Dish contact devices of rectification and absorption apparatuses are classified:
According to the number of streams (discharges) plates are made as single-flow, two-flow and multiflow (Fig. 2.3). Also multidrain disks with evenly distributed over the area drains and disks with cascade arrangement of a cloth are used.
Multi-flow and multi-leaf trays are used in large diameter columns and at considerable fluid flow rates. Such trays provide a more uniform liquid level and vapor distribution over the contact area.
Depending on the direction of movement of vapor and liquid phase in the contact zone, there are plates with direct flow, counterflow and cross-current.
According to the organization of liquid overflow plates are divided into overflow and nonoverflow (ditch type).
According to the type of contact elements plates are divided into:
It is accepted to subdivide packed contact devices into the following two types: irregular and regular.
Counterflow plates are characterized by high liquid capacity, simple design and low metal consumption. Their main drawback is low efficiency and a narrow range of stable operation, uneven distribution of flows over the cross section of the column, which significantly limits their use.
Straight-line disks are characterized by higher productivity, but moderate separation efficiency, increased hydraulic resistance and labor intensity of manufacturing, they are preferred for application in the processes of separation under pressure.
The cross-flow plate types that have received predominant use in modern oil and gas processing technology include:
