Jet Loop Reactor Research Articles

Down flow jet-loop reactor with NF-RO membrane system for the treatment of textile wastewater

Textile industries are significant consumers of fresh water, extensively using it for washing and dyeing processes. The effluent from these operations contains various chemicals, including complex synthetic dyes, NaCl and Na2SO4 necessitating efficient treatment before discharge into water bodies. Zero Liquid Discharge (ZLD) technology facilitates complete water recovery but leads to substantial solid waste accumulation, which poses challenges for reutilization. This study introduces an innovative approach using a Downflow Jet Loop Reactor combined with ozone and activated carbon to effectively remove color and Chemical Oxygen Demand (COD) from textile effluent. Furthermore, a combination of Nanofiltration (NF) and Reverse Osmosis (RO) membrane systems ensures comprehensive purification by effectively separating inorganic salts. Experimental results demonstrated a maximum color removal of 81.25 % from the textile effluent. The fabricated PSF/PVDF NF membrane exhibited exceptional capacity for rejecting divalent salts. Additionally, the RO reject, which is a concentrated solution of salts and contaminants, was successfully reused in a dye bath for cotton fabric dyeing. This approach highlights the practicality, sustainability, and resource conservation potential within the textile production cycle. It underscores the importance of a comprehensive water treatment strategy for achieving sustainable textile production.

Research on Ammonium Removal from Wastewater by Adsorption and Ozonation Processes

With the ongoing amendment of the European Union legislation on the treatment of municipal wastewater, stricter requirements for the removal of pollutants are expected, which calls for the need for innovative wastewater treatment technologies. Our research was focused on the removal of ammonium nitrogen from municipal wastewater by nontraditional processes based on the use of adsorption processes on zeolite (ZEO) and ozone. Adsorption, adsorption-regeneration, and adsorptive ozonation processes were applied. All processes were carried out in a completely stirred reactor (CSR) and a jet-loop reactor (JLR) with external recirculation of the reaction mixture. Experimental measurements were carried out with real municipal wastewater after mechanical treatment. The best results were achieved in the adsorption-regeneration process, which was implemented in a current loop reactor. An average ammonium nitrogen removal efficiency of 53.1% was obtained by adjusting the pH value to 10.0. Average values of 46.2% and 49.2% for chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies are an added value of the process. The values of ammonium nitrogen, COD, and TOC removal efficiencies in individual cycles confirm the high stability of the process.

Removal of methylene blue and Congo red from the wastewater in a jet loop reactor using ozone and activated carbon

The textile industry consumes a large amount of fresh water, resulting in colored effluent due to the incomplete fixation of certain dyes. Traditional textile wastewater treatment such as coagulation-flocculation, membrane filtration, thermal separation and electrochemical processes are expensive and pose significant environmental challenges. To address these issues an alternative technique for decolorizing textile effluent using a modified sparged loop reactor was proposed in this study. The jet loop reactor basically a multiphase reactor was utilized to treat textile wastewater with ozone. In this study, the textile wastewater containing water-soluble basic dyes such as Methylene blue and Congo red was simulated at a concentration of 50 ppm and the color removal efficiency of the reactor was analyzed. The effect of process parameters such as effluent flow rate (0.2– 0.4 Liter/min), sparger openings (2−4), adsorbent weight (0.5 – 1.5 g) and ozone dosage time (10–30 min) on the decolorization efficiency of the reactor were examined and optimized using Response Surface Methodology. In this study, a maximum color removal of 93 % and 85 % for Congo red dye and Methylene blue dye simulated wastewater was achieved. A correlation was developed using Response Surface Methodology-Box Behnken Design and the developed model was successfully interpreted with experimental values. Based on our results, we believe that it is possible to replace the energy-intensive thermal separation process with jet loop sparged reactor to treat the textile effluent. As a sustainable process, loop reactor may result in a huge reduction of freshwater consumption.

Investigation of Mass Transfer of Ozone in Jet Loop Reactor

Investigation of Mass Transfer of Ozone in Jet Loop Reactor

CO2-assisted hydration of propylene oxide to produce propylene glycol: Accessing high selectivity using a jet loop reactor

The synthesis of glycols from the CO2-assisted hydration of epoxides is highly significant in terms of both CO2 utilization and the production of fine chemicals. Significant effort has been devoted to designing effective catalysts. However, the gas–liquid mass transfer of this process, which is critical for the efficiency of the transformation, has received less attention. In this study, propylene glycol (PG) was synthesized with high efficiency through the CO2-assisted hydration of propylene oxide (PO) using a jet loop reactor (JLR). A systemic investigation of the influence of the reaction conditions was carried out with respect to reaction temperature, CO2 pressure, and catalyst concentration. Under optimal reaction conditions, the CO2-assisted hydration of PO proceeded efficiently with a low H2O:PO molar ratio of 1:1, producing PG with a high selectivity of 99% and full conversion of PO. Notably, the JLR exhibited higher efficiency and product selectivity than a stirred-tank reactor, demonstrating its superior advantage in facilitating gas–liquid mass transfer.

