Showing papers on "Fouling published in 1976"

Prefiltration of cottage cheese whey to reduce fouling of ultrafiltration membranes

Abstract: To improve membrane performance and extend the interval between cleanings, a two-step ultrafiltration process is proposed consisting of prefiltration with an open-pored membrane followed by normal ultrafiltration. Three to fourfold increases in permeation rate were observed in laboratory-scale experiments when whey was prefiltered through ultrafiltration membranes of graded porosity to remove microorganisms and protein complexes. It is postulated that fouling occurs when the larger whey constituents settle on the membrane in a lattice network which fills in and is coated over with smaller, sheet-forming whey proteins such as β-lactoglobulin. Fouling substances were studied with scanning electron microscopy and identified by sodium dodecyl sulfate gel electrophoresis.

Inter-relation of corrosion and fouling for metals in sea water

Abstract: Carbon steel, aluminum, and copper alloys submerged at the Inco Wrightsville Beach, NC, test station were evaluated by International Nickel Co., Inc., for their ability to resist sea marine fouling for up to 5 years. The study demonstrated that the fouling properties are influenced by the corrosion characteristics of the alloys, which can be placed into one of three classes: highly corrodible metals, passive metals, and toxic film-forming metals. Highly corrodible alloys such as steel will foul; the fouling can be removed easily with the loose corrosion product, sloughing off at intervals during exposure. However, the fouling on passive alloys is tightly adherent and restricts the diffusion of oxygen to the metal surface. The only effect on corrosion occurs when the material is sensitive to oxygen-concentration cells, causing crevice corrosion beneath the fouling organisms. The copper-base alloys possess fouling resistance because of the formation of an adherent cuprous oxide corrosion product that is toxic to the organisms. Materials such as beryllium and lead, which are expected to form toxic films, do not remain free of fouling.

Low leaching antifouling organometallic polyesters

Abstract: Marine structures which are designed to be submerged in an aqueous environt containing fouling organism are protected fro fouling by the use of an organotin containing polymer wherein the tin is chemically bonded to the polymer. The polymer inhibits fouling of the exposed surface of the structure while minimizing the adverse effects on the surrounding environment due to reduced leaching of the organotin compound from the polymer.

Prevention of fouling of marine structures such as boat hulls

Abstract: A method of coating marine structures including marine vessel hulls is disclosed, the method comprising painting the surfaces of the structure to be exposed to fouling conditions in salt water including sea water and brackish water, with a paint containing certain 3-isothiazolones in an amount to control marine plant and animal life such as algae, hydroids, and barnacles.

Prevention of fouling in polymerization reactors and antistatic agents

Abstract: An olefin is polymerized in a hydrocarbon diluent in a turbulent reaction zone to produce particles of polymer which are substantially insoluble in the diluent. Fouling of the reactor by adherence of polymer particles to the walls of the reactor is reduced by adding to the reaction medium a composition which comprises a porphyrin compound, alone or together with a metal alkyl sulfosuccinate. This composition is also useful as an antistatic agent for liquid hydrocarbons and halohydrocarbons.

Method for improved distillation of ammonia from weak ammonia liquor

Abstract: Fouling of an ammonia still, used for removal of ammonia from weak ammonia liquor derived from a coal coking operation, is alleviated by pre-precipitating insoluble calcium salts from the ammonia liquor by treatment of the liquor with lime prior to introduction into a single-leg still.

Method of preventing the accumulation of micro-organisms in thermal energy conversion systems

Abstract: In an ocean thermal energy conversion system utilizing solar energy stored as heat in tropical waters to generate electricity, the evaporating and condensing functions of the heat exchangers are interchanged in order to prevent the accumulation of micro-organisms on their surfaces. The surfaces of the heat exchangers are also mechanically brushed or scraped so as to remove any thin films of microbial slime. In order to remove additional micro-organisms from the surfaces of the heat exchangers, the flow of hot and cold sea water through each of the heat exchangers is interchanged preferably on a daily basis. Thus, micro-organisms from the warm surface waters that attach themselves to one heat exchanger surface will be destroyed by the cold water that flows through that heat exchanger on the next day. On the other hand, the organisms that live in the cold water at great depths cannot survive the next day's warm water environment which is caused by alternating the flow to the two heat exchangers.

UV steriliser for water - maintains efficiency of UV lamp by keeping this out of direct contact with water

Abstract: In the operation of an appts. esp. designed for UV-sterilisation of water, with a dip vessel and lamp immersed therein, the water to be treated lies against the inner wall of the vessel but has no contact with the lamp. Specifically the dip vessel is provided with a central bottom outlet and a sealed cover with a central holder for the submerged UV-lamp. By preventing direct contact of the water and the quartz sheath of the UV-lamp, reduction of UV-emission due to fouling of the quartz surface is eliminated.

