RU2619010C2 - Method of heat-power equipment cleaning from deposits and scale and device for its implementation - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: in contrast to the prototype, in the method consisting in pumping the cleaning solution through pipelines and internal cavities, before cleaning the system is emptied from working fluids, two washing solutions are prepared - alkaline, containing SAA, and acidic, solutions are heated up to 320…360K, are pumped alternately, starting with the alkaline solution, through the pipelines and internal cavities of the equipment. The solutions pumping alternates with the pumping of a neutral liquid, for example, water. The device includes pipelines, taps or valves, containers, pumps and is additionally equipped with two containers for cleaning solutions and a container with a neutral liquid, as well as a generator of pressure pulsation and speed.

EFFECT: improved cleaning quality.

19 cl, 1 dwg

Description

The group of inventions relates to a power system and can be used for chemical cleaning of power plant systems and technological equipment, in particular, cooling systems for internal combustion engines, heat exchangers, foundry equipment, and is intended to increase their reliability.

It is known that during the long-term operation of liquid cooling systems for ship power plants, internal combustion engines, heat exchangers, foundry equipment (molds, chill molds, molds), scale and deposits form in pipelines and channels (see Ivanov B.N., Ponomarenko V.M. Operation of ship diesel engines. M.: Transport, 1982. P. 156 - 162).

Scale and deposits have thermal conductivity coefficients tens of times less than the thermal conductivity of metals. As a result of this, the heat transfer rate is significantly reduced, the heat balance is violated and the temperature of the working surfaces rises (Surin S.M. Preparation and quality control of water for ship power plants. M.: Transport, 1978. - 152 s).

Overheating in internal combustion engines leads to increased fuel consumption, lower power, and worse lubrication conditions and can cause engine failure (Moiseev A.F. Prevention of scale formation in automobile engines. M.: Transport, 1971. - 128 s).

Violation of the calculated (optimal) temperature regime of a metal casting mold, for example for casting a block or cylinder head of an engine, as a result of the formation of deposits can cause casting defects such as loosening, sinks, shrinkage porosity due to slower cooling of the castings.

The listed disadvantages can be eliminated by providing the required (established) thermal regime. To achieve this goal, a method and device for descaling and deposits of liquid cooling systems of marine power plants, internal combustion engines, foundry equipment and other heat exchange equipment.

Analysis of the information selected in the search process revealed the method RD 31.28.53-79 “Chemical methods for cleaning ship equipment”, which is the closest analogue of the claimed solution to the technical nature and selected as its prototype.

The disadvantages of this method are:

- low cleaning efficiency;

- corrosion of equipment when using acidic cleaning solutions.

A device is known for protecting and cleaning ship diesel engine cooling systems (Circulation pump and tank system. Product information. Chemical products and technical services to shpping and industry. VECOM, Holland, 1990).

It has the following disadvantages:

- it is intended only for cleaning the internal and external diesel cooling circuits, which is achieved by increasing the circulation rate of the washing solution, and during the operation of the vessel, and not its repair;

- does not provide passivation of the surfaces of pipelines, tanks, etc., not included in the cooling system, which causes intense corrosion of these surfaces.

The technical result from the use of the claimed technical solutions is to improve the quality of cleaning closed heat and power systems from deposits and scale.

To achieve the specified technical result, the following set of essential features is used:

In the method of cleaning heat and power equipment from deposits and scale, which, like the prototype, consists in pumping the washing solution through pipelines and internal cavities, unlike the prototype, before cleaning the system empties the working fluids, two washing solutions are prepared - alkaline, containing surface-active ( Surfactant) substances, and acidic, heat solutions to 320 ... 360K and pump them alternately, starting with an alkaline solution, through pipelines and internal cavities of the equipment, while pumping alkaline and acid solutions are alternated with pumping a neutral liquid, such as water;

after 0.5 ... 3 hours of shaking the surfactant-containing solution, the system is emptied, washed with water until the pH of the solution is 6-8, after which an acidic washing solution is pumped for 0.5 ... 3 hours;

while in the process of swaying, the washing solution is cleaned (filtered), and then heated to the initial temperature;

while pumping the washing solution is carried out in the pulsation mode of the flow rate and fluid pressure;

at the same time, pulsations of the velocity and pressure of the liquid are created due to its self-oscillations;

in this case, the liquid self-oscillations are of a cavitational nature;

The primary pumping of an alkaline surfactant-containing solution creates a protective film on the metal surfaces before acid cleaning, which prevents intense corrosion of the cleaned areas.