Numerical simulation of the hydrodynamics in a novel jet loop bubble column with helical sieve tapes

Hydrodynamics and mixing in a novel down-flow jet loop reactor (DFJLR) with an internal helical sieve tape (HST) were studied by computational fluid dynamics (CFD) simulations. A helical sieve tape inside the draft tube caused a significant portion of the gas bubbles to flow helically, which increased radial mixing, overall gas holdup, axial liquid velocity, and turbulent kinetic energy. Compared with a similar reactor without a helical sieve tape, the gas holdup in reactors with a helical tape or a helical sieve tape inside the draft tube was increased, respectively, by 50 % and 75 %. A helical sieve tape with an area ratio of 27 % and helical pitch length of 492 mm was efficient in increasing gas holdup while keeping a lower pressure drop. Data and designs presented in this work will give insight and further understanding for reactor scale-up as a function of geometry and flow patterns for industrial applications.

Water spray reactor for ammonia removal via air stripping: An evaluation on mass transfer and process efficiency

This paper offers a technical assessment of a developed reactor for ammonia removal via air stripping method. Optimum operational conditions were determined by experimenting numerous major parameters such as water flow, air flow, initial TAN (Total Ammonia Nitrogen) concentrations, pH, and orifice diameter of nozzles. It was found that water flow of 10 L/min, air flow rate at 120 L/min, and pH 11 were of significant parameters that facilitated higher ammonia removal efficiency up to 99 % after 7 h of experimental run with KLa = 0.0114 min-1. Empirical mathematical expression generated by employing Buckingham’s π theorem was shown to be a good fit (R2 = 0.992) to identify the relationship among Reynolds number, Weber number, and mass transfer coefficient KLa. Our newly developed reactor demonstrated satisfying performance with relatively lower air consumption (2016 L air/L liquid) compared to that of jet loop reactor (2266 L air/L liquid) and water-sparged aerocyclone (2394 L air/L liquid). The future development of this air stripping device is propitious since our reactor also enables advantages e.g., adjustable input volume and simple maintenance from scaling and fouling.

Scale-Up Strategies of Jet Loop Reactors for the Intensification of Mass Transfer Limited Reactions

For the purpose of the intensification of an industrial-scale gas-liquid process, the implementation in an alternative reactor concept is investigated at Hamburg University of Technology (TUHH) in cooperation with Ehrfeld Mikrotechnik GmbH. Existing process operation data from a bubble column hint at a mass transfer limitation of the gas-liquid reaction. In the project, a jet loop reactor (JLR) is chosen to increase the specific interfacial area between gas and liquid, and thus increase mass transfer, while keeping the reactor system mechanically simple and low-maintenance. For the investigation, a laboratory scale reactor has been designed on the basis of an existing industrial scale process and scaled according to a pilot scale reactor available at TUHH. For scaling, geometric similarity is desired, while specific energy dissipation rate and volumetric gas input are kept constant for the chosen scale-up strategy. Between the two different scales, the reactors are successfully characterised in a water-air system with regards to the important mass transfer, among other parameters. A pressure- and chemical-resistant twin of the laboratory-scale reactor is provided to the project partner for trials under real process conditions with the original material system. The presented work shows that the JLR concept can be transferred sufficiently well between different scales when suitable parameters are chosen, and offers a wide operating window. The investigations aim to provide a basis for a future scale-up of the chemical process in the JLR system to the industrial scale.

Model-Based Investigation of the Interaction of Gas-Consuming Reactions and Internal Circulation Flow within Jet Loop Reactors

Jet loop reactors are standard multiphase reactors used in chemical, biological and environmental processes. The strong liquid jet provided by a nozzle enforces both internal circulation of liquid and gas as well as entrainment and dispersion of the gas phase. We present a one-dimensional compartment model based on a momentum balance that describes the internal circulation of gas and liquid phase in the jet loop reactor. This model considers the influence of local variations of the gas volume fraction on the internal circulation. These local variations can be caused by coalescence of gas bubbles, additional gas-feeding points and gas consumption or production. In this work, we applied the model to study the influence of a gas-consuming reaction on the internal circulation. In a comprehensive sensitivity analysis, the interaction of different parameters such as rate of reaction, power input through the nozzle, gas holdup, reactor geometry, and circulation rate were investigated. The results show that gas consumption can have a significant impact on internal circulation. Industrially relevant operating conditions have even been found where the internal circulation comes to a complete standstill.

