IMPROVING PERFORMANCE AND DEVELOPMENT OF TWO-STAGE RECIPROCATING COMPRESSORS

ABSTRACT The most troublesome part in the development of a compressor technology depends strongly on improvement of its performance. For this purpose, a performance characteristic evaluation of a twostage reciprocating compressor is carried out in this paper. The aims were to improve compressor performance by illustrating the effects of various parameters: primary air tank, compressor running time, background working condition, and air leakage. The effect of each parameter was compared with the normal performance condition and, in turn, it was demonstrated the most/least important parameters on the performance. The parameters were measured using three techniques: the digital display unit, instruments fixed on system layout, and a PC-data acquisition system. The experiment addressed some factors that led to the inefficient performance of the compressed air system and cause energy losses. The results advocate the optimal time for starting each stage of the two-stage compressors. This work, in addition, may give the insight for the development of the design of multistage compressors and presents some key design parameters

Isotherm, kinetic and modeling studies

Funding Information: Funding: The Deanship of Scientific Research at King Khalid University General Research Project under the grant number (R.G.P.2/138/42) and Taif University researchers supporting project number (TURSP–2020/157), Taif University, Taif, Saudi Arabia. Funding Information: Acknowledgments: The co‐author Ali E. Anqi would like to extend his appreciation to the Deanship of Scientific Research at King Khalid University for the support he received through General Re‐ search Project under the grant number (R.G.P.2/138/42). This work was supported by Taif Univer‐ sity researchers supporting project number (TURSP–2020/157), Taif University, Taif, Saudi Arabia. The first author was thankful to the Directorate of Minorities, Govt. of Karnataka for providing PhD fellowship to conduct the research. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The first-ever use of halloysite nanotube (HNT), a relatively low-cost nanomaterial abun-dantly available with minor toxicity for removing brilliant green dye from aqueous media, is re-ported. The factors affecting adsorption were studied by assessing the adsorption capacity, kinetics, and equilibrium thermodynamic properties. All the experiments were designed at a pH level of around 7. The Redlich-Peterson isotherm model fits best amongst the nine isotherm models studied. The kinetic studies data confirmed a pseudo model of the second order. Robotic investigations pro-pose a rate-controlling advance being overwhelmed by intraparticle dispersion. The adsorbent fea-tures were interpreted using infrared spectroscopy and electron microscopy. Process optimization was carried out using Response Surface Methodology (RSM) through a dual section Fractional Fac-torial Experimental Design to contemplate the impact of boundaries on the course of adsorption. The examination of fluctuation (ANOVA) was utilized to consider the joined impact of the boundaries. The possibilities of the use of dye adsorbing HNT (“sludge”) for the fabrication of the composites using plastic waste are suggested.publishersversionpublishe

A recent study on remediation of direct blue 15 dye using halloysite nanotubes

R.G.P.2/138/42 TURSP–2020/157A set of lab‐scale experiments were designed and conducted to remedy Direct Blue 15 (DB15) dye using nontoxic halloysite nanotubes (HNT) with the view to be utilized in a textile industrial effluent (TIE). The DB15 adsorbed‐HNT “sludge” was used as a reinforcing agent and plas-tic waste to fabricate the composite. To advance the knowledge and further understand the chemical phenomena associated with DB15 adsorption on HNT, different factors like pH value, adsorbate initial concentration, adsorbent dosage, and temperature on the composite were affected experi-mentally tested. To estimate the adsorption capacity of HNT, nine isotherm models were applied, and it was identified that the Brouers–Sotolongo adsorption isotherm model represented the best accuracy for predicting the adsorption behavior of the HNT. Likewise, the pseudo‐second‐order reaction was the predominant mechanism for the overall rate of the multi‐step dye adsorption pro-cess. Additionally, it was demonstrated that the mass transfer during the process is diffusion‐con-trolled, and thermodynamic assessments showed that the process is physisorption.publishersversionpublishe

Experimental investigation on compression ignition engine powered with pentanol and thevetia peruviana methyl ester under reactivity controlled compression ignition mode of operation

