Raw water heating system for thermal power plant and control method for raw water heating system

Abstract

The invention relates to the technical field of power plant desalted water preparation systems and waste heat utilization, and discloses a raw water heating system for a thermal power plant. The raw water heating system comprises a raw water pipeline and a heat supply network circulating water return pipeline, and further comprises a raw water heater, the cold side and the hot side of the raw water heater are connected to the raw water pipeline and the heat supply network circulating water return pipeline correspondingly through pipelines, a heat supply network water booster pump is arranged on a fourth pipeline, a circulating water flow rate regulating valve group is arranged on a third pipeline, a first temperature measuring point is arranged at the position, located at the upstream of apipeline raw water outlet, of the raw water pipeline, and a second temperature measuring point is arranged at the position, located at the downstream of a pipeline raw water inlet, of the raw water pipeline. The invention further discloses a control method for the raw water heating system for the thermal power plant. According to the raw water heating system for the thermal power plant and the control method for the raw water heating system, low-grade heat supply network circulating water return water is used for heating raw water, on the premise that the outlet water temperature of the raw water is guaranteed, gradient utilization of energy is realized, conventional use of high-grade steam for heating is avoided, the thermal economical performance of a unit can be improved, and the raw water heating system is environmentally-friendly and energy- saving.

Description

technical field [0001] The invention relates to the technical field of a power plant desalinated water preparation system and waste heat utilization, in particular to a thermal power plant raw water heating system and a control method thereof. Background technique [0002] The operation of a thermal power plant is usually accompanied by a certain loss of steam and water, especially for some units with a large heating load, the water replenishment capacity of the system is as high as several hundred tons per hour, and the thermal power plant is usually equipped with a desalinated water preparation that matches the water replenishment capacity. Raw water from workshops and power plants undergoes multi-step treatment procedures to produce qualified desalinated water. Nowadays, with the decline of raw water quality and the increase of water replenishment, most desalinated water preparation systems of power plants use membrane method for ion removal, but the membrane method treat...

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Problems solved by technology

[0004] However, in the traditional raw water heating system, since the heating medium is steam, the pipes and valves on the high temperature side of the system need to be of higher grades, and additional insulation is required. Some valves may need to use imported equipment, and general raw water heating The steam pipeline is used to lead from the turbine room to the desalinated water preparation workshop. The path is long, which virtually increases the investment in the pipe rack in the factory area.

In addition, the steam pipeline also poses a certain safety hazard to the operators of the desalinated water preparation workshop

[0005] Moreover, in terms of the principle of cascade utilization of energy, it is uneconomical to use auxiliary steam to heat raw water. The heat transfer temperature difference is as high as 250°C or more. irreversible loss of

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