Biogas and Biomethane Gains Wider Acceptance

Reblogged from thekitchenreview:

Biogas is a wonderfully flexible and renewable form of vigor and it can be used as a construction block to make not only a wide collection of liquid fuels, but also organic chemicals and even plastics. The biogas digestion (anaerobic digestion) process can be installed and run at the household level with simple training and support, and it can also be advanced in huge projects to anaerobic make community and district anaerobic digestion plants. These can take up to 100,000 tons per year of organic waste …

Transforming food waste into energy

Reblogged from Healthy Grill USA:

Anaerobic digestion, which is commonly used to treat wastewater solids, naturally produces methane as it breaks down organic matter. Harnessing methane to produce heat, electric power or biofuel (also known as biomethane)—and offset facility power needs— is becoming an important energy management option. Divert organic matter – stuff made from plants and animals, such as food waste and yard clippings – away from landfills and transform it into energy is one of the methods that will bring great results. …

Solid Waste-to-Energy: Is It R&D or Market Ready?

Reblogged from BarryOnEnergy:

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Waste-to-Energy is a multifaceted concept; it means different things to different people, is underestimated in complexity and questionable in terms of profitability and carbon neutrality.  Waste can be solid or liquid; gaseous waste products are referred to as emissions. Energy can be a stream of electrons injected into the grid as electricity or combustible fuel commodities such as ethanol or synthetic fuels. The emissions and the restriction thereof, from converting solid waste into energy have a …

Major Obstacles in India’s Biodiesel Program

The unavailability of sufficient feedstock and lack of R&D to evolve high-yielding drought tolerant Jatropha seeds have been major stumbling blocks. In addition, smaller land holdings, ownership issues with government or community-owned wastelands, lackluster progress by state governments and negligible commercial production of biodiesel have hampered the efforts and investments made by both private and public sector companies.

Another major obstacle in implementing the biodiesel programme has been the difficulty in initiating large-scale cultivation of Jatropha. The Jatropha production program was started without any planned varietal improvement program, and use of low-yielding cultivars made things difficult for smallholders. The higher gestation period of biodiesel crops (3–5 years for Jatropha and 6–8 years for Pongamia) results in a longer payback period and creates additional problems for farmers where state support is not readily available. The Jatropha seed distribution channels are currently underdeveloped as sufficient numbers of processing industries are not operating. There are no specific markets for Jatropha seed supply and hence the middlemen play a major role in taking the seeds to the processing centres and this inflates the marketing margin.

 Biodiesel distribution channels are virtually non-existent as most of the biofuel produced is used either by the producing companies for self-use or by certain transport companies on a trial basis. Further, the cost of biodiesel depends substantially on the cost of seeds and the economy of scale at which the processing plant is operating. The lack of assured supplies of feedstock supply has hampered efforts by the private sector to set up biodiesel plants in India. As of now, only two firms, Naturol Bioenergy Limited and Southern Online Biotechnologies, have embarked on commercial-scale biodiesel projects, both in the southern state of Andhra Pradesh. In the absence of seed collection and oil extraction infrastructure, it becomes difficult to persuade entrepreneurs to install trans-esterification plants.

Thailand’s Biomass Energy Scenario

Thailand’s annual energy consumption has risen sharply during the past decade and will continue its upward trend in the years to come. While energy demand has risen sharply, domestic sources of supply are limited, thus forcing a significant reliance on imports. To face this increasing demand, Thailand needs to produce more energy from its own renewable resources, particularly biomass wastes derived from agro-industry, such as bagasse, rice husk, wood chips, livestock and municipal wastes.

