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Transportation of waxy crude oil in a production pipeline often encountered flow assurance issues, such as wax deposition. In a case where pipeline shutdown is needed, wax deposit is likely to form within the pipelines, which leads to operational complexity during the restart phase. Commonly, crude oil restarts to flow after a significantly high restart pressure is pumped longer than is necessary. This is due to the physical hindrance caused by the solid wax, which requires additional pressure to disintegrate it before achieving a steady crude oil flow. This study aims to investigate the effect of crude oil and nitrogen gas flow rates on the time taken for crude oil flow initiation using a flow loop rig, which is connected to a nitrogen gas injection system. The nitrogen gas was injected into the test section pipeline at predetermined flow rates within specified periods. After 45 min of static cooling, the crude oil gear pump is switched on to build sufficient pressure to initiate the waxy crude oil flow in the pipeline. Additionally, a statistical analysis by the response surface methodology was also performed by Minitab® 19 software. Results show that the maximum reduction in flow initiation is 73.7% at 5 L/min of crude oil and 1 L/min of nitrogen gas. This study reveals that the presence of nitrogen gas improved the pipeline restart phase by minimizing both restart pressure and time taken for flow initiation.

Considering the value of coconut shell biomass as renewable fuels in homes and commercial industries, its effectiveness as a biomass resource has been overlooked by our rural citizens and researchers. Carbonization experiments of coconut shell biomass were conducted in a downdraft carbonization reactor (750 mm height and 67 mm diameter) to determine the effect of temperature (250 to 600 °C, in 50 °C intervals) on the charcoal properties. This was to address the problems of traditional charcoal production methods that include; low yield, environmental pollution, unregulated temperature, and poor quality properties. Yet the scarcity of this information hampers efforts for efficient commercial production. The coconut shell biomass was obtained from a local shop in Malaysia. It was heated in the reactor at a fixed residence time of 60 min and a particle size of 5 mm with nitrogen as a carrier gas. The relationship between temperature and the properties of coconut shell charcoal has been ascertained by the findings of this analysis. The relatively high the temperature, the better the charcoal quality, but the lowest the charcoal yields, since the secondary pyrolysis reaction expends charcoal. It was noted that, up to a final temperature of 500 °C, the yield reduction was rapid; after that, it was slower at 550 °C and almost stable at 600 °C. According to the charcoal’s proximate analysis, the calorific value, fixed carbon content, carbon content and ash content increased with temperature. Whereas, the charcoal density, volatile matter, moisture content, and conversion efficiencies decrease with temperature. The presence of nitrogen gas appears to have reduced combustion reactions that promote the formation of carbon dioxide (CO2). The methods produce the least amount of air pollutants (96 g carbon monoxide (CO), 167 g CO2, and 64 g methane (CH4) per 1 kg of charcoal production). The type of biomass and carbonization kiln has an impact on the production of CO, CO2, and CH4. Thus, the carbonization reactor used in this study has the potentials to produce an eco-friendly charcoal with superior quality properties that can assist in reducing environmental pollution, by proper selections of carbonization temperature.

Syngas production from biomass gasification is a potentially sustainable and alternative means of conventional fuels. The current challenges for biomass gasification process are biomass storage and tar contamination in syngas. Co-gasification of two biomass and use of mineral catalysts as tar reformer in downdraft gasifier is addressed the issues. The optimized and parametric study of key parameters such as temperature, biomass blending ratio, and catalyst loading were made using Response Surface Methodology (RSM) and Artificial Neural Network (ANN) on tar reduction and syngas. The maximum H2 was produced when Portland cement used as catalyst at optimum conditions, temperature of 900 °C, catalyst-loading of 30%, and biomass blending-ratio of W52:OPF48. Higher CO was yielded from dolomite catalyst and lowest tar content obtained from limestone catalyst. Both RSM and ANN are satisfactory to validate and predict the response for each type of catalytic co-gasification of two biomass for clean syngas production.

