SI8711343A8 - Device for cleaning rotational regenerative heat exchangers - Google Patents

Description

PROCEDURE FOR CLEANING REVERSE REGENERATIVE HEAT EXCHANGERS

FIELD OF THE INVENTION

The invention falls within the scope of cleaning procedures, in particular rotary regenerative heat exchangers for transferring heat from a more heated stream of dirty gas to a lower heated stream of pure gas.

Technical problem

A technical problem to be solved by the process according to the invention consists in towers, how to accomplish a process for efficient cleaning of heat transfer surfaces of regenerative heat exchangers without significant increased energy consumption and negligible working time, especially for the heat exchangers affected by them. Pre-gaseous gases ^ containing Contaminant particles that tend to be separated and deposited on heat transfer surfaces, and the resulting solidified layer closes the passageways between the topiota transfer surfaces.

The state of the art

In order to sometimes clean the soiled, coated layers of impurities, the heating surfaces as well as the clogged passageways of the heat exchanger honeycomb, in the built-in condition, but without turning off the air preheater, and to dissolve the dissolved precipitate and impurities completely and safely from the heat exchanger honeycomb. according to the method of patent file DE-B 25 14 173, a series of cleaning nozzles is sprayed, which spray high pressure cleaning fluid,? and flushing nozzles that spray cleaning fluid at a lower pressure or with increased flow. ; the lashes are mounted on sliders that move relative to the plane of the heat exchanger, and within the sector above the front surface of the heat exchanger hub.

There is a known process for dissolving layers of deposited dust without the use of high-depth cleaning nozzles during the operation of rotary regenerative heat exchangers, as well as for flushing before the formation of the hardened primary layers and the secondary layers deposited therein.

the purpose of using a press, or a gas jet with a cleaning agent in

Intermediate nozzles or vapors are injected in the direction of flow from the nozzle so that a portion of the gas flowing around the rotary regenerative heat exchanger is drawn into the tube and mixed with the cleaning agent into directional jets. what is the equilibrium velocity at which the mixture is introduced into the inlet ducts between + the heat exchange surfaces in the hose of the CDE - B 26 15 4335. The suction process reduces the jet velocity in the passageways between the heat transfer surfaces which They are pure but increase mass flow to the same extent and achieve more intensive dissolution and evacuation with greater depth effect.

Consumers of energy for the industry, especially the automotive industry, are largely spray painting or lacquering plants. Suggest solutions for extracting heat from the exhaust air from the paint plant to heat the supply air did not give satisfactory results. The Cu spray mist fog separators5, which were placed in front of the heat exchanger, did not sufficiently protect the heat exchangers despite the very high separation rates of almost 99.9%. Reversible regenerative heat exchangers, as heat exchangers, have proven to be particularly vulnerable in this case, because of their construction they have very narrow passage channels where residual color particles from the air outlet stream are separated from the air outlet and in a short time lead to that the rotary regenerative heat exchanger is no longer functional. This also applies to other varnishing plants, the metal products industry and the furniture and furniture industry.

Description of solution to a technical problem

The invention is intended to provide a process for the effective cleaning of heat transfer surfaces of regenerative regenerative heat exchangers, without significantly increased energy consumption and negligible working time, especially for the heat exchangers affected by the gases fouled in the previous process, in which contain impurity particles that tend to be separated and deposited on heat transfer surfaces and the resulting solidified layer closes the passageways between the heat transfer surfaces.

Starting from the procedure described at the outset of the state of the art, this objective is achieved by having the heat exchanger rotor actuated to change the rpm speed and thereby achieve the low rpm required for cleaning as well as change the rpm depending on the slider position with nozzles between the hub and rotor sheath, and limit switches are installed to interrupt or change the direction of movement of the nozzle sliders. In this way, it is possible to achieve a procedure in which, by regulating the number of rotor turns depending on the position of the slider with nozzles, a constant speed of movement of the slider with nozzles will be achieved with respect to the surface of the heat exchanger hose, so that the nozzles will act on the annular surfaces on the blade of the manifold. Spread evenly with jets throughout the entire cleaning process.

For intensive cleaning, it is advantageous to attach a nozzle-slider drive to the drive of the nozzle slider by means of which the nozzle slider moves about the diameter of the cone formed by the jets striking the heat exchanger's hoses as soon as this cone closes at the front face of the honeycomb. at least one circular ring.

For some regenerative heat exchangers with a rotary shaft of the exchanger as with a rotor, and with a fixed connection duct, slider movement can be achieved without gap by means of a threaded spindle with the bearing having a bearing mounted on one transverse support and / or the housing wall, the spindle nuts connected with

L · a nozzle slider coupled to a drive threaded spindle, as well as one cleaning nozzle for hot pressurized water or for steam and / or pressurized air nozzles. In order to keep the flow of the heat exchanger gas in the cleaning duct as low as possible, it is convenient to place a collecting device for the outlet of the dissolved impurities together on the opposite side of the heat exchanger hose. with a cleaning agent.

