Bench-scale Device Research Articles

Performance of novel carbonate-based CO2 post-combustion capture process

A novel carbonate-based CO2 capture process was developed at VTT, and proof-of-concept was tested using a bench scale device. The process has closed-loop, carbonate liquid, and the captured CO2 is released at under-pressure. The temperature is around 65 °C, which enables, for example, utilisation of waste heat streams in process integrations. The process performance and its parameters were tested using 8 w-% sodium carbonate liquid with simulated gases, real flue gases and biogas. Also, the absorption mass transfer kinetics and suitable flow parameters of the invented microbubble generator were assessed. The device has successfully and continuously run for tens of hours, and the typical CO2 capture rate between 72 and 84 % were performed at the liquid pH value of 9.3, using a near-atmospheric pressure process. Mass transfer rates kLa for carbonate liquid and air were between 0.14 and 0.34 s−1, which indicates efficient gas absorption, enabling size reduction of the device size.

Study on ex-situ catalytic pyrolysis of poplar to produce aromatics over a dual-catalyst system of hydroxyapatite and HZSM-5

The ex-situ catalytic pyrolysis of poplar in a dual-catalyst system of hydroxyapatite (HAP) and HZSM-5 was performed using a bench-scale device to enhance the aromatics production. Results indicated that the introduction of HAP could effectively achieve the deoxygenation of macromolecular oxygenates, which were then converted into hydrocarbon precursors. The combination of HAP and HZSM-5 exceedingly promoted the production of aromatics especially monocyclic aromatics (MAHs) than single HZSM-5. The effects of operating conditions on aromatics yield and distribution were investigated. Under the catalyst layout of mode B, with the optimum conditions reaching the catalytic temperature of 500 °C, HAP to HZSM-5 ratio of 2:4, and catalyst to biomass ratio of 1:1, the maximum aromatics yield of 9.10 wt% was achieved, accompanied by the monocyclic aromatics/polycyclic aromatics ratio enhanced to 2.33. At this point, the synergistic effect for MAHs and total aromatics reached 170.09% and 214.14%, respectively. Compared to the conventional metal oxides, the HAP/HZSM-5 dual-catalyst system exhibited superior performance in aromatics production. Besides, the anti-coking capability of HZSM-5 in the dual-catalyst system was also better than that of pure HZSM-5. This research provided a new perspective for the efficient utilization of biomass energy.

Enhancing wound healing efficiency with fractionated Schinus molle essential oils

The study focused on the extraction of essential oils from Schinus molle L. seeds using a novel pulsed steam distillation method, followed by fractionation to create an anti-inflammatory topical pharmaceutical product. This formulated product was unexpectedly employed in a specific case where an individual suffered a deep wound on the forehead due to an accident involving a sharp metal object, resulting in excessive bleeding. The oily product was directly applied to the wound, yielding remarkable outcomes. Notably, the bleeding stopped almost immediately, and the patient experienced an astonishingly rapid recovery, with complete closure of the wound observed within just five days. This remarkable healing time amounted to only a fifth of the expected duration for similar cases. The study highlights the significance of the extraction and fractionation processes, which were carried out using bench-scale devices, and underscores the importance of analyzing the chemical composition of the essential oils using gas chromatography coupled with mass spectrometry. These findings emphasize the critical role played by the pulsed steam distillation method and the formulation of the product in achieving exceptional wound healing performance

Effect of Pipe Materials on Bacterial Community, Redox Reaction, and Functional Genes

In the present study, the effect of pipe materials on water quality as well as the microbial community was researched with static devices as well as dynamic ones. Five kinds of pipe materials (SP: steel plastic composite pipe, SS: stainless steel pipe, DI: ductile iron pipe, CI: cast iron pipe, GS: galvanized steel pipe) were chosen, and the soaking experiment was carried out with bench-scale devices. To further investigate the performance of pipe materials over a long term, a pilot-scale simulated drinking water distribution system was constructed, and the water quality parameters were monitored for six months. The pipe materials were ranked as SP, DI, and CI by the order of increasing turbidity, CODMn, and NH3-N. Furthermore, the biofilm samples were analyzed via pyrosequencing and COG functional categories. The DI biofilm possessed the highest bacterial diversity with a Shannon index of 3.56, followed by SP (3.14) and CI (0.77). The presence of nitrate-reducing bacteria (NRB), iron-oxidizing bacteria (IOB), iron-reducing bacteria (IRB), and sulfate-reducing bacteria (SRB)was identified, and NRB composed the largest share in all pipe materials (13.0%–17.2%), with other redox bacteria making up a minor proportion (0.02%–1.52%). NRB and IRB inhibited the corrosion process while IOB and SRB enhanced it. Most dominant genera present in samples were derived firstly from soil or active sludge, indicating a turbidity problem due to soil contamination in the distribution network.

