Abstract: At present, vacuum technology is widely used in petroleum, chemical, pharmaceutical and other industries by vacuum evaporation, crystallization, distillation, sublimation, drying, vacuum concentration, dehydration, chemical reaction absorption and vacuum conveying materials, After the application of vacuum technology in the process of processing, it can save energy, speed up the reaction, improve product quality and increase economic benefits. Gradually, the vacuum technology is a scientific edge. The vacuum industry in our country digested and absorbed the former Soviet Union and the United States , Japan, Germany, developed on the basis of the product, although in recent years the number of vacuum equipment manufacturers in China have mushroomed, but many manufacturers for its production of vacuum pumps in different processes how to use selection is not clear (Let alone on the basis of the user to provide technical parameters for new product design), which gives the user a lot of inconvenience selection, this article will be based on my company more than 30 years of production, development and supporting experience, described in the chemical industry Several typical technology how to choose the jet vacuum pump problem.
First, several concepts on the vacuum pump
How to apply a good vacuum pump in the process of chemical production, you need to clearly define the following concepts:
1. The concept of "vacuum": "Vacuum" refers to the state of gas below a single atmospheric pressure in a given space, that is, the density of gas molecules in the space that is lower than the atmospheric pressure of that area. The state of space without gas is called absolute vacuum.
2, vacuum pump: is used to produce, improve and maintain the vacuum device.
3, the amount of pumping: the vacuum pump in the working pressure per unit of time pumping gas flow. Unit: kg / h or m3 / h;
4, the ultimate pressure (vacuum): vacuum in the case of zero extraction vacuum pump can achieve the absolute pressure. Units: Pa, KPa, MPa or mmhg (ultimate pressure minus the local atmospheric pressure for the ultimate vacuum);
5, the working pressure (vacuum): jet pump in the absolute amount of exhaust extraction pressure. Unit: Pa, KPa, MPa or mmhg (working pressure minus the local atmospheric pressure for the work of vacuum);
6, the work of steam pressure: steam jet vacuum pump working steam pressure. Unit: MPa or kgf / cm2;
7, the work of steam consumption: steam jet vacuum pump steam consumption per unit time. Unit: kg / h;
8, cooling water temperature: water jet pump circulating water temperature or steam jet vacuum pump condenser circulating water temperature. Unit: OC;
9, the amount of cooling water circulation: per unit time through the water jet or steam jet pump condenser circulating water flow. Unit: kg / h;
Second, the chemical industry, several common vacuum pumps and their advantages and disadvantages
1, several commonly used in the chemical industry vacuum pump - the chemical industry common vacuum pump can be simply divided into variable volume vacuum pump and jet vacuum pump, variable volume vacuum pump is the use of pump chamber cycle to complete the change of inspiration and exhaust Of the device, reciprocating vacuum pump, rotary vane vacuum pump, slide valve vacuum pump, water ring vacuum pump, Roots vacuum pump is a variable volume vacuum pump. Jet vacuum pump is the use of Venturi effect of high-speed jet pressure drop generated by the gas delivered to the exit of a momentum transfer pump, water jet vacuum pump, steam jet vacuum pump, steam jet spray pump in series, soda spray jet pump belong to the same combination of vacuum pumps.
2, variable volume vacuum pump working principle and advantages and disadvantages
(1) Reciprocating vacuum pump, rotary vane vacuum pump, slide valve vacuum pump, Roots vacuum pump is the piston reciprocating or rotating the gas inhalation, compression and discharge. Their advantage is that the new pump has a relatively high degree of vacuum, but the piston is a running part, so piston wear can not be avoided, as the number of maintenance increases the working vacuum will continue to decline until it can not meet the production requirements. Such pumps work noise, fuel consumption, high failure rate is also a fatal shortcoming, generally need to open a spare one, which virtually increases the equipment investment and operating costs. In addition, if such a pump is used to suck a condensable gas such as steam to emulsify the lubricating oil, it can only be applied to suction of non-condensable (air-based) gas or to suction of a granular medium It also limits its scope of application.
(2) water ring vacuum pump is installed in the pump shell with a multi-vane eccentric rotor rotation, the water thrown into the pump shell to form a concentric water ring with the pump, water ring and rotor blades to form a volume cycle so that the Gas is drawn in, compressed and drained. It has the advantage of low vacuum pumping capacity, you can directly suction steam condensable gas. Its disadvantage is the low degree of vacuum; can not be aspirated with the granular media; rotor rotation is not easy to do anti-corrosion treatment, it can not be aspirated with corrosive media.
3, jet vacuum pump working principle and advantages and disadvantages
Jet vacuum pump is the use of Venturi effect of pressure drop generated by high-speed jet to the gas delivered to the outlet of a momentum transfer pump. It is divided into water jet vacuum pump, steam jet vacuum pump, steam injection pump in series, steam jet spray combination. Jet vacuum pump with its wide range of vacuum, you can directly suction steam and other condensable gas and granular media, simple structure, easy operation, no maintenance of small operating parts, energy saving and other advantages of more and more widely The application of chemical operations in the various processes, the following describes the working principle of various jet vacuum pump.
