Activated carbon for vehicle and method for producing the same

Abstract

The application provides a kind of activated carbon for vehicle and its preparation method, the preparation raw material of the activated carbon for vehicle includes matrix material after physical activation and alkali metal complex salt;The alkali metal complex salt includes the combination of any two or three in alkali metal chlorides, alkali metal phosphates or alkali metal borate;The mass ratio of metal ion and matrix material in the activated carbon for vehicle is (0.5-5):100.The preparation method provided by the application adopts fluidized bed combined with physical activation, at 850-1100 DEG C, the complex salt is melted to form molten salt, and the diffusion of complex molten salt is strengthened by violent particle movement, so as to promote the uniform dispersion of molten salt, so that the activated carbon for vehicle can be obtained at lower activation temperature and shorter activation time than fixed bed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of activated carbon processing, and relates to a kind of vehicle activated carbon and its preparation method, especially to a kind of vehicle activated carbon preparation method using fluidized bed activation method. BACKGROUND

[0002] Vehicle carbon tank utilizes the adsorption and desorption characteristics of activated carbon to adsorb the steam generated by the fuel system in the activated carbon tank, preventing the fuel system from being directly discharged to the atmosphere due to respiration. Then, through the vacuum degree at the engine intake manifold, the fuel vapor in the activated carbon tank is desorbed and introduced into the engine cylinder to participate in combustion, achieving control and regeneration. Vehicle activated carbon requires a high proportion of mesopores with a diameter of 2-5 nm to facilitate adsorption and desorption of oil gas.

[0003] CN 1865133A discloses a preparation method for adsorbing gasoline vapor activated carbon, which uses waste wood plants as raw materials. After drying, the materials are sequentially soaked in H3PO4 for 2-3 hours, then soaked in sodium hydroxide for 1-2 hours for secondary activation, and finally washed with hydrochloric acid to obtain vehicle activated carbon. CN 103588204A discloses a preparation method for coal-based vehicle oil and gas recovery special activated carbon, which uses Ningxia Taixi non-smoke washed fine coal, pitch, and tar as raw materials, and adopts a process of twice water vapor activation with intermediate acid washing to obtain vehicle activated carbon. CN 1815007A discloses an activated carbon and its manufacturing method, which uses physical method to prepare vehicle activated carbon, specifically including using non-smoke coal containing 70% carbon and less than 4% ash content as raw material, adding pitch and tar binder, first activating at 800℃ for 20 hours in a mixed gas of carbon dioxide, nitrogen, and water vapor, then re-heating to 980℃ for 18-24 hours to obtain vehicle activated carbon.

[0004] In the above-mentioned patents, CN 1865133A discloses a chemical activation method, and CN 103588204A and CN 1815007A disclose physical activation methods. The steps of chemical and physical activation methods are complicated and time-consuming. In view of the above technical problems, it is necessary to provide a vehicle carbon preparation method with lower activation temperature and shorter activation time than fixed bed activation. SUMMARY

[0005] To overcome the shortcomings of the prior art, the present application provides a kind of vehicle activated carbon and its preparation method. The present application uses fluidized bed combined with physical activation. At high temperature, alkali metal complex salt melts to form molten salt. The intense particle movement enhances the diffusion of complex molten salt, thereby promoting the uniform dispersion of molten salt. Therefore, vehicle activated carbon can be obtained at a lower activation temperature and shorter activation time than fixed bed.

[0006] To achieve the above object, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a vehicle activated carbon, wherein the raw material for preparing the vehicle activated carbon comprises a base material after physical activation and an alkali metal composite salt;

[0008] The alkali metal composite salt comprises any two or three of alkali metal chloride salt, alkali metal phosphorus salt or alkali metal boron salt, and typical but non-limiting combinations include: a combination of alkali metal chloride salt and alkali metal phosphorus salt, a combination of alkali metal phosphorus salt and alkali metal boron salt, a combination of alkali metal chloride salt and alkali metal boron salt, or a combination of alkali metal chloride salt, alkali metal phosphorus salt and alkali metal boron salt.

