A method and device for separating cyanide in a nitrogen-transported coal powder process

Abstract

The present invention relates to the technical field of cyanide separation and removal, and in particular to a method and device for separating cyanide in a nitrogen-transported coal powder process, comprising: conveying coal powder to a gasifier through high-pressure nitrogen, reacting with high-pressure oxygen also conveyed to the gasifier to generate 3MPa synthesis gas; removing dust from the synthesis gas; and passing the dust-removed synthesis gas into a two-stage hydrogen cyanide catalytic unit. The method and device for separating cyanide in a nitrogen-transported coal powder process can treat a portion of cyanide on one side of the synthesis gas through a hydrogen cyanide catalytic unit, thereby preventing a large amount of cyanide from entering a water treatment system, greatly reducing the pressure on subsequent treatment of cyanide, and even achieving standard discharge.

Description

Technical Field

[0001] The invention relates to the technical field of cyanide separation and removal, and in particular to a cyanide separation method and device in a nitrogen-transported coal powder process. Background Art

[0002] The pulverized coal pressurized gasification process uses nitrogen separated by air separation to transport pulverized coal. In this process, highly toxic cyanide is generated and needs to be handled with caution. At present, the treatment of cyanide waste liquid is mainly determined by the source, nature, water volume, cyanide existence form and cyanide content of the wastewater. In real life, cyanide in water is generally treated in the water treatment stage, which has the problems of large floor space, small processing capacity, high consumption cost, etc. For this reason, the present invention provides a method and device for separating cyanide in the process of nitrogen transporting pulverized coal. Summary of the invention

[0003] In view of the problems existing in the above-mentioned existing cyanide separation method and device in the process of nitrogen conveying coal powder, the present invention is proposed.

[0004] Therefore, one of the objects of the present invention is to provide a method for separating cyanide in a nitrogen-transported coal powder process, the purpose of which is to improve the efficiency of cyanide treatment, reduce the cyanide content in wastewater, and reduce the subsequent cyanide treatment pressure.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for separating cyanide in a nitrogen-transported coal powder process, comprising:

[0006] The pulverized coal is transported to the gasifier through nitrogen and reacts with oxygen also transported to the gasifier to generate 3MPa synthesis gas;

[0007] By dust removal from the syngas; and,

[0008] The dedusted synthesis gas is passed into a two-stage hydrogen cyanide catalytic unit.

[0009] As a preferred scheme of the cyanide separation method in the nitrogen conveying coal powder process of the present invention, the synthesis gas is introduced into a dust removal unit for dust removal, and the dust content in the synthesis gas after dust removal is less than 3 mg / Nm3.

[0010] As a preferred solution of the cyanide separation method in the nitrogen conveying pulverized coal process of the present invention, the steam generated in the gasifier is introduced into the dust removal unit to mix with the synthesis gas to cool the synthesis gas.

[0011] As a preferred solution of the cyanide separation method in the nitrogen conveying coal powder process of the present invention, the temperature of the synthesis gas after cooling is lower than 120°.

[0012] As a preferred solution of the cyanide separation method in the nitrogen conveying coal powder process of the present invention, the hydrogen cyanide catalytic unit is arranged in two sections, the upper section is provided with a multifunctional hydrolysis catalyst, and the lower section is provided with a carbonyl sulfide catalyst.

[0013] The beneficial effect of this method is that a portion of the cyanide is treated through the hydrogen cyanide catalytic unit on the synthesis gas side, which can prevent a large amount of cyanide from entering the water treatment system, greatly reducing the pressure on subsequent cyanide treatment and even achieving standard discharge.

[0014] Another object of the present invention is to provide a cyanide separation device in a nitrogen-transported coal powder process, the purpose of which is to improve the efficiency of cyanide treatment, reduce the cyanide content in wastewater, and reduce the subsequent cyanide treatment pressure.

[0015] In order to solve the above technical problems, the present invention provides the following technical solutions: a cyanide separation device in a nitrogen-transported coal powder process, used to perform a cyanide separation method in a nitrogen-transported coal powder process, comprising:

[0016] Gasifier;

[0017] A dust removal unit is connected to the gasifier, and the synthesis gas generated in the gasifier enters the dust removal unit for dust removal;

[0018] The hydrogen cyanide catalytic unit is connected to the dust removal unit, and a multifunctional hydrolysis catalyst is arranged in the upper section of the hydrogen cyanide catalytic unit, and a carbonyl sulfide catalyst is arranged in the lower section. The synthesis gas after dust removal enters the hydrogen cyanide catalytic unit for cyanide separation.