The erosion failure of oil transmission lines is mainly caused by the migration of quartz, sand, silt and clay into the processing units. Apart from the solid particles, the fluid viscosity also impacts the erosion-related failure of the processing units. The role of sand carrier viscosity in wear damage to pipelines, however, is not well understood. In this study, the wear performance of carbon steel coupons in polymer-sand-water slurry was investigated by varying the slurry viscosity from 1 to 19 cP. The water-soluble polyvinyl alcohol was used to modify the viscosity of the carrier fluid. At a fluid velocity of 6 m/s, the Reynolds number decreased from 165,000 to 8684 with a rise in viscosity from 1 to 19 cP. Similarly, at 10 m/s, the Reynolds number decreased from 330,000 to 17,368 for a similar change in the fluid viscosity. Each coupon was exposed to the fluid stream for 10 hours. Universal scanning probe microscopy (USPM) revealed more rough topology at lower viscosities and relatively smoother topology at higher viscosities. The erosion rate decreased from 6.31 ± 0.41 to 1.27 ± 0.16 mm/year and microhardness from 102 VHN to 98.2 VHN with a rise in viscosity from 1 to 19 cP. The USPM method revealed slightly higher erosion rates as compared to the weight loss method.

This study investigated the effect of input power and process time on microwave-metal interaction pyrolysis of pure plastics (PS, PP, LDPE) and their blends into liquid and gaseous fuels. The microwave power and time were varied to pyrolyze 20 g of each sample in an iron coil. The pure PS underwent maximum conversion into fuels followed by PP and LDPE. Under optimized microwave power (2100–2500 W), PS produced 88.7% oil after 19 min of reaction time, PP produced 54.65% oil at 23 min of reaction time and LDPE produced 30.15% oil after 26 min of reaction time. Pure PS and PP showed high conversion efficiency of 95.40% and 95.10%, respectively, into liquid and gaseous fuels. Pure LDPE showed only 54.30% conversion into fuels by producing large quantity of waxy residue. In blended form, PS-PP blend revealed highest conversion of 65.67% into fuels followed by PS-PP-LDPE blend (57.23%), PS-LDPE blend (46.52%) and PP-LDPE blend (28.08%). Based on mass balance and percentage conversion, PS-PP blend showed maximum conversion of 96.25% whereas PP-LDPE showed minimum conversion of 74.99%. Higher microwave powers within optimal range produced better yield of liquid fuel in shorter time periods. The pyrolytic oils contained some useful aromatic and aliphatic hydrocarbons (C8–C16).

This study is aimed at testing Mechanical earth modeling (MEM) and Sand onset production prediction (SOP) models using well log and core data to estimate the mechanical properties of the rock, in-situ stresses and the critical conditions at which the rock failure may occur. New numerical models were developed to predict the onset of sand production for Well X. The outputs from MEM were coupled with the Mohr Coulomb failure criterion to calculate the critical wellbore pressure of the well and consequently the depth of the rock at which failure may occur. The results showed that at depth of 1061.68–1098.10 m, the calculated critical wellbore pressures were negatives, which reveal low possibility of sand production. However, at a depth of 1098.25–2230.89 m, the calculated critical wellbore pressures were positives. In this depth range, there was high possibility of rock failure. In conclusion, based on the findings, Well X may produce sand at depth deeper than 1100 m. Therefore, mitigation and preventive actions should be planned for Well X to handle and manage the possible sand production from the identified interval.

This study had compared raw biomass and pre-treated biomass co-gasified with coal with the aim of investigating the reliability of pre-treated biomass for enhancing gasification performance. Sawdust (SD) and wood pellet (palletisation form of sawdust - WP) and blends of these two feedstocks with sub-bituminous coal (CL), were gasified in an air atmosphere using an external heated fixed-bed downdraft gasifier system. Response surface methodology (RSM) incorporating the central composite design (CCD) was applied to assist the comparison of all operating variables. The three independent variables were investigated within a specific range of coal blending ratios from 25% to 75%, gasification temperature from 650 °C to 850 °C and equivalence ratio from 0.20 to 0.30 against the dependent variables, namely the H2/CO ratio and higher heating value of the syngas (HHVsyngas). The results revealed the H2/CO ratio and a higher heating value of the syngas of more than 1.585 and 6.072 MJ/Nm3, respectively. Findings also showed that the H2/CO ratio in the syngas from CL/WP possessed a higher value than the CL/SD. In contrast, CL/SD possessed a higher heating value for syngas with about 1% difference compared to the CL/WP. Therefore, co-gasified coal with wood pellets could potentially be a substitute for sawdust.

