Cascade energy utilization heat supply system under low-load working condition and control method thereof

Abstract

The invention relates to a cascade energy utilization heat supply system under a low-load working condition and a control method thereof. The cascade energy utilization heat supply system comprises aboiler, a turbine high-pressure cylinder, a turbine medium-pressure cylinder, a turbine low-pressure cylinder, a first ejector, a second ejector, a first heat supply network heater and a second heat supply network heater. The boiler, the turbine high-pressure cylinder, the turbine medium-pressure cylinder and the turbine low-pressure cylinder sequentially communicate through pipelines. A steam outlet of the turbine medium-pressure cylinder separately communicates with a power steam inlet of the first ejector, a power steam inlet of the second ejector and the first heat supply network heater through pipelines. A steam outlet of the turbine low-pressure cylinder communicates with a low-pressure steam inlet of the first ejector through a pipeline. An outlet of the first ejector separately communicates with a low-pressure steam inlet of the second ejector and an outlet of the second ejector through pipelines. The outlet of the first ejector and the outlet of the second ejector further communicate with the second heat supply network heater through pipelines. The first heat supply network heater communicates with the second heat supply network heater through a pipeline.

Description

technical field [0001] The invention relates to a cascade energy utilization heating system and a control method thereof under low-load conditions, and belongs to the technical field of thermal power generation. Background technique [0002] With the development of the national economy, the society's demand for electricity is constantly increasing. In the early days, due to the lack of electricity in our country, the main task of the generator set was to generate electricity at full capacity and stably. With the development of electric power in our country, the relationship between electricity consumption and power generation has tended to be balanced, and there will even be a situation of excess power generation. [0003] In addition, the total thermal efficiency of general cogeneration plants can reach 60%-80% in the heating season, and 50%-70% in the whole year. For non-cogeneration units, the thermal efficiency of small and medium-sized extraction condensing or pure co...

AI Technical Summary

Problems solved by technology

The temperature of condensed waste steam is generally 20°C-40°C, which belongs to low-grade heat energy and is difficult to recover

[0004] Condensed waste steam is waste heat for steam turbines in thermal power generation, but it is a serious waste of energy for residential heating with low energy quality requirements

At the same time, the exhaust steam is cooled by the condenser and then released into the atmosphere, which is also likely to cause pollution to the air environment

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