Palm kernel shells contain residues of Palm Oil, which accounts for its slightly higher heating value than average lignocellulosic biomass. Compared to other residues from the industry, it is a good quality biomass fuel with uniform size distribution, easy handling, easy crushing, and limited biological activity due to low moisture content. PKS can be readily co-fired with coal in grate fired -and fluidized bed boilers as well as cement kilns in order to diversify the fuel mix.

The primary use of palm kernel shells is as a boiler fuel supplementing the fibre which is used as primary fuel. In recent years kernel shells are sold as alternative fuel around the world. Besides selling shells in bulk, there are companies that produce fuel briquettes from shells which may include partial carbonisation of the material to improve the combustion characteristics.

As a raw material for fuel briquettes, palm shells are reported to have the same calorific characteristics as coconut shells. The relatively smaller size makes it easier to carbonise for mass production, and its resulting palm shell charcoal can be pressed into a heat efficient biomass briquette.

Palm kernel shells have been traditionally used as solid fuels for steam boilers in palm oil mills across Southeast Asia. The steam generated is used to run turbines for electricity production. These two solid fuels alone are able to generate more than enough energy to meet the energy demands of a palm oil mill. Most palm oil mills in the region are self-sufficient in terms of energy by making use of kernel shells and mesocarp fibers in cogeneration.

In recent years, the demand for palm kernel shells has increased considerably in Europe, Asia-Pacific, China etc. resulting in price close to that of coal. Nowadays, cement industries and power producers are increasingly using palm kernel shells to replace coal. In grate-fired boiler systems, fluidized-bed boiler systems and cement kilns, palm kernel shells are an excellent fuel.

Cofiring of PKS yields added value for power plants and cement kilns, because the fuel significantly reduces carbon emissions – this added value can be expressed in the form of renewable energy certificates, carbon credits, etc. However, there is a great scope for introduction of high-efficiency cogeneration systems in the industry which will result in substantial supply of excess power to the public grid and supply of surplus PKS to other nations. Palm kernel shell is already extensively in demand domestically by local industries for meeting process heating requirements, thus creating supply shortages in the market.

Palm oil mills around the world may seize an opportunity to supply electricity for its surrounding plantation areas using palm kernel shells, empty fruit branches and palm oil mill effluent which have not been fully exploited yet. This new business will be beneficial for all parties, increase the profitability and sustainability for palm oil industry, reduce greenhouse gas emissions and increase the electrification ratio in surrounding plantation regions.

The post The Energy Potential of Palm Kernel Shells first appeared on BioEnergy Consult.

Limitations of Bagasse

Bagasse is a ubiquitous primary fuel in cogeneration plants in sugar mills, which adds more than 2,000 MW of renewable power to the Indian energy mix. The inclination of cogeneration plant managers towards bagasse is primarily because of its virtue of being easily available on-site, and no requirement to purchase it from the external market.

This remains true despite its several significant shortcomings as a boiler fuel, prime among which are very high moisture content and low calorific value. As a result, the fuel-to-energy ratio remains abysmally low and the consequent lesser power generation is depriving these sugar mills from achieving true revenue potential from their ancillary power business vertical, which is pegged at ~10,000 MW.

Sugarcane Trash – A Wonder Waste

Though, there is a much neglected high calorific value biomass which is available in proximity of every sugar mill and is also a residue of the sugarcane crop itself, which could enable the cogeneration units to achieve their maximum output potential. This wonder waste is sugarcane trash – the dry leaves of sugarcane crop – which is left in the farms itself after sugarcane harvesting as it has no utility as fodder and generally burnt by farmers, which harms the surrounding air quality substantially.

Given its favourable properties of having very low moisture content with moderate-to-high calorific value, sugarcane trash could be used in most of the high pressure boiler designs in a considerable proportion along with bagasse.

Undeniably, sugar mills should not discontinue using bagasse as the primary fuel, but surely complement it with sugarcane trash as it would lead to an increase in their revenue generation and would also allow them to expand operations of their cogeneration plant to off-season, as using sugarcane trash with bagasse in season would leave more bagasse for off-season usage.

Hurdles to Overcome

Despite these evident benefits, the major obstacle in development of sugarcane trash as an industrial boiler fuel has been its difficult collection from thousands of small and fragmented farms. Moreover, the trash becomes available and needs to be collected simultaneously during the operating season of the sugar mills, which makes deployment of resources, human or otherwise, for managing the procurement of trash very difficult for any sugar mill.

