Applying EMF

Electromagnetic filters (EMF)

USING THE TECHNOLOGY OF MAGNETIC PRECIPITATION IN VARIOUS INDUSTRIES.

Magnetic precipitation technology with application of electromagnetic filters (EMF) is intended for fine and high-speed removal of magneto-susceptible impurities of iron, nickel, cobalt or compounds of liquids and gases on their basis.

Availability of magneto-susceptible impurities, i.e. corrosion products, in various liquid and gaseous fluids is inevitable consequence of various technological processes. In most cases, even a small presence of impurities in the final product deteriorates its quality and causes adverse effects, limiting a scope of its utilization. This, in turn, leads to inevitable economic losses.
Modern cleaning plants do not ensure effective removal of magneto-susceptible impurities due to:

high dispersity of impurities;
very low or, conversely, very high concentrations of impurities;
necessity to clean up large volumes of the carrier medium;
presence of highly aggressive environment;
high temperature environment;
impossibility of using other cleaning devices.

These and certain other conditions are present in many technological processes of various industries. From a wide spectrum of possible applications of the EMF, here are considered only the most characteristic:

in thermal and nuclear power plants;
in metallurgical enterprises;
in the chemical industry;
in mechanical engineering and metalworking industry;
in the oil-and-gas industry;
in the extractive industries;
in the food, pharmaceutical, perfumery and cosmetic industries.

The use of EMF in thermal and nuclear power engineering allows 2-3 times to reduce the content of iron oxide impurities in the condensate and feed water and, accordingly, reduce the amount of their deposits on steam generating surfaces. This improves heat transfer and contributes to fuel economy as a whole, significantly slowing down the intensity of corrosion processes, prevents overheating of the heating surfaces, deformation and ruptures of the pipes and, as a result, increases their operational life. Moreover, highly-efficient cleaning of the technological condensate allows returning it in the working technological cycle of TPP or CHP, while avoiding considerable losses of chemically treated water and energy.

The metallurgical plants are among industrial facilities where it is extremely necessary to clean large volumes of liquid media from ferriferous impurities. Recirculating water used for hydraulic descaling and enriched by dispersed oxide scale of various fractions, which cools a roll table of the rolling mill and a rolled plate. The coarsest fraction is deposited in open water ponds, worsening ecology of the environment. Relatively fine fraction circulates in recirculating system with content up to 50...100 mg/l, causing increased wear of equipment and periodic obstruction of the nozzles. It breaks the mode of cooling of the rolls (especially of hollow types), leading to more frequent their replacement and, consequently, additional downtime of the rolling mill. In addition, particles of the oxide scale, which penetrates on the rolls with cooling water, are «rolled» into the surface of rolled sheet, worsening its quality and creating the centers of the formations of the subsequent corrosion.

The use of EMF in metallurgy allows 5-10 times to reduce a content of oxide scale in the circulating and waste waters of the rolling mill, to improve the quality of hot-rolled products, reduce the number of equipment’s failures and to improve the environmental situation around the enterprise.

In the chemical industry the presence of ferriferous impurities in the liquid and gaseous ammonia, low-concentrated nitric acid, and ammonia water of analytical grade causes a number of negative consequences.

So, for example, with a relatively low concentration of iron in ammonia (0.1...1.0 mg/kg) formed on the platiniferous catalysts of the contact apparatus, the sediments containing up to 20...50% of iron and its oxides, poison the catalyst, close its active centers and penetrate into the catalyst itself. Poisoning of the catalyst leads to lower degree of conversion of ammonia, being an important operational characteristic of the whole production of ammonium acid, in a considerable amount (6...8%), causing a reduction in the production of finished products, increases the consumption of ammonia, catalyst and energy.

The use of EMF in chemical technology allows providing the standardized indicators of products, to reduce its off-grade amount, in particular, is 2-3 times to lower the content of ferruginous impurities, thereby increasing the service life of main equipment, including a decrease in the intensity of poisoning of the catalysts and increase in degree of chemical synthesis by 20÷40 %.

In mechanical engineering and the metalworking industry, one of the problems is the presence of iron particles in the lubricating-cooling liquids (emulsions) of machinery of metalworking industries, which are products of metal processing and can lead to premature wear of the cutting and machining tools. Highly dispersed metal particles, getting into the zone of cutting tool, reduce its service life, clog cooling nozzles and channels of the machines, which lead to additional downtime of machines or failure of their parts or units.

The presence of ferruginous particles, i.e. wear debris of the friction surfaces, pinion pairs and other contacting pairs, in greasing and fuel of ship and railway internal-combustion engines, reduces their lifetime, leads to necessity of a frequent changing the oils.

One of upcoming trends of application of the EMF is cleaning of production areas, for example, welding productions, and casting shops from ecologically harmful iron-oxide aerosol.

Use of the EMF in mechanical engineering and metal-working industry allows increasing by 28-36% a working resource of metal-cutting and the machining tool, to lower a wear of details and units of internal-combustion engines, to reduce a number of machinery equipment failures, to raise ecological purity of premises.

In the oil and gas industry a major problem is the admixing of ferriferous impurities to the oil and natural gas, which are pumped through pipelines over long distances.

So the gas transported via thousand-kilometer pipelines is so enriched by fine-grained admixtures – corrosion products that consumers face a need for additional cleaning.

In oil and oil products (high-octane- and diesel fuel), as a result of their transportation, there is a considerable quantity of disperse products of corrosion. It worsens quality and grade of a product, reduces lifetime of units and assemblies of engines, causing a significant economic damage. Highly effective and high-speed removal of finely dispersed ferriferous impurities from large volumes of these liquid media is a challenging and largely unsolved task.

