RU2618009C1 - Plant for cleaning oil petroleum and natural gas from sulfur-containing compounds - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: plant comprises a filter for cleaning from mechanical impurities, a separator for separating the fine dispersion liquid, a unit for trapping heavy hydrocarbons from associated petroleum gas and drying associated petroleum gas, a deep desulphurization unit, a heat exchanger and a sulfur-containing compounds utilisation unit. The trapping unit is made two-stage, wherein the first stage is designed to clean gas from heavy hydrocarbons and consists of two parallel connected adsorbers operating alternately in the adsorption-desorption mode, and the second stage is designed for drying associated petroleum gas and consists of two parallel connected adsorbers operating alternately in the adsorption-desorption mode. The adsorbers of the trapping unit contain sorbents and are equipped with valves at the inlet and outlet of associated petroleum gas, and operate alternately in the adsorption-desorption mode. The deep desulphurization unit is connected at the inlet with the desiccation stage of the trapping unit and consists of three adsorbers connected by pipelines to valves, which allow to operate both in the series-connected mode and the parallel-connected mode, all adsorbers being equipped with gas analyzers at the outlet.

EFFECT: increasing the cleaning degree of natural or associated petroleum gas from sulfur-containing compounds to the concentration of no more than 5 ppm, increasing the disposal of end products and high environmental friendliness of the plant.

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Description

The invention relates to the gas and oil industries, in particular to installations for the purification of gases from sulfur-containing compounds, and can be used in the preparation of associated petroleum gas (hereinafter APG) and natural gas for consumption.

A known installation of adsorption drying, purification and low-temperature separation of oil gas (RF patent No. 2498174, IPC F25J 3/00, B01D 53/02, publ. 10.11.2013), containing adsorption drying and gas purification unit equipped with adsorbers sequentially included in the technological scheme with zeolite, a low-temperature condensation unit provided with a gas cooling device, further comprising a refrigeration unit connected by a supply pipe and a refrigerant discharge pipe to a purified gas cooling device of the low-temperature unit condensation, a heating and cooling unit for a high temperature coolant connected by pipelines to an adsorption drying and gas purification unit; while the adsorbers of the adsorption drying and gas purification unit are arranged by at least two modules - the first and second, each of which contains at least two adsorbers, connected in parallel to each other by gas supply and exhaust gas pipelines and connected in series to each other with another pipelines for supplying gas to regeneration and removal of saturated gas of regeneration, while said modules are parallel connected to each other by pipelines for supplying gas and removal of purified gas, are also connected in parallel with each other by pipelines for supplying gas of regeneration and removal of saturated gas of regeneration, are also parallel connected to each other by pipelines for supplying and removing high-temperature coolant.

The disadvantage of the installation is the high energy intensity of the desulfurization process and the high sulfur content (above 20 ppm) in the purified gas.

A known installation for cleaning and drying natural and associated petroleum gases with a high content of hydrogen sulfide (RF patent No. 2197318, IPC B01D 53/52, publ. 01/27/2003), containing an absorber for washing and purifying the source gas with a solution of sulfur dioxide, a furnace for burning sulfur and sulfur dioxide gases and sulfur dioxide production; a column for mixing sulfur dioxide with a solvent, additionally equipped with a separator for separating elemental sulfur from the solvent, at least three adsorbers with molecular sieves, a riboiler and recuperative heat This is used for deep cleaning and drying of gas and regeneration of the adsorbent, while the column for mixing sulfur dioxide with a solvent is made in the form of a scrubber with multilayer catalytic nozzles irrigated with water, while the absorber for washing the source gas is also equipped with catalytic nozzles to intensify the chemisorption process (analog) .

The disadvantage of the installation is the high energy intensity of the desulfurization process and the high sulfur content (above 20 ppm) in the purified gas.

A known installation for the purification and drying of natural and associated petroleum gases from hydrogen sulfide (RF patent No. 2176266, IPC C10L 3/10, publ. 11/27/2001), the closest in technical essence to the claimed device and adopted as a prototype.

