Biomass to Chemicals

Agriculture Waste

Economic part of agricultural activity is ‘‘the yield’’ and the less important part of it is used to be called ‘‘ agriculture waste’’

Agricultural waste in developing countries is about 35 percent of agricultural crop products annually and could be a potential source for 25 percent global energy requirements (Bayat, 2003)

India produces around 210 million tonnes of food grains and almost 130 million tonnes of fruits and vegetables. Wastage in India, from the farm to fork, is estimated to be very high in all types of food.

Hence value additions to the wastes and by-products are very good option to enhance the contribution of the sector in Indian economy

Agriculture waste based lignocellulose is cheapest and most abundant renewable resource and sustainable solution for raw material source for energy, chemical

Biomass and Its sources

Environmental Relevance

Leaking and improper storage of agricultural waste can also pose a serious threat to the environment In addition, farming activities can give rise to emissions of ammonia and methane which can cause acidification and contribute to greenhouse gases emissions There are a number of potential environmental impacts associated with agricultural waste, if it is not properly managed

Biomass and Its Utilization

Agro waste based biomass resources : Rice husk, Rice straw, wheat straw, Maize Straw, Sugar cane waste, animal waste and many more

Agriculture waste based biomass contain mainly non-edible lignocellulose (cellulose, hemicellulose and lignin biomass) component

Biosynthesis of agriculture based bioproducts such as biofuels and biochemical

Waste based economy will reduce costs through improved production efficiencies

Cleaner agriculture bio products and bioprocesses for the production of material wealth

Biomass to Energy

The biomass can be:

Burned

Transformed into a fuel gas through partial combustion

Into biogas through fermentation

Into bio alcohol through biochemical processes

Into biodiesel

Into a bio-oil or into a syngas from which chemicals and fuels can be synthesized

Bio ethanol production from either sugarcane bagasse or corn stalk

Biomass is the most common form of carbonaceous materials, widely used in the main research and development for energy and valuable chemicals production, involves following activities:

Biomass combustion

Thermal gasification

Pyrolysis

Biotechnology for fermentation processes

Anaerobic digestion of agricultural wastes

Straw utilization

Environmental systems

Biomass to Energy

Biomass Conversion

Biological processes for the conversion of wastes to fuels include ethanol fermentation by yeast or bacteria, and methane production by microbial culture in anaerobic conditions, biocatalytic methods for the conversion of starch, corn co products, beet sugar, or cane sugar bagasse to value-added oligosaccharides and biochemical conversion of lignocelluloses substrates to cellulose, liquid glucose, and value added chemicals

Agriculture Waste Biomass Conversion

Possible routes to obtain chemicals from sugar cane bagasse (Nossin et al., 2002)

Agriculture Waste Biomass Conversion

Process of Biomass Conversion

Current technologies involve following four major routes for nonedible lignocellulose conversion to valuable chemicals (Simonetti and Dumesic, 2008)

Gasification

The gasification process involves:

Requires high temperatures more than 1100 K

Necessary for the endothermic formation of synthesis gas (Lange, 2007) a valuable mixture of CO and H2

Co-feeding an oxidizing agent such as oxygen, air, stream in the gasifier which causes partial combustion of the biomass

Can be used to process all the three component of lignocellulosic biomass

The synthesis gas obtained can be used to produce methanol

Pyrolysis/liquefaction

Pyrolysis and liquefaction involve:

The thermal decomposition of agriculture waste biomass under an inert atmosphere at lower temperatures 573K–973 K

Convert biomass to a dark organic liquid, commonly known as bio-oil

Consists of a complex mixture of more than 300 highly oxygenated compounds, polymeric carbohydrates, lignin fragments and a water content of typically 25 wt%

Bio-oils are good sources of chemicals

High oxygen content of the molecules present in bio-oils confers this liquid with low energy content

Requires further deoxygenation, which typically involves consumption of an external supply of H2

