Purification of Crude Glycerol from Waste Cooking Oil Based Biodiesel Production by Orthogonal Test Method

Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.

Syngas Production from Crude Glycerol Using Pyrolysis

Glycerol pyrolysis is carried out in a fixed bed reactor filled with alumina oxide. The packing material diameter was examined according to each one, but in general it was varied between 0.1-5.0 mm. The reaction temperature was varied in the range of 700-900 ℃, the reaction time from 10 to 50 min and flow rate of carrier gas from 0 to 60 mL/min. The process parameters listed above （factors） were used to evaluate the syngas production yield （response）. Also, syngas properties such as composition and heat value were evaluated. The experiments were carried out according to a 23 factorial design plus three central points. At last, a technical-economical analysis is carried out to examine the feasibility of syngas production from glycerol pyrolysis considering not only feedstock, catalyst and energy required costs but also conventional procedures used nowadays to produce syngas such as water electrolysis and natural gas catalytic reform.

Heterogeneous numerical modelling for the auto thermal reforming of crude glycerol in a fixed bed reactor

A mathematical model for the catalytic autothermal reforming(ATR)reaction of synthetic crude glycerol to hydrogen in a fixed bed tubular reactor(FBTR)and over an in-house developed metal oxide catalyst is presented in this work.The heterogeneous model equations account for a two-phase system of solid catalyst and bulk feed gas.Also,the ATR of crude glycerol reaction scheme and intrinsic kinetic rate model over an active,selective,and stable nickel-based catalyst were integrated in the developed model.Also,the model was validated using experimental data generated in our labs for the ATR of synthetic crude glycerol.The modelling results adequately described the detailed gas product composition and distribution,temperature profiles,and conversion propagation in the axial direction of the fixed bed reactor over a wide range of reaction temperature(773–923 K)and mass-time(12.71–158.23 g cat·min·(mol C)^(-1)).The crude glycerol conversion predicted with the model showing a close resemblance to those obtained experimentally with an average absolute deviation(AAD)of less than 8%.The maximum crude glycerol conversion and hydrogen yield were found to be 92%and 3 mol hydrogen/mol crude glycerol,respectively.Also,the gas product concentration profile in the reactor was adequately described(90%)accuracy with a hydrogen concentration of 39%(volume).

Utilization of Crude Glycerol by Yarrowia lipolytica IMUFRJ 50678 in Bioproduct Production

Transesterification is the most common production process for biodiesel. From this reaction, a glycerin phase is produced that is impure, thus lowering market value. However, because it is rich in carbon, it is an alternative for generating bioproducts with a higher added value through bioconversion by microorganisms. The aim of this study was to screen parameters, such as pH （4, 5, 6, 7 and 8） and the initial glycerol concentration at 30 ± ℃ with agitation at 150 rpm for bioemulsifier and lipid synthesis in a submerged medium by Yarrowia lipolytica IMUFRJ 50678 from crude glycerin. The best conditions for bioemulsifier production were 30 ± ℃ at pH： 6 with 50 g/L of initial substrate, which produced 2.7 g/L of lipids, from which the optimum 300.5 mg/L of triglycerides was produced over 48 h of microorganism growth.

Coal fly ash reinforcement for the property enhancement of crude glycerol-based polyurethane foam composites

Coal fly ash(CFA)is the main combustion residue of fine ground coal in the process of coal-fired thermal power generation,and crude glycerol(CG)is the byproduct of biodiesel production.The novel polyurethane/CFA(PU/CFA)foam composites were prepared from CFA and CG.Two kinds of CFA,CFAI and CFAII were used as fillers for the property enhancement of PU/CFA composites,and the effects on foaming behavior and the reinforcement for the PU/CFA composites were investigated.It was found that the addition of CFA can prolong the rising time and tack-free time,and the maximum rising time and tack-free time increased to 40 s and 42 s.Meanwhile,the maximum compressive strength of PU/CFAI and PU/CFAII increased to 0.2186 MPa and 0.2284 MPa with the addition of CFA.The thermogravimetric analysis showed that the PU/CFA composites underwent three stages of thermal decomposition,and the amount of carbon residue increased from 23.11%to 67.91%with increasing CFA dosage.Moreover,the values of the limit oxygen index increased from 21.5%to 23.7%with the incorporation of CFA into the PU foam matrix,indicating that CFA improved the thermal stability and flame retardant performance of the composites.This study provided a new method for the recycling and high-value utilization of CG and CFA.

