阅读说明：本技术 一种氯化亚砜精馏方法 (Thionyl chloride rectification method ) 是由 杨金顺 杨展 朱荣声 王菊花 马铭泽 于 2021-02-25 设计创作，主要内容包括：本发明涉及一种氯化亚砜精馏方法。本发明将下淌至精馏塔底部一氯化硫经立式液下循环泵以大流量进入再沸器加热强制循环,换热升温后的气液(液相为主)混合物上升进入精馏塔下部的提馏段作为粗品氯化亚砜提馏的热源,保证精馏塔提馏段具有足够的热量；再沸器中的一氯化硫以泵送强制循环,降低一氯化硫加热温度而增加循环流量,使之主要以液态形式携带精馏塔内汽体所必需的热量。降低了一氯化硫的循环温度,降低对设备、材质的设计要求,大大减少精馏塔中上升的一氯化硫蒸汽,减少了氯化亚砜成品的回流循环需要量,降低还原用片状硫磺用量,减少堵塞精馏塔的可能性,提高氯化亚砜成品质量；釆用立式液下泵作为循环泵,杜绝了工艺介质的泄漏。(The invention relates to a thionyl chloride rectification method. According to the invention, sulfur monochloride which flows down to the bottom of the rectifying tower enters a reboiler for heating forced circulation at a large flow rate through a vertical submerged circulating pump, a gas-liquid (liquid phase is taken as a main component) mixture subjected to heat exchange and temperature rise rises and enters a stripping section at the lower part of the rectifying tower as a heat source for stripping crude thionyl chloride, so that the sufficient heat is ensured to be provided for the stripping section of the rectifying tower; the sulfur monochloride in the reboiler is forcibly circulated by a pump, the heating temperature of the sulfur monochloride is reduced, and the circulating flow is increased, so that the sulfur monochloride mainly carries the heat required by the gas in the rectifying tower in a liquid form. The circulating temperature of the sulfur monochloride is reduced, the design requirements on equipment and materials are reduced, the sulfur monochloride steam rising in the rectifying tower is greatly reduced, the reflux circulating requirement of the finished product of the thionyl chloride is reduced, the using amount of the flaky sulfur for reduction is reduced, the possibility of blocking the rectifying tower is reduced, and the quality of the finished product of the thionyl chloride is improved; a vertical submerged pump is used as a circulating pump, so that leakage of process media is avoided.)

1. A thionyl chloride rectification method is characterized by comprising the following steps: pumping the crude thionyl chloride into the middle part of a rectifying tower through a feed pump, and directly exchanging heat with the rising thionyl chloride, sulfur dichloride, sulfur monochloride steam and the downward-flowing sulfur monochloride in the rectifying tower from the downward direction to a stripping section; changing thionyl chloride and sulfur dichloride into steam, rising the steam to a rectifying section, carrying out countercurrent mass transfer purification on the steam and the finished product thionyl chloride which is condensed by a condenser and then flows back to the upper part of a tower, wherein the sulfur dichloride is reduced into the sulfur monochloride from the sulfur monochloride in a sulfur reduction tower or is partially removed, then entering the lower part of the sulfur reduction tower from the tower top through a pipeline, reducing the gas sulfur dichloride in the tower into liquid sulfur monochloride by flaky sulfur, and automatically flowing to the upper part of the rectifying tower from the bottom of the sulfur reduction tower; the thionyl chloride gas after reduction and purification enters the hot side of a condenser from the top of a sulfur reduction tower through a pipeline, and after the thionyl chloride gas is condensed by indirect heat exchange with cooling water on the cold side, part of the gas flows automatically and returns to a rectifying section at the upper part of a rectifying tower for mass transfer purification, and part of the gas flows automatically and enters a thionyl chloride recovery device; the sulfur monochloride comprises sulfur monochloride heated by a reboiler, and thionyl chloride and sulfur dichloride in a crude product material are evaporated and vaporized to ascend by taking a liquid phase as a heat source in the process of flowing under a stripping section; the sulfur monochloride flows to the bottom of the rectifying tower and flows to a receiving tank automatically, then enters a reboiler for heating and forced circulation at a large flow rate through a submerged circulating pump, a liquid phase after heat exchange and temperature rise is a main gas-liquid mixture, rises and enters a stripping section at the lower part of the rectifying tower to serve as a heat source for crude product stripping, and the sufficient heat is ensured in the stripping section of the rectifying tower; and pumping redundant sulfur monochloride to a sulfur monochloride recovery device by a submerged circulation pump to be used as a front-stage raw material for synthesizing thionyl chloride.

