Liquefied gas hydrogenation method olefin removal and desulfurization device

Abstract

The device mainly comprises a liquefied gas desulfurization tower, a liquefied gas coalescer, a feeding pump, a reaction heating furnace, a hydrofining reactor, a desulfurization reactor, a reaction effluent / mixed feeding heat exchanger, a reaction effluent air cooler, a reaction effluent cooler, a low-pressure separator and a circulating hydrogen compressor. After hydrogen sulfide carried by the raw materials is removed through the liquefied gas desulfurization tower, the raw materials are boosted through the feeding pump, are mixed with hydrogen, are heated and gasified through the heat exchanger and the heating furnace, enter the hydrofining reactor to be subjected to olefin saturation and mercaptan and other impurity removal reactions, and are subjected to hydrogen sulfide generated by hydrogenation reaction through the desulfurization reactor; a reaction product is subjected to heat exchange and cooling and then enters a low-pressure separator to be subjected to gas-liquid separation, and hydrogenated liquefied gas is obtained through separation. The device can be used for producing refined liquefied gas products with low olefin content and low sulfur content.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquefied gas hydrogenation refining technology in the field of petrochemical industry, specifically relates to a kind of liquefied gas hydrogenation method deolefin desulfurization device. BACKGROUND

[0002] Liquefied gas is a basic chemical raw material in petrochemical industry. The liquefied gas obtained from oil refinery mainly includes one or two of propane, propylene, butane and butene, and a small amount of pentane, pentene and trace sulfide impurities. The liquefied gas associated with oil and gas field basically does not contain olefin, and its main components are ethane, propane, butane and other alkanes, but contains a small amount of hydrogen sulfide and organic sulfur. C3, C4 hydrocarbons in liquefied gas are important raw materials for light hydrocarbon processing industry chain, which can be used to produce ethylene, propylene, maleic anhydride, succinic anhydride, BDO, PBS, MTBE, acrylonitrile, epoxy propane and other chemical products. When liquefied gas is used as raw material for alkane cracking device, olefin will polymerize, cyclize, condense and coking in cracking furnace, as alkane dehydrogenation device raw material, olefin will cause catalyst carbon deposition, as n-butane preparation maleic anhydride device raw material, olefin will cause hot spot in catalyst bed and reactor temperature runaway; and sulfur in liquefied gas will cause downstream device catalyst poisoning and product unqualified, etc. The raw material liquefied gas involved in the utility model patent is mainly liquefied gas byproduct of catalytic cracking, coking and other devices and light hydrocarbon byproduct of oil and gas field. After deolefin desulfurization refining, liquefied gas can be used as chemical raw material with higher value.

[0003] The sulfide contained in liquefied gas is mainly hydrogen sulfide and mercaptan, in addition, it also contains a small amount of carbonyl sulfur, sulfide and disulfide to different degrees. Among them, hydrogen sulfide is basically removed by alcohol amine solution absorption method, while removing mercaptan is the difficulty of liquefied petroleum gas desulfurization and the focus of research and development at home and abroad.

[0004] US patent US2882224 discloses the earliest process developed by UOP for refining light oil products with alkaline solution, Merox process. The basic principle of the technology is to add sulfonated cobalt phthalocyanine or polyphthalocyanine cobalt catalyst in NaOH aqueous solution to make mercaptan in liquefied gas react with NaOH to form sodium mercaptide which is transferred to the alkaline solution. Under the action of sulfonated cobalt phthalocyanine catalyst, mercaptide is oxidized to disulfide by air, and after separation, the alkaline solution can be regenerated and recycled. The technology needs to consume a large amount of caustic soda and catalyst, and the alkaline solution needs to be replaced frequently, not only causing a large amount of alkali residue discharge, but also the process has insufficient desulfurization depth, and the disulfide in the oxidized regenerant alkaline solution is difficult to separate, thus often causing the total sulfur content of the refined liquefied gas to exceed the standard. In view of the above problems, UOP has continuously improved the Merox technology, and so far has formed a series of liquefied petroleum gas desulfurization processes, which are disclosed in patents US2988500, US3108081, US4049572, US4626341. The overall technical progress is to reduce the amount of caustic soda and improve the desulfuration rate.