Palm kernel shell (PKS) biomass has great potential for power generation via gasification as it contains high energy content. However, abundant it may be, the source of PKS is scattered throughout the country, thus the consistency of feedstock supply may be hard to maintain. Co-gasifying with another source, such as plastics, can be seen as one of a solution to mitigate the supply chain problem. Polystyrene (PS) plastics have potential as a plastic feedstock because of its high domestic and industrial usage. As PS is also hard to recycle, using PS as a co feedstock for gasification is a way for PS waste management. However, the study on the performance of air co-gasification of PKS and PS has not been done before. It is essential to investigate the performance before it is utilized in the real world. In this work, the performance co-gasification of PKS and PS with different operating conditions was investigated. The gasification experiment was done in an electrically heated downdraft gasifier with a diameter of 8 cm. The reaction temperature was varied from 700 to 900 °C, with the equivalence ratio varied from 0.07 to 0.27. The PS weight percentage of the total feedstock was varied from 0 to 30 wt%. It was found that the vol% of CO and H2 on the producer gas increased with temperature while reducing the vol% of CO2 and CH4. HHV and the amount of gas produced were also increasing with increasing temperature. Increasing ER reduced the HHV of the gas but increased the amount of gas produced. Adding more PS to the feedstock blend increased the percentage of the produced gas at 900 °C, however, at the lower temperature of 800 °C, the percentage of gas produced decreased with increasing PS wt%.

In this work, a comparative analysis of the gasification process of sawdust (SW) and sawdust pellet (SWP) utilizing a downdraft gasifier was performed. The gasification was conducted in a research-scale fixed-bed gasifier applying air as an oxidizing agent. The comparison between the raw (sawdust, SW) and treated biomass (sawdust pellet, SWP) was investigated for the syngas composition and gasification performance at the fixed condition of gasification temperature at 750 °C and equivalence ratio of 0.25. The gasification performance was tabulated in the form of heating value of the syngas (HHVsyngas), gasification efficiency (ηGE) and carbon conversion efficiency (ηCCE). It was found out that SWP produced the highest H2 and the lowest CO2. Furthermore, SWP also present the better gasification performance than SW. SWP achieved the high HHVsyngas, ηGE, and ηCCE at 4.2152 MJ/Nm3, 24% and 37%, respectively.

The world does not have too much time to ensure that the fast-growing population has enough land, food, water and energy. The rising food demand has brought a positive surge in fertilizers’ demand and agriculture-based economy. The world is using 170 million tons of fertilizer every year for food, fuel, fiber, and feed. The nitrogenous fertilizers are being used to meet 48% of the total food demand of the world. High fertilizer inputs augment the reactive nitrogen levels in soil, air, and water. The unassimilated reactive nitrogen changes into a pollutant and harms the natural resources. The use of controlled-release fertilizers for slowing down the nutrients’ leaching has recently been practiced by farmers. However, to date, monitoring of the complete discharge time and discharge rate of controlled released fertilizers is not completely understood by the researchers. In this work, corn starch was thermally processed into a week gel-like coating material by reacting with urea and borate. The granular urea was coated with native and processed starch in a fluidized bed reactor having bottom-up fluid delivery system. The processed starch exhibited better thermal and mechanical stability as compared to the native starch. Unlike the pure starch, the storage modulus of the processed starch dominated the loss modulus. The release time of urea, coated with processed starch, remained remarkably larger than the uncoated urea.

Wind speed forecasts can boost the quality of wind energy generation by increasing the efficiency and enhancing the economic viability of this variable renewable resource. This work proposes a hybrid model for wind energy capacity for electrical power generation at coastal sites by utilizing wind-related variables' characteristics. The datasets of three coastal locations of Kuwait validate the proposed method. The hybrid model is a merger of Artificial Neural Network (ANN) and Particle Swarm Optimization (PSO) and predicts one-month-ahead wind speed for wind power density calculation. The neural network starts its performance evaluation with a variable number of hidden-layer neurons to finally identify the optimal ANN topology. Comparisons of statistical indices with both expected and observed test results indicate that the ANN-PSO based hybrid model with the low root-mean-square-error and mean-square-error values outperforms ANN-based trivial models. The prediction model developed in this work is highly accurate with a Mean Absolute Percentage Error (MAPE) of approximately (3-6%) for all the sites.

