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External circulation evaporator structure and working principle
2024 / 03 / 15
External circulation evaporator is also called external heat evaporator, its heater is directly placed on the outside of the evaporator, and the long diameter of the heating tube is relatively large, so the material liquid circulation flow rate is high. The external circulation evaporator is mainly applicable to the evaporation of the material liquid with large concentration, large viscosity and easy to be scaled and coked. This kind of evaporator in chemical industry, medicine, food and other industries have application. Due to the material liquid in the tube liquid column is higher, improve the lower part of the liquid The boiling point of the body, so the heating error is required to be larger, limiting the use of multi-effect. This evaporator raw steam (primary steam) heating temperature are higher. 1, feed: the liquid to be treated feed into the evaporator. 2, evaporation: in the external circulation evaporator, to be treated liquid from the feed pipe into a heater, and then be heated, so that part of it into a vapor state. 3.Condensation: The vapor passes through the condenser inside the evaporator, which is usually a tube bundle or heat exchanger, in which the cooling medium is transferred to condense the vapor into liquid. 4.Separation: Inside the evaporator, liquid and vapor are separated by a separation device. Commonly used separation devices include gravity separators, centrifuges and cartridges. 5.Recirculation: The separated liquid is recirculated inside the evaporator. Usually, part of the liquid will flow back to the bottom of the evaporator through a return tube to maintain the stable work of the evaporator. 6.Vapor discharge: The vapor that is not condensed is discharged from the evaporator through an exhaust port to enter the subsequent treatment or recycling. Throughout the process, the external circulation ev
Reflux methods and applications in distillation operations
2024 / 02 / 24
We know that a distillation tower generally consists of a tower kettle, tower section, condenser, discharge pipeline, output pipeline, reflux pipeline, etc. Why do we need a return line? Let's first talk about the main role of reflux in distillation towers: Firstly, provide cold reflux on the tray to remove excess heat inside the tower and maintain heat balance inside the tower; Secondly, provide a cold fluid on the tray, where the gas-liquid phases come into reverse contact. The heavy components in the upward gas condense, while the light components in the downward liquid absorb heat and vaporize. This repeated condensation and vaporization process fills the entire tower section with light components The components, the lower part is the recombinant component, further improving the separation purity of the product. Therefore, reflux liquid is a necessary condition for distillation purification. 1. Common reflux methods in distillation operations Firstly, according to the different reflux methods, it can be divided into "natural reflux" and "forced reflux". Natural reflux refers to the condenser of the tower located above the distillation tower section, with a certain height. The liquid storage outlet of the condenser is higher than the reflux outlet of the tower section and has a certain distance. The reflux liquid flows back into the tower under the action of gravity. Natural reflux operation is simple and does not require a reflux pump, saving power consumption. However, the reflux rate varies with the pressure inside the tower, and the reflux ratio is not strict. When production is abnormal, the adjustment is relatively slow. Natural reflux is widely used in small distillation units, requiring sufficient height and space. Forced reflux is the installation of a pump on the reflux pipeline, and the reflux liquid is pumped into the tower for reflux. The reflux flow rate of forced reflux is stable and easy to adjust. When p
Steps, Applications, and Efficiency Improvement Measures for Thin Film Evaporators
2024 / 01 / 24
Thin film evaporator is a type of evaporator, characterized by material flowing in a film like manner along the heating tube wall for heat transfer and evaporation. It has high heat transfer efficiency, fast evaporation speed, and short material residence time, making it suitable for the evaporation of heat sensitive substances. According to the reasons for film formation and flow direction, it can be divided into three types: rising film evaporator, falling film evaporator, and scraping film evaporator. Below are the steps, applications, and efficiency improvement measures for using thin film evaporators. Steps for using a thin film evaporator 1. Preparation before driving (1) General products have undergone water pressure testing and trial operation before leaving the factory, and the indicators meet the requirements. (2) Start the motor and observe if the direction of operation is correct. It should rotate clockwise and not reverse. (3) Measure whether the radial swing and axial string momentum of the shaft meet the requirements, and check whether the sealing is tightly sealed. (4) Whether the oil level of the gearbox is in a normal state and whether the cooling water of the mechanical seal is kept unobstructed. 2. Normal driving (1) Turn on the circulating cooling water pump and put the condenser in operation. Then open the concentrated solution container and vacuum the valve. (2) Open the feed valve and pump in the feed liquid. Connect the power, start the motor, and observe if the direction of rotation of the motor is correct. (3) Slowly open the steam valve and connect the steam trap, so that the steam pressure is around 0.15MPa. (4) Observe the discharge of the evaporator and wait for the equipment to run stably for 5 minutes before sampling and analyzing the concentration of the concentrated solution. If the concentration does not meet the standard, make adjustments. When t
