Methanol to olefins (MTO) is an essential process that produces olefins from both renewable and fossil fuels resources. Chabazite (CHA) is an efficient catalyst for MTO process due to its distinct properties that promote light olefins (i.e., ethylene and propylene) production. Herein, we report a series of chabazite-based catalysts (OSDA-free with enhanced textural properties) that facilitate the MTO reaction. The synthesized CHA was modified by steam injection (CHA-S), acid treatment (CHA-A), steam and acid treatment (CHA-SA), and metal incorporation (CHA-SA (Mg), CHA-SA (Ca), and CHA-SA (Ba)). The catalysts were characterized by several characterization techniques. The structure was investigated using X-ray diffraction (XRD) and nuclear magnetic resonance, while the morphology and physical properties were studied by field emission scanning electron microscopy (FE-SEM), N2 adsorption/desorption, and ammonia temperature-programmed desorption (NH3-TPD). The catalysts were evaluated at 450 °C until deactivation. CHA modified by only acid treatment showed higher selectivity to olefins from ca. 92 to 95 wt.% but suffered quick deactivation. CHA modified with both steam and then acid treatment was more stable in the MTO process.

The global energy demand is expected to increase by 30% within the next two decades. Plastic thermochemical recycling is a potential alternative to meet this tremendous demand because of its availability and high heating value. Polypropylene (PP) and polyethylene (PE) are considered in this study because of their substantial worldwide availability in the category of plastic wastes. Two cases were modeled to produce hydrogen from the waste plastics using Aspen Plus®. Case 1 is the base design containing three main processes (plastic gasification, syngas conversion, and acid gas removal), where the results were validated with the literature. On the other hand, case 2 integrates the plastic gasification with steam methane reforming (SMR) to enhance the overall hydrogen production. The two cases were then analyzed in terms of syngas heating values, hydrogen production rates, energy efficiency, greenhouse gas emissions, and process economics. The results reveal that case 2 produces 5.6% more hydrogen than case 1. The overall process efficiency was enhanced by 4.13%. Case 2 reduces the CO2 specific emissions by 4.0% and lowers the hydrogen production cost by 29%. This substantial reduction in the H2 production cost confirms the dominance of the integrated model over the standalone plastic gasification model.

Recently, Liquified petroleum gas (LPG) attracts wide applications due to its high heating value and clean combustibility. An innovative approach to synthesis of LPG from syngas was established based on Fisher-Tropsch (F-T) technology. However, the conversion and selectivity are generally low with the classical catalysts. The hybrid system of methanol and zeolitebased catalyst was established as a potential approach to promote such a process. To strongly overcome the large demand of LPG and grasp the research work in this subject, a comprehensive review became necessary. LPG is basically produced from syngas through the direct method, where most recent studies lay on, and the indirect or semi direct approach. There were several factors affecting the process performance, which mainly are the reaction temperature, reaction pressure, type of the hybrid catalyst, carbon monoxide to hydrogen ratio, mixture flow rate, and time-on-stream of the reaction. The most common reaction conditions reported in the literature are 260-400 °C, 10-50 bars and H 2 to CO ratio of 2. However, the most important parameter considered was the catalyst, which is a key factor of interest. The two main issues controlling the catalyst performance were the synergetic effect between the two hybridized catalysts and the used type of zeolite. It was perceived that the higher the zeolite membered rings the better the LPG selectivity (i. e., BEA, and USY provided the higher LPG production rate).

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The worldwide demand for energy is increasing significantly, and the landfill disposal of waste tires and their stockpiles contributes to huge environmental impacts. Thermochemical recycling of waste tires to produce energy and fuels is an attractive option for reducing waste with the added benefit of meeting energy needs. Hydrogen is a clean fuel that could be produced via the gasification of waste tires followed by syngas processing. In this study, two process models were developed to evaluate the hydrogen production potential from waste tires. Case 1 involves three main processes: the steam gasification of waste tires, water gas shift, and acid gas removal to produce hydrogen. On the other hand, case 2 represents the integration of the waste tire gasification system with the natural gas reforming unit, where the energy from the gasifier-derived syngas can provide sufficient heat to the steam methane reforming (SMR) unit. Both models were also analyzed in terms of syngas compositions, H 2 production rate, H 2 purity, overall process efficiency, CO 2 emissions, and H 2 production cost. The results revealed that case 2 produced syngas with a 55% higher heating value, 28% higher H 2 production, 7% higher H 2 purity, and 26% lower CO 2 emissions as compared to case 1. The results showed that case 2 offers 10.4% higher process efficiency and 28.5% lower H 2 production costs as compared to case 1. Additionally, the second case has 26% lower CO 2 -specific emissions than the first, which significantly enhances the process performance in terms of environmental aspects. Overall, the case 2 design has been found to be more efficient and cost-effective compared to the base case design.