CN111232920B - Method for producing hydrogen by coke oven coal chemical looping - Google Patents

Abstract

The invention relates to a method for preparing hydrogen by coke oven coal chemical looping, belonging to the technical field of energy chemical industry. The invention uses oxygen carrier Ce _1‑x Fe _x O _2‑δ Ce-Fe-X-O (X = Mn, cu or Ni), niO/MgO, la _1‑x Sr _x FeO ₃ 、LaNi _x Fe _1‑x O ₃ Respectively react with the coke oven gas to convert the coke oven gas into CO in a reduction stage ₂ And water or synthetic gas, and water vapor is introduced in the oxidation stage to generate pure hydrogen. The gas (hydrogen, methane and carbon monoxide) in the coke oven gas is fully utilized, the purity of the generated hydrogen is as high as 99.0 percent, the oxygen carrier can be recycled, and the economic and efficient utilization of the oxygen carrier and the coke oven gas is realized.

Description

A method for coke oven gas chemical chain hydrogen production

technical field

The invention relates to a method for coke oven gas chemical chain hydrogen production, which belongs to the technical field of energy and chemical industry.

Background technique

Coke oven gas is a by-product of the coking process, mainly including _H2 (55-60vol%), CO (5-8vol%), _CO2 (3-6vol%), _CH4 (23-27vol%) and some impurities (such as N ₂ and H ₂ S), the ignition point is 600～650℃, and the calorific value is about 17580KJ/m ³ ～18420KJ/m ³ . At present, the utilization of coke oven gas is limited and is still at a very low level, usually only 20-50% of coke oven gas is used as fuel, and most of the remaining coke oven gas is burned by torches, or even discharged directly in some cases into the air, resulting in a huge waste of energy and serious environmental pollution.

Due to the high content of hydrogen and methane in coke oven gas, direct use of coke oven gas as fuel cannot make full and efficient use of coke oven gas, and also produces greenhouse gas CO ₂ . In recent years, coke oven gas has been regarded as a potential low-cost raw material for hydrogen production. At present, the main methods for hydrogen production from coke oven gas are pressure swing adsorption and membrane separation. However, these two methods do not use coke. There are other gases in the coke oven gas except hydrogen, namely CH ₄ , CO and CO ₂ , so the overall utilization efficiency of coke oven gas needs to be improved.

Contents of the invention

The present invention aims at the resource utilization problem of coke oven gas existing in the prior art, and provides a coke oven gas chemical chain hydrogen production method. The present invention is based on Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ , LaNi _x Fe _1-x O ₃ oxygen carrier adopts chemical chain method to efficiently utilize each component of coke oven gas to produce Pure hydrogen, Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ , LaNi _x Fe _1-x O ₃ Such oxygen carriers can be recycled repeatedly, which greatly saves costs, and economically and efficiently utilizes oxygen carriers and coke oven gas. The invention effectively overcomes the shortcomings and deficiencies of traditional coke oven gas component separation and hydrogen production.

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put the oxygen carrier in the reaction tube and raise the temperature to 750~900℃ at a constant speed, where the oxygen carrier is Ce _1-x Fe _x O _2-δ , Ce-Fe-XO, NiO/MgO, La _1-x Sr _x One or more of FeO ₃ , LaNi _x Fe _1-x O ₃ oxygen carriers, X in Ce-Fe-XO is Mn, Cu or Ni;

(2) Pass the coke oven gas into the reaction tube in step (1), and the coke oven gas reacts with the oxygen carrier at a temperature of 750-900°C, the oxygen carrier is reduced to an oxygen-deficient carrier, and the coke oven gas is oxidized to CO ₂ Mixtures with water or synthesis gas;

(3) Pass water vapor into the reaction tube of step (2), and react with the oxygen-depleted carrier at a temperature of 750-900°C, the oxygen-depleted carrier is oxidized by water vapor The carrier deprives oxygen and becomes hydrogen;

(4) Condensing and separating the excess water vapor and hydrogen gas mixture in step (3), and purifying to obtain pure H ₂ .

In the step (1) 0<x<1 in Ce _1-x Fe _x O _2-δ , the molar ratio of Ce, Fe and X in Ce-Fe-XO is 6:2:2, NiO/MgO, La ₁ 0<x<1 in _-x Sr _x FeO ₃ , 0<x<0.1 in LaNi _x Fe _1-x O ₃ .

