SU232425A1 - METHOD FOR OBTAINING STABILIZED GAS GASOLINE FROM NATURAL AND ASSOCIATED GASES - Google Patents

Description

The invention relates to the field of extraction of normal and isohydrocarbons of methane from natural gases and natural gas production, in particular to extracting processes and these gases using solid sorbents.

Coal adsorption method for stripping natural and associated gases is well known and widely used in industry. It consists in passing natural (passing) gas through a layer of activated carbon, as a rule, before the appearance of butane by layer.

The absorbed hydrocarbons are desorbed, ruted with water-steam. Then the layer is dried with hot air, cooled, and the cycle is repeated anew. The mixture of water vapor and hydrocarbons separated during the desorption stage is condensed, and the condensate is separated in a three phase separator. The upper liquid separator layer is unstable gasoline. To use the resulting product as a motor fuel, it must be stabilized. According to a known method, this operation is carried out in a separate distillation column. The head flow of the rectification column is the propane-butane fraction, and the bottom residue contains € 4 hydrocarbons and is stabilized with gasoline. The need to stabilize the product of adsorption units for the removal of gases in a known manner is associated with the installation and operation of additional equipment. In order to eliminate this drawback, it is proposed to stabilize the resulting product directly in the adsorbent layer. Stabilization can be dried, if, after sorption of components of natural or associated gas in the adsorbent layer and before desorbing, through the adsorbent layer, skip the stabilizing agent that does not contain or partially contain light hydrocarbons, including butane, but which contains more hydrocarbons than molecular weight fraction of stabilized gas gasoline. In this case, the Q layer will additionally adsorb heavy hydrocarbons, which will be accompanied by the displacement of lower molecular weight hydrocarbons (ethane, propane, butane). The displacement of light hydrocarbons will be promoted by the frontal chromatographic effect and the fact that the content of the displaced hydrocarbons in the purge gases will be, as provided above, less than their equilibrium partial elasticity over the adsorbed phase. Gasoline gas produced in these adsorption plants, dry gases saturated with Cs hydrocarbons, various waste streams from oil refining processes, and so on can be used as a baling agent to help stabilize gasoline. The gases released in the purging gas can be either directly used as pronanbutane freezing, or reattached to the stripping stream. Purging can be carried out at room or elevated temperature. Not only active carbons, but also other adsorbents can be used as adsorbents. Finally, the process can be carried out both periodically in the stationary layer of the adsorbent, or continuously using fluidized bed and moving bed. As an irimer, the optimal scheme of the process in the stationary layer of the adsorbent is given below. Example. The gas to be stripped enters the adsorber filled with active charcoal. After the layer is saturated, the stream of stripped gases is switched to another parallel working adsorber, and in the first adsorber they stabilize the adsorbed phase — enrich it with relatively heavy hydrocarbons. To this end, a part of the main finished product of the adsorption unit — gas gasoline — is taken from the storage, scooped up and fed to the specified adsorber in the same direction in which the stream moved during the stripping. Upon contact of a hot stabilizing flow (vaporized gasoline) with a solid phase saturated with hydrocarbons, the hydrocarbons of a small molecular weight and, in the first place, ethane, propane and butane, are expelled, replaced. In this way, the solid phase is enriched in more severe carbohydrate, labor. Purging is carried out until the desired degree of removal of the light hydrocarbons is achieved. The gases released from the adsorber during purging have the advantage of propane and butane and, after compression, can be used as the propane-butane fraction. This operation — purging layers of hydrocarbons — is the main distinguishing feature of the proposed process. Further, the adsorber works in the same way as in the well-known method. The adsorbent layer is treated with water vapor, it is formed and cooled. After cooling, the cycle in this m. Adsorber can be repeated anew. During the steam treatment the mixture released from the adsorber is condensed. Condensate is taken out of the condensate and the hydrocarbon fraction is collected, which is a stable gas gasoline. A part of this fraction is used as a purge flow: it performs a closed circus; in this system, the adsorber - storage - evaporator - adsorber system. After several specified cycles have been completed, the composition of the hydrocarbon fraction becomes constant and depends on the duration of the l, blowdown and temperature of the blowing gases. The proposed method makes it possible to abandon the installation of special distillation equipment and thereby reduce the capital costs of the construction of plants for stripping natural gases and the costs of their use. In addition, the elimination of the rectification part makes the stripping plants more mobile and allows them to be installed in the fields with a relatively small gas flow rate. The subject of the invention is a method for producing stabilized gas gasoline from natural and associated gases by adsorbing hydrocarbons from these gases in a stationary layer of solid adsorbent, such as activated carbon, followed by desorption, characterized in that, in order to stabilize gas gasoline directly in the adsorbent layer, through the last desorption pass a stabilizing agent containing hydrocarbons with a molecular weight higher than that of butane, for example, a fraction of stabilized gas gasoline.