CN114736712A - Device and method for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin to trace amount - Google Patents
Device and method for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin to trace amount Download PDFInfo
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- CN114736712A CN114736712A CN202210439881.1A CN202210439881A CN114736712A CN 114736712 A CN114736712 A CN 114736712A CN 202210439881 A CN202210439881 A CN 202210439881A CN 114736712 A CN114736712 A CN 114736712A
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- 239000012188 paraffin wax Substances 0.000 title claims abstract description 154
- 150000004945 aromatic hydrocarbons Chemical class 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000000926 separation method Methods 0.000 claims abstract description 150
- 239000002808 molecular sieve Substances 0.000 claims abstract description 122
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims abstract description 115
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 85
- 150000001875 compounds Chemical class 0.000 claims abstract description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000001301 oxygen Substances 0.000 claims abstract description 44
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 21
- 150000001335 aliphatic alkanes Chemical class 0.000 claims abstract description 14
- 238000001179 sorption measurement Methods 0.000 claims description 98
- 238000010992 reflux Methods 0.000 claims description 62
- 239000007788 liquid Substances 0.000 claims description 49
- 239000000047 product Substances 0.000 claims description 39
- 239000001257 hydrogen Substances 0.000 claims description 19
- 229910052739 hydrogen Inorganic materials 0.000 claims description 19
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 16
- 239000001993 wax Substances 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 229930195733 hydrocarbon Natural products 0.000 claims description 10
- 150000002430 hydrocarbons Chemical class 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 239000003245 coal Substances 0.000 claims description 9
- 238000007599 discharging Methods 0.000 claims description 9
- 229940057995 liquid paraffin Drugs 0.000 claims description 7
- 239000007795 chemical reaction product Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- -1 molecular sieve oxygen compound Chemical class 0.000 claims description 5
- 230000008929 regeneration Effects 0.000 claims description 5
- 238000011069 regeneration method Methods 0.000 claims description 5
- 239000007791 liquid phase Substances 0.000 claims description 4
- 239000000178 monomer Substances 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims description 3
- 150000001491 aromatic compounds Chemical class 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 2
- 125000003118 aryl group Chemical group 0.000 claims description 2
- 239000003054 catalyst Substances 0.000 claims description 2
- 238000006555 catalytic reaction Methods 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000003795 desorption Methods 0.000 description 4
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- 229910052751 metal Inorganic materials 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000000443 aerosol Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
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- 150000002431 hydrogen Chemical class 0.000 description 2
- 239000002917 insecticide Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 150000002927 oxygen compounds Chemical class 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000005899 aromatization reaction Methods 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
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- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000077 insect repellent Substances 0.000 description 1
- 238000006317 isomerization reaction Methods 0.000 description 1
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- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000013520 petroleum-based product Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000013464 silicone adhesive Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
- C10G67/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only
- C10G67/06—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only including a sorption process as the refining step in the absence of hydrogen
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
- C10G2300/20—Characteristics of the feedstock or the products
- C10G2300/201—Impurities
- C10G2300/202—Heteroatoms content, i.e. S, N, O, P
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention discloses a device and a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace, wherein the device provided by the invention comprises the following steps: before the separation system of normal and isomeric alkane, a hydrogenation dearomatization system and a molecular sieve oxygen-containing compound removal system are arranged, so that the content of aromatic hydrocarbon and oxygen-containing compound in normal and isomeric alkane can be effectively reduced, then the material without aromatic hydrocarbon and oxygen-containing compound is separated by the normal and isomeric separation system, thus obtaining corresponding series products, and greatly improving the product quality and the application range. The device provided by the invention is used for separating Fischer-Tropsch paraffin to obtain high-purity normal paraffin and isoparaffin. The experimental result shows that the device can reduce the content of aromatic hydrocarbon to below 5ppm, reduce the content of oxygen-containing compounds to below 2ppm and reduce the content purity of single components to not less than 98.5 percent.
Description
Technical Field
The invention relates to the technical field of coal chemical industry, in particular to a device and a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to a trace amount.
Background
The normal and isoparaffins are mainly applied to the high-end environmental protection product fields such as daily chemical products, high-grade paint, detergents, chlorinated paraffin and the like. The environment-friendly paint can be widely applied to industries such as chlorinated paraffin, dibasic acid, coating, paint thinner, metal cleaner, textile printing and dyeing auxiliary agent, metal processing, aerosol, high-end cleaning, environment-friendly coating, parting medium, cosmetics, deep sea drilling fluid, aluminum foil processing, insecticide, adhesive, mosquito-repellent incense, printing ink, silicone adhesive, PVC viscosity reducer, aerosol insecticide, metal processing, high-grade paint and the like. In addition, isoparaffins can replace a variety of solvents for use in downstream markets.
The prior art generally uses molecular sieve adsorption technology to achieve separation of normal paraffins from non-normal paraffins. However, with the growing environmental protection concept of people, the market demand for environmental protection products is promoted to be synchronously promoted, although the raw material used for adsorption separation in the process is a crude liquid wax product obtained by coal indirect liquefaction, which is relatively more environmental-friendly than petroleum-based products, the content of aromatic hydrocarbon and oxygen-containing compounds in the crude liquid wax product is not removed or reaches a trace amount, and the adsorption efficiency of the crude liquid wax product is influenced by long-term application of the crude liquid wax product on a molecular sieve, so that the products such as normal paraffin and isoparaffin with high purity and good quality cannot be obtained finally. The content of aromatic hydrocarbon and oxygen-containing compounds in normal and isoparaffin parts obtained by the separation of the existing molecular sieve adsorption technology is respectively about 300ppm and 40ppm through detection, the aromatic hydrocarbon content is not in accordance with the industrial standard of less than 50ppm and the use requirement of the molecular sieve is less than 2ppm, the product with high aromatic hydrocarbon content has large smell, the product with high oxygen-containing compound content is easy to discolor, oxidize and damage the molecular sieve, and the product cannot meet the environmental protection requirement and is applied to the molecular sieve, and is difficult to be sold as a high-end product.
In view of this, the invention is particularly proposed.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a device and a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to a trace amount.
The invention is realized by the following steps:
the invention provides a device for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace, which comprises: the molecular sieve adsorption system mainly comprises: the device comprises a light component removing tower, a heavy component removing tower, a hydrogenation feeding buffer tank, a hydrogenation dearomatization reactor, a stripping tower, a molecular sieve oxygen-containing compound removing tank and an adsorption tower, wherein a discharge port of the light component removing tower is connected with a feed port of the heavy component removing tower; the adsorption tower is provided with an extract liquid discharge port and a raffinate liquid discharge port; the extract liquid discharge port and the raffinate discharge port of the adsorption tower are connected with the extract liquid feed port and the raffinate feed port of the normal paraffin and isoparaffin separation system, and the extract liquid and the raffinate are respectively separated in the normal paraffin and isoparaffin separation system.