2. The thionyl chloride rectification method as claimed in claim 1, characterized in that: the submerged circulating pump is a vertical submerged pump.

3. The thionyl chloride rectification method as claimed in claim 1, characterized in that: the thionyl chloride recovery device is a thionyl chloride storage tank.

4. The thionyl chloride rectification method as claimed in claim 1, characterized in that: and the sulfur monochloride which flows downwards to the bottom of the rectifying tower completely enters a receiving tank, and then enters a reboiler at a large flow rate through a sulfur monochloride liquid lower circulating pump for heating and forced circulation.

5. The thionyl chloride rectification method as claimed in claim 1, characterized in that: the sulfur monochloride recovery device is a sulfur monochloride storage tank.

6. The thionyl chloride rectification method as claimed in claim 1, characterized in that: the following devices were used:

the device comprises a feed pump, a rectifying tower, a sulfur reduction tower, a condenser, a reboiler and a submerged circulating pump; the inlet of the feed pump is a crude product inlet, and the outlet of the feed pump is connected with the inlet of the middle part of the rectifying tower; a steam outlet of the rectifying tower is connected with a steam inlet of the sulfur reduction tower, a thionyl chloride gas outlet of the sulfur reduction tower is connected with a hot side inlet of the condenser, and a sulfur monochloride liquid outlet of the sulfur reduction tower is connected with a rectifying section inlet of the rectifying tower; the outlet at the hot side of the condenser is respectively connected with a thionyl chloride recovery device and the inlet of the other rectifying section of the rectifying tower; the bottom of the rectifying tower is provided with a sulfur monochloride liquid outlet receiving groove inlet, an inlet of the submerged circulating pump is immersed below the liquid level of the sulfur monochloride in the receiving groove, an outlet of the submerged circulating pump is respectively connected with a reboiler cold side inlet and a sulfur monochloride recovery device, and an outlet of the reboiler cold side is connected with a stripping section inlet of the rectifying tower.

7. The thionyl chloride rectification method as set forth in claim 6, characterized in that: the inlet of the feeding pump is provided with a crude product source pipe.

8. The thionyl chloride rectification method as set forth in claim 6, characterized in that: the condenser condenses by circulating cooling water.

9. The thionyl chloride rectification method as set forth in claim 6, characterized in that: the sulfur monochloride liquid at the bottom of the rectifying tower flows to the receiving tank through an outlet, and the submerged circulating pump is arranged above the receiving tank.

Technical Field

The invention belongs to the technical field of chemical industry, and relates to a thionyl chloride rectification method.

Background

Thionyl chloride is called yaSulfuryl chloride with a molecular formula of SOCL₂The product produced by the synthesis device is a crude product and contains thionyl chloride (boiling point of 78.8 ℃), sulfur monochloride (also called disulfide dichloride, boiling point of 138 ℃) and sulfur dichloride (boiling point of 59.6 ℃), and qualified products can be obtained only by rectification.

As shown in fig. 1, the conventional thionyl chloride rectification apparatus is composed of a feed pump, a rectification column, a condenser, a sulfur reduction column, a thionyl chloride storage tank, a receiving tank (which can be replaced by a bottom section of the rectification column), a reboiler, a sulfurous chloride pump, a sulfurous chloride storage tank, and the like.