In the current study, an effort is carried out to study the influence of pentanol as low reactive fuel (LRF) along with diesel and Thevetia peruviana methyl ester (TPME) as high reactive fuels (HRF) in reactivity controlled compression ignition (RCCI) engine. The experiments are conducted on dual fuel engine at 50% load for RCCI mode of operation by varying pentanol percentage in injected fuels. The results revealed that RCCI mode of operation at 10% of pentanol in injected fuels exhibited higher brake thermal efficiency (BTE) of 22.15% for diesel and pentanol fuel combination, which is about 9.1% and 27.3% higher than other B20 and pentanol, B100 and pentanol fuel combinations respectively. As the percentage of pentanol increased in injected fuels, hydrocarbon (HC) and carbon monoxide (CO) emissions are increased while nitrogen oxide (NOx) and smoke emissions are decreased. Among various fuel combinations tested diesel and pentanol fuel combination gives lower HC, CO and smoke emissions and higher NOx emissions. At 10% pentanol in injected fuels, the highest heat release rate (HRR) and in-cylinder pressure are found for diesel and pentanol fuel combinations compared with other fuels

Sustainable adsorption method for the remediation of malachite green dye using nutraceutical industrial fenugreek seed spent

Nutraceutical industrial fenugreek seed spent (NIFGS), a relatively low-cost material abundantly available with nearly negligible toxicity for the bioremediation of malachite green (MG) dye from aqueous media, is reported. Studies on the various parameters affecting the adsorption capacity of NIFGS were carried out to evaluate the kinetics and the equilibrium thermodynamics. All the experiments were designed at about pH 7. The adsorption isotherm model proposed by Langmuir fits better than the Freundlich isotherm model. Kinetic study data confirms the viability of pseudo-second-order model. Calculated thermodynamic factors suggest that the adsorption phenomenon is endothermic, almost instantaneous, and physical in nature

Dual and Ternary Biofuel Blends for Desalination Process: Emissions and Heat Recovered Assessment

Desalination using fossil fuels is so far the most common technique for freshwater production worldwide. However, such a technique faces some challenges due to limited fossil fuels, high pollutants in our globe, and its high energy demand. In this study, solutions for such challenges were proposed and investigated. Renewable biofuel blends were introduced and examined as energy/sources for desalination plants and, in turn, reduced dependency on fossil fuels, enhanced pollutants, and recovered energy for desalinations. Eight different blended biofuels in terms of dual and ternary blend approaches were investigated. Results displayed that dual and ternary blends of gasoline/n-butanol, gasoline/isobutanol, gasoline/n-butanol/isobutanol, gasoline/bioethanol/isobutanol, and gasoline/bioethanol/biomethanol were all not highly recommended as energy sources for desalination units due to their low heat recovery (they showed much lower than the gasoline, G, fuel); however, they could provide reasonable emissions. Both gasoline/bioethanol (E) and gasoline/biomethanol (M) provided high heat recovery and sensible emissions (CO and UHC). Gasoline/bio-acetone was the best one among all blends and, accordingly, it was upper recommended for both heat recovery and emissions for desalination plants. In addition, both E and M were recommended subsequently. Concerning emissions, all blends showed lower emissions than the G fuel in different levels

Modeling of Pulverised Wood Flames

The aim of the current work was at development and validation of modeling tools for simulation of pulverised wood flames in furnaces and study how different factors influence on such flames. The numerical model involves different sub-models for the physo-chemical processes, such as, two-phase flow motion, drying, devolatilization and shrinkage of particles, the formation and oxidation of volatile, tar and char, turbulence-chemistry interaction, turbulence-radiation interaction, etc. Because of the complexity of such flames, the work here is divided into different stages. In the first stage, modeling the motion of pulverised wood particles in turbulent flows is carried out. This includes addressing the following open questions: how do highly anisotropic and typically non-spherical particles behave in turbulent flows; how are the particle projected area and orientations changed during particle tracing; how is the interaction between the particles and the flow field (turbulence). In the second stage, the conversion of pulverised wood particles in combustion conditions is extensively studied. Modelling of different processes during the conversion is investigated. More attention is paid upon the devolatilization process since it is the most dominating one during the thermal degradation processes. The devolatilization kinetics for pulverised wood particles in combustion conditions is studied, including the evaluation and determination of devolatilization mechanism and devolatilization rate constants. In the third stage, the effect of moisture and volatile releases during thermal degradation on the motion of pulverised wood particles is studied. Since the fiber structure in the wood particles is anisotropic; the release of gasses is not isotropic along the particle surface. The particle is then subjected to a force that we may refer to ?rocket? force, since the physical process resembles that of rocket propulsion. This new phenomenon is modeled and validated during this stage. In addition, the effect of rocket force on the particle velocity, particle distribution and the combustion processes is investigated. In the fourth stage, the sub-models studied in the previous stages are coupled together with supplementary sub-models, such as oxidation of volatile, tar and char, turbulence-chemistry interaction and turbulence-radiation interaction, to simulate the pulverised wood flames in a vertical furnace. Different flame sub-models together with required governing equations are all integrated to a CFD code, developed previously at LTH. The solid-gas coupling is done here using the Eulerian/Lagrangian coupling approach. From this work the basic structures of pulverised wood flames are identified. It was shown that pulverised wood flames have strong similarity and difference as compared to gaseous flames. Similar to the gaseous premixed flames, the pulverised wood flames consist of distinct zones ? preheat zone, drying-devolatilization zone, oxidation zone and post-flame zone. The mechanism of heat transfer to the preheat zone of pulverised wood flames is however different from the gas flames. The structure of pulverised wood flames is not only a property of the fuel/air mixture itself, but also it depends on the combustor configuration. It was shown that pulverised wood flames are rather sensitive to the physical parameters such as particle size and shape, heat capacity of particles, fuel feeding rate and shrinkage process

