Methane production from co-electrolysis products applying a microchannel reactor

This PhD thesis comprises the development of a polytropic microstructured methanation unit for conversion of CO/CO$_2$ mixtures. As part of the MINERVE Power-to-Gas project, conducted from 2012-2015, the developed reactor contributes to transformation of electrical surplus energy into chemical energy by using methane. The theory focuses on the examination of thermodynamic equilibria, methane formation mechanisms, catalyst degradation and kinetics. From a technological point of view, microreactors were identified as a promising tool due to the possibility of precise temperature control, which is key in the highly exothermic methanation reaction. The experimental procedure encompasses the catalyst behavior under variation of H$_2$/C-ratio, temperature and concentrations of CO and CO$_2$. Under CO methanation conditions, strong deactivation of the commercial Ni catalyst was observed, while almost no catalyst degradation was encountered under pure CO$_2$ methanation conditions. The assumption of deactivation by coke was supported with surface carbon and BET-surface decrease. Preferential methantion of CO was observed in CO/CO$_2$-mixtures with deactivation of catalyst being similar to that under CO conditions. Two microstructured packed bed reactors were developed showing few novelties in respect to temperature control and pressurized operation of both cooling and reaction zones. It could be shown, that the methanation of CO/CO$_2$-mixture is possible in one step by controlling the temperature of the reactor to a certain degree while evaporating the cooling water. Due to strong exothermicity of the methanation reaction, a partial overheating of the catalyst took place in both reactors, however, was clearly below adiabatic temperature rise. The hot spot occurrence pointed to heat transfer resistances either in the packed bed or the metal housing. The Prototype 2 showed superior performance compared to Prototype 1 due to additional cooling zone. The idea is filed as an international patent and a scaled-up version is successfully utilized in industrial application for methane generation. An extensive CFD study of Prototype 1 revealed the proper fluid distribution in the cooling zone and the positive effect of fins on heat transfer rate. Besides, valuable information could be extracted by using parameter variation in the packed bed and in the metal housing to determine the heat transfer bottleneck of the system, which could be narrowed to the separating metal wall. In the final chapter, a few literature models in respect to porosity, flow and heat conductivity distribution in packed beds were discussed, which served as a benchmark to successfully validate the presented meshing strategy using CFD. Ideal plug-flow behavior, as in case of microreactors, was found for packed beds, even at low d$_t$ /d$_P$-ratios, regarding flow and mass transport in the laminar and transition regions. Pronounced heat transfer issues could occur in the wall areas for Re<100

Identification of the effectiveness of associative rhizobacteria in spring wheat cultivation

Received: January 31st, 2021 ; Accepted: October 5th, 2021 ; Published: October 19th, 2021 ; Correspondence: [email protected] maximum increase in wheat yield (by 67% to the control), associated with a decrease in the root rot development by 19%, an increase in the productive bushiness by 18%, the spike weight by 26%, in the grains number per spike by 8% was noted when using the Bacillus subtilis strain 124-11; the strain effect on leaf diseases was insignificant (2–5%). The plants differed in the maximum changes (to control) in the total bushiness by 59%, the plants vegetative part weight by 27%, the flag leaf area by 21%, the pre-flag leaf area by 28%, the roots numbers and weight by 20% and 62%. After plants treatments with the Pseudomonas fluorescens strain SPB2137, the wheat maturation period was reduced by 9% (to the control), wheat yield increased by 58% due to a decrease in the development of root rot and septoria by 18%, the yellow rust pustules area by 44%; the productive bushiness and plant height increased by 25% and 19%, the plant vegetative weight by 21%, the spike length by 4%. The most expressed protective and growth-stimulating effect was shown by the Sphingomonas sp. K1B, which caused a maximum decrease (to the control) in the root rot and yellow rust development by 22% and 7%, the strips length by 22%, the pustules number in the strip by 29%, brown rust by 10%, septoria by 11%. Wheat plants were characterized by a large number and length of roots by 17% and 13%, root weight by 49%, a maximum increase in the nodal roots number and length by 15% and 17%; total bushiness by 34.5%; a maximum increase in plant vegetative weight by 37%; the spike length by 3%

