SRDI Oil & Gas “Peton” LCC has developed a set of equipment designs with different location of the packing.
The figures below show two examples of equipment with the “Peton” packing.
- Column design with gradual reduction of the cross-section for gas passage in the packing at each upstream stage is applied during steam condensation in the column, when a steam flow sharply decreases towards the top of the column, and a liquid flow is relatively constant (fig. 1.1).
- Thus, an equal gas velocity is maintained in each section.
The geometric figure of the packing location is chosen according to the steam flow rate. It could be simple (fig.1.2) - “single-lane” and “multilane”, as well as complicated – “ring” (fig.1.1) with square and round shapes of “rings”, “chess” (fig.1.3), etc. At that, to create a small differential pressure that is important for vacuum distillation, the cross-section of steam passage in the section can be bigger than the cross-section of the column.
Selection of the figure or “ring” thickness is adjusted taking liquid load rate and gas and liquid contact time into account.
- For stripping parts of the column under conditions of light steam load and much higher liquid loads, a construction with a small cross-section of gas passage is used.
The figure of packing location can be simple “single-lane” (fig. 1.4) and complicated with a “spiral” steam circulation.
Selection of the arrangement figure is determined by steam load. By changing the cross-section of the figure such a gas velocity is achieved, at which an intense flow turbulization of liquid is provided. Gas velocity in the packing may be several times higher than for the total cross-section of the column. Cross-section for liquid passage remains close to the column cross-section.
EXAMPLE OF “PETON” PACKING MODULES COMBINATION IN COLUMN
The next example is one of variants of modules combination in the unit at designing a column for operation in a wide range of loads. Column section is formed on a three-module basis. The modules have different penetration capability in terms of gas and liquid. The figure shows the connection of two sections of the column with a three-module combination on each section. Let’s consider operation of the sections at changes of the loads in terms of liquids and steam:
- In terms of liquid
In case of design liquid loads, a contact of steam and liquid takes place in module B, where packing refluxing is performed by means of the main distributor P1.
At increasing of liquid load, P2 distributors of C module start to operate due to the fluid flowing through the draining planks. In this case, the steam contacts with liquid in B and C modules.
- In terms of steam
Steam flow passes A, B and C modules sequentially regardless of the load value.
When the load exceeds the designed value, the steam flow deflects the liquid flow in module B from its vertical direction, partly directing it to module C, where, due to another permeable capability, liquid distribution is leveled until it becomes equal throughout the packing. At very high loads the gas flow provides liquid circulation between sections. In this case, A module is involved to operation. Operation of the column approaches to loading mode. However, the principle of liquid distribution in modules is not broken at liquid circulation.