Application of double cone rotary vacuum dryer in API

Generally speaking, in API production, most of the crystallized materials need to be separated, dried and mixed This process is commonly used in API production Zui The solid phase material is separated from the suspension by filtration first, and the next process will continue to refine in the form of vacuum or heating drying The classic equipment used in this process is the double cone rotary vacuum dryer, which integrates mixing and vacuum drying, and is applied as a classic equipment by people with the characteristics of simplicity, convenience and double effects, so it is practical and economical Economically speaking, it is difficult to replace other equipment For this reason, the author reviews the structure, principle and characteristics of double cone rotary vacuum dryer, and discusses its application and common problems in API The structure principle and technological process of double cone rotary vacuum dryer the system of double cone rotary vacuum dryer consists of main machine, condenser, buffer tank, vacuum pumping system, heating system and control system As for the main engine, it is composed of rotary cylinder, vacuum pumping pipeline, left and right rotary shafts, transmission device and frame, etc The working principle of double cone rotary vacuum dryer is to introduce heat energy (such as hot water, low-pressure steam or heat transfer oil) into the closed jacket of the rotary cylinder, and the heat is transmitted to the dried material through the inner wall of the cylinder At the same time, driven by power, the rotating cylinder rotates slowly, and the materials in the cylinder mix continuously, so as to achieve the purpose of strengthening drying When working, the material is in a vacuum state The water (or solvent) on the surface of the material is saturated and evaporated through the drop of steam pressure, and is discharged and recovered in time by the vacuum pump In the drying process, the water (or solvent) inside the material continuously permeates, evaporates and discharges to the surface These three processes are continuous, and the material can achieve the drying purpose in a very short time In the process of practical application, due to the different characteristics of raw materials produced by different manufacturers, the process of double cone rotary vacuum dryer is also different At present, according to the different heating methods and solvent recovery conditions, there are two typical process flows: (1) steam heating without solvent recovery process as shown in Figure 1; (2) hot water heating and solvent recovery process as shown in Figure 2 Characteristics of double cone rotary vacuum dryer Taking the products of the company as an example, the features of the double cone rotary vacuum dryer are as follows: (1) continuous rotation of the cylinder and continuous renewal of the heating surface of the materials; (2) indirect heating, which will not be polluted, and can meet the GMP requirements; (3) high thermal efficiency, which is more than two times higher than that of the general oven; (4) stepless speed regulation or frequency conversion speed regulation of the cylinder speed according to the user's requirements; (5) constant temperature Control, temperature can be displayed by digital display; (6) it has two-stage elastic connection mode of belt and chain, so the operation is stable; (7) the specially designed tooling can ensure good concentricity of left and right rotary shafts; (8) the heating medium and vacuum system adopt reliable American technology rotary joint; (9) when it is necessary to dry viscous materials, it can also specially design the "plate reading" structure in the rotary cylinder Or set up ball; (10) heating system can have a variety of menu options, that is, the heating medium can be selected in high-temperature heat transfer oil, medium temperature steam and low-temperature hot water Application scope of biconical rotary vacuum dryer in Apis biconical rotary vacuum dryer is mainly used for drying powder, granular and fibrous materials in medicine, chemical industry, food and other industries, as well as similar biological products that need low-temperature drying It is more suitable for the drying of materials required in the following aspects: (1) materials requiring very low residual volatile content; (2) materials requiring recovery of solvents and toxic gases; (3) materials with strong irritation and toxicity; (4) materials unable to withstand high temperature heat sensitivity; (5) materials with oxidizability and danger; (6) materials requiring crystallization shape The application of double cone rotary vacuum dryer in API there are 1700 pharmaceutical joint ventures in China, among which the top 10 enterprises in the world have joint ventures in China, and the pharmaceutical industry in China has already been integrated into the ranks of international competition In recent years, chemical APIs have made great breakthroughs in technology, and the production level has been improved rapidly In the export products, chemical APIs (such as penicillin, vitamin series, iodine amine series) and some pharmaceutical intermediates account