CN107913596B

CN107913596B - Catalytic oxidation decyanation method for waste gas containing cyanogen

Info

Publication number: CN107913596B
Application number: CN201610880368.0A
Authority: CN
Inventors: 陈航宁; 郑育元; 吴粮华; 姜家乐
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2016-10-09
Filing date: 2016-10-09
Publication date: 2020-05-05
Anticipated expiration: 2036-10-09
Also published as: CN107913596A

Abstract

The invention relates to a catalytic oxidation decyanation method for cyanogen-containing waste gas. The method is used for solving the problem of low reaction efficiency of the existing catalyst. The invention removes cyanide in waste gas by adopting a cyanide-containing waste gas catalytic oxidation decyanation method, wherein cyanide in the waste gas is removed by reacting the cyanide-containing waste gas with an oxidant in a reactor in the presence of a catalytic oxidation catalyst, and the catalytic oxidation catalyst comprises the following components in parts by weight: (1) 90-99.5 parts of a catalyst carrier; (2) the technical scheme of 0.1-5 parts of ruthenium well solves the problem and can be used for removing cyanide in cyanide-containing waste gas.

Description

Catalytic oxidation decyanation method for waste gas containing cyanogen

Technical Field

The invention relates to a catalytic oxidation decyanation method for cyanogen-containing waste gas.

Technical Field

The cyanogen-containing waste gas mainly refers to organic waste gas containing hydrogen cyanide, acetonitrile, acrylonitrile and the like, and is a highly toxic pollutant harmful to biological health. At present, the decyanation method mainly comprises the technologies of absorption, adsorption, combustion, catalytic oxidation, hydrolysis and the like. Because the catalytic oxidation reaction has high efficiency and good decyanation effect, the method is widely concerned. The catalytic oxidation method can be divided into a two-step method and a one-step method according to the reaction process. The two-step process is to oxidize the cyanogen-containing waste gas into carbon dioxide, nitrogen oxide and water, and then convert the nitrogen oxide into harmless nitrogen through a denitration catalyst. The one-step process has obvious economic benefit and simpler process route, and directly converts the cyanogen-containing waste gas into carbon dioxide, water and nitrogen under the action of the catalyst.

CN102734812 discloses a method for removing cyanogen-containing waste gas, which adopts transition metal loaded mesoporous molecular sieve catalyst to carry out catalytic reaction for removing cyanogen-containing waste gas. Wherein the mesoporous molecular sieve carrier is: MCM-41, MCM-48, SBA-15, SBA-16, KIT-5 or KIT-6, and transition metal active components: one or more of Cu, Co, Cr, Mn, Ag or V, the mass ratio of the carrier to the transition metal component is 1: 0.02-0.07, and the molecular sieve catalyst is placed in a fixed bed quartzIn the reactor, under normal pressure, the temperature of the reaction furnace is raised to 350-650 ℃, and the mixed gas of cyanogen-containing waste gas, oxygen and nitrogen is used at the airspeed of 17000-24000 h^-1Introducing into a reaction furnace, and removing waste gas through catalytic combustion. The method has low removal efficiency.

CN1404904 discloses a method for removing waste gas containing HCN by a platinum rhodium catalyst, wherein the platinum rhodium catalyst is arranged in a reaction furnace, and then the temperature of the furnace is raised to 250-550 ℃; containing HCN, NH₃The waste gas mixed with tar is 5000-30000 h^-1The air speed is introduced into the reaction furnace, and air is introduced at the same time, and the volume of the air accounts for 5-50% of the total volume. The invention uses low temperature, and the gas containing nitrogen is not easy to be converted into another pollutant NO₂. However, the catalyst cost of the method is high.

CN101362051 discloses a process for treating acrylonitrile device tail gas, which is suitable for acrylonitrile waste gas discharged from an acrylonitrile device, and is characterized in that the acrylonitrile tail gas is separated from free water by a gas-liquid separator, mixed with air, and subjected to catalytic oxidation reaction by taking a noble metal honeycomb catalyst as a catalyst to convert harmful volatile organic compounds into carbon dioxide and water; and then taking the selective reduction honeycomb catalyst as a catalyst to perform selective catalytic reduction reaction with the supplemented ammonia, so as to reduce the nitrogen oxides in the tail gas into nitrogen and water. The method is complex to operate, ammonia needs to be supplemented, and the material consumption is high.

