How is biomass recovered

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That said, some waste residues generated from crops such as sugarcane, rice, ground- and coffee nuts are used as a fuel source. Thus, as only a small amount of the biomass waste generated becomes a feedstock for industrial applications and electricity generation, the remaining adversely impacts the atmosphere, surface and ground-water quality and causes pestilence.

Of the huge quantities of annual global generation of agricultural residue, 8 , 9 cereal crops are a major contributor. It should be noted that some of these have potential use in energy production. Table 1. Currently, the global resource for unexploited cereal crop residues is ca. Global cereal yield is predicted to increase in the range of 0.

Of increasing importance is the use of oil crops, which have grown by 2. The other sector of interest is forestry, which generates woody biomass residues from timber logging. There is a further 1 B ha of wooded land worldwide. The global production of wood-derived biomass is around 4. Industrial wood from forest felling and sawmill residues for these countries is shown in Table 3. The increasing production of agricultural biomass waste also poses risks to human health.

Unregulated land disposal pollutes surface and ground waters, inducing eutrophication, and when incorporated into soil, biomass-induced microflora stimulate the production and emission of greenhouse gases GHG NO and N 2 O, which have considerably greater global warming potential than CO 2. Notwithstanding, the complex environmental impacts, including the positive e.

For example, open fires and low-efficiency stoves are traditionally used in developing countries, and result in poor indoor air quality. As developing energy policy recognises the need to reduce coal use, renewable energy and the sustainable use of biomass resources is of increasing importance IEA — As indicated, the major developments in the reuse of biomass residues over the past 25 years are primarily concentrated in the bioenergy sector, although use in specialist product development, alternative fuels and biochar production has also increased.

The European Biomass Association reported the consumption of In the USA, the bulk of the agricultural residues — Mt is used by industry. Until recently, agricultural wastes were managed by burning or landfill, but now in many states e. In Europe, straw is the main agricultural crop feedstock for bioenergy following a ban on field burning. However, the impact of using straw for energy production has important implications for a reduction in the supply of organic matter to agricultural soils.

In a number of African countries, the use of sugar bagasse to generate heat and electricity is increasing. Many countries do seek to avoid biomass waste disposal through resource recovery and utilisation, and we have seen the increased use of wood residues for energy generation. However, incineration and pyrolysis generate substantial amounts of ash that requires management.

The commitment of industrialised countries to reduce atmospheric CO 2 emissions through carbon Capture and Storage initiatives is well known, but the ability to deliver is lacking due to cost and technology readiness. Recent technological developments have created opportunities for carbon dioxide utilisation CCU , where CO 2 is used as a feedstock that is transformed to produce a range of materials including construction materials, plastics and fuels.

It should be noted that the intentional use of CO 2 to condition cementitious materials has been practiced for decades, including for the rapid hardening of calcium silicate-based materials 69 and concrete articles, such as roofing tiles. Building on our previous endeavours, therefore, the carbonation of biomass ash is the primary focus of the present work. The Gt quantities of biomass residues, generated yearly, are not managed sustainably. The EU Waste Framework Directive requires action to minimise waste, reduce reliance on landfill and increase recycling.

This becomes more important when the wastes could be utilised to reduce the high pressure on the virgin material resources e. Our interest in CO 2 is in the manufacture of value-added products utilising solid wastes. The IEA projected that in , both agricultural and forest residues will be increased globally to 6. The use of biomass residues in cement-bound composites comprising Portland cement, fly ash and blast furnace slag to manufacture building materials is practiced in several parts of the world.

Furthermore, the effects of lime crystallisation and the dissolution of cellulose, hemicellulose and certain lignins also contribute to denaturing of these additives. The use of a low-carbon engineering approach to biomass wastes including their ashes can involve captured gaseous CO 2 to produce construction materials.

In utilising CO 2 directly from point sources and locking it up in the built environment, high volumes of waste and CO 2 could be stored in manufactured products as mineral carbonates. Described by Bertos et al.

Table 4 lists industrial waste streams with potential to be used as feedstock with gasesous carbon dioxide in the manufacture of low-carbon materials. The biomass ashes, derived from fruit peel, crop fibre, nut shells and wood waste, are often reactive to CO 2 and can be valorised via a managed carbonation step as construction products.

The ash generated from biomass-based power plants can be combined with the point-source CO 2 captured directly from the incineration process into sustainable, carbon-negative construction materials. Waste to energy plants emits 47 Mt CO 2 each year, 58 and as the ashes generated tend to be reactive to CO 2 to a lesser or greater degree, there is potential to mineralise these ashes to manufacture value-added products.

In Europe, biomass waste arising from straw and other cereal and oil crops is projected to be Mt by The environmental and economic perspectives of the biomass utilisation, by using a CCU approach as described, are given in Fig. Environmental and economic perspectives of biomass waste valorisation by using a CCU-based approach.

The on-site, i. The ashes arising were analysed, and their potential to react with CO 2 gas was assessed Table 5. As can be seen, the different ashes combine with significant amounts of mineralised CO 2.

The results reflect the difference in chemistry and mineralogy of the ashes. The biomass residues studied in this work were sourced in India, Africa and the UK.