The process of connecting heat exchange tubes and tube sheets in shell and tube heat exchangers
2024 / 01 / 12
Overview Heat exchangers, as heat transfer equipment that transfers part of the heat from the hot fluid between materials to the cold fluid, have a wide range of applications in people's daily lives and industries such as petroleum, chemical, power, medicine, atomic energy, and nuclear industry. It can serve as an independent device, such as a heater, condenser, cooler, etc; It can also be used as a component of certain process equipment, such as heat exchangers in some chemical equipment. Especially in the chemical industry with high energy consumption, heat exchangers are indispensable equipment in the heat exchange and transfer process of chemical production, and they also occupy a considerable proportion in the entire chemical production equipment. From the perspective of its function, heat exchangers are not only responsible for ensuring the specific temperature required by industrial processes for the medium, but also the main equipment for improving energy utilization efficiency. According to their structural forms, there are mainly plate heat exchangers, floating head heat exchangers, and fixed tube plates Type heat exchangers and U-tube heat exchangers, etc. Except for plate heat exchangers, the other types belong to shell and tube heat exchangers. Due to its large heat exchange area per unit volume, good heat exchange efficiency, and advantages such as sturdy structure, strong adaptability, and mature manufacturing process, shell and tube heat exchangers have become the most commonly used typical heat exchanger. Connection between heat exchange tubes and tube sheets in shell and tube heat exchangers In a shell and tube heat exchanger, the heat exchange tube and tube plate are the only barriers between the tube and shell sides of the heat exchanger. The connection structure and quality between the heat exchange tube and tube plate determine the quality and service life of the heat exchanger, which is
Bending and forming of tubes in pressure vessels
2023 / 12 / 18
Bending methods There are a variety of methods of pipe bending, generally manual bending and mechanical bending. Mechanical bending methods and a variety of methods, such as pressure bending method, roll bending method, back bending method and squeeze bending method. Regardless of which bending method, the main contradiction in the entire bending process are such as How to overcome the problem of local deformation. The most widely used in the project is the manual bending and bending back to the pipe bending process. Back bending method is in the rotary pipe bender bending, it can be divided into two types of mold bending and mold bending. Hand bending Manual bending does not require special equipment and complex process equipment, it can bend a variety of radii, angles and space towards the bend. But this bending mode of labor intensity, low productivity, quality is not stable enough. Manual bending of steel pipe using hot bending, for stainless steel and non-ferrous metals should be used for cold bending. Before bending in the tube first filled with filler, steel pipe filler is generally pure, dry fine sand, stainless steel and non-ferrous metal filler should be used rosin, lead and other low melting point materials Quality, in order to prevent wrinkles, and reduce the degree of ovalization Mold bending This category of pipe bender are using mold bending. The main mold has a disc-shaped grooved wheel and ram's horn core head of two kinds. Disc-shaped groove wheel bending pipe bending mold on the outside of the pipe, half of the pipe lying in the groove, the other half of the pipe bending area with a small groove roller (also known as compression roller) pressed. Roller (also known as compression rollers) pressed. Tube end is fixed by the chuck on the disc-shaped bending die, if the pressure roller does not move, disc-shaped bending die active rotation to complete the bend, known as pull bending
Method of solution crystallization, crystallizer structure, and working principle
2023 / 12 / 04
According to the different ways of solid precipitation, crystallization can be divided into various types such as solution crystallization, melt crystallization, sublimation crystallization, and precipitation crystallization. The most widely used method in industry is solution crystallization, which is achieved by cooling or removing solvents to achieve a solution that In a saturated state, precipitate solutes as products. In addition, crystallization operations can also be divided into intermittent and continuous based on whether the operation is continuous, or into stirred and non stirred based on the presence or absence of a stirring device. 1. Method of solution crystallization Solution crystallization refers to the process in which crystals precipitate from a solution. The basic condition for solution crystallization is the supersaturation of the solution, which generally goes through the following process: unsaturated solution → saturated solution → supersaturated solution → formation of crystal nuclei → crystal growth. 1. Cooling method Cooling method, also known as cooling method, is a method of achieving supersaturation of a solution by cooling down. Cooling crystallization basically does not remove the solvent, but reduces the temperature by removing the heat from the solution, allowing the solution to reach a supersaturated state and proceed with crystallization. This method Suitable for situations where solubility significantly decreases with decreasing temperature. Cooling can be divided into natural cooling, wall cooling, and direct contact cooling. The natural cooling method is to cool and crystallize a solution in the atmosphere, and its equipment structure and operation are the simplest, but the cooling rate is the same Slow, low production capacity, and difficult to control crystal quality. Wall cooling method is a widely used crystallization method in industry, which relies on indire
