阅读说明：本技术 一种多喷嘴粉浆气化炉在线切换方法 (online switching method for multi-nozzle slurry gasification furnace ) 是由 付伟贤 于 2019-08-19 设计创作，主要内容包括：本发明提供了一种多喷嘴粉浆气化炉在线切换方法。该方法包括如下步骤：粉煤投料步骤,对第二气化炉进行升压至预设压力后,将第二粉煤烧嘴投料、升压,并将第二粉煤烧嘴产生的合成气并网后,将第一水煤浆烧嘴组或第二水煤浆烧嘴组逐渐退出运行；水煤浆投料步骤,将第三水煤浆烧嘴组和第四水煤浆烧嘴组逐组进行投料后,并且,在第三水煤浆烧嘴组或第四水煤浆烧嘴组进行投料时,将第二水煤浆烧嘴组和第一水煤浆烧嘴组中的未退出运行的一组、第一粉煤烧嘴中的一组退出运行,以完成气化炉的切换。本发明采用备用气化炉在低压下粉煤烧嘴先投料的方式,避免粉煤高压循环减压过程中温度过低水分析出的问题,进而保证了备用气化炉内粉煤物料的投料成功。(The invention provides an on-line switching method of a multi-nozzle slurry gasification furnace. The method comprises the following steps: a pulverized coal feeding step, namely after the pressure of the second gasification furnace is increased to a preset pressure, feeding and increasing the pressure of a second pulverized coal burner, and gradually withdrawing the first coal water slurry burner group or the second coal water slurry burner group from operation after synthesis gas generated by the second pulverized coal burner is combined with the power grid; and a coal water slurry feeding step, namely feeding the third coal water slurry burner group and the fourth coal water slurry burner group one by one, and when feeding the third coal water slurry burner group or the fourth coal water slurry burner group, withdrawing one of the second coal water slurry burner group and the first coal water slurry burner group which does not withdraw from operation and one of the first pulverized coal burner group from operation so as to complete the switching of the gasification furnace. According to the invention, a mode that the standby gasification furnace firstly feeds the pulverized coal burner under low pressure is adopted, so that the problem of excessive low-temperature water analysis in the high-pressure circulating decompression process of the pulverized coal is avoided, and the successful feeding of the pulverized coal material in the standby gasification furnace is further ensured.)

1. an on-line switching method of a multi-nozzle slurry gasification furnace is characterized in that,

The online cutting system of the multi-nozzle slurry gasification furnace comprises: a first gasification system and a second gasification system; the first gasification system comprises a first gasification furnace, and the second gasification system comprises a second gasification furnace; the first gasification furnace is provided with a first coal water slurry burner group, a second coal water slurry burner group and a first pulverized coal burner; a third coal water slurry burner group, a fourth coal water slurry burner group and a second pulverized coal burner are arranged on the second gasification furnace;

switching a first gasification system in operation to a second gasification system in standby, comprising the steps of:

A pulverized coal feeding step, namely after the pressure of the second gasification furnace is increased to a preset pressure, feeding and increasing the pressure of a second pulverized coal burner, and gradually withdrawing the first coal water slurry burner group or the second coal water slurry burner group from operation after synthesis gas generated by the second pulverized coal burner is combined with the power grid;

And a coal water slurry feeding step, namely feeding the third coal water slurry burner group and the fourth coal water slurry burner group one by one, and after feeding the third coal water slurry burner group or the fourth coal water slurry burner group, withdrawing one group of the second coal water slurry burner group and the first coal water slurry burner group which do not withdraw from operation and withdrawing the first pulverized coal burner from operation so as to complete the switching of the gasification furnace.

2. The on-line switching method of the multi-nozzle slurry gasification furnace according to claim 1, wherein the coal water slurry feeding step comprises:

A primary feeding substep, namely feeding any one of a third coal water slurry burner group and a fourth coal water slurry burner group, and gradually withdrawing one of a second coal water slurry burner group and a first coal water slurry burner group which does not withdraw from operation;

and a feeding substep, namely feeding a group which does not operate in the third coal water slurry burner group and the fourth coal water slurry burner group, and withdrawing the first pulverized coal burner from operation.

3. The multi-nozzle slurry gasification furnace on-line switching method according to claim 2, wherein the primary charging sub-step comprises:

And after feeding any one of the third coal water slurry burner group and the fourth coal water slurry burner group, adjusting the pressure of the second gasification system to be higher than the pressure threshold of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace, gradually withdrawing one of the second coal water slurry burner group and the first coal water slurry burner group which does not withdraw from operation, and adjusting the pressure of the first gasification system to ensure that the first gasification system operates stably.

