The hydrocracking of long paraffins in the presence of sulfur and aromatic impurities using Pt–Pd/WO₃–ZrO₂ was assessed. The catalysts were tested for n-hexadecane hydrocraking in the presence and absence of several poisons, benzothiophene, quinolein, carbon disulfide, benzene, and naphthalene. At small impurity levels, aromatics are beneficial for the hydrocracking of long paraffins because they increase the liquid yield and reduce the cracking to light gases. Sulfur compounds were strong poisons of the activity. Benzothiophene was the strongest, producing the highest decline in activity and being more strongly chemisorbed than basic quinolein. Sulfur poisoning drastically affected the hydrocracking activity, indicating that acid isomerization cracking on WO₃–ZrO₂ follows a bifunctional mechanism with a big influence of the metal function. Incorporation of Pd to Pt/WO₃–ZrO₂ reduced the sulfur poisoning, with Pt–Pd (3:1)/WO₃–ZrO₂ being the best catalyst for stable hydrocracking of long paraffins in the presence of sulfur. This catalyst retained most of the activity of the Pt/WO₃–ZrO₂ parent material while being less affected by sulfur.

The end-of-life management of plastic represents a significant environmental challenge, largely due to its limited use, low biodegradability, and high volume of disposed material, in the order of 400 million tonnes by 2019. Several types of polymers can be recycled by mechanical means, but some others, like plastics, sometimes require chemical methods for their reuse. In this context, gasification is one of the most promising chemical recycling techniques. Gasification is a thermochemical process performed at moderate temperatures of work (800–1100 °C) that converts carbonaceous materials into rich hydrogen gas, which can be used for energy obtention or the Fisher–Tropsch process. However, this procedure can also produce undesirable by-products like tar and char. The products’ composition and relative quantities are highly dependent on the overall process configuration and the input fuel. The current study evaluates the catalytic gasification of the most common plastic waste, seeking to obtain higher gas yields and syngas with high energy. The text focuses on the current state of development and recent advances in various publications over the last fifteen years, with emphasis on thermoplastics and thermosets. The search showed that temperatures, the type of fluidizing gas, and the catalyst have a major influence on the quality of the obtained gas. Optimal gasification conditions, such as temperatures between 600 and 900 °C, depending on the plastic feedstock, steam-to-feedstock ratios > 1, the appropriate selection of a gasifying agent according to gas requirements and energy optimization, and the composition and location of the catalyst in the system (in situ, in the reactor, or ex situ), are identified as critical for maximizing H₂ and CO production and minimizing tar. Finally, we provide summaries of the last advanced patent in the field, where the main focus appears to be feedstock pretreatment intended to ensure handling feasibility due to the variety of plastic wastes.

WO3-ZrO2 catalysts promoted with Pt and Pd were tested as paraffin isomerization catalysts using n-hexane as model compound. Sulfur and amine poisoning and regeneration tests were used to assess the impact of the addition of Pt and Pd on the deactivation resistance and regenerability. Pt and PtPd catalysts were the most active for n-hexane isomerization. The low activity of the Pd catalyst was attributed to poor Pd metal properties when supported over WO3-ZrO2 and to a decrease of the number of BrQnsted acid sites. PtPd was the only catalyst capable of full regeneration after S poisoning. Amine poisoning completely supressed the isomerization activity and the original activity could only be restored by calcination and reduction

The management of solid waste and the supply of energy are two of the most important environmental problems of our time. Projections indicate that by 2050, the global demand for electrical energy is expected to increase by 35% and the amount of solid waste generated to increase by 45%. In this context, polymeric waste materials such as biomass and plastics can be valorised through thermochemical processes for the generation of energy. Gasification, which converts carbonaceous materials into syngas, tar, and char, is one of the most promising recycling technologies. The composition and relative quantities of the products are influenced by the process configuration, operating parameters, and the type of fuel used. Tar removal is facilitated by adding specific catalysts to the process. The co-processing of biomass and plastics in the gasification process, called co-gasification, improves the gas yield and reduces solid residues. This review evaluates catalytic and non-catalytic co-gasification of biomass waste and non-biodegradable plastics, with a focus on syngas production and its energy potential.

The possibility of regenerating the solvent of extraction units by cyclic adsorption was analyzed. This combination seems convenient when extraction is performed with a high solvent-to-impurity ratio, making other choices of solvent regeneration, typically distillation, unattractive. To our knowledge, the proposed regeneration scheme has not been considered before in the open literature. Basic relations were developed for continuous and discontinuous extraction/adsorption combinations. One example, deacidification of plant oil with alcohol, was studied in detail using separate experiments for measuring process parameters and simulation for predicting performance at different conditions. An activated carbon adsorbent was regenerated by thermal swing, making cyclic operation possible. When extracting the acid with methanol in a spray column, feed = 4 L min⁻¹, solvent = 80 L min⁻¹, feed impurity level 140 mmol L⁻¹, and extract concentration 7.6 mmol L⁻¹, the raffinate reaches a purity of 1.2 mmol L⁻¹, the solvent being regenerated cyclically in the adsorber (364 kg) to an average of 0.7 mmol L⁻¹. Regeneration of the solvent by cyclic adsorption had a low heat duty. Values of 174 kJ per litre of solvent compared well with the high values for vaporization of the whole extract phase (1011 kJ L⁻¹).