Tubular high efficiency heat exchanger
1、 Structural characteristics and mixing principle
The mixing process of a static mixer is carried out by a series of mixing units of different specifications installed in a hollow pipeline. Due to the role of the mixing unit, the fluid rotates left and right at times, constantly changing the flow direction, not only pushing the central liquid flow towards the periphery, but also pushing the surrounding fluid towards the center, resulting in a good radial mixing effect. At the same time, the rotation of the fluid itself also occurs at the interface of adjacent components. This perfect radial circulation mixing effect significantly reduces the temperature gradient, velocity, and mass gradient of the fluid on the pipeline cross-section, promoting the "cutting", "displacement", "rotation", "overlap" and other movements of immiscible fluids in the pipeline, thereby achieving good mixing effect.
Product model labeling
2、 Static mixer selection:
1. The selection of static mixer generally depends on the physical properties of the mixed medium used (such as viscosity, particle size, solid content, reaction speed, and working temperature and pressure). SV type is commonly used due to its good mixing performance, and is widely used in the mixing of vapor-liquid, liquid-liquid, liquid-solid and other states, such as blended oil, light oil mixing, spice emulsification, chemical reactions, etc. But the SV type system has a significant pressure drop. The SK type static mixer, due to its characteristics of low system resistance reduction and good mixing performance, is widely used in the mixing of heavy oil with water, particle size, and high solid content systems.
-Due to the different technological processes, the requirements may also vary. Therefore, in terms of selection, flexible selection should be made according to different requirements. For example, for systems with high medium viscosity, SK type is generally used; If there are certain requirements for mixing performance, the SV type can be selected and some dimensions (pipe diameter) can be appropriately enlarged.
-Of course, you can also choose through calculation.
V-type static mixer: dh=2.3 DN25 PN1.6 L=500, stainless steel flange, low-carbon steel pipeline, represented as SV-2.3/25-1.6-500C.S
Double channel H-type static mixer: dh=4.5 DN20 PN2.5 L=200, stainless steel pipeline flange, represented as SH-4.5/20-2.5-200S. S, with flange connection dimensions of PN2.5 and DN25
Pressure loss and calculation examples
For processes with high system pressure, the pressure drop generated by the static mixer is relatively small, which does not constitute a major contradiction to the process itself. For processes with low system pressure, pressure drop calculations should be conducted to meet process requirements.
The pressure loss calculation of SV, SX, and SL static mixers is based on hydraulic diameter and takes into account the effects of porosity and friction coefficient.
Reynolds number Re for SV, SX and SL ε Relationship with friction coefficient f
The pressure loss calculation of SH and SK static mixers is represented by the friction coefficient f based on the equivalent diameter and inner diameter D of the mixer:
Relation between SH, SK type Reynolds number ReD and friction coefficient f:
Example of pressure loss calculation (SV type)
The function of a distributor is to combine two or more streams of fluid into one stream, and then enter a static mixer for mixing. There are usually two types of distributors, namely the three-way pipe type and the jet type. The difference in fluid flow and pressure applicable to the three-way pipe distributor is not significant; The jet distributor is suitable for mixed media with high flow or pressure ratios.
Distributors can be made by oneself (such as the requirement for a three-way pipe type is not high), or can be commissioned for customization.
From the process flowchart, it can be seen that there must be a distributor at the front end of the static mixer. The so-called distributor is the collection, adsorption, and merging of two or more streams of fluid into one stream, which is then transmitted to a static mixer for mixing. In practical operation, the distributor equipped at the front end of the static mixer also plays a role in pre mixing and balancing the pressure difference. Therefore, the correct selection of distributors is one of the keys to ensuring the mixing effect.
1. If two equal quantities and equal pressure fluids (such as liquid liquid and vapor vapor) are mixed, the required configuration of the distributor is relatively simple. See the figure below
This is a typical distributor in the form of a three-way pipe, with all three ends using flange interfaces. A. The B end is the import of two types of materials; The C-end is the outlet and can be directly connected to the static mixer.
2. However, when mixing fluids with different quantities, pressures, or shapes (liquid vapor), it is obviously not feasible to use the aforementioned three-way pipe type distributor. For example, when the pressures of the two fluids are different and the pressure at the A end is much greater than the pressure at the B end, assuming that the pressure at the A end is equal to that at the C end, it will cause blockage or even reflux in the B end transportation. 2. When two different forms of fluids (liquid vapor) need to be mixed, it is also assumed that the A and C ends are at equal pressure, and an air lock will form at the B end. From this, it can be seen that in order to adapt to and meet the above needs, a novel distributor must be used. Jet dispenser is one of the most widely used distributors, and its working principle is shown in the following figure:
This is a schematic diagram of a jet distributor designed according to the Venturi principle. According to its principle, during the process of high-speed injection of fluid from the A end (nozzle) to sudden expansion (expansion chamber), a certain negative pressure difference (vacuum chamber) will be generated, causing the fluid at the bypass B end to be sucked in due to negative pressure.
All kinds of jet distributors currently seen in the market are designed according to this principle.
From this, it can be seen that the commonly used distributor types mainly include three way pipe type and jet type, but they can be made into different forms due to different applications and functions.
Sx mixer specifications
SV mixer specifications
SL mixer specifications
SK mixer specifications
SH mixer specifications
Listening to each customer's heart