Liquid pulse injection

Masuda T, Mukai SR, Hashimoto K, The liquid pulse injection technique—a. new method to obtain long vapor-grown carbon-fibers at high growth-rates. Carbon, 31(5), 783-787, 1993. 

Asif et al. (1991) studied distributor effects in liquid-fluidized beds of low-density particles by measuring RTDs of the system by pulse injection of methylene blue. If PF leads into and follows the fluidized bed with a total time delay of 10 s, use the following data to calculate the mean-residence time and variance of a fluid element, and find N for the US model. 

The present study was conducted in an effort to better understand ACC mechanisms and to design practical ACC based on pulsed liquid-fuel injection suitable for propulsion devices. The controller utilized a simple fixed phase-delay approach that has been studied previously, but the direct liquid-fuel injection and the novel use of vortex-droplet interaction made the present study unique. The demonstration experiment in a 102-millimeter dump combustor showed that combustion instabilities can be successfully suppressed using properly designed pulsed liquid-fuel injection. 

Fignre 12-19 Pulse injection of gases or liquids into a chromatographic column with carrier gas or liquid for species A, B, and C. The chromatogram is recorded as the signal versus retention time in the column. 

In our lab, R.T.Ds are experimentally determined for the 3 phases by pulse injections of radioactive tracers in the real medium gaseous Ar or Kr liquid organometallic complexes, or halides solid neutron-irradiated metal catalysts. 

Hershkowitz et al. (3,10,11) measured adsorption and coke deposition on zeolite catalysts as well as catalytic cracking activity of FCC catalysts in short-contact-time interactions with decane at 573 K. They used 5 pi liquid decane injections to the catalyst bed to simulate FCC reaction conditions. Hershkowitz et al. focused on the measurement of adsorption and coke formation during the flow of the pulses. 

To measure affinity constants and other physico-chemical properties of binding such as the number of binding sites, two pulsed ultra-filtration measurements are carried out. First, an aliquot or pulse of a liquid is injected through the chamber, and the elution profile is recorded. Then, the chamber is loaded with a receptor, and the ligand is reinjected. If binding occurs, the elution profile will be delayed in proportion to the affinity constant. The con-... 

Fig, 10.24. Simplified schematics illustrating some deposition techniques (a) thermal evaporation (b) stamping (c) liquid-solid interface (d) electro-chemistry set-up (e) Langmuir-Blodgett technique (f) electro-spray deposition (g) pulse injection method (h) solution casting (i) spin-coating. 

Figure 3.14 (a) Cocurrent mobilization of two immiscible liquids, and established longitudinal contact interface in a microchannel (b) segmented-pulse injection of one liquid into the main flow of another immiscible liquid, and established transverse contact... 

In this section we present experimental evidence for a bifunctional alkane isomerization mechanism obtained by selective poisoning of the acidic sites of Pd-NiSMM with pyridine, which was pulse-injected into the liquid hydrocarbon feed stream. The possibility of additional poisoning of the metallic sites was checked by studying the hydrogenation of benzene and the isomerization and ring opening of methylcyclopentane (MCP). 

As can be seen from Figure 13-19, the residence-time distributions of the trickle-bed reactor, as determined by pulse injection, showed that considerable backmixing takes place in the reactor. As expected, tiiis decreases with increasing liquid feed. The external holdup was calculated from die residence-time curves. 

Glaser and Lichtenstein (G3) measured the liquid residence-time distribution for cocurrent downward flow of gas and liquid in columns of -in., 2-in., and 1-ft diameter packed with porous or nonporous -pg-in. or -in. cylindrical packings. The fluid media were an aqueous calcium chloride solution and air in one series of experiments and kerosene and hydrogen in another. Pulses of radioactive tracer (carbon-12, phosphorous-32, or rubi-dium-86) were injected outside the column, and the effluent concentration measured by Geiger counter. Axial dispersion was characterized by variability (defined as the standard deviation of residence time divided by the average residence time), and corrections for end effects were included in the analysis. The experiments indicate no effect of bed diameter upon variability. For a packed bed of porous particles, variability was found to consist of three components (1) Variability due to bulk flow through the bed... 

Siemes and Weiss (SI4) investigated axial mixing of the liquid phase in a two-phase bubble-column with no net liquid flow. Column diameter was 42 mm and the height of the liquid layer 1400 mm at zero gas flow. Water and air were the fluid media. The experiments were carried out by the injection of a pulse of electrolyte solution at one position in the bed and measurement of the concentration as a function of time at another position. The mixing phenomenon was treated mathematically as a diffusion process. Diffusion coefficients increased markedly with increasing gas velocity, from about 2 cm2/sec at a superficial gas velocity of 1 cm/sec to from 30 to 70 cm2/sec at a velocity of 7 cm/sec. The diffusion coefficient also varied with bubble size, and thus, because of coalescence, with distance from the gas distributor. 

In a recent study of the transport of coarse solids in a horizontal pipeline of 38 mrrt diameter, pressure drop, as a function not only of mixture velocity (determined by an electromagnetic flowmeter) but also of in-line concentration of solids and liquid velocity. The solids concentration was determined using a y-ray absorption technique, which depends on the difference in the attenuation of y-rays by solid and liquid. The liquid velocity was determined by a sail injection method,1"1 in which a pulse of salt solution was injected into the flowing mixture, and the time taken for the pulse to travel between two electrode pairs a fixed distance apart was measured, It was then possible, using equation 5.17, to calculate the relative velocity of the liquid to the solids. This relative velocity was found to increase with particle size and to be of the same order as the terminal falling velocity of the particles in the liquid. 

The general operation of the pilot scale reactor has be previously described by Pareek et. al. [3]. However, modifications were required to allow the injection of the gas and liquid tracers, and their subsequent detection at the outlets. The liquid tracer, 5mL Methyl blue solution (lOgL" ), was injected via a syringe inserted into the liquid feed line. Outlet samples were measured with a Shimadzu 1601 UV-Vis Spectrophotometer at a wavelength of 635nm. A pulse (20mL) of helium gas tracer was introduced using an automated control system, with the outlet concentration monitored in real-time with a thermal conductivity detector. Runs were carried out based on a two-level... 

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