The invention also provides a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace by using the device, which comprises the following steps: removing oxygen-containing compounds and aromatic hydrocarbons in Fischer-Tropsch paraffin by using a molecular sieve adsorption system to obtain extract liquid and raffinate, and separating the extract liquid and the raffinate by using a normal paraffin and isoparaffin separation system to obtain corresponding normal paraffin component products and isoparaffin products.
The invention has the following beneficial effects:
the invention provides a device and a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace, wherein the device provided by the invention comprises the following steps: a hydrogenation dearomatization system and a molecular sieve oxygen-containing compound removal system are arranged in front of a separation system of normal and heterogeneous alkanes in Fischer-Tropsch alkanes, so that the content of aromatic hydrocarbons and oxygen-containing compounds in the normal and heterogeneous alkanes can be effectively reduced, then materials of the aromatic hydrocarbons and the oxygen-containing compounds are separated by the normal and heterogeneous separation system, and a corresponding series of products are obtained, and the product quality and the application range are greatly improved. The device of the invention is used for separating Fischer-Tropsch paraffin to obtain corresponding series products of high-purity normal paraffin and isoparaffin.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic diagram of an apparatus for reducing the adsorption of oxygen-containing compounds to trace amounts in an alkane oil according to the present invention, wherein the numbers of the attached drawings are as follows: 1-0-light component removing tower and 1-1-heavy component removing tower; 1-2-hydrogenation feeding buffer tank, 1-3-hydrogenation dearomatization reactor, 1-4-hydrogenation stripping tower, 1-5-water cooler, 1-6-reflux tank, 1-7-molecular sieve oxygen compound removing tank, 1-8-molecular sieve feeding buffer tank, 1-9-rotary valve, 1-10-first adsorption tower, 1-11-second adsorption tower, 1-12-heat exchanger and 1-13-hydrogen buffer tank;
FIG. 2 is a schematic diagram of a normal-isomerization separation system according to the present invention; the reference numbers: 1-9-rotary valve, 2-1-isoparaffin feed buffer tank, 2-2-raffinate column, 2-3-first isoparaffin separation column, 2-4-second isoparaffin separation column, 2-5-raffinate column mid-section reflux, 2-6-reflux tank, 2-7-normal paraffin feed buffer tank, 2-8-extract liquid column, 2-9-first normal paraffin separation column, 2-10-second normal paraffin separation column, 2-11-third normal paraffin separation column, 2-12-fourth normal paraffin separation column, 2-13-reflux tank, 2-14-extract liquid column mid-section reflux, 2-15-third abnormal paraffin separation column, 2-16-fifth n-alkane separation column.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The invention aims to provide a device and a method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to a trace amount, wherein the device can reduce the content of aromatic hydrocarbon to below 5ppm and the content of oxygen-containing compounds to below 2ppm, effectively improve the product quality and the risk resistance of a product market, and generate higher economic benefit and environmental protection benefit.
The coal-based Fischer-Tropsch synthetic liquid wax is a liquid hydrocarbon mixture which is prepared by processing oil products and mainly comprises normal paraffin by taking coal-based Fischer-Tropsch synthetic diesel oil fraction as a raw material, wherein the liquid hydrocarbon mixture comprises a small amount of isoparaffin.
In order to achieve the above object of the present invention, the following technical solutions are adopted.
In a first aspect, an embodiment of the present invention provides an apparatus for reducing the content of aromatic hydrocarbons in fischer-tropsch paraffins to a trace amount, including a molecular sieve adsorption system and a normal paraffin and isoparaffin separation system, where the molecular sieve adsorption system mainly includes: the device comprises a light component removing tower, a heavy component removing tower, a hydrogenation feeding buffer tank, a hydrogenation dearomatization reactor, a stripping tower, a molecular sieve oxygen-containing compound removing tank and an adsorption tower, wherein a discharge port of the light component removing tower is connected with a feed port of the heavy component removing tower; the molecular sieve feeding buffer tank is connected with a molecular sieve adsorption system, the molecular sieve adsorption system, wherein:
the method comprises the following steps of removing components below C10 from the top of a light component removal tower by using Fischer-Tropsch paraffin as a raw material, then entering the middle of a heavy component removal tower, removing part of light components and heavy components from the heavy component removal tower, removing the components above C15 from the bottom of the heavy component removal tower, removing the light components and the heavy components from the light component removal tower and the heavy component removal tower to obtain a normal paraffin molecular sieve material and an isoparaffin molecular sieve material (usually the components between C10 and C15, and the part of components do not contain the light components and the heavy components and greatly reduce the influence of the light components and the heavy components on a hydrogenation and dearomatization reaction) which are composed of specific proportions and carbon numbers, and then enabling the molecular sieve material to enter a hydrogenation feeding buffer tank. The first heat exchanger is a heat exchanger for exchanging heat between feeding materials and reaction products, the second heat exchanger is a heat exchanger for exchanging heat between the feeding materials and low-temperature hot oil, preferably, a feeding hole of the first heat exchanger is connected with a discharging hole of a side-draw pump or a raffinate tower of the heavy component removal tower, a discharging hole of the first heat exchanger is connected with a feeding hole of the second heat exchanger, a heat exchange medium of the first heat exchanger is a molecular sieve material subjected to hydrogenation and dearomatization, and a discharging hole of the second heat exchanger is connected with a feeding hole of a hydrogenation buffer tank. More preferably, after passing through the two heat exchangers, the molecular sieve material is heat exchanged to 150-200 ℃ and enters a hydrogenation buffer tank.
A feed inlet of the hydrogenation feed buffer tank is connected with a discharge outlet of a side pump of the de-heavy column; the hydrogenation feeding buffer tank can ensure the inlet pressure of the hydrogenation feeding pump, the hydrogen is mixed with hydrogen in proportion after being pressurized by the hydrogenation feeding pump, and the mixture enters the hydrogenation dearomatization reactor to carry out the hydrogenation dearomatization reaction, preferably, the hydrogenation dearomatization reaction is carried out under the working conditions of 2.4-2.6Mpa and 225-240 ℃.
The hydrogenation and dearomatization reactor is characterized in that a feed inlet is formed in the bottom of the hydrogenation and dearomatization reactor, the feed inlet is connected with a discharge outlet of a hydrogenation buffer tank and is used for introducing a molecular sieve material into the hydrogenation and dearomatization reactor, the molecular sieve material enters the hydrogenation and dearomatization reactor to perform selective liquid phase hydrogenation under the action of a hydrogenation catalyst, and aromatic compounds with the content of about 300ppm in the molecular sieve material are subjected to hydrogenation saturation and converted into naphthenic hydrocarbons through hydrogenation catalytic reaction, so that the aromatic content of the molecular sieve material is reduced to below 10 ppm. The top of the hydrogenation dearomatization reactor is provided with a discharge hole, and molecular sieve materials after dearomatization are discharged and enter a stripping tower.
