Extraction of spent bleaching materials

Large amounts of oils and fats are recoverable from spent bleaching materials. On account of the extreme fineness of the bleaching materials special equipment is required. A solvent extraction process, plant and equipment are described with operating costs and results given.     

Oil recovery from spent bleaching earth and disposal of the extracted material

Methods for recovering oil from spent bleaching earth are described. Blowing steam and circulating hot water through spent bleaching earth reduce its oil content to only ca. 25% and 20%, respectively. Mixing the cake with milled oilseed may spoil the fresh oil. Hexane extraction of spent earth with hexane is economically feasible for expensive and relatively stable oils only. Because of its simplicity and low cost, extraction with an aqueous solution of soda and salt is economically feasible. The problems with respect to the disposal of the extracted material are discussed.     

Decolorisation of crude palm oil by acid-activated spent bleaching earth

Regeneration of spent bleaching earth by acid activation and heat treatment has been investigated. Spent bleaching earth was activated by H₂SO₄ of various concentrations (1–40%) and heat treated at 120°C–350°C. The experimental results indicate that treatment of spent bleaching earth with 10% H₂SO₄ at 350°C produced a material which was most effective in removing coloured pigments from crude palm oil. Subsequent experiments were conducted using this particular acid-treated spent bleaching earth. Various parameters which affect the sorption process were studied. They include initial crude palm oil concentration, sorbent dosage and temperature. Applicability of both the Freundlich and Langmuir isotherms to the acid-treated spent bleaching earth–palm oil hexane miscella system indicates that both physiosorption and chemisorption were involved in the sorption process. Measurements of various quality parameters of bleached and crude palm oils were carried out. They include Lovibond Colour index, carotene content, peroxide value, free fatty acid, fatty acid composition and iodine value. The results show that the bleached palm oil retained good oil quality after the decolorisation process using 10% acid-treated spent bleaching earth with a Lovibond Colour of 6·4. © 1998 SCI     

Ammonia combustion at elevated pressure and temperature conditions

This numerical study examines the combustion characteristics of premixed ammonia-air mixtures, with equivalence ratios around unity, at elevated pressure and temperature conditions which are encountered in SI engine operations. The laminar burning velocity, final flame temperature and species concentrations were determined using Konnov’s mechanism [18]. A flat, freely propagating flame was considered. Both equivalence and compression ratios have an important impact on both the laminar burning velocity and the adiabatic flame temperature. Furthermore, only the variation of the equivalence ratio has a major impact on the formation of nitrogen monoxide. It was found that the compression ratio and the final temperature do not have a significant impact on NO yields for equivalence ratios above unity.     

Regeneration of spent bleaching earth and its adsorption of copper (II) ions from aqueous solutions

This study was designed to provide a comprehensive investigation into heat and acid reactivation of spent bleaching earth (SBE) and adsorption of Cu(II) ions from aqueous solutions. Heat treatment was the master variable in SBE regeneration. Dilute acid treatment did not constitute an effective SBE reactivation protocol for this purpose. Solvent extraction of residual oil using excess methylethyl ketone followed by heating at 370 °C was, therefore, the most effective reactivation procedure. Highly adsorptive materials with > 98% removal of Cu(II) ions from solution were obtained. Thus, > 80% Cu adsorption was reversible at SBE silicate sites because of their higher proportion in the adsorbent.     

High pressure FIR-spectroscopy on polyethylene at elevated temperature

Summary The temperature and pressure dependence of the translational B_1u-lattice vibration has been determined in the pressure range of 7 kbar and a temperature range of almost 200 K from room temperature upwards. For some pressure values the Grüneisen Parameter has been evaluated as a function of temperature. A detailed discussion is given for a step in the (T)-curves at elevated pressure.     