[0009] The mass ratio of metal ions to base material in the vehicle activated carbon is (0.5-5):100, for example, it can be 0.5:100, 1:100, 2:100, 3:100, 4:100 or 5:100, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0010] The specific surface area of the vehicle activated carbon provided by the present application is >1200m 2 / g, the pore volume is >1cm 3 / g, the mesopore volume is >0.5cm 3 / g, the butane working capacity (BWC) is >10g / 100ml, and the strength is >85%.

[0011] The physical activation process of the base material in the present application is: first carbonization treatment of the base material under an inert gas atmosphere, and then activation treatment under a carbon dioxide and / or water vapor atmosphere.

[0012] As a preferred technical solution of the present application, when the alkali metal composite salt is a mixture of alkali metal chloride salt and alkali metal boron salt, the molar ratio of chlorine element to boron element is 1:(4-28), for example, it can be 1:4, 1:8, 1:12, 1:16, 1:20, 1:24 or 1:28, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0013] Preferably, when the alkali metal composite salt is a mixture of alkali metal chloride salt, alkali metal phosphorus salt and alkali metal boron salt, the molar ratio of chlorine element to the sum of boron element and phosphorus element is Cl:(P+B) 1:(5-35), for example, it can be 1:5, 1:10, 1:15, 1:20, 1:25, 1:30 or 1:35, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0014] Preferably, when the alkali metal composite salt is a mixture of alkali metal chlorides and alkali metal phosphates, the molar ratio of chlorine element to phosphorus element is 1:(1-7), which can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or 1:7, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0015] Preferably, when the alkali metal composite salt is a mixture of alkali metal chlorides and alkali metal phosphates, the molar ratio of chlorine element to phosphorus element is 1:(1-7), which can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or 1:7, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0016] It is worth noting that there is a synergistic effect among the alkali metal chlorides, alkali metal phosphates and alkali metal borates in the alkali metal composite salt in the present application. First, the type of combination can be selected according to the design requirements of BWC. The activity of BWC and the alkali metal composite salt in catalyzing carbon dioxide / water vapor is positively correlated, and the ranking of catalytic activity is: alkali metal chlorides and borate composite salts > chlorides, phosphates and borate composite salts > phosphates and borate composite salts > chlorides and phosphates composite salts; second, under the premise of meeting the BWC, the ratio of the composite salt is selected according to the need of the flushing rate. The present application selects the above ratio, if the ratio is too low, it will lead to insufficient catalytic activity of the vehicle activated carbon, and if the ratio is too high, it will lead to insufficient mesopore ratio in the vehicle activated carbon.

[0017] It is worth noting that the alkali metal chlorides in the present application include sodium chloride and / or potassium chloride, wherein the melting point of sodium chloride is 801℃, and the melting point of potassium chloride is 770℃.

[0018] Preferably, the alkali metal phosphates include any one or a combination of at least two of the alkali metal orthophosphates and their acid salts, polyphosphates, pyrophosphates and their acid salts, metaphosphates or poly-metaphosphates, preferably sodium orthophosphate and its acid salt and / or potassium orthophosphate and its acid salt.

[0019] Preferably, the alkali metal borates include any one or a combination of at least two of the alkali metal borates, pyroborates, metaborates or tetraborates, preferably sodium tetraborate and / or potassium tetraborate.

[0020] It needs to be further explained that the minimum activation temperature of carbon dioxide and / or water vapor in the fluidized bed activation process in the preparation process is 850℃, in order to ensure that the alkali metal composite salt can form a molten salt above the minimum activation temperature, the melting point of the alkali metal borate and the alkali metal phosphate is <800℃.

