CN111939849A - A thiophene production recycling system - Google Patents

Abstract

The invention discloses a thiophene production cycle recycling system. Two mixers are arranged on the reaction pipeline before and after, the butadiene inlet pipeline is communicated with the side of the first production mixer, and the sulfur inlet pipeline is divided into two branches. , respectively communicated with the tops of the first production mixer and the second production mixer, and the gas-liquid outlet is located below the second production mixer; the tar separator is provided with a heat exchanger assembly; the gas outlet from the tar separator The gas-liquid mixture from the top of the condenser enters the condenser, and the thiophene is separated from the outlet of the condenser; the gas-liquid mixture after being processed by the condenser enters two pressure-cooling processors in turn; comes out from the second pressure-cooling processor The liquefied gas is circulated to the butadiene inlet pipe through the pipeline, and the hydrogen sulfide gas from the top enters the hydrogen sulfide recovery station. The purpose of the present invention is to provide a production system that can effectively reduce the production of tar in the reaction system, improve the yield of thiophene, and effectively treat other hydrogen components and heavy components.

Description

A thiophene production recycling system

technical field

The invention relates to chemical production equipment, in particular to a thiophene production cycle recycling system.

Background technique

Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom. Systematic name 1-thia-2,4-cyclopentadiene. From the structural point of view, thiophene is a heterocyclic compound and a thioether. Molecular formula C4H4S, molecular weight 84.14. Melting point -38 ℃, boiling point 84 ℃, density 1.051g/cm3. At room temperature, thiophene is a colorless, foul-smelling, tear-inducing liquid. Thiophene occurs naturally in petroleum, in concentrations as high as several percent. Industrially, it is used for the denaturation of ethyl alcohols. Like furans, thiophenes are aromatic. One of the two pairs of lone electrons in the sulfur atom is conjugated with two double bonds, forming a delocalized Π bond. Thiophene is only slightly less aromatic than benzene. Natural thiophene mainly exists in coal tar and shale oil, and the coking crude benzene contains about 0.5% of thiophene. The early thiophene products were all separated from crude benzene, and the purity was very low, generally about 98%. Thiophene is aromatic and can be used as a raw material for the production of fuels and plastics instead of benzene. Since thiophene is more active and easier to metabolize in animals, thiophene is given a more special purpose in the pharmaceutical industry. Mainly used in the synthesis of thiophene pyridine, thiophene diamine, cephalosporin and so on. Thiophene is an industrial solvent with good performance. In medicine, many thiophene derivatives with various pharmacological activities have been gradually discovered by humans, and thiophene derivatives are gradually replacing some benzene derivatives. In agriculture, sulfonylurea derivatives of thiophene are new herbicides with high efficiency and low toxicity. Thiophene can also be used as a synthetic raw material for pesticides, fungicides, biological growth promoters and other agents.

As an important basic chemical product, thiophene is widely used in the chemical and pharmaceutical industries, and has a wide market and good economic benefits. According to incomplete statistics, the world produces and consumes about 8,000 tons of thiophene and its derivatives every year. Among them, the main areas of consumption are pharmaceutical synthesis, pesticide synthesis, dye synthesis, and β-thiophene derivatives are also used in fragrance synthesis.

Thiophene was first extracted from the pickling solution of the benzene fraction of coal tar, but its separation process is complicated, and a large amount of sulfuric acid is used in the production process, which causes serious corrosion to equipment; not only is the production cost extremely high, but the product quality is poor and the purity is low. The content of thiophene is only 95%-98%, which contains benzene which is difficult to separate, which cannot meet the requirements of the pharmaceutical industry for raw materials. Due to the above problems, this method has been eliminated and replaced by chemical synthesis process.

There are four main chemical synthesis processes of thiophene: butane-hydrogen sulfide process (Socony-Vacuum method), furan-hydrogen sulfide process, butane-sulfur process, and C4 compound-carbon disulfide process.

The butane-hydrogen sulfide process (Socony-Vacuum method) takes butane and hydrogen sulfide as raw materials, and cyclizes thiophene at 600°C without catalyst, and the yield is about 40%. Several variant processes including sulfur or pyrite instead of hydrogen sulfide for reaction are the earliest chemical synthesis of thiophene in foreign countries.

