Experimental study on the coal tar hydrocracking process in supercritical solvents

In order to find the optimal operating parameters in high-temperature and low-temperature coal tar hydrocracking processes and to maximize the light oil yields, experimental studies have been carried out in a one-stage reactor in supercritical solvents. Xylene and gasoline were used as supercritical solvents to investigate their effects on the light oil yields. The results show that gasoline was more suitable as a supercritical solvent and that a suitable ratio of gasoline solvent to coal tar could result in higher light oil yields in both high- and low-temperature coal tar hydrocracking processes. The effects of different operating parameters, including temperature, hydrogen pressure, catalyst, and residence time, on light oil yield were tested. It was found that the yields of light oil from the two coal tar hydrocracking processes varied with the operating parameters in a similar manner. However, different values of the operating parameters gave rise to the maximum yields of light oil from the respective processes.     

Supercritical extraction of scrap tire with different solvents and the effect of tire oil on the supercritical extraction of coal

Scrap tires are a growing environmental problem because they are not biodegradable. In this investigation, supercritical extraction of scrap tire and co-processing of coal with tire oil were studied. In the first stage, tires were extracted at 400 °C with a number of different solvents. The effects of the hydrocarbon and polar solvents used under the supercritical extraction conditions on the conversion and oil product of tire were determined, and it was observed that all volatile organic material of the scrap tire was converted to the liquid or gas product. In the second stage, coal and supercritical extracted tire oil (SCETO) samples were extracted with different solvents using various tire oil/coal ratios. In general, the use of tire oil generated an improvement for coal conversion. Further, the oil yield was higher than those of coal alone runs. The SCETOs were characterized using spectroscopic (FTIR) and chromatographic analytical techniques (GC–MS). GC–MS, and FTIR results showed that the oils are mainly comprised of alkyl aromatic species. A significant amount of alkyl-substituted phenol compounds was also found to be present in the oils.     

Alkali-assisted coal extraction with polar aprotic solvents

Coal extraction experiments were conducted using a coal, containing ca. 10% ash, from the Tshikondeni mine in South Africa. This coal dissolves only to a limited extent in pure polar aprotic solvents such as dimethylformamide (DMF) and N-methyl-2-pyrrolidinone (NMP). However, the addition of a strong base, e.g. sodium hydroxide (NaOH) or sodium tert-butoxide increased the degree of coal dissolution in these organic solvents. Depending on the extraction conditions, carbon extraction efficiencies of up to 90% were obtained. Carbon precursor material was recovered from the solution as a gel by precipitation with water. Ash content was reduced from 10% in the coal to less than 1.6% in the coal extracts. Sodium sulfide (Na₂S) addition further reduced ash content and aided the recovery of carbon precursors that led to graphitizable cokes but the degree of extraction was significantly reduced.     

Supercritical gas extraction of coal with hydrogen-donor solvents

An investigation of the effect of a hydrogen-donor component in the solvent used for supercritical gas extraction was undertaken. Extraction of three Australian coals with toluene, with decalin and with these solvents containing small amounts of tetralin was investigated. There was a significant improvement in conversion by addition of 5% tetralin to the solvent. Other hydrogen donors were also effective. The improvement in conversion was shown to be due to hydrogen donation rather than to a change in the physical properties of the solvent. The increase in conversion was greater for a brown coal than for a bituminous coal of the same hydrogen to carbon atomic ratio. The pre-asphaltene content of the extract increased with conversion.     

煤的超临界流体抽提研究进展

超临界流体抽提技术是一项新型、绿色、环保的技术,超临界流体抽提技术应用于煤的目的分为超临界条件下气化制氢,超临界条件下脱除杂质和超临界条件下煤的液化3个方面,综述了超临界流体抽提技术应用于煤的研究进展,并着重论述了该技术应用于煤液化的研究进展,指出了今后的研究方向。     

煤焦油超临界流体提取的研究进展

超临界流体抽提技术是一项新型、绿色、环保的技术,超临界流体抽提技术应用于煤焦油研究的主要目的分为超临界条件下提取其中成分,使煤焦油轻质化,本文介绍了超临界流体抽提技术应用于煤焦油的研究进展,指出了今后的研究方向.     

