Vacuum treated wood
Introduction
Creosote is a carbonaceous chemical compound derived from the fractionation of various types of pitch[2] and the pyrolysis of materials of plant origin, such as wood or fossil fuels such as coal, preferably at temperatures between 900 and 1200 °C. The mentioned fractionation is carried out between 180 and 400 °C. They are generally used as preservatives or antiseptics.[3].
The IRAM 9512 standard defines it as follows: "Product consisting of a mixture of compounds distilled from coal tar, free of any mixture of petroleum oil or oils not derived from coal tar." It was discovered by Carl Reichenbach in 1833 and patented by John Berthell" in England in 1838.
The composition is very varied depending on the different uses.
The main property is its biocidal qualities against the agents that cause wood deterioration, which is protected by impregnating it with the product through a process that is usually carried out in an autoclave and is called creosoted.
It is also characterized by being a byproduct of the combustion of firewood, which adheres mainly to the interior walls of the barrels (pipes) of stoves and chimneys that use this fuel.
Creosote as a wood preservative
Obtaining creosote
For a brief description of how creosote is produced industrially, we can indicate that coal is a mineral coal from the primary era (Carboniferous). Once extracted, it is introduced into an oven to coke it, obtaining coke on the one hand (which is used in the blast furnaces of steel mills), and vapors on the other that reach a tar condenser. From this condenser, in addition to pitch, gases are obtained, which, when subjected to different industrial processes, give ammonium sulfate, pyridine, etc. as final products. This pitch goes to the distillery "Refinery (distillery)"), and from its fractionation it is obtained: naphthalene oil, anthracene oil, phenolated oil, washing oil and pitch. The mixture of the first four in the proportions required to comply with the IRAM standard forms the product known as creosote.