Comparative study on production and characterisation of extracellular polymeric substances(EPS)using activated sludge fortified with crude glycerol from different biodiesel companies

Extracellular polymeric substances(EPS)are eco-friendly and economical biopolymers with a significant role in pollutant removal,bio-flocculation,settling and dewatering of activated sludge.In this study,growth profile and EPS production by an EPS-producing microbial strain(isolated from wastewater sludge or WWS)was studied using activated sludge fortified with glycerol.The study compared three crude glycerol samples as carbon sources from different biodiesel companies(BIO-LIQ,BIOCARDEL,ROTHSAY)and their effect on EPS production and characterisation was observed.The maximum slime EPS(S-EPS)concentration(12.34 g/L)was produced when sludge fortified with BIO-LIQ crude glycerol was used,higher than pure glycerol(10 g/L)at 72 h.The S-EPS was enhanced(16 g/L)when purified BIO-LIQ glycerol(by acid treatment)was used.It was also observed that S-EPS concentration increased 1.6-2.6 times by using sludge fortified with glycerol as compared to only glycerol(no sludge)as EPS production medium.In addition,the S-EPS produced from different glycerol samples yielded different characteristics in terms of protein-carbohydrate content,flocculation activity and dewaterability.The S-EPS from purified BIO-LIQ glycerol(with sludge)gave maximum flocculation activity and dewaterability i.e.93.71%and 60.2%respectively.The comparison between Ca(OH)2 and NaOH used as alkaline sludge pre-treatment methods revealed that the EPS produced from Ca(OH)_(2)-treated sludge fortified with glycerol solutions to be better in terms of protein content,flocculation activity and dewaterability.Structural composition analysis using Fourier Transform Infrared Spectroscopy(FT-IR)revealed the presence of distinct functional groups(carboxyl,hydroxyl,amine groups)in the produced S-EPS.

糠醛渣增强粗甘油基聚氨酯泡沫性能的研究

采用一锅法将生物柴油副产物粗甘油(CG)转化为生物基多元醇(CG-polyol),并以糠醛渣(FR)为增强填料,共混发泡制备出一种FR增强生物基聚氨酯(PU/FR)泡沫复合材料。通过对PU/FR泡沫的结构形貌、热稳定性、发泡时间、密度和压缩强度进行表征,探究了糠醛渣粒径(0.25 mm、 0.09 mm样品分别标记为FR60和FR180)和添加量对PU/FR泡沫性能的影响。结果表明:通过热转化法合成的CG-polyol酸值为1.9 mg/g、羟值为406 mg/g、黏度为1 092 mPa·s,该多元醇适合用于制备PU泡沫。FR的加入延长了发泡时间,最大上升时间和不粘时间分别由未添加时的29和31 s提高到37和39 s,泡孔结构更加完整,泡孔尺寸减少,破碎现象明显减少。FR添加量≤5%时,可有效提高泡沫的密度和压缩强度;当添加量相同时,FR180填料对泡沫的性能提升更显著;当FR180添加量为5%时制备的PU/FR180-5泡沫复合材料的压缩强度达到最大为0.153 3 MPa,相比未添加FR的泡沫提高了28.1%,此时密度为0.051 0 g/cm~3,导热系数为0.032 8 W/(m·K),复合材料的综合性能较好。同时FR的添加可适当提高PU泡沫材料的热稳定性,相比未添加FR的泡沫的最大热解速率温度(T_(max))453℃,PU/FR180-5泡沫的T_(max)达到463℃。

