Carbon black thermal process

The four basic carbon black manufacturing processes are either of the partial combustion type (the channel, oil furnace, or gas furnace process) or of the cracking type (the thermal process). 

Carbon black manufacturing process for thermal black. 

Two processes, partial oxidation and thermal decomposition, are used for the production of carbon blacks. The partial oxidation process can be represented by the foUowiag reaction ... 

The production process or the feedstock is sometimes reflected ia the name of the product such as lamp black, acetylene black, bone black, furnace black, or thermal black. The reason for the variety of processes used to produce carbon blacks is that there exists a unique link between the manufactuting process and the performance features of carbon black. 

In the depolymeri2ed scrap mbber (DSR) experimental process, ground scrap mbber tines produce a carbon black dispersion in ok (35). Initially, aromatic oks are blended with the tine cmmb, and the mixture is heated at 250—275°C in an autoclave for 12—24 h. The ok acts as a heat-transfer medium and swelling agent, and the heat and ok cause the mbber to depolymeri2e. As more DSR is produced and mbber is added, less aromatic ok is needed, and eventually virtually 100% of the ok is replaced by DSR. The DSR reduces thermal oxidation of polymers and increases the tack of uncured mbber (36,37). Depolymeri2ed scrap mbber has a heat value of 40 MJ/kg (17,200 Btu/lb) and is blended with No. 2 fuel ok as fuel extender (38). 

Carbon Black. This is the principal reinforcing filler used in mbber. Carbon black is made by three processes the furnace process, the thermal process, and the channel process. Over 97% of black is made by the furnace process (see Carbon, carbon black). 

A number of processes have been used to produce carbon black including the oil-furnace, impingement (channel), lampblack, and the thermal decomposition of natural gas and acetjiene (3). These processes produce different grades of carbon and are referred to by the process by which they are made, eg, oil-furnace black, lampblack, thermal black, acetylene black, and channel-type impingement black. A small amount of by-product carbon from the manufacture of synthesis gas from Hquid hydrocarbons has found appHcations in electrically conductive compositions. The different grades from the various processes have certain unique characteristics, but it is now possible to produce reasonable approximations of most of these grades by the od-fumace process. Since over 95% of the total output of carbon black is produced by the od-fumace process, this article emphasizes this process. 

The first commercial oil-fumace process was put into operation in 1943 by the Phillips Petroleum Co. in Borger, Texas. The oil-fumace blacks rapidly displaced all other types used for the reinforcement of mbber and today account for practically all carbon black production. In the oil-fumace process heavy aromatic residual oils are atomized into a primary combustion flame where the excess oxygen in the primary zone bums a portion of the residual oil to maintain flame temperatures, and the remaining oil is thermally decomposed into carbon and hydrogen. Yields in this process are in the range of 35 to 50% based on the total carbon input. A broad range of product quaHties can be produced. 

Table 11 Hsts the types and appHcations of special pigment-grade carbon blacks. Included in this Hst are thermal black and lampblack. Over 40 special black grades have been developed based on the furnace process having a broad range of surface areas, from 20 m /g to over 1500 m /g. The lower surface area products are used in printing inks and tinting. The high area, more expensive products find use in high color enamels and lacquers.

Pyrolysis of scrap tires was studied by several mbber, oil, and carbon black industries [14]. Pyrolysis, also known as thermal cracking is a process in which polymer molecules are heated in partial or total absence of air, until they fragment into several smaller, dissimilar, random-sized molecules of alcohols, hydrocarbons, and others. The pyrolysis temperature used is in the range of 500°C-700°C. Moreover, maintenance of partial vacuum during pyrolysis in reactors lowered the economy of the process. Several patents were issued for the pyrolysis of worn out tires to yield cmde oil, monomers, and carbon black in economic ways [15-18]. The major drawback of chemical recycling is that the value of the output is normally low and the mixed oils, gases, and carbon black obtained by pyrolysis cannot compete with similar products from natural oil. Pyrolyzing plant produces toxic wastewater as a by-product of the operation [19]. 

It could be concluded that thermal plasma process for methane decomposition is very effective for the production of high purity of the hydrogen as well as synthesis of the carbon black. 

Carbon blacks are manufactured from hydrocarbon feedstocks by partial combustion or thermal decomposition in the gas phase at high temperatures. World production is today dominated by a continuous furnace black process, which involves the treatment of viscous residual oil hydrocarbons that contain a high proportion of aromatics with a restricted amount of air at temperatures of 1400-1600 °C. 

Carbon black produced by the thermal decomposition of natural gas or atomised oil in a pre-heated refractory furnace where the fuel is cracked into carbon and hydrogen. The process is cyclic, two furnaces being used as one production unit, one furnace being heated up as the other is producing. 

Acetylene Black A process for making carbon black from acetylene by thermal decomposition at 800 to 1,000°C in refractory-lined, water-cooled retorts. 

Channel Black Also called Gas Black. One of the processes used to make carbon black the others are the Acetylene Black, Fumace Black, Thermal Black, and Thermatomic processes. In the Channel Black process, natural gas was incompletely burnt in small flames, which impinged on cooled channel irons that were continuously moved and scraped. Invented by L. J. McNutt in 1892 and commercialized that year in Gallagher, PA. The last United States plant was closed in 1976. 

Furnace Black One of the three principal processes used for making carbon black the others being the Thermal Black and the Channel Black processes. In the Furnace Black process, aromatic fuel oils and residues are injected into a high velocity stream of combustion gases from the complete burning of an auxiliary fuel with an excess of air. Some of the feedstock is burned, but most of it is cracked to yield carbon black and hydrogen. The products are quenched with water. 

Lampblack The original process for making carbon black by the incomplete combustion of oils. Superseded by the Acetylene Black, Channel Black, Fumace Black, and Thermal processes. 

Thermal Black One of the processes used to make carbon black. The feedstock is usually natural gas. The gas is pyrolyzed in one of a pair of refractory reactors which has been preheated by burning part of the feed and hydrogen from the process. When the temperature has fallen, the functions of the reactors are interchanged. 

Coke a gray to black solid carbonaceous material produced from petroleum during thermal processing characterized by having a high carbon content (95%+ by weight), a honeycomb appearance, and is insoluble in organic solvents. 

Both types of surface oxides are found on technical products. Rubber grade carbon blacks are produced in different processes. Channel blacks are made by cooling a flame on iron plates, the so-called channels. The resulting carbon blacks are acidic in character because an excess of air is present (25). In the production of furnace blacks, the fuel, mostly oil or natural gas, is burned with a limited supply of air. Thermal blacks are obtained by thermal cracking of the gas, which sometimes is diluted with hydrogen. In consequence, both types show weakly basic reaction in aqueous suspension. 

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