、螺杆真空泵在制药行业溶媒回收中的应用 1. Application of screw vacuum pump in solvent recovery of pharmaceutical industry
After the crystallization of the drug substance in the solvent crystallization process, it is filtered, washed, and dried under vacuum. ％左右，加热温度不能超过80 ℃，干燥后原料药含湿量要低于0.5 ％，为了抽除物料中溶媒，干燥罐内的压力要低于干燥温度下溶媒的饱和蒸汽压，通常要求在中真空压力0.1Pa- 50Pa条件下干燥。 The moisture content of the material is generally about 20 %, and the heating temperature cannot exceed 80 ° C. After drying, the moisture content of the drug substance should be less than 0.5 %. In order to remove the solvent from the material, the pressure in the drying tank should be lower than that of the solvent at the drying temperature. Saturated vapor pressure is usually required to be dried under a medium vacuum pressure of 0.1Pa-50 Pa . The solvents carried by wet materials are usually flammable, explosive, toxic, and hazardous hazardous chemicals, which are pumped away by the vacuum unit during the drying process. Roots liquid ring vacuum pump systems are commonly used in traditional wet vacuum systems. The sealing liquid of the liquid ring pump will dissolve or absorb part of the organic solvent during operation and be separated into exhaust gas and high-concentration organic waste liquid in the vapor-liquid separation tank. Both parts need to be processed, which not only cannot fully recover this part of the solvent, but also increases the operating costs of the enterprise, and also brings harm to health, safety and environmental protection. The use of a dry vacuum system composed of a roots pump and a screw vacuum pump can make The organic solvent in the drying process condenses on the exhaust side to realize the recovery of the solvent. Because there is no other process medium in the screw pump pump cavity, it is energy-saving and environmentally friendly, and there is no problem of waste liquid treatment. The solvent can be fully recovered. Therefore, screw vacuum pumps have become the best choice for this application area. 所示。 Its dry vacuum pump system is shown in Figure 9 .
The solution is as follows:
Purge and seal (gas barrier)
非驱动端的后盖与泵腔之间，用氮气或氩气等惰性气体吹洗的方法来产生一个压力差即所谓气障，从而确保前盖处的润滑油和后盖处的润滑脂不受工艺气体的污染，所以在化工、制药这一类行业应用中，密封吹洗是不可缺少的一项重要措施。 Purging at the seal: The purpose is to purge between the front cover of the driving end / rear cover of the non-driving end and the pump cavity with an inert gas such as nitrogen or argon to generate a pressure difference, called a gas barrier, to ensure the front The lubricating oil at the cover and the grease at the rear cover are not contaminated by process gases. Therefore, in the applications of chemical industry and pharmaceutical industry, seal purge is an indispensable measure. 、图11所示。 The driving and non-driving end seal purge parts are shown in Figures 10 and 11, respectively.
； ★ Sealed purge pressure: maximum 0.5kg / cm 2 g ;
分； ★ Flow: Liters / min;
In general, it is not recommended to perform seal purge at the non-drive end, because purging at the non-drive end seal will reduce the effective pumping speed of the pump and affect the ultimate vacuum of the pump.
停机（清洗）吹洗 On / off (washing) purge
停机（清洗）吹洗：其目的是为了在泵运行前使泵腔内温度升高，防止工艺气体在泵内凝结以及在泵运行后通过吹洗来清除泵内的残留工艺气体，这种吹洗是在主阀关闭情况下，从泵口通入氩气、氮气等惰性气体，并使泵连续运行20~30分钟，这种开机/停机（清洗）吹洗在抽除腐蚀性气体、有毒气体或聚合物时显得特别重要。 Start-up / stop (clean) purge: The purpose is to increase the temperature in the pump cavity before the pump is running, to prevent the process gas from condensing in the pump, and to purge the remaining process gas in the pump after the pump is running. This type of purging is to pass inert gas such as argon, nitrogen and so on from the pump port when the main valve is closed, and make the pump run continuously for 20 ~ 30 minutes. This kind of startup / stop (cleaning) purging is used to remove corrosive gas. It is especially important when toxic gases or polymers.
