中文版 ENGLISH
NEWS
NEWS Your current location:Home > News
DHC: Energy Conservation “Template” of Frequency Conversion Reconstruction of Coal and Electricity Feed Pump2012-06-11

Reporter Yu Haijiang
 

On October 7, 2011, the frequency conversion reconstruction project of the No.1 turbine unit electrically driven feed pump of Datang Shuangyashan Thermal Power Co., Ltd. assumed by Dongfang Hitachi (CD) Electrical Control Equipment Co., Ltd. (DHC) was formally put into operation. Under the operation condition of the average load rate of 76%, the power saving rate reaches 21%; the energy saving effect is obvious. This technology has achieved another major breakthrough of the frequency conversion and energy saving application of the power plant feed pump system, initiating a first in the application of the VVVF multi-function hydraulic coupling technology in domestic and international power generation companies.
 

In fact, as early as March 2010, relying on the technology and engineering application experience accumulated in the frequency conversion reconstruction project of the draught fans of 200,000kW, 300,000kW, 600,000kW, 1 million kW coal and electricity units, DHC completed the country's first frequency conversion and energy saving reconstruction project of the 300MW thermal power generating unit high-power feed pump in the power plant of Meizhou Bay, Fujian Province which  has been running smoothly after being put into operation and the power saving rate reached 30%. In May this year, the 2nd phrase project of the reconstruction of the power plant feed pumps in Meizhou Bay once again selected DHC high voltage inverter. The annual coal saving quantity can reach up to 19,414 tons after the frequency conversion reconstruction of the four pumps is completed.
 

"The successful demonstration of the frequency conversion reconstruction of DHC electrically driven feed pump set a significant reference for the upgrading of our country's old units with 10 million installed capacity; if it is widely used in our country's 200,000kW or similar power plant with 100% capacity feed pump in the form of ‘one for use and one for back-up, huge energy can be saved", said Liu Shihong, the production vice manager of Datang Shuangyashan Thermal Power Co., Ltd., in an interview by the Electric Weekly.
"Pioneer" of Frequency Conversion Reconstruction
 

In September 2006, the 2 turbine generator units with installed capacity of 200,000kW of Datang Shuangyashan Thermal Power Co., Ltd. have been successively put into operation. Each unit was set up with two electrically driven feed pumps of 100% capacity in one for operation and the other for standby. Till 2010, the calculated results showed: the power consumption of the two units feed pumps accounted for 2.2% of the generated energy, and accounted for nearly 30% of the power consumption rate of the generation plant which directly affected the power supply coal consumption, the cost of power generation and energy consumption.
 

The power consumption of the feed pump is the most in the main auxiliary engines of the power plant. Therefore, the optimization and reconstruction of the speed control pattern of the electrically driven feed pump is quite essential.
 

"In order to implement the energy saving requirements proposed by the country and Datang Corporation and reduce the power consumption of the electrically driven pump, annual operating costs, as well as the power supply coal consumption, after the full survey by Datang Shuangyashan Thermal Power Co., Ltd., the fluid coupling was reconstructed into multi-function fluid coupling", Liu Shihong said.
 

The same situation occurred in the power plant of Meizhou Bay, the turbine feed water circuit of this power plant was designed to be three electrically driven condensate pumps with 50% capacity, two electrically driven constant speed feed pumps of 5740 kW/6 kV with 70% capacity (no fluid coupling speed control and backup feed pump); the feed water control of the boiler only adjusts the drum water level through the control valve opening for throttling of water supply which resulted in high power consumption rate and coal consumption of the unit plant. In order to comply with the energy saving and environmental protection policy and effectively control the cost of power generation, the frequency conversion reconstruction of the two feed pumps of the No. 2 unit was put on the agenda in early 2009.
 

A summary report of the power plant in Meizhou Bay shows: "It is very common to apply frequency converter in the speed control of the auxiliary equipment of thermal power generating unit, but the output power of the frequency converters used in these successful examples are generally less than 3000kW. The application of the 5700kW frequency converter to the reconstruction of the speed control of the feed pump is the first time, and the water supply system design of the reconstruction unit is unique in the country. The project selected efficient, energy saving, pollution free Hitachi high-voltage high-power frequency conversion equipment, and brought VVVF system into the DCS system of the unit, and finally realized the automatic control of VVVF system and feed pump motor speed.”
 

