Optimisation of Propane Production from Hydrothermal Decarboxylation of Butyric Acid Using Pt/C Catalyst: Influence of Gaseous Reaction Atmospheres

The displacement and eventual replacement of fossil-derived fuel gases with biomass-derived alternatives can help the energy sector to achieve net zero by 2050. Decarboxylation of butyric acid, which can be obtained from biomass, can produce high yields of propane, a component of liquefied petroleum gases. The use of different gaseous reaction atmospheres of nitrogen, hydrogen, and compressed air during the catalytic hydrothermal conversion of butyric acid to propane have been investigated in a batch reactor within a temperature range of 200–350 °C. The experimental results were statistically evaluated to find the optimum conditions to produce propane via decarboxylation while minimizing other potential side reactions. The results revealed that nitrogen gas was the most appropriate atmosphere to control propane production under the test conditions between 250 °C and 300 °C, during which the highest hydrocarbon selectivity for propane of up to 97% was achieved. Below this temperature range, butyric acid conversion remained low under the three reaction atmospheres. Above 300 °C, competing reactions became more significant. Under compressed air atmosphere, oxidation to CO2 became dominant, and under nitrogen, thermal cracking of propane became significant, producing both ethane and methane as side products. Interestingly, under a hydrogen atmosphere, hydrogenolytic cracking propane became dominant, leading to multiple C–C bond cleavages to produce methane as the main side product at 350 °C.

Development of the Method for Forecasting and Calculating the Operation of Sorption Systems for Purifying the Generator Gas Based on Dolomite Use. Part I

A trend towards energy diversification creates the expansion of small energy facilities that involve the production of solid fuel generator gas, rather than its direct combustion. The economic indicators of such facilities significantly depend on the efficiency of the generator gas purification. A promising sorbent for the purification of the generator gas is dolomite. When working as a sorbent, dolomite particles usually form a layer, through which the generator gas that is heating them is filtered. The objective of the study is to determine kinetic parameters of the thermal decomposition of dolomite, depending on the size of the sample. It was achieved using the thermogravimetric study of the thermal decomposition of single dolomite particles under static conditions at various temperatures. The most significant scientific result was that a dependence of the kinetic parameters of the gross reaction on the size of the initial particle is revealed, and a regression equation was proposed for its quantitative assessment. In addition, since the heat treatment process of the material was fairly long lasting, and the sizes of the particles allowed them to be referred to thermally thin bodies, it was inferred that the effect of a grain size on the reaction kinetics should be explained through the description of the evacuation process of gaseous reaction products from the material. The significance of the results of the study lies in the fact that a particle size must be considered as a factor that affects the progress of the technological process, which increases the reliability of the calculation of sorption-catalytic systems based on the use of dolomite.

Cracking of the paraffins on catalysts from natural zeolite of Kazakhstan Shankanay field

Cracking of paraffins was held to obtain long chain α-olefins using the catalysts from natural zeolite of Shankanay field modified with 1N HCl at the temperature range of 500-570°С and atmospheric pressure on a fixed layer. Liquid and gaseous reaction products were analyzed by gas chromatography; regeneration of the catalyst was carried out with a steam-air mixture until total absence of CO2 in the contact gases. To evaluate the structure and texture of the obtained catalysts, the methods of Mössbauer spectroscopy, X-Ray diffractometry analysis, and elemental analysis using scanning electron microscopy were used. As results, zeolite modification allowed doubling the activity of the catalysts and increasing the selectivity by 23.8-44.8%. The group compositions of olefins, alkanes and gaseous products were detected. Iron form under α-Fe2O3, ε-FeOOH and γ-FeOOH was present. The modified and blank form of catalysts under 1N hydrochloric acid solution washing phase content was detected; partial destruction of the crystalline carcass of clinoptilolite was observed.

Process Analysis of Main Organic Compounds Dissolved in Aqueous Phase by Hydrothermal Processing of Açaí (Euterpe oleraceae, Mart.) Seeds: Influence of Process Temperature and Biomass-to-Water Ratio

