Showing papers on "Spray tower published in 1999"

Analysis of Mass Transfer Performance in an Air Stripping Tower

Abstract: The carryover of working solution in a traditional stripping tower is of serious concern in real applications. A U-shaped spray tower to prevent carryover has been designed to study the stripping of water vapor from aqueous desiccant solutions of 91.8 to 95.8 wt% triethylene glycol. In this study, water vapor was removed from the diluted desiccant solution by heating the solution and stripping it with the ambient air. Therefore, the solution was concentrated to a desired concentration. This spray tower was capable of handling air flow rates from 3.2 to 5.13 kg/min and liquid flow rates from 1.6 to 2.76 kg/min. Since the literature data on air stripping towers are limited, studies on the mass transfer coefficient and other mass transfer parameters were carried out in this study. Under the operating conditions, the overall mass transfer coefficient calculated from the experimental data varied from 0.053 to 0.169 mol/m3·s. These corresponded to heights of a transfer unit of 2.3 to 0.71 m, respectively. The r...

Mass Transfer in Absorption of Lean Gas Using Small Spray Column

Abstract: Mass transfer in the absorption of lean NH3 with water spray is examined under various experimental condition, using a small spray column. The absorption rates of NH3 are affected by both gas- and liquid-phase mass transfer resistances in the vicinity of the nozzle exit. The observed gas phase diffusion fluxes of NH3 show good agreement with the empirical correlation by Ranz-Marshall.Taking the effect of gas- and liquid phase mass transfer resistances on the absorption rates into consideration, a new simulation technique is proposed for the absorption of lean gas using a small spray column. The present model can accurately predict the amount of absorbed NH3 by water spray.

Setting of ammonia injection quantity in waste gas treatment apparatus of refuse incinerator

Abstract: PROBLEM TO BE SOLVED: To provide a method for setting ammonia injection quantity in order to carry out treatments of desulfurization, denitrification and dioxins removal at a same stage in a waste gas treatment apparatus in a refuse incinerator. SOLUTION: In a waste gas treatment apparatus of a refuse incinerator wherein hydrochloric acid concentration of a waste gas is lowered to a specified level in a lime spray tower and sprayed lime is captured together with ash by an electric precipitator, and then waste gas temperature is controlled within a specified range by a heat exchanger before being guided into an adsorption tower packed with granular active carbon, and the waste gas is brought into contact with the active carbon before being discharged to a flue, SO2 and dioxins are adsorbed by the granular active carbon, NOx is decomposed under the presence of NH3 injected from the heat exchanger into the flue, and parts of them are filtered and removed as NH4 Cl together with dust by an active carbon layer of the adsorption tower. The granular active carbon which has adsorbed SO2 , dioxins and HCl is guided to a desorption tower and heated so as to desorb SO2 , decompose the dioxins and desorb HCl. Quantity of NH3 injection is set on the basis of NOx concentration at an inlet of the adsorption tower and NOx removal rate or NOx concentration at the inlet of the adsorption tower and NOx concentration at an outlet thereof.

Kinetics and reactor simulation for polyethoxylation and polypropoxylation reactions

Abstract: The kinetics of, respectively, polyethoxylation and polypropoxylation reactions in the presence of a hydrophobic starter and a basic catalyst are presented with a general approach based on the reaction mechanism. A general kinetic model and a simplified model useful to simulate the alkylene oxide consumption and the oligomers distribution in well-mixed semibatch reactors are presented. Kinetic laws and related parameters have been tested by simulating a spray tower pilot plant reactor with two alternative models considering the liquid in the drops emerging from the spray nozzle to be either stagnant or well mixed. The later possibility seems to be the correct one.

Operation of waste gas treatment apparatus in waste incinerator

Abstract: PROBLEM TO BE SOLVED: To provide an operation method of a waste gas treatment apparatus for removing dioxins by realizing an optimum operation temperature so as to demonstrate stable performance. SOLUTION: Hydrochloric acid concentration of a waste gas is lowered to a specified level in a lime spray tower and sprayed lime together with ash is collected by a dust collector. Then, waste gas temperature is controlled to a temperature of 120-160 deg.C by a heat exchanger and is guided into an adsorption tower filled with granular active carbon in order that SO2 and dioxins are adsorbed by the granular active carbon. NOx is decomposed by NH3 introduced into a flue of the heat exchanger and a part of it together with dust is filtered and removed as NH4 Cl by the active carbon in the adsorption tower. Then, the active carbon which has adsorbed SO2 , dioxins and HCl is guided into a desorption tower, and the SO2 is desorbed, the dioxins are decomposed and the HCl is desorbed and the active carbon which has undergone desorption and regeneration is separated into granular active carbon, dust and active carbon powder by a sieving device. The granular active carbon is returned to the adsorption tower, desorbed gas is returned to the lime spray tower so as to be desalted and the SO2 is fixed by the lime, and the dust and active carbon powder are returned to a furnace or the lime spray tower.

The Influence of Aerodynamic Characteristics on Mass Exchange Efficiency in FGD Scrubbers

Abstract: On the basis of the model for aerodynamic characteristics of a FGD spray tower, a model for mass exchange in a single spray bank scrubber was developed. The relation for mass transfer units with respect to parameters characterizing dispersed and continuous phases was determined. Predictions of the scrubber efficiency for very fast and very slow reaction rates in the slurry are presented and discussed. The influence of sulfur dioxide concentration in gas and slurry feeds on the absorption efficiency are shown. A qualitative comparison with experimental data presented in the literature was performed.

Process and system for exhaust gas treatment

Abstract: of EP0967003Processes and systems for exhaust gas treatment are described in which a much less amount of an alkaline agent is used for neutralization, the amount of discharged salt can be reduced, and high-purity acids can be recovered for recycling. An exhaust gas is deacidified in a first spray tower to remove acid gas components. A cleaning solvent after absorbing HCl gas is withdrawn from the first spray tower and then introduced into a stock solution chamber of an electrodialyzing vessel. Meanwhile, a thin HCl solution is introduced into a permeation chamber of the elctrodialyzing vessel from an HCl tank. The electrodialyzing vessel comprises section chambers which are formed by cation exchange membranes and anion exchange membranes alternately disposed. The cleaning solvent after the absorption of HCl gas goes into every second one of the section chambers, so that a thin HCl solution is concentrated and recovered.

Fire engine with high-pressure spray tower ladder

Abstract: PROBLEM TO BE SOLVED: To discharge water to the inside of a building and to extinguish through the use of a small amount of water by mounting a high pressure pump and aiming extremely fine water particles in the state of spray by a jet nozzle provided at the tip of a water discharging tower of a deflecting type. SOLUTION: The high pressure pump is mounted to a fire-engine to drive by the engine of the vehicle. Water pipes are fixed to deflection towers 1 and 2 to send high-pressure water to the tip of a tower and a high-pressure spray nozzle 4 is fixed to the tip of the tower to discharge water. A tower tip part 3 is made extensible to enter inside of a building and mounts a water tank for extinguishing. In order to prevent the loss of water, the nozzle 4 is mounted at the tip of the tower like this to extinguish by spraying extremely fine water particles. The smaller water particles are, the larger an extinguishing effect is and the larger extinguishing effect is realized through the use of a small amount of water. In the case of high-pressure spraying, a water discharging amount to use for extinguishing is very small. Then the water pipe of the tower can be thin and reaction force can be small to allow the tower to sufficiently play a function by a small size and small weight.