Investigations on the effects of ethanol–methanol–gasoline blends in a spark-ignition engine: Performance and emissions analysis

This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol–methanol–gasoline blends. The test results obtained with the use of low content rates of ethanol–methanol blends (3–10 vol.%) in gasoline were compared to ethanol–gasoline blends, methanol–gasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was fueled with ethanol–methanol–gasoline blends, the concentrations of CO and UHC (unburnt hydrocarbons) emissions were significantly decreased, compared to the neat gasoline. Methanol–gasoline blends presented the lowest emissions of CO and UHC among all test fuels. Ethanol–gasoline blends showed a moderate emission level between the neat gasoline and ethanol–methanol–gasoline blends, e.g., ethanol–gasoline blends presented lower CO and UHC emissions than those of the neat gasoline but higher emissions than those of the ethanol–methanol–gasoline blends. In addition, the CO and UHC decreased and CO2 increased when ethanol and/or methanol contents increased in the fuel blends. Furthermore, the effects of blended fuels on engine performance were investigated and results showed that methanol–gasoline blends presents the highest volumetric efficiency and torque; ethanol–gasoline blends provides the highest brake power, while ethanol–methanol–gasoline blends showed a moderate level of volumetric efficiency, torque and brake power between both methanol–gasoline and ethanol–gasoline blends; gasoline, on the other hand, showed the lowest volumetric efficiency, torque and brake power among all test fuels

Performance and emissions analysis on using acetone–gasoline fuel blends in spark-ignition engine

In this study, new blended fuels were formed by adding 3–10 vol. % of acetone into a regular gasoline. According to the best of the author's knowledge, it is the first time that the influence of acetone blends has been studied in a gasoline-fueled engine. The blended fuels were tested for their energy efficiencies and pollutant emissions using SI (spark-ignition) engine with single-cylinder and 4-stroke. Experimental results showed that the AC3 (3 vol.% acetone + 97 vol.% gasoline) blended fuel has an advantage over the neat gasoline in exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency by about 0.8%, 2.3%, 1.3%, 0.45% and 0.9%, respectively. As the acetone content increases in the blends, as the engine performance improved where the best performance obtained in this study at the blended fuel of AC10. In particular, exhaust gases temperature, in-cylinder pressure, brake power, torque and volumetric efficiency increase by about 5%, 10.5%, 5.2%, 2.1% and 3.2%, respectively, compared to neat gasoline. In addition, the use of acetone with gasoline fuel reduces exhaust emissions averagely by about 43% for carbon monoxide, 32% for carbon dioxide and 33% for the unburnt hydrocarbons. The enhanced engine performance and pollutant emissions are attributed to the higher oxygen content, slight leaning effect, lower knock tendency and high flame speeds of acetone, compared to the neat gasoline. Finally the mechanism of acetone combustion in gasoline-fueled engines is proposed in this work; two main pathways for acetone combustion are highlighted; furthermore, the CO, CO2 and UHC (unburnt hydrocarbons) mechanisms of formation and oxidation are acknowledged. Such acetone mechanism is employed for further understanding acetone combustion in spark-ignition engines

Modelling of pulverised wood combustion: a comparison of different models

Several models have been proposed in the literature for numerical simulations of pulverised wood drying, pyrolysis, gasification and combustion processes. These models are based on different assumptions and they yield fairly different results. In the present study a pulverised wood flame in a laboratory vertical furnace is chosen as the test case to evaluate the different sub-models including, drying, devolatilisation and shrinkage processes. Numerical results from a base model are first compared with experimental data. Sensitivity of the numerical results to various model parameters and fuel variations such as moisture content, gas compositions, devolatilisation rate constant and shrinkage are examined based on the base model, using the 'changing one separate factor at a time' (COST) approach