In 2005, total installed power capacity in Thailand was 26,430 MW. Renewable energy accounted for about 2 percent of the total installed capacity. In 2007, Thailand had about 777 MW of electricity from renewable energy that was sold to the grid. Several studies have projected that biomass wastes can cover up to 15 % of the energy demand in Thailand (Thailand-Danish Country Programme for Environmental Assistance 1998-2001, Ministry of Environment and Energy, 2000). These estimations are primarily made from biomass waste from the extraction part of agricultural activities, and for large scale agricultural processing of crops etc. – as for instance saw and palm oil mills – and do not include biomass wastes from SMEs in Thailand. Thus, the energy potential of biomass waste can be much larger if these resources are included. The major biomass resources in Thailand include the following:

• Woody biomass residues from forest plantations
• Agricultural residues (rice husk, bagasse, corn cobs, etc.)
• Wood residues from wood and furniture industries    (bark, sawdust, etc.)
• Biomass for ethanol production (cassava, sugar cane, etc.)
• Biomass for biodiesel production (palm oil, jatropha oil, etc.)
• Industrial wastewater from agro-industry
• Livestock manure
• Municipal solid wastes and sewage

Thailand’s vast biomass potential has been partially exploited through the use of traditional as well as more advanced conversion technologies for biogas, power generation, and biofuels. Rice, sugar, palm oil, and wood-related industries are the major potential biomass energy sources. The country has a fairly large biomass resource base of about 60 million tons generated each year that could be utilized for energy purposes, such as rice, sugarcane, rubber sheets, palm oil and cassava. Biomass has been a primary source of energy for many years, used for domestic heating and industrial cogeneration. For example, paddy husks are burned to produce steam for turbine operation in rice mills; bagasse and palm residues are used to produce steam and electricity for on-site manufacturing process; and rubber wood chips are burned to produce hot air for rubber wood seasoning.

In addition to biomass residues, wastewater containing organic matters from livestock farms and industries has increasingly been used as a potential source of biomass energy. Thailand’s primary biogas sources are pig farms and residues from food processing. The production potential of biogas from industrial wastewater from palm oil industries, tapioca starch industries, food processing industries, and slaughter industries is also significant. The energy-recovery and environmental benefits that the KWTE waste to energy project has already delivered is attracting keen interest from a wide range of food processing industries around the world.

Anaerobic Digestion of Agricultural Residues

The main problem with anaerobic digestion of crop residues is that most of the agricultural residues are lignocellulosic with low nitrogen content. To improve the digestibility of crop residues, pre-treatment methods like size reduction, electron irradiation, heat treatment, enzymatic action etc are necessary. For optimizing the C/N ratio of agricultural residues, co-digestion with sewage sludge, animal manure or poultry litter is recommended.

Several organic wastes from plants and animals have been exploited for biogas production as reported in the literature. Plant materials include agricultural crops such as sugar cane, cassava, corn etc, agricultural residues like rice straw, cassava rhizome, corn cobs etc, wood and wood residues (saw dust, pulp wastes, and paper mill. Others include molasses and bagasse from sugar refineries, waste streams such as rice husk from rice mills and residues from palm oil extraction and municipal solid wastes, etc. However, plant materials such as crop residues are more difficult to digest than animal wastes (manures) because of difficulty in achieving hydrolysis of cellulosic and lignocellulosic constituents.

Crop residues can be digested either alone or in co-digestion with other materials, employing either wet or dry processes. In the agricultural sector one possible solution to processing crop biomass is co-digestion together with animal manures, the largest agricultural waste stream. In addition to the production of renewable energy, controlled anaerobic digestion of animal manures reduces emissions of greenhouse gases, nitrogen and odour from manure management, and intensifies the recycling of nutrients within agriculture.

In co-digestion of plant material and manures, manures provide buffering capacity and a wide range of nutrients, while the addition of plant material with high carbon content balances the carbon to nitrogen (C/N) ratio of the feedstock, thereby decreasing the risk of ammonia inhibition. The gas production per digester volume can be increased by operating the digesters at a higher solids concentration. Batch high solids reactors, characterized by lower investment costs than those of continuously fed processes, but with comparable operational costs, are currently applied in the agricultural sector to a limited extent.