煤焦油馏分微波萃取神府煤热解液体产物的研究

为提高煤在萃取过程中的转化率,考察微波辅助萃取煤的工业化可行性。在微波辅助下,以神府低温煤焦油馏分为溶剂,在最优操作条件下萃取神府煤,将萃取混合液在510℃条件下热解,分析了热解液体产物的性质及组成,得到了加工方案。结果表明:液体产物主要由酚类化合物、芳烃化合物及烷烃组成,酚类含量较高,其在萃取热解液体产物中的比例均达到50%以上,主要由苯酚、C1～C4苯酚组成,大于C4苯酚的含量很小,其中由苯酚、C1-苯酚、C2-苯酚组成的低级酚含量占总酚含量的70%以上,因此对液体产物进行加工时,需要将低级酚类化合物从液体产物中先分离出来。     

采用超临界技术制备高性能生物滤料的实验研究

采用超临界CO2萃取技术制备高性能的核桃壳滤料,考察了萃取温度、压力及时间对萃取效果的影响。实验结果表明,在萃取温度为45℃,萃取压力为35 MPa,萃取时间为2 h条件下,制备出的核桃壳滤料明显优于常规滤料,平均孔径2.62×10-7cm,比表面积高达9.30 m2/g,总孔容积6.1×10-3cm3/g,约为常规滤料的4倍。大大延长了滤料的运行周期和使用寿命,减少滤料的反冲洗次数,具有很好的节水和处理水的性能。实现了核桃壳的再生利用,达到了以废治废的目的,具有较高的经济效益和社会效益。     

Glycerol in subcritical and supercritical solvents

Glycerol conversion to added value chemicals is a research avenue that has attracted significant interest in recent years. The utilization of critical solvents such as water and organic solvents in critical conditions as well as subcritical conditions (or hot compressed solvent) and supercritical conditions can offer several advantages to batch processes and in continuous flow systems in view of their potential implementation in industry. This review has been aimed to highlight most recent key processes for glycerol valorization to valuable products using different types of catalysts and processes. © 2016 Society of Chemical Industry     

现代食品工业中的超临界流体萃取技术

因为食物中的营养成分具有不稳定性和易被破坏的性质 ,故在其分离和富集过程中需要一些特殊的分离手段。介绍一种适宜在食品工业中应用的新型分离手段——超临界流体萃取     

加压或超临界溶剂对乙醇发酵和在线萃取分离的影响

压缩或超临界流体作为良好的萃取溶剂,在食品加工与保藏、制药和生物材料加工等领域有广阔的应用前景。在简要论述了压缩或超临界流体对微生物存活与催化活性影响的基础上,详细综述了近年来采用超临界溶剂进行乙醇发酵与在线萃取分离过程取得的新进展,特别是装置结构设计和过程优化方面的新成果。最后探讨了实现过程规模化需要深入开展的关键性问题。     

Recovery of triglycerides from used frying oil by extraction with liquid and supercritical ethane

The extraction of triglycerides from used frying oil with liquid and supercritical ethane has been studied in a semibatch system at different temperatures (25-80 °C) and pressures (150-250 kg/cm²). It has been found that isobaric decreases of temperature and isothermal increases of pressure lead to both increasing extraction yields and decreasing separation efficiencies. Lipid fractions recovered in the high density region had acceptable concentrations of polar compounds.Results with ethane have been compared to those reported for CO₂ in earlier works. At similar reduced densities of the solvents, oil solubility in ethane was higher than in CO₂, being the separation efficiency of polar fractions slightly better when using ethane.The extraction process was further analyzed in a packed countercurrent column. At optimum conditions (250 kg/cm², 25 °C, and solvent-to-oil ratio 45 g:g) about 85% of the triglycerides were recovered, being 11.2% the polar content of the triglyceride fraction recovered.     

Extraction of Avgamasya asphaltite with sub- and supercritical solvents

The yields and the nature of the products from the solvent extraction of Avgamasya asphaltite of SE Turkey with benzene and toluene under Soxhlet, subcritical (up to 292 °C) and supercritical (350–450 °C) conditions are reported. The subcritical yield increases with temperature but also depends on pressure; the extra yield is mainly of asphaltenes. The 350 °C supercritical toluene extract shows little evidence of thermal degradation and is similar in yield and chemical nature to that obtained under subcritical conditions except that it contains more pentane-soluble material. At 450 °C the yield is increased and a number of pyrolytic effects are observed, including reduction in molecular mass, loss of heterocyclic and alkyl groups and the presence of toluene decomposition products.     

Hexane and heptane as extraction solvents for cottonseed: A laboratory-scale study

For many years, commercial-grade hexane has been the preferred solvent for extracting oil from cottonseed. Recent environmental and health concerns about hexane may limit the use of this solvent; therefore, the need for a replacement solvent has become an important issue. Heptane is similar to hexane, but does not have the environmental and health concerns associated with the latter. On a laboratory scale, delinted, dehulled, ground cottonseed was extracted with hexane and heptane. The solvent-to-meal ratio was 10:1 (vol/wt). The yield and quality of the oil and meal extracted by heptane were similar to that extracted by hexane. Extraction temperature was higher for heptane than for hexane. A higher temperature and a longer time were required to desolventize miscella from the heptane extraction than from the hexane extraction. Based on these studies, heptane offers a potential alternative to hexane for extracting oil from cottonseed.     

