Using Danish linked employer–employee data, this study examines the importance of access to higher-paying firms in the wage assimilation process among immigrants during their 25-year tenure in Denmark. Upon their arrival, immigrant workers in Denmark earn substantially lower wages than their native counterparts. However, this wage gap diminishes rapidly within the first 5–10 years, particularly among more disadvantaged immigrant groups (non-OECD and female immigrants). Immigrants who enter the labour market early have higher earnings capacity than those who enter later, but this trend reverses after 15 years. The transition to higher-paying firms constitutes a crucial factor in wage assimilation during the initial 5 years, yet it does not account for wage growth beyond this period. Additionally, this study offers suggestive evidence that Danish firms’ wage policies vary based on the duration since migration, and these differences significantly contribute to the wage assimilation process.

This paper provides a comprehensive analysis of the costs of job displacement in energy-intensive industries in selected OECD countries. Based on harmonised linked employer-employee data from 14 OECD countries, we estimate the effect of job displacement in three energy-intensive industries, namely energy supply, heavy manufacturing and transport, compared to other industries. We find that workers displaced from energy supply and heavy manufacturing, experience larger earnings losses compared with workers in non-energy-intensive and transport sectors. Larger earnings losses mainly result from weaker re-employment outcomes in terms of wages and job instability but also challenges with finding another job. They reflect significant differences in the composition of workers and firms in energy supply and heavy manufacturing and the rest of the economy. Displaced workers in these sectors tend to be older, are less skilled and more likely to be previously employed in high-wage firms.

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Structured Fischer–Tropsch synthesis catalysts were tested in tubular reactors of industry-standard diameters of 0.5 or 0.75 inches. The structured catalyst bed was manufactured by the obturation of a straight bunch of graphite-based extrudates (D = 1.5 mm, L = 30 mm). A conventional loose bed of granulated catalyst (D = 1.5 mm, L = 3 mm) was tested as a reference. In a 1000–3000 h−1 syngas space velocity range, structured and loose catalyst bed testing showed no significant differences in their main catalytic parameters. Nevertheless, their C5+ hydrocarbon group composition was quite different, i.e., the alkene fraction rose from 9 to 23%, while n-alkanes dropped from 81 to 64%. This could be a result of secondary reaction intensification in the conventional loose bed due to its zeolite acid site’s higher availability. Further FTS testing of the structured catalysts in 4000–6000 h−1 manifested distinctive limits in C5+ productivity for 0.5 and 0.75 inches of 512 kg C5+/(m3 reactor·h) and 362 kg C5+/(m3 reactor·h), respectively. This may be explained by limitations in structured bed thermal conductivity. It suggests that the arrangement of extrudates in the structured catalyst can significantly affect the reaction heat and mass transfer conditions and affords new opportunities for group composition control by means of catalyst bed organization.

An Erratum to this paper has been published: https://doi.org/10.1134/S2070050423030121

What drives differences in pay between firms? To answer this question, we build a harmonised cross-country linked employer-employee data set to analyse the role of firms in wage inequality since the 2000s in 20 OECD countries. The main finding is that, on average across countries, changes in the dispersion of average wages between firms explain about half of the changes in overall wage inequality. Two-thirds of these changes in between-firm wage inequality, i.e. about a third of overall wage inequality, are accounted for by changes in wage premia, i.e. the part of wages that is determined by the firm rather than the characteristics of its workers. The contribution of wage premia tends to be larger in countries with decentralised collective bargaining systems and lower levels of job mobility. The remaining third, i.e. a sixth of overall wage inequality, can be attributed to changes in workforce composition, including the sorting of high-skilled workers into high-paying firms. These results suggest that firms play an important role in explaining wage inequality as wages are determined, to a significant extent, by firm wage-setting practices rather than being exclusively determined by workers’ earnings characteristics.

The deposition of nanostructured carbon particles on the surface of a catalyst (carburization) is routinely considered an inalienable and undesirable secondary process in Fischer–Tropsch synthesis. However, very little is known about the actual role of the nanocarbon particles and how they influence catalysis. This paper reports research on the influence of carbon deposition on the performance of a cobalt-based Fischer–Tropsch-synthesized catalyst in an industrial-scale fixed-bed reactor (length—6000 mm, inner diameter—16.5 mm). The comparison of the structure and catalytic performance of a pelletized cobalt catalyst with the same catalyst, which was preliminary carburized, is presented. Pellet pore structure, catalyst surface, cobalt cluster morphology and the main catalytic properties (CO conversion, C5+ hydrocarbon productivity and selectivity to C5+ hydrocarbons and CH4 formation) were investigated. It is shown that the primary pre-carburization effect is a result of the physical blockage of the catalyst pore structure not followed by drastic changes in the cobalt cluster’s structure.

Some kinetic parameters of Fischer–Tropsch synthesis (FTS) were determined in the presence of a granular cobalt/zeolite catalyst. Usually, kinetic studies of granular catalysts are considered to be complicated by external and internal diffusion. We managed to obtain a catalyst with a special structure of the active surface, where sites active in FTS are isolated from each other due to the environment of inactive spinel CoAl2O4 and inter-site transport is provided by an extensive intragranular graphitic network serving simultaneously as a heat-conductive medium. As a result, FTS proceeded in the kinetic region. It was found that the reaction kinetics obey the Arrhenius law; whereas, the activation energy is different in different temperature ranges, i.e., 118.2 kJ/mol in the range of 180–210 °C, and 173.6 kJ/mol in the range of 232–243 °C. This behavior is determined by the presence of zeolite, which becomes active in the secondary transformations of FTS products at temperatures beyond 210 °C.

