Figure 78 shows the outline of the absorption process in which the gas is in contact with a countercurrent in light oil through an absorber tower. The contact in the tower can be through food or packaging. The gas entering the cold tower to report an improved removal of the components of interest. The oil used to make the removal of the tower comes from the top and is known as oil-poor, out of the tower, on the bottom carries the components removed and the gas is known as a rich oil. The gas leaving the absorber tower is basically methane and is known as residual gas. The rich oil that comes from the absorber passes a column stabilization in this case, releasing the oil-rich ethane and methane, which was unable to leave the absorber, in this case is not seeking ethane. When ethane is needed, the oil becomes a rich desmetanizadora and the fluid that comes out of it goes to a desetanizadora. Reflux in desentanizadora is to improve the separation of methane and ethane.
Table 26 -. Specifications of liquefied petroleum gas (1)
PRODUCT
Feature. Product.
Commercial propane. Commercial butane. P-B Commercial mixtures. Propane
HD-5 Test Methods
Basic composition and propane or butane and propylene Basically / butylene or mixtures of commercial propane and butane 90 propane liquid omas and 5 or less of liquid propylene ASTM D-2163-82
Vapor pressure at 100 F, LPCM., Max 208 70 208 208 ASTM D-1267-84
Resid Vol Evap.del temp. For reliable service and competitive rates try using – there is no sales tax to pay. 95 F, Max, V, max, V, Max
-37
2.5 —
36
—
2.0
36
—
2.0
-37
2.5
—
ASTM D-1837-81 ASTM D-2163-82 ASTM D 2163-82 Mat Res. Org.: Res to Evap.100 ml.
0.05 ml – – 0.05ml Composition ASTM D-2158-80 Copper Corr. Lam, Max. No. 1 No. 1 No. 1 No. 1 ASTM D-1838-84 S, Total, ppmw 185 140 140 123 ASTM D-2784-80 Cont nothing nothing water – —
The liquid that comes out of going to another column desetanizadora stabilizing known as fractions, in which propane, butane and heavier components removed for gas in the absorber is separated from the oil absorption and vapor emerging as the top of the column, and the liquid, which is basically the poor oil comes from the bottom and is recycled to the absorber to continue the process.
Gases leaving the fraction is condensed and part of this condensate is used as reflux to improve the efficiency of the fractionator and the rest go to product storage, in case you do not want to make separation of LPG and natural gasoline, fractionation or otherwise.
Both the desetanizadora as in the fractionator are warming at the bottom to improve the process of stabilization or removal of ethane and methane in the first and the propane and heavier components in the second. The warming in the bottom of the fraction shall be such that the temperature there is close to boiling point of oil-poor, to ensure a total removal of propane and heavier components which removed the oil and gas well that the oil is pure poor recirculates to the absorber tower.
Figure 78 -. Diagram of the Gas Processing absorption.
This treatment plants for absorption, are not widely used because they are difficult to operate and monitor their effectiveness poor oil well is contaminated and loses its efficiency to remove the intermediate hydrocarbons from natural gas. Typical recoveries in this type of plant are C3 ’80 C4′ 90 , C5 ’98 .