Materials In Petrochemical Industry Research Articles

The study of horizontal extension distances for inclined ethylene buoyant jet fires

As one of the most important raw materials in petrochemical industry, ethylene is widely used in the production of polyethylene, vinyl chloride and so on. Experiments were conducted on inclined ethylene jet fires to study the flame horizontal extension distance. Two nozzles with inner diameters of 6 mm and 10 mm were chosen in current study. Four different upward inclined angles of 0°, 30°, 60°and 90°relative to the horizontal direction were employed. The horizontal extension distances of ethlene jet fires increase with increasing heat release rate. For a fixed heat release rate, the horizontal extension distance decreases when the inclined angles increase. Similarity analysis was accomplished, and the result demonstrates that the dimensionless horizontal extension distance (Lph/d) can be correlated to the flame Froude number (Frf). By fitting the experimental data, the relationship between the dimensionless horizontal extension distance and the modified flame Froude number Frf*(Frf* = cosθ3/4. Frf) was derived, and the correlation can well predict the data in current work as well as these from previous studies. For vertically oriented ethylene jet flame (θ=0°), the normalized flame width (W/d) was exponentially correlated to the flame Froude number by a power of 0.41.

Experimental Investigation of p-Xylene Crystallization Characteristics and Ultrasound Enhancement Mechanism

Para-xylene (PX) is one of the most crucial aromatic raw materials in petrochemical industry. It is urgent to develop a more low-cost and efficient PX production process due to the growing demand for PX. This paper introduces ultrasound into the PX crystallization process and analyzes the data of supersolubility, metastable zone width, and induction period of PX under different working conditions. Based on the classical nucleation theory and the cluster coalescence model, the PX crystallization characteristics and the mechanism of ultrasound enhancement are investigated. The results can be concluded as follows. Ultrasound significantly reduces the metastable zone width and induction period of the PX crystallization process, speeds up the crystal nucleation rate, and prevents the explosion nucleation. When the supersaturation is above 1.055, the PX nucleation mechanism is homogeneous nucleation, and when it is below 1.055, the PX nucleation mechanism is heterogeneous nucleation. The crystal growth mechanism is continuous growth. The PX-dominated cluster at the mesoscale contains 14 monomers. The formation period of clusters is accelerated by ultrasound, and the critical nucleation radius and critical nucleation free energy of PX are both dramatically decreased. The system’s diffusion coefficient is improved by ultrasound, which also lowers the interfacial tension and the surface entropy factor corresponding to the two nucleation mechanisms. When the ultrasonic power changes from 0 to 88 W, the crystal nucleation rate constant increases by 22.4 times and the diffusion coefficient by 11.86 times. Theoretically, this study might enable future PX crystallization process improvements.

Fine-Tuning Pore Dimension in Hybrid Ultramicroporous Materials Boosting Simultaneous Trapping of Trace Alkynes from Alkenes.

Removing trace amounts of alkynes from alkenes is one of the most critical and challenging steps to produce high-purity alkenes, the fundamental raw materials in petrochemical industry. Selective hydrogenation using noble metal catalysts under harsh conditions can convert trace alkynes to alkenes, but suffers from limited selectivity, over-hydrogenation, and energy-intensive consumption. Herein, the simultaneously adsorptive removal of trace propyne (C3 H4 ) and acetylene (C2 H2 ) from quaternary C2 H2 /C2 H4 /C3 H4 /C3 H6 mixture is reported for the first time using an anion-pillared hybrid ultramicroporous material ZU-16-Co (or TIFSIX-3-Co) by finely tuning the pore dimensions and introducing different binding sites to match the shape of alkynes. ZU-16-Co with contracted aperture size and judiciously extended cell dimension simultaneously exhibits superior trapping capacity for propyne under low concentration (2.45mmol g-1 at 5000ppm) and surprisingly high C2 H2 uptake (4.18 and 1.4mmol g-1 at 1.0 and 0.01bar, respectively) through synergistic host-guest and guest-guest interactions. Importantly, the ability of ZU-16-Co to capture trace alkynes (C2 H2 and C3 H4 ) in one step is confirmed by breakthrough experiments for quaternary C3 H4 /C2 H2 /C3 H6 /C2 H4 mixtures, presenting ZU-16-Co as a promising material for alkyne trapping.

Sustainable olefin supply chain network design under seasonal feedstock supplies and uncertain carbon tax rate

The growing environmental consciousness resulted from global climate changes has aroused petrochemical industries to search for the renewable alternatives for fossil fuels. Recently, biomass has been received increasing attention due to its economic and environmental benefits. Olefin, as one of the key raw materials in petrochemical industries, is able to be produced from biomass feedstocks. This study presents a robust three-stage stochastic programming model to characterize and optimize an olefin supply chain/production network aiming to provide a reliable and economic logistics network to support olefin production. This model encompasses probabilistic scenarios and uncertainty sets to capture the seasonality of biomass feedstocks and the uncertainty of carbon tax rate, respectively. The Municipal Solid Waste (MSW) is also involved in this model to complement the traditional biomass supplies to ensure the reliable feedstock for olefin production. To find the optimal solution of this model, a hybrid robust/stochastic approach is developed by integrating the affinely adjustable robust model with the sample average approximation (SAA) method. The state of Mississippi is used as a real case study to test and validate the proposed model and optimization approach. The results show that increasing feedstocks conversion rate by 20% and MSW recycling rate by 100% will increase olefin production by 17.26% and 14.3%, respectively, and increasing the carbon tax rate uncertainty from 0 to 30 will decrease the total network emissions by 2.8%. The proposed optimization approach will generate more robust and reliable results. These results indicate that the proposed model and optimization approach would benefit both economic and environmental perspectives in biomass based olefin production.

