Carbon Black in Dust Collection and Baghouse Systems
Carbon black is nearly pure carbon in colloidal form, generally produced by incomplete combustion of heavy hydrocarbons. Some of the major uses of carbon black are:
- A reinforcing agent in rubber products, where it greatly reduces wear and abrasion. The primary application is in pneumatic rubber tires, where carbon black comprises about a quarter of the total weight. This application accounts for about 90% of the total usage of carbon black.
- A black pigment in paint and ink
- A component of various plastics, protective coatings and resistors
Carbon black is usually specified in terms of particle size. The finer grades are used mostly in pigments, and the smaller particles have the greater tinting strength, making it more valuable. The most commonly used process to make carbon black is known as furnace black. In this process, heavy aromatic oil is atomized and brought into a hot gas stream, where it vaporizes and pyrolyzes to form extremely small particles of elemental carbon. The carbon black thus produced is cooled and conveyed to a dust collector.
Although the initial carbon black particles are microscopic (15-300 nm), the product leaving the furnace has a considerably larger particle size. Within the furnace, the particles coalesce rapidly to form aggregates, which become indivisible. Strong electrical forces bond hundreds of aggregates together to form agglomerates which, once formed, do not break down. The agglomerated product leaving the furnace has a particle size range of 1-100 microns, well within the range which can be collected on fabric filters, pleated filters or cartridges. Carbon black is usually formed into pellets of 100-1000 microns for shipping.