Energy-saving production method of isooctane

Abstract

The invention relates to the technical field of chemical engineering, in particular to an energy-saving production method of isooctane, which comprises the following steps: mixing etherified C4 and supplemented isobutane, and removing free water; mixing the mixed C4 with hydrogen and carrying out hydrogenation reaction; carrying out light hydrocarbon removal treatment on the hydrogenation reaction product to obtain a C4 fraction; carrying out heat exchange on the C4 fraction and then removing free water; mixing the C4 fraction with a circulating refrigerant and circulating isobutane, and reacting to generate alkylated oil; sequentially carrying out flash evaporation treatment and acid-hydrocarbon separation on a reaction product; carrying out flash evaporation on hydrocarbons after heat exchange; carrying out pressure boosting and heat exchange on the bottom liquid phase of the flash tank, and then conveying to an alkylated oil separation tower; carrying out heat exchange on hydrocarbons of isobutane and n-butane removed from the top, and then conveying the hydrocarbons to a deisobutanizer; and cooling the hydrocarbons from which the n-butane is removed to obtain isooctane, and recycling the isooctane. Circulating water cooling and fractionating tower bottom steam consumption are replaced by heat exchange treatment between materials, energy is saved, and the utilization rate of raw materials is increased.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to an energy-saving production method of isooctane. Background Art

[0002] Isooctane is a colorless, transparent liquid, and an organic compound produced by distilling petroleum in the petroleum industry. As global gasoline standards gradually improve, the requirements for olefins and sulfur content in gasoline are becoming more and more stringent. Isooctane has become a high-quality component of clean and environmentally friendly gasoline because of its excellent properties such as no aromatics and olefins, low sulfur content, and high octane number. Therefore, the development of an efficient and environmentally friendly isooctane production method is of great significance to meet market demand and improve gasoline quality.

[0003] Chinese patent publication number: CN112430175B, discloses a method and device for producing isooctane oil from mixed C4, belonging to the field of petrochemical industry, the method comprises performing a superposition reaction on isobutylene in mixed C4 in a superposition reactor, and separating the obtained superposition reaction product through an isooctene separation tower to obtain isooctene oil, hydrogenating the isooctene oil in a hydrogenation reactor, separating mixed alkanes through a separation tank, and separating the mixed alkanes through an isooctane separation tower to obtain isooctane and heavy alkane oil, isooctane can be used as circulating isooctane, cold isooctane oil and isooctane products, and heavy alkane oil can be used as circulating heavy alkane oil, cold heavy alkane oil and heavy alkane oil products. It can be seen that in the above technical scheme, some heavy alkylate oil will be produced, affecting the product yield, lacking the comprehensive utilization of energy in the product separation process, resulting in large energy consumption. Summary of the invention

[0004] To this end, the present invention provides an energy-saving production method of isooctane, which is used to overcome the problem of high energy consumption caused by lack of comprehensive utilization of energy in the prior art.

[0005] To achieve the above object, the present invention provides an energy-saving production method of isooctane, comprising:

[0006] Step S1, mixing the etherified C4 and supplementary isobutane in a C4 raw material mixer (M102) and removing free water through a coalescing water filter (DR101);

[0007] Step S2, mixing the mixed C4 from which free water has been removed with hydrogen through a hydrogenation feed mixer (M101) and performing a hydrogenation reaction in a hydrogenation reactor (R101);

[0008] Step S3, the hydrogenation reaction product is subjected to light hydrocarbon removal treatment in a light hydrocarbon removal tower (C101) to obtain a C4 fraction;

[0009] Step S4, after heat exchange, the C4 fraction is passed through a raw material dehydrator (D201) to remove free water;

[0010] Step S5, mixing the C4 fraction from which free water has been removed with the circulating refrigerant and the circulating isobutane, and then introducing the mixture into an alkylation reactor (R201) in three streams to generate alkylate oil, wherein sulfuric acid is added before the first stream enters the first stage packing of the alkylation reactor;

