CN-122015071-A - Corrosion prevention device and method for low-temperature economizer

CN122015071ACN 122015071 ACN122015071 ACN 122015071ACN-122015071-A

Abstract

The invention provides an anti-corrosion device and method for a low-temperature economizer, and belongs to the technical field of thermal power generation. The device comprises a low-temperature economizer, a flue gas temperature sensor and a flue gas component analyzer which are sequentially arranged from the upstream to the downstream of a flue, wherein the low-temperature economizer comprises a high-temperature section heat exchanger and a low-temperature Duan Huanre device, a condensation water communication branch pipe and a heat exchanger bypass pipe which are connected in parallel are communicated with each other by a high-temperature section waste heat jellyfish pipe, the condensation water communication branch pipe is respectively connected with a plurality of low-pressure heaters, a high-temperature section electric regulating valve is arranged on the heat exchanger bypass pipe, a plurality of heaters are connected in parallel by the low-temperature section waste heat jellyfish pipe, and a low-temperature Duan Diandong regulating valve is arranged on a low-temperature Duan Yu hot water main pipe. The high temperature section is through setting up a plurality of lateral conduit, and flexible regulation height Wen Duanyu hot water main pipe and condensed water pipeline's hookup location ensures that the condensed water heating process possesses higher waste heat recovery efficiency. The low-temperature section independently builds a circulation network, so that the influence of the low-temperature section of the low-temperature economizer on the heat recovery system of the steam turbine is reduced.

Inventors

JIANG PEIPENG
LI YUAN
LIU XIAOMIN
ZHOU PENG
CHEN SONGSONG
CHENG BAOGUO
WANG DAHAI
HUANG ZHIYUAN
LIU GUANGYAO
WU XINGHUA

Assignees

山东华电节能技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260106

Claims (10)

1. The corrosion prevention device of the low-temperature economizer is characterized by comprising the low-temperature economizer, a flue gas temperature sensor and a flue gas component analyzer which are sequentially arranged from the upstream to the downstream of a flue, wherein the low-temperature economizer comprises a high-temperature section heat exchanger and a low-temperature Duan Huanre device, the high-temperature section heat exchanger is communicated with a high-temperature section waste heat jellyfish pipe, the high-temperature section waste heat jellyfish pipe is communicated with a condensate water connection branch pipe and a heat exchanger bypass pipeline which are connected in parallel, the condensate water connection branch pipe is respectively connected with a plurality of low-pressure heaters, a high-temperature circulating water pump is arranged on the high-temperature section waste heat jellyfish pipe, and a high-temperature section electric regulating valve is arranged on the heat exchanger bypass pipeline; The low-temperature Duan Huanre device is communicated with a low-temperature Duan Yu hot water main pipe, the low-temperature section waste heat jellyfish pipe is communicated with a plurality of heater pipelines which are connected in parallel, the heater pipelines are communicated with a heater, and a low-temperature Duan Diandong regulating valve is arranged on the low-temperature Duan Yu hot water main pipe.
2. The corrosion protection device for the low-temperature economizer according to claim 1, wherein a temperature sensor is arranged at an outlet of the low-pressure heater, electric gate valves are respectively arranged on a plurality of the branch pipes, and check valves are arranged between adjacent branch pipes on the condensate water communication branch pipe.
3. The corrosion protection device for a low-temperature economizer according to claim 1, wherein a pressure regulating valve is provided downstream of a branch pipe on the condensate communication branch pipe.
4. The corrosion protection device for the low-temperature economizer according to claim 1, wherein a circulating water pump is arranged on a high Wen Duanyu hot water main pipe, and temperature sensors are respectively arranged at an inlet end and an outlet end of the high-temperature section heat exchanger.
5. The corrosion protection device for the low-temperature economizer according to claim 1, wherein an emergency heater is arranged at the upstream of the heater pipeline, and a heat source of the emergency heater is auxiliary steam for a plant.
6. The corrosion protection device for a low-temperature economizer according to claim 1, wherein the heater comprises a primary air heater arranged on a primary air duct and a secondary air heater arranged on a secondary air duct, and temperature sensors are respectively arranged on the primary air duct and the secondary air duct at the upstream of the heaters.
7. The corrosion protection device for the low-temperature economizer according to claim 1, wherein a circulating water pump is arranged on the low-temperature Duan Yu hot water main pipe, and a temperature sensor is arranged at the circulating water inlet end of the low-temperature Duan Huanre device.
8. A method for corrosion protection of a low-temperature economizer based on a corrosion protection device for a low-temperature economizer according to any one of claims 1-7, characterized by comprising the following steps: S1, comparing the outlet condensate water temperature of a plurality of low-pressure heaters with the inlet and outlet temperatures of a high-temperature section heat exchanger, supplying water to a high-temperature section waste heat jellyfish tube through a low-pressure heater with the condensate water outlet temperature lower than the inlet temperature of the high-temperature section heat exchanger and the temperature difference smallest, heating through the high-temperature section heat exchanger, and returning water to the downstream of the low-pressure heater with the water outlet temperature lower than the outlet temperature of the high-temperature section heat exchanger and the temperature difference smallest; s2, supplying water to the air heater through a low-temperature Duan Yu hot water main pipe, and adjusting a low-temperature Duan Diandong adjusting valve to enable the temperature of the low-temperature section waste heat water to be higher than a set value; s3, calculating the dew point temperature of the flue gas through the flue gas components detected by the flue gas component analyzer; S4, adjusting the high-temperature section electric regulating valve to enable the temperature measured by the flue gas temperature sensor to be in a set temperature range above the dew point temperature of the flue gas.
9. The corrosion prevention method for a low-temperature economizer of a corrosion prevention apparatus for a low-temperature economizer according to claim 8, wherein the condensed water in the condensed water pipe is utilized to supplement water into the high-temperature section residual water main pipe and fix pressure through the branch pipe, the high-temperature section residual water circulation is established, then the inlet and outlet temperatures of the high-temperature Duan Huanre device are detected, and the opening and closing states of the electric gate valve of the branch pipe are adjusted.
10. The corrosion prevention method for a low-temperature economizer of the corrosion prevention device for a low-temperature economizer according to claim 8, wherein in the step S2, circulating water in a low-temperature Duan Yu hot water main pipe is heated by an emergency heater, and the opening degree of a low-temperature Duan Diandong regulating valve is adjusted based on the air inlet temperature of a primary air duct and a secondary air duct and the temperature of low-temperature section waste heat water; Or in S4, when the temperature measured by the flue gas temperature sensor is lower than the set temperature range, opening the high-temperature-section electric regulating valve, and when the temperature measured by the flue gas temperature sensor is higher than the set temperature range, closing the opening of the high-temperature-section electric regulating valve.

