Automatyczne sterowanie jakością spalania paliwa stałego w kotłach przemysłowo-grzewczych

The issue of improvement of organic fuel combustion provides for common solving of complex and often contrary problems of increase of its economic use and, at the same time, decrease of emission of harmful components into the atmosphere. One of the most perspective solutions of energy-saving and ecological modernization is optimization of the combustion process according to the criterion of economy and ecological excellence. Technological measures constitute one of the ways of modernisation (figure 1), which, at the same time, makes it possible to solve the ecological and energy-saving constituent of the optimisation process without applying expensive structure changes. Such solutions are, at the same time, oriented on choking of nitrogen oxide and increase of completeness of fuel combustion. The effectiveness of such solutions largely depends upon capacities of basic and auxiliary boiler equipment, burner construction, furnaces, pressure and exhaust fans, control automation degree and quality of technological parameters. One of the most significant issues relating to use of technological solutions is optimisation of parameters affecting the value of generalised energy-saving and ecological criterion. It is possible to achieve maximum optimisation effect only by use of automatic control of controlled factors on the basis of microprocessor automation systems. In practice, the most commonly used systems are systems of "fuel-air" relation, which control air flow in accordance with the concentration value of free oxygen or in proportion to the fuel flow. As shown in their definition, such systems cannot ensure simultaneous solving of fuel saving problems and decrease of emission of harmful fuel components into the atmosphere. Test results as well as experience gained from numerous implementations of the team proved that it is possible to achieve promptness and ecological efficiency in relation to the existing boilers complying with requirements of the EU for gas and liquid fuel combustion. The aim of further research was to disseminate the methods developed in relation to boilers fueled by solid fuel. The subject of the research was a series of WR boilers designed to operate for industrial and heating purposes (Table 1). The boilers are equipped with a traditional layered furnace with a mechanical scaly bed (Figure 2). Following selection and justification of control ideology (Figure 3), the authors developer rules for automatic control of fuel combustion quality. The concept of optimal control makes it possible to realize its algorithm on the basis of simultaneous measurements of oxygen and carbon dioxide in the fumes. The algorithm is a basis of operation of solid fuel combustion automatic control system (Figure 4), which contains a new element, namely zonal control of air flow. The envisaged effect of the system use is 10% of fuel saving per year with accompanying decrease of nitrogen oxides emission into the atmosphere by 20÷60%.