As a matter of fact, the sugar mills which initiated the pilots, or even scaled commercially, to utilise sugarcane trash along with bagasse, had to sooner or later discontinue its use, owing to the mammoth challenges discussed above.

The Way Forward

Thus, in order to utilise this wonder waste, there is a dire need to outsource its procurement to professional and organised players which establish the biomass supply chain infrastructure in the vicinity of the cogeneration units to make on-site availability of sugarcane trash as convenient as bagasse and enable them to procure the rich quality biomass at sustainable prices which leads to an increase in their profits.

These biomass supply chain companies offer value to the farmers by processing their crop residues in timely manner, thus prevent open burning of the crop residue and contribute to a greener and cleaner environment.

Indeed, owing to its favourable fuel properties, positive environmental impact and now, with ease in its procurement, sugarcane trash is the renewable fuel of today and future for the Indian sugar mills.

The post Sugarcane Trash – A Renewable Fuel of Today and Future first appeared on BioEnergy Consult.

The design and equipment choice for the fuel handling system, including preparation and refinement systems is carried out in accordance with the plant configuration. This is of special importance when the biomass is not homogeneous and contains impurities, typically for forest and agricultural wastes. Some of the common problems encountered have been the unpopular design and undersized fuel handling, preparation and feeding systems.

The fuel handling core systems and equipment are dependent on both the raw fuel type and condition as well as on the conversion/combustion technology employed. The core equipment in a biomass power plant include the following:

1. Fuel reception
2. Fuel weighing systems
3. Receiving bunkers
4. Bunker discharge systems (stoker, screw, grab bucket)
5. Fuel preparation
6. Fuel drying systems
7. Crushers
8. Chippers
9. Screening systems
10. Shredding systems
11. Grinding systems (for pulverised fuel burners)
12. Safety systems (explosion relieve, emergency discharge, fire detections etc)
13. Fuel transport and feeding
14. Push floors
15. Belt feeders
16. Conveyers and Elevators
17. Tube feeders
18. Fuel hoppers and silos (refined fuel)
19. Hopper, bunker and silo discharge
20. Feeding stokers
21. Feeding screws
22. Rotary valves

To enable any available biomass resource to be matched with the end use energy carrier required (heat, electricity or transport fuels) the correct selection of conversion technologies is required. Since the forms in which biomass can be used for energy are diverse, optimal resources, technologies and entire systems will be shaped by local conditions, both physical and socio-economic in nature.

As the majority of people in developing countries will continue using biomass as their primary energy source well into the next century, it is of critical importance that biomass-based energy truly can be modernized to yield multiple socioeconomic and environmental benefits.

The post Overview of Biomass Handling Equipment first appeared on BioEnergy Consult.

Biomass pelletization is a standard method for the production of high density, solid energy carriers from biomass. Pellets are manufactured in several types and grades as fuels for electric power plants, homes, and other applications. Pellet-making equipment is available at a variety of sizes and scales, which allows manufacture at domestic as well industrial-scale production. Pellets have a cylindrical shape and are about 6-25 mm in diameter and 3-50 mm in length. There are European standards for biomass pellets and raw material classification (EN 14961-1, EN 14961-2 and EN 14961-6) and international ISO standards under development (ISO/DIS 17225-1, ISO/DIS 17225-2 and ISO/DIS 17225-6).

Process Description

The biomass pelletization process consists of multiple steps including raw material pre-treatment, pelletization and post-treatment. The first step in the pelletization process is the preparation of feedstock which includes selecting a feedstock suitable for this process, its filtration, storage and protection. Raw materials used are sawdust, wood shavings, wood wastes, agricultural residues like straw, switchgrass etc. Filtration is done to remove unwanted materials like stone, metal, etc. The feedstock should be stored in such a manner that it is away from impurities and moisture. In cases where there are different types of feedstock, a blending process is used to achieve consistency.

The moisture content in biomass can be considerably high and are usually up to 50% – 60% which should be reduced to 10 to 15%. Rotary drum dryer is the most common equipment used for this purpose. Superheated steam dryers, flash dryers, spouted bed dryers and belt dryers can also be used. Drying increases the efficiency of biomass and it produces almost no smoke on combustion. It should be noted that the feedstock should not be over dried, as a small amount of moisture helps in binding the biomass particles. The drying process is the most energy intensive process and accounts for about 70% of the total energy used in the pelletization process.

