Optimization and simultaneous heat integration design of a coal-based ethylene glycol refining process by a parallel differential evolution algorithm

Coal to ethylene glycol still lacks algorithm optimization achievements for distillation sequencing due to high-dimension and strong nonconvexity characteristics,although there are numerous reports on horizontal comparisons and process revamping.This scenario triggers the navigation in this paper into the simultaneous optimization of parameters and heat integration of the coal to ethylene glycol distillation scheme and double-effect superstructure by the self-adapting dynamic differential evolution algorithm.To mitigate the influence of the strong nonconvexity,a redistribution strategy is adopted that forcibly expands the population search domain by exerting external influence and then shrinks it again to judge the global optimal solution.After two redistributive operations under the parallel framework,the total annual cost and CO_(2) emissions are 0.61%/1.85%better for the optimized process and 3.74%/14.84%better for the superstructure than the sequential optimization.However,the thermodynamic efficiency of sequential optimization is 11.63%and 10.34%higher than that of simultaneous optimization.This study discloses the unexpected great energy-saving potential for the coal to ethylene glycol process that has long been unknown,as well as the strong ability of the self-adapting dynamic differential evolution algorithm to optimize processes described by the high-dimensional mathematical model.

Reaction pathways and selectivity in the chemo-catalytic conversion of cellulose and its derivatives to ethylene glycol:A review

Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.

Analysis of Ethylene Glycol Degumming Process and Characterization of Hemp Fibers

To overcome the shortcomings of traditional degumming process,an efficient and environmentally friendly ethylene glycol(EG) degumming process was adopted to degum hemp fibers.The surface morphology,chemical composition,chemical structures,and mechanical properties of the fiber samples were analyzed to explore the mechanism of the degumming process.It was found that the EG degumming process could be divided into the main degumming stage(heating) and the supplementary degumming stage(insulation).The removal rates of hemicellulose and lignin in the main degumming stage were 70.56% and 60.17%,respectively.In the supplementary degumming stage,9.95% hemicellulose and 25.39% lignin were removed.It is confirmed that EG can separate hemp fibers effectively with less damage,which holds great potential for the biomass fiber separation technology.

Study of Thermal,Phase Morphological and Mechanical Properties of Poly(L-lactide)-b-Poly(ethylene glycol)-b-Poly(L-lactide)/Poly(ethylene glycol)Blend Bioplastics

A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.

Preparation and Thermo-Responsive Properties of Poly(Oligo(Ethylene Glycol)Methacrylate)Copolymers with Hydroxy-Terminated Side Chain

Thermo-responsive random copolymers,poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-(ethylene glycol)methyl ether methacrylate)(P(EO_(2)-co-EO_(4/5)))and poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylene glycol methacrylate(P(EO2-co-EG4/5))are synthesized via atom transfer radical polymerization(ATRP).The successful synthesis and the narrow polydispersity index(PDI)of two copolymers are indicated by 1H nuclear magnetic resonance(1H-NMR)and gel permeation chromatography(GPC)analyses.The transition behaviors of polymers in the aqueous solution are demonstrated by changes in turbidity and particle sizes.The transition behavior of P(EO2-co-EG4/5)is found to be milder than that of P(EO2-co-EO4/5).Moreover,the presence of hydrogen bonds without thermo-responsive properties established by hydroxyl groups in the end-side chain of P(EO_(2)-co-EG_(4/5))hinders the dehydration at the transition temperature(TT).Attenuated total reflection Fourier transform infrared spectrometry(ATR-FTIR)analysis along with contact angle measurements reveals that both P(EO_(2)-co-EO_(4/5))and P(EO_(2)-co-EG_(4/5))films undergo phase transitions from hydrophilicity to hydrophobicity above TT.By examining the swelling and collapse behaviors of the polymer films during phase transitions,it can be concluded that the end hydroxyl groups may establish hydrogen bonds with neighboring ether groups within the films,which remain intact throughout the phase transition process due to their strong bonding interactions.This leads to an increase in steric hindrance within swollen films thereby impeding dehydration processes and inducing hysteresis during phase transitions.