Removal of methanol vapors in a jet-loop bioscrubber equipped with a venturi injector

A jet loop reactor equipped with a Venturi injector was used as a bioscrubber to treat air polluted with methanol. The oxygen transfer coefficient of the reactor was first characterized under abiotic conditions at different volumetric power inputs, ionic strengths and dynamic viscosities. The oxygen transfer coefficient (KLa) ranged 46.9–1272.82 h−1 with an actual volumetric power inputs from 3.6 to 21.5 kW m−3. Then, the reactor was inoculated with a mixed culture and applied for the treatment of air artificially polluted by methanol. Over 91 days, the actual volumetric power input was maintained at 11 kW m−3 and the KLa ranged from 720 to 860 h−1, while the volumetric loading rate was increased from of 5–60 g L−1 d−1 and the hydraulic residence time was increased from of 12–96 h. The volumetric methanol removal rate reached a maximum of 40.75 g L−1 d−1, at a removal efficiency of 67.6%. Under the optimal conditions tested, the microbial growth yield reached a minimum value of 0.11 g COD g−1 COD. These results suggest that high efficiency reactors such as the Venturi jet loop tested in the present work allow to reach high volumetric removal rates while maintaining low growth yield.

Investigation on gas induction of liquid–gas ejector in jet loop reactor

Abstract Liquid–gas ejector as a key component of jet loop reactor (JLR), plays an important role in the continuous production of gas–liquid mixing reaction. In this paper, a formula for estimating the gas induction of the ejector is presented. The effects of nozzle radius and mixing length on gas induction of liquid–gas ejector for gas–liquid mixing are simulated, and the formula is verified. Focusing on the efficiency and gas induction, the geometrical parameters are analyzed for the same cases, so that the performance of the ejector can be thoroughly understood. The results show that the optimum mixing section length to diameter ratio (LDR) is about 5–7, and the decrease of nozzle outlet radius can increase the gas induction, which provides a reference for the evaluation of gas induction for liquid–gas ejector and has crucial guiding significance for the design of nozzle and mixing section of liquid–gas ejector in industry.

An effective synthesis of bio-based pentamethylene diisocyanate in a jet loop reactor

A highly efficient jet loop reactor (JLR) with a submerged nozzle was developed to enhance the mixing and dispersion capacity of a phosgenation reaction, which was implemented in the preparation of pentamethylene diisocyanate (PDI). Model test of air–water two-phase flow was carried out first, which provided references for the control conditions of the phosgenation of 1,5-pentanediamine (PDA). Carbon dioxide (CO2) was used to protect PDA as 1,5-pentanediamine carbonate (PDAC). Both the carbonate-forming and phosgenation reactions were preferably carried out in the JLR. The phosgene inlet pressure, asynchronous speed of the circulating pump, PDI content, and reaction completion time in the JLR system were investigated. Interestingly, we found that the PDI content exceeded 0.6–0.7%, the yields of PDI exceeded 7–8.5%, and the reaction time was decreased by approximately 50% compared to that of the traditional stirred-tank reactor (STR). The JLR is thus applicable for the preparation of PDI and is superior to the STR system.

Ammonia stripping using a continuous flow jet loop reactor: mass transfer of ammonia and effect on stripping performance of influent ammonia concentration, hydraulic retention time, temperature, and air flow rate.

When wastewater containing ammonia is discharged into the receiving environment without any kind of treatment, it causes both environmental problems and negatively affects human health. In this study, the aim was to strip ammonia using air in a continuous flow jet loop reactor (JLR) and investigate the effects of ammonia concentration, hydraulic retention time (HRT), air flow rate, and temperature on ammonia removal within this scope. By changing the ammonia concentration in the influent, no significant change was observed in ammonia removal efficiency. With air flow rate 45 L min-1, temperature 50 °C, pH 11, and HRT 7.5 h, mean 88.1% ammonia removal was achieved. Increasing the HRT, air flow rate, and temperature increased the ammonia removal efficiency. Later the ammonia stripping process in the continuous flow JLR was modeled and the volumetric mass transfer coefficient (KLa) for each parameter was calculated from the model equation. While the experimental parameters of air flow rate and temperature had a significant effect on the mass transfer coefficient, influent ammonia concentration and HRT were determined to have no effect.