for the vast majority, and most of these drugs are dried by double cone rotary vacuum dryer The double cone rotary vacuum dryer produced by Changzhou Yibu drying equipment Co., Ltd has been successfully applied to the following materials: (1) vitamin C production of Northeast Pharmaceutical Company Vitamin C is the key product of Dongyao The 10000 ton vitamin C production line built and put into operation in 1995 is a large production line of Zui in China Eight szg-4500 double cone rotary vacuum dryers were ordered at one time At the same time, Jiangsu Jiangshan Pharmaceutical Co., Ltd has also ordered szg-5000 double cone rotary vacuum dryer for the production of vitamin series (2) artemether series production of Kunming Pharmaceutical Company Four double cone rotary vacuum dryers were ordered during the technical transformation of artemisinin API and injection workshop, which increased the capacity of artemisinin API from 1t to 2.5t 　　 (3) Zhuhai Lizhu group, in the production of national class I new drug iy-81149 and 5-amino-salicylic acid zinc API, although Lizhu group ordered a small double cone rotary vacuum dryer, its structure was special, the outsourcing and outsourcing were all domestic famous brands, and its requirements for the rotation speed deviation of the equipment, the coaxiality of the main shaft and the drum, and the temperature rise of the bearing were very high, all of which met the requirements To the international standard requirements (4) the production of chloramphenicol telmisartan, fluoxetine hydrochloride, lansoprazole and pivea of Zhejiang Essen Pharmaceutical Co., Ltd all adopt the double cone rotary vacuum dryer of the company (5) the double cone rotary vacuum dryer is also used for drying denatured starch, aspartame, D acid and other pharmaceutical intermediate materials, such as Jilin Zhenghao Modified Starch Co., Ltd., Zhejiang zhebong Pharmaceutical Co., Ltd., etc In the application of double cone rotary vacuum dryer, the common problem is that the loading capacity exceeds the theoretical capacity Because the loading capacity of the equipment is related to the bulk density of materials (referring to the mass of materials per unit volume), in general, the specific gravity of materials is calculated as 0.6g/cm3 in the design If the proportion is exceeded, the material will still be loaded according to the original theoretical amount in the actual production, which will affect the drying efficiency of the material; and the long-term operation will lead to the reduction of the service life of the motor, reducer, chain wheel and so on, until they are unable to be used In addition, some manufacturers in order to pursue production and blind operation of workers, regardless of their filling rate (the ratio of the actual loading volume to the volume of the drying cylinder), which leads to continuous problems in equipment operation and product quality of the double cone rotary vacuum dryer It is worth mentioning that the filling rate of double cone rotary vacuum dryer is usually between 30% and 50% "Vent" phenomenon In case of improper use, the double cone rotary vacuum dryer will appear in the drying process, such as vacuum tube bending, seal sleeve damage, filter head deformation and even fracture This is because in the drying process, external air (for short, venting) is put into the tank body to recoil the filter head, at this time, the tank body has reached a high vacuum, which will cause strong impact of positive and negative air flow and damage The vacuum system is broken It is worth noting that the tank body needs to be emptied after the material is dried When the tank is emptied, the flow must be controlled by the emptying valve, that is, open the valve a little at first, and then slowly increase it after the vacuum degree in the tank gradually decreases In the process of drying, there are three reasons: 1) mechanical seal leakage of vacuum end; 2) leakage or blockage of vacuum pipe; 3) filter blockage This requires inspection in the process of use, as well as maintenance, cleaning, etc It is worth mentioning that the manufacturer shall make corresponding maintenance and service terms according to different main parts in different models when preparing the use instructions, which shall be as detailed as possible For example, filter, how much time to clean, how much time to change or under what circumstances, attention points in normal use and so on Excessive noise and leakage at the inlet / outlet (1) excessive noise caused by loose foundation, damage of worm gear reducer, damage of bearing pipe, too loose or too tight broken chain, etc only regular inspection is needed to eliminate the fault in time (2) the normal leakage of the inlet and outlet is due to the damage of the sealing strip, so long as it is replaced Conclusion starting from the current situation of API production, this paper describes the principle, characteristics, typical application and common problems of the commonly used process equipment double cone rotary vacuum dryer The purpose is to improve the operation and maintenance level of users, reduce faults and operational errors, and reduce many unnecessary after-sales services of manufacturers.