Channel black process

Erom World War I to World War II the channel black process made most of the carbon black used worldwide for mbber and pigment appHcations. The last channel black plant in the United States was closed in 1976. Operations stiU 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 od-fumace process grades that were equal or superior to channel black products particularly for use in synthetic mbber tires. 

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. 

Both processes are still used in industry for the production of carbon black. The channel black process, a process for making impingement blacks, has been used in the United States since the end of the 19th century. This process, which has now been abandoned because of economic and environmental considerations, used natural gas as raw material. A similar process for the production of impingement blacks, the Degussa gas black process, is still used today. 

The furnace black process is currently the most important production process. It accounts for more than 95 % of the total worldwide production. The advantages of the furnace black process are its great flexibility in manufacturing various grades of carbon black and its better economy compared to elder processes. The following comparison makes this apparent for similar grades of carbon black, the production rate of one flame is ca. 0.002 kg/h for channel black, ca. 0.2 kg/h for gas black, and ca. 2000 kg/h for a modern furnace black reactor. However, in spite of the more advantageous furnace black process, the production processes listed in Table 27 (except for the channel black process) are still in use for the production of special carbon blacks which cannot be obtained via the furnace black process. 

In the past decades the rapidly expanding automobile industry required increasing numbers of tires with various characteristics. This led not only to the development of new rubber grades, but also to the development of new carbon blacks required by the increasingly refined application processes and to the development of a new and better manufacturing process, the furnace black process. Unlike the old channel black process, this process allows the production of nearly all types of carbon black required by the rubber industry. It also meets the high economic and ecological requirements of our times. 

The channel black process, used in the United States since the late 19th century, is the oldest process for producing small-particle-size carbon blacks on an industrial scale. Originally, the first reinforcing blacks were also produced by this process. In 1961, the production of channel black was about 120 000 t. The last production plant in the United States was closed in 1976, due to low profitability and environmental difficulties. Natural gas was used as the feedstock. The carbon black yield was only 3-6%. 

In Germany, where natural gas was not available in sufficient amounts, the gas black process was developed in the 1930s. It is similar to the channel black process, but uses coal tar oils instead of natural gas. Yields and production rates are much higher with oil-based feedstock this process is still used to manufacture high-quality pigment blacks with properties comparable to those of channel blacks. The gas black process has been used by Degussa on an industrial scale since 1935. 

The channel black process involves the impingement of natural gas flames on 20- to 25-cm channel irons that are slowly reciprocated over scrapers to remove soot deposits. The type of black produced is controlled by burner-tip design, burner-to-channel distance, and air supply (degree of partial combustion). 

The channel black process is the oldest process for the manufacture of fine particulate carbon black and was operated in the USA from the end of the nineteenth century to 1976. The fine particulate channel black first made possible the production of long-lived car tires with a mileage of several tens of thousands of miles. 

In the channel black process natural gas is burnt in many small glowing flames in contact with water-cooled iron rails, so-called channels . It is no longer operated due to the minimal utilization of raw material (3 to 6%), incomplete carbon black deposition and the resulting environmental problems. 

The gas black process was developed in the 1930 s by Degussa AG as an alternative to the channel black process, because natural gas was not available in sufficient quantities in Germany. 

Advantages compared with the channel black process ... 

An application-oriented classification of pigment blacks distinguishes between High Color (HC), Medium Color (MC), Regular Color (RC) and Low Color (LC) pigment blacks. A third capital letter relates to the manufacturing process furnace black process (F) or gas black process (C, from the historically similar channel black process). 

Several methods can be used for the production of carbon black. The Lampblack Process, the oldest of all, was developed by the Chinese. Initially, vegetable oil was burned in small lamps with tile covers to accumulate the carbon black formed. Later, shallow pans were used in systems with a restricted air supply. Carbon black in this process was recovered from smoke in settling chambers. This method is still used for production of small quantities of carbon black. The Channel Black Process is another method useful in the past and not important for present production. Natural gas is used as a raw material in this process it is burned in close proximity to steel channels on which carbon black is deposited. Carbon black is removed from the channels by scrapers and falls into hoppers beneath the channels. This process was discontinued in the USA in 1976 because of the price of natural gas, smoke pollution, and low yield. It is still being used in Germany, Eastern Europe, and Japan. 

In the channel black process, diffusion flames burning natural-gas impinge on reciprocating metal channels where carbon is deposited. Rotating drums may also be used. The carbon is scraped off, collected, micro-pulverised and then usually pelletised. These blacks have a much higher combined oxygen content than furnace blacks. This process is little nsed now largely dne to unfavourable economics and environmental problems. 

There are several different ways of manufacturing of carbon black. The oldest method is burning vegetable oil in a small lamp, then collecting the carbon black accumulated on the tile cover. This was developed by the ancient Chinese and is called the lampblack process. Subsequently, natural gas was used as a source for what is called the channel black process [26, 53, 54]. This method burns natural gas at about 1,300 C and collects carbon black deposited on steel channels. When exposed to air at high temperature, channel process carbon blacks appear to become porous. 

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