The main components of the coke oven gas in the step (2) are H ₂ , CH ₄ , CO and CO ₂ , and the flow rate of the coke oven gas is 100-200 mL/min.

Further, the preparation method of the oxygen carrier is

1) Dissolving the oxygen carrier metal precursor salt in deionized water to obtain an oxygen carrier precursor salt mixed solution;

2) Stir the mixed solution of oxygen carrier precursor salt in step 1) in a water bath with a temperature of 20-70°C, and at the same time, drop ammonia water into the mixed solution of oxygen carrier precursor salt to adjust the pH value of the system to 9-10, and continue Stir the reaction for 0.5-3 hours, then let it stand for aging for 1-6 hours, separate the solid from the liquid, and wash the solid 2-5 times alternately with deionized water-absolute ethanol;

3) The solid washed in step 2) is dried, crushed, and then placed in an air atmosphere at a temperature of 750-850° C. for 2-6 hours to obtain an oxygen carrier.

In the step 1) the concentration of the oxygen carrier precursor salt mixed solution is 0.1-0.3 mol/L.

Said step 2) the mass concentration of ammonia water is 5%-25%, and the titration rate is 1-5 drops/s.

The value of _δ in the Ce _{1-x Fex} O _2-δ is far less than 2, reaching a negligible level.

Coke oven gas is the gas after complete pretreatment such as tar removal, desulfurization, naphthalene removal, ammonia washing, light oil removal, recovery of benzene, toluene, xylene, etc. The main components are H ₂ , CH ₄ , CO and CO ₂ .

Only one oxygen carrier needs to be loaded into the reaction tube of the present invention, coke oven gas and Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _{1- x} Sr _x FeO ₃ or LaNi _x Fe _1-x O ₃ oxygen carrier reacts to produce CO ₂ and water or synthesis gas. At this time, the oxygen carrier is reduced, and then water vapor is introduced to react with the reduced oxygen-depleted carrier to generate hydrogen , the reduced oxygen-depleted carrier is also oxidized by water vapor to return to the initial state of the oxygen carrier; the present invention Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ , LaNi _x Fe _1-x O ₃ oxygen carriers can promote the partial oxidation of methane in coke oven gas to syngas or complete oxidation to CO ₂ and H ₂ O in different degrees, and Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ , LaNi _x Fe _1-x O ₃ oxygen carriers can be recycle. During the reaction process, the synthesis gas obtained from coke oven gas conversion in the reduction stage can be used as chemical raw materials. If the coke oven gas is completely converted into CO ₂ and H ₂ O in the reduction stage, CO ₂ can be better captured to reduce CO ₂ emissions. The high-purity hydrogen obtained in the oxidation stage can be used as fuel or chemical raw material, etc., and it can also be used to smelt important metals by utilizing the reducing property of hydrogen.

The beneficial effects of the present invention are:

(1) The present invention effectively overcomes the _shortcomings and _deficiencies of traditional coke oven gas component separation and hydrogen _production . Ni), NiO/MgO, La _1-x Sr _x FeO ₃ or LaNi _x Fe _1-x O ₃ oxygen carrier using chemical chain method to efficiently utilize each component of coke oven gas to produce pure hydrogen;

(2) Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ or LaNi _x Fe _1-x O ₃ Oxygen carriers can promote the partial oxidation of methane in coke oven gas to syngas or complete oxidation to CO ₂ and H ₂ O to varying degrees, and Ce _1-x Fe _x O _2-δ , Ce-Fe-XO (X=Mn, Cu or Ni), NiO/MgO, La _1-x Sr _x FeO ₃ or LaNi _x Fe _1-x O ₃ oxygen carriers can also be recycled repeatedly, which greatly saves costs and economically and efficiently utilizes oxygen carriers and coke ovens gas.

Description of drawings

Fig. 1 is the change figure of each component of coke oven gas reaction of embodiment 1;

Fig. 2 is embodiment 1 steam hydrogen production curve figure;

Fig. 3 is the change figure of each component of coke oven gas reaction of embodiment 2;

Fig. 4 is embodiment 2 steam hydrogen production curve figure;

Fig. 5 is the change figure of each component of coke oven gas reaction of embodiment 3;

Fig. 6 is embodiment 3 steam hydrogen production curve figure;

Fig. 7 is the change figure of each component of coke oven gas reaction of embodiment 4;

Fig. 8 is embodiment 4 steam hydrogen production curve figure;

Fig. 9 is the change figure of each component of coke oven gas reaction of embodiment 5;

Fig. 10 is a curve diagram of hydrogen production by water vapor in Example 5.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the content described.