[0011] Step S6, sequentially subjecting the reaction product generated in the alkylation reactor to flash treatment and acid hydrocarbon separation, wherein the acid hydrocarbon separation is performed in the flash heat extraction tank (D207) and the acid hydrocarbon coalescence separation tank (D208, D209, D210);

[0012] Step S7, adjusting the circulation rates of the acid and hydrocarbon circulation pumps according to the quality of the alkylate oil product;

[0013] Step S8, the hydrocarbons from which the acid has been removed are subjected to heat exchange between the two streams and then heat exchanged with the top material of the deisobutanizer (C302) before being transported to the reaction product flash tank (D205) for flash evaporation, and the liquid phase at the bottom of the reaction product flash tank (D205) is pressurized and heat exchanged before being transported to the alkylate separation tower (C301);

[0014] Step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65° C. is sent to the deisobutanizer bottom reboiler (E305) for heat extraction and then sent to the refrigeration compressor outlet air cooler (A201), so as to realize the comprehensive utilization of heat, replace the steam use of the deisobutanizer bottom reboiler (E305), and reduce the cooling power consumption of the air cooler (A201);

[0015] Step S10, the removed iso-butane and normal-butane hydrocarbons are transported to a deisobutanizer (C302); the isobutane separated at the top of the deisobutanizer is transported to a reactor for recycling;

[0016] In step S11, the alkylate oil product cooler (E309) at the bottom of the alkylate oil separation tower is cooled to obtain isooctane and store it.

[0017] Further, in step S3, the light hydrocarbon removal process includes:

[0018] The light hydrocarbon components are evaporated from the top of the light hydrocarbon removal tower, condensed and cooled in the light hydrocarbon removal tower top condenser cooler (E106), and then enter the light hydrocarbon removal tower reflux tank (D102);

[0019] The first condensate is pressurized by the light hydrocarbon removal tower reflux pump (P102) and then diverted to the top of the light hydrocarbon removal tower and the liquefied gas tank area according to a first preset ratio.

[0020] Further, in step S5, the three strands include:

[0021] The first stream is mixed with the circulating hydrocarbon pumped out by the hydrocarbon circulating pump, and then enters the first packing section of the alkylation reactor (R201) after being mixed in the mixing section at the bottom of the alkylation reactor;

[0022] The second stream is mixed with the remaining circulating hydrocarbon pumped out by the hydrocarbon circulating pump and enters the second stage packing of the alkylation reactor (R201);

[0023] The third stream enters the alkylation reactor (R201) before the third stage packing.

[0024] Furthermore, a first detection device and a second detection device are respectively provided at the outlet end of the raw material dehydrator (D201) and the hydrocarbon phase outlet end of the flash heat extraction tank (D207), wherein the first detection device is used to detect the amount of C4 fraction removed from free water and the amount of circulating isobutane introduced, and the second detection device is used to detect the content of C4 and isobutane remaining after the alkylation reaction.

[0025] Furthermore, in step S6, the treatment method of the hydrocarbons after the acid hydrocarbon separation is determined according to the separation evaluation value, wherein:

[0026] If the separation evaluation value is less than the preset separation evaluation value, the hydrocarbons are pressurized and returned to the reactor inlet through the hydrocarbon circulation pump (P202), and the circulation rate of the hydrocarbon circulation pump (P202) is adjusted according to the proportion of raw material consumption after the alkylation reaction within the preset time;

[0027] If the separation evaluation value is greater than or equal to the preset separation evaluation value, the hydrocarbons are pressurized by the reaction product pump (P203) and then sequentially passed through the primary acid fine coalescer (D209) and the secondary acid fine coalescer (D210) to remove the remaining trace acid;

[0028] The separation evaluation value is determined according to the ratio of the content of the remaining C4 and isobutane detected by the second detection device to the amount of the C4 fraction and the circulating isobutane introduced by the first detection device;

[0029] The raw material consumption ratio is the ratio of the content of remaining C4 and isobutane detected by the second detection device to the amount of C4 fraction and circulating isobutane introduced by the first detection device.

