Preparation method of denitrification and deoxidation molecular sieve catalyst for hydrogen purification

Abstract

The invention discloses a denitrification and deoxidation molecular sieve catalyst for hydrogen purification. The denitrification and deoxidation molecular sieve catalyst is mainly prepared from the following raw materials in percentage by mass: 65-85% of zeolite powder; 10-25% of an adhesive; 5-9% of an auxiliary agent; 5-7% of graphene; 6-12% of a calcium-based compound; the sum of the mass percentages of the components is 100%. The invention also provides a preparation method of the denitrification and deoxidation molecular sieve catalyst for hydrogen purification. The preparation method mainly depends on the mixed sintering action of various materials, and the reaction mechanism is as follows: a calcium base and graphene are subjected to a heating reaction, the thermochemical energy storage action of the calcium base is involved, crystal formation between the calcium base and graphene is promoted, and meanwhile, after the calcium base and a zeolite material are subjected to a heating reaction, crystal formation between the calcium base and the graphene is promoted. The pore structure of the molecular sieve is improved; and the adsorption and desorption capability of the molecular sieve catalyst is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen purification, in particular to a method for preparing a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification. Background Art

[0002] Hydrogen energy is a green, low-carbon and abundant secondary energy source with wide applications. It is gradually becoming one of the important carriers of global energy transformation and development. Hydrogen energy has become a strategic choice to accelerate energy transformation and upgrading and cultivate new economic growth.

[0003] my country currently produces about 33 million tons of hydrogen annually, of which about 12 million tons meet industrial hydrogen quality standards, and there are more than 300 hydrogen production companies above the industrial chain scale. It is very important to promote the integration of hydrogen energy, electricity and thermal energy systems and promote the formation of an industrial chain of modern energy and supply systems. With green and low-carbon as the principle, accelerate the green supply of hydrogen energy. The country has deployed the construction of a number of hydrogen refueling stations, and the production of hydrogen from renewable energy has reached 100,000 to 200,000 tons / year, becoming an important part of the new hydrogen energy consumption, and achieving a carbon dioxide emission reduction of 1 million to 2 million tons / year.

[0004] The existing hydrogen purification process needs to be improved. Only after the impurities nitrogen and oxygen in hydrogen are removed and separated can pure hydrogen be truly achieved. Because coal-to-hydrogen, photoelectrolysis of water to produce hydrogen, nuclear high-temperature hydrogen production and other processes all contain N2 and O2 in the hydrogen used, and the nitrogen and oxygen removal process involves the recovery of N2 and O2 after removal, the adsorbent used is required to have the functions of adsorption separation, removal and recovery. Therefore, the traditional single catalyst cannot complete the task, and it is urgent to develop a molecular sieve catalyst with good adsorption and desorption functions for nitrogen and oxygen in hydrogen. Summary of the invention

[0005] The present invention aims to at least partially overcome the above technical problems and / or other potential problems existing in the prior art: to provide a method for preparing a denitrification and deoxygenation molecular sieve catalyst for hydrogen purification. The molecular sieve catalyst of the present invention has a good adsorption and separation effect on nitrogen and oxygen in hydrogen.

[0006] The technical solution of the present invention is as follows: a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification, mainly made of the following raw materials in the following mass percentages: zeolite powder 65-85%; binder 10-25%; additive 5-9%; graphene 5-7%; calcium-based compound 6-12%; the sum of the mass percentages of the above components is 100%.

[0007] As an optimization, the zeolite powder is one or a mixture of two of Cax type and Nax type zeolite powders.

[0008] As an optimization, the binder is a mixture of one or more of attapulgite, attapulgite and kaolin.

[0009] As an optimization, the auxiliary agent is a mixture of one or more of sodium carboxymethyl cellulose (CMC), sodium hydroxypropyl methylcellulose (HPMC), sesbania powder plant gum (SG), bayberry tannin extract (MOL) and sodium pyrophosphate (Na4P2O7).

[0010] As an optimization, the calcium-based compound is a mixture of one or more of CaCl2, CaO, Ca(NO3)2, CaCO3 and CaC2.

