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Showing posts with label Hydrogen economy. Show all posts
Showing posts with label Hydrogen economy. Show all posts

Friday, March 21, 2014

It is time to switch over from Carbon to Hydrocarbon


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 to SNG from coal will reduce 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 reduce 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 reduce 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 reduce 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 currently 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 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 reduce 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. President Obama's recent announcement of Carbon reduction plan by coal-fired power plants in USA is a bold step in the right direction.A more ambitious plan may be required to avoid catastrophic climate change that might cost billions of dollar in health related issues and on rebuilding damaged infrastructure. 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.

Tuesday, March 13, 2012

Coal-water-slurry- a new source of Hydrogen?

Dirty coal is still a popular choice for power generation around the world, irrespective of the status of the country, whether industrially advanced or backward. The abundant availability and cheap cost, makes coal more attractive from investor’s point of view; they care less for the environment, while Governments turn a blind eye to all the emissions and pollutions. It is a question of survival for millions of people who work in coal mines and industries. It is one of the toughest challenges many Governments are facing. Take for example India; about 65% of power generation still comes from coal. The import of coal increases year after year and there is no immediate solution in sight. Indian coal is a low grade coal with very high ash content. Each coal-fired power plant generates huge amount of fly ash and they stockpile them; supposed to be used in the production of Portland cement. It is a big business. China and Indonesia too uses coal as a major fuel for power generation. But they have come out with an innovative and pragmatic method of using coal. They use coal-water-slurry (CWS), a finely pulverized high grade coal (calorific value 5100-6100Kcal/kg) in water. They use some chemical additives that make the slurry a homogeneous fluid, similar to a Hydrocarbon such as Heavy fuel oil (HFO).The advantage with CWS is it can be easily pumped and injected into a furnace or boiler using ceramic nozzles, obviously to avoid erosion due the abrasive nature of coal, just like firing diesel or heavy oil. According to the literature, 1.8 -2.2 tons of CWS is equivalent to 1 ton of Heavy fuel oil (HFO) and it costs the same. It cost only US$ 62 million to retrofit an existing coal fired power plant with CWS system and the yearly savings are estimated at US$ 41 mil per year, an attractive rerun on investment. The beautiful aspect of this method is it generates Hydrogen rich Syngas according to the following chemical reaction. 2C + O2+2 H2O -------- 2H2+2 CO2, when the mixture is subject to gasification instead of mere combustion. The combustion efficiency is about 96-99% and the boiler efficiency of more than 90%. It generates less Sulfur dioxide and Nitrogen oxide emissions and good for the environment compared to conventional coal- fired power plants. It is a good technology that needs the attention of Governments especially India, China and Indonesisa.Even coal rich countries like US, Australia should focus on this technology apart from their persuasion such as carbon sequestration. In fact, this will open up new avenues for India and China to switch over to Hydrogen economy, without making substantial investments. The coal-water-slurry fluid has a property similar to a Hydrocarbon as shown below. Density 65-70% ,Viscosity 1000Cp, Size d< 50 microns, Ash content <7, Sulfur<0.5%. It is easier to handle a liquid than solid coal. Pulverised coal is pneumatically conveyed and fired in rotary cement kilns for so many years. There is nothing new about it. Similarly coal water slurry can be a game changer for the power industry if it is combined with Gasification and combined cycle. It will lead into Hydrogen based power generation industries using Fuel cell such as Molten Carbonate Fuel cell (MCFC). I believe there is a clear opportunity for the Governments and private industries to seriously look into CWS technology which I believe, is a ‘precursor’ for Hydrogen economy of the future.