The Study of Optimization of Flocculation and Destabilization Technology of Waste PEM Drilling Fluid in Bohai Oilfield

In light of the difficulty of solid-liquid separation of waste PEM drilling fluid in the Bohai oilfield, constructing an inorganic-organic flocculation system is proposed and the processing method of destabilization technology is optimized. The biggest influence factor on the flocculation process of PEM drilling fluid was determined by designing an orthogonal test. The flocculation mechanism was researched through single factor optimization, combined with zeta potential and particle size distribution test. The results showed that the most significant factors affecting the flocculation of waste PEM drilling fluid were the dosage of inorganic flocculant CaCl2 and flocculation pH value. When the dosage of inorganic flocculant CaCl2 was 1.2% (w/v), the dosage of organic flocculant SDYJ-2 was 0.05%, the flocculation pH value was 3, and the flocculation time was 5 min, the flocculation technology reached the optimization and then the liquid yield can reach 70.96%. The mechanism of flocculation and destabilization was as follows: the inorganic flocculant of CaCl2 mainly reduced the zeta potential of clay particles through electric neutralization. 1% CaCl2 could reduce the potential mean value of drilling fluid system from -38.1 mV to -32.5 mV, and then decrease the repulsion among suspensions. Through bridging curling and electric neutralization, the organic flocculant of SDYJ-2 can absorb and wrap the clay particles after flocculation destabilization to form a network spatial structure, which made clay particles aggregate into large flocs and particles. D50 can increase by 21.5 times, when the concentration of SDYJ-2 was 0.15%.

Effects of CoMo/γ-Al2O3 Catalysts on Product Hydrocarbon and Phenol Distribution during Hydrodeoxygenation of Oxidized Bio-Oil in a Batch Reactor

Hydrodeoxygenation is an essential process for producing liquid transportation fuels. In this study, the effects of CoMo/γ-Al2O3 catalysts form and loading ratio on the hydrodeoxygenation upgrading of bio-oil were investigated in a batch reactor. Raw bio-oil was first oxidized with hydrogen peroxides and oxone to obtain the oxidized bio-oil with reduced levels of aldehydes and ketones, increasing the organic liquid yield during hydrodeoxygenation by suppressing the coke formation. CoMo/γ-Al2O3 was selected as the catalyst because of its low cost and commercial availability. The effect of the reduction and sulfidation of CoMo/γ-Al2O3 catalyst on the hydrodeoxygenation of the oxidized bio-oil was compared. The effect of the catalyst loading ratio on bio-oil hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalysts was also investigated. The research results showed that the sulfided CoMo/γ-Al2O3 catalyst facilitated the formation of hydrocarbons, while the reduced CoMo/γ-Al2O3 catalyst produced more phenols in the organic liquids. Moreover, a high sulfided catalyst loading ratio promoted the formation of hydrocarbons.

Optimization of Liquid Fuel Production from Microwave Pyrolysis of Used Tyres

Used tyres pose a threat to the environment, especially in developing countries, since the current disposal methods lead to environmental pollution. Pyrolysis liquid from used tyres can be used as a source of fuel to replace petroleum diesel. Microwave pyrolysis is an alternative valorization process that is supposed to save energy and, therefore, is environment friendly. In the current study, microwave pyrolysis was used to produce liquid fuel. Processing variable levels for microwave were power levels of 20, 30, 40, 50, 60, 80, and 100%; the reaction times were 8, 13, 18, 23, and 28 minutes; and the particle sizes were 25, 50, 100, and 200 mm2. Design-Expert 13 was used for data analysis and optimization, and GC-MS was used for chemical composition analysis, while physiochemical properties were tested using standard methods. Response surface methodology (RSM) was used to study the effects of operating variables and identify the points of optimal yields. For microwave pyrolysis, the highest liquid yield of 39.1 wt. % was at 50% power, 18 min reaction time, and particle size of 25 mm2. The yield decreased as the particle size increased. RSM gave conditions for optima in agreement with the experimental results. The calorific value for liquid fuel was 48.99 MJ/kg. GC-MS analysis showed that the oil comprised complex mixtures of organic compounds with limonene, toluene, and xylene as major components. The liquid fuel properties meet the required international standards and can be used as an alternative to diesel fuel.