A feed inlet of the stripping tower is connected with a discharge outlet at the top of the hydrogenation and dearomatization reactor, the stripping tower is used for ensuring that dissolved hydrogen which does not participate in the reaction in the stripping tower is flashed out, a reflux device is arranged at the top of the stripping tower, the reflux device is a reflux tank, and meanwhile, the reflux tank is provided with a light component recycling facility; the inventor finds that in the actual production process, cracked hydrocarbons exist in the reflux tank arranged at the top of the stripping tower, and return the cracked hydrocarbons in the reflux tank into the light component removal tower again through a newly added pipeline, and then carry out hydrogenation dearomatization reaction again, so that the reduction of the content of aromatic hydrocarbons in normal isoparaffin is facilitated; a heat exchanger is also arranged on a pipeline between the stripping tower and the molecular sieve oxygen-containing compound removal tank, a discharge port of the heavy component removal tower is connected with the hydrogenation feeding buffer tank through the heat exchanger, residual heat in the heavy component removal tower is recovered through the heat exchanger and returns to the hydrogenation feeding buffer tank, so that the temperature of hydrogen in the buffer tank is increased, and the heated hydrogen enters the hydrogenation dearomatization reactor to accelerate dearomatization reaction, thereby improving the dearomatization rate; the pressure head of the hydrogenation feed pump can be guaranteed to drop by the hydrogenation feed buffer tank, and the hydrogen is mixed with hydrogen in proportion after being pressurized by the hydrogenation feed pump, and the hydrogen buffer tank is further arranged between the hydrogenation feed buffer tank and the hydrogenation dearomatization reactor, so that the hydrogen amount entering the hydrogenation dearomatization reactor can be increased, and the hydrogenation dearomatization reaction efficiency can be improved.
The device comprises a molecular sieve oxygen-containing compound removing tank, wherein a feed inlet is formed in the bottom of the molecular sieve oxygen-containing compound removing tank and is connected with a discharge outlet in the bottom of a stripping tower, preferably, a 13X-type molecular sieve is arranged in the molecular sieve oxygen-containing compound removing tank, oxygen-containing compounds and aromatic hydrocarbons are adsorbed in a full liquid phase under the working conditions of 40-120 ℃ and 0.3-0.7MPA, the oxygen-containing compounds are reduced to be below 2PPm from 40PPm through molecular sieve adsorption, and the aromatic hydrocarbons are reduced to be below 5PPm again. More preferably, a molecular sieve regeneration system is arranged at the bottom of the molecular sieve oxygen-containing compound removal tank, the regeneration of the molecular sieve after the molecular sieve is saturated by adsorption is realized by desalted water, hot nitrogen and a desorption agent, and a regenerated product is discharged into the dirty oil tank. More preferably, the top of the molecular sieve oxygen-containing compound removing tank is provided with a discharge hole connected with a feeding pipeline of the molecular sieve feeding buffer tank, the molecular sieve oxygen-containing compound removing tank is connected with the molecular sieve feeding buffer tank through a pipeline, and molecular sieve materials enter the adsorption tower from the molecular sieve feeding buffer tank.
The adsorption tower comprises a first adsorption tower and a second adsorption tower, feeding and discharging of the first adsorption tower and the second adsorption tower are controlled in a balanced mode through rotary valves, and the rotary valves are used for controlling feeding and discharging of the first adsorption tower and the second adsorption tower in a balanced mode. 5A type molecular sieves are filled in the first adsorption tower and the second adsorption tower and are used for adsorbing and separating crude liquid wax obtained by indirect liquefaction of coal under the working conditions of temperature of 170-190 ℃, pressure of 2.2-2.6Mpa and treatment capacity of 30-50t/h to obtain extract liquid of high-purity normal alkane and desorbent and raffinate of high-purity isoparaffin and desorbent.
As a preferred embodiment of the invention, the molecular sieve adsorption system comprises a heavy component removal tower, a molecular sieve feed-light component removal tower bottom oil heat exchanger, a molecular sieve feed buffer tank, a molecular sieve feed heater, a fine filter, a rotary valve, a first adsorption tower, a second adsorption tower, a extract and raffinate feed mixer, an extract and raffinate feed flash tank and an extract and raffinate tower system (namely a normal paraffin and isoparaffin separation system).
The extract liquid and the raffinate separated by the molecular sieve adsorption system respectively enter from the feed inlets of the extract liquid tower and the raffinate tower, and the extract liquid tower and the raffinate tower are respectively used for separating the desorbent in the extract liquid and the raffinate to respectively obtain the normal paraffin and the isoparaffin. The bottom of the raffinate tower is provided with a discharge hole, and the separated normal paraffin and isoparaffin are discharged from the discharge hole at the bottom of the tower and respectively enter a normal paraffin and isoparaffin re-separation system, so that corresponding series products are obtained.
The normal paraffin and isoparaffin separation system is characterized in that extract and raffinate separated by the molecular sieve adsorption system respectively enter from feed inlets of an extract tower and a raffinate tower, and the extract tower and the raffinate tower are respectively used for separating desorbents in the extract and the raffinate to respectively obtain normal paraffin and isoparaffin. The top of the extraction liquid and the top of the raffinate tower are provided with reflux devices, each reflux device comprises an air cooler, a water cooler and a reflux tank which are sequentially connected, a feed inlet of the air cooler is connected with an outlet of the top of the raffinate tower, an outlet of the reflux tank is connected with an ejection opening of the raffinate tower, and in addition, the temperature of the reflux tank and the phase state of a desorption agent in the reflux tank are automatically balanced and controlled by a PDV pressure difference control valve. The bottom of the raffinate tower is provided with a discharge hole, and the separated normal paraffin and isoparaffin are discharged from the discharge hole at the bottom of the tower and respectively enter a normal paraffin and isoparaffin re-separation system, so that corresponding series products are obtained. Wherein:
the middle part of the extract tower is provided with a feed inlet which is connected with an extract discharge port of the adsorption tower, the bottom of the extract tower is provided with a discharge port, the middle part of the extract tower is provided with a thermal reflux temperature control system, and the top of the extract tower is provided with a reflux device; the middle part of the raffinate tower is provided with a feed inlet which is connected with a raffinate discharge outlet of the adsorption tower, the bottom of the raffinate tower is provided with a discharge outlet, the middle part of the raffinate tower is provided with a thermal reflux temperature control system, and the top of the raffinate tower is provided with a reflux device; preferably, the number of trays in the draw column and the raffinate column is from 60 to 70, respectively.
The isoparaffin separation system comprises a first isoparaffin separation tower and a second isoparaffin separation tower, wherein a feed inlet of the first isoparaffin separation tower is connected with a tower kettle discharge outlet at the bottom of the raffinate tower, the first isoparaffin separation tower is provided with three discharge outlets, a tower bottom discharge outlet of the first isoparaffin separation tower is connected with a feed inlet of the second isoparaffin separation tower, the second isoparaffin separation tower is used for further separating the heavy isoparaffin from the first isoparaffin separation tower, and the second isoparaffin separation tower is provided with a tower top discharge outlet and a tower bottom discharge outlet.
