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All articles have been reviewed by the members of Scientific Board.
Economic aspects of wood combustion in
stoker fired boiler
Poskrobko S., Łach J.
Necessity of protection of natural environment resulted in
enlargement of utilization of local resources of renewable fuels. In
last years, many investments were located in our country in
construction of many boiler rooms assigned for satisfying local thermal
energy needs. Often yet it turns out, that developed quantity of
thermal energy does not agree, particularly in peak periods, with
forecast demand determined on stage of brief fore design, what it is
reason of lack of social acceptance of realized investments. Such state
of affairs can be caused e.g. by incorrect balance of heat demand or
bad technical conditions of heat distribution system from source to
recipients, but usually by lack of detailed analysis of possibility of
work of installed boilers in definite conditions of heat demand.
Independently of ecological aspect, one should to lay emphasis in
frames of conception on assurance of economically justifiable covering
of heat demand, i.e. on detailed and reliable analysis of efficiency of
work of fuel delivery system in heat-generating plant as well as
production and heat transmission. This way it is possible to avoid
undesirable and often dangerous mistakes in service conditions. In the
paper, fundamental questions connected with production of thermal
energy from wood waste have been taken into account. Theirs effective
solution makes possible planning of fuel policy and energy management.
In particular, dependence of boiler balance quantities on such basic
parameters, as: fuel (i.e. wood waste) humidity, excess air coefficient
as well as temperature of air leading to combustion chamber, has been
demonstrated. Analysis of efficiency of burning process was based on
example of water heater with step grate with heating power about 5,815
Environmental impact of biogas from
In the article environmental impact of gas emission from waste dump
which is not equipped with biogas acquisition system and waste dump
where biogas is being used for energetic purposes has been shown. On
the basis of composition and quantity of biogas comparison of two
scenarios – with and without biogas utilization – has been made. The
comparison was made taking as an example real waste dump in Gliwice.
of secondary materials from municipal wastes
An article gives an description of recycling of potential
secondary materials which could be found in municipal wastes. It could
be a crucial element of complex waste management system. Differences
between wastes and primary raw materials properties are not
substantial. Many times these changes overcome only obverse manufactory
form. The reason is that primary raw materials often have not undergo
fundamentally changes during production process. (Scarp metal stay
metal and rubbish stay paper). In this paper the methods and
realizability recycling of municipal wastes (paper, metal, glass,
plastic) were discussed.
Co-combustion of coal with sludge in
Nadziakiewicz J., Czekalski R.
The paper presents results of research of co-combustion process of coal
with sludge carried out in laboratory installation. Six mixtures were
investigated containing 5 up to 30% of sludge (containing 40% of
moisture) as well as clean coal. The research was conceived to
investigate the influence of sludge in fuel mixture on emission of
gaseous substances in exhaust gas, like CO, NOx and SO2. The results
show that influence on the emission of mentioned substances has,
besides changes in composition, also moisture content of the fuel
Optimal number of air supply sections
for the grate fired combustion chambers
Kozioł M., Nadziakiewicz J.
The influence of the number of air supply sections under the
grate on the total air amount for the combustion process along
the traveling grate was analyzed. Six versions of the air supply curves
along the grate was taken into considerations. The shapes of
curves were chosen depending on the type of coal (4 types) and
waste (2 types) supplied as fuel.
Thermal characteristic of a rig for
Wacławiak K., Formanek B.
One pros for the use of pyrolysing chambers is it converts complex
waste into combustible volatile matter and char. The combustion process
is more controllable for such fuel. A shaft type of the pyrolysing
chamber is typical for some waste. It was built a laboratory rig in
order to test the pyrolysing chamber. The tests were carried out
burning plastic waste PE and PP. The plastic waste was received from a
recycling company, and had been processed a few times. The
maximum grain size was about 20 mm, mostly irregular in shape.
The pyrolysis develops very fast and results in the large amount of
combustion gas but combustion produces soot. It can lead to
difficulties in proper air feeding and operation control. The high
heating value results in high temperature and put the used refractory
and the auxiliaries in jeopardy.
Identification of combustion zones in
waste layer on the grid
The incineration process of waste looks simple at a first glance, but
its nature is really complicated, and its organisation undergoes
constant improvements to meet the ecological, energetistic and
economical requirements. Incineration process for the waste material
can be divided into several phases: warming up and drying,
devolatilisation, gasification and combustion. The better understanding
of the combustion process leads to the improvements of the process by
applying new technology as forward movement and reciprocating movement
mechanical grates, flue gas recirculation and other.
The paper presents the analysis of physical and chemical parameters of
the solid waste on the mechanical grate of the installation for its
thermal utilisation. The analysis is based on the data obtained from
the experiments made in the electrical heated chamber similar to the
real combustion chamber. The analysed parameters are: time an
temperature of the combustion process, intensity of combustion process,
combustion air rate, geometry of the combustion chamber and others.
Following parameters of the waste layer were analysed as functions of
time of the process:
· porosity of the layer,
· bulk density of the layer,
· apparent density of the layer,
· height of the layer,
· concentration of the elementary C in the layer.
The experiments were carried out for several temperatures between 600
and 900 deg.C.