05/06/2009 by David Slade.

Introduction

Biomass is feted to play one of the most important roles in reducing our reliance on fossil fuels, meeting the UK’s transport needs and providing the greatest contribution to Kyoto targets.

PPS 22 defines biomass as “the biodegradable fraction of products, wastes and residues from agriculture (including plant and animal substances), forestry and related industries, as well as the biodegradable fraction of industrial and municipal waste.”

Some examples of biomass use in the UK include:

• Power stations taking advantage of locally available biomass feedstocks such as straw, wood and chicken litter
• Farm slurry, sewage sludge and food waste being anaerobically digested to produce biogas for heat and electricity production
• Landfill gas being captured for power generation
• Housing developments and town regeneration projects making use of communal woodchip boilers
• Individual homes installing automated wood pellet and log boilers to provide most, if not all, of their space and hot water needs
• Waste vegetable oil and virgin rape oil undergoing trans-esterification for biodiesel production
• Bioethanol being produced from biomass by the hydrolysis and sugar fermentation processes, and then used as a renewable petrol substitute.

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29/05/2009 by David Slade.

Scientists at Queen’s University Belfast have discovered a new eco-friendly way of dissolving wood using ionic liquids that may help its transformation into popular products such as bio fuels, textiles, clothes and paper.

Dr Héctor Rodríguez and Professor Robin Rogers from Queen’s School of Chemistry and Chemical Engineering worked along with The University of Alabama, Tuscaloosa, AL, to come up with a more cost and energy efficient way of processing wood.

Their solution, which is reported in the journal Green Chemistry, may see a new sustainable future for industry based on bio-renewable resources. At present wood is broken down mainly by the Kraft pulping process, which originates from the 19th century and uses a wasteful technology relying on polluting chemicals.

The key reason for tolerating this method is that it is very difficult to break down and separate the different elements of wood. Until now any alternatives to the process have presented similar problems.

The Queen’s researchers found that chips of both softwood and hardwood dissolved completely in ionic liquid and only mild conditions of temperature and pressure were needed. By controlled addition of water and a water-acetone mixture, the dissolved wood was partially separated into a cellulose-rich material and pure lignin.

This process is much more environmentally-friendly than the current method as it uses less heat and pressure and produces very low toxicity while remaining biodegradable.

Professor Robin Rogers said: “This is a very important discovery because cellulose and lignin have a wide variety of uses. Cellulose can be used to make products such as paper, biofuels, cotton and linen, as well as many other commodity materials and chemicals.

“Lignin can be used to create performance additives in various applications, such as strengthening cars and airplanes with a fraction of the weight of conventional reinforcement materials. It is also a source of other chemicals which are mainly obtained from petroleum-based resources.”

Dr Héctor Rodríguez said: “The discovery is a significant step towards the development of the biorefinery concept, where biomass is transformed to produce a wide variety of chemicals. Eventually, this may open a door to a truly sustainable chemical industry based on bio-renewable resources.”

The approaches that the scientists are considering for the future include the addition of eco-friendly additives to the ionic liquid system or the use of catalysts.

The researchers are hoping to eventually achieve better dissolution under even softer conditions and are also trying to achieve complete separation of the different elements in one single step.

Both teams are also focusing on biomasses which are rich in essential oils and can later be used in processes such as the manufacture of fragrances.

The Journal reference for the study is:

Sun et al. Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate, Green Chemistry, 2009; 11 (5): 646 DOI: 10.1039/b822702k

Source: Science Daily .

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19/05/2009 by David Slade.

Byproducts of green plants used for other production purposes can be used as fuel, providing a source renewable energy.

Biomass residues are the organic byproducts of green plants used for things such as food, fiber and forest production.  Food industry residues include grain crops, for instance corn and wheat, as well as waste such as hazlenut shells and fruit stones. Other residues include animal waste and forest harvest; small trees and branches left after felling which can be made into wood chips.

These residues can all be used as a fuel source, fuelling a combined heat and power plant to produce an alternative source of energy to fossil fuels.

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