Can be used as a transportation fuels

Hydrolysis

Acid and enzymatic hydrolysis is effective for separating the carbohydrate and lignin fractions of lignocellulosic feeds at lower temperatures

The complex structure of lignocellulose, with its highly crystalline, low–surface area cellulose protected by lignin, confers this material with a high degree of recalcitrance, which makes its depolymerization into the corresponding monomer sugars a difficult task

Effective pretreatment step must be employed to break the lignin protection so that the acids or enzymes can more easily access and hydrolyze the cellulose and hemicellulose fractions of the biomass

The lignin network is modified in aqueous solutions at mild temperatures, which allows the hydrolysis of hemicellulose to occur under the same conditions in the presence of acids

Pretreatment methodologies involving physical, chemical and biological treatments have been developed to depolymerize lignocellulosic materials

Bioconversion

Biological processes for the conversion of agriculture wastes to fuels include ethanol fermentation

By help of Microorganism like yeast or bacteria

Methane production by microbial consortia under anaerobic conditions

Referred to as the enzyme-mediated conversion of organic substrates, such as cellulose, to other more valuable substances, such as protein

Bacterial decomposition of organic waste to produce ethanol, methanol

Technology based classification of biofuels and biochemicals

Biomass based fuels and chemical categorized in three main category (Frost, 2005)

First generation biofuels and bio based chemicalsIntegrated bio refinery technologyCustom designed biofuels

Chemicals Produced from Agro-waste : Few example

Chemicals Agriculture waste resourse

Applications References

Ferulic acid Wheat bran Antioxidant,antimicrobial, anti-inflammatory, antithrombosis,anti-cancer and antibiotic

Sarangi and Sahoo, 2010

Vanillin Wheat straw, Rice straw, Rice bran oil, Sugar beet pulp, Wheat bran

Flavor for food, perfume, drink and pharmaceuticals industries

Herrmann et al., 2000Zheng et al., 2007Apiwatanapiwat and Vaithanomsat, 2009Thibault et al., 1998

Acrylic acid Sugar cane baggase Used in manufacture of various plastic coatings,adhesives elastomers ,floor polishes, and paints

Lunelli et al., 2007

Lignin Rye straw For synthesis of Gallic acid, Protocatechuic acid,p-Hydroxybenzoic acid,p-Hydroxybenzaldehyde, Vanillic acid, Syringic acid, Vanillin, Syringaldehyde p-Coumaric acid, Ferulic acid

Sun and Cheng , 2002

Challanges

conversion of agriculture waste biomass and biomass-derived compounds into fuels and chemicals addresses many of the current issues like sustainability and renewable resources

biological processes for the production of fuels and chemical have been well established, but these processes must still be integrated into a system capable of meeting basic requirements for overall efficiency of converting solar energy into biofuels and biochemicals. So a model system must at least in principle, be capable of easy scale-up and not be limited by either engineering or economic factors

To accelerate the partial replacement of fossil fuels, technologies for the production of valuable chemicals and energy from renewable biomass resources should be economically competitive with petrochemical industry in terms of complexity of processes employed to convert biomass to fuels and chemicals

 

References

Bayat F (2003) Effective factors in agricultural losses, and ways to combat it. Paper presented in the first conference in prevention methods of natural resources, 19-21 Jan. Farhangestan Olom, Tehran. (In Farsi)

Frost J (2005) Redefining chemical manufacture replacing petroluem with plant-derived feedstocks. Industrial Biotechnology 60:23-24

Lange JP (2007) Lignocellulose conversion: an introduction to chemistry, process and economics. Biofuels Bioproducts Biorefining 1:39–48

Nossin, P, Joosten J, Bruggink A (2002), Future feedstocks for commodity advancement: An Overview. Bioresource Technology 16:2354-2366

Simonetti DA, Dumesic JA (2008) Catalytic strategies for changing the energy content and achieving C–C coupling in biomass-derived oxygenated hydrocarbons. ChemSusChem 1:725–733