This work aims to investigate systematically the influence of process temperature and biomass-to-water ration on the chemical composition of aqueous and gaseous phases and mass production of chemical by hydrothermal processing of Açaí (Euterpe Oleraceae, Mart.) seeds. The hydrothermal carbonization carried out at 175, 200, 225, and 250 °C, 2 °C/min, biomass-to-water ratio of 1:10, and at 250 °C, 2 °C/min, and biomass-to-water ratios of 1:10, 1:15, and 1:20, in technical scale. The chemical composition of aqueous phase determined by GC and HPLC and the volumetric composition of gaseous phase by using an infrared gas analyzer. For constant biomass-to-water ratio of 1:10, the yields of solid, liquid, and gaseous phases varied between 53.39 and 37.01% (wt.), 46.61 and 59.19% (wt.), and 0.00 and 3.80% (wt.), respectively. The yield of solids shows a smooth exponential decay with temperature, while that of liquid and gaseous phases a smooth growth. By variation of biomass-to-water ratios, the yields of solid, liquid, and gaseous reaction products varied between 53.39 and 32.09% (wt.), 46.61 and 67.28% (wt.), and 0.00 and 0.634% (wt.), respectively. The yield of solids decreases exponentially with increasing water-to-biomass ratio and that of liquid phase increases in a sigmoid fashion. For constant biomass-to-water ratio, the concentrations of Furfural and HMF decrease drastically with temperature, reaching a minimum at 250 °C, while that of phenols increases. In addition, the concentrations of CH3COOH and total carboxylic acids increase, reaching a maximum at 250 °C. For constant process temperature, the concentrations of aromatics vary smoothly with the temperature. The concentrations of furfural, HMF, and cathecol decrease with temperature, while that of phenols increases. The concentrations of CH3COOH and total carboxylic acids decrease exponentially with temperature. Finally, for the experiments with varying water-to-biomass ratios, the productions of chemicals (furfural, HMF, phenols, cathecol, and acetic acid) in the aqueous phase is highly dependent on the biomass-to-water ratio.

Effects of the Nail Geometry and Humidity on the Nail Penetration of High-Energy Density Lithium Ion Batteries

Internal short-circuit tests were carried out in a battery safety investigation chamber to determine the behavior of batteries during the nail penetration test. So far, systematic investigations regarding the test setup and its influence are rarely found in the literature. Especially, to improve the comparability of the multitude of available results, it is essential to understand the effects of the geometric, operating and ambient parameters. In this study commercial lithium ion batteries with a capacity of 5.3 and 3.3 Ah were used to study the influence of the varied parameters on the voltage drop, the development of surface temperatures and of infrared active gas species. We studied both the influence of the geometry of the penetrating nail and concentration of water in the inert atmosphere especially on the quantities of the reaction products under variation of cell capacity. It could be shown that the geometry of the nail, within certain limits, has no influence on the processes of the thermal runaway of high energy density lithium ion batteries (LIBs). However, a change in capacity from 5.3 to 3.3 Ah shows that in particular the gaseous reaction products differ: The standardized gas concentrations show a higher measurable concentration of all gases except CO for the 3.3 Ah LIBs. This circumstance can be explained by the intensity of the reactions due to the different battery capacities: In the 5.3 Ah cells a larger amount of unreacted material is immediately discharged from the reaction center, and by the different available amounts of oxidizing reaction partners. An increase of the water content in the surrounding atmosphere during the thermal runaway leads to a reduction of the measurable gas concentrations of up to 36.01%. In general, all measured concentrations decrease. With increased water content more reaction products from the atmosphere can be directly bound or settle as condensate on surfaces.

MODEL AND METHOD OF CONTROLLED PYROLYSIS OF ORGANIC SUBSTANCES OF VARIABLE COMPOSITION

The issues of organization of the process of slow pyrolysis of organic substances, in the general case of unknown and variable composition, are considered. The relevance of the work is determined by considering the possibility of using various organic waste (domestic, agricultural, industrial) without their preliminary sorting and drying to obtain secondary energy resources of a known (controlled) composition. The novelty of the work is due to the development of a model for the method of controlled pyrolysis or gasification of organic substances with a minimum amount of solid residues at a maximum calorific value of the resulting mixture of combustible gases. A process based on filtration combustion in superadiabatic mode is considered. In existing devices, when this mode is implemented, a counter flow of the feedstock and reaction products is organized. As a result, a part of the water vapor generated at the drying stage is part of the mixture of reaction products and, accordingly, reduce their energy value. The scheme of the process proposed for consideration is based on the organization of the associated flow of feedstock and reaction products. As a result, the resulting carbon dioxide and water vapor are used as additional oxidizing agents. As a result, the carbonaceous residue decreases with a simultaneous increase in the composition of the mixture of gaseous products of carbon monoxide and hydrogen. A scheme for real-time monitoring of the composition of the feedstock during pyrolysis (gasification) is proposed. Knowledge of the composition makes it possible to control the process of its processing in order to: a) organize the optimal gasification process in terms of maximizing the amount and energy value of the mixture of gaseous reaction products; b) control the consumption of the processed feedstock in order to produce the required amount of product gas at any given time.

Analysis Method of Black Liquor Pyrolysis and Gasification Using Deconvolution Technique to Obtain the Real Time Gas Production Profile

