https://gpj.ui.ac.ir/ Gas Processing Journal en daily 1 Sun, 01 Oct 2023 00:00:00 +0330 Sun, 01 Oct 2023 00:00:00 +0330 https://gpj.ui.ac.ir/article_29294.html The objective here is to assess the thermodynamic and environmental performance of Wankel engines, a distinctive internal combustion engine (ICE), by applying rotary design advantages. Unlike traditional reciprocating engines, Wankel engines due to their lower combustion chamber temperatures and pressure ratios exhibit unique emission profiles. Thermodynamic modeling through EES software is applied to simulate this Wankel engine’s operation and compare its performance with conventional four-stroke reciprocating engines. The innovations here are analyzing the combustion parameters impact, on the chamber temperature exceeding 1800 K, on reducing greenhouse gases like CO₂ and NO₂, and evaluating water or steam injection methods to balance NOx and CO emissions. The optimization strategies for emission reductions through hydrogen and biofuels are assessed here. These findings provide new insights into enhancing the efficiency and sustainability of Wankel engines, offering practical implications for the development of cleaner combustion technologies. https://gpj.ui.ac.ir/article_29295.html An industrial hydrogen production plant is simulated through methane steam reforming process. A heat-integrated bayonet tube reactor, the key feature of which is separating the furnace and reactor tube constitute the main component of this process. The plant is a complex unit inoperation, where off-gas streams for burner fuel, flue gas are consumed for heating the feed and producing steam, next to having a complex structure of hydrogen production reactor. The plant simulation is run through the Aspen HYSYS software, and the hydrogen production reactor is modeled through Matlab software. The results indicate good agreement with plant data at different capacities. The Mean Absolute Relative Error (MARE) percentage for the outlet flue gas temperature, a crucial factor in predicting hydrogen production is 5. The MARE for steam production is below 3%. For the water-gas shift reactor, the MARE for outlet mole fractions and temperature is below 10%. These findings underscore the model's potential for predicting the performance of an industrial-scale hydrogen production unit accurately. https://gpj.ui.ac.ir/article_29296.html Scientific discussions are gaining momentum on renewable energy, geothermal energy in specific. Researchers are seeking to propose different methods for energy storage systems that are more efficient and environment-friendly. The objective here is to propose an innovative approach where geothermal energy is consumed to fulfill different requirements first, and be stored in liquid hydrogen and consumed cold energy generated from geothermal sources through an absorption refrigeration cycle for pre-cooling, next. This liquid hydrogen is gasified before entering the liquefaction cycle. This multipurpose system produces hot water, freshwater, and power through geothermal energy. The geothermal flow enters the ammonia water absorption cooling unit, first, where its temperature is reduced, and enters the organic Rankine power generation unit equipped with a heat exchanger to produce hot water. The system is assessed by running energy, exergy, and economic analyses, with a focus on the hydrogen liquefaction cycle. The total estimated annual cost of the system is $1.62 million, with a minimum selling price of $2.96. The specific energy consumption in the multipurpose system is computed as 8.78 kWh p/kg of liquid hydrogen produced. https://gpj.ui.ac.ir/article_30277.html In this study, a novel venting system, referred to as the solar vent, is experimentally evaluated for its effectiveness in reducing gasoline evaporation from fuel storage tanks used in fuel dispensing stations. By leveraging the solar chimney effect, the study examines the influence of vent geometry on transient pressure behavior above the fuel surface and the resulting evaporative losses under laboratory conditions representative of practical operation. The experimental dataset analyzed in this work was previously reported in a related publication combined with numerical simulations. However, the present paper is exclusively devoted to a refined experimental interpretation, with emphasis on pressure stability and evaporation behavior. Two identical 220 L gasoline storage tanks were constructed as laboratory-scale models, one equipped with a conventional vent pipe and the other with the proposed solar vent. Both tanks were exposed to identical environmental conditions over a 17-day test period. The study focuses on comparing pressure fluctuations and evaporation losses between the two vent configurations. Experimental observations indicate that the solar vent maintains a slightly higher and more stable positive pressure above the gasoline surface compared to the conventional vent, which correlates with reduced evaporative losses. Under the specific laboratory conditions examined, the conventionally vented tank experienced approximately 3.5% fuel loss. In contrast, the tank equipped with the solar vent exhibited about 0.9% loss, corresponding to an approximate reduction of up to 75% in evaporation. These findings demonstrate the potential of the solar vent as a passive and effective strategy for mitigating fuel losses in gasoline storage tanks at the laboratory scale.