The normal paraffin separating system comprises a first normal paraffin separating tower, a second normal paraffin separating tower, a third normal paraffin separating tower and a fourth normal paraffin separating tower, wherein a feed inlet of the first isoparaffin separating tower is connected with a discharge outlet of a tower kettle at the bottom of the extract liquid tower, a discharge outlet of the first isoparaffin separating tower is connected with a feed inlet of the second normal paraffin separating tower, a discharge outlet at the bottom of the second normal paraffin separating tower is connected with a feed inlet at the middle part of the third normal paraffin separating tower, and a discharge outlet at the bottom of the third normal paraffin separating tower is connected with a feed inlet at the middle part of the fourth normal paraffin separating tower.
The features and properties of the present invention are described in further detail below with reference to examples.
The molecular sieve feed used in the following examples was: the normal and isomeric alkane composed of specific proportion and carbon number is called.
Example 1
A device for adsorbing oxygen-containing compounds in Fischer-Tropsch paraffin to trace amounts is disclosed, and is shown in figure 1, and comprises a 1-0-light component removal tower, a heavy component removal tower 1-1, a hydrogenation feeding buffer tank 1-2, a hydrogenation and dearomatization reactor 1-3, a stripping tower 1-4, a water cooler 1-5, a reflux tank 1-6, a molecular sieve oxygen-containing compound removal tank 1-7, a molecular sieve feeding buffer tank 1-8, a molecular sieve feeding heater, a fine filter, a rotary valve 1-9, a first adsorption tower 1-10 and a second adsorption tower 1-11.
A bottom discharge port of the light component removal tower 1-0 is connected with a feed port of a side pump of the heavy component removal tower 1-1, a discharge port of the side pump of the heavy component removal tower 1-1 is connected with a feed port of a hydrogenation feed buffer tank 1-2 through a heat exchanger 1-12, an outlet of the bottom of the hydrogenation feed buffer tank 1-2 is connected with a feed port arranged at the bottom of a hydrogenation dearomatization reactor 1-3, a hydrogen buffer tank 1-13 is also arranged on a pipeline which is connected with the feed port arranged at the bottom of the hydrogenation feed buffer tank 1-2 and the bottom of the hydrogenation dearomatization reactor 1-3, a discharge port at the top of the hydrogenation dearomatization reactor 1-3 is connected with a feed port arranged at the middle part of a stripping tower 1-4, a reflux device is arranged at the top of the stripping tower 1-4, and the reflux device is a reflux tank 1-6, the reflux tank 1-6 is connected with the top of a stripping tower 1-4 through a water cooler 1-5, meanwhile, the reflux tank is provided with a light component recycling facility, a discharge port of the reflux tank 1-6 at the top of the stripping tower 1-4 is connected with a feed port of a light component removal tower 1-0, a discharge port at the bottom of the stripping tower 1-4 is connected with a feed port at the bottom of a molecular sieve oxygen-containing compound removal tank 1-7, a corresponding molecular sieve is arranged in the molecular sieve oxygen-containing compound removal tank 1-7, a molecular sieve regeneration system is arranged at the bottom of the tank, a discharge port at the top of the tank is connected with a molecular sieve feed pipeline, and the molecular sieve feed pipeline is connected with a molecular sieve feed buffer tank 1-8; the molecular sieve feeding buffer tanks 1-8 are connected with a molecular sieve adsorption system, the molecular sieve adsorption system comprises first adsorption towers 1-10 and second adsorption towers 1-11, the feeding and discharging of the first adsorption towers 1-10 and the second adsorption towers 1-11 are balanced and controlled by rotary valves 1-9, 5A type molecular sieves are filled in the first adsorption towers 1-10 and the second adsorption towers 1-11, the front sections of the discharge ports of the first adsorption towers 1-10 and the second adsorption towers 1-11 can be provided with raffinate and extract feeding mixers and extract and raffinate flash tanks, and the extract and raffinate enter the discharge ports of the extract and raffinate towers from the extract and raffinate flash tanks, the method is used for adsorbing and separating crude liquid wax obtained by indirect coal liquefaction to obtain extract liquid of high-purity normal paraffin and a desorbent and raffinate of high-purity isoparaffin and the desorbent.
Example 2
An apparatus for separating the extract and raffinate produced by the apparatus shown in example 1 above into their corresponding products, as shown in FIG. 2, mainly comprising rotary valves 1-9, isoparaffin feed buffer tanks 2-1, raffinate towers 2-2, first isoparaffin separation towers 2-3, second isoparaffin separation towers 2-4, third isoparaffin separation towers 2-15, raffinate tower middle reflux streams 2-5, reflux tanks 2-6, normal paraffin feed buffer tanks 2-7, extract towers 2-8, first normal paraffin separation towers 2-9, second normal paraffin separation towers 2-10, third normal paraffin separation towers 2-11, fourth normal paraffin separation towers 2-12, fifth normal paraffin separation towers 2-16, reflux tanks 2-13, and refluxing the middle section of the extract tower for 2-14.
The extract and the raffinate separated by the molecular sieve adsorption system shown in fig. 2 enter from the feed inlets of the extract tower and the raffinate tower respectively, and the extract tower and the raffinate tower are respectively used for separating the desorbent in the extract tower and the raffinate tower to obtain normal paraffin and isoparaffin respectively. The top of the extraction liquid tower 2-8 and the top of the raffinate tower 2-2 are both provided with reflux devices, each reflux device comprises an air cooler (not shown in the figure), a water cooler 2-5 and a reflux tank 2-6 which are connected in sequence, a feed inlet of the air cooler is connected with an outlet at the top of the raffinate tower 2-2, an outlet of the reflux tank 2-6 is connected with an outlet at the top of the raffinate tower 2-2, and in addition, the temperature of the reflux tank and the phase state of a desorption agent in the reflux tank are automatically balanced and controlled by a PDV differential pressure control valve. The bottom of the raffinate tower 2-2 is provided with a discharge hole, the separated normal paraffin and isoparaffin are discharged from the discharge hole at the bottom of the tower and respectively enter a normal paraffin and isoparaffin re-separation system,
the isoparaffin separation system comprises a first isoparaffin separation tower 2-3, a second isoparaffin separation tower 2-4 and a third isoparaffin separation tower 2-15, wherein a feed inlet of the first isoparaffin separation tower 2-3 is connected with a tower kettle discharge outlet at the bottom of the raffinate tower 2-2, the first isoparaffin separation tower 2-3 is provided with three discharge outlets in total, a tower bottom discharge outlet and a tower top discharge outlet of the first isoparaffin separation tower 2-3 are respectively connected with a feed inlet of the second isoparaffin separation tower 2-4 and a feed inlet of the third isoparaffin separation tower 2-15, the second isoparaffin separation tower 2-4 is used for further separating heavy isoparaffin from the first isoparaffin separation tower 2-3, and the third isoparaffin separation tower 2-15 is used for further separating heavy isoparaffin from the first isoparaffin separation tower 2-3, the second isoparaffin separator 2-4 is provided with a top discharge hole and a bottom discharge hole, and the third isoparaffin separator 2-15 is provided with a top discharge hole and a bottom discharge hole.
