Fuel production using membrane reactors: a review

Population growth has led to higher consumption of fossil fuel, and subsequently to a major increase of greenhouse gases emissions to the atmosphere, thus inducing global warming. Fossil fuel supplies are depleting, and the price of these fuels is increasing. Moreover, there are concerns about related emissions of toxic pollutants such as sulphur dioxide and aromatic hydrocarbons. Here, we review alternative fuel technologies. We focus on how membrane reactors improve the existing production processes of renewable fuels. Advantages and environmental benefits of membrane reactors are compared to the conventional techniques. Membrane reactors have been applied successfully to improve biodiesel, hydrogen and Fischer–Tropsch synthesis. Membranes help the conversion of products, whilst shifting the equilibrium of the reaction and reducing undesired by-products. Membrane reactors also overcome immiscibility issues that hinder conventional reactor processes. Overall, membrane reactors reduce cost and energy needed for the treatment of wastewater from fuel production

Process Simulation Modeling of the Linear Low-Density Polyethylene Catalytic Pyrolysis in a Fluidized Bed Reactor

In this work, a comprehensive process simulation was developed to study and predict the pyrolysis of linear low-density polyethylene (LLDPE) in a fluidized bed reactor (FBR). The comprehensive simulation operated at 600 and 700 °C to investigate the pyrolytic oil and wax yields. These products were chosen as they mimic fuel range products available as a renewable fuel and energy source. The results showed that the oil yield decreased from 600 to 700 °C. This is because of an increase in the polyolefin polymer matrix’s vibration leading to an increase in temperature and absorbed thermal energy. In addition, there is a higher gas yield produced and negligible wax formation at 700 °C, which is beneficial in controlling accrued plastic waste (PW), of which polyethylene (PE) represents a vast proportion of via thermo-chemical conversion (TCC) technologies. The detailed process simulation was compared with experimental data under the same technology and operating conditions, and it was found that less than 10% discrepancy was observed between the two sets of data, suggesting a good validation between the two studies. Further studies showed that the diesel fuel lumped hydrocarbon (HC) range (C10-C19) was between 40 and 63% in the pyrolysis oil yield obtained. Moreover, the temperature profiles and fluidized bed distributor parameters were compared and investigated. The current simulation has proven that it can successfully predict the pyrolysis of LLDPE in an FBR

Process Simulation Modelling of the Catalytic Hydrodeoxygenation of 4-Propylguaiacol in Microreactors

A process simulation model was created using Aspen Plus to investigate the hydrodeoxygenation of 4-propylguaiacol, a model component in lignin-derived pyrolysis oil, over a presulphided NiMo/Al2O3 solid catalyst. Process simulation modelling methods were used to develop the pseudo-homogeneous packed bed microreactor. The reaction was conducted at 400 °C and an operating pressure of 300 psig with a 4-propylguaiacol liquid flow rate of 0.03 mL·min−1 and a hydrogen gas flow rate of 0.09 mL·min−1. Various operational parameters were investigated and compared to the experimental results in order to establish their effect on the conversion of 4-propylguaiacol. The parameters studied included reaction temperature, pressure, and residence time. Further changes to the simulation were made to study additional effects. In doing so, the operation of the same reactor was studied adiabatically, rather than isothermally. Moreover, different equations of state were used. It was observed that the conversion was enhanced with increasing temperature, pressure, and residence time. The results obtained demonstrated a good model validation when compared to the experimental results, thereby confirming that the model is suitable to predict the hydrodeoxygenation of pyrolysis oil

CO2 capture using membrane contactors: a systematic literature review

With fossil fuel being the major source of energy, CO2 emission levels need to be reduced to a minimal amount namely from anthropogenic sources. Energy consumption is expected to rise by 48% in the next 30 years, and global warming is becoming an alarming issue which needs to be addressed on a thorough technical basis. Nonetheless, exploring CO2 capture using membrane contactor technology has shown great potential to be applied and utilised by industry to deal with post- and pre-combustion of CO2. A systematic review has been conducted to analyse and assess CO2 removal using membrane contactors for capturing techniques in industrial processes. The review began with a total of 2650 papers, which were obtained from three major databases, and then were excluded down to a final number of 525 papers following a defined set of criteria. The results showed that hollow fibre membranes have demonstrated popularity, as well as the use of amine solvents for CO2 removal. This current systematic review in CO2 removal and capture is an important milestone in the acknowledgment of up to date research with the potential to serve as a benchmark databank for further research in similar areas of work. This study provides the first systematic enquiry in the evidence to research further sustainable methods to capture and separate CO2

Recent progress on sonochemical production for the synthesis of efficient photocatalysts and the impact of reactor design

Sonochemical-assisted synthesis has flourished recently for the design of photocatalysts. The main power used is ultrasound that allows the nanomaterials shape and size modification and control. This review highlights the effect in formation mechanism by ultrasound application and the most common photocatalysts that were prepared via sonochemical techniques. Moreover, the challenge for the suitable reactor design for the synthesis of materials or for their photocatalytic evaluation is discussed since the most prominent reactor systems, batch, and continuous flow, has both advantages and drawbacks. This work summarises the significance of sonochemical synthesis for photocatalytic materials as a green technology that needs to be further investigated for the preparation of new materials and the scale up of developed reactor systems to meet industrial needs

Experimental and process modelling investigation of the hydrogen generation from formic acid decomposition using a pd/zn catalyst

