SU816522A1 - Method of drying hydrocarbon gas - Google Patents

Description

one

The invention relates to methods for drying hydrocarbon gases and may find its application in the oil and gas industries.

A known method of purifying natural gas, followed by desalting of the spent glycol by precipitation, salts under the action of a water-soluble organic solvent and further separation of the precipitate.

The main disadvantage of this method is that its efficiency is not high enough, since it significantly prolongs the period of equipment maintenance-free operation, but the presence of salts in glycols is not completely eliminated.

The closest to the described invention to the technical essence and the achieved result is a method of drying the hydrocarbon gas. by contacting it with a desiccant-glycol followed by regenerating the spent glycol by stripping. The main drawback of the described method of drying the gas is gradual salinization of DEG (diethylene glycol, and if 4% of salts are present, its desiccation ability

Psoday abruptly and it becomes practically unsuitable for gas drying. In addition to this drawback, the presence of mineral salts in DEG significantly increases its corrosion activity.

As a result of the salinization of DEG, it eventually becomes unusable and is discharged along with the wastewater. Taking into account that DEG is an expensive desiccant and a significant part of it is acquired abroad, DEG losses from salinization substantially increase the cost of drying natural gas.

The purpose of the invention is to develop such a method of drying the gas, which would reduce the loss of diethylene glycol.

The goal is achieved by drying the hydrocarbon gas by contacting it with a glycol desiccant followed by

regeneration of spent glycol, in which the regeneration is carried out on ion-exchange filters.

In this case, KU-2 cation exchanger and AB-17 anion exchanger are used as ion-exchange filters. After the detection of ion leakage, the deionization process either terminates with cfOBceM, or the flow of the initial liquid (DEG solution) is switched to similar columns with fresh ion exchangers. The use of additional columns with ion exchangers allows the desalting of the diethylene glycol solution to be carried out continuously. After the columns with ion exchangers are disconnected, they are washed with water, which is supplied to the columns from the bottom up with a certain speed. The water entering the columns boosts ion exchangers and, flowing out through the upper openings in the columns, carries with it sediments of sparingly soluble substances. After washing, the ion exchangers produce their regeneration. The regeneration of the cation exchanger is carried out with a solution of amalin chloride, and the anion exchanger with alkali (NaOH) from the bottom up. Both regenerating solutions are removed from the top of the columns. the regenerated and washed ion exchangers are mixed with gas sparging through the columns. The gas supply to the bottom of the columns creates favorable conditions for uniform mixing of the suspension of ion exchangers in water. Thereafter, columns with ionites are ready for the process, deionization. The life of the ion exchangers is 8-10 years, with anion exchangers and cation exchangers at 5% / g being envisaged. Consumption of ammonium chloride and Alkali is 320 tons / g each. Before applying the stage of regeneration of DEG during gas drying, the annual loss of DEG was at least 3000 tons per year. Moreover, it is known that most of the DEG used in the country comes from abroad and its cost is about 70 r per 1 ton. Therefore, the damage only from the DEG dump due to its salinity is 3000 t / g, i.e. over 2 mln. An echo does not take into account damage from the foundations of all gas drying equipment for its repair. Example. Gas from gas wells in the amount of about 14 million nmusut. It is fed to the separators, where the main mass of hydrocarbon condensate and formation saline water is separated from it. The degree of mineralization of this water is quite high and currently amounts to 33 g / l, and the mineralization of water rather significantly increases with time. From the separators, the liquid is directed to the separators, from where after the sludge the condensate is sent to stabilize and the formation water is discharged. The gas after the separator is sent to absorbers, in which it contacts with a fresh solution of DEG recovered in a stripping column. The total consumption of DEG involved in. The hoop is 6120 kg / h. . Out of the absorber, a saturated solution of DEG is sent for regeneration to a stripping column. The salt content in DEG increases continuously. As already noted above, when the content of salts in DEG in an amount higher than 4 wt., Its drainage capacity practically becomes equal to zero. However, DEG desalination is started at a salt concentration of 2%, since at a Bbsue salt content of 2 wt.%, They are deposited on the surface of the pipes, in the heat exchanger, the Stripping column, the absorber, and other utilities. Thus, upon reaching the concentration of salts in the DEG up to 2 wt.%, The DEG is sent to two columns with ion-exchange filters. Ion exchangers were loaded into columns using a belt elevator from the upper manhole. After their filling, the ion exchangers ionize from bottom to top for 30 minutes with the help of gas, the gas velocity is no more than 0.05 m / s. Solution .DEG pe-. By entering into the columns with ionites for desalting after the absorber, they are cleaned from mechanical impurities using filters. Then, the DEG solution, purified from impurities, enters the column filled with cation exchanger KU-2, where sodium cations are replaced with hydrogen cations. Thereafter, the DEG solution is fed to the AV-17 anion exchanger, where the chlorine ions are replaced with a hydroxyl group. About 40 tons of DEG are passed through the filter during the day. Filters operate periodically with a solution supply rate of 10 t / h at a pressure of 6 kg / cm and temperature. The saturation time is 10 hours; the time is Ryo-. radio 13h. The saturated cation exchanger and anion exchanger undergo regeneration after the columns are disconnected, the remaining between the DEG ionite granules is displaced from the columns by gas supplied from the top of the columns. DEG displacement duration occurs within one hour. After displacing the DEG, the stage of regeneration of ion exchangers begins: the regeneration of the cation exchanger KU-2 is carried out with a 5% solution of ammonium chloride (NH4C1) at a rate of 5. After regeneration, the cation exchanger is washed by supplying water. After that, the cation layer is loosened with the help of

gas upwards with a speed of 0.05 m / s.

At the same time: with this, AB-17 anion exchanger is regenerated with the help of NaOH solution.

Claims (2)

1. A method of drying a hydrocarbon gas by contacting it with a desiccant-glycol, followed by regeneration of the spent glycol, characterized in that, in order to reduce the loss of desiccant. glycol regeneration is carried out on ion exchangers. 2. The method according to item 1, I distinguish. As well as with the fact that cation exchanger KU-2 and anion exchanger AB-17 are used as ion-exchange filters. Sources of information taken into consideration during the examination 1. US patent W 3991342, cl. 260-637, 09/20/74. 2. Makogon, Yu. F., Sarkis, N. A. G. Prevention of hydrate formation during gas production and transportation. M., Nedra, 1966, p. 69-85 (prototype).