The air gasification of palm waste specifically palm kernel shell has been performed in the fixed bed gasifier using coal bottom ash as a potential catalyst. Effect of the process variables (temperature, catalyst loading, and airflow rate) has been investigated on the product gas composition. The design of experiments was accomplished using the Design Expert v11® with a Central Composite Design approach. Moreover, the parametric study and optimization of the entire process have been carried out using Response Surface Methodology within the specific range of variables. The results suggested that the temperature has been found as the most influencing parameter for increment of H2 and CO production. Whereas, airflow rate was more sensitive for CH4 and CO2 production. Catalyst loading was found very effective for the amplified amount of H2 and CO production and the reduction in the amounts of CO2 and CH4, caused by the catalytic activity of coal bottom ash (CBA). Optimized parameters are found to be the temperature of 850 °C, catalyst loading of 14.50 wt%, and airflow rate of 2.50 L/min, which predicted the composition for H2 of 31.38 vol%, CO of 26.44 vol%, CH4 of 15.67 vol%, and CO2 of 25.59 vol%.

Production of waxy crude oil from offshore fields has increased in the last decade. However, the operation is being challenged with the high wax content of crude oil that tends to precipitate at lower temperature. This paper presents the effects of hydrostatic pressure on the voids formed in waxy crude oil gel. A flow loop rig that simulates offshore waxy crude oil transportation was used to produce the gel. A Magnetic Resonance Imaging of 3-Tesla system was used to scan the gelled samples in horizontal and vertical pipes. The hydrostatic pressure effect was found to be most significant near the pipe wall as a change in percent voids volume of 0.53% was observed at that region. In particular, the voids volume reduction was more pronounced in the lower half side of the pipe. The total volume of voids in the vertical pipe was lower than that in the horizontal pipe, and this suggests that the gel in the vertical pipe became denser due to the effects from the hydrostatic pressure. Conversely, the voids volume around the pipe core in the vertical pipe was higher when compared to that in the horizontal pipe. The change in voids volume near the pipe core and wall shrunk to a minimum and converged to 0.18% voids volume at larger duration of the hydrostatic effect. Further, hydrostatic pressure was observed to have significant influences for higher duration making the void size to be distributed across and along the pipeline; however, it was found to have insignificant effects on voids size distribution for smaller duration. The findings of this study can help for better understanding of voids formation in vertical pipelines that would further assist in developing a model predicting restart pressure accurately.

In the present study, a stoichiometric thermodynamic equilibrium model has been introduced for downdraft biomass air gasifiers. Experimental data from five pilot scale downdraft gasifiers, that use different types of biomass fuels, are compared with the findings of the model. It is presented that the developed model is efficiently simulating H2, CO, CH4, and CO2, volume fractions and the heating value of synthesis gas. The minimum error of comparisons has been found about 1% and the maximum error was obtained to be less than 25%. The level of sensitivity evaluation has been performed to the model to check out the effect of gasifier temperature, biomass moisture content, air to fuel ratio and equivalence ratio on the syngas form and lower heating value of syngas from the downdraft gasifier. The model results are compared with several existing experimental data of the literature. It is concluded that the findings of the study are a good candidate to model the downdraft gasifiers.

This paper investigates the thermochemical characteristics of date palm fronds (DPFs) to use as feedstock for different energy conversion processes. The proximate analysis, ultimate analysis, calorific value measurements, and elemental content measurements were carried out using some quantitative and qualitative techniques. At later stage, the gasification of DPFs was carried out in an externally hot gasifier system. The effect of gasification temperature and biomass particle size on gas composition and heating value of producer gas was investigated. The results showed that the thermochemical characteristics of DPFs were comparable with other biomass materials reported in the past literature. The gasification trials of the biomass revealed that temperature has a significant effect on gas composition, especially H2 and CO contents. The high temperature yielded high H2 and CO concentrations in the product gas. A good quality gas composition (in terms of H2, CO, CH4, and CO2 contents) was obtained from bigger particle sizes as compared to smaller sizes. The thermochemical characteristics of DPFs and gasification results showed that DPF feedstock is comparable with other conventional biomass for production of energy through appropriate thermochemical technologies.