The application of electromagnetic filters in the oil and gas industry allows solving these problems, ensuring a high-speed cleaning from fine-grained products of corrosion with the minimum hydraulic losses.
In this industry, an important feature of the method of magnetic precipitation is the possibility of using filters, in which the source of magnetic fields are not electric coils but highly inductive permanent magnets, which allows the use of filters in explosive production facilities.

The area, in which a technology of sorting the materials according to their magnetic properties and separation of magnetic materials from non-magnetic ones is traditionally used, this is mining industry. So, for example, by means of magnetic filters-precipitators and the deposition apparatuses, on the ore mining and processing plants the separation and enrichment of iron, nickel, cobalt, titanium, manganese ores and other complex mixes are carried out. With the help of new designs of electromagnetic filters-precipitators of continuous action, the efficiency of this process can be significantly improved.

In the food industry, high requirements are placed to water quality, as being an important component of most food products. Presence of fine-dispersed iron particles in some products of long storage, for example, wines, juices, mousses, dairy and lactic products, and also in products for children, where use of preserving agents is restricted, shortens terms of their storage and alters the flavoring qualities.

Water-treatment installations with traditional cation- and anion-exchange, sulfonated carbon and other filters, which are used in such processes, allow maintaining a high water quality with regard to the majority of controlled parameters, except the fine-dispersed ferriferous impurities.
In this area, small in size EMFs could provide 99.99% extraction of ferromagnetic impurities.

The pharmaceutical, perfume and cosmetic industries require a high degree of purity of the liquids, for example, in liquid medicinal forms. The fine-dispersed ferriferous impurities present in solutions, often react with other organic and chemical components that leads to some changes of final product and sometimes – to decrease in its overall value. For this reason, strict requirements are introduced to quality of obtained solutions, which exclude a presence in the initial components and in final product of any impurities. At the same time, high dispersion of ferruginous particles that is present in the source water can greatly complicate process of product manufacturing. For example, obtaining of the clean water by double distillation – one of the main used methods – does not guarantee the removal of iron microparticles, because, due to the high dispersion, they are easily transported with the steam and get to the final product.

The EMFs are easily fit in any process due to its compactness, and even having the small dimensions ensure very high level of purification from magneto-susceptible impurities.

Technology of magnetic cleaning provides:

level of purification to a residual content of magneto-susceptible impurities 10-7...10-9 (in mass fractions);
removal of the particles with size less than 0.1 µm from the medium;
high-speed cleaning mode – 0.1...15 m/s in compact devices with performance range of 1.0 to 1000 t/h;
ability to clean at maximum permissible temperatures of media up to 500 °C;
high efficiency of operational indicators: electricity consumption up to 0.4 kW at cleaning performance of 1 t/h;
possibility of application in potentially explosive processes with using a system of permanent magnets.

TECHNICAL AND ECONOMIC EFFICIENCY OF APPLYING ELECTROMAGNETIC FILTERS IN ELECTRIC POWER INDUSTRY

Technical efficiency of the electromagnetic filter (EMF) operation is determined by the degree of purification of the coolant from ferromagnetic iron impurities. Highly effective operation of the EMF on coolant purification in TPPs/CHPs has a positive effect on the following main factors of their functioning:

cleaning of process condensate from ferriferous impurities allows to return it into a operational cycle of TPP/CHP, avoiding, thereby, significant losses of chemically treated water and energy;
reduced amount of iron oxide deposits on the blades in the control stage of the high pressure cylinder in a turbine allows to maintain the standard value of pressure, and therefore to avoid of underproduction of the electric power;
reduced amount of iron-oxide deposits on heat transfer surfaces of steam generators leads to an increase of heat transfer coefficient. This contributes to the reduction of fuel consumption, delays a growth of temperature difference and a growth of temperature of metal pipes, therefore, a likelihood of their breakage and a number of emergency shutdowns decreases;
as a result of decrease in number of emergency shutdowns, total number of start-up of power unit is diminished, and losses of chemically cleaned water become lower;
when starting the power unit, the use of EMF provides accelerated reduction of high concentration of ferriferous impurities in the feed water to the required level, thereby reducing the process of washing the water-steam circuit and accelerating the generator’s switching on to the network. In addition, significantly reduced are the number of ferriferous impurities which get in the steam generator and turbine during their circuit washing;
intensive de-ironing of condensate in the electromagnetic filter reduces loading of water-treating and chemical water treatment plant of the power unit, increasing their performance.

TECHNICAL AND OPERATIONAL CHARACTERISTICS OF EMF

The EMF designs developed provide an effective purification of the coolant with any concentrations of ferriferous impurities occurring on power facilities with a performance range from 10 to 2000 m3/h.

Technical characteristics of the EMF-4/100

Productivity, [m3/h]	100
Cleaning efficiency for ferromagnetic impurities, [%]	up to 98
Number of operational channels, [pcs]	4
Operational channel volume, [m3]	0,56
Electric power, [kW]:
- magnetic system	30
- auxiliary equipment and ventilation system	5
Magnetic field strength, [A/m]	Not less than 0.6 x 10⁵
Number of magnetizing coils, [Pcs]	4
Weight of filtering packing, [kg]	~ 800
Weight of filter construction (without water), [kg]	~ 1200
Total weight of the magnetizing coils, [kg]	~ 800
Filter overall dimensions, [m]	1,6 х 1,8 х 2,5
Dimensions of the mounting pad, [m]	4,0 х 4,0
Filter lifetime, [year]	25