Effect of oil type on the recovery of coal fines from coal waste slurry by the oil agglomeration process

The coal fines from slurry waste discarded from the Jamadoba coal preparation plant were used for the recovery of significant energy value coal fines. The effect of oil type was investigated using different oils (edible oil and nonedible oil) at constant pulp density (PD) and agglomeration time (AT) and varying oil dosages. (ODs) The results were evaluated based on % organic matter recovery (% OMR) and % ash rejection (% AR).     

Recovery of coal values from the refuse pond coal slurry using flotation

The objective of the present investigation is to explore the possibility of recovery of coal values from the tailing dump, so as to recover the coal values from the discarded product for sustainable development and optimum utilization of coal reserves. The influence of two important variables which commonly fluctuate in the operating plants, such as feed solid concentrations and collector dosage, has been varied and analyzed to study their influence on flotation performance. Among the variables studied, the pulp density of 8% of feed solid concentration was found to be most suitable level. A collector dosage of 0.105 kg/ton of coal gave the best result in term of ash reduction.     

Cleaning of high sulfur Indian coal by oil agglomeration and leaching

The present paper reports an attempt for cleaning of high sulfur Indian coal with two consecutive steps of oil agglomeration at ambient temperature followed by leaching at various conditions. The physico-chemical characterizations of the raw and treated coal samples were carried out by using Fourier transform infrared (FTIR), FESEM, Thermogravimetric analysis and Differential Thermal Analysis (TGA-DTA), and petrographic techniques to assess the product quality. The petrographic and FTIR spectral analyses reveal reduction in different forms of sulfur contents in coals by the use of oil agglomeration and leaching. Scanning electron microscope morphology of the treated coal samples are attributed to the occurrence of the cavitations in the coal structure.     

Effects of ash removal by agitated aqueous washing and sedimentation on the physico-chemical characteristics and fast pyrolysis of trommel fines

A pre-treated trommel fines feedstock (DPT) with 35.1 wt% ash content and particle size range of 0.5–2 mm was processed through two (100% distilled water and 1% surfactant in distilled water) aqueous agitated washing and sedimentation procedures for ash reduction prior to fast pyrolysis in a bubbling fluidized bed reactor. The washing process led to more than 36% reduction in the ash/inorganic contents of the DPT feedstock and yielded about 78 wt% of organic-rich feedstocks denoted as WPT1 and WPT2. Characterisation and fast pyrolysis of all three feedstocks was carried out to evaluate the effect of the washing process on their physico-chemical characteristics and yields of fast pyrolysis products. Results showed that the ash reduction led to increase in the volatile matter contents of the washed feedstocks by 20%, while reducing nitrogen contents. In addition, fast pyrolysis of the feedstocks showed improved yield of liquid and gas products, with a dramatic reduction of reaction water, indicating that the ash removal reduced the catalytic effect of the ash on water formation during the fast pyrolysis process. The major organic compounds in the liquid products included phenols and furans from biogenic fraction of the feedstock as well as aromatic hydrocarbons such as those obtained from pyrolysis of plastics. More importantly, the overall energy yields from the fast pyrolysis process increased by over 35% after washing the feedstock, with washing with only distilled water alone giving the highest energy yield of 93%. Hence, coupling the water-washing ash reduction process with fast pyrolysis appeared to be a suitable technology for valorising feedstocks with high ash contents such as trommel fines for energy and chemicals.     

Energy recovery by fast pyrolysis of pre-treated trommel fines derived from a UK-based MSW material recycling facility

In this experimental study, a physically pre-treated trommel fines feedstock, containing 44 wt% non-volatiles (ash and fixed carbon) and 56 wt% volatile matter (dry basis), was subjected to fast pyrolysis to recover energy from its organic load, using a 300 g h⁻¹ bubbling fluidized bed (BFB) fast pyrolysis rig. A physical pre-treatment method (including crushing, grinding and sieving) was used to prepare a 0.5–2 mm sized trommel fines feedstock to make it suitable for fast pyrolysis in the BFB reactor. Experimental results from the fast pyrolysis process showed that the highest yield of organic liquid was obtained at around a temperature of 500 °C. However, both char and gas yields increased dramatically at temperatures above 500 °C, as a result of enhanced cracking of organic vapours, which reduced the yield of liquid products. Overall, energy recovery from the pyrolysis products (liquid and gas products as well as char pot residues) ranged from 63 to 70%, generally increasing with temperature. A large proportion of the high ash content (36 wt%) of the feedstock was found in the char pot (>62%), while smaller proportions were found in the reactor bed and some liquid products. The char pot ash residues composed mostly of non-hazardous earth materials and may be applied in bulk construction materials e.g. cement manufacture. Although, there was no problem with the pyrolysis rig during 1 h of operation, longer periods of operation would require periodic removal of accumulated solid residues and/or char pot modification to ensure continuous rig operation and process safety.     

