Лако-красочные материалы — производство

This method of producing carbon black is a non-continuous or cyclic process, with natural gas as the most commonly used feedstock, although higher-grade hydrocar­bon oils are used. A thermal black plant delivers maximum efficiency when operating in a tandem mode. It consists of two reactors operating alternately in cycles lasting between 5 and 8 min, one of which is heated with a natural gas or oil/air mixture while the other one is fed with pure feedstock, which undergoes thermal decomposition.

One could also include the thermal black method in the group ofthermal-oxidative processes, with the distinction that energy generation and decomposition reaction are not simultaneous. However, the fact that the actual carbon black formation takes place in the absence of oxygen and at decreasing temperatures results in carbon black properties that are markedly different from those achieved with thermal-oxidative processes.

Thermal blacks are formed relatively slowly, resulting in coarse particles in sizes ranging from 300 to 500 nm, referred to as medium thermal. However, formerly, when using natural gas only as feedstock, it was possible to dilute it with inert gases and produce a thermal black consisting of particles in the range of 120 to 200 nm. This was referred to as fine thermal although it has virtually disappeared from the market.

Thermal blacks are used for mechanical rubber goods with high filler contents. Cheaper products (clays, milled coals, and cokes), however, have gained increasing importance as substitutes in recent years. The total production of thermal blacks is, therefore, decreasing.

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