RU33428U1 - Gas-water heat exchanger with protection against low temperature corrosion on the gas side - Google Patents

Description

The utility model relates to heat exchange technology and can be used in hot water boilers, industrial hot water recovery boilers, gas condensate heaters, network and make-up water of recovery boilers installed behind gas turbines and diesel engines, etc. to protect gas-water heat exchangers from low-temperature corrosion on the gas side, resulting from condensation of water vapor contained in flue gases at a cold heat exchange surface, at rated power, and also to provide a given law for changing the temperature of water at the outlet of the heat exchanger with a decrease in its thermal power.

Known gas-water heat exchanger containing a heat exchange surface, a supply pipe to the cold water heat exchanger and a means of increasing the temperature of cold water at the inlet of the heat exchanger to a value exceeding the dew point of water vapor in the heating gases 1 analogue. The means for increasing the temperature of cold water at the inlet to the heat exchanger according to 1 is made in the form of a recirculation pipe equipped with a pump connecting the hot water outlet of the heat exchanger with a cold water pipe. The heat exchanger is a water boiler equipped with an economizer included in the recirculation circuit, and the recirculation pipe of the water heated in the boiler is connected to the input of the water economizer.

The disadvantages of the well-known heat exchanger 1J are the need for a larger capacity recirculation pump, significant energy costs and the creation of the recirculation flow required to heat the water entering the boiler to a temperature that is safe under conditions of low temperature corrosion.

A gas-water heat exchanger closest in purpose and effect is known, comprising a heat exchange surface divided into at least two sections connected in series through the water, a cold water supply pipe to the first section, a bypass pipe for mixing cold water in cascade to all other sections, and means for increasing the temperature of cold water at the inlet to the first of the mentioned sections to a value exceeding the dew point of water vapor in the heating gases 2 — prototype. The means for raising the temperature of cold water according to 2, as in 1, is a recirculation pipe equipped with a pump. By reducing the amount of recirculated water as a result of mixing cold water into all sections of the heat exchange surface, technical solution 2 allows to reduce the energy consumption for recirculation, but cannot completely eliminate the need for a recirculation pump ..

The achieved result of the utility model is the complete elimination of the need for a circulation pump with the corresponding complete elimination of capital costs for its purchase and operational energy costs for pump drive.

Obtaining this result is ensured by the fact that in a gas-water heat exchanger containing at least divided by

two sections connected in series through the water, a heat exchange surface, a cold water supply pipe to the first section, a bypass pipe for mixing cold water in a cascade scheme into all other sections, and means for raising the cold water temperature at the inlet of the first of the said sections to a value exceeding the water dew point vapor in heating gases, according to a utility model, said means is made in the form of a cold-water pre-heater of cold water connected via a heating medium to the outlet of hot water from the ice section of the heat exchange surface.

The drawing shows, by way of example, a circuit for switching on a hydrous-water heat exchanger (gas condensate heater) according to the user model for the heated side (for water) and the heating side (for gas).

The heat exchanger in a particular case contains four pipe sections 1.1, 1.2, 1.3, 1.4 of the heat exchange surface, connected in series through water by lines 2 of the main condensate stream and washed in parallel with a flue gas stream 3, a cold water supply pipe 4 to the first section 1.1, a bypass pipe 5 for mixing cold water in a cascade scheme to all other sections 1.2-1.4 and a means of increasing the temperature of cold water at the entrance to the first section 1.1 to a value exceeding the dew point of water vapor in the heating gases (in this example, 60 ° C, moreover, the said means is made in the form of a water-water pre-heater 6 of cold water, connected through a heating medium with agnium 7 to the outlet of hot water from the last section 1.4 of the heat exchange surface, and through the heated medium into the dissection of the piping 4 supply of cold water to the first section 1.1. and 5 are connected to a common iodine pipe 8 of cold water, equipped with a pump 9.

The operation of the gas-water heat exchanger according to the utility model is carried out as follows. With pump 9, cold water (condensate) is pumped through line 4 to preheater 6, after KOiopOi g narpe L, until it is safe in terms of corrosion (in this example, up to 60 ° C), sleep goes to the input of the first section D.1 of the heat exchange surface of the gas condensate heater. After passing successively sections 1.1-1.4 of the heat exchange surface of the heater, hot condensate is supplied as a medium to the preheater 6, after cooling in which it reaches the consumer. Part of the cold condensate through pipeline 5 is cascaded into the inlet of each oeiv TsIY1.2-1.4 in a cascade circuit.

Thus, according to a utility model, the condensate is heated throughout the tract by a predetermined value the temperature of the dew point of the water vapor in the flue (heating) gases, which ensures: rm protection of the heat exchange surface from low-temperature corrosion on the north-west side without the need for recirculation clock This reduces energy consumption and increases the reliability of the heat exchanger.

Sources of information:

1. USSR Certificate of Authorship No. 1390489, 4 F24H 1/00, 1986. 2.3. Application No. 2003111636 of 04.25.2003 for the issuance of a RF pagent for a utility model

Claims (1)

A gas-water heat exchanger comprising a heat exchange surface divided into at least two sections connected in series through water, a cold water supply pipe to the first section, a bypass pipe for mixing cold water in a cascade circuit to all other sections, and means for raising the cold water temperature at the inlet to the first the said sections to a value exceeding the dew point of water vapor in the heating gases, characterized in that the said tool is made in the form of a water-water pre-heater water, connected by a heating medium to the outlet of hot water from the last section of the heat exchange surface.