Recovering clean low-rank coal using shale oil as a flotation collector

Shale oil (SO) was adopted as flotation collector to recover clean low-rank coal. Gas chromatography-mass spectrometry, flotation, X-ray photoelectron spectroscopy and contact angle measurements were performed to identify the chemical constituents and flotation performance of SO, and the surface properties of low-rank coal. The results indicated that the long-chain hydrocarbon and high viscosity of SO may lead to the higher combustible matter recovery and lower ash content of clean coal. The adsorption of SO significantly enhanced the carbon-bearing content and decreased the C?O content, which was favorable to enhance the hydrophobicity, and thus improve the flotability of low-rank coal.     

The effect of sludge from coal to oil process on the stability of coal/sludge water slurries

Sludge produced from coal to oil process contains larger content of tar, phenols, ammonia components, and ashes. It cannot be treated by using traditional disposal methods as landfill or incineration. A promising solution is to blend sludge with coal for preparation of sludge/coal-water slurries. The new slurry fuels could be used in commercial gasifiers for syngas generation. In this process, the first goal is to form a stable slurry. In the research project, the addition of sludge on the stability of coal-water slurries was investigated. Results show that the addition of sludge can improve the static stability for slurries prepared by lean coal, coking coal, and lignite. The effect on stability of coking coal-water slurry is the most significant. The proportion of sludge to lean coal added in the slurry can be maintained at 10% to 15%.     

炼厂瓦斯气的回收利用及自动控制

简要介绍了对炼厂瓦斯气进行回收利用的手段和设备,并对其中的关键技术－火炬设施的自动控制作了较为全面的分析。指出该技术无论是从环保安全还是从节能降耗方面,均具有极佳的推广应用价值。     

Agglomeration of Pakistani coal (Lakhra) using diesel oil

The upgradation of a low quality coal enables it suitable for wider applications. The Lakhra coal (Pakistan) belongs to the lignite coal category. This study investigates the agglomeration technique for beneficiation of Lakhra coal using diesel oil as an agglomerant. Three parameters were investigated such as the solid–liquid ratio, residence time, and shear velocity. Characterization of the Lakhra coal before and after agglomeration was carried out in order to determine its volatile matter, fixed carbon, ash and sulfur contents, and gross calorific value. According to the results, agglomerates contained fixed carbon 35.63%, volatile matter 42.21%, gross calorific value (GCV) 5570.6 kcal/kg, ash 17.07%, and sulfur 4.03%. The ash and sulfur reductions were 42.3% and 58.4%, respectively, suggesting significant reduction in ash and sulfur compared to the original coal. The clean coal, resulting from this cleaning process, is a good grade product which may be valued as a good fuel source for any coal fired utility.     

Agglomeration of Makarwal coal using soybean oil as agglomerant

The study was carried out for beneficiation of Makarwal coal using soybean oil as agglomerant. The effect of six parameters – pH, mesh size of coal particles, slurry ratio, stirring speed, soybean oil concentration, and time of agglomeration – was investigated to reduce ash and sulfur from Makarwal coal and to enhance the gross calorific value. In the cleaned product obtained after the agglomeration process, the gross calorific value was increased from 4900 to 7115 Kcal/kg. The ash of agglomerates was reduced from 30% to 7.5% and sulfur was reduced from 5.4% to 2.0% The optimum operating conditions were concentration of soybean oil 10 mL, pH 9, stirring speed 2800 rpm, mesh size 200, coal to water ratio of 15:450 (W/V), and time of agglomeration 20 min. Significant reduction in ash and sulfur showed the effectiveness for agglomeration of Makarwal coal using soybean oil as the agglomerant. The final product thus obtained may be used efficiently in various energy recovery schemes.     

