A crude synthesis gas separation and purification apparatus and method

Abstract

The present application relates to a kind of crude synthesis gas separation purification equipment and method, the present application integrates gas-solid separator in washing tower, gas-solid separator and washing tower share liquid phase area, and gas-solid separator output gas can be directly distributed once by gas-solid separator outlet, then in the process of contacting with liquid, secondary distribution is realized by tray, not only greatly reduces the setting of pipeline and corresponding detection device, makes process flow significantly shorten, but also avoids the secondary backmixing problem of solid particles in the settling process, can realize continuous separation and purification of gas-solid liquid, is advantageous to improve separation efficiency;The structure of integrated separation purification equipment is compact, small space occupation, device investment is low, and reliability is better.

Description

Technical Field

[0001] This invention relates to the field of gas-solid (liquid) separation technology, specifically to a separation and purification device and method for dust-containing crude syngas in the coal chemical industry. Background Technology

[0002] Coal is my country's primary energy source and an important chemical raw material. Coal gasification technology is the foundation of modern coal chemical industry and a crucial direction for the clean and efficient utilization of coal. Coal is gasified at high temperatures to produce crude syngas. The crude syngas produced from the gasifier contains a large number of solid particles. To improve the cleanliness of the crude syngas and ensure the smooth and stable operation of subsequent processes, further gas-solid separation is required.

[0003] Chinese invention patent application CN105062574A, entitled "A High-Efficiency Combined Dust-laden Syngas Scrubbing and Dust Removal Device and Method Thereof" (application number: CN201510544879.0), discloses a scheme consistent with traditional technology. In this scheme, the dust-laden crude syngas produced from the gasifier first enters a cyclone separator for gas-solid separation, separating large solid particles. The separated gas is then piped into a water scrubbing tower for further washing, separating fine ash. In other words, gas-solid separation and washing are performed by two separate devices. In this scheme, the cyclone separator and the water scrubbing tower are arranged independently, occupying two spans of structural frame. They need to be connected by pipes, resulting in a long process flow, a large number of devices, a large footprint, the need for related instruments and connecting pipes, and high equipment investment. Furthermore, the ash discharge port of the traditional cyclone separator is prone to clogging, and solid particles are easily back-mixed during settling, leading to incomplete gas-solid separation.

[0004] Therefore, the current crude syngas separation and purification technology needs further improvement. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a crude syngas separation and purification device that is compact in structure, occupies little space, has low investment, and avoids secondary back-mixing of solid particles during the settling process, in light of the current state of the prior art.

[0006] The second technical problem to be solved by the present invention is to provide a crude syngas separation and purification method that has a short process flow, can realize continuous separation and purification of gas, solid and liquid, and thus improve separation efficiency, in view of the current situation of the prior art.

[0007] The technical solution adopted by the present invention to solve at least one of the above-mentioned technical problems is as follows:

[0008] A crude syngas separation and purification device includes a scrubbing tower and a gas-solid separator. The inner cavity of the scrubbing tower is divided into an upper part and a lower part. The upper part is provided with a tower plate and a cyclone demister arranged from bottom to top. The top of the scrubbing tower is provided with a syngas outlet. The side wall of the upper part of the scrubbing tower is provided with a scrubbing liquid inlet pipe for inputting scrubbing liquid into the upper tower plate and an ash water inlet pipe for inputting scrubbing ash water into the middle tower plate.

[0009] The gas-solid separator is located in the lower part of the inner cavity of the scrubbing tower. The side walls of the scrubbing tower and the gas-solid separator are provided with gas inlet pipes for crude syngas to be input into the gas-solid separator. The top of the gas-solid separator has a gas outlet. The bottom of the scrubbing tower is used to contain the black water after scrubbing. The bottom of the gas-solid separator is provided with an ash discharge port extending below the black water level. The lower tower plate is connected to a downcomer extending below the black water level. The bottom of the scrubbing tower has a black water outlet.

[0010] Preferably, a gas distributor for gas dispersion is connected to the gas outlet at the top of the gas-solid separator. The gas distributor includes a central pipe connected to the gas outlet of the gas-solid separator and a distribution pipe horizontally connected to the top of the central pipe. The gas outlet on the distribution pipe is located at the end of the distribution pipe and faces downwards, corresponding to the bottom of the lowest tray. This structure improves gas distribution, and the downward direction of the gas outlet, opposite to the gas movement direction inside the scrubbing tower, increases the probability of gas-liquid phase contact, thus improving scrubbing efficiency.

[0011] Preferably, the opening angle of the gas outlet on the distribution pipe of the gas distributor is 45° to 170°.