The normal paraffin separating system comprises a first normal paraffin separating tower 2-9, a second normal paraffin separating tower 2-10, a third normal paraffin separating tower 2-11, a fourth normal paraffin separating tower 2-12 and a fifth normal paraffin separating tower 2-16, the feed inlet of the first isoparaffin knockout tower 2-9 links with the bottom of the extract liquid tower 2-8 tower cauldron discharge ports, the first isoparaffin knockout tower 2-9 top of the tower discharge port, the bottom of the tower discharge port links with the feed inlet of the second normal paraffin knockout tower 2-10, the feed inlet of the fifth normal paraffin knockout tower 2-16 separately, the second normal paraffin knockout tower 2-10 bottom of the tower discharge port links with the feed inlet of the third normal paraffin knockout tower 2-11 middle part, the third normal paraffin knockout tower 2-11 bottom of the tower discharge port links with the feed inlet of the fourth normal paraffin knockout tower 2-12 middle part.
Example 3
A device for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace content is disclosed, and simultaneously referring to a figure 1 and a figure 2, the device mainly comprises a de-weighting tower 1-1, a hydrogenation feeding buffer tank 1-2, a hydrogenation de-aromatization reactor 1-3, a stripping tower 1-4, a water cooler 1-5, a reflux tank 1-6, a molecular sieve de-oxygenated compound tank 1-7, a molecular sieve feeding buffer tank 1-8, a molecular sieve feeding heater, a fine filter, a rotary valve 1-9, a first adsorption tower 1-10 and a second adsorption tower 1-11; the system comprises, by weight, 2-1 parts of an isoparaffin feeding buffer tank, 2-2 parts of a raffinate tower, 2-3 parts of a first isoparaffin separation tower, 2-4 parts of a second isoparaffin separation tower, 2-5 parts of middle-section reflux of the raffinate tower, 2-6 parts of a reflux tank, 2-7 parts of a normal paraffin feeding buffer tank, 2-8 parts of an extract tower, 2-9 parts of a first normal paraffin separation tower, 2-10 parts of a second normal paraffin separation tower, 2-11 parts of a third normal paraffin separation tower, 2-12 parts of a fourth normal paraffin separation tower, 2-13 parts of a reflux tank and 2-14 parts of middle-section reflux of the extract tower.
Referring to FIG. 1, a bottom discharge port of a lightness-removing column 1-0 is connected with a feed port of a side pump of a heaving column 1-1, a discharge port of the side pump of the heaving column 1-1 is connected with a feed port of a hydrogenation feed buffer tank 1-2 through a heat exchanger 1-12, an outlet at the bottom of the hydrogenation feed buffer tank 1-2 is connected with a feed port at the bottom of a hydrogenation dearomatization reactor 1-3, a hydrogen buffer tank 1-13 is arranged on a pipeline which is connected with the feed port at the bottom of the hydrogenation feed buffer tank 1-2 and the feed port at the bottom of the hydrogenation dearomatization reactor 1-3, a discharge port at the top of the hydrogenation dearomatization reactor 1-3 is connected with a feed port at the middle part of a stripping column 1-4, a reflux device is arranged at the top of the stripping column 1-4, the reflux device is a reflux tank 1-6, the reflux tank 1-6 is connected with the top of a stripping tower 1-4 through a water cooler 1-5, meanwhile, the reflux tank is provided with a light component recycling facility, a discharge port of the reflux tank 1-6 at the top of the stripping tower 1-4 is connected with a feed port of a light component removal tower 1-0, a discharge port at the bottom of the stripping tower 1-4 is connected with a feed port at the bottom of a molecular sieve oxygen-containing compound removal tank 1-7, a corresponding molecular sieve is arranged in the molecular sieve oxygen-containing compound removal tank 1-7, a molecular sieve regeneration system is arranged at the bottom of the tank, a discharge port at the top of the tank is connected with a molecular sieve feed pipeline, and the molecular sieve feed pipeline is connected with a molecular sieve feed buffer tank 1-8; the molecular sieve feeding buffer tanks 1-8 are connected with a molecular sieve adsorption system, the molecular sieve adsorption system comprises first adsorption towers 1-10 and second adsorption towers 1-11, the feeding and discharging of the first adsorption towers 1-10 and the second adsorption towers 1-11 are balanced and controlled by rotary valves 1-9, 5A type molecular sieves are filled in the first adsorption towers 1-10 and the second adsorption towers 1-11, the front sections of the discharge ports of the first adsorption towers 1-10 and the second adsorption towers 1-11 can be provided with raffinate and extract feeding mixers and extract and raffinate flash tanks, and the extract and raffinate enter the discharge ports of the extract and raffinate towers from the extract and raffinate flash tanks, the method is used for adsorbing and separating crude liquid wax obtained by indirect coal liquefaction to obtain extract liquid of high-purity normal paraffin and a desorbent and raffinate of high-purity isoparaffin and the desorbent.
Then referring to fig. 2, the extract and the raffinate separated by the molecular sieve adsorption system shown in fig. 1 enter from the feed inlets of the extract tower and the raffinate tower respectively, and the extract tower and the raffinate tower are respectively used for separating the desorbent from the extract tower and the raffinate tower to obtain n-alkane and isoparaffin respectively. The top of the extraction liquid tower 2-8 and the top of the raffinate tower 2-2 are both provided with reflux devices, each reflux device comprises an air cooler (not shown in the figure), a water cooler 2-5 and a reflux tank 2-6 which are connected in sequence, a feed inlet of the air cooler is connected with an outlet at the top of the raffinate tower 2-2, an outlet of the reflux tank 2-6 is connected with an outlet at the top of the raffinate tower 2-2, and in addition, the temperature of the reflux tank and the phase state of a desorption agent in the reflux tank are automatically balanced and controlled by a PDV differential pressure control valve. The bottom of the raffinate tower 2-2 is provided with a discharge hole, the separated normal paraffin and isoparaffin are discharged from the discharge hole at the bottom of the tower and respectively enter a normal paraffin and isoparaffin re-separation system,
the isoparaffin separation system comprises a first isoparaffin separation tower 2-3, a second isoparaffin separation tower 2-4 and a third isoparaffin separation tower 2-15, wherein a feed inlet of the first isoparaffin separation tower 2-3 is connected with a tower kettle discharge outlet at the bottom of a raffinate tower 2-2, the first isoparaffin separation tower 2-3 is provided with three discharge outlets in total, a tower bottom discharge outlet and a tower top discharge outlet of the first isoparaffin separation tower 2-3 are respectively connected with a feed inlet of the second isoparaffin separation tower 2-4 and a feed inlet of the third isoparaffin separation tower 2-15, the second isoparaffin separation tower 2-4 is used for further separating the heavy isoparaffin from the first isoparaffin separation tower 2-3, and the third isoparaffin separation tower 2-15 is used for further separating the heavy isoparaffin from the first isoparaffin separation tower 2-3, the second isoparaffin separator 2-4 is provided with a top discharge hole and a bottom discharge hole, and the third isoparaffin separator 2-15 is provided with a top discharge hole and a bottom discharge hole.
