Experimental studies of air-blast atomization on the CO_(2)capture with aqueous alkali solutions

In this work,an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA(mono-ethanol-amine)and Na OH solutions.The effects of gas flow rate,the liquid to gas ratio(L/G),the CO2 concentration on the CO2 removal efficiency(η)and the volumetric overall mass transfer coefficient(KGav)were investigated.The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance.For the aqueous MEA and Na OH solutions,the experimental results show that theηdecreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G.The effects on KGavare more complicated than those forη.When the CO2 concentration is low(3 vol%),KGavincreases with increasing gas flow rate while decreases with increasing L/G.However,when the CO2 concentration is high(9.5 vol%),as the gas flow rate and L/G increases,KGavincreases first and then decreases.The aqueous MEA solution achieves higherηand KGavthan the aqueous Na OH solution.The air-blast atomizing column shows a good performance on CO2 capture.

Carbon Dioxide Sequestration via Steelmaking Slag Carbonation in Alkali Solutions: Experimental Investigation and Process Evaluation

Carbon dioxide mineral sequestration with steelmaking slag is a promising method for reducing carbon dioxide in a large- scale setting. Existing calcium oxide or calcium hydroxide in steelmaking slag can be easily leached by water, and the formed calcium carbonate can be easily wrapped on the surface of unreacted steelmaking slag particles. Thus, further increase in the carbonation reaction rate can be prevented. Enhanced carbon dioxide mineral sequestration with steel- making slag in dilute alkali solution was analysed in this study through experiments and process evaluation. Operating conditions, namely alkali concentration, reaction temperature and time, and liquid-to-solid ratio, were initially investigated. Then, the material and energy balance of the entire process was calculated, and the net carbon dioxide sequestration efficiency at different reaction times was evaluated. Results showed that dilute alkali solution participated in slowing down the leaching of active calcium in the steelmaking slag and in significantly improving carbonation conversion rate. The highest carbonation conversion rate of approximately 50% can be obtained at the optimal conditions of 20 g/L alkali concentration, 2 mL/L liquid-to-solid ratio, and 70 ℃ reaction temperature. Carbonation reaction time significantly influences the net carbon dioxide sequestration efficiency. According to calculation, carbon dioxide emission of 52.6 kg/t- slag was avoided at a relatively long time of 120 min.

Calculation of Interaction Parameters from Immiscible Phase Diagram of Alkali Metal or Alkali Earth Metal-Halide System by Means of Subregular Solution Model

In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows:Gm^E=xAxB[(λ11+λ12T)+(λ21+λ22T)xB]The calculation of the model parameters, λ11, λ12, λ21and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the .calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.

Low-concentration sodium hydroxide solution injection in normal liver parenchyma of rabbits

BACKGROUND: Percutaneous ethanol injection has been widely used as a non-surgical therapy for liver cancer, but it has some shortcomings such as local diffusion and une- qual permeation. This study was designed to observe the volume, controllability and completeness of necrosis after injection of low concentration sodium hydroxide in the normal liver parenchyma so as to assess its possibility in treatment of liver cancer instead of ethanol. METHODS: Twenty-seven New Zealand rabbits were di- vided randomly into 9 groups (Aa, Ab, Ac, Ba, Bb, Bc, Ca, Cb, and Cc) by a 3 × 3 (three-by-three) factorial de- sign, each consisting of 3 rabbits. Group A was given sodi- um hydroxide solution at a concentration of 5%, while B at 2.5% and C at 1% in liver parenchyma. Each group re- ceived three doses of the solution: a (0.2 ml), b (0.5 ml) and c (1.0 ml). Then another 3 rabbits as side-effect group were dropped with sodium hydroxide solution in their liver lobe space. Liver and renal function changes in all the rab- bits were compared after injection with pre-injection. RESULTS: All the lesions were localized. At the concentra- tion of 2.5% and 5%, the lesion volume increased with the dose increased from 0.2 ml to 1.0 ml (P < 0. 05). No sig- nificant differences were found in the lesion volume of the groups receiving the same dose but different concentration. Changes in liver and renal function were not significant 7 days after injection, compared with those before injection. CONCLUSIONS: 2.5% and 5% sodium hydroxide solution could control local complete necrosis in normal liver. With regard to safety, 2.5% alkali solution is considered promis- ing as a new agent for intratumoral injection therapy in- stead of ethanol.

Engineering the Thermoelectrical Properties of PEDOT:PSS by Alkali Metal Ion Effect

Engineering the electrical properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)holds great potential for various applications such as sensors,thermoelectric(TE)generators,and hole transport layers in solar cells.Various strategies have been applied to achieve optimal electrical properties,including base solution post-treatments.However,the working mechanism and the exact details of the structural transformations induced by base post-treatments are still unclear.In this work,we present a comparative study on the post-treatment effects of using three common and green alkali base solutions:namely LiOH,NaOH,and KOH.The structural modifications induced in the film by the base post-treatments are studied by techniques including atomic force microscopy,grazing-incidence wide-angle X-ray scattering,ultraviolet–visible–near-infrared spectroscopy,and attenuated total reflectance Fourier-transform infrared spectroscopy.Base-induced structural modifications are responsible for an improvement in the TE power factor of the films,which depends on the basic solution used.The results are explained on the basis of the different affinity between the alkali cations and the PSS chains,which determines PEDOT dedoping.The results presented here shed light on the structural reorganization occurring in PEDOT:PSS when exposed to high-pH solutions and may serve as inspiration to create future pH-/ion-responsive devices for various applications.

Leaching improvement of ceramic cores for hollow turbine blades based on additive manufacturing

The precision casting method based on aluminabased ceramic cores is one of the main techniques used to manufacture hollow turbine blades.Additive manufacturing(AM)technology provides an alternate solution to fabricating ceramic cores quickly and precisely.As the complexity of the structure increases and the strength of the material improves,the leaching process of the cores becomes more complicated.This study proposes a compound pore-forming method to increase the porosity of ceramic cores by adding a preformed-pore agent and materials that convert to easy-to-corrode phases.The preformed-pore agents(e.g.,carbon fibers)can be burned off during sintering to form pores before the leaching,and the easy-to-corrode phases(e.g.,CaCO3,SiO2,^-A12O3)can be leached firstly to form pores during the leaching process.The pores formed in the aforementioned two stages increase the contact area of the cores and leaching solution,thus improving the leaching rate.In the current study,the additive amount of the preformed-pore agent was optimized,and the effect of the easy-to-corrode phases on the comprehensive properties of the cores was then compared.Based on this,the corresponding model was established.