Energetic and exergetic analysis of waste heat recovery from a microturbine using organic Rankine cycles

This article examines the exhaust waste heat recovery potential of a microturbine (MT) using an organic Rankine cycle (ORC). Possible improvements in electric and exergy efficiencies as well as specific emissions by recovering waste heat from the MT exhaust gases are determined. Different dry organic working fluids are considered during the evaluation (R113, R123, R245fa, and R236fa). In general, it has been found that the use of an ORC to recover waste heat from MTs improves the combined electric and exergy efficiencies for all the evaluated fluids, obtaining increases of an average of 27% when the ORC was operated using R113 as the working fluid. It has also been found that higher ORC evaporator effectiveness values correspond to lower pinch point temperature differences and higher exergy efficiencies. Three different MT sizes were evaluated, and the results indicate that the energetic and exergetic performance as well as the reduction of specific emissions of a combined MT‐ORC is better for small MT power outputs than for larger MTs. This article also shows how the electric efficiency can be used to ascertain under which circumstances the use of a combined MT‐ORC will result in better cost, primary energy consumption, or emission reduction when compared with buying electricity directly from electric utilities. Copyright © 2012 John Wiley & Sons, Ltd.     

Biodiesel production from waste sunflower oil by using Amberlyst 46 as a catalyst

In this study, simultaneous transesterification and esterification of high acid value sunflower oil to fatty acid methyl esters was studied using Amberlyst 46 as a heterogeneous catalyst. The influence of reaction conditions such as molar ratio of methanol/oil, reaction time, and reaction temperature was investigated. The highest fatty acids methyl esters yield of 75.8% was obtained in presence of 6 wt% oleic acid content under reaction conditions of 20 wt% Amberlyst 46 catalyst amount, 6/1 methanol/oil molar ratio, reaction temperature of 130°C, and reaction time of 10 h.     

Production of diesel-like fuel from waste engine oil by pyrolitic distillation

The aim of this study is to obtain diesel-like fuel from waste lubrication engine oils by pyrolitic distillation method, which can be used in diesel engines. With this aim in mind, waste engine oil is collected in a tank, and it is purified from contaminants such as dust, heavy carbon soot, metal particles, gum-type materials and other impurities by filtering in the process prepared earlier. To investigate effects of additives known as sodium carbonate (NaCO₃), zeolite and lime (CaO) on density, viscosity, flash point, sulfur content, heating value and distillation temperature, the purified oil samples are blended separately with additives having mass basis of 2%, 4%, 6%, 8% and 10%. The mixed samples are exposed to pyrolitic distillation process to produce fuels to be used in engines. Thermal and physical properties of the produced fuels such as density, flash point, viscosity, sulfur content, heating value and distillation temperatures are examined. From these results, the CaO with a ratio of 2% has the highest effect on decreasing of sulfur content of the waste engine oil and on acquiring the most suitable distillation temperatures close to values of a diesel fuel. Diesel-like fuel (DLF) is obtained as 60% of the waste lubrication engine oil.     

A comparison of ignition characteristics of slurry fuels prepared using coal processing waste and finely divided coal

The scientific novelty of the research is that for the first time differences in the conditions and characteristics of the ignition and burning of droplets of slurries prepared on the basis of coals and waste from their enrichment have been established. The practical significance of the research results is that they illustrate the prospects of utilization of the numerous coal enrichment wastes by combustion in the composition of aqueous slurries with the generation of a rather large amount of energy and a relatively small negative environmental impact. The most significant characteristics were compared: the limiting (minimum) temperature; the ignition delay times; the maximum combustion temperature; the concentration of the main gas anthropogenic emissions. It has been found that fuel mixtures prepared from wet waste of coal flotation are characterized by higher inertia and ignition temperatures compared to slurries with high-quality coal dust. However, the established differences considering the availability and low cost of filter cakes illustrate the prospects of waste derived fuel combustion. The combustion heat of the investigated slurries based on coal and filter cake with addition of petroleum products differs by no more than 5–30%. The average difference between the duration of ignition for fuel droplets based on dust and filter cake of coking and low-caking coals is about 20%. At that the addition of waste turbine oil (10% wt.) into the filter cake reduces the duration of ignition by 12–25% and the ignition temperature – by 10–15 °C without a significant increase in anthropogenic gas emissions. The difference between the minimum ignition temperatures of coal and waste coal based slurries was from 10 °C to 80 °C. On environmental and economic indicators, coal waste is more attractive than coal.     