； ★ Purge gas pressure: maximum 1.5kg / cm 2 g ;
分； ★ Flow: Liters / min;
停机（清洗）吹洗，泵内的残余物质仍然无法清除掉，而且都堆积在泵内，那么就会导致泵在重新启动时电机过载或损坏螺杆和泵体。 If the screw vacuum pump is blown through the above start / stop (cleaning), the residual material in the pump still cannot be removed, and it is accumulated in the pump, then it will cause the motor to overload or damage the screw and pump body when the pump restarts. Steam flushing is one of the methods to remove residual process material in the pump.
； ★ Steam pressure: 1kg / cm 2 g ;
★ System isolation: When steam flushing, cut off the pump power and all control circuits, close the inlet valve, and open the drain valve of the muffler;
～ 20分钟； ★ Inject steam into the air inlet of the pump for 10-20 minutes;
★ Rotate the pump shaft by hand to check whether the pump rotates smoothly;
★ If the pump rotates smoothly, stop injecting steam;
★ Turn on the motor and check if the pump is running normally;
、 螺杆真空泵在石化行业汽油蒸汽回收方面的应用 2. Application of screw vacuum pump in gasoline vapor recovery in petrochemical industry
，油气处理效率﹥ 95%的标准。 With China's increasing emphasis on environmental protection, the country or industry has formulated various laws, standards and regulations to strictly restrict the emission of gasoline vapor. It is required to add oil and gas recovery devices to oil storages, gas stations, etc., and meet the emission concentration ﹤ 25g / m 3 , oil and gas treatment efficiency ﹥ 95% standard.
The oil and gas recovery device uses active adsorption to separate hydrocarbon components from air in oil and gas to meet emission standards, and the regeneration of activated carbon is achieved by vacuum desorption to achieve the purpose of recycling. Vacuum desorbed oil and gas is converted into gasoline and recovered by gasoline spray absorption.
、 C5 、 C6等汽油蒸汽，其装置原理如图12所示。 The dry screw vacuum pump is a key device in the gasoline vapor recovery device. The pumped gas is volatile gasoline vapor. The main component is C4 , C5 , C6 and other gasoline vapors. The principle of the device is shown in Figure 12 .
℃以下，另外在多数现场都不能提供冷却水，可以提供的冷却液就是汽油；为了降低泵的运行温度，对于抽速为800m 3 /h以上的大型泵，除了泵体夹套通入汽油外，最有效的方法就是向泵腔内（在温度最高点）注入适量的汽油，通过汽油蒸发吸热来降低泵腔内温度，如图13所示。 In consideration of safety, gasoline recovery usually requires the pump's operating temperature to be controlled below 80 ° C. In addition, cooling water cannot be provided at most sites. The cooling fluid that can be provided is gasoline; in order to reduce the operating temperature of the pump, the pumping speed is 800m 3 / For large pumps above h , in addition to pumping gasoline into the jacket of the pump body, the most effective method is to inject an appropriate amount of gasoline into the pump cavity (at the highest temperature), and reduce the temperature in the pump cavity by absorbing heat from the vaporization of the gasoline, as shown in the figure. 13 shown. Its gasoline injection volume is as follows:
As the screw vacuum pump is in the process of oil vapor recovery, the condensed gasoline will accumulate at the exhaust port of the pump. If it is not discharged in time, it will cause abnormal vibration and noise of the pump. Therefore, the following two improvement measures can be taken.
