Waste Tyres Pyrolysis for Obtaining Limonene

Abstract

This review deals with the technologies of limonene production from waste tyre pyrolysis. Thermal decomposition is attractive for tackling the waste tyre disposal problem, as it enables both: energy to be recovered and limonene to be obtained. This material management recycling of tyres is environmentally more beneficial than the burning of all valuable products, including limonene. Given this recoverability of materials from waste tyres, a comprehensive evaluation was carried out to show the main effect of process conditions (heating rate, temperature, pressure, carrier gas flow rate, and type of volatile residence and process times) for different pyrolytic methods and types of apparatus on the yield of limonene. All the results cited are given in the context of the pyrolysis method and the type of reactor, as well as the experimental conditions in order to avoid contradictions between different researchers. It is shown that secondary and side reactions are very sensitive to interaction with the above-mentioned variables. The yields of all pyrolytic products are also given, as background for limonene, the main product reported in this study.

Waste tyre pyrolysis – Impact of the process and its products on the environment

“…Limonene is the compound which is attracting the most attention of potential investors because of its wide use in many applications combined with high proportion of the pyrolysis oil [65].…”

Influence of Specific Power on the Solid and Liquid Products Obtained in the Microwave-Assisted Pyrolysis of End-of-Life Tires

“…As observed in Table 3, the presence of limonene is higher in samples from truck tires, since it has a higher natural rubber content [8,61].…”

“…Another possible mechanism is the one that would take place through the dimerization of the isoprene molecules that are formed in the pyrolytic process at high temperatures through a Diels-Alder reaction [32,53,58,59]. Both mechanisms occur simultaneously during pyrolysis, although the contribution of each of them to the formation of total limonene depends on the reaction conditions and the type of tire used [8,32,60].…”

“…The liquid fraction consists of a mixture of C6-C24 hydrocarbons, where aromatic, aliphatic, and some oxygenated, nitrogenous, and sulfur compounds predominate [6,7]. This fraction could be an important source for obtaining high value-added chemical compounds, such as aromatic hydrocarbons, BTEX (mixture of benzene, toluene, ethylbenzene, and xylene), or limonene [8,9]. In addition, due to its high heating value of 41-44 MJ/kg [10], it could be used as fuel.…”

Lessening coke formation and boosting gasoline yield by incorporating scrap tire pyrolysis oil in the cracking conditions of an FCC unit

“…gasification [11][12][13][14][15] and pyrolysis [7,[16][17][18][19] are emerging. Particularly, the flash pyrolysis of waste tires gives way to three main product fractions, which are highly dependent on the type of tires, the operating conditions, and the reaction technology used [1,[20][21][22]: a gas phase, with a high energy content; a solid product (adulterated carbon black), to be valorized via gasification or applied as adsorbent or catalyst support (after sulfur removal); and, a liquid phase, so-called scrap tire pyrolysis oil (STPO), with promising prospects for fuel blending [6,7,23,24] and for the production of added-value chemicals, such as aromatics BTX (benzene, toluene and xylenes) [25][26][27] and limonene [28], among others. However, the STPO shows several drawbacks for being directly used as automotive fuel, due to its high content in heteroatoms and aromatics.…”