Abdul Waheed Bhutto

Hydrothermal carbonization of oil palm shell

Palm shell is one of the most plentiful wastes of the palm oil mill industry. This study identifies the capability of hydrothermal carbonization process (HTC) to convert palm shell into high energy hydrochar. The influence of reaction time and reaction temperature of the HTC process was investigated. The process parameters selected were temperature 200 °C to 240 °C, time 10 to 60min, and water to biomass ratio was fixed at 10 : 1 by weight %. Fourier transform infrared (FTIR), elemental, proximate, Burner Emmett and Teller (BET), thermo-gravimetric (TGA) analyses were performed to characterize the product and the feed. The heating value (HHV) was increased from 12.24 MJ/ kg (raw palm shell) to 22.11 MJ/kg (hydrochar produced at 240 °C and 60 min). The hydrochar yield exhibited a higher degree inverse proportionality with temperature and reaction time. Elemental analysis revealed an increase in carbon percentage and a proportional decrease in hydrogen and oxygen contents which caused higher value of HHV. The dehydration and decarboxylation reactions take place at higher temperatures during HTC resulting in the increase of carbon and decrease in oxygen values of hydrochar. The FESEM results reveal that the structure of raw palm shell was decomposed by HTC process. The pores on the surface of hydrochar increased as compared to the raw palm shell.

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.

Strategies for the consolidation of biologically mediated events in the conversion of pre-treated lignocellulose into ethanol

Notwithstanding the plentiful published work on the production of ethanol from lignocellulosic materials this comprehensive review relates how the basic research of a commercially viable industrial production strategy is still lacking. The objective of this review is to compile information on the different strategies and to consolidate the biologically mediated events involved in the conversion of pre-treated lignocellulose to ethanol and associated expenses so that some generalized information can be developed that could help policy makers and other stakeholders in designing a policy framework to promote second generation biofuels. The review also discusses the potential of process integration, its cost competitiveness and role in establishing commercial facilities for the production of ethanol from lignocellulosic biomass.

Coal gasification for sustainable development of the energy sector in Pakistan

Pakistan has 19.5 gigawatts (GW) of electric generating capacity. The total power generating capacity has increased rapidly in recent years, due largely to foreign investment, leading to a partial alleviation of the power shortages Pakistan often faces in peak seasons. Rotating blackouts are, however, still necessary in some areas. The rules of the game for generating electricity are changing rapidly. The countrys remaining recoverable reserves of crude oil are estimated at 42.28 million tonnes (Mt) (310 million barrels; 1 barrel = 0.1364 t). Thus, there is no prospect for Pakistan to reach self-sufficiency in oil. Pakistan has 853.19 billion cubic metres (Gm 3 ) of proven gas reserves, and currently produces around 104.23 million m 3 (Mm 3 ) per day. While the energy demand is surging in Pakistan, at the same time pressure is building worldwide to reduce greenhouse gas emissions. Pakistan is looking forward to finding ways to overcome the disadvantages of coal resulting from its relatively higher moisture, sulfur and ash content, in order to use this readily-available, indigenous resource to generate clean, reasonably-priced electricity. One way to overcome this problem is to convert coal from a solid to a clean gaseous fuel, which can then be burned like natural gas. When linked with modern combined-cycle turbines, gasification is one of the most efficient and environmentally sound ways of producing electricity from coal. Coal IGCC (integrated gasifier combined-cycle) power plants offer numerous benefits for the environment, power producers and consumers. This technology can help diversify the fuel supply and help balance Pakistans future dependence on foreign sources of energy.

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.

Parametric study of pyrolysis and steam gasification of rice straw in presence of K2CO3

A parametric study of pyrolysis and steam gasification of rice straw (RS) was performed to investigate the effect of the presence of K2CO3 on the behavior of gas evolution, gas component distribution, pyrolysis/gasification reactivity, the quality and volume of synthetic gas. During pyrolysis, with the increase in K2CO3 content in RS (i) the instantaneous CO2 concentration was increased while CO concentration was relatively stable; (ii) the yield of CO2 and H2 increased on the cost of CH4. During steam gasification of RS, with the increase in K2CO3 content in RS (i) the instantaneous concentration of CO2 and H2 increased while instantaneous concentration of CO and CH4 decreased; (ii) the yield of CO2 and H2 production and total yield increased; and (iii) yield of CO and CH4 production followed the order: 9% K2CO3 RS<6% K2CO3 RS<raw RS<3% K2CO3 RS<water-leached RS. Water-leached RS showed the highest pyrolysis reactivity, while stream gasification reactivity was proportional to K2CO3 content in RS. The results of this study reveal that the presence of K2CO3 during pyrolysis and steam gasification of RS effectively improves production of H2 rich gas.

N-methyl-2-pyrrolidonium-based Brönsted-Lewis acidic ionic liquids as catalysts for the hydrolysis of cellulose

We experimentally studied the catalytic performances of a series of Brönsted-Lewis acidic N-methyl-2-pyrrolidonium metal chlorides ([Hnmp]Cl/MClx, where M=Fe, Zn, Al, or Cu) for the hydrolysis of microcrystalline cellulose (MCC) and cotton to produce reducing sugar. A variety of factors, such as temperature, time, ionic liquid (IL) species, IL dosage, and the concentration of the metal chloride were investigated. [Hnmp]Cl/FeCl3 presented the best hydrolysis performance, affording a 98.8% yield of total reducing sugar from MCC (1 h, 100 °C, 0.1 g MCC, 0.2 g acidic IL, 2.0 g [Bmim]Cl as solvent), which is better than or comparable to results previously obtained with other–SO3H functionalized acidic ILs. The hydrolysis performances of [Hnmp]Cl/MClx were rationalized using density functional theory calculations, which indicated that interactions between the metal chlorides and the cellulose, including charge-transfer interactions are important in the hydrolysis of cellulose and degradation of glucose. This work shows that Brönsted-Lewis acidic ILs are potential catalysts for the hydrolysis of cellulose to produce sugar.

Synthesis of magnetic carbon nanocomposites by hydrothermal carbonization and pyrolysis

The fabrication of magnetic carbon nanostructures is emerging to develop composites with unique properties. Consolidating magnetic nanoparticles with carbon materials can be used in nanoelectronics, catalysis, optical application, biosensors, environmental remediation, energy, hydrogen storage, drug transport, magnetic resonance imaging and cancer diagnosis. In addition, thermochemical methods such as hydrothermal carbonization and pyrolysis are low energy processes that offer an efficient synthesis of the controlled morphology of magnetic carbon nanocomposite. These methods provide chemical and morphological improvements of the structure, such as high surface area, ordered nanosizes, crystal matrix, material stability, electrical conductivity, magnetic saturation and coercivity. This paper reviews the fabrication and properties of magnetic carbon nanocomposites.

An overview of microwave hydrothermal carbonization and microwave pyrolysis of biomass

Biomass utilization has received much attention for production of high density solid fuels. Utilization of cheap and naturally available precursors through environmentally friendly and effective processes is an attractive and emerging research area. Pyrolysis and hydrothermal carbonization (HTC) are well-known technologies available for production of solid biofuel using conventional or microwave heating. Microwave heating is a simpler and more efficient heating method than conventional heating. This study presents a critical review on microwave pyrolysis and microwave HTC for solid fuel production in terms of yield and quality of products. Moreover, a brief summary of parameters of microwave pyrolysis and microwave HTC are discussed. The fuel, chemical, structural and thermal weight loss characteristics of solid fuels produced from different biomass are discussed and compared.