The installation according to the prototype includes obtaining sulfur dioxide by burning sulfur and sulfur-containing compounds in an oven, mixing it with a solvent, washing the source gas with hydrogen sulfide with this solution and obtaining elemental sulfur and water, removing the sulfur suspension from the absorber and separating sulfur from the solvent, returning the solvent and part of the sulfur in the technological process of purification, while gas purification is carried out in two stages, first, the source gas is first cleaned of hydrogen sulfide in the absorber on the catalytic nozzles by washing and a solution of sulphurous, sulfuric acids and sulfur dioxide obtained by burning regeneration gases and cleaning flue gases with water in a scrubber with catalytic nozzles, at the second stage, deep cleaning and drying of gases on adsorbents - molecular sieves that periodically regenerate and cool the cleaned and dried gas, and regeneration gases after the adsorber are sent to combustion in the furnace.

The installation of cleaning and drying according to the prototype contains a filter for cleaning gas from mechanical impurities and liquid, installed in front of the gas inlet to the absorber, in which the initial gas is purged of hydrogen sulfide, a tank for removing an aqueous suspension of sulfur from the absorber, after which three gas are installed along the gas adsorber with adsorbents - molecular sieves. The purification unit is also equipped with a recuperative heat exchanger for the recovery of heat from regeneration gases, a reboiler for heating the gas supplied to the regeneration of the adsorbent, a water cooler to cool the gas before it is fed to the separator and to separate water condensate and heavy hydrocarbons. The regeneration gas after the separator is sent to the boiler furnace for combustion. The resulting flue gas is fed by a smoke exhauster into a scrubber, the nozzles of which are sprayed with water from a tank using a pump. The resulting weak solution of sulfurous and sulfuric acid is poured into the tank and from there the absorber nozzle is pumped to the irrigation pump. An aqueous suspension of sulfur is separated in a centrifugal separator, water is returned to the tank, and sulfur is returned to the sump.

However, in the known installation, insufficient gas purification takes place (above 20 ppm sulfur), which leads to an increase in the aggressive effect of undesirable impurities on the nodes and parts of devices in which the purified gas is subsequently used. Due to the complexity of the method, the device is bulky and energy intensive. Sulfur from the aqueous suspension is clogged in the nodes of the device, disrupting its operation. And in the event of an emergency stop at an ambient temperature below zero Celsius, water freezes and destroys the components of the device.

The technical problem to which the claimed invention is directed is to increase the degree of purification of natural or associated petroleum gas, increase the efficiency of preparation of the final product before its final use or disposal.

The technical result achieved by the invention is to increase the degree of purification of natural or associated petroleum gas from sulfur-containing compounds to a concentration of not more than 5 ppm.

The technical result is achieved by using a unit for cleaning and drying associated petroleum gas from sulfur-containing compounds, consisting of a filter for removing mechanical impurities and a separator for separating finely dispersed liquids, installed in front of the gas inlet to the adsorber of the unit for capturing heavy hydrocarbons from associated petroleum gas and drying the associated gas from adsorbers containing sorbents and equipped with valves at the inlet and outlet of the associated gas and operating alternately in the adsorption-desorption mode, heat exchanger and and recycling the sulfur-containing compounds. In this case, the unit for collecting heavy hydrocarbons from associated petroleum gas and drying APG is made in two stages, while the first stage for purifying gas from heavy hydrocarbons consists of two parallel adsorbers operating alternately in the adsorption-desorption mode, and the second stage for drying APG also consists of two parallel-connected adsorbers operating alternately in the adsorption-desorption mode, while the device further comprises a deep desulfurization unit, connected at the inlet to the drying stage And consists of at least three adsorbers, connected by pipelines with valves to operate in either series-connected or parallel connected, with all the adsorbers are provided with outlet gas analyzers.

