Flash Evaporator System Research Articles

A theoretical and experimental study of a small-scale barometric sealed flash evaporative desalination system using low grade thermal energy

A barometric sealed flash evaporative desalination system was designed to ensure effective utilization of waste heat energy from a process plant. Unlike other conventional system, steam is not used in this desalination process. The plant was constructed in an existing thermal power plant, and experiments were carried out at various temperature differences between condenser reject and surface seawater at various flow rates. The operational and constructional parameters of the plant components were discussed and theoretical calculations for estimating the fresh water yield are presented. The influence of plant operating variables on fresh water generation using low grade thermal energy is experimentally studied. It is found that increase in the power plant condenser reject seawater temperature, feeding to the evaporator, influences the fresh water yield. Increased seawater flow rate to both the flash evaporator and the distillate condenser, decreased distillation plant saturation pressure lead to an increase in the fresh water generation. A maximum yield of 0.086 m3/h is obtained at 14.8 m3/h and 25 m3/h seawater flow rates to the evaporator and condenser respectively, for a flash evaporator system pressure of 49 mbar. The overall agreement between the measured and the theoretical calculations is of the order of 91–96%.

Spray cooling heat transfer: Technology overview and assessment of future challenges for micro-gravity application

Advanced on-board flight systems for future NASA space exploration programs consist of components such as laser-diode arrays (LDA’s) and multi-chip modules (MCM’s). Thermal management of these systems require high heat flux cooling capability (⩾100 W/cm 2), tight temperature control (approx. ±2 °C), reliable start-up (on demand) and long term stability. Traditional multiphase thermal control technologies for space flight (e.g., loop heat pipes, capillary pumped loops, etc.) satisfy the temperature control, start-up and stability requirements, but their heat flux removal capabilities are limited. Spray cooling can provide high heat fluxes in excess of 100 W/cm 2 using fluorinerts and over 1000 W/cm 2 with water while allowing tight temperature control at low coolant fluid flow rates. Spray cooling has been flight proven in an open loop configuration through the Space shuttle’s flash evaporator system (FES). However, several closed system issues require investigation to further advance the technology to a technology readiness level (TRL) appropriate for closed system space flight application. This paper provides a discussion of the current status of spray cooling technology as well as NASA’s goals, current direction, and challenges associated with the implementation and practice of this technology in the micro-gravity environment.

Beam arc distributions of shuttle pickup ions and their instabilities

Data from the Shuttle Potential and Return Electron Experiment (SPREE) flown as part of the Tethered Satellite System (TSS 1) are used to determine the detailed characteristics of beam arc distributions of pickup ions due to molecules outgassed or ejected from the shuttle. These ion distributions are only detected near the plane perpendicular to the magnetic field direction in an angular range of ±45° about the minimum angle to ram. Their flux is largest when the angle between this plane and the shuttle ram direction is smallest. Generally, ion spectra peak in the range 19 to 25 eV at the minimum angle between the perpendicular plane and the ram direction. The peak energy decreases smoothly as this angle increases. Weak fluxes are measured above the peak, to energies as high as 150 eV. Within the SPREE energy range, two‐dimensional distribution functions of beam arc ions in the perpendicular plane have teardrop shapes, symmetric about the minimum angle to shuttle ram with deep minima in the centers. Variations in the peak energies of differential number fluxes agree with collisionless trajectory analysis, assuming that the ions are H2O+ and allowing for different initial velocities before charge exchange. The lowest densities for beam arc ions occur during periods of purely residual outgassing from the shuttle. Ion densities increase by a factor of 5 during waste water dumps. The highest densities occur during operation of the flash evaporator system when the pickup ion densities in daylight can exceed 105 ions cm−3, about 30% of the estimated ambient plasma density. We also present a nonlinear numerical analysis to study the stability of beam arc generated plasma waves and explain electrostatic spectra measured during previous shuttle flights.

Space Shuttle Orbiter molecular environment induced by the supplemental flash evaporator system

The water vapor environment of the Space Shuttle Orbiter induced by the supplemental flash evaporator during the on-orbit flight phase has been analyzed based on Space II model predictions and orbital flight measurements. Model data of local density, column density, and return flux are presented. Results of return flux measurements with a mass spectrometer during STS-2 and of direct flux measurements during STS-4 are discussed and compared with model predictions.

Effects of chemical releases by the STS 3 Orbiter on the ionosphere

The Plasma Diagnostics Package, which was flown aboard STS 3 as part of the Office of Space Science first shuttle payload (OSS 1), recorded the effects of various chemical releases from the orbiter. Changes in the plasma environment were observed to occur during flash evaporator system releases, water dumps, and maneuvering thruster operations. During flash evaporator operations, broadband orbiter‐generated electrostatic noise was enhanced, and plasma density irregularities (ΔN/N) were observed to increase by 3–30 times with a spectrum which rose steeply and peaked below 6 Hz. Ions with energies up to several hundred eV were also observed during one flash evaporator operation. In the case of water dumps, background electrostatic noise was enhanced at frequencies below about 3 kHz and suppressed at frequencies above 3 kHz during the dump, and ΔN/N was also seen to increase by 5–6 times. Various changes in the plasma environment were effected by primary and vernier thruster operations, including increases in electron density by as much as 3 orders of magnitude, neutral pressure increases to as high as 10−4 torr from the nominal 10−7 torr, and perturbations in the spacecraft potential by several volts, particularly when measured in relation to the plasma potential in the wake. Thruster activity also stimulated electrostatic noise with a spectrum which peaked at approximately 0.5 kHz. In addition, ions with energies up to 1 keV were seen during some thruster events.

150-MGD Dual-purpose plant for the metropolitan water district of Southern California

Bechtel Corporation studied the feasibility of a dual-purpose power and desalination plant capable of producing up to 150-mgd of fresh water and a large block of power for Southern California. The three major electric utilities in Southern California proposed that the power features be expanded to two NSSS, each capable of providing steam for generating approximately 750 MW of electricity in addition to the capacity to operate a 350-MW turbine generator which would exhaust into the heater of the flash evaporator system. Conclusions reached were that the lowest cost water, 22 cents per 1,000 U.S. gallons, would result if the facility were erected on a man made island about one kilometer from the shoreline. Studies made later indicated that a single-level desalting plant would probably be most appropriate and that electric motor drives for the large pumps would result in the lowest first cost and lowest operating cost. Hydraulic model studies and laboratory tests proved the island defense design to be stable against the maximum storm wave.

CB&I Develops Evaporator for Pulp Industry

RETURN TO ISSUEPREVNewsNEXTCB&I Develops Evaporator for Pulp IndustryDigest flash evaporator system will be installed at Canadian pulp plant, offers 10% cut in capital and operating costsCite this: Chem. Eng. News 1966, 44, 12, 46–47Publication Date (Print):March 21, 1966Publication History Published online6 November 2010Published inissue 21 March 1966https://doi.org/10.1021/cen-v044n012.p046Copyright © 1966 AMERICAN CHEMICAL SOCIETYArticle Views7Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (249 KB) SUBJECTS:Pulp Get e-Alerts