[0030] Furthermore, the circulation rate of the hydrocarbon circulation pump is adjusted according to the proportion of raw material consumption after the alkylation reaction within a preset time, wherein:

[0031] If the raw material consumption ratio is less than a preset raw material consumption ratio threshold, increasing the circulation rate of the hydrocarbon circulation pump;

[0032] If the raw material consumption ratio is greater than or equal to the preset raw material consumption ratio threshold, the circulation rate of the hydrocarbon circulation pump is reduced.

[0033] Further, in step S8, the two heat exchanges include:

[0034] One stream passes through the C4 / reaction product heat exchanger (E201) for heat exchange with the C4 feedstock fraction from the feedstock pretreatment section;

[0035] The other stream exchanges heat with the refrigerant and circulating isobutane through the circulating isobutane / reaction product heat exchanger (E205);

[0036] The reaction materials after the above two heat exchanges are transported to the top condenser (E307) of the deisobutanizer (C302) to exchange heat with the top gas phase isobutane and then transported to the reaction product flash tank (D205) for flash evaporation.

[0037] Furthermore, in the step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65° C. is sent to the deisobutanizer bottom reboiler (E305) for heat extraction and then is transported to the refrigeration compressor outlet air cooler (A201), thereby realizing comprehensive utilization of heat, replacing the use of steam from the deisobutanizer bottom reboiler (E305), and reducing the cooling power consumption of the air cooler (A201).

[0038] Further, in the step S10, the removal of isobutane and normal butane in the alkylate separation tower (C301) includes:

[0039] The effluent from the top of the alkylate oil separation tower is condensed by the top air cooler (A301) and the top aftercooler (E302), and then enters the alkylate oil separation tower reflux tank (D304) from the bottom of the tank;

[0040] The second condensate is pumped out through the alkylate oil separation tower reflux pump (P303) and returned to the top of the alkylate oil separation tower according to a second preset ratio to serve as reflux and feed to the deisobutanizer tower (C302).

[0041] Further, in the step S11, the deisobutanization in the deisobutanizer (C302) comprises:

[0042] The top effluent is condensed by the deisobutanizer top cooler (E307) and then enters the deisobutanizer reflux tank (D305);

[0043] The second condensate is pressurized by the deisobutanizer reflux pump (P304) and then returned to the top of the deisobutanizer according to a third preset ratio to be mixed with the C4 fraction from which free water is removed and the circulating refrigerant as circulating isobutane, and stored as an isobutane product.

[0044] Compared with the prior art, the present invention has the following beneficial effects: the present invention uses reaction materials to replace circulating water cooling, thereby reducing the energy consumption of the circulating water pump; the present invention changes the separation order of the reaction products, firstly performs alkylation oil separation, and then performs deisobutanization operation, thereby reducing the operating temperature of the deisobutanizer bottom, and utilizes the high-temperature isobutane at the compressor outlet to replace the deisobutanizer bottom steam, thereby reducing the steam power consumption of the device.

[0045] Furthermore, through hydrogenation reaction and fine separation steps, unsaturated compounds and impurities in the raw materials can be effectively removed to improve the purity of the product;

[0046] Furthermore, the light hydrocarbon removal tower and subsequent processing steps achieve effective recovery and utilization of light hydrocarbon components, reducing resource waste;

[0047] Furthermore, the use of multiple heat exchange steps achieves efficient use of energy and reduces energy consumption;

[0048] Furthermore, the treatment method of hydrocarbons after acid hydrocarbon separation is determined according to the separation evaluation value. This flexible control strategy can ensure the best product quality and production efficiency under different operating conditions;

[0049] Furthermore, the low-temperature reaction material can reduce the temperature of the compressed material to a lower level, thereby reducing the work consumption of the compressor;

[0050] Furthermore, the temperature of the reaction materials is further increased after heat exchange, and the reaction products can be further flash vaporized in the flash tank, thereby reducing the flow of the reaction materials to the subsequent distillation tower and reducing the heat source consumption of the distillation tower;

