阅读说明：本技术 一种co深冷分离装置解冻和冷态开车的方法 (Method for unfreezing and cold-state driving of CO cryogenic separation device ) 是由 梁宝剑 张鸿儒 门俊杰 杜霞 楚永利 侯刘涛 武红旗 沈小炎 蒋都钦 叶宏海 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种CO深冷分离系统装置解冻及冷态开车的方法。具体为在系统工艺气退气后,将高压合成气分离器及中压合成气分离器中的全部液体沿工艺管线排入CO/N<Sub>2</Sub>塔分离塔中,关闭各工艺管线阀门；利用CO/N<Sub>2</Sub>压缩机对CO深冷分离系统提供大流量解冻用氮气按照工艺气流程方向,依次进入冷却器、冷凝器、高压合成气分离器、中压合成气分离器及液态CO容器进行解冻；解冻结束后进行冷态开车,开车完成即可进行接气。该方法解冻时间短,无需将CO/N<Sub>2</Sub>压缩机进行停车,同时通过对系统残液进行保存,避免了系统中液氮的排出,为系统解冻后开车保留大部分冷量,缩短了开车时间；解冻及开车效率高,减少了资源消耗,避免了原料排放对环境造成的污染,具有很好的社会经济效益。(The invention discloses a method for unfreezing and cold-state driving of a CO cryogenic separation system device. Particularly, after the process gas of the system is degassed, all liquid in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator is discharged into CO/N along the process pipeline 2 In the tower separation tower, closing each process pipeline valve; by using CO/N 2 The compressor provides large-flow nitrogen for unfreezing for the CO cryogenic separation system, and the nitrogen sequentially enters the cooler, the condenser, the high-pressure synthesis gas separator, the medium-pressure synthesis gas separator and the liquid CO container to be unfrozen according to the process flow direction; and after thawing, carrying out cold-state driving, and carrying out air receiving after driving is finished. The method has short thawing time, and no need of adding CO/N 2 The compressor is stopped, and meanwhile, residual liquid in the system is stored, so that the discharge of liquid nitrogen in the system is avoided, most of cold energy is reserved for the driving of the system after thawing, and the driving time is shortened; the unfreezing and driving efficiency is high, the resource consumption is reduced, the pollution of raw material discharge to the environment is avoided, and the social and economic benefits are good.)

1. The CO cryogenic separation device is characterized by comprising a synthesis gas cooling and condensing device, a hydrogen separation device and a CO/N (carbon monoxide/nitrogen) device₂A separation device;

the synthesis gas condensing device is used for cooling and condensing the synthesis gas entering the cryogenic separation device;

the hydrogen separation device is communicated with the synthesis gas condensing device and is used for separating hydrogen in the synthesis gas after cooling and condensing;

the CO/N₂The separation device comprises a two-phase feeding tank, a carbon monoxide/nitrogen tower separation tower, a liquid carbon monoxide container and a CO/N separator₂Column reboiler, CO/N₂The system comprises a tower condenser, a two-phase separator, a liquid CO buffer tank and a liquid CO thermosyphon tank;

one end of the hydrogen separation device is communicated with the synthesis gas condensation device, and the other end of the hydrogen separation device is led out of the two branch pipes through a tee joint; one branch pipe passes through a condenser E2 and then is connected with CO/N₂Connected to the tower reboiler, CO/N₂The tower reboiler is connected to a two-phase feed tank, which is connected to the CO/N₂The tower separation towers are communicated; the other branch pipe is communicated with a two-phase feeding tank, and the two-phase feeding tank is communicated with CO/N₂The tower separation towers are communicated; CO/N₂The outlet at the bottom end of the tower separation tower is communicated with a liquid CO container through a pipeline, and the outlet at the top end of the liquid CO container is communicated with CO/N through a pipeline₂The compressors are communicated; the liquid CO container is also communicated with a liquid CO buffer tank, the liquid CO buffer tank is communicated with a liquid CO thermosiphon tank, and the liquid CO thermosiphon tank is communicated with CO/N through a pipeline₂The compressors are communicated.