The normal paraffin separating system comprises a first normal paraffin separating tower 2-9, a second normal paraffin separating tower 2-10, a third normal paraffin separating tower 2-11, a fourth normal paraffin separating tower 2-12 and a fifth normal paraffin separating tower 2-16, the feed inlet of the first isoparaffin knockout tower 2-9 links with the bottom of the extract liquid tower 2-8 tower cauldron discharge ports, the first isoparaffin knockout tower 2-9 top of the tower discharge port, the bottom of the tower discharge port links with the feed inlet of the second normal paraffin knockout tower 2-10, the feed inlet of the fifth normal paraffin knockout tower 2-16 separately, the second normal paraffin knockout tower 2-10 bottom of the tower discharge port links with the feed inlet of the third normal paraffin knockout tower 2-11 middle part, the third normal paraffin knockout tower 2-11 bottom of the tower discharge port links with the feed inlet of the fourth normal paraffin knockout tower 2-12 middle part.
Example 4
A method for reducing the content of aromatic hydrocarbon in Fischer-Tropsch paraffin to trace content comprises the following process flows:
referring first to the apparatus shown in fig. 1, the apparatus shown in fig. 1 can be used to adsorb the oxygen-containing compounds in the fischer-tropsch alkane to trace amounts, specifically: the molecular sieve feed separated from the middle section of the heavy component removal tower 1-1 is subjected to heat exchange through a feed/reaction product heat exchanger and a feed/heat conduction oil heat exchanger to 150-200 ℃, enters a hydrogenation feed buffer tank 1-2, is pressurized to 2.4-2.6Mpa through a hydrogenation feed pump, enters a hydrogenation dearomatization reactor 1-3 after mixed hydrogen, and enters a stripping tower 1-4 after the reaction product is subjected to heat exchange through the feed/reaction product heat exchanger.
The gas at the top of the stripping tower 1-4 is condensed and cooled by a condenser at the top of the stripping tower 1-4 and then enters a reflux tank at the top of the stripping tower 1-4. The stripping tower 1-4 adopts a total reflux mode. Part of cracked hydrocarbons generated in the stripping tower 1-4 return to the light component removal tower 1-0 through a discharge hole of a reflux tank 1-6 at the top, a heat exchanger 1-12 arranged on a pipeline connecting the stripping tower 1-4 and a molecular sieve oxygen compound removal tank 1-7 is used for returning residual heat generated in the heavy component removal tower to a hydrogenation feeding buffer tank 1-2 to heat hydrogen in the hydrogen, the discharge of the stripping tower 1-4 is pressurized by a tower bottom pump of the stripping tower 1-4 and then is pumped into the molecular sieve oxygen compound removal tank 1-7, oxygen compounds and aromatic hydrocarbons are adsorbed in a full liquid phase under the working condition of 0.3-0.7MPA at 40-120 ℃, and the adsorption is completed to the molecular sieve feeding buffer tank 1-8.
The molecular sieve material for dearomatizing and removing oxygen-containing compounds in the molecular sieve feeding buffer tank 1-8 is pressurized by a molecular sieve material pump, passes through a heat exchanger, a fine filter and a rotary valve and is sent to an adsorption tower (consisting of a first adsorption tower 1-10 and a second adsorption tower 1-11), the feeding and discharging of the first adsorption tower 1-10 and the second adsorption tower 1-11 are balanced and controlled by a rotary valve 1-9, 5A type molecular sieves are filled in the first adsorption tower 1-10 and the second adsorption tower 1-11 and are used for adsorbing and separating crude liquid wax obtained by indirect liquefaction of coal under the working conditions of temperature of 170-.
Referring again to fig. 2, the extract and raffinate separated by the apparatus shown in fig. 1 may be separated again by the apparatus shown in fig. 1 to obtain corresponding series of products, specifically: the extract and raffinate separated by the molecular sieve adsorption system enter through respective buffer tanks from respective feed inlets of an extract tower 2-8 and a raffinate tower 2-2, a discharge outlet at the bottom of the raffinate tower 2-2 is connected with an isoparaffin separation system, and a discharge outlet at the bottom of the extract tower 2-8 is connected with a normal paraffin separation system.
The isoparaffin separation system comprises a first isoparaffin separation tower 2-3 and a second isoparaffin separation tower 2-4, which are used for rectifying isoparaffin to separate isoparaffin with different brands, wherein a feed inlet of the first isoparaffin separation tower 2-3 is connected with a discharge outlet at the bottom of a raffinate tower 2-2, the first isoparaffin separation tower 2-3 is provided with three discharge outlets, IP40 isoparaffin is output from a discharge outlet at the top of the tower, IP60 isoparaffin is output from the middle of the tower, and heavy isoparaffin is output from a discharge outlet at the bottom of the tower.
The bottom discharge port of the first isoparaffin separation tower 2-3 is connected with the feed port of the second isoparaffin separation tower 2-4, the second isoparaffin separation tower 2-4 is used for further separating the heavy isoparaffin from the first isoparaffin separation tower 2-3, the second isoparaffin separation tower 2-4 is provided with a top discharge port and a bottom discharge port, the top discharge port outputs IP80 isoparaffin, the bottom discharge port outputs IP95 isoparaffin, and the top discharge port of the third isoparaffin separation tower 2-15 outputs IP40L and bottom output IP 40H.
The normal paraffin separating system comprises a first normal paraffin separating tower 2-9, a second normal paraffin separating tower 2-10, a third normal paraffin separating tower 2-11 and a fourth normal paraffin separating tower 2-12, and is used for normal paraffin rectification to separate different series of liquid wax, a feed inlet of the first normal paraffin separating tower 2-9 is connected with a tower kettle discharge outlet at the bottom of a liquid extracting tower 2-8, a tower top discharge outlet of the first normal paraffin separating tower 2-9 outputs light liquid paraffin components, and a tower bottom discharge outlet outputs heavy liquid paraffin products.