[0021] As a preferred technical solution of the present application, the base material includes any one or a combination of at least two of plant material, mineral material, natural raw material or synthetic material, and typical but non-limiting combinations include a combination of plant material and mineral material, a combination of plant material, mineral material and natural raw material, a combination of natural raw material and synthetic material, or a combination of plant material, mineral material, natural raw material and synthetic material.

[0022] Specifically, the plant activated carbon includes carbonaceous raw materials such as wood, coconut shell and the like nut shell raw materials; mineral raw materials include coal, pitch, coke or petroleum coke and the like; natural raw materials include natural fibers such as hemp, cotton and the like, regenerated fibers such as rayon, viscose rayon and the like, semi-synthetic fibers such as acetate, triacetate and the like; and synthetic materials include polyacrylonitrile, phenolic resin, polyvinylidene chloride, polycarbonate, polyvinyl alcohol.

[0023] Preferably, the particle size of the base material is 0.05-3.00 mm, for example, it can be 0.05 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0024] The particle size of the base material of the present application is 0.05-3.00 mm, and if the particle size is too fine, it will lead to escape from the reaction device due to air flow during the preparation process (fluidized bed activation treatment); if the particle size is too coarse, it will not only lead to insufficient entry and adhesion of the activator into the pores of the base material during contact between the raw material and the activator, but also lead to failure of the base material to roll normally and failure to achieve fluidization.

[0025] Preferably, the specific surface area of the base material is 20-1000 m 2 / g, for example, it can be 20 m 2 / g, 100 m 2 / g, 300 m 2 / g, 500 m 2 / g, 700 m 2 / g or 1000 m 2 / g, but is not limited to the listed values, and other values not listed within the value range are also applicable; preferably, it is 600-1000 m 2 / g.

[0026] The specific surface area of the base material of the present application is 20-1000 m 2 / g, and the greater the specific surface area, the more the activator can be dispersed and adhered to the surface and pores of the base material, thereby reducing the amount of activator used.

[0027] In a second aspect, the present application provides a preparation method of the activated carbon for vehicles as provided in the first aspect, and the preparation method comprises the following steps:

[0028] (1) mixing the physically activated base material and the aqueous solution of the alkali metal composite salt according to the formula, and then performing fluidized bed activation treatment to obtain a precursor material;

[0029] (2) washing the precursor material obtained in step (1), and then sequentially performing primary drying treatment, crushing, extrusion molding, and secondary drying treatment to obtain the activated carbon for vehicles.

[0030] In the present application, the alkali metal composite salt with catalytic activity and mesopore forming function is designed and loaded on the surface and pores of the granular base material. In the process of using the fluidized bed high-temperature oxidation reaction to etch and pore-form the activated carbon, the composite salt melts to form a molten salt, and the intense particle movement strengthens the diffusion of the molten salt in the particles, thereby promoting the uniform dispersion of the molten salt. Therefore, not only is the catalytic reaction activity strengthened and the activation temperature reduced, but also sufficient mesopores can be formed in a short time. Compared with the fixed bed, the composite salt coupled with the fluidized bed physical activation provided in the present application can expand the pores and increase the capacity at a lower temperature and in a shorter time, realize pore size control, and meet the performance requirements of the activated carbon for vehicles.

[0031] The functional description of the alkali metal composite salt in the present application includes that carbon dioxide and water vapor are the main activation agents in the physical activation process, and the high-carbon raw material undergoes oxidation pyrolysis in the carbon dioxide and water vapor activation and the etching and pore-forming process. The main reactions responsible for the activation are C+CO2→CO or C+H2O→H2+CO, C+2H2O→2H2+CO2. The catalytic activity of the alkali metal salt is ranked as follows: alkali metal boron salt > alkali metal chloride salt > alkali metal phosphorus salt, and the mesopore forming ability is ranked as follows: alkali metal phosphorus salt > alkali metal boron salt > alkali metal chloride salt. When any one of the alkali metal salts is used alone, its activation ability and mesopore forming ability are weak, which leads to the pore performance of the prepared activated carbon failing to meet the performance requirements of the activated carbon for vehicles.