Example 1: The preparation method of Ce ₆ Fe ₄ O _2-δ oxygen carrier, the specific steps are as follows:

1) Dissolve Ce(NO ₃ ) ₃ .6H ₂ O and Fe(NO ₃ ) ₃ .9H ₂ O in deionized water to obtain a mixed solution of oxygen carrier precursor salt; wherein Ce(NO ₃ ) ₃ .6H ₂ O, Fe The molar ratio of (NO ₃ ) ₃ .9H ₂ O is 6:4, and the total concentration of the oxygen carrier precursor salt mixed solution is 0.25mol/L;

2) Stir the oxygen carrier precursor salt mixed solution in step 1) in a water bath at a temperature of 70°C, and at the same time, drop ammonia water with a mass concentration of 15% into the oxygen carrier precursor salt mixed solution at a rate of 1 drop/s Adjust the pH value of the system to 9.5, continue to stir and react for 3 hours, then let it stand for aging for 3 hours, separate the solid from the liquid, and wash the solid 4 times alternately with deionized water-absolute ethanol;

3) Dry the solid washed in step 2) at a temperature of 110°C for 12 hours, then pulverize it and place it in an air atmosphere at a temperature of 750°C for 2 hours to obtain Ce ₆ Fe ₄ O _2-δ oxygen carrier, wherein the calcined The heating rate is 10°C/min, and the prepared Ce ₆ Fe ₄ O _2-δ oxygen carrier is granulated into 20-40 mesh for coke oven gas chemical chain hydrogen production;

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put 2g of Ce ₆ Fe ₄ O _2-δ oxygen carrier in the reaction tube and raise the temperature to 850°C at a constant speed;

(2) Pass the coke oven gas into the reaction tube in step (1), and the coke oven gas reacts with the Ce ₆ Fe ₄ O _2-δ oxygen carrier at a temperature of 850°C, and the Ce ₆ Fe ₄ O _2-δ oxygen carrier is Reduced to an oxygen-depleted carrier, the coke oven gas is oxidized into a mixture of CO ₂ and water or synthesis gas; the coke oven gas is a fully pretreated gas, and the composition and volume content of the coke oven gas are: H ₂ (6.0%), CH ₄ (2.8%), CO (0.9%), CO ₂ (0.3%); coke oven gas flow rate is 120mL/min;

(3) Pass water vapor into the reaction tube of step (2), wherein the flow rate of water vapor is 150mL/min, and react with the oxygen-depleted carrier at a temperature of 850°C, and the oxygen-depleted carrier is oxidized to Ce ₆ Fe ₄ O _2-δ oxygen carrier, water vapor becomes hydrogen due to deprivation of oxygen by oxygen carrier;

(4) condensing and separating the redundant water vapor and the mixed gas of hydrogen in step (3), and purifying to obtain pure H ₂ ;

See Figure 1 for the change diagram of each component of coke oven gas reaction in this example, and Figure 2 for the hydrogen production curve of water vapor; from Figure 1 and Figure 2, it can be seen that when coke oven gas reacts with oxygen carrier, the overall conversion rate of _CH4 is low , in the early stage of the reaction, CH ₄ and CO are converted into CO ₂ , and H ₂ is converted into water (the peak of water cannot be detected by mass spectrometry), resulting in an increase in the content of CO ₂ , and a large amount of synthesis gas is produced in the late stage of the reaction, so H ₂ and The overall content of CO increased; the time of passing water vapor to generate _H2 was 20 minutes, and almost no CO was produced, indicating that the purity of hydrogen was very high; the coke oven gas and oxygen carrier were reacted alternately, and then the reduced oxygen carrier was oxidized by passing water steam to produce Hydrogen can realize the recycling of oxygen carrier.