废白土榴莲壳粘土生物炭的制备及对Cr(VI)的吸附

以废白土与榴莲壳为原料制备了粘土生物炭吸附剂(spent bleaching earth biochar,SBEC)、以废白土为原料制备了粘土炭基吸附剂(spent bleaching earth,SBE)吸附废水中的Cr（VI）。用比表面积分析、SEM、XRD、FTIR对吸附剂进行了表征。考察了溶液初始pH、Cr(VI)溶液浓度、吸附剂投加量、吸附时间和吸附温度分别对吸附Cr(VI)的影响。25℃下pH为3时、SBEC 投加量为0.5g/L、Cr(VI)初始浓度为100mg/L、吸附时间120min,SBEC对Cr(VI)去除效率最高为86.1%,SBE则在pH为2去除效率最高为52.5%。SBEC、SBE对Cr(VI)的吸附过程符合准二级动力学模型,SBEC吸附过程符合Freundlich模型,SBE则与Langmuir吸附等温线模型较符合;吸附行为是自发吸热过程。经过5次吸附-脱附后,SBEC对Cr(VI)的去除率达58.8%。     

A low cost adsorbent from spent bleaching earth. I—the selection of an activation procedure

The conversion of a spent filter cake from the edible oil industry to a heterogeneous clay-carbon adsorbent is reported. Chemical and physical activation procedures have been applied and the resulting materials screened by carbon content and aqueous phenol uptake. Full adsorption isotherms are plotted for sorbents with high phenol capacities and their adsorptive behaviour is modelled to the Freundlich and Langmuir isotherms.     

废白土榴莲壳粘土生物炭的制备及对Cr(VI)的吸附

以废白土与榴莲壳为原料制备了粘土生物炭吸附剂(spent bleaching earth biochar,SBEC)、以废白土为原料制备了粘土炭基吸附剂(spent bleaching earth,SBE)吸附废水中的Cr（VI）。用比表面积分析、SEM、XRD、FTIR对吸附剂进行了表征。考察了溶液初始pH、Cr(VI)溶液浓度、吸附剂投加量、吸附时间和吸附温度分别对吸附Cr(VI)的影响。25℃下pH为3时、SBEC 投加量为0.5g/L、Cr(VI)初始浓度为100mg/L、吸附时间120min,SBEC对Cr(VI)去除效率最高为86.1%,SBE则在pH为2去除效率最高为52.5%。SBEC、SBE对Cr(VI)的吸附过程符合准二级动力学模型，SBEC吸附过程符合Freundlich模型，SBE则与Langmuir吸附等温线模型较符合；吸附行为是自发吸热过程。经过5次吸附-脱附后,SBEC对Cr(VI)的去除率达58.8%。     

Regeneration of a spent bleaching earth and its reuse in the refining of an edible oil

A spent bleaching earth from an edible oil refinery has been regenerated by thermal processing followed by washing with a solution of hydrochloric acid. Optimal regeneration conditions have been controlled by decolorization tests of a degummed and neutralized crude edible oil. Optimal values (temperature: 500 °C, carbonization time: 1 h, HCl concentration: 1 M ) gave a material as efficient as a virgin bleaching earth. The percentage uptake of chlorophyll derivatives and β‐carotenoids calculated at 410 and 460 nm, are respectively 92.8 and 95% for an oil processed by the regenerated spent bleaching earth, against 77.4 and 92.7% for the same oil processed by a commercial virgin bleaching earth. The results obtained after decolorization of an edible oil with a regenerated spent bleaching earth indicate that during the process, the resultant oil did not undergo any changes in the iodine value, the free fatty acid content and the saponification value. © 2000 Society of Chemical Industry     

以废白土为原料制备生物柴油及其资源化利用

生物柴油是一种清洁可再生能源,正受到越来越多的重视与关注。推动生物柴油技术产业化应用的关键是降低生产成本。廉价原料、高效催化剂、新工艺与设备等是解决问题的重要途径,而发展廉价原料应是首选。油脂厂产生的废白土含油量高达20%~40%,若将其回收用以制备生物柴油既是廉价原料也可实现废弃物的资源化利用。本文综述了以废白土为原料制备生物柴油的研究进展,主要包括一步法和两步法工艺。两步法较为成熟,但工艺复杂,溶剂用量大。一步法流程简单,成本较低,但反应时间长,催化剂分离困难。因此,未来须着力于在一步法工艺基础上,探索快速、高效且催化剂易于回收的反应工艺。     