[0019] As a preferred solution of the cyanide separation device in the nitrogen conveying coal powder process of the present invention, wherein: the dust removal unit includes a rotary separator connected to the gasifier, a first lock bucket connected to the rotary separator, and a second lock bucket connected to the first lock bucket;

[0020] The hydrogen cyanide catalytic unit is connected to the rotary separator.

[0021] As a preferred solution of the cyanide separation device in the nitrogen-transported coal powder process of the present invention, wherein: the hydrogen cyanide catalytic units are provided with two and are arranged horizontally;

[0022] The rotary separator is connected to the two hydrogen cyanide catalytic units.

[0023] As a preferred solution of the cyanide separation device in the nitrogen conveying coal powder process of the present invention, the hydrogen cyanide catalytic unit is connected to a water washing device.

[0024] As a preferred solution of the cyanide separation device in the nitrogen conveying pulverized coal process of the present invention, the top of the gasifier is connected to a steam drum, and one end of the steam drum is connected to a rotary separator.

[0025] The beneficial effects of the present invention are as follows: by passing the synthesis gas generated in the gasifier into the hydrogen cyanide catalytic unit for cyanide treatment after dust removal, a large amount of cyanide can be prevented from entering the water treatment system, greatly reducing the pressure on subsequent cyanide treatment, and even achieving emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0027] Figure 1 The figure is a schematic diagram of the overall structure of the cyanide separation device in the process of nitrogen transporting pulverized coal of the present invention.

[0028] Description of the drawings: 100, gasifier; 200, dust removal unit; 300, hydrogen cyanide catalytic unit; 201, rotary separator; 202, first lock hopper tank; 203, second lock hopper tank; 400, water washing device; 500, steam drum. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0033] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a method for separating cyanide in a nitrogen-transported coal powder process, the method comprising:

[0034] S1. The pulverized coal is transported to the gasifier 100 through nitrogen, and reacts with oxygen also transported to the gasifier 100 to generate 3MPa synthesis gas;

[0035] The pulverized coal is transported to the gasifier 100 by high-pressure nitrogen, and reacts with high-pressure oxygen also transported to the gasifier 100 to generate a synthesis gas of about 3 MPa.

[0036] S2. by removing dust from the synthesis gas;

[0037] The synthesis gas generated by the reaction in the gasifier 100 is introduced into the dust removal unit 200 for dust removal, and the dust content in the synthesis gas after the dust removal does not exceed 3 mg / Nm3.

[0038] S3. The dedusted synthesis gas is passed into the two-stage hydrogen cyanide catalytic unit 300;

[0039] The dedusted synthesis gas is introduced into a two-stage hydrogen cyanide catalytic unit 300 for cyanide treatment, wherein the hydrogen cyanide catalytic unit 300 is arranged in two stages, wherein a multifunctional hydrolysis catalyst is arranged in the upper stage and a carbonyl sulfide catalyst is arranged in the lower stage.

[0040] A multifunctional hydrolysis catalyst is arranged at the upper section of the hydrogen cyanide catalytic unit 300, which converts part of the carbonyl sulfide into hydrogen sulfide and converts the hydrogen cyanide into ammonia through a hydrolysis reaction. The hydrogen cyanide separation rate can reach 80%. The synthesis gas continues to pass through the carbonyl sulfide catalyst at the lower section to continue to convert the remaining carbonyl sulfide into hydrogen sulfide. The overall carbonyl sulfide separation rate can reach more than 90%.

[0041] The synthesis gas after catalytic cyanide separation will enter the subsequent water treatment system again. Since part of the cyanide is treated on the synthesis gas side, the cyanide content in the wastewater discharged from the water washing device is greatly reduced. The subsequent treatment of cyanide reduces a lot of pressure and can even meet the discharge standards, solving the problems of treating cyanide in water in the existing water treatment stage, which has large footprint, small processing capacity, high consumption cost, etc. The synthesis gas side is the stage where the synthesis gas has not passed through the water washing device.

[0042] Furthermore, during the dedusting stage of the synthesis gas, the synthesis gas in the dedusting unit 200 can be cooled simultaneously, and the temperature of the synthesis gas after cooling is lower than 120°, so as to avoid the deactivation of the multifunctional hydrolysis catalyst in the subsequent decyanation device.