2. The cryogenic CO separation device of claim 1, wherein the syngas condensing means includes a cooler connected to a syngas intake conduit, a condenser connected to a cooler outlet;

the hydrogen separation device comprises a high-pressure synthesis gas separator and a medium-pressure synthesis gas separator; the high-pressure synthesis gas separator is respectively connected with the condenser and the medium-pressure synthesis gas separator, and the top end of the high-pressure synthesis gas separator is communicated to a downstream process through a gas pipeline; the high-pressure synthesis gas separator is used for separating hydrogen-rich gas, the hydrogen-rich gas is discharged from the top end of the high-pressure synthesis gas separator, and the hydrogen-rich gas is subjected to heat exchange to normal temperature through a condenser and a cooler and then is led to a downstream process; the medium-pressure synthesis separator is respectively communicated with the high-pressure synthesis gas separator and the three-way joint.

3. A method for defrosting and cold starting of a cryogenic CO separation plant according to claim 1 or 2, comprising the steps of:

after the system process gas of the CO cryogenic separation device is discharged, all liquid in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator is discharged into CO/N along a process pipeline₂The liquid level in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator in the tower separation tower is zero; closing each process pipeline valve; at the same time, to CO/N₂The compressor is filled with low-pressure nitrogen to carry out the internal circulation operation of the system, thereby ensuring that the mobile equipment does not stop operation or restarting CO/N under the working condition of nitrogen₂A compressor;

by using CO/N₂The compressor provides large-flow nitrogen for unfreezing for the cryogenic separation system, the nitrogen for unfreezing enters the cooler, the condenser, the high-pressure synthesis gas separator, the medium-pressure synthesis gas separator and the liquid CO container in sequence according to the process flow direction for unfreezing, and then the nitrogen for unfreezing is discharged after heat exchange is carried out through the condenser and the cooler until the unfreezing is finished;

and after thawing, carrying out cold-state driving, and carrying out air receiving after the cold-state driving is finished.

4. The method for unfreezing and cold-state driving of the CO cryogenic separation device according to claim 3, characterized by comprising the following steps:

s1, unfreezing the cryogenic separation system:

after the process gas of the system is degassed, all liquid in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator is discharged into CO/N along the process pipeline₂In the column separation column, up to heightThe liquid levels in the pressure synthesis gas separator and the medium-pressure synthesis gas separator are zero; closing each process pipeline valve; at the same time, to CO/N₂The compressor is filled with low-pressure nitrogen to carry out the internal circulation operation of the system, thereby ensuring that the mobile equipment does not stop operation or restarting CO/N under the working condition of nitrogen₂A compressor;

by using CO/N₂The compressor provides large-flow nitrogen for unfreezing for the cryogenic separation system, the nitrogen for unfreezing enters the cooler, the condenser, the high-pressure synthesis gas separator, the medium-pressure synthesis gas separator and the liquid CO container in sequence according to the process flow direction, and then the nitrogen for unfreezing is discharged after heat exchange is carried out through the condenser and the cooler until the unfreezing is finished;

s2, cold-state start of the cryogenic separation system:

when external liquid nitrogen is introduced to provide cold energy for the system, the system directly introduces synthesis gas from the front end, and the synthesis gas after passing through the cooling condensing device is used for stamping the high-pressure synthesis gas separator and establishing liquid level; then sequentially synthesizing gas separator and CO/N by medium pressure₂The tower separation tower, the liquid CO buffer tank and the liquid CO thermosiphon tank are punched and the liquid level is established; when the liquid level is established, the vehicle is normally driven.

5. The unfreezing and cold-state starting method of the CO cryogenic separation device according to claim 3 or 4, wherein the unfreezing speed during unfreezing is controlled to be 3-5 ℃/h;

when the temperature of the unfreezing nitrogen entering pipeline at the inlet of the condenser is-5 ℃, the outlet temperature of the high-pressure synthesis gas separator reaches-40 ℃, and CO/N is added₂Compressor inlet CO₂Content is less than 0.3PPm, CH₃When OH is less than 0.1PPm, thawing is finished.

6. The defrosting and cold-state starting method for the CO cryogenic separation device according to claim 3 or 4, characterized in that the charging pressure of the high-pressure synthesis gas separator is controlled to be 3.0MPa, the charging pressure of the medium-pressure synthesis gas separator is controlled to be 0.67MPa, and CO/N is controlled₂The pressure of the column separator is controlled to be 0.32 MPa.