A low cost adsorbent from spent bleaching earth. II—optimisation of the zinc chloride activation procedure

A set of optimised preparative parameters has been established for the zinc chloride activation of spent bleaching earth. Continuous volumetric nitrogen adsorption and aqueous phase phenol isotherms are used to characterise a range of adsorbents prepared using the rotary furnace. A structural model is proposed for these clay-carbon materials and the key factors affecting their adsorptive capacity are discussed.     

Regeneration of spent polymer resins in oily water treatment systems by application of nanoemulsion

In step production of oil wells, along with oil, also produces a large volume of water oily, which must be properly treated for disposal. Several absorbent materials have been developed and are highly effective for this purpose. However, they need regeneration when they reach saturation, because their discharge after each saturation cycle makes the process unfeasible from the cost and environmental standpoints. In this study, we investigated the efficiency of regenerating a methyl methacrylate‐divinylbenzene polymer resin spent in a system for continuous treatment of oily wastewater, in loco. The regeneration fluid used was an O/W nanoemulsion, which contain only 8% of environmentally friendly solvent and 80% of synthetic marine water. A kinetics desorption study of oil saturated resin was performed to identify the best times for desorption using the nanoemulsion. After one cycle of saturation, cleaning and resaturation, was observed that regeneration efficiency in continuous process of around 40%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42050.     

Morphology of high-density polyethylene pipes stored under hydrostatic pressure at elevated temperature

The morphology of unimodal and bimodal high-density polyethylene (HDPE) pipes during a hydrostatic pressure test was studied in detail using ¹H solid-state NMR. Characterizing the changes of the molecular network during such a test is of key importance for understanding the long-term properties of different HDPE pipe grades. The changes in amount, thickness, and molecular mobility of the crystalline phase, the interface, and the amorphous phase of the two pipe grades with the storage time have been quantified for the first time. The most sensitive microscopic parameter to storage is the molecular mobility of the amorphous phase, with the strongest changes shown by the unimodal HDPE. The density of the tie-molecules is not the main factor controlling the very different behavior of the two pipe grades, but rather it is the density of the entanglements. The NMR results offer unprecedented insights into the changes in the molecular network and support existing deformation models.     

Hydrodynamics and flow regime transition study of trickle bed reactor at elevated temperature and pressure

The hydrodynamics in a trickle bed reactor (TBR) in non-ambient conditions are studied for air-water and air-acetone (pure organic liquid of low surface tension) systems. A flow map experiments for air-water and air-acetone systems are performed in a pilot plant reactor of 0.05 m i.d. and 1.25 m height. It has been demonstrated from the experimental results that the pressure drop tends to increase with increasing superficial gas and liquid velocity and reactor pressure, while it tends to decrease with increasing bed temperature. The results also show that the dynamic liquid holdup increases with increasing liquid velocity and decreases with increasing superficial gas velocity, reactor pressure and bed temperature. The dynamic liquid holdup and pressure drop values are obviously higher than those measured for air-water system at the same fluid fluxes, reactor pressure and bed temperature due to the surface tension effects. For higher reactor pressure and temperature, the trickle to pulse transition boundary shifts towered higher superficial velocities of both gas and liquid.     

