Application of High Pressure VFD (Variable-frequency Drive) in Fermentation Tank Mixer

1 Introduction?

Shandong Zibo Zhongxuan Group Co., Ltd. is an earlier large-scale enterprise in China that produces xanthan gum and other biological products. It has more than 30 years of experience in research, development and production of fermentation, and currently has a production scale of tens of thousands of tons. , passed the iso9002 quality system and international certifications such as kosher, fcciv, usp, etc., formed a global sales network, provided all-round application technology services, and developed into an important production and sales base of biological products in the world.

However, in recent years, with the continuous increase of production and sales, the production cost of enterprises has also been rising year by year, especially for large-scale fermentation tank mixing machines, the electricity bill remains high, which has become a major obstacle to the development of enterprises. Now the Chinese state generally advocates energy saving and consumption reduction. With the promulgation of the "Energy Conservation Law of the People's Republic of China", it is imperative to improve production technology and reduce production costs.

At present, in production enterprises, popularizing and applying frequency conversion and speed regulation, applying power electronic technology, improving power consumption efficiency, improving production process, realizing automatic control, and then saving resources, reducing production costs, and reducing labor and power consumption have become enterprises. main stream of development. Especially in recent years, with the improvement of high-voltage frequency conversion speed regulation technology, the application of high-voltage VFD (Variable-frequency Drive) is becoming more and more popular. Therefore, using high-voltage frequency conversion to carry out technical transformation on the original power frequency control equipment and new equipment has become a top priority. After repeated deliberations and discussions, the leaders of Shandong Zhongxuan Group Co., Ltd. decided to carry out technical transformation on the 10 sets of equipment in the second phase of the current xanthan gum fermentation tank mixer, apply mature high-voltage frequency conversion speed regulation technology, and eliminate many Pole electromagnetic speed regulating equipment has achieved good technological and energy-saving effects.

After investigation, Chengdu Sunwoele Co., Ltd. is an early research and production unit of VFD (Variable-frequency Drive) in China, with more than ten years of research and development experience, especially in the production of high-voltage VFD (Variable-frequency Drive) , with strong strength, won the "China Famous Brand" product in 2007, and is the only enterprise unit that drafted and approved the Chinese national standard for high and low voltage VFD (Variable-frequency Drive). The high-voltage VFD (Variable-frequency Drive) developed and produced has been widely used in many famous industries such as steel, coal, chemical, petroleum, and pharmaceutical industries in China. It has been applied in batches to dust removal fans, condensate pumps, hoists and other equipment in Laiwu Steel, Liaohe Oilfield, Shengli Oilfield, Jigang, Pingyin Pharmaceutical Factory, Inner Mongolia Coal Mine, etc., and achieved good results, so they decided to use it The 10kv/630kw high-voltage VFD (Variable-frequency Drive) produced by Chengdu Sunwoele Co., Ltd. underwent equipment transformation.

2 On-site equipment conditions

2.1 Equipment situation

(1) Motor parameters

Rated power: 450kw;

Rated current: 29a;

Rated voltage: 10kv;

Rated frequency: 50hz;

Power factor: 0.89.

(2) Operating parameters

Start mode: direct start;

Working current range: 24~35a;

Annual working hours: 7500h;

Working cycle: 70～72h;

Electricity price: 0.45 yuan/kw·h.

(3) Working condition details

The working cycle is 72 hours, which can be adjusted according to the process requirements. It is driven by a belt, and slipping may occur when running at high speed. The stirring speed is about 120r/min. In each working cycle, in the first 0~48h, it is multi-pole speed regulation, and the maximum speed adjustment range is 40% of the rated speed. The operating frequency is about 30hz in the early stage, 40hz at 24h, and 45hz after 48h.

2.2 Determination of the design scheme

In order to meet the VFD (Variable-frequency Drive) requirements in the high-voltage frequency conversion configuration, a careful analysis has been carried out in line with the policy of safety first and reliable quality. The following technical scheme, this scheme has the following characteristics:

(1) Excellent speed regulation performance, meeting the load process requirements;

(2) Good energy-saving effect, improving system operation efficiency;

(3) Realize the soft start of the system, reduce the start-up impact, reduce maintenance costs, and prolong the service life of equipment;

(4) The system is safe and reliable to ensure the continuous operation of the load;

(5) The control is convenient and flexible, and the automation level is high.

During the design, a high-voltage VFD (Variable-frequency Drive) was selected according to the motor capacity to control the mixer system. The original design motor capacity was 10kv/450kw, so the HFV1000 high-voltage VFD (Variable-frequency Drive) produced by Chengdu Sunwoele Co., Ltd. was selected. Drive) to control. For the sake of safety, to prevent production from being delayed during VFD (Variable-frequency Drive) maintenance or failure, the system is also designed with a power frequency bypass, which can realize automatic conversion of power frequency drive.

2.3 Main technical performance indicators

Rated input voltage: 10kv (-20%～+15%);

Input frequency: 45~55hz;

Input mode: 36-pulse diode full-wave rectification input;

Output mode: 10 unit carrier phase-shifted sine wave pulse width modulation output for each phase;

Input power factor: greater than 0.96 (at rated load);

Efficiency (including transformer): greater than 96% (at rated load);

Output frequency: 0~50hz, continuously adjustable;

Frequency resolution: 0.01h