In thermal reaction experiments, e.g., pyrolysis, combustion, and gasification, the gas released from the reaction can be analyzed in gas measuring instruments. There will be some time delay due to the relatively long gas travel from the reactor to the analyzers. Besides, there can be some time lag in the gas measuring instrument. Gas dispersion may furthermore occur and thus alter the gas concentration profile. The observed gas concentration, therefore, can be very different from the original gaseous reaction products profile. A mathematical procedure called deconvolution technique will be used to get the original gaseous reaction products concentrations profile. The deconvolution technique is based on the assumption that original data have been altered by a transfer function to yield observed data. By the deconvolution techniques, the transfer function for each data set will be calculated and then can be used to compute the original data. In this study, the deconvolution technique was applied to the concentration profile of gaseous products from black liquor pyrolysis and gasification reactions measured by gas analyzers instruments to obtain the real-time gas concentration profile during the processes. Tracer gases are injected in the reactor To facilitate the deconvolution calculation, and their concentration profiles observed in the measuring instruments are recorded. Gaseous products that are analyzed are CO2, CO, CH4, SO2, and H2S. This technique can successfully provide the real-time gas production concentration profile from the black liquor pyrolysis and gasification reaction. A B S T R A KDalam reaksi termal seperti pirolisis, pembakaran, dan gasifikasi, gas hasil reaksi dapat dianalisis dengan instrumen analisis gas. Akan ada penundaan waktu deteksi karena waktu tempuh dari reaktor ke alat analisis. Ada juga tambahan waktu karena pemrosesan dalam instrumennya. Dispersi gas juga mungkin terjadi yang akan mengubah profil konsentrasi gas.Profil konsentrasi gas yang terdeteksi bisa jadi akan sangat berbeda dengan profil produksi gas yang sebenarnya. Untuk mendapatkan profil konsentrasi yang sebenarnya, dapat digunakan sebuah prosedur matematika yang disebut dekonvolusi. Dalam prosedur ini diasumsikan profil gas telah diubah oleh sebuaf fungsi transfer sehingga menghasilkan profil gas terboservasi. Dengan teknik dekonvolusi, fungsi transfer ini akan dicari sehingga bisa dipergunakan untuk menghitung profil gas sebenarnya. Dalam penelitian ini profil gas hasil reaksi pirolisis dan gasifikasi lindi hitam yang terdeteksi dalam instrumen analisis gas akan didekonvolusi untuk mendapatkan profil produksi gas yang sebenarnya. Untuk itu sebuah gas pendeteksi diijeksikan ke dalam reaktor dan profil konsentrasinya diukur dengan instrumen analisis. Gas yang dianalisis adalah CO2, CO, CH4, SO2, and H2S. Dengan teknik ini profil produksi gas yang sebenarnya dari reaksi pirolisis dan gasifikasi berhasil diperoleh.

Investigation of the Laser Radiation Effects on Lignite with the Products Analysis by Mass Spectrometry

In this paper, one studied the effect of pulsed laser radiation (1064 nm, 120 μs) on lignite. The method of mass spectrometry was used to analyze the formed gaseous reaction products after the exposing of coal samples to the laser radiation. The pressed out of the pre-milled coal particles tablets were used as samples. In the mass spectra of the reaction products of laser radiation of the samples, the peaks with a mass to ion charge ratio m/z = 2, 18, 44 were detected, that corresponds to the main peaks of H2, H2O, and CO2 molecules. The pattern of formation of the end products CO2, H2, H2O when heating a sample of coal by laser radiation is proposed. The energy release factor is calculated, which is defined as the ratio of the calorific value, released during combustion of the sample to the dose of energy absorbed by the sample during irradiation.

Investigations of Graphite Particle Interaction with Metallic Surfaces

Previous studies on the safety of gas-cooled high-temperature reactors (HTR) have analyzed the corrosion and oxidation behavior of the primary circuit components under normal and accident conditions. Through the use of graphite components, graphite particles can be formed by mechanical and chemical means whose influence on the structural change of metal surfaces must be analyzed in a comprehensive manner. The dust resuspension and deposition in tank geometry (DRESDEN-TANK) test facility was set up to thermally anneal metallic samples (Alloy 800H, Inconel 617) loaded with graphite particles under typical HTR conditions (helium, 750 °C, 6 MPa) for the investigation of interactions over a long-term range. In addition to the carrying out of a description of the processes occurring on the material surface, the gaseous reaction products have been analyzed. The results show that the presence of graphite particles in the near-surface layer has a significant impact on corrosion processes due to thermally-induced interactions. In this case iron and chromium are degraded in the metallic alloys, which leads to a structural change in the near-surface layer. Furthermore, the graphite particles significantly influence the formation of the oxide layers on the alloys; for example, they influence the formation speed of the layer and the layer height. The originally deposited particles thus exhibit a chemically-altered composition and a different geometric shape.

Experimental study of the dynamics of microwave pyrolysis of peat

The work is devoted to the study of the effect of high-power microwave radiation on sphagnum peat. To implement the microwave pyrolysis process, a laboratory unit based on a coaxial resonator has been created. An industrial magnetron with a frequency of 2.45 GHz was used as a source of microwave radiation. Samples of gas, liquid and solid phases were obtained and analyzed. Studies of soft microwave pyrolysis in conditions of constant removal of gaseous reaction products were carried out. A comparative analysis of the products obtained in microwave pyrolysis and pyrolysis with thermal heating was performed. The aim of the research is to create highly efficient environmentally friendly technologies for processing biofuels with a high yield of combustible gases, suitable for further use in power plants, as well as the production of resinous fraction and carbon residue.