Application of Calcium-rich Clay Mineral Under Nonwoven Fabric Mats and Sand Armor as Cap Layer for Interrupting N and P Release from River Sediments

This work investigates the applicability of thermally treated calcium-rich clay minerals (CRCMs), such as sepiolite (SPL), attapulgite (ATT), and dolomite (DLM) to hinder the nitrogen (N) and phosphorus (P) release from river sediments. A non-woven fabric mat (NWFM) or a sand layer were also capped as armor layers, i.e., placed over CRCMs to investigate the capping impact on the N/P release. The capping efficiency was evaluated in a cylindrical reactor, consisting of CRCMs, armor layers, sediments, and sampled water. We monitored N/P concentrations, dissolved oxygen (DO), oxidation reduction potential, pH, and electric conductivity in overlying water over 70 days. The DO concentrations in the uncapped and capped conditions were preserved for 30 days and 70 days (until the end of experiment duration), respectively. ATT showed higher efficiency for NH4-N and T-N than the other two materials, and the capping efficiency of NH4-N was measured as 96.4%, 93.7%, and 61.6% when capped with 2 cm sand layer, 1 cm sand layer, and NWFM layer, respectively. DLM showed a superior rejection capability of PO4-P to ATT and SPL, reported as 97.2% when capped with 2 cm sand armor. The content of weakly adsorbed-P was lower in the uncapped condition than in the capping condition. It can be concluded that ATT and DLM can be used as capping agents to deactivate N and P, respectively, to reduce water contamination from sediments of the eutrophic river.

Plasma and electrical characteristics depending on an antenna position in an inductively coupled plasma with a passive resonant antenna

We investigated the plasma and electrical characteristics depending on the antenna position in an inductively coupled plasma with a passive resonant antenna. When the powered antenna and passive resonant antenna are installed near the top plate and in the middle of the cylindrical reactor (Setup A), respectively, the ion density at the resonance is about 2.4 times to 9 times higher than that at non-resonance. This is explained by the reduction in power loss in the powered antenna (including the matching circuits) and the increase in power absorbed by the plasma discharge. However, when the powered antenna and passive resonant antenna are interchanged (Setup B), the ion density at the resonance is not significantly different from that at the non-resonance. When RF power is changed from 50 W to 200 W, the ion density at the resonance of Setup B is 1.6 times to 5.4 times higher than at the non-resonance of Setup A. To analyse this difference, the profile of the z-axis ion density is measured and the electric and magnetic field simulations are investigated. The results are discussed along with the electron kinetics effect and the coupling loss between the antenna and the metal plate.

The Exhaust Emission Characteristics of a Spark-Ignition Engine Fuelled with Gasoline and Synthesized Biogas from Non-Thermal Plasma

This study synthesizes biogas with low methane contents (<50%) to hydrocarbons that form a combustible synthesis gas (syngas) mixture. Conventional methods used for reforming biogas has limitations in terms of fabrication, maintenance, and cost. This is especially true when the biogas’ composition fluctuates. Non-thermal plasma (NTP) is an alternative method to produce combustible syngas for power generation. Thus, the exhaust emissions from a 2 kWe spark ignition (SI) engine fuelled with gasoline and NTP-synthesized biogas is investigated with respect to the type of NTP reactor, plasma power consumption and biogas composition. Two types of NTP reactors are used: a cylindrical reactor where the gas flow path is linear, and a cyclonic reactor where the gas flow path is a curvature, similar to that of a gas-solid cyclone separator. The results show that the NTP reactors produced additional hydrocarbons, decreasing flue gas temperatures by 4°C and reducing NOx emissions by 35%.

Pretreatment and Bioprocess Trials in Various Reactor System on Lignocellulosic Biomass for Cellulosic Biomaterials

Pretreatment on lignocellulosic biomass prior to extraction of biomaterials, degradation of bioproduct, or production of biomaterial/bioproduct/biofuel, crucially influences the intended outcomes. The pretreatment of oil palm fronds (OPF), one of the most abundant agriculture residues in Malaysia, can be conducted based on the need of the methodology, either for small, lab, pilot, or industrial scales. In this article, examples of reactors for the pretreatment for instance microreactor (Bioshake iQ), conical shake flask, and mini-cylindrical reactor scale (fabricated) as well as the monitoring bioreactor (BlueSens Monitoring GmbH) reactor system dedicated for fermentation process using the outcome material from pretreatment process, are presented. All pretreatment trials with ionic liquid (IL) of 1-ethyl-3-methylimidazolium acetate [EMIM]Ac on OPF were conducted with a scaling-up strategy from micro-to-macro to fabricated reactors, monitoring Crystallinity Index (CrI) and Lateral Order Index (LOI). Electron beam irradiation pretreatment using 1000kGy was also tested in macroscale mode for CrI and LOI. Effectiveness of approximately 23 to 37% of CrI via microreactor experiments using 50, 70, and 90% v/v of [EMIM]Ac and at a temperature of 99oC was observed. Higher concentration of IL and temperature with nearly insignificance of solid loading of OPF in reaction liquid to the increase of the amorphous level of OPF was reported by macroscale mode in the 570-mL fabricated reactor. A short oxygen uptake rate (OUR) phase was observed in a 500-mL BlueSens shake flask with the real-time monitoring systems for 45-mL working volume, a nearly 10% of the total reactor volume for saccharification-fermentation using Escherichia coli K011 ATCC 55124 on approximately 2.22% w/v pretreated OPF from macroscale mode. Various data examples from these micro-to-macro scales including in a fabricated reactor system mode are crucially needed for further observations prior to pilot or industrial scales, needing a systematic data collection to be simulated and investigated in the future.

