CN105233649B - A kind of Complexing Iron desulfurizing agent and its application method - Google Patents

Abstract

The invention discloses a complex iron desulfurizer and a using method thereof, belonging to the technical field of gas purification. The complex iron desulfurizer contains the following components: soluble iron salt, iron salt chelating agent, sulfide absorbent, stabilizer, composite sulfur particle sedimentation agent and multifunctional corrosion inhibitor; among them, Fe ³⁺ and Fe in soluble iron salt The molar ratio of ²⁺ is 1:3~5:1; the molar ratio of chelating agent to iron salt is 1.2:1~3:1; the pH value of the solution is 8.0~9.5. The present invention combines complex iron desulfurization agent with supergravity technology, which has high desulfurization efficiency, high working sulfur capacity, stable performance of desulfurizer, good oxidation regeneration; supergravity complex iron desulfurization process is simple, gas-liquid mass transfer efficiency is high, The equipment is small in size and easy to skid. It is expected to be widely used in the removal of natural gas or associated gas H ₂ S on offshore oil and gas platforms in the future.

Description

A kind of complex iron desulfurizer and using method thereof

technical field

The invention relates to a complex iron desulfurizer and a method for using the same, belonging to the technical field of gas purification.

Background technique

There are researches on complex iron desulfurizer in the prior art:

The iron chelating agent used in the LO-CAT process desulfurization fluid developed by Wheelabrator Clean Air Systems of the United States is ethylenediaminetetraacetic acid and N-hydroxyethylethylenediaminetriacetic acid, which have good chelating ability for iron and high desulfurization efficiency. High; but the desulfurization operation cost is high and the sulfur capacity is low.

The iron chelating agent used in the SulFerox process developed by Shell Oil and Dow Chemical, and the Sulfint process developed by the Vienna Technical University and the Austrian United Engineering Company for the desulfurization liquid is EDTA, which is characterized by a small degree of degradation, Large chelation capacity increases the concentration of complexed iron in the desulfurization solution and reduces the amount of liquid circulation.

The DDS desulfurization process developed by the School of Chemistry and Molecular Engineering of Peking University uses porphyrin, heme, etc. as iron chelating agents in the desulfurization liquid. This method has high desulfurization efficiency, environmental protection and no pollution; but the stability of the desulfurization liquid is poor.

Contents of the invention

The invention aims to provide a complex iron desulfurizer, and also provides a method for using the desulfurizer, which is suitable for removing hydrogen sulfide gas under a supergravity field.

The invention provides a complex iron desulfurizer, which is composed of the following components: soluble iron salt, iron salt chelating agent, sulfide absorbent, stabilizer, composite sulfur particle sedimentation agent and multifunctional corrosion inhibitor; desulfurization The soluble iron salt in the agent contains Fe ³⁺ and Fe ²⁺ ; the molar ratio of the chelating agent to the iron salt is 1.2:1～3:1; the ratio of each component is as follows:

Soluble iron salt: 2.2 to 12 parts,

Iron salt chelating agent: 5-20 parts;

Sulfide absorbent: 15-70 parts;

Stabilizer: 0.1 to 15 parts;

Composite sulfur particle sedimentation agent: 0.05 to 2 parts;

Multifunctional corrosion inhibitor: 0.05 to 5 parts.

Further, the molar ratio of Fe ³⁺ to Fe ²⁺ in the soluble iron salt is 1:3-5:1, wherein FeNH ₄ (SO ₄ ) ₂ ·12H ₂ O or Fe ₂ provides Fe ³⁺ At least one of (SO ₄ ) ₃ , wherein Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ·6H ₂ O provides Fe ²⁺ .

Further, the chelating agent is EDTA, Na ₄ EDTA, NTA, Na ₃ NTA, HEDTA, Na ₃ HEDTA, DTPA, HEDP, TEA, citric acid, sodium citrate, sulfosalicylic acid, sulfosalicylic acid One or more of sodium sulfate and gluconic acid.

Further, the sulfide absorbent is one or more of NaOH, Na ₂ CO ₃ , NaHCO ₃ , KOH, K ₂ CO ₃ , KHCO ₃ .

Further, the stabilizer is one or more of imidazole, benzoate, alkali metal chloride, alkali metal thiosulfate.

Further, the composite sulfur particle settling agent is composed of a flocculation initiator, a flocculation coagulant, and a flocculation settling agent:

The flocculation initiator is one or two of sublimated sulfur and chitosan, and the content is 12% to 20% of the sulfur particle sedimentation agent;

The flocculation coagulant is one or two of AlCl ₃ and sodium silicate, the content of which is 3% to 32% of the sulfur particle settling agent;

The flocculation-settling agent is two or more of PAM, straight-chain decanol, polyethylene glycol ether, and straight-chain cetyl alcohol, and the content is 55% to 84% of the sulfur particle sedimentation agent.

