阅读说明：本技术 一种变频余热发电机组 (Frequency conversion waste heat generating set ) 是由 查晓冬 魏辉 甘国稳 于 2020-07-29 设计创作，主要内容包括：本发明公开了一种变频余热发电机组,其包括蒸发器、膨胀机、发电机、冷凝器和冷媒泵,蒸发器的冷媒侧、膨胀机、冷凝器的冷媒侧和冷媒泵闭环连接,膨胀机的转子与发电机的转子连接,发电机为变频发电机。由于本发明采用变频发电机,发电频率与机组的转速无关,且连续可调,因此发电频率能够与市电频率保持一致,当负荷变化时,无需与市电解列,避免出现解列期间发电机内部发热而导致的机组损坏。(The invention discloses a variable-frequency waste heat generator set which comprises an evaporator, an expander, a generator, a condenser and a refrigerant pump, wherein the refrigerant side of the evaporator, the refrigerant side of the expander and the refrigerant side of the condenser are in closed-loop connection with the refrigerant pump, a rotor of the expander is connected with a rotor of the generator, and the generator is a variable-frequency generator. Because the variable-frequency generator is adopted, the generating frequency is irrelevant to the rotating speed of the generator set and is continuously adjustable, so that the generating frequency can be kept consistent with the commercial power frequency, and when the load changes, the generator set does not need to be disconnected with the commercial power, thereby avoiding the generator set damage caused by the internal heating of the generator during the disconnection.)

1. The variable-frequency waste heat generator set is characterized by comprising an evaporator, an expander, a generator, a condenser and a refrigerant pump, wherein the refrigerant side of the evaporator, the refrigerant side of the expander and the refrigerant side of the condenser are in closed-loop connection with the refrigerant pump, a turbine shaft of the expander is connected with a rotor of the generator, and the generator is a variable-frequency generator.

2. The variable frequency waste heat generator set of claim 1, wherein the generator comprises a frequency converter comprising a rectifier and an inverter.

3. The variable-frequency waste heat generator set according to claim 1, further comprising a gas-liquid separator, wherein the gas-liquid separator is arranged on a refrigerant outlet side of the evaporator, a liquid outlet of the gas-liquid separator is connected with a bypass pipe, and the other end of the bypass pipe is connected to the upstream of the condenser.

4. The variable-frequency waste heat generator set according to claim 3, wherein a first electric valve is arranged between the exhaust port of the gas-liquid separator and the air inlet of the expansion machine.

5. The variable-frequency waste heat generator set according to claim 3, wherein a second electric valve is arranged on the bypass pipe.

6. The variable-frequency waste heat generator set according to claim 1, further comprising a liquid storage tank, wherein a refrigerant inlet of the liquid storage tank is connected with a refrigerant side outlet of the condenser, and a refrigerant outlet of the liquid storage tank is connected with a refrigerant inlet of the refrigerant pump.

7. The variable-frequency waste heat generator set according to claim 1, further comprising a cooling tower and a circulating water pump, wherein a cooling water outlet of the condenser is connected to an inlet of the circulating water pump, an outlet of the circulating water pump is connected to an inlet of the cooling tower, and an outlet of the cooling tower is connected to a cooling water inlet of the condenser.

8. The variable-frequency waste heat generator set according to claim 5, wherein a refrigerant tank is connected to the bypass pipe upstream of the second electric valve, a liquid level switch is arranged in the refrigerant tank, the liquid level switch defines an upper liquid level limit and a lower liquid level limit, the lower liquid level limit is higher than a liquid discharge port of the refrigerant tank, the electric valve is set to be closed when an actual refrigerant liquid level in the refrigerant tank drops to the lower liquid level limit, and the electric valve is opened when the actual refrigerant liquid level in the refrigerant tank reaches the upper liquid level limit.

Technical Field

The invention relates to the field of waste heat power generation, in particular to a variable-frequency waste heat generator set.

Background

The traditional waste heat generator set is connected to the grid in a gear or direct-drive mode, so that the power generation frequency of the generator set is kept consistent with the commercial power, and the rotating speed of the generator set is directly related to the power generation frequency. When the load changes, the frequency is asynchronous with the commercial power after the frequency is higher than or lower than the rated rotating speed within a certain range, the frequency needs to be disconnected with the commercial power, the electricity generated by the generator is not used on the internet during disconnection, the electricity can become the heat inside the generator, and the unit is easy to damage.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a variable-frequency waste heat generator set which comprises an evaporator, an expander, a generator, a condenser and a refrigerant pump, wherein the refrigerant side of the evaporator, the refrigerant side of the expander and the refrigerant side of the condenser are connected with the refrigerant pump in a closed loop mode, a turbine shaft of the expander is connected with a rotor of the generator, and the generator is a variable-frequency generator.

