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Category Archives: Greenhouse gas emission

There is likely to be a dramatic change in energy landscape with introduction of super critical CO2 power cycle. It not only increases the power efficiency, reduces the foot print considerably, utilizes part of CO2 emission internally in the form of super critical fluid and open a new path to eliminate Carbon emission completely (zero Carbon emission). It also reduces the water consumption in power generation unlike current conventional Rankine cycle power plants. We will soon be able to continue to generate base load power using fossil fuels with zero carbon emission. Unlike Carbon capture and sequestration already tried unsuccessfully in many parts of the world, Carbon capture and recycle will open a new chapter in the history of power generation. By capturing carbon in a solid form with potential industrial applications such a possibility is now within our reach. It means utilization of existing fossil fuel based power generation infrastructure without any Carbon emission and continue to generate continuous power to meet the increasing demand at a reasonable cost. The current focus on renewable energy will continue but until a practical and viable energy and mature storage technology is developed the renewable energy will have uncertainties. Whatever may be the case the overall cost of energy is likely to go up.

Introduction of Oxy combustion in natural gas turbine has eliminated the oxides of Nitrogen from flue gas thus facilitating separation of CO2 from water and recycling water vapour into combustion process. The condensate from gas turbine is a by-product. Despite the usage of CO2 in the form of super critical fluid there is still an excess CO2 to be disposed of.

A conceptual design to capture CO2 and convert them into SNG while generating additional power using the superheated steam obtained as a by-product of methanation has created a new opportunity to achieve zero carbon emission.

It is an exciting development and our company is now in an advanced stage of developing and commercializing such a technology.

Our new reformation process of natural gas using the captured CO2 and steam allows to precipitate Carbon in a solid form. The chemistry of the process can be explained by the following final methanation process using a proprietary catalyst involving few steps.oxy-fuel-directly-heated-sco2-power-cycle-flow-diagram-1sco2-power-cycle

3CH4 +CO2 +H2O ——–> 2CH4 + 3 H2O + 2 C which will take a final form as follows:

CH4 + CO2 ——> 2H2O + 2C

The superheated steam generated in the process can be exported to generate additional power while the condensate water can be exported and recycled. By using an excess of natural gas the captured CO2 is converted into SNG (synthetic natural gas) which can be recycled into the gas turbine thus achieving a zero-carbon emission while continuing to generate base load power. Such a technology can easily be integrated with other sources of energy such as solar, biomass, waste heat and nuclear.

 

 

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When Carbon emission is high and the globe is warming due to such emissions then the simple and immediate solution to address this issue is to convert Carbon into Hydrocarbon, and the simplest Hydrocarbon is Methane (CH4).By simply introducing Hydrogen atom into Carbon atom the entire fuel property changes. For example the heating value of coal is only 5000-6500 kcal/kg at the maximum while the heating value of Methane (natural gas) increases to 9500 kcal/m3 by the above conversion. It means the same power generated by coal can be generated by using almost half the quantity of natural gas. Converting Carbon into substituted natural gas (SNG) is one way of addressing climate change in a short span of time. By switching over the SNG from coal will cut the CO2 emission almost by 50%.

Global warming due to GHG emission has become a serious environmental issue in recent times and more and more investments are made on renewable energy projects such as solar and wind etc. In spite of the major thrust on renewable energy projects the main source of power is still generated around the world  using fossil fuel especially Coal  due to its abundance and low-cost. Moreover the investment already made on fossil fuel infrastructures are too big to be ignored and investment required to substitute coal-fired power plants by renewable energy are too large and gestation periods are too long to maintain the current electricity demand and to meet the future demands. The cost of renewable energy also is high and there is great resistance by consumers to switch over to renewable energy. Many Governments are reluctant to subsidize renewable energy due to their financial constraints. That is why countries like China which is growing at the rate of more than 8% pa are trying to decrease the ‘Carbon intensity’ rather than closing down the coal–fired power plants by setting up SNG (synthetic natural gas) plants by gasification of  coal . This will cut their Carbon emissions almost by 50% surpassing all other countries around the world in short span of time, thus meeting their emission targets agreed in “Kyoto protocol”. They can also meet the increasing electricity demand by using “syngas” generated by coal gasification plants, while reducing the Carbon pollution. They will also be able to produce Diesel and Gasoline from coal similar to the “SESOL” plant in South Africa which is already operating successfully for the past 50 years.

“Leveraging Natural Gas to Reduce Greenhouse Gas Emissions” – a summary report by Center for Energy and Climate Solutions (C2ES) have highlighted the following in their report.

