Xinya Pharmaceutical is a large-scale enterprise that produces antibiotic drugs. In 2001, its output value reached RMB 3 billion and realized profits and taxes of RMB 77 million. The plant consumed 16.98 million KWh in 2001, accounting for 60% of the company's total energy consumption, of which the circulating cooling water system consumed 2.14 million KWh (including fans), accounting for 13% of the total power consumption.

  The circulating cooling water system originally consisted of 4 circulating water pumps (with 3 160KW and 1 75KW motors) and 5 500-ton cooling towers (with 5 15KW fans). Usually 3 160KW water pumps are operated with 2 and 1 standby. The annual operation time is about 5000 hours/unit, and the annual power consumption is 1.788 million KWh. The annual operation time of one 75KW pump is about 4000 hours and the power consumption is 243,000 KWh.
  Through field measurement, it is found that there is a lot of energy-saving space. The pump type of this system is unreasonable, and the head is too large; the flow of the pump cannot be adjusted, and the circulating water volume is too large; the cooling capacity of the cooling tower is insufficient. According to the test results and system requirements, we modified the system in 2002. Replace the water pump and cooling tower, the motor is equipped with a frequency converter, and adopts automatic control technology, according to the influence of seasonal changes on the change of circulating water load. Use 1 set of P-T distributed control system to collect dozens of on-site real-time data, analyze and judge by PLC, and run fully automatically.
  The PT distributed control system consists of two LG SV160IH-4 inverters to control the cooling water pump, one SV037IH-4 inverter controls three cooling fans, and the distributed control system composed of LG MARSTK-300 series PLC is connected to the start and stop of the condensing unit. The pressure signal makes the operation of the entire circulating water system more reasonable.
  After the project is completed, the energy-saving effect is quite obvious. Before the transformation, the average power was 269KW, the annual power consumption was 2.14 million KWh, and the annual electricity cost was 1.3 million yuan; after the transformation, the average power was 130KW, the annual power consumption was less than 1.04 million KWh, and the annual electricity cost was 640,000 yuan. The annual electricity saving is 1.1 million KWh, the annual electricity cost is 660,000 yuan, and the project investment recovery period is 1.8 years.