[0032] It is worth noting that the mixing in step (1) is not limited to the mixing method, as long as the base material contains the alkali metal composite salt. The mixing method can be a method of spraying the aqueous solution of the alkali metal composite salt while mixing the base material, a method of immersing the raw material in the aqueous solution of the composite salt, etc. Through this contact, the composite salt adheres to the surface or pores of the base material.

[0033] As a preferred technical solution of the present application, the activation gas used in the fluidized bed activation treatment in step (1) comprises carbon dioxide and / or water vapor.

[0034] Preferably, the flow rate of the activating gas used in the fluidized bed activation process of step (1) is 1-5 times the minimum fluidization velocity of the fluidized bed, for example, it can be 1 times, 1.5 times, 2 times, 3 times, 4 times or 5 times, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0035] As a preferred technical solution of the present application, the activation temperature of the fluidized bed activation process of step (1) is 850-1100℃, for example, it can be 850℃, 900℃, 950℃, 1000℃, 1050℃ or 1100℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0036] The activation temperature of the present application is 850-1100℃, if the activation temperature is too low, the alkali metal complex salt cannot form a molten salt, resulting in insufficient activation; if the activation temperature is too high, the activation degree is excessive.

[0037] Preferably, the residence time of the fluidized bed activation process of step (1) is 5-30min, for example, it can be 5min, 9min, 13min, 17min, 21min, 25min or 30min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0038] The residence time of the present application is 5-30min, if the residence time is too short, the activation degree is insufficient; if the residence time is too long, the activation is excessive, and the yield is reduced.

[0039] Preferably, inert particles are supplemented in the fluidized bed in the fluidized bed activation process of step (1).

[0040] Preferably, the inert particles include any one or a combination of at least two of river sand, silica sand or dolomite, typical but non-limiting combinations include: a combination of river sand and silica sand, a combination of silica sand and dolomite, a combination of river sand and dolomite, or a combination of river sand, silica sand and dolomite.

[0041] Preferably, the mass ratio of the inert particles to the preparation raw material is >1:4, for example, it can be 1:3.9, 1:3.8, 1:3.7, 1:3.6, 1:3.5, 1:3.4, 1:3.3, 1:3.2 or 1:3.1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0042] The present application mixes the base material and inert particles to form a two-component mixture, which is easier to achieve fluidization in the fluidized bed.

[0043] As a preferred technical solution of the present application, the cleaning of step (2) includes acid washing and water washing in sequence.

[0044] Preferably, the pickling solution used in the pickling process comprises hydrochloric acid, and the mass concentration of the hydrochloric acid is 0.1-15 wt%, for example, it can be 0.1 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 11 wt%, 13 wt% or 15 wt%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0045] Preferably, the pickling time is 10 min-24 h, for example, it can be 10 min, 30 min, 1 h, 3 h, 5 h, 9 h, 12 h, 15 h, 18 h, 20 h, 22 h or 24 h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0046] Preferably, the pickling temperature is 10-80℃, for example, it can be 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0047] It is worth noting that the pickling process described in the present application can be intermittent pickling or continuous pickling. For example, the intermittent pickling is 10 min each time, and the pickling is repeated 3 times.

[0048] Preferably, the water washing temperature is 10-120℃, for example, it can be 10℃, 20℃, 40℃, 60℃, 80℃, 100℃ or 120℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0049] Preferably, the water washing time is 1-24 h, for example, it can be 1 h, 3 h, 5 h, 9 h, 12 h, 15 h, 18 h, 20 h, 22 h or 24 h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0050] Preferably, the end point of the cleaning is that the pH of the washing solution is neutral.

[0051] Preferably, the temperature of the first drying process is 80-200℃, for example, it can be 80℃, 100℃, 120℃, 140℃, 160℃, 180℃ or 200℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0052] As a preferred technical solution of the present application, a supplemental binder is used in the extrusion molding of step (2).