Electron Bernstein wave conversion of high-field side injected X-modes in QUEST

This paper presents a detailed design of the Q-shu University experimental steady state spherical tokamak’s (QUEST’s) high-field side (HFS) injection system for electron Bernstein wave (EBW) excitation and the results of an experimental comparison of the HFS eXtraordinary X-mode and low-field side (LFS) ordinary O-mode injection of 8.2 GHz radio frequency (RF) power. Waveguides, as an alternative to mirror polarizers for transmitting RF X-mode power from LFS to HFS for EBW conversion, were used instead of the installation of an RF mirror. Testing of LFS-to-HFS RF power transmission at 8.2 GHz, using an RG-50-type vacuum waveguide in a bench-scale device filled with SF6 gas at 0.03 Mpa, revealed that an RF power of 10.8 kW could traverse the fundamental electron cyclotron resonance layer for 60 s without breakdown. The short-length, open-ended waveguide antenna used in the HFS injection-induced wave diffraction reduced the efficiency of power delivery to the upper hybrid resonance (UHR) by approximately 7% at an electron temperature of 50 eV. The HFS injection was able to produce brighter camera images than the standard LFS injection. The location of the UHR, as estimated by measuring the density with an interferometer, agreed with its location as measured by plasma radiation low-field, side-edge positions shown by fast camera imaging. This indicates that the plasma was produced by mode-converted EBW. The HFS injection had an absorption efficiency of 96%, compared to 40% for LFS. A greater fluctuation of floating potential adjustable to the lower hybrid wave (LHW) was observed in the HFS case by installing a Langmuir probe, confirming that EBW conversion efficiency was higher in the HFS case. Moreover, after setting the poloidal field to BPF = 7.6 mT, plasma current (IP) in the HFS peaked at 1.3 kA, as opposed to 0.3 kA for LFS, despite LFS injection having a total power of 55 kW, compared to 40 kW for HFS. However, as the impurity level was comparatively high, it is believed that this IP is dominated by pressure-drive, which makes it difficult to analyze EBWCD. Finally, the line-integrated density in the HFS injection peaked at 1.6 × 1018 m−2, compared to 8 × 1017 m−2 in the LFS one.

Ignition delay times of live and dead pinus radiata needles

There are still many open questions related to the fire behavior of live and dead wildland fuels and their senescence process. We have physically and biochemically studied live and dead pinus radiata needles, their aging process, and their fire behavior using a systematic aging procedure which allows to characterize the evolution of the fuel moisture content and the photosynthetic pigments over time, and to determine the period of time after sample collection in which specimens can be considered to be alive. Results show that pine needles stay alive for up to 12 h after collection if they remain attached to the twigs. The influence of senescence on spontaneous ignition was tested on two bench-scale devices, the I-FIT and the SCALA, under discontinuous and continuous configurations, respectively. Live pine needles showed larger critical heat fluxes than dead needles, while dead and re-hydrated samples have increased critical heat fluxes for greater moisture contents. Experimental results were interpreted with thermal models based on a two-phase description of the fuel layer. We established a correlation of the form 1/tig∝q˙inc'' for both ignition configurations, which is adequate for engineering applications and allows the estimation of effective properties for wildland fuel beds.

Effect of biological activated carbon filter depth and backwashing process on transformation of biofilm community