[0051] Furthermore, through the sophisticated separation and treatment steps, the emission of harmful substances is reduced, which contributes to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of an energy-saving production method of isooctane according to an embodiment of the present invention;

[0053] Figure 2 The process flow chart of the energy-saving production method of isooctane according to an embodiment of the present invention;

[0054] In the figure: M102, C4 raw material mixer; D101, C4 raw material buffer tank; P101, C4 raw material feed pump; DR101, coalescing water filter; M101, hydrogenation feed mixer; R101 hydrogenation reactor; E107, light hydrocarbon removal tower bottom material / hydrogenation product heat exchanger; C101, light hydrocarbon removal tower; E106, light hydrocarbon removal tower top condenser cooler; D102, light hydrocarbon removal tower reflux tank; P102, light hydrocarbon removal tower reflux pump; E104, light hydrocarbon removal tower bottom material / reaction feed heat exchanger; E102, hydrogenation product cooler;

[0055] E201, heat exchanger for removing light hydrocarbon C4 / reaction product; D201, raw material dehydrator; R201, alkylation reactor; P201, acid circulation pump; D207, flash heat extraction tank; D208, acid hydrocarbon coalescence separation tank; P202, hydrocarbon circulation pump; D209, primary acid fine coalescer; D210, secondary acid fine coalescer; E205, circulating isobutane / reaction product heat exchanger; D205, reaction product flash tank; P207, reaction product booster pump; K201, refrigeration compressor; P206, acid hydrocarbon coalescence separation tank bottom pump;

[0056] E305, isobutane tower bottom reboiler; A201, air cooler;

[0057] E313, alkylate oil splitter tower feed / condensate heat exchanger; E303, alkylate oil splitter tower feed / alkylate oil heat exchanger; C301, alkylate oil splitter tower; A301, alkylate oil splitter tower top air cooler; E302, alkylate oil splitter tower top aftercooler; D304, alkylate oil splitter tower reflux drum; P303, alkylate oil splitter tower reflux pump; C302, deisobutanizer tower; E307, deisobutanizer tower top cooler; D305, deisobutanizer tower reflux drum; P304, deisobutanizer tower reflux pump; E309, alkylate oil product cooler. DETAILED DESCRIPTION

[0058] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0059] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0060] See also Figure 1 and Figure 2 , which are respectively a flow chart of an energy-saving production method for isooctane according to an embodiment of the present invention; and a process flow chart of an energy-saving production method for isooctane according to an embodiment of the present invention.

[0061] An energy-saving production method of isooctane according to an embodiment of the present invention comprises:

[0062] Step S1, mixing the etherified C4 and supplementary isobutane in a C4 raw material mixer (M102) and removing free water through a coalescing water filter (DR101);

[0063] Step S2, mixing the mixed C4 from which free water has been removed with hydrogen through a hydrogenation feed mixer (M101) and performing a hydrogenation reaction in a hydrogenation reactor (R101);

[0064] Step S3, the hydrogenation reaction product is subjected to light hydrocarbon removal treatment in a light hydrocarbon removal tower (C101) to obtain a C4 fraction;

[0065] Step S4, after heat exchange, the C4 fraction is passed through a raw material dehydrator (D201) to remove free water;

[0066] Step S5, mixing the C4 fraction from which free water has been removed with the circulating refrigerant and the circulating isobutane, and then introducing the mixture into an alkylation reactor (R201) in three streams to generate alkylate oil, wherein sulfuric acid is added before the first stream enters the first stage of filler in the alkylation reactor (R201);

[0067] Step S6, sequentially subjecting the reaction product generated in the alkylation reactor to flash treatment and acid hydrocarbon separation, wherein the acid hydrocarbon separation is performed in the flash heat extraction tank (D207) and the acid hydrocarbon coalescence separation tank (D208, D209, D210);

[0068] Step S7, adjusting the circulation rates of the acid and hydrocarbon circulation pumps according to the quality of the alkylate oil product;