The invention has the beneficial effects that: because the generator adopted by the embodiment is a variable frequency generator, the output frequency of the generator is irrelevant to the rotating speed of the unit and is continuously adjustable, so that the generating frequency can be kept consistent with the commercial power frequency, even if the rotating speed of the turbine of the expansion machine is changed due to load change, the output frequency of the generator can be kept unchanged, the generator is not required to be disconnected with the commercial power, and the unit damage caused by the internal heating of the generator during the disconnection is avoided.

In certain embodiments, the generator comprises a frequency converter comprising a rectifier and an inverter. The frequency converter is built in the frequency conversion generator. The rectifier is used to convert the initial electricity generated by the generator into direct current. The inverter is used to convert the direct current into alternating current of a desired frequency.

In some embodiments, the evaporator further comprises a gas-liquid separator, the gas-liquid separator is arranged on the refrigerant outlet side of the evaporator, the liquid outlet of the gas-liquid separator is connected with the bypass pipe, and the other end of the bypass pipe is connected to the upstream of the condenser. The gas-liquid separator can separate refrigerant liquid drops in the refrigerant gas, and the refrigerant liquid drops enter the condenser from the bypass pipe, so that the refrigerant liquid drops are prevented from damaging the expansion machine.

In some embodiments, a first electrically operated valve is provided between the exhaust port of the gas-liquid separator and the inlet port of the expander. The first electric valve is used for controlling the refrigerant gas to enter the expander.

In some embodiments, a second electrically operated valve is provided on the bypass line. The second electric valve is used for controlling the refrigerant liquid drops separated from the gas-liquid separator to enter the condenser.

In some embodiments, the refrigerant pump further comprises a liquid storage tank, a refrigerant inlet of the liquid storage tank is connected with the refrigerant outlet of the condenser, and a refrigerant outlet of the liquid storage tank is connected with the refrigerant inlet of the refrigerant pump. The liquid storage tank can be used for storing refrigerant liquid and sometimes can be used for adjusting the refrigerant flow.

In some embodiments, the cooling tower and the circulating water pump are further included, the cooling water outlet of the condenser is connected with the inlet of the circulating water pump, the outlet of the circulating water pump is connected with the inlet of the cooling tower, and the outlet of the cooling tower is connected with the cooling water inlet of the condenser. In the condenser, the cooling water cools the refrigerant gas in the condenser to form a liquid refrigerant. After flowing out of the condenser, the cooling water is pumped to a cooling tower by a circulating water pump for cooling and then flows back to the condenser.

In some embodiments, a refrigerant tank is connected to the bypass pipe at an upstream of the second electric valve, a liquid level switch is arranged in the refrigerant tank, the liquid level switch defines an upper liquid level limit and a lower liquid level limit, the lower liquid level limit is higher than a liquid discharge port of the refrigerant tank, the electric valve is set to be closed when an actual refrigerant liquid level in the refrigerant tank drops to the lower liquid level limit, and the electric valve is opened when the actual refrigerant liquid level in the refrigerant tank reaches the upper liquid level limit. Because load changes and fluctuates, the separated refrigerant liquid drop also can fluctuate, if the bypass pipe is not controlled, when the load changes and fluctuates, refrigerant gas can enter a low-pressure side through the bypass pipe, and therefore system efficiency and stability are affected.

Drawings

Fig. 1 is a schematic diagram of a variable-frequency waste heat generator set according to an embodiment of the invention.

Fig. 2 is a schematic diagram of a variable-frequency waste heat generator set according to another embodiment of the invention.

Fig. 3 is a schematic diagram of a variable-frequency waste heat generator set according to another embodiment of the invention.

Description of the symbols:

evaporator 1

Expander 2

Generator 3

Condenser 4

Refrigerant pump 5

Frequency converter 6

Rectifier 7

Inverter 8

Cooling tower 9

Circulating water pump 10

Liquid storage tank 11

Gas-liquid separator 12

Bypass pipe 13

First electrically operated valve 14

Second electrically operated valve 15

Refrigerant tank 16

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

According to one aspect of the invention, the invention provides a variable frequency waste heat generator set. Referring to fig. 1-3, in various embodiments of the present disclosure, the variable frequency waste heat generator set includes an evaporator 1, an expander 2, a generator 3, a condenser 4, and a refrigerant pump 5, a refrigerant side of the evaporator 1, a refrigerant side of the expander 2, and a refrigerant side of the condenser 4 are connected to the refrigerant pump 5 in a closed loop, a turbine shaft of the expander 2 is connected to a rotor of the generator 3, wherein the generator 3 is a variable frequency generator.