Experimental Design as a Tool for the Development of Citric Acid Production by Yarrowia lipolytica Using Glycerol as a Feedstock

Due to the scarcity of fossil fuels in the world, there is increasing interest in the commercial production of biodiesel, which leads to obtaining large amounts of glycerol as a byproduct. If not disposed of properly, glycerol can generate environmental impact. One of the promises, the application of the crude glycerol is the production of citric acid by microbial fermentation. Citric acid is industrially produced by a submerged fermentation process with Aspergillus niger, using sucrose as carbon source, but due to increased demand for citric acid, alternative processes using renewable sources or waste materials as substrates and the cultivation of yeast strains are being studied. The aim of the study was to determine the best culture condition for maximum citric acid synthesis and lower isocitric acid production from crude glycerol through experimental design tool. For this purpose, the yeast strain Yarrowia lipolytica IMUFRJ-50682 was cultivated in nitrogen-limited glycerol-based media. Therefore, glycerol and yeast extract concentrations and agitation speed were evaluated as independent variables. With pure glycerol, the highest citric acid production achieved was 16.5 g/L with an isocitric acid production of 7.7% （in relation to citric acid）. With crude glycerol, citric acid production reduced to 6.7 g/L because of higher biomass yield. Therefore, an increase in the initial carbon to nitrogen molar ratio from 714 to 1,561 was necessary to increase citric acid production to 9.2 g/L, reducing isocitric acid production and to achieve a yield of 0.41 g of citric acid per glycerol consumed. In this condition, less nitrogen source was used, reducing production costs.

生物柴油副产物粗甘油的综合利用

生物柴油作为一种可替代化石燃料的可再生能源,得到了快速发展和规模化生产,使得其副产物甘油的产量过剩。通过简单工艺过程处理生物柴油,即可得到粗甘油,而粗甘油中除甘油外,还有其他的杂质组分,要想将其应用于食品、化妆品及医药等行业就必须对粗甘油进行精制。而当前,粗甘油精制工艺路线较为繁琐,成本较高,经济可行性比较低,故需开发粗甘油的应用空间,提高粗甘油的附加值。本文从生物柴油副产物粗甘油的综合应用入手,从生产化工产品,如1,2-丙二醇、1,3-丙二醇、DHA、PHA、丙烯醛等,用于制氢,用于制燃料添加剂,用于燃料电池,制甲醇或乙醇以及废物处理等领域概述了当前粗甘油的应用技术工艺现状。通过不断拓展粗甘油的应用前景,为生物柴油技术工艺的可持续发展提供技术支撑。

竹废料液化制备多羟基化合物研究

在硫酸的催化作用下,竹废料在由聚醚多元醇和粗甘油组成的混合液化剂中可被液化成多羟基化合物。重点研究了液化温度、液化时间、催化剂用量、竹屑添加量等液化反应参数对竹废料液化反应的影响。研究结果表明,当液化温度为160℃、液化时间为120 min、催化剂用量为液化剂质量的3%、竹屑量占液化剂质量的30%时,液化率可达95%,所得液化产物的羟值205 mg(KOH)/g,黏度为890 mPa.s,可以用于半硬质聚氨酯泡沫的制造。同时通过红外光谱分析方法对竹屑液化的机理做了初步探讨。

文冠果油生物柴油副产物粗甘油的精制

文冠果油生物柴油副产物粗甘油中不仅含有甘油,还含有皂类、水分、甲醇和酯类物质等,其甘油含量在30%～60%。通过皂化、酸化、极性试剂萃取和活性炭吸附的方法对文冠果油生物柴油副产物粗甘油进行连续精制。结果表明,粗甘油经氢氧化钾甲醇溶液皂化,再用H3PO4调pH至2.5酸化,甲醇和粗甘油体积比为4∶1萃取,100 g/L活性炭吸附脱色处理后,可以得到纯度为98.5%的精制甘油。

