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Dry and steam reforming of methane. Comparison and analysis of recently investigated catalytic materials. A short review.

Abstract

In order to produce valuable syngas, industrial processes of dry reforming of methane and steam reforming of methane must be further developed. This paper is focused on reviewing recently examined catalysts, supporting the mentioned technologies. In both processes the most popular active material choice is usually nickel, due to its good availability. On the other hand, noble metals, such as ruthenium, rhodium or platinum, provide better performance, however the solution is not cost-effective. Materials used as a support influence the catalytic activity. Oxides with basic properties, such as MgO, Al2O3, CeO2, are frequently used as carriers. One of the most promising materials for reforming of methane technologies are hydrotalcites, due to adjustable composition, acid-base properties and possibility of incorporation of various metals and complexes.

Open access
Acetylation of p-Aminophenol by Preyssler's anion [NaP5W30O110]14-, [NaP5 W29MoO110]14- with green condition at room temperature

Acetylation of p-Aminophenol by Preyssler's anion [NaP5W30O110]14-, [NaP5 W29MoO110]14- with green condition at room temperature

Synthesis of acetaminophen at green condition and room temperature in the presence of the Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.

Open access
Platinum dissolution and ethanol oxidation reaction on Pt-activated nickel foam in sodium hydroxide solution

Abstract

Electrochemical oxidation of ethanol becomes an important process of modern electrochemistry, due to its potential application into direct ethanol fuel cell technology. As rates of ethanol oxidation reaction (EOR) are significantly enhanced in alkaline media, employment of highly corrosion resistant under alkaline conditions, but non-noble metals becomes of superior practical importance. This communication article reports on the process of anodic dissolution of platinum, which is investigated on Pt activated, electrooxidized nickel foam electrodes, employed for ethanol oxidation reaction in 0.1 M sodium hydroxide solution. The above was revealed through the application of cyclic voltammetry and combined SEM/EDX (scanning electron microscopy and energy dispersive x-ray) spectroscopy examinations.

Open access
Technological aspects of vegetable oils epoxidation in the presence of ion exchange resins: a review

Abstract

A review paper of the technology basics of vegetable oils epoxidation by means of peracetic or performic acid in the presence of acidic ion exchange resins has been presented. The influence of the following parameters: temperature, molar ratio of acetic acid and hydrogen peroxide to ethylenic unsaturation, catalyst loading, stirring intensity and the reaction time on a conversion of ethylenic unsaturation, the relative percentage conversion to oxirane and the iodine number was discussed. Optimal technological parameters, mechanism of epoxidation by carboxylic peracids and the possibilities of catalyst recycling have been also discussed. This review paper shows the application of epoxidized oils.

Open access
PIV measurement of tube-side in a shell and tube heat exchanger

Abstract

In order to improve the performance of the shell and tube heat exchanger, a porous baffle and a splitter bar are employed in this research. Through the arrangement of the porous baffle in the tube-side inlet and the splitter bar in the tube, the flow distribution of liquid in the heat exchanger is improved. PIV technology is used to investigate the unsteady flow in the tube-side inlet and the outlet of different models. The porous baffle significantly improves the flow of fluid in the shell and tube heat exchanger, especially by eliminating/minimizing the maldistribution of fluid flow in the tube-side inlet. The performance of the arc baffle is better than that of the straight baffle. The splitter bar has a minimal effect on the flow field of the tube-side inlet, but it effectively improves the flow in the tube bundle and restrains the vortex generation in the tube-side outlet.

Open access
Assessment of the possibility of the methane to methanol transformation

Assessment of the possibility of the methane to methanol transformation

The methane to methanol conversion via esterification is an interesting method which makes it possible to eliminate the otherwise necessary phase of obtaining synthesis gas. On the basis of laboratory investigations mass balances for this process were determined. Preliminary assessment of the way of conducting the process and possibilities of practical applications of this technology was also made. It was pointed out that regardless of any possible modifications of methane to methanol conversion via esterification redundant sulfuric acid will always be produced during ester hydrolysis. Production of methanol from methane using this method can only be done when it is combined with producing other substances, which needs using H2SO4.

Open access
Dry single-stage method of sodium tripolyphosphate production – technological and economic assessment

Abstract

The study presents a technology of sodium tripolyphosphate (STPP) production with the use of a dry, single-stage method. The reacting substrates (concentrated wet-process phosphoric acid - WPPA and solid Na2CO3 ) are mixed with a recycled final product (STPP) in a mixer, then a „quasi-dry” mixture is calcined in a rotary kiln. Thanks to that, some stages of a classic method of STPP production are eliminated: one of the two-stage neutralization of the phosphoric acid with sodium carbonate at temperature ~80°C, filtration of the neutralised solution and its evaporation, as well as the stage of drying a solution of mono- and di-sodium orthophosphate in a spray dryer. According to the presented technical and economical analysis, the costs of STPP production using a single-stage dry method can be 10% lower compared to the classic method.

Open access
Reducing of on Polymerization Shrinkage by Application of UV Curable Dental Restorative Composites

Abstract

This manuscript describes dental compositions contain in-organic fillers, multifunctional methacrylates and photoinitiators. The main problem by application and UV curing process is the shrinkage of photoreactive dental materials during and after UV curing process. Total shrinkage of UV curable dental composites is a phenomenon of polymerization shrinkage, typical behavior for multifunctional methacrylates during polymerization process. The important factors by curing of dental composites are: kind and concentration of used methacrylates, their functionality, double bond concentration, kind and concentration of added photoinitiator and UV dose. They are investigated UV-curable dental compositions based on 2,2-bis-[4-(2-hydroxy-3-methacryxloyloxypropyl)phenyl]propane (Bis-GMA) and containing such multifunctional monomers as 1,3-butanediol dimethacrylate (1,3-BDDMA), diethylene glycol dimethacrylate (DEGDMA), tetraethylene glycol dimethacrylate (T3EGDMA), trimethylolpropane trimethacrylate (TMPTMA), polyethylene glycol 200 dimethacrylate (PEG200DA). Reduction of polymerization shrinkage of dental compositions is at the moment a major problem by dental technology.

Open access
Study of selected physical, chemical and biological properties of selected materials intended for contact with human body

Abstract

The purpose of the conducted study was to analyse new materials intended for contact with the human body in view of their physical, chemical and biological properties. The authors have put to test six commercially available materials, four out of which were composite polyamide 12-based materials, while two were polyurethanes. The examined materials were assessed in terms of the surface. Subsequently, their hardness and biocompatibility were tested. The authors devoted major attention to the tests of absorption and emissivity of water, the pH = 7.4 PBS buffer solution and pH = 4.3 artificial sweat in temperatures of 21°C and 37°C. The results of the tests have confirmed the non-toxicity of all the tested materials and allowed to provide their characteristics in terms of their surface, hardness, as well as absorption and emissivity of various body fluids. Both polyamide 12 and the tested polyurethanes are classified as thermoplastics that may be used in additive technology.

Open access
Bio-chemical methods in wasteprocessing

Bio-chemical methods in wasteprocessing

The mineral biotechnologies, the domain of which is primary raw material processing, are increasingly diversifying into some metallurgical areas. The presented results of the research carried out with metallurgical wastes from aluminium production, lead waste remaking and desulphurization zinc-ferrite-based sorbents regeneration prove the possibility of the use of bio-chemical methods. The results obtained and the proposed technologies applying bio-chemical processes enable a complex processing and use of waste sludge from aluminium production and the use of wastes from matte-based copper production for the production of hematite pigments. The use of microorganisms in the desulphurization sorbent regeneration processes allows to increase sorbent's efficiency and its repeated recycling.

Open access