Thin film evaporator use steps, applications and efficiency improvement measures
2023 / 11 / 11
Thin film evaporator is a type of evaporator, which is characterized by heat transfer and evaporation of materials along the wall of the heating tube as a membrane flow, high heat transfer efficiency, fast evaporation speed, short residence time of materials, suitable for the evaporation of heat-sensitive substances. According to the reason and flow direction of the film, can be divided into three types: ascending film evaporator, descending film evaporator, scraping film evaporator. The following introduces the film evaporator use step, application, improve efficiency measures. Thin film evaporator use step 1. Prepare before driving (1) General products have been factory hydraulic test and test run, and indicators meet the requirements. (2)Turn on the motor, observe whether the running direction of the motor is correct, it should be clockwise rotation, not reverse. (3) Measure the radial swing and axial string movement of the shaft to see if it meets the requirements, and check whether the seal is sealed tightly at the sealing place. (4) Whether the oil level of the reducer is in normal state, and whether the cooling water of the mechanical seal is kept unobstructed. 2.Normal driving (1)Turn on the circulating cooling water pump, and let the condenser in operation. Then open the concentrate container and vacuum valve. (2) Open the feed valve and pump in the liquid. Turn on the power supply and start the motor, and at the same time, observe whether the rotation direction of the motor is correct. (3)Open the steam valve slowly, connect the traps, make the steam pressure about 0.15MPa. (4) Observe the discharge of the evaporator, wait until the equipment runs stably for 5 minutes, and then sample and analyze the concentration of the concentrate. Concentrate container liquid level will be full, should be switched to another easy, according to the steps for switching. 3. Normal s
Maintenance methods and quality standards for reaction kettle
2023 / 11 / 03
Kettle body 1. Replacement conditions If the reaction kettle has been used for a certain period of time and one of the following situations occurs, it should be replaced: a. The uniform corrosion of the wall thickness of the kettle exceeds the minimum value specified in the design; b. The local corrosion of the wall thickness of the kettle exceeds the minimum value specified in the design, and the corrosion area is greater than 20% of the total area; c. During the hydraulic test, there is obvious deformation or residual deformation of the equipment exceeding the specified value; d. When cracks cannot be repaired due to alkali embrittlement or severe intergranular corrosion in the reactor body or weld seam; e. When the damaged area of the porcelain surface exceeds 15% or the damaged part cannot be repaired; f. Excessive defects (such as serious structural defects that endanger safe operation, unqualified welds, severe incomplete penetration, cracks, etc.) that cannot be repaired. 2. Steel kettle body a. The partial corrosion of the shell is repaired using the arc surfacing method. If the corrosion area is large, the patching method is used for repair. b. Unpenetrating cracks. If the depth of the crack is less than 10% of the wall thickness and not more than 1mm, the crack can be ground flat with a grinding wheel and smoothly transitioned to the metal surface. If the crack depth does not exceed 40% of the wall thickness, the groove can be excavated within the crack depth range, Weld repair should be carried out, but small holes should be drilled at both ends of the crack to prevent it from extending. For long cracks, the step-by-step welding method is adopted (welding from both ends of the crack to the middle) to reduce welding stress and deformation. If the depth of the crack exceeds 40% of the wall thickness, it should be penetrated according to the Narrow crack treatm
2023 / 10 / 24
Industrial equipment to complete the absorption operation is collectively referred to as the absorption tower. Commonly, there are two kinds of plate tower, packed tower. Plate tower is mostly used for distillation operations, packed tower is mostly used for absorption operations. First, the structure of the packed tower Packed tower is mainly composed of tower, packing and its accessories (defoaming device, liquid distribution device, gas distribution device, packing support device, packing compression device, etc.). 1-foam remover; 2-liquid distributor; 3-packing limiter; 4-shell; 5-packing; 6, 8-unloading packing holes; 7-liquid re Distributor; 9-Packing support plate; 10-Overflow port Packed tower operation, the gas is fed from the bottom of the tower, distributed by the gas distribution device (small-diameter tower is generally not equipped with gas distribution device) distribution, under the action of differential pressure from the bottom upward and the liquid is countercurrent through the packing layer of the gap continuously, while the liquid from the upper part of the tower into the liquid distribution device evenly sprayed through the liquid redistributor. Into the tower, through the liquid distribution device evenly sprayed on the tower cross-section, under the action of gravity along the packing layer downward flow. On the packing surface, the gas and liquid phases are in close contact for mass and heat transfer. Packed tower belongs to continuous contact gas-liquid mass transfer equipment, packing layer gas-liquid two-phase countercurrent contact, packing wetting surface for gas-liquid two-phase contact mass transfer surface, gas-liquid two-phase composition along the tower height of the continuous change, under normal operating conditions, the gas phase is continuous phase, liquid phase is dispersed phase. Under normal operation, the gas phase is continuous and the liquid phase is dispersed.
