Oil furnace process

This is a more advanced partial combustion process. The feed is first preheated and then combusted in the reactor with a limited amount of air. The hot gases containing carbon particles from the reactor are quenched with a water spray and then further cooled by heat exchange with the air used for the partial combustion. The type of black produced depends on the feed type and the furnace temperature. The average particle diameter of the blacks from the oil furnace process ranges between 200-500 A, while it ranges between 400-700 A from the gas furnace process. Figure 4-4 shows the oil furnace black process. 

Selected properties of carbon black from an oil furnace process... 

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 acetylene (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 liquid hydrocarbons has found applications 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 oil-furnace process. Since over 95% of the total output of carbon black is produced by the oil-furnace process, this article emphasizes this process. 

The first commercial oil-furnace process was put into operation in 1943 by the Phillips Petroleum Co. in Borger, Texas. The oil-furnace blacks rapidly displaced all other types used for the reinforcement of mbber and today account for practically all carbon black production. In the oil-furnace 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 qualities can be produced. 

The oil furnace process uses aromatic petroleum oils and residues as feedstock and in the oil furnace process (Fig. 1), a highly aromatic feedstock oil (usually a refinery catalytic cracker residue or coal tar-derived material) is converted to the desired grade of carbon black by partial combustion and pyrolysis at 1400 to 1650°C in a refractory (mainly alumina) -lined steel reactor. 

The gas furnace process, is similar to the oil furnace process but, like the thermal black process, uses natural gas as feedstock. 

The oil furnace process is the most common method of production today and is the source of over 95% of the total output of carbon black globally. In this process, a heavy aromatic fraction of petroleum distillate is atomized and sprayed into a furnace preheated to 1200-1900°C. The feedstock vaporizes and decomposes to form carbon black and combustion gases that are immediately cooled with a series of water sprays and heat exchangers to terminate the carbon black reaction and cool the carbon black product stream. The carbon black is separated from the combustion gases in bag filters and is conveyed for further densification either in pelletization processes or in agitator tanks (from which powdered, fluffy black is collected). 

Modern carbon black products are direct descendants of early lampblack , first produced in China over 3500 years ago. These early lampblacks were not very pure and differed greatly in their chemical composition from current carbon blacks. Since the mid-1970s most carbon black has been produced by the oil furnace process, which is most often referred to as furnace black. Table 4.1 contains selected information on carbon black. 

The oil-furnace process was first introduced by Phillips Petroleum at its plant in Borger, Texas, in 1943. This process rapidly replaced all others for the... 

Oil-Furnace Process. The oil-furnace process accoimts for over 95% of all carbon black produced in the world. It was developed in 1943 and rapidly displaced prior gas-based technologies because of its higher sdelds and the broader range of blacks that could be produced. It also provides highly effective capture of particulates and has greatly improved the environment aroimd carbon black plants. As indicated in the mechanism discussion, it is based on the partial combustion of... 

Impingement (Channel, Roller) Black Process. From World War I to World War II the channel black process made most of the carbon black used worldwide for mbber and pigment applications. The last channel black plant in the United States was closed in 1976. Operations still exist and are even being expanded in Europe. The demise of channel black was caused by environmental problems, cost, smoke pollution, and the rapid development of oil-furnace process grades that were equal or superior to channel black products particularly for use in synthetic rubber tires. 

Carbon Fillers. The application of carbon black (qv) in rubber compounds is over a hundred years old. Unlike the well-known crystalline forms of carhon, such as diamond and graphite, carbon black is amorphous and is a manufactured product (79,80). Carbon blacks are prepared by incomplete combustion of hydrocarbons or by thermal cracking. Presently, almost all rubber-reinforcing blacks are manufactured by the oil furnace process. A fuel is burned in an excess of air to produce finely divided carbon. Furnace blacks have low oxygen contents with neutral or alkaline surfaces. In the thermal process, oil or natural gas is cracked in an absence of oxygen to produce unoxidized blacks of small surface areas, or thermal blacks. 

Carbon black can be produced using several methods, including the lampblack, channel black, thermal black, and acetylene processes. However, the vast majority - over 90% - of today s carbon black is manufactured using the oil furnace process, a highly efficient method that permits rigid control of chemical and physical properties. The oil furnace process yields carbon black in fluffy or low-density powder form. Many grades are subsequently converted to pellets (beads) for ease of handling. 

The oil furnace process involves a liquid hydrocarbon, usually a heavy petroleum oil, which is injected, sprayed, and mixed with preheated air and natural gas in a reactor. Part of the hydrocarbon is burned to maintain the reaction temperature ranges of 1,450 to 1,800 °C and the remainder is converted to carbon black. This process has a lower residence time and yields a narrower distribution of carbon black aggregate sizes, higher surface activity, and open aggregates (branched or grapelike (bulky)). 

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