Further, the multifunctional corrosion inhibitor is composed of a stable complex iron main corrosion inhibitor, a stable complex iron auxiliary corrosion inhibitor, a bactericidal corrosion inhibitor, and a stable potential corrosion inhibitor:

The main corrosion inhibitor is one or a mixture of alkali metal sulfate and tungstate, and the content is 27% to 57% of the multifunctional corrosion inhibitor;

The corrosion inhibitor is one or a mixture of alkali metal benzoate and silicate, and the content is 3% to 15% of the multifunctional corrosion inhibitor;

The bactericidal corrosion inhibitor is one or a mixture of two or more of potassium bromide, potassium iodide, and formaldehyde, and the content is 18% to 66% of the multifunctional corrosion inhibitor;

The stable potential corrosion inhibitor is one or both of sodium dodecylsulfonate and sodium p-toluenesulfonate, and the content is 3% to 11% of the multifunctional corrosion inhibitor.

The invention provides a method for using a complex iron desulfurizer, comprising the following steps:

(1) Pump the complex iron desulfurizer in the liquid storage tank into the desulfurization supergravity rotating packing bed at a flow rate of 20-80L/h, and contact with the gas flow rate of 2Nm ³ /h containing hydrogen sulfide gas in the packing of the drum in countercurrent contact , the hydrogen sulfide gas is absorbed by the alkaline solution in the desulfurizer and transformed into HS _- , oxidized by the Fe ³⁺ L in the desulfurizer to sulfur element, and the Fe ³⁺ L in the desulfurizer is reduced to Fe ²⁺ L;

(2) The gas after hydrogen sulfide removal is emptied through the built-in demister in the high-gravity rotary packed bed, and the complex iron desulfurization rich liquid is pumped into the regenerated high-gravity rotary packed bed at a flow rate of 20-80L/h to be rotated with the air. Countercurrent contact in the filling of the drum, the Fe ²⁺ L in the desulfurizer is re-oxidized to Fe ³⁺ L by the oxygen in the air, and the regeneration temperature is 40-50°C;

(3) The regenerated desulfurizer is pumped into the liquid storage tank, and the composite sulfur particle sedimentation agent is added to make the sulfur quickly flocculate and settle to the bottom of the liquid storage tank, and then pumped into the filter, and the formed sulfur cake is processed subsequently. The filtrate is returned to the liquid storage tank for the next cycle desulfurization process.

Further, the total iron concentration of soluble iron salts in the complex iron desulfurizer is 2.2-12g/L, wherein the molar ratio of Fe3 ⁺ to Fe2 ⁺ is 1:3-5:1; the concentration of chelating agent is 5-20g /L; sulfide absorbent concentration 15-70g/L; stabilizer concentration 0.1-15g/L; composite sulfur particle sedimentation agent concentration 0.05-2g/L; multifunctional corrosion inhibitor concentration 0.05-5g/L; chelating agent The molar ratio to iron salt is 1.2:1~3:1; the pH value of the solution is 8.0~9.5.

The principle of the present invention is that the complex iron desulfurizer uses alkaline solution to absorb hydrogen sulfide gas to generate HS _- in the absorption process, and oxidizes HS ^- to simple sulfur through Fe ³⁺ L, while Fe ³⁺ L is reduced to Fe ²⁺ L ; During the regeneration process, Fe ²⁺ L is re-oxidized to Fe ³⁺ L by the oxygen in the air, the desulfurizer is regenerated, and the hydrogen sulfide gas is recycled. Its main reaction is as follows:

(1) Absorption and oxidation of H ₂ S

H ₂ S(aq)→H ⁺ +HS ^-

HS ^- +2Fe ³⁺ L ^n- → 2Fe ²⁺ L ^n- +2H ⁺ +S↓

(2) Oxidative regeneration of Fe ²⁺

O ₂ (aq)+4Fe ²⁺ L ^n- +2H ₂ O→4Fe ³⁺ L ^n- +4OH ^-

Beneficial effects of the present invention:

The invention is a new process for removing hydrogen sulfide, which combines a novel complex iron desulfurizer with a high-gravity technology. The desulfurizer of this process has high desulfurization efficiency (hydrogen sulfide concentration is lower than 10ppm after a single absorption), high working sulfur capacity (up to 1.35g/L), and stable complex iron desulfurizer (total iron concentration can reach 12g/L) , sulfur particles are easy to settle (3 to 8 minutes, the particle size of the settled sulfur is concentrated at 140 to 177 microns); the supergravity technology of this process has high gas-liquid mass transfer efficiency, less liquid circulation, and a small footprint. The entire equipment can be skid-mounted . Thereby reducing equipment investment, reducing energy consumption, and giving full play to the significant advantages of the combination of new complex iron desulfurizer and high gravity technology.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

In the figure, 1 is a liquid storage tank, 2 is a desulfurization supergravity rotating packed bed, 3 is a regenerative supergravity rotating packed bed, 4 is a filter, 5 is a gas containing hydrogen sulfide, 6 is a purified gas, 7 is air, and 8 is an exhaust Air, 9 is solid sulfur.

Detailed ways

The present invention is further illustrated by the following examples, but not limited to the following examples.

First, examples of compound type sulfur particle sedimentants are as follows:

Example a: Sulfur particle sedimentation agent, composed of the following components: decyl alcohol 50mg/L, cetyl alcohol 40mg/L, PAM 4mg/L, chitosan 10mg/L, sublimated sulfur 10mg/L, sodium silicate 35mg/L ;

Example b: Sulfur particle sedimentation agent, consisting of the following components: decyl alcohol 24mg/L, cetyl alcohol 96mg/L, polyethylene glycol ether 30mg/L, sublimated sulfur 30mg/L, aluminum chloride 50mg/L;

Example c: Sulfur particle sedimentation agent, consisting of the following components: aluminum chloride 10mg/L, polyethylene glycol ether 50mg/L, chitosan 5mg/L, sublimated sulfur 10mg/L, PAM 10mg/L, sodium silicate 15mg/L;

Example d: Sulfur particle sedimentation agent, composed of the following components: decyl alcohol 96mg/L, cetyl alcohol 24mg/L, polyethylene glycol ether 80mg/L, PAM 4mg/L, chitosan 40mg/L, sublimated sulfur 10mg /L, sodium silicate 5mg/L, aluminum chloride 80mg/L;

Example e: Sulfur particle sedimentation agent, composed of the following components: decyl alcohol 60mg/L, cetyl alcohol 60mg/L, chitosan 10mg/L, sublimated sulfur 10mg/L, PAM 4mg/L, sodium silicate 5mg/L .

Second, examples of multifunctional corrosion inhibitors are as follows:

Example a: Sodium Benzoate 0.2g/L, Potassium Sulfate 1g/L, Sodium Tungstate 0.1g/L, Potassium Silicate 0.2g/L, Potassium Bromide 0.5g/L, Formaldehyde 1g/L, Dodecyl Sulfonate Sodium acid 0.2g/L

Example b: sodium benzoate 0.2g/L, sodium sulfate 1.6g/L, sodium tungstate 0.1g/L, potassium silicate 0.2g/L, potassium bromide 0.5g/L, formaldehyde 1g/L, dodecyl Sodium sulfonate 0.2g/L

Example c: sodium benzoate 1g/L, sodium sulfate 6g/L, sodium tungstate 0.3g/L, potassium silicate 1g/L, potassium bromide 2g/L, formaldehyde 3.5g/L, sodium p-toluenesulfonate 1g/L L

Example d: sodium benzoate 2g/L, potassium sulfate 8g/L, sodium tungstate 0.5g/L, potassium silicate 1g/L, potassium iodide 5g/L, formaldehyde 5g/L, sodium p-toluenesulfonate 2g/L

Embodiment 1: the preparation method of complex iron desulfurizer:

Ferric ammonium sulfate, ferrous ammonium sulfate, citric acid, and HEDTA were formulated into a solution with a total iron concentration of 2.2g/L according to a molar ratio of 3:1:1.2:3.6, and Na ₂ CO ₃ 19g/L was added to the solution L, sodium benzoate 1.3g/L, composite sulfur particle sedimentation agent example a: 0.15g/L, multifunctional corrosion inhibitor example b: 0.4g/L to make complex iron desulfurizer;

Embodiment 2: the preparation method of complex iron desulfurizer:

Ferric ammonium sulfate, ferric sulfate, ferrous ammonium sulfate, NTA, and HEDTA are formulated into a solution with a total iron concentration of 7g/L in a molar ratio of 3:2:1:6:1.2, and NaOH and NaOH are added to the solution. ₂ CO ₃ equal mass ratio mixture 35g/L, sodium benzoate and sodium thiosulfate equal mass ratio mixture 4.6g/L, composite sulfur particle sedimentation agent example c: 0.66g/L, multifunctional corrosion inhibitor example d : 1.3g/L made complex iron desulfurizer;