(1) water jet vacuum pump working principle and structure diagram
Water jet vacuum pump equipment, see the composition of its structure diagram, the working principle is: circulating water in the water tank after circulating pump work to produce a certain pressure, flow rate, with a certain pressure, the flow of water into the water ejector collector, Jet through a plurality of Laval nozzles on the orifice plate to form a high-speed jet to generate a vacuum in the mixing chamber of the ejector. The drawn medium enters the ejector mixing chamber under the action of a vacuum, fully mixed with the high-speed water flow in the mixing chamber, In the tube deceleration, pressurized discharge to the circulating water tank, non-condensable gas precipitation, condensable gas overflow overflow from the tank overflow, so repeatedly work. Its advantage is low machine type, higher than the water ring vacuum pump vacuum, instead of W-type reciprocating vacuum pump can cancel the front condenser, saving one-time investment in equipment and operating costs.
(2) Soda in series injection vacuum pump working principle and structure diagram
In front of the jet ejector of the water jet vacuum pump, one or more steam injection vacuum pumps, that is, a soda jet vacuum pump, are connected in series in front of the jet ejector of the water jet vacuum pump. The structure thereof is shown in the soda jet vacuum pump. The working principle is: a certain pressure of saturated or superheated steam through the Laval nozzle decompression rate of increase into the steam ejector mixing chamber, the mixing chamber to produce a vacuum, the pumping medium is drawn into the mixing chamber and the working steam mixing, mixing After the fluid through the diffuser, the speed decreases, the pressure rises until it reaches the next stage suction pressure into the next stage after the steam jet pump or water jet pump. It is a low level machine type, the vacuum is relatively high, can replace the water ring - Roots unit, Rotor - Roots direct suction condensable vapor, but it is pumping in a high vacuum non-condensable gas is limited .
(3) new high efficiency steam jet vacuum pump working principle and process flow chart
The new high-efficiency steam jet vacuum pump is composed of one or more steam jet pumps and high-efficiency condensers. The saturated or superheated steam of a certain pressure is reduced in pressure through the Laval nozzle to enter the mixing chamber of the steam ejector to cause the mixing chamber to generate In the vacuum, the drawn medium is sucked into the mixing chamber to be mixed with the working steam. The mixed fluid passes through the diffusion tube, the speed drops, and the pressure rises until the pressure of the next stage suction port reaches the next stage steam ejector. After the mixed fluid exiting the steam ejector in front of the condenser enters the high efficiency condenser, the condensable fluid is cooled into liquid with the non-condensable gases and out of the condenser with the cooling water (see the flow chart of the new high efficiency steam jet vacuum pump) . It can be installed at any height. It is suitable for pumping media with relatively small amount of non-condensable gas, most of which can be made into condensable vapor. It can save more than 60% of working steam instead of the traditional multistage steam jet vacuum pump.
(4) Fizzy combination jet vacuum pump working principle and process flow chart
It is in the traditional steam jet pump behind the first-class condenser in series with a cascade of jet vacuum pump and composition, the working principle of the combination of jet fuel jet vacuum pump process flow diagram. It overcomes the shortcomings of the steam jet vacuum pump and the water jet vacuum pump, and exerts their advantages, which can not only achieve a higher working vacuum but also have a larger pumping capacity than the conventional multistage steam jet vacuum pump to save working steam More than 50%, saving more than 30% of cooling water, without the need to start the pump, evacuation tower time is short.
(5) Multi-stage steam jet vacuum pump has the advantages of simple structure, convenient use and stable and reliable operation. The disadvantage is that the steam consumption is high (operation cost is high) and must be installed above 11m.
Third, a reasonable selection of vacuum pumps
In the chemical production process, according to the specific work required by the work pressure level and the nature of the suction gas to choose a reasonable vacuum pump, generally determine the specific process required pressure, vacuum distillation, distillation, sublimation and other processes required vacuum Degree of high (low pressure), vacuum evaporation, drying, condensation, crystallization, dehydration, bleaching, chemical reaction absorption and vacuum conveying materials and other processes require a low degree of vacuum (high working pressure). Working pressure is determined, according to the size of the amount of suction and the nature of the suction gas to choose a reasonable vacuum pump.
1, according to several types of vacuum pump work pressure can be achieved to list the scope of application of various vacuum pumps.
2, choose different suction vacuum gas jet pump
(1) water jet vacuum pump is suitable for working pressure greater than 25mmhg (3.3KPa), sucking a variety of gases, especially in pumping condensable gas (ie condensation in water or condensed condensate gas), with dust , The advantage of granular media is more prominent. When the work pressure is relatively small, non-condensable pumping gas volume is larger, you should choose steam jet pump and steam in series, steam jet spray combination.
(2) The working pressure of series water jet vacuum pump can reach 2mmhg (267Pa), but it is smaller than the new type high efficiency steam jet vacuum pump, steam jet water jet vacuum pump and multistage steam jet vacuum pump, which is suitable for batch production of small and medium-sized enterprises.
(3) The new high efficiency steam jet vacuum pump working pressure can reach 0.5mmhg (65Pa), suitable for most of the gas to be aspirable condensable gas, non-condensable gas occupies a relatively small proportion of the process.
