Abstract:

The vapor-liquid equilibrium data of pine resin system with the content of rosin among 0 to 70% as well as the effect of desorption of superior oil of turpentine(95.85% α-pinene) and medium oil of turpentine(36.00%α-pinene) from the distillation of oleoresin were determined by modified Ellis equilibrium cell and gas chromatography at the temperature of 428.15-488.15 K and atmospheric pressure. The results showed that the phase equilibrium temperature increased by the content increasing of rosin in oleoresin, which indicated that the lower concentration of turpentine in oleoresin was, the higher distillation temperature of oleoresin was, that was to say, the turpentine components were difficult to be desorbed from rosin. However, the content of rosin had little influence on vapor-liquid equilibrium data of distillate composition in turpentine. According to the results of vapor-liquid equilibrium properties and the effect of desorption, circulating N₂ or CO₂ distillation method the was designed to modify the process of pine gum distillation. Compared with traditional overheated steam method, the annual consume of standard coal, cooling water and greenhouse gas CO₂ by circulating N₂ or CO₂ method based on 10 000 tons of rosin were decreased by 567.4-694.0 tons, 1.329×10⁵-1.624×10⁵ m³ and 2 080-2 545 tons, respectively. The production processes of separator for oil from water and filter for salts were not required. Water was not contaminated in products of rosin and turpentine. There was no emission of waste gas, waste water with turpentine and waste salts. The loss of turpentine and the emissions of waste salt were decreased by 13.52-29.72 tons and 60 tons annually. The obtained rosin and turpentine products met the national standard requirements.

Key words: pine gum, rosin, turpentine, N₂/CO₂, vapor-liquid equilibrium