[0069] Step S8, the hydrocarbons from which the acid has been removed are subjected to heat exchange between two streams and then heat exchanged with the top material of the deisobutanizer (C302) before being transported to the reaction product flash tank (D205) for flash evaporation, and the liquid phase at the bottom of the reaction product flash tank (D205) is pressurized and heat exchanged before being transported to the alkylate separation tower (C301);

[0070] Step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65°C is sent to the bottom reboiler (E305) of the deisobutanizer (C302) for heat extraction and then sent to the refrigeration compressor outlet air cooler (A201), so as to realize the comprehensive utilization of heat, replace the use of (E305) steam, and reduce the cooling power consumption of (A201);

[0071] Step S10, the removed iso-butane and normal-butane hydrocarbons are transported to a deisobutanizer (C302); the isobutane separated at the top of the deisobutanizer is transported to a reactor for recycling;

[0072] In step S11, the alkylate oil product cooler (E309) at the bottom of the alkylate oil separation tower is cooled to obtain isooctane and store it.

[0073] Specifically, in step S4, the heat exchange of the C4 fraction includes sequentially passing through a de-light hydrocarbon tower bottoms / hydrogenation product heat exchanger (E107) and a de-light hydrocarbon tower bottoms / reaction feed heat exchanger (E104), cooling to 40°C in a hydrogenation product cooler (E102), and then sending it to a de-light hydrocarbon C4 / reaction product heat exchanger (E201) to exchange heat with the reaction product to 10°C.

[0074] Specifically, in step S6, the acid phase at the bottom of the flash heat extraction tank (D207) is pressurized to 0.8 MPa by the acid circulation pump (P201) and then returned to the bottom inlet of the reactor.

[0075] Specifically, in step S8, the liquid phase flowing out of the tank bottom is pressurized by the reaction product booster pump (P207), and then sequentially passes through the alkylate separation tower feed / condensate heat exchanger (E313) and the alkylate separation tower feed / alkylate heat exchanger (E303) for heat exchange.

[0076] Specifically, in step S3, the light hydrocarbon removal process includes:

[0077] The light hydrocarbon components are evaporated from the top of the light hydrocarbon removal tower (C101), condensed and cooled to 40°C in the light hydrocarbon removal tower top condenser cooler (E106), and then enter the light hydrocarbon removal tower reflux tank (D102);

[0078] The first condensate is pressurized by the light hydrocarbon removal tower reflux pump (P102) and then diverted to the top of the light hydrocarbon removal tower (C101) and the liquefied gas tank area according to a first preset ratio of 9.7:0.3.

[0079] Specifically, in step S5, the three strands include:

[0080] The first stream is mixed with the circulating hydrocarbon pumped out by the hydrocarbon circulating pump, and then enters the first packing section of the alkylation reactor (R201) after being mixed in the mixing section at the bottom of the alkylation reactor;

[0081] The second stream is mixed with the remaining circulating hydrocarbon pumped out by the hydrocarbon circulating pump and enters the second stage packing of the alkylation reactor (R201);

[0082] The third stream enters the alkylation reactor (R201) before the third stage packing.

[0083] Specifically, the three-strand arrangement serves to increase the acid-to-hydrocarbon ratio of the reaction.

[0084] Specifically, the acid phase at the bottom of the flash heat extraction tank (D207) is pressurized by the acid circulation pump (P201) and then returned to the front of the first stage of packing of the alkylation reactor (R201).

[0085] Specifically, a first detection device and a second detection device are respectively provided at the outlet of the raw material dehydrator (D201) and the outlet of the flash heat extraction tank (D207), wherein the first detection device is used to detect the amount of C4 fraction removed from free water and the amount of circulating isobutane introduced, and the second detection device is used to detect the content of C4 and isobutane remaining after the alkylation reaction.

[0086] Specifically, the first detection device and the second detection device are, for example, gas chromatographs, which are not specifically limited, and are used to detect the content of a substance.