[0012] Preferably, the lower part of the gas-solid separator is formed as a tapered section with a diameter that gradually decreases from top to bottom, the ash discharge port extends downward from the lower end of the tapered section, and the side of the washing tower is provided with a washing ash water inlet that passes through the side wall of the gas-solid separator toward the sprayed washing liquid, and the washing ash water inlet is located at the junction of the tapered section and the ash discharge port.

[0013] Preferably, the black water at the bottom of the scrubbing tower is initially clarified by a downstream black water treatment system to obtain grey water. This grey water is pressurized by a water pump and recycled in two parts. One part is used as washing grey water, entering the tray through the inlet of the scrubbing tower; the other part is used as rinsing grey water, entering the gas-solid separator through the washing grey water inlet. This grey water recycling reduces the amount of clean washing water used and lowers the amount of black water treated. To facilitate equipment manufacturing, the gas-solid separator is welded to the inner wall of the scrubbing tower via connectors on its sidewalls. The gas inlet pipe and ash discharge port of the gas-solid separator, as well as the inner wall of the scrubbing tower, are lined with wear-resistant materials.

[0014] A method for separating and purifying crude syngas includes the following steps:

[0015] Step S1: The dust-laden crude syngas exits the gasifier and enters the gas-solid separator tangentially through the gas inlet pipe for centrifugal separation;

[0016] Step S2: Large solid particles settle under the action of centrifugal force and gravity. At the same time, ash water is injected from the ash water inlet pipe. On the one hand, this wets the solid particles and washes away some of the solid particles entrained by the gas, avoiding secondary back mixing of solid particles under the entrainment of the rising airflow during the settling process, thus improving the separation effect. On the other hand, it flushes the ash discharge port to prevent blockage, which would affect the gas-solid separation efficiency. The turbid liquid with high solid content is discharged from the ash discharge port at the bottom of the gas-solid separator and enters the bottom liquid phase zone of the washing tower.

[0017] Step S3: The initially separated gas is discharged from the gas outlet at the top of the gas-solid separator and enters the gas distributor. The gas enters the distribution pipe through the central pipe, realizing the primary distribution of the gas. The outlet direction of the gas distributor is downward, which is opposite to the internal gas movement direction of the scrubbing tower, realizing the secondary distribution of the gas, thereby increasing the probability of gas-liquid phase contact and improving the scrubbing efficiency.

[0018] Step S4: Gas exits the gas distributor and enters the gas phase zone of the scrubbing tower, flowing upwards through multiple trays. It first contacts the scrubbing ash water entering from the middle of the tower, initially washing the dirtier crude syngas. It then continues upwards, making counter-current contact with the clean scrubbing liquid entering from the upper part of the tower, ensuring the purity of the crude syngas at the outlet. The two streams of scrubbing water flow downwards in stages, ensuring thorough counter-current contact between the gas and liquid phases, washing away most of the fine ash in the gas phase. The washed turbid liquid directly enters the liquid phase zone at the bottom of the tower through the downcomer.

[0019] Step S5: After the washed crude syngas passes through a cyclone demister to remove entrained liquid, it is discharged from the syngas outlet at the top of the scrubbing tower to enter the next process. All turbid liquid is discharged together from the black water outlet and enters the black water treatment system for further processing.

[0020] Compared with the prior art, the advantages of the present invention are as follows: The present invention integrates the gas-solid separator into the scrubbing tower, so that the gas-solid separator and the scrubbing tower share the liquid phase area, and the gas output from the gas-solid separator can be directly distributed through the gas-solid separator outlet for primary distribution, and then distributed again through the tower plate during the contact with the liquid. This not only greatly reduces the setting of pipelines and corresponding detection devices, significantly shortening the process flow, but also avoids the problem of secondary back-mixing of solid particles during sedimentation. It can realize continuous separation and purification of gas, solid and liquid, which is conducive to improving separation efficiency. The integrated separation and purification equipment has a compact structure, small footprint, low investment, and better reliability. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the structure of the crude syngas separation and purification equipment in an embodiment of the present invention;

[0022] Figure 2 For along Figure 1 Cross-sectional view along the AA direction;

[0023] Figure 3 This is a cross-sectional view of the gas outlet on the distribution pipe in an embodiment of the present invention;

