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Category Archives: Hydrogen based Gas turine

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 Government 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 a 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 equal to 1 ton of Heavy fuel oil (HFO) and it costs about 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 new avenues for India and China to switch over to Hydrogen economy without making large 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 easy to handle a liquid than solid coal. pulverized 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 industry 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.

Renewable Hydrogen is the key that can offer us energy independence in the twenty-first century. Fossil fuel usage will still continue for some more time because the world has already invested massively on fossil fuel infrastructures. The stacks are too high for them to switch over to renewable over night. It is the Mother Nature who provided us coal, oil and gas all these years using her manufacturing process under the earth over millions of years. But we human beings exceeded her tolerance limit by emitting greenhouse emission by our rapid growth in population and industrialisation.We failed to discover an alternate fuel in time and continued with an age-old technology with all its inefficiencies. Inefficiencies breed pollution. We were keen to use the heat of combustion by burning a fossil fuel to generate electricity or drive our cars, but paid no attention to the gases released during such combustion. We learnt Thermodynamics and the relationship between heat and work, but failed to understand the consequences of gases of combustion and its impact on our environment.

There are two issues involved in burning a fossil fuel to generate electricity. The heat of combustion is an exothermic reaction and we get a certain amount of heat. Then we convert this heat energy into electrical energy and the overall efficiency of such conversion is about thirty-five percent. Only thirty-five percent of the heat input energy becomes electrical energy and the remaining sixty-five percent heat along with gases of combustion are released into atmosphere. Of course part of this heat is recovered in a commercial plant, but the bulk of heat is released into the atmosphere as greenhouse gases. We failed to understand the potential of Hydrogen even though we used Hydrocarbon for several decades. We even discovered Urea, the fertilizer that caused ‘green revolution’ in agriculture, using the same Hydrogen present in the Hydrocarbon feedstock. It is time for us to make best use of a fossil fuel to its most potential when we burn each kilogram of fuel. We should burn coal not just with air but also with steam so that we can generate Hydrogen rich gas that can run a gas turbine in a combined cycle or run our cars on roads. Such a conversion will lead to a substantial increase in energy efficiency as well as in greenhouse gas emission reduction. Governments in industrialized countries should make it a mandatory to convert all their power plants to syngas generation as described above. They should also discourage new plants using fossil fuels with punitive power tariffs and encourage renewable energy projects with higher tariffs. Governments can also impose similar tariffs for transportation depending upon the fuel used such as fossil fuel or Hydrogen.

Governments should encourage renewable energy projects such as solar and wind   to generate Hydrogen from water as centralized power plants and distribute DC (direct current) by rural electrification. If the country side is electrified using this system then, agriculture, business and industries can thrive in rural areas. Direct current (DC) distribution net work can be installed in rural areas and encourage people to use energy-efficient appliances such as Direct current air-conditioners with energy star ratings and tariffs. Governments can bring about these changes by adopting a ‘carrot and stick ‘policy to encourage renewable and discourage fossil fuels.

Solar energy is the key from which all other forms of energy emanate such as wind, geothermal and ocean thermal energy conversion system.  It is of paramount importance to increase the efficiency of renewable systems and improve energy efficiencies of appliances we use. It is simpler to use LED bulbs using a Direct current generated by Renewable Hydrogen. It is once again the Mother Nature that can come to the rescue of human beings through solar, wind and water to generate clean energy for the twenty-first century.

Energy generation and distribution is no longer a business or revenue issue but a moral and ethical issue for Governments. It is only people who can bring about such sweeping changes by electing the right Government who can care for the environment. The future generation will judge us only based on what kind of environment we leave them behind.

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