English abstract
The limited resource availability and environmental issues caused by fossil fuels, tends to increase the emphasis on biofuels production, as potentially significant source for transportation and energy production in current era. Production of biofuels from plant based oil have good prospect as potential alternative to fossil based fuels. The concept of utilizing waste Date pits for biofuels production is promising due to its abundant availability in Oman.
Waste Date pits are subjected to oil extraction and the process has been optimized. The optimization studies revealed that maximum oil extracted was 16.5 wt% under these operating conditions; process temperature was 70 °C, time was 7 hrs while the solvent to pits ratio was 4:1. The characterization of oil revealed its feasibility to be used for biofuels production. Two routes were adopted to produce biofuel from Date pits oil; in the first route biodiesel was produced through transesterification and in the second, high value green diesel and jet fuel fractions were obtained through hydrodeoxygenation HDO. For biodiesel production, a bimetallic catalyst, which owned balanced active sites and suitable physiochemical properties for producing biodiesel, is synthesized. The biodiesel production process is optimized by using response surface methodology R$M. The optimized yield of biodiesel was 96.4 % under the following operating conditions; temperature 90 °C, time 4 hrs, catalysts loading 3 wt.% and methanol to oil ratio 15. The quality of produced biodiesel is determined by characterizing the biodiesel by standard methods defined by ASTM and EN. The fuel properties of produced biodiesel satisfied the limits defined by ASTM and EN standards, which assured its potential usage as fuel.
In the second route, Date pits oil was subjected to HDO in the presence of green catalyst. The catalyst was synthesized from waste Date pits powder post oil extraction and it was modified by impregnating it with transition metals (platinum Pt and palladium Pd). The synthesized catalysts were highly efficient and observed that the degree of deoxygenation (DOD) of product oil was 97.5 % and 89.4 % for the Pd/C and Pt/C catalysts respectively. Meanwhile, the product distribution revealed that the maximum fraction of hydrocarbons formed lies within the range of green diesel and part of it in jet fuel.
The waste and by-product such as Date pits powder post oil extraction as a waste and glycerol obtained as byproduct from biodiesel were valorized. The waste Date pits powder, is subjected to the synthesis of sulphonated carbon catalyst. The synthesized catalyst is highly efficient and used for alkylation of phenol and observed to be highly efficient (phenol conversion 79.27 wt.%) to give highly valuable products such as 4TBP+2,4TBP which have wide industrial applications. Moreover, glycerol is converted to solketal, which can be used as fuel additive. So, all these results revealed that waste Date pits are of high potential to be used for various applications.
The novelty of the presented work can be summarized as follow:
The process of oil extraction from waste Date pits has been optimized for the first time along with complete oil characterization. This adds a lot of value in proving the feasibility of utilizing waste Date pits oil for biofuel production. A novel heterogeneous catalyst (Mn@MgO-ZrO2) has been synthesized for improved biodiesel production. This catalyst has not been reported to be used for biodiesel production before.
The utilization of waste Date pits powder post oil extraction after its modification with Palladium and Platinum metals to be used as catalyst has not been reported before. Further on, synthesized catalysts have been used for hydrodeoxygenation of Date pits oil. Valorizing the glycerol obtained as a by-product from biodiesel production to fuel additive (solketal) is novel (no literature reported regarding this work). For the first time, sulphonated carbon catalyst has been synthesized from waste Date pits powder post oil extraction by simultaneous carbonization and sulphonation. Further on, the sulphonated carbon catalyst has been used for tertiary butylation of phenol.