In order to avoid the return of the cleaning liquid present in the collecting unit and the impurities drawn thereto, the edges of the elastic material may be installed on the inlet side of the collecting unit.

Particularly economical application of the cleaning agent is achieved by installing one connecting line that connects to the outlet for the cleaning agent of the collecting device and occasionally switching on by one device to remove mixed impurities, the purified cleaning agent returns to the supply tank.

Multiple use of the cleaning agent in a circular flow is made possible by the fact that a supply tank via a single line with a built-in pump is connected to a nozzle, or nozzles, for the cleaning agent.

It is advantageous to use pressurized air or water vapor as a gaseous cleaner. have the nozzles for the windshield wipers connected to a pressurized air source or steam generator. If the air source is pressurized, it is advantageous to use a pneumatic motor to drive the threaded spindle to drive the nozzle with the nozzle instead of adjusting its electric motor.

Alternatively one or more pneumatic cylinders can be connected to drive the nozzle slider and possibly the sump assembly.

It is advantageous for the spray nozzle to move at least one profiled element and to be provided with a twist.

This profiled element is in the form of a slotted tube comprising a threaded spindle or a piston rod of a pneumatic cylinder on the inlet side of the soiled gases, and providing a slit displaced with respect to the inlet side against the twist of the threaded spindle, or the connecting element between the slider and the threaded nut nut. , or piston rod, secures against twisting. The slit tube thus performs a double function: the function of guiding the slider with nozzles on the one hand, and the locking of the threaded spindle, or piston rod, of the pneumatic cylinder against the deposition of impurities contained in the gas stream, on the other.

The process of the invention is to reduce the rotational speed of the regenerative heat exchanger rotating parts, to clean the jet and sometimes the drying agents, continuously or stepwise, stepwise, radially, from the outside inwards and / or on the contrary, they spray on the front surface of the heat exchanger hub. In this way, in the inlet part of the passage channels between the heat transfer surfaces, the separated impurity particles are efficiently and simultaneously dissolved through the passageways for the heat exchange gases through the passageways for the heat exchangers. The process is to move the jets gradually or steadily by approximately the width of the area they normally fall into. To act on the honeycomb, when the rotating part of the regenerative heat exchanger moves by at least one full revolution.

The speed of rotation of the rotating parts of regenerative heat exchangers is scaled for uniform and safe loading, and the front surface * of the heat exchanger's eye is reduced by women to 0.1 to 0.3 g, preferably at 0.2 rpm.

For regenerative heat exchangers designed to transfer heat from waste air containing spray paint to fresh air supplied to a spray painting plant, it is used as a high-pressure hot water boiler, which is pressurized from 60 to 140 bar, most preferably 120 bar, and with a temperature of from 60 to 100 ° C, spray in the form of jets onto the front surface of the heat exchanger comb.

The heat exchanger hoses can then be dried with pressurized air between 3 and 8 bar.

Dissolving agents and / or inhibitors may be added to hot water, for example to prevent or reduce the corrosion of the heat exchanger hood sheets.

In order to shorten the time of cleaning and eventual drying, it is foreseen to treat the heat exchanger hoses first by radially moving the cleaning agent from outside to inward and then by radially moving the washing or drying jet from inside to outside, whereby cleaning and / or rinsing or drying may be repeated if necessary. Alternatively, the reverse order may be applied, or the flushing and drying nozzles may be brought directly behind the cleaning nozzles during the same radial motion.

A mixture of gaseous or liquid and solid, preferably powdered or granular, materials may be used as a cleaning agent to transfer the heat of the exhaust gases to fresh air supplied to a room or rooms.

The invention will be explained in more detail in the following description of two embodiments, with reference to the accompanying drawing, where:

- Figure 1 shows a partial sectional view of an apparatus for carrying out the process of the invention,

2 shows a partial sectional view of a modified embodiment of a device for performing the method of the invention.

Figure 1 shows a partial cross-section of a part of a rotary regenerative heat exchanger with a rotary actuator, with its blade 7 serving as a rotor. The nozzle 1 for drying and the nozzle 3 for cleaning are mounted on a common slider 5. The nozzles 1, 3 are shown stacked one behind the other with respect to only partially shown hose 7 of the heat exchanger. Line 11 feeds the nozzles 1 for drying the pressurized air, and line 31 nozzles 3 boil water from sources not shown. Slider 5 secures the threaded spindle nut Cnia shown? coupled to threaded spindle 13. Threaded spindle 13 is enclosed by a single profiled element in the form of an average IS pipe. The ends of the threaded spindle 13 are pivotally mounted in the bearings 17 and, to the radially outer end of the threaded spindle 13, a drive device 19 for steadily moving the slider

5. On the opposite side of the hatch 7 of the heat exchanger, and opposite the slider 5 with nozzles 1, 3, there is a collecting ol uk 20 with a drain 22 for discharge. At the inlet of the collecting gutter 20, the edges 24, 26 of the elastic material z are mounted obliquely backward, which open under pressure of the jet cleaning agents, thus preventing the return of the cleaning agent from the collecting gutter 20 towards the now 7 heat exchanger.