[0024] Figure 4 This is a process flow diagram of the crude syngas separation and purification method according to an embodiment of the present invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] like Figures 1-3 As shown, the crude syngas separation and purification equipment in this embodiment includes a scrubbing tower 1 and a gas-solid separator 3. The inner cavity of the scrubbing tower 1 is divided into an upper part and a lower part. The upper part is provided with a tower plate 12 arranged from bottom to top and a cyclone demister 14. The top of the scrubbing tower 1 is provided with a syngas outlet 11. The upper side wall of the scrubbing tower 1 is provided with a scrubbing liquid inlet pipe 13 for inputting scrubbing liquid into the upper tower plate 12 and an ash water inlet pipe 18 for inputting scrubbing ash water into the lower tower plate 12. The gas-solid separator 3 is located in the lower part of the inner cavity of the scrubbing tower 1. The side walls of the scrubbing tower 1 and the gas-solid separator 2 are provided with gas inlet pipes 32 for crude syngas to be input into the gas-solid separator 3. The top of the gas-solid separator 3 has a gas outlet 31. The bottom of the scrubbing tower 1 is used to contain the black water after scrubbing. The bottom of the gas-solid separator 3 is provided with a discharge port 35 extending below the black water level 16. The lower tower plate 12 is connected to a downcomer 15 extending below the black water level. The gas-solid separator 3 and the scrubbing tower 1 share a liquid phase area. The bottom of the scrubbing tower 1 has a black water outlet 17.

[0027] A gas distributor 2 for gas dispersion is connected to the gas outlet 31 at the top of the gas-solid separator 3. The gas distributor 2 includes a central pipe 21 connected to the gas outlet 31 and a distribution pipe 22 horizontally connected to the top of the central pipe 21. The end of the distribution pipe 22 is equipped with a blind flange or cap 23. The gas outlet on the distribution pipe 22 is located at the end of the distribution pipe 22 and is arranged downwards, corresponding to the bottom of the lowest tray. This structure improves gas distribution, and the downward direction of the gas outlet, opposite to the gas movement direction inside the scrubbing tower 1, increases the probability of gas-liquid phase contact, thus improving scrubbing efficiency.

[0028] The opening angle θ corresponding to the gas outlet on the gas distributor is 45° to 170°.

[0029] The lower part of the gas-solid separator 3 is formed into a cone shape with a diameter that gradually decreases from top to bottom. The ash discharge port extends downward from the lower end of the cone. The side of the washing tower 1 is provided with a washing ash water inlet 34 that passes through the side wall of the gas-solid separator 3 and faces the sprayed washing liquid. The washing ash water inlet 34 is located at the junction of the cone and the ash discharge port 35.

[0030] To facilitate the manufacturing of the equipment, the gas-solid separator 3 is welded to the inner wall of the washing tower 1 via a connector 33 on its side wall. The gas inlet pipe 32, the ash discharge port 35 of the gas-solid separator 3, and the inner wall of the washing tower 1 are provided with wear-resistant linings.

[0031] like Figures 1-4 As shown, the crude syngas separation and purification method of this embodiment includes the following steps:

[0032] Step S1: The dust-laden crude syngas exits from the gasifier 4, passes through the gas inlet pipe 32, and enters the gas-solid separator 3 tangentially for centrifugal separation;

[0033] Step S2: Large solid particles settle under the action of centrifugal force and gravity. At the same time, ash water is injected from the ash water inlet pipe 34. On the one hand, this wets the solid particles and washes away some of the solid particles entrained by the gas, avoiding secondary back mixing of solid particles under the entrainment of the rising airflow during the settling process, thus improving the separation effect. On the other hand, it flushes the ash discharge port to prevent blockage, which would affect the gas-solid separation efficiency. The turbid liquid with high solid content is discharged from the ash discharge port 35 at the bottom of the gas-solid separator and enters the bottom liquid phase zone of the washing tower.

[0034] Step S3: The initially separated gas is discharged from the gas outlet 31 at the top of the gas-solid separator and enters the gas distributor 2. The gas enters the distribution pipe 22 through the central pipe 21, realizing the primary distribution of the gas. The outlet direction of the gas distributor 2 is downward, which is opposite to the internal gas movement direction of the scrubbing tower 1, realizing the secondary distribution of the gas, thereby increasing the probability of gas-liquid phase contact and improving the scrubbing efficiency.

[0035] Step S4: Gas exits from gas distributor 2 and enters the gas phase zone of scrubbing tower 1, flowing upwards and passing through multiple trays 12; scrubbing liquid enters the tray from the upper inlet 13 of the tower, and scrubbing ash water enters the tray from the middle ash water inlet pipe 18 of the tower under the power of pump 6, flowing downwards. The gas and liquid phases fully contact in opposite directions, washing away most of the fine ash in the gas phase. The scrubbing turbid liquid directly enters the bottom liquid phase zone of the tower through the downcomer 15.

[0036] Step S5: After the washed crude syngas passes through the cyclone demister 14 to remove the entrained liquid, it is discharged from the syngas outlet 11 at the top of the washing tower 1 to enter the next process. All the turbid liquid is discharged together from the black water outlet 17 and enters the black water treatment system 5 for further processing.

