Energy efficient 'Bioethanol'production

The science and technology of Bioethanol production from starch or sugar is well-established. Brazil leads the world in Bioethanol production with a capacity of 16,500 million liters/yr followed by US with a capacity of 16,230 million liters/yr.India produces merely 300 million liters/yr as the fifth largest producer in the world.US consumes about 873 MM gallons/day of oil of which about 58% is imported. The US forecast for 2025 import of oil is 870MMgal/day and the President wants to replace imported oil from the Middle East by 75% -100MMgal/day.(Ref: US Environmental protection Agency,Cincinnati,Ohio). Currently bulk of the Bioethanol is produced in centralized plants. This is because an economical plant requires a production rate of 40-55 MMgal /day. Transportation of raw materials to long distance is uneconomical. Countries like India can substantially increase their sugar production and encourage small scale distilleries for the sole purpose of replacing imported oil. Large scale Bioetehanol production involves fermentation of molasses; a byproduct of sugar industry.Bioethanol can also be produced directly from cane sugar juice or from starch such as Corn or Tapioca. Molasses is diluted with water and inoculated by addition of yeast and other nutrients. The fermentation takes about 24 to 30 hours till the fermented broth has an alcohol content of 7.5 to 9.5% by volume. The fermented wash is then distilled in a separate distillation column. This alcohol which is 95-96% is known as rectified spirit. The rectified spirit is further passed though a Molecular sieve to remove moisture and to concentrate alcohol to 99.8% by volume. A spent wash of about 8 lits are generated per liters of Bioethanol.The spent wash will have a BOD (biological oxygen demand) value of 45,000ppm.This can be subject to Anaerobic digestion to generate ‘Bio gas’ with about 55% Methane value and the liquid BOD will be reduced to less than 5000ppm. This Biogas can be used to generate power for the process. This process is economical for a production of Bioethanol 40-55MMgal/day. But in countries like India the sugar cane molasses are available in smaller quantities and the sugar plants are scattered. Small scale distillatory can adopt ‘Per-evaporation’ method to concentrate ‘Bioethanol’.The advantage with ‘Perevaporation’ is the process is not limited by thermodynamic vapor-liquid equilibrium. The distilled alcohol with 96% alcohol can be separated by Perevaportion into streams containing Bioethanol 99+% and alcohol depleted water.Perevaporation is a membrane separation process and it serves as an alternative to distillation and molecular sieve and saves energy. The membrane process can be suitably designed for alcohol enrichment as well as dehydration and easily adoptable for smaller production of Bioethanol. Such process allows production of dehydrated Bioethanol which are suitable to use as a fuel in cars as a Gasoline blend without any engine modification. Production of Bioethanol from cane sugar molasses is cheaper than from corn starch. Countries like India should promote Bioethanol as an alternative fuel to gasoline and reduce their oil imports.

Bioethanol fuel for Fuelcell cars

Bioethanol has successfully substituted Gasoline as a fuel for cars both in the form of blends with Gasoline or individually as an Anhydrous Ethanol. This successful demonstration by Brazil opens up new generation of cars called flex-fuel cars that allow usage of various blends of Ethanol and Gasoline.Bioethanol can also be used to generate Hydrogen onsite by steam reformation so that even Fuel cell cars such as Honda FCX can be felled by Bioethanol.This makes Bioethanol unique as an alternative fuel for transportation. It also facilitates onsite power generation using Fuel cell, replacing diesel engines. Substitution of Gasoline by Bioethanol has several advantages over other alternative fuels. The biggest advantage with Bioethanol is, it is renewable and it allows reduction of greenhouse gases from the atmosphere and it will be eligible for Carbon credit. It can be produced by both developing as well as developed countries using locally available agriculture produces such as cane sugar, corn, tapiaco, sorghum etc. Hydrogen generated from Bioethanol is also free from Sulfur compounds normally associated with natural gas, making it an ideal fuel for Fuel cell application in cars, as well as for power generation using SOFC (solid oxide Fuel cell) or PAFC (Phosphoric acid Fuel cell).The resulting high purity Hydrogen 99.99% can be used as fuel for all type of transportation including Fuel cell Buses, scooters and even boats. The stoichometric reaction of steam reformation in presence of catalyst can be represented by the following chemical reaction: C2H5OH + 3 H2O---------- 6H2 + 2 CO2 The Ethanol and water mixture is preheated and the vaporized mixture is fed into a catalytic reactor. The resulting Hydrogen is contaminated with carbon monoxide. This gas mixture is separated using membrane such as Palladium to get Hydrogen with less than 50ppm CO as contaminant. Such purity is acceptable by Fuel cell such as SOFC as well as PAFC.In future a small micro-reactor for on-board reformation may be possible making Fuel cell cars with onboard liquid fuel storage. Commercial reformers consumes about 0.88 lits of Bioethanol of 96% purity to generate 1 Nm3 of Hydrogen with 60% conversion. This translates to $ 5.90 per Kg of Hydrogen. Fuel cell cars offer a mileage of 240 from 1 kg Hydrogen costing only $5.90. For onsite power generation 1 kg Hydrogen generates as much as 15Kw electricity and 20Kw heat .Onsite Hydrogen generation with steam reformation also facilitates using SOFC and PAFC for high temperature power generation applications. They are ideal for CHP (combined heat and power) applications for 24x7 operations like hospitals, hotels and super markets. These fuel cells are silent in operation without any emissions except water vapor. Governments should encourage Bioethanol production and distribution for both transportation and power generation. There is a fear that Ethanol could be diverted for potable purposes illegally depriving Governments of potential reveneues.But this can be solved by denaturing Bioethanol and making it unsuitable for potable purposes. Denaturants such Pyridine has no effect on steam reformation and number of denaturants are available. Such policies will allow transition from fossil fuels to Hydrogen or Bioethanol.This is a simple and straight forward step any Government can take irrespective of the size or type of a nation. But it requires political will, determination and leadership. Developing countries need not wait for big greenhouse emitters such as US, China and India to make a decision on their Carbon emissions but start introducing Bioethanol as fuel locally.