Embodiment 2: Ce-Fe-Mn-O oxygen carrier preparation method, the specific steps are as follows:

1) Dissolve Ce(NO ₃ ) ₃ .6H ₂ O, Fe(NO ₃ ) ₃ .9H ₂ O, MnN ₂ O ₆ .4H ₂ O in deionized water to obtain a mixed solution of oxygen carrier precursor salt; ₃ ) The molar ratio of ₃ .6H ₂ O, Fe(NO ₃ ) ₃ .9H ₂ O, MnN ₂ O ₆ .4H ₂ O is 6:2:2, and the concentration of the oxygen carrier precursor salt mixture solution is 0.1mol/L;

2) Stir the mixed solution of oxygen carrier precursor salt in step 1) in a water bath at a temperature of 20°C, and drop ammonia water with a mass concentration of 5% into the mixed solution of oxygen carrier precursor salt at a rate of 2 drops/s to adjust The pH value of the system was 9.0, and the reaction was continuously and rapidly stirred for 1 hour, then left to age for 6 hours, separated from the solid and liquid, and washed twice alternately with deionized water-absolute ethanol;

3) Dry the solid washed in step 2) at a temperature of 80°C for 6 hours, then pulverize it and then calcinate it in an air atmosphere at a temperature of 800°C for 4 hours to obtain the Ce-Fe-Mn-O oxygen carrier. The speed is 5°C/min, and the prepared Ce-Fe-Mn-O oxygen carrier is granulated into 20-40 mesh for coke oven gas chemical chain hydrogen production;

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put 0.5g Ce-Fe-Mn-O oxygen carrier in the reaction tube and raise the temperature to 800°C at a constant speed;

(2) The coke oven gas is passed into the reaction tube in step (1), and the coke oven gas reacts with the Ce-Fe-Mn-O oxygen carrier at a temperature of 800 ° C, and the Ce-Fe-Mn-O oxygen carrier is reduced to Oxygen loss carrier, coke oven gas is oxidized into a mixture of CO ₂ and water or synthesis gas; among them, coke oven gas is a fully pretreated gas, and the composition and volume content of coke oven gas are: H ₂ (6.0%), CH ₄ (2.8%), CO (0.9%), CO ₂ (0.3%); coke oven gas flow rate is 100mL/min;

(3) Pass water vapor into the reaction tube of step (2), wherein the water vapor flow rate is 150mL/min, and react with the oxygen-depleted carrier at a temperature of 800°C, and the oxygen-depleted carrier is oxidized to Ce-Fe-Mn -O oxygen carrier, water vapor becomes hydrogen due to deprivation of oxygen by the oxygen carrier;

(4) condensing and separating the redundant water vapor and the mixed gas of hydrogen in step (3), and purifying to obtain pure H ₂ ;

See Figure 3 for the change diagram of each component of the coke oven gas reaction in this example, and Figure 4 for the hydrogen production curve of water vapor; it can be seen from Figure 3 and Figure 4 that when the coke oven gas reacts with the oxygen carrier, the overall conversion rate of _CH4 is low , in the early stage of the reaction, CH ₄ and CO are converted into CO ₂ , and H ₂ is converted into water (the peak of water cannot be detected by mass spectrometry), resulting in an increase in the content of CO ₂ , and a small amount of synthesis gas is produced in the late stage of the reaction, and the consumption of H ₂ is greater than the generated synthesis gas, so the overall content of _H2 is reduced; the time for generating _H2 by passing water steam is 25 minutes, and almost no CO is produced, indicating that the purity of hydrogen is very high; alternately react coke oven gas and oxygen carrier, and then pass water steam By oxidizing the reduced oxygen carrier to produce hydrogen, the oxygen carrier can be recycled.

Embodiment 3: NiO/MgO oxygen carrier preparation method, specific steps are as follows:

1) Dissolve Ni(NO ₃ ) ₂ .6H ₂ O and Mg(NO ₃ ) ₂ .6H ₂ O in deionized water to obtain a mixed solution of oxygen carrier precursor salt; wherein Ni(NO ₃ ) ₂ .6H ₂ O, Mg The molar ratio of (NO ₃ ) ₂ .6H ₂ O is 1:1, and the concentration of the oxygen carrier precursor salt mixture solution is 0.2mol/L;

