DE1138795B - Arrangement for regulating the final temperature of the working medium of a heat exchanger, in particular a once-through steam generator, made up of several heating surface groups connected in series and heated by means of gaseous means - Google Patents

Description

GERMAN

PATENT OFFICE

M33382Ia / 13g

NOTICE DATE: FEBRUARY 27, 1957

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: OCTOBER 31, 1962

In the case of heat exchangers that are heated by a gaseous medium, in particular once-through steam generators, it is known to divide the heating surfaces of the heat exchanger into contact and radiant heating surfaces in order to be able to use different Loads to keep the final temperature of the working fluid at a certain setpoint. There Radiant and contact heating surfaces have opposite temperature characteristics, i.e. that the The temperature characteristic of the radiant heating surface increases with decreasing load and that of the contact heating surface decreases, the overall characteristic can be adjusted of the heat exchanger are evened out.

In a known natural circulation steam generator with one in a radiant heating surface and one The superheater divided into contact heating surfaces is intended to keep the final temperature of the steam constant be that by means of swiveling burners the heat supply in favor of one when the load changes or another heating surface is relocated.

Also known is a natural circulation steam generator in which the superheater is in two groups of heating surfaces is divided, with each heating surface group of two acted upon with a partial flow of the working medium Consists of heating surfaces. By means of a temperature sensor at the outlet of the last heating surface groups a controller is influenced, which allocates to each heating surface of the group an amount of working medium measured according to its heat load, so that the Working fluid emerges from both heating surfaces at the same temperature. Keeping the final temperature constant of the working medium is achieved in that a superheated steam cooler between the heating surface groups is switched on, to which, depending on the final temperature, a corresponding partial amount of the working medium emerging from the heating surfaces of the first group is supplied.

With the two known steam generators, temperature control is only required for one group of heating surfaces performed. Both steam generators have the disadvantage that the active ingredient of the first or single heating surface group designed for the highest temperature of the respective characteristic must be what either high-quality material or an enlargement of the heating surfaces and thus higher pressure loss due. Furthermore, the arrangement of a separate superheated steam cooler represents a Additional effort.

The invention relates to an arrangement of a plurality of heating surface groups connected one behind the other built up, by means of a gaseous arrangement to regulate the final temperature of the working medium one of several

interconnected heating surface groups built up by means of gaseous media

heated heat exchanger, in particular a once-through steam generator

Applicant:

Machine factory Buckau R. Wolf

Aktiengesellschaft, Neuss / Rhein, Aachener Allee 6

Dipl.-Ing. Wolfgang Kalide, Neuss / Rhine, has been named as the inventor

Means of heated heat exchanger, in particular a once-through steam generator, for regulation the final temperature of the working medium, at which each group consists of at least two connected in parallel Consists of heating surfaces. The invention avoids the disadvantages of the known steam generator in that within each group, the heating surfaces connected in parallel in a manner known per se, partly radiation and are partly contact heating surface and that the working medium flow on the one hand to the contact and on the other hand, it is divided into the radiant heating surface of each group in a manner known per se, that for each group the temperatures of the working medium at the outlet of the two heating surfaces are the same are high.

The mixing and removal of the partial quantities from the heating surfaces connected in parallel can thereby take place that the partial quantities after exit from the heating surfaces in a connected to the discharge line Vortex head are conducted in which the partial flows initially parallel independently of each other out and then mixed with one another with opposite twist.

An advantageous embodiment of such a mixer according to the invention is that in the the discharge line connected to one heating surface, the discharge pipe connected to the other heating surface is introduced concentrically leaving an annular gap and in this and the latter

209 679/57

Discharge line vortex plates are used, the partial amount of which corresponds to the heat absorption The direction of twist is opposite, in which case it is advantageously supplied.

halter way behind the vortex plates of the Innenroh- The invention is shown schematically in the drawing

res an insert body is provided, which shows this from and that shows:

directs flowing medium outwards. 5 Fig. 1 the circuit diagram of a steam generator,

The arrangement according to the invention has the advantages Fig. 2 a mixing head in vertical section,

part that each heating surface no longer has a certain, Fig. 3 a section in the direction III-III of the

but according to the different Fig. 2.

Flow rate an infinite number of characters In Fig. 1 are the three superheater stages 1, 2 and 3

