New mode of frequency conversion and energy saving

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The new mode of frequency conversion and energy saving in production expansion and transformation

Sinopec Shijiazhuang refining and chemical branch is an oil, chemical and fiber integrated production enterprise. As a large fuel chemical refining enterprise with 22 sets of production units, including 5million T/a atmospheric and vacuum distillation, 2million T/A heavy oil catalytic cracking, 800000 T/a delayed coking, in order to meet the growing market demand, the factory decided to expand and transform the production line, The output of caprolactam will be increased from 65000 T/A to 160000 T/A. various energy-saving processes will be fully utilized in the expansion and reconstruction, and one 630kw and 800KW frequency converter will be installed in the reconstruction of circulating water plant

it is inevitable for enterprises to carry out frequency conversion transformation of the cooling tower. Director Zheng Xuping of the electrical workshop of the chemical business department of Sinopec Shijiazhuang refining and chemical branch explained that because there are many heat exchangers in the factory that need to be cooled by circulating cooling water devices, fans and pump loads previously driven by power frequency mainly regulate the air volume or flow through dampers or valves, and the motor still operates at the rated speed, The energy consumption of the motor is basically the same as that under rated working conditions. When the operating point of the motor is far away from the high efficiency point, a large amount of throttling loss is wasted on the damper or valve. Therefore, as a pressure closed-loop control system, the frequency conversion speed regulation of circulating water pump can set the pump outlet pressure as the control parameter. If the actual pressure deviates ± Δ P, the output frequency is automatically adjusted, and the outlet pressure of the pump is changed, so that the outlet pressure of the pump basically maintains the set pressure value, which is different from the original method of controlling the opening of the outlet valve. Variable frequency speed regulation can achieve high efficiency and energy saving, and there is no throttling loss

energy saving transformation: according to the estimation of the enterprise, the high-voltage frequency conversion transformation of circulating cooling water pump will produce considerable direct and indirect economic benefits. Taking a 6kV frequency converter as an example, the frequency converter and its auxiliary control and monitoring system need about 1.9 million yuan, with an average of about 2300 yuan/kw. It is estimated that the average electricity can be saved by about 30%

in addition, after adopting variable frequency drive, the motor can realize soft start, which avoids the current impact and torque impact on electricity during power frequency starting. When the air volume or flow decreases, due to the decrease of motor speed, the wear of fan blades of fans or pumps and the wear of pipes will be reduced, which can greatly extend the service life of motors, contactors and mechanical parts, bearings, valves and pipes, reduce the maintenance workload and reduce the maintenance cost. At the same time, due to the perfect protection and control function of the frequency converter, the status of the motor can be fed back to the upper control system in time to improve the control level of the circulating water system

good solutions need better products.

after deciding to carry out frequency conversion transformation, the two things that enterprises need to do are the selection of frequency converters and the determination of purchase methods. Director Zheng Xuping said that refining and chemical enterprises have complex processes and use a large number of electrical equipment, so solving electrical harmonic pollution is the focus of frequency converter selection. Secondly, the failure of the frequency converter will lead to the shutdown of the whole unit, and the resulting loss of economic and social benefits is far from the value of the frequency converter itself. "Safety and reliability" is also the key to the investigation. Sinopec Shijiazhuang refining and chemical company has discussed the selection of frequency converter suppliers for many times. Based on the above two requirements, after strict screening, it finally decided to use Siemens robinham pH series high voltage frequency converter. Director Zheng Xuping said, "this choice was made because robinham's products have many advantages and the comprehensive results of timely and comprehensive after-sales service."

Li Fenglei, a senior sales representative in the Northern District of Siemens (China) industrial automation and drive technology group, said that pH belongs to Siemens robinham perfect harmonic free series high-voltage inverter. Due to the 36 pulse multiple rectification input mode, it can directly eliminate the input harmonics below 35 times without using the input filter, which will not pollute the electricity and affect the normal operation of other equipment on the same power supply, Eliminating harmonic pollution is the main demand of the factory for products

the comprehensive advantages in safety, reliability and other performance are also Siemens' decisive chips. Li Fenglei said that Siemens robinham has changed its focus from product feasibility. 2. Economy: reliability to process reliability, and has more consideration on how to ensure the uninterrupted production process when the service conditions change. For example, it has developed functions such as unit bypass, center point drift and expanded undervoltage protection. When there is a power unit failure or serious fluctuations in electric voltage, the frequency converter can continue to operate continuously, Thus, some important processes are not interrupted, and the safe and reliable operation of the system is ensured

