Preface
The world's energy situation, whether in developing or
industrialized countries, is an issue frequently discussed under economic,
technical and political aspects. While it has meanwhile become common knowledge
that today's main resources of energy such as coal, crude oil, natural gas and
even nuclear energy will become scarce within the next generation the renewable
sources such as hydro-, wind- solar- and bioenergy are gaining more and more
importance in terms of research and development as well as implemented systems.
A common feature of renewable energies is that they are mainly available through
a decentralized, sometimes even individual approach. This generates a chance of
having energy at one's own disposal but creates a problem of management and
network when large energy quantities are required.
Some developing countries find themselves under considerable
energy constraints. While the growing demand for household energy decreases the
fuelwood reserves and increases desertification, their foreign exchange earnings
do not allow for sufficient importation of energy. Their potential for other
renewable energies may be large but is not sufficiently exploited for reasons
like lack of capital and expertise. Industrialized countries, though still in a
position to import energy, are feeling the burden of ever-increasing energy cost
while their renewable energy potential is not tapped for, amongst others,
political reasons.
The issue "biogas" tends to initiate adverse reactions, ranging
from blind enthusiasm and belief via critical openmindedness or sympathy to
total rejection. Critical sympathy appears to be a good precondition for coming
to terms with biogas issues and for a successful development of biogas-related
projects.
The biogas technology has been steadily developed within the
last fifty years from small individually designed units to industrial plants
with sophisticated boundary technology. The development, however, has largely
taken place on the side of biogas production and anaerobic waste treatment. The
utilization of the gas has only recently been given more attention as larger and
more sophisticated biogas systems require or depend on a sensible utilization of
the larger gas quantities. Transforming the energy from biogas into the
thermodynamically higher valued mechanical energy marks one of the sensible
options wherever appropriate.
The aim of this publication is to build a bridge between the
elaborate literature and information on the biogas production side and the
existing technical and scientific know-how on the side of internal combustion
engines. An engine fuelled by biogas shall become understandable as a core
module in a system of energy supply, energy transformation and a demand of
energy for a useful purpose. This publication attempts to provide a source of
essential information for decision-making, planning, modification and operation
of biogas engines within this system.
The author hopes to contribute to the better understanding and
the further development of the utilization of biogas for motive power. As this
book is written while a large number of experts are working on and further
developing similar issues in the field as well as in the laboratories, the
author wishes to encourage the readers of this book to come forward with
discussions, criticism and suggestions for further improvement on its contents
and the form of presentation.
I wish to express my sincere gratitude to the GTZ and GATE for
graciously helping to produce this publication. The cooperation with the
corresponding department, especially with Dr. P. Pluschke, Mr. M. Homola and Ms.
H. Mende, was agreeable, stimulating end marked by mutual understanding.
Likewise the author is indebted to suppliers and manufacturers of engines,
biogas ancillaries and modification equipment who provided data and
specifications of their products as well as much useful discussion. Many thanks
go to Ms. K. Pfeiffer who drew most of the figures and diagrams. For the tedious
job of processing a partly difficult to handle manuscript and for useful
assistance in editing Mr. B. v. Mitzlaff deserves the author's special thanks.
Göttingen, September 1986
Klaus v.
Mitzlaff
