warming and accelerated by oil sands. It is a perfect recipe for a disaster. Many countries have switched over from coal to natural gas as a cleaner fuel to reduce their Carbon emission. Natural gas emits less CO2 compared to coal. But does it help combat global warming? One has to compare the two different fuels and their combustion by the following reactions: C + O2 ----> CO2 and CH4 + 2O2 -------> CO2 + 2H2O Combustion of coal requires less Oxygen (air) when compared to combustion of natural gas which requires twice the volume of Oxygen (air). Coal combustion emits oxides of Nitrogen and Sulphur apart from CO2 and a minor quantity of water vapour and particulate matters. Combustion of natural gas releases twice the volume of water vapour apart from oxides of Nitrogen and sulphur. Recent findings by NASA confirms that water vapour is the major greenhouse gas apart from CO2 that is responsible for warming globe and the climate change. Therefore, natural gas does not help combating global warming and climate change. The following excerpts from NASA highlights this fact: Water Vapour Confirmed as Major Player in Climate Change Credit: NASA The distribution of atmospheric water vapour, a significant greenhouse gas, varies across the globe. During the summer and fall of 2005, this visualization shows that most vapour collects at tropical latitudes, particularly over south Asia, where monsoon thunderstorms swept the gas some 2 miles above the land. Water vapour is known to be Earth’s most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change. Andrew Dressler and colleagues from Texas A&M University in College Station confirmed that the heat-amplifying effect of water vapour is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere. With new observations, the scientists confirmed experimentally what existing climate models had anticipated theoretically. The research team used novel data from the Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite to measure precisely the humidity throughout the lowest 10 miles of the atmosphere. That information was combined with global observations of shifts in temperature, allowing researchers to build a comprehensive picture of the interplay between water vapour, carbon dioxide, and other atmosphere-warming gases. The NASA-funded research was published recently in the American Geophysical Union's Geophysical Research Letters. AIRS is the first instrument to distinguish differences in the amount of water vapour at all altitudes within the troposphere. Using data from AIRS, the team observed how atmospheric water vapour reacted to shifts in surface temperatures between 2003 and 2008. By determining how humidity changed with surface temperature, the team could compute the average global strength of the water vapour feedback. “This new data set shows that as surface temperature increases, so does atmospheric humidity,” Dressler said. “Dumping greenhouse gases into the atmosphere makes the atmosphere more humid. And since water vapour is itself a greenhouse gas, the increase in humidity amplifies the warming from carbon dioxide." Specifically, the team found that if Earth warms 1.8 degrees Fahrenheit, the associated increase in water vapour will trap an extra 2 Watts of energy per square meter (about 11
square feet) "That number may not sound like much, but add up all of that energy over the entire Earth surface and you find that water vapour is trapping a lot of energy," Dressler said. "We now think the water vapour feedback is extraordinarily strong, capable of doubling the warming due to carbon dioxide alone." Because the new precise observations agree with existing assessments of water vapour’s impact, researchers are more confident than ever in model predictions that Earth's leading greenhouse gas will contribute to a temperature rise of a few degrees by the end of the century. The amount water vapour released by burning natural gas is twice the volume of natural gas burnt. A plant using 10,000 m3/day natural gas can release 20,000m3/day water vapour that can be recovered. In fact, if the Gulf countries can recover water from exhaust of their gas fired power plants they may not require any water by desalination of seawater at all. Current consumption of natural gas world-wide exceeds 3.5 trillion cubic meters which roughly translates to 7 trillion cubic meters of water vapour into the atmosphere. Such a large volume has a potential to change our climate system.What goes up as water vapour has to condense into water and come down.It has a potential to flood many parts of the world and we are already witnessing flash flooding more frequently.The economic loss by such natural disasters may run into several hundreds of billion dollars in future.It is absoluetly critical that human induced emissions are curtailed with great urgency. It is interesting to examine how the state of Alberta is trying to reduce their carbon emissions by promoting innovative technologies. Majority of the proposals are supposed to convert CO2 emissions into “a useful product” so that the emission can be curtailed or reduced. A quick glance on the list of the proposals they have funded so far indicates they will convert CO2 into an industrial chemical such as Methanol or a Fertilizer such as Urea or alkaline chemicals such as bicarbonates and calcium carbonates etc. Can they really solve the problem of carbon emissions by turning them into useful products? The answer is most likely no. It will help capture CO2 at Alberta but it will be released somewhere else where the end products are used. It will simply shift the problems of Carbon emission from Alberta into some other region of the world. For example, Urea synthesised from captured CO2 will again be released into the atmosphere when Urea is used by farmers. An enzyme in the soil will release the CO2 from Urea into the atmosphere. The only real solution is to convert captured CO2 back into a fuel such as SNG (synthetic natural gas) so that it can be recycled into the power plant. By this way the CO2 emission will be converted into solid Carbon. One need not bury CO2 under the ground or emit it into the atmosphere but constantly recycle into SNG so that power plant can generate power continuously without emitting any greenhouse emissions. To do this we need Hydrogen. At present Hydrogen is produced commercially from natural gas but with carbon emission. Other methods of producing Hydrogen without carbon emissions are expensive. But Hydrogen can be generated from natural gas without Carbon emission and it can be used to convert captured CO2 from power plants into SNG. In other words, two greenhouse gases namely CO2 and methane (CH4) will be reacted to generate commercially valuable Carbon nanotube as a main product as shown below. This high temperature reaction can generate superheated steam that can generate power while a valuable solid Carbon is regenerated. Such a process is still in a developmental stage but has a potential to become a commercial reality in the near future. CH4 + CO2 ------------> 2C + 2 H2O In fact, the carbon emission is converted back into a solid Carbon. The Carbon is to return to Carbon to avoid GHG emission (CO2, N2O, NO2 and H2O) that is changing our climate.