The formation of voids is eminent below the pour point temperature of waxy crude oil. This paper discusses the temporal variation of voids in waxy crude oil gel in the presence of temperature gradi...

High fertilizer inputs augment the reactive nitrogen level in soil, air, and water. Unused reactive nitrogen acts as a pollutant and harms natural resources. This study focused on the thermal processing of corn starch into a coating material using disodium tetraborate and urea. The processed corn starch was coated over granular urea in a vertical bed coating reactor. The chemically modified starch, when compared with native starch, exhibited better stability and mechanical strength over time. The modified starch looked like a weak gel, and its loss modulus was dominated by the storage modulus. However, for native starch, the viscous component dominated the elastic component, especially at lower angular frequencies. The nitrogen release from the coated urea was remarkably slower than the uncoated one. A small difference in the peak and final starch viscosities in the presence of urea and borate revealed low thermal cracking of the starch molecules. The surface of the granular urea that was coated with chemically modified corn starch was uniform, dense, hard, and least porous. The uncoated urea granules became released into water in 6 min under gentle shaking, whereas the coated urea took almost 32 min to completely release.

In this study, Response Surface Methodology (RSM) in combination with Box-Behnken Design (BBD) was used to optimize the temperature, catalyst loading, and blending ratio for a co-gasification process. The catalytic co-gasification of coconut shells (CS) and oil palm fronds (OPF) blends was performed in the presence of cement, dolomite, and limestone catalysts. A combined effect of temperature, catalyst loading, and blending ratio on production of H2, CO, and tar formation was investigated by using a BBD approach. The results showed the strongest influence of the process temperature on H2 and CO yield, and tar formation followed by the catalyst loading and blending ratio. A catalyst loading of 30 wt%, process temperature of 900 °C and blending ratio of CS50:OPF50 were predicted as the optimized conditions for the reported co-gasification results. The highest H2 yield of 20.64 vol% was produced during catalytic co-gasification of the blended biomass with limestone followed by the cement (18.22 vol%) and dolomite (14.99 vol%). Under optimized process conditions, lowest tar concentration of 0.87 g/Nm3 was obtained with limestone follow by the cement (1.42 g/Nm3) and dolomite (2.13 g/Nm3). However, blending ratio did not affect H2, CO yield, and tar formation appreciably. Conclusively, the mixing ratio of CS and OPF would have a negligible role in controlling the process output.

Gasification is a well proven thermal conversion technology that has been used to convert solid fuel into gaseous fuel. There are different types of conventional feedstocks such as coal and biomass that have been gasified in either individual or blended form. The advantage of co-gasification over typical gasification is the ability to obtain the desired product gas composition by varying the blending ratio and feedstock. Furthermore, it is applicable for many feedstocks such as sewage sludge, black liquor, glycerol, and municipal solid waste. These feedstocks have good thermophysical properties, however, gasification of these feedstocks is difficult using a conventional technique, thus highlighting the need for co-gasification. Recently, the effect of feedstock type and their blending for syngas production have attracted interest among researchers especially when feedstocks are non-conventional. Several review articles have been published on gasification of individual coal and biomass. However, no review that exhaustively dealt with the catalytic co-gasification of a different kind of conventional and non-conventional feedstock. The feedstock type and blending ratio of feedstock are the most important parameters that affect the co-gasification process. The objective of the current paper is therefore to review the effect of feedstock type and their blending ratio on syngas quality, co-gasification performance, and tar formation for catalytic co-gasification of both conventional and non-conventional feedstocks. This review highlights the need for research and development in co-gasification and also provides the research gap for further research to develop a state of art technologies.