Hydrogenation reactor working principle, role and operating procedures
2023 / 09 / 27
High-pressure hydrogenation reactor is the most important and critical equipment for many chemical industries, and whether its operation is stable and reliable seriously affects the operation of the whole production unit. In order to better use it, it is very necessary to understand the hydrogenation reactor working principle, role and procedures. Hydrogenation reactor working principle Hydrogenation reactor is a kind of pressure vessel, its working principle is to send the raw gas or hydrogen under pressure into a closed container to carry out the chemical reaction, and then discharge the reacted gas through the venting. Since the pressure of hydrogenation reactor is high (generally often more than 10mpa), it is necessary to check and maintain the equipment before use. Hydrogenation plant mainly consists of four parts: heating furnace, heat exchanger, catalyst bed and high pressure storage tank. The heating furnace consists of electric heater, steam heater and thermal oil circulation system; the heat exchanger consists of shell and tube bundle; the catalyst bed is made of stainless steel plate and carbon steel plate welded together; the storage tank consists of liquid-phase tank and gas-phase tank, in which the liquid-phase tank is used to contain the material, while the gas-phase tank is used to collect the discharged gases and sent to the purification and treatment device for further processing. When pressurized operation, first open the power switch of electric heater and the valve of cooling water to preheat the medium temperature in the jacket to reach the set value, then open the feed valve to make the material enter the reaction chamber for heating and warming to a certain temperature, then close the feed valve and open the valve of condensate slowly to prevent the pipeline from clogging due to a sudden drop in temperature or condensation phenomenon that affects the effect of heat transfer; when the needle of the pr
Layout requirements for common equipment in chemical plants (below)
2023 / 09 / 15
21 What are the specific requirements for tower side piping design? (1) tower side piping generally have reflux, feed, side line extraction, steam extraction steam, reboiler inlet and return piping, etc., in order to make the valve closed without accumulation of liquid, the valves on the above piping should be directly connected directly with the tower body orifices, inlet (outlet) feeding pipe Inlet (outlet) material piping at the same angle there are more than two inlet (outlet) material openings, the pipeline should consider a certain degree of flexibility; (2) fractional distillation tower side line to the steam tower pipeline, such as regulating valves should be installed close to the steam tower. To ensure that the regulation of the same with a section of liquid in front of the residence. The height of the liquid column should meet the requirements of the process. 22 tower bottom piping design features? (1) the bottom of the tower operating temperature is generally high, so in the arrangement of the bottom of the tower pipeline, its flexibility should meet the requirements of the relevant standards or codes. In particular, the bottom of the tower pumping pipeline and the pump is connected, the pipe should be short and less bends, and need to have enough flexibility to reduce the pump nozzle force. Less pump nozzle force. Tower bottom pumping line should be led to the tower skirt or outside the base, tower skirt is strictly prohibited to set the flange into the instrument fittings and other fittings. The bottom of the tower to the bottom of the pump pumping pipe in the horizontal pipe section shall not have a "bag shape", should be "step by step low", so as to avoid the bottom of the tower pump to produce cavitation phenomenon, the bottom of the pump. The isolation valve on the pumping pipe should be as close as possible to th
Arrangement requirements for common equipment in chemical plants (above)
2023 / 09 / 08
01 What are the types of tower arrangement? Specific requirements for? (1) single-row arrangement, generally more single-row arrangement, when there are two or more towers or vertical containers on one side of the pipeline corridor, the general centerline alignment, such as two or more towers set up a joint platform, it is appropriate to centerline alignment or tangent alignment; (2) multi-row arrangement, for the smaller diameter body higher tower, can be arranged in double rows or into a triangle arrangement, so that the platform can be used to link the tower together to improve its stability. However, the platform rooted members should be used to guide nodes that can slide to adapt to the thermal expansion effects of different operating temperatures; (3) frame type arrangement, for the diameter DN ≤ 1000mm tower can also be arranged in the frame or the side of the frame. The frame is used to improve its stability and set up platforms and ladders. For the segmented tower arranged on the frame, when it is not possible to use motorized lifting gear, it should be set up on the frame for maintenance and lifting facilities. 02 What are the requirements for the arrangement of the tower and its associated equipment? The tower and its associated equipment such as feed heater, non-flame heated reboiler, condensation cooler at the top of the tower, reflux tanks, pumping pumps at the bottom of the tower, etc., it is desirable to be arranged close to the order of the process, and if necessary, can be formed into an independent operating system located in a zone, so as to facilitate the operation and management. 03 along the pipeline corridor arrangement of the tower and vertical pipe apparatus and how to determine the spacing of the pipeline corridor? (1) When arranging the pumps between the tower and the pipe corridor, it should be determined according to the operation, maintenance and piping requirements of the pump
How do I select a heat exchanger?