4. The multi-nozzle slurry gasification furnace on-line switching method according to claim 2, wherein the re-feeding sub-step comprises:

And after feeding the group of the third coal water slurry burner group and the fourth coal water slurry burner group which do not operate, adjusting the pressure of the second gasification system to enable the pressure to be higher than the pressure threshold of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace, gradually withdrawing the first pulverized coal burner from operation, and adjusting the pressure of the first gasification system to enable the first gasification system to operate stably.

5. the multi-nozzle slurry gasification furnace on-line switching method according to claim 2, further comprising the following sub-steps after the re-feeding sub-step:

and a post-processing substep, namely stopping the synchronization of the synthesis gas generated by the first gasification furnace and stopping the emptying of the second gasification system, and finishing the on-line switching of the gasification systems.

6. The multi-nozzle slip gasifier on-line switching method according to any one of claims 1 to 5,

In the pulverized coal feeding step, after the pressure of the second gasification furnace is increased to a preset pressure, the second pulverized coal burner is fed and pressurized, and the pulverized coal feeding step comprises the following steps:

and after the second gasification system is emptied and the second pulverized coal burner is fed to operate, gradually stopping emptying of the second gasification system, and increasing the operating pressure of the second gasification system to be higher than the pressure threshold of a synthesis gas header pipe connected with the first gasification furnace and the second gasification furnace.

7. The on-line switching method of a multi-nozzle slip gasifier according to claim 6,

when the operation pressure of the second gasification system is increased, the pressure increasing rate of the second gasification furnace is 0.05-2 MPa/min.

8. The on-line switching method of a multi-nozzle slip gasifier according to claim 6,

In the pulverized coal feeding step, after feeding and boosting the second pulverized coal burner to the operating pressure of the second gasification system is higher than the pressure threshold of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace, the synthesis gas generated by the second pulverized coal burner is connected to the grid, and the method comprises the following steps:

And the synthesis gas produced by the second pulverized coal burner which is put into operation is merged into the synthesis gas header pipe, and the first gasification system is gradually emptied, so that the emptying amount of the first gasification system corresponds to the grid-connected amount of the second gasification system.

9. The on-line switching method of a multi-nozzle slip gasifier according to claim 8,

when the synthesis gas generated by the second pulverized coal burner is connected to the grid, the difference value between the emptying amount of the first gasification system and the grid connection amount of the second gasification system is less than or equal to 20%.

10. The on-line switching method of a multi-nozzle slip gasifier according to any one of claims 1 to 5, wherein the preset pressure is 1/8 to 1/4 of the pressure of a syngas header connected to the first gasifier and the second gasifier.

Technical Field

The invention relates to the technical field of coal gasification, in particular to an on-line switching method of a multi-nozzle slurry gasification furnace.

Background

The efficient and clean utilization of coal is a strategic choice for the sustainable development of economy and society in China, and is an important scientific and technological foundation for ensuring the stable and reliable supply of energy and the sustainable development in China. Energy and chemical systems based on coal gas are becoming hot technologies and important development directions for developing and utilizing coal efficiently, cleanly and economically in the world. Coal gasification is the conversion of coal into fuel gas or synthesis gas by reacting coal with a gasifying agent to carry out various chemical reactions.

The essence of the slurry coupling gasification technology is that slurry carbon-containing organic matters and powder carbon-containing organic matters are sprayed into the gasification furnace at the same time, so that the introduction of water is reduced, the concentration of the whole carbon-containing organic matters is indirectly improved, and the efficient co-gasification of the slurry carbon-containing organic matters and the powder carbon-containing organic matters is realized. When the gasification device of the powder slurry switches the gasification furnace in operation to the standby gasification furnace, the mode adopted at present is to stop the gasification furnace, and then the standby gasification furnace is fed, pressurized and put into the system for operation, in the process, the gasification device reduces the supply amount of the synthetic gas of one gasification furnace, the consumption time is long, a large amount of synthetic gas is generated and discharged, and the operation load of the whole production device is greatly fluctuated.