[0005] Chinese patent 103965984A discloses a method for catalytic desulfurization of liquefied petroleum gas. In the method, liquefied gas is mixed with hydrogen and then subjected to thioetherization reaction in a reactor to convert mercaptan in liquefied petroleum gas into high-boiling thioether compounds, and part of diene is selectively saturated. The method needs to remove hydrogen sulfide and carbonyl sulfur before treatment, and the diene in liquefied gas cannot be completely saturated, which is not suitable for liquefied gas refining that needs to remove olefins and hydrogen sulfide.

[0006] In order to solve the problem of alkaline solution discharge, Chinese patent CN1702157A discloses a method for refining liquefied petroleum gas. The method first removes hydrogen sulfide in liquefied gas with alcohol amine solution, then generates hydrogen sulfide and carbon dioxide by hydrolysis to remove carbonyl sulfur, and removes hydrogen sulfide by flowing through a desulfurizer bed. Liquid oxygen supplementing agent of tert-butyl hydroperoxide is added to oxidize mercaptan into disulfide. Finally, refined liquefied petroleum gas and heavy fraction enriched in disulfide are obtained by gas fractionation and rectification. Although the method can completely convert mercaptan in liquefied petroleum gas by controlling the amount of added oxygen supplementing agent, the decomposition of tert-butyl hydroperoxide produces isobutyl alcohol, which brings difficulties to the separation and purification of liquefied petroleum gas product, and may have adverse effects on its further processing and utilization. In addition, hydrogen sulfide, carbonyl sulfur and mercaptan in liquefied gas need to be removed by three methods, which has a complex process, large device area and high energy consumption.

[0007] Chinese patent CN117757537 A discloses a liquefied gas deep desulfurization method, which first removes hydrogen sulfide in liquefied gas by using alcohol amine solution, then liquefied gas and hydrogen enter the reactor for hydrogenation desulfurization reaction, and after desulfurization, the liquefied gas enters the separator for gas-liquid separation, and the separated liquid phase enters the alcohol amine absorption tower to absorb the sulfide generated in the reaction. The method uses two processes of alcohol amine solution to remove hydrogen sulfide, which is long but cannot guarantee deep removal of hydrogen sulfide, and the catalyst of the method has the characteristics of low olefin saturation rate, which is not suitable for liquefied gas refining requirements that require deep olefin removal and desulfurization.

[0008] Chinese patent CN115216333 A discloses a liquefied gas deep desulfurization method, in which liquefied gas and hydrogen are subjected to selective desulfurization reaction in a fluidized bed reactor, the reaction gas is discharged from the top of the reactor and enters the alcohol amine absorption tower to remove hydrogen sulfide, and the liquefied gas desulfurization product is obtained. The reactor temperature of the method is 50-150℃, the reaction gas directly entering the alcohol amine absorption tower will cause serious foaming in the tower, the reaction pressure is 0.3MPa-2.0MPa, and at a lower pressure, the liquefied gas and hydrogen are both in gas phase and are difficult to separate, which requires deep cooling means to condense the liquefied gas into a liquid, and the method does not have the implementability of industrial application.

[0009] Olefin hydrogenation saturation is the most effective method for removing olefins, and Chinese patent CN106753561 A discloses a liquefied gas hydrogenation method for preparing ethylene cracking material, in which liquefied gas and hydrogen pass through the hydrogenation reactor in parallel flow to carry out olefin saturation reaction in the reactor. The method can remove olefins in liquefied gas, but is not suitable for processing sulfur-containing liquefied gas, on the one hand, sulfur compounds in liquefied gas will cause poisoning of noble metal catalyst, and on the other hand, the method does not involve removing sulfur components in liquefied gas. Utility model content

[0010] The utility model provides a kind of liquefied gas hydrogenation method olefin desulfurization device, olefin saturation and thioalcohol conversion etc. reaction occur under the condition of hydrogenation refining catalyst and hydrogen in crude liquefied gas, the raw material of downstream light hydrocarbon deep processing device is produced, to solve the technical problem that desulfurization depth is low and olefin desulfurization cannot be simultaneously removed in prior art.

[0011] In order to achieve the above purpose, the technical scheme adopted by the utility model is:

[0012] The utility model relates to a liquefied gas hydrogenation method olefin removal desulfurization device, mainly by liquefied gas desulfurization tower, liquefied gas coalescer, feed buffer tank, feed pump, reaction heating furnace, hydrogenation finishing reactor, desulfurization reactor, reaction effluent / mixed feed heat exchanger, reaction effluent air cooler, reaction effluent cooler, low pressure separator and circulating hydrogen compressor are composed, its characterized in that: liquefied gas desulfurization tower communicates with liquefied gas coalescer, feed pump communicates with reaction effluent / mixed feed heat exchanger, reaction effluent / mixed feed heat exchanger communicates with reaction heating furnace, reaction heating furnace communicates with hydrogenation finishing reactor, hydrogenation finishing reactor communicates with desulfurization reactor, desulfurization reactor communicates with reaction effluent / mixed feed heat exchanger, reaction effluent / mixed feed heat exchanger communicates with reaction effluent air cooler, reaction effluent air cooler communicates with reaction effluent cooler, reaction effluent cooler communicates with low pressure separator, low pressure separator communicates with circulating hydrogen compressor.