2023 / 08 / 31
Heat exchanger can be broadly divided into shell and tube heat exchanger and plate heat exchanger and so on according to the structure. Among them, the shell and tube type has a long history, is the most widely used type of heat exchanger, has the advantages of easy manufacturing, low production cost, wide range of materials, easy to clean, adaptable, large capacity, reliable, adaptable to high temperature and high pressure. I. Fixed tube and plate heat exchanger Fixed tube and plate heat exchanger tube plate at both ends, the use of welding methods and shell connection fixed Advantages: 1. simple and compact structure, in the same shell diameter, the largest number of rows of tubes, the minimum bypass. 2. each heat exchanger tube can be replaced, and easy to clean the tube. 3. Compared with other shell and tube heat exchangers, the tube plate is the thinnest, low cost. Disadvantages. 1. Shell process cannot be mechanically cleaned; 2. when the temperature difference between the heat exchanger tube and the shell is large (greater than 50 ℃) when the temperature stress, the need to set up expansion joints in the shell, and thus the shell pressure by the expansion joints can not be too high strength limitations. Fixed tube and plate heat exchanger for the shell side of the fluid is clean and not easy to scale, the temperature difference between the two fluids is not large or large temperature difference but the shell pressure is not high occasions. Because of such heat exchangers have concentrated the advantages of shell and tube heat exchanger, so it is widely used. II. Floating head type heat exchanger Floating head type heat exchanger for fixed tube and plate heat exchanger defects in the structure of the improvement, the two ends of the tube plate only one end of the tube plate and shell fixed, while the other end of the tube plate can move freely in the shell, the end is
Distillation unit - Plate column structure and principle
2023 / 08 / 17
A distillation column is a tower-type vapor-liquid contact device for distillation. As the main equipment of the distillation process, there are two main types of plate columns and packed columns. According to the operation mode can be divided into continuous distillation column and batch distillation column. Today we will take you to understand the structure and principle of plate column. Plate column Plate towers are usually composed of a cylindrical shell and a number of plates (or plates) set horizontally along the tower height at a certain spacing. Plate tower plate The plates of a plate tower can be divided into two categories: those with drop tubes and those without drop tubes. In general, the liquid with a drop tube is staggered flow, and the liquid without a drop tube is counterflow. Plate tower can be divided into bubble tower, floating valve tower, sieve plate tower, tongue and slant plate and so on. Among them, the bubble tower, floating valve tower and sieve plate tower are the most widely used in industrial production. 1 Blister tower Blister tower plate is the earliest industrial application of the tower plate, it is composed of gas pipe and bubble. Blister is installed on the top of the ascending tube, divided into two kinds of round and strip, the former is more widely used. There are three sizes of blister, f80, f100 and f150mm, which can be selected according to the size of the tower. The lower periphery of the bubblers has a lot of teeth slits, which are generally triangular, rectangular or trapezoidal. Blisters are arranged in triangular shape on the tower plate. The edge of the blister is equipped with longitudinal tooth slits, and the center is equipped with a gas lift tube. The rising gas pipe is directly connected to the tower plate. The gas phase under the tower plate enters into the rising tube, and then blows out from the teeth to contact with the liquid phase on the tower pl
The most complete knowledge of chemical separation technology, do you know it all?
2023 / 08 / 11
Chemical separation technology is an important branch of chemical engineering, whether it is petroleum refining, plastics chemical fiber, hydrometallurgy, isotope separation, or the refining of biological products, the preparation of nano-materials, desulfurization of flue gas and fertilizer pesticide production, and so on can not be separated from the chemical separation technology. Chemical production of raw materials and products in the vast majority of mixtures, the need to use the system of differences in the physical properties of the components or with the help of the separator to make the mixture to be separated and purified. It is often a key step to obtain qualified products, fully utilize resources and control environmental pollution. Along with the rapid development of the chemical industry, separation technology has also gained high speed development. On the one hand, the research and application of traditional separation technology has been progressing continuously, the separation efficiency has been improved, the processing capacity has been increased, the engineering enlargement problem has been solved gradually, and new separation devices have been appearing continuously; on the other hand, in order to adapt to the technological progress and put forward new separation requirements, the development, research and application of membrane separation technology, supercritical extraction technology, adsorption technology and other existing separation technologies have become the frontiers of the separation engineering research. The topic. The importance of chemical separation process Chemical separation process is the operation of separating a mixture into two (or several) products of different compositions. A standard chemical production plant consists of a reactor and a number of separators for the purification of raw materials, intermediates and products. Firstly, the separation process su
What type of heat exchanger is a reboiler?