Figure 2 shows a modification of the collecting device in a slightly larger scale than Figure 1, in the form of a limited section. Of the drying and cleaning nozzles only the heads 51, 53 of the nozzles are shown in the drawing. On the other side of the nozzle 57 of the heat exchanger, one collector 59 is arranged opposite the nozzles in the form of a single funnel. The pickup assembly 59 is connected to the slider 65 via a retainer 63, which is shown by means of a threaded nut Cnia} coupled to a threaded spindle 67. The threaded spindle is protected by the surrounding gas stream through a profiled element 69, made in the form of a split tube, whereby this profile is profiled. element 69 is used to guide the slider 5, and a longitudinal slot provided therein provides the slider 5 from twisting. The threaded spindle 67 of the collecting device 59 is connected to the threaded spindle to move the nozzle slider 51, 53 shown more) mechanically so that the heads 51, 55 of the nozzle on one, and the collecting device 59 on the opposite side of the heat exchanger 57, synchronously move in common propulsion engine om.

The preceding description shows an apparatus for performing the cleaning procedure of regenerative heat exchangers with a poplar heat exchanger swivel and fixed conduits for currents of heat exchangers. The use of kinematically inverted heat exchanger designs, i.e., fixed-combustion heat exchangers and rotary heads as flares for gas throttles, is also possible, with the nozzles and the collecting device rotating together with the rotating heads on the front faces of the heat exchanger. In the first case, the heat exchanger combs should be viewed, and in the second case, on both sides of the comb, the synchronized rotary head as the rotating part of the heat exchanger, ie. like a rotor.

STATEMENT OF THE BEST. TO THE APPLICANT KNOWLEDGE. THE WAY FOR THE ECONOMIC

APPLICATION OF SUBMITTED FINDING

The commercial use of the present invention does not require any specific knowledge or experience. Only the knowledge of the average person skilled in the successful application of the invention is required and sufficient, based on the description of the invention.

In addition, the following should also be noted:

1. Given the relatively small thickness of the walls of the now heat exchanger, it is necessary to carry out the procedure described, and taking into account the small number of revolutions of the now heat exchanger CO, 1 to 0.3, optimum 0.2 min, in order not to exceed the maximum values pressure C140 bar? and temperature C100 ° 0. This should be done in such a way that either the temperature or the pressure of the CvodeJ cleaning agent is reduced in a single, experience-based measure.

2. In the case of pressurized air for drying the heat exchanger now, its pressure in practice should be S up to 6 bar, thus ensuring the condition for efficient and successful drying.

Claims (6)

PATENT REQUEST 1. A method for cleaning rotary regenerative heat exchangers for transferring heat from one more heated, soiled air stream to a less heated, clean gas stream, whereby the number of rotations of the turntable, hatch 7 of the regenerative heat exchanger can be reduced during cleaning, and jet cleaners are from nozzles 3; 53, 1; 51, with continuous or steady radial displacement of the nozzles on the slider 5; 65 from the outside inwards and / or vice versa, sprayed on the front surface of the comb 7; 57 of the heat exchanger, characterized in that the cleaning agent is brought to one end surface of the heat exchanger hose, and after passing through the honeycomb, together with the dissolved impurities, exits on the opposite face of the honeycomb face, and is then collected in the collector C20: 593. open to that surface of the honeycomb and positioned directly below the honeycomb radially in the direction of the nozzles C3, 1; 53, 513, and drains. Method according to claim 1, characterized in that the rotational speed of the regenerative heat exchanger parts and the position of the jet cleaners and drying agents are changed so that the relative velocity between the areas affected by the jets on the front surface of the regenerative heat exchanger is maintained constant. j Method according to claim 1, characterized in that the jets are moved in a stepwise manner, approximately by the width of the area to which these jets act on the front surface of the heat exchanger hub, and when the rotational part of the regenerative heat exchanger performs at least one full revolution. The method of claim 1, wherein the rotational speed of the regenerative heat exchanger for cleaning is reduced to 0.1 to 0.3, preferably to 0.2 rpm. 5. The method of claim 1 for transferring heat from the waste air containing the vapor of the dyes to fresh air introduced into the spray painting plant, spraying on the front surfaces of the heat exchanger hose - High pressure hot water, pressurized from 60 to 140 bar, preferably 120 bar, and temperature from about 60 to 100 ° C. A method according to claim 5, characterized in that the heat exchanger stops after drying with hot water jets of high pressure is dried by a pressurized air which is pressurized between 3 and 8 bar,