DD296337A5 - DEVICE FOR PRODUCING STEAM FROM HOT WATER BY RELAXING - Google Patents

Abstract

The invention relates to a device for generating steam from hot water by relaxation. It can be used anywhere where steam is needed continuously and hot water, z. B. from a district heating network, is available. The aim of the invention is a continuous steam generation with universal steam parameters, good thermal properties and any quantities. The task is to avoid an uncontrolled two-phase flow and water hammer during the direct feed and relaxation. According to the invention, a self-acting pressure regulator 2 is arranged directly at the connection of the feed line 1 to the expansion vessel 3, and the steam line 6 is provided with a pre-pressure regulator 7. Figure {Steam Generation, Continuous; Heiszwasser; Entspannungsgefaesz; Feed, directly; Relaxation; Wasserschlaege; Pressure regulator; Pressure regulator; two-phase flow}

Description

For this 1 page drawings

Field of application of the invention

The invention relates to a device for generating steam from hot water by relaxation. It can be used wherever steam is needed continuously and hot water, ζ. B. from a district heating network, is available. These are in particular production facilities that require smaller amounts of steam and where steam generation by means of primary energy sources is not worthwhile.

Characteristic of the known state of the art

For fossil fuel heat generation, large plants represent the most environmentally friendly and energy-efficient option. However, the centralization of heat generation necessitates extensive networks for district heating and requires the choice of a heat transfer medium that has a high degree of transportability. Hot water has the advantage over steam. But there are heat consumers who rely on steam for technological processes.

It's commonly known. Generate steam from hot water indirectly by means of heat exchangers. The advantage here is the continuity of steam generation and the low by the separation of the circuits impairment of the water quality of the district heating system. Disadvantages are the high plant costs and the limits of the steam parameters set by the functionally necessary temperature difference.

Another solution for providing smaller amounts of steam, regardless of time and place of production, are down-dip tanks. However, a steam generator must be present in the vicinity of the consumer. Disadvantages are the large storage mass and the correspondingly large memory space or space requirement.

The steam generation by relaxing hot water in a flash vessel has long been known. For example, DRP 126622 uses two vessels partially filled with water, whereby the steam in the first vessel is generated by feeding and relaxing hot water of higher pressure by means of a nozzle. The unevaporated water is subjected to a higher pressure in a second vessel and then heated in a firing room. Via a valve and the mentioned nozzle, it returns to the first-mentioned expansion vessel.

The injection of the pressurized hot water into the expansion vessel already creates strong hydraulic loads in the flow line and the actuators arranged there.

The pressure reduction in the expansion vessel causes a partial pressure reduction in the upstream parts, so that there forms an undesirable two-phase flow with a correspondingly high noise and mechanical stress.

In DRP 284403 an intermediate container for separating vapor bubbles from the hot water is therefore arranged in front of the expansion vessel. However, this separation device requires a further container and additional connections, without in any case, in particular not with more severe demands on the steam parameters, the said hydraulic loads can actually be avoided.

The relaxation devices described so far are characterized in that the pressurized hot water in the flow line before the expansion vessel relaxed and then into the expansion vessel above the water level,

d. H. in an anhydrous space of this vessel is introduced. The pressure relief takes place in the flow line, which causes the formation of a two-phase flow.

In contrast, WP 267546 and WP 267547 are based on the idea of allowing a gradual release of pressure in the expansion vessel. The expansion vessel is therefore an upright standing filled with a water column pressure vessel in which the hot water supply is well below the water level. Thus, the water column in the expansion vessel is pressure-increasing between the actual expansion pressure (vapor pressure) and the connection of the flow line. In the flow from bottom to top then a gradual vapor bubble formation is possible.

The WP 267546 and the WP 267547 require due to the water columns in the expansion vessels in their realization large heights.

The resulting construction cost represents a significant disadvantage and often excludes the installation of the device in existing buildings.

In addition, great demands are placed on the pressure and temperature control.

Object of the invention

The aim of the invention is to ensure in steam generation from hot water, especially from district heating networks, a continuous steam generation with universal steam parameters, good thermal properties and any amounts in trouble-free operation, the cost of equipment and structural shells should be low.

Explanation of the essence of the invention

The invention has for its object to avoid in a device with direct feed and relaxation of hot water to generate steam generated by an uncontrolled two-phase flow water hammer and thereby to dispense with the interposition of a water column.

The object is achieved in a device with connection of the hot water supply via a relaxation valve in the anhydrous room of a flash tank, steam removal at the head and return removal at the bottom of the flash tank, that the expansion valve is located directly on the flash tank. The expansion valve is preferably designed as a self-acting Nachdruckregeier, while the steam line is provided with a form control.

The return drain discharges into a switching column with free water level and is equipped with a control valve. The arrangement of the expansion valve directly on the flash vessel, in contrast to the prior art, the forming water-steam mixture is introduced as a free jet and has no flow path in the flow line. This will prevent water hammer.

embodiment

The invention will be explained below with reference to an embodiment with reference to the accompanying drawings:

The hot water is fed via the flow line 1 and the pressure regulator 2 to the flash vessel 3.

The resulting after relaxation water-steam mixture is deflected by the baffle plate 8 in the expansion vessel 3 down. The resulting in the flash evaporation steam (about 10% of the hot water mass flow) is dehumidified in the liquid 11 and passes in the upper part of the expansion vessel 3 via the admission pressure regulator 7 in line 6 to the consumer.

The post-pressure regulator 2 limits the vapor pressure in the expansion vessel 3 to a maximum value, that is, the hot water supply is throttled.

The admission pressure regulator 7 opens upon reaching a specified minimum vapor pressure and serves to limit the maximum

Steam water flow and thus to ensure the desired steam quality.

The non-evaporated hot water (about 90% of the hot water mass flow) is derived below from the expansion vessel 3 and fed by means of the return pump 4 via the control valve 5 of the return line 10.

In the switching column 9, a free water level is formed (i.e., not in the flash tank 3). Depending on a fixed water level, the control valve 5 determines the flow rate of the return pump. 4

Claims (3)

1. A device for generating steam from hot water by relaxation with connection of the hot water supply via an expansion valve in the anhydrous room of a flash vessel, steam removal at the head and return removal at the foot of the flash vessel, characterized in that the expansion valve (2) is arranged directly on the expansion vessel (3) , 2. Apparatus according to claim!, Characterized in that the expansion valve (2) is designed as an automatic pressure regulator and the steam line (6) is provided with a pre-pressure regulator (7). 3. Apparatus according to claim 1, characterized in that the return removal (10) with a switching column (9) with free water level and a control valve (5) is provided.