CN114893763A - Boiler feed pump sealing water structure behind condenser unit changes backpressure unit - Google Patents

Abstract

The invention provides a boiler feed pump sealing water structure after a condenser unit is changed into a back pressure unit, which can ensure the requirement of the oxygen content of feed water at the outlet of a boiler feed pump and improve the operation safety and the economical efficiency of equipment. The water inlet of the water inlet pipeline of the pre-pump is connected with the water outlet of the deaerator, and the water outlet of the water inlet pipeline of the pre-pump is connected with the water inlet of the pre-pump; the water inlet of the water inlet pipeline of the water feeding pump is connected with the water outlet of the front pump; the water inlet of the front pump sealing water inlet pipeline is connected with a sealing water inlet main pipe, and the water outlet is connected with a sealing water inlet of the front pump; the water inlet of a seal water unloading pipeline of the water feeding pump is connected with a seal water high-pressure outlet of the water feeding pump, and the water outlet of the seal water unloading pipeline of the water feeding pump is connected with a water inlet pipeline of the front pump; the water inlet of the water inlet pipeline of the cooler is connected with the water inlet pipeline of the water feed pump, and the water outlet of the water inlet pipeline of the cooler is connected with the hot side inlet of the cooler; the water inlet of the water outlet pipeline of the cooler is connected with the outlet of the hot side of the cooler, and the water outlet of the water outlet pipeline of the cooler is connected with the sealed water inlet main pipe.

Description

A structure of sealing water for boiler feed water pump after condensing unit is changed to back pressure unit

technical field

The invention relates to a boiler feed water pump sealing water structure after a condensing unit is changed to a back pressure unit, which is used in a thermal power station.

Background technique

The dissolved oxygen in the feed water of thermal power boilers is one of the important supervision indicators for thermal power generating units. The level of dissolved oxygen in the boiler feed water will directly affect the safe and economical operation of the unit.

During the operation of the boiler feed water pump, the feed water will transfer heat to the bearing through the pump shaft and the pump body, which will increase the temperature of the bearing and may cause the bearing to burn. Therefore, it is necessary to use the sealing water to cool the bearing. For the condensing unit, the condensate at the outlet of the condensate pump is generally used as the sealing water of the feed pump. After the condensate is deoxidized by vacuum in the condenser, the oxygen content is low. , a small amount of sealed water enters the boiler feed pump through the sealed water device of the boiler feed pump and mixes with a large amount of feed water, which basically does not increase the oxygen content of the feed water, so the oxygen content of the feed water deaerated by the deaerator meets the requirements of the "Thermal Power Generation Unit and Steam" Power Equipment Water Vapor Quality Standard.

For coal-fired power generating units that consume more than 300 grams of standard coal/kWh for power supply, encourage existing coal-fired generating units to replace heat supply, and promote the transformation of qualified condensing units into back pressure units. After the condensing unit is changed to a back pressure unit, the condenser is generally transformed into an open water tank or directly removed, and the unit system has no condensed water with low oxygen content. If softened water or demineralized water is used as sealing water, the above water The level of oxygen content is in milligrams. Even if the amount of sealed water is small, once the sealed water enters the boiler feed pump through the sealed water device of the boiler feed pump and mixes with the feed water, the oxygen content of the feed water will be significantly increased, which is seriously higher than that of the "thermal power generation unit and the According to the "Water Vapor Quality Standard for Steam Power Equipment", long-term use will inevitably accelerate the oxygen corrosion of the unit, causing the safety problem of the unit.

The Chinese invention patent with the patent number of ZL201820771337.6 discloses a boiler feed pump sealing water supply device and a boiler unit. The technical solution of the invention is to lead a water source from the high-pressure feed water at the outlet of the feed pump as the sealing water of the feed pump, which can avoid the need for feed water. The oxygen content is increased, and the safety of equipment operation is improved. However, due to the high pressure of the water source, in order to prevent damage to the feed pump due to excessive sealing water pressure, the technical solution of the invention is to set a pressure regulating valve to decompress the high-pressure water and then connect it to the feed pump sealing water device. Because the feed water pressure at the outlet of the feed pump is usually high, and the sealing water pressure requirement is low, the above technical solution has a very large pressure loss, and the feed water pressure head at the outlet of the feed pump is powered by a high-voltage motor. The above solution makes the feed pump run normally. , the outlet flow of the feed pump is larger than the rated working condition, the operation of the feed pump deviates from the rated working condition, the efficiency is reduced, and the high-voltage motor consumes a certain amount of power, which does not save energy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, and to provide a boiler feed pump sealing water structure after the condensing unit is changed to a back pressure unit with a reasonable structural design, which can ensure the oxygen content of the feed water at the outlet of the boiler feed pump. requirements to improve the safety and economy of equipment operation.