At the same time, butane (or mixed C4) is an inexpensive refinery by-product, and hydrogen sulfide is an acid refinery waste gas. Used to synthesize thiophene, it belongs to waste recycling, and the price of raw materials is low. However, this method has the defects of low yield, strong corrosiveness, large pollution, and difficult treatment of thiophene tar. It has been eliminated abroad in the 1950s.

The furan-hydrogen sulfide process uses furan and hydrogen sulfide as raw materials, and at 300-400 ℃, the metal oxide treated with heteropoly acid is used as a catalyst for gas-phase reaction to obtain thiophene, and methylfuran can be used instead of furan to prepare methylfuran. base thiophene. This process has high product quality, good yield, long catalyst life and does not require regeneration, but furan is expensive, the production site needs hydrogen sulfide resources, and the cost of raw materials is high, so it has been abandoned at present.

The butane-sulfur process is a continuous reaction method of butane and sulfur at a high temperature of 600°C without catalyst, without external heating, and generates thiophene in high yield. The yield is about 40% based on butane, while producing a large amount of thiophene tar with a strong odor. This process has shortcomings such as strong corrosiveness, high pollution, and difficulty in processing thiophene tar. This process has been eliminated in foreign countries in the 1950s.

The C4 compound-carbon disulfide process uses alkali-treated metal oxide as a catalyst, and in a fixed-bed reactor, butane and carbon disulfide react at high temperature to close the ring to synthesize thiophene. Using carbon disulfide as the sulfur source, the reaction generates methane and carbon dioxide. This process not only solves the shortcomings of the original Socony-Vacuum method of low yield and large environmental pollution, but also the price of C4 compounds and carbon disulfide is cheap, and is currently the most important production method abroad.

At present, the butadiene-sulfur process is mainly used to synthesize thiophene in China. This process was first seen in DuPont’s patent (US 2410401), in which, butadiene and sulfur reacted in the gas phase and high temperature to synthesize thiophene, but the reaction would generate coke, which easily caused blockage of pipes and condensers, resulting in the failure of the reaction. Continue; the patent applied by Japan Steel Chemical Co., Ltd. (Public Patent Publication Sho 54-76574) solves the problem of reaction coke accumulation in DuPont's patent. Diene and sulfur are reacted at 420-470 DEG C and normal pressure, and the continuous reaction time can last for more than 14 days. However, because the unreacted sulfur blocks the pipes and condensers after the reaction product is cooled, and the thiophene in the tail gas cannot be recovered well, the above-mentioned patent cannot be industrialized. Due to the relatively low boiling point of thiophene, a large amount of thiophene is entrained in the reaction by-product gas hydrogen sulfide and discharged from the exhaust gas. It is impossible to completely cool the thiophene in it by relying only on the water condenser. However, in order to prevent the blockage of the freezer, a multi-stage cooling And increase the cooling area to solve this problem.

Chinese patent application (publication number CN 1335313 A and CN 1420116 A) discloses the production process and equipment for synthesizing thiophene from butadiene-sulfur, the reaction is the same as the method of the Japanese patent, but the reaction yield is not high and the production cost is relatively large. Patent CN 101654449 B reported that the process was improved, and a high-purity, high-yield, low-energy-consumption, non-polluting production process and device for synthesizing thiophene from butadiene and sulfur were proposed. to the effect of the patent statement. There are two reasons: first, the molar ratio of sulfur and butadiene is too large, and second, the mixing effect of sulfur gas stream and butadiene gas stream is very poor.

Since the molecular form and composition of sulfur are closely related to the temperature, as in the document Guangdong Chemical Industry, 2009, No. 7, page 97, ordinary sulfur exists in the form of S ₈ ring structure at room temperature, and its melting point is 159 ° C. When the temperature rises, the state of sulfur changes from solid to liquid, and the ring structure begins to break. When the temperature rises above 444.6 °C, the liquid sulfur gasifies, and the sulfur element will be in the form of S ₈ , S ₆ , S ₄ , S ₂ these molecules The forms are mixed and coexisted, and the temperature is higher than 750 ℃, and the S ₂ molecular form will mainly exist. Only when the temperature is above 1000 ℃, the sulfur element will exist in the S ₂ molecular form.