[0011] The invention provides a preparation method of a denitrification and deoxygenation molecular sieve catalyst for hydrogen purification. The method comprises the following steps: firstly, zeolite powder, a binder and an auxiliary agent are uniformly mixed, then the mixture is put into a kneader together with graphene and a calcium-based compound, water accounting for 30-35% of the total amount of the materials is added, kneading with water for 3-4 hours, and after kneading into a mud material, the mud material is put into a reaction kettle, the temperature is set at 110-130 DEG C, constant temperature reaction is performed for 18-24 hours, and then extrusion granulation is performed, after granulation, the particles are put into a constant temperature drying oven at 110-150 DEG C and dried until the moisture content of the particles is less than 10%, and then calcined and activated at a temperature of 575-620 DEG C for 2-3 hours, and cooled to room temperature to obtain the denitrification and deoxygenation molecular sieve catalyst for hydrogen purification.

[0012] The present invention also provides a preparation method of a denitrification and deoxygenation molecular sieve catalyst for hydrogen purification, comprising the following steps: firstly, zeolite powder, a binder and an auxiliary agent are uniformly mixed, then mixed with graphene and a calcium-based compound and placed in a reaction kettle, the temperature is set at 110-130°C, constant temperature reaction is carried out for 18-24 hours, and then pelletization is carried out, after granulation, the particles are placed in a constant temperature drying oven at 110-150°C and dried until the moisture content of the particles is less than 10%, and then calcined and activated at a temperature of 575-620°C for 2-3 hours, and cooled to room temperature to obtain the denitrification and deoxygenation molecular sieve catalyst for hydrogen purification.

[0013] The beneficial effects of the present invention are as follows: zeolite has a high adsorption and separation effect. Using zeolite as a carrier not only increases the active components of the catalyst, but also can first adsorb impurities such as moisture and NOx in the gas. Zeolite has a good affinity with graphite and calcium and an absorption rate of chelated calcium. Graphene can not only remove nitrogen, but also transform and utilize nitrogen molecules. It has a high conductivity in the electrolysis value and shows unique potential in capturing nitrogen. Calcium base has good acid resistance and heat resistance.

[0014] The molecular sieve catalyst of the present invention can remove nitrogen and oxygen from hydrogen. Hydrogen can be purified to pure hydrogen so that hydrogen can be converted into green hydrogen or green alcohol through a hydrogenation reaction. The present invention uses zeolite as a carrier and graphene and calcium base as active capture agents to achieve good adsorption and desorption effects on nitrogen and oxygen in hydrogen. First, the pore structure of the catalyst must meet the required requirements so that the adsorbed nitrogen and oxygen molecules will not penetrate, and it is also necessary to consider that hydrogen cannot be adsorbed. Because hydrogen, nitrogen, and oxygen all have smaller chemical molecular diameters, the present invention uses the amphiphilic binding points of the molecular sieve and the catalyst, which are selectively captured by graphene and calcium base respectively, and then selectively separated by the molecular sieve.

[0015] The present invention mainly relies on the mixed sintering activation effect of multiple characteristic materials, and its reaction mechanism is: the calcium base and graphene are heated to react, which involves the thermochemical energy storage effect of the calcium base, promoting the formation of crystals between the calcium base and the graphene. At the same time, after the calcium base and the zeolite material are heated to react, the pore structure of the molecular sieve is improved and the adsorption and desorption capacity of the molecular sieve catalyst is improved. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with specific examples, but the present invention is not limited to the following specific examples.

[0017] Example 1

[0018] The molecular sieve catalyst of the present invention is a research and development product specially used for hydrogen purification, nitrogen removal and oxygen removal. First, the raw powder of domestic superior zeolite Cax type and Nax type is selected, and each raw material is weighed according to the following mass percentage: zeolite powder 65%; binder 17%; auxiliary agent 5%; graphene 5%; calcium-based compound 8%; the zeolite powder is a mixture of Cax type and Nax type zeolite powder in equal weight ratio; the binder is a mixture of chamomile, attapulgite and kaolin in equal weight ratio. The auxiliary agent is a mixture of sodium carboxymethyl cellulose (CMC), sesbania powder plant gum (SG), and bayberry tannin extract (MOL) in equal weight ratio. The calcium-based compound is a mixture of CaCl2, CaO and CaCO3 in equal weight ratio.

[0019] First, zeolite powder, binder and additives are mixed evenly, and then put into a kneading machine together with graphene and calcium-based compounds, and water accounting for 35% of the total amount of the materials is added, and kneading with water is carried out for 3 hours. After kneading into a mud material, the mud material is put into a reactor, and the temperature is set to 115°C. After constant temperature reaction for 24 hours, extrusion granulation is carried out. After granulation, the particles are placed in a constant temperature drying oven and dried at 110°C until the moisture content of the particles is less than 10%. Only then can they be high-temperature calcined (otherwise, the particles will burst due to excessive moisture), and then calcined and activated at a temperature of 575°C for 3 hours, and cooled to room temperature to obtain strip-shaped denitrogenation and deoxygenation molecular sieve catalysts for hydrogen purification.