7. The method for unfreezing and cold-state starting of the CO cryogenic separation device according to claim 3 or 4, characterized in that the method comprises a high-pressure synthesis gas separator, a medium-pressure synthesis gas separator, and CO/N₂When the liquid levels of the tower separation tower, the liquid CO buffer tank and the liquid CO thermosiphon tank are established to be 40-50%, the start-up is finished.

8. The method for defrosting and cold starting of a CO cryogenic separation device according to claim 7, wherein the liquid level rising speed is controlled to be 0.5%/min.

9. The method for defrosting and cold starting of the CO cryogenic separation device according to claim 7, wherein the top outlet temperature of the high-pressure synthesis gas separator is-184 ℃ at the end of the starting.

Technical Field

The invention belongs to the technical field of cryogenic separation, namely cryogenic rectification. In particular to a CO cryogenic separation system, a pipeline unfreezing method of the CO cryogenic separation system and a driving method of the system in a cold state.

Background

Cryogenic separation (also called cryogenic rectification) is a process in which gas is compressed and cooled mechanically and then rectified by the difference in boiling point of the gas to separate different gases. In the process of rectifying the gas, the method firstly needs to provide a large amount of cold energy from the outside to liquefy the gas, and then separates each medium again through heat exchange.

In the operation process of the device, when gas enters equipment, the gas with high boiling point is easy to solidify under the low temperature condition (-about 145 ℃), so that the equipment is blocked; equipment leakage, particularly heat exchanger leakage, also often occurs in the operation process, and due to the low-temperature characteristic of the device (the temperature reaches about minus 145 ℃), the leaked pipelines are easy to freeze in the pipelines to cause equipment blockage. Therefore, in the cryogenic separation process, the defrosting of the equipment is an indispensable operation step in the system, and the defrosting of the equipment is also a very important maintenance means in the operation process of the cryogenic separation system.

Disclosure of Invention

The invention aims at the technical problems that: after de-aeration of prior art systems, CO/N₂The compressor needs to be shut down; the unfreezing time is long (as long as 72 hours) after the transportation is stopped, and the low-pressure nitrogen quantity required by unfreezing is large; starting the unfrozen system, and supplementing a large amount of liquid nitrogen to the system before introducing the process gas to cool the system and build a liquid level; the whole process from unfreezing to driving is large in emptying amount, and material waste is serious.

In order to solve the problems, the invention provides a method for unfreezing and cold-state driving of a CO cryogenic separation device. The method has short thawing time, and no need of adding CO/N₂The compressor is stopped, and meanwhile, residual liquid in the system is stored, so that the discharge of liquid nitrogen in the system is avoided, and most of cold energy is reserved for driving the system after the system is unfrozen; the method reduces the defrosting time, improves the defrosting and driving efficiency, obviously reduces the resource consumption, avoids the pollution of the raw material discharge to the environment, and has good social and economic benefits. Even when the compressor is stopped due to the fact that the system needs to be overhauled, the compressor can be unfrozen again by introducing unfreezing gas, large-flow unfreezing gas is provided for the system, and the system can still be unfrozen in the forward direction.

The invention is realized by the following technical scheme

The CO cryogenic separation device comprises a synthesis gas cooling and condensing device, a hydrogen separation device and a CO/N (carbon monoxide/nitrogen) device₂A separation device;

the synthesis gas condensing device is used for cooling and condensing the synthesis gas entering the cryogenic separation system;

the hydrogen separation device is communicated with the synthesis gas condensing device and is used for separating hydrogen in the synthesis gas after cooling and condensing;

the CO/N₂The separation device comprises a two-phase feed tank, CO/N₂Column separation column, liquid CO vessel, CO/N₂Column reboiler, CO/N₂The system comprises a tower condenser, a two-phase separator, a liquid CO buffer tank and a liquid CO thermosyphon tank; (CO/N)₂The separation device is mainly used for low-temperature liquid rectification to extract CO with high purity (the CO content is 98.5 percent, and other components are 1.5 percent), and the CO with high purity passes through a CO/N after heat exchange to normal temperature by a condenser and a cooler and then passes through a CO/N₂The compressor is sent to the outdoor downstream process);

