阅读说明：本技术 一种木质素黑液吸附增强重整制氢的方法 (Method for producing hydrogen by adsorption and enhancement of lignin black liquor through reforming ) 是由 余皓 李函珂 吴世杰 党成雄 彭峰 王红娟 于 2019-09-25 设计创作，主要内容包括：本发明公开了一种木质素黑液吸附增强重整制氢的方法。该方法包括以下步骤：(1)于反应器中装填Ni-Ca-Al粉末催化剂；(2)以惰性气体作为载气,将木质素黑液水溶液注入反应器中进行重整制氢；(3)当CO<Sub>2</Sub>的吸附达到饱和后,于惰性气氛中进行催化剂再生。所述Ni-Ca-Al催化剂是Ni、CaO和Ca<Sub>12</Sub>Al<Sub>14</Sub>O<Sub>33</Sub>的混合物。本发明可制得纯度高达96%的高纯氢气,氢气产率可达0.9 mol H<Sub>2</Sub>/mol C。Ni-Ca-Al催化剂在循环过程中表现出较好的稳定性。(The invention discloses a method for producing hydrogen by adsorption-enhanced reforming of lignin black liquor. The method comprises the following steps: (1) filling a Ni-Ca-Al powder catalyst in a reactor; (2) injecting lignin black liquor aqueous solution into a reactor by taking inert gas as carrier gas to carry out reforming hydrogen production; (3) when CO is present 2 After the adsorption of (a) is saturated, the catalyst is regenerated in an inert atmosphere. The Ni-Ca-Al catalyst is Ni, CaO and Ca 12 Al 14 O 33 A mixture of (a). The invention can prepare high-purity hydrogen with the purity of 96 percent and the hydrogen yield of 0.9mol H 2 Per mol of C. The Ni-Ca-Al catalyst shows better stability in the circulating process.)

1. A method for producing hydrogen by adsorption-enhanced reforming of lignin black liquor is characterized by comprising the following steps:

(1) Filling a Ni-Ca-Al powder catalyst in a reactor;

(2) Injecting lignin black liquor aqueous solution into a reactor by taking inert gas as carrier gas to carry out reforming hydrogen production;

(3) When CO is present₂After the adsorption of (a) is saturated, the catalyst is regenerated in an inert atmosphere.

2. The method according to claim 1, wherein in the step (1), the Ni-Ca-Al catalyst is Ni, CaO and Ca₁₂Al₁₄O₃₃A mixture of (a).

3. The method according to claim 1, wherein the mass content of Ni in the Ni-Ca-Al catalyst in the step (1) is 5-20%.

4. The method according to claim 1, wherein the molar ratio of Ca to Al in the Ni-Ca-Al catalyst in the step (1) is 1.6-3.4: 1.

5. the method according to claim 1, wherein the gas hourly space velocity of the lignin black liquor in the step (2) is 2000 ~ 9000h^-1 。

6. the method according to claim 1, wherein the concentration of the lignin black liquor aqueous solution in the step (2) is 0.104 ~ 0.313 g/ml.

7. The method according to claim 1, wherein the reaction temperature in the step (2) is 400 to 700 ℃.

8. the method of claim 1, wherein the regeneration temperature in step (3) is greater than 500 ℃ and less than or equal to 1000 ℃.

9. the method according to claim 1, wherein the regeneration time in the step (3) is 0.1 ~ 6 h.

Technical Field

The invention belongs to the technical field of energy, and particularly relates to a method for producing hydrogen by adsorption-enhanced reforming of lignin black liquor.

Background

In the pulp and paper industry, alkali liquor is commonly used to dissolve the lignin in the raw material for its removal, and the resulting cooking liquor containing inorganic salts and large amounts of lignin, cellulose and hemicellulose is commonly referred to as black liquor. The direct discharge of black liquor not only causes serious ecological damage and environmental pollution, but also is a great waste of biomass resources. Although the heat supply by black liquor combustion is applied to some industrial processes, the thermal efficiency is low, and the requirement of large-scale application cannot be met. In view of this, how to utilize black liquor efficiently is an important issue of industrial concern.

The hydrogen is an environment-friendly energy source, the energy density is high, and the combustion product only contains water, so that the environment is not polluted. With the increasing exhaustion of traditional fossil energy and the tightening of control on carbon emission, hydrogen energy is expected to become one of the main energy sources driving the economic development of the world in decades. The method for preparing hydrogen by using black liquor not only improves the utilization value of the black liquor, avoids the pollution to the environment caused by direct discharge of the black liquor, but also relieves the dependence of the existing hydrogen production process on fossil energy to a certain extent. Therefore, the prospect of preparing hydrogen by using the lignin black liquor is considerable.

because the composition of black liquor is complex, reports of its use for hydrogen production are still less. In the present technology of hydrogen production by using black liquor, the supercritical water gasification method is studied most. Patent JP2006257577-a reports the co-production of hydrogen and methane by supercritical water gasification of lignin black liquor; cao Changqing et al reported that the hydrogen production by supercritical water gasification by mixing black liquor and coal, the hydrogen concentration can reach 59.26% at 750 deg.C (Energy)&Fuels,2017,31: 13585-13592). They also report that supercritical water gasification of wheat straw black liquor is used to produce hydrogen, although the hydrogen yield can reach 0.75mol H at most₂Per mol C, but the hydrogen purity is only about 60 percent, and the gas still contains a large amount of CO₂、CH₄And CO (Energy)&Fuels,2017,31: 3970-3978). Can be used forIt is seen that the above black liquor hydrogen production process cannot obtain high purity hydrogen and needs to be operated at a high pressure of 22.1 MPa. If high purity Hydrogen is to be obtained, multiple subsequent purification and separation processes are required, but this adds significantly to the cost of Hydrogen production (International Journal of Hydrogen Energy,2009,34: 2350-2360).