Thursday, July 11, 2013

How to control Carbon emissions in coal-fired power plants?

“Over two-thirds of today’s proven reserves of fossil fuels need to still be in the ground in 2050 in order to prevent catastrophic levels of climate change” – a warning by scientists. There is a great deal of debate on climate change due to man-made Carbon emissions and how to control it without any further escalation. The first obvious option will be to completely stop the usage of fossil fuel with immediate effect. But it is practically not feasible unless there is an alternative Non-Carbon fuel readily available to substitute fossil fuels. The second option will be to capture carbon emission and bury them under ground by CCS (Carbon capture and sequestration) method. But this concept is still not proven commercially and there are still currently many uncertainties with this technology, the cost involved and environmental implications etc.The third option will be not to use fresh fossil fuel for combustion or capture and bury the Carbon emissions but convert the Carbon emissions into a synthetic hydrocarbon fuel such as synthetic natural gas (SNG) and recycle them. By this way the level of existing Carbon emission can be maintained at current levels without any further escalation. At least the Carbon emission levels can be reduced substantially and maintained at lower levels to mitigate climate changes. It is technically feasible to implement the third option but it has to be implemented with great urgency. One way of converting Carbon emission is to capture and purify them using conventional methods and then react with Hydrogen to produce synthetic natural gas (SNG) CO2 + 4 H2 ----------> CH4 + 2 H2O The same process will be used by NASA to eliminate carbon built-up in the flights by crew members during their long voyage into the space and also to survive in places like Mars where the atmosphere is predominantly carbon dioxide. But we need Hydrogen which is renewable so that the above process can be sustained in the future .Currently the cost of Hydrogen production using renewal energy sources are expensive due to high initial investment and the large energy consumption. We have now developed a new process to generate syngas using simple coal, which is predominantly Hydrogen to be used as a Carbon sink to convert Carbon emissions into synthetic natural gas (SNG). The same Hydrogen rich syngas can be directly used to generate power using gas turbine in a simple or combined cycle mode. The Carbon emission from the gas turbine can be converted into SNG (synthetic natural gas) using surplus Hydrogen-rich syngas. The SNG thus produced can be distributed for CHP (combined heat and power) applications so that the Carbon emission can be controlled or distributed. By implementing the above process one should be able to maintain Carbon at specific level in the atmosphere. Existing coal fired power plants can retrofit this technology so that they will be able to reduce their Carbon emissions substantially; they can also produce SNG as a by-product using their Carbon emissions and achieve zero Carbon emission at their site while generating revenue by sale of SNG. Coal is the cheapest and widely used fossil fuel for power generation all over the world. Therefore it will be a win situation for everyone to use coal and also to reduce Carbon emissions that can address the problems of climate change. Meanwhile research is going on to generate renewable Hydrogen cheaply directly from water using various technologies. But we believe we are still far away from achieving this goal and we require immediate solution to address our climate change problems. Recently BASF made a press release‎ claiming a break-through technology to generate Hydrogen from natural gas without any CO2 emissions.

Saturday, April 21, 2012

Carbon capture or Carbon recycle?

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. Scientists pointed out that the unabated emission of greenhouse will cause the globe to warm with dire consequences.This came as an ‘inconvenient truth’ to industries and Governments around the world. However, economic consequences of stopping fossil fuels outweiged the impact of global warming. Governments were in a precarious situation and were 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 maintain 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 scientists suggested that there was nothing wrong using fossil fuels; we could continue with greenhouse emission without risking the economic growth by capturing the carbon 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 were not in a hurry to discontinue fossil fuels but continued to make massive investments on coal fired power plants. They neither try 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 say in the matter.Politicians push scientists into the background whenever 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 reduce a substantial 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.