Biofuels for Africa.

By George Mwaniki

Introduction

• Africa is the second largest continent which accounts for 22% of the earths land mass.

• It is home to ~900million people distributed in 54 independent countries.

• Most Nation in the continent are classified as developing nations.

• Electricity is available to less than 20% of the population in many of this nations.

Introduction ContinuedDespite the economic booms in many parts of the world Africa remains underdeveloped and with minimal economic growth.

Introduction Continued

Gross national income (US$)

Income per capita 2006

Introduction Continuation. • The equator cuts across the continent dividing it almost to equal

halves, thus solar energy is plenty through out the year.

• Access to energy is essential for the reduction poverty and promotion of economic growth.

• By investing in the long term energy solutions, most African nations would benefit significantly in the longer term by avoid the pending economic problems developed countries are currently facing.

• While a great number of projects are currently underway to expand and connect the existing grid networks, too many problems exist to make this a realistic option for the vast majority of people in Africa, especially those who live in rural locations.

• Distributed generation using renewable energy systems is the only practical solution to meet rural energy needs.

Backgroung

• This project is aimed at exploring various options for Biofuels in African, and the discussion is provided in the following web links.

• http://mtech.facebook.com/group.php?gid=7982085278• https://mysite.wsu.edu/personal/gmwaniki/default.asp• https://mysite.wsu.edu/personal/gmwaniki/default.asp• From the discussion, agricultural wastes was chosen to

be the best alternative for biofuel production.

Background.

• The design presented here was proposed by Kelly and her group from Montana tech.

• This presentation will be as follows– A summarize the data and the technical

aspect of the project.– challenges of its implementation. – Community acceptance of the technology.– Cost analysis.

The proposed Project

• The aim of the project was to develop an alternative fuels to supplement or replace the current fuel supply.

• The supplement fuel was to be:– Clean– Sustainable– Cost effective– Culturally acceptable to the communities

• The proposed design involves the conversion of agricultural waste into biogas, through gasification and later direct combustion.

Proposed project

• The following aspects were considered in the Design of the best technology.– Existing technologies and their pros and cons– Waste products for system to be employed– Environmental impacts of the alternative– Applicability to rural Africa– Ease of use– Reliability– Operation and maintenance costs

Current conversion technologies of biomass is best illustrated by the following figure (adapted from UNIDO)

Existing technologies

• Most of the existing technologies are discussed in the links.

• Most of the existing technologies are not applicable in rural Africa, mainly due to their cost and expertise requirement in implementing, running them and also maintenance.

• A high breed of gasification and direct combustion was picked due to its cost effectiveness, easy to maintain and run.

• It is also more acceptible in rural Africa as it encompuses some of the techniques already in use there, and also due to its small size.

Alternative technologies looked at

• Alcohol fermentation :– Requires heavy capital investment.

• Liquefaction:- The technology is complicated and requires trained persons.

• Anaerobic digestion:- Technology is complicated and so many variables that can go wrong.

• Direct combustion:- Easy and currently in use.

• Gasification:- Can be complicated but its possible to have a simple design.

Selected Technology

Agricultural waste

Gas CO2, CH4, H2, CO and others

Gasifying chamber, heated by charcoal

Charcoal by product

Gas to the house for energy

Produced gas properties

• A comparison of amount of gas produced, with increase in biomass. Is presented in the graph below.

• Gas production increases with increase in mass of the biomass

Gas Produced vs. Biomass Sample Size

y = 0.502xR2 = 0.8972

0

5

10

15

20

0 5 10 15 20 25 30 35 40

Biomass Sample Size (g)

Gas

Pro

duce

d (g

)

(Adapted from Biomass energy)

Quality of gas produced

LHV- low heating value

HHV- Higher heating value

(Adapted from Biomass energy)

Quality of gas produced in %

Gas Components at 550 Degrees CelsiusMole %

14%

19%

28%

32%

3%2%

1% 1%

Oxygen

Propane

Ethane

Nitrogen

Carbon Monoxide

Methane

Hydrogen

Carbon Dioxide

•At a temperature of 550oC the system is expected to be at maximum efficiency. (Adapted from Biomass energy)

Design advantage

• Uses readily available renewable resource ( agricultural waste)

• Minimal waste and waste ashes can be used as manure in the farms.

• Low energy and work input• By product (Charcoal) recycled and used

in the system.• Produces clean energy.• Less smoke encountered in the house

holds.

Design Disadvantages

• Produces carbon dioxide a green house gas, (but net production=0).

• The agricultural waste input has to be dry.• System requires cleaning often due to its

small size.• Due to it high operating temperature there

is some injury risks.• If not well insulated, heat loss will lead to

high inefficiencies.

conclusion

• The final proposal is

•Innovative•Cost effective•Easy and reliable•Little waste•Appropriate for a rural setting.