Significance of Nanoparticles Aggregation with Cattaneo-Christov Heat Flux on the Water and Ethylene Glycol Mixture Based MWCNTs-Nanofluid Flow over a Stretching Cylinder

This work aims to analyze the flow of electrically conducting MWCNTs-nanofluid over a stretching cylinder with the aggregation and non-aggregation effects of nanoparticles. The working fluid comprised a combination of water and ethylene glycol, with volumetric proportions of (50:50) considered. Convective boundary constraints and modified Fourier law are implemented in heat transmission assessment. The mathematical flow model is formulated in the form of PDEs and is transformed into ODEs via similarity transformation. Numerical outcomes will be obtained with the use of the bvp4c technique and will be displayed with the help of graphs and tables. The results show that the surface drag coefficient is enhanced in the case of aggregation of nanoparticles whereas heat transfer rate is enhanced in the non-aggregation effect of nanoparticles. Furthermore, the temperature distribution enhances the increasing values of particle volume fraction in the case of aggregation effects of nanoparticles whereas temperature distribution lowers in the case of non-aggregation effect of nanoparticles. .

Cu_2[ethyleneglycolbis(2-aminoethy)tetraacetate·2H_2O]·2H_2O:双核铜配合物的合成和晶体结构

乙二醇双(2-氨乙基醚)四乙酸(ethylene glycol bis(2-amino ethy)tetraacetate:EGTA)和氯化铜采用溶液蒸发方法在甲醇和水的混合溶液中成功合成双核铜配合物Cu2[EGTA.2H2O].2H2O。该晶体的结构数据是在单晶衍射仪进行收集的。通过晶体结构分析,该晶体属单斜晶系,空间群为C2/c,晶胞参数如下:a=21.013(4),b=7.5503(1),c=13.577(2),β=90.877(2)°,V=2153.8(6)3。在化合物中,铜离子分别与配体的三个氧原子和一个氮原子以及一个水分子成键,采取五配位四面体构型,铜离子空间构型是畸变的四方锥。另外,游离的水分子与配体的氧原子形成氢键而构筑成超分子。

Synthesis of Nano-sized Yttria via a Sol-Gel Process Based on Hydrated Yttrium Nitrate and Ethylene Glycol and Its Catalytic Performance for Thermal Decomposition of NH_4ClO_4

Nano-sized yttria particles were synthesized via a non-aqueous sol-gel process based on hydrated yttrium nitrate and ethylene glycol. The effects of the molar ratio of ethylene glycol to yttrium ion and calcination temperature on crystallite size of the products were studied. The catalytic performance of the as-prepared yttria for the ammonium perchlorate （AP） decomposition was investigated by differential scanning calorimetry （DSC）. The results indicate that the nano-sized cubic yttria particles with less than 20 nm in average crystallite size can be obtained after 2 h reflux at 70℃, dried at 90 ℃, forming xerogel, and followed by annealing of xerogel for 2 h, and that the addition of the nano-sized yttria to AP incorporates two small exothermic peaks of AP in the temperature ranges of 310 - 350 ℃ and 400 - 470 ℃ into a strong exothermic peak of AP and increases the apparent decomposition heat from 515 to over 1110 J·g^- 1. It is also clear that the temperature of AP decomposition exothermic peak decreases and the apparent decomposition heat of AP increases with the increase of the amount of nano-sized yttria. The fact that the addition of the 5 % nano-sized yttria to AP decreases the temperature of AP exothermic peak to 337.7℃ by reduction of 114.6℃ and increases the apparent decomposition heat from 515 to 1240 J·g^-1, reveals that nano-sized yttria shows strong catalytic property for AP thermal decomposition.

