Carbon black furnace 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). 

The time scale of carbon black formation varies substantially across the range of particle sizes found in commercial furnace blacks. For blacks with surface areas around 120 m /g, the carbon black formation process from oil atomization to quench takes less than 10 ms. For blacks with surface areas aroimd 30 m /g, formation times are a few tenths of seconds. 

Furnace carbon black is one of the most important compounding ingredients used in the rubber industry. It is certainly the most important rubber filler because it imparts such a profound improvement on cured rubber properties such as ultimate tensile strength, hardness, wear resistance, and tear resistance. Carbon black even improves the extrusion process by making the extruded rubber product smoother in appearance. By using carbon black with process oil, the rubber compound s pound-volume costs can be significantly reduced. In fact, if a rubber compound is black in color, chances are that it contains 26 to 32% carbon black. The level of carbon black... 

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)). 

Carbon black manufacturing process for furnace black. 

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. 

Kutrieb Corporation (Chetek, Wisconsin) operates a pyrolator process for converting tires into oil, pyrolytic filler, gas, and steel. Nu-Tech (Bensenvike, Illinois) employs the Pyro-Matic resource recovery system for tire pyrolysis, which consists of a shredding operation, storage hopper, char-coUection chambers, furnace box with a 61-cm reactor chamber, material-feed conveyor, control-feed inlet, and oil collection system. It is rated to produce 272.5 L oil and 363 kg carbon black from 907 kg of shredded tires. TecSon Corporation (Janesville, Wisconsin) has a Pyro-Mass recovery system that pyroly2es chopped tire particles into char, oil, and gas. The system can process up to 1000 kg/h and produce 1.25 MW/h (16). 

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). 

The furnace process involves injecting low end fraction of cmde oil, eg. Bunker Euel C, into a heated chamber. The temperature, shape of the injectors of the oil, rate of injection, and other factors are controlled to produce black fillers of different particle si2e and stmcture. The particle si2e and stmcture control the reinforcing character of the carbon black. There are 30 common grades of carbon black used in the mbber industry. There are numerous specialty grades produced, and several hundred are used in plastic, conductive appHcations, and other uses. 

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. 

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.

S 111 fi 1 r-reco ve ry p lants Carbon-black plants (furnace process) Primary lead smelters Fuel-conversion plants Sintering plants Secondary metal-production plants Chemical-process plants ... 

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. 

Figure 4-4. Carbon black (oil black) by furnace process of Ashland Chemical...

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

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. 

A mixture of gaseous hydrocarbons, principally methane, which issues from the earth in certain areas, particularly near petroleum wells. Natural gas was the main source of carbon black until some 50 years ago when it was found more economic to use the gas for heating and produce carbon black from petroleum residues by the more efficient furnace process. 

The fighter gases produced in the distillation of petroleum or the residual gas in the manufacture of carbon black by the furnace process. 

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. 

Ayers An early process for making carbon black from oil. The air for combustion is injected tangentially into the furnace, producing swirl, and the atomized oil is injected into this. Invented by J. W. Ayers and developed by Phillips Petroleum Company. 

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. 

In the second stage, the black ash process, the sodium sulfate was reduced to sodium sulfide and then converted to sodium carbonate by calcining with limestone and coal in a rotating kiln known as a black ash furnace or revolver ... 

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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