The generator 3 comprises a frequency converter 6, the frequency converter 6 is built in the generator 3, the frequency converter 6 comprises a rectifier 7, and the rectifier 7 is connected with an inverter 8. The rectifier 7 serves to convert the initial electricity generated by the generator 3 into direct current. The inverter 8 is used to convert the direct current into alternating current of a desired frequency.

Because the variable-frequency generator is adopted in the embodiment, the generating frequency is irrelevant to the rotating speed of the generator set and is continuously adjustable, so that the generating frequency can be kept consistent with the commercial power frequency, and when the load changes, the generator set does not need to be disconnected with the commercial power, and the generator set damage caused by internal heating of the generator 3 during disconnection is avoided.

Further, referring to fig. 2, the variable frequency waste heat power generator unit further includes a cooling tower 9 and a circulating water pump 10, a cooling water outlet of the condenser 4 is connected to an inlet of the circulating water pump 10, an outlet of the circulating water pump 10 is connected to an inlet of the cooling tower 9, and an outlet of the cooling tower 9 is connected to a cooling water inlet of the condenser 4. In the condenser 4, the cooling water cools the refrigerant gas in the condenser 4 to form a liquid refrigerant. After flowing out of the condenser 4, the cooling water is pumped to the cooling tower 9 by the circulating water pump 10 to be cooled, and then flows back to the condenser 4.

Further, with reference to fig. 2, the variable frequency waste heat generator set further includes a liquid storage tank 11, a refrigerant inlet of the liquid storage tank 11 is connected to the refrigerant outlet of the condenser 4, and a refrigerant outlet of the liquid storage tank 11 is connected to a refrigerant inlet of the refrigerant pump 5.

In order to prolong the service life of the expander 2 of the variable frequency waste heat generating set of the present invention, please refer to fig. 3, in some embodiments, the variable frequency waste heat generating set further includes a gas-liquid separator 12, the gas-liquid separator 12 is disposed at the refrigerant outlet side of the evaporator 1, a liquid outlet of the gas-liquid separator 12 is connected to a bypass pipe 13, and the other end of the bypass pipe 13 is connected to the upstream of the condenser 4. The gas-liquid separator 12 can separate refrigerant droplets from the refrigerant gas, and the refrigerant droplets enter the condenser 4 through the bypass pipe 13, so that the refrigerant droplets are prevented from damaging the expander 2. Further, a first motor-operated valve 14 is provided between the exhaust port of the gas-liquid separator 12 and the intake port of the expander 2. The first electric valve 14 is used for controlling the refrigerant gas to enter the expander 2. In some embodiments, a second electrically operated valve 15 is provided on the bypass pipe 13. The second electric valve 15 controls the opening and closing of the bypass pipe 13.

In the embodiment shown in fig. 3, the separated refrigerant liquid droplets fluctuate due to load variation and fluctuation, and if the bypass pipe 13 is not controlled, refrigerant gas enters the low-pressure side through the bypass pipe 13 when the load variation fluctuates, thereby affecting the system efficiency and stability. In order to solve the technical problem, in some embodiments, a refrigerant tank 16 is connected to the bypass pipe 13 at the upstream of the second electric valve 15, a liquid level switch is arranged in the refrigerant tank 16, the liquid level switch defines an upper liquid level limit and a lower liquid level limit, the lower liquid level limit is higher than a liquid discharge port of the refrigerant tank 16, the electric valve is set to be closed when an actual refrigerant liquid level in the refrigerant tank 16 is reduced to the lower liquid level limit, and the second electric valve 15 is opened when the actual refrigerant liquid level in the refrigerant tank 16 reaches the upper liquid level limit. In the embodiment, the refrigerant tank 16 is connected to the bypass pipe 13, and the opening and closing of the second electric valve 15 are controlled according to the liquid level, so that the lower limit of the liquid level is higher than the liquid discharge port of the refrigerant tank 16, liquid refrigerant always exists in the refrigerant tank 16, and refrigerant gas is prevented from entering the low-pressure side.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.