Process gas dependence of the spin Peltier effect in Pt/Fe3O4 hybrid structures

The spin Peltier effect (SPE) in Pt/Fe3O4 hybrid structures with epitaxial Fe3O4 layers synthesized by reactive sputtering using two different process gases, Ar/O2 and Kr/O2, was investigated. The magnitude of the SPE-induced temperature modulation for the Fe3O4 film grown using Kr/O2 was approximately 40% larger than that grown using Ar/O2 despite almost the same crystalline structures and magnetic and electric properties of the films. The enhancement of the SPE signal for the film grown with Kr/O2 can be attributed to an increase in the spin current injected into the Fe3O4 film owing to its large roughness.

Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements

The paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically modified during the warming-up process. A typical situation, when such a modification is processed, is the regulation of the medium flow through two-way or three-way valves or applying additional heat source. Moreover, the presented method does not require the transformation of the differential equations, describing the operation of individual elements, into a linear form, which significantly facilitates analytical work and makes it more flexible. The example of analysis of the operation of water installation used for controlling temperature of the process gases in a chemical installation shows the functionality and flexibility of the method. The adopted calculation schematics enable changing the direction of the heat flow while the heat exchanger is in operation. Additionally, the sequence of calculation processed in modules describing operation of installation elements is elective (there is no situation that output parameters from one element are used as input parameters for other element in the same calculation step).

Triacetoneamine-derivates (EvAs) for CO2-absorption from Process Gases

New amines for reactive absorption of CO2 from process gases were investigated in a comprehensive experimental screening. All studied amines are derivates of triacetoneamine and differ only in the substituent of the triacetoneamine ring structure. The amines are abbreviated by the acronym EvA with a consecutive number, designating the derivate. About 50 EvAs were considered in this work from which 26 were actually synthesized and investigated in aqueous solution.The following properties were studied: solubility of CO2, rate of absorption of CO2, liquid–liquid and solid–liquid equilibrium, foaming behavior, dynamic viscosity, and acid constants. The nine most promising EvAs were evaluated with the NoVa short-cut method (Vasiliu et al., 2020). The method yields estimates for the specific energy demand and recirculation rate for a given purification task. Two typical purification tasks were considered: the CO2-removal from natural gas and from synthesis gas, respectively. Some of the EvAs showed significantly improved performance compared to monoethanolamine (MEA) and a solvent-blend of methyl-diethanolamine and piperazine (MDEA/PZ).

THE PROSPECTIVE USE OF METHYLDIETHANOLAMINE IN THE TREATING OF PROCESS GASES FOR HYDRIGEN SULFIDE REMOVAL ON THE DIESEL FUEL HYDROCLEANING UNIT JSC «ANHK»

It was considered the possibility of using methyldiethanolamine solution instead of monoethanolamine solution for hydrogen sulfide removal from process gases in diesel fuel hydrocleaning unit JSC «ANHK». It is demonstrated some advantages and disadvantages methyldiethanolamine-based circulating absorbent in comparison of monoethanolamine-based absor bent.

Enrichment of Integrated Steel Plant Process Gases with Implementation of Renewable Energy

The steel industry is one of the most important industry sectors, but also one of the largest greenhouse gas emitters. The process gases produced in an integrated steel plant, blast furnace gas (BFG), basic oxygen furnace gas (BOFG) and coke oven gas (COG), are due to high shares of inert gas (N2) in large part energy poor but also providing a potential carbon source (CO and CO2) for the catalytic hydrogenation to methane by integration of a Power-to-Gas (PtG) plant. Furthermore, by interconnecting a biomass gasification, an additional biogenic H2 source is provided. Three possible implementation scenarios for a PtG and a biomass gasification plant, including mass and energy balances were analysed. The scenarios stipulate a direct conversion of BFG and BOFG resulting in high shares of N2 in the feed gas of the methanation. Laboratory experimental tests have shown that the methanation of BFG and BOFG is technically possible without prior separation of CO2. The methane-rich product gas can be utilised in the steel plant and substitutes for natural gas. The implementation of these renewable energy sources results in a significant reduction of CO2 emissions between 0.81 and 4.6 Mio tCO2,eq/a. However, the scenarios are significantly limited in terms of available electrolysis plant size, renewable electricity and biomass.

PURIFICATION OF SMOKE AND PROCESS GASES IN DIRECT-FLOW CYCLONES

In this work, gas velocity profiles in the separating chamber of a direct-flow cyclone are obtained, and a method for calculating its efficiency is proposed. The method allows us to trace the influence of the geometric parameters of the chamber, the particle size and the gas flow rate on the degree of its purification. The calculation results are confirmed by numerous experiments

Effect of the Process Gas and Scan Speed on the Properties and Productivity of Thin 316L Structures Produced by Laser-Powder Bed Fusion

The development of the laser powder bed fusion (L-PBF) process to increase its robustness and productivity is challenged by ambitious design optimizations, such as thin wall structures. In this study, in addition to the effect of commonly used gases as Ar and N2, increased laser scanning speed and new process gases, such as helium, were successfully implemented. This implementation allowed to build 316L stainless steel components with thin walls of 1 mm thickness with an enhanced build rate of 37 pct. The sample size effect and the surface roughness were held responsible for the reduction in strength (YS > 430 MPa) and elongation (EAB > 30 pct) for the 1 mm samples studied. Similar strength was achieved for all process gases. The increased scanning speed was accompanied by a more random texture, smaller cell size, and grain size factor along the building direction when compared to the material built with the standard laser parameters. Stronger preferential orientation 〈101〉 along the building direction was observed for material built with standard parameters. Finally, the use of helium as a process gas was successful and resulted in reduced cell size. This finding is promising for the future development of high strength 316L stainless steel built with high build rates.

INFLUENCE OF TECHNOLOGICAL MODES OF THERMOCHEMICAL TREATMENT ON THE QUALITY OF STRENGTHENING OF HIGHLY LOADED GEARS

The study of changes in the microstructure, thickness and hardness of diffusion coatings obtained by varying the carbon potential and the consumption of process gases at different stages of cementation and nitrocarburizing was carried out. The possibility of reducing energy consumption and the duration of thermochemical treatment with the provision of the required effective thickness of the hardened layer is established.