[0043] It can cool down the dust removal unit 200 by spraying water mist, or pass the steam generated in the gasifier 100 into the dust removal unit 200, so that the steam merges with the synthesis gas in the dust removal unit 200, and cools down the synthesis gas in the dust removal unit 200. At the same time, the steam can further adsorb the dust in the synthesis gas when merging with the synthesis gas, thereby improving the dust removal efficiency while cooling the synthesis gas.

[0044] Example 2, reference Figure 1 , which is a second embodiment of the present invention, provides a cyanide separation device in a nitrogen-transported coal powder process, the device comprising a gasifier 100, a dust removal unit 200 and a hydrogen cyanide catalytic unit 300.

[0045] The pulverized coal is transported to the gasifier 100 by high-pressure nitrogen, and reacts with high-pressure oxygen also transported to the gasifier 100 to generate a synthesis gas of about 3 MPa; the dust removal unit 200 is connected to the gasifier 100, and the synthesis gas generated in the gasifier 100 enters the dust removal unit 200 for dust removal; the hydrogen cyanide catalytic unit 300 is connected to the dust removal unit 200, and a multifunctional hydrolysis catalyst is arranged in the upper section of the hydrogen cyanide catalytic unit 300, and a carbonyl sulfide catalyst is arranged in the lower section, and the synthesis gas after dust removal enters the hydrogen cyanide catalytic unit 300 for cyanide separation.

[0046] A multifunctional hydrolysis catalyst is arranged at the upper section of the hydrogen cyanide catalytic unit 300, which converts part of the carbonyl sulfide into hydrogen sulfide and converts the hydrogen cyanide into ammonia through a hydrolysis reaction. The hydrogen cyanide separation rate can reach 80%. The synthesis gas continues to pass through the carbonyl sulfide catalyst at the lower section to continue to convert the remaining carbonyl sulfide into hydrogen sulfide. The overall carbonyl sulfide separation rate can reach more than 90%.

[0047] The synthesis gas after catalytic cyanide separation will enter the subsequent water treatment system again. Since part of the cyanide is treated on the synthesis gas side, the cyanide content in the wastewater system is greatly reduced. The subsequent treatment of cyanide is greatly relieved and can even meet the discharge standards, solving the problems of existing water treatment stages in treating cyanide in water, such as large footprint, small treatment capacity, and high consumption costs.

[0048] Furthermore, two hydrogen cyanide catalytic units 300 are provided and arranged horizontally; the rotary separator 201 is connected to the two hydrogen cyanide catalytic units 300, and the two hydrogen cyanide catalytic units 300 are arranged in a one-in-use and one-in-standby configuration. When the catalyst of one of the hydrogen cyanide catalytic units 300 fails, the catalyst can be quickly converted into the second standby hydrogen cyanide catalytic unit 300; and the horizontal hydrogen cyanide catalytic unit 300 has a larger flow area and smaller resistance than the vertical one, so the pressure increase will not exceed 100 kPa, thereby ensuring the normal operation of the gasifier 100, because the environment of the gasifier 100 will change after the pressure increases, which will cause the gasifier 100 to fail to operate normally.

[0049] The dust removal unit 200 includes a rotary separator 201 connected to the gasifier 100 , a first lock bucket 202 connected to the rotary separator 201 , and a second lock bucket 203 connected to the first lock bucket 202 ; the hydrogen cyanide catalytic unit 300 is connected to the rotary separator 201 .

[0050] When the dust removal unit 200 is working: the dust in the synthesis gas is separated by the rotary separator 201. When the rotary separator 201 is connected to the first lock bucket 202, the dust collected by the rotary separator 201 enters the first lock bucket 202. When the dust in the first lock bucket 202 reaches a certain amount, the channel between the rotary separator 201 and the first lock bucket 202 is closed, and the second lock bucket 203 is pressurized so that the pressure between it and the first lock bucket 202 is equal. At this time, the channel between the rotary separator 201 and the first lock bucket 202 is closed, and the channel between the first lock bucket 202 and the second lock bucket 203 is connected. The dust will enter the second lock bucket 203, the channel between the first lock bucket 202 and the second lock bucket 203 is closed, the pressure of the second lock bucket 203 is relieved, and the dust in the second lock bucket 203 is removed; the whole process is repeated for continuous dust removal.

[0051] During use: coal powder is transported to the gasifier 100 by high-pressure nitrogen, and reacts with high-pressure oxygen also transported to the gasifier 100 to generate synthesis gas of about 3 MPa. The synthesis gas enters the rotary separator 201 to rotate and separate the dust in the synthesis gas, and then enters the hydrogen cyanide catalytic unit 300 to separate cyanide.