Embodiment 3: the preparation method of complex iron desulfurizer:

Ferric ammonium sulfate, ferric sulfate, ferrous ammonium sulfate, gluconic acid, and NTA are prepared into a solution with a total iron concentration of 12g/L according to a molar ratio of 2:1:1:1:3.6, and KOH and K ₂ CO ₃ equal mass ratio mixture 48g/L, imidazole 7.2g/L, compound sulfur particle sedimentation agent example e: 1.1g/L, multifunctional corrosion inhibitor example c: 3.4g/L to make complex iron desulfurizer;

Embodiment 4: the using method of complex iron desulfurizer

As shown in Figure 1: use novel complex iron desulfurizer of the present invention to remove hydrogen sulfide in the gas, pump the complex iron desulfurizer in liquid storage tank 1 into desulfurization supergravity rotary packed bed 2 and contain sulfide The hydrogen gas 5 is countercurrently contacted in the filler of the drum, the hydrogen sulfide-containing gas 5 is absorbed by the alkaline solution in the desulfurizer and converted into H2S ^- , oxidized by Fe ³⁺ L in the desulfurizer to simple sulfur, and the Fe in the desulfurizer ³⁺ L is reduced to Fe ²⁺ L; the purified gas 6 after removal of hydrogen sulfide is emptied through the built-in demister in the supergravity rotating packed bed, and the complex iron desulfurization rich liquid is pumped into the regenerated supergravity rotating packed bed 3 and The air 7 is in cross-flow or counter-current contact in the filler of the drum, and the Fe ²⁺ L in the desulfurizer is re-oxidized to Fe ³⁺ L by the oxygen in the air; the regenerated desulfurizer is pumped into the liquid storage tank 1, and added Composite sulfur particle settling agent can quickly flocculate and settle sulfur to the bottom of liquid storage tank 1, and then pump it into filter 4 to form sulfur cake for subsequent treatment, and the filtrate returns to liquid storage tank 1 for the next cycle desulfurization process.

(1) Experimental conditions

The experimental gas with a hydrogen sulfide concentration of 1300ppm was prepared from natural gas.

Experimental gas flow: 2Nm ³ /h

Experimental liquid flow: 20L/h

Absorption and regeneration temperature: 40～50℃

Solution pH: 8.5

(2) Desulfurization effect

Initial hydrogen sulfide concentration/ppm Purified gas hydrogen sulfide concentration/ppm Desulfurization rate/% Desulfurizer 1 1300 0.5 99.92 Desulfurizer 2 1300 0 100 Desulfurizer 3 1300 0 100

Embodiment 5: the using method of complex iron desulfurizer

Test method is the same as embodiment 4

(1) Experimental conditions

The experimental gas with a hydrogen sulfide concentration of 6000ppm was prepared from coking dry gas.

Experimental gas flow: 2Nm ³ /h

Experimental liquid flow: 60L/h

Absorption and regeneration temperature: 40～50℃

Solution pH: 8.5

(2) Desulfurization effect

Initial hydrogen sulfide concentration/ppm Purified gas hydrogen sulfide concentration/ppm Desulfurization rate/% Desulfurizer 1 6000 9 99.85 Desulfurizer 2 6000 5 99.92 Desulfurizer 3 6000 3 99.95

Embodiment 6: the using method of complex iron desulfurizer

Test method is the same as embodiment 4

(1) Experimental conditions

Prepare an experimental gas with a hydrogen sulfide concentration of 10000ppm with water gas.

Experimental gas flow: 2Nm ³ /h

Experimental liquid flow: 80L/h

Absorption and regeneration temperature: 40～50℃

Solution pH: 8.5

(2) Desulfurization effect

Initial hydrogen sulfide concentration/ppm Purified gas hydrogen sulfide concentration/ppm Desulfurization rate/% Desulfurizer 1 10000 10 99.90 Desulfurizer 2 10000 9 99.91 Desulfurizer 3 10000 5.5 99.95

Claims (5)