Microbial inoculum development for ameliorating crop drought stress:A case study of Variovorax paradoxus 5C-2

Drought affects plant hormonal homeostasis, including root to shoot signalling. The plant is intimately connected below-ground with soil-dwelling microbes, including plant growth promoting rhizobacteria (PGPR) that can modulate plant hormonal homeostasis. Incorporating PGPR into the rhizosphere often delivers favourable results in greenhouse experiments, while field applications are much less predictable. We review the natural processes that affect the formation and dynamics of the rhizosphere, establishing a model for successful field application of PGPR utilizing an example microbial inoculum, Variovorax paradoxus 5C-2

Improving water resources management using different irrigation strategies and water qualities: Field and modelling study

The aim of this study was to investigate the effects of two different irrigation strategies, regulated deficit irrigation, RDI and partial root drying, PRD using surface freshwater (SW) and brackish treated wastewater (TWW) for maize and potato crops. The SALTMED model has been applied using the field measurements of two cropping seasons 2013 and 2014 at the Canale Emiliano Romagnolo, CER’s experimental farm located in Mezzolara di Budrio (Bologna, Italy). In 2013, PRD irrigated potato received 17% less irrigation water than RDI but produced nearly the same yield as under RDI. The water productivity, o naverage, was 11% higher for PRD compared with RDI. For maize 2014 season, the PRD strategy received almost 15% less irrigation water, but produced a yield only 6% lower than that of RDI and gave equal water productivity to RDI. Given that the two strategies received the same amount of rainfall the results favour the PRD over RDI. Had the site not received above average rainfall (258 mm in 2013 and 259 mm during the 2014 growing seasons), PRD might have produced higher yield and water productivity than RDI. In terms of model simulations, overall, the model showed a strong relationship between the observed and the simulated soil moisture and salinity profiles, total dry mater and final yields. This illustrates SALTMED model’s ability to simulate the dry matter and yield of C3 and C4 crops as well as to simulated different water qualities and different water application strategies. Therefore, the model can run with “what if” scenarios depicting several water qualities, crops and irrigation systems and strategies without the need to try them all in the field. This will reduce costs of labour and investment

Synthesis and Testing of Abscisic Acid with Predominant Replacement of Protium Atoms by Tritium in the Cyclohexene Moiety

© 2018, Pleiades Publishing, Inc. Abstract: A procedure for tritiation of predominantly the cyclohexene moiety of abscisic acid was developed. Tritium was introduced by isotope exchange reaction with 100% tritiated water at 220°C in the presence of diisopropylethylamine. The yield of abscisic acid was 50%, and the specific activity was 30.5 Ci/mmol. The labeled product was tested. It was shown that tritiated abscisic acid synthesized by the proposed method did not differ from the unlabeled precursor and could be used for biological assays

Complete genome sequence of the abscisic acid-utilizing strain Novosphingobium sp. P6W

The phytohormone abscisic acid (ABA) plays multiple roles in plant survival and fitness. Significant quantities of ABA are constantly introduced into soil via root exudation, root turnover and incorporation of abscised shoot tissues. In addition, some phytopathogenic fungi synthesize ABA in the course of plant-microbe interactions. The accumulation of soil ABA can inhibit seed germination and root growth but despite this observation, the biochemical pathways of ABA conversion by microorganisms and genetic determinants of the process remain unknown. Here we report on the complete genome sequence of strain P6W, an ABA-utilizing isolate of the genus Novosphingobium. Strain P6W was isolated from the rhizosphere of rice (Oryza sativa L.) seedlings using a selective ABA-supplemented medium. The genome of strain P6W consists of 6,606,532 bp, which includes two chromosomes and two plasmids. It comprises of 5663 protein-coding genes and 80 RNA genes. ANI values calculated based on the analysis of nine previously sequenced genomes of members of the genus Novosphingobium ranged from 77 to 92 %, which suggests that strain P6W is potentially a new species of the genus Novosphingobium. Functional annotation of genes in the genome of strain P6W revealed a number genes that could be potentially responsible for ABA degradation.1-