[0053] Preferably, the binder comprises any one or a combination of at least two of a cellulose-based binder, a bentonite-based binder, or a resin-based adhesive, typically but not limited to a combination of a cellulose-based binder and a bentonite-based binder, a cellulose-based binder and a resin-based adhesive, a bentonite-based binder and a resin-based adhesive, or a combination of a cellulose-based binder, a bentonite-based binder, and a resin-based adhesive.

[0054] Preferably, the mass ratio of the binder to the precursor material is (1-20): 100, for example, it can be 1:100, 4:100, 8:100, 12:100, 16:100, or 20:100, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0055] Preferably, the cellulose-based binder comprises any one or a combination of at least two of carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, or hydroxyethyl methyl cellulose, typically but not limited to a combination of hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose, carboxymethyl cellulose and methyl cellulose, or a combination of carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl methyl cellulose.

[0056] Preferably, the bentonite-based binder comprises any one or a combination of at least two of bentonite, white clay, or knot clay, typically but not limited to a combination of bentonite and white clay, bentonite and knot clay, white clay and knot clay, or a combination of bentonite, white clay, and knot clay.

[0057] Preferably, the resin-based adhesive comprises phenolic resin and / or polyvinyl alcohol.

[0058] As a preferred technical solution of the present application, water can be supplemented in the extrusion molding of step (2).

[0059] Preferably, the mass ratio of the water to the precursor material is (10-250): 100, for example, it can be 10:100, 30:100, 50:100, 80:100, 120:100, 150:100, 180:100, 200:100, 220:100, or 250:100, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0060] The purpose of supplementing water in the extrusion molding process of the present application is to adjust the hardness of the molded product.

[0061] Preferably, the extrusion molding results in cylindrical pellets.

[0062] Preferably, the diameter of the cylindrical pellets is 1.5-2.5 mm, for example, 1.5 mm, 1.7 mm, 1.9 mm, 2.1 mm, 2.3 mm or 2.5 mm, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0063] The contents of the binder and water supplemented in the extrusion process of the preparation method affect the strength of the activated carbon for vehicles, and in order to make the activated carbon for vehicles have good strength (> 85%), the addition amounts of the binder and water need to be strictly controlled.

[0064] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0065] (1) mixing the physically activated base material and the aqueous solution of alkali metal complex salt according to the formula, and then performing fluidized bed activation treatment under an activation gas to obtain a precursor material;

[0066] The flow rate of the activation gas is 1-5 times the minimum fluidization velocity of the fluidized bed; the activation temperature is 850-1100℃, and the residence time is 5-30 min; inert particles are supplemented in the fluidized bed during the fluidized bed activation treatment; and the mass ratio of the inert particles to the raw materials is > 1:4.

[0067] (2) washing the precursor material obtained in step (1), and then sequentially performing primary drying treatment, crushing, extrusion molding and secondary drying treatment to obtain cylindrical pellet-shaped activated carbon for vehicles with a diameter of 1.5-2.5 mm;

[0068] The washing includes acid washing and water washing in sequence; the acid washing is washing with 0.1-15wt% hydrochloric acid at 10-80℃ for 10 min-24 h; and the water washing is washing with deionized water at 10-120℃ for 1-24 h.

[0069] The temperature of the primary drying treatment is 80-200℃;

[0070] The binder is supplemented in the extrusion molding; and the mass ratio of the binder to the precursor material is (1-20):100.

[0071] The following are preferred technical solutions of the present application, but are not limitations on the technical solutions provided by the present application. Through the following preferred technical solutions, the purposes and beneficial effects of the present application can be better achieved and realized.

[0072] Compared with the prior art, the present application has the following beneficial effects:

[0073] (1) The vehicle active carbon provided by the application meets the performance requirements of vehicle carbon, and has a specific surface area of >1200 m 2 / g, a pore volume of >1 cm 3 / g, a mesopore pore volume of >0.5 cm 3 / g, a butane working capacity (BWC) of >10 g / 100 ml, and a strength of >85 %.