The biological activated carbon (BAC) is a popular advanced water treatment to the provision of safe water supply. A bench–scale device was designed to gain a better insight into microbial diversity and community structure of BAC biofilm by using high–throughput sequencing method. Both samples of BAC biofilm (the first, third and fifth month) and water (inlet water and outlet water of carbon filter, outlet water of backwashing) were analyzed to evaluate the impact of carbon filter depth, running time and backwash process. The results showed that the microbial diversity of biofilm decreased generally with the increase of carbon filter depth and biofilm reached a steady–state at the top layer of BAC after three months’ running. Proteobacteria (71.02%–95.61%) was found to be dominant bacteria both in biofilms and water samples. As one of opportunistic pathogen, the Pseudomonas aeruginosa in the outlet water of device (1.20%) was about eight times higher than that in the inlet water of device (0.16%) at the genus level after five–month operation. To maintain the safety of drinking water, the backwash used in this test could significantly remove Sphingobacteria (from 8.69% to 5.09%, p<0.05) of carbon biofilm. After backwashing, the operational taxonomic units (OTUs) number and the Shannon index decreased significantly (p<0.05) at the bottom of carbon column and we found the Proteobacteria increased by about 10% in all biofilm samples from different filter depth. This study reveals the transformation of BAC biofilm with the impact of running time and backwashing.

Comparison of fouling of raw milk and whey protein solution on stainless steel and fluorocarbon coated surfaces: Effects on fouling performance, deposit structure and composition

Fouling from raw milk and from whey protein solutions mimicking the protein content of milk have been performed at two length scales, using a microfluidic heat transfer cell and a bench-scale device with hydraulic diameters 1.0 mm and 16.1 mm, respectively. The microfluidic cell allows raw milk to be studied in once-through mode and was used to identify polymer coated surfaces to test against stainless steel. Several of the fluorocarbon coated surfaces reduced the mass deposition but the pressure drop and thermal resistance did not match these directly, indicating that the nature and structure of the deposit is affected by the surface. A fluorinated ethylene propylene coating was identified as a promising candidate for large scale tests. At the interface with apolar surfaces, raw milk fouling layers were high in protein whereas a strongly attached mineral-rich layer was present at the interface with steel. The attraction of denatured protein towards apolar surfaces and the formation of a calcium phosphate layer on steel at later stages of fouling are explained with arguments based on the interfacial free energy of these materials in water.

Improvement of the electro-bioremediation process of a non-polar herbicide-polluted soil by means of surfactant addition

Oxyfluorfen is a non-polar herbicide that may cause severe soil pollution. The present work studies the possible improvement due to surfactant addition in the efficiency of electro-bioremediation of a clay soil polluted which such a non-polar, low-mobility pollutant. Two-week-long batch electro-bioremediation experiments were performed in a bench-scale device. Oxyfluorfen-polluted soil (20 mg kg−1) was inoculated with an acclimated microbial culture, and several experiments were performed using different surfactant concentrations in the electrode wells (0.0, 2.5, 5.0, 10.0 and 20.0 g L−1 of SDS, sodium dodecyl sulphate). Experiments were performed under 1.0 V cm−1 and electrode polarity reversal. It was observed that the electro-osmotic flow (EOF) increased with SDS concentration and that SDS was successfully distributed across the soil, probably improving the oxyfluorfen mobility. Additionally, microbiological activity was fully maintained during the experiments. Electro-bioremediation without SDS removed 14% of the oxyfluorfen, while under 2.5 g L−1 SDS, the efficiency increased to 22% because of an expected improvement in the contact between the different species in the soil. However, higher SDS concentrations (between 10.0 and 20.0 g L−1) caused a decrease in the oxyfluorfen removal efficiency, as SDS is an easily biodegradable compound and was preferably used as substrate by the microbial culture instead of oxyfluorfen. Additionally, the use of high concentrations of SDS was clearly inefficient, as high amounts of the surfactant were lost through the EOF, and even low amounts of oxyfluorfen were removed to the electrode wells, which means that ex situ treatment of the polluted water would be needed.

Dewatering of pulp and paper mill biosludge and primary sludge

Dewatering and handling of pulp and paper mill sludge is challenging and often comprises more than half of the overall wastewater treatment costs at a mill. Primary sludge is usually more dewaterable than biosludge (waste activated sludge), and the ratio between both types of sludge largely determines the dewaterability of the sludge mix. This study has quantified the benefits of adding primary sludge to biosludge to enhance the dewaterability in terms of cake solids and filtrate/pressate solids content. Furthermore, the effects of the particle size distribution and the monovalent to divalent cation ratio of the various types of sludge were investigated. Biosludge and three types of primary sludge from a Canadian pulp and paper mill were mixed at various ratios and tested for dewaterability using a Crown Press®, a bench-scale device which simulates industrial belt press dewatering. Results show that after addition of primary sludge at up to 40% mass proportion (dry solids basis) the dewatered cake solids content increased substantially, from 10.4% to 18.7–19.9%, depending on the type of primary sludge added. Further addition of primary sludge led to comparably only small improvements. Primary sludge addition also resulted in decreased total suspended solids (TSS) concentrations in the combined gravity filtrate / Crown Press pressate. Primary sludge content of only 10% in the sludge mix was sufficient to decrease the TSS concentration from 1.8 g/L to 0.2 – 0.4 g/L. The study shows that only less than half of the sludge mix needs to consist of primary sludge, in order to achieve adequate dewaterability. This opens up the possibility of retaining more primary fiber within the pulping process, without compromising downstream sludge dewatering.