Before feeding biomass to pellet mills, the biomass should be reduced to small particles of the order of not more than 3mm. If the pellet size is too large or too small, it affects the quality of pellet and in turn increases the energy consumption. Therefore the particles should have proper size and should be consistent. Size reduction is done by grinding using a hammer mill equipped with a screen of size 3.2 to 6.4 mm. If the feedstock is quite large, it goes through a chipper before grinding.

The next and the most important step is pelletization where biomass is compressed against a heated metal plate (known as die) using a roller. The die consists of holes of fixed diameter through which the biomass passes under high pressure. Due to the high pressure, frictional forces increase, leading to a considerable rise in temperature. High temperature causes the lignin and resins present in biomass to soften which acts as a binding agent between the biomass fibers. This way the biomass particles fuse to form pellets.

The rate of production and electrical energy used in the pelletization of biomass are strongly correlated to the raw material type and processing conditions such as moisture content and feed size. The The average energy required to pelletize biomass is roughly between 16 kWh/t and 49kWh/t. During pelletization, a large fraction of the process energy is used to make the biomass flow into the inlets of the press channels.

Binders or lubricants may be added in some cases to produce higher quality pellets. Binders increase the pellet density and durability. Wood contains natural resins which act as a binder. Similarly, sawdust contains lignin which holds the pellet together. However, agricultural residues do not contain much resins or lignin, and so a stabilizing agent needs to be added in this case. Distillers dry grains or potato starch is some commonly used binders. The use of natural additives depends on biomass composition and the mass proportion between cellulose, hemicelluloses, lignin and inorganics.

Due to the friction generated in the die, excess heat is developed. Thus, the pellets are very soft and hot (about 70 to 90^oC). It needs to be cooled and dried before its storage or packaging. The pellets may then be passed through a vibrating screen to remove fine materials. This ensures that the fuel source is clean and dust free.

The pellets are packed into bags using an overhead hopper and a conveyor belt. Pellets are stored in elevated storage bins or ground level silos. The packaging should be such that the pellets are protected from moisture and pollutants. Commercial pellet mills and other pelletizing equipment are widely available across the globe.

The post Biomass Pelletization Process first appeared on BioEnergy Consult.

Several recent studies have pointed out that biofuel from microalgae has the potential to become a renewable, cost-effective alternative for fossil fuel with reduced impact on the environment and the world supply of staple foods, such as wheat, maize and sugar.

What are Algae?

Algae are unicellular microorganisms, capable of photosynthesis. They are one of the world’s oldest forms of life, and it is strongly believed that fossil oil was largely formed by ancient microalgae. Microalgae (or microscopic algae) are considered as a potential oleo-feedstock, as they produce lipids through photosynthesis, i.e. using only carbon, water, sunlight, phosphates, nitrates and other (oligo) elements that can be found in residual waters.

Oils produced by diverse algae strains range in composition. For the most part are like vegetable oils, though some are chemically similar to the hydrocarbons in petroleum.

Advantages of Algae

Apart from lipids, algae also produce proteins, isoprenoids and polysaccharides. Some strains of algae ferment sugars to produce alcohols, under the right growing conditions. Their biomass can be processed to different sorts of chemicals and polymers (Polysaccharides, enzymes, pigments and minerals), biofuels (e.g. biodiesel, alkanes and alcohols), food and animal feed (PUFA, vitamins, etc.) as well as bioactive compounds (antibiotics, antioxidant and metabolites) through down-processing technology such as transesterification, pyrolysis and continuous catalysis using microspheres.

Algae can be grown on non-arable land (including deserts), most of them do not require fresh water, and their nutritional value is high. Extensive R&D is underway on algae as raw material worldwide, especially in North America and Europe with a high number of start-up companies developing different options.

Most scientific literature suggests an oil production potential of around 25-50 ton per hectare per year for relevant algae species. Microalgae contain, amongst other biochemical, neutral lipids (tri-, di-, monoglycerides free fatty acids), polar lipids (glycolipids, phospholipids), wax esters, sterols and pigments. The total lipid content in microalgae varies from 1 to 90 % of dry weight, depending on species, strain and growth conditions.

What is Algae Biorefinery

In order to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, carbohydrates) should be used and therefore biorefining of microalgae is very important for the selective separation and use of the functional biomass components.