The proposed device for cleaning heat and power equipment from deposits and scale, including pipelines, taps or valves, containers, pumps, in contrast to the prototype, is additionally equipped with two containers for washing solutions and a container with a neutral liquid, as well as a pressure and speed pulsation generator;

at the same time, as a generator of pressure pulsation of the washing solution, a device is used that makes it possible to obtain self-oscillations (spring valve, cavitation generator, Venturi tube);

while the source of pulsation of the cavitation generator is a high-speed circulating screw centrifugal pump;

at the same time, cleaning devices are installed at the entrance to the containers for washing solutions, consisting, for example, of a strainer and a hydraulic cyclone;

 while containers (tanks) for washing solutions are equipped with heaters, for example, coil type;

while the device is equipped with devices for assessing the degree of contamination of the system and the quality of its flushing;

while as a device for assessing the degree of contamination, a differential pressure gauge is used;

in this case, a photocell is used as a device for assessing the quality of washing;

while the circulation pump, treatment device, oscillation generator and capacitance are made in the form of a separate, for example, a portable module;

while containers for washing solutions are equipped with heaters, for example, coil type;

however, the device is additionally equipped with an automatic flushing control system.

A device for flushing systems is performed by a separate mobile or stationary module (depending on the conditions of use).

The inventive method and device allows to obtain a new technical result compared to the prototype, which consists in a better cleaning of closed systems from deposits and scale.

A comparison of the proposed method and device and their prototypes showed that the task is solved as a result of new sets of features, which proves the conformity of the proposed inventions with the criterion of "novelty."

However, the information search carried out in the field of cleaning and washing closed cooling systems of power plants and foundry molds did not reveal solutions containing individual distinguishing features of inventions, which allows us to conclude that the claimed method and device meet the criterion of "inventive step".

The cleaning method is illustrated by the following example.

After 4-6 months of operation of the ship’s power plant or 5-10 thousand fillings in a cooled metal form (depending on the quality and chemical composition of the used cooling water), the closed cooling circuit is disconnected from the centralized (workshop) water supply system and connected to the flushing module. The washing solution heating system is turned on. Heating can be carried out using water or steam coil heaters or electric heaters.

After reaching the temperature of the washing liquid 320 K, the circulation pump is switched on and the alkaline surfactant-containing washing solution is pumped through the water cooling system.

As a washing solution, for example, Ankras solution TU 3840820-78 (B. G. Bedrik, P. V. Chulkov, S. I. Kalashnikov. Solvents and compositions for cleaning machines and mechanisms. M: Chemistry. - 1989) or additives for auto No. 1317915, 1987; No. 1609120, 1990) at a concentration of 0.1 ... 5%.

Due to the low surface tension, the washing solution penetrates into the smallest gaps and cracks between the particles of contaminants and, adsorbing on these particles, creates a proppant that crushes and tears them apart. The same phenomenon of adsorption is due to the stabilizing and foaming ability, which keeps the particles of impurities in suspension and contributes to their removal from the surface being cleaned.

The high quality of surface cleaning is ensured by the combination of the Rebinder effect, which consists in reducing the mechanical strength of deposits under the influence of surfactant molecules (1. Goryunov Yu.V., Pertsov N.V., Summ VD. Rebinder effect. M. 1966. 2. Telnov A .F., Kozlov Yu.S. et al. Detergents, their use in mechanical engineering and regeneration. M.: Mechanical Engineering, 1993. - 208 p.) And chemical cleaning with acid solutions.

The cleaning solution contains corrosion inhibitors that provide a protective film on the metal surface and prevent corrosion of the cleaned areas when the acid solution sways.

Then the liquid passes through the cleaning device and again enters the tank, where it is heated to the initial temperature.

After thirty minutes of pumping the alkaline washing solution, the circulation pump is turned off, the closed cooling system is emptied by gravity, after which the acid washing solution begins to pump through it, which has a chemical effect on deposits that are loosened and partially destroyed. After the cooling circuit, the solution also passes through the cleaning device and enters the tank, where it is heated.

Pumping of the acid solution is also carried out from 0.5 to 3 hours, depending on the degree of contamination of the cavities and the nature of the deposits. Then the system cleaning cycle can be repeated.

Pumping of washing solutions is carried out with pressure pulsations, which are achieved by using a pressure reducing valve that opens when the liquid pressure reaches a certain value.

Pressure pulsation can also be cavitational in nature.

In this case, the source of self-similar oscillations is a cavitation generator or a device such as a venturi.

