Eid M Al Mutairi

This work proposes and statistically analyzes a hexagonal-shaped hollow-core photonic crystal fiber-based edible oil sensor in the terahertz (THz) range. The suggested sensor’s performance was assessed by means of Comsol Multiphysics, a finite element method-based commercial tool. The simulation results demonstrate that the suggested sensor has more than 99% relative sensitivity for different types of edible oils at 1.6 THz under ideal geometric conditions. Furthermore, the suggested sensor exhibits low confinement loss, high numerical aperture and effective area at optimal geometry and operational conditions. The proposed sensor is realizable using conventional production procedures and its superior sensing qualities may make it a key component of real-world oil detection systems.

The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions, our environment conditions might be affected, necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore, this study analyzed and examined it critically. In this study, two different routes for the produc-tion of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes, a brief comparison was made between the two routes of hydrogen production in terms of their CO₂ emissions, en-ergy efficiency, energy consumption, and environmental and economic impacts. In this study, the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8%, which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen, which was almost 9% lower than that of Case I. In terms of the environmental analysis, both cases had comparably low carbon emissions of around 8.3 kg of CO₂/kg of hydrogen produced; with such high purity, the hydrogen could be used for production of other products further downstream or for industrial applications.

In this study, ultrasonication-assisted calcium carbonate scale inhibition was investigated compared with a commercial antiscalant ATMP (amino tris(methyl phosphonic acid)). The effects of varying ultrasound amplitude, pH, and inhibition duration were evaluated. The inhibition of calcium carbonate scale formation was measured based on the concentration of calcium in the solution after subjecting to different conditions. Scale deposits were also characterized using scanning electron microscopy and X-ray diffraction spectroscopy. Inhibition of scale formation was supported at a pH of 7 for an ultrasound amplitude of 150 W. A 94% calcium carbonate inhibition was recorded when the experiment was carried out with ultrasonication. The use of 5 mg/L ATMP achieved a 90% calcium carbonate inhibition of ATMP. The result of the characterization revealed that the morphology of the crystals was unaffected by ultrasonic irradiation. Sample treatment was performed with two different membranes to evaluate the calcium carbonate deposition, and data reveals that, at identical conditions, ultrasonication provides less deposition when compared to the control experiments.

Asphaltene aggregation is one of the biggest problems in the oil and gas industry for both upstream and downstream processes. It called the cholesterol of crude oil since it can deposit on the reservoirs pores and block it. It can also plug the production tubes and pipelines which could cost millions of dollars. One of the solutions is adding different chemicals such as asphaltene dispersants (ADs) or asphaltene inhibitors (AIs). ADs reduce asphaltene particle size which will keep them in the crude while AIs prevent the asphaltene aggregation by shifting the onset pressure of asphaltene. In this paper, three different asphaltene inhibitors were tested and investigated thoroughly with different concentrations for heavy Arabian crude oil. Several tests were performed: asphaltene inhibitors efficiency was tested using laser scanner analysis and asphaltene stability was investigated by using spot test method and asphaltene solubility class index. The results showed that the Arabian crude oil has a high asphaltene content and it reasonably stable. Two of the inhibitors (SF-1742 and AI-410) have showed better efficiency than the third inhibitor (AI108) in the inhibitors efficiency test with low optimum concentration. Introduction Asphaltene is a crude oil component that is soluble in toluene and benzene but insoluble in n-alkane with low molecular weights (Balson et al., 2001). It can cause an enormous impact on the economics of the oil production by reducing the productivity of the wells and plugging the production facilities (Kelland, 2014). The asphaltene problem become more important due to the following reasons: deep reservoirs that contain heavy oil with high asphaltene content started to be important to the industry due to the depletion of the conventional ones and most oil fields tend to use the enhanced oil recovery methods which help in increasing the asphaltene deposition (Shadman et al., 2016). Poly-condensed aromatic structures, polar components and salt are the contents of the asphaltene core (Balson et al., 2001). Resins attached to the core of asphaltene stabilized the asphaltene particles and keep them suspended in the crude. If any disturbance occur to that equilibrium, asphaltene will start to agglomerate and deposit (Abedini et al., 2011). Asphaltene are destabilized by different factors such as: change in pressure, change in temperature, change in composition, pH-change, oxidation of resin, etc. (Balson et al., 2001). There are several methods that can be used to inhibit and remedy the asphaltene problem include chemical additives, mechanical techniques, thermal techniques, biochemical techniques, etc. (Ayyaswami, 2014; Lightford et al., 2008; Yarranton, 2000). Chemical additives is one of the most effective and low cost technique compared to other methods (Joonaki et al., 2017; Trbovich and King, 1991). There are two types of chemicals that can be used: asphaltene inhibitors (AIs) and asphaltene dispersants (ADs). AIs work by increasing the stability of the asphaltene where the ADs disperse the agglomeration and keep the asphaltene suspended in the oil (Joonaki et al., 2017; Kelland, 2014). One of the problems that associated with the chemical additives is that they are oil specific which means many tests must be done in the lab before choosing the chemical that will be used (Kelland, 2014). There are numerus methods that have been used in the industry to examine the performance of the inhibitors including light scattering method, filtration method, ultraviolet-visible spectrophotometry and spectroscopy technique (Andersen, 1999; Fahim et al., 2001; Hammami et al., 2000; Yen et al., 2001).

The objective of this paper is to present the study and analysis of the energy saving improvement for the NGLs Direct-Splitter-Direct fractionation sequence plant by using driving force method. To perform the study and analysis, the energy efficient distillation columns (EEDCs) methodology is developed. Basically, the methodology consists of four hierarchical steps; Step 1: Existing Sequence Energy Analysis, Step 2: Optimal Sequence Determination, Step 3: Optimal Sequence Energy Analysis, and Step 4: Energy Comparison. The capability of this methodology is tested in designing an optimal energy efficient direct-splitter-direct sequence of NGLs fractionation unit. The results show that the maximum of 10.62 % energy reduction was able to achieve by changing the sequence suggested by the driving force method. It can be concluded that, the sequence determined by the driving force method is able to reduce energy used for a NGLs fractionation. All of this findings show that the methodology is able to design energy efficient for NGLs fractionation sequence in an easy, practical and systematic manner.