Steam reforming hydrogen production is a widely used hydrogen production technology in industry by introducing CO into the steam reforming process₂The capture can move the reaction equilibrium to the direction of hydrogen generation, thereby greatly improving the purity and yield of the hydrogen, and the process is called as adsorption enhanced reforming hydrogen production. Patent WO2009115322-A2 reports that the purity of the obtained hydrogen can reach 99.5% by using the adsorption enhanced reforming hydrogen production technology of polyhydric alcohol. Patent CN108328574A reports that the conversion rate of phenol and the purity of hydrogen can reach 99% and 98%, respectively. Chen De et al, using a hydrotalcite-based catalyst with Pd as the active component, performed adsorption-enhanced reforming of bio-oil model compound acetic acid at 525 ℃ at normal pressure with hydrogen concentration and yield up to 99.5% and 90%, respectively (ChemSusChem,2014,7: 3063-3077). Yu Hao (chemical Engneeering journal,2019,360:47-53) et al utilize Ni as the catalytically active component and CaO as CO₂Trapping agent, Ca₁₂Al₁₄O₃₃The dual-function catalyst as a carrier is used for absorbing and enhancing the glycerol as the by-product of the biodiesel to reform steam to prepare hydrogen, the reaction is carried out at 550 ℃ and the desorption is carried out at 700 ℃ respectively under normal pressure, and the hydrogen concentration is maintained to be more than 98% in a 10-circle cycle experiment. The reports show that the adsorption enhanced reforming technology can prepare high-purity hydrogen, and compared with the supercritical water gasification technology, the technology has the advantages of mild process conditions and simple and convenient operation. However, the above reports all use high purity chemical reagents as the feedstock for adsorption enhanced reforming, and it is not expected that a similar catalyst will be used for hydrogen production from black liquor, which is far more complex in composition, to obtain high purity hydrogen.

Disclosure of Invention

The invention aims to provide a method for producing hydrogen by adsorption-enhanced reforming of lignin black liquor, which removes CO generated in the reforming process through adsorption₂One step directlyHigh-purity hydrogen is obtained.

The object of the invention is solved by at least one of the following solutions.

A method for producing hydrogen by adsorption-enhanced reforming of lignin black liquor comprises the following steps:

(1) Filling a Ni-Ca-Al powder catalyst in a reactor;

(2) Injecting lignin black liquor aqueous solution into a reactor by taking inert gas as carrier gas to carry out reforming hydrogen production;

(3) When CO is present₂after the adsorption of (a) is saturated, the catalyst is regenerated in an inert atmosphere.

Preferably, the mass content of Ni in the Ni-Ca-Al catalyst in the step (1) is 5-20%, and the catalyst has the functions of catalyzing and absorbing CO₂And (4) performing functions.

Preferably, in the step (1), the Ni-Ca-Al catalyst is Ni, CaO and Ca₁₂Al₁₄O₃₃A mixture of (a).

Preferably, the molar ratio of Ca to Al in the Ni-Ca-Al catalyst in the step (1) is 1.6-3.4: 1.

Preferably, the concentration of the lignin black liquor aqueous solution in the step (2) is 0.104-0.313g/ml, and more preferably 0.156-0.208 g/ml.

Preferably, the gas hourly space velocity of the lignin black liquor aqueous solution in the step (2) is 2000-9000 h^-1more preferably 4500-7500 h^-1。

Preferably, the reaction temperature in the step (2) is 400-700 ℃, and more preferably 500-650 ℃.

Preferably, the regeneration temperature in the step (3) is more than 500 ℃ and less than or equal to 1000 ℃; further preferably 750 to 850 ℃.

Preferably, the regeneration time in the step (3) is 0.1-6 h, and more preferably 1-2 h.

Compared with the prior art, the invention has the following advantages:

The purity of the hydrogen obtained by the adsorption-enhanced reforming process applied to the lignin black liquor is high (up to 96%), and in a 5-circle cycle experiment, the hydrogen is obtainedThe concentration is maintained above 96 percent, and the hydrogen yield is maintained at 0.9mol H₂More than/mol C. The method realizes effective reutilization of the black liquor, avoids pollution to the environment, and can obtain high-purity hydrogen without working under high pressure and subsequent separation and purification processes compared with the method for preparing hydrogen by using the black liquor in the prior art, thereby obviously reducing the cost of hydrogen preparation.

Drawings

FIG. 1 is an X-ray diffraction pattern of the Ni-Ca-Al catalyst of example 2.

Detailed Description

The following examples and drawings further illustrate the embodiments of the present invention, but the scope of the present invention is not limited to the following embodiments.

the hydrogen concentration in the following examples was determined by Gas Chromatography (GC) analysis, and the GC assay was quantified using an external standard method.