The resulting ashes were then examined for selected physical properties e. The dry-carbonation method employed has been directly correlated with the CO 2 uptake achieved in commercial carbonation facilities operating in the UK. The strength of these monolithic products is a reflection of how well carbonate-cemented they are.

Compressive strength was obtained by applying a force until the cylinders failed by using Eq. The original findings of this particular work have been communicated separately. The available residues from European cereal and oil crops are projected to rise to Mt by Their ashed residues have potential to mineralise 1. On a global scale, the projections for indicate an increase in demand for all biomass wastes, with a larger proportion of agricultural residues being used for energy production.

Biomass fibres are used for making light-weight concretes 96 bound by Portland cement and lime-based binders, which are directly associated with CO 2 emissions [e. As our work has shown that biomass ash can be used as a substitute for hydraulic cement, or be used as a carbonateable medium in its own right, there are important implications for the use of ash in bound products. Not least, the cold-processing route described has a low-energy intensity, which is unlike that of the firing, sintering or bloating processes employed in the production of bricks or manufactured aggregates.

With reference to Fig. For clarity, we are not concerned with the ability of ashes to act as a pozzolan, but as a ready source of CaO that can form calcium silicate hydrate. If the ashes contain reactive silica, which some do, then there are further possible advantages in terms of strength and durability.

Either way—whether an addition to a hydraulically- or a carbonate-bound system, the careful use of selected ashes could significantly lower the embodied carbon of construction materials employing a blended PC-biomass ash binder.

The available crop residues on a global scale are considerable as a number of modelling studies suggest that those currently available from agriculture including for energy are 2. Countries paying higher landfill gate fees and for the waste to energy already have an incentive to valorise waste otherwise destined for final disposal.

As biomass residues are increasingly burnt in power plants to produce energy, it has been shown that their ashes and point-source CO 2 can be combined in the manufacture of carbonated products.

This circular management strategy has potential to preserve landfill space, increase the resources available for construction and reduce CO 2 emissions, and environmental harms. As not all biomass ash residues are suitable for direct processing by carbonation, our experience is that many are readily carbonateable due to their facilitating mineral content.

Therefore, by the careful mixing of biomass ashes and raw wastes, carbonate-cemented composite products can be manufactured; findings will be reported fully elsewhere. In developing countries where biomass residues are available in quantity, 99 and development goals are driving rapid urbanisation, new products with potential to replace virgin materials may have wide benefits. The data that support the findings of this study are available from the corresponding authors upon reasonable request.

Subject to IP considerations, this ongoing work develops a database that will be developed and made available. Chun, A. Global forest products facts and figures.

Schieber, A. By-products of plant food processing as a source of functional compounds-Recent developments. Trends Food Sci. Article Google Scholar. Yevich, R. An assessment of biofuel use and burning of agricultural waste in the developing world. Cycles 17 , Khedari, J. New insulating particle boards from durian peel and coconut coir.

Where most people see a costly mess in the million tons of trash Americans discard each year, CleanTech Biofuels sees more than million tons of cellulosic material that can be converted into valuable energy products. CleanTech Biofuels has a unique feedstock solution that taps into an abundant alternative-energy source while solving environmental and social problems at the same time.

According to the EPA , Americans produce about million tons of garbage each year. There is tremendous energy stored in all of that garbage, which is lost forever in traditional landfill operations.

As a result, most existing facilities had to be retrofitted with air pollution control systems or shut down. Currently, there are 75 facilities in the United States that recover energy from the combustion of municipal solid waste. These facilities exist in 25 states, mainly in the Northeast. A new facility was built in Palm Beach County, Florida in A typical waste to energy plant generates about kilowatt hours kWh of energy per ton of waste.

At an average price of four cents per kWh, revenues per ton of solid waste are often 20 to 30 dollars. MSW combustion accounts for a small portion of American waste management for multiple reasons. Generally speaking, regions of the world where populations are dense and land is limited e.

As the United States encompasses a large amount of land, space limitations have not been as important a factor in the adoption of combustion with energy recovery.

Landfilling in the United States is often considered a more viable option, especially in the short term, due to the low economic cost of building an MSW landfill verses an MSW combustion facility. Another factor in the slow growth rate of MSW combustion in the United States is public opposition to the facilities.

These facilities have not always had air emission control equipment, thus gaining a reputation as high polluting. In addition, many communities do not want the increased traffic from trucks or to be adjacent to any facility handling municipal waste. Additionally, the upfront money needed to build an MSW combustion facility can be significant and economic benefits may take several years to be fully realized.

A new plant typically requires at least million dollars to finance the construction; larger plants may require double to triple that amount. MSW Combustion facilities typically collect a tipping fee from the independent contractors that drop the waste off on a daily basis to recover costs. The facilities also receive income from utilities after the electricity generated from the waste is sold to the grid.

A possible third stream of revenue for the facilities comes from the sale of both ferrous iron and non-ferrous scrap metal collected from the post-combusted ash stream. The amount of ash generated ranges from percent by weight and from percent by volume of the MSW processed.

Generally, MSW combustion residues consist of two types of material: fly ash and bottom ash. Fly ash refers to the fine particles that are removed from the flue gas and includes residues from other air pollution control devices, such as scrubbers.