Sustainable Hydrogen from bio-waste

Substituting fossil fuels with Hydrogen is not only efficient but also sustainable in the long run. While efforts are on to produce Hydrogen at a cost in par with Gasoline or less using various methods, sustainability is equally important. We have necessary technology to convert piped natural gas to Hydrogen to generate electricity on site to power our homes and fuel our cars using Fuelcell.But this will not be a sustainable solution because we can no longer depend on piped natural gas because its availability is limited; and it is also a potent greenhouse gas. The biogas or land fill gas has the same composition as that of a natural gas except the Methane content is lower than piped natural gas. The natural gas is produced by Nature and comes out along with number of impurities such as Carbon dioxide, moisture and Hydrogen sulfide etc.The impure natural gas is cleaned and purified to increase the Methane content up to 90%, before it is compressed and supplied to the customers. The gas is further purified so that it can be liquefied into LNG (liquefied natural gas) to be transported to long distances or exported to overseas. When the natural gas is liquefied, the volume of gas is reduced about 600 times to its original volume, so that the energy density is increased substantially, in order to reduce the cost of transportation. The LNG can be readily vaporized and used at any remote location, where there is no natural gas pipelines are in existence or in operation. Similarly Hydrogen too can be liquefied into liquid Hydrogen. Our current focus is to reduce the cost of Hydrogen to the level of Gasoline or even less. Biogas and bio-organic materials are potential sources of Hydrogen and also they are sustianable.Our current production of wastes from industries, business and domestic have increased substantially creating sustainability isues.These wastes are also major sources of Greenhouse gases and also sources of many airborne diseses.They also cause depletion of valuable resources without a credible recycling mechanisms. For example, number of valuable materials including Gold, Silver, Platinum, Lead, Cadmium, Mercury and Lithium are thrown into municipal solid waste (MSW) and sewages. Major domestic wastes include food, paper, plastics and wood materials. Industrial wastes include many toxic chemicals including Mercury, Arsenic, tanning chemicals, photographic chemicals, toxic solvents and gases. The domestic and industrial effluents contain valuable materials such as Potassim, Phosphorous and Nitrates. We get these valuable resources from Nature, convert them into useful products and then throw them away as a waste. These valuable materials remain as elements without any change irrespective of the type of usages.Recyling waste materials and treatment of waste water and effluent is a very big business. Waste to wealth is a hot topic. The waste materials both organic and inorganic are too valuable to be wasted for two simple reasons. First, it pollutes our land, water and air; second, we need fresh resources and these resources are limited while our needs are expanding exponentially. It is not an option but an absolute necessity to recycle them to maintain sustainability. For example, most of the countries do not have Phosphorous resources, a vital ingredient for plant growth and food production. Bulk of the Phosphorus and Nitrates are not recovered from municipal waste water and sewage plants. We simply discharge them into sea at far away distance while the public is in dark and EPA shows a blind eye to such activities. Toxic Methane gases are leaking from many land fill sites and some of these sites were even sold to gullible customers as potential housing sites. Many new residents in these locations find later that their houses have been built on abandoned landfill sites. They knew only when the tap water becomes highly inflammable when lighting with a match stick. The levels of Methane were above the threshold limit and these houses were not fit for living. We have to treat wastes because we can recover valuable nutrients and also generate energy without using fresh fossil fuels. It is a win situation for everybody involved in the business of ‘waste to wealth’. These wastes have a potential to guarantee cheap and sustainable Hydrogen for the future. Biogas is a known technology that is generated from various municipal solid wastes and effluents. But current methods of biogas generation are not efficient and further cleaning and purifications are necessary. The low grade methane 40-55% is not suitable for many industrial applications except for domestic heating. The biogas generated by anaerobic digestion has to be scrubbed free of Carbon dioxide and Hydrogen sulfide to get more than 90% Methane gas so that it can be used for power generation and even for steam reforming to Hydrogen generation. Fuel cell used for onsite power generation and Fuel cell cars require high purity Hydrogen. Such Hydrogen is not possible without cleaning and purifying ‘Bio-gas’ significantly. Hydrogen generation from Biogas or from Bioethanol is a potential source of Hydrogen in the future.

