Google analytics tag
Sunday, December 16, 2012
A new concept known as “hydraulic fracturing “ to enhance the recovery of land fill gas from new and existing land fill sites have been tested jointly by a Dutch and a Canadian company. They claim it is now possible to recover such gas economically and liquefy them into Bio-LNG to be used as a fuel for vehicles and to generate power.Most biofuels around the world are now made from energy crops like wheat, maize, palm oil, rapeseed oil etc and only a minor part is made from waste. But such a practice in not sustainable in the long run considering the anticipated food shortage due to climate changes. The EU wants to ban biofuels that use too much agricultural land and encourage production of biofuels that do not use food material but waste materials. Therefore there is a need to collect methane gas that is emitted by land fill sites more efficiently and economically and to compete with fossil fuels. There are approximately 150,000 landfills in Europe with approximately 3–5 trillion cubic meters of waste (Haskoning 2011). All landfills emit landfill gas; the contribution of methane emissions from landfills is estimated to be between 30 and 70 million tons each year. Landfills contributed an estimated 450 to 650 billion cubic feet of methane per year (in 2000) in the USA. One can either flare landfill gas or make electricity with landfill gas. But it is prudent to produce the cleanest and cheapest liquid biofuel namely “Bio-LNG”. Landfill gas generation: how do these bugs do their work? Researchers had a hard time figuring out why landfills do not start out as a friendly environment for the organisms that produce methane. Now new research from North Carolina State University points to one species of microbe that is paving the way for other methane producers. The starting bug has been found. That opens the door to engineer better landfills with better production management. One can imagine a landfill with real economic prospects other than getting the trash out of sight. The NCSU researchers found that an anaerobic bacterium called Methanosarcina barkeri appears to be the key microbe. The following steps are involved in the formation of landfill gas is shown in the diagram Phase 1: oxygen disappears, and nitrogen Phase 2: hydrogen is produced and CO2 production increases rapidly. Phase 3: methane production rises and CO2 production decreases. Phase 4: methane production can rise till 60%. Phases 1-3 typically last for 5-7 years. Phase 4 can continue for decades, rate of decline depending on content. Installation of landfill gas collection system: A quantity of wells is drilled; the wells are (inter) connected with a pipeline system. Gas is guided from the wells to a facility, where it is flared or burnt to generate electricity. A biogas engine exhibits 30-40% efficiency. Landfills often lack access to the grid and there is usually no use for the heat. The alternative: make bio-LNG instead and transport the bio-LNG for use in heavy duty vehicles and ships or applications where you can use all electricity and heat. Bio-LNG: what is it? Bio-LNG is liquid bio-methane (also: LBM). It is made from biogas. Biogas is produced by anaerobic digestion. All organic waste can rot and can produce biogas, the bacteria does the work. Therefore biogas is the cheapest and cleanest biofuel that can be generated without competing with food or land use. For the first time there is a biofuel, bio-LNG, a better quality fuel than fossil fuel. The bio-LNG production process: Landfill gas is produced by anaerobic fermentation in the landfill. The aim is to produce a constant flow of biogas with high methane content. The biogas must be upgraded, i.e. removal of H2S, CO2 and trace elements; In landfills also siloxanes, nitrogen and Cl/F gases. The bio-methane must be purified (maximum 25/50ppm CO2, no water) to prepare for liquefaction. The cold box liquefies pure biomethane to bio-LNG Small scale bio-LNG production using smarter methods. •Use upgrading modules that do not cost much energy. •Membranes which can upgrade to 98-99.5 % methane are suitable. •Use a method for advanced upgrading that is low on energy demand. •Use a fluid / solid that is allowed to be dumped at the site. •Use cold boxes that are easy to install and low on power demand. •Use LNG tank trucks as storage and distribution units. •See if co-produced CO2 can be sold and used in greenhouses or elsewhere. •Look carefully at the history and present status of the landfill. What was holding back more projects? Most flows of landfill gas are small (hundreds of Nm3/hour), so economy of scale is generally not favorable. Technology in upgrading and liquefaction has evolved, but the investments for small flows during decades cannot be paid back. Now there is a solution: enhanced gas recovery by hydraulic fracturing. Holland Innovation Team and Fracrite Environmental Ltd. (Canada) has developed a method to increase gas extraction from landfill 3-5 times. Hydraulic fracturing increases landfill gas yield and therefore economy of scale for bio-LNG production The method consists of a set of drillings from which at certain dept the landfill is hydraulically broken. This means a set of circular horizontal fractures are created from the well at preferred depths. Sand or other materials are injected into the fractures. Gas gathers from below in the created interlayers and flows into the drilled well. In this way a “guiding” circuit for landfill gas is created. With a 3-5 fold quantity of gas, economy of scale for bio-LNG production will be reached rapidly. Considering the multitude of landfills worldwide this hydraulic fracturing method in combination with containerized upgrading and liquefaction units offers huge potential. The method is cost effective, especially at virgin landfills, but also at landfill with decreasing amounts of landfill gas. Landfill gas fracturing pilot (2009). • Landfill operational from 1961-2005 • 3 gas turbines, only 1 or 2 in operation at any time due to low gas extraction rates • Only 12 of 60 landfill gas extraction wells still producing methane • Objective of pilot was to assess whether fracturing would enhance methane extraction rates