2023 / 07 / 27
First, the principle and role of reboiler Reboiler is a heat exchanger that can reboil the fluid in the heat exchange process. Its main principle is to flow in the heat exchanger through the pipeline inside the low-pressure steam or other liquids, in the process of heating to produce a one-time boiling, and then in the process of continuing to heat the process of reboiling, thereby improving the efficiency of heat transfer. Reboiler is mainly used in chemical, petroleum, food, pharmaceutical and other industries, in the steam generator, air conditioning systems, distillation equipment and other fields play an important role. Among them, it is most widely used in the evaporator, which can greatly improve the heat exchange efficiency and also save energy consumption. In addition, the reboiler can also be used to heat low-quality fluids, such as oil, water, sewage and chemicals. Second, the advantages and disadvantages of reboiler Compared with other types of heat exchangers, reboiler has the following advantages: 1. energy efficient: reboiler can be released in the heat transfer process to make full use of latent heat, improve the efficiency of heat transfer, but also to save energy consumption. 2. High-speed heat transfer: In the process of heat transfer in the reboiler, due to the one-time boiling and reboiling, so the heat will be transferred quickly, so that high-speed heat transfer can be carried out. 3. Wide range of applications: reboilers are widely used in many industries, such as chemical, petroleum, pharmaceuticals and so on. However, the reboiler also has certain disadvantages: 1. easy to produce oscillation: due to the presence of a large number of bubbles in the reboiler fluid, so in the process of heat transfer is prone to oscillation, thus causing some damage to the equipment. 2. susceptible to scaling and corrosion: in
Those secrets in the design of steam piping for chemical plants!
2023 / 07 / 20
When designing steam piping in a chemical plant, in order to ensure the quality and efficiency of the design, the pipe diameter should also be reasonably selected, and the piping should be arranged to meet the requirements of the stress, in addition to paying attention to a number of other details to avoid the phenomenon of water hammer. 01 Design of steam piping Many different pipelines are set up in the chemical plant, generally arranged outside the plant or along the plant, supported in the air with a bracket, becoming a pipe corridor. There are specific requirements for the configuration of the pipe corridor, generally the process material pipes are arranged in the first layer and the first layer of the corridor, the utility piping is arranged in the third layer, and the instrumentation cable trough plate is arranged in the fourth layer. Among them, the steam pipes are arranged in the third layer. In order to facilitate the setting of π-shaped compensator, generally the steam pipeline should be arranged on the side of the corridor. At high temperatures, the steam pipes will expand, and the π-compensator can be used to absorb the thermal expansion of the pipes. Because bellows expansion joints are more expensive and do not have a long service life, they are generally not used to absorb the thermal expansion of steam pipes. When determining the installation position of the compensator, the pipeline should first be analysed strictly so that the compensator can be set centrally. The pipelines with high temperature and large compensation capacity are usually set up on the outside, while the pipelines with low temperature and small compensation capacity are set up on the inside. pi-shaped compensators are usually set up in the middle, and guiding frames are set up on both sides of the compensators to determine the distance between the guiding frames and the compensators according to the stress of the pipelines. When calculating t
Working principle, internal structure, and pH value of acid mist absorption tower
2023 / 07 / 06
Acid mist purification tower, also known as: acid gas purification tower, acid mist purification tower, acid mist absorption tower, waste gas purification tower, and fiberglass acid mist purification tower. As an important waste gas treatment equipment, acid mist purification tower is already essential in industrial production. The following introduces the basic knowledge of acid mist absorption tower, mainly including its working principle, structural composition, and pH value. Working principle of acid mist absorption tower The acid mist absorption tower uses sodium hydroxide alkali solution to neutralize the hydrochloric acid mist. After the gas outside the tower body enters the tower body, it enters the packing layer through the perforated plate. There is spray liquid (sodium hydroxide solution) from the nozzle distribution on the packing layer, and a layer of liquid film is formed on the packing. When the gas flows through the packing gap, it contacts with the packing liquid film for absorption or neutralization reaction, and the gas continues to walk upward, After several absorption or neutralization, the gas is collected by the mist eliminator and discharged outside the tower through the air outlet. After treatment, the discharge amount of hydrochloric acid mist is 0.0069t/a (0.00144kg/h), and the emission concentration is 0.288mg/m3, which can meet the secondary standard in the "Comprehensive Emission Standard for Air Pollutants" (GB16297-1996). The measures taken are reasonable and feasible. Workflow: 1. After being compressed, the raw gas enters the condenser for cooling to around 50 ° C, and then enters the absorption tower for spray washing; 2. The washed gas passes through a degreasing filter to remove oil and impurities; 3. Then, after being pressurized by a fan, it is sent to a dryer for heating and dehydration to form dry gas (at a temperature of 100 ° C), and then sent to an absorbent storage tank