[0087] Specifically, in step S6, the treatment method of the hydrocarbons after the acid hydrocarbon separation is determined according to the separation evaluation value, wherein:

[0088] If the separation evaluation value is less than the preset separation evaluation value, the hydrocarbons are pressurized and returned to the reactor inlet through the hydrocarbon circulation pump (P202), and the circulation rate of the hydrocarbon circulation pump (P202) is adjusted according to the proportion of raw material consumption after the alkylation reaction within the preset time;

[0089] If the separation evaluation value is greater than or equal to the preset separation evaluation value, the hydrocarbons are pressurized by the reaction product pump (P203) and then sequentially passed through the primary acid fine coalescer (D209) and the secondary acid fine coalescer (D210) to remove the remaining trace acid;

[0090] Specifically, the separation evaluation value is determined based on the ratio of the content of remaining C4 and isobutane detected by the second detection device to the amount of C4 fraction and circulating isobutane introduced by the first detection device.

[0091] The raw material consumption ratio is the ratio of the content of remaining C4 and isobutane detected by the second detection device to the amount of C4 fraction and circulating isobutane introduced by the first detection device.

[0092] The evaluation value is determined based on the average proportion of effective components in the C4 raw material, where the first evaluation value is 0.88 and the second evaluation value is 0.83.

[0093] Specifically, the circulation rate of the hydrocarbon circulation pump is adjusted according to the proportion of raw material consumption after the alkylation reaction within a preset time of 60 minutes, wherein:

[0094] If the raw material consumption ratio is less than the second evaluation value 0.83, the circulation rate of the hydrocarbon circulation pump is increased;

[0095] If the raw material consumption ratio is greater than the first evaluation value of 0.88, the circulation rate of the hydrocarbon circulation pump is reduced so that the ratio of the remaining C4 and isobutane contents detected by the second detection device to the C4 fraction and circulating isobutane intake detected by the first detection device is between 0.83 and 0.88.

[0096] Specifically, the preset raw material consumption ratio is determined based on the average value measured over a historical period of time, but the above value is not limited thereto, and technicians in this field may also adjust the value based on actual needs.

[0097] Specifically, in step S8, the two heat exchanges include:

[0098] One stream passes through the C4 / reaction product heat exchanger (E201) for heat exchange with the C4 feedstock fraction from the feedstock pretreatment section;

[0099] The other stream exchanges heat with the refrigerant and circulating isobutane through the circulating isobutane / reaction product heat exchanger (E205);

[0100] The reaction materials after the above two heat exchanges are transported to the top condenser (E307) of the deisobutanizer (C302) to exchange heat with the top gas phase isobutane and then transported to the reaction product flash tank (D205) for flash evaporation;

[0101] Specifically, the acid phase flowing out from the bottom of the acid hydrocarbon coalescence separation tank (D208) is pressurized by the acid hydrocarbon coalescence separation tank bottom pump (P206) to discharge the waste acid.

[0102] Specifically, in step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65° C. is sent to the bottom reboiler (E305) of the deisobutanizer (C302) for heat extraction and then sent to the refrigeration compressor outlet air cooler (A201), thereby realizing comprehensive utilization of heat, and the gaseous isobutane at the compressor outlet replaces the steam (E305) for use, thereby reducing the steam consumption of the device and reducing the cooling power consumption of (A201);

[0103] Specifically, in step S10, the removal of isobutane and normal butane in the alkylate separation tower (C301) includes:

[0104] The effluent from the top of the alkylate oil separation tower is condensed by the top air cooler (A301) and the top aftercooler (E302), and then enters the alkylate oil separation tower reflux tank (D304) from the bottom of the tank;

[0105] The second condensate is pumped out through the alkylate oil separation tower reflux pump (P303) and returned to the top of the alkylate oil separation tower at a second preset ratio of 1:1 as reflux and feed to the deisobutanizer (C302). The isooctane at the bottom of the alkylate oil separation tower (C301) is stored as a product.

[0106] Specifically, in the step S11, the deisobutanization in the deisobutanizer (C302) includes:

[0107] The top effluent is cooled to 35°C by the deisobutanizer top cooler (E307) and enters the deisobutanizer reflux tank (D305);

[0108] The second condensate is pressurized by a deisobutanizer reflux pump (P304) and then returned to the top of the deisobutanizer (C302) at a third preset ratio of 1:1 to be mixed with the C4 fraction from which free water is removed and the circulating refrigerant as circulating isobutane, and stored as an isobutane product;

[0109] The normal butane product at the bottom of the deisobutanizer is stored.