features. Represented from each of these infinitely many io of a steam generator. Each superheater characteristic is divided by the parallel connection of stage is into a radiant heating surface S ₁ or radiant with contact _{heating surface and by the S 2} or S ₃ and a contact heating surface B ₁ or B ₂ distribution of the flow rate depending on or B _s , which are always connected in parallel to the temperature heater stage in the steam flow within each Above the outlet temperature. The set at the steam point, which represents the optimum of the currently dangerous generator generated total amount of steam flows the ren load for the heating surface in question. first superheater stage 1 from a manifold α Over the entire load range, this is optimal over a rotary valve D ₁ , which serves to keep the temperature approximately the same, so that the material incoming total amount of steam on the radiation of the heating surfaces no longer for the overtemperature heating surface S ₁ and the Touch heating surface B ₁ needs to be laid out. 20 assign. In order to achieve this, each heating surface is only to be designed for one heating surface S ₁ , B ₁ , a subset of the maximum output T _{1 a} , so that T _lb , both the measured values on one the number of parallel strands in this heating surface A , controller R _{1 of} known design. In the smaller and the Temperaturverteihing in the strands controller R ₁ , the two temperatures are mitekibetter. 25 other compared and with temperature differences The invention offers further advantages in that the rotary valve D _{1 is} adjusted, so that each of the two steam generators with two radically different heating surfaces S ₁ , B _{1 have} a correspondingly sized fuel, such as. B. coal and furnace gas is individually allocated to partial steam flow. Heated according to this or in any quantity ratio, partial flow amount is the outlet temperature of the no temperature influence of the end temperature 30 both heating surfaces S ₁ , B ₁ so long influenced until it occurs when when switching off one of the two have assumed the same value. Behind the types of fuel, the main heat output from the temperature measuring elements, the partial quantities emerging from the radiation into the contact part of the steam generator heating surfaces S ₁ , B _{1 are} shifted or vice versa, because the vortex sensor M ₁ then immediately mixes with one another again. relocated to the loading and the subsequent superheater stage 2 in the stirrer heating surface, or vice versa. fed in the same way. Corresponding reference

Since the temperature symbol always applies to all heating surfaces.

turoptimum set for the load being driven

there is also an optimum of heat _{and vapor components of the radiation part S 1} and the use of the surface, which is expressed in the fact that the 40 rungsteües B ₁ to avoid streaking of the exhaust gas temperature of the steam generator over the load by turbulence on the shortest path approximately can be constantly mixed at the lowest possible level. In addition, a lower value should remain in the mixing head. Different outlet pressures of the parallel manifolds from and to the individual heating surfaces, which when the flow-through heating surfaces change, have a smaller cross-section and thus set a 45-minute rate, lower wall thickness and lower overall, in order to promote mixing. In order to achieve material consumption than the previously required collection, this is, for example, the outlet lines, which had to be designed for the entire amount of the maximum line b of the radiation part S ₁ with the discharge capacity. tube α directly connected, while the outlet The main collecting lines for the entire passage c of the contact part B ₁ concentrically under flow between a mixing point behind leaving an annular gap d in the outlet pipe a divided heat exchanger and the redistribution is guided. At the end of the outlet line c, upstream of the next divided heat exchanger, vortex plates e and a concentrically arranged insert leading to the outside as short as the steam flow due to the installation of a vortex mixer head are kept as possible in order to save material. 55 seen. Likewise, in the annular gap d at When starting up the steam generator provide the angeordparallele in the end of the exhaust pipe c swirl vanes g radiation and heating surfaces up net, whose direction of twist, however, the divided heat exchanger opposite the advantage that the swirl direction of the swirl vanes e. Furthermore, at the main flow, the flow rate is always shifted to the point where the two steam heating surface parts meet, which momentarily the 60 flows in the outlet tube α has a protective tube h for the greatest heat absorption. This can go so far, the wall of the outlet pipe α is provided that the entire start-up quantity can only be reached by the jet. The idea of the invention applies very generally. It allows the heating surface to pass through, while only a minimal flow generator is applied to each heat exchange stage of a steam heating surface, be it a feed water supply, until it is also warmer (economiser) or an evaporator or heating surface has a larger one Heat absorption takes place, superheater or an intermediate superheater or even what is only a part of one of the named heat noticeable by increasing the outlet temperature, whereupon this heating surface exchanger too, provided the condition that this is fulfilled

Stage is built up from several 'successively connected heating surface groups and thus more than one distribution point (D) and more than one mixing point (M) are provided.

It is possible to use each heating surface group of the heat exchanger not just in one radiant heating surface and to divide a touch heating surface, but it can just as well be divided into several parallel radiant heating surfaces and contact heating surfaces will.

The arrangement can be used in connection with steam generators of any type, e.g. Am Forced circulation or forced circulation or natural circulation steam generators, with the exception of the latter of the evaporation part.

The division of the partial quantities into the parallel heating surfaces can be done in the rotary valve already mentioned or by means of two or more control valves, one for each radiant or contact heating surface, take place.

Claims (3)

PATENT CLAIMS: 1. Arrangement of a built up of several heating surface groups in series, heated by means of gaseous means heat exchanger, in particular a forced flow steam generator, to control the end > temperature of the working medium, in which each group consists of at least two parallel heating surfaces, characterized in that within of each group, the heating surfaces connected in parallel are in a known manner partly radiant and partly contact surface and that the working medium flow is divided on the one hand to the contact and on the other hand to the radiant heating surface of each group in a known manner so that the temperatures of the Working medium at the outlet of the two heating surfaces are the same. 2. Arrangement according to claim 1, characterized in that in the connected to the one heating surface discharge line (a) connected to the other heating surface discharge line (c) is introduced concentrically leaving an annular gap (d) and in this and the last-mentioned discharge line vortex plates (g, e) are used, the direction of twist is opposite. 3. Arrangement according to claim 2, characterized in that behind the vortex plates of the Inner tube an insert body (/) is provided, which directs the outflowing medium to the outside. Considered publications:
German Patent Nos. 911 264, 767 278;
French Patent No. 758 288;
U.S. Patent No. 2109,840. 1 sheet of drawings © 209 679/57 10.