Rashid Abro

A review of extractive desulfurization of fuel oils using ionic liquids

Hydrodesulfurization (HDS), a widely employed method in industries for the desulfurization of fuel oils, such as gasoline and diesel fuel is faced with the challenge of producing lower-sulfur or sulfur-free fuel oils, which are required by more and more countries. However, HDS is not very effective for the removal of thiophenic sulfur compounds due to sterically-hindered adsorption on the catalyst surface, unless operated under harsh conditions, such as high temperature, high pressure, and requirement of a noble catalyst and hydrogen. Extractive desulfurization (EDS) of fuel oils using ionic liquids (ILs) has been intensively studied in recent decades and has a good future as an alternative or complementary method to HDS. In this review, we reviewed the research results of EDS using ILs and provided comprehensive discussions on diverse factors, which influence desulfurization, such as the IL species, IL–oil mass ratio, initial sulfur content, temperature, time, mutual solubility, multiple extractions and regeneration. Potential problems or shortcomings were also stated. Some other desulfurization methods currently under study, such as extraction, oxidation, adsorption and biodesulfurization were also briefly outlined. It can be inferred that ILs remain a class of ideal solvents to realize clean fuel oil in the near future because of their desirable physiochemical properties, which are lacking in molecular organic solvents, while there are possible challenges, such as relatively high viscosity and low efficiency.

Progress in the production of biomass-to-liquid biofuels to decarbonize the transport sector – prospects and challenges

Annually the transport sector consumes a quarter of global primary energy and is responsible for related greenhouse gas emissions. Presently, petroleum derived liquid fuels are the overwhelming source of energy for the transport sector. Liquid biofuels are a viable substitution for petroleum-derived fuels in the transport sector and an important option to mitigate greenhouse gas emissions, especially CO2 emissions. Substituting petroleum-derived fuels with liquid biofuel is also anticipated to reduce the dependency of the transport sector on fossil fuels. Different options are available for the production liquid biofuels. However, the production of liquid biofuels from lignocellulosic biomass has certain advantages. These advantages include the high abundance, availability, low procurement cost and current under-utilization of lignocellulosic biomass. However, the potential for successful deployment of technologies to produce liquid biofuel from lignocellulosic biomass and their cost reductions are surrounded by large uncertainties. High cost of production of liquid fuels from lignocellulosic biomass and their commercial immaturity are major obstacles for the widespread application of liquid biofuels in transportation. Other obstacles include the lack of infrastructure and lack of political as well as public support. This article reviews the obstacles behind the limited production of biomass to liquid (BTL) fuels and their diffusion in the transport sector. The potential approaches to make the production of lignocellulosic-based liquid biofuels economically attractive are also discussed. An approach that focuses on integrating individual operations and processes and adequately modelling these processes evaluated on the bases of the entire pathway can help in realizing the large scale commercial production of liquid biofuels through cleaner production.

Carbon Material Optimized Biocathode for Improving Microbial Fuel Cell Performance.

To improve the performance of microbial fuel cells (MFCs), the biocathode electrode material of double-chamber was optimized. Alongside the basic carbon fiber brush, three carbon materials namely graphite granules, activated carbon granules (ACG) and activated carbon powder, were added to the cathode-chambers to improve power generation. The result shows that the addition of carbon materials increased the amount of available electroactive microbes on the electrode surface and thus promote oxygen reduction rate, which improved the generation performance of the MFCs. The Output current (external resistance = 1000 Ω) greatly increased after addition of the three carbon materials and maximum power densities in current stable phase increased by 47.4, 166.1, and 33.5%, respectively. Additionally, coulombic efficiencies of the MFC increased by 16.3, 64.3, and 20.1%, respectively. These results show that MFC when optimized with ACG show better power generation, higher chemical oxygen demands removal rate and coulombic efficiency.

Extractive denitrogenation of fuel oils using ionic liquids: a review

Elimination of nitrogen (N) compounds contained in fuel oils is one of the essential processes for petroleum refinery due of their hindering consequences on the hydrodesulfurization (HDS) process. Traditional hydrodenitrogenation (HDN) techniques have some barriers to produce lower-N or N-free fuel oils, e.g., HDN is less effective to remove some cyclic N-compounds; HDN is expensive because of operating conditions such as high pressure and high temperature, and also requires the presence of an expensive catalyst and hydrogen. Application of ionic liquids (ILs) for the purpose of fuel oil extractive denitrogenation (EDN) has been an important part of research in recent years, and it has shown huge potential as an effective substitute or supplemental technique to HDN. In the present review, we studied research results of EDN using ILs and have discussed widely the diversified factors influencing denitrogenation. This review concludes that EDN employing ILs has a promising future owing to the ideal physical and chemical characteristics of ILs; though for such a new technology there are some challenges, for which a discussion is also given. This review contributes proposals for possible commercial application of ILs in EDN.

A Comparative Study of Recycling of Used Engine Oil Using Extraction by Composite Solvent, Single Solvent, and Acid Treatment Methods

Engine oils are made from crude oil and its derivatives by mixing of certain other chemicals (additives) for improving their certain properties. Lubricating oil is used to lubricate moving parts of engine, reducing friction, protecting against wear, and removing contaminants from the engine, act as a cleaning agent, and act as an anticorrosion and cooling agent. This research effort focuses on comparative study of re-refined engine oils by extraction of composite solvent, single solvent, and acid treatment methods. Composite solvent was made up of butanol-propane and butanone; propane was used as single solvent. Different properties of refined oil and waste oil were analyzed, such as cloud and pour point, flash point, specific gravity, ash content, viscosity, moisture ratio and acid value. On the basis of experimental work, it was found that the iron contamination decreased from 50 ppm to 13 ppm for composite solvent; for propane solvent it decreased up to 30 ppm and 15 ppm for acid treatment. Results from the flash point, pour point, viscosity, specific gravity, and ash percentage were improved at different degrees, but the best results were seen by using the composite solvent with having drawback of expensiveness.

Oxidative Desulfurization of Gasoline by Ionic Liquids Coupled with Extraction by Organic Solvents

In this work, desulfurization of real fluidized catalytic cracking (FCC) gasoline was investigated in dual steps; first in oxidative desulfurization (ODS) using imidazolium and pyrrolidonium based Bronsted acidic ionic liquids (ILs) as solvent and catalyst and hydrogen peroxide as oxidant. In second step, extractive desulfurization took place using organic solvents of furfural, furfural alcohol and ethylene glycol. Variety of factors such as temperature, time, mass ratio of oil/ILs and regeneration and recycling of ILs, multiple-step desulfurization of ILs and organic solvents and solvent/oil ratio were also investigated. The S-content was significantly decreased to ca. 18 ppm from initial S-content of 260 ppm with a total S-removal of ca. 95% in one-step ODS using pyrrolidonium based ILs coupled with five-step extraction desulfurization (EDS) using furfural alcohol as extractant. This work shows that oxidative desulfurization using ionic liquids coupled with extractive desulfurization using organic solvents is a potential method to produce clean gasoline.

Practical Application of Solar Energy at Desert of Tharparkar, Pakistan

Tharparkar is a backward district of Sindh, Pakistan. Most of the rural population of this district suffers from poverty and is deprived of very basic necessities of life such as drinking water and electricity. Demographic pattern was the main hurdle for rural electrification as the villages are scattered far apart in a random manner and a grid supplied electrical distribution was not technically feasible. Solar energy is one of the alternatives for rural electrification and other applications at desert of Tharparkar. This chapter presents the practical applications of solar energy at desert of Tharparkar, Pakistan. Alternative Energy Development Board (AEDB) has successfully electrified 50 villages of Tharparkar district through about 168 kW of DC power. A solar refrigerator has also been installed at BHU of village Khensir taluka Chacharo to store vaccines for snake bites and other lifesaving drugs. Remarkable socioeconomic and sociocultural change has been visualized in the dark areas which has been brightened through solar energy.