气相色谱法测定粗甘油中的游离甘油含量

建立了气相色谱法直接测定生物柴油副产物粗甘油中甘油含量的方法。采用四氢呋喃-水(3∶1)混合溶剂溶解粗甘油样品,以二乙二醇二乙醚作内标,直接在HP-5柱上进行GC法分离,无需衍生化步骤,内标法定量。对溶剂、内标物、色谱柱、进样量等参数进行了优化,在最佳实验条件下,甘油溶液质量浓度在0～20 g/L范围内线性良好,相关系数为0.999 94。对实际样品进行8次平行测定,相对标准偏差为0.68%～0.91%。对样品进行高、中、低3个水平的加标回收实验,回收率在95%～105%之间。该方法所选用的溶剂和内标物均不会和体系中的物质发生化学反应,操作简便、分析快速、结果准确,适用于粗甘油中游离甘油的测定。

生物柴油副产物甘油发酵生产1,3-丙二醇的研究

对利用不同生物柴油副产物粗甘油发酵生产1,3-丙二醇的试验条件进行了研究。批次发酵试验结果表明:精制甘油(纯度>98%)、生物柴油副产物粗甘油A(纯度83%)和B(纯度78%)及C(纯度68%)生成1,3-丙二醇的转化率分别为52.38%、48.08%、45.22%、39.95%;精制甘油、粗甘油A和B及C的流加补料发酵合成1,3-丙二醇的转化率分别为51.45%、44.63%、41.27%、35.39%。经济效益粗略评估分析表明,生物柴油副产物粗甘油A和B生产单位1,3-丙二醇较精制甘油成本低,生物柴油副产物粗甘油C却较精制甘油成本高。

生物柴油副产物制备高纯度甘油的研究

通过建立一套简单、有效的测量生物柴油下层副产物组成的方法,并用此方法对菜籽毛油制生物柴油下层副产物中各成份进行了定量分析,结果显示生物柴油下层副产物中含有43.73%的甘油,21.73%的脂肪酸皂,14.23%的生物柴油,16.47%的甲醇和少量其它杂质。通过用硫酸的甲醇溶液酸化脱盐的预处理方法,考察了甲醇用量、溶液pH值对脱盐率、粗甘油的纯度及收率的影响,结果显示甲醇用量为下层副产物的0.5倍体积,溶液pH值为5时,可得到纯度为90%的甘油粗产品,脱盐率可达到90%,甘油的收率也在95%以上。在此基础上,用减压蒸馏和离子交换两种方法对粗甘油进行了精制。这两种方法均可得到纯度高于99.5%的精制甘油,但离子交换精制工艺的甘油总收率可达到85%以上,而减压蒸馏精制工艺的甘油总收率仅为70%。

铜绿假单胞菌分泌鼠李糖脂能力对原油降解影响的研究

研究了铜绿假单胞菌分泌鼠李糖脂能力对原油生物降解的作用。将保存在原油中的铜绿假单胞菌转接至甘油培养基进行继代培养,观察到各继代培养下鼠李糖脂分泌量越高则该发酵液对原油的乳化降解能力就越强,推测该菌产鼠李糖脂能力决定了该培养液对原油的乳化与降解程度。鉴于此,分别将鼠李糖脂提取液、发酵液加入到原油培养基中,观察其各自的原油乳化程度的变化趋势,发现鼠李糖脂本身可以乳化原油但不能降解原油,且其乳化能力不如去菌体的发酵液。去菌体发酵液能很快地乳化原油而同样不能降解原油。只有含菌体的发酵液既能乳化又能降解原油。因此,可以认为鼠李糖脂本身具有乳化原油的能力,但是由铜绿假单胞菌同时分泌的其它表面活性物质可能协同鼠李糖脂更好地乳化原油以促进微生物对原油的利用与降解。