：泵的排气管向下倾斜，排气管道位置要低于泵的排气口位置（见图14 ） Measure 1 : The exhaust pipe of the pump is inclined downward, and the position of the exhaust pipe is lower than the position of the exhaust port of the pump (see Figure 14 )
：在泵的排气口或消音器最低位处安装一台循环泵，以消除排气口的积液现象。 Measure 2 : Install a circulating pump at the exhaust port of the pump or the lowest position of the muffler to eliminate the accumulation of liquid at the exhaust port. ） (See Figure 15 )
、螺杆真空泵在航空、航天空间模拟方面的应用 3. Application of screw vacuum pump in aviation and aerospace simulation
到几个Pa ，而且被抽气体中含有大量的水蒸气或部分氮氧化物，所以这种真空系统首先遇到问题就是预抽真空问题，如果选用传统的滑阀真空泵作前级泵则存在下列问题： Because the volume of the pumped container of the space simulation device ranges from several thousand cubic meters to tens of thousands of cubic meters, the pressure varies from tens of thousands Pa to several Pa , and the pumped gas contains a large amount of water vapor or some nitrogen oxides, so this The first problem encountered in this type of vacuum system is the problem of pre-evacuation. If a traditional sliding valve vacuum pump is used as the foreline pump, the following problems exist:
★ First, the spool valve pump runs for a long time under high inlet pressure. Due to the air flow carrying effect, the fuel injection phenomenon is very serious. One is to waste a lot of expensive oil, and the other is to pollute the environment.
★ Because the gas to be pumped contains a large amount of water vapor or nitrogen oxides, once these gases enter the pump, the vacuum pump oil will rapidly emulsify and deteriorate, and the tightness of the oil will be damaged, resulting in a decrease in vacuum performance and even damage to the pump;
★ The number of pumps to be configured is large, and the vibration and noise of the slide valve pump are also large;
Screw vacuum pumps have become the first choice for large-scale space simulation vacuum systems due to their advantages such as clean and oil-free, high pumping speed, low vibration and low noise. In addition, in order to increase the pumping speed and ultimate vacuum of the vacuum unit, and at the same time reduce the size of the screw pump, a two-stage unit consisting of a roots pump and a screw vacuum pump in series or two roots pumps and A three-stage unit consisting of a screw vacuum pump in series. 。 In order to prevent particulate impurities from entering the pump, inlet filters are equipped at the inlet of the vacuum unit with an accuracy of 50um .
为某空间模拟装置真空系统单套真空泵机组照片。 FIG. 16 is a photo of a single vacuum pump unit of a vacuum system of a certain space simulation device. 带旁通阀罗茨泵（抽速1200L/S ），前级泵为SP1500螺杆真空泵（抽速1300m 3 /h （ 50Hz ））， 单套机组抽速为1200L/s ，极限压力10 -1 Pa 。 The main pump is ZJB-1200 roots pump with bypass valve (pumping speed 1200L / S ), the foreline pump is SP1500 screw vacuum pump (pumping speed 1300m 3 / h ( 50Hz )), and the pumping speed of a single set is 1200L / s . The ultimate pressure is 10 -1 Pa .
为某空间模拟装置真空系统单套真空泵机组照片。 FIG. 17 is a photo of a single vacuum pump unit of a vacuum system of a certain space simulation device. 罗茨泵（五点机械密封，抽速5500m 3 /h ），中间泵为RP2000罗茨泵（五点机械密封，抽速2400m 3 /h ），前级泵为SP1500螺杆真空泵（抽速1300m 3 /h （ 50Hz ）），单套机组抽速为1500L/s ，极限压力10 -2 Pa 。 The main pump is RP3600 roots pump (five-point mechanical seal, pumping speed 5500m 3 / h ), the intermediate pump is RP2000 roots pump (five-point mechanical seal, pumping speed 2400m 3 / h ), and the foreline pump is SP1500 screw vacuum pump ( The pumping speed is 1300m 3 / h ( 50Hz )), the pumping speed of a single unit is 1500L / s , and the ultimate pressure is 10 -2 Pa .
The vacuum pump system is a hot spot in the current vacuum industry, but it is still in its infancy in China, so there are some problems in design, manufacturing and operation. The author believes that in order to further promote the application of screw vacuum pumps, the following points must be achieved:
）首先是螺杆真空泵系统必须是性能稳定、运行可靠。 ( 1 ) First, the screw vacuum pump system must be stable in performance and reliable in operation.
）制造厂商要根据用户的不同工艺，提出不同的解决方案。 ( 2 ) Manufacturers should propose different solutions according to different processes of users.
）做好售前培训和售后服务。 ( 3 ) Pre-sales training and after-sales service.
）操作者要根据使用手册规定的要求，做好日常维护和保养。 ( 4 ) The operator should do daily maintenance and maintenance according to the requirements specified in the manual.