The Chinese publication number is: CN 103555370B discloses an online switching method for a multi-nozzle opposed coal gasifier, which switches an operating gasifier a to a standby gasifier B, and comprises the following operation steps: opening a synthesis gas relief valve of a system B, closing a synthesis gas merging valve of the system B, gradually closing the synthesis gas relief valve of the system B after feeding and running a burner group B1 in a gasification furnace B, increasing the running pressure of a water scrubber of the system B to 0.1-0.5MPa higher than the pressure of a synthesis gas main pipe 4, opening the synthesis gas merging valve of the system B, merging the synthesis gas produced by the burner group B1 which is put into operation into a synthesis gas main pipe 4, gradually opening the synthesis gas relief valve of the system A, keeping the pressure of the synthesis gas main pipe 4 stable, gradually reducing the running load of the burner group A1 in the gasification furnace A until the burner group is withdrawn from running, and keeping the pressure of the synthesis gas main pipe 4 stable by adjusting the opening degree of the air relief valve of the system A; feeding a B2 burner group of a B gasification furnace, merging the generated synthesis gas into a synthesis gas header pipe 4, adjusting the operation pressure of a B washing tower to be 0.1-0.5MPa higher than the pressure of the synthesis gas header pipe 4 by adjusting the opening degree of a B system synthesis gas vent valve, gradually reducing the operation load of an A2 burner group in the A gasification furnace until the A washing tower is withdrawn from operation, and adjusting the opening degree of the A system synthesis gas vent valve to adjust the operation pressure of the A washing tower to be stable; according to the operation sequence, all nozzles of the standby gasifier are finally fed and merged into the production system to run, all nozzles of the original running gasifier are withdrawn, and the switching of the gasifier is completed, namely, the coal slurry burner is firstly fed and boosted, and is merged into the production system to run, then the 1 st coal slurry burner of the original running gasifier is gradually withdrawn, the 2 nd burner of the standby gasifier is fed, and the 2 nd burner of the original running gasifier is withdrawn to realize the stable on-line switching of the gasification system.

However, for the slurry gasification furnace provided with the pulverized coal burner, the operation pressure is higher than 6MPa, for example, some operating pressures even reach 6.5MPa, when the online switching method is used for online switching, the pulverized coal is generally fed after the slurry coal slurry burner of the backup slurry gasification furnace feeds and boosts to the operation pressure, and in order to ensure smooth feeding of the pulverized coal, the pressure of the pulverized coal fed into the conveying circulation pipeline is higher than the operation pressure, so that the temperature difference between the front and the rear of the pressure reducing device during high-pressure circulation of the pulverized coal is large, the temperature of the pulverized coal is greatly reduced by the pressure reducing device, the water in the pulverized coal is separated out, the circulation pipeline is blocked, and the pressurized feeding of the pulverized coal burner under the operation pressure of the pulverized coal nozzle cannot be realized.

Disclosure of Invention

In view of the above, the invention provides an online switching method for a multi-nozzle slurry gasification furnace, and aims to solve the problem that the pressurized feeding of pulverized coal cannot be realized by the existing online tangent method.

The invention provides an on-line switching method of a multi-nozzle slurry gasification furnace, and an on-line cutting system of the multi-nozzle slurry gasification furnace comprises the following steps: a first gasification system and a second gasification system; the first gasification system comprises a first gasification furnace, the second gasification system comprises a second gasification furnace, and the first gasification furnace is provided with a first coal water slurry burner group, a second coal water slurry burner group and a first pulverized coal burner; a third coal water slurry burner group, a fourth coal water slurry burner group and a second pulverized coal burner are arranged on the second gasification furnace; switching a first gasification system in operation to a second gasification system in standby, comprising the steps of: a pulverized coal feeding step, namely after the pressure of the second gasification furnace is increased to a preset pressure, feeding and increasing the pressure of a second pulverized coal burner, and gradually withdrawing the first coal water slurry burner group or the second coal water slurry burner group from operation after synthesis gas generated by the second pulverized coal burner is combined with the power grid; and a coal water slurry feeding step, namely feeding the third coal water slurry burner group and the fourth coal water slurry burner group one by one, and after feeding the third coal water slurry burner group or the fourth coal water slurry burner group, withdrawing one of the second coal water slurry burner group and the first coal water slurry burner group which does not withdraw from operation and one of the first pulverized coal burner group from operation so as to complete the switching of the gasification furnace.

