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Energy saving in oil processing machine production line
Date: 2023-03-14
Energy saving in oil processing machine production line
Oil is closely related to human life. Oil processing is closely related to the national economy and people's livelihood. Grain and oil production enterprises must not only produce high-quality products to meet national consumption, but also pay attention to energy conservation and environmental protection. This requires practitioners to continuously innovate oil processing technology and serve the society.
Application of high-voltage motors in large-scale oil processing machine production lines; With the increasing production capacity of soybean and other bulk oil processing production lines and the improvement of the environmental power supply voltage level of processing plants, high-voltage motors have also joined the ranks of motor equipment in large-scale oil processing production lines. The general practice is to use high-voltage motors for motors above 160 kW (including 160 kW) (voltage levels are usually 3000, 6000, 10000V, and the latter two are generally used in practical applications). For a 4000 t/d soybean (blank) and 5000 t/d (extruded) extrusion production line, the total installed capacity of 160 kW or more (including 160 kW) motors (about 20 sets) is about 4100 kW or more. Under normal operating conditions, according to preliminary calculations, using high-voltage motors can save about 400,000 yuan in electricity costs per year compared with using ordinary motors, and using high-voltage motors can save about 1.5 million yuan in one-time investment compared with ordinary motors, because the use of high-voltage motors can save transformers and other costs After comprehensive consideration, it is estimated that the investment will be recovered in about 3 years. The author believes that it is worth promoting this technology in the grain and oil processing industry. Of course, this technology has already been applied in grain and oil processing enterprises.
Comprehensive utilization of exhaust steam in the production line of large oil processing machines; due to the low pressure of exhaust steam, only low-pressure equipment can be considered in the direction of comprehensive utilization. According to the theoretical and practical results, exhaust steam is generally heated for the air heat exchanger of the conditioning tower (steam pressure ≤ 0.1 MPa), and can also be used for other lower-pressure steam equipment. The new technology is that if the equipment steam pressure is greater than the exhaust steam In the case of steam pressure, the gas system can be used to help solve it. In addition, if the hot water is not sent back to the boiler for use, it can be used for heat tracing of the compact brake dragon and the expansion system brake dragon.

Utilization of secondary steam in the leaching link of large-scale oil processing machine production line
(1) Use an economizer to directly exchange heat between the uncondensed steam in the first steaming shell and the condensate of the condenser, and then enter the water separator to increase the temperature of the condensate entering the water separator; under normal production conditions, the solvent can be directly heated without preheating into the extractor. (2) The crude oil coming out of the stripping tower exchanges heat with the steamed mixed oil. (3) All steam condensate waste steam in the leaching workshop is preheated to the waste water discharged from the water distribution tank. (4) All steam condensate in the leaching workshop is used for pre-heating of DTDC air heater.
Zero discharge technology for large-scale oil processing machine production line wastewater; as far as the 4000 t/d soybean pressing production line is concerned, the sewage discharge of the leaching workshop is about 15 tons per hour, that is, nearly 350 tons of sewage per day. 99% of the 350 t wastewater comes from the discharge of the workshop wastewater cooking tank. If it is all discharged to the sewage workshop, it will not only save energy but also increase the cost of sewage treatment [1]. By adopting the technology of zero discharge of wastewater, that is, converting all the wastewater into steam by heating, and reusing it in low-pressure steam equipment [2], it is concluded through production practice that the steam consumed by heating wastewater is basically the same as the steam converted from wastewater The amount is comparable. This technology has been applied in China with good results in recent years. In recent years, domestic first-class factories and engineering companies have applied this technology well, and it has become more and more perfect. The key point of the technology is that it requires a high degree of automation. The basic principle is shown in Figure 1.
Large oil processing machine production line DT adds VRS layer technology; VRS is "vapor recovery system". The usual design method is to design the layer directly below the DT steam layer, and the specific method is to use an air pump to spray the steam discharged from the upper rotary valve back to a higher position in the DT. This technology appeared in South and North America in the 1980s. In the past 10 years, some large factories and engineering companies in my country have also used or successfully designed it. The advantages of applying this technology are: it can save 10 kg/t of steam; reduce the loss of solvent by 5%-10%; it can reduce the moisture in DC; it can protect the rotary valve; it can reduce the vapor pressure of DT discharge port.
Vacuum wet cooling technology for deodorization in the refining process of large-scale oil processing machine production lines; in the past 10 years, the general process of vacuum cooling in the deodorization system in the refining process is "hot well + cold water tower". Vacuum wet cooling technology has appeared (see Figure 2), and has been widely promoted.
The basic improvement is to freeze the water in the cooling tower through a refrigerator, and change the cooling water required for vacuum into 5-7°C frozen water, which greatly improves the vacuum effect, and at the same time improves the original large thermal well to occupy a very small area airtight hot well tank. After improvement, the effect of energy saving and environmental protection is obvious. In terms of energy saving: for a 1000 t/d soybean oil refining line, the steam consumption can be reduced from 120 kg/t to 65 kg/t; The phenomenon that the rice can smell the peculiar smell is gone. Finally, the vacuum effect of equipment such as deodorization tower is also better, so the product quality is also improved at the same time [3].
Deodorization vacuum dry cooling technology for large-scale oil processing machine production lines; in recent years, with the continuous research of refining technology, new technologies that are more energy-saving and environmentally friendly have been promoted and implemented, such as deodorization vacuum dry cooling technology, also known as ice cooling technology. Generally, hydrogen is used as refrigerant in many industries, as shown in Figure 3.
The process principle is: at the triple point of water at 0°C, 613.3 Pa, there are only two states of gas phase water and solid phase ice, through the deep cooling (-28°C) generated when liquid ammonia evaporates, the deodorized gas is sucked into the air The water vapor, fatty acid, etc. in the system all freeze instantly, condense directly on the surface of the condenser tube into a solid phase and adhere to the tube surface, and then use the steam jet pump to pump out the non-condensable gas in the system to generate a vacuum in the deodorization tower. After condensation, only air [4] flows to the jet pump. After applying this technology, the effect of environmental protection is similar to that of 3.1 (because this technology is a deepening of wet cooling technology), and the effect of energy saving is more significant. Taking the 1000 t/d soybean oil refining line as an example, the steam consumption can be reduced from the original wet cooling level of less than or equal to 65 kg/t to less than or equal to 45 kg/t. However, the one-time investment of this technology is relatively large, and it is estimated that 800 t The /d refining line can be used as a critical point, that is, if the 800 t/d production line uses this technology to save costs, it will take 4-6 years to recover the investment cost. But it is very suitable for the return on investment of the production line above 800 t/d. There is another suggestion, that is, it is suggested that everyone consider the transformation of the original refining hot well process of more than 600 t/d. According to the engineering practice of several companies, especially the bold attempt to use domestic refrigerators, the one-time investment is greatly reduced. One 1000 t /d's soybean oil refining production line has a total investment and renovation cost of about 6 million yuan (including civil engineering and steel structure), so the investment can be recovered in about 3 years. There are also points that need to be paid attention to during project operation (mainly referring to the design and manufacturing process). The design of the heat exchanger should be easy to clean, and the leakage should be strictly controlled during manufacturing (mainly referring to the tube heat exchanger). If leakage occurs in the valve, the general manufacturer chooses to import this valve, but from a practical point of view, a joint venture brand can also be used. After several engineering practices, the effect is also good. In addition, the ice-cooled vacuum system can stabilize the vacuum degree of deodorization below 200 Pa, thus greatly improving the product quality, and the comprehensive benefits are self-evident.
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