The effect of electric fields upon liquid extraction. Progress report

Technical Report · Wed Apr 13 04:00:00 EDT 1988

DOI:https://doi.org/10.2172/10182284· OSTI ID:10182284

Carleson, T E

A series of mass transfer studies were conducted for the extraction of solute from droplets falling in an electric field. The experiments were planned such that the dispersed phase resistance was controlling. In one series of experiments single drops were formed from a charged nozzle and allowed to fall through a continuous, dielectric phase. The drop size and velocity were correlated by means of a simple force balance. Drop mass transfer coefficients were calculated for the drop free fall period and were compared to predictions based upon literature correlations for an oscillating droplet in-the absence of an electric field. Droplet size and velocity were approximately predicted by a staple force balance whereas the mass transfer coefficient was approximately 25--250% higher than that predicted. Droplet extraction efficiencies Increased about 20--30% in the presence of electric fields up to 2 kv/cm. For the same field, the drop diameter decreased 30--50% and the terminal velocity increased by up to 50%. The enhancements for the toluene-water system can be ascribed to increases in terminal velocity and decreases in drop diameter. The mass transfer model for freely falling drops proposed by Skelland and Wellek roughly predicts the moderate mass transfer efficiency increases (about 18% at 1 kv/cm) for the toluene water system but failed to predict the increases (about 25% at 0.5 kv/cm) for the heptane furfural system. The second series of experiments involved the formation of a swarm of droplets In a three stage sieve tray column. In a separate series of experiments. the effect of the electric field upon mass transfer from drops exhibiting interfacial turbulence was evaluated.

• Research Organization: Idaho Univ., Moscow, ID (United States). Dept. of Chemical Engineering
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG07-86ER13572
• OSTI ID: 10182284
• Report Number(s): DOE/ER/13572--1; ON: DE92040894
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105
42 ENGINEERING
420200
DIELECTRIC MATERIALS
DROPLETS
ELECTRIC FIELDS
EXTRACTION
FACILITIES, EQUIPMENT, AND TECHNIQUES
FURFURAL
HEPTANE
INTERFACES
LIQUIDS
MASS TRANSFER
PROGRESS REPORT
SEPARATION PROCEDURES
SIZE
TOLUENE
TURBULENCE
VELOCITY