The top discharge port of the first n-alkane separating tower 2-9 is connected with the feed port of the second n-alkane separating tower 2-10, the second n-alkane separating tower 2-10 is used for further separating the light liquid paraffin component from the first n-alkane separating tower 2-9, the second n-alkane separating tower 2-10 is provided with a top discharge port and a bottom discharge port, the top discharge port outputs product monomer wax NC10, and the bottom discharge port outputs NC10-NC13 component to enter the third n-alkane separating tower 2-11. The third n-alkane separating tower 2-11 is provided with a tower top discharge hole and a tower bottom discharge hole, the tower top discharge hole outputs NC10-NC12 components, the tower bottom discharge hole outputs NC12-NC13 components, and the components enter the fourth n-alkane separating tower 2-12. The fourth n-alkane separation tower 2-12 is provided with a tower top discharge hole and a tower bottom discharge hole, the tower top discharge hole outputs product monomer wax NC12, the tower bottom discharge hole outputs NC12-NC13 components, the tower top discharge hole outputs NC10-NC12 components of the third n-alkane separation tower 2-11, the components are mixed and output to produce light liquid paraffin products with specific composition content, and the tower top discharge hole of the fifth n-alkane separation tower 2-16 outputs NC14 components and tower bottom output NC15 components.
In summary, the embodiment of the invention provides a device and a method for reducing the content of aromatic hydrocarbons in fischer-tropsch alkanes to trace, a hydrodearomatization reactor and a molecular sieve oxygen compound removal system are arranged in front of a molecular sieve adsorption system, so that the content of aromatic hydrocarbons and oxygen compounds in isoparaffin can be effectively reduced, then different products in normal paraffin and isoparaffin separation systems are used for separating different products in normal paraffin and isoparaffin, so that normal paraffin and isoparaffin can be used as various environment-friendly solvents and environment-friendly additives, and the product quality and the application range are greatly improved. The experimental result shows that the device can reduce the content of aromatic hydrocarbon to below 5ppm, reduce the content of oxygen-containing compounds to below 2ppm and reduce the content purity of single components to not less than 98.5%.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An apparatus for reducing the content of aromatics in fischer-tropsch alkanes to trace amounts, the apparatus comprising: the system mainly comprises a molecular sieve adsorption system and a normal paraffin and isoparaffin separation system, wherein the molecular sieve adsorption system mainly comprises: the device comprises a light component removing tower, a heavy component removing tower, a hydrogenation feeding buffer tank, a hydrogenation dearomatization reactor, a stripping tower, a molecular sieve oxygen-containing compound removing tank and an adsorption tower, wherein a discharge port of the light component removing tower is connected with a feed port of the heavy component removing tower, a discharge port of the heavy component removing tower is connected with a feed port of the hydrogenation feeding buffer tank, a discharge port of the hydrogenation feeding buffer tank is connected with a feed port of the hydrogenation dearomatization reactor, a discharge port of the hydrogenation dearomatization reactor is connected with a feed port of the stripping tower, a discharge port of the stripping tower is connected with a feed port of the molecular sieve oxygen-containing compound removing tank, a discharge port of the molecular sieve oxygen-containing compound removing tank is connected with a feed port of the adsorption tower, and a discharge port of extract liquid and a discharge port of raffinate are arranged on the adsorption tower; and an extract liquid discharge port and a raffinate liquid discharge port of the adsorption tower are connected with an extract liquid feed port and a raffinate liquid feed port of the normal paraffin and isoparaffin separation systems, and the extract liquid and the raffinate liquid are respectively separated in the normal paraffin and isoparaffin separation systems.
2. The apparatus for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin hydrocarbons to a trace amount according to claim 1, wherein the normal and isoparaffin separation systems comprise an extract tower, a raffinate tower, a normal paraffin separation system and an isoparaffin separation system, an extract outlet of the molecular sieve adsorption system is connected with an inlet of the extract tower of the normal paraffin separation system, and a raffinate outlet of the molecular sieve adsorption system is connected with an inlet of the raffinate tower of the isoparaffin separation system; the discharge hole of the extract liquid tower and the discharge hole of the raffinate tower are respectively connected with the normal paraffin separation system and the isoparaffin separation system to carry out the re-separation of normal paraffin and isoparaffin.
3. The device for reducing the content of aromatic hydrocarbons in Fischer-Tropsch paraffins according to claim 1, wherein a heat exchanger is further sequentially arranged between the discharge port of the de-heavy column side pump and the hydrogenation feed buffer tank;
preferably, a first heat exchanger and a second heat exchanger are sequentially arranged between the discharge hole of the de-heavy column side-draw pump and the hydrogenation feed buffer tank;
preferably, a feed port of the first heat exchanger is connected with a discharge port of the de-heavy column side pump, a discharge port of the first heat exchanger is connected with a feed port of the second heat exchanger, and a discharge port of the second heat exchanger is connected with a feed port of the hydrogenation feed buffer tank;
preferably, the first heat exchanger is a heat exchanger for exchanging heat between the feeding material and the reaction products, and the second heat exchanger is a heat exchanger for exchanging heat between the feeding material and the low-temperature hot oil.
4. The device for reducing the content of aromatic hydrocarbons in Fischer-Tropsch paraffins to a trace amount according to claim 1, wherein a reflux tank is arranged at the top of the stripping tower, a discharge port of the reflux tank is connected with a feed port of the light component removal tower, and a discharge port of the bottom of the stripping tower is connected with a feed port of the molecular sieve oxygen compound removal tank;
preferably, a hydrogen buffer tank is arranged between the hydrogenation feeding buffer tank and the hydrogenation dearomatization reactor;
preferably, the molecular sieve oxygen-containing compound removing tank is internally provided with a molecular sieve, the tank bottom is provided with a molecular sieve regeneration system, and the tank top is provided with a discharge hole which is connected with a molecular sieve feeding pipeline;
preferably, the molecular sieve oxygen-containing compound removing tank is connected with a molecular sieve feeding buffer tank through a molecular sieve feeding pipeline, and the molecular sieve feeding buffer tank is connected with a feeding hole at the bottom of the adsorption tower.
5. The apparatus for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin hydrocarbon according to claim 2, wherein the extract outlet and the raffinate outlet of the adsorption tower on the molecular sieve adsorption system are connected with the extract inlet and the raffinate inlet of the normal and isoparaffin separation system,
preferably, the adsorption tower comprises a first adsorption tower and a second adsorption tower, and molecular sieves are arranged in the first adsorption tower and the second adsorption tower;
preferably, a rotary valve is connected between the first adsorption tower and the second adsorption tower, and the rotary valve is used for balancing and controlling feeding and discharging of the first adsorption tower and the second adsorption tower;
preferably, the reflux devices at the tops of the extract tower and the raffinate tower comprise an air cooler, a water cooler and a raffinate tower reflux tank;
preferably, the front sections of the feed inlets of the extract tower and the raffinate tower are also provided with a normal alkane feed buffer tank and an isoparaffin feed buffer tank;
preferably, the number of trays in the draw column and the raffinate column is from 60 to 70.
6. The apparatus of claim 2, wherein the isoparaffin separation system comprises a first isoparaffin separation column, a second isoparaffin separation column, and a third isoparaffin separation column, and the outlet of the raffinate column is connected to the inlet of the first isoparaffin separation column, the outlet of the first isoparaffin separation column is connected to the inlet of the third isoparaffin separation column, the outlet of the first isoparaffin separation column is connected to the inlet of the second isoparaffin separation column, the outlet of the third isoparaffin separation column is provided with an outlet of the top column and an outlet of the bottom column, and the second isoparaffin separation column is provided with an outlet of the top column and an outlet of the bottom column.