Further, according to the online switching method of the multi-nozzle slurry gasification furnace, the coal water slurry feeding step comprises the following steps: a primary feeding substep, namely feeding any one of a third coal water slurry burner group and a fourth coal water slurry burner group, and gradually withdrawing one of a second coal water slurry burner group and a first coal water slurry burner group which does not withdraw from operation; and a feeding substep, namely feeding a group which does not operate in the third coal water slurry burner group and the fourth coal water slurry burner group, and withdrawing the first pulverized coal burner from operation.

further, in the online switching method of the multi-nozzle slurry gasification furnace, the re-feeding substep comprises: and after feeding any one of the third coal water slurry burner group and the fourth coal water slurry burner group, adjusting the pressure of the second gasification system to be higher than the pressure threshold of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace, gradually withdrawing one of the second coal water slurry burner group and the first coal water slurry burner group which does not withdraw from operation, and adjusting the pressure of the first gasification system to ensure that the first gasification system operates stably.

Further, in the online switching method of the multi-nozzle slurry gasification furnace, the re-feeding substep comprises: and after feeding a group of non-operated coal water slurry burner groups in the third coal water slurry burner group and the fourth coal water slurry burner group, adjusting the pressure of the second gasification system to enable the pressure to be higher than the pressure threshold of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace, gradually withdrawing the first pulverized coal burner from operation, and adjusting the pressure of the first gasification system to enable the first gasification system to operate stably.

Further, after the primary feeding substep, the online switching method of the multi-nozzle slurry gasification furnace further comprises the following substeps: and a post-processing substep, namely stopping the synchronization of the synthesis gas generated by the first gasification furnace and finishing the on-line switching of the gasification system.

Further, in the above on-line switching method of the multi-nozzle slurry gasifier, in the step of feeding pulverized coal, after the pressure of the second gasifier is increased to a preset pressure, feeding and increasing the pressure of the second pulverized coal burner includes: and after the second gasification system is emptied and the second pulverized coal burner is fed to operate, gradually stopping emptying of the second gasification system, and increasing the operating pressure of the second gasification system to be higher than the pressure threshold of a synthesis gas header pipe connected with the first gasification furnace and the second gasification furnace.

Further, according to the online switching method of the multi-nozzle slurry gasification furnace, when the operation pressure of the second gasification system is increased, the pressure increase rate of the second gasification furnace is 0.05-2 MPa/min.

further, in the above on-line switching method of a multi-nozzle slurry gasifier, in the step of feeding pulverized coal, feeding and boosting a second pulverized coal burner until an operating pressure of the second gasifier is higher than a pressure threshold of a syngas header pipe connected to the first gasifier and the second gasifier, and then merging syngas generated by the second pulverized coal burner includes: and the synthesis gas produced by the second pulverized coal burner which is put into operation is merged into the synthesis gas header pipe, and the first gasification system is gradually emptied, so that the emptying amount of the first gasification system corresponds to the grid-connected amount of the second gasification system.

further, according to the online switching method of the multi-nozzle slurry gasification furnace, when the synthesis gas generated by the second pulverized coal burner is connected to the grid, the difference between the emptying rate of the first gasification system and the grid connection rate of the second gasification system is less than or equal to 20%.

Further, in the online switching method of the multi-nozzle slurry gasification furnace, the preset pressure is 1/8-1/4 of the pressure of a synthesis gas main pipe connected with the first gasification furnace and the second gasification furnace.

The invention provides an on-line switching method of a multi-nozzle slurry gasification furnace, which comprises the steps of firstly carrying out feeding operation on a second pulverized coal burner and then carrying out on-line switching on other nozzles, namely adopting a mode that the pulverized coal burner is fed firstly under low pressure of a backup gasification furnace; compare with adopting earlier input coal slurry in the reserve gasifier, the coal slurry of earlier input takes place gasification reaction in reserve gasifier and causes the increase of reserve gasifier internal pressure, lead to the fine coal to greatly separate out moisture at high-pressure circulation decompression in-process difference in temperature when carrying out the fine coal and throw the material again and block up the circulating line, consequently, carry out the operation of throwing of fine coal nozzle earlier in this embodiment, the follow-up operation of throwing of coal slurry of carrying on again, can avoid the problem that the temperature is too low to analyze out in the fine coal high pressure circulation decompression process, and then the unable phenomenon of throwing the material of fine coal that leads to of blocking up the circulating line in the fine coal high pressure circulation decompression process, the material of throwing of the fine coal material in reserve.