In this work, several ways to decrease the deactivation degree were proposed. To prevent local overheating, exfoliated graphite was used as a heat-conductive additive in catalyst composition. To decrease the deposition of heavy waxes, H-Beta zeolite was used for secondary reactions intensification and decreasing hydrocarbons chain length in the product. In this work, pelletized zeolite-containing cobalt catalyst with exfoliated graphite as a heat-conductive additive was investigated. The test run was 2200 h long and included continuous synthesis in a 6-meter high pilot reactor. The deactivation degree after 2200 h of the test run was 13%. The investigation of catalyst samples after synthesis by means of scanning electron microscopy showed that heavy hydrocarbons did not block the pore structure of catalytic pellets. Deactivation of cobalt catalyst was decelerated seriously due to zeolite-induced decrease in molecular weight of formed hydrocarbons. Investigation of catalysts before and after the test by means of transmission electron microscopy and X-ray diffraction analysis showed an increase in the size of clusters by 3-5 times, which is another important cause for catalyst deactivation. As a result, it was found that investigated cobalt catalyst for Fisher-Tropsch synthesis has a low deactivation rate. Its implementation in the industry can help gaining better economic performance for the synthetic fuel production process.

The effect of the dilution of a synthesis gas with nitrogen on the activity, selectivity and productivity of a Fischer–Tropsch reactor with a fixed bed of granular catalyst during synthesis on a pilot plant of a full cycle for the conversion of natural gas into synthetic oil is studied experimentally. Experimental data are presented that were obtained at different contents of nitrogen in the synthesis gas: up to 2, 50, and 70%. Analysis of the experimental data shows that diluting the synthesis gas contributes to an increase in the selectivity to C5+, and a decrease in the selectivity to methane. A drop in the reactor’s productivity observed upon the dilution of synthesis gas can be compensated for by increasing the consumption of synthesis gas. The negative effect of decrease in the pressure of FT synthesis from 2 to 1.5 and 1.0 MPa on the catalytic FT synthesis performed on a twice-diluted synthesis gas at a synthesis gas space velocity of 4000 h–1 is demonstrated.

The introduction of exfoliated graphite into pelletized Co-based catalysts affects in the most positive way both catalytic and physico-chemical properties. Unlike other carbons, the exfoliated graphite allows combination of extended surface with high thermal conductivity. An open-ended system of slit-type pores is revealed by X-ray tomography. Electron microscopy shows graphitic platelets forming an all-penetrating heat-conductive frame. Element distribution analysis shows that this catalyst cannot be considered as a cobalt-on-carbon catalyst since the graphitic component carries insignificant amount of cobalt and serves as a heat-conductive frame only. Thermal conductivity of a catalyst with graphite frame is 2 times higher than that of its industrial predecessor with Al metal frame and 30 times higher than that of a catalyst without heat-conductive additive. Testing in exothermal Fischer-Tropsch synthesis shows a favorable influence of the graphitic additive, i.e. such catalyst shows productivity of 455 g/kg/h at GHSV of 3000 h(-1).

A cobalt catalyst supported on titania-doped silicon carbide for the Fischer – Tropsch synthesis was synthesized and comprehensively studied using various physicochemical methods. The dynamics of behavior and deactivation of the catalyst, which showed a stable operation for 1500 hours, was studied in a continuous pilot-plant lifecycle test with periodic variation of flow rate, syngas pressure and process temperature. This catalyst has two types of active sites on which products with different parameters of the Schulz – Flory distribution are formed. Depending on the process mode, the efficient formation of «soft waxes» or products with a higher molecular weight can occur.

A cobalt catalyst supported on titania-doped silicon carbide for the Fischer – Tropsch synthesis was synthesized and comprehensively studied using various physicochemical methods. The dynamics of behavior and deactivation of the catalyst, which showed a stable operation for 1500 hours, was studied in a continuous pilot-plant lifecycle test with periodic variation of flow rate, syngas pressure and process temperature. This catalyst has two types of active sites on which products with different parameters of the Schulz – Flory distribution are formed. Depending on the process mode, the efficient formation of «soft waxes» or products with a higher molecular weight can occur.

The effect of syngas dilution with nitrogen on the activity, selectivity and capacity of the Fischer–Tropsch reactor with a fixed granulated catalyst bed was studied during the synthesis at the integrated pilot plant for conversion of natural gas to syncrude. Experimental data were obtained at different nitrogen content in syngas: up to 2, 50 and 70 %. The analysis of experimental data shows that the dilution of syngas increases the selectivity to C5+ and decreases the selectivity to methane. The decrease in the reactor capacity observed upon dilution of syngas can be compensated by increasing the syngas flow rate. A decrease in the pressure of the Fischer–Tropsch synthesis from 2 to 1.5 and 1.0 MPa was shown to exert a detrimental effect on the catalytic performance of the process carried out with a twofold dilution of syngas at its hourly space velocity of 4000 h–1.

A cobalt Fischer–Tropsch synthesis catalyst supported on titania-doped silicon carbide is synthesized and comprehensively studied by a number of physicochemical means. The dynamics of the behavior and deactivation of the catalyst was studied after its stable operation for 1500 h during continuous experimental resource testing with a periodic change in the syngas flow rate and pressure and the process temperature. This catalyst has two types of active sites, on which products with different Schulz–Flory distribution parameters form. Depending on the process regime, the effective formation of soft waxes or more high-molecular-weight products is possible.