Effect of aggregate and water to cement ratio on concrete properties at elevated temperature

Properties of concrete during and after fire exposure are of significant importance for serviceability and rehabilitation of buildings. This article presents an experimental investigation on the effects of elevated temperature on physical and mechanical properties of concrete made using two types of locally available coarse aggregates (crushed and wadi aggregates) and water‐to‐cement (w/c) ratios of 0.50 and 0.70. Temperature range from 200 °C to 1000 °C was used with intervals of 200 °C. Test results indicate that the weight of concrete reduced with increase in temperature. This reduction was quite sharp beyond 800 °C. Minor spalling was observed in concrete with Wadi aggregates at temperatures beyond 800 °C. The results also reveal that relative strength of concrete decreased as exposure temperature increased. The effect of high temperatures on the strength of concrete was more pronounced in concrete with Wadi aggregates. w/c ratio had insignificant effect on weight loss after exposure to elevated temperatures, but it increased the rate of strength degradation irrespective of aggregate type used. Comparison of results with Eurocode (EC‐2) and American Concrete Institute (ACI) standards indicate that the concrete with both aggregate types can satisfy the limits of siliceous aggregates set by ACI, but concrete made with Wadi aggregates with w/c ratio of 0.50 failed to satisfy limits of EC‐2. Copyright © 2015 John Wiley & Sons, Ltd.     

Extraction of coal through dilute alkaline hydrolytic treatment at low temperature and atmospheric pressure

Assam coal was extracted with ethylenediamine (EDA) using batch as well as Soxhlet techniques. It was found to be further extractable in EDA after a first extraction step. Stepwise extraction of coal in EDA resulted in 44% extraction. Alkali treatment enhanced the extractability of coal in EDA. Two step (1.5%) aqueous alkali treatment followed at each step by EDA extraction, resulted in 50% extraction of coal. Various solvents were tried in the aqueous alkali treatment of coal. EDA, tetralin, phenol, quinoline, ethanol and butanol were found to give good results. The use of Na₂CO₃ and Ca(OH)₂ along with NaOH in the alkali treatment did not improve the extractability of the coal. Nonaqueous alkali treatment of coal in different solvents also resulted in an enhanced extraction. Phenol, tetralin and pyridine were found to be good reaction solvents for the treatment of coal using solid NaOH in these solvents.     

Extraction of coals through dilute alkaline hydrolytic treatment at low temperature and ambient pressure

Assam and Talcher (bituminous) coals have been subjected to batch aqueous alkali treatment followed by extraction. It has been shown that alkali treatment increased extractability and reactivity of coal. Use of 1.4% aqueous sodium hydroxide was found to be capable of rendering about 40–50% coal extractable in ethylene diamine in two alkali treatments followed by extractions. Semibatch operation yielded about 26–33% extractable coal, and extraction data were found to be comparable with those obtained in batch degradation via a single alkali treatment. Of the solvents studied, polar and basic solvents were found to be the most effective.     

Extraction increase of coals treated with alcohol-sodium hydroxide at elevated temperatures

Taiheiyo coal has been reacted in an autoclave with sodium hydroxide in ethanol. The extractability of the product with pyridine and ethanol increased remarkably as either the reaction temperature or the sodium hydroxide concentration rose. Under the same reaction conditions, the younger the coal the greater the extraction. The main reaction is hydrolysis, but other subsidiary reactions are also taking place. From a blank test, ethanol was found to react almost quantitatively with sodium hydroxide and water to produce sodium acetate and hydrogen gas. In the case of coal the weight of hydrogen produced was smaller than in the blank test, and this difference is ascribed to the consumption of hydrogen by coal on hydrogenation. In the i.r. spectra, bands of methyl and carbonyl absorption appear, which may possibly be explained by the addition of -COCH₃, or by hydrogenation of phenyl nuclei to produce a cyclohexanone-type compound.     

Solvent extraction of fatty acids from natural oils with liquid water at elevated temperatures and pressures

The use of liquid water at elevated temperatures and pressures as an extractive solvent for separating mixtures of compounds which occur in natural oils has been studied. A southern pine tall oil and a distillate from the deodorization of soybean oil were extracted with liquid water at temperatures from 298 to 312°C and pressures between 103 and 121 bar. Results indicate that water can be used to extract fatty and resin acids from crude tall oil to obtain a product with a high acid content that produces less pitch during distillation. The process can also be used to extract fatty acids from vegetable oil deodorizer distillate.