Bypass grading coal economizer system with active exhaust gas temperature control function

Abstract

The invention discloses a bypass grading coal economizer system with the active exhaust gas temperature control function. The system comprises a high-temperature coal economizer, a front air preheater and a bypass grading device. The high-temperature coal economizer and the front air preheater are arranged at the upper portion and the lower portion of a flue respectively. The bypass grading device is arranged between the high-temperature coal economizer and the front air preheater and comprises a control valve, a main air preheater, a bypass coal economizer high-temperature section and a bypass coal economizer low-temperature section. The flue is divided into a main flue body and a bypass flue body through the control valve, the main air preheater is located on the main flue body, and the bypass coal economizer high-temperature section and the bypass coal economizer low-temperature section are located on the bypass flue body up and down. By the adoption of the bypass grading coal economizer system, the control valve is additionally arranged to divide the flue into the main flue body and the bypass flue body, so that the separated flue is formed, exhaust gas waste heat is used grade by grade, and the exhaust gas temperature is actively controlled.

Description

technical field [0001] The invention belongs to the technical field of boiler exhaust gas temperature control, and more specifically relates to a bypass graded economizer system for actively controlling the exhaust gas temperature. Background technique [0002] At present, the heat loss of the boiler exhaust gas accounts for the largest proportion (about 5% to 7%) of the various heat losses of the boiler, and the high temperature of the boiler exhaust gas will seriously affect the economic operation of the boiler. In the actual operation of coal-fired generating units, the degree of pollution of the heating surface increases with the operating time of the boiler, resulting in the exhaust gas temperature of the long-term operating boiler being 10°C to 30°C higher than the design temperature. The exhaust gas temperature of large thermal power unit boilers is mostly between 125 and 145 °C, and with the change of ambient temperature, the exhaust gas temperature may have further ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above defects or improvement needs of the prior art, the present invention provides a bypass graded economizer system that actively controls the exhaust gas temperature, wherein combined with the characteristics of the economizer system itself, a corresponding design that can actively control the exhaust gas temperature Bypass graded economizer system, and its key components such as the structure of bypass grader and its specific setting method are studied and designed, which can effectively solve the problem of large heat transfer temperature difference and smoke exhaust in existing low temperature economizers. The temperature cannot be controlled, and at the same time, it can also realize the hierarchical utilization of exhaust heat

Images