Abstract : This paper introduces the selection of the high-voltage frequency converter retrofit scheme for the blowers of the thermal power plant of Hegang Mining Bureau, and analyzes the system configuration, application and energy-saving benefits of the high-voltage frequency converter using Leadway Co., Ltd.
Keywords : High-voltage frequency converter induced draft fan system configuration
Abstract: The article introduces the selection of transformation solutions of “Lead&Harvest” high voltage inveaer, which is used for blowers in therm al-electric plant in Hegang． The system configuration, applying situation and energy saving benefit analysis are also explained．
Key words : High voltage inveaer Induced draft fan System configuration
1 Introduction
The Hegang Mining Bureau Thermal Power Plant is located in Hegang City, Heilongjiang Province, a major coal-producing city in China. The plant belongs to the mining bureau system and consists of four generating units and six boilers, including two 50MW generator sets and two 25MW generator sets, four 75-ton boilers and two 220-ton boilers. Boilers No. 5 and No. 6 are 220-ton boilers, and boiler No. 7 (another 220-ton boiler) is currently under construction.
In addition to supplying electricity to the Northeast China power grid during winter, the plant is also responsible for providing heating to most areas of Hegang. For a long time, the forced draft and induced draft fan motors of the 220-ton boiler at this power plant have been operating at industrial frequency. The air volume is adjusted by the dampers of the forced draft and induced draft fans to maintain the negative pressure of the boiler. The opening of the fan dampers is generally around 40%. As a result, a large amount of energy is wasted on the fan dampers, causing the plant's power consumption rate to remain high.
In summer, operating only one 220-ton boiler is usually sufficient to meet the load requirements. In winter, to meet heating needs, both 220-ton boilers are typically operated. The feedwater systems for boilers No. 6 and No. 5 use a common pipe system, with one feedwater pump in operation and one on standby. When both boilers are running simultaneously, the feedwater flow and pressure from one frequency-controlled feedwater pump are just sufficient. However, when one boiler is running, one feedwater pump is activated, but its outlet pressure is 15 MPa, while the actual required feedwater pressure is only 12.5 MPa. This outlet pressure is too high and requires adjustment. Because the feedwater pump is driven by a fixed-speed motor, the flow and pressure can only be controlled through boiler-side valves. This is not only economically inefficient but also poses a safety hazard to the feedwater pipeline due to the excessively high feedwater pressure at the boiler.
For details, please click: Case Study of High-Voltage Frequency Converter Retrofit at Hegang Mining Bureau Thermal Power Plant