Optimization of biodiesel production from waste cooking oil using waste bone as a catalyst

This work determined the association between several parameters of biodiesel production from waste cooking oil (WCO) using waste bovine bone (WBB) as catalyst to achieve a high conversion to fatty acid methyl ester (%FAME). The effect of three independent variables was used as the optimum condition using response surface methodology (RSM) for maximizing the %FAME. The RSM analysis showed that the ratio of MeOH to oil (mol/mol), catalyst amount (%wt), and time of reaction have the maximum effects on the transform to FAME. Moreover, the coefficient of determination (R²) for regression equations was 99.19%. Probability value (P < 0.05) demonstrated a very good significance for the regression model. The optimal values of variables were MeOH/WCO ratio of 15.49:1 mol/mol, weight of catalyst as 6.42 wt%, and reaction time of 128.67 min. Under the optimum conditions, %FAME reached 97.59%. RSM was confirmed to sufficiently describe the range of the transesterification parameters studied and provide a statistically accurate estimate of the best transform to FAME using WBB as the catalyst.     

大中修机车旧机油回收再利用

介绍了大中修机车旧机油回收再利用的过程,通过对旧机油回收、储存、使用等问题的分析,说明具有很好的经济效益和可操作性。     

氨基磺酸非均相催化菜籽油及废油脂制备生物柴油

采用正交试验和单因素试验的方法研究了氨基磺酸催化菜籽油及废油脂与甲醇的酯交换过程,考察了醇油物质的量比、催化剂用量、反应温度和反应时间对反应收率的影响。结果表明:菜籽油酯交换的最佳反应条件为醇油物质的量比6∶1,氨基磺酸用量为原料油质量的1.0%,反应温度60℃,反应时间20 min,此工艺条件下,脂肪酸甲酯的收率达到95.6%;废油脂酯交换的最佳反应条件为醇油物质的量比8∶1,氨基磺酸用量为原料油质量的1.0%、反应温度65℃,反应时间30 min,此工艺条件下,脂肪酸甲酯的收率达到87.5%。利用红外光谱表征了菜籽油和生物柴油的结构,气相色谱分析了生物柴油的组成。     

Bitumen recovery from Buton oil sands using a surfactant under the effect of ultrasonic waves

A new process for ultrasonic-assisted surfactant extraction of bitumen from Buton oil sands is performed. The microstructure and composition of Buton oil sands are characterized. The results demonstrated that its inorganic mineral contains 95.2% calcite and the particle size is mostly 2–5 μm. The extraction experiments show that the bitumen recovery ratio of nonylphenol polyoxyethylene ether (NP-12) is 91.6%. Ethylene oxide number and hydrophile-lipophile balance have significant effects on the bitumen recovery ratio. In addition, the bitumen recovery ratio of NP-12 can still reach 90.2% after being recycled five times.     

A perspective on incorporation of glycerin purification process in biodiesel plants using waste cooking oil as feedstock

In biodiesel production through transesterification, glycerin is produced as a valuable co-product. Some biodiesel plants have incorporated a glycerin purification process since the beginning of operations. The objective of this study is to evaluate the benefits of the incorporation of a glycerin purification process to a biodiesel plant where has already been constructed without the initial consideration of including an extra process for glycerin. A cost–benefit analysis is applied to evaluate the potential benefit from the incorporation of this process, in cases of a high plant cost and a low plant cost, with and without a glycerin facility installation. Our results show that the installation of a glycerin purification process could benefit a biodiesel plant through glycerin recovery and a decrease in wastewater treatment cost. The current downward trend in the market price of glycerin could be offset by encouraging the development of new applications for glycerin in order to expand the existing market and to stabilize the market price. However, biodiesel plants using waste cooking oil in Japan still need government subsidy to sustain their business activity.