“Recent technological advances have unleashed a boom in U.S. natural gas production, with expanded supplies and substantially lower prices projected well into the future. Because combusting natural gas yields fewer greenhouse gas emissions than coal or petroleum, the expanded use of natural gas offers significant opportunities to help address global climate change.

The substitution of gas for coal in the power sector, for example, has contributed to a recent decline in U.S. greenhouse gas emissions. Natural gas, however, is not carbon-free. Apart from the emissions released by its combustion, natural gas is composed primarily of methane (CH4), a potent greenhouse gas, and the direct release of methane during production, transmission, and distribution may offset some of the potential climate benefits of its expanded use across the economy.

This report explores the opportunities and challenges in leveraging the natural gas boom to achieve further reductions in U.S. greenhouse gas emissions. Examining the implications of expanded use in key sectors of the economy, it recommends policies and actions needed to maximize climate benefits of natural gas use in power generation, buildings, manufacturing, and transportation. More broadly, the report draws the following conclusions:

•The expanded use of natural gas—as a replacement for coal and petroleum—can help our  efforts to cut greenhouse gas emissions in the near to mid-term, even as the economy grows. In 2013, energy sector emissions are at the lowest levels since 1994, in part because of the substitution of natural gas for other fossil fuels, particularly coal. Total U.S. emissions are not expected to reach 2005 levels again until sometime after 2040.

• Substitution of natural gas for other fossil fuels cannot be the sole basis for long-term U.S. efforts to address climate change because natural gas is a fossil fuel and its combustion emits greenhouse gases. To avoid dangerous climate change, greater reductions will be necessary than natural gas alone can provide. Ensuring that low-carbon investment dramatically expands must be a priority. Zero-emission sources of energy, such as wind, nuclear and solar, are critical, as are the use of carbon capture-and-storage technologies at fossil fuel plants and continued improvements in energy efficiency.

• Along with substituting natural gas for other fossil fuels, direct releases of methane into the atmosphere must be minimized. It is important to better understand and more accurately measure the greenhouse gas emissions from natural gas production and use in order to achieve emissions reductions along the entire natural gas value chain.”

Countries like India should emulate the Chinese model and become self-sufficient in meeting their growing energy demand without relying completely on imported Petroleum products. Import of petroleum products is the single largest foreign exchange drain for India, restricting their economic growth to less than 5%. Countries that rely completely on coal-fired power plants can set up coal hydro-gasification and gasification plants to cut their Carbon emissions in the immediate future while setting up renewable energy projects as a long-term solution.

Transiting Carbon economy into Hydrogen economy is a bumpy road and it will not be  easy to achieve in a short span of time. The logical path for such transition will be to switch coal based power generation into gas based power generation for the following reasons.

The largest Carbon emissions are from power generation and transportation. Transportation industry is already going through a transition from fossil fuel to Hydrogen. More future cars will be based either on Fuel cell or Electric and in both cases the fuel is the critical issue. Battery technology also will be an issue for Electric cars. It is more practical to generate Hydrogen from natural gas and to set up Hydrogen fuel stations than generating Hydrogen from solar-powered water electrolysis. With improvement on Fuel cell technology it is more likely that PEM Fuel cell may be able to operate on Hydrogen derived from natural gas that is completely free from any Sulphur compounds. Even for Electric cars, natural gas will play an important role as a fuel for power generation and distribution in the near future as we transit from Carbon economy to  full-fledged Hydrogen economy.

Countries like India with highest economic growth will have to be pragmatic by setting up more SNG plants with indigenous coal than depending on imported LNG. India has only two LNG terminals now in operation but do not have gas transmission infrastructure. With increasing demand for natural gas from all over the world and lack of LNG receiving terminals, India will have to face a serious fuel and power shortage in the future. By installing more coal gasification and SNG plants with down-stream products like Diesel and petrol, India can overcome the fuel and power shortage. In fact India set up the first coal gasification and Ammonia and Urea plant in Neyveli (Neyveli Lignite Corporation) way back in Fifties after her independence and it is time to visit the past.

Renewable energy is certainly the long-term solution for energy demand but we have to consider the amount of GHG emission associated with production PV solar panels, wind turbines and batteries. There is no easy fix to cut GHG emission in short span of time but switching Carbon to hydrocarbon will certainly reduce the emissions scientists are advocating and water (steam) is the key to introduce such Hydrogen atom into the Carbon atom. That is why we always believe “Water and Energy are two sides of the same coin” and renewable Hydrogen will be the key to our future energy.

For more information on the above topic please refer to the following link:

Source: Harvard University

Link: Coal to Natural gas Fuel switching and Carbon dioxide (CO2) emission reduction.

Date: Apr 2011.

Author: Jackson Salovaara.

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