Furthermore, the mode that a nozzle arranged at the top in the operating gasification furnace is withdrawn at last is adopted, so that the influence of upward high-temperature streams generated by coal slurry nozzle impact streams of the gasification furnace on the vault can be avoided, and the top materials can generate downward pressure on the impact streams, so that a high-temperature area moves downwards, the vault is protected better, and the high-temperature damage of the vault is avoided; in addition, the last exit of the nozzle arranged at the top in the operation gasification furnace can also avoid the emptying waste of the synthesis gas, because if the burner exits first, inert gas such as nitrogen and the like is needed to be introduced to protect the burner, the fluctuation synthesis gas for avoiding the gas components is often emptied, and the emptying is wasted, so the last exit of the nozzle arranged at the top in the operation gasification furnace can avoid the introduction of the inert gas, the emptying treatment can also be avoided, and further the emptying waste of the synthesis gas is avoided.

Drawings

various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic structural diagram of an online switching system of a multi-nozzle slurry gasification furnace according to an embodiment of the present invention;

FIG. 2 is a flow chart of an online switching method of a multi-nozzle slurry gasification furnace according to an embodiment of the present invention;

FIG. 3 is a block diagram of a process of feeding the coal water slurry according to the embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Referring to fig. 1, it is a schematic structural diagram of an online switching system of a multi-nozzle slurry gasification furnace according to an embodiment of the present invention. As shown, the system includes: a first gasification system 1 and a second gasification system 2; wherein the content of the first and second substances,

The first gasification system 1 comprises a first gasification furnace 11 and a first gas purification device 12, the second gasification system 2 comprises a second gasification furnace 21 and a second gas purification device 22, and the first gasification furnace 11 and the second gasification furnace 21 are respectively connected with the first gas purification device 12 and the second gas purification device 22; the first coal gas purification device 12 is respectively connected with the torch emptying header pipe 3 and the synthesis gas header pipe 4; the second coal gas purification device 22 is respectively connected with the flare emptying header pipe 3 and the synthesis gas header pipe 4.

specifically, the first gasification furnace 11 is communicated with the first gas purification device 12, so that the synthesis gas generated by the gasification reaction in the first gasification furnace 11 is purified by the first gas purification device 12, and the synthesis gas purified by the first gas purification device 12 can be merged into the synthesis gas main pipe 4; in order to control the synthesis gas purified by the first gas purification device 12, a first synthesis gas merging valve 5 is preferably arranged between the first gas purification device 12 and the synthesis gas main pipe 4, that is, the first synthesis gas merging valve 5 is arranged on a pipeline connected between the first gas purification device 12 and the synthesis gas main pipe 4, that is, the first gas purification device 12 is connected with the synthesis gas main pipe 4 after being connected with the first synthesis gas merging valve 5. In order to control the temperature and pressure in the first gasification system 1, the first gas purification device 12 is connected to the flare emptying header 3, and preferably, a first synthesis gas emptying valve 6 is arranged between the first gas purification device 12 and the flare emptying header 3, that is, the first synthesis gas emptying valve 6 is arranged on a pipeline connected between the first gas purification device 12 and the flare emptying header 3, that is, the first gas purification device 12 is connected to the flare emptying header 3 after being connected to the first synthesis gas emptying valve 6. The second gasification system 2 is the same as the first gasification system 1, and the structure of the first gasification system 1 can be referred to, that is, the second gasification furnace 21 is communicated with the second gas purification device 22, the second gas purification device 22 is connected with the torch emptying header 3 after being connected with the second synthesis gas emptying valve 7, and the second gas purification device 22 is connected with the synthesis gas header 4 after being connected with the second synthesis gas merging valve 8.

With reference to fig. 1, the first gasification furnace 11 is provided with a first coal-water slurry burner group 111, a second coal-water slurry burner group 112 and a first pulverized coal burner 113; the second gasification furnace 21 is provided with a third coal water slurry burner group 211, a fourth coal water slurry burner group 212 and a second pulverized coal burner 213.