Improvement of biotreatability of environmentally persistent antibiotic Tiamulin by O3 and O3/H2O2 oxidation processes

ABSTRACT The aim of the work was to assess the efficiency of ozonation and ozonation in combination with H2O2 in jet loop reactor to increase biotreatability of persistent veterinary antibiotic Tiamulin. The efficiency of oxidative processes was monitored by combined approach based on determination of efficiency of wastewater treatment and impact to waste sludge stabilization. Degradation of Tiamulin in model wastewater (100 mg L−1) during oxidation was followed by COD and DOC measurements while changes in biodegradability were determined by respirometric measurements. Biogas production potential was also determined to identify problems related to anaerobic digestion of waste sludge resulted in treatment of Tiamulin-contaminated wastewater. At ozone dose of 69 gozone gCOD −1 and 220 gozone gDOC −1removal for COD and DOC was 26% and 17%, respectively. Better biotreatability was confirmed by respirometric testing. H2O2 addition did not improve removal efficiency (11–13%). The second stage of nitrification was suppressed by the addition of Tiamulin and ozonation again recovered formation. O3/H2O2 treated sample reduced the nitrification, especially formation of in the first phase of the process. Simultaneously, quadratic model was developed to describe the relationship between oxygen uptake rate and changes in ammonium nitrogen concentration due to the oxidative treatment. The positive impact of ozone was also confirmed by ozonation of Tiamulin-contaminated (400 mg L−1) waste sludge where biogas production potential was increased for 6-times. Combination of approaches confirmed, that O3 effectively increase the treatability of Tiamulin in wastewater and sludge while addition of the hydrogen peroxide generally did not improve the performance of the processes.

Comparison of jet loop and trickle-bed reactor performance in large-scale exploitation of glucose reductive aminolysis

Commercial scale jet-loop and trickle bed reactor simulations have been performed for the reductive aminolysis of glucose with dimethylamine (DMA) in combination with an experimental assessment in a (large) lab-scale fed-batch and trickle bed reactor. Based on the intrinsic kinetics of the sequence of homogeneous and heterogeneously catalyzed reaction steps in the reductive aminolysis reaction network, coupled with a different flow pattern and catalyst-to-liquid ratio, significant differences in the yield of N,N,N’,N’-tetramethylethylenediamine (TMEDA) and N,N-dimethylaminoethanol (DMAE) can be expected for both reactor types. Yet, TMEDA is obtained in the highest yields irrespective of the reactor type. In the jet-loop reactor, which is operated overall as a batch reactor, an optimized TMEDA yield up to 57 % is simulated, while a non-negligible yield of DMAE, up to 12 %, is also achieved. The optimized operating conditions are such that they correspond to the high DMA to glucose ratio used during lab-scale fed-batch experimentations, also explaining why the jet-loop product spectrum is almost identical to the latter. This is ensured by the efficient heat-exchange in the jet-loop reactor, which is, in contrast, one of the main bottlenecks for exploitation of the reductive aminolysis in a trickle bed reactor. The second challenge to address in the trickle bed reactor is the limited extent of hydrogen transfer from gas to liquid, which can only be partially overcome by increasing the feed flow rates. While isothermal operation indicates TMEDA yields of about 60 %, non-isothermally simulated TMEDA yields only amount to 40 %. The latter yield loss was also validated experimentally in the trickle bed reactor and confirmed that avoiding degradation reactions remains challenging as it is critical in the reductive aminolysis of glucose.

Treatment of acid mine drainage with coal fly ash in a jet loop reactor pilot plant

A 1500 L batch jet loop reactor pilot plant was designed, constructed, and evaluated for performance in the treatment of acid mine drainage (AMD) using coal fly ash with a view to optimize its operation and generate performance data. Results showed that concentration of major contaminants (sulfate, Al, Fe, Ca, Mg), and minor contaminants in the treated AMD can be significantly lowered (between one and four orders of magnitude) compared to the raw AMD. It was shown that the one-step treatment process recovered at least 66.6% (728.56 kg) of treated water depending on the degree of dewatering required for slurry pumping. The energy consumption of 2.655 kW used for pumping indicated that an oversized centrifugal pump (15 kW capacity) was used for the neutralization cycle, as only a small fraction of the pump capacity was utilized. The treated water met the target water quality range (TWQR) limit for agricultural irrigation in South Africa. The analysis of the solid residue shows its suitability for backfilling of mine voids or for making geopolymer such that AMD treatment with fly ash results in a zero discharge process. The treatment process offers a cradle-to-cradle solution to acid mine drainage and coal fly ash.