Pumping the crude thionyl chloride into the middle part of a rectifying tower through a feed pump, and directly exchanging heat with rising thionyl chloride, sulfur dichloride, sulfur monochloride steam and downward-flowing sulfur monochloride in the tower from a downward moving part to a stripping section. The thionyl chloride and the sulfur dichloride are changed into steam and then rise to a rectifying section, the steam and a finished product which is condensed by a condenser and then flows back to the upper part of a tower are subjected to countercurrent mass transfer purification, wherein the sulfur dichloride is partially removed by being reduced into the sulfur monochloride by the sulfur monochloride dissolved or carried in the sulfur monochloride from a sulfur reduction tower, then the sulfur monochloride enters the lower part of the sulfur reduction tower from the tower top through a pipeline, the gas sulfur dichloride in the tower is reduced into the liquid sulfur monochloride by the sheet sulfur, and the liquid sulfur monochloride automatically flows to the upper part of the rectifying tower from the bottom of the sulfur reduction. The thionyl chloride gas after reduction and purification enters the hot side of a condenser through a pipeline from the top of a sulfur reduction tower, indirectly exchanges heat with circulating cooling water, part of the condensed gas automatically flows back to enter a rectifying section at the upper part of a rectifying tower for mass transfer purification, and part of the condensed gas automatically flows into a thionyl chloride storage tank. The sulfur monochloride (including sulfur monochloride heated by a reboiler) is used as a heat source in the process that a liquid phase flows under a stripping section to evaporate and vaporize the thionyl chloride and the sulfur dichloride in the crude product material to flow upwards. And (3) allowing part of downward trickling sulfur chloride to enter the cold side of the reboiler through a pipeline by means of gravity difference, and allowing a gas-liquid mixture subjected to indirect heat exchange with water vapor at the hot side and temperature rise to ascend and enter a stripping section at the lower part of the rectifying tower to serve as a heat source for crude product stripping. And the redundant sulfur monochloride automatically flows into a receiving tank and is pumped to a sulfur monochloride storage tank by a sulfur monochloride pump to be used as a front-stage raw material for synthesizing thionyl chloride.

The existing rectification process needs a reboiler to heat the sulfur monochloride to boiling, and a vapor-liquid mixture of the sulfur monochloride rises to enter a stripping section at the lower part of a rectification tower to be used as a heat source for stripping crude thionyl chloride. Because of the influence of temperature, the density of the sulfur monochloride at the bottom of the rectifying tower is larger than that of the sulfur monochloride in the reboiler, and when the sulfur monochloride in the reboiler is heated and rises, the sulfur monochloride at the bottom of the rectifying tower can be supplemented by self-flowing, so that natural circulation is formed.

As the heat required by stripping thionyl chloride is carried by high-boiling-point sulfur monochloride vapor, the reboiling temperature of the existing rectification process is required to be higher, so that the circulating amount of thionyl chloride at a rectification section is increased, and the energy consumption is increased. Meanwhile, excessive non-thionyl chloride gas in the rectification section rises to the top of the tower, and the color of the finished product is adversely affected. In addition, excessive sulfur monochloride gas enters a sulfur reduction tank at the uppermost part of the device, so that the consumption of molten sulfur is increased, and the distillation tower is easy to block.

The invention changes the natural circulation of the sulfur monochloride in the reboiler into the pump forced circulation, reduces the heating temperature of the sulfur monochloride and increases the circulation flow, so that the sulfur monochloride carries the heat required by stripping the thionyl chloride and the sulfur dichloride in the rectifying tower. The circulating temperature of the sulfur monochloride is reduced, so that the design requirements on equipment and materials are reduced, and sulfur monochloride steam rising in the rectifying tower is greatly reduced (even theoretically not), so that the reflux circulation quantity of the finished product of the thionyl chloride is reduced, the consumption of the flaky sulfur for reduction is reduced, the possibility of blocking the rectifying tower is reduced, and the improvement of the quality of the finished product of the thionyl chloride is facilitated. The sulfur monochloride circulating pump is a vertical submerged pump arranged above the receiving tank, and a shaft seal of the sulfur monochloride circulating pump is positioned at the upper part of the pump outside the receiving tank and is positioned in normal-temperature air, so that leakage of a liquid process medium of the pump is avoided; the inlet of the device is immersed below the liquid level of the sulfur monochloride in the receiving tank, and the friction pair of the device is self-lubricated by a liquid medium; because the circulating temperature of the sulfur monochloride is reduced and the sulfur monochloride is far away from the boiling point, the requirements on gas phase sealing are reduced, the requirements on the material and the manufacture of the pump are reduced, the manufacturing cost is reduced, the service life of equipment is prolonged, and the operation cost is reduced.