Ocean thermal power plant heat exchangers

Abstract: The cost-performance characteristics of heat exchangers for the ocean thermal power cycle are studied. Linde prefers shell-and-tube exchangers with the seawater tube side to minimize corrosion and fouling. The use of heat transfer enhancements is considered in order to decrease the exchanger cost. Corrosion and biofouling by seawater are studied in connection with choice of materials of construction. Preferred methods of control are chlorination and continuous mechanical cleaning. The hydraulic problems involved in the evaporator design are studied. The use of sprayed bundles, and of multiple flooded bundles, is considered. A system optimization program is written and used to obtain heat exchanger designs optimum from the system viewpoint. Exchangers using enhanced tubes cost 942 $/KW for a 100-MW plant, or 33% less than with plain tubes. The cost penalty for substituting multiple flooded bundles for sprayed evaporatory bundles is 325 $/KW.

Marine fouling of titanium heat exchangers

Abstract: : A series of marine fouling experiments was conducted at Freeport, Texas, on two single-pass titanium heat exchangers. The exchangers, which were constructed with commercially pure titanium tubes (5/8-inch (1.59-centimeter)) outside diameter by 30-inch (76.3-centimeter length) and 6Al-4V alloy tube sheets and headers, were operated on natural seawater. One of the exchangers was fed electrolytically chlorinated seawater, while the other was run with untreated seawater feed. Velocity and chlorination levels were varied to determine the effect of these two variables on fouling of the titanium surfaces. Operating conditions similar to those that might be expected in shipboard heat exchanger/condenser usage were modeled.

Multistage cooling of crude hydrocarbon gases

Abstract: Crude gas, such as cracking gas, is subjected after quenching to a two stage cooling system wherein water is employed in the first stage as both a direct contact coolant and scrubbing agent to remove condensed out hydrocarbons and solids from the gas The scrubbing liquid in the first stage is subjected to a rough decanting step to separate hydrocarbons from water which is to be recycled; however, no indirect heat exchangers are used for recycle water, thereby avoiding clogging The gas recovered from the first cooling stage is at about the water dew point of the gas, and is then cooled in a second stage in direct contact with refrigerated water, but because the fouling substances of the gas are removed in the first stage, there is no clogging problem when the recycle water is cooled in an indirect heat exchanger with an external refrigerant

Anti-fouling agent for materials used in water

Abstract: PURPOSE: An anti-fouling agent comprising a mixed liquid of latices and specific substances for fishing nets with excellent and long-lasting effect, from which effective components are constantly eluted. COPYRIGHT: (C)1977,JPO&Japio

Ash fouling potentials of Western subbituminous coal as determined in a pilot plant test furnace

Abstract: The fouling potential of subbituminous coals is proportional to sodium content, tending to plateau at higher sodium levels. It increases exponentially with coal ash content at all sodium levels. At similar sodium and ash levels, subbituminous coal fouling potentials are at least as great as of lignite. On the basis of samples tested and other ash survey work on Western coals, there is no evidence of the simultaneous occurrence of high sodium and high ash, a coincidental condition that would lead to high fouling in subbituminous coals. Because of this, subbituminous coals in general can be expected to show less ash fouling problems than lignite coals. In general, experience burning Western coals in Eastern boilers would indicate that samples having high sodium would give very severe fouling conditions by Eastern standards, whereas samples with low sodium would give fouling experiences comparable to the normal experience with Eastern coals.

Geothermal energy needed: effective heat transfer equipment

Abstract: For large-scale application of geothermal energy from steam and hot water, effective heat exchange equipment is needed to overcome the fouling and corrosion from such pollutants as silica, lime, CO/sub 2/, and sulfurous compounds that impede efficient heat transfer. The problems are discussed in regard to both binary cycle units and refrigeration systems. (LBS)

Foul water treating method and apparatus

Abstract: PURPOSE:To attain perfect cleaning of foul water by automatically adjusting the treating steps according to the degree of fouling of water, and toprevent release of foul water by detecting the degree of water fouling.

Fouling Mechanism in Liquid Phase Oxidation of Carbon Monoxide Catalyzed by Palladium(II) Salts in Acetic Acid Solvents

Abstract: The fouling mechanism during catalytic activity in the liquid phase oxidation of carbon monoxide has been investigated using catalytic acetic acid solutions containing palladium(II) salts and lithium nitrate as oxidants. The fouling phenomenon becomes understandable upon the recognition that the active palladium catalysts react with the nitrite ion formed during the oxidation reaction to produce inactive-stable complexes.