The term algae biorefinery was coined to describe the production of a wide range of chemicals and biofuels from algal biomass by the integration of bio-processing and appropriate low environmental impact chemical technologies in a cost-effective and environmentally sustainable.

If biorefining of microalgae is applied, lipids should be fractionated into lipids for biodiesel, lipids as a feedstock for the chemical industry and essential fatty acids, proteins and carbohydrates for food, feed and bulk chemicals, and the oxygen produced can be recovered as well.

The potential for commercial algae production, also known as algaculture, is expected to come from growth in translucent tubes or containers called photo bioreactors or in open systems (e.g. raceways) particularly for industrial mass cultivation or more recently through a hybrid approach combining closed-system pre-cultivation with a subsequent open-system.

Advantages of Algae Biorefinery

The major advantages of an algae biorefinery include:

• Use of industrial refusals as inputs ( CO₂,wastewater and desalination plant rejects)
• Large product basket with energy-derived (biodiesel, methane, ethanol and hydrogen) and non-energy derived (nutraceutical, fertilizers, animal feed and other bulk chemicals) products.
• Not competing with food production (non-arable land and no freshwater requirements)
• Better growth yield and lipid content than crops.

Indeed, after oil extraction the resulting algal biomass can be processed into ethanol, methane, livestock feed, used as organic fertilizer due to its high N:P ratio, or simply burned for energy cogeneration (electricity and heat). If, in addition, production of algae is done on residual nutrient feedstock and CO₂, and production of microalgae is done on large scale in order to lower production costs, production of bulk chemicals and fuels from microalgae will become economically, environmentally and ethically extremely attractive.

The post Everything You Should Know About An Algae Biorefinery first appeared on BioEnergy Consult.

Another option is to transfer the biomass to a central location where the material is accumulated and subsequently dispatched to the energy conversion facility. While in depot, the biomass could be pre-processed minimally (ground) or extensively (pelletized). The depot also provides an opportunity to interface with rail transport if that is an available option. The choice of any of the options depends on the economics and cultural practices. For example in irrigated areas, there is always space on the farm (corner of the land) where quantities of biomass can be stacked.

The key components to reduce costs in harvesting, collecting and transportation of biomass can be summarized as:

• Reduce the number of passes through the field by amalgamating collection operations.
• Increase the bulk density of biomass
• Work with minimal moisture content.
• Granulation/pelletization is the best option, though the existing technology is expensive.
• Trucking seems to be the most common mode of biomass transportation option but rail and pipeline may become attractive once the capital costs for these transport modes are reduced.

The logistics of transporting, handling and storing the bulky and variable biomass material for delivery to the biopower plant is a key part of the biomass supply chain that is often overlooked by project developers. Whether the biomass comes from forest residues on hill country, straw residues from cereal crops grown on arable land, or the non-edible components of small scale, subsistence farming systems, the relative cost of collection will be considerable.

Careful development of a system to minimize machinery use, human effort and energy inputs can have a considerable impact on the cost of the biomass as delivered to the biomass processing plant gate.

Most of the agricultural biomass resources tend to have a relatively low energy density compared with fossil fuels. This often makes handling, storage and transportation more costly per unit of energy carried. Some crop residues are often not competitive because the biomass resource is dispersed over large areas leading to high collection and transport costs.

The costs for long distance haulage of bulky biomass will be minimized if the biomass can be sourced from a location where it is already concentrated, such as sugar mill. It can then be converted in the nearby biomass energy plant to more transportable forms of energy carrier if not to be utilized on-site.

The logistics of supplying a biopower plant with sufficient volumes of biomass from a number of sources at suitable quality specifications and possibly all year round, are complex. Agricultural residues can be stored on the farm until needed. Then they can be collected and delivered directly to the conversion plant on demand. At times this requires considerable logistics to ensure only a few days of supply are available on-site but that the risk of non-supply at any time is low.

Losses of dry matter, and hence of energy content, commonly occur during the harvest transport and storage process. This can either be from physical losses of the biomass material in the field during the harvest operation or dropping off a truck, or by the reduction of dry matter of biomass material which occurs in storage over time as a result of respiration processes and as the product deteriorates. Dry matter loss is normally reduced over time if the moisture content of the biomass can be lowered or oxygen can be excluded in order to constrain pathological action.