Heat exchanger basics, read and think more
2023 / 06 / 30
A, two media string each other (internal leakage) 1 Generate causes ① heat exchanger tube corrosion perforation, cracking. ② heat exchanger tube and tube plate expansion mouth (weld mouth) cracked. ③ floating head type heat exchanger floating head flange seal leakage. 2 processing methods ① replace or plug the leaky heat exchanger tube. ② heat exchanger tube and tube plate re-expansion (welding) or plugging. ③ tighten the bolts or replace the sealing gasket. Second, the flange at the seal leakage 1 Cause ① gasket under pressure, corrosion, deterioration. ② Insufficient bolt strength, loosening or corrosion. ③ flange rigidity and sealing surface defects. ④ flange is not flat or misaligned, gasket quality is not good. 2 Processing method ①Tighten the bolts and replace the gaskets. ②Upgrade the bolt material, tighten the bolt or replace the bolt. ③Replace the flange or deal with the defect. ④Reassemble or replace the flange and replace the gasket. Poor heat transfer 1 Causes ①Heat exchange tube scaling. ②Bad water quality, oil and microorganisms. ③Separator short circuit 2 Treatment method ①Chemical cleaning or jet cleaning of dirt and grime. ②Strengthen filtration, purify media and strengthen water quality management. ③Replace the tube box gasket or replace the bulkhead. Fourth, the resistance drop exceeds the allowable value 1 Cause Scaling inside the shell, inside and outside the tube 2 Treatment method Use jet or chemical cleaning scale V. Serious vibration 1 Generated by ① Resonance caused by the frequency of the medium. ② Resonance caused by external pipe vibration. 2 Treatment method ①Change th
The most common distillation column anomalies and incorrect operation!
2023 / 06 / 21
In chemical plant production, the distillation tower is the most common and typical separation equipment, any person engaged in chemical production will not be unfamiliar with the distillation tower, but the common outstanding problems in the operation of the distillation tower, such as: liquid flooding, flooding tower, flushing tower phenomenon, the reasons are not very clear, the problem occurs when the response to the tower parameters changes are not sensitive, so often delay the solution to the problem, affecting the production of the device. A detailed analysis of the causes of the above mentioned problems, plus examples to show the parameter changes and incorrect operation when problems occur in production! Firstly, let's look at the most familiar phenomenon of liquid flooding ► What is liquid flooding? In a distillation column, the accumulation of liquid phase beyond the space in which it is located for various reasons is called liquid flooding. Liquid flooding can be divided into liquid flooding of the drop tube, liquid flooding of the mist entrainment, etc. Liquid flooding refers to the accumulation of liquid phase in the descending tube to the last layer of the tower plate. Mist entrainment liquid flooding refers to the open space on the tower plate of the gas phase flow rate reaches a certain speed, so that the liquid phase on the tower plate along with the rising gas phase into the upper layer of the tower plate. The operating condition when liquid flooding occurs is called the liquid flooding point. When designing a distillation tower, the liquid flooding rate must be maintained within a certain range to ensure the stable operation of the distillation tower. When liquid flooding begins, the pressure drop of the column rises sharply and the efficiency drops dramatically. Subsequently, the operation of the column is disrupted. ► What causes the liquid flooding phenomenon? 1. Liqui
Operation and maintenance of plate towers
2023 / 06 / 09
1. plate tower equipment before driving preparation General tower equipment in the overhaul or re-drive before the following work should be done: ① carefully check whether the water, electricity, steam can guarantee normal production needs. ② various material conveying devices such as pumps, compressors and other equipment can be normal operation. ③ equipment, instrumentation, fire safety facilities are complete and complete, there are computerized automatic control devices should be tested to adjust the system. ④ All valves should be in normal operation in the open and closed state, and to ensure that there can be no leakage, escape steam running liquid phenomenon. ⑤ each condensing, cooler beforehand to test whether leakage, arrange to send water pre-cooling, the whole tower equipment to send steam first warm tower. (6) before and after the unblocking section contact, grasp the feed concentration and storage tank tank liquid volume, notify the laboratory for sample analysis preparation work. 2. Typical plate tower equipment operating requirements As the plate tower equipment in the chemical production of a wide range of applications, can not be described one by one its operation process, here only in the petroleum refining common normal reduced pressure distillation device distillation tower as an example to introduce its operating procedures: ① check the distillation tower system valve: ① Check the distillation tower system valve off / on whether the correct. Before distillation begins, open the cooling water circulation system, and open the pressure relief valve, then open the condenser cooling water valve, adjust the water pressure to 0.15MPa, close the feed rotor flow meter valve. ② Turn on the distillation tower system vacuum, vacuum degree according to specific process req
Principle of distribution of flow paths in heat exchangers