Description

Corrosion prevention device and method for low-temperature economizer Technical Field The invention belongs to the technical field of thermal power generation, and particularly relates to an anti-corrosion device and method for a low-temperature economizer. Background The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. In the thermal power generation process, the waste heat loss of the discharged smoke of the coal-fired unit boiler is main energy loss, and can account for about 4% of the heat released by the fuel, and the coal consumption can be effectively reduced by recycling the waste heat of discharged smoke. The low-temperature economizer is additionally arranged in the area between the air preheater and the desulfurizing tower of the flue gas and wind system, the waste heat of the flue gas is recovered by the low-temperature economizer, and the condensation water of the heat recovery system is heated by the waste heat, so that the method is an effective means for recovering the waste heat. However, in actual operation, it was found that the low-temperature economizer is prone to corrosion, and in particular, the corrosion of the rear section of the low-temperature economizer is particularly serious. The method is characterized in that when the coal type changes or the load of a unit is low, the actual operation working condition deviates from the design working condition of the low-temperature economizer, so that the partial region of the low-temperature economizer has a temperature lower than the acid dew point of flue gas, and the acid dew is condensed on the pipe wall of the region, thereby causing corrosion of the heat transfer pipe. And the current low-temperature economizer takes the waste heat water temperature as a control target, so that the flue gas temperature is difficult to effectively adjust. The low-temperature economizer which is idle due to corrosion problem cannot recover the waste heat of the flue gas, and the resistance of a flue gas and wind system can be increased. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide an anti-corrosion device and method for a low-temperature economizer, which are used for controlling the temperature of low-temperature section flue gas of the low-temperature economizer to be not lower than the acid dew point temperature by adjusting the operation parameters of a system, preventing the corrosion of the low-temperature economizer and prolonging the service life. In order to achieve the above purpose, the technical scheme of the invention is as follows: The corrosion prevention device of the low-temperature economizer comprises a low-temperature economizer, a flue gas temperature sensor and a flue gas component analyzer which are sequentially arranged from the upstream to the downstream of a flue, wherein the low-temperature economizer comprises a high-temperature section heat exchanger and a low-temperature Duan Huanre device, the high-temperature section heat exchanger is communicated with a high-temperature section waste heat jellyfish pipe, the high-temperature section waste heat jellyfish pipe is communicated with a condensation water communication branch pipe and a heat exchanger bypass pipe which are connected in parallel, the condensation water communication branch pipe is respectively connected with a plurality of low-pressure heaters, a high-temperature circulating water pump is arranged on the high-temperature section waste heat jellyfish pipe, and a high-temperature section electric regulating valve is arranged on the heat exchanger bypass pipe; The low-temperature Duan Huanre device is communicated with a low-temperature Duan Yu hot water main pipe, the low-temperature section waste heat jellyfish pipe is communicated with a plurality of heater pipelines which are connected in parallel, the heater pipelines are communicated with a heater, and a low-temperature Duan Diandong regulating valve is arranged on the low-temperature Duan Yu hot water main pipe. In a second aspect, the corrosion prevention method for the low-temperature economizer based on the corrosion prevention device for the low-temperature economizer comprises the following steps: S1, comparing the outlet condensate water temperature of a plurality of low-pressure heaters with the inlet and outlet temperatures of a high-temperature section heat exchanger, supplying water to a high-temperature section waste heat jellyfish tube through a low-pressure heater with the condensate water outlet temperature lower than the inlet temperature of the high-temperature section heat exchanger and the temperature difference smallest, heating through the high-temperature section heat exchanger, and re