[0074] (2) The vehicle active carbon is prepared by using a fluidized bed combined with physical activation, thereby reducing the activation temperature and shortening the activation time. DETAILED DESCRIPTION

[0075] In order to facilitate the understanding of the application, the application is illustrated by the following examples. It should be understood by those skilled in the art that the examples are only used to help understand the application and should not be regarded as a specific limitation on the application.

[0076] Example 1

[0077] The present example provides a vehicle active carbon, and a preparation method of the vehicle active carbon comprises the following steps:

[0078] (1) 1000 g of coconut shell active carbon (a specific surface area of 600 m 2 / g, a pore volume of 0.29 cm 3 / g, a micropore pore volume of 0.27 cm 3 / g, a mesopore pore volume of 0.02 cm 3 / g) after physical activation and having a particle size of 1 mm is impregnated in an aqueous solution of NaCl and NaH2PO4 (Cl / P = 1:1.3) with a metal ion concentration of 5 wt% for 2 hours, filtered, dried, and then subjected to fluidized bed activation treatment under carbon dioxide to obtain a precursor material;

[0079] The flow rate of the carbon dioxide is the minimum fluidization velocity of the fluidized bed, the activation temperature is 850 ℃, and the residence time is 20 min; river sand is supplemented in the fluidized bed during the fluidized bed activation treatment; and the mass ratio of the river sand to the preparation raw material is 1:3.5.

[0080] (2) The precursor material obtained in step (1) is washed, and then subjected to a first drying treatment, crushing, extrusion molding, and a second drying treatment in sequence to obtain a cylindrical granular vehicle active carbon with a diameter of 2.0 mm;

[0081] The washing includes acid washing and water washing in sequence; the acid washing is intermittent washing at 80 ℃ for 30 min (10 min for each acid washing, and the acid washing is repeated for 3 times) by using hydrochloric acid with a mass concentration of 3 wt%; and the water washing is repeated washing at 100 ℃ for 20 h by using deionized water until the pH value of the washing liquid is 7.

[0082] The temperature of the first drying treatment is 200℃.

[0083] Carboxymethyl cellulose is supplemented in the extrusion molding; the mass ratio of the carboxymethyl cellulose to the precursor material is 5:100.

[0084] Example 2

[0085] The present example provides a vehicle active carbon, and the preparation method of the vehicle active carbon is only different from that of Example 1 in that:

[0086] In the present example, the aqueous solution of the alkali metal complex salt in step (1) is modified to an aqueous solution of NaCl and Na2B4O7 with a metal ion concentration of 5wt% (Cl / B = 1:6.25).

[0087] Example 3

[0088] The present example provides a vehicle active carbon, and the preparation method of the vehicle active carbon is only different from that of Example 1 in that:

[0089] In the present example, the aqueous solution of the alkali metal complex salt in step (1) is modified to an aqueous solution of NaH2PO4 and Na2B4O7 with a metal ion concentration of 5wt% (P / B = 1:2).

[0090] Example 4

[0091] The present example provides a vehicle active carbon, and the preparation method of the vehicle active carbon is only different from that of Example 1 in that:

[0092] In the present example, the aqueous solution of the alkali metal complex salt in step (1) is modified to an aqueous solution of NaCl, NaH2PO4 and Na2B4O7 with a metal ion concentration of 5wt% (Cl / (P+B) = 1:10).

[0093] Example 5

[0094] The present example provides a vehicle active carbon, and the preparation method of the vehicle active carbon comprises the following steps:

[0095] (1) 1000g of coconut shell active carbon with a particle size of 1mm (specific surface area 600m 2 / g, pore volume 0.29cm 3 / g, micropore volume 0.27cm 3 / g, mesopore volume 0.02cm 3 / g) after physical activation is mixed in an aqueous solution of NaCl, NaH2PO4 and Na2B4O7 with a metal ion concentration of 5wt% (Cl / (P+B) = 1:10) for 2 hours, filtered, dried, and then subjected to fluidized bed activation treatment under water vapor to obtain a precursor material;

[0096] The flow rate of the water vapor is the minimum fluidization velocity of the fluidized bed; the activation temperature is 850°C, and the residence time is 15 min; the silica sand is supplemented in the fluidized bed during the fluidized bed activation treatment; and the mass ratio of the silica sand to the raw material is 1:3.5.