Field program and preliminary results: Two new wells drilled into municipal wastes and fractured (FW60, FW61). Sand Fractures at 6, 8, 10, 12 m depth in wastes with a fracture radius of 6 m. Balance gases believed to be due to oxygenation effects during leachate and Groundwater pumping. Note: this is entirely different from deep fracking in case of shale gas! Conceptual Bioreactor Design: The conceptual design is shown in the figures. There are anaerobic conditions below the groundwater table, but permeability decreases because of compaction of the waste. Permeability increases after fracking and so does the quantity of landfill gas and leachate. Using the leachate by injecting this above the groundwater table will introduce anaerobic conditions in an area where up till then oxygen prevailed and so prevented landfill gas formation It can also be done in such a systematic way, that all leachate which is extracted, will be disposed off in the shallow surrounding wells above the groundwater table. One well below the groundwater table is fracked, the leachate is injected at the corners of a square around the deeper well. Sewage sludge and bacteria can be added to increase yield further Improving the business case further: A 3-5 fold increased biogas flow will improve the business case due to increasing Economy of scale. The method will also improve landfill quality and prepare the landfill for other uses. When the landfill gas stream dries up after 5 years or so, the next landfill can be served by relocating the containerized modules (cold boxes and upgrading modules). The company is upgrading with a new method developed in-house, and improving landfill gas yield by fracking with smart materials. EC recommendations to count land fill gas quadrupled for renewable fuels target and the superior footprint of bio-LNG production from landfills are beneficial for immediate start-ups
Wednesday, July 25, 2012
Wednesday, July 11, 2012
Friday, April 20, 2012
Friday, April 6, 2012
We live in a technological world where fuel and power play a critical role in shaping our lives and building our nations. The growth of a nation is measured in terms of fuel and power usage; yet there are many challenges and uncertainties in fuel supply and power generation technologies in recent past due to environmental implications. Fossil fuels accelerated our industrial growth and the civilization. But diminishing supply of oil and gas, global warming, nuclear disasters, social upheavals in the Arabian countries, financial problems, and high cost of renewable energy have created an uncertainty in the energy supply of the future. The future cost of energy is likely to increase many folds yet nobody knows for certain what will be the costs of energy for the next decade or what will be the fuel for our cars. Renewable energy sources like solar and wind seem to be getting popular among people but lack of concrete Government plans and financial incentives for renewable, are sending mixed signals for investors. Recently number of solar industries in Germany are facing bankruptcy due to withdrawal of Government subsidies. Wind energy in India has got a setback due to withdrawal of Government financial support. Renewable industries are at their infant stages of growth both technologically and financially. These industries will face a natural death in the absence of Government supports and incentives. Individuals, small businesses and industries are unable to plan their future due to above uncertinities.In a globalised world such problem have to be tackled jointly and collectively. But that too looks unlikely due to ideological, political and social differences between countries. In the absence of any clear path forward, a common man is left with no alternative but find solutions for himself. Individuals can form small groups to produce their own fuel and generate their own power. There has never been a right moment in our history for such ventures. It can be easily done by people from rural areas especially in farming communities. They can set an example and rest of the country can follow. This will also help preventing mass migration from rural areas to cities, especially in China and India. They neglect their farms and migrate to cities to work in electronic industries for a better life. The farming communities can form groups and generate their own ‘Biogas’ or ‘Bioethanol’ from a common facility to fuel their cars and power their homes without any Government incentives and political interefernces.Making ‘Bioethanol’ from cane sugar molasses, beet sugar, corn, tapioca or sorghum on a small or medium scale is a straight forward method. Fermentation and distillation is a well known technology. It is controlled by Government excise departments for revenue purpose but Government can certainly allow farms or individuals to make their own ‘Bioethanol’ for their cars. Farms can generate their own 'Biogas’ from manure, agriculture wastes, food waste and waste water treatment facilities and generate their own power and supply biogas for heating and cooking for their communities. Governments should allow people to make their own choices and decisions instead of controlling everything, especially when they are unable to solve a problem. Countries like India should encourage farming communities in groups to set up their own ‘Bioethanol’ and ‘Biogas’ plants and allow import of flex-fuel cars for Ethanol blends of various proportions. Alcohol has been a a’taboo’in many countries for several years but with current uncertainties with supply of fuel and power, Government can certainly remove such ‘taboo’ by highlighting the value of ‘Bioethanol as a source of fuel.Goevernments can forgo their excise revenue by allowing people to make their own fuel. Alternatively, they should provide incentives and subsidies for renewable energy developments. They cannot refuse both and still hope to continue in power because people will sooner or later throw them out of power. After all Governments are elected by people to address their problems.
Friday, March 30, 2012
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.
Thursday, March 29, 2012
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.