specifically, a first coal water slurry burner group 111 and a second coal water slurry burner group 112 which are located at the same height of the first gasification furnace 11 are arranged on the side wall of the first gasification furnace 11, and both the first coal water slurry burner group 111 and the second coal water slurry burner group 112 are composed of a pair of coal water slurry nozzles which are arranged oppositely and used for spraying slurry coal, namely, one coal water slurry burner of two coal water slurry burners in the first coal water slurry burner group 111 or the second coal water slurry burner group 112 is just sprayed towards the other coal water slurry burner, so that coal slurry sprayed by the two coal water slurry burners is impacted to form an impact flow, a baffling flow is further formed, and finally the coal slurry can be uniformly dispersed in a reaction area; meanwhile, the first coal-water slurry burners located at the same height as the first coal-water slurry burner group 111 are oppositely arranged so as to be matched with each other, and the uniform distribution of coal in the gasification furnace is effectively improved; the top of the first gasification furnace 11 is provided with a first pulverized coal burner 113 for spraying pulverized coal, the pulverized coal sprayed by the first pulverized coal burner 113 is easily carried by the uniformly dispersed coal water slurry to enter the reaction zone, and the pulverized coal is carried by the coal water slurry material flow to enter the reaction zone under the action of the impact flow and the return flow formed by the coal water slurry, so that the high-efficiency mixing of the pulverized coal and the coal water slurry is realized, the uniform distribution of the coal in the gasification furnace is effectively improved, and the co-gasification efficiency of the pulverized coal and the coal water slurry and the conversion efficiency of carbon are improved. The second gasification furnace 21 has the same structure as the first gasification furnace 11, and reference can be made to the structure of the first gasification furnace 11, so the structure of the second gasification furnace 21 will not be described in detail.

Referring to fig. 2, it is a flow chart diagram of an online switching method of a multi-nozzle slurry gasification furnace according to an embodiment of the present invention. As shown, switching a first gasification system 1 in operation to a second gasification system 2 in standby comprises the following steps:

And a pulverized coal feeding step S1, after the pressure of the second gasification furnace 21 is increased to a preset pressure, feeding and increasing the pressure of the second pulverized coal burner 213, and after the synthesis gas generated by the second pulverized coal burner 213 is combined to the grid, gradually withdrawing the first coal-water slurry burner group 111 or the second coal-water slurry burner group 112 from operation.

Specifically, first, the second gasification furnace 21 may be pressurized by introducing gas into the second gasification furnace 21, the second syngas blowoff valve 7 disposed between the second gas purification device 22 and the torch blowoff header 3, and the second syngas mixing valve 8 disposed between the second gas purification device 22 and the syngas header 4 may be closed, and then fuel gas is introduced into the second pulverized coal burner 213 to pressurize the second gasification furnace 21, although other gas may be introduced, in this embodiment, no limitation is imposed on the gas, and after the pressure is raised to a preset pressure, the introduction of gas is stopped; the preset pressure can be 1/8-1/4 of the pressure of the synthesis gas header pipe 4, and can be 0.8MPa-1MPa, for example. Then, the second synthesis gas blow-down valve 7 arranged between the second coal gas purification device 22 and the torch blow-down header pipe 3 is opened firstly, after the second pulverized coal burner 213 is fed and operated, the second synthesis gas blow-down valve 7 is gradually closed, and the operation pressure of the second gasification system 2 is increased to a pressure threshold value higher than that of the synthesis gas header pipe 4; in order to keep the system stable, it is preferable that the pressure increase rate of the second gasification furnace 21 is 0.05 to 2MPa/min when the operation pressure of the second gasification system 2 is increased; the threshold value may be 0.1-0.5MPa to ensure synchronization of the subsequent syngas in the second gasification system 2, i.e. boosting the second gasification system 2 until the pressure of the second gasification system 2 is 0.1-0.5MPa above the pressure of the syngas header 4. After the operating pressure of the second gasification system 2 is higher than the pressure threshold of the synthesis gas main pipe 4, opening a second synthesis gas merging air valve 8 arranged between the second gas purification device 22 and the synthesis gas main pipe 4, merging the synthesis gas produced by the second pulverized coal burner 213 which is put into operation into the synthesis gas main pipe 4, and meanwhile, gradually opening a first synthesis gas vent valve 6 arranged between the first gas purification device 12 and the torch vent main pipe 3 to ensure that the vent amount of the first gasification system 1 corresponds to the grid-connected amount of the second gasification system 2 in order to keep the stability of the production system; to further ensure the stability of the production system, it is preferable that the difference between the emptying amount of the first gasification system 1 and the grid-connected amount of the second gasification system 2 is less than or equal to 20% when the synthesis gas generated by the second pulverized coal burner 213 is grid-connected. And finally, after the synthesis gas of the second pulverized coal burner 213 is successfully combined with the grid, gradually withdrawing one of the first coal water slurry burner group 111 and the second coal water slurry burner group 112 from operation, and adjusting a first synthesis gas blow-down valve 6 arranged between the first gas purification device 12 and the torch blow-down header pipe 3 to enable the pressure operation of the first gasification system 1 to be stable, so that the online switching of one group of nozzles is realized.