one end of the hydrogen separation device is communicated with the synthesis gas condensation device, and the other end of the hydrogen separation device is led out of the two branch pipes through a tee joint; one branch pipe passes through a condenser E2 and then is connected with CO/N₂Connected to the tower reboiler, CO/N₂The tower reboiler is connected to a two-phase feed tank, which is connected to the CO/N₂The tower separation towers are communicated; the other branch pipe is communicated with a two-phase feeding tank, and the two-phase feeding tank is communicated with CO/N₂The tower separation towers are communicated; CO/N₂The outlet at the bottom end of the tower separation tower is communicated with a liquid CO container through a pipeline, and the outlet at the top end of the liquid CO container is communicated with CO/N through a pipeline₂The compressor is communicated, the liquid CO container is also communicated with a liquid CO buffer tank, the liquid CO buffer tank is communicated with a liquid CO thermosiphon tank, and the liquid CO thermosiphon tank is communicated with CO/N through a pipeline₂The compressors are communicated.

The synthesis gas condensing device comprises a cooler connected with a synthesis gas inlet pipeline and a condenser connected with an outlet of the cooler; (the cooler and the condenser are frequently icing devices);

the hydrogen separation device comprises a high-pressure synthesis gas separator and a medium-pressure synthesis gas separator; the high-pressure synthesis gas separator is respectively connected with the condenser and the medium-pressure synthesis gas separator, and the top end of the high-pressure synthesis gas separator is communicated to a downstream process through a gas pipeline; wherein, the high-pressure synthesis gas separator is mainly used for flash separationHydrogen-rich gas, hydrogen-rich gas (H)₂The content of 86.56 percent, the CO content of 12.74 percent and the other components of 0.69 percent) are discharged from the top end of the high-pressure synthesis gas separator, and then the mixture is subjected to heat exchange by a condenser and a cooler to the normal temperature and then is led to the downstream working procedure; the liquid which is not completely flashed enters a medium-pressure synthesis separator through a bottom pipeline of the high-pressure synthesis separator. The medium-pressure synthesis separator is respectively communicated with the high-pressure synthesis gas separator and the synthesis gas condensing device, and is mainly used for secondary flash evaporation separation of hydrogen; the gas separated by flash evaporation is communicated with a synthesis gas condensing device, and is sent to a downstream process after being subjected to heat exchange to normal temperature through a condenser and a cooler in sequence; liquid into CO/N₂And (4) a separation device.

The unfreezing and cold-state driving method for the CO cryogenic separation device comprises the following steps of:

after the system process gas of the CO cryogenic separation device is discharged, all liquid in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator is discharged into CO/N along a process pipeline₂The liquid level in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator in the tower separation tower is zero; closing each process pipeline valve; at the same time, to CO/N₂The compressor is filled with low-pressure nitrogen to carry out the internal circulation operation of the system, thereby ensuring that the mobile equipment does not stop operation or restarting CO/N under the working condition of nitrogen₂A compressor;

by using CO/N₂The compressor provides large flow (the large flow is 20000 Nm)³About/h, and the flow rate in the reverse thawing of the prior art is 6000Nm³About/h) unfreezing nitrogen, sequentially entering a cooler, a condenser, a high-pressure synthesis gas separator, a medium-pressure synthesis gas separator and a liquid CO container for unfreezing according to the process flow direction of the unfreezing nitrogen, then performing heat exchange through the condenser and the cooler, and then emptying until the unfreezing is finished;

and after thawing, carrying out cold-state driving, and carrying out air receiving after the cold-state driving is finished.

The defrosting and cold-state starting method of the CO cryogenic separation device comprises the following steps:

s1, unfreezing the cryogenic separation system:

after the system process gas of the CO cryogenic separation device is discharged, all liquid in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator is discharged into CO/N along a process pipeline₂In the tower separation tower, until the liquid levels in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator are zero; closing each process pipeline valve; at the same time, to CO/N₂The compressor is filled with low-pressure nitrogen to carry out the internal circulation operation of the system, thereby ensuring that the mobile equipment does not stop operation or restarting CO/N under the working condition of nitrogen₂A compressor;

by using CO/N₂The compressor provides large flow (the large flow is 20000 Nm)³About/h, and the flow rate in the reverse thawing of the prior art is 6000Nm³About/h) unfreezing nitrogen, sequentially entering a cooler, a condenser, a high-pressure synthesis gas separator, a medium-pressure synthesis gas separator and a liquid CO container according to the process flow direction of the unfreezing nitrogen, and then emptying after heat exchange through the condenser and the cooler until the unfreezing is finished;