2) Stir the mixed solution of oxygen carrier precursor salt in step 1) in a water bath at a temperature of 50°C, and drop ammonia water with a mass concentration of 20% into the mixed solution of oxygen carrier precursor salt at a rate of 3 drops/s to adjust The pH value of the system was 9.3, and the reaction was continuously and rapidly stirred for 1 hour, then left to age for 4 hours, separated from the solid and liquid, and washed twice alternately with deionized water-absolute ethanol;

3) Dry the washed solid in step 2) at a temperature of 100°C for 18 hours, then pulverize it and place it in an air atmosphere at a temperature of 800°C for 4 hours to obtain the NiO/MgO oxygen carrier, wherein the heating rate of the calcination is 5°C /min, the prepared NiO/MgO oxygen carrier is granulated into 20-40 mesh for coke oven gas chemical chain hydrogen production;

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put 1.0g NiO/MgO oxygen carrier in the reaction tube and raise the temperature to 850°C at a constant speed;

(2) Pass the coke oven gas into the reaction tube in step (1), and the coke oven gas reacts with the NiO/MgO oxygen carrier at a temperature of 850° C. Oxidation into a mixture of CO ₂ and water or synthesis gas; among them, coke oven gas is a fully pretreated gas, and the composition and volume content of coke oven gas are: H ₂ (6.0%), CH ₄ (2.8%), CO (0.9 %), CO ₂ (0.3%); coke oven gas flow rate is 150mL/min;

(3) Pass water vapor into the reaction tube of step (2), wherein the water vapor flow rate is 150mL/min, and react with the oxygen-depleted carrier at a temperature of 850°C, and the oxygen-depleted carrier is oxidized to NiO/MgO oxygen carrier , water vapor becomes hydrogen due to deprivation of oxygen by the oxygen-deprived carrier;

(4) condensing and separating the redundant water vapor and the mixed gas of hydrogen in step (3), and purifying to obtain pure H ₂ ;

See Figure 5 for the variation diagram of each component of the coke oven gas reaction in this example, and Figure 6 for the hydrogen production curve of water vapor; it can be seen from Figure 5 and Figure 6 that when the coke oven gas reacts with the oxygen carrier, the overall conversion rate of _CH4 is relatively high , but the content of H ₂ generated by passing water steam in the second step is very low, indicating that the NiO/MgO oxygen carrier is not suitable for hydrogen production from coke oven gas.

Example 4: La _0.5 Sr _0.5 FeO ₃ oxygen carrier preparation method, the specific steps are as follows:

1) Dissolve La(NO ₃ ) ₃ .6H ₂ O, Sr(NO ₃ ) ₂ , Fe(NO ₃ ) ₃ .9H ₂ O in deionized water to obtain a mixed solution of oxygen carrier precursor salt; where La(NO ₃ ) The molar ratio of _{3.6H 2} O, Sr(NO ₃ ) ₂ , Fe(NO ₃ ) ₃ .9H ₂ O is 0.5:0.5:1, and the concentration of the oxygen carrier precursor salt mixture solution is 0.3mol/L;

2) Stir the mixed solution of oxygen carrier precursor salt in step 1) in a water bath at a temperature of 60°C, and drop ammonia water with a mass concentration of 10% into the mixed solution of oxygen carrier precursor salt at a rate of 5 drops/s to adjust The pH value of the system was 9.7, and the reaction was continuously and rapidly stirred for 2 hours, then left to age for 6 hours, separated from the solid and liquid, and then the solid was washed 4 times alternately with deionized water-absolute ethanol;

3) Dry the solid washed in step 2) at a temperature of 90°C for 24 hours, then crush it and place it in an air atmosphere at a temperature of 850°C for 6 hours to obtain the La _0.5 Sr _0.5 FeO ₃ oxygen carrier. The temperature is 7°C/min, and the prepared La _0.5 Sr _0.5 FeO ₃ oxygen carrier is granulated into 20-40 mesh for coke oven gas chemical loop hydrogen production;

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put 1.5g La _0.5 Sr _0.5 FeO ₃ oxygen carrier in the reaction tube and raise the temperature to 900°C at a constant speed;

(2) Pass the coke oven gas into the reaction tube in step (1), and the coke oven gas reacts with the La _0.5 Sr _0.5 FeO ₃ oxygen carrier at a temperature of 900 ° C, and the La _0.5 Sr _0.5 FeO ₃ oxygen carrier is reduced to the deoxygenated Carrier, coke oven gas is oxidized into a mixture of CO ₂ and water or synthesis gas; among them, coke oven gas is a fully pretreated gas, and the composition and volume content of coke oven gas are: H ₂ (6.0%), CH ₄ (2.8 %), CO (0.9%), CO ₂ (0.3%); coke oven gas flow rate is 200mL/min;