And a coal water slurry feeding step S2, feeding the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 one by one, and after feeding the third coal water slurry burner group 211 or the fourth coal water slurry burner group 212, withdrawing one of the second coal water slurry burner group 112 and the first coal water slurry burner group 111 which is not withdrawn from operation and withdrawing one of the first pulverized coal burner group 113 from operation to complete the switching of the gasification furnace.

Specifically, after the second pulverized coal burner 213 is operated to feed the pulverized coal and the first coal-water slurry burner group 111 or the second coal-water slurry burner group 112 is withdrawn from operation in the pulverized coal feeding step S1, the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212 are gradually fed one by one, and the first pulverized coal burner 113 and one of the second coal-water slurry burner group 112 and the first coal-water slurry burner group 111 that is not withdrawn from operation are withdrawn from operation to complete the switching of the gasification furnace; after any one of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 is fed and operated, the first pulverized coal burner 113 and one of the second coal water slurry burner group 112 and the first coal water slurry burner group 111 which does not exit from operation gradually exit from operation, so that the switching of nozzles is realized; that is to say, the third coal-water slurry burner group 211 may be fed and operated first, then one of the second coal-water slurry burner group 112 and the first coal-water slurry burner group 111 that does not exit the operation and one of the first pulverized coal burner group 113 gradually exit the operation, then the fourth coal-water slurry burner group 212 may be fed and operated, and the other of the second coal-water slurry burner group 112 and the first coal-water slurry burner group 111 that does not exit the operation and the first pulverized coal burner group 113 gradually exit the operation, only after the feeding operation of one of the nozzles of the second gasification furnace 21 is ensured, one of the nozzles of the first gasification furnace 11 may gradually exit the operation, and the feeding operation sequence of the two groups of nozzles of the second gasification furnace 21 and the exit operation sequence of the two groups of nozzles of the first gasification furnace 11 are not limited in this embodiment.

Referring to fig. 3, it is a flow chart of a coal water slurry feeding step provided in the embodiment of the present invention. In order to protect the nozzles at the vault and the vault position of the gasifier, it is preferable that the first pulverized coal burner 113 disposed at the top of the first gasifier 11 is finally withdrawn from operation in the coal-water slurry feeding step S2, and of course, if other nozzles such as coal-water slurry are disposed at the top of the gasifier, the coal-water slurry feeding step S2 may also be finally withdrawn from the coal-water slurry nozzle disposed at the top, that is, as shown in the figure, the coal-water slurry feeding step S2 includes the following sub-steps:

And in the primary feeding substep S21, after feeding any one of the third coal-water-slurry nozzle group 211 and the fourth coal-water-slurry nozzle group 212, gradually withdrawing the group of the second coal-water-slurry nozzle group 112 and the first coal-water-slurry nozzle group 111 which does not withdraw from operation.

Specifically, firstly, a group of the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212 which are not operated, that is, any one of the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212 is operated. Then, after feeding any one of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212, carrying out gasification reaction on the coal water slurry fed into any one of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212, in order to enable the synthesis gas produced by any one of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 to be merged into the synthesis gas main pipe 4, adjusting a second synthesis gas vent valve 7 arranged between the second coal gas purification device 22 and the torch vent main pipe 3 to adjust the pressure of the second gasification system 2 so as to enable the pressure of the second gasification system 2 to be higher than the pressure threshold of the synthesis gas main pipe 4, namely, the pressure of the second gasification system 2 is kept higher than the pressure threshold of the synthesis gas main pipe 4; namely, the opening degree of a second synthesis gas emptying valve 7 is adjusted to keep the pressure of the second gasification system 2 higher than the pressure of a synthesis gas main pipe 4 by 0.1-0.5 MPa; and after a group of non-operated feeding materials in the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212 are operated, gradually withdrawing the group of non-withdrawn operation in the second coal-water slurry burner group 112 and the first coal-water slurry burner group 111 from operation, and adjusting the pressure of the first gasification system 1 to stabilize the pressure operation of the first gasification system 1, the pressure operation of the first gasification system 1 can be stabilized by adjusting the first synthesis gas blow-down valve 6 arranged between the first gas purification device 12 and the torch blow-down header pipe 3, that is, adjusting the opening degree of the first synthesis gas blow-down valve 6 to keep the pressure operation of the first gasification system 1 stable, so as to realize the on-line switching of the second group of nozzles.