Disclosure of Invention

The invention aims to provide a thionyl chloride rectification method.

The invention specifically comprises the following steps: pumping the crude thionyl chloride into the middle part of a rectifying tower through a feed pump, and directly exchanging heat with rising thionyl chloride, sulfur dichloride, sulfur monochloride steam and downward-flowing sulfur monochloride in the tower from a downward moving part to a stripping section. (ii) a The thionyl chloride and sulfur dichloride are changed into steam and then rise to a rectifying section, the steam and the finished product thionyl chloride which is condensed by a condenser and then flows back to the upper part of a tower are subjected to countercurrent mass transfer purification, wherein the sulfur dichloride is partially removed by being reduced into the sulfur monochloride by sulfur dissolved or carried in the sulfur monochloride from a sulfur reduction tower, then the sulfur monochloride enters the lower part of the sulfur reduction tower from the tower top through a pipeline, the gas sulfur dichloride in the tower is reduced into liquid sulfur monochloride by sheet sulfur, and the liquid sulfur monochloride flows to the upper part of the rectifying tower from the bottom of the sulfur reduction tower. The thionyl chloride gas after reduction and purification enters the hot side of a condenser through a pipeline from the top of a sulfur reduction tower, and after the thionyl chloride gas is condensed by indirect heat exchange with cooling water on the cold side, a part of the thionyl chloride gas automatically flows back to enter a rectifying section at the upper part of a rectifying tower for mass transfer and purification, and a part of the thionyl chloride gas automatically flows into a thionyl chloride recovery device. The sulfur monochloride (including sulfur monochloride heated by a reboiler) is used as a heat source in the process of flowing liquid phase under a stripping section to vaporize and evaporate the thionyl chloride and the sulfur dichloride in the crude product material to flow upwards. The sulfur monochloride flowing down to the bottom of the rectifying tower automatically flows to a receiving tank, then enters a reboiler for heating and forced circulation at a large flow rate through a vertical submerged circulating pump arranged on the receiving tank, and a gas-liquid (liquid phase is taken as a main component) mixture after heat exchange and temperature rise rises to enter a stripping section at the lower part of the rectifying tower to serve as a heat source for crude product stripping, so that the stripping section of the rectifying tower is ensured to have enough heat; and pumping redundant sulfur monochloride to a sulfur monochloride recovery device by a submerged circulation pump to be used as a front-stage raw material for synthesizing thionyl chloride.

The submerged circulating pump is a vertical submerged pump.

The thionyl chloride recovery device is a thionyl chloride storage tank.

And the sulfur monochloride which flows downwards to the bottom of the rectifying tower completely enters a receiving tank, and then enters a reboiler at a large flow rate through a sulfur monochloride submerged pump for heating and forced circulation.

The sulfur monochloride recovery device is a sulfur monochloride storage tank.

The invention adopts the following devices:

the device comprises a feeding pump, a rectifying tower, a sulfur reduction tower, a condenser, a reboiler, a submerged circulating pump and the like. The inlet of the feed pump is a crude product inlet, and the outlet of the feed pump is connected with the inlet of the middle part of the rectifying tower; a steam outlet of the rectifying tower is connected with a steam inlet of the sulfur reduction tower, a thionyl chloride steam outlet of the sulfur reduction tower is connected with a hot side inlet of the condenser, and a liquid outlet of the sulfur reduction tower is connected with a rectifying section inlet of the rectifying tower; the hot side outlet of the condenser is respectively connected with a thionyl chloride recovery device and a circulating thionyl chloride inlet of the rectifying tower; and a sulfur chloride outlet at the bottom of the rectifying tower is connected with an inlet of the receiving tank, an inlet of the submerged circulating pump is immersed below the liquid level in the receiving tank, an outlet of the submerged circulating pump is respectively connected with a cold side inlet of the reboiler and a sulfur chloride recovery device, and an outlet of the cold side of the reboiler is connected with an inlet of a stripping section of the rectifying tower.