[0013] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: hydrogenation finishing reactor adopts fixed bed reactor, and liquefied gas and hydrogen gas are in gaseous state in reactor.

[0014] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: reaction effluent / mixed feed heat exchanger sets up multiple series connection, and is distributed as feed vaporization area, temperature rise area.

[0015] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: reaction effluent adopts air cooler+ coolant medium cooler cooling mode, and low pressure separator is equipped with separation inner part, and strengthens gas-liquid two -phase separation, and reduces the light hydrocarbon carrying amount in circulating hydrogen and hydrogen carrying amount in refined liquefied gas product.

[0016] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: desulfurization reactor sets up as one or two, and when setting up two, can series connection or parallel connection switching operation.

[0017] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: desulfurization reactor sets up as one or two, and when setting up two, can series connection or parallel connection switching operation.

[0018] The utility model discloses a liquefied gas hydrogenation method olefin removal desulfurization device, its further feature lies in: desulfurization reactor sets up as one or two, and when setting up two, can series connection or parallel connection switching operation.

[0019] 1) Hydrofining reactor for olefin saturation, hydrodesulfurization reaction, removal of olefins and mercaptans and other impurities in liquefied gas.

[0020] 2) Hydrogen desulfurization, amine liquid absorption of hydrogen sulfide and desulfurizer combined process, while reducing the consumption of desulfurizer, ensure the effect of deep desulfurization.

[0021] 3) High temperature gas phase desulfurization reactor, the penetration sulfur capacity is 2-3 times of low temperature operation, greatly reducing the consumption of desulfurizer.

[0022] 4) Reaction effluent increases cooling medium cooling, strengthen the separation effect of circulating hydrogen and refined liquefied gas, improve the hydrogen purity in circulating hydrogen. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a liquefied gas hydrogenation method of removing olefin desulfurization device schematic view of the utility model;

[0024] The reference signs shown in the figure are: 1-liquefied gas desulfurization tower;2-liquefied gas coalescer;3-feeding buffer tank;4-feeding pump;5-reaction effluent / mixed feed heat exchanger;6-reaction heating furnace;7-hydrofining reactor;8-desulfurization reactor;9-reaction effluent air cooler;10-reaction effluent cooler;11-low pressure separator;12-circulating hydrogen compressor;13-gas distributor;14-inertial separator;15-momentum defoamer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings Figure 1 Further illustrate the utility model:

[0026] As Figure 1 shown, the utility model relates to a kind of liquefied gas hydrogenation method of removing olefin desulfurization device, including liquefied gas desulfurization tower 1, liquefied gas coalescer 2, feeding buffer tank 3, feeding pump 4, reaction effluent / mixed feed heat exchanger 5, reaction heating furnace 6, hydrofining reactor 7, desulfurization reactor 8, reaction effluent air cooler 9, reaction effluent cooler 10, low pressure separator 11 and circulating hydrogen compressor 12 composition;Hydrofining reactor 6 entrance is equipped with gas distributor 13;Low pressure separator 11 entrance is equipped with inertial separator 14, and gas phase outlet is equipped with momentum defoamer 15.

[0027] The top liquefied gas outlet of the liquefied gas desulfurization tower 1 is communicated with the liquefied gas coalescer 2 through a pipeline, the outlet of the liquefied gas coalescer 2 is communicated with the inlet of the feed buffer tank 3, the bottom outlet of the feed buffer tank 3 is communicated with the inlet of the feed pump 4, the outlet of the feed pump 4 is communicated with the cold side inlet of the reaction effluent / mixed feed heat exchanger 5, the cold side outlet of the reaction effluent / mixed feed heat exchanger is communicated with the reaction heating furnace 6, the reaction heating furnace 6 is communicated with the top inlet of the hydrofining reactor 7, the bottom outlet of the hydrofining reactor 7 is communicated with the top inlet of the desulfurization reactor 8, the bottom outlet of the desulfurization reactor 8 is communicated with the hot side inlet of the reaction effluent / mixed feed heat exchanger 5, the hot side outlet of the reaction effluent / mixed feed heat exchanger 5 is communicated with the reaction effluent air cooler 9, the reaction effluent air cooler 9 is communicated with the reaction effluent cooler 10, the reaction effluent cooler 10 is communicated with the low-pressure separator 11, the gas phase outlet of the low-pressure separator 11 is communicated with the inlet of the recycle hydrogen compressor 12, and the outlet of the recycle hydrogen compressor 12 is communicated with the cold side inlet of the reaction effluent / mixed feed heat exchanger 5.

