Food Waste-to-Energy

The waste management hierarchy suggests that reduce, reuse and recycling should always be given preference in a typical waste management system. However, these options cannot be applied uniformly for all kinds of wastes. For examples, organic waste is quite difficult to deal with using the conventional 3R strategy.  Of the different types of organic wastes available, food waste holds the highest potential in terms of economic exploitation as it contains high amount of carbon and can be efficiently converted into biogas and organic fertilizer.

There are numerous places which are the sources of large amounts of food waste and hence a proper food-waste management strategy needs to be devised for them to make sure that either they are disposed off in a safe manner or utilized efficiently. These places include hotels, restaurants, malls, residential societies, college/school/office canteens, religious mass cooking places, airline caterers, food and meat processing industries and vegetable markets which generate organic waste of considerable quantum on a daily basis.

The anaerobic digestion technology is highly apt in dealing with the chronic problem of organic waste management in urban societies. Although the technology is commercially viable in the longer run, the high initial capital cost is a major hurdle towards its proliferation. The onus is on the governments to create awareness and promote such technologies in a sustainable manner. At the same time, entrepreneurs, non-governmental organizations and environmental agencies should also take inspiration from successful food waste-to-energy projects in other countries and try to set up such facilities in Indian cities and towns.

Renewable Energy in Jordan

Jordan has been the leader in the development of renewable energy systems in the Middle East, with its tremendous renewable energy potential in the form of wind, solar, biomass and waste-to-energy. Renewable energy accounted for about 2% of the energy consumption in 2009, and the country has set ambitious targets to raise this share to 7% in 2015 and 10% in 2020. To achieve these figures, more than 1200MW of renewable energy projects are expected to be implemented in the coming decade, with emphasis on solar and wind energy. Jordan will require investments in the range of USD 1.4 – 2.1 billion within the next 10 years to realize its clean energy potential. The Government of Jordan has pledged its full support to the developmental initiatives in the renewable energy and energy efficiency sector through continuous cooperation with international partners, donors and private investors.

For full access to the Jordan country report, please contact the author at salman@bioenergyconsult.com

Biomass CHP

Biomass conversion technologies transform a variety of wastes into heat, electricity and biofuels by employing a host of strategies. Biomass fuels are typically used most efficiently and beneficially when generating both power and heat through a Combined Heat and Power (or Cogeneration) system. Combined Heat and Power (CHP) technologies are well suited for sustainable development projects, because they are, in general, socio-economically attractive and technologically mature and reliable.

In developing countries, cogeneration can easily be integrated in many industries, especially agriculture and food-processing, taking advantage of the biomass residues of the production process. This has the dual benefits of lowering fuel costs and solving waste disposal issues. Prime movers for CHP units include reciprocating engines, combustion or gas turbines, steam turbines, microturbines, and fuel cells. The success of any biomass-fuelled CHP project is heavily dependent on the availability of a suitable biomass feedstock freely available in urban and rural areas.

Waste-to-Energy in the Tannery Industry

The energy generated by anaerobic digestion or gasification of tannery wastes can be put to beneficial use, in both drying the wastes and as an energy source for the tannery’s own requirements, CHP or electricity export from the site. A large amount of the energy recovered is surplus to the energy conversion process requirements and can be reused by the tannery directly. Infact, implementation of waste-to-energy systems have the potential to make the industry self-sufficient in terms of thermal energy requirements. Waste-to-energy plant in a tannery promotes the production of electricity from decentralized renewable energy sources, apart from resolving serious environmental issues posed by leather industry wastes.

Energy Recovery from Tannery Wastes

The conventional leather tanning technology is highly polluting as it produces large amounts of organic and chemical pollutants. Wastes generated by the leather processing industries pose a major challenge to the environment. According to conservative estimates, about 600,000 tons per year of solid waste are generated worldwide by leather industry and approximately 40–50% of the hides are lost to shavings and trimmings.

The energy generated by anaerobic digestion or gasification of tannery wastes can be put to beneficial use, in both drying the wastes and as an energy source for the tannery’s own requirements, CHP or electricity export from the site. A large amount of the energy recovered is surplus to the energy conversion process requirements and can be reused by the tannery directly. Infact, implementation of waste-to-energy systems have the potential to make the industry self-sufficient in terms of thermal energy requirements. Tanneries are major energy users, and requires up to 30 kW of energy to produce a single finished hide. Thus, waste-to-energy plant in a tannery promotes the production of electricity from decentralized renewable energy sources, apart from resolving serious environmental issues posed by leather industry wastes.