s2, cold-state start of the cryogenic separation system:

when external liquid nitrogen is introduced to provide cold energy for the system, the system directly introduces synthesis gas from the front end, and the synthesis gas after passing through the cooling condensing device is used for stamping the high-pressure synthesis gas separator and establishing liquid level; then sequentially synthesizing gas separator and CO/N by medium pressure₂The tower separation tower, the liquid CO buffer tank and the liquid CO thermosiphon tank are punched and the liquid level is established; when the liquid level is built, the driving is normal.

The method for unfreezing and cold-state starting of the CO cryogenic separation device is characterized in that the unfreezing speed during unfreezing is controlled to be 3-5 ℃/h; through detection, when the temperature of the unfreezing nitrogen entering pipeline at the inlet of the condenser is-5 ℃, the outlet temperature of the high-pressure synthetic gas separator reaches-40 ℃, and CO/N is₂Compressor inlet CO₂Content is less than 0.3PPm, CH₃When OH is less than 0.1PPm, thawing is finished.

The method for unfreezing and cold-state driving of the CO cryogenic separation device has the advantages that the charging pressure of the high-pressure synthesis gas separator is controlled to be 3.0MThe charging pressure of the Pa and medium-pressure synthesis gas separator is controlled to be 0.67MPa, and CO/N₂The pressure of the column separator is controlled to be 0.32 MPa.

The method for unfreezing and cold-state driving of the CO cryogenic separation device comprises a high-pressure synthesis gas separator, a medium-pressure synthesis gas separator and a CO/N₂When the liquid levels of the tower separation tower, the liquid CO buffer tank and the liquid CO thermosiphon tank are established to be 40-50%, the start-up is finished.

According to the method for unfreezing and cold-state starting of the CO cryogenic separation device, the liquid level rising speed is controlled to be 0.5%/min.

According to the unfreezing and cold-state start-up method of the CO cryogenic separation device, when the start-up is finished, the temperature of the top end outlet of the high-pressure synthesis gas separator is-184 ℃.

Compared with the prior art, the invention has the following positive beneficial effects

Drawings

FIG. 1 shows a schematic diagram of a cryogenic CO separation plant.

The symbols in the drawings indicate that: 1 denotes a cooler, 2 denotes a condenser, 3 denotes a high-pressure synthesis gas separator, 4 denotes a medium-pressure synthesis gas separator, and 5 denotes CO/N₂Column separator, 6 denotes a liquid CO vessel, 7 denotes CO/N₂Column reboiler, 8 for two-phase separator, 9 for two-phase feed tank, 10 for CO/N₃Column condenser, 11 for liquid CO surge tank, 12 for liquid CO thermosyphon tank, 13 for medium pressure CO condenser, 14 for three-way connection, 15 for CO product gas line, 16 for nitrogen line on start.

Detailed Description

The present invention will be described in more detail with reference to the following embodiments, which are provided for understanding the technical solutions of the present invention, but are not intended to limit the scope of the present invention.

One embodiment of the present invention provides a cryogenic CO separation device, as shown in FIG. 1, comprising a syngas temperature reduction and condensation device, a hydrogen separation device and a CO/N separation device₂A separation device;

the synthesis gas condensing device is used for cooling and condensing the synthesis gas entering the cryogenic separation system; the synthesis gas condensing device comprises a cooler connected with a synthesis gas inlet pipeline and a condenser connected with the outlet of the cooler;

the hydrogen separation device is communicated with the synthesis gas condensing device and is used for separating hydrogen in the synthesis gas after cooling and condensing; the hydrogen separation device comprises a high-pressure synthesis gas separator and a medium-pressure synthesis gas separator; the high-pressure synthesis gas separator is respectively connected with the condenser and the medium-pressure synthesis gas separator, and the top end of the high-pressure synthesis gas separator is communicated to a downstream process through a gas pipeline (the gas pipeline exchanges heat through the condenser and the cooler); the medium-pressure synthesis separator is respectively communicated with the high-pressure synthesis gas separator and the three-way joint, and the top end of the medium-pressure synthesis gas separator is communicated with other devices through a gas pipeline (the gas pipeline performs heat exchange through a condenser and a cooler);