Effect of copper loading on texture,structure and catalytic performance of Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

Cu/SiO2 catalysts prepared by a convenient and efficient method using the urea hydrolysis deposition-precipitation （UHDP） technique have been proposed focusing on the effect of copper loading.The texture,structure and composition are systematically characterized by ICP,FTIR,N 2-physisorption,N2O chemisorption,TPR,XRD and XPS.The formation of copper phyllosilicate is observed in Cu/SiO2 catalyst by adopting UHDP method,and the amount of copper phyllosilicate is related to copper loading.It is found the structure properties and catalytic performance is profoundly affected by the amount of copper phyllosilicate.The excellent catalytic activity is attributed to the synergetic effect between Cu0 and Cu ＋.DMO conversion and EG selectivity are determined by the amount of Cu0 and Cu＋,respectively.The proper copper loading （30 wt%） provides with the highest ratio of Cu ＋ /Cu0,giving rise to the highest EG yield of 95% under the reaction conditions of p=2.0 MPa,T=473 K,H2/DMO=80 and LHSV=1.0h-1.

Selective swelling of polysulfone/poly(ethylene glycol) block copolymer towards fouling-resistant ultrafiltration membranes

Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.

Effects of cupric ions on the corrosion behavior of aluminum alloy 5A02 in ethylene glycol–water solution

The effects of cupric ions on the corrosion behavior of aluminum alloy 5A02 in ethylene glycol–water solutions were studied by potentiodynamic polarization,electrochemical noise(EN),and complementary techniques including scanning electron microscopy(SEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS). A positive corrosion potential and increased corrosion current were observed due to the deposition of copper. The results demonstrate that the main corrosion type was pitting and the increasing cupric ion concentration augmented the pitting density. The pits became larger and deeper as a result of the embedment of copper into the surface of the alloy. Cupric ions were preferentially deposited at the defects around the secondary phase,leading to the formation of Al–Cu microgalvanic couples,which increased the corrosion rate. The corrosion rate gradually reached a stable value as the concentration of cupric ions was increased beyond 10 mmol/L.

Controlled delivery of ibuprofen from poly(vinyl alcohol)-poly(ethylene glycol) interpenetrating polymeric network hydrogels

Hydrogels composed of poly(vinyl alcohol)(PVA) and poly(ethylene glycol)(PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprofen(IBF). To regulate the drug delivery, solid inclusion complexes(ICs) of IBF in β–cyclodextrin(β–CD) were prepared and added to the hydrogels. The ICs were prepared by the microwave irradiation method, which is more environmentally benign. The formation of IC was confirmed by various analytical techniques and the synthesized hydrogels were also characterized. Controlled release of drug was achieved from the hydrogels containing the ICs in comparison to the rapid release from hydrogels containing free IBF.The preliminary kinetic analysis emphasized the crucial role of β–CD in the drug release process that influences the polymer relaxation, thereby leading to prolonged release. The cytotoxicity assay validated the hydrogels as non-toxic in nature and hence can be utilized for controlled delivery of IBF.

Interface tuning of Cu+/CuO by zirconia for dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst

An efficient ZrO2-doped Cu/SiO2 catalyst was fabricated through hydrolysis precipitation method(HP)and used to produce ethylene glycol(EG)through dimethyl oxalate(DMO)hydrogenation.The states for zirconia on copper catalyst and roles in DMO hydrogenation were investigated through various characterization tools,including N2 physical adsorption,XRD,H2-TPR,Methyl glycolate-TPD-MS,XPS,XAES as well.Compared with common ammonia evaporation and co-precipitation methods used in catalyst preparation,this HP method is found to effectively suppress the agglomeration and further size growth of copper nanoparticles by enhancing the interactions between copper and zirconia species.More importantly,uniform distribution of ZrO2 dopant is achieved due to the pseudo-homogeneous reactions in the mixing step of catalyst preparation.A proper amount of zirconium dopant helps achieve the desirable proportion of Cu+/(Cu++CuO)for surface copper species,especially promotes the production of Cu+species originated from Cu-ZrO2 species at the interface of copper and zirconia particles.In comparison with Cu+species formed from copper phyllosilicates reduction,the Cu+sites derived from Cu-ZrO2 species show higher adsorption ability of MG,an important intermediate species in ethylene glycol production.These adsorbed MG molecules further react with atomic hydrogen shifted from adjacent metallic copper surface,leading to a higher catalytic behavior.For the EG production via DMO hydrogenation,the turnover frequency(TOF)normalized by CuO species on CuZr/SiO2 catalyst is 1.8 times than that of traditional Cu/SiO2 counterpart.Due to the enhanced synergy effect between Cu+and Cuo active sites,a lower activation energy of ester hydrogenation on this ZrO2-doped Cu/SiO2 catalyst is believed to be responsible for the significant improvement.

SURFACE MODIFICATION OF BLEND FILMS COMPOSED OF SILK FIBROIN AND POLY(ETHYLENE GLYCOL) MACROMER AND THEIR IN VITRO ANTITHROMBOGENICITY

In order to improve the blood compatibility of silk fibroin (SF), poly(ethylene glycol) macromer (PEGM) in different amounts was added to the SF film to incorporate C=C group into the surface of blend films which were then modified by SO2 gas plasma treatment. ATR-FITR and XPS were used to analyze the chemical change which had occurred on the film's surface. When the content of sulfur on the surface of blend films surpasses 1.59%, the antithrombogenicity of plasma treated films increases remarkably due to surface sulfonation. This result implies that SF with blend of PEGM after SO2 plasma treatment have potential use for making blood-contacting biomaterials.

Catalytic Performance and Texture of TEOS Based Cu/SiO_2 Catalysts for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

Highly active and selective Cu/SiO2 catalysts for hydrogenation of dimethyl oxalate（DMO） to ethylene glycol（EG） were successfully prepared by means of a convenient one-pot synthetic method with tetraethoxysi lane（TEOS） as the source of silica. XRD, H2-TPR, SEM, TEM, XRF and N2 physisorption measurements were performed to characterize the texture and structure of Cu/SiO2 catalysts with different copper loadings. The active components were highly dispersed on SiO2 supports. Furthermore, the coexistence of Cu0 and Cu＋ contributed a lot to the excellent performance of Cu-TEOS catalysts. The DMO conversion reached 100% and the EG selectivity reached 95% at 498 K and 2 MPa with a high liquid hourly space velocity over the 27-Cu-TEOS catalyst with an actual cop per loading of 19.0%（mass fraction）.

Optimisation of Bio-polyol Production from Cassava Residue Using Ethylene Glycol as the Liquefaction Reagent

Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.

Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.

THE STRUCTURE AND PROPERTIES OF CHITOSAN/POLYETHYLENE GLYCOL/SILICA TERNARY HYBRID ORGANIC-INORGANIC FILMS

The ternary hybrid films consisting of chitosan(CS),polyethylene glycol(PEG)and nano-sized silica which was surface-modified by amino groups(RNSA)were prepared.The structures of the blend membranes were characterized by attenuation total reflection-infrared spectroscopy(ATR-IR),X-ray diffraction(XRD),optical microscopy(OM)and differential scanning calorimetry(DSC).The results showed that the addition of silica affected not only the distribution and crystallinity of PEG on the sample surface,but also the pha...

Poly(L-lactide)-Poly(ethylene glycol) Multiblock Copolymers: Synthesis and Properties

Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.

PREPARATION OF HIGH DENSITY POLYETHYLENE/POLYETHYLENE-BLOCK-POLY(ETHYLENE GLYCOL)COPOLYMER BLEND POROUS MEMBRANES VIA THERMALLY INDUCED PHASE SEPARATION PROCESS AND THEIR PROPERTIES

High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.