Evaluation for the Production of Bio-Carbon and Bio-Oil through a Combined Process of Gasification and Slow Pyrolysis of the Organic Waste Fraction

The management of vast amounts of urban solid waste is daily. The population growth must create diligent politics that mitigate the impacts created by the increased demand for energy and basic needs. This research aimed to analyze biocarbon and bio-oil production performance through the combination of gasification and slow pyrolysis using a cylindrical reactor with a fixed bed. The residues were collected from the market square of “La Satélite” located in Florencia-Caquetá, and the organic fraction was separated without any previous treatment. For this, an experimental design was randomly created with two factors: 6 work temperatures for the reactor (150, 250, 350, 450, 550, 600°C) and three samples of residues (5, 10 and 15 kg), for a total of 18 treatments and three repetitions. The results were analyzed through analysis of variance (ANOVA), obtaining the highest biomass production with 150°C and 15kg of residue and the highest amount of bio-oil with the combination of 5kg of residue with 150°C. The results demonstrate that combining these two thermochemical processes (gasification and slow pyrolysis) is an efficient and sustainable way to treat solid residues that should be implemented on a large scale.

Experiments and Computational Research of Biomass Pyrolysis in a Cylindrical Reactor

The article features an experimental study of thermally thin biomass samples (beech wood particles 17×8×6 mm) pyrolysis in a laboratory scale batch reactor. The reactor was a cylindrical steel body with internal diameter of 200 mm and height of 500 mm. The temperature of a lateral surface of the cylinder during the experiment was being kept constant (550 °C) due to electrical heating. The initial loading of the apparatus was about 4 kg with moisture content of about 14 % by weight. During the experiment, the temperature values of the material being pyrolyzed were recorded at two points of the radial coordinate, viz. at the wall of the apparatus and on its axis. A one-dimensional numerical model of the nonstationary process of biomass conversion (heat and mass transfer in combination with the Avrami – Erofeev reaction model) has been proposed and verified. The reactor is represented as a set of a countable number of cylindrical layers, considered as cells (representative meso-volumes) with an ideal mixing of the properties inside. The cylindrical surfaces that form cells are considered to be isothermal. The size of the cells is chosen to be sufficiently large in comparison with the individual particles of the layer, which makes it possible to consider the temperature field inside the cell volume as monotonic. The evolution of the temperature distribution over the radius of a cylindrical reactor is determined on the basis of a difference approximation of the process of non-stationary thermal conductivity. The calculated forecasts and experimental data showed a good agreement, which indicates the adequacy of the developed mathematical model of pyrolysis and makes it possible to recommend it for engineering calculations of biomass pyrolysis. This model can also be useful in improving the understanding of the basic physical and chemical processes occurring in the conditions of biomass pyrolysis.

Application of the model of cylindrical reactor for self-purification by indigenous microorganisms

Pharmaceutically Active Compounds (PhACs), in particular, Nonsteroidal anti-inflammatory drugs (NSAIDs) are in increasingly wider usage, and as such are more and more frequently part of the organic matter of recipient rivers, especially in their lower course. To indicate their significance as pollutants, as well as the significant role that the presence of autochthonous microflora plays in solving this issue, we undertook to perform this experiment. The experiment, titled ?Application of the Model of Cylindrical Reactor In Self-purification by Indigenous Microorganisms?, was conducted during one year period at the location of Vukovci, in the lower course of Moraca river. Assuming that the concentration of NSAIDs and PhACs in water can be reduced through self-purification, it has been proven that such processes result in a modification of phenotype in the indigenous microbiological population. Having the abovementioned premise in mind, we constructed the experiment model, which entails kineticism of water, whereas the defined volume flow rate per unit time was 0.005 m/s; through the known distance of 432 m. Over one year of application of the model of the cylindrical reactor for enhancing self-purification capacity by indigenous microorganisms, auto-purification increased by 28.05%, the phenotype of the indigenous microorganisms changed by 24.62%, whereas the total concentration of particular PhACs, micropollutants, and NSAIDs decreased by 4.19%.

Colloidal sulphur production by electrochemical oxidation of sulphide in a swirling flow reactor

A cylindrical reactor with swirling flow is tested for the production of colloidal sulphur via the oxidation of sulphide ions with a concentration of 2 g dm−3 in alkaline solutions...