(3) Pass water vapor into the reaction tube of step (2), wherein the water vapor flow rate is 150mL/min, and react with the oxygen-depleted carrier at a temperature of 900°C, and the oxygen-depleted carrier is oxidized to La _0.5 Sr _0.5 FeO ₃ Oxygen carrier, water vapor becomes hydrogen due to deprivation of oxygen by the oxygen carrier;

(4) condensing and separating the redundant water vapor and the mixed gas of hydrogen in step (3), and purifying to obtain pure H ₂ ;

See Figure 7 for the variation diagram of each component of coke oven gas reaction in this example, and Figure 8 for the hydrogen production curve of water vapor; from Figure 7 and Figure 8, it can be seen that when coke oven gas reacts with oxygen carrier, the overall conversion rate of _CH4 is relatively high , in the early stage of the reaction, CH ₄ and CO are converted into CO ₂ , and H ₂ is converted into water (the peak of water cannot be detected by mass spectrometry), resulting in an increase in the content of CO ₂ , and a small amount of synthesis gas is produced in the late stage of the reaction, and the consumption of H ₂ is greater than the generated synthesis gas, so the overall content of _H2 decreases; the time for passing water steam to generate _H2 is 60 minutes, and a small amount of CO is detected, indicating that a small amount of methane cracked in the first step when it reacted with coke oven gas. lead to carbon deposition. The purity of hydrogen is also high; the reaction between coke oven gas and oxygen carrier is carried out alternately, and then the reduced oxygen-depleted carrier is oxidized by water vapor to produce hydrogen, so that the oxygen carrier can be recycled.

Embodiment 5: LaNi _0.07 Fe _0.93 O ₃ oxygen carrier preparation method, the specific steps are as follows:

1) Dissolve La(NO ₃ ) ₃ .6H ₂ O, Ni(NO ₃ ) ₂ .6H ₂ O, Fe(NO ₃ ) ₃ .9H ₂ O in deionized water to obtain a mixed solution of oxygen carrier precursor salt; where La The molar ratio of (NO ₃ ) ₃ .6H ₂ O, Ni(NO ₃ ) ₂ .6H ₂ O, Fe(NO ₃ ) ₃ .9H ₂ O is 1:0.07:0.93, and the concentration of the oxygen carrier precursor salt mixture solution is 0.25 mol/L;

2) Stir the mixed solution of oxygen carrier precursor salt in step 1) in a water bath at a temperature of 70°C, and drop ammonia water with a mass concentration of 25% into the mixed solution of oxygen carrier precursor salt at a rate of 5 drops/s to adjust The pH value of the system is 10, and the reaction is continuously stirred for 3 hours, then left to age for 6 hours, separated from the solid and liquid, and then the solid is washed 4 times alternately with deionized water-absolute ethanol;

3) Dry the solid washed in step 2) at a temperature of 120°C for 24 hours, then crush it and place it in an air atmosphere at a temperature of 800°C for 6 hours to obtain the LaNi _0.07 Fe _0.93 O ₃ oxygen carrier. The temperature is 10°C/min, and the prepared LaNi _0.07 Fe _0.93 O ₃ oxygen carrier is granulated into 20-40 mesh for coke oven gas chemical loop hydrogen production;

A method for coke oven gas chemical chain hydrogen production, the specific steps are as follows:

(1) Put 2.0g LaNi _0.07 Fe _0.93 O ₃ oxygen carrier in the reaction tube and raise the temperature to 800°C at a constant speed;

(2) Pass the coke oven gas into the reaction tube in step (1), and react the coke oven gas with the LaNi _0.07 Fe _0.93 O ₃ oxygen carrier at a temperature of 800 ° C, and the LaNi _0.07 Fe _0.93 O ₃ oxygen carrier is reduced to an oxygen-deficient Carrier, coke oven gas is oxidized into a mixture of CO ₂ and water or synthesis gas; among them, coke oven gas is a fully pretreated gas, and the composition and volume content of coke oven gas are: H ₂ (6.0%), CH ₄ (2.8 %), CO (0.9%), CO ₂ (0.3%); coke oven gas flow rate is 200mL/min;