An APG treatment plant containing hydrogen sulfide and mercaptans contains the steps in which:

APG under pressure from 0.6 to 1 MPa is fed into the filter for cleaning from mechanical impurities, fine and dropping liquid;

then the gas enters the adsorbers for trapping heavy hydrocarbons from the gas mixture, for example, activated carbon;

then the gas is sent to a zeolite drying adsorber, where some of the sulfur-containing compounds also settle with moisture;

dried gas is fed to the desulfurization adsorber to completely remove sulfur-containing compounds from the gas using, for example, a solid porous regenerated sorbent, the number of adsorbers is not less than 3, depending on the capacity of the installation;

cleaned and drained APG is sent for further use in household needs or to generator sets for generating electricity;

heavy hydrocarbons from adsorbers working alternately during the regeneration process are separated and sent to combustion for heat;

sulfur-containing compounds from alternately active desulfurization adsorbers released during the regeneration process are first sent to the elementary sulfur production reactor, after which the residues are sent for afterburning to the flare system.

The essence of the invention is illustrated by the following scheme.

Installation, the basic technological scheme of which is shown in FIG. 1, consists of the following elements:

1 - filter for cleaning from mechanical impurities, 2 - separator for removing fine and dropping liquid.

Block A for capturing heavy hydrocarbons from associated gas consists of: 3, 3.1 - adsorbers, 4, 4.1 - valves at the inlet to the adsorbers, valves 5 and 5.1 at the outlet of the adsorbers, 6 and 7 pipelines with valves for supplying coolant, 6.1 and 7.1 - pipelines with valves for the removal of coolant.

Block B for zeolite drying of APG consists of: 8 and 9 — adsorbers, valves at the inlet 10 and 10.1 for supplying pre-cleaned APG, 11 and 11.1 at the outlet of the adsorbers, 12 and 13 pipelines with valves for supplying gaseous coolant, 12.1 and 13.1 pipelines with valves for the removal of coolant.

Block B for deep desulfurization consists of: 14, 15, 16 — adsorbers, 17, 18, 19 — valves for supplying APG after drying from block B, 20 — gas analyzers installed at the outlet of the adsorbers 14, 15, 16, pipelines with valves 21 , 22, 23, connecting the adsorbers of block B to each other to ensure the sequence of operation of the adsorbers, 24, 25, 26 - valves for the outlet of purified gas to the consumer, 27 and 27.1 - pipelines with valves for supplying and discharging the coolant, 28 - purified gas to the consumer, 29, 30 - reactors for the disposal of sulfur-containing compounds.

Installation works as follows. Associated petroleum gas contaminated with sulfur-containing impurities is piped to the unit entrance. APG consumption is automatically regulated, pressure and temperature are controlled. To clean from mechanical impurities, APG passes through filter 1, the degree of pollution of the filter is controlled by the pressure drop across it. Purified from mechanical impurities, the APG from the filter 1 enters the separator 2 to remove droplet moisture and then to block A.

APG purified from mechanical impurities and drop moisture enters alternately in adsorbers 3 and 3.1, which operate alternately in the mode of short-cycle adsorption. Each device is loaded, for example, with activated carbon of the AP-B brand, which allows efficient capture of heavy hydrocarbons. The adsorption-desorption mode is carried out strictly according to the estimated time by automatically switching the corresponding valves. When APG arrives, first in adsorber 3 operating in the mode of adsorption of heavy hydrocarbons, valves 4 and 5 are open, and valves 6 and 6.1 are closed.

Upon reaching the degree of saturation of the sorbent with hydrocarbons, the adsorbers automatically switch: adsorber 3.1 is switched to adsorption mode (valves are opened at inlet 4.1 and APG 5.1 output), adsorber 3 is set into desorption mode.

In desorption mode, the valves are pre-opened at the inlet 6 or 7 and the outlet 6.1 or 7.1 of the coolant. Next, the cycle repeats.

During adsorption and desorption, the pressure and temperature in the adsorbers are continuously monitored.

Purified from heavy hydrocarbons, the APG then goes to block B at the drying stage in the adsorbers 8 and 9, which operate alternately. Each adsorber is loaded, for example, with Na A zeolite, which makes it possible to reach the dew point of the dried gas.