超临界汽油中煤焦油加氢裂化催化剂研究

为了提高超临界汽油中煤焦油加氢裂化轻质油的收率,研究了Co-Mo-Pd-Y沸石催化剂制备条件对轻质油收率的影响。分别考察了催化剂负载金属中Co/(Co+Mo)原子比、催化剂焙烧温度、分子筛酸处理浓度、酸处理温度及时间对煤焦油加氢裂化催化反应收率的影响。结果表明:当Co/(Co+Mo)原子比(摩尔比)为0.5,催化剂焙烧温度为550℃,分子筛酸处理浓度为2 mol/L,酸处理温度为70℃及处理时间4 h时,轻质油收率(质量分数)可达81.5%,并且对此条件下制备的催化剂通过N2吸附及XRD进行了表征。制得的催化剂在超临界溶剂中煤焦油加氢裂化反应中表现出较高的活性,煤焦油获得了高的轻质油收率。     

Recovery of grape seed oil by liquid and supercritical carbon dioxide extraction: a comparison with conventional solvent extraction

In this work the extraction of grape seed oil by means of liquid and supercritical carbon dioxide as solvent is described. The operating conditions to determine the maximum extraction yield were studied. The efficiency of supercritical fluid extraction (SFE) was similar to that obtained by conventional liquid extraction, but the quality of the supercritically extracted oil was higher, equivalent to a degummed, liquid- extracted oil. It is considered that SFE is competitive with conventional liquid extraction, because the solvent distillation and oil refining stages can be omitted.     

New method for the direct analysis of supercritical fluid coal extraction and liquefaction

A new method is described for the direct mass spectrometric analysis of the products of coal supercritical fluid extraction processes. Coal placed in an extraction cell was elevated to supercritical conditions with pressure regulation by a high pressure pump. The extracted products were continuously analysed by direct fluid injection into a mass spectrometer chemical ionization ion source. The extraction process was observed as a function of pressure to determine threshold pressures for individual solutes or as a function of temperature at constant pressure. The method was demonstrated for a supercritical fluid extraction of a bituminous coal by a mixture of n-pentane and 2-propanol at 280 °C and 0.5–10 MPa.     

溶剂与溶胀促进剂对神华煤溶胀行为的影响

采用体积法研究了甲苯、四氢萘、甲醇、二甲亚砜、N,N-二甲基甲酰胺(DMF)和乙醇胺(MEA)5种纯溶剂及1∶1的MEA-DMF混合溶剂对神华烟煤的溶胀行为,考察了Fe(NO3)3、Fe2(SO4)3和FeSO4添加量为0.5%(以铁占煤质量计)作为溶胀促进剂的性能。结果表明:MEA-DMF混合溶剂的溶胀效果优于5种单一溶剂。铁盐Fe(NO3)3明显促进煤溶胀,在80℃,24h和剂煤比5∶1条件下MEA-DMF混合溶剂与Fe(NO3)3协同可使溶胀率超过3.0。对溶胀处理后的神华煤FT-IR表明DMF、DMF-MEA溶胀处理以及与Fe(NO3)3协同溶胀处理后明显削弱了煤羟基氢键间的缔合作用,其中,经DMF-MEA与Fe(NO3)3协同溶胀处理的这一变化最为明显。     

厚壁橡胶制品非等温硫化过程模拟与实验研究

橡胶的硫化反应过程对制品的最终性能起决定性作用,而厚壁橡胶的硫化是典型的非等温硫化过程,通常难以通过实验测得的等温硫化曲线来直接确定制品的最佳硫化工艺。因此,利用数值模拟技术来研究硫化过程对于橡胶的成型加工具有重要意义。鉴于此,基于传统硫化动力学模型,通过引入初始硫化参数并将反应级数视为温度的二次函数,构建了精度更高的改进硫化模型,同时将橡胶热物性参数视为硫化度和温度的函数,基于C语言和FLUENT预定义宏编写了UDF子程序,实现了橡胶制品硫化过程传热与硫化的耦合模拟。针对典型厚壁橡胶制品的平板硫化成型,通过测温实验和不同硫化程度制品拉伸、DSC测试与断面形貌观测,验证了耦合算法对温度场和硫化度模拟的可靠性。该方法对指导厚壁且结构复杂橡胶制品硫化成型更具实际意义。