Disclosure of Invention

The invention aims to solve the technical problem of low efficiency of removing cyanide in cyanide-containing waste gas by catalytic oxidation in the prior art, and provides a novel wet oxidation treatment method of high-concentration organic wastewater, which has the advantage of high cyanide removal efficiency.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the catalytic oxidation decyanation method of cyanogen-containing waste gas comprises the following steps of reacting the cyanogen-containing waste gas with an oxidant in a reactor in the presence of a catalytic oxidation catalyst to remove cyanides in the waste gas, wherein the catalytic oxidation catalyst comprises the following components in parts by weight: (1) 90-99.5 parts of a catalyst carrier; (2) 0.1-5 parts of ruthenium.

In the above technical solution, the oxidizing agent is preferably hydrogen peroxide.

In the above technical solution, the oxidizing agent is preferably oxygen-containing gas.

In the above technical solution, the oxygen-containing gas is preferably air or oxygen-enriched gas.

In the technical scheme, the reaction temperature is preferably 280-500 ℃.

In the technical scheme, the total volume space velocity of the cyanogen-containing waste gas and the oxidant is preferably 1000-30000 h^-1。

In the above technical solution, the reactor is preferably a fixed bed reactor.

In the above technical scheme, the kind of cyanogen in the cyanogen-containing waste gas is not limited, as long as it has the effect of removing CN group in the molecule, for example, but not limited to, cyanogen ((CN)₂) Thiocyanide ((SCN)₂) Oxygen cyanide ((OCN)₂) HCN, HSCN, HOCN, saturated nitriles of C2 to C10 (such as but not limited to acetonitrile), unsaturated nitriles of C3 to C10 (such as but not limited to acrylonitrile, methacrylonitrile, benzonitrile, m-tolunitrile), and the like.

In the above technical solution, the catalyst carrier is preferably selected from TiO₂、ZrO₂、SiO₂And Al₂O₃One kind of (1).

In the above technical solution, the shape of the catalyst is preferably honeycomb type, clover type, column type or spherical type.

In the above technical scheme, the catalyst can be prepared by a preparation method comprising the following steps:

(1) mixing a solution of a compound containing ruthenium element with a carrier;

(2) and (4) roasting.

In the technical scheme, the catalyst preferably further comprises (3) 0.1-5 parts of copper, and the ruthenium and the copper have an obvious synergistic effect in the aspect of removing the cyanogen in the cyanogen-containing waste gas.

In the above technical solution, when the catalyst contains copper, the preparation method may further be a first method comprising the following steps:

(1) mixing a mixed solution of a ruthenium element-containing compound and a copper element-containing compound with a carrier;

(2) and (4) roasting.

In the above technical solution, when the catalyst contains copper, the preparation method may further be a second method comprising the following steps:

1) mixing a solution of a compound containing ruthenium element with a carrier;

2) roasting to obtain a catalyst precursor I;

3) mixing a copper element-containing compound solution with a precursor I;

4) and (4) roasting.

In the above technical solution, when the catalyst contains copper, the preparation method may further be a third method comprising the following steps:

i) mixing a copper element-containing compound solution with a carrier;

II) calcining to obtain a catalyst precursor II;

iii) mixing the solution of the compound containing the ruthenium element with the catalyst precursor II;

iv) roasting.

Surprisingly, the catalyst prepared by the second method has more outstanding effect on removing cyanogen in cyanogen-containing waste gas than the other two methods.

In the technical scheme, the roasting temperature is preferably 300-700 ℃.

In the technical scheme, the roasting time is preferably 1-6 hours.

In the above embodiment, the atmosphere for the firing is preferably an inert atmosphere or an oxidizing atmosphere.

In the above embodiment, the oxidizing atmosphere is preferably air.

In the above technical solution, the compound containing ruthenium element is preferably selected from any one of ruthenium nitrate, ruthenium chloride and ruthenium acetate.

In the above technical solution, the copper element-containing compound is preferably selected from any one of copper nitrate, copper chloride, copper sulfate and copper acetate.

It is known to the person skilled in the art that a mechanically stronger catalyst is obtained if drying is carried out before calcination, and from this point of view, a drying step is recommended before calcination. The specific temperature of drying is not limited, such as but not limited to 60-120 ℃, and further non-limiting examples may be: 70 deg.C, 80 deg.C, 90 deg.C, 100 deg.C, 110 deg.C, etc.

The technical scheme of the invention shows that the C-06 catalyst containing ruthenium and copper prepared by the invention has the reaction temperature of 380 ℃ and the space velocity of 12000h^-1The cyanide in the cyanide-containing waste gas can be effectively removed, and the acrylonitrile in the cyanide-containing waste gas is reduced from 1,925ppm to 0.8ppm after the catalytic oxidation treatment; the hydrogen cyanide is reduced from 240ppm to 1.2ppm, and the content of NOx in the tail gas is 17.4ppm, so that a better technical effect is achieved.