Pyrolysis of High-Ash Natural Microalgae from Water Blooms: Effects of Acid Pretreatment

Natural microalgae (NA, cyanobacteria) collected from Taihu Lake (Jiangsu, China) were used for biofuel production through pyrolysis. The microalgae were de-ashed via pretreatment with deionized water and hydrochloric acid, and the samples obtained were noted as 0 M, 0.1 M, 1 M, 2 M, 4 M, 6 M, 8 M, respectively, according to the concentration of hydrochloric acid used in the pretreatment. Pyrolysis experiments were carried out at 500 °C for 2 h. The products were examined by various techniques to identify the influence of the ash on the pyrolysis behavior. The results showed that the ash inhibited the thermal transformation of microalgae. The 2 mol/L hydrochloric acid performed the best in removing ash and the liquid yield increased from 34.4% (NA) to 40.5% (2 M). Metal-oxides (mainly CaO, MgO, Al2O3) in ash promoted the reaction of hexadecanoic acid and NH3 to produce more hexadecanamide, which was further dehydrated to hexadecanenitrile. After acid pretreatment, significant improvement in the selectivity of hexadecanoic acid was observed, ranging from 22.4% (NA) to 58.8% (4 M). The hydrocarbon compounds in the liquid product increased from 12.90% (NA) to 26.67% (2 M). Furthermore, the acid pretreatment enhanced the content of C9–C16 compounds and the HHV values of bio-oil. For natural microalgae, the de-ashing pretreatment before pyrolysis was essential for improving the biocrude yield and quality, as well as the biomass conversion efficiency.

Pyrolysis yields of tobacco crop residue as a potential alternative fuel source

This study aims to utilize the tobacco crop residue to generate a high economic value for the energy sector. In general notion, tobacco crop is burned as a conventional fuel at low prices; however, in this research, tobacco crop residue was processed through pyrolysis in the form of pyrolysis products (liquid and solid yields) providing a promising alternative fuel fulfilling the standardized fuel properties. The pyrolysis was conducted at a laboratory-scale real pilot plant experiment at a fixed bed reactor and was operated at temperature of around 350 °C to 650 °C for 2 hours to navigate the most optimum product. Further, the products comprising char (solid yield) and tar (liquid yield) were investigated by measuring their properties, which include heating value, flash point, viscosity, density, and char yields’ morphology. The measurement results indicated that the heating value of tobacco crop residue from pyrolysis process significantly escalated to 300% compared to that of tobacco crop residue before pyrolysis process. Similarly, several tar properties indicated the liquid fuel standard such as kerosene. Additionally, another product in the form of solid yields is proved to be utilized as a smart material besides having a higher heating value over coal, due to the high-quality carbon specifications. However, further processing is encouraged to navigate the possibility of solid yields into activated carbon.

Recovery of Ionic Liquid from Aqueous Phase Pyrolytic Oil: A Simulation Using ASPEN HYSYS V10

Aqueous phase pyrolytic oil is generally considered less important and often discarded as a pyrolysis by-product due to lack of specific applications. Although, recent studies have proposed production of hydrogen via catalytic aqueous and steam reforming from this stream, however, these processes require complex system. Imidazole is one of the major components of aqueous phase pyrolytic oil which can be converted into different products. This study presents a new valorisation strategy of aqueous phase pyrolytic oil into renewable ionic liquid through simulation. A steady state process simulation for recovery of imidazole from aqueous phase pyrolytic oil and subsequent conversion into ionic liquid was developed using ASPEN HYSYS V10 ®. Effects of different operating variables such as feed flow rate, composition and temperature on the imidazole recovery, ionic liquid yield and composition were investigated. The simulation results revealed that high yield of renewable ionic liquid with physicochemical properties comparable to that of commercially available ionic liquids can be produced from aqueous phase pyrolytic oil. This product can be utilised for biomass refining since ionic liquid have been reported to selectively remove hemicellulose and lignin in many biomass related applications such as pre-treatment and characterization.

