Pyrolysis oil are affected by temperature, reaction time, algae species, algae concentration, reaction atmosphere, and catalysts, in subcritical water reaction conditions. Bio-oil typically requires significant additional treatment to render it suitable as a refinery feedstock to replace crude oil derived from petroleum, coal-oil, or coal-tar. Tar is a black mixture of hydrocarbons and free carbon obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is
East Broad Top Railroad and Coal Company of the oldest railroad roundhouses in the US still in operation, was built in 1882. A coal cleaning plant and a full maintenance shops complex were also built, bridges were upgraded from iron and wood to steel and concrete, wood rolling stock was replaced by steel, and modern high-powered steam locomotives were bought from the Baldwin Locomotive Works of Philadelphia. In the 1950s, coal demand plummeted as homes and industries switched to cheap oil and gas. The last nail in the coffin came when the silica brick plants in Mount Union converted to oil and gas and not enough coal