Gasification of coconut shell (CS) and palm kernel shell (PKS) is conducted in a batch type downdraft fixed-bed reactor to evaluate the effect of particle size (1–3 mm, 4–7 mm, and 8–11 mm) and temperature (700, 800, and 900 °C) on gas composition and gasification performance. The response surface methodology integrated variance-optimal design is used to identify the optimum condition for gasification. Gas composition, which is measured using the biomass particle size of 1–11 mm at 700–900 °C, are 8.20–14.6 vol% (H2), 13.0–17.4 vol% (CO), 14.7–16.7 vol% (CO2), and 2.82–4.23 vol% (CH4) for CS and 7.01–13.3 vol% (H2), 13.3–17.8 vol% (CO), 14.9–17.1 vol% (CO2), and 2.39–3.90 vol% (CH4) for PKS. At similar conditions, the syngas higher heating value, dry gas yield, carbon conversion efficiency, and cold gas efficiency are 4.01–5.39 MJ/Nm3, 1.50–1.95 Nm3/kg, 52.2–75.9%, and 30.9–56.4% for CS, respectively, and 3.82–5.09 MJ/Nm3, 1.48–1.92 Nm3/kg, 59.0–81.5%, and 33.0–57.1% for PKS, respectively. Results reveal that temperature has a greater role than particle size in influencing the gasification reaction rate.

In the presented work, waste glass was converted into highly porous material through a thermo-chemical reaction. In this conversion, lime was used as flux, salt as a medium and soda as a reactant. The effect of relative concentration of fluxes and reactants on the physicochemical properties of the resulting material were investigated at different temperatures. The porous material product was investigated for its textural and chemical nature using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier Transform infrared spectroscopy (FT-IR) and X ray florescence spectroscopy. SEM analysis showed that the adsorbent had mesoporous and microporous nature. Since porous glass of well-defined pore size and porosity level was fabricated through a hetero-coagulation template processing, the strategy can be developed into a general pathway to prepare various porous inorganic materials with well-defined pore structure. The porous product was also used as an adsorbent for the removal of direct blue dye from aqueous medium. The glass adsorbent significantly removed the Direct blue dye from the aqueous medium. It was observed that the adsorbent can remove 1.27 mg/g of dye after 25 min of treatment.

The main challenge on the fueling of pure hydrogen in the automotive vehicles is the limitation in the hydrogen separation from the product of steam reforming and gasification plants and the storage issues. On the other hand, hydrogen fueling in automotive engines has resulted in uncontrolled combustion. These are some of the factors which motivated for the fueling of raw syngas instead of further chemical or physical processes. However, fueling of syngas alone in the combustion chamber has resulted in decreased power output and increased in brake specific fuel consumption. Methane augmented hydrogen rich syngas was investigated experimentally to observe the behavior of the combustion with the variation of the fuel-air mixture and engine speed of a direct-injection spark-ignition (DI SI) engine. The molar ratio of the high hydrogen syngas is 50% H2 and 50% CO composition. The amount of methane used for augmentation was 20% (V/V). The compression ratio of 14:1 gas engine operating at full throttle position (the throttle is fully opened) with the start of the injection selected to simulate the partial DI (180° before top dead center (BTDC)). The relative air-fuel ratio (λ) was set at lean mixture condition and the engine speed ranging from 1500 to 2400 revolutions per minute (rpm) with an interval of 300 rpm. The result indicated that coefficient of variation of the indicate mean effective pressure (COV of IMEP) was observed to increase with an increase with λ in all speeds. The durations of the flame development and rapid burning stages of the combustion has increased with an increase in λ. Besides, all the combustion durations are shown to be more sensitive to λ at the lowest speed as compared to the two engine speeds.

This study deals with valorization of the protein-rich fish and poultry waste. Since fish scales and chicken feathers are hard-to-degrade by the scavenger microbes, they were hydrolyzed into a source material for construction of rechargeable protein batteries. Both wastes were dissolved in sodium hydroxide (NaOH) solution to form oxidizing and reducing halves of the battery. NaOH not only worked as a hydrolyzing agent but electrolyte for battery as well. Different parameters including NaOH concentration, salt bridge, charge storage capacity, charging time and quantity of the waste were optimized to get maximum output from the protein battery. The optimum concentration of NaOH was measured about 0.75 M. The waved-thread wick was found the best salt bridge and maximum charger power was obtained at 24 V with 10 min of charging time. The scale to feather ratio of 4:5 was found best condition for construction of protein battery with stable output. The constructed battery was found effective in both open and closed circuits. Light emitting diodes were used as a load for the closed circuit.