Experimental study of homogeneous Hg oxidation in air and oxy-simulated flue gas

This study investigated the effects of Cl2, SO2, and NO on the mercury (Hg) speciation during oxy-combustion and compared it with the Hg speciation in air-simulated flue gas with Cl2. Experiments were conducted in a bench-scale device at 200 °C. The results of Hg oxidation in an N2 and CO2 atmosphere with Cl2 showed that CO2 indirectly restrained Hg oxidation. Oxy-simulated flue gas promoted Hg oxidation more than air-simulated flue gas promoted that, because the oxygen in oxy-simulated flue gas indirectly promoted Hg oxidation using Cl2. The percentage of Hg oxidized in both oxy-simulated flue gas and air-simulated flue gas with NO decreased as the concentration of Cl2 increased because NO restrained Hg oxidation with Cl2 through the elimination of the O and ClO radicals. SO2 inhibited Hg oxidation with Cl2 by consuming the O radicals. Moreover, when both NO and SO2 were present in oxy-simulated flue gas with Cl2, the effect of SO2 on Hg oxidation was related to the NO concentration.

Experimental demonstration and modeling of an adsorption-enhanced reverse flow reactor for the catalytic combustion of coal mine ventilation air methane

Ventilation air methane is a major contributor to the carbon footprint of the coal mining industry. This contribution can be mitigated by combustion of methane to carbon dioxide. The use of efficient combustion devices, such as catalytic reverse flow reactors, can improve the economy of the process. However, the high water content of the ventilation air can inhibit catalysts (such as palladium) used in this process. The overcome this issue a novel reverse flow reactor with integrated separation, capable of adsorbing water from the feed before reaching the catalyst, is studied. The adsorbent is regenerated in situ thanks to the characteristic thermal pattern of reverse flow reactors. The application of this reactor design to the combustion of ventilation air methane has been demonstrated in a bench-scale device, operated at 0.15m/s (n.t.p.) superficial velocity and different methane concentrations (1800–5400ppm) and switching times (100–600s). A mathematical model for this reactor has been proposed, the water adsorption parameters have been determined experimentally, and the model has been validated by comparison to bench-scale experimental results.

Selective catalytic reduction of NO in a reverse-flow reactor: Modelling and experimental validation

The abatement of nitrogen oxides produced in combustion processes and in the chemical industry requires efficient and reliable technologies capable of fulfilling strict environmental regulations. Selective catalytic reduction (SCR) with ammonia in fixed-bed (monolithic) reactors has stood out among other techniques in the last decades. In this work, the use of reverse-flow reactors, operated under the forced un-steady state generated by the periodic reversal of the flow direction, is studied for improving the SCR performance. This reactor can take advantage of ammonia adsorption in the catalyst to enhance concentration profiles in the reactor, increasing reaction rate, efficiency and reducing the emission of un-reacted ammonia. The process has been studied experimentally in a bench-scale device using a commercial monolithic catalyst. The optimum operating conditions, best ammonia feed configuration (side or central) and capacity of the reactor to deal with feed concentration disturbances is analysed. The experiments have also been used for validating a mathematical model of the reactor based on mass conservation equations, and the model has been used to design a full-size reverse-flow reactor able of operating at industrial conditions.

Experimental Study on Regularities of Carbonation for CO&lt;sub&gt;2&lt;/sub&gt; Capture Using Ammonia Solution

The regularities of carbonation in the process of CO2 capture were investigated using ammonia solution by laboratory-scale and bench-scale device. The research showed that the lower volatility of NH3 and higher rate of carbonization in solution could be achieved with ammonia concentration ranging from 10 to 16 wt%. The emission of ammonia accelerated with the increasing of flow of flue gas, and the bubbling function of air was apparent in a lower CO2 volume fraction, which has an adverse effect on carbonation of solution. Benefits of environment and economic could be achieved in CO2 capture using ammonia solution so long as appropriate ammonia concentration, the flue gas flow and volume fraction of CO2 were determined.