7. The apparatus according to claim 2, wherein the normal paraffin separation system comprises a first normal paraffin separation tower, a second normal paraffin separation tower, a third normal paraffin separation tower, a fourth normal paraffin separation tower and a fifth normal paraffin separation tower, and a tower bottom outlet of the extract tower is connected to the inlet of the first normal isoparaffin separation tower, a tower top outlet of the first normal paraffin separation tower is connected to the inlet of the second normal paraffin separation tower, a tower bottom outlet of the first normal paraffin separation tower is connected to the inlet of the fifth normal paraffin separation tower, a tower bottom outlet of the second normal paraffin separation tower is connected to the inlet of the third normal paraffin separation tower, and a tower bottom outlet of the third normal paraffin separation tower is connected to the inlet of the fourth normal paraffin separation tower, the fourth normal paraffin separation tower is provided with a tower top discharge hole and a tower bottom discharge hole, and the fifth normal paraffin separation tower is provided with a tower top discharge hole and a tower bottom discharge hole.
8. A process for reducing to trace amounts the aromatic content of Fischer-Tropsch alkanes, using the apparatus according to any one of claims 1 to 7, comprising the steps of: removing oxygen-containing compounds and aromatic hydrocarbons in Fischer-Tropsch paraffin by using a molecular sieve adsorption system to obtain extract liquid and raffinate, and separating the extract liquid and the raffinate by using a normal paraffin and isoparaffin separation system to obtain corresponding normal paraffin products and isoparaffin products.
9. The method of claim 8, wherein the step of removing oxygenates and aromatics from the fischer-tropsch alkanes using a molecular sieve adsorption system comprises the steps of: inputting Fischer-Tropsch paraffin into the light component removal tower to remove light components, then inputting the Fischer-Tropsch paraffin into the heavy component removal tower to remove light components and heavy components, and obtaining normal and isoparaffin molecular sieve materials with specific proportion and carbon number; then the molecular sieve material is conveyed to a hydrogenation feeding buffer tank, is pressurized by a hydrogenation feeding pump and then is mixed with hydrogen in proportion, and then enters a hydrogenation dearomatization reactor for hydrogenation dearomatization reaction, and then is conveyed to a stripping tower to flash and remove dissolved hydrogen which does not participate in the reaction, and simultaneously cracked hydrocarbons in the stripping tower are returned to the light component removal tower; inputting the mixture into the molecular sieve oxygen-containing compound removal tank to adsorb and remove oxygen-containing compounds and aromatic compounds, and then conveying the mixture to the adsorption tower to separate normal paraffin and isoparaffin to obtain extract liquid of high-purity normal paraffin and desorbent and raffinate of high-purity isoparaffin and desorbent;
preferably, the Fischer-Tropsch paraffin is subjected to heat exchange by a heat exchanger to 150 ℃ and 200 ℃, and then enters the hydrogenation feed buffer tank;
preferably, the reaction conditions in the hydrodearomatization reactor are as follows: pressurizing the Fischer-Tropsch paraffin by a hydrogenation feed pump, then feeding mixed hydrogen into the hydrogenation dearomatization reactor, carrying out hydrogenation dearomatization reaction under the conditions of 2.4-2.6Mpa and 225-240 ℃ under the action of a hydrogenation catalyst, and carrying out hydrogenation catalytic reaction to convert aromatic compounds in the Fischer-Tropsch paraffin into naphthenic hydrocarbons through hydrogenation saturation so as to reduce the aromatic hydrocarbon content in the Fischer-Tropsch paraffin;
preferably, the reaction conditions in the molecular sieve oxygen compound removing tank are as follows: a 13X-type molecular sieve is arranged in the molecular sieve oxygen-containing compound removing tank, and oxygen-containing compounds and aromatic hydrocarbons in Fischer-Tropsch paraffin are adsorbed in a full liquid phase under the working conditions of 40-120 ℃ and 0.3-0.7MPA, so that the content of the oxygen-containing compounds is reduced and the content of the aromatic hydrocarbons is reduced again;
preferably, the reaction conditions in the adsorption column are: the adsorption tower is filled with a 5A type molecular sieve and is used for adsorbing and separating crude liquid wax obtained by indirect liquefaction of coal under the working conditions of temperature of 170-.
10. The process of claim 8, wherein the separation of the extract and the raffinate using the n-paraffin and isoparaffin separation system comprises the steps of: separating the molecular sieve adsorption system to obtain extract liquid of high-purity normal paraffin and a desorbent and raffinate of high-purity isoparaffin and the desorbent, inputting the extract liquid and the raffinate into a normal paraffin and isoparaffin separation system for separation to obtain corresponding series of products;
preferably, the raffinate enters the first isoparaffin tower from the bottom of the raffinate to be separated, the top discharge port of the first isoparaffin separation tower outputs IP40 isoparaffin and IP60 isoparaffin, the top discharge port of the second isoparaffin separation tower outputs IP80 isoparaffin, the bottom discharge port outputs IP95 isoparaffin, the top discharge port of the third isoparaffin separation tower outputs IP40L isoparaffin, and the bottom discharge port outputs IP40H isoparaffin;
preferably, the tower top feed opening of the first n-isoparaffin separation tower outputs a light liquid paraffin component, the tower bottom feed opening outputs a heavy liquid paraffin product, the tower top feed opening of the second n-paraffin separation tower outputs product monomer wax NC10, the tower bottom feed opening outputs NC10-NC13 components to enter a third n-paraffin separation tower, the tower top feed opening of the third n-paraffin separation tower outputs NC10-NC12 components, the tower bottom feed opening outputs NC12-NC13 components, the tower top feed opening of the fourth n-paraffin separation tower outputs product monomer wax NC12, the tower bottom feed opening outputs NC12-NC13 components, the tower top feed opening of the fourth n-paraffin separation tower outputs NC12-NC13 components and the tower top feed opening of the third n-paraffin separation tower outputs NC10-NC12 components to be mixed with each other to output light liquid paraffin products with specific component contents, and a discharge port at the top of the fifth normal paraffin separation tower outputs an NC14 component, and a discharge port at the bottom of the fifth normal paraffin separation tower outputs an NC15 component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210439881.1A CN114736712A (en) | 2022-04-25 | 2022-04-25 | Device and method for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin to trace amount |
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| CN202210439881.1A CN114736712A (en) | 2022-04-25 | 2022-04-25 | Device and method for reducing aromatic hydrocarbon content in Fischer-Tropsch paraffin to trace amount |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505418A (en) * | 2022-10-21 | 2022-12-23 | 中国石油化工股份有限公司 | A method for removing oxygen-containing compounds in isoparaffins |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505418A (en) * | 2022-10-21 | 2022-12-23 | 中国石油化工股份有限公司 | A method for removing oxygen-containing compounds in isoparaffins |
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