The technical scheme adopted by the present invention to solve the above problems is: a boiler feed water pump sealing water structure after a condensing unit is changed to a back pressure unit, including a deaerator, a feed pump, a water seal, a condenser, and a feed pump water inlet pipeline , Sealed water inlet main pipe, feed pump seal water inlet pipeline, feed pump seal water return pipeline and water seal return pipeline; the water outlet of the feed pump inlet pipeline is connected with the water inlet of the The water inlet of the water pipeline is connected with the sealing water inlet mother pipe, and the water outlet is connected with the sealing water inlet of the feed pump; the water inlet of the sealing water return line of the feed pump is connected with the low pressure outlet of the sealing water of the feed pump, and the water outlet is connected with the sealing water inlet of the water seal. The water inlet is connected; the water inlet of the water seal return line is connected with the water outlet of the water seal, and the water outlet is connected with the water inlet of the condenser; it is characterized in that: it also includes a front pump water inlet pipeline, a front pump, a cooler , Front pump sealing water inlet pipeline, feed pump sealing water unloading water pipeline, cooler water inlet pipeline and cooler water outlet pipeline; the water inlet of the front pump water inlet pipeline is connected with the water outlet of the deaerator, and the water outlet It is connected with the water inlet of the front pump; the water inlet of the feed pump water inlet pipeline is connected with the water outlet of the front pump; the water inlet of the sealing water inlet pipeline of the front pump is connected with the sealing water inlet mother pipe, and the water outlet is connected with the front pump. The sealing water inlet of the pump is connected; the water inlet of the sealing water unloading water pipeline of the feed pump is connected with the high pressure outlet of the sealing water of the feed pump, and the water outlet is connected with the water inlet pipeline of the front pump; the water inlet of the cooling water inlet pipeline is connected with the feed pump The water inlet pipeline is connected, the water outlet is connected with the hot side inlet of the cooler; the water inlet of the cooler water outlet pipeline is connected with the hot side outlet of the cooler, and the water outlet is connected with the sealing water inlet pipe.

A flow regulating valve is arranged on the sealing water inlet mother pipe of the present invention.

The invention also includes a cooling water inlet line and a cooling water return line, the cooling water inlet line is connected with the cold side inlet of the cooler, and the cooling water return line is connected with the cold side outlet of the cooler.

The cooler described in the present invention is a water-water cooler.

The condenser described in the present invention is equivalent to an open water tank, which is used as a water replenishing device for a back pressure unit.

The invention also includes isolation valve, water seal bypass pipeline and bypass isolation valve; isolation valves are installed on the water inlet and outlet of the water seal; the water inlet of the water seal bypass pipeline and the sealing water return of the feed pump The water line is connected, the water outlet is connected with the water seal return line, and the water seal bypass line is connected in parallel with the water seal; the bypass isolation valve is installed on the water seal bypass line.

The invention also includes a motor, which is connected with the pre-pump.

The invention also includes a coupler, and the motor is connected with the feed water pump through the coupler.

Compared with the prior art, the present invention has the following advantages and effects:

(1) A water source is drawn from the outlet of the front pump as the sealing water of the feed pump. The water source is the deoxygenated water after the deaerator deaerator. After the sealing water is mixed with the feed water, the oxygen content requirements of the feed water at the outlet of the feed pump can be guaranteed. It is beneficial to avoid oxygen corrosion of the unit and improve the operation safety of the unit.

(2) A water source is drawn from the outlet of the front pump as the sealing water of the feed pump. The pressure of the water at the outlet of the front pump is similar to the pressure of the original condensate water to seal the water. The original sealing water pipeline system can be used to reduce the amount of renovation works and save investment. .

(3) The front pump can increase the pressure at the inlet of the feed pump, meet the needs of the net suction head under different operating conditions of the feed pump, and effectively prevent the cavitation of the feed pump.

(4) The setting of the front pump, the total lifting head of the deaerated water at the outlet of the deaerator remains unchanged, the output power of the original motor is basically unchanged, and the operating conditions of the feed pump are basically the same as the original design conditions, which ensures that the motor and the feed The economy of pump operation.

Description of drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and through the examples. The following examples are to explain the present invention and the present invention is not limited to the following examples.