A new bench-scale methodology for evaluating the flammability of live forest fuels

The present study proposes a new method in order to evaluate the flammability of live plant parts at bench-scale. Flammability parameters were estimated by the use of a mass loss calorimeter, and fuel moisture content was evaluated by the use of moisture analyser. Forest fuels ( Pinus pinaster, Cistus laurifolius, Lavandula stoechas and Daphne gnidium) were monitored under field conditions to detect the changes in the fuel moisture contents during the fire risk season. The combination of two different bench-scale devices (moisture analyser and mass loss calorimeter) guarantees fixed conditions for carrying out laboratory tests (constant bulk density and constant sample dry mass), thus resolving problems detected with other devices and methodologies.

Shear sensitivity of digested sludge: Comparison of methods and application in conditioning and dewatering

Shear sensitivity of digested sludge was evaluated by two methods: a CST shear test and a strain sweep rheological method of measuring yield stress. Sludge pretreatment by an enzyme formulation was used to alter the sludge's response to shear and, potentially, to improve dewaterability. Also varied were the polymer conditioning dose and the amount of shear applied by mixing. A bench-scale device was then used to simulate dewatering by belt press in order to assess the CST shear tests and the rheological test. CST-based shear tests showed that the optimum chemical conditioner doses with low shear levels became sub-optimal with increasing mixing times. For all three polymer conditioners, longer shear times increased the dose requirements. When the polymer dose was held constant, and the extent of mixing varied, the CST test was a poor indicator of effects on dewaterability. The benefits of enzyme treatment, apparent by actual dewatering, were not predicted by the CST results. In contrast, yield stress values were significantly correlated with cake solids values, and inversely correlated with filtrate solids. Yield stress is not adequate by itself to predict final cake solids after dewatering, because enzyme pretreatment gave higher solids concentrations when both shear extent and initial yield stress were held constant.

EFFECTS OF LATEX PAINT ON SMOKE HAZARD IN FIRES

A mass of heat and high concentration smoke are produced in building fires. Interactions of the paint on the walls and the high temperature smoke may occur in many types of fires scenarios. Experiments and chemical analysis have been conducted in a bench-scale device with the above assumption proved on the basis of the results. Painted boards with white latex paint displaced in the device make significantly high concentrations of some species of smoke and increase the smoke hazard. Language: en

An apparatus for screening fire suppression efficiency of dispersed liquid agents

The design, construction, demonstration, and operation of a bench-scale device capable of comparison screening the fire suppression efficiency of liquid agents are described in this paper. The apparatus is based on a well-characterized flame, a means to facilitate the introduction of liquid agents, and a way to generate liquid droplets. A porous cylinder in a counterflow diffusion configuration is used. A small-scale vertical wind tunnel, which allows for the delivery of a uniform flow of oxidizer to the burner and also assists in the delivery of liquid agent droplets to the flame, is used for the flow facility. Droplets are generated by a small glass nebulizer. The performance of the screening apparatus was evaluated using several liquid fire suppressants with different thermophysical properties. A test protocol is also proposed.

REVIEW OF U.S. ENVIRONMENTAL PROTECTION AGENCY RESEARCH IN OIL-WATER SEPARATION TECHNOLOGY

ABSTRACT The U.S. Environmental Protection Agency has sponsored two separate research contracts in the field of oil-water separation for the fiscal year 1974. One project, with Pollution Abatement Research, Inc., of Dallas, Texas, concerns the development of a chemically assisted, back-washable coalescer with chemically assisted backwash solids scrubber. This device is designed for use on offshore oil production platforms, although it has a wide potential of applicability. Preliminary tests made with large-volume samples of produced water from an offshore oil production platform yielded very promising results with less than 10 ppm produced oil in the effluent water. The second project, with the Ben Holt Company of Pasadena, California, is to develop a new concept of adsorption of oil-contaminated water onto a regenerable coked surface. The project is aimed at chemically stabilized emulsions and dissolved oils. A bench-scale device has been built, and testing has proven the feasibility of the concept. The rationale for the development of each of these devices is presented along with detailed information concerning test results of each device.