(3) Pass water vapor into the reaction tube of step (2), wherein the water vapor flow rate is 150mL/min, and react with the oxygen-depleted carrier at a temperature of 800°C, and the oxygen-depleted carrier is oxidized to LaNi _0.07 Fe _0.93 O ₃ Oxygen carrier, water vapor becomes hydrogen due to deprivation of oxygen by the oxygen carrier;

(4) condensing and separating the redundant water vapor and the mixed gas of hydrogen in step (3), and purifying to obtain pure H ₂ ;

See Figure 9 for the change diagram of each component of coke oven gas reaction in this example, and Figure 10 for the hydrogen production curve of water vapor; from Figure 9 and Figure 10, it can be seen that when coke oven gas reacts with oxygen carrier, CH _is almost completely converted into High H ₂ /CO synthesis gas; the time to generate H ₂ by passing water steam is 50 minutes, and almost no CO is produced, indicating that the purity of hydrogen is very high; alternately react coke oven gas and oxygen carrier, and then pass water steam to oxidize and reduce The depleted oxygen carrier produces hydrogen, which can realize the recycling of the oxygen carrier.

Claims (5)

1. A method for coke oven gas chemical chain hydrogen production, characterized in that, the specific steps are as follows: (1) Put the oxygen carrier in the reaction tube and raise the temperature to 750~900°C at a constant speed, where the oxygen carrier is Ce _1-x Fe _x O _2-δ , Ce-Fe-XO, La _1-x Sr _x FeO ₃ , LaNi One or more of _x Fe _1-x O ₃ oxygen carriers, X in Ce-Fe-XO is Mn, Cu or Ni; 0<x<1 in Ce _1-x Fe _x O _2-δ , Ce-Fe - The molar ratio of Ce, Fe and X in XO is 6:2:2, 0<x<1 in La _1-x Sr _x FeO ₃ , 0<x<0.1 in LaNi _x Fe _1-x O ₃ ; (2) Pass the coke oven gas into the reaction tube in step (1), and the coke oven gas reacts with the oxygen carrier at a temperature of 750~900°C, the oxygen carrier is reduced to an oxygen-deficient carrier, and the coke oven gas is oxidized to CO in the early stage ₂ and water mixture, later oxidized into syngas; (3) Water vapor is then introduced into the reaction tube of step (2), and reacts with the oxygen-depleted carrier at a temperature of 750~900°C. The oxygen-depleted carrier is oxidized by water vapor The carrier deprives oxygen and becomes hydrogen; (4) Condensate and separate the excess water vapor and hydrogen mixture in step (3), and purify to obtain pure H ₂ . 2. The method for coke oven gas chemical chain hydrogen production according to claim 1, characterized in that: in step (2), the main components of coke oven gas are H ₂ , CH ₄ , CO and CO ₂ , and the flow rate of coke oven gas is 100~200mL/min. 3. according to the method for the coke oven gas chemical chain hydrogen production described in claim 1, it is characterized in that: the preparation method of oxygen carrier is 1) Dissolving oxygen carrier metal precursor salt in deionized water to obtain a mixed solution of oxygen carrier precursor salt; 2) Stir the oxygen carrier precursor salt mixed solution in step 1) in a water bath at a temperature of 20-70°C, and at the same time, drop ammonia water into the oxygen carrier precursor salt mixed solution drop by drop to adjust the pH of the system to 9~10, continue Stir the reaction for 0.5~3h, then let it stand for aging for 1~6h, separate the solid from the liquid, and wash the solid 2~5 times alternately with deionized water-absolute ethanol; 3) The solid washed in step 2) is dried, crushed, and then roasted in an air atmosphere at a temperature of 750-850°C for 2-6 hours to obtain an oxygen carrier. 4. The method for coke oven gas chemical chain hydrogen production according to claim 3, characterized in that: step 1) the total concentration of the oxygen carrier precursor salt mixed solution is 0.1-0.3 mol/L. 5. The method for coke oven gas chemical chain hydrogen production according to claim 3, characterized in that: step 2) the mass concentration of ammonia water is 5%-25%, and the titration rate is 1-5 drops/s.

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