Since the molecular form of sulfur is closely related to temperature, it is difficult to write the chemical equation of butadiene and sulfur to express its true reflection. In order not to deviate from the research object expressed in the technical scheme, the elemental form of sulfur will replace the form of sulfur molecules with the form of sulfur atoms. This substitution behavior is relatively common in textbooks. For example, when chemical reactions are expressed in chemical equations, zinc atoms are used to replace zinc molecules. Sodium atoms replace sodium molecules. The chemical equation for the reaction of butadiene and elemental sulfur can be expressed as follows:

Studies have shown that applications with high practical value can only be obtained if the ratio of substances in the chemical equation is close to, otherwise, the cost will be high. Sulfur and oxygen belong to the same family, and their chemical properties are very similar. Excess oxygen reacts with organics to produce carbon dioxide and water. Similarly, excess sulfur reacts with organics to produce carbon disulfide and hydrogen sulfide, while yellow sulfide and organics react easily to dehydrogenation. , the presence of sulfur in excess of the stoichiometric amount can easily carbonize organic matter and form tar. In the patent document CN101654449B, the molar mass ratio of the sulfur atom molecule and the butadiene molecule is both adopted as 3. Practice has proved that as long as the molar ratio of the sulfur atom and the butadiene molecule exceeds 2.5, the yield of the reaction product thiophene is not as good as 2.5. 50%, the amount of tar produced in the production process is too large, and the tar in the reactor is often blocked, and the tar needs to be cleaned up within seven days of continuous production.

The large tar yield in the thiophene production process is caused by the high proportion of sulfur. The direct reason for using excess sulfur for the reaction is that the sulfur and butadiene are not well mixed evenly at the initial stage of the reaction, resulting in incomplete butadiene reaction.

During the reaction, 2,5-dihydrothiophene is formed, indicating that this reaction process is carried out in two steps, and the equation is as follows:

According to the above reaction, it is carried out in two steps, so it is more reasonable and feasible to add sulfur to the reaction system in two steps. Reduce the amount of sulfur used and reduce the generation of tar in the reaction system.

In addition, other substances produced at the same time as thiophene need to be further recycled to avoid the release of harmful substances to the environment. If the hydrogen sulfide generated from the tail gas is released into the environment, it will cause environmental pollution. If it is further recycled, it is environmentally friendly and energy-saving.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a production recycling system that effectively reduces the production of tar in the reaction system, improves the yield of thiophene, and effectively handles other hydrogen components and heavy components.

In order to achieve the above object, the present invention is realized by the following technical solutions:

A thiophene production system, comprising:

Mixer, two mixers are arranged on the reaction pipeline before and after, which are the first production mixer and the second production mixer, respectively, the butadiene inlet pipeline is communicated with the side of the first production mixer, and the sulfur inlet is The pipeline is divided into two branches, which are respectively communicated with the tops of the first production mixer and the second production mixer, and the gas-liquid outlet is arranged below the second production mixer;

The tar separator is provided with a heat exchanger assembly, the air inlet is arranged on the connection of the lower head, the air outlet is arranged at the top of the tar separator, and the tar discharge port is arranged at the top of the tar separator. bottom;

a condenser, the gas-liquid mixture from the top of the gas outlet of the tar separator enters the condenser, and the thiophene is separated from the outlet of the condenser;

Pressure cooling processor, the gas-liquid mixture processed by the condenser enters two pressure cooling processors in turn, and the volume of the second pressure cooling processor is twice the volume of the first pressure cooling processor; The liquefied gas from the two pressure cooling processors is circulated to the butadiene intake pipe through the pipeline.

Hydrogen sulfide recovery station, the hydrogen sulfide gas from the top of the second pressurized cooling processor enters the hydrogen sulfide recovery station, the hydrogen sulfide recovery station includes: a plurality of hydrogen sulfide pipelines, the initial end of each hydrogen sulfide pipeline is They are respectively connected with the outlet of the scrubbing tower, and each hydrogen sulfide pipeline is respectively equipped with a waste acid recovery line, and all the waste acid recovery lines are respectively connected with the main line, which is connected with the input end of the waste acid recovery tank.

Optionally, the mixer includes:

The first mixing chamber, the sulfur gas pipeline extends from the top into the first mixing chamber and extends to the near bottom of the first mixing chamber, and a number of small holes are evenly arranged on the side wall of the sulfur gas pipeline, and the small holes The total area is less than or equal to the cross-sectional area of the sulfur gas pipeline; the butadiene gas pipeline is arranged on the side of the first mixing chamber;

a throat pipe, which is tightened inward at the bottom of the first mixing chamber to reduce its diameter and extend downward;

The second mixing chamber expands outward from the bottom of the throat to increase its diameter and extend downward.

Optionally, the sulfur gas pipeline and the butadiene gas pipeline are arranged at right angles, so that the flow direction of the sulfur gas and the flow direction of the butadiene gas are at right angles.

Optionally, the constricted angle between the first mixing chamber and the throat is 30 to 45 degrees; the expansion angle between the throat and the second mixing chamber is 8 to 20 degrees.

Optionally, the connecting pipelines between the mixers, the connecting pipelines between the mixers and the tar separator, and the connecting pipelines between the tar separator and the condenser are all erected or assembled at a 45-degree angle.

Optionally, the volume of the tar separator is 5M ³ to 10M ³ in volume, the aspect ratio is 2 to 1, and it is installed vertically.

Optionally, condensing heat exchange tubes are respectively added in the pressurization and cooling processor, which are installed vertically.

Optionally, the inlet position of the hydrogen sulfide gas entering the first pressurization and cooling processor is set above the welding line of the lower head, and the hydrogen sulfide outlet is set at the highest position of the second pressurization and cooling processor.

Optionally, the output end of the waste acid recovery tank is connected to the inlet of the scrubber tower.

The technical scheme of the present invention has the following advantages:

This embodiment provides a thiophene production and circulation system, which significantly reduces the generation of tar, improves the generation rate of thiophene, and recycles other hydrogen components and heavy components generated at the same time; the generated hydrogen sulfide gas is further recovered. processing, energy saving and environmental protection.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative efforts.

Fig. 1 is the structural representation of the mixer of the present invention;

Fig. 2 is the structural representation of the present invention;

3 is a schematic structural diagram of a hydrogen sulfide gas recovery station.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limiting the invention.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

The present invention also provides a thiophene production and circulation system, as shown in FIG. 2 , two mixers are arranged on the reaction pipeline before and after, which are the first production mixer 1 and the second production mixer 2 respectively. The sulfur gas pipeline is divided into two parts. Another branch extends from the top of the second production mixer 2 . The connecting pipes of the first production mixer 1 and the second production mixer 2 are at an angle of 45 degrees to the horizontal plane.

Specifically, the production of thiophene requires full mixing of butadiene and sulfur in the early stage of the reaction. This embodiment provides a self-designed mixer for mixing, as shown in FIG. 1 , including:

In the first mixing chamber 30 , the sulfur gas pipeline 10 extends from the top to the bottom of the first mixing chamber 30 before extending into the first mixing chamber 30 , and 2 to 6 small holes are evenly arranged on the side wall of the sulfur gas pipeline 10 50, and the total area of the small holes is less than or equal to the cross-sectional area of the sulfur gas pipeline 10; the butadiene gas pipeline 20 is arranged on the side of the first mixing chamber 30;

Throat pipe 40, the diameter of the throat pipe is 100mm, the diameter of the reaction pipe is 219mm, the length of the throat pipe is 100mm to 150mm, and the bottom of the first mixing chamber 30 is tightened inward to reduce the diameter and extend downward; the throat pipe is the process of gathering energy , this energy is also the hybrid force where the two gases form the largest shear force with each other, and the throat is also the place where the two gases are most mixed. Due to the short mixing time, it is necessary to increase the mixing expansion section, and use the energy accumulated at the throat to expand The segment continues shear mixing. The diameter of the throat pipe needs to be determined according to two gas flow rates, and is obtained through CFD simulation calculation. The diameter and length of the throat pipe in this embodiment are based on the specific process of the present application. If the throat section is too long, the resistance is too large and the production cost is high. The shrinkage angle of the shrinking section 70 is 30 to 45 degrees, and 30 degrees is used in this embodiment. The two gases must be sheared and mixed with each other in the pipeline. This shearing and mixing process requires energy supply, so only the shrinkage The pipeline gathers energy to make this process happen. When shrinking the pipeline, resistance will inevitably occur. In order to reduce the resistance of the gas flow rate, it must be contracted according to a certain angle. CFD simulation calculation is performed at an angle of 30 to 45 degrees, the resistance is the least, and the energy loss is the least.

The expansion angle of the expansion section 80 is 8 to 20 degrees, which is 20 degrees in this embodiment. The shear mixing of the two gases in the expansion section uses the energy accumulated at the throat and released in the expansion section. This angle is simulated by CFD. The energy loss of the angular pipe diameter expansion is the smallest, and the two gases can also maximize shear mixing in the process of releasing energy in the pipe expansion section. If there is no expansion section, that is, a 90-degree angle change in diameter, the pressure drop in the pipeline is maximized, the energy loss is the largest, and the two gases have not yet reached the maximum or maximum degree of mixing.

The second mixing chamber 60 expands outward from the bottom of the throat 40 to increase its diameter and extend downward.

The flow direction of the sulfur gas and the butadiene gas are at right angles; when mixing, the maximum shear force mixing of the two gases is achieved through the angle, so as to maximize the mixing.

The gas ratio of sulfur gas and butadiene gas is 1-5, that is, the gas flow of sulfur gas cannot be sprayed to the pipe wall, but it is close to the pipe wall, and the effect is the best.

While the sulfur gas and the butadiene gas need to be fully mixed, the sulfur needs to be added to the reaction system twice, so that the molar ratio of the sulfur and butadiene does not exceed 2. First, the sulfur and butadiene are mixed and reacted twice:

The first mixing ratio of sulfur atom and butadiene molar ratio is 1.0-1.7;

The second mixing ratio sulfur atom and butadiene molar ratio is 0.5-1.2;

The total raw material sulfur atom and butadiene molar ratio is 1.8-2.0.

In terms of ingredient ratio, reducing the ratio of sulfur molar ratio not more than 2 will reduce the generation of carbon disulfide and a small amount of dihydrothiophene. The unreacted raw butadiene and dihydrothiophene will be recycled, which will significantly increase the reaction yield. The amount of tar was significantly reduced. The light components of the distillation column and the heavy components below 130°C participate in the recycle reaction.

In the thiophene production process, the kinetic energy of the two fluids of sulfur gas and butadiene is not much different, so it is not suitable to use a typical Venturi mixer. steam flow, which can significantly increase production costs. The mixer of this embodiment solves the problem that the momentum difference between the two fluids is not large, and does not affect the flow resistance of the other fluid. In addition, the butadiene substance is an active substance, which is very easy to polymerize, so it is not suitable for living in a system with pressure, so it is not suitable for increasing the kinetic energy of the fluid by means of pressurization.

The technological process using the above-mentioned production mixer is as follows:

The liquid sulfur and water are heated to 450～550℃ to form steam-sulfur gas; the gasified butadiene is mixed with water and heated to 250～350℃ to form steam-butadiene gas. Mixing steam-sulfur gas and steam-butadiene gas, and reacting at 360-460° C. under slightly positive pressure conditions, the residence time of the materials in the reactor is 3-8 seconds, and a gas reaction product is obtained. The mass ratio of sulfur entering the reactor twice in this process is set to 1.5, that is, the molar ratio to butadiene is 2.0, and the molar mass of sulfur per unit of time is 1.2 to 0.8.

Preferably, the mixer and the pipeline reactor are assembled at an angle of upright or 45 degrees, the main reason is that tar is always produced during the reaction process, so the assembly is beneficial to the tar removal reaction system and can continue production for a long time.

A tar collection tank 3 needs to be set up in the production system. The tar tank 3 needs a certain volume and has the function of a heat exchanger. The temperature of the gas entering the tar tank 3 is as high as 350 degrees or more, and the temperature from the outlet of the tar tank 3 is controlled at Between 180 degrees and 200 degrees. The tar tank is made of stainless steel, the volume is 5M ³ to 10M ³ , the length-diameter ratio is 2 to 1, and it is installed vertically. Set at the lowest end of the tar tank after discharge. With enough separation space, the pressure difference drops significantly, the gas flow rate is significantly reduced, the liquefied or atomized high boiling point substances and tar can be easily separated from the gas by their own weight, and the gas and tar are separated to the maximum extent.

After the gas enters the tar tank, the reaction ends, and the follow-up is the physical treatment process. The unreacted raw butadiene in the tail gas is recycled, the reaction yield is significantly increased, and the amount of tar is significantly reduced. The light components of the distillation column and the heavy components below 130°C participate in the recycle reaction.

The gas-liquid mixture from the top of the gas outlet of the tar separator enters the condenser 4, and thiophene is separated from the outlet of the condenser 4;

The gas-liquid mixture after being processed by the condenser 4 enters two pressurized cooling processors successively, and the volume of the second pressurized and cooled processor 6 is twice the volume of the first pressurized and cooled processor 5; The liquefied gas from the pressure cooling processor 6 is circulated to the butadiene intake pipe through the pipeline. Specifically, the pressure cooling processor of the thiophene production device with an annual output of 3,000 tons, that is, the first hydrogen sulfide processor (collection irrigation) volume 9.5 M ³ , the volume of the second hydrogen sulfide processor is 23M ³ , the purpose is to reduce the gas flow rate and maximize the separation of gas-liquid substances; 5M ² condensation heat exchange tubes are added in the two hydrogen sulfide processors respectively, which are arranged in the processors (collecting The purpose is to fully condense the gas and maximize the separation of the liquid: the inlet position of the hydrogen sulfide gas entering the hydrogen sulfide collection tank is set above the welding line of the lower head, and the hydrogen sulfide outlet is set at the highest part of the collection tank; two The condensers all need to be installed vertically, the purpose is to have a large gas-liquid separation space and a long gas residence time. The condensing temperature of the first condenser is controlled within the range of 5-10°C, and the pressure is set at 10-12Mpa, mainly collecting thiophene and part of carbon disulfide. The temperature of the second condenser is controlled at -10--5℃, and the pressure is set at 20-23Mpa, mainly to collect low-boiling substances such as butadiene and a small amount of carbon disulfide, also known as tail gas liquefied gas.

Further, the hydrogen sulfide outlet enters the hydrogen sulfide recovery and treatment station, as shown in Figure 3, which includes: mainly composed of hydrogen sulfide pipeline, neutralization waste liquid recovery pipeline, main pipeline and waste liquid recovery tank, etc.; five hydrogen sulfide pipelines are parallel And the interval is set, the initial end of each hydrogen sulfide pipeline is connected with the corresponding gas scrubber outlet respectively; Namely, the No. 1 gas scrubber 101 is connected with the No. 1 hydrogen sulfide pipeline 105, and the No. 2 gas scrubber 102 is connected with the No. 2 hydrogen sulfide pipeline. 106 is connected, the third scrubber 103 is connected with the third hydrogen sulfide pipeline 107, the fourth scrubber 104 is connected with the fourth hydrogen sulfide pipeline 104, and the fifth scrubber 205 is connected with the fifth hydrogen sulfide pipeline 108. The scrubber is neutralized with ammonia and hydrogen sulfide.

The low points of each hydrogen sulfide pipeline are respectively provided with corresponding waste liquid recovery pipelines 110. Five waste liquid recovery pipelines 110 are collected into one main line, and the main line is connected to the input end at the top of the waste liquid recovery tank 111. The bottom of the recovery tank 111 is provided with an output end, and the output end is connected to the bottom inlet of the No. 4 scrubbing tower 112, and the neutralized waste liquid in the hydrogen sulfide pipeline flows into the No. 4 scrubbing tower 112 by self-flow, which avoids waste acid discharge. The environment causes pollution, and the recycling of ammonia sulfide is realized.

Other unexplained equipment in the equipment flow chart are mainly functional equipment for separating gas and liquid substances, cooling and collecting products thiophene and hydrogen sulfide.

Experimental example 1

No tail gas liquefied gas circulation, no mixer, when the molar ratio of butadiene and sulfur atoms is 1:2.5, the production speed of tar is faster, the tar storage tank is blocked on the seventh day, and the processing is stopped.

Experimental example 2

When the tail gas liquefied gas circulation is not used, the mixer is used, and the molar ratio of butadiene and sulfur atoms is 1:2.5, the tar storage tank is blocked on the 20th day, and the processing is stopped. The yield of thiophene was not improved significantly.

Experimental example 3

When the tail gas liquefied gas circulation is adopted, the mixer is used, and the molar ratio of butadiene and sulfur atoms is 1:2.5, the tar storage tank is blocked on the 25th day, and the treatment is stopped. Thiophene yield increased by 4%.

Experimental example 4

When the tail gas liquefied gas circulation is adopted, a mixer is used, and the molar ratio of butadiene and sulfur atoms is 1:2.1, the tar storage tank is blocked on the 50th day, and the treatment is stopped. Product yield increased by 10%.

Experimental example 5

When the tail gas liquefied gas circulation is adopted, the mixer is used, and the molar ratio of butadiene and sulfur atoms is 1:2, the tar storage tank is blocked on the 68th day, and the treatment is stopped. Product yield increased by 12%.

Experimental example 6

When the tail gas liquefied gas circulation is adopted, the mixer is used, and the molar ratio of butadiene and sulfur atoms is 1:1.8, the tar storage tank is blocked on the 85th day, and the treatment is stopped. Product yield increased by 15%.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (9)

1. The thiophene production recycling system is characterized by comprising:

the two mixers are arranged on the reaction pipeline in the front and back direction and are respectively a first production mixer and a second production mixer, the butadiene gas inlet pipeline is communicated with the side part of the first production mixer, the sulfur gas inlet pipeline is divided into two branches and is respectively communicated with the top parts of the first production mixer and the second production mixer, and the gas-liquid outlet is arranged below the second production mixer;

the tar separator is internally provided with a heat exchanger assembly, an air inlet of the heat exchanger assembly is arranged above the joint of the lower end socket, an air outlet of the heat exchanger assembly is arranged at the top end of the tar separator, and a tar discharge port is arranged at the bottommost end of the tar separator;

the gas-liquid mixture from the top end of the gas outlet of the tar separator enters the condenser, and the thiophene is separated from the outlet of the condenser;

the gas-liquid mixture treated by the condenser sequentially enters the two pressurizing and cooling processors, and the volume of the second pressurizing and cooling processor is twice of that of the first pressurizing and cooling processor; the liquefied gas from the second pressurizing and cooling processor is circulated to a butadiene gas inlet pipeline through a pipeline;

and the hydrogen sulfide gas from the top of the second pressurizing and cooling processor enters the hydrogen sulfide recycling station, and the hydrogen sulfide recycling station comprises: the hydrogen sulfide pipeline comprises a plurality of hydrogen sulfide pipelines, wherein the initial end of each hydrogen sulfide pipeline is respectively connected with the outlet of the gas washing tower, a waste acid recovery pipeline is respectively installed on each hydrogen sulfide pipeline, all the waste acid recovery pipelines are respectively connected with a main pipeline, and the main pipeline is connected with the input end of a waste acid recovery tank.

2. The thiophene production cycle recycle system of claim 1, wherein the mixer comprises:

the sulfur gas pipeline extends into the first mixing cavity from the top and extends to the position close to the bottom of the first mixing cavity, a plurality of small holes are uniformly formed in the side wall of the sulfur gas pipeline, and the total area of the small holes is smaller than or equal to the cross section area of the sulfur gas pipeline; the butadiene gas pipeline is arranged on the side part of the first mixing cavity;

the throat pipe is tightened inwards at the bottom of the first mixing cavity to enable the diameter of the throat pipe to be reduced and extend downwards;

and the second mixing cavity expands outwards from the bottom of the throat pipe to increase the diameter of the throat pipe and extends downwards.

3. The thiophene production cycle recycle system of claim 2, wherein the sulfur gas conduit is disposed at a right angle to the butadiene gas conduit such that the sulfur gas flow direction is at a right angle to the butadiene gas flow direction.

4. The thiophene production recycling system of claim 3, wherein a contraction included angle between the first mixing cavity and the throat is 30 to 45 degrees; the expansion angle of the throat pipe and the second mixing cavity is 8-20 degrees.

5. The thiophene production cycle recycle system of claim 1, wherein the connecting piping between the mixers, the connecting piping between the mixer and the tar separator, and the connecting piping between the tar separator and the condenser are all assembled upright or at a 45 degree angle.

6. The thiophene production recycling system of claim 1, wherein the tar separator has a volume of 5M³～10M³The length-diameter ratio is 2: 1, and the device is vertically installed.

7. The thiophene production recycling system of claim 1, wherein the pressurization and temperature reduction processor is internally and additionally provided with condensation heat exchange tubes which are vertically installed.

8. The thiophene production recycling system of claim 1, wherein an inlet of hydrogen sulfide gas into the first pressure and temperature reduction processor is arranged above a welding line of the lower head, and a hydrogen sulfide outlet is arranged at the highest position of the second pressure and temperature reduction processor.

9. The thiophene production cycle recycle system of claim 1, wherein an output end of the spent acid recovery tank is connected to an inlet of the scrubber tower.

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