Comparison of phenol removal with ozonation in jet loop reactor and bubble column

This study aimed to remove phenol with ozonation in a jet loop reactor (JLR) and a bubble column (BC). In the first stage of the study, the mass transfer properties of JLR were determined and superiority over BC reactors were shown, and in the second stage, these reactors were used in phenol removal studies. At the same conditions, the volumetric mass transfer coefficient of JLR was 0.540 min-1, while this value was determined as 0.246 min-1 in the BC reactor. In phenol removal, the effects of initial phenol concentration, ozone dosage and pH on phenol and chemical oxygen demand (COD) removal were determined for both JLR and BC. While the pseudo-first rate constant for phenol removal in JLR at 221 mg/min ozone dosage was 0.1756 min-1, this value was only calculated as 0.1157 min-1 in the BC reactor. As a result, it has been shown that JLRs can achieve higher ozone gas transfer with lower energy consumption and perform more effective phenol and COD removal than BC reactors, especially at low pH and high ozone dosages.

Design of a Novel Membrane Draft Tube Jet Loop Reactor (MDJLR) and Treatment of Slaughterhouse Wastewater.

The most important obstacle to the widespread use of membrane bioreactors (MBRs) is membrane fouling. In this study, a high-efficiency compact MBR was developed. Therefore, the draft tube of the jet loop reactor (JLB) was planned for use as a membrane module. The high-velocity jet streams, which are present according to the nature of the JLBs, provide high crossflow (cut-off force) on the membrane surface. Thus, the produced membrane module is operated in submerged membrane mode. This enhanced JLB modification is named the membrane draft tube jet loop reactor (MDJLR). This new system has a KLa value of 139 h−1 (at E/V of 2.24 kW m−3). In the next stage, treatment of slaughterhouse wastewater with the MDJLR was carried out. Under the 5.5 kg COD m−3 d−1 loading rate, efficiencies over 97% were achieved. The system operated continuously for 50 days without membrane backwashing or cleaning. During this period, fluxes of 3 L m−2·h−1 were approximately obtained at operating conditions of 850 mg L−1 MLSS (mixed liquor suspended solids) concentration, 1 bar suction pressure (∆P), and 3000 L h−1 circulation rate. This developed MDJLR will make jet loop membrane bioreactors (JLMBRs) and MBRs more compact and improve their performance.

Experimental Study on Bubble Size Distribution in Gas-Liquid Reversed Jet Loop Reactor

Abstract Bubble size distribution (BSD) is important for gas-liquid jet loop reactor (JLR)’s mass transfer performance of inter-phases. A self-designed reversed JLR was investigated with air-water system on the BSD. The CCD camera of particle imaging velocimetry (PIV) system and image processing technique were used to obtain the reliable photo. The influences of four parameters, gas phase flow rate, liquid phase flow rate, draft tube diameter and ejector mounting position, on the BSD were studied in detail. The results showed that the local BSD is accordance with log-normal distribution under the experimental conditions and the average diameter and BSD range increase with the increase of the gas phase flow rate, and decrease with the increase of the liquid phase flow rate, the downward movement of the nozzle installation position and the increase of the diameter of the draft tube.

Experimental investigation on multiscale hydrodynamics in a novel gas–Liquid–Solid three phase jet‐Loop reactor

Multiphase flow hydrodynamics in a novel gas–liquid–solid jet‐loop reactor (JLR) were experimentally investigated at the macroscales and mesoscales. The chord length distribution was measured by an optical fiber probe and transformed for bubble size distribution through the maximum entropy method. The impacts of key operating conditions (superficial gas and liquid velocity, solid loading) on hydrodynamics at different axial and radial locations were comprehensively investigated. JLR was found to have good solid suspension ability owing to the internal circulation of bubbles and liquid flow. The gas holdup, axial liquid velocity, and bubble velocity increase with gas velocity, while liquid velocity has little influence on them. Compared with the gas–liquid JLRs, solids decrease the gas holdup and liquid circulation, reduces the bubble velocity and delays the flow development due to the enhanced interaction between bubbles and particles (Stokes number >1). This work also provides a benchmark data for computational fluid dynamics (CFD) model validation. © 2019 American Institute of Chemical Engineers AIChE J, 65: e16537, 2019