(4) The working pressure of the soda ejector vacuum pump and multistage steam ejector vacuum pump can reach 10Pa, and can suck various gases. The difference between them is that the soda ejector vacuum pump saves the working steam consumption and saves the operation than the multistage steam ejector vacuum pump cost.
Fourth, some of the typical process of application manufacturers
Application manufacturers | Application process | Application products |
Rugao Double Horse Chemical Co., Ltd. | Evaporate in vacuo | Water jet vacuum pump instead of three steam jet vacuum pump |
Rugao Double Horse Chemical Co., Ltd. | Fatty acid vacuum distillation | New High Efficiency Steam Jet Vacuum Pump Replaces Four Steam Injection Vacuum Pumps |
Zhangjiagang Haobo Chemical Co., Ltd. | Evaporate in vacuo | Stainless steel water jet vacuum pump to replace the three-stage steam jet vacuum pump |
Zhangjiagang Haobo Chemical Co., Ltd. | Chemical reaction, absorption | Carbon steel lined fluoroplastic water jet |
Lushun chemical plant | Various crafts | Various jet pump |
Dalian Chlorate Factory | Vacuum crystallization | Combined water jet pump |
Jiangsu Dingding Chemical Co., Ltd. | Fatty acid vacuum distillation | Intercooled soda combined jet vacuum pump instead of four steam jet vacuum pump |
Jiangsu Dingding Chemical Co., Ltd. | Glycerin vacuum distillation | Intercooled soda combined jet vacuum pump instead of four steam jet vacuum pump |
Tianjin Hengbida | Vacuum distillation | Corrosion-resistant soda series injection vacuum pump |
Fushun Qingwei Chemical Co., Ltd. | Evaporate in vacuo | SSP-type water jet vacuum pump |
Datong Samsung Liyuan carbon plant | Absorption and delivery | A steam jet pump |
Nanjing Tate Chemical Equipment Co., Ltd. | Various crafts | Supporting a variety of jet pump |
Gongzhuling Huanglong Food Industry Co., Ltd. | Three-effect evaporation | Two steam jet pump instead of Germany imported two steam jet pump |
Sichuan Mianyang Peng Sheng biochemical plant | Vacuum distillation | New high-efficiency steam jet vacuum pump |
Helen City, the original oil plant | Vacuum deodorization | Three-stage steam jet vacuum pump instead of four steam jet vacuum pump |
Zhangjiagang Zhongding Additives Co., Ltd. | Vacuum distillation | Steam series injection vacuum pump instead of water ring Roots unit |
Fifth, the conclusion
With the constant development of commodity economy and the constant prominence of energy issues, all enterprises have become an important means of increasing their core competitiveness by saving energy and reducing consumption, improving production efficiency and improving product quality. In the various processing processes, a suitable jet vacuum pump , Reduce operating costs, will increase the core competitiveness of enterprises a powerful measure, I hope this paper on the rational use of vacuum pump business played a certain reference.
Application manufacturers
Application process
Application products
Rugao Double Horse Chemical Co., Ltd.
Evaporate in vacuo
Water jet vacuum pump instead of three steam jet vacuum pump
Rugao Double Horse Chemical Co., Ltd.
Fatty acid vacuum distillation
New High Efficiency Steam Jet Vacuum Pump Replaces Four Steam Injection Vacuum Pumps
Zhangjiagang Haobo Chemical Co., Ltd.
Evaporate in vacuo
Stainless steel water jet vacuum pump to replace the three-stage steam jet vacuum pump
Zhangjiagang Haobo Chemical Co., Ltd.
Chemical reaction, absorption
Carbon steel lined fluoroplastic water jet
Lushun chemical plant
Various crafts
Various jet pump
Dalian Chlorate Factory
Vacuum crystallization
Combined water jet pump
Jiangsu Dingding Chemical Co., Ltd.
Fatty acid vacuum distillation
Intercooled soda combined jet vacuum pump instead of four steam jet vacuum pump
Jiangsu Dingding Chemical Co., Ltd.
Glycerin vacuum distillation
Intercooled soda combined jet vacuum pump instead of four steam jet vacuum pump
Tianjin Hengbida
Vacuum distillation
Corrosion-resistant soda series injection vacuum pump
Fushun Qingwei Chemical Co., Ltd.
Evaporate in vacuo
SSP-type water jet vacuum pump
Datong Samsung Liyuan carbon plant
Absorption and delivery
A steam jet pump
Nanjing Tate Chemical Equipment Co., Ltd.
Various crafts
Supporting a variety of jet pump
Gongzhuling Huanglong Food Industry Co., Ltd.
Three-effect evaporation
Two steam jet pump instead of Germany imported two steam jet pump
Sichuan Mianyang Peng Sheng biochemical plant
Vacuum distillation
New high-efficiency steam jet vacuum pump
Helen City, the original oil plant
Vacuum deodorization
Three-stage steam jet vacuum pump instead of four steam jet vacuum pump
Zhangjiagang Zhongding Additives Co., Ltd.
Vacuum distillation
Steam series injection vacuum pump instead of water ring Roots unit
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