To read the full article, please visit http://www.altenergymag.com/emagazine.php?art_id=1499

BioEnergy Consult- Provider of Waste-to-Energy Solutions

BioEnergy Consult is committed to the development of sustainable energy systems based on non-food renewable resources and different types of wastes. Our primary mission is to promote Renewable Energy and Sustainable Development worldwide, particularly in developing countries. We are actively engaged in the conceptualization, promotion, implementation, development and financing of Biomass Energy, Waste-to-Energy, Sustainable Biofuels, Waste Management and Alternative Energy ventures in different parts of the world.

BioEnergy Consult promises to address many environmental issues, especially global warming and greenhouse gases emissions, and foster sustainable development among poor communities. The potential role of alternative energy systems in transforming global energy outlook, and addressing climate change concerns, is enormous. We endeavour to bring Sustainable Energy Technologies within the reach of developing countries and to create a mass awareness about the challenges posed by environmental issues like Climate Change and Global Warming.

BioEnergy Consult is an organization with a well-defined mission: To provide cost-effective sustainable solutions through environmentally-safe and well-proven Alternative Energy Systems and Waste-to-Energy Technologies to ensure better Quality of Life.

BioEnergy Consult welcomes inquiries, comments and feedback from entrepreneurs, technology firms, governments, NGOs, investors, social groups, researchers and general public. Please feel free to contact us for business inquiries, partnership, collaboration, expert opinion, discussion or information.

Email: info@bioenergyconsult.com

Website: http://www.bioenergyconsult.com

Cellulosic Ethanol Feedstock in India

In India, the leading biofuel feedstock today is sugarcane molasses, which is processed to yield bioethanol that can be blended into gasoline (petrol). Sugarcane requires good land and large amounts of irrigation water, which are difficult for the poor to obtain. The bioethanol industry buys its molasses feedstock from the sugar factories. Sugar is the main objective of the sugarcane industry; molasses are simply a byproduct. As such, the unreliability of supply of molasses is a major constraint to biofuels development based on this feedstock.

Even though India is an agrarian economy, the energy potential of agricultural residues has not been realized till now by policy-makers and masses. Most of the biomass wastes are inefficiently used for domestic purposes in absence of reliable and cheaper source of energy. The main crops produced in India are wheat, maize, rice, sorghum, sugarcane and barley. India is among the market leaders in the production of these crops and has tremendous potential to convert lignocellulosic crop residues into ethanol.

Socio-economic and Environmental Benefits of Waste-to-Energy

Waste-to-energy technologies hold the potential to create renewable energy from waste matter, including municipal solid waste, industrial waste, agricultural waste, and industrial byproducts. Besides recovery of substantial energy, these technologies can lead to a substantial reduction in the overall waste quantities requiring final disposal, which can be better managed for safe disposal in a controlled manner. Waste-to-energy systems can contribute substantially to GHG mitigation through both reductions of fossil carbon emissions and long-term storage of carbon in biomass wastes. Modern waste-to-energy systems options offer significant, cost-effective and perpetual opportunities for greenhouse gas emission reductions.

Additional benefits offered are employment creation in rural areas, reduction of a country’s dependency on imported energy carriers (and the related improvement of the balance of trade), better waste control, and potentially benign effects with regard to biodiversity, desertification, recreational value, etc. In summary, waste-to-energy can significantly contribute to sustainable development both in developed and less developed countries. Waste-to-energy is not only a solution to reduce the volume of waste that is and provide a supplemental energy source, but also yields a number of social benefits that cannot easily be quantified.

Biological Desulphurization of Biogas

Desulphurization of biogas can be performed by micro-organisms. Most of the sulphide oxidising micro-organisms belong to the family of Thiobacillus. For the microbiological oxidation of sulphide it is essential to add stoichiometric amounts of oxygen to the biogas. Depending on the concentration of hydrogen sulphide this corresponds to 2 to 6 % air in biogas.

The simplest method of desulphurization is the addition of oxygen or air directly into the digester or in a storage tank serving at the same time as gas holder. Thiobacilli are ubiquitous and thus systems do not require inoculation. They grow on the surface of the digestate, which offers the necessary micro-aerophilic surface and at the same time the necessary nutrients. They form yellow clusters of sulphur. Depending on the temperature, the reaction time, the amount and place of the air added the hydrogen sulphide concentration can be reduced by 95 % to less than 50 ppm.

Measures of safety have to be taken to avoid overdosing of air in case of pump failures. Biogas in air is explosive in the range of 6 to 12 %, depending on the methane content). In steel digesters without rust protection there is a small risk of corrosion at the gas/liquid interface.

Primary Biomass Conversion Technologies – Thermochemical

A wide range of technologies exists to convert the energy stored in biomass to more useful forms of energy. These technologies can be classified according to the principal energy carrier produced in the conversion process. Carriers are in the form of heat, gas, liquid and/or solid products, depending on the extent to which oxygen is admitted to the conversion process (usually as air). The three principal methods of thermo-chemical conversion corresponding to each of these energy carriers are combustion in excess air, gasification in reduced air, and pyrolysis in the absence of air.

