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Production of liquefied natural gas (LNG) requires a huge amount of energy, therefore Enhancing the plant's energy efficiency is one of the most significant issues in a natural gas liquefaction facility. This study aims to improve the energy efficiency of the propane pre-cooling mixed refrigerant (C3MR) process by two approaches. first by minor structural modification of the existing cycle to reduce the shaft power of the compressor as it is the major energy-consumption unit in LNG plants by about 2.2 (MW/MTPA LNG) that results in increasing coefficient of performance (COP) of the refrigeration cycle. The Second approach investigates the feasibility of applying a hybrid modification of the AP-X process, designed by Air Products and Chemicals Incorporation (APCI), and a comparative study between conventional and modified cycles. The case study is a plant existing in Egypt and it is simulated by Aspen HYSYS version 11. The simulation results show two advantages after implementation of cycle modification: a reduction in total specific power by 12.5% by reduction in the flow rate of propane and mixed refrigerant by 26.1% and 40.8 % respectively. Another feature is increasing LNG production capacity to about 8 MTPA. [ABSTRACT FROM AUTHOR]

The present work aims to retrofit an existing Egyptian oilfield plant to improve desalter performance and reduce the power of crude oil shipping pumps. In this work, waste heat in disposed water that represents a value is used in heating brackish water injected over desalter and in heating crude oil before shipping. ASPEN HYSYS version 11 simulation software was used. The retrofit of the considered oilfield plant is based on the implementation of two new heat exchangers to recover waste heat in the disposed water. The results showed that using waste heat to heat the brackish water in the desalter from 30 °C to 71.11 °C will increase the operating temperature of the desalter and thus increase the sedimentation and separation rate. On the other hand, using waste heat in heating the crude oil before shipping from 37.78 °C to 71.11 °C reduces the oil viscosity from 1.536 cSt to 0.9735 cSt. Reducing the viscosity of the crude oil will reduce the pressure drop of the shipping pumps, and therefore the power required to pump the oil will be reduced. The presented retrofit design can be used as a guide in upgrading existing plants and plants under the design phase. [ABSTRACT FROM AUTHOR]

Flares are safety systems designed to protect site facilities, people, and environmental pollution. The vented gas from equipment is mainly used to control the pressure of the processes. In oil companies, the production capacity of wells decreases over time due to well depletion. To maintain productivity, a new compression project is being constructed to improve well recovery with lower reservoir production and pressure. For such the new compression it is required to create a vent system for it to relieve pressure in case of normal and emergency conditions. In this work, two scenarios are proposed to connect the venting system of the new project to the existing flare systems. These two scenarios are staggered and conventional blowdowns. The study of the two proposed scenarios was based on the allowable design capacity of the current flare systems. In addition, a comparison was made between the two proposed scenarios and two other scenarios from the literature. The results showed that the conventional blowdown scenario is the most effective to meet the current blowdown criteria and existing design requirements. [ABSTRACT FROM AUTHOR]

The extensive use of antibiotics created two of the biggest hazards to global health in the twenty-first century, namely, antibiotic residues and antimicrobial-resistant (AMR) bacteria. This research seeks to scrutinize the correlation between antibiotic residues and antibiotic- resistance genes (ARGs) of Staphylococcus aureus (S. aureus). 120 raw milk samples were systematically procured from diverse sources, involving dairy farms (40), farmers' houses (20), dairy shops (40), and street vendors (20). These samples underwent thorough screening for subclinical mastitis (SCM), S. aureus counts, and antibiotic residues. Coagulase-positive S. aureus (CPSA) was isolated and quantified in 15% (18/120) of the samples. Among these isolates, 94.4% displayed resistance to penicillin, 5.6% to trimethoprim, 22.2% to gentamycin, ofloxacin, and erythromycin, while 27.8% exhibited resistance to vancomycin. PCR amplification of 23S rRNA confirmed the identity of all tested strains as S. aureus (100%), which were then found to harbor ARGs associated with β-lactams (blaZ gene), aminoglycosides (aac(&)aph (2'') gene), and vancomycin (Van A gene). Milk samples that underwent reverse-phase high-performance liquid chromatography (HPLC) revealed residues of oxytetracycline, amoxicillin, and gentamicin at rates of 8.3%, 1.7%, and 6.7%, respectively, with maximum levels exceeding the European Union Maximum Residue Limits (EU-MRL) (2010). The ARGs related to multidrug-resistant (MDR) S. aureus were identified in 40% (8/20) of milk samples contaminated with antibiotic residues. [ABSTRACT FROM AUTHOR]

This study aimed to isolate and enumerate Nocardiae from the examined raw milk samples. 240 random milk samples were collected from cows, buffaloes, sheep and goats from different localities in Assiut city- Egypt. The incidences of Nocardia spp. were 47.8, 43.3, 53.3 and 66.7%with average counts of 3.8 x104, 4.5x104, 1.4x104 and 7.6x103/CFUmL of the examined samples, respectively. Pathogenicity of the isolates was also studied. N. otitidiscavarium and N. brasiliensis caused sudden death of rats while,N. farcinica and N. carnea strains were non pathogenic. Other species caused several lesions. It was concluded from the study that,Nocardia species are existed in retailed and fresh milk of different farm animals. Most of the isolated strains were highly pathogenic to rats. Consequently, preventive measures should be taken to protect consumers from being infected. [ABSTRACT FROM AUTHOR]