The inlet of the feeding pump is provided with a crude product source pipe.

The condenser indirectly exchanges heat and condenses through circulating cooling water.

And the sulfur monochloride liquid at the bottom of the rectifying tower automatically flows into the receiving tank.

The submerged circulating pump is arranged above the receiving tank, and the lower part of the submerged circulating pump is immersed below the liquid level of the sulfur monochloride.

On the premise of ensuring the heat required by the stripping of the rectifying tower, the invention improves the circulating flow of the sulfur monochloride, reduces the heating temperature of the reboiler, and ensures that the sulfur monochloride (brownish red) basically keeps liquid phase operation in the whole rectifying process, thereby reducing the reflux consumption of the finished product of the sulfoxide chloride and being beneficial to improving the quality of the finished product of the sulfoxide chloride compared with the traditional process. The heating temperature of the reboiler is reduced, so that the requirement on the heating steam grade of the reboiler is reduced. The heating temperature of the reboiler is reduced, so the requirements of equipment materials and structures are reduced, and the safety of equipment operation is improved. Compared with the traditional process that the sulfur monochloride is in a vapor-liquid mixed state after being heated by a reboiler, the sulfur monochloride mainly runs in a liquid state in a circulating mode and is more stable. Because the circulating flow of the sulfur monochloride is improved, the dry tower phenomenon of the stripping section of the rectifying tower is reduced or the requirement on the number of trays is reduced, and the stripping effect is enhanced. The sulfur monochloride circulating pump is a vertical submerged pump arranged above the receiving tank, and a shaft seal of the sulfur monochloride circulating pump is positioned at the upper part of the pump outside the receiving tank and is positioned in normal-temperature air, so that the leakage of a liquid medium of the pump is avoided; the inlet of the device is immersed below the liquid level of the sulfur monochloride in the receiving tank, and the friction pair of the device is self-lubricated by a liquid medium; because the circulating temperature of the sulfur monochloride is reduced and the sulfur monochloride is far away from the boiling point, the requirements on gas phase sealing are reduced, the requirements on the material and the manufacture of the pump are reduced, the manufacturing cost is reduced, the service life of equipment is prolonged, and the operation cost is reduced.

Drawings

FIG. 1 is a schematic flow diagram of a conventional thionyl chloride rectification apparatus;

FIG. 2 is a schematic flow chart of the present invention.