Conventional combustion technologies raise steam through the combustion of biomass. This steam may then be expanded through a conventional turbo-alternator to produce electricity. A number of combustion technology variants have been developed. Underfeed stokers are suitable for small scale boilers up to 6 MWth. Grate type boilers are widely deployed. They have relatively low investment costs, low operating costs and good operation at partial loads. However, they can have higher NOx emissions and decreased efficiencies due to the requirement of excess air, and they have lower efficiencies.

Fluidized bed combustors (FBC), which use a bed of hot inert material such as sand, are a more recent development. Bubbling FBCs are generally used at 10-30 MWth capacity, while Circulating FBCs are more applicable at larger scales. Advantages of FBCs are that they can tolerate a wider range of poor quality fuel, while emitting lower NOx levels.

Gasification of biomass takes place in a restricted supply of oxygen and occurs through initial devolatilization of the biomass, combustion of the volatile material and char, and further reduction to produce a fuel gas rich in carbon monoxide and hydrogen. This combustible gas has a lower calorific value than natural gas but can still be used as fuel for boilers, for engines, and potentially for combustion turbines after cleaning the gas stream of tars and particulates. If gasifiers are ‘air blown’, atmospheric nitrogen dilutes the fuel gas to a level of 10-14 percent that of the calorific value of natural gas. Oxygen and steam blown gasifiers produce a gas with a somewhat higher calorific value. Pressurized gasifiers are under development to reduce the physical size of major equipment items.

A variety of gasification reactors have been developed over several decades. These include the smaller scale fixed bed updraft, downdraft and cross flow gasifiers, as well as fluidized bed gasifiers for larger applications. At the small scale, downdraft gasifiers are noted for their relatively low tar production, but are not suitable for fuels with low ash melting point (such as straw). They also require fuel moisture levels to be controlled within narrow levels.

Pyrolysis is the term given to the thermal degradation of wood in the absence of oxygen. It enables biomass to be converted to a combination of solid char, gas and a liquid bio-oil. Pyrolysis technologies are generally categorized as “fast” or “slow” according to the time taken for processing the feed into pyrolysis products. These products are generated in roughly equal proportions with slow pyrolysis. Using fast pyrolysis, bio-oil yield can be as high as 80 percent of the product on a dry fuel basis. Bio-oil can act as a liquid fuel or as a feedstock for chemical production. A range of bio-oil production processes are under development, including fluid bed reactors, ablative pyrolysis, entrained flow reactors, rotating cone reactors, and vacuum pyrolysis.

Biomass Energy and its Importance

Biomass can play a dual role in greenhouse gas mitigation related to the objectives of the UNFCCC, i.e. as an energy source to substitute for fossil fuels and as a carbon store. However, compared to the maintenance and enhancement of carbon sinks and reservoirs, it appears that the use of bioenergy has so far received less attention as a means of mitigating climate change. Modern bioenergy options offer significant, cost-effective and perpetual opportunities toward meeting emission reduction targets while providing additional ancillary benefits. Moreover, via the sustainable use of the accumulated carbon, bioenergy has the potential for resolving some of the critical issues surrounding long-term maintenance of biotic carbon stocks.

It has become clear that biomass can contribute substantially to GHG mitigation through both reductions of fossil carbon emissions and long-term storage of carbon in biomass. All forms of biomass utilization can be considered part of a closed carbon cycle. The mass of biospheric carbon involved in the global carbon cycle provides a scale for the potential of biomass mitigation options; whereas fossil fuel combustion accounts for some 6 Gigatons of carbon (GtC) release to the atmosphere annually, the net amount of carbon taken up from and released to the atmosphere by terrestrial plants is around 60 GtC annually (corresponding to a gross energy content of approximately 2100 EJ p.a., of which bioenergy is a part), and an estimated 600 GtC is stored in the terrestrial living biomass.

The Importance of Bio-Oil

Bio-oil is a dark brown liquid and has a similar composition to biomass. It has a much higher density than woody materials which reduces storage and transport costs. Bio-oil is not suitable for direct use in standard internal combustion engines. Alternatively, the oil can be upgraded to either a special engine fuel or through gasification processes to a syngas and then bio-diesel.

Bio-oil is particularly attractive for co-firing because it can be more readily handled and burned than solid fuel and is cheaper to transport and store.  Co-firing of bio-oil has been demonstrated in 350 MW gas fired power station in Holland, when 1% of the boiler output was successfully replaced. It is in such applications that bio-oil can offer major advantages over solid biomass and gasification due to the ease of handling, storage and combustion in an existing power station when special start-up procedures are not necessary. In addition, bio-oil is also a vital source for a wide range of organic compounds and speciality chemicals.