[0020] The strip molecular sieve catalyst of Example 1 has a diameter of 1 / 16, 1.5-1.7 mm, and a length of 4-7 mm. The various indicators after testing are shown in the following table:

[0021]

[0022] Example 2

[0023] First, weigh the raw materials according to the following mass percentages: 65% zeolite powder; 17% binder; 5% auxiliary agent; 5% graphene; 8% calcium-based compound; the zeolite powder is a mixture of Cax-type and Nax-type zeolite powders in equal weight ratio; the binder is molten clay. The auxiliary agent is a mixture of sodium carboxymethyl cellulose (CMC) and bayberry tannin extract (MOL) in equal weight ratio. The calcium-based compound is a mixture of CaCl2, CaO and CaC2 in equal weight ratio.

[0024] First, zeolite powder, binder and additives are put into a mixer and mixed for 2 hours, and then graphene and calcium-based compounds are put into the mixer and mixed again for 2 hours. This process can only be dry mixed, and water or other adhesives are not allowed. Then the mixed raw materials are put into a reactor, the temperature is set to 110°C, and after constant temperature reaction for 24 hours, ball making and granulation are carried out. The granulation shape is spherical particles. The particles are placed in a constant temperature drying oven and dried at 150°C for 2 hours until the moisture content of the particles is less than 10%, and then calcined and activated at 600°C for 3 hours, and cooled to room temperature to obtain a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification.

[0025] The various indicators of the spherical molecular sieve catalyst of this embodiment 2 after testing are shown in the following table:

[0026]

[0027] Example 3

[0028] First, weigh the raw materials according to the following mass percentages: zeolite powder 70%; binder 10%; auxiliary agent 7%; graphene 7%; calcium-based compound 6%; the zeolite powder is Cax type zeolite powder; the binder is a mixture of tartaric acid and attapulgite in equal weight ratios. The auxiliary agent is a mixture of sodium carboxymethyl cellulose (CMC), sodium hydroxypropyl methylcellulose (HPMC), bayberry tannin extract (MOL) and sodium pyrophosphate (Na4P2O7) in equal weight ratios. The calcium-based compound is a mixture of CaCl2, CaO and CaCO3 in equal weight ratios.

[0029] First, zeolite powder, binder and additives are put into a mixer and mixed for 3 hours, and then graphene and calcium-based compounds are put into the mixer and mixed again for 2 hours. This process can only be dry mixed without adding water or other adhesives. Then the mixed raw materials are put into a reactor, the temperature is set to 110°C, and after constant temperature reaction for 18 hours, ball making and granulation are carried out. The granulation shape is spherical particles. The particles are placed in a constant temperature drying oven and dried at 110°C for 3 hours until the moisture content of the particles is less than 10%, and then calcined and activated at 620°C for 3 hours, and cooled to room temperature to obtain a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification.

[0030] The various indicators of the spherical molecular sieve catalyst of this embodiment 3 after testing are shown in the following table:

[0031]

[0032] Example 4

[0033] First, weigh the raw materials according to the following mass percentages: 74% zeolite powder; 10% binder; 5% auxiliary agent; 5% graphene; 6% calcium-based compound; the zeolite powder is Cax type zeolite powder; the binder is a mixture of chamotte and attapulgite in equal weight ratios. The auxiliary agent is a mixture of sodium carboxymethyl cellulose (CMC), sodium hydroxypropyl methylcellulose (HPMC), bayberry tannin extract (MOL) and sodium pyrophosphate (Na4P2O7) in equal weight ratios. The calcium-based compound is a mixture of CaCl2, CaO and CaCO3 in equal weight ratios.

[0034] First, zeolite powder, binder and additives are put into a mixer and mixed for 2 hours, and then graphene and calcium-based compounds are put into the mixer and mixed again for 2 hours. This process can only be dry mixed without adding water or other adhesives. Then the mixed raw materials are put into a reactor, the temperature is set to 130°C, and after constant temperature reaction for 20 hours, ball making and granulation are carried out. The granulation shape is spherical particles. The particles are placed in a constant temperature drying oven and dried at 120°C for 3 hours until the moisture content of the particles is less than 10%, and then calcined and activated at 620°C for 2 hours, and cooled to room temperature to obtain a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification.

