System and method for recovery and use of waste heat

Claims

1. A waste heat recovery and utilization system used in the aluminum electrolysis process and comprising: a subsystem for removing waste heat from the material, a subsystem for recovering waste gas heat, and a control subsystem; the material waste heat removal subsystem is connected to the waste gas heat recovery subsystem for the purpose of removing heat to be recovered from the material by means of waste gas flowing through the material waste heat removal subsystem; the waste gas heat recovery subsystem is used to recover and utilize the heat of the waste gas removed from the electrolytic cell for aluminum electrolysis and the waste heat removed from the material from which the waste heat is to be recovered; and The control subsystem is used to regulate and monitor the operating parameters of the waste heat removal subsystem and the waste gas heat recovery subsystem during the waste heat recovery and utilization process.

2. The system of claim 1, wherein the subsystem for removing waste heat from the material is further used to heat the material heated by the waste gas passing through the subsystem for removing waste heat from the material.

3. The system according to claim 1, in which the subsystem for removing waste heat from the material comprises: a pipe for introducing waste gas, a pipe for removing waste gas and a device for removing waste heat from the material; the inlet of the pipe for introducing the exhaust gas communicates with the exhaust gas heat recovery subsystem, and the outlet of the pipe for introducing the exhaust gas communicates with the device for removing the exhaust heat from the material; the inlet of the exhaust gas pipe communicates with the device for removing waste heat from the material, and the outlet of the exhaust gas pipe communicates with the exhaust gas heat recovery subsystem; and A device for removing waste heat from a material is used to place the material from which the waste heat is to be recovered.

4. The system according to paragraph 3, in which the subsystem for removing heat waste from the material additionally comprises: the first mesh filter located at the inlet or outlet of the exhaust gas inlet pipe; the second mesh filter located at the inlet of the exhaust gas pipe; a first control valve located on the exhaust gas inlet pipe and designed to regulate the flow rate of exhaust gas entering the device for removing waste heat from the material; a second control valve located on the exhaust gas discharge pipe and designed to regulate the flow rate of exhaust gas leaving the device for removing waste heat from the material; a first temperature sensor located on the exhaust gas discharge pipe and designed to measure the temperature of the exhaust gas leaving the device for removing waste heat from the material; and a first flow meter located on the exhaust gas discharge pipe and designed to measure the flow rate of exhaust gas leaving the device for removing waste heat from the material.

5. The system according to paragraph 3, in which the device for removing the heat leaving the material is a sealed structure and contains: a carrier tray located in the device for removing waste heat from the material and intended for transporting the material from which the waste heat is subject to recovery; a telescopic mechanism located under the supporting tray and designed to move the material, the waste heat from which is to be recovered, into or out of the device for removing the waste heat from the material; a material tray located above the carrier tray and intended for placing the material from which the heat is to be recovered; a projection located on the material tray and designed to insulate the lower surface of the material, from which the heat is to be recovered, from the upper surface of the material tray; and a protective device located in a device for removing waste heat from a material and designed to protect the material from which the waste heat is to be recovered.

6. The system of claim 1, wherein the waste gas heat recovery subsystem comprises a waste heat processing unit, a waste gas supply pipe, a second flow meter, a second temperature sensor, and a third control valve; The exhaust gas supply pipe is used to supply exhaust gas discharged from the aluminum electrolysis cell to the waste heat treatment unit; the waste heat processing unit is used to convert the heat of the exhaust gas discharged from the electrolytic cell for aluminum electrolysis and the waste heat recovered from the material from which the waste heat is to be recovered into usable heat; the second flow meter is located near the outlet of the exhaust gas supply pipe and is designed to measure the flow rate of exhaust gas in the exhaust gas supply pipe; a second temperature sensor located on the exhaust gas supply pipe and designed to measure the temperature of the exhaust gas in the exhaust gas supply pipe; and a third control valve installed on the exhaust gas supply pipe and designed to regulate the flow rate of exhaust gas passing through the exhaust gas supply pipe.

7. The system of claim 6, wherein the waste heat processing unit comprises: an exhaust gas heat exchanger connected to the exhaust gas supply pipe outlet and designed to convert the recovered exhaust heat into hot water or steam; a cleaning unit connected to the exhaust gas heat exchanger and designed to treat harmful substances coming from the exhaust gas heat exchanger; an intermediate heat exchanger connected to the exhaust gas heat exchanger through the first circulation circuit and communicating with the heat consumer through the second circulation circuit, for regulating, controlling and distributing the heat coming from the exhaust gas heat exchanger; and a water tank located in the second circulation circuit to stabilize the heat supplied to the consumer.

8. A method for recovery and use of waste heat, carried out in a control subsystem of a waste heat recovery and use system according to any of paragraphs 1-7, comprising the following steps: obtaining an initial flow rate of exhaust gas in the exhaust gas heat recovery subsystem and a heat exchange rate for the material from which the waste heat is to be recovered when it is detected that the material from which the waste heat is to be recovered is placed in the material waste heat removal subsystem, wherein the heat exchange rate corresponds to the amount of heat removed per unit time from the exhaust gas passing through the material waste heat removal subsystem; determining a specified flow rate of exhaust gas passing through the material waste heat removal subsystem based on the heat exchange rate, wherein the heat exchange rate is positively correlated with the specified flow rate; and regulation and control of the opening degree of various control valves in the waste heat recovery and utilization system in accordance with the initial flow rate and the set flow rate.

9. The method according to paragraph 8, in which the determination of the heat exchange rate for the material from which the heat is to be recovered comprises the following steps: determination of the initial temperature of the exhaust gas in the exhaust gas heat recovery subsystem, the initial residual heat of the material from which the heat is to be recovered, and the specified duration of heat removal from the material from which the heat is to be recovered; determining the residual heat of the material from which the waste heat is to be recovered, at a temperature corresponding to the initial temperature, as the specified residual heat; and Determining the heat transfer rate based on the initial residual heat, the specified residual heat, and the specified duration.

10. The method according to paragraph 9, further comprising the following steps: real-time monitoring of the temperature of the exhaust gas leaving the material waste heat removal subsystem during the process of removing heat from the material from which the waste heat is to be recovered; and stopping the removal of heat from the material from which the waste heat is to be recovered if it is detected that the temperature of the waste gas is less than or equal to the initial temperature.