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention in any way.

Detailed Description

[ example 1 ]

1. Catalyst preparation

In weight ratio, ZrO₂Ru and Cu 96:0.2:3.8, and catalyst A-01 was prepared.

Adding 96 parts of ZrO₂The catalyst carrier was impregnated at room temperature with RuCl equivalent to 0.2 parts Ru₃And 3.8 parts of Cu (NO)₃)₂The catalyst A-01 is obtained by roasting the catalyst A-01 in an air atmosphere at 400 ℃ after the catalyst A-01 is dried in an aqueous solution overnight at 80 ℃. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-01 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 2 ]

1. Catalyst preparation

In terms of weight ratio, SiO₂Ru and Cu in a ratio of 96:0.2:3.8 to prepare the catalyst A-02.

Mixing 96 parts of SiO₂The catalyst carrier was impregnated at room temperature with RuCl equivalent to 0.2 parts Ru₃And 3.8 parts of Cu (NO)₃)₂The catalyst A-02 is obtained by roasting the catalyst A-02 in an air atmosphere at 400 ℃ after the catalyst A is dried at 80 ℃ overnight in an aqueous solution. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-02 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 3 ]

1. Catalyst preparation

Calculated by weight ratio, Al₂O₃Ru and Cu are respectively 96:0.2:3.8, and the catalyst A-03 is prepared.

Mixing 96 parts of Al₂O₃The catalyst carrier was impregnated at room temperature with RuCl equivalent to 0.2 parts Ru₃And 3.8 parts of Cu (NO)₃)₂The catalyst A-03 is obtained by standing overnight in an aqueous solution, drying at 80 ℃ and then roasting for 4 hours at 400 ℃ in an air atmosphere. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-03 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 4 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru and Cu 96:0.2:3.8, and catalyst A-04 was prepared.

96 parts of TiO₂The catalyst carrier was impregnated at room temperature with RuCl equivalent to 0.2 parts Ru₃And 3.8 parts of Cu (NO)₃)₂The catalyst A-04 is obtained by calcining the catalyst A-04 in an air atmosphere at 400 ℃ after the catalyst A-04 is dried in an aqueous solution overnight at 80 ℃. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-04 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 5 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru and Cu 96:0.2:3.8, catalyst A-05 was prepared.

96 parts of TiO₂The catalyst carrier was impregnated with Ru (NO) equivalent to 0.2 part Ru at room temperature₃)₃And 3.8 parts of Cu (NO)₃)₂The catalyst A-05 is obtained by roasting the catalyst in an air atmosphere at 400 ℃ for 4 hours after the catalyst is dried in an aqueous solution at 80 ℃. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-05 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 6 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru and Cu 96:0.2:3.8, and catalyst A-06 was prepared.

96 parts of TiO₂The catalyst carrier was impregnated with Ru (NO) equivalent to 0.2 part Ru at room temperature₃)₃And (3) standing overnight in the aqueous solution, drying at 80 ℃, and roasting for 4 hours at 400 ℃ in an air atmosphere to obtain a catalyst precursor B-06. B-06 was immersed in Cu (NO) equivalent to 3.8 parts of Cu₃)₂The catalyst A-06 is obtained by drying the catalyst in water solution overnight at 80 ℃ and then roasting the dried catalyst for 4 hours in air atmosphere at 400 ℃. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-06 catalyst. The reaction temperature in the reactor is380 ℃ and reaction space velocity of 12000h^-1. The reaction results are shown in Table 2.

[ example 7 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru and Cu are respectively 96:0.2:3.8, and the catalyst A-07 is prepared.

96 parts of TiO₂The catalyst carrier was impregnated with Cu (NO) equivalent to 3.8 parts of Cu at room temperature₃)₂And (3) standing overnight in the aqueous solution, drying at 80 ℃, and roasting for 4 hours at 400 ℃ in an air atmosphere to obtain a catalyst precursor B-07. B-07 was impregnated with Ru (NO) equivalent to 0.2 part of Ru₃)₃The catalyst A-07 is obtained by calcining the catalyst A-07 in an air atmosphere at 400 ℃ after the catalyst A is dried at 80 ℃ overnight in an aqueous solution. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-07 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ example 8 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru and Cu 96:0.2:3.8, and catalyst A-08 was prepared.

