Lignocellulose biomass

Many different feedstocks are employed natural gas (methane, ethane, propane etc., petroleum cuts (Liquefied Petroleum Gas LPG, naphtha, fuel oil, vacuum residues, asphalts etc.), coal, biomass (lignocellulose wastes, wood etc.). 

Another potential feedstock for ethanol production is the lignocellulosic biomass . Lignocellulosic biomass is the most plentiful of all naturally occurring organic compounds. It includes such materials as wood, herbaceous crops, agricultural and forestry residues, waste paper and paper products, pulp and paper mill waste, and municipal sohd waste. Unlike starchy materials, lignocellulosic biomass is structurally complex. The conversion of this material into ethanol has been the subject of intense study over the last 20 years. 

In the production of antibiotics, sufficient growth of fungi in submerged cultures has created potential sources of biomass as SCP and as flavour additives to replace mushrooms the biomass contains 50-65% protein.1,5 Production of mushroom from lignocellulosic waste seems to be a suitable and economical process since the raw material is inexpensive and available in most countries. 

Second-generation biofuel technologies make use of a much wider range of biomass feedstock (e.g., forest residues, biomass waste, wood, woodchips, grasses and short rotation crops, etc.) for the production of ethanol biofuels based on the fermentation of lignocellulosic material, while other routes include thermo-chemical processes such as biomass gasification followed by a transformation from gas to liquid (e.g., synthesis) to obtain synthetic fuels similar to diesel. The conversion processes for these routes have been available for decades, but none of them have yet reached a high scale commercial level. 

Of course, the lignocellulose also contains various minor components such as proteins, terpenic oils, fatty acids/esters and inorganic materials (e.g., mainly based on N, P and K). These components will not be considered here owing to lack of space but should not be forgotten as they interfere with many processes. For sustainable biomass production the inorganic materials need to be recycled from the process to the field. 

Various chemistries and processes can be applied to convert lignocellulosic materials into valuable fuels and chemicals [3, 19]. For instance, thermal reactions are exploited in the pyrolysis of biomass to charcoal, oil and/or gases and its gasifica-... 

The char produced by pyrolysis is typically light and porous. Removal of most of the oxygen present in the biomass significantly increases its heating value, e.g., from 17 GJ t 1 for the lignocellulose to some 30 GJ t 1. This makes the char a valuable fuel for industrial and consumer applications. 

Figure 2.13 did not include all the biomass conversion processes discussed above. It only considered those that produce transportation fuels. The processes that convert bio-feedstock into biocrude or electricity could not be included because their products have a different value than the transportation fuels. Such a comparison can be attempted by displaying the total manufacturing cost of biobased products in a graph that shows typical relationships between the price of crude and that its derivatives, i.e., of fuel oil, transportation fuel and electricity. This has been done in Fig. 2.14 for the lignocellulose conversion processes. 

Lignocellulose biomass is a mixture of phenolic lignin and carbohydrates -cellulose and hemi-cellulose. It grows abundantly on earth and is largely available as agricultural and forestry residues. Lignocellulose can be converted via four major routes pyrolysis, gasification, hydrolysis and fermentation. 

Biomass conversion processes are still expensive today, being competitive at crude oil prices between 50 and 100 bbl-1. Lignocellulose might be a fairly cheap feedstock, cheaper than crude oil. However, its conversion requires large... 

This chapter surveys different process options to convert terpenes, plant oils, carbohydrates and lignocellulosic materials into valuable chemicals and polymers. Three different strategies of conversion processes integrated in a biorefinery scheme are proposed from biomass to bioproducts via degraded molecules , from platform molecules to bioproducts , and from biomass to bioproducts via new synthesis routes . Selected examples representative of the three options are given. Attention is focused on conversions based on one-pot reactions involving one or several catalytic steps that could be used to replace conventional synthetic routes developed for hydrocarbons. 

The present chapter discusses aspects, known by the authors, of (a) biomass as feedstock, (b) the concept of bio-refinery, (c) thermochemical routes from lignocellulosic biomass to fuels, and (d) the contribution of catalytic technology. The main focus will be on the catalytic conversion of fast pyrolysis oil into fuels with regard to problems encountered currently and the challenges for future research and development. 

Along with carbon, hydrogen and oxygen, lignocellulosic biomass also contains hetero elements such as alkali and other metals. The amounts of these ashes vary over a broad range, from 30-50 wt.% in chicken litter to 1-3 wt.% in wood. Moisture is always present in lignocellulosic biomass and can be up to 80 wt.% in some cases. Detailed information on the composition of biomasses can be found in data bases, e.g., Phyllis [21] from the Dutch Energy Research Foundation (ECN). Table 6.2 lists the compositions of some typical biomasses. 

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