Concept of Biorefinery

A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and value-added chemicals from biomass. The biorefinery concept is analogous to today’s petroleum refinery, which produces multiple fuels and products from petroleum.By producing several products, a biorefinery takes advantage of the various components in biomass and their intermediates, therefore maximizing the value derived from the biomass feedstock. A biorefinery could, for example, produce one or several low-volume, but high-value, chemical products and a low-value, but high-volume liquid transportation fuel such as biodiesel or bioethanol. At the same time, it can generate electricity and process heat, through CHP technology, for its own use and perhaps enough for sale of electricity to the local utility. The high value products increase profitability, the high-volume fuel helps meet energy needs, and the power production helps to lower energy costs and reduce GHG emissions from traditional power plant facilities.

There are several platforms which can be employed in biorefineries with the major ones being the sugar platform and the thermochemical platform (also known as syngas platform). Sugar platform biorefineries breaks down biomass into different types of component sugars for fermentation or other biological processing into various fuels and chemicals. On the other hand, thermochemical biorefineries transform biomass into synthesis gas (hydrogen and carbon monoxide) or pyrolysis oil.

The thermochemical biomass conversion process is complex, and uses components, configurations, and operating conditions that are more typical of petroleum refining. Biomass is converted into syngas, and syngas is converted into an ethanol-rich mixture. However, syngas created from biomass contains contaminants such as tar and sulphur that interfere with the conversion of the syngas into products. These contaminants can be removed by tar-reforming catalysts and catalytic reforming processes. This not only cleans the syngas, it also creates more of it, improving process economics and ultimately cutting the cost of the resulting ethanol.

BioMethane

The typical composition of raw biogas does not meet the minimum CNG fuel specifications. In particular, the CO₂ and sulfur content in raw biogas is too high for it to be used as vehicle fuel without additional processing. Biogas that has been upgraded to biomethane by removing the H₂S, moisture, and CO₂ can be used as a vehicular fuel. Biomethane is less corrosive than biogas, apart from being more valuable as a fuel.

Since production of such fuel typically exceeds immediate on-site demand, the biomethane must be stored for future use, usually either as compressed biomethane (CBM) or liquefied biomethane (LBM). Biomethane can be liquefied, creating a product known as liquefied biomethane (LBM). Two of the main advantages of LBM are that it can be transported relatively easily and it can be dispensed to either LNG vehicles or CNG vehicles. Liquid biomethane is transported in the same manner as LNG, that is, via insulated tanker trucks designed for transportation of cryogenic liquids.

Biomethane can be stored as CBM to save space. The gas is stored in steel cylinders such as those typically used for storage of other commercial gases. Storage facilities must be adequately fitted with safety devices such as rupture disks and pressure relief valves. The cost of compressing gas to high pressures between 2,000 and 5,000 psi is much greater than the cost of compressing gas for medium-pressure storage. Because of these high costs, the biogas is typically upgraded to biomethane prior to compression.

2011 in review – BioEnergy Consult Blog

The WordPress.com stats helper monkeys prepared a 2011 annual report for this blog.

Here’s an excerpt:

A San Francisco cable car holds 60 people. This blog was viewed about 2,800 times in 2011. If it were a cable car, it would take about 47 trips to carry that many people.

Click here to see the complete report.

Biogas Strorage

Image via Wikipedia

Selection of an appropriate biogas storage system makes a significant contribution to the efficiency and safety of a biogas plant. A biogas storage system also compensates fluctuations in the production and consumption of biogas as well as temperature-related changes in volume. There are two broad categories of biogas sto

rage systems: Internal Biogas Storage Tanks are integrated into the anaerobic digester while External Biogas Holders are separated from the digester forming autonomous components of a biogas plant.

The simplest and least expensive storage systems for on-site applications and intermediate storage of biogas are low-pressure systems. Floating gas holders on the digester form a low-pressure storage option for biogas systems. These systems typically operate at pressures below 2 psi. Floating gas holders can be made of steel, fiberglass, or a flexible fabric. A separate tank may be used with a floating gas holder for the storage of the digestate and also storage of the raw biogas. A major advantage of a digester with an integral gas storage component is the reduced capital cost of the system.