To ensure sufficient and consistent biomass supplies, all agents involved with the production, collection, storage, and transportation of biomass require compensation for their share of costs incurred. In addition, a viable biomass production and distribution system must include producer incentives, encouraging them to sell their post-harvest plant residue.

The post The Logistics of a Biomass Power Plant first appeared on BioEnergy Consult.

Biochar holds the promise to tackle chronic human development issues like hunger and food insecurity, low agricultural productivity and soil depletion, deforestation and biodiversity loss, energy poverty, water pollution, air pollution and climate change. Let us have a close look at some of the most promising applications of biochar.

1. Use of biochar in animal farming

At present approx. 90% of the biochar used in Europe goes into animal farming. Different to its application to fields, a farmer will notice its effects within a few days. Whether used in feeding, litter or in slurry treatment, a farmer will quickly notice less smell. Used as a feed supplement, the incidence of diarrhoea rapidly decreases, feed intake is improved, allergies disappear, and the animals become calmer.

In Germany, researchers conducted a controlled experiment in a dairy that was experiencing a number of common health problems: reduced performance, movement disorder, fertility disorders, inflammation of the urinary bladder, viscous salivas, and diarrhoea. Animals were fed different combinations of charcoal, sauerkraut juice or humic acids over periods of 4 to 6 weeks.

Experimenters found that oral application of charcoal (from 200 to 400 g/day), sauerkraut juice and humic acids influenced the antibody levels to C. botulinum, indicating reduced gastrointestinal neurotoxin burden. They found that when the feed supplements were ended, antibody levels increased, indicating that regular feeding of charcoal and other supplements had a tonic effect on cow health.

2. Biochar as soil conditioner

In certain poor soils (mainly in the tropics), positive effects on soil fertility were seen when applying untreated biochar. These include the higher capacity of the soil to store water, aeration of the soil and the release of nutrients through raising the soil’s pH value. In temperate climates, soils tend to have humus content of over 1.5%, meaning that such effects only play a secondary role.

Indeed, fresh biochar may adsorb nutrients in the soil, causing at least in the short and medium term – a negative effect on plant growth. These are the reasons why in temperate climates biochar should only be used when first loaded with nutrients and when the char surfaces have been activated through microbial oxidation.

The best method of loading nutrients is to co-compost the char. This involves adding 10–30% biochar (by volume) to the biomass to be composted. Co-composting improves both the biochar and the compost. The resulting compost can be used as a highly efficient substitute for peat in potting soil, greenhouses, nurseries and other special cultures.

Because biochar serves as a carrier for plant nutrients, it can produce organic carbon-based fertilizers by mixing biochar with such organic waste as wool, molasses, ash, slurry and pomace. These are at least as efficient as conventional fertilizers, and have the advantage of not having the well-known adverse effects on the ecosystem. Such fertilizers prevent the leaching of nutrients, a negative aspect of conventional fertilizers. The nutrients are available as and when the plants need them. Through the stimulation of microbial symbiosis, the plant takes up the nutrients stored in the porous carbon structure and on its surfaces.

A range of organic chemicals are produced during pyrolysis. Some of these remain stuck to the pores and surfaces of the biochar and may have a role in stimulating a plant’s internal immune system, thereby increasing its resistance to pathogens. The effect on plant defence mechanisms was mainly observed when using low temperature biochars (pyrolysed at 350° to 450°C). This potential use is, however, only just now being developed and still requires a lot of research effort.

3. Biochar as construction material

The two interesting properties of biochar are its extremely low thermal conductivity and its ability to absorb water up to 6 times its weight. These properties mean that biochar is just the right material for insulating buildings and regulating humidity. In combination with clay, but also with lime and cement mortar, biochar can be added to clay at a ratio of up to 50% and replace sand in lime and cement mortars. This creates indoor plasters with excellent insulation and breathing properties, able to maintain humidity levels in a room at 45–70% in both summer and winter. This in turn prevents not just dry air, which can lead to respiratory disorders and allergies, but also dampness and air condensing on the walls, which can lead to mould developing.

As per study by the Ithaka Institute’s biochar-plaster wine cellar and seminar rooms in the Ithaka Journal. Such biochar-mud plaster adsorbs smells and toxins, a property not just benefiting smokers. Biochar-mud plasters can improve working conditions in libraries, schools, warehouses, factories and agricultural buildings.

