Biofuel, Bioenergy and Feed Valorization of By-Products and Residues from Hevea brasiliensis Cultivation to Enhance Sustainability

Abstract

In the latex production chain, rubber tree seeds (Hevea brasiliensis) represent an underutilized fraction with high potentialities, which can increase the sustainability of the whole process if rightly valorized. In the present study, the quality of all the fractions obtained from the rubber fruit were evaluated, with the aim to identify possible applications for their valorization with a circular economy perspective. Seeds from five different varieties of rubber tree were analyzed. Furthermore, a whole mass and energy balance was defined, which has allowed us to define hypothetical production scenarios. The obtained results show negligible differences among varieties. Shells and capsules have shown a composition similar to woody biomass, with high heating values (more than 16.5 MJ kg−1), low nitrogen content (below 0.5% on weight basis (w/w)) and reduced ash content (0.51% w/w and 1.90% w/w, respectively). Kernels were chemically extracted comparing two different solvents: n-hexane and ethanol. Both solvents showed similar extraction yields, i.e., 49% w/w and 46% w/w for n-hexane and ethanol, respectively. The resulting extraction flour was characterized by a high protein content (around 40% w/w) making it suitable for animal feeding. The rubber seed oil could be used in blends of different vegetable oils for biodiesel production. All this information is useful for improving the sustainability of the latex production chain and to assess the sustainability of possible bioenergy value chains.

Quality Assessment and Classification of Feedstock for Bioenergy Applications Considering ISO 17225 Standard on Solid Biofuels

“…Such relation between these parameters (hydrogen, carbon, oxidation state, energy released) is also confirmed in other studies [6,38]. The more hydrogen per carbon, the lower the oxidation state, and the more energy is released during the oxidation reaction.…”

“…The initial hypothesis is that a single group of biomasses should correspond to a set of relatively narrow and characterizing analytical parameters. The main parameters taken into consideration are the content of carbon, hydrogen, oxygen, moisture, ash (with a particular focus), chlorine, sulfur, nitrogen and gross calorific value [33][34][35][36][37][38][39][40][41][42][43]. The case study presents several points of novelty with respect to the literature.…”

Biofuel Production from Rubber Seeds by Pyrolysis Method using Natural Zeolite Catalyst

“…This result showed that the mix of seeds and shells was the most optimal raw material in yield. Therefore, the combination of rubber seed and rubber seed shell provides a higher yield of biofuel than using either of them alone because rubber seed shell has a low ash percentage and a heating value equivalent to virgin wood, making it an appealing attribute for a solid biofuel [30]. Rubber seed kernel is widely recognized for its oil content, with a 33.1 wt.% oil output that can potentially be used to produce biofuel [2].…”

Investigation of the Influence of Different Vegetable Oils as a Component of Blended Biofuel on Performance and Emission Characteristics of a Diesel Engine for Agricultural Machinery and Commercial Vehicles

“…Reductions in HC emissions of 14% [69], 14.3% [30], 11-17% [58], 17.5% [3], 22% [53], 30% [64], 31.8% [19], 50% [11], 55% [26], and 85.9-86.7% [35] have been experimentally achieved. However, when engine settings were retained the same as for DF operation, using blended fuel containing 20% of castor oil biodiesel or soybean oil biodiesel increased HC emissions by 16% and 18%, respectively, compared to DF [57].…”