[0037] In this embodiment, the gas-solid separator 3 is integrated into the scrubbing tower 1, allowing the gas-solid separator 3 and the scrubbing tower 1 to share the liquid phase region. The gas output from the gas-solid separator 3 can be directly distributed through the outlet of the gas-solid separator 3 in the primary distribution, and then distributed again through the tower plate 12 during the contact with the liquid. This not only greatly reduces the setting of pipelines and corresponding detection devices, significantly shortening the process flow, but also avoids the problem of secondary back-mixing of solid particles during the settling process. It can achieve continuous separation and purification of gas, solid and liquid, which is beneficial to improving separation efficiency. The integrated separation and purification equipment has a compact structure, small footprint, low investment, and better reliability.

[0038] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A crude synthesis gas separation and purification apparatus comprising a scrubbing column and a gas-solids separator, characterized by: The inner cavity of the washing tower is divided into an upper part and a lower part, the upper part is provided with trays and a cyclone demister arranged from bottom to top, the top of the washing tower is provided with a synthesis gas outlet, the side wall of the upper part of the washing tower is provided with a washing liquid inlet pipe for inputting washing liquid to the upper tray and a ash water inlet pipe for inputting ash water to the lower tray; The gas-solid separator is arranged in the lower part of the inner cavity of the washing tower, the side wall of the washing tower and the gas-solid separator is provided with a gas inlet pipe for inputting the raw synthesis gas into the gas-solid separator, the top of the gas-solid separator is provided with a gas outlet, the bottom of the washing tower is used for containing the black water after washing, the bottom of the gas-solid separator is provided with an ash discharge port extending below the liquid level of the black water, and the lower tray is connected with a downcomer extending below the liquid level of the black water; the bottom of the washing tower is provided with a black water outlet; The gas outlet of the top of the gas-solid separator is connected with a gas distributor for dispersed output of the gas; the gas distributor comprises a central pipe connected with the gas outlet and a distribution pipe transversely connected to the top of the central pipe, the gas outlet on the distribution pipe is arranged at the end of the distribution pipe and downwardly, and the gas outlet corresponds to the bottom of the lowermost tray; the lower part of the gas-solid separator is shaped as a conical part with a gradually decreasing diameter from top to bottom, the ash discharge port extends downward from the lower end of the conical part, the side of the washing tower is provided with a washing ash water inlet penetrating the side wall of the gas-solid separator and facing the spraying washing liquid, and the washing ash water inlet is located at the joint of the conical part and the ash discharge port; the gas-solid separator is welded to the inner wall of the washing tower through the connecting pieces of the side wall thereof.

2. The crude synthesis gas separation and cleaning apparatus of claim 1, wherein: The opening angle of the gas outlet of the gas distributor corresponds to 45°-170°.

3. The crude synthesis gas separation and cleaning plant according to any one of claims 1 to 2, characterized in that: The gas inlet pipe, the ash discharge port of the gas-solid separator and the inner wall of the washing tower are provided with wear-resistant linings.

4. A method for separating and purifying a crude synthesis gas, characterized by, The crude synthesis gas separation and purification equipment of claim 1 or 2 or 3 comprises the following steps: Step S1: the dust-containing crude synthesis gas is discharged from the gasification furnace, enters the gas-solid separator along the tangential direction through the gas inlet pipe, and is centrifugally separated; Step S2: large solid particles are settled under the action of centrifugal force and gravity, and ash water is injected from the ash water inlet pipe, which can wet the solid particles, wash away part of the solid particles entrained by the gas, avoid secondary backmixing of the solid particles in the rising gas flow during the settling process, and flush the ash discharge port to prevent the ash discharge port from being blocked; the turbid liquid with a large solid content is discharged from the ash discharge port at the bottom of the gas-solid separator and enters the bottom liquid phase zone of the washing tower; Step S3: the preliminarily separated gas is discharged from the upper gas outlet of the gas-solid separator, enters the gas distributor, and the gas enters the distribution pipe through the central pipe to realize primary distribution of the gas; the outlet direction of the gas distributor is downward, which is opposite to the internal gas movement direction of the washing tower, to realize secondary distribution of the gas and further increase the gas-liquid phase contact probability. Step S4: The gas from the gas distributor enters the gas phase zone of the scrubbing tower, flows from bottom to top, and passes through the multiple layers of trays; the scrubbing liquid enters the trays from the upper inlet of the tower, and the scrubbing ash water enters the trays from the ash water inlet pipe in the middle of the tower, and flows from top to bottom, so that the gas-liquid phases fully contact in the opposite direction, and most of the fine ash in the gas phase is washed away. The washed turbid liquid directly enters the liquid phase zone at the bottom of the tower through the downcomer; Step S5: The washed raw synthesis gas is discharged from the synthesis gas outlet at the top of the scrubbing tower after the liquid entrained by the raw synthesis gas is removed by the cyclone plate demister, and then enters the next process. All the turbid liquid is discharged from the black water outlet and enters the black water treatment system for further processing.

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