Impact of Applied Potential on the Structural and Non-lubricated Wear Composite Coating in Petrochemical Industry

The need to improve the structural properties of materials in petrochemical industry, due to recurring failure, has motivated this study. The effect of deposition potential on structural integrity, surface topography and micromechanical progression of Zn based induced aluminium and TiO2 alloy coating series on mild steel was studied. The wear stability and microhardness behaviour of the developed composite coating was examined via, respectively, sliding reciprocating rig and dura scan diamond based microhardness tester. The structural reliability was inspected with scanning electron microscope equipped with EDS, and atomic force microscope. The results showed that the superb structural crystal resulted into a significant increase in the microhardness, and into a decrease in wear plastic deformation in a non-lubricated system. The precipitation of the deposits enforces stable crystal orientation and compact grains growth. The work has established that up to 13wt% TiO2 on zinc rich bath, a solid composite coating on mild steel, can be used to improve the service life of coating for stable structural properties.

Production of petroleum-like synthetic fuel by hydrocracking of crude soybean oil over ZSM5 zeolite – Improvement of catalyst lifetime by ion exchange

It is possible to produce hydrocarbons by hydrocracking of biomass, such as those produced by crude oil cracking. This product can be incorporated as raw material in petrochemical industry and used as petroleum fractions without any changes on engines. The hydrocracking process was performed over NaZSM5 and HZSM5, where the improvement of this acidity was carried out by ion exchange with ammonia followed by calcination. The reactions were performed on a stainless steel fixed bed reactor. The catalyst was evaluated at 723K and 138kPa, under flow of hydrogen gas, with weight hourly space velocity (WHSV) of 4h−1. Products are analysed by gas chromatography with mass spectra detector (GC–MS) and by nuclear magnetic resonance (NMR) of 1H. For the fresh catalyst, all triglyceride was converted to hydrocarbon by the process. For NaZSM5, the catalyst activity is high but has a high decrease over the time of reaction. It was changed for HZSM5, where the catalyst maintained a high activity even after 90min of reaction. This treatment improved also the product, where a high yield of gaseous hydrocarbon was changed to a high yield of liquid hydrocarbon, especially by the presence of aromatics molecules.

Catalytic oxidative dehydrogenation of 1-butene to 1,3-butadiene using CO2

1,3-Butadiene (BD) is an important raw material in petrochemical industry and its consumption is expected to increase dramatically. Catalytic oxidative dehydrogenation (ODH) of 1-butene is an alternative route to produce BD. In this study, a soft oxidant, CO2 was used instead of O2. Fe2O3 was selected from a preliminary screening using Temperature Programmed Surface Reaction (TPSR). The catalytic performance was greatly improved by supporting Fe2O3 on Al2O3. This contribution clearly shows that both Fe2O3 and CO2 are involved in the reaction. The main byproducts, trans/cis-2-butenes, can also be converted to BD with similar BD yield. A preliminary reaction mechanism is proposed.

Formulation and curing characteristics of EPDM/NR and EPDM/SBR polyblends used in metallic surfaces rubber lining

AbstractIn this work, a new elastomeric liner was introduced to protect the metal surfaces of storage tanks against corroding materials in petrochemical industries. This new liner was prepared on the basis of EPDM/NR and EPDM/SBR compounds. The elastomeric compounds were cured by using super‐heated water vapor at atmospheric pressure. To increase the rate of curing in these rubber samples, the optimum curing system contained 15 phr sulfur and 1.5 phr mercaptobenzothiazole, 1.5 phr zinc diethyl dithiocarbamate, and 1.8 phr tetramethylthiuram disulfide accelerators. Mechanical tests showed that ultimate tensile strength, elongation at break, and hardness of both polyblend samples were comparable to the SBR/NR blend, which is widely used in the rubber lining of metallic surfaces. In the next step, the chemical resistance of the samples was measured by placing them in a 30 wt % HCl solution. The tensile strength, elongation at break, and weight loss of the samples were measured before and after immersion in HCl. Also, the chemical resistances for EPDM/NR, EPDM/SBR, and SBR/NR samples were qualitatively measured in caustic solution. The cracking, blistering, permeability, and adhesion of the rubber samples to steel surface were observed. Finally, the results showed that EPDM/SBR (70/30) polyblend can be a suitable substitute for conventionally used SBR/NR (50/50) for a successful rubber used to line metallic surfaces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Problems of Raw Material in Petrochemical Industry

Japanese chemical industry serves a lot in its technology the electronics and other industries in Japan by providing them with their parts and materials.The che-mical industry plays an essential part in developing such future technologies as the alterna-tive energy, biotechnology, new ceramics and so on.At present, Japanese chemical industry have an unexperienced hard time in securing their main raw materials.Furthermore, Japanese chemical industry which has lost their power in the international competition, faces a mass import of intermediate products from U.S.A.at present and from Canada in the near future.Such being the situation, it is very difficult to estimate for us the volume of raw materials in home consumption even if we are able to estimate the demand of the finished goods.Constant efforts are being made in the research and development of new raw materials to solve the existing problems, but it will not be realized until the21st Century.