An increase in the fluid velocity in a narrow section of the venturi causes a drop in local static pressure. A gradual increase in fluid flow leads to a decrease in pressure to a critical pressure equal to or close to the pressure of saturated vapor and the occurrence of cavitation. The energy supply to the oscillatory system in this case is due to a change in the total pressure loss due to the sudden expansion of the flow behind the cavitation cavity. If the energy supply exceeds its dispersion at hydraulic resistances, then oscillations with increasing amplitude will be observed in the system. Nonlinear dependences of the total pressure loss on the sudden expansion of the flow on the size of the cavitation cavity and flow rate at the outlet of the venturi, as well as the nonlinear dependence of the hydraulic resistance of the system behind the venturi on the flow rate at the outlet of the tube, limit the amplitude and establish self-oscillations in the system behind the cavitation venturi .

The mechanism of cavitation self-oscillations in a system with a venturi is also applicable to other cavitating elements with narrowing-expanding channels of local hydraulic resistances.

Cavitation self-oscillations can be excited in the hydraulic system without the use of additional devices directly by a high-speed screw centrifugal pump. Hidden cavitation, despite the existence of cavitation cavities in the flow part, does not significantly affect the static output parameters of the pump (pressure, power, efficiency), but leads to a change in the dynamic characteristics of the system and, under certain conditions, causes self-excitation of pressure and flow fluctuations in the system (V .V. Pilipenko. Cavitational self-oscillations. - Kiev: Naukova Dumka. - 1989).

Between pumping alkaline and acid detergent solutions, the system is flushed with a neutral liquid, such as water, which avoids the neutralization reaction between acid and alkaline solutions, reduces the consumption of detergent solutions and increases their service life.

A device for cleaning technical systems is illustrated in FIG. one.

The structure of the device includes: 1 - closed cooling circuit; 2, 3 - containers for storing washing solutions, respectively alkaline and acid; 4 - circulation pump; 5, 6 - three-way valves or valves; 7 - cleaner, consisting of a strainer - 8 and a hydraulic cyclone - 9; 10 - fluid pressure pulsation generator; 11, 12 - fluid heaters; 13, 14, 15, 16, 17, 18, 19, 20, 21 - pipelines (hoses); 22 - capacity for discharge of pollution; 23, 24 - pressure gauges; 25.26 - thermometers; 27 - pipeline (hose); 28 - tap or valve; 29 - photocell; 30 - automatic control device; 31, 32 - three-way valves or valves; 33 - capacity; 34 - pipeline (hose); 35 - suction line of the pump.

The device operates as follows. Before flushing, the engine or mold cooling system is disconnected from the centralized (workshop) water supply system. The cooling system is emptied and connected via fittings to the piping 16 and 17 of the flushing module. A surfactant-containing washing solution heated to the required temperature by the heater 11, from the tank 2 through a pipe 13, through a three-way valve or valve 6 and a pipe 15 is supplied to the circulation pump 4. The circulation pump 4 pumps the washing solution through a fluid pressure pulsation generator 10 through the pipe 16 into the cooling system. After passing through the cooling system, the washing solution is discharged from the mold 1 through a pipe 17 to a treatment device 7, where washed mechanical particles are removed from it using a filter 9 and a hydrocyclone 8.

The purified solution through pipeline 20 through a three-way valve or valve 5 is returned to the tank 2 and heated in it to the rated temperature (320 ... 360 K) and again goes to the circulation pump 4. When pumping a surfactant-containing washing solution on the cleaned metal surfaces, a protective film is created before pumping the acid solution.

After 30 minutes of operation, the circulation pump 4 is turned off, the cooling system is emptied by gravity, the valve (valve) 31 is moved to the position communicating the hydrocyclone 8 with a capacity 33 filled with a neutral washing liquid, such as water. Through the pipe 34 and the three-way valve (valve) 32, the tank 33 communicates with the suction line of the circulation pump 35, while the line 35 is disconnected from the pipe 15. The pump 4 is turned on and the system is flushed with neutral liquid (water) for 5 minutes.

After washing with a neutral liquid, the taps (valves) 31 and 32 are switched to the positions that exclude circulation through the tank 33 and the pipeline 34, the taps (valves) 5 and 6 are moved to the positions in which the acidic washing solution is supplied to the circulation pump 4 from the tank 3 by pipe 14 through the tap (valve) 5 and pipe 15. After passing the cooling system of the mold 1 and cleaning in the filter 9 and hydrocyclone 8, the washing solution through pipe 20, through the tap (valve) 5 and pipe 19 returns to the tank 3, where at help heater I 12 is heated to the rated temperature (320 ... 360 K) and again enters the pump 4.

