Production equipment and process for synthesizing thiophene through reaction of butadiene and sulfur

Abstract

The invention relates to the field of thiophene chemical synthesis, and discloses production equipment and process for synthesizing thiophene through reaction of butadiene and sulfur, and the equipment comprises a butadiene treatment mechanism used for performing dehydration and deoxidation treatment on butadiene through molecular sieve adsorption and catalytic deoxidation; the sulfur treatment mechanism is used for preparing sulfur nano slurry through air jet pulverization and dispersion; and the reaction mechanism is used for catalytic reaction and product treatment of butadiene and sulfur. The sulfur atom activity is synergistically improved through sulfur nanocrystallization and core-shell catalysis, and the bottlenecks of low conversion rate and by-product accumulation of a traditional process are broken through; a microwave dynamic regulation and control and micro-channel mass transfer strengthening technology is introduced, so that low-temperature and low-energy-consumption reaction is realized, and the coking risk is avoided; molecular sieve membrane anhydrous separation is adopted to replace a washing process, so that the product purity and environmental protection property are synchronously improved; by combining Claus sulfur closed-loop circulation and a nano regeneration system, the sulfur recovery rate is promoted to a new high level in the industry, and tail gas pollution is eradicated.

Description

Technical Field

[0001] The invention relates to the field of thiophene chemical synthesis, and in particular to production equipment and a process for synthesizing thiophene by reacting butadiene with sulfur. Background Art

[0002] The industrial production of thiophene compounds has long relied on the high-temperature catalytic reaction of sulfur and olefins, but the traditional process has significant shortcomings in sulfur atom utilization efficiency, energy consumption control and environmental compatibility. First, sulfur raw materials are usually added directly in micron-sized particles, and the insufficient specific surface area leads to limited reaction activity. The incompletely reacted sulfur accumulates in the form of residues, the unit consumption remains high, and the extensive dispersion system easily causes sulfur atom agglomeration, further aggravating the side reaction to form impurities such as dithiophene. The existing technology attempts to improve the activity of sulfur through mechanical crushing or water dispersion, but the particle size control accuracy is insufficient, and there is a lack of catalyst design for the sulfur atom activation pathway, which cannot achieve a simultaneous breakthrough in reaction efficiency and selectivity.

[0003] Secondly, the reaction process relies on high-temperature heating and tubular reactors, and energy consumption and equipment coking are prominent problems. Conventional electric heating needs to be maintained above 300°C to drive the reaction, resulting in uncontrolled butadiene thermal polymerization side reactions. At the same time, the inner wall of the reactor needs to be frequently shut down for cleaning due to high-temperature carbon deposition. Existing separation processes mostly use water washing methods, which can partially remove impurities, but produce high-COD sulfur-containing wastewater, and the cost of environmental protection treatment has increased sharply. Some studies have attempted to introduce membrane separation technology, but have not solved the problem of balancing the transmembrane pressure difference and membrane life, making it difficult to meet continuous production needs.

[0004] Finally, there is a serious technical gap in sulfur resource recovery and tail gas treatment. The traditional process directly incinerates unreacted sulfur and by-product H2S, resulting in zero sulfur recovery rate and excessive SO2 emissions. The sulfur recovery rate of the low-temperature Claus reaction is less than 70% due to catalyst deactivation and by-product generation. The existing technology lacks a full-chain collaborative design from sulfur activation, reaction regulation to product separation, resulting in the coexistence of resource waste and environmental pollution, making it difficult to meet the industrial upgrading needs of green chemical industry.

[0005] Therefore, the present invention proposes a production device and a process for synthesizing thiophene by reacting butadiene with sulfur to solve the deficiencies of the prior art. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a production device and a process for synthesizing thiophene by reacting butadiene with sulfur, which solves the industrial bottleneck problems of low sulfur atom utilization, uncontrolled by-products, excessive wastewater discharge and sulfur cycle failure.

[0007] To achieve the above object, the present invention is implemented by the following technical scheme: a production device for synthesizing thiophene by reacting butadiene with sulfur, characterized in that it comprises: A butadiene treatment mechanism for dehydrating and deoxygenating butadiene by molecular sieve adsorption and catalytic deoxygenation; The butadiene processing mechanism comprises a butadiene storage tank, the raw material input and output ports of the butadiene storage tank are respectively connected to the input and output ports of the butadiene unloading crane pipe through pipelines, the purification output end of the butadiene storage tank is connected to the adsorption input end of the molecular sieve adsorption tower through a pipeline, the adsorption output end of the molecular sieve adsorption tower is connected to the deoxidation input end of the active copper deoxidation bed through a pipeline, and the deoxidation output end of the active copper deoxidation bed is connected to the reaction mechanism through pipeline a; Butadiene passes through the molecular sieve adsorption tower and the active copper deoxidation bed in turn to remove moisture and oxygen respectively. The molecular sieve adsorption tower uses 3A molecular sieve, and the active copper deoxidation bed uses Cu / Al2O3 as catalyst.

[0008] Molecular sieve adsorption: The pore size (0.3nm) of 3A molecular sieve selectively adsorbs water molecules (kinetic diameter 0.28nm), while butadiene molecules (kinetic diameter 0.45nm) cannot enter the pores, achieving efficient dehydration.

[0009] Catalytic deoxygenation: Cu / Al2O3 catalyst selectively oxidizes O2 with trace olefin impurities (such as 1,3-butadiene) in butadiene at 50-80°C to generate CO2 and H2O, thus avoiding the poisonous effect of oxygen on subsequent microwave catalytic reactions.

[0010] A sulfur processing mechanism for preparing sulfur nano-slurry by air flow pulverization and dispersion; The sulfur treatment mechanism includes a sulfur storage tank, the raw material output end of the sulfur storage tank is connected to the pulverization input end of the air flow pulverizer through a pipeline, the pulverization output end of the air flow pulverizer is connected to the slurry input end of the sulfur nano slurry storage tank 1 through a pipeline, and the pre-treated slurry output end of the sulfur nano slurry storage tank 1 is connected to the reaction mechanism through a pipeline b; Sulfur is crushed to nanoscale (D50=80-100nm) by a jet mill, dispersed in the ionic liquid [BMIM]PF6 to form a stable slurry (sulfur concentration 28-32%), and graphene quantum dots (GQDs) are added as a dispersion stabilizer.

[0011] Nano-sizing improves reaction activity: Nano-sulfur particles have a larger specific surface area and higher surface energy, making it easier to react with butadiene at the interface in a microwave field. The reaction rate is 3-5 times higher than that of traditional sulfur steam processes.

[0012] Ionic liquid dispersion system: The sulfur-phobic properties of [BMIM]PF6 and the π-π interaction of GQDs synergistically stabilize sulfur particles, prevent agglomeration, and ensure the uniformity of the slurry during pipeline transportation and reaction.

[0013] A reaction mechanism for the catalytic reaction of butadiene and sulfur and the treatment of the products.

[0014] Preferably, the reaction mechanism comprises a high-pressure atomizing nozzle, the first feed end and the second feed end of the high-pressure atomizing nozzle are respectively connected to a pipeline a and a pipeline b, the atomizing output end of the high-pressure atomizing nozzle is connected to the reactant input end of the microwave-microchannel reactor through a pipeline, the reactant output end of the microwave-microchannel reactor is connected to the separation input end of the gas-liquid separator through a pipeline, the liquid phase output end of the gas-liquid separator is connected to the membrane feed end of the molecular sieve membrane separator through a pipeline, and the membrane product output end of the molecular sieve membrane separator is connected to the rectification tower through a pipeline. The distillation input end of the distillation tower is connected to the finished product input end of the thiophene finished product storage tank through a pipeline, the gas phase output end of the gas-liquid separator is connected to the reaction gas input end of the Claus reactor through a pipeline, the sulfur gas output end of the Claus reactor is connected to the condensation input end of the sulfur condenser through a pipeline, the liquid sulfur output end of the sulfur condenser is connected to the nano-input end of the sulfur nano-system through a pipeline, and the nano-slurry output end of the sulfur nano-slurry storage tank 2 is connected to the circulation input end of the sulfur nano-slurry storage tank 2 through a pipeline.

[0015] The purified butadiene and sulfur nano-slurry are mixed through a high-pressure atomization nozzle and then enter a microwave-microchannel reactor, where they react to produce thiophene under the action of a core-shell catalyst (MoS2@HZSM-5).

[0016] Microwave field effect: The microwave frequency (2.40-2.50GHz) matches the dielectric loss characteristics of the MoS2 shell (5-8nm) in the core-shell catalyst, triggering local hot spots (local temperature > 300°C) and promoting the formation of sulfur-carbon bonds, while the overall system temperature only needs to be 180-250°C, reducing energy consumption by more than 40%.

[0017] Microchannel mass transfer enhancement: The microchannel structure with a single channel diameter of 180-220μm achieves ultra-uniform mixing of reactants through laminar shear force, shortens the residence time to 25-35 seconds, and avoids side reactions (such as thiophene polymerization).

[0018] Core-shell catalyst design: The HZSM-5 molecular sieve core (silicon-aluminum ratio of 20-30) provides acidic sites to promote the protonation of butadiene, and the MoS2 shell activates sulfur atoms through S vacancies, forming an "acid site-sulfur site" synergistic catalytic pathway with a selectivity of >95%.

[0019] The reaction products are fractionated by a gas-liquid separator, the liquid phase is purified by an MFI molecular sieve membrane (pore size 0.54-0.56 nm), and the gas phase H2S enters the Claus reactor to be converted into sulfur and nano-circulated.

[0020] Precise screening by molecular sieve membrane: The pore size of MFI molecular sieve membrane (0.54-0.56nm) is slightly larger than the molecular kinetic diameter of thiophene (0.48nm), allowing thiophene to pass through preferentially while large molecular byproducts (such as dithiophene) are retained, with a separation efficiency of >98%.

[0021] Sulfur in situ regeneration: TiO2 / Al2O3 catalyst oxidizes H2S to S in a Claus reactor (240-260°C) 0 Steam is condensed and nano-crystallized to form a circulating slurry, with a sulfur recovery rate of ≥95%, solving the problem of high sulfur consumption in traditional processes.

[0022] The present invention also provides a production process for synthesizing thiophene by reacting butadiene with sulfur, comprising the following steps: S1, subjecting the butadiene raw material to molecular sieve adsorption dehydration and copper-based catalytic deoxidation treatment in sequence to obtain purified butadiene, and transporting the purified butadiene to a reaction mechanism; S2, dispersing the sulfur raw material in the ionic liquid after air flow pulverization to form sulfur nano-slurry, and transporting the sulfur nano-slurry to the reaction mechanism; S3, mixing the purified butadiene with the sulfur nano-slurry and inputting the mixture into a microwave microchannel reactor for catalytic reaction to generate a thiophene-containing product; S4, separating the reaction product by gas-liquid separation, separating and purifying the liquid product by molecular sieve membrane to obtain crude thiophene, and converting the gas product by hydrogen sulfide reaction to recover sulfur; S5, the recovered sulfur is returned to the sulfur nano-slurry preparation step for recycling after being subjected to nano-treatment Preferably, the microwave frequency of the microwave-microchannel reactor is 2.40 GHz to 2.50 GHz, the dynamic adjustment range of microwave power is 1 kW to 5 kW, and the inner wall of the microwave-microchannel reactor is loaded with a core-shell structure catalyst, and the core-shell structure catalyst includes a molecular sieve core and a molybdenum sulfide shell layer.

[0023] Preferably, the inner core of the molecular sieve is a HZSM-5 molecular sieve, the silicon-aluminum molar ratio is 20:1 to 30:1, and the molybdenum sulfide shell layer has a thickness of 5nm to 8nm and is grown on the surface of the molecular sieve by an atomic layer deposition process.

[0024] Preferably, the particle size distribution of the sulfur particles in the sulfur nano-slurry satisfies D50 of 80nm to 100nm, D90 of no more than 150nm, the sulfur mass concentration is 28% to 32%, the dispersion medium is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, and graphene quantum dots are added as a dispersion stabilizer, and the addition amount of graphene quantum dots is 0.05% to 0.15% of the sulfur mass.

[0025] Preferably, the molecular sieve membrane used in the molecular sieve membrane separation and purification is an MFI type molecular sieve membrane with a pore size of 0.54 nm to 0.56 nm, an operating temperature of 70° C. to 90° C., and a transmembrane pressure difference of 0.3 bar to 0.5 bar.

[0026] Preferably, the hydrogen sulfide conversion reaction is carried out in a Claus reactor, the reaction temperature is 240° C. to 260° C., the catalyst is titanium dioxide-supported alumina, and the mass loading of titanium dioxide is 10% to 15%.

[0027] Preferably, the sulfur nano-processing adopts a gas flow pulverization process, the pulverization pressure is 0.6MPa to 0.8MPa, the particle size D50 of the sulfur particles after pulverization is 80nm to 100nm, and ionic liquid is dispersed to form a circulating slurry.

[0028] Preferably, the conditions of the catalytic reaction are reaction temperature of 180° C. to 250° C., system pressure of 0.08 MPa to 0.12 MPa, and material residence time of 25 seconds to 35 seconds.

[0029] The present invention provides a production device and process for synthesizing thiophene by reacting butadiene with sulfur. It has the following beneficial effects: 1. The present invention combines the sulfur nano-crystallization technology with the core-shell catalytic system design, which significantly improves the reaction activity of sulfur atoms and solves the problems of low conversion efficiency and by-product accumulation caused by coarse sulfur particles in traditional processes. Experimental data show that under non-nano-crystallized sulfur or ordinary catalyst systems, the reaction yield is less than 60% and the sulfur unit consumption surges. The present invention achieves efficient utilization of sulfur resources and precise inhibition of side reactions through the synergy of nano-dispersion and dual active sites.

[0030] 2. The present invention introduces microwave dynamic control and microchannel mass transfer enhancement technology. The present invention achieves a significant reduction in energy consumption under low temperature conditions, while completely avoiding the risk of high-temperature coking. The existing technology relies on electric heating or over-temperature reaction, and the equipment has a fast coking rate and high energy consumption. Experimental comparison shows that the traditional solution will have significant coking after one week of operation, and the energy consumption is nearly doubled. The present invention has outstanding continuous operation stability, and both energy consumption and maintenance costs are reduced.

[0031] 3. The present invention adopts molecular sieve membrane precision screening technology. The present invention directly produces high-purity products and completely avoids the wastewater pollution problem of traditional water washing process. The existing water washing separation has huge environmental pressure due to the co-dissolution of impurities and the discharge of high-concentration wastewater. Experiments have shown that the purity of the product of the water washing process is less than 90% and the cost of wastewater treatment has increased sharply. The molecular sieve membrane achieves a purity jump and zero wastewater discharge simultaneously through the water-free separation path.

[0032] 4. The present invention is based on the closed-loop design of the Claus reaction and nano-sulfur regeneration system. The present invention pushes the sulfur recovery rate to a new high in the industry and completely eliminates sulfur resource waste and tail gas pollution. In traditional incineration or low-temperature recovery schemes, sulfur consumption surges and by-products are out of control. Experiments show that the sulfur recovery rate of the unclosed-loop system approaches zero, and the tail gas sulfide seriously exceeds the standard. The present invention achieves the dual advantages of sulfur resource circulation and emission through temperature-catalyst-regeneration synergy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of the production equipment of the present invention; Figure 2 is a flow chart of the butadiene processing mechanism of the present invention; Figure 3 is a flow chart of the sulfur treatment mechanism of the present invention; Figure 4 It is a reaction mechanism flow chart of the present invention; Figure 5 It is a flow chart of the preparation process of the present invention.

[0034] Among them, 1. Butadiene processing mechanism; 101. Butadiene unloading crane pipe; 102. Butadiene storage tank; 103. Molecular sieve adsorption tower; 104. Active copper deoxidation bed; 2. Sulfur processing mechanism; 201. Sulfur storage tank; 202. Air flow pulverizer; 203. Sulfur nano-slurry storage tank one; 3. Reaction mechanism; 301. High-pressure atomizing nozzle; 302. Microwave-microchannel reactor; 303. Gas-liquid separator; 304. Claus reactor; 305. Sulfur condenser; 306. Sulfur nano-system; 307. Sulfur nano-slurry storage tank two; 308. Molecular sieve membrane separator; 309. Distillation tower; 3010. Thiophene finished product storage tank. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1 The embodiment of the present invention provides a production device for synthesizing thiophene by reacting butadiene with sulfur, comprising: A butadiene treatment mechanism 1, for dehydrating and deoxygenating butadiene by molecular sieve adsorption and catalytic deoxygenation; The butadiene processing mechanism 1 comprises a butadiene storage tank 102, the raw material input and output ports of the butadiene storage tank 102 are respectively connected to the input and output ports of the butadiene unloading crane 101 through pipelines, the purification output end of the butadiene storage tank 102 is connected to the adsorption input end of the molecular sieve adsorption tower 103 through a pipeline, the adsorption output end of the molecular sieve adsorption tower 103 is connected to the deoxidation input end of the active copper deoxidation bed 104 through a pipeline, and the deoxidation output end of the active copper deoxidation bed 104 is connected to the reaction mechanism 3 through a pipeline a; The sulfur processing mechanism 2 is used for preparing sulfur nano-slurry by air flow crushing and dispersion; The sulfur treatment mechanism 2 includes a sulfur storage tank 201, a raw material output end of the sulfur storage tank 201 is connected to a pulverization input end of an air flow pulverizer 202 through a pipeline, a pulverization output end of the air flow pulverizer 202 is connected to a slurry input end of a sulfur nano-slurry storage tank 203 through a pipeline, and a pre-treated slurry output end of the sulfur nano-slurry storage tank 203 is connected to a reaction mechanism 3 through a pipeline b; Reaction mechanism 3, used for catalytic reaction of butadiene and sulfur and product treatment; The reaction mechanism 3 includes a high-pressure atomizing nozzle 301, a first feed end and a second feed end of the high-pressure atomizing nozzle 301 are respectively connected to a pipeline a and a pipeline b, an atomizing output end of the high-pressure atomizing nozzle 301 is connected to a reactant input end of a microwave-microchannel reactor 302 through a pipeline, a reactant output end of the microwave-microchannel reactor 302 is connected to a separation input end of a gas-liquid separator 303 through a pipeline, a liquid phase output end of the gas-liquid separator 303 is connected to a membrane feed end of a molecular sieve membrane separator 308 through a pipeline, and a membrane product output end of the molecular sieve membrane separator 308 is connected to a distillation output end of a distillation tower 309 through a pipeline. The input end of the distillation tower 309 is connected to the finished product input end of the thiophene finished product storage tank 3010 through a pipeline, the gas phase output end of the gas-liquid separator 303 is connected to the reaction gas input end of the Claus reactor 304 through a pipeline, the sulfur gas output end of the Claus reactor 304 is connected to the condensation input end of the sulfur condenser 305 through a pipeline, the liquid sulfur output end of the sulfur condenser 305 is connected to the nano-input end of the sulfur nano-system 306 through a pipeline, and the nano-slurry output end of the sulfur nano-slurry storage tank 2 307 is connected through a pipeline.

[0037] Specifically, the butadiene unloading crane 101 is used to receive external butadiene raw materials and input them into the storage tank; the butadiene storage tank 102 is used to temporarily store the butadiene raw materials; the molecular sieve adsorption tower 103 is used to adsorb the moisture in butadiene (H2O≤10ppm) through the 3A molecular sieve; the active copper deoxidation bed 104 is used to remove oxygen (O2≤50ppm) using the Cu / Al2O3 catalyst; the butadiene raw materials enter the storage tank through the unloading crane, and then are dehydrated through the molecular sieve adsorption tower 103 and deoxidized through the active copper deoxidation bed 104 in sequence, and finally transported to the reaction mechanism 3 through the pipeline a; Sulfur storage tank 201: storing solid sulfur raw materials; air flow mill 202: crushing sulfur to nanometer level (D50=80nm) with 0.8MPa air flow; sulfur nano-slurry storage tank 1 203: storing nano-dispersed slurry (concentration 32%) of sulfur and ionic liquid ([BMIM]PF6); sulfur enters air flow mill 202 from the storage tank to be nano-sized, dispersed in ionic liquid to form stable slurry, and transported to reaction mechanism 3 through pipeline b; High-pressure atomizing nozzle 301: atomizes butadiene and sulfur slurry to form micron-sized droplets; microwave-microchannel reactor 302: microwave dynamic control (1-5kW) combined with microchannels (diameter 180μm) to enhance mass transfer and generate thiophene at low temperature; gas-liquid separator 303: separates the gas-liquid two-phase products after the reaction, the liquid phase enters the molecular sieve membrane separator 308, and the gas phase enters the Claus system; molecular sieve membrane separator 308: MFI type molecular sieve membrane (pore size 0.55nm) intercepts impurities such as dithiophene to improve the purity of thiophene degree to 99.4%; distillation tower 309: distill and purify the product after membrane separation, and store it in thiophene finished product storage tank 3010; Claus reactor 304: catalytic conversion of H2S in the gas phase into elemental sulfur (temperature 260°C, TiO2 / Al2O3 catalyst); sulfur condenser 305: condense and recover liquid sulfur generated by Claus reaction; sulfur nano-crystallization system 306: re-nano-crystallize the recovered sulfur and disperse it into slurry; sulfur nano-slurry storage tank 2 307: store the regenerated sulfur slurry, and circulate it to the reaction system through pipelines; After the reaction, the gaseous H2S is converted into sulfur through the Claus system, condensed and nanosized and then put back into the reaction; the liquid product is separated and purified by a molecular sieve membrane, and the finished thiophene is obtained after distillation; the entire process achieves near-zero loss of sulfur resources, zero wastewater discharge and efficient product output.

[0038] See also Figure 2 : Example 1: Highly active sulfur nano-slurry and short-time microwave reaction Raw material ratio (mass fraction) Butadiene raw material: 100 parts; sulfur raw material: 75 parts; ionic liquid [BMIM] PF6: 25 parts; graphene quantum dots (GQDs): 0.05 parts (based on sulfur mass); Process parameters Sulfur nanoparticles: Air flow crushing pressure: 0.8MPa; sulfur particle size: D50=80nm, D90=140nm; slurry concentration: 32%; Butadiene pretreatment: Molecular sieve adsorption tower: 3A molecular sieve, H2O content after dehydration = 8ppm; Active copper deoxidation bed: Cu / Al2O3 catalyst, O2 content after deoxidation = 40ppm; Microwave catalytic reaction: Microwave frequency: 2.50GHz, power dynamic adjustment range: 5kW; Reaction temperature: 250°C, pressure: 0.12MPa, residence time: 25 seconds; Core-shell catalyst: HZSM-5 Si-Al ratio = 30:1, MoS2 shell thickness = 5nm; Separation and circulation: Molecular sieve membrane: MFI type, transmembrane pressure difference = 0.5 bar, operating temperature = 90 ° C; Claus reactor: temperature = 260 °C, TiO2 / Al2O3 catalyst (TiO2 loading = 15%); Sulfur recovery rate = 98%, thiophene purity = 99.9%.

[0039] Example 2: Low temperature energy-saving process Raw material ratio (mass fraction) Butadiene raw material: 100 parts; sulfur raw material: 70 parts; ionic liquid [BMIM] PF6: 30 parts; graphene quantum dots (GQDs): 0.10 parts (based on sulfur mass); Process parameters Sulfur nanoparticles: Air flow crushing pressure: 0.6MPa; sulfur particle size: D50=100nm, D90=150nm; slurry concentration: 28%; Butadiene pretreatment: Molecular sieve adsorption tower: 3A molecular sieve, H2O content after dehydration = 10ppm; Active copper deoxidation bed: Cu / Al2O3 catalyst, O2 content after deoxidation = 50ppm; Microwave catalytic reaction: Microwave frequency: 2.40GHz, power dynamic adjustment range: 1kW; Reaction temperature: 180°C, pressure: 0.08MPa, residence time: 35 seconds; Core-shell catalyst: HZSM-5 Si-Al ratio = 20:1, MoS2 shell thickness = 8nm; Separation and circulation: Molecular sieve membrane: MFI type, transmembrane pressure difference = 0.3 bar, operating temperature = 70 ° C; Claus reactor: temperature = 240 °C, TiO2 / Al2O3 catalyst (TiO2 loading = 10%); Sulfur recovery rate = 95%, thiophene purity = 99.5%.

[0040] Example 3: Customized production of high-purity thiophene Raw material ratio (mass fraction) Butadiene raw material: 100 parts; sulfur raw material: 80 parts; ionic liquid [BMIM] PF6: 20 parts; graphene quantum dots (GQDs): 0.15 parts (based on sulfur mass); Process parameters Sulfur nanoparticles: Air flow crushing pressure: 0.7MPa; sulfur particle size: D50=90nm, D90=145nm; slurry concentration: 30%; Butadiene pretreatment: Molecular sieve adsorption tower: 3A molecular sieve, H2O content after dehydration = 5ppm; Active copper deoxidation bed: Cu / Al2O3 catalyst, O2 content after deoxidation = 30ppm; Microwave catalytic reaction: Microwave frequency: 2.45GHz, power dynamic adjustment range: 3kW; Reaction temperature: 220°C, pressure: 0.10MPa, residence time: 30 seconds; Core-shell catalyst: HZSM-5 Si-Al ratio = 25:1, MoS2 shell thickness = 6nm; Separation and circulation: Molecular sieve membrane: MFI type, transmembrane pressure difference = 0.4 bar, operating temperature = 80 ° C; Claus reactor: temperature = 250 °C, TiO2 / Al2O3 catalyst (TiO2 loading = 12%); Sulfur recovery rate = 97%, thiophene purity = 99.95% (pharmaceutical grade).

[0041] Comparative Example 1 (Sulfur Nano-Chemistry Failure) Compared with Example 1, the difference is that the sulfur is not subjected to nano-processing, and ordinary sulfur powder (D50=10 μm) is directly used, and the rest is the same.

[0042] Comparative Example 2 (Microwave Field Removal) Compared with Example 1, the difference is that the microwave energy input is cancelled and traditional electric heating (temperature = 250° C.) is adopted, and the rest are the same.

[0043] Comparative Example 3 (core-shell catalyst replacement) Compared with Example 1, the difference is that the core-shell catalyst is replaced by ordinary MoS2 powder (without HZSM-5 core), and the rest is the same.

[0044] Comparative Example 4 (Sulfur cycle closed) Compared with Example 1, the difference is that the Claus reactor and the sulfur nano-crystallization system are closed, and H2S is directly incinerated, and the rest are the same.

[0045] Comparative Example 5 (Molecular Sieve Membrane Removal) Compared with Example 2, the difference is that the molecular sieve membrane separation is cancelled and the traditional water washing separation is used instead, and the rest is the same.

[0046] Comparative Example 6 (Breakthrough in Low-Temperature Reaction Conditions) Compared with Example 2, the difference is that the reaction temperature is increased to 300° C. (outside the range of 180-250° C. of the present invention), and the rest is the same.

[0047] Comparative Example 7 (Ionic Liquid Replacement) Compared with Example 3, the difference is that the ionic liquid [BMIM]PF6 is replaced by water (sulfur slurry concentration = 10%), and the rest is the same.

[0048] Comparative Example 8 (Transmembrane pressure difference exceeds the standard) Compared with Example 3, the difference is that the transmembrane pressure difference of the molecular sieve membrane is increased to 1.0 bar (outside the range of 0.3-0.5 bar), and the rest are the same.

[0049] Comparative Example 9 (Claus reaction temperature exceeded the standard) Compared with Example 3, the difference is that the temperature of the Claus reactor is adjusted to 200° C. (lower than the range of 240-260° C. of the present invention), and the rest are the same.

[0050] Experiment 1: Sulfur nanoparticles and catalytic system verification Experimental Description Experimental purpose: To verify the synergistic effect of sulfur nano-sizing, core-shell catalyst and ionic liquid dispersion medium on reaction activity and selectivity.

[0051] Experimental steps: Sulfur treatment: Example 1: Sulfur was treated with a jet mill (0.8 MPa) to a particle size of 80 nm, dispersed in [BMIM]PF6 ionic liquid (sulfur concentration 32%), and 0.05% GQDs were added.

[0052] Comparative Example 1: Sulfur was not crushed (D50=10 μm) and was directly mixed with butadiene.

[0053] Comparative Example 3: Sulfur nanoparticles (D50=80nm), but the catalyst is replaced by ordinary MoS2 powder.

[0054] Comparative Example 7: Sulfur nanoparticles (D50=80 nm), but the dispersion medium is replaced by water (sulfur concentration 10%).

[0055] Butadiene pretreatment: All groups of butadiene were dehydrated (H2O≤10ppm) and deoxygenated (O2≤50ppm) by 3A molecular sieve.

[0056] Catalytic reaction: Example 1, Comparative Example 1 / 3 / 7: reaction temperature 250°C, pressure 0.12 MPa, residence time 25 seconds.

[0057] Microwave power: Example 1 = 5 kW, Comparative Examples 1 / 3 / 7 turned off the microwave and used electric heating.

[0058] Product analysis: Gas chromatography (GC) analysis of thiophene yield and by-product content; Laser particle size analyzer detects the distribution of sulfur residual particles; XPS was used to characterize the sulfur species on the catalyst surface.

[0059] Data Records: Each set of experiments was repeated three times, and the average value was taken to record the yield, sulfur consumption, selectivity and sulfur residue.

[0060] The experimental data are shown in Table 1 Table 1: Data table of the effects of sulfur form and catalyst type on reaction performance * Note: In Comparative Example 7, sulfur agglomerates due to water dispersion, and the actual particle size increases to 500 nm.

[0061] Experimental Summary This experiment verified the core mechanism of the present invention in reducing the activation energy of the reaction and improving the selectivity through the three-dimensional synergy of sulfur nano-size, core-shell catalyst and dispersion medium. First, the specific surface area of ​​nano-sulfur particles (D50=80nm) is about 20 times that of micron-sized sulfur (D50=10μm), and the exposure of surface sulfur atoms is significantly improved, which makes it easier to react with butadiene in the microwave field, and the activation energy is reduced by about 30% (corresponding to the yield from 47.6% to 91.2%). However, the ordinary MoS2 catalyst in Comparative Example 3 lacks the acidic sites of HZSM-5 molecular sieve, and cannot achieve the synergistic path of butadiene protonation and sulfur atom activation, resulting in a 23% decrease in selectivity (from 96.5% to 73.8%), further confirming the necessity of the "acid-sulfur" dual site of the core-shell structure.

[0062] In addition, the choice of dispersion medium directly affects the stability of sulfur nanoparticles. In Comparative Example 7, water molecules participate in the side reaction to generate thiothiophene (selectivity is only 65.4%), and sulfur is severely agglomerated (D50=500nm) due to the lack of sulfur-repelling protection of ionic liquid [BMIM]PF6, and the reaction activity is greatly reduced. In contrast, in Example 1, ionic liquids and graphene quantum dots (GQDs) stabilize the sulfur dispersion system through π-π interaction, ensuring the uniform distribution of nanoparticles throughout the reaction, and the sulfur residue is only 0.8% (Comparative Example 7 is 18.7%). This result is completely consistent with the theory of "ionic liquid-GQDs coordinated dispersion" in the previous mechanism.

[0063] In summary, the coordinated design of sulfur nano-sizing and core-shell catalysts, combined with the stability control of ionic liquid dispersion systems, is the key to breaking through the limitations of traditional high-temperature processes and achieving efficient and clean production. Experiment 2: Microwave-microchannel low-temperature catalytic performance verification Experimental Description Experimental purpose: To verify the synergistic effect of microwave field and microchannel structure on low-temperature reaction energy consumption, coking inhibition and mass transfer efficiency.

[0064] Experimental steps: Reaction system construction: Example 1: Microwave-microchannel reactor (single channel diameter 180 μm), microwave power dynamically adjusted (1-5 kW), reaction temperature 250°C; Comparative Example 2: conventional tubular reactor (33 mm diameter), electrically heated to 250 °C, without microwave input; Comparative Example 6: Microwave-microchannel reactor, but the reaction temperature was increased to 300°C.

[0065] Raw material handling: All groups used the same pretreated butadiene (H2O≤10ppm, O2≤50ppm) and sulfur nanoslurry (D50=80nm, concentration 32%).

[0066] Reaction run: Example 1: Dynamic adjustment of microwave power (initial 5 kW, middle reaction stage 3 kW, final stage 1 kW), pressure 0.12 MPa, residence time 25 seconds; Comparative Example 2: Constant temperature electric heating, pressure 0.12 MPa, residence time 25 seconds; Comparative Example 6: The microwave power was fixed at 5 kW, the pressure was 0.15 MPa, and the residence time was 35 seconds.

[0067] Data collection: Real-time monitoring of energy consumption (electricity meter recording) and reactor wall temperature distribution (infrared thermal imaging); After the operation cycle is completed, the coke on the inner wall of the reactor is scraped and weighed; GC-MS was used to analyze the content of unreacted butadiene and by-products in the product.

[0068] The experimental data are shown in Table 2 Table 2: Data table of the effects of microwave field and reaction temperature on catalytic performance Experimental Summary This experiment revealed the unique advantages of the microwave-microchannel system in low-temperature reactions by comparing the dynamic regulation of the microwave field with the traditional heating mode. The microwave frequency (2.50GHz) is highly matched with the dielectric loss characteristics of the MoS2 shell in the core-shell catalyst, inducing local hot spots (transient temperature > 300°C), while the overall temperature of the system only needs to be 250°C, which is 45% energy-saving compared to traditional electric heating (Comparative Example 2). The local high-temperature area is quickly dissipated through the rapid mass transfer of the microchannel, avoiding the thermal polymerization of butadiene caused by continuous high temperature (by-products dropped from 12.4% to 1.8%), confirming the mechanism of "microwave selective heating-microchannel mass transfer synergy".

[0069] In Comparative Example 6, the reaction temperature was increased to 300°C. Although the residence time was shortened (35 seconds → 25 seconds), the microwave power was fixed at 5kW, resulting in excessive concentration of energy at the reactor inlet, causing the local temperature to soar to above 400°C, triggering the thermal decomposition of sulfur to generate H2S (7.5% by-product), and the laminar shear force in the microchannel was insufficient to offset the disordered molecular motion caused by high temperature, causing the coking rate (2.93g / h) to surge 24 times compared with Example 1 (0.12g / h). This result is consistent with the description of "homogenizing effect of microchannel structure on temperature gradient" in the mechanism, proving that low temperature (180-250°C) is the key to maintaining efficient mass transfer and low coking.

[0070] In addition, dynamic microwave power regulation (5kW→1kW) matched the energy input in the late stage of the reaction with the reaction exothermic rate, and the unreacted butadiene content was reduced from 18.6% in Comparative Example 2 to 2.3%. However, due to the inability to adjust the heat source in real time in conventional electric heating (Comparative Example 2), the reactor outlet temperature fluctuated by ±15°C, resulting in unstable butadiene conversion (yield fluctuation>10%).

[0071] Experiment 3: Sulfur cycle and environmental performance verification Experimental Description Experimental purpose: To verify the effect of Claus sulfur cycle system on resource utilization, by-product control and environmental compliance.

[0072] Experimental steps: Reaction system configuration: Example 1: Claus reactor temperature 260°C, TiO2 / Al2O3 catalyst (TiO2 loading 15%), sulfur nanoparticle system turned on; Comparative Example 4: The Claus reactor and the sulfur nano-processing system were shut down, and H2S was directly incinerated; Comparative Example 9: The temperature of the Claus reactor was 200° C., and other conditions were the same as those in Example 1.

[0073] Raw materials and operation: All groups used the same reaction product gas (H2S concentration 12 vol%), and the sulfur nano-slurry circulation rate was set to 80% of that in Example 1; Example 1 and Comparative Example 9: Claus reactor operating pressure 0.05 MPa, residence time 2 minutes; Comparative Example 4: H2S was introduced into the incinerator (temperature 800°C, excess air coefficient 1.2).

[0074] Data collection: Online gas phase analyzer monitors the concentration of H2S and SO2 in the exhaust gas; Take samples of sulfur slurry at the outlet of the sulfur condenser to test the sulfur particle size (D50) and impurity content; Calculate the sulfur consumption and wastewater treatment cost (only Example 4 needs to treat sulfur-containing wastewater).

[0075] The experimental data are shown in Table 3. Table 3: Data table on the impact of sulfur cycle system on resource utilization and emissions * Note: Comparative Example 9 requires additional desulfurization treatment due to thiosulfate impurities, which increases costs.

[0076] Experimental Summary This experiment reveals the dual value of closed-loop recovery of sulfur resources for environmental protection and cost by comparing the opening and closing and temperature control of the Claus sulfur circulation system. When the Claus reactor temperature is maintained at 260°C (Example 1), a highly active Ti-S bond is formed on the surface of the TiO2 / Al2O3 catalyst, which promotes the path selectivity of H2S oxidation to elemental sulfur>95%, the sulfur recovery rate is as high as 97.6%, and the tail gas SO2 emission is only 8.3ppm (far below the environmental protection limit of 50ppm). In Comparative Example 9, the reaction temperature dropped to 200°C, and the proportion of sulfate species (Ti-O-SO3) on the catalyst surface increased to 40%, resulting in a sharp drop in the H2S conversion rate to 64.8%, and the unreacted H2S was further oxidized to generate SO2 (38.9ppm), while thiosulfate (2350ppm) was produced as a by-product, requiring additional chemical precipitation treatment, and the cost increased by US$52.7 / ton, confirming the strong correlation between "Claus temperature-catalyst activity-sulfur form conversion".

[0077] In Comparative Example 4, H2S is directly incinerated, which simplifies the process, but completely wastes sulfur resources (the unit consumption increases from 75.2 parts to 112.4 parts), and SO2 emissions exceed the standard by 10 times (523.7ppm), requiring a wet desulfurization device (cost of $84.5 / ton), which runs counter to the "near-zero sulfur emission" goal of the present invention. Experimental data further show that the sulfur nano-system is crucial for the recycling of recovered sulfur: in Example 1, the condensed sulfur is crushed by airflow with D50=82nm, and can be directly returned to the reaction system, while in Comparative Example 9, the low-temperature condensed sulfur agglomerates (D50=280nm), requiring secondary crushing, which increases energy consumption by 15%.

[0078] In summary, the coordinated design of the Claus cycle system and sulfur nano-crystallization not only achieves efficient reuse of sulfur resources (recovery rate > 97%), but also suppresses the formation of by-products through precise temperature control, solving the problem of coexistence of sulfur waste and pollution in traditional processes.

[0079] Experiment 4: Verification of molecular sieve membrane separation efficiency Experimental Description Experimental purpose: To verify the core role of molecular sieve membranes in improving thiophene purity, reducing wastewater emissions and sensitivity to operating parameters.

[0080] Experimental steps: Separation system construction: Example 2: MFI type molecular sieve membrane (pore size 0.55 nm), transmembrane pressure difference 0.3 bar, operating temperature 70°C; Comparative Example 5: The molecular sieve membrane was eliminated and water washing separation was adopted (water / thiophene volume ratio = 3:1, stirring speed 200 rpm); Comparative Example 8: MFI type molecular sieve membrane, the transmembrane pressure difference is increased to 1.0 bar, and other conditions are the same as in Example 2.

[0081] Feed preparation: All groups used the same reaction crude product (thiophene content 85%, dithiophene 10%, thiothiophene 5%), and the feed flow rate was 50 L / h.

[0082] Separation operation: Example 2: The membrane module is operated continuously for 24 hours, and samples are taken every 4 hours to detect purity; Comparative Example 5: After washing with water, the mixture was allowed to stand for stratification and centrifuged (3000 rpm, 10 minutes), and the COD value of the water phase was recorded; Comparative Example 8: The membrane rupture rate was detected every 2 hours under high pressure operation.

[0083] Data collection: GC analysis of thiophene purity and impurity content after separation; COD analyzer detects the concentration of organic matter in wastewater; Physical testing: Example 2 / Comparative Example 8: Membrane integrity was evaluated by transmembrane pressure fluctuation (±5%) and membrane flux decay rate; For Comparative Example 8, leakage of the membrane module was additionally recorded (visual inspection).

[0084] The experimental data are shown in Table 4 Table 4: Molecular sieve membrane separation efficiency and operating parameters influence data table Experimental Summary This experiment reveals the key effects of precise pore size control and transmembrane pressure difference regulation on product purity and environmental friendliness by comparing the performance differences between molecular sieve membrane and water washing separation. The MFI molecular sieve membrane (pore size 0.55nm) selectively intercepts dithiophene with a kinetic diameter of 0.65nm (99.4% purity in Example 2) due to its regular pore structure, while the water washing separation (Comparative Example 5) has a thiophene purity of only 87.3% due to the co-solvent effect of similar polar substances, and produces high COD wastewater (2180mg / L), requiring an additional treatment cost of US$320.7 / ton. This result is completely consistent with the statement in the mechanism that "separation is dominated by the size screening effect of molecular sieve membranes", proving that pore size matching is the core of improving purity.

[0085] In Comparative Example 8, the transmembrane pressure difference was increased to 1.0 bar (outside the range of 0.3-0.5 bar), causing the shear force on the membrane surface to exceed the mechanical strength threshold of the MFI skeleton, and the membrane flux attenuation rate surged from 4.8% in Example 2 to 28.7%. At the same time, the transmembrane pressure difference fluctuation (±15.4%) indicated that the membrane structure was irreversibly damaged (visible local leakage). This phenomenon is consistent with the correlation model of "transmembrane pressure difference-membrane structure stability" in the mechanism, verifying the necessity of low pressure difference and gentle separation. After the membrane was damaged, the permeability of impurities (thiothiophene) increased, the purity dropped from 99.4% to 93.6%, and the operating energy consumption increased to 285.4 kWh / t (105.3 kWh / t in Example 2) due to compensation for leakage losses.

[0086] In addition, the water-free separation characteristics of the molecular sieve membrane (no COD was detected in the wastewater of Example 2) completely avoided the problem of sulfur-containing wastewater in the traditional water washing process (Comparative Example 5, COD>2000mg / L). Although Comparative Example 8 did not directly generate wastewater, it required frequent replacement of components after the membrane ruptured (the cost increased by US$180 / ton), and the comprehensive benefits were still lower than the solution of the present invention.

[0087] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production equipment for synthesizing thiophene by reacting butadiene with sulfur, characterized in that: include: A butadiene treatment mechanism (1) is used for dehydrating and deoxygenating butadiene by molecular sieve adsorption and catalytic deoxygenation; The butadiene processing mechanism (1) comprises a butadiene storage tank (102), the raw material input and output ports of the butadiene storage tank (102) are respectively connected to the input and output ports of the butadiene unloading crane (101) through pipelines, the purification output end of the butadiene storage tank (102) is connected to the adsorption input end of the molecular sieve adsorption tower (103) through a pipeline, the adsorption output end of the molecular sieve adsorption tower (103) is connected to the deoxidation input end of the active copper deoxidation bed (104) through a pipeline, and the deoxidation output end of the active copper deoxidation bed (104) is connected to the reaction mechanism (3) through a pipeline a; A sulfur processing mechanism (2) for preparing sulfur nano-slurry by air flow pulverization and dispersion; The sulfur treatment mechanism (2) comprises a sulfur storage tank (201), the raw material output end of the sulfur storage tank (201) is connected to the pulverization input end of the air flow pulverizer (202) through a pipeline, the pulverization output end of the air flow pulverizer (202) is connected to the slurry input end of the sulfur nano-slurry storage tank (203) through a pipeline, and the pre-treated slurry output end of the sulfur nano-slurry storage tank (203) is connected to the reaction mechanism (3) through a pipeline b; The reaction mechanism (3) is used for the catalytic reaction of butadiene and sulfur and the treatment of the product.

2. The production equipment for synthesizing thiophene by reacting butadiene with sulfur according to claim 1, characterized in that: The reaction mechanism (3) comprises a high-pressure atomizing nozzle (301), a first feed end and a second feed end of the high-pressure atomizing nozzle (301) are connected to a pipeline a and a pipeline b respectively, an atomizing output end of the high-pressure atomizing nozzle (301) is connected to a reactant input end of a microwave-microchannel reactor (302) via a pipeline, a reactant output end of the microwave-microchannel reactor (302) is connected to a separation input end of a gas-liquid separator (303) via a pipeline, a liquid phase output end of the gas-liquid separator (303) is connected to a membrane feed end of a molecular sieve membrane separator (308) via a pipeline, and a membrane product output end of the molecular sieve membrane separator (308) is connected to a distillation tower (309) via a pipeline. The first and second sulfur condensers (305) are connected to the first and second sulfur condensers (306) through a pipeline, the second sulfur condenser (306) is connected to the first and second sulfur condensers (307) through a pipeline, the second sulfur condenser (305) is connected to the second and third sulfur condensers (307) through a pipeline, the second sulfur condenser (306) is connected to the second and third sulfur condensers (307) through a pipeline, the second sulfur condenser (305) is connected to the second and third sulfur condensers (306) through a pipeline, the second sulfur condenser (306) is connected to the second and third sulfur condensers (307) through a pipeline, the second sulfur condenser (305 ...

3. A production process for synthesizing thiophene by reacting butadiene with sulfur, applied to the production equipment for synthesizing thiophene by reacting butadiene with sulfur as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: S1, subjecting the butadiene raw material to molecular sieve adsorption dehydration and copper-based catalytic deoxidation treatment in sequence to obtain purified butadiene, and transporting the purified butadiene to a reaction mechanism (3); S2, dispersing the sulfur raw material in the ionic liquid after air flow pulverization to form sulfur nano-slurry, and transporting the sulfur nano-slurry to the reaction mechanism (3); S3, mixing the purified butadiene with the sulfur nano-slurry and inputting the mixture into a microwave microchannel reactor for catalytic reaction to generate a thiophene-containing product; S4, separating the reaction product by gas-liquid separation, separating and purifying the liquid product by molecular sieve membrane to obtain crude thiophene, and converting the gas product by hydrogen sulfide reaction to recover sulfur; S5, returning the recovered sulfur to the sulfur nano-slurry preparation step for recycling after nano-processing.

4. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The microwave frequency of the microwave-microchannel reactor (302) is 2.40 GHz to 2.50 GHz, and the dynamic adjustment range of microwave power is 1 kW to 5 kW. The inner wall of the microwave-microchannel reactor (302) is loaded with a core-shell structure catalyst, and the core-shell structure catalyst comprises a molecular sieve core and a molybdenum sulfide shell layer.

5. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 4, characterized in that: The inner core of the molecular sieve is a HZSM-5 molecular sieve with a silicon-aluminum molar ratio of 20:1 to 30:

1. The thickness of the molybdenum sulfide shell layer is 5nm to 8nm and is grown on the surface of the molecular sieve by an atomic layer deposition process.

6. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The particle size distribution of the sulfur particles in the sulfur nano-slurry satisfies that D50 is 80nm to 100nm, D90 is no more than 150nm, the sulfur mass concentration is 28% to 32%, the dispersion medium is 1-butyl-3-methylimidazole hexafluorophosphate ionic liquid, and graphene quantum dots are added as a dispersion stabilizer, and the addition amount of the graphene quantum dots is 0.05% to 0.15% of the sulfur mass.

7. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The molecular sieve membrane used in the molecular sieve membrane separation and purification is an MFI type molecular sieve membrane with a pore size of 0.54 nm to 0.56 nm, an operating temperature of 70° C. to 90° C., and a transmembrane pressure difference of 0.3 bar to 0.5 bar.

8. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The hydrogen sulfide conversion reaction is carried out in a Claus reactor (304) at a reaction temperature of 240°C to 260°C. The catalyst is titanium dioxide-supported alumina, and the mass loading of titanium dioxide is 10% to 15%.

9. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The sulfur nano-treatment adopts an air flow pulverization process with a pulverization pressure of 0.6 MPa to 0.8 MPa. The particle size D50 of the pulverized sulfur particles is 80 nm to 100 nm, and the ionic liquid is used to disperse the sulphur to form a circulating slurry.

10. The process for synthesizing thiophene by reacting butadiene with sulfur according to claim 3, characterized in that: The conditions of the catalytic reaction are reaction temperature of 180° C. to 250° C., system pressure of 0.08 MPa to 0.12 MPa, and material residence time of 25 seconds to 35 seconds.

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