SU56084A1 - Method and device for steam cleaning in drum steam generators - Google Patents

Description

In MANY cases, the main reason for the deterioration of steam quality is foaming of boiler water. This foaming is promoted by increased dense residues (salt content) of boiler water and drastic changes in the flow in the steam generator.

To combat foaming under practical conditions, it is primarily necessary to reduce the salt content of the boiler water, to equalize the load curve, and, consequently, the vapor pressure fluctuations. However, these measures often turn out to be insufficient, and then one has to go on reducing the productivity of pfogenerators.

The operation of steam generators on high dense residues, if in some way eliminating foaming of the boiler water, is in all cases more effective in terms of cost. Thus, for example, in evaporators and dumping machines, increasing the dense residue of water reduces the percentage of blowdown, so it is possible to reduce the consumption of heat and chemically purified and raw water, and in some cases it is possible to increase the capacity of the installation. high dense residues of boiler water will also reduce the flow of purge water and switch to the power of chemically treated water. When feeding steam boilers with chemically cleaned water, there is no need to use evaporators at the stations, and this gives great economic benefits both on investment and in the operation of thermal power stations.

Therefore, it has already been proposed to perform steam cleaning by washing it with help of feed water, for which purpose the corresponding devices were placed inside the drum of the steam generator.

In the known schemes for the purification of steam of this kind from the salts carried away by the steam-flushing device placed in the steam volume of the drum, the feed water flows in the vertical direction of the Cr grid through which the steam passes. After draining from the nets, the feed water enters the water volume of the drum and mixes with large masses of circulating boiler water.

In contrast, the proposed method aims not to clean an already contaminated steam, but to prevent the possibility of steam contamination by moisture or from breaking foam bubbles (in the case of low foaming in the drum), or from direct entrainment of foam with steam from the drum (in the case of intensive foaming). and throwing water). In both cases, the destruction of foam bubbles occurs in the lower part of the vapor volume, i.e. on the evaporation mirror, and the destruction of steam from the burst; their bubbles are not moistened. This problem of foam destruction is solved, according to the invention, by uniformly supplying feedwater introduced into the drum to the evaporation mirror, i.e. above the water level in the drum, and this water acts on one side due to a lower salt concentration in it than with boiler water, and with another CTopOHbii, due to its lower temperature relative to the latter.

The feedwater is supplied to the evaporation mirror using special scouring troughs or trays located above the water level in the drum and covering the entire evaporation mirror, leaving small aisles, on the one hand, to drain the feedwater and, on the other hand, to exit stump in case of low water level, or the appearance of a throw in the drum.

In the drawing of Figs: 1 and 2, diagrams of two forms of the device for carrying out the method are shown.

In the embodiment of FIG. 1 number 4 indicates the fenders, playing the role of primary separators, in which there is a separation of the main mass of water from steam. Then steam with a small amount of trickle moisture and c. any number of pe: enters the space covered with sheets / type of trays, playing the role of a wash trough, into which feed water is supplied through distribution pipes 2, branched from common pipe 3. Digit 5 denotes a channel separator of coarse moisture, 6-separator of thin moisture , 7 drainage from the separator.

In the presence of feed water in the lower part of the vapor volume, the foam will inevitably collapse both due to a lower feed water temperature than the saturation temperature, which leads to condensation of steam inside the bubbles, their deformation and destruction, and due to a lower salt concentration of nutrient water than drop water, so that when a bubble is diluted with nutrient water, the strength of the shell decreases and it collapses.

The form of the device according to FIG. 2 differs from that of FIG. 1 only by the blasting device., /

The nutrient water enters the row of troughs / trays in which I have; T | SY horizontal, directed perpendicularly to the axis of the drum. From these gaps water is pulled out in the form of jets and overlaps the evaporation mirror, which at the same time can be closed with deaf and hard.

The rest of the device and the action is the same as in FIG. one.

The subject matter of the invention.

Claims (2)

1. A method of cleaning steam in drum Hbix steam generators using feedwater introduced into the drum, characterized in that the foam removed by steam through the primary separation devices is washed out with the aid of feed water supplied above the water level in the drum. 2. A device for carrying out the method according to claim 1, characterized by the use of trays / above the water level in the drum, to which feed water is supplied.