1. A complex iron desulfurizer, characterized in that: it is made up of the following components: soluble iron salt, iron salt chelating agent, sulfide absorbent, stabilizer, composite sulfur particle sedimentation agent and multifunctional corrosion inhibitor; The molar ratio of Fe ³⁺ to Fe ²⁺ contained in the soluble iron salt in the desulfurizer is 1:3~5:1; the molar ratio of the chelating agent to the iron salt is 1.2:1~3:1; the pH value of the solution is 8.0~ 9.5; the distribution ratio of each group is as follows: Soluble iron salt: 2.2~12 parts, Iron salt chelating agent: 5~20 parts; Sulfide absorbent: 15~70 parts; Stabilizer: 0.1~15 parts; Composite sulfur particle sedimentation agent: 0.05~2 parts; Multifunctional corrosion inhibitor: 0.05~5 parts; The soluble iron salt contains Fe ³⁺ and Fe ²⁺ , wherein Fe ³⁺ is provided by at least one of FeNH ₄ (SO ₄ ) ₂ ·12H ₂ O or Fe ₂ (SO ₄ ) ₃ , which provides Fe ²⁺ is Fe ₂ (NH ₄ ) ₂ (SO ₄ ) ₂ · 6H ₂ O; The chelating agent is EDTA, Na ₄ EDTA, NTA, Na ₃ NTA, HEDTA, Na ₃ HEDTA, DTPA, HEDP, TEA, citric acid, sodium citrate, sulfosalicylic acid, sodium sulfosalicylate, One or several kinds of gluconic acid; The composite sulfur particle settling agent is composed of a flocculation initiator, a flocculation coagulant, and a flocculation settling agent: The flocculation initiator is one or both of sublimated sulfur and chitosan, and the content is 12% to 20% of the sulfur particle sedimentation agent; The flocculation coagulant is one or two of AlCl ₃ and sodium silicate, the content of which is 3% to 32% of the sulfur particle sedimentation agent; The flocculation-settling agent is two or more of PAM, straight-chain decanol, polyethylene glycol ether, and straight-chain cetyl alcohol, and the content is 55% to 84% of the sulfur particle sedimentation agent. 2. The complex iron desulfurizer according to claim 1, characterized in that: the sulfide absorbent is one of NaOH, Na ₂ CO ₃ , NaHCO ₃ , KOH, K ₂ CO ₃ , KHCO ₃ or several. 3. complex iron desulfurizer according to claim 1, is characterized in that: described stabilizing agent is one or more in imidazole, benzoate, alkali metal chloride salt, alkali metal thiosulfate kind. 4. The complexed iron desulfurizer according to claim 1, characterized in that: the multifunctional corrosion inhibitor consists of a stable complexed iron main corrosion inhibitor, a stable complexed iron auxiliary corrosion inhibitor, a bactericidal type corrosion inhibitor Agent, stable potential corrosion inhibitor composition: The main corrosion inhibitor is one or a mixture of two or more of alkali metal sulfate and tungstate, and the content is 27% to 57% of the multifunctional corrosion inhibitor; The corrosion inhibitor is one or a mixture of two or more of alkali metal benzoate and silicate, and the content is 3% to 15% of the multifunctional corrosion inhibitor; The bactericidal corrosion inhibitor is one or more mixtures of potassium bromide, potassium iodide and formaldehyde, and the content is 18% to 66% of the multifunctional corrosion inhibitor; The stable potential corrosion inhibitor is one or both of sodium dodecylsulfonate and sodium p-toluenesulfonate, and the content is 3% to 11% of the multifunctional corrosion inhibitor. 5. a method for using the complex iron desulfurizer described in any one of claims 1 to 4, characterized in that: comprising the following steps: (1) Pump the complexed iron desulfurizer in the liquid storage tank into the desulfurization supergravity rotating packing bed at a flow rate of 20~80L/h, and contact with the gas flow rate of 2Nm ³ /h containing hydrogen sulfide in the packing of the drum in countercurrent , the hydrogen sulfide gas is absorbed by the alkaline solution in the desulfurizer and transformed into HS ^- , oxidized by Fe ³⁺ L in the desulfurizer to simple sulfur, and the Fe ³⁺ L in the desulfurizer is reduced to Fe ²⁺ L, the absorption temperature 40~50℃; (2) The gas after hydrogen sulfide removal is emptied through the built-in demister in the high-gravity rotary packed bed, and the complex iron desulfurization rich liquid is pumped into the regenerated high-gravity rotary packed bed at a flow rate of 20~80L/h, and the air is rotated Countercurrent contact in the filling of the drum, the Fe ²⁺ L in the desulfurizer is re-oxidized to Fe ³⁺ L by the oxygen in the air, and the regeneration temperature is 40~50°C; (3) The regenerated desulfurizer is pumped into the liquid storage tank, and the composite sulfur particle sedimentation agent is added to make the sulfur quickly flocculate and settle to the bottom of the liquid storage tank, and then pumped into the filter, and the formed sulfur cake is processed subsequently. The filtrate is returned to the liquid storage tank for the next cycle desulfurization process.