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Possibilities and limitations of usage of classic coking process as a method of industrial waste utilisation
Języki publikacji
Abstrakty
W chwili obecnej działa w Polsce 12 koksowni, trzy z nich to samodzielne zakłady, a jeden jest kombinatem, natomiast trzy koksownie są przyhutnicze. W ciągu ostatnich 10 lat ilość produkowanego koksu wyraźnie maleje. Przewiduje się, że w roku 1999 produkcja koksu osiągnie wartość około 9 mln Mg i w ciągu najbliższych lat ustabilizuje się na tym poziomie [1, 2]. Aby wyprodukować tę ilość koksu koksownie muszą poddać procesowi koksowania prawie 12 mln Mg węgla. Wykorzystanie tego procesu do utylizacji odpadów przemysłowych poprzez wprowadzenie ich w formie mikrododatków (do 1% wagowego) do koksowanych mieszanek węglowych pozwoliłoby - teoretycznie - na eliminację do 120 tys. Mg odpadów rocznie. Te rozważania ilościowe, jak również znajomość parametrów procesu koksowania (temperatura ścian komory >1200°C, redukujące środowisko, duża liczba wydzielających się reaktywnych związków [3, 4]) oraz możliwość doboru odpowiedniego składu mieszanki węglowej skłaniają do poważnego zastanowienia się.
The paper presents the results of the industrial wastes utilisation during the coking process tests in the laboratory conditions as well as using coking chamber. The paper also presents how wastes added to the coking mixture influence changes of chlorine and sulphur compounds emission from the coking chamber. Also the influence of wastes added to the coal input on the utilitarian parameters of obtained coke is discussed from the point of view of their further usage. The pros and cons of selected wastes utilisation in the Polish coking industry is discussed. To produce 9 millions of Mg of coke, coking plants have to process almost 12 millions of Mg of coal. This process may be used for industrial wastes utilisation by adding them as a micro additives (up to 1% of weight) to coking coal mixtures. This, theoretically, allows to eliminate up to 120 000 Mg of wastes per year. This quantity considerations as well as parameters of coking processes (temperature of chamber walls >1200°C, reductional environment, big amount of emitted reactive compounds) and possibility of proper coal mixture selection induce to use this process as an alternative way of elimination of industrial wastes. Industrial wastes added to the coal mixture as micro-additives (up to 1% of weight) or additives (over 1% of weight) may change chlorine and sulphur emission during coking process in significant way. Those changes may be different as for reduction grade of these elements emission in this process. Wastes containing ammonium ions may increase emission of chlorine and sulphur, mediating in processes connected with chlorine emission, which is consistent with predicted mechanism of this phenomenon. It is possible to utilise wastes containing chlorine as micro-additives or additives to coked coal mixture under one condition: along with wastes substances/wastes decreasing emission of this element in the coking process must be added (associated additives). Such action may also change sulphur emission in this process. Among tested micro-additives/additives the most effective in decreasing chlorine emission during coking process were compounds/wastes containing calcium. However tested substances, containing nitrogen or magnesium, caused increase of chlorine emission and that is why they should not be added to the coal mixture alone. During burning cokes containing increased load of chlorine it may be re-emitted in the degree which depends mainly on burning process conditions, but not on the kind of added additive. Taking into consideration qualitative parameters of obtained cokes in this method, it may be used mainly in coke plants, which produce industrial and fuel coke. Coking plants, which produce blast-furnace coke, may add (under control) Ca(OH)2 or wastes containing this component to the coked mixture. Chlorine compounds inserted along with blast-furnace components inserted to the blast-furnace, get out from reactional space along with blast-furnace gas and accumulate in the wastes (wastewater's and dust from dust collectors) arising in devices, which clean blast-furnace gases. Chlorine may contribute to alkalines removal from the blast-furnace space. Conducted research point to necessity of keeping big caution when using coking process as a universal method of utilisation of any kind of wastes, although very often it is justified technologically. Before using coking process for industrial waste utilisation in a full scale, laboratory research should be conducted.
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Czasopismo
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Tom
Strony
27--56
Opis fizyczny
Bibliogr. 48 poz.
Twórcy
Bibliografia
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BPW7-0006-0046
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