in terms of after-sales service, Shilin manager of Hebei and Shanxi offices of industrial automation and drive technology group of Siemens (China) Co., Ltd. is full of confidence. After the acquisition of robinham, Siemens has truly achieved a strong combination in the field of high-voltage variable frequency speed regulation, that is, to combine the technical progressiveness of robinham products with Siemens' strong sales and service system. "Siemens industrial automation and drive technology group has more than 60 offices in China. Our goal is to serve customers from zero distance and provide customers with faster service response." Stone forest manager said

quasi energy management innovation win-win mode

it should be noted here that in terms of the purchase method of frequency converters, Sinopec Shijiazhuang refining and chemical branch and world wide Innovation Corporation have made a new attempt by using the relevant national energy-saving incentive and subsidy policies. Song Li, general manager of world wide innovation, explained that world wide innovation provides energy-saving solutions and ensures energy conservation, Siemens provides energy-saving products and technologies, and world wide innovation purchases equipment from Siemens and pays the payment to Siemens in a lump sum. Shijiazhuang refining and chemical only pays 80% of the amount to wanwei innovation before the equipment is installed and put into operation, and then pays the remaining 20% of the balance to wanwei innovation after the equipment is operated and reaches the energy savings agreed in the contract

general manager Song Li believes that this mode can help enterprises overcome the concerns and doubts that the economic benefits of energy-saving projects are not fire-resistant and burn through resistant, and occupy too much energy of enterprises. World wide innovation can also improve the operation ability of energy-saving projects and reduce the implementation cost of energy-saving projects through the development and a large number of "replication" of similar projects. In this business model, to a certain extent, world wide innovation exercises the responsibility of the energy-saving service company in the contract energy management. This project can also be called the quasi contract energy management model. The adoption of this model truly realizes the goals of Shijiazhuang refining and chemical, Siemens, world wide innovation and environmental win-win

as the equipment supplier of this project, Siemens has many advantages. As the world's leading energy-saving and environmental protection enterprise, Siemens' energy-saving business portfolio covers the whole energy supply chain, from power generation, transmission, distribution to industrial and civil efficient power consumption. "With our world leading technology and experience in various fields, we can provide customers with fully integrated energy-saving solutions. Customers no longer need to seek different solutions from different companies and try to integrate them, which can help customers save a lot of time and money." Stone forest manager said

director Zheng Xuping said that the reason why the circulating water plant of Sinopec Shijiazhuang refining and chemical branch chose this operation mode was not only the low risk, but also the trust in the reputation of partner wanwei innovation and Siemens brand. In the energy-saving transformation project, world wide innovation has provided the whole process service for the project, supported by advanced energy conservation and products. At the same time, Shijiazhuang refining and Chemical Co., Ltd. can improve cash flow, invest limited funds in other higher priority investment fields, and enhance competitiveness. Zheng Xuping's electrical workshop (Figure 1) has also received more professional and leading energy-saving information and energy management experience from world wide innovation and Siemens in this technological transformation

Figure 1 the employees in the electrical workshop of Sinopec Shijiazhuang refining and chemical branch achieve the plant's energy-saving goal through equipment operation

the increasing situation and policy support for energy conservation and emission reduction will speed up the promotion of energy-saving transformation projects. According to general manager Song Li, according to the notice of Shijiazhuang Industrial Economic Promotion Bureau on applying for 2008 power demand side management projects, Frequency conversion and speed regulation power saving technology is a key power saving project to be promoted. Units can declare this power saving project and enjoy the subsidy of provincial special financial funds, specifically 1kW power saving, and the provincial financial subsidy of 1700 yuan. Shijiazhuang refining and chemical project enjoys this policy subsidy. Wanwei innovation bears certain risks and burdens. It is responsible for procurement and construction monitoring, and is under the pressure of realizing the commitment to save energy. The company is optimistic about the energy-saving market

Sinopec Shijiazhuang refining and chemical company has tasted the benefits of frequency conversion transformation. In addition to the reasonable radial load distribution of the bearings of the two frequency converters that have been used in the circulating cooling water pump of the cooling tower, the company has decided to purchase an additional Siemens Robicon high-voltage frequency converter through world wide innovation for the energy-saving transformation of the induced draft fan speed regulation system, and the benefits and impacts are only just beginning. (end)

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