Detailed Description

As shown in FIG. 2, the inlet of the feed pump is connected with the crude product source pipe, and the outlet of the feed pump is connected with the middle part of the rectifying tower. The rectifying tower is provided with six pipe interfaces which are respectively a pipe interface for connecting a feed pump (connected with an outlet of the feed pump in the middle of the rectifying tower), an inlet pipe interface for connecting a sulfur reduction tower (connected with a steam inlet pipe orifice at the lower part of the sulfur reduction tower at the top of the rectifying tower), an outlet pipe interface for connecting the sulfur reduction tower (connected with a sulfur monochloride liquid outlet pipe orifice at the bottom of the sulfur reduction tower at the upper part of the rectifying tower), an outlet pipe interface for connecting a condenser (connected with a cold side thionyl chloride liquid outlet pipe at the upper part of the rectifying tower), a pipe interface for connecting a reboiler (connected with a cold side outlet pipe of the reboiler at the lower part of the rectifying tower), and a receiving groove pipe interface (connected with a sulfur monochloride liquid inlet pipe at the bottom of the rectifying tower). The sulfur reduction tower is provided with three pipe interfaces which are respectively connected with a pipe interface at the upper part of the rectifying tower (connected with a sulfur monochloride liquid inlet pipe interface at the bottom of the sulfur reduction tower), a pipe interface at the top part of the rectifying tower (connected with a steam gas outlet pipe interface at the top part of the rectifying tower at the lower part of the sulfur reduction tower) and a condenser pipe interface (connected with a hot side inlet pipe of the condenser at the top part of the sulfur reduction tower). The condenser is provided with four interfaces, a hot side inlet pipe of the condenser is connected with a thionyl chloride steam outlet pipe of the sulfur reduction tower, the hot side outlet pipe is respectively connected with an inlet pipe interface of a thionyl chloride storage tank and a thionyl chloride reflux circulating pipe interface at the upper part of the rectifying tower, and the cold side of the condenser is connected with a circulating cooling water inlet pipe and a circulating cooling water outlet pipe. The reboiler is provided with four pipe interfaces, which are respectively the pipe interface of the cold side connected with the stripping section of the rectifying tower (on the upper part of the reboiler, the cold side outlet is connected with the pipe interface of the reboiler connected with the stripping section on the lower part of the rectifying tower), the pipe interface connected with the submerged circulating pump (on the bottom of the reboiler, the cold side inlet is connected with the outlet interface of the submerged circulating pump), the pipe interface connected with the steam pipe (on the upper part of the hot side of the reboiler, the hot side inlet is connected with the source pipe orifice of the hot steam), and the pipe interface connected with the condensed water pipe (on the lower part of the hot side of the reboiler. The inlet of the receiving groove is connected with a sulfur monochloride outlet at the bottom of the rectifying tower. The inlet of the submerged circulating pump is immersed below the liquid level of the sulfur monochloride in the receiving tank, and the outlet is respectively connected with the reboiler and the sulfur monochloride storage tank.

Pumping the crude thionyl chloride into the middle part of a rectifying tower through a feed pump, and directly exchanging heat with rising thionyl chloride, sulfur dichloride, sulfur monochloride steam and downward-flowing sulfur monochloride in the tower from a downward moving part to a stripping section. The thionyl chloride and sulfur dichloride are changed into steam and then rise to a rectifying section, the steam and the finished product thionyl chloride which is condensed by a condenser and then flows back to the upper part of a tower are subjected to countercurrent mass transfer purification, wherein the sulfur dichloride is partially removed by being reduced into the sulfur monochloride by sulfur dissolved or carried in the sulfur monochloride from a sulfur reduction tower, then the sulfur monochloride enters the lower part of the sulfur reduction tower from the tower top through a pipeline, the gas sulfur dichloride in the tower is reduced into liquid sulfur monochloride by sheet sulfur, and the liquid sulfur monochloride flows to the upper part of the rectifying tower from the bottom of the sulfur reduction tower. The thionyl chloride gas after reduction and purification enters the hot side of a condenser through a pipeline from the top of a sulfur reduction tower, indirectly exchanges heat with circulating cooling water on the cold side, part of the condensed gas automatically flows back to enter a rectifying section at the upper part of a rectifying tower for mass transfer and purification, and part of the condensed gas automatically flows into a thionyl chloride storage tank. The sulfur monochloride (including sulfur monochloride heated by a reboiler) is used as a heat source in the process of flowing liquid phase under a stripping section to vaporize and evaporate the thionyl chloride and the sulfur dichloride in the crude product material to flow upwards. And the sulfur monochloride flowing down to the bottom of the rectifying tower completely enters the receiving tank, and then enters a reboiler for heating forced circulation at a large flow rate through a sulfur monochloride submerged pump arranged on the receiving tank, and a gas-liquid (liquid phase is taken as a main component) mixture subjected to heat exchange and temperature rise ascends to enter a stripping section at the lower part of the rectifying tower to serve as a heat source for crude product stripping, so that the sufficient heat of the stripping section of the rectifying tower is ensured. And (3) pumping redundant part of sulfur chloride to a sulfur chloride storage tank by a submerged circulation pump to be used as a front-stage raw material for synthesizing the sulfoxide chloride.

In order to solve the sealing problem of the sulfur monochloride circulating pump, the sulfur monochloride circulating pump used in the invention is a vertical submerged pump.