the CO/N₂The separation device comprises a two-phase feed tank, CO/N₂Column separation column, liquid CO vessel, CO/N₂Column reboiler, CO/N₂The system comprises a tower condenser, a two-phase separator, a liquid CO buffer tank and a liquid CO thermosyphon tank;

one end of the hydrogen separation device is communicated with the synthesis gas condensation device, and the other end of the hydrogen separation device is led out of the two branch pipes through a tee joint; one branch pipe passes through a condenser E2 and then is connected with CO/N₂Connected to the tower reboiler, CO/N₂The tower reboiler is connected to a two-phase feed tank, which is connected to the CO/N₂The tower separation towers are communicated; the other branch pipe is communicated with a two-phase feeding tank, and the two-phase feeding tank is communicated with CO/N₂The tower separation towers are communicated; CO/N₂The outlet at the bottom end of the tower separation tower is communicated with a liquid CO container through a pipeline, and the outlet at the top end of the liquid CO container is communicated with CO/N through a pipeline (the pipeline performs heat exchange through a condenser and a cooler)₂The compressors are communicated; the liquid CO container is also communicated with a liquid CO buffer tank through a pipeline, the liquid CO buffer tank is also communicated with a liquid CO thermosiphon tank through a pipeline, and the liquid CO thermosiphon tank is communicated with CO/N through a pipeline (the pipeline performs heat exchange through a condenser and a cooler)₂The compressors are communicated. Each pipeline is provided with a valve, as shown in figure 1.

The embodiment of the invention also provides a method for unfreezing and cold-state driving the CO cryogenic separation device, and the embodiment unfreezes local icing of the system. Thus, in this system, clogging is accomplished by the "ice" phenomenon that is most likely to occur at the cooler and condenser. When the unfreezing and driving method is adopted, the system does not need to be stopped.

Specifically, as shown in fig. 1, the method for defrosting and cold-state driving of the CO cryogenic separation system includes the following steps: s1, unfreezing the CO cryogenic separation device:

(1) pouring liquid: after the system is discharged with the process gas, the compressor is used for compressing CO/N₂Continuously running, discharging all the liquid remained in the high-pressure synthesis gas separator and the medium-pressure synthesis gas separator into CO/N along the process pipeline₂Storing in a tower separation tower, wherein the liquid levels in the high-pressure synthetic gas separator and the medium-pressure synthetic gas separator are zero, and ending liquid pouring; closing each process pipeline valve;

(2) and (3) unfreezing the system: opening N₂The start process valves F1 and F2 allow circulating nitrogen to enter a cooler, a condenser, a high-pressure synthetic gas separator and a medium-pressure synthetic gas separator in sequence through pipelines for unfreezing, and the circulating nitrogen is discharged through a pipeline at the top of the high-pressure synthetic gas separator and/or the medium-pressure synthetic gas separator through a valve PV107B and/or a PV312B for continuous operation;

when the temperature of nitrogen entering the pipeline at the inlet of the condenser is-5 ℃, and the temperature of the outlet of the high-pressure synthesis gas separator reaches-40 ℃, the thawing is finished; (after unfreezing, start the car in cold state);

wherein the thawing speed of the nitrogen for thawing through the pipeline is controlled to be 3-5 ℃/h;

because the thawing process of the system is that the nitrogen for thawing is carried out along the process flow direction, no influence is caused on residual materials in the system. Therefore, when the process is defrosted, the residual materials in the system are not completely discharged, but are stored in CO/N₂In a column separation column, inOnly the consumption of raw materials is reduced, and the consumption of the discharge time of the raw materials is reduced; and the raw materials are stored in the system, and part of cold energy is reserved for the system, so that after the system is unfrozen, the temperature of the system is not greatly increased under the condition that residual materials exist, the requirement of the cryogenic separation system on the temperature can be met only by providing a small amount of cold energy (liquid nitrogen gas) for the system from the outside, the time consumption of secondary cooling of the system and the consumption of the cold energy are greatly reduced, and the economic benefit is obvious.