Biochar is an efficient adsorber of electromagnetic radiation, meaning that biochar-mud plaster can prevent “electrosmog”. Biochar can also be applied to the outside walls of a building by jet-spray technique mixing it with lime. Applied at thicknesses of up to 20 cm, it is a substitute for Styrofoam insulation. Houses insulated this way become carbon sinks, while at the same time having a more healthy indoor climate. Should such a house be demolished at a later date, the biochar-mud or biochar-lime plaster can be recycled as a valuable compost additive.

4. Biochar as decontaminant

As a soil additive for soil remediation – for use in particular on former mine-works, military bases and landfill sites.

Soil substrates – Highly adsorbing and effective for plantation soil substrates for use in cleaning wastewater; in particular urban wastewater contaminated by heavy metals.

A barrier preventing pesticides getting into surface water – berms around fields and ponds can be equipped with 30-50 cm deep barriers made of biochar for filtering out pesticides.

Treating pond and lake water – biochar is good for adsorbing pesticides and fertilizers, as well as for improving water aeration.

5. Use of biochar in wastewater treatment – Our Project

The biochar grounded to a particle size of less than 1.5 mm and surface area of 600 – 1000 m²/g. The figure below is the basic representation of production of biochar for wastewater treatment.

We conducted a study for municipal wastewater which was obtained from a local municipal treatment plant. The municipal wastewater was tested for its physicochemical parameters including pH, chemical oxygen demand (COD), total suspended solids (TSS), total phosphates (TP) and total Kjeldahl nitrogen (TKN) using the APHA (2005) standard methods.

Bio filtration of the municipal wastewater with biochar acting as the bio adsorbent was allowed to take place over a 5 day period noting the changes in the wastewater parameters. The municipal wastewater and the treated effluent physicochemical.

The COD concentration in the municipal wastewater decreased by 90% upon treatment with bio-char. The decrease in the COD was attributed to the enhanced removal of bio contaminants as they were passed through the biochar due to the biochar’s adsorption properties as well as the high surface area of the bio char. An 89% reduction in the TSS was observed as the bio filtration process with bio char increased from one day to five days

The TKN concentration in the wastewater decreased by 64% upon treatment with bio char as a bio filter. The TP in the wastewater decreased by 78% as the bio filtration time with biochar increase. The wastewater pH changed from being alkaline to neutral during the treatment with biochar over the 5 day period

6. Use of Biochar in Textiles

In Japan and China bamboo-based biochar are already being woven into textiles to gain better thermal and breathing properties and to reduce the development of odours through sweat. The same aim is pursued through the inclusion of biochar in shoe soles and socks.

The post Things You Should Know About the Different Uses of Biochar first appeared on BioEnergy Consult.

Biomass wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels.If you are writing an essay related to this topic experts from the best custom essay service in usa advise you to read and analyze the information provided in this article.

Anaerobic Digestion

Anaerobic digestion is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas. Anaerobic digestion is a reliable technology for the treatment of wet, organic waste. Organic waste from various sources is biochemically degraded in highly controlled, oxygen-free conditions circumstances resulting in the production of biogas which can be used to produce both electricity and heat. Biomass conversion technologies are slowing being built for home boilers also.

The team over at The Solar Advantage says this, ‘”Almost any organic material can be processed with anaerobic digestion. This includes biodegradable waste materials such as municipal solid waste, animal manure, poultry litter, food wastes, sewage and industrial wastes.”

An anaerobic digestion plant produces two outputs, biogas and digestate, both can be further processed or utilized to produce secondary outputs. Biogas can be used for producing electricity and heat, as a natural gas substitute and also a transportation fuel. A combined heat and power plant system (CHP) not only generates power but also produces heat for in-house requirements to maintain desired temperature level in the digester during cold season. In Sweden, the compressed biogas is used as a transportation fuel for cars and buses. Biogas can also be upgraded and used in gas supply networks.

Digestate can be further processed to produce liquor and a fibrous material. The fiber, which can be processed into compost, is a bulky material with low levels of nutrients and can be used as a soil conditioner or a low level fertilizer. A high proportion of the nutrients remain in the liquor, which can be used as a liquid fertilizer. Many companies are use R&D tax credits to carry out these initiatives.

Biofuel Production

A variety of fuels can be produced from waste resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues. Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking, apart from powering boilers.

