AISI 304 material 0.12 mm wire size corrugated mesh packing
Hualai wire gauze structured packing is the preferred packing in distillation service for deep vacuum and low liquid rate applications. The characteristic of lowest pressure drop per theoretical stage makes wire gauze packing the preferred device for processing specialty chemicals, pharmaceuticals and temperature-sensitive materials.
Wire gauze packing is generally used in small to medium diameter columns to achieve the maximum number of theoretical stages in the minimum column height. Because of the capillary effect, the wire mesh material provides an extremely wettable surface resulting in excellent mass transfer efficiency particularly at very low liquid rates.
Hualai wire mesh structured packing products list (normal):
| Type |
Specific Surface |
Bulk Density |
Void Ratio |
obliquity |
ΔP |
Liquid spray density |
Liquid holdup |
Theo. Plate |
HETP |
F factor |
Application② |
| (m2/m3) |
(kg/m3) |
(%) |
Angle |
(Pa/plate) |
(m3/m2*h) |
% |
(piece/m) |
mm |
(m/s)*(kg/m3)0.5 |
|
| 250(AX) |
250 |
45① |
98.5 |
30 |
10-40 |
0.2-12 |
2 |
2.5-3 |
100 |
2.5-3.5 |
Precision distillation with few theoretical series |
| 500(BX) |
500 |
95① |
96.9 |
30 |
50 |
0.2-12 |
4.2 |
4-5 |
200 |
2.0-2.4 |
Vacuum Distillation of Thermosensitive and Difficult Separation Systems |
| 700(CY) |
700 |
130① |
95.6 |
45 |
67 |
0.2-12 |
6 |
8-10 |
333-400 |
1.5-2.0 |
Isotopic mixture, isomeric mixture separation |
①The data are based on 0.12mm wire, stainless steel material. Applicable temperature (-200—400)℃. 0.15mm and 0.17mm wire are also available.
②Metal wire mesh corrugated packing is suitable for clean gas-liquid system without solid particles or suspended solids or not easy to self-assemble.
Hydrodynamic performance of packed column using corrugated mesh packing
For most of the gas (vapor) liquid mass transfer processes, the gas and liquid in the packed column operate in a countercurrent manner. The conditions for determining the operating state of the packing layer are as follows:
① Gas velocity u, M / S U=
Vs volume flow of gas, m3 / S;
D -- inner diameter of tower, M.
② Liquid spray density L, m3 / (M2 · h) l=
LH -- liquid volume flow, m3 / h.
③ The geometric characteristics of the filler.
④ The physical properties of materials (gas and liquid), such as viscosity μ, surface tension σ, density ρ, etc.
The hydrodynamic properties of the packing layer mainly include pressure drop Δ P, liquid holding capacity, loading point, flooding point and effective mass transfer surface area. These parameters are related to the hydrodynamic state of packed column.
When the gas passes through the dry packing layer, the gas pressure decreases due to the resistance of the packing layer, and the pressure drop increases with the power of 1.8-2 of the gas velocity. When there is liquid spray, because the liquid is attached to the packing, there is a certain liquid holding capacity in the packing layer. With the increase of spray density, the liquid holding capacity increases, the liquid occupied space increases, and the pressure drop increases. At a certain turning point, the liquid holdup increases with the increase of spray velocity. If the gas velocity continues to increase to a certain value, the friction resistance of the gas to the liquid makes the liquid hold enough in the packing layer, so that the liquid becomes continuous phase, and the gas phase changes from continuous phase to dispersed phase and passes through the liquid by bubbling. At this time, the pressure drop increases sharply, and another turning point appears on the Δ P-U line, which is called the flooding point gas velocity, which is usually the maximum allowable in the packed tower Gas velocity.
There are three kinds of hydrodynamics in the operation of packed tower.
① Constant liquid holding state: at this time, the gas velocity is lower than the gas velocity at the carrier point, the drag force of the gas on the liquid is small, the thickness of the liquid film on the packing is basically unchanged, and the liquid holding capacity is unchanged.
② Carrier state: the gas velocity is above the carrier point and below the flooding point, the liquid film thickens and fluctuates, and the liquid holdup increases with the gas velocity. The mass transfer is in good condition.
③ Flooding state: the liquid phase turns to continuous phase, the gas is bubbling state, strong turbulence, severe backmixing in the packing layer, deterioration of mass transfer and sharp increase of pressure drop.
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