S2, cold-state start-up of the CO cryogenic separation device:

(3) after thawing, the front-end purifier has been supplied with gas (the quality of the syngas at the outlet of the front-end purifier must be CO)₂The content is less than 0.1 ppm; CH (CH)₃OH content less than 0.1ppm and then initially entering the cryogenic separation system). Slowly opening a valve HV10B, pressurizing the high-pressure synthesis gas separator after the synthesis gas passes through a cooler and a condenser, controlling the pressurizing speed of the high-pressure synthesis gas separator to be less than or equal to 0.1MPa/min, establishing the liquid level of the high-pressure synthesis gas separator, slowly opening the valve HV10A when the pressure of the high-pressure synthesis gas separator reaches 1.0-1.3 MPa, setting the pressure set value of a valve PV107B to be 3.0MPa, and putting into an automatic control mode until the pressure of the high-pressure synthesis gas separator is stably increased to be 3.0 MPa;

and simultaneously opening a liquid nitrogen boundary area valve TDV306, gradually opening the valve FV307 to 100 percent, and continuously supplementing cold for the system until the requirement is met.

(4) Opening a valve LV10, performing pressurization and liquid level establishment on the medium-pressure synthetic gas separator, simultaneously controlling the pressurization speed of the medium-pressure synthetic gas separator to be less than or equal to 0.1MPa/min by utilizing the opening degree adjustment of a valve PV312B, setting the pressure set value of PV312B to be 0.67MPa when the pressure in the medium-pressure synthetic gas separator reaches 0.3MPa, and putting into an automatic control mode until the pressure of the medium-pressure synthetic gas separator is stably increased to be 0.67 MPa.

(5) Sequentially opening valves LV20, LV23 and LV14 to enable the CO/N obtained in the step (1)₂Pouring the liquid stored in the tower separation tower into a liquid CO container, a liquid CO buffer tank and a liquid CO thermosyphon tank in sequence;when 50% of liquid level in the liquid CO thermosyphon tank is displayed, maintaining the liquid level of the liquid CO thermosyphon tank, and simultaneously keeping the maximum descending speed of the inlet temperature of the high-pressure synthesis gas separator at 15 ℃/h;

and (3) maintaining the opening degrees of a valve LV20 and a valve LV14 unchanged until the liquid levels of the high-pressure synthetic gas separator and the medium-pressure synthetic gas separator reach more than 40%, gradually increasing the pressure of a valve PV107B and the pressure of a valve PV312B at a lifting speed of 0.2MPa/min until the pressure of the valve PV107B reaches 2/3 of the normal production pressure, and increasing the pressure of a valve PV312B to the normal production pressure.

At this time, the valve LV10 and the valve LV12 were automatically operated, and the set liquid level was 40%. When the temperature at the top outlet of the high-pressure synthetic gas separator is reduced to-165 ℃, slowly opening the valve HV10B to full open, and increasing the pressure of the valve PV107B to normal production pressure; at the moment, a valve HV10A is gradually opened to slowly increase the flow rate of the high-pressure synthesis gas into the cryogenic separation system, the maximum temperature reduction speed of the outlet at the top end of the high-pressure synthesis gas separator is controlled to be 10 ℃/h, meanwhile, the temperature difference TD305 between the liquid nitrogen inlet in the boundary area of the medium-pressure CO condenser and the process gas inlet passing through the medium-pressure CO condenser is controlled to be less than 10 ℃, and the equipment is prevented from being supercooled until the temperature at the outlet at the top end of the high-.

The opening degree of the control valve LV20 is unchanged, the liquid level is controlled to maintain the rising speed at 0.5%/min, and the liquid level lifting speeds of the high-pressure synthetic gas separator and the medium-pressure synthetic gas separator are maintained at 0.5%/min; high-pressure synthetic gas separator, medium-pressure synthetic gas separator and CO/N₂When the liquid levels of the tower separation tower, the liquid CO buffer tank and the liquid CO thermosiphon tank are established to be 40-50%, the operation is normal.

When the system is overhauled, the whole system needs to be shut down. When parking and maintenance are carried out, the method is also suitable for unfreezing and cold-state driving of the embodiment when the whole device is unfrozen and driven after maintenance, and only the CO/N is restarted in the unfreezing process₂And (4) a compressor is used.

As can be seen from the above, the cold-state driving method of the cryogenic separation device provided by the invention is used for driving under the cold-state condition, so that the driving time is obviously shortened, the energy resource consumption is reduced, and the social and economic benefits are good.