Will Bioethanol and Hydrogen replace Gasoline?

Many universities, research and development institutions and industries are studying various biological processes to produce Hydrogen using different sources of organic materials such as Starch, Glucose, Bioethanol and cellulosic materials. However many of these technologies are at “proof of concept’ stages. Moreover these processes depend upon location and availability of specific raw materials in these locations. For example, Brazil has been very successful in the production of Bioethanol form sugar cane molasses and using it as the fuel for cars. Brazil has also successfully utilized Bioethanol as a substitute for Naphtha as a feedstock for the production of Ethylne, a precursor for several plastics such as PVC and Polyethylene and Glycols. Bioethanol is a classic example of biological process than can successfully substitute Gasoline. Many industrial raw materials are also derived from Sugar cane and Corn Starch. The main issue in substituting Gasoline with bio-chemicals is political in many countries. India has been producing industrial alcohol from sugarcane molasses for number of years but they are not be able successfully substitute Gasoline with Alcohol.They have to fix the price of Alcohol in relation to the price of Gasoline or Naptha.This pricing mechanism is critical. We have been using coal as the raw material for several decades not only to generate power but also to produce host of organic chemicals and fertilizers such as Urea, coal tar chemicals such as dyes and pharmaceuticals. These industries later switched over to oil and Gas. Now the world is facing depletion of fossil fuels at a faster rate. Greenhouse emission and global warming threats are looming large. There is a clear sign that the energy prices will sharply increase in the near future. Renewable energy projects are at early stages and their initial costs and cost of productions are much higher compared to fossil fuel based power generation. However biological processes and biofuels offer a glimpse of hope to get over the energy crisis and also to mitigate greenhouse gas emissions. Production of Biohydrogen using bio-organic materials such as starch, glucose and cellulosic materials are under development, but it may be a decade before they can be successfully commercialized. But production of Bioethanol and Biogas are well-known technologies. Generation of Biogas from agricultural waste, food waste and municipal solid waste and waste water are known technologies. However Methane the major constituents of biogas,is a potential greenhouse gas.The Biogas can be easily cleaned from other impurities such as Carbon dioxide and Hydrogen sulfide and can be readily converted to Hydrogen gas by steam reformation. This will substantially increase the energy efficiency of Biogas plants. Many developing countries can adopt these technologies on a wider scale and promote Bioethenaol and Biogas generation to substitute petroleum oil and gas. They can convert Gasoline cars into 100% Bioethanol (anhydrous) or blended with gasoline fuels for cars.These technologies are commercially available.Number of countries in Asia, Africa and South America produce starches such as Tapioca starch for industrial applications.Vegetable oils such as Jatropa and Castor oils are excellent for bio-fuels and lubricants.Though it is theoretically possible to substitute most of the petrochemicals with bio-organic materials,it is important that food products such as corn should not be diverted for commercial applications such as fuel. The coming decade will be a challenging one and Hydrogen generation from various biological organic materials can substitute fossil fuels at a much faster rate. A judicial mix of bio-energy and renewable energy such as solar and wind should help the world to overcome the challenges.

Hydrogen is the choice of Nature as the source of clean energy

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, has 25% Hydrogen by weight basis. It represents the maximum 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; it is more expensive to produce Bioethanol from corn 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 is 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 achieve 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 clean energy source 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 generation. 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.