It is no exaggeration to say that DHC has provided an energy saving template for the integrated upgrading of our country's coal and electricity units; the former created a new era of the reconstruction technology of the country's first coal-fired unit VVVF type fluid coupling electrically driven feed pump; the later applied 5700kW frequency converter to the reconstruction of the speed control of the feed pump which was also the first time in the country and the water supply system design of the reconstruction unit was unique in the country.
 

Creating Energy Saving "Template"
 

"It has been more than six months since the frequency conversion reconstruction of the two feed pumps of Datang Shuangyashan Thermal Power Co., Ltd. put into operation. During the operation, the energy saving effect was remarkable; the calculation and comparison of the actual statistics data showed that: the tested power saving rate on October 15, 2011 was 19.9%. Till December 30, 2011, the energy saving volume of No. 1, 2 feed pump was tested again; during this period, the load of the two units was 150,000kW, the load rate about 75%, the power saving rate is 20.35%; if calculated according to the number of hours operated in 2011, i.e. 6804 hours and the annual power saving is 5,178,677kWh, it would increase output value of 2.0403 million yuan/year, which amounts to standard coal 3506 tons/year", said Liu Shihong.
 

Similar to the situation of energy saving and stable operation of Datang Shuangyashan Thermal Power Co., Ltd., the two feed pump frequency converters of the No. 2 unit of the power plant of Meizhou Bay have been running for more than two years; during the period, there was no failure of the converter components; the power supply coal consumption continued to reduce and most of the frequent breakdowns of the equipment were eliminated which improved the stability and reliability of the system. The annual power consumption rate decreased by 0.23% and saved 9.2 million kWh of electricity; the reduced heat loss was equivalent to 6883.92 tons of standard coal and the annual savings of standard coal was 9707 tons. The total investment of the two pump frequency conversion devices is about RMB14 million yuan and it has been fully recovered within 17 months", said the related person in charge of the power plant of Meizhou Bay.
 

"There is a precedent of 200,000kW of turbine unit feed pump frequency control. From the perspective of power saving, they are equally matched, but from the prospective of safety, reliability, convenience and flexibility and adapting to the site need, the technological reconstruction of VVVF type fluid coupling electrically driven feed pump is undoubtedly perfect ", said Liu Shihong.
 

Differ from the two 200,000kW turbine generator units of Datang Shuangyashan Thermal Power Co., Ltd., each unit set up with two electrically driven feed pumps of 100% capacity, one in operation and the other for backup, the 2x396,000kW units of the power plant of Meizhou Bay are one unit set up with two feed pumps, a single feed pump with 70% load, two feed pump in constant speed running, no backup. Although the operation mode of the feed pumps of the above two reconstruction projects is different, the optimization, design and reconstruction through the frequency conversion technology of DHC have made very significant energy saving effect, so it can be called an energy saving "template".
 

In addition to the reconstruction demonstration effect of the frequency conversion and energy saving which the project itself possesses, it also has some guiding significance for the domestic power plants to design and select model for the feed pump. The energy saving practices of electrically driven feed pumps with different operating modes prove that: the electrically driven feed pump starts quick, with stable and reliable running, simple system configuration, low maintenance work, highly economical; it is more efficient than the steam feed pump and has remarkable energy saving rate, therefore the electrically driven feed pump is better than the steam feed pump that it should be vigorously promoted.
 

At the moment, the integrated upgrading of our country's coal and electricity units is in full swing, DHC, as an early company in our country which grasps the core technology of high voltage inverter, had created a new record of China-made high-power frequency converter devices since 2000 and continues to push the industrialization of the high voltage inverters to provide the energy saving "sample" which is worth learning and promoting for the frequency conversion and reconstruction of our country's coal and electricity unit high-power electrically driven feed pump.

Dongfang Hitachi (Chengdu) Electrical Control Equipment CO., LTD 蜀ICP备11011855号
Power by:35.com