Skip navigation

Category Archives: Syngas

There is so much discussion about Hydrogen as a source of clean energy because, it is the choice of Nature. Nature has provided us with fossil fuels which are Hydrocarbons, chemically represented by CxHy, Carbon and Hydrogen atoms. In the absence of Hydrogen in a Hydrocarbon, it is nothing but Carbon, which is an inert material. The Hydrocarbon gets its heating value only from the presence Hydrogen atom. The natural gas, now considered as the cleanest form of Hydrocarbon is represented by the chemical formula CH4, containing 25% Hydrogen by weight basis. It represents the largest Carbon to Hydrogen ratio at 1:4.This is the highest in any organic chemicals. In aromatic organic compounds such as Benzene, represented by C6H6, the Hydrogen content is only 7.69%.Even in Sugar which is an organic compound from Nature, represented chemically as C12H22O11 has only 8.27% Hydrogen. But Bioethanol, derived from sugar represented by C2H5OH has almost 13% Hydrogen.  Ethyl Alcohol known as ‘Bioethanol’ derived from sugar is blended with Gasoline (Hydrocarbon), for using as a fuel in cars in countries like Brazil. Brazil is the only country that does not depend on imported Gasoline for their cars. The same Bioethanol can also be derived from Corn starch. But the starch should first be converted into sugar before alcohol is derived; that is why it is more expensive to produce Bioethanol from starch than from cane sugar molasses. The climatic conditions of Brazil are more favorable for growing Cane sugar than corn.  Brazil is in a more advantageous position than North America, when it comes to Bioethanol. US is one of the largest consumer of Gasoline.US has imported 11.5 million barrels/day of oil in 2010.It has used 138.5 billion gallons of Gasoline (3.30billion barrels) in 2010) according to EIA. (US Energy Information Administration) It is estimated that Brazil’s sugar based Alcohol is 30% cheaper than US’s corn-based Alcohol. Brazil has successfully substituted Gasoline with locally produced alcohol .They also introduced ‘flexible fuel vehicles’ that can use various blends of Alcohol-Gasoline. Most of the Gasoline used in US has 10% Ethanol blend called E10 and E15, representing the percentage of Alcohol content in Gasoline. Brazil is the largest producers of Bioethanol in the world. Both Brazil and US account for 87.8% of Bioethanol production in the world in 2010 and 87.1% in 2011.Brazil is using Bioethanol blends of various proportions such as E20/E25/E100 (anhydrous alcohol) (Ref: Wikipedia). Almost all cars in Brazil use Bioethanol blended Gasoline and even 100% anhydrous Bioethanol are used for cars. Brazil has set an example as a ‘sustainable economy introducing alternative fuel’ to the rest of the world. The ‘bagasse’ from cane sugar is also used as a fuel as well in the production of ‘Biogas’, which helps Brazil to meet sustainability on renewable energy and greenhouse gas mitigation. The above example is a clear demonstration of sustainability because natural organic material such as sugar is the basic building block by which we can build our Sustainable clean energy of the future. The same Bioethnanol can easily be reformed for the production of Hydrogen gas to generate power and run Fuel cell cars. Many companies are trying to use chemicals such as metal Hydrides as a source of Hydrogen. For example, one company successfully demonstrated using Sodium Borohydride for Hydrogen production. Many companies are trying to find alternative sources of Hydrogen generation from water, including Photo-electrolysis using direct solar light and special photo catalyst materials. We know Nature produces sugar by using sun’s light, water and carbon dioxide from air by photosynthetic process. Can man duplicate this natural process and generate Hydrogen at the fraction of the cost by simply using water and sun’s light? The race is already on and only time can tell whether our pursuit for cheap and clean Hydrogen can become a commercial reality or just stay as an elusive dream.

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.