2023 / 06 / 01
Allocation principles In shell and tube heat exchangers with no phase change fluid transfer, the cold and hot fluid flow paths can be selected according to the following principles. 01 Unclean or easily decomposed scaling materials should flow through the side that is easy to clean. For straight tube bundles, it is generally advisable to go inside the tube so that the fluid velocity can be easily controlled, while the higher fluid flow rate allowed inside the tube also reduces scaling; when the tube bundle can be removed for cleaning, it can also go outside the tube. 02 Corrosive fluids should be taken inside the tube to avoid corrosion of the tube bundle and the shell at the same time. 03 Very high temperature (or very low) materials should go inside the tube to reduce the loss of heat (or cold), but also to reduce the need for special metals, reducing the cost of heat exchangers; but the fluid required to be cooled should go to the shell process, to facilitate heat dissipation. 04 High pressure materials should go to the tube process, so as to avoid shell pressure, thus reducing costs. 05 Allow the pressure drop is very low fluid should take the tube process, the pressure drop is the same, the tube process can get a higher heat transfer coefficient. 06 Steam should go to the shell process, because it is relatively clean, the heat transfer coefficient and the flow rate is small and easy to discharge condensate. 07 Fluids with high viscosity are generally suitable for the shell process, where turbulence can be achieved at lower flow rates. If turbulence cannot be achieved in the shell process, then the tube process is preferred and the calculated heat transfer coefficient for the tube process is more accurate. 08 Fluids with low flow rates are preferred to go through the shell process, where turbulence can be achieved at lower flow r
Introduction to the classification of tower equipment
2023 / 05 / 26
With the continuous development of chemical production processes, tower equipment has also developed a wide range of structures and types in order to meet various process requirements. In order to facilitate research and comparison, the tower equipment is classified from different perspectives. For example: by operating pressure into pressurised towers, atmospheric towers and reduced pressure towers; distillation towers, absorption towers, desorption towers, extraction towers, reaction towers and drying towers by unit operation; According to the formation of inter-phase contact interface is divided into the way with a fixed phase interface and the flow process to form the phase interface of the tower and so on, the following is the conventional classification of several tower equipment. 1. According to the use of classification (1) distillation tower The use of liquid mixtures in each component of the volatility of the difference to separate its various liquid components of the operation known as distillation, repeated multiple distillation process known as distillation, to achieve the distillation operation of the tower equipment known as distillation tower. Such as normal decompression device in the atmospheric pressure tower, decompression tower, crude oil can be separated into gasoline, paraffin, diesel and lubricants, etc.; platinum reforming device in a variety of distillation tower, can be separated out of benzene, toluene, xylene, etc.. (2) Absorption towers, desorption towers The process of separating gases by absorbing liquid using the different solubilities of the components in the solution is called absorption; the process of releasing the dissolved gases from the absorbing liquid by heating is called desorptio
How are the process parameters of a distillation column adjusted and what factors influence them?
2023 / 05 / 08
In the pharmaceutical, petrochemical, fine chemical and other fields, there are often many liquid-phase mixtures that need to be separated or purified, and distillation technology has become the most widely used and largest mass transfer separation process. 1. How to adjust the pressure of the tower in distillation operation? What are the factors affecting the variation of tower pressure? The tower pressure is one of the main control indicators of the distillation tower. For any distillation tower operation, the tower pressure should be controlled within the specified index to adjust other parameters accordingly. Tower pressure fluctuations are too large, it will destroy the material balance and gas-liquid balance of the tower, so that the product does not meet the required quality. Therefore, many distillation towers have their specific measures to ensure that the tower pressure is stable within the appropriate range. For the tower pressure of the pressurised tower, there are two main methods of adjustment. ① tower condenser for the top of the condenser, tower pressure is generally dependent on the amount of gas phase extraction to regulate. In the case of other conditions remain unchanged, the gas phase extraction volume increases, the tower pressure decreases; the gas phase extraction volume decreases, the tower pressure increases. ② tower top condenser for the full condenser, tower pressure is mostly dependent on the size of the cold dose to adjust, that is, equivalent to adjust the temperature of the reflux liquid. Under the premise of other conditions remain unchanged, increase the cold dose, the temperature of the reflux liquid is reduced, the tower pressure is reduced; if the cold dose is reduced, the temperature of the reflux liquid rises, the tower pressure rises. For the pressure control of the reduced pressure distillation tower, there are two main methods. ①Wh
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