JESUS CHRIST IS IMMINENTLY PICKING HIS BRIDE!!!!!: THE LORD BLESS EACH AND EVERY ONE OF YOU DURING THIS COMMEMORATIVE AND REFLECTIVE MOMENT:

God bless everyone welcome all to kisumu crossing over year assemblies leading by mighty prophet dr Edward owuor

Biomass Feedstocks

303

to a central power station and thus overcome the problems of seasonal feedstock supply

and storage.

Upgrading of Bio-Oil Fuel Characteristics

Bio-oil as produced from a fast pyrolysis process has certain disadvantages for use as a

fuel, particularly for diesel applications. The water content must be controlled, preferably

between

ª

15% and 25%. The water is not just a diluent—it acts as a cosolvent and gives a

homogeneous liquid product of relatively low viscosity. If the water content is too low, the

viscosity will be very high, and too high a water content may cause phase separation and

reduce the calorific value of the bio-oil. Also, the bio-oil is corrosive because of the low

pH and is unstable in storage or at higher temperatures. The addition of 5%–10% ethanol

has been found both to aid in control of the viscosity and to give greater stability over time.

Another solution to improve the fuel qualities of the bio-oil is to alter it chemically by

derivatization or by hydrogenation, to reduce the considerable reactivity of the carbonyl

and phenolic components. Both approaches have been demonstrated to be technically

achievable by several researchers, and to yield satisfactory liquids [12–14]. However,

adequate supplies of the upgraded fuels have not yet been prepared to allow commercial

scale testing or to allow full evaluation of the process economics, although such programs

are underway (1997).

Bio-Oils as Chemical Feedstocks

As already pointed out, it is possible to obtain widely different bio-oil compositions

by pretreating the biomass feedstock in various ways before pyrolysis. In addition to

these processes, sand or other solid heat carriers used in a fast pyrolysis unit can be

replaced by a solid catalyst, or by a reactive atmosphere, or both. This technology is

particularly easy to apply in a fluidized-bed process. The catalyst can then be selected

for low-temperature gasification to make synthesis gas [15–17]; if a hydrogen atmosphere

is used with nickel catalyst, a high carbon conversion to methane can be accomplished

[18], or if hydrotreating catalysts are used in a hydrogen atmosphere, good yields of light

hydrocarbons can result [10]. All the above processes take place at atmospheric pressure

and at temperatures from 400 to 700

±

C. Other controlled hydrogenations and oxidations

of the bio-oil are also possible to yield a variety of potentially valuable organic chemicals.

One of the important preliminary steps for many routes to recovering chemicals from

bio-oil is a simple water separation that will precipitate highly phenolic material and

extract water-soluble low molecular weight organics such as hydroxyacetaldehyde. A

typical phase diagram for such an extraction is shown in Fig. 3.39 for a poplar wood

bio-oil. Clearly any water content over 50% in this case will result in phase separation.

The two phases can then be processed separately for chemical recovery.

An attempt is made to summarize many of the potential routes for production of

chemicals from bio-oils in Fig. 3.40. At the present time, the commercial production of

anhydrosugars has been undertaken, particularly levoglucosan by Resource Transforms

International Ltd. (Canada) and of phenolics from the lignin fraction by the National

Renewable Energy Laboratory (USA). However, it is clear from Fig. 3.40 that there

are many potential applications for bio-oil as a chemical feedstock that await only the

development of economically attractive recovery processes.

my the lord bless you,before i proceed i want to tell that messiah is coming back to take holy church ,what does i mean holy church,from the bible holy church was described as:

1. set apart church from word holy in Hebrew:means set path
2. sanctify
3. consecrated