96 parts of TiO₂The catalyst carrier was impregnated with Ru (NO) equivalent to 0.4 part Ru at room temperature₃)₃And (3) standing overnight in the aqueous solution, drying at 80 ℃, and roasting for 4 hours at 400 ℃ in an air atmosphere to obtain a catalyst precursor B-08. B-08 was impregnated with Cu (NO) equivalent to 3.6 parts of Cu₃)₂The catalyst A-08 is obtained by roasting the catalyst A-08 in an air atmosphere at 400 ℃ after the catalyst A is dried at 80 ℃ overnight. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and then passed through a fixed bed reactor packed with 800ml of a-08 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ COMPARATIVE EXAMPLE 1 ]

1. Catalyst preparation

In weight ratio, TiO₂Ru 96:4 catalyst D-01 was prepared.

96 parts of TiO₂The catalyst carrier is impregnated with Ru (NO) equivalent to 4 parts of Ru at room temperature₃)₃The catalyst D-01 is obtained by roasting the catalyst in an air atmosphere at 400 ℃ for 4 hours after the catalyst is dried in an aqueous solution at 80 ℃. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and passed through a fixed bed reactor packed with 800mLD-01 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

[ COMPARATIVE EXAMPLE 2 ]

1. Catalyst preparation

In weight ratio, TiO₂Cu of 96:4, catalyst D-02 was prepared.

96 parts of TiO₂The catalyst carrier was impregnated with Cu (NO) equivalent to 4 parts of Cu at room temperature₃)₂The catalyst D-02 was obtained by drying the aqueous solution overnight at 80 ℃ and then calcining the dried product in an air atmosphere at 400 ℃ for 4 hours. The catalyst formulation is shown in table 1.

2. Catalyst evaluation

Cyanogen-containing waste gas (acrylonitrile 1925ppm, hydrogen cyanide 240ppm) and air were mixed in a ratio of 1: 5 and passed through a fixed bed reactor packed with 800mLD-02 catalyst. The reaction temperature in the reactor is 380 ℃, and the reaction space velocity is 12000h^-1. The reaction results are shown in Table 2.

TABLE 1 formulation of the catalyst

Examples	Catalyst and process for preparing same	Catalyst formulation	The mass ratio of each component
				Example 1	A-01	ZrO₂:Ru:Cu	96:0.2:3.8
Example 2	A-02	SiO₂:Ru:Cu	96:0.2:3.8
				Example 3	A-03	Al₂O₃:Ru:Cu	96:0.2:3.8
Example 4	A-04	TiO₂:Ru:Cu	96:0.2:3.8
				Example 5	A-05	TiO₂:Ru:Cu	96:0.2:3.8
Example 6	A-06	TiO₂:Ru:Cu	96:0.2:3.8
				Example 7	A-07	TiO₂:Ru:Cu	96:0.2:3.8
Example 8	A-08	TiO₂:Ru:Cu	96:0.4:3.6
				Comparative example 1	D-01	TiO₂:Ru	96:4
Comparative example 2	D-02	TiO₂:Cu	96:4

TABLE 2 reaction results

Claims

1. The catalytic oxidation decyanation method of cyanogen-containing waste gas comprises the following steps of reacting the cyanogen-containing waste gas with an oxidant in a reactor in the presence of a catalytic oxidation catalyst to remove cyanides in the waste gas, wherein the catalytic oxidation catalyst comprises the following components in parts by weight: (1) 90-99.5 parts of a catalyst carrier; (2) 0.1-5 parts of ruthenium; (3) 0.1-5 parts of copper; the catalyst is prepared by a preparation method comprising the following steps:

1) mixing a solution of a compound containing ruthenium element with a carrier;

2) roasting to obtain a catalyst precursor I;

3) mixing a copper element-containing compound solution with a precursor I;

4) and (4) roasting.

2. The decyanation process of claim 1, wherein the oxidizing agent is hydrogen peroxide.

3. The decyanation process of claim 1, wherein said oxidizing agent is an oxygen-containing gas.

4. A decyanation process according to claim 3, characterized in that the oxygen containing gas is air or oxygen enriched.

5. A decyanation process according to claim 3, wherein the reaction temperature is 280 to 500 ℃.

6. The decyanation method according to claim 3, wherein the total volume space velocity of the cyanogen-containing waste gas and the oxidant is 1000 to 30000h^-1。

7. The decyanation process of claim 1, wherein the reactor is a fixed bed reactor.

8. The decyanation process of claim 1, wherein the catalyst support is selected from the group consisting of TiO₂、ZrO₂、SiO₂And Al₂O₃One kind of (1).

9. The decyanation process of claim 1, wherein said catalyst is in the form of honeycomb, clover, cylinder or sphere.