[0110] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An energy-saving production method for isooctane, characterized in that: include: Step S1, mixing the etherified C4 and supplementary isobutane in a C4 raw material mixer (M102) and removing free water through a coalescing water filter (DR101); Step S2, mixing the mixed C4 from which free water has been removed with hydrogen through a hydrogenation feed mixer (M101) and performing a hydrogenation reaction in a hydrogenation reactor (R101); Step S3, the hydrogenation reaction product is subjected to light hydrocarbon removal treatment in a light hydrocarbon removal tower (C101) to obtain a C4 fraction; Step S4, after heat exchange, the C4 fraction is passed through a raw material dehydrator (D201) to remove free water; Step S5, mixing the C4 fraction from which free water has been removed with the circulating refrigerant and the circulating isobutane, and then introducing the mixture into an alkylation reactor (R201) in three streams to generate alkylate oil, wherein sulfuric acid is added before the first stream enters the first stage packing of the alkylation reactor; Step S6, sequentially subjecting the reaction product generated in the alkylation reactor to flash treatment and acid hydrocarbon separation, wherein the acid hydrocarbon separation is performed in the flash heat extraction tank (D207) and the acid hydrocarbon coalescence separation tank (D208, D209, D210); Step S7, adjusting the circulation rates of the acid and hydrocarbon circulation pumps according to the quality of the alkylate oil product; Step S8, the hydrocarbons from which the acid has been removed are subjected to heat exchange between the two streams and then heat exchanged with the top material of the deisobutanizer (C302) before being transported to the reaction product flash tank (D205) for flash evaporation, and the liquid phase at the bottom of the reaction product flash tank (D205) is pressurized and heat exchanged before being transported to the alkylate separation tower (C301); Step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65° C. is sent to the deisobutanizer bottom reboiler (E305) for heat extraction and then sent to the refrigeration compressor outlet air cooler (A201), so as to realize the comprehensive utilization of heat, replace the steam use of the deisobutanizer bottom reboiler (E305), and reduce the cooling power consumption of the air cooler (A201); Step S10, the removed iso-butane and normal-butane hydrocarbons are transported to a deisobutanizer (C302); the isobutane separated at the top of the deisobutanizer is transported to a reactor for recycling; In step S11, the alkylate oil product cooler (E309) at the bottom of the alkylate oil separation tower is cooled to obtain isooctane and store it.

2. The energy-saving production method of isooctane according to claim 1, characterized in that: In the step S3, the light hydrocarbon removal process includes: The light hydrocarbon components are evaporated from the top of the light hydrocarbon removal tower, condensed and cooled in the light hydrocarbon removal tower top condenser cooler (E106), and then enter the light hydrocarbon removal tower reflux tank (D102); The first condensate is pressurized by the light hydrocarbon removal tower reflux pump (P102) and then diverted to the top of the light hydrocarbon removal tower and the liquefied gas tank area according to a first preset ratio.

3. The energy-saving production method of isooctane according to claim 2, characterized in that: In step S5, the three strands include: The first stream is mixed with the circulating hydrocarbon pumped out by the hydrocarbon circulating pump, and then enters the first packing section of the alkylation reactor (R201) after being mixed in the mixing section at the bottom of the alkylation reactor; The second stream is mixed with the remaining circulating hydrocarbon pumped out by the hydrocarbon circulating pump and enters the second stage packing of the alkylation reactor (R201); The third stream enters the alkylation reactor (R201) before the third stage packing.

4. The energy-saving production method of isooctane according to claim 3, characterized in that: A first detection device and a second detection device are respectively provided at the outlet of the raw material dehydrator (D201) and the hydrocarbon phase outlet of the flash heat extraction tank (D207), wherein the first detection device is used to detect the amount of C4 fraction removed from free water and the amount of circulating isobutane introduced, and the second detection device is used to detect the content of C4 and isobutane remaining after the alkylation reaction.