[0052] The separated synthesis gas enters the water washing device 400 in the water treatment stage, and the synthesis gas is washed by passing water into the water washing device 400. The water washing washes out a small amount of dust and cyanide in the synthesis gas for further water treatment downstream.

[0053] Example 3, reference Figure 1 , which is the third embodiment of the present invention. This embodiment is different from the second embodiment in that a steam drum 500 is connected to the top of the gasifier 100 , and one end of the steam drum 500 is connected to the rotary separator 201 .

[0054] The steam drum 500 can collect the steam generated by the gasifier 100 and form a steam-water cycle with the gasifier 100, that is, the steam drum 500 collects the steam generated in the gasifier 100 and passes it into the rotary separator 201 to merge with the synthesis gas, and cools the synthesis gas by steam. At the same time, it can absorb dust in the synthesis gas while cooling it, thereby improving the dust removal efficiency; and the drum is also connected to an auxiliary steam manifold to recover excess steam.

[0055] The remaining structure is the same as that of Example 2.

[0056] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those features that are not relevant to implementing the invention).

[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for separating cyanide in a nitrogen-transported coal powder process, characterized in that: include, The pulverized coal is transported to a gasifier (100) via nitrogen, and reacts with oxygen also transported to the gasifier (100) to generate a synthesis gas of 3 MPa; Dust removal from syngas; and, The dedusted synthesis gas is introduced into a two-stage hydrogen cyanide catalytic unit (300) to separate cyanide; the separated synthesis gas enters a water washing device (400) in a water treatment stage, and water is introduced into the water washing device (400) to wash the synthesis gas, thereby washing out a small amount of dust and cyanide in the synthesis gas for further water treatment downstream; The synthesis gas is passed into a dust removal unit (200) for dust removal, and the dust content in the synthesis gas after the dust removal is less than 3 mg / Nm3; Passing the steam generated in the gasifier (100) into the dust removal unit (200) to mix with the synthesis gas to reduce the temperature of the synthesis gas; The temperature of the syngas after cooling is lower than 120°C, which avoids the deactivation of the multifunctional hydrolysis catalyst in the subsequent decyanation unit; The hydrogen cyanide catalytic unit (300) is divided into two sections. The upper section is provided with a multifunctional hydrolysis catalyst to convert part of the carbonyl sulfide into hydrogen sulfide while converting the hydrogen cyanide into ammonia through a hydrolysis reaction. The hydrogen cyanide separation rate can reach 80%. The lower section of the hydrogen cyanide catalytic unit (300) is provided with a carbonyl sulfide catalyst to continue to convert the remaining carbonyl sulfide into hydrogen sulfide. The overall carbonyl sulfide separation rate can reach more than 90%.

2. A cyanide separation device in a nitrogen-transported coal powder process, used to perform the cyanide separation method in a nitrogen-transported coal powder process according to claim 1, characterized in that: include; Gasifier (100); a dust removal unit (200) connected to the gasifier (100), wherein the synthesis gas generated in the gasifier (100) enters the dust removal unit (200) for dust removal; and A hydrogen cyanide catalytic unit (300) is connected to the dust removal unit (200), and a multifunctional hydrolysis catalyst is arranged at the upper section of the hydrogen cyanide catalytic unit (300), and a carbonyl sulfide catalyst is arranged at the lower section, and the synthesis gas after dust removal enters the hydrogen cyanide catalytic unit (300) for cyanide separation; The hydrogen cyanide catalytic unit (300) is connected to a water washing device (400).

3. The cyanide separation device in the nitrogen conveying coal powder process according to claim 2 is characterized in that: The dust removal unit (200) comprises a rotary separator (201) connected to the gasifier (100), a first lock hopper (202) connected to the rotary separator (201), and a second lock hopper (203) connected to the first lock hopper (202); The hydrogen cyanide catalytic unit (300) is connected to the rotary separator (201).

4. The cyanide separation device in the nitrogen conveying coal powder process according to claim 3 is characterized in that: The hydrogen cyanide catalytic units (300) are provided with two and are arranged horizontally; The rotary separator (201) is connected to the two hydrogen cyanide catalytic units (300).

5. The cyanide separation device in the nitrogen conveying coal powder process according to any one of claims 2 to 4, characterized in that: The top of the gasifier (100) is connected to a steam drum (500), and one end of the steam drum (500) is connected to a rotary separator (201).

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