Wood preservation a long-practised method and often used in today's carpentry workshops. Technological developments mean it is also possible to spray preservative over the surface of the timber. Some of the liquid is drawn into the wood as the result of capillary action before the spray runs off or evaporates, but unless puddling occurs penetration is limited and may not be suitable for long-term weathering. By using the spray method, coal-tar creosote, oil-borne solutions and water-borne salts (to some extent) can also be applied. A thorough brush or spray treatment with coal-tar creosote can add 1 to 3 years to the lifespan
Coal liquefaction industrial scales (i.e. thousands of barrels/day) a coal liquefaction plant typically requires multibillion-dollar capital investments. A number of carbonization processes exist. The carbonization conversion typically occurs through pyrolysis or destructive distillation. It produces condensable coal tar, oil and water vapor, non-condensable synthetic gas, and a solid residue - char. One typical example of carbonization is the Karrick process. In this low-temperature carbonization process, coal is heated at to in the absence of air. These temperatures optimize the production of coal tars richer in lighter hydrocarbons than normal coal tar. However, any produced liquids are mostly a by-product and the main