5. The energy-saving production method of isooctane according to claim 4, characterized in that: In step S6, the treatment method of the hydrocarbons after the acid hydrocarbon separation is determined according to the separation evaluation value, wherein: If the separation evaluation value is less than the preset separation evaluation value, the hydrocarbons are pressurized and returned to the reactor inlet through the hydrocarbon circulation pump (P202), and the circulation rate of the hydrocarbon circulation pump (P202) is adjusted according to the proportion of raw material consumption after the alkylation reaction within the preset time; If the separation evaluation value is greater than or equal to the preset separation evaluation value, the hydrocarbons are pressurized by the reaction product pump (P203) and then sequentially passed through the primary acid fine coalescer (D209) and the secondary acid fine coalescer (D210) to remove the remaining trace acid; The separation evaluation value is determined according to the ratio of the content of the remaining C4 and isobutane detected by the second detection device to the amount of the C4 fraction and the circulating isobutane introduced by the first detection device; The raw material consumption ratio is the ratio of the content of remaining C4 and isobutane detected by the second detection device to the amount of C4 fraction and circulating isobutane introduced by the first detection device.

6. The energy-saving production method of isooctane according to claim 5, characterized in that: The circulation rate of the hydrocarbon circulation pump is adjusted according to the proportion of raw material consumption after the alkylation reaction within a preset time, wherein: If the raw material consumption ratio is less than a preset raw material consumption ratio threshold, increasing the circulation rate of the hydrocarbon circulation pump; If the raw material consumption ratio is greater than or equal to the preset raw material consumption ratio threshold, the circulation rate of the hydrocarbon circulation pump is reduced.

7. The energy-saving production method of isooctane according to claim 6, characterized in that: In step S8, the two heat exchanges include: One stream passes through the C4 / reaction product heat exchanger (E201) for heat exchange with the C4 feedstock fraction from the feedstock pretreatment section; The other stream exchanges heat with the refrigerant and circulating isobutane through the circulating isobutane / reaction product heat exchanger (E205); The reaction materials after the above two heat exchanges are transported to the top condenser (E307) of the deisobutanizer (C302) to exchange heat with the top gas phase isobutane and then transported to the reaction product flash tank (D205) for flash evaporation.

8. The energy-saving production method of isooctane according to claim 7, characterized in that: In the step S9, the gaseous isobutane flashed out from the flash heat extraction tank (D207) and the reaction product flash tank (D205) enters the refrigeration compressor (K201) for pressure increase, and the compressed high-temperature isobutane at 65° C. is sent to the deisobutanizer bottom reboiler (E305) for heat extraction and then is sent to the refrigeration compressor outlet air cooler (A201), thereby realizing comprehensive utilization of heat, replacing the steam use of the deisobutanizer bottom reboiler (E305), and reducing the cooling power consumption of the air cooler (A201).

9. The energy-saving production method of isooctane according to claim 8, characterized in that: In the step S10, the removal of isobutane and normal butane in the alkylate separation tower (C301) includes: The effluent from the top of the alkylate oil separation tower is condensed by the top air cooler (A301) and the top aftercooler (E302), and then enters the alkylate oil separation tower reflux tank (D304) from the bottom of the tank; The second condensate is pumped out through the alkylate oil separation tower reflux pump (P303) and returned to the top of the alkylate oil separation tower according to a second preset ratio to serve as reflux and feed to the deisobutanizer tower (C302).

10. The energy-saving production method of isooctane according to claim 9, characterized in that: In the step S11, the deisobutanization in the deisobutanizer (C302) includes: The top effluent is condensed by the deisobutanizer top cooler (E307) and then enters the deisobutanizer reflux tank (D305); The second condensate is pressurized by the deisobutanizer reflux pump (P304) and then returned to the top of the deisobutanizer according to a third preset ratio to be mixed with the C4 fraction from which free water is removed and the circulating refrigerant as circulating isobutane, and stored as an isobutane product.

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