Upon reaching the degree of saturation of the adsorbent in the adsorber 8 with moisture, automatic switching takes place: the adsorber 9 is transferred to the adsorption mode (valves 10.1 and 11.1 open and the valves 13 and 13.1 are closed), the adsorber 8 is switched to the desorption mode (valves 10 and 11 are closed and the valves are closed 12 and 12.1).

Dried APG from the drying stage enters block B to the stage of capturing sulfur-containing compounds in adsorbers 14, 15, 16, working alternately in pairs.

Each adsorber is loaded with an adsorbent, which allows efficient extraction of sulfur-containing compounds from APG.

The APG first enters the adsorber 14. In this case, the valve at the inlet 17 and the outlet of the APG 21 is open, the valves at the inlet 27 and the outlet of the heat transfer medium 27.1 to the adsorber 14, 15 are closed, the valve 24 is closed. Valve 25 is open and valve 22 is closed. There is a process of collecting sulfur-containing compounds from APG on the sorbent layer in apparatus 14. Next, APG from 15 enters 15 to provide more complete purification. After 15, the cleaned APG is sent to consumer 28. Upon reaching the saturation degree of the adsorbent in 14 sulfur-containing compounds (according to the readings of a gas analyzer 20 or an industrial chromatograph), the adsorbers automatically switch: the adsorber 15 becomes the first along the APG (valves 18, 22, 26 open at the inlet and outlet APG, valves 17, 21, 23, 25 are closed), the adsorber 16 is transferred to the adsorption mode (while valves 27 and 27.1 with the adsorber 16 are closed). The adsorber 14 is transferred to the desorption mode (while the valves 27 and 27.1 with the adsorber 14 open). Further, as the first adsorber is saturated during the purification of the gas, pairwise switching of the adsorbers occurs similarly (14 and 15 — adsorption, 16 — desorption, 15, 16 — adsorption, 14 — desorption, 16 and 14 — adsorption, 15 — desorption).

In desorption mode, valves 27 and 27.1 (of this adsorber) open at the inlet and outlet of the coolant - the process of extracting sulfur-containing compounds from the sorbent is in progress. Next, the coolant enters the stage of utilization of sulfur-containing compounds in the reactor 29 or 30. At the end of the desorption process, the adsorber is automatically transferred to the adsorption mode in the manner described above.

Sulfur-containing compounds from the stage of capture of sulfur-containing compounds during the regeneration process go to the stage of utilization of sulfur-containing compounds, where they are mixed with air and transferred to reactors 29 and 30, which operate alternately. Each reactor is loaded with a catalyst allowing efficient oxidation of sulfur-containing compounds to elemental sulfur. As it saturates, it automatically switches to another reactor.

To determine the content of components at the inlet and outlet of the adsorbers and reactors, automatic gas analyzers are installed.

The inventive installation allows for comprehensive multi-stage drying and purification of gas, which allows to maximize the efficiency of preparation of the final product before its final disposal. All waste products are disposed of, i.e. non-waste and, as a result, high environmental friendliness of the claimed installation.

Claims (1)

Installation for purification and drying of associated petroleum gas from sulfur-containing compounds, consisting of a filter for purification from mechanical impurities and a separator for separating finely dispersed liquid installed in front of the gas inlet to the adsorber of the unit for trapping heavy hydrocarbons from associated petroleum gas and for drying APG consisting of adsorbers containing sorbents and equipped with valves at the inlet and outlet of the APG and operating alternately in the adsorption-desorption mode, the heat exchanger and the sulfur-containing compounds recovery unit, characterized in that the unit for collecting heavy hydrocarbons from associated petroleum gas and drying APG is made two-stage, while the first stage for cleaning gas from heavy hydrocarbons consists of two parallel-connected adsorbers operating alternately in the adsorption-desorption mode, and the second stage for drying APG also consists of two parallel-connected adsorbers operating alternately in the adsorption-desorption mode, while the device further comprises a deep desulfurization unit, connected at the inlet to the drying stage , and consists of at least three adsorbers connected by pipelines to valves, allowing operation both in series and in parallel, while all adsorbers are equipped with gas analyzers at the outlet.

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