The embodiment of the present invention includes a deaerator 1, a pre-pump 2, a motor 3, a coupler 4, a feed pump 5, a water seal 6, a condenser 7, a cooler 8, a pre-pump water inlet line 101, and a feed pump inlet Water pipeline 102, sealing water inlet main pipe 103, front pump sealing water inlet pipeline 104, feed pump sealing water inlet pipeline 105, feed pump sealing water unloading water pipeline 106, feed pump sealing water return pipeline 107, water Seal back water line 108 , cooler water inlet line 109 , cooler water outlet line 110 , cooling water inlet line 301 and cooling water return line 302 .

The water inlet of the prepump water inlet pipeline 101 is connected to the water outlet of the deaerator 1 , and the water outlet is connected to the water inlet of the prepump 2 . The water inlet of the feed pump water inlet line 102 is connected to the water outlet of the prepump 2 , and the water outlet is connected to the water inlet of the feed pump 5 .

The water inlet of the sealing water inlet pipeline 104 of the prepump is connected to the sealing water inlet jelly 103 , and the water outlet is connected to the sealing water inlet of the prepump 2 . A flow regulating valve 11 is provided on the sealing water inlet main pipe 103 .

The water inlet of the sealing water inlet pipeline 105 of the feed water pump is connected to the sealing water inlet jelly 103 , and the water outlet is connected to the sealing water inlet of the feed pump 5 .

The water inlet of the sealing water unloading water pipeline 106 of the feed pump is connected to the high pressure outlet of the sealing water of the feed pump 5 , and the water outlet is connected to the water inlet pipeline 101 of the prepump. The water inlet of the sealing water return line 107 of the feed pump is connected to the low pressure outlet of the sealing water of the feed pump 5 , and the water outlet is connected to the water inlet of the water seal 6 .

The water inlet of the water seal return line 108 is connected to the water outlet of the water seal 6 , and the water outlet is connected to the water inlet of the condenser 7 .

The water inlet of the cooler water inlet line 109 is connected to the feed water pump water inlet line 102 , and the water outlet is connected to the hot side inlet of the cooler 8 . The water inlet of the cooler water outlet line 110 is connected to the hot side outlet of the cooler 8 , and the water outlet is connected to the sealing water inlet pipe 103 .

The cooling water inlet line 301 is connected to the cold side inlet of the cooler 8 , and the cooling water return line 302 is connected to the cold side outlet of the cooler 8 .

The cooler 8 is a water-water cooler. The cooler 8 is a double cooler at the same time, and the number of internal heat exchangers is two, one for use and one for standby. This configuration can ensure the inlet water temperature requirements of the sealing water of the feed water pump 5, and cool the bearings of the feed water pump 5 in time.

The condenser 7 is equivalent to an open water tank and communicates with the atmosphere. After the condensing unit is changed to the back pressure unit, the condenser 7 can be transformed into an open water tank connected to the atmosphere, as the water replenishment device of the back pressure unit.

An isolation valve 21 is installed on both the water inlet and the water outlet of the water seal 6 . One end of the water inlet of the water seal bypass line 401 is connected to the sealing water return line 107 of the feed pump, the water outlet is connected to the water seal return line 108 , and the water seal bypass line 401 is connected in parallel with the water seal 6 . The bypass isolation valve 23 is installed on the water seal bypass line 401 . After the water seal 6 in the original sealed water system is transformed into a back pressure unit, it is easy to have poor water return. Here, the isolation valve 21, the bypass isolation valve 23 and the water seal bypass line 401 are set at the original water seal, so that when the water return of the water seal 6 is not smooth, the sealing water of the feed pump 5 is connected to the condensate through the water seal bypass line 401. Steamer 7, to ensure the smooth return of the sealing water of the feed pump.

The motor 3 is connected to the prepump 2 through a coupling, and is connected to the feed pump 5 through a coupler 4 for driving the prepump 2 and the feed pump 5 .

A water source is drawn from the feed water inlet pipeline 102 at the outlet of the front pump 2 as the sealing water of the feed pump 5. The water source is the deoxygenated water after the deaerator 1 has deaerated. Since the temperature of the water source is relatively high, a cooler is installed. 8. The water source is cooled to the temperature required by the sealing water of the feed pump 5. After cooling, the sealing water of this road is mixed with the feed water, which can ensure the oxygen content requirement of the feed water at the outlet of the feed pump 5, which is beneficial to avoid oxygen corrosion of the unit and improve the operation safety of the unit. At the same time, since the pressure of the outlet water of the front pump 2 is similar to the pressure of the original sealing water from the condensed water, the sealing water pipeline system of the original condenser 7 and the feed pump 5 can be used for the old, reducing the amount of renovation works and saving investment. On the other hand, the prepump 2 can increase the pressure at the inlet of the feed pump 5, meet the requirements of the net suction head under different operating conditions of the feed pump 5, and effectively prevent the cavitation of the feed pump 5. At the same time, with the setting of the front pump 2, the total lifting head of the deaerated water at the outlet of the deaerator 1 remains unchanged, the output power of the original motor 3 is basically unchanged, and the operating conditions of the feed pump 5 are basically the same as the original design conditions, ensuring that Economical operation of the motor 3 and the feed pump 5.