The largest potential feedstock for ethanol is lignocellulosic biomass wastes, which includes materials such as agricultural residues (corn stover, crop straws and bagasse), herbaceous crops (alfalfa, switchgrass), short rotation woody crops, forestry residues, waste paper and other wastes (municipal and industrial). Bioethanol production from these feedstocks could be an attractive alternative for disposal of these residues. Importantly, lignocellulosic feedstocks do not interfere with food security.

Ethanol from lignocellulosic biomass is produced mainly via biochemical routes. The three major steps involved are pretreatment, enzymatic hydrolysis, and fermentation. Biomass is pretreated to improve the accessibility of enzymes. After pretreatment, biomass undergoes enzymatic hydrolysis for conversion of polysaccharides into monomer sugars, such as glucose and xylose. Subsequently, sugars are fermented to ethanol by the use of different microorganisms.

Best Cordless Finish Nailer

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Sugar factories in Mauritius produce about 600,000 tons of sugar from around 5.8 million tons of sugarcane which is cultivated on an agricultural area of about 72,000 hectares. Of the total sugarcane production, around 35 percent is contributed by nearly 30,000 small growers. There are more than 11 sugar factories presently operating in Mauritius having crushing capacities ranging from 75 to 310 tons cane per hour.

During the sugar extraction process, about 1.8 million tons of Bagasse is produced as a by-product, or about one third of the sugarcane weight. Traditionally, 50 percent of the dry matter is harvested as cane stalk to recover the sugar with the fibrous fraction, i.e. Bagasse being burned to power the process in cogeneration plant. Most factories in Mauritius have been upgraded and now export electricity to the grid during crop season, with some using coal to extend production during the intercrop season.

Surplus electricity is generated in almost all the sugar mills. The total installed capacity within the sugar industry is 243 MW out of which 140 MW is from firm power producers. Around 1.6 – 1.8 million tons of bagasse (wet basis) is generated on an annually renewable basis and an average of around 60 kWh per ton sugarcane is generated for the grid throughout the island.

The surplus exportable electricity in Mauritian power plants has been based on a fibre content ranging from 13- 16% of sugarcane, 48% moisture content in Bagasse, process steam consumption of 350–450 kg steam per ton sugarcane and a power consumption of 27-32 kWh per ton sugarcane.

In Mauritius, the sugarcane industry is gradually increasing its competitiveness in electricity generation. It has revamped its boiler houses by installing high pressure boilers and condensing extraction steam turbine. All the power plants are privately owned, and the programme has been a landmark to show how all the stakeholders (government, corporate and small planters) can co-operate. The approach is being recommended to other sugarcane producing countries worldwide to harness the untapped renewable energy potential of biomass wastes from the sugar industry.

The post Salient Features of Sugar Industry in Mauritius first appeared on BioEnergy Consult.

Biomass gasification provides a means of deriving more diverse forms of energy from the thermochemical conversion of biomass than conventional combustion. The basic gasification process involves devolatization, combustion and reduction.

During devolatization, methane and other hydrocarbons are produced from the biomass by the action of heat which leaves a reactive char.

During combustion, the volatiles and char are partially burned in air or oxygen to generate heat and carbon dioxide. In the reduction phase, carbon dioxide absorbs heat and reacts with the remaining char to produce carbon monoxide (producer gas). The presence of water vapour in a gasifier results in the production of hydrogen as a secondary fuel component.

There are two main types of gasifier that can be used to carry out this conversion, fixed bed gasifiers and fluidized bed gasifiers. The conversion of biomass into a combustible gas involves a two-stage process. The first, which is called pyrolysis, takes place below 600°C, when volatile components contained within the biomass are released. These may include organic compounds, hydrogen, carbon monoxide, tars and water vapour.

Pyrolysis leaves a solid residue called char. In the second stage of the gasification process, this char is reacted with steam or burnt in a restricted quantity of air or oxygen to produce further combustible gas. Depending on the precise design of gasifier chosen, the product gas may have a heating value of 6 – 19 MJ/Nm³.

The products of gasification are a mixture of carbon monoxide, carbon dioxide, methane, hydrogen and various hydrocarbons, which can then be used directly in gas turbines, and boilers, or used as precursors for synthesising a wide range of other chemicals.

In addition there are a number of methods that can be used to produce higher quality product gases, including indirect heating, oxygen blowing, and pressurisation. After appropriate treatment, the resulting gases can be burned directly for cooking or heat supply, or used in secondary conversion devices, such as internal combustion engines or gas turbines, for producing electricity or shaft power (where it also has the potential for CHP applications).

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