The least expensive and most trouble-free gas holder is the flexible inflatable fabric top, as it does not react with the H2S in the biogas and is integral to the digester. These types of covers are often used with plug-flow and complete-mix digesters. Flexible membrane materials commonly used for these gas holders include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low density polyethylene (LLDPE), and chlorosulfonated polyethylene covered polyester. Thicknesses for cover materials typically vary from 0.5 to 2.5 millimeters.

Trends in Food Waste Management

Food waste is an untapped energy source that mostly ends up rotting in landfills, thereby releasing greenhouse gases into the atmosphere. Food waste is difficult to treat or recycle since it contains high levels of sodium salt and moisture, and is mixed with other waste during collection. Major generators of food wastes include hotels, restaurants, supermarkets, residential blocks, cafeterias, airline caterers, food processing industries, etc.

In United States, food waste is the third largest waste stream after paper and yard waste. Around 12.7 percent of the total municipal solid waste (MSW) generated in the year 2008 was food scraps that amounted to about 32 million tons. According to EPA, about 31 million tons of food waste was thrown away into landfills or incinerators in 2008. As far as United Kingdom is concerned, households throw away 8.3 million tons of food each year. These statistics are an indication of tremendous amount of food waste generated all over the world.

The proportion of food waste in municipal waste stream is gradually increasing and hence a proper food waste management strategy needs to be devised to ensure its eco-friendly and sustainable disposal. Food waste can be recycled via:

• In-vessel composting (IVC): A treatment that breaks down biodegradable waste by naturally occurring micro-organisms with oxygen, in an enclosed vessel or tunnel;
• Anaerobic digestion (AD): A treatment that breaks down biodegradable waste in the absence of oxygen, producing a renewable energy (biogas) that can be used to generate electricity and heat.

Currently, only about 3 percent of food waste is recycled throughout U.S., mainly through composting. Composting provides an alternative to landfill disposal of food waste, however it requires large areas of land, produces volatile organic compounds and consumes energy. Consequently, there is an urgent need to explore better recycling alternatives. Anaerobic digestion has been successfully used in several European and Asian countries to stabilize food wastes, and to provide beneficial end-products. Sweden, Austria, Denmark, Germany and England have led the way in developing new advanced biogas technologies and setting up new projects for conversion of food waste into energy.

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. Food waste can either be used as a single substrate in a biogas plant, or can be co-digested with organic wastes like cow manure, poultry litter, sewage, crop residues, abattoir wastes, etc.

Global Waste-to-Energy Market

The global market for WTE technologies was valued at US$19.9bn in 2008. This has been forecasted to increase to US$26.2bn by 2014. While the biological WTE segment is expected to grow more rapidly from US$1.4bn in 2008 to approximately US$2.5bn in 2014, the thermal WTE segment is nonetheless estimated to still constitute the vast bulk of the entire industry’s worth. This segment was valued at US$18.5bn in 2008 and is forecasted to expand to US$23.7bn in 2014.

The global market for waste to energy technologies has shown substantial growth over the last five years, increasing from $4.83 billion in 2006, to $7.08 billion in 2010 with continued market growth through the global economic downturn. Over the coming decade, growth trends are expected to continue, led by expansion in the US, European, Chinese, and Indian markets. By 2021, based on continued growth in Asian markets combined with the maturation of European waste management regulations and European and US climate mitigation strategies, the annual global market for waste to energy technologies will exceed $27 billion, for all technologies combined.

Asia-Pacific’s waste-to-energy market will post substantial growth by 2015, as more countries view the technology as a sustainable alternative to landfills for disposing waste while generating clean energy. In its new report, Frost & Sullivan said the industry could grow at a compound annual rate of 6.7 percent for thermal waste-to-energy and 9.7 percent for biological waste-to-energy from 2008 to 2015.

The WTE market in Europe is forecasted to expand at an exponential rate and will continue to do so for at least the next 10 years. The continent’s WTE capacity is projected to increase by around 13 million tonnes, with almost 100 new WTE facilities to come online by 2012. In 2008, the WTE market in Europe consisted of approximately 250 players due in large to the use of bulky and expensive centralized WTE facilities, scattered throughout Western Europe.