Characterization of high acid value waste cottonseed oil by temperature programmed pyrolysis in a batch reactor

Temperature programmed pyrolysis of high acid value waste cottonseed oil (WCO) was carried out in a batch type reactor. A thermogravimetric analysis (TGA) method, which did not require a carrier gas, was used to study the properties of oil products. Weight loss data were obtained at heating rates (from 5 to 15 degrees C min(-1)) and used to estimate the pyrolysis activation energy. A systematic study of the molecular weight distribution was made for the pyrolysis of WCO and virgin cottonseed oil at different heating rates. The yields of the products including: gases, liquids (collected pyrolytic oil), and solids (residual char) were quantified in this work. The production of pyrolysis gas was estimated during heating. The weight loss results indicated that the optimum pyrolysis rate occurred between 400 and 450 degrees C at a heating rate of 10 degrees C min(-1) from room temperature to 600 degrees C. Our work indicated that high acid value WCO yields comparatively greater volumes of gases and masses of residual products when compared to virgin cottonseed oil. After the temperature programmed pyrolysis of WCO (acid value 8.66 mg KOH g(-1)), at a heating rate of 10 degrees C min-1, the average boiling point of the pyrolytic oil was similar to 349 degrees C, which is significantly lower than that of the unprocessed WCO (456 degrees C). The pyrolytic oil produced in this process after esterification with methanol, was found to comply with biofuel specification requirements. (C) 2016 Elsevier B.V. All rights reserved.