and a feeding substep S22, feeding the group which is not operated in the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212, and withdrawing the first pulverized coal burner 113 from operation.

specifically, firstly, one of the third coal-water slurry burner group 211 and the fourth coal-water slurry burner group 212 which is not operated is fed, that is, the other of the third coal-water slurry burner group 211 or the fourth coal-water slurry burner group 212 is fed. Then, after a group of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 which do not operate is fed to operate, a group of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 which do not operate is fed to perform a gasification reaction, in order to enable a group of synthesis gas produced by a group of the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 which do not operate to merge into the synthesis gas main pipe 4, the pressure of the second gasification system 2 can be adjusted by adjusting a second synthesis gas air release valve 7 arranged between the second coal gas purification device 22 and the flare air release main pipe 3 so as to enable the pressure of the second gasification system 2 to be kept higher than the pressure threshold of the synthesis gas main pipe 4, namely, the pressure of the second gasification system 2 is ensured to be higher than the pressure threshold of the synthesis gas main pipe 4; that is, the opening degree of the second synthesis gas emptying valve 7 is adjusted to keep the pressure of the second gasification system 2 higher than the pressure of the synthesis gas main pipe 4 by 0.1-0.5 MPa; and after a group of non-operated feeding materials in the third coal water slurry burner group 211 and the fourth coal water slurry burner group 212 are operated, the first pulverized coal burner 113 is gradually withdrawn from operation, the pressure of the first gasification system 1 is adjusted by adjusting the first synthesis gas blow-down valve 6 arranged between the first coal gas purification device 12 and the torch blow-down header pipe 3, so that the first gasification system 1 operates stably, namely the opening of the first synthesis gas blow-down valve 6 is adjusted to keep the pressure operation of the first gasification system 1 stable, and thus the on-line switching of the third group of nozzles is realized.

and a post-processing substep S23, stopping the synchronization of the synthesis gas generated by the first gasification furnace and the emptying of the second gasification system, and finishing the online switching of the gasification systems.

Specifically, after the online switching of the three groups of nozzles is completed, the second syngas emptying valve 7 and the first syngas merging valve 5 are closed to stop the emptying of the second gasification furnace of the second gasification system 2 and the synchronization of the syngas generated by the first gasification furnace 11, so that the standby second gasification system 2 completely enters the running state, the running first gasification system 1 completely exits from running, and the online switching of the gasification systems is completed.

in summary, in the online switching method of the multi-nozzle slurry gasifier provided in this embodiment, the second pulverized coal burner 213 is first subjected to the feeding operation, and then the online switching of other nozzles is performed, that is, a manner that the pulverized coal burner is fed first under low pressure by the backup gasifier is adopted; and if the coal water slurry is fed firstly, compared with the coal water slurry fed in the standby gasifier firstly, the coal water slurry fed firstly is subjected to gasification reaction in the standby gasifier to increase the pressure in the standby gasifier, and then the temperature difference of the pulverized coal in the high-pressure circulating decompression process is greatly separated out to block the circulating pipeline when the pulverized coal is fed, so that the pulverized coal burner is fed firstly in the embodiment, and the coal water slurry is fed subsequently, so that the problem of low-temperature analysis in the pulverized coal high-pressure circulating decompression process can be avoided, further, the phenomenon that the pulverized coal cannot be fed due to the fact that the circulating pipeline is blocked in the pulverized coal high-pressure circulating decompression process is avoided, and the successful feeding of the pulverized coal material in the standby gasifier is ensured.

Furthermore, the mode that a nozzle arranged at the top in the operation gasification furnace, namely the first pulverized coal burner 113 is withdrawn at the last is adopted, so that the influence of upward high-temperature streams generated by coal slurry nozzle impact streams of the gasification furnace on the vault can be avoided, and the top materials can generate downward pressure on the impact streams, so that a high-temperature area moves downwards, the vault is protected better, and the high-temperature damage of the vault is avoided; in addition, the last exit of the nozzle arranged at the top in the operation gasification furnace can also avoid the emptying waste of the synthesis gas, because if the burner exits first, inert gas such as nitrogen and the like is needed to be introduced to protect the burner, the fluctuation synthesis gas for avoiding the gas components is often emptied, and the emptying is wasted, so the last exit of the nozzle arranged at the top in the operation gasification furnace can avoid the introduction of the inert gas, the emptying treatment can also be avoided, and further the emptying waste of the synthesis gas is avoided.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.