Conversion of Waste Plastics to Liquid Fuels by Micro-Mesoporous HZSM-5 Catalysts

Three micro-mesoporous HZSM-5 catalysts were synthesized using three different mesoporous templates and studied for the conversion of a model municipal waste plastic mixture to produce liquid fuels of high value. For the comparison, the conversion of an actual waste plastic mixture and HDPE was also studied. The experiments were performed in a batch stirred reactor at three reaction temperatures (350, 375, and 400 °C) and at fixed cold H2 pressure (20 bar), reaction time (60 min), and plastic to catalyst ratio (20:1 by wt.). The micro-mesoporous catalysts produced better activity and selectivity than their parent HZSM-5 catalyst. The catalyst, prepared by combining two different templates, was found to be the most favorable catalyst offering 67.1% liquid yield at 400 °C with actual waste plastic. The best performing catalyst has shown the prospects for commercial applications.

Catalytic Pyrolysis of Municipal Solid Waste: Effects of Pyrolysis Parameters

Burning municipal solid waste (MSW) increases CO2, CH4, and SO2 emissions, leading to an increase in global warming, encouraging governments and researchers to search for alternatives. The pyrolysis process converts MSW to oil, gas, and char. This study investigated catalytic and noncatalytic pyrolysis of MSW to produce oil using MgO-based catalysts. The reaction temperature, catalyst loading, and catalyst support were evaluated. Magnesium oxide was supported on active carbon (AC) and Al2O3 to assess the role of support in MgO catalyst activity. The liquid yields varied from 30 to 54 wt% based on the experimental conditions. For the noncatalytic pyrolysis experiment, the highest liquid yield was 54 wt% at 500 °C. The results revealed that adding MgO, MgO/Al2O3, and MgO/AC declines the liquid yield and increases the gas yield. The catalysts exhibited significant deoxygenation activity, which enhances the quality of the pyrolysis oil and increases the heating value of the bio-oil. Of the catalysts that had high deoxygenation activity, MgO/AC had the highest relative yield. The loading of MgO/AC varied from 5 to 30 wt% of feed to the pyrolysis reactor. As the catalyst load increases, the liquid yield declines, while the gas and char yields increase. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Highly selective skeletal isomerization of cyclohexene over zeolite-based catalysts for high-purity methylcyclopentene production

Cyclohexene skeletal isomerization towards methylcyclopentene is an economically favorable process due to the higher added value of the product. Traditional oxide-based catalysts face the challenge of achieving both high activity and stability. In this work, cyclohexene skeletal isomerization is achieved under mild conditions over designed zeolite-based catalysts with 96.8 wt.% liquid yield, 95.8 wt.% selectivity towards methylcyclopentene and satisfactory stability for multiple runs. The favorable performance is attributed to the unique acidic, structural and morphological features of the optimized cobalt/NaUZSM-5 catalyst. Further experimental data and DFT studies suggest that a carboncationic mechanism might be followed and that the reaction mainly occurs within the internal pores of the zeolite structures.

Comparative Investigation of Yield and Quality of Bio-Oil and Biochar from Pyrolysis of Woody and Non-Woody Biomasses

This study investigated the quantitative and qualitative attributes of liquid product and biochar obtained from pyrolysis of woody biomass (rubberwood sawdust (RWS)) and non-woody biomasses (oil palm trunk (OPT) and oil palm fronds (OPF)). The prepared biomass was pyrolyzed at temperatures of 500 °C, 550 °C, and 600 °C by using an agitated bed pyrolysis reactor, and then the yields and characteristics of liquid product and biochar were determined. The results showed that liquid product and biochar yields were in the respective ranges of 35.94–54.40% and 23.46–25.98% (wt.). Pyrolysis of RWS at 550 °C provided the highest liquid yield. The energy content of the water free liquid product was in the range 12.19–22.32 MJ/kg. The liquid product had a low pH and it mainly contained phenol groups as indicated by GC-MS. The biochars had high carbon contents (75.07–82.02%), while their oxygen contents were low (14.22–22%). The higher heating value (HHV) of biochar was in the range 26.42–29.33 MJ/kg. XRF analysis revealed that inorganic elements had higher contents in biochar than in the original biomass. The slagging and fouling indexes of biochar were also different from those of the biomass. High carbon content of the biochar confirms potential for its use in carbon sequestration. The specific surface of biochar was lower than that of biomass, while the average pore diameter of biochar was larger than for raw biomass as revealed by BET and SEM. These results on liquid product and biochar obtained from RWS, OPT, and OPF demonstrate that they are promising feedstocks for biofuels and other value-added products.