响应面试验优化产琥珀酸放线杆菌GXAS137发酵粗甘油产丁二酸工艺

通过优化产琥珀酸放线杆菌GXAS137发酵粗甘油产丁二酸的培养基,提高丁二酸产量,降低生产成本。先通过单因素试验对粗甘油发酵产丁二酸的电子受体、初始粗甘油质量浓度及氮源进行了优化,再利用响应面试验确定重要参数的最佳水平。结果表明:二甲基亚砜(dimethyl sulfoxide,DMSO)为最适电子受体,玉米浆可替换酵母粉作为氮源,各因素的最佳条件为:初始粗甘油质量浓度55.43 g/L、DMSO质量浓度10.35 g/L、玉米浆质量浓度17.69 g/L。优化后丁二酸产量达到37.02 g/L,丁二酸得率为66.79%,生产强度为0.51 g/(L·h)。与初始条件下丁二酸产量(16.88 g/L)相比,优化后提高了1.19倍。本研究为微生物发酵粗甘油原料生产丁二酸提供了理论支持。

微生物发酵粗甘油生成1,3-丙二醇的研究进展

粗甘油是生物柴油生产中的一个主要副产物,而通过微生物可将粗甘油转化为高附加值的1,3-丙二醇。1,3-丙二醇在食品、化工、医药、化妆品等很多领域具有非常广泛的应用。本文从1,3-丙二醇的粗甘油生物转化的迫切性、生产的菌种、合成的途径、合成的基因、发酵转化以及生产中的问题与策略等方面综述了微生物发酵粗甘油生成1,3-丙二醇的最新研究进展。

超声波在高酸原油酯化脱酸中的应用研究

将超声波技术应用到高酸原油酯化反应脱酸中。以甘油为酯化脱酸剂,研究醇酸摩尔比、反应温度、反应时间、超声功率对多巴高酸原油自催化酯化反应脱酸的影响,并与磁力搅拌作用下的脱酸效果进行对比。结果表明,在醇酸摩尔比为6、反应温度为250℃、反应时间为30min、超声功率为90W的条件下,多巴原油酸值可由4.74mgKOH/g降到0.21mgKOH/g,脱酸率高达95.6%。在反应温度为220℃的条件下,超声处理的脱酸效果优于磁力搅拌,超声处理后的油样性质变化不大。

菜籽油生物柴油水洗去除游离甘油的工艺参数研究

甘油是生物柴油生产过程中的主要副产物。生物柴油中甘油含量多少是评价生物柴油质量好坏的重要指标之一。通过水洗可以很容易去除粗生物柴油中的游离甘油,但是水洗不仅会产生大量工业废水,而且增加产品成本。为此,以菜籽油为原料,介绍了菜籽油制备生物柴油及水洗生物柴油的工艺方法,考察了水洗次数、水洗温度、水洗质量分数对粗生物柴油中游离甘油去除率的影响。通过单因素实验得出去除粗生物柴油中游离甘油的最佳工艺条件为:水洗至少5次,水洗温度40℃,水洗质量分数20%,为生物柴油工业化生产提供了参考依据。

生物质副产物粗甘油制备丙烯酸

以粗甘油为原料,采用新型负载型杂多酸催化剂和氧化物催化剂,通过两段反应制备丙烯酸。利用BET、NH_3-TPD、FTIR和原子吸收光谱分析等方法分析了粗甘油中不同杂质的影响。实验结果表明,粗甘油中的无机盐离子是造成粗甘油脱水产物丙烯酸收率降低、乙酸收率增加的主要原因。Na^+和K^+等碱金属杂质沉积在HPW/Cs-SBA催化剂表面,导致催化剂的比表面积和孔体积显著降低,平均孔径增大,催化剂上大量的中强酸性位点转化成弱酸性位点,酸性位点的总量也有所下降。只需对粗甘油进行脱盐处理,而不需要脱除其他有机物杂质即可用于脱水制备丙烯酸,反应70 h内丙烯酸收率稳定在86%左右,与使用精制甘油时的效果相当。