vol. 1, 2005

Full text of each article is available in PDF format. CD with full texts could be ordered on our web site.
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 MW.

Environmental impact of biogas from waste dump
Pikoń K.
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.

Recycling of secondary materials from municipal wastes
Alwaeli M.
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 laboratory scale
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 mixture.

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 waste incineration
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
Jaworski T.
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.