We have been using fossil fuels like diesel, petrol and natural gas for power generation and transportation from the time of industrial revolution. The basic fuel and the combustion technology are practically the same with efficiencies less than 40%. In fact we have become very complacent with both the fuel and the combustion technology and there were no major research and development on both the above issues. In fact we became completely dependent on these two issues and there was no real breakthrough either in substituting the fossil fuel or in the combustion technology. The basic reason behind this situation can be attributed to the discovery of electromagnetism, which opened the way for electricity generation as well as transportation. In both these industries, the key part is the motor which provided a rotary motion. This rotary motion generates electricity in turbines and such motion is created by combustion of a fuel, which is invariably a fossil fuel. We have carried on this for few decades before the emission of greenhouse started rising abnormally and became an issue.

We are now at cross roads wondering what the future holds for the world. Is it possible to carry on the business as usual or look for an alternative source of energy? We started looking at various sources of energy as an alternative. Any alternative energy source should meet two critical parameters namely the lower or no carbon emission and sustainability. Low carbon can be achieved by few methods. The immediate option is to maximize the energy efficiency of existing systems so that for the given input of fuel the output is much higher than what we have achieved all these years. But this increase in efficiency should be real to achieve the emission levels of greenhouse suggested by the UN panel on climate change.

The second option will be to switch over to different fuels with less carbon emission e.g., coal-fired power plants switching over to gas-fired power plants using combined cycle. Retrofitting organic Rankin cycle as a bottoming for steam turbines to squeeze out some extra energy. Decentralizing the power plants in a phased manner in favor of distributed energy systems where gas, instead of electricity, can be supplied to each industry, to generate their own power using CHP process. All these measures can help reduce the emission level but our dependency on fossil fuel will still continue.

W can look at a completely different fuel source and new technology for power generation and transportation. If we look at carefully there are not many alternative fuel sources except Hydrogen that could meet these limits. We are also trying to develop bio fuels. But biofuels are also organic chemicals with carbon backbone which will generate greenhouse emission. Moreover bio fuel sources such as palm oil, corn are also food sources. There is an indiscriminate deforestation and plantation of palm trees in tropical countries like Malaysia, Indonesia and PNG. The focus is now shifting to carbon based organic compounds like biofuel and biogas. This will create a situation where food crops will be substituted with energy crops creating food shortage.But the carbon dioxide level in the atmosphere may not be reduced drastically by these methods.

We need to develop an energy source which does not emit any carbon emission and at the same time we should be able to use existing technology to the possible extent. Only Hydrogen can meet these requirements. In the current situation it is impossible to substitute fossil fuels in a short span of time. We can cut fossil fuels by blending with Hydrogen to the most extent possible so that we can meet two goals. We can cut the carbon emission and at the same time we can deploy Hydrogen as a blended fuel with fossil fuel and not, pure Hydrogen. Since Hydrogen is a very light gas and readily forms an explosive mixture with oxygen, this opens up a new opportunity to develop Hydrogen assisted combustion process in power generation as well as in transportation. It will be easier to handle a mixture of natural gas and Hydrogen for combustion in Gas turbine, or spark ignited reciprocating engines, as well as, gasoline combustion engines in cars. This will also gives us an opportunity to develop advanced and competitive systems like Fuel cell as an alternative technology for combustion process in due course of time.

The hydrogen assisted combustion technology is much easier, faster and economical and at the same time cut the greenhouse emission to an accepted level. But the source of such Hydrogen cannot be natural gas but only renewable sources. The renewable technologies such as solar, wind, geothermal, OTEC (ocean thermal energy conversion) should generate renewable Hydrogen. This is the key for sustainability as well as for greenhouse gas mitigation. These two benefits are too attractive to ignore and it is time we move from total fossil fuel to Hydrogen blended fossil fuel. The blended fuel along with the energy efficiency measures suggested above should go hand in hand, so that we may get over this turbulent period of financial crisis and global warming.

It is also possible that Hydrogen assisted combustion be adopted for coal-fired power plants by simply firing coal slurry, finely powdered coal blended with water and conveyed pneumatically for firing boilers and also for gasification process to generate syngas for IGCC (Integrated gasification and combined cycle) applications. Syngas production will be critical in the near future for a smoother transition from fossil economy to Hydrogen economy irrespective of the route we adopt.

%d bloggers like this: