Device for continuously rectifying and purifying sulfur and sulfur rectifying tower

Abstract

The utility model provides a device and a rectifying tower for continuous rectification purification of sulphur, the device comprises a first preheater, a rectifying tower, a condenser and a vacuum unit, the first preheater is used for preheating crude liquid sulphur, the temperature of the crude liquid sulphur is preheated to 280-380 DEG C, the rectifying tower comprises a tower body, and the condenser is arranged in the tower body. The tower body sequentially comprises a tower top, a rectifying section, a stripping section and a tower kettle from top to bottom, preheated crude liquid sulfur enters the rectifying tower through a feeding hole, and the rectifying section is provided with a side line extraction hole; the condenser is communicated with the gas phase outlet to condense light components rich in gas sulfur, condensate rich in liquid sulfur obtained after condensation of the condenser enters the rectifying section through the reflux inlet, the cooling medium is 100-150 DEG C, and the condensate rich in liquid sulfur is output by the condenser; and the vacuum unit is used for providing a vacuum environment of-80 to-95 kpa for the rectifying tower.

Description

Technical Field

[0001] The utility model relates to sulfur purification, in particular to a device for continuous distillation and purification of sulfur and a sulfur distillation tower. Background Art

[0002] Sulfur is a non-metallic element with the chemical symbol S and the atomic number 16. Usually, elemental sulfur is a yellow crystal, also known as sulfur. There are many allotropes of elemental sulfur, including orthorhombic sulfur, monoclinic sulfur and elastic sulfur. The main use of sulfur is to make sulfur compounds, such as sulfuric acid, sulfites, thiosulfates, thiocyanates, sulfur dioxide, carbon disulfide, disulfur dichloride, trichlorothiophosphorus, phosphorus sulfides and metal sulfides. The sulfur consumed in the world to make sulfuric acid each year accounts for more than 80% of the total annual consumption of sulfur. Sulfur is also used in large quantities to produce vulcanized rubber. After raw rubber is vulcanized into vulcanized rubber, it has the advantages of high elasticity, heat resistance, tensile strength and insolubility in organic solvents. Most rubber products are vulcanized rubber, which is made by reacting raw rubber with sulfur and accelerators at a certain temperature and pressure. Sulfur is also needed to make black powder and matches. It is also one of the main raw materials for the production of fireworks. Sulfur can also be used in the production of sulfur dyes and pigments. For example, a mixture of kaolin, pure carbon, sulfur, diatomaceous earth or quartz powder can be calcined to produce a blue pigment, group blue. The bleaching industry and the pharmaceutical industry also consume some sulfur. In medicine, sulfur is one of the ingredients of many ointments for treating skin diseases. For example, tung oil and sulfur are heated together, sulfonated with sulfuric acid and neutralized with ammonia water to obtain tung oil. It is used to make a 10% ointment, which has the effect of reducing inflammation and swelling, and can be used to treat various skin inflammations and swelling and pain.

[0003] At present, wet oxidation desulfurization technology is used in the treatment of coke oven gas in domestic coking plants and associated gas of some oil and gas field enterprises. H2S in coke oven gas or associated gas is oxidized into elemental sulfur and discharged from the desulfurization unit in the form of sulfur foam. There are several ways to treat sulfur foam: (1) Entering the sulfur foam centrifuge or filter press, the product is a water-containing sulfur paste with a sulfur content of 30% to 55%, which is a waste solid in the factory and has a bad environment. (2) Entering the sulfur melting kettle. The purity of the liquid sulfur at the bottom outlet of the sulfur melting kettle is about 88%. It cannot meet the requirements of the national standard for sulfur, is still a waste solid, has no economic value, and has a high environmental risk. (3) Entering the sulfur foam acid production unit, the sulfur foam liquid is treated and incinerated and converted into sulfuric acid, but the sulfur foam acid production unit has a large investment, a long process, high energy consumption, and the acid production unit produces a large amount of waste acid and the quality of concentrated sulfuric acid is also unstable. In view of this, a sulfur purification process is adopted to increase the sulfur purity to more than 99%, meeting the requirements of the national sulfur standard GBT 2449.1-2021, and can be sold as a product. This can not only solve environmental problems, but also generate certain economic value.

[0004] There are several sulfur refining processes in China: (1) Diatomaceous earth filtration method: After the sulfur foam is heated and separated in a molten sulfur kettle, it is filtered and further purified by a diatomaceous earth filter. However, the product produced by this technology still cannot reach a purity of more than 99%, and the on-site operating environment of the diatomaceous earth filter is harsh and labor-intensive. There are basically no cases of normal use in China. (2) "Heaven and Earth Pot" boiling method: This method is the most traditional. It uses a normal pressure intermittent distillation process. The intermittent distillation process is a common distillation technology for separating liquid mixtures, also known as batch distillation. It is widely used in practice in the fields of chemical industry, petroleum and brewing. The basic principle of this method is to use the difference in boiling points between different components, heat the mixture by controlling the temperature to evaporate it, and re-condense it into a liquid in the condenser to achieve separation. Compared with the continuous distillation method, the main feature of the intermittent distillation method is that it can process a limited amount of mixture within a period of time. Due to the high boiling point of sulfur, the intermittent distillation temperature is controlled at above 450°C, which causes the equipment to alternate between hot and cold operation and produce alternating loads, making it impossible to use for a long time. In addition, due to its intermittent production of one kettle at a time, it cannot be automated, so the product scale is small and the quality is unstable. In addition, the energy consumption of intermittent distillation is high. For example, CN115180596A discloses a method and equipment for continuously refining and purifying sulfur from crude sulfur. A method for continuously refining and purifying sulfur from crude sulfur includes the following steps: (1) melting sulfur: first put part of the crude sulfur into the sulfur melting kettle, start stirring while heating, and then slowly put in the remaining crude sulfur, and control the process temperature at 110-151°C; (2) stop stirring after filtering the sulfur melting, and send the liquid sulfur to the sulfur filter for filtration. The filtered liquid sulfur flows to the liquid sulfur storage tank for insulation and temporary storage under the action of gravity; (3) heat the liquid sulfur in the liquid sulfur storage tank to the first heating kettle and heat it to 215-225°C, and then The sulfur flows from the top overflow port of the first heating kettle to the second heating kettle to be heated to 265-275°C, then flows from the top overflow port of the second heating kettle to the third heating kettle to be heated to 315-400°C, then flows from the top overflow port of the third heating kettle to the distillation kettle; (4) Distillation: The temperature of the distillation kettle is controlled at 440-450°C to distill the liquid sulfur, and the extracted sulfur vapor is used as a heating medium to be successively passed into the third heating kettle, the second heating kettle and the first heating kettle for heat exchange, and then sent to the condenser; (5) The condensed sulfur vapor is condensed into liquid sulfur at 150-180°C in the condenser, and then transported to the finished sulfur collection tank for collection. This purification process has extremely high energy consumption. (3) Organic solvent extraction method: introduce organic solvents such as CS2, C2HC13, CCl4 to extract sulfur and then crystallize it. This process has the characteristics of high toxicity, high volatility, flammability and explosiveness of organic solvents. At the same time, the process is complicated, the primary yield of sulfur is not high, and the production cost is high. Utility Model Content

[0005] In a first aspect, the utility model provides a device for continuous distillation and purification of sulfur, the device comprising:

[0006] A first preheater, the first preheater is used to preheat the crude liquid sulfur to a temperature of 280-380° C.;

[0007] A distillation tower, the distillation tower comprises a tower body, the tower body comprises a tower top, a distillation section, a stripping section and a tower bottom in order from top to bottom, the tower body is provided with a feed inlet at the tower wall above the stripping section and below the distillation section, and the preheated crude liquid sulfur enters the distillation tower through the feed inlet; the tower top is provided with a gas phase discharge outlet, and the bottom of the tower bottom is provided with a heavy component discharge outlet; the tower body is provided with a reflux liquid inlet above the distillation section, and the distillation section is provided with a side line production outlet;

[0008] A condenser, the condenser is connected to the gas phase discharge port to condense the light components rich in gaseous sulfur, the condensate rich in liquid sulfur obtained after condensation by the condenser enters the distillation section through the reflux liquid inlet, the cooling medium is 100-150° C., and the output of the condenser is a condensate rich in liquid sulfur;

[0009] A vacuum unit is used to provide a vacuum environment of -80 to -95 kPa for the distillation tower.

[0010] The crude liquid sulfur is purified by the above continuous distillation device. The distillation and purification under reduced pressure can effectively reduce the operating temperature. Compared with intermittent distillation which requires high temperature operation (usually above 450°C), continuous distillation can reduce the process temperature to the range of 280-380°C, thereby greatly reducing production energy consumption. Secondly, continuous distillation can realize continuous automated production, and this continuity can also improve production efficiency and product stability. In addition, it is easier to control the purity of sulfur purification using a continuous distillation device. By adjusting operating parameters such as the reflux ratio and the height of the distillation section, the purity of sulfur can be more accurately controlled, and the use of this process can achieve a sulfur purity of more than 99%.

[0011] In some examples, the utility model provides a process for continuous distillation and purification of sulfur, which process includes the following steps: 1) preheating the crude liquid sulfur to be purified to 280-380°C; 2) the preheated crude liquid sulfur enters a distillation tower for vacuum distillation, and the vacuum degree of the distillation tower is maintained at -80--95kpa, and part of the liquid at the bottom of the distillation tower is reboiled by heating, and the sulfur-containing steam from bottom to top contacts the crude liquid sulfur in countercurrent to cause mass transfer and heat transfer; wherein, the boiling point of liquid sulfur under normal pressure is about 450°C, and when the vacuum degree of the distillation tower is -80--95kpa, the boiling point of liquid sulfur can be reduced to 280-380°C. The crude liquid sulfur is preheated to 280-380°C and then enters the distillation tower to facilitate the gasification of the liquid sulfur; 3) High-purity liquid sulfur is extracted from the side line of the distillation tower, and the sulfur-containing gas phase flows out from the top of the tower and is condensed into a sulfur-containing condensate by the condenser and then refluxed to the distillation tower, and the heavy components are discharged from the bottom of the distillation tower.

[0012] In some embodiments, the tower bottom is provided with a reboiler to heat the liquid at the bottom of the tower bottom.

[0013] Sulfur is a flammable and explosive substance. When exposed to high temperature or oxygen, it is easy to spontaneously combust or explode. In some embodiments, the distillation tower is provided with a gas inlet to provide an inert environment for vacuum distillation; preferably nitrogen or argon. By delivering an inert gas to the distillation tower, the oxygen content in the system can be reduced, thereby creating a low-oxygen environment and reducing the risk of sulfur explosion. This practice of using an inert atmosphere to protect the sulfur purification process can increase safety and ensure that no accidents occur during the distillation process. Therefore, using an inert gas as a protective atmosphere can effectively reduce these risks. In some embodiments, the tower bottom is provided with a gas inlet, and the gas inlet is used to introduce an inert gas. Exemplarily, in some embodiments, the inert gas is nitrogen or argon.

[0014] In some embodiments, the distillation tower includes a distillation section and a stripping section; the theoretical plate number of the stripping section is not less than 6, preferably not less than 8, and more preferably not less than 10; the theoretical plate number of the distillation section is not less than 4, preferably not less than 6, and more preferably not less than 8.

[0015] In some embodiments, the rectifying section and the stripping section are equipped with metal fillers.

[0016] In some embodiments, the side line outlet of the distillation tower is located at a lower position of the distillation section; preferably, the side line outlet is located 1.2 to 1.5 m below the packing layer of the distillation section.

[0017] In some embodiments, the condenser is a shell-and-tube condenser. Preferably, the tube-side inlet of the shell-and-tube condenser is connected to the gas phase outlet, the tube-side liquid phase outlet is connected to the liquid sulfur product tank A, the tube-side gas phase outlet is connected to the vacuum unit, the shell-side inlet of the condenser is connected to the cooling medium pipeline, the shell-side outlet of the condenser is connected to the steam pipeline, and the steam pipeline is provided with a regulating valve.

[0018] In some embodiments, the condenser is connected to the product tank A to collect condensate rich in liquid sulfur, and the product tank A is connected to the reflux liquid inlet through a reflux pump; preferably, a gas-liquid separation unit is provided at the end of the condenser, and the gas-liquid separation unit is connected to the product tank A through a sulfur sealing tank, and the product tank A is connected to the reflux liquid inlet through a reflux pump.

[0019] In some embodiments, the device further includes a desalination unit connected upstream of the first preheater, the desalination unit including a static mixer and an electric desalter, the static mixer being connected to the electric desalter, and the static mixer being used to mix the demulsifier with the crude liquid sulfur. The crude liquid sulfur contains impurity salts such as ammonium thiocyanate, ammonium thiosulfate, and ammonium sulfate. The presence of impurity salts reduces the purity of the liquid sulfur. During the distillation process, impurity salts such as ammonium thiocyanate, ammonium thiosulfate, and ammonium sulfate may decompose or react to produce other compounds, thereby causing the purity of the liquid sulfur to decrease. The presence of impurity salts may cause interference and blockage inside the distillation tower, increasing the energy consumption during the distillation process. The deposition and crystallization of impurity salts will adhere to the surface of the distillation tower, reducing the heat and mass transfer efficiency, thereby requiring higher energy to complete the purification process. The crystallization of impurity salts may block the pipes and devices of the distillation tower, resulting in interruption and failure of the equipment. The formation of crystals may also cause pressure changes, affect the strength and stability of the equipment, and even lead to the risk of equipment rupture or explosion. If impure salts enter the distillation tower, the maintenance and cleaning costs of the equipment will increase. It is necessary to shut down for maintenance, remove crystals and sediments, and the equipment may need to be cleaned and maintained more frequently to ensure normal operation. Based on this, the utility model uses an electric desalting tank to perform desalination pretreatment on the crude liquid sulfur before vacuum distillation of the crude liquid sulfur. In some preferred embodiments, the desalting pretreatment includes the following steps: the crude liquid sulfur heated to 130°C to 150°C is mixed with a demulsifier through a static mixer and then enters the electric desalting tank for desalination. This embodiment uses electric desalting to remove impurity salts from crude liquid sulfur and prevents impurity salts from entering the distillation tower, which can improve the purity of liquid sulfur, reduce energy consumption and equipment damage risks, and reduce maintenance and cleaning costs.

[0020] In some embodiments, the vacuum unit is connected downstream of the condenser to draw the gas phase in the distillation tower and the condenser to form a negative pressure and maintain the vacuum degree at -80 to -95 kPa. In some specific embodiments, the vacuum unit includes a vacuum water tank, a circulating water pump, a vacuum ejector, and an attached pipeline valve.

[0021] In some embodiments, a reflux liquid distributor for distributing reflux liquid and / or a liquid distributor for distributing feed liquid is provided in the distillation tower.

[0022] In the second aspect, the utility model provides a sulfur distillation tower, which includes a tower body, which includes a tower top, a distillation section, a stripping section and a tower bottom from top to bottom. The tower body is provided with a feed inlet on the tower wall above the stripping section and below the distillation section, and the preheated crude liquid sulfur enters the distillation tower through the feed inlet; the tower top is provided with a gas phase discharge outlet, and the bottom of the tower bottom is provided with a heavy component discharge outlet; the tower body is provided with a reflux liquid inlet above the distillation section, and the distillation section is provided with a side line production outlet.

[0023] In some embodiments, a reboiler is provided at the bottom of the tower kettle to heat the liquid at the bottom of the tower kettle.

[0024] In some embodiments, the tower bottom is provided with a gas inlet, and the gas inlet is used to introduce an inert gas.

[0025] In some embodiments, the theoretical plate number of the stripping section is not less than 6, preferably not less than 8, and more preferably not less than 10; the theoretical plate number of the rectifying section is not less than 4, preferably not less than 6, and more preferably not less than 8.

[0026] In some embodiments, the rectifying section and the stripping section are equipped with metal fillers.

[0027] In some embodiments, the condenser is a shell and tube condenser.

[0028] In some embodiments, the side line outlet of the distillation tower is located at a lower position of the distillation section; in some specific embodiments, the side line outlet is located 1.2 to 1.5 m below the packing layer of the distillation section.

[0029] In some embodiments, a reflux liquid distributor for distributing reflux liquid and / or a liquid distributor for distributing feed liquid is provided in the distillation tower.

[0030] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 A flow chart of the continuous distillation process provided by the utility model;

[0033] Figure 2 A structural schematic diagram of a distillation device is provided for the utility model;

[0034] Figure 3-Figure 5 It is an enlarged view of the A part, B part and C part of the distillation device provided by the utility model;

[0035] Figure 6 The utility model is a structural cross-sectional view of a distillation tower.

[0036] in;

[0037] 1-distillation tower; 2-first preheater; 3-second preheater; 4-vacuum unit; 5-condenser; 6-electric desalting tank; 7-raw material buffer tank; 8-static mixer; 9-emulsifier pump; 10-reboiler; 11-side line outlet; 12-reflux liquid inlet; 13-feed inlet; 14-gas phase outlet; 15-heavy component outlet; 100-product tank A; 200-product tank B; 51-tube side inlet; 52-tube side liquid phase outlet; 53-tube side gas phase outlet; 55-steam condensate or deoxygenated water; 56-shell side outlet; 131-crude liquid sulfur distributor; 16-distillation section; 17-stripping section; 18-tower bottom; 19-tower top. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left” and “right” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Based on this, the utility model provides a unit with high automation and continuous operation, and has the characteristics of low investment, small footprint, low energy consumption and environmental friendliness, and can refine waste sulfur paste into more than 99% pure sulfur.

[0042] The embodiment of the utility model relates to a crude liquid sulfur purification process, wherein the crude liquid sulfur is a sulfur-containing mixture, and the crude liquid sulfur needs to be further processed and purified to obtain high-purity sulfur. Exemplarily, the crude liquid sulfur is crude liquid sulfur from a wet desulfurization sulfur melting kettle, and the crude liquid sulfur contains sodium salt, ammonium salt and tar.

[0043] See also Figure 2-Figure 6 This embodiment provides a continuous distillation device, which includes a desalination unit, a first preheater 2, a distillation tower 1, a reboiler 10, a condenser 5 and a vacuum unit 4.

[0044] The desalination unit is connected upstream of the first preheater 2 , and the desalination unit comprises a static mixer 8 and an electric desalination tank 6 . The static mixer 8 is communicated with the electric desalination tank 6 , and the static mixer 8 is used to mix the demulsifier and the crude liquid sulfur.

[0045] The first preheater 2 is used to preheat the crude liquid sulfur to a temperature of 280-380°C.

[0046] See also Figure 6The distillation tower 1 includes a tower body, which includes a tower top 19, a distillation section 16, a stripping section 17 and a tower bottom 18 from top to bottom. The tower body is provided with a feed port 13 at the tower wall above the stripping section 17 and below the distillation section 16, and the preheated crude liquid sulfur enters the distillation tower 1 through the feed port 13; the tower top 19 is provided with a gas phase discharge port 14, and the bottom of the tower bottom 18 is provided with a heavy component discharge port 15; the tower body is provided with a reflux liquid inlet 12 above the distillation section 16, and the distillation section 16 is provided with a side line production port 11; the condenser 5 is connected to the gas phase discharge port 14 to condense the light component rich in gas sulfur, and the condensate obtained after condensation by the condenser 5 enters the distillation section 16 through the reflux liquid inlet 12, the cooling medium is 100-150°C, and the condensate rich in liquid sulfur is transported by the condenser 5; the vacuum unit 4 is used to provide a vacuum environment of -80 to -95 kPa for the distillation tower 1. The tower bottom 18 is provided with a reboiler 10 to heat the liquid at the bottom of the tower bottom 18 .

[0047] The tower bottom 18 is provided with a gas inlet, and the gas inlet is used to introduce an inert gas; the inert gas is nitrogen or argon, and the inert gas is preferably heated by a second preheater 3.

[0048] The rectifying section 16 and the stripping section 17 are packed towers; both the rectifying section 16 and the stripping section 17 are filled with metal fillers. Exemplarily, the number of theoretical plates of the stripping section 17 is 12; the number of theoretical plates of the rectifying section 16 is 8.

[0049] The side line outlet 11 of the distillation tower 1 is located at a lower position of the distillation section 16 . Preferably, the side line outlet is located 1.2 to 1.5 m below the packing layer of the distillation section 16 .

[0050] The condenser 5 is a shell-and-tube condenser 5, the tube-side inlet 51 of the shell-and-tube condenser 5 is connected to the gas phase exhaust port 14, the tube-side liquid phase outlet 52 is connected to the liquid sulfur product tank A 100, the tube-side gas phase outlet 53 is connected to the vacuum unit, the shell-side inlet of the condenser 5 is connected to the cooling medium pipeline, the shell-side outlet of the condenser 5 is connected to the steam pipeline, and the steam pipeline is provided with a regulating valve.

[0051] The condenser 5 is provided with a condensate product tank A100 rich in liquid sulfur, and the product tank A100 is connected to the reflux liquid inlet 12 through a reflux pump; preferably, a gas-liquid separation unit, a sulfur sealing tank, a product tank A100 and a reflux pump are provided downstream of the condenser 5, the gas-liquid separation unit is connected to the product tank A100 through the sulfur sealing tank, and the product tank A100 is connected to the reflux liquid inlet 12 through the reflux pump.

[0052] The vacuum unit 4 is connected to the downstream of the condenser 5 to draw the gas phase in the distillation tower 1 and the condenser 5 to form a negative pressure, and maintain the vacuum degree at -80 to -95 kPa. Preferably, due to the high melting point of sulfur, the sulfur component mixed in the low boiling point gas discharged from the condenser is easy to damage the vacuum pump. Based on this, the vacuum unit 4 selected in this application includes a vacuum water tank, a circulating water pump, a vacuum ejector and an auxiliary pipeline valve. The water in the vacuum water tank is pumped into the vacuum ejector through the circulating water pump to form a negative pressure. There is a tail gas outlet at the top of the vacuum water tank, and the non-condensable gas enters the tail gas pipeline through the tail gas outlet and is discharged outside the boundary area. The vacuum unit 4 is installed downstream of the condenser 5; by placing the vacuum pump after the condenser 5, the condenser 5 can give full play to its cooling and condensing effects. This can improve the efficiency of the condenser 5 and better convert gaseous sulfur into liquid form. Installing the condenser 5 before the vacuum pump can prevent harmful or corrosive substances from entering the vacuum pump, thereby extending the service life of the vacuum pump and reducing maintenance requirements. By connecting the vacuum pump and the condenser 5, non-condensable gases can be better discharged, which helps to maintain the negative pressure condition in the tower and prevents these components from further entering the vacuum pump.

[0053] The distillation tower 1 is provided with a reflux liquid distributor for distributing the reflux liquid and a crude liquid sulfur distributor 131 for distributing the feed liquid.

[0054] The utility model further provides a purification process for crude liquid sulfur, please refer to Figure 1 , including the following steps:

[0055] Step 1) Desalting:

[0056] Crude liquid sulfur contains impurity salts such as ammonium thiocyanate, ammonium thiosulfate, ammonium sulfate, sodium thiocyanate, sodium thiosulfate, and sodium sulfate. The presence of impurity salts will reduce the purity of liquid sulfur. During the distillation process, impurity salts may decompose or react to produce other compounds, resulting in a decrease in the purity of liquid sulfur. The presence of impurity salts will cause interference and blockage inside the distillation tower 1, increasing the energy consumption during the distillation process. The deposition and crystallization of impurity salts will adhere to the surface of the distillation tower 1, reducing the heat transfer and mass transfer efficiency, thereby requiring higher energy to complete the purification process. The crystallization of impurity salts may block the pipes and devices of the distillation tower 1, resulting in interruptions and failures in the operation of the equipment. The formation of crystals may also cause pressure changes, affect the strength and stability of the equipment, and even lead to the risk of equipment rupture or explosion. If impurity salts enter the distillation tower 1, the maintenance and cleaning costs of the equipment will increase. It is necessary to shut down for maintenance, remove crystals and sediments, and more frequent cleaning and maintenance of the equipment may be required to ensure normal operation.

[0057] Based on this, the present embodiment provides a desalting pretreatment of crude liquid sulfur before the continuous distillation process, and the device used in the desalting pretreatment process includes a demulsifier pump 9, a static mixer 8 and an electric desalting tank 6, and the crude liquid sulfur (purity 80% to 90%) from the wet desulfurization melting kettle is transported to the raw material buffer tank 7 through a pipeline. The melting point of sulfur is about 114°C. Under the condition that the temperature of the crude liquid sulfur is heated to 130°C to 150°C, the crude liquid sulfur is transported to the static mixer 8 by the liquid sulfur delivery pump, and the demulsifier pump 9 transports the demulsifier to the static mixer 8. The demulsifier and the crude liquid sulfur are mixed through the static mixer 8, and the mixed crude liquid sulfur enters the tank from the upper part of the electric desalting tank 6.

[0058] In the electric desalting tank 6, the crude liquid sulfur is evenly distributed into the high-voltage electric field through a distributor to remove salt and water. Under the action of the high-voltage electric field, the tiny water droplets containing salt water in the crude liquid sulfur will gather into large water droplets. Due to the difference in specific gravity between crude sulfur and water, the crude sulfur will sink to the bottom of the tank, while the water will gather at the top of the tank. After separation, the crude sulfur at the bottom of the tank is collected, and the water at the top of the tank is output to the outside of the tank through the drainage collector. In this way, the treatment of the salt water in the crude liquid sulfur is completed in the electric desalting system, and relatively pure crude liquid sulfur is obtained, which can continue to be processed in the next step.

[0059] This embodiment uses electrical desalination to remove impurity salts from crude liquid sulfur, preventing the impurity salts from entering the distillation tower, thereby improving the purity of liquid sulfur, reducing energy consumption and equipment damage risks, and reducing maintenance and cleaning costs.

[0060] Step 2) Preheating of crude liquid sulfur:

[0061] After desalting in step 1), the crude liquid sulfur enters the first preheater 22 for heating through the electric desalting tank 6. The heating power is adjusted so that the temperature of the liquid sulfur at the outlet of the first preheater 2 is 280-380°C. The heated crude liquid sulfur enters the lower middle part of the sulfur distillation tower. In this way, the temperature of the crude liquid sulfur is 320-380°C when it enters the distillation tower. The preheating before the crude liquid sulfur enters the distillation tower 1 is to prepare for the subsequent vacuum distillation process. The purpose of preheating is to make the crude liquid sulfur reach a temperature suitable for gasification at the corresponding vacuum degree, cooperate with the subsequent vacuum distillation, realize the deep separation of the crude liquid sulfur, and obtain the required purity. The boiling point of liquid sulfur under normal pressure is about 450°C. When the vacuum degree of the distillation tower 1 is -80--95kpa, the boiling point of liquid sulfur can be reduced to 280-380°C.

[0062] Step 3) Continuous distillation

[0063] The crude liquid sulfur preheated in step 2) is purified and separated by continuous distillation, and the continuous distillation unit includes a distillation tower 11, a vacuum unit 44, a condenser 55 and a reboiler 10; specifically, the preheated crude liquid sulfur enters the distillation tower 1 for vacuum distillation, and the vacuum degree of the distillation tower 1 is maintained at -80 to -95 kPa. A portion of the liquid at the bottom of the distillation tower 1 is reboiled by heating to generate sulfur-containing vapor from top to bottom, and the sulfur-containing vapor from bottom to top is in countercurrent contact with the crude liquid sulfur to transfer mass and heat; high-purity liquid sulfur is extracted from the side line of the distillation tower 1, and the gas phase rich in gaseous sulfur flows out from the top 19 of the tower and is condensed into a condensate rich in liquid sulfur by the condenser 5, and then refluxed to the distillation tower 1 for further distillation and purification, and the heavy component tar mixture is discharged from the bottom of the distillation tower 1.

[0064] In this embodiment, the liquid at the bottom of the tower kettle 18 is heated by the reboiler 10 to provide steam for vacuum distillation. The flowing steam from bottom to top contacts the crude liquid sulfur entering from the top of the stripping section 17 in reverse direction, and continuously passes through the gaps in the packing layer to carry out vapor-liquid mass transfer and heat transfer. The packing of the stripping section 17 greatly increases the contact area between the gas and liquid phases, thereby enhancing heat and mass transfer. Specifically, the crude liquid sulfur is preheated to 280-380° C. and then enters the distillation tower 1. The reboiler 10 heats the liquid in the tower bottom 18 to evaporate and gasify it. The temperature after gasification is 280-380° C. The high-temperature steam contacts the crude liquid sulfur entering from the top of the stripping section 17 in reverse direction, and mass transfer and heat transfer occur. In this way, the preheated crude liquid sulfur enters the distillation tower 1, and the heavy component impurities in the crude liquid sulfur enter the tower bottom 18, and are pumped out by the tower bottom 18 pump and sent out of the boundary. The light components in the crude liquid sulfur are discharged from the top 19 of the distillation tower 1 and condensed by the condenser 5. The distillation tower 1 has a side line outlet 11. The purity of the liquid sulfur collected from the side line outlet 11 at the upper part of the distillation tower 1 can reach 99.9%. When the crude liquid sulfur reaches the bottom of the tower 18, 99.9% of the sulfur has been gasified and extracted. The heavy impurities in the crude liquid sulfur enter the bottom of the tower 18 and are pumped out by the bottom pump and sent out of the tower. The rising gas phase is discharged from the top of the distillation section 16 and condensed through the condenser 5. The condensate rich in liquid sulfur is collected by gas-liquid separation. The condensate rich in liquid sulfur is refluxed to the distillation section 16 of the distillation tower 1 through a reflux pump for distillation and purification. The purified sulfur liquid is extracted through the side line extraction port 11.

[0065] In some preferred embodiments of the present invention, the distillation tower 1 is provided with an inert gas delivery port to provide an inert environment for vacuum distillation; preferably, high-temperature nitrogen or argon heated by a heater. By delivering inert gas to the distillation tower 1, the oxygen content in the system can be reduced, thereby creating a low-oxygen environment and reducing the risk of sulfur explosion. Specifically, the oxygen density in the system can be monitored and the inert gas can be intermittently opened to enter.

[0066] The utility model adopts a continuous distillation process to purify crude liquid sulfur, and distillation and purification under reduced pressure conditions can effectively reduce the operating temperature. Compared with intermittent distillation which requires high-temperature operation (usually above 450°C), continuous distillation can reduce the process temperature to a range of 280 to 380°C, thereby greatly reducing production energy consumption. Moreover, compared with the intermittent production process, the continuous distillation process can realize continuous automated production, and this continuity can also improve production efficiency and product stability. In addition, the continuous distillation process makes it easier to control the purity of sulfur purification. By adjusting operating parameters, such as the reflux ratio and the height of the distillation section, the purity of sulfur can be more accurately controlled, and the use of this process can achieve a sulfur purity of more than 99%.

[0067] Exemplarily, the sulfur distillation process comprises the following steps:

[0068] i) The vacuum unit 4 draws the gas phase in the distillation tower 1 and the sulfur condenser 5 to form a negative pressure, and maintains the vacuum degree at -80 to -95 kPa. The crude liquid sulfur enters the distillation tower 1 from the feed port 13. A distributor is provided in the distillation tower 1 to evenly distribute the crude liquid sulfur. The reboiler 10 heats the liquid at the bottom of the tower kettle 18, and controls the temperature of the heated gaseous sulfur to flow from bottom to top at 280 to 380°C. The high-temperature steam contacts the crude liquid sulfur entering from the top of the stripping section 17 in reverse direction, and mass and heat transfer are carried out in the packing in the stripping section 17. The packing in the stripping section 17 greatly increases the contact area between the gas and liquid phases, and enhances heat and mass transfer. When the crude liquid sulfur reaches the tower kettle 18, 99.9% of the sulfur has been gasified and extracted, and the heavy component impurities in the crude liquid sulfur enter the tower kettle 18 and are pumped out by the tower kettle 18 pump and sent out of the boundary.

[0069] ii) The light components in the crude liquid sulfur move to the distillation section 16 for further purification. The gaseous sulfur and the refluxed liquid sulfur are countercurrently contacted in the upper distillation section 16 to perform the distillation process. The liquid sulfur is extracted from the side line extraction port 11 in the upper part of the tower, and the purity of the liquid sulfur extracted from the side line can reach 99.9%; the liquid sulfur extracted from the side line enters the liquid sulfur product tank B100 for storage; the gas phase is discharged from the top 19 of the distillation section 16.

[0070] iii) Sulfur condensation

[0071] This embodiment provides a process for condensing gaseous sulfur, which comprises:

[0072] a) providing a shell-and-tube condenser 5, a hot gas flow containing gaseous sulfur to be cooled, and a cooling medium with a temperature of 100-150° C. flowing through the shell side of the shell-and-tube condenser 5; specifically, the tube side inlet 51 of the shell-and-tube condenser 5 is connected to the gas phase discharge port 14 of the rectification tower, the tube side liquid phase outlet 52 is connected to the liquid sulfur product tank A100, the tube side gas phase outlet 53 is connected to the vacuum unit, the shell side inlet of the condenser 5 is connected to the cooling medium pipeline with a temperature of 100-150° C., the shell side outlet of the condenser 5 is connected to the steam pipeline, and the steam pipeline is provided with a regulating valve;

[0073] b) the hot gas stream containing gaseous sulfur enters the tube side inlet 51 of the shell-and-tube condenser 5, and the cooling medium enters the shell side inlet of the shell-and-tube condenser 5;

[0074] c) Liquid sulfur is output from the tube-side outlet of the shell-and-tube condenser 5. Preferably, the by-product steam at the shell-side outlet of the condenser 5 is recycled.

[0075] Specifically, gaseous sulfur is output from the top of the sulfur distillation tower and enters the sulfur condenser 5. The sulfur condenser 5 is a shell-and-tube condenser 5, with sulfur vapor on the tube side, and the cooling medium is steam condensate or deoxygenated water at about 125 to 150°C. The sulfur vapor on the tube side contacts the water on the shell side through the shell-and-tube structure, and the gaseous sulfur is condensed into liquid sulfur using steam condensate or deoxygenated water. The liquid sulfur has low viscosity and high fluidity, which is convenient for liquid sulfur transportation and subsequent operations; if the cooling temperature is too low, the liquid sulfur will solidify into solid sulfur, which will cause pipeline blockage. In addition, if the cooling temperature is too low, light components (such as low-boiling impurities) will also be condensed at the same time and mixed in the liquid sulfur. This may result in a reduction in the purity of the liquid sulfur. Therefore, the present embodiment uses steam condensate so that the gaseous sulfur can be fully condensed into liquid sulfur while maintaining a relatively low viscosity and good fluidity.

[0076] In this process, the condensed water absorbs heat and is converted into water vapor, that is, the sulfur condenser 5 produces byproduct steam. In addition, the byproduct steam can be recovered and utilized, for example, to provide heat or drive other equipment. This can not only increase energy utilization efficiency, but also reduce energy consumption and production costs. In short, condensing gaseous sulfur into liquid sulfur through the shell-and-tube condenser 5 not only makes the sulfur have lower viscosity and high fluidity, which is convenient for subsequent operation and transportation, but also can recover byproduct steam to improve energy utilization efficiency.

[0077] The by-product steam will be discharged from the system through the exhaust port of the shell-and-tube condenser 5. A higher steam pressure will increase the cooling temperature of the condensed water, while a lower steam pressure will reduce the cooling temperature of the condensed water. In this way, the temperature of sulfur condensation is controlled by controlling the steam pressure through the regulating valve to achieve the desired cooling effect and temperature control. In this embodiment, the shell-and-tube condenser 5 is provided with a pressure sensor for detecting the pressure of the cooling medium. The pressure sensor and the regulating valve are connected in communication with the control circuit, and the condensation temperature is controlled by controlling the steam pressure. That is, the sulfur condensation process provided by the utility model produces steam as a by-product, and the sulfur condensation temperature is accurately controlled by controlling the shell-side steam pressure. On the other hand, the heat in the gaseous sulfur is recovered, and a part of steam is produced as a by-product.

[0078] A gas-liquid separation unit is designed at the end of the condenser 5, and the liquid sulfur enters the liquid sulfur product tank A100 from the bottom through the sulfur seal. The gas-liquid separation unit separates the liquid sulfur and the residual gas to ensure that the liquid sulfur with higher purity enters the liquid sulfur product tank A100. The gas-liquid separation unit includes but is not limited to a wire mesh separator, a plate separator, and a rotary separator. The condensed liquid sulfur will enter the liquid sulfur product tank A100 through the lower part of the separation unit, while the gas will be separated and discharged from the outside of the system, ensuring that only pure liquid sulfur exists in the liquid sulfur product tank A100 without gas interference. This helps to ensure the quality and stability of the liquid sulfur, while also meeting safety requirements and preventing gas accumulation from causing potential dangers.

[0079] The liquid sulfur pump transports the liquid sulfur in the liquid sulfur product tank A100 to the sulfur distillation tower as the reflux liquid for distillation, and controls the reflux ratio (the ratio of the reflux flow rate to the top tower mouth flow rate) at 0.8-3. A liquid sulfur flowmeter is provided at the outlet of the liquid sulfur pump. The flowmeter signal is interlocked with the liquid sulfur delivery pump frequency converter, and the liquid sulfur reflux flow rate is adjusted by the frequency converter.

[0080] The final liquid sulfur product is formed into flake or granular sulfur by a liquid sulfur molding machine and then packaged for sale; liquid sulfur has low viscosity and high fluidity at appropriate temperature and can be molded, poured or injection molded by a liquid sulfur molding machine.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate 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 claims and their equivalents.

Claims

1. A device for continuous distillation and purification of sulfur, characterized in that: The device includes: a first preheater, the first preheater being used for preheating crude liquid sulfur; A distillation tower, the distillation tower comprises a tower body, the tower body comprises a tower top, a distillation section, a stripping section and a tower bottom in order from top to bottom, the tower body is provided with a feed inlet at the tower wall above the stripping section and below the distillation section, and the preheated crude liquid sulfur enters the distillation tower through the feed inlet; the tower top is provided with a gas phase discharge outlet, and the bottom of the tower bottom is provided with a heavy component discharge outlet; the tower body is provided with a reflux liquid inlet above the distillation section, and the distillation section is provided with a side line production outlet; A condenser, the condenser is connected to the gas phase discharge port to condense light components rich in gaseous sulfur, and the condensate rich in liquid sulfur obtained after condensation by the condenser enters the distillation section through the reflux liquid inlet; A vacuum unit is used to provide a vacuum environment for the distillation tower.

2. The device according to claim 1, characterized in that The tower kettle is provided with a reboiler to heat the liquid at the bottom of the tower kettle.

3. The device according to claim 1, characterized in that The tower kettle is provided with a gas inlet, and the gas inlet is used to introduce inert gas.

4. The device for continuous distillation and purification of sulfur according to claim 1, characterized in that: The distillation tower comprises a distillation section and a stripping section, and the distillation section and the stripping section are equipped with metal fillers; the number of theoretical plates of the stripping section is not less than 6.

5. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The theoretical plate number of the stripping section is not less than 8.

6. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The theoretical plate number of the stripping section is not less than 10.

7. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The number of theoretical plates of the distillation section is not less than 4.

8. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The number of theoretical plates of the distillation section is not less than 6.

9. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The theoretical plate number of the distillation section is not less than 8.

10. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The rectifying section and the stripping section are equipped with metal fillers.

11. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The side line outlet of the distillation tower is located at the lower part of the distillation section.

12. The device for continuous distillation and purification of sulfur according to claim 4, characterized in that: The side line outlet of the distillation tower is located 1.2 to 1.5 m below the packing layer of the distillation section.

13. The device for continuous distillation and purification of sulfur according to claim 1, characterized in that: The condenser is a shell and tube condenser.

14. The device for continuous distillation and purification of sulfur according to claim 13, characterized in that: The tube side inlet of the shell-and-tube condenser is connected to the gas phase exhaust port, the tube side liquid phase outlet is connected to the liquid sulfur product tank A, the tube side gas phase outlet is connected to the vacuum unit, the shell side inlet of the condenser is connected to the cooling medium pipeline of 100-150°C, the shell side outlet of the condenser is connected to the steam pipeline, and the steam pipeline is provided with a regulating valve.

15. The device for continuous distillation and purification of sulfur according to claim 3, characterized in that: The inert gas is nitrogen or argon.

16. The device for continuous distillation and purification of sulfur according to claim 13, characterized in that: The condenser is connected to the product tank A to collect the condensate rich in liquid sulfur, and the product tank A is connected to the reflux liquid inlet through a reflux pump.

17. The device for continuous distillation and purification of sulfur according to claim 16, characterized in that: A gas-liquid separation unit is provided at the end of the condenser, and the gas-liquid separation unit is connected to the product tank A through a sulfur sealing tank, and the product tank A is connected to the reflux liquid inlet through a reflux pump.

18. The device for continuous distillation and purification of sulfur according to claim 1, characterized in that: The device also includes a desalination unit connected upstream of the first preheater, the desalination unit includes a static mixer and an electric desalination tank, the static mixer is communicated with the electric desalination tank, and the static mixer is used to mix the demulsifier and the crude liquid sulfur.

19. The device for continuous distillation and purification of sulfur according to claim 1, characterized in that: The vacuum unit is connected downstream of the condenser to draw the gas phase in the distillation tower and the condenser to form a negative pressure and maintain the vacuum degree at -80 to -95 kPa.

20. The device for continuous distillation and purification of sulfur according to claim 1, characterized in that: The vacuum unit includes a vacuum water tank, a circulating water pump, a vacuum ejector and associated pipeline valves.

21. The device for continuous distillation and purification of sulfur according to claim 20, characterized in that: The distillation tower is provided with a reflux liquid distributor for distributing the reflux liquid and / or a liquid distributor for distributing the feed liquid.

22. A sulfur distillation tower, characterized in that: The distillation tower comprises a tower body, which comprises a tower top, a distillation section, a stripping section and a tower bottom in order from top to bottom. The tower body is provided with feed ports on the tower wall above the stripping section and below the distillation section, and the preheated crude liquid sulfur enters the distillation tower through the feed ports; the tower top is provided with a gas phase discharge port, and the bottom of the tower bottom is provided with a heavy component discharge port; the tower body is provided with a reflux liquid inlet above the distillation section, and the distillation section is provided with a side line production port.

23. A sulfur distillation tower according to claim 22, characterized in that: The tower kettle is provided with a reboiler to heat the liquid at the bottom of the tower kettle.

24. A sulfur distillation tower according to claim 22, characterized in that: The tower kettle is provided with a gas inlet, and the gas inlet is used to introduce inert gas.

25. A sulfur distillation tower according to claim 22, characterized in that: The theoretical plate number of the stripping section is not less than 6.

26. A sulfur distillation tower according to claim 22, characterized in that: The theoretical plate number of the stripping section is not less than 8.

27. A sulfur distillation tower according to claim 22, characterized in that: The theoretical plate number of the stripping section is not less than 10.

28. A sulfur distillation tower according to claim 22, characterized in that: The number of theoretical plates of the distillation section is not less than 4.

29. A sulfur distillation tower according to claim 22, characterized in that: The number of theoretical plates of the distillation section is not less than 6.

30. A sulfur distillation tower according to claim 22, characterized in that: The number of theoretical plates of the distillation section is not less than 8.

31. A sulfur distillation tower according to claim 22, characterized in that: The rectifying section and the stripping section are equipped with metal fillers.

32. A sulfur distillation tower according to claim 22, characterized in that: The side line outlet of the distillation tower is located at the lower part of the distillation section.

33. A sulfur distillation tower according to claim 22, characterized in that: The side line outlet of the distillation tower is located 1.2 to 1.5 m below the packing layer of the distillation section.

34. A sulfur distillation tower according to claim 22, characterized in that: The distillation tower is provided with a reflux liquid distributor for distributing the reflux liquid and / or a liquid distributor for distributing the feed liquid.

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