Washed pollution products are discharged from the hydrocyclone through line 21 to a container 22, which is emptied as it is filled through line 27 and a valve (valve) 28.

Manometers 23 and 24 are used to determine the pressure loss in the cooling system and assess the degree of its contamination. Pressure gauges corresponding to a clean cooling system are a signal to stop flushing.

The degree of purity of the system is also controlled by the turbidity (optical density) of the removed washing solution using a photocell 29.

Rinsing stops when the optical density of the washing solution corresponds to a predetermined value.

The flushing module is controlled manually or automatically using a special device (ACS) 30 that receives signals from pressure gauges 23, 24, thermometers 25 and 26, a photocell 29, a timer and controls the operation of the circulation pump 4, taps (valves) 5 and 6, and heaters 11 and 12.

After washing, the circulation pump 4 is turned off, the cooling system 1 is emptied by gravity, disconnected from the washing module and connected to a centralized water supply system.

Thus, as a result of the use of the proposed inventions due to the use of two washing solutions and pulsation of the pressure of the washing liquid, a high quality of cleaning is achieved, which allows to increase the resource and provide the calculated thermal regime of ship power plants or water-cooled foundry molds, which in turn ensures optimal heat removal in cooling system, protecting the system with substances having high inhibitory properties and a long lasting aftereffect, reducing repair costs.

The present invention was created by specialists of the Department of Theory and Design of Marine ICE FSBEI HE "State University of the Sea and River Fleet named after Admiral S.O. Makarova "as part of research work. Calculations were made that showed the possibility of using the claimed inventions, which, taking into account the foregoing, allows us to conclude about the possibility of their industrial application.

Claims (19)

1. A method of cleaning heat and power equipment from deposits and scale, which consists in pumping the washing solution through pipelines and internal cavities, characterized in that before cleaning the system is emptied of working fluids, two washing solutions are prepared - alkaline, containing surfactants, and acid, solutions are heated to 320 ... 360K, pumped alternately, starting with an alkaline solution, through pipelines and internal cavities of the equipment, while pumping solutions alternate with pumping neutral hydrochloric liquid such as water. 2. The method according to p. 1, characterized in that after 0.5 ... 3 hours of pumping a surfactant-containing solution, the system is emptied, washed with water until the pH of the solution is 6-8, after which an acid detergent is pumped for 0.5 ... 3 hours solution. 3. The method according to any one of paragraphs. 1, 2, characterized in that in the process of pumping the washing solution is cleaned (filtered), and then heated to its original temperature. 4. The method according to any one of paragraphs. 1, 2, characterized in that the pumping of the washing solution is carried out in the pulsation mode of the flow rate and fluid pressure. 5. The method according to any one of paragraphs. 1, 2, characterized in that the pulsations of the velocity and pressure of the liquid create due to its self-oscillations. 6. The method according to any one of paragraphs. 1, 2, characterized in that the self-oscillations of the liquid are cavitational in nature. 7. A device for cleaning heat and power equipment from deposits and scale, including pipelines, taps or valves, containers, pumps, characterized in that it is additionally equipped with two containers for washing solutions and a container with a neutral liquid 8. The device according to p. 7, characterized in that it is additionally equipped with a generator of pressure pulsation and speed. 9. The device according to any one of paragraphs. 7, 8, characterized in that a cavitation generator is used as a pulsation generator. 10. The device according to any one of paragraphs. 7, 8, characterized in that a venturi is used as a pulsation generator. 11. The device according to p. 9, characterized in that the pulsation source of the cavitation generator is a high-speed circulating screw centrifugal circulation pump. 12. The device according to any one of paragraphs. 7, 8, characterized in that at the entrance to the tank for cleaning solutions installed cleaning devices. 13. The device according to p. 11, characterized in that the treatment device is made of a strainer and a hydraulic cyclone. 14. The device according to p. 7, characterized in that the containers for washing solutions are equipped with heaters, for example, coil type. 15. The device according to claim 7, characterized in that it is additionally equipped with devices for assessing the degree of contamination of the system and the quality of its flushing. 16. The device according to p. 14, characterized in that as a device for assessing the degree of contamination, a differential pressure gauge is used. 17. The device according to p. 14, characterized in that a photocell is used as a device for evaluating the washing quality. 18. The device according to any one of paragraphs. 7, 8, characterized in that the circulation pump, treatment device, oscillation generator and capacitance are made in the form of a separate, for example, portable module. 19. The device according to claim 7, characterized in that it is further provided with an automatic flushing control system.

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