[0035] The various indicators of the spherical molecular sieve catalyst of this embodiment 4 after testing are shown in the following table:

[0036]

[0037] Example 5

[0038] First, weigh the raw materials according to the following mass percentages: 70% zeolite powder; 12% binder; 7% auxiliary agent; 5% graphene; 6% calcium-based compound; the zeolite powder is Cax type zeolite powder; the binder is a mixture of kaolin, attapulgite and kaolin in equal weight ratios. The auxiliary agent is a mixture of sodium carboxymethyl cellulose (CMC), sesbania powder plant gum (SG) and sodium pyrophosphate (Na4P2O7) in equal weight ratios. The calcium-based compound is a mixture of CaCl2, CaO and CaCO3 in equal weight ratios.

[0039] First, put zeolite powder, binder and additives into a mixer and mix for 2 hours, then put them into a kneader together with graphene and calcium-based compounds, add 35% of water to the total amount of the materials, knead with water for 4 hours, and after kneading into mud, put the mud into a reactor, set the temperature to 130°C, and react at a constant temperature for 18 hours before extrusion granulation. The granulation is in the form of strips, which are extruded using a standard die of an extruder 1 / 8, 3.1-3.3mm to extrude the required strip particles. After granulation, put the particles into a constant temperature drying oven and dry them at 150°C until the moisture content of the particles is less than 10%. Only then can they enter high-temperature calcination (otherwise the particles will burst if the moisture content is too high), and then calcine and activate at 620°C for 2 hours, and cool to room temperature to obtain strip-shaped denitrogenation and deoxygenation molecular sieve catalysts for hydrogen purification.

[0040] The strip molecular sieve catalyst of Example 5 has a 1 / 8 diameter of 3.1-3.3 mm and a length of 4-10 mm. The various indicators after testing are shown in the following table:

[0041]

[0042] By comparing the test results of the above embodiments, it can be seen that the molecular sieve catalyst of embodiment 3 has the best adsorption performance.

[0043] The above are only examples of the characteristic implementation of the present invention, and do not constitute any limitation on the protection scope of the present invention. Any technical solution formed by equivalent exchange or equivalent replacement shall fall within the protection scope of the present invention.

Claims

1. A denitrification and deoxygenation molecular sieve catalyst for hydrogen purification, characterized in that: It is mainly made of the following raw materials in the following mass percentages: zeolite powder 65-85%; binder 10-25%; additive 5-9%; graphene 5-7%; calcium-based compound 6-12%; the sum of the mass percentages of the above components is 100%.

2. The denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claim 1, characterized in that: The zeolite powder is one of Cax type and Nax type zeolite powder or a mixture of both.

3. The denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claim 2, characterized in that: The binder is a mixture of one or more of attapulgite, attapulgite and kaolin.

4. The denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claim 3, characterized in that: The auxiliary agent is a mixture of one or more of sodium carboxymethyl cellulose (CMC), sodium hydroxypropyl methyl cellulose (HPMC), sesbania powder plant gum (SG), bayberry tannin extract (MOL) and sodium pyrophosphate (Na4P2O7).

5. The denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claim 4, characterized in that: The calcium-based compound is a mixture of one or more of CaCl2, CaO, Ca(NO3)2, CaCO3 and CaC2.

6. A method for preparing the denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claims 1-5, characterized in that: First, zeolite powder, binder and additives are mixed evenly, and then put into a kneader together with graphene and calcium-based compounds, and water accounting for 30-35% of the total amount of the materials is added, and kneading with water is carried out for 3-4 hours. After kneading into a mud material, the mud material is put into a reactor, and the temperature is set at 110-130°C. After constant temperature reaction for 18-24 hours, extrusion granulation is carried out. After granulation, the particles are placed in a constant temperature drying oven at 110-150°C and dried until the moisture content of the particles is less than 10%, and then calcined and activated at a temperature of 575-620°C for 2-3 hours, and cooled to room temperature to obtain a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification.

7. A method for preparing the denitrification and deoxygenation molecular sieve catalyst for hydrogen purification according to claims 1-5, characterized in that: First, zeolite powder, binder and additives are mixed evenly, then mixed with graphene and calcium-based compounds and put into a reactor, the temperature is set at 110-130°C, and the constant temperature reaction is carried out for 18-24 hours before pelletizing and granulation. After granulation, the particles are placed in a constant temperature drying oven at 110-150°C and dried until the moisture content of the particles is less than 10%, and then calcined and activated at 575-620°C for 2-3 hours, and cooled to room temperature to obtain a denitrogenation and deoxygenation molecular sieve catalyst for hydrogen purification.

Images