In addition, it should be noted that the specific embodiments described in this specification may have different shapes and names of parts and components, and the above content described in this specification is only an illustration of the structure of the present invention. All equivalent changes or simple changes made according to the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention.

Claims (8)

1. A boiler feed water pump sealing water structure after a condensing unit is changed to a back pressure unit, including a deaerator, a feed pump, a water seal, a condenser, a feed pump water inlet pipeline, a sealing water inlet water mother pipe, and a feed pump seal The water inlet pipeline, the sealing water return pipeline of the feed pump and the water sealing return pipeline; the water outlet of the water inlet pipeline of the feed pump is connected with the water inlet of the feed pump; the water inlet of the sealing water inlet pipeline of the feed pump is connected with the sealing water inlet jellyfish The water outlet is connected with the sealing water inlet of the feed pump; the water inlet of the sealing water return line of the feed pump is connected with the low pressure outlet of the sealing water of the feed pump, and the water outlet is connected with the water inlet of the water seal; The water inlet is connected with the water outlet of the water seal, and the water outlet is connected with the water inlet of the condenser; it is characterized in that: it also includes a front pump water inlet pipeline, a front pump, a cooler, a front pump sealing water inlet pipeline, The sealing water unloading water pipeline of the feed pump, the water inlet pipeline of the cooler and the water outlet pipeline of the cooler; the water inlet of the water inlet pipeline of the front pump is connected with the water outlet of the deaerator, and the water outlet is connected with the water inlet of the front pump; The water inlet of the water pump inlet line is connected with the water outlet of the front pump; the water inlet of the sealing water inlet line of the front pump is connected with the sealing water inlet mother pipe, and the water outlet is connected with the sealing water inlet of the front pump; the sealing water of the feed pump is sealed The water inlet of the water unloading water line is connected with the high pressure outlet of the sealing water of the feed pump, and the water outlet is connected with the water inlet line of the pre-pump; The hot side inlet of the cooler is connected; the water inlet of the water outlet pipeline of the cooler is connected with the hot side outlet of the cooler, and the water outlet is connected with the sealing water inlet pipe. 2 . The sealing water structure of the boiler feed water pump after the condensing unit is changed to the back pressure unit according to claim 1 , wherein a flow regulating valve is provided on the water inlet main pipe of the sealing water. 3 . 3. the boiler feed water pump sealing water structure after the condensing unit is changed to the back pressure unit according to claim 1, it is characterized in that: also comprise cooling water inlet line and cooling water return line, cooling water inlet line and cooling water The cold side inlet of the cooler is connected, and the cooling water return line is connected to the cold side outlet of the cooler. 4 . The sealing water structure of the boiler feed water pump after the condensing unit is changed to the back pressure unit according to claim 1 , wherein the cooler is a water-water cooler. 5 . 5. The sealing water structure of the boiler feed water pump after the condensing unit is changed to the back pressure unit according to claim 1, it is characterized in that: the described condenser is equivalent to an open water tank, as the water replenishment of the back pressure unit device. 6. The sealing water structure of the boiler feed pump after the condensing unit is changed to the back pressure unit according to claim 1, is characterized in that: it also comprises isolation valve, water seal bypass pipeline and bypass isolation valve; the water seal There are isolation valves installed on the water inlet and outlet of the water seal; the water inlet of the water seal bypass line is connected to the seal water return line of the feed pump, the water outlet is connected to the water seal return line, and the water seal bypass line is connected to the water seal Parallel; bypass isolation valve installed on the water seal bypass line. 7 . The sealing water structure of the boiler feed water pump after the condensing unit is changed to the back pressure unit according to claim 1 , further comprising a motor, which is connected to the front pump. 8 . 8 . The sealing water structure of the boiler feed water pump after the condensing unit is changed to the back pressure unit according to claim 1 , further comprising a coupler, and the motor is connected to the feed water pump through the coupler. 9 .

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