[0028] The liquefied gas hydrodesulfurization device of the utility model refers to the process of Figure 1 The crude liquefied gas is first removed from hydrogen sulfide carried by the liquefied gas desulfurization tower, and then enters the feed buffer tank 3 after removing free water through the coalescer 2, the liquefied gas is pressurized by the feed pump 4, mixed with the recycled hydrogen pressurized by the recycle hydrogen compressor 12, heated to full gas phase through the reaction effluent / mixed feed heat exchanger 5 and the reaction feed heating furnace 6, and then sent to the hydrofining reactor 7, the hydrofining reactor is mainly filled with a refining catalyst, and the olefins in the liquefied gas are saturated by hydrogenation under the action of the catalyst, and the mercaptan is hydrogenated to form hydrogen sulfide. The high-temperature gas phase after the reaction enters the desulfurization reactor 8 to remove hydrogen sulfide in the liquefied gas, and then enters the low-pressure separator 11 after being cooled through the reaction effluent / mixed feed heat exchanger 5, the reaction effluent air cooler 9 and the reaction effluent cooler 10, the gas phase at the top of the low-pressure separator is pressurized by the recycle hydrogen compressor 12, mixed with new hydrogen from outside the device, and then returned to the reaction system, and the liquid phase at the bottom of the low-pressure separator is sent to the liquefied gas separation unit.

[0029] The above is only a typical embodiment of the utility model, and those skilled in the art can make appropriate modifications and improvements on the basis thereof, but the utility model is substantially the same, and also falls within the protection scope of the utility model.

Claims

1. A liquefied gas hydrodeolefining and desulfurization apparatus, mainly composed of a liquefied gas desulfurization tower, a liquefied gas coalescer, a feed pump, a reaction heating furnace, a hydrofining reactor, a desulfurization reactor, a reaction effluent / mixed feed heat exchanger, a reaction effluent air cooler, a reaction effluent cooler, a low-pressure separator, and a recycle hydrogen compressor; characterized in that: The liquefied gas desulfurization tower is communicated with the liquefied gas coalescer, the feed pump is communicated with the reaction effluent / mixed feed heat exchanger, the reaction effluent / mixed feed heat exchanger is communicated with the reaction heating furnace, the reaction heating furnace is communicated with the hydrofining reactor, the hydrofining reactor is communicated with the desulfurization reactor, the desulfurization reactor is communicated with the reaction effluent / mixed feed heat exchanger, the reaction effluent / mixed feed heat exchanger is communicated with the reaction effluent air cooler, the reaction effluent air cooler is communicated with the reaction effluent cooler, the reaction effluent cooler is communicated with the low-pressure separator, and the low-pressure separator is communicated with the recycle hydrogen compressor.

2. The liquefied gas hydrodeolefining and hydrodesulfurizing apparatus according to claim 1, characterized by: The hydrofining reactor is a fixed bed reactor, and the liquefied gas and hydrogen in the reactor are in a gas phase state.

3. The liquefied gas hydrodeolefining and hydrodesulfurizing apparatus according to claim 1, characterized by: The hydrofining reactor is provided with a feed gas phase distributor at the inlet.

4. The liquefied gas hydrodeolefining and hydrodesulfurizing apparatus according to claim 1, characterized by: The reaction effluent / mixed feed heat exchanger is provided with multiple heat exchangers in series, and is divided into a feed vaporization zone and a temperature rising zone.

5. The liquefied gas hydrodeolefining and hydrodesulfurizing apparatus according to claim 1, characterized by: The low-pressure separator is provided with a separation inner part.

6. The liquefied gas hydrodeolefining and hydrodesulfurizing apparatus according to claim 1, characterized by: The desulfurization reactor is provided as one or two, and when two are provided, the two can be operated in series or parallel switching.

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