Search results for "Scale-up"
showing 10 items of 21 documents
Dažu ivabradīna sintēzes stadiju pētījumi
2018
Dažu ivabradīna sintēzes stadiju pētīšana. Lugovskojs R., zinātniskie vadītāji MSc. Reine I. un Dr. chem. doc. Kļimenkovs I. Bakalaura darbs, 36 lappuses, 25 attēli, 3 tabulas, 24 literatūras avoti. Latviešu valodā. Darbā ir pētītas triju svarīgo ivabradīna starpproduktu - 7,8-dimetoksi-1H-benzo[d]azepin-2(3H)-ona, 3-(3-hlorpropil)-7,8-dimetoksi-1H-dihidro-2H-3-benzo[d]azepin-2(3H)-ona un dehidroivabradīna iegūšanas metodes ar mērķi atrast optimālus reakcijas apstākļus, kas piemēroti sintēzes veikšanai rūpnieciskā mērogā. Darbā ir apkopota pieejamā literatūra par ivabradīna un tā svarīgāko starpproduktu iegūšanas metodēm. Īpaši ir pētīta 7,8-dimetoksi-1H-benzo[d]azepin-2(3H)-ona alkilēšana,…
Current Problems in the Modelling of Photochemical Reactors
1985
Photochemical reactors are examined from the point of view of the main problems connected to their modelling. By distinguishing the diverse meanings of kinetic models and the varied objectives in establishing models, a particular attention is devoted to the following aspects of homogeneous photoreactors: steady state condition, effect of stirring and mixing, effect of the shape of the reactor and of the position of the light source, light emission models, scale up. For the heterogeneous systems only general considerations on kinetic models in heterogeneous photocatalysis and on the problems related to the use of fluidized bed photoreactors are done.
Gas-liquid mass transfer rates in unbaffled tanks stirred by PBT: scale-up effects and pumping direction
2018
Abstract Unbaffled stirred tanks are increasingly recognized as a viable alternative to common baffled tanks for a range of applications such as biochemical, food or pharmaceutical processes where the presence of baffles is undesirable for some reason. In this work, the mass transfer performance of unbaffled stirred tanks with pitched blade turbine, operating either in up-pumping or down-pumping mode, was investigated. The influence of impeller size and liquid viscosity were also investigated. The mass transfer intensity was measured by means of the Simplified Dynamic Pressure. Method The measurements concerned both coalescent and non-coalescent (viscous) batches. Results confirm that incre…
Electrochemical conversion of CO2 to HCOOH at tin cathode in a pressurized undivided filter-press cell
2018
Abstract The electrochemical reduction of carbon dioxide to formic acid was performed for the first time in a pressurized filter-press cell with a continuous recirculation of the electrolytic solution (0.9 L) at a tin cathode. It was shown that the performances of the system are comparable or slightly better than that of a batch system with a smaller volume (0.05 L). The selection of proper values of both current density and CO2 pressure allowed to achieve quite high values of faradaic efficiencies. Long-time electrolyses have shown that the system is stable and that it can allow to generate quite high concentrations of HCOOH (about 0.4 M).
Economic analysis of the scale-up and implantation of a hollow fibre membrane contactor plant for nitrogen recovery in a full-scale wastewater treatm…
2021
[EN] Nitrogen recovery technologies such as the hollow fibre membrane contactor are now being developed. However, an economic analysis is needed prior to their full-scale application in wastewater treatment plants. The aim of this study was to analyse the economic and environmental aspects of scaling-up this method. To achieve it, a full-scale 40,000 m3·day¿1-wastewater treatment plant influent flow rate was simulated jointly with a membrane contactor plant to evaluate the minimum costs of optimum operating conditions of membrane contactors (pH, feed flow rate and membrane surface). The optimum conditions for treating 600 m3·day¿1 of reject water was found to be 10 pH, 0.08 m3·s¿1 feed flow…
On the Reduction of Power Consumption in Vortexing Unbaffled Bioslurry Reactors
2020
Bioremediation of polluted soils via bioslurry reactors is an interesting option among those available nowadays, especially when recalcitrant pollutants are present. Vortexing unbaffled stirred tanks may be a valuable choice to this purpose as they were recently found to be more efficient than baffled vessels for solid suspension processes where mixing time is not a controlling factor. When operated at sufficiently high agitation speeds, the central vortex bottom reaches the impeller and air bubbles start to be distributed throughout the system, thus avoiding any sparger and related clogging issues. In the present work, a vortexing unbaffled stirred tank with solid loadings ranging from 2.5…
Reverse electrodialysis with saline waters and concentrated brines: A laboratory investigation towards technology scale-up
2015
Abstract The use of concentrated brines and brackish water as feed solutions in reverse electrodialysis represents a valuable alternative to the use of river/sea water, allowing the enhancement of power output through the increase of driving force and reduction of internal stack resistance. Apart from a number of theoretical works, very few experimental investigations have been performed so far to explore this possibility. In the present work, two RED units of different size were tested using artificial saline solutions. The effects of feed concentration, temperature and flowrate on process performance parameters were analysed, adopting two different sets of membranes. These experiments all…
Electrodialysis with Bipolar Membranes for the Sustainable Production of Chemicals from Seawater Brines at Pilot Plant Scale
2023
Environmental concerns regarding the disposal of seawater reverse osmosis brines require the development of new valorization strategies. Electrodialysis with bipolar membrane (EDBM) technology enables the production of acid and base from a salty waste stream. In this study, an EDBM pilot plant with a membrane area of 19.2 m2 was tested. This total membrane area results much larger (i.e., more than 16 times larger) than those reported in the literature so far for the production of HCl and NaOH aqueous solutions, starting from NaCl brines. The pilot unit was tested both in continuous and discontinuous operation modes, at different current densities (200-500 A m-2). Particularly, three differe…
Ultrasound assisted method to increase soluble chemical oxygen demand (SCOD) of sewage sludge for digestion
2004
The aim of this study was to clarify the possibilities to increase the amount of soluble chemical oxygen demand (SCOD) and methane production of sludge using ultrasound technologies with and without oxidising agents. The study was done using multivariate data analyses. The most important factors affected were discovered. Ultrasonically assisted disintegration increased clearly the amount of SCOD of sludge. Also more methane was produced from treated sludge in anaerobic batch assays compared to the sludge with no ultrasonic treatment. Multivariate data analysis showed that ultrasonic power, dry solid content of sludge (DS), sludge temperature and ultrasonic treatment time have the most signi…
Tensions and Paradoxes of Scaling Up : A Critical Reflection on Physical Activity Promotion
2022
Background: Achieving system-level, sustainable ‘scale-up’ of interventions is the epitome of successful translation of evidence-based approaches in population health. In physical activity promotion, few evidence-based interventions reach implementation at scale or become embedded within systems for sustainable health impact. This is despite the vast published literature describing efficacy studies of small-scale physical activity interventions. Research into physical activity scale-up (through case-study analysis; evaluations of scale-up processes in implementation trials; and mapping the processes, strategies, and principles for scale-up) has identified barriers and facilitato…