The use of hydrogen as a renewable fuel has attracted great attention in recent years. The decomposition of formic acid under mild conditions was investigated using a 2%Pd6Zn4 catalyst in a batch reactor. The results showed that the conversion of formic acid increases with reaction temperature and with the formic acid concentration. A process-simulation model was developed to predict the decomposition of formic acid using 2%Pd6Zn4 in a batch reactor. The model demonstrated very good validation with the experimental work. Further comparisons between the 2%Pd6Zn4 catalyst and a commercial Pd/C catalyst were carried out. It was found that the 2%Pd6Zn4 demonstrated significantly higher conversions when compared with the commercial catalyst

Gastric Marginal Zone B Cell Lymphoma of the Duodenum

Small bowel lymphomas of the extranodal type occur in the young and are characteristically associated with malabsorption syndrome. We present the case of an elderly in whom there was no malabsorption and the duodenal tumor was a gastric type marginal zone B cell lymphoma also known as gastric mucosa-associated lymphoid tissue (MALT) lymphoma. A 73-year-old woman presented to the emergency room with 2 weeks of general weakness, recurrent vomiting containing food particles and abdominal distension. She had been diagnosed with diabetic gastroparesis 4 years prior. CT of the abdomen and pelvis was suggestive of gastric outlet obstruction but no evidence of pancreatic or duodenal mass. Endoscopy and biopsy of the tumor obstructing the distal first part of the duodenum confirmed a gastric marginal MALT lymphoma. The patient's symptoms improved with radiotherapy. Gastric MALT lymphoma, an extranodal lymphoma primarily described in the stomach, can also present in the small bowel and is not associated with malabsorption

Management of primary hepatic malignancies during the COVID-19 pandemic: recommendations for risk mitigation from a multidisciplinary perspective

Around the world, recommendations for cancer treatment are being adapted in real time in response to the pandemic of COVID-19. We, as a multidisciplinary team, reviewed the standard management options, according to the Barcelona Clinic Liver Cancer classification system, for hepatocellular carcinoma. We propose treatment recommendations related to COVID-19 for the different stages of hepatocellular carcinoma (ie, 0, A, B, and C), specifically in relation to surgery, locoregional therapies, and systemic therapy. We suggest potential strategies to modify risk during the pandemic and aid multidisciplinary treatment decision making. We also review the multidisciplinary management of intrahepatic cholangiocarcinoma as a potentially curable and incurable diagnosis in the setting of COVID-19

Genotoxicity assessment of amino zinc nanoparticles in wheat (Triticum aestivum L.) as cytogenetical perspective

This is the final version. Available on open access from Elsevier via the DOI in this record. Nanoparticles have a positive impact in several subjects especially in agriculture, while their safety is still being debated. Numerous commercial nano pesticide, insecticides, and fertilizers products are found in the local markets without any intensely studies on the side effect of these products on plant, human as well as environmental effects. The present study aimed to evaluate the genotoxicity of commercial amino zinc nanoparticles (AZ NPs) on Triticum aestivum L. during seeds germination and root elongation using concentration ranges (50, 100, and 150 ppm) at different exposure times (8, 16 and 24 hrs). Long term exposure to AZ NPs, exhibited only slight variation in germination rates and the elongation of roots was affected by AZ NPs treatment ranged from 97.66 to 100%. Significant reduction in the mitotic index was 35.33% after 24 hrs and 150 ppm of AZ NPs, was also observed comparing with control which was 88.0%. Genotoxicity was evaluated at a cytological level in root meristems that revealed sever variations in mitotic activity, chromosomal aberrations, and micronuclei release. Results exhibited that nano amino zinc could enter effortlessly into the cells and inhibit the normal cellular function. The decrease in the emergence of chromosomal aberrations resulting from AZ NPs exposure in a dose-dependent manner was clearly indicated that AZ NPs has induced genotoxic effect on wheat root tips.King Saud University, Riyadh, Saudi Arabi

A study to assess changes in myocardial perfusion after treatment with spinal cord stimulation and percutaneous myocardial laser revascularisation; data from a randomised trial

<p>Abstract</p> <p>Background</p> <p>Spinal cord stimulation (SCS) and percutaneous myocardial laser revascularisation (PMR) are treatment modalities used to treat refractory angina pectoris, with the major aim of such treatment being the relief of disabling symptoms. This study compared the change in myocardial perfusion following SCS and PMR treatment.</p> <p>Methods</p> <p>Subjects with Canadian Cardiovascular Society class 3/4 angina and reversible perfusion defects as assessed by single-photon emission computed tomographic myocardial perfusion scintigraphy were randomised to SCS (34) or PMR (34). 28 subjects in each group underwent repeat myocardial perfusion imaging 12 months post intervention. Visual scoring of perfusion images was performed using a 20-segment model and a scale of 0 to 4.</p> <p>Results</p> <p>The mean (standard deviation) baseline summed rest score (SRS) and stress scores (SSS) were 4.6 (5.7) and 13.6 (9.0) in the PMR group and 6.1 (7.4) and 16.8 (11.6) in the SCS group. At 12 months, SRS was 5.5 (6.0) and SSS 15.3 (11.3) in the PMR group and 6.9 (8.2) and 15.1 (10.9) in the SCS group. There was no significant difference between the two treatment groups adjusted for baseline (p = 1.0 for SRS, p = 0.29 for SSS).</p> <p>Conclusion</p> <p>There was no significant difference in myocardial perfusion one year post treatment with SCS or PMR.</p