[0097] (2) washing the precursor material obtained in step (1), and then sequentially performing a first drying treatment, crushing, extrusion molding, and a second drying treatment to obtain cylindrical granular activated carbon for vehicles with a diameter of 2.0 mm;

[0098] The washing includes acid washing and water washing performed sequentially; the acid washing is continuous washing at 80°C for 30 min using 3wt% hydrochloric acid; and the water washing is repeated washing at 100°C for 20 h using deionized water until the pH value of the washing liquid is 7;

[0099] The temperature of the first drying treatment is 200°C;

[0100] Carboxymethyl cellulose is supplemented in the extrusion molding; and the mass ratio of the carboxymethyl cellulose to the precursor material is 5:100.

[0101] Example 6

[0102] This example provides an activated carbon for vehicles, and the preparation method of the activated carbon for vehicles is different from that of Example 1 only in that:

[0103] In this example, the activation temperature in step (1) is modified to 800°C.

[0104] Example 7

[0105] This example provides an activated carbon for vehicles, and the preparation method of the activated carbon for vehicles is different from that of Example 1 only in that:

[0106] In this example, the activation temperature in step (1) is modified to 1100°C.

[0107] Example 8

[0108] This example provides an activated carbon for vehicles, and the preparation method of the activated carbon for vehicles is different from that of Example 1 only in that:

[0109] In this example, the activation temperature in step (1) is modified to 1200°C.

[0110] Comparative Example 1

[0111] This comparative example provides an activated carbon for vehicles, and the preparation method of the activated carbon for vehicles is different from that of Example 1 only in that:

[0112] The comparative example omits the process of mixing the aqueous alkali metal composite salt solution described in step (1).

[0113] Comparative Example 2

[0114] The comparative example provides a vehicle active carbon, the preparation method of which is only different from that of Example 1 in that:

[0115] The comparative example modifies the aqueous alkali metal composite salt solution described in step (1) to an aqueous NaCl solution with a metal ion concentration of 5 wt%.

[0116] Comparative Example 3

[0117] The comparative example provides a vehicle active carbon, the preparation method of which is only different from that of Example 1 in that:

[0118] The comparative example modifies the aqueous alkali metal composite salt solution described in step (1) to an aqueous NaH2PO4 solution with a metal ion concentration of 5 wt%.

[0119] Comparative Example 4

[0120] The comparative example provides a vehicle active carbon, the preparation method of which is only different from that of Example 1 in that:

[0121] The comparative example modifies the aqueous alkali metal composite salt solution described in step (1) to an aqueous Na2B4O7 solution with a metal ion concentration of 5 wt%.

[0122] Comparative Example 5

[0123] The comparative example provides a vehicle active carbon, the preparation method of which is only different from that of Example 1 in that:

[0124] The comparative example modifies the fluidized bed activation treatment described in step (1) to a fixed bed activation treatment; and modifies the activation time to 4.5 h and the activation temperature to 950°C.

[0125] Comparative Example 6

[0126] The comparative example provides a vehicle active carbon, the preparation method of which is only different from that of Example 5 in that:

[0127] The comparative example modifies the fluidized bed activation treatment described in step (1) to a fixed bed activation treatment; and modifies the activation time to 5 h and the activation temperature to 900°C.

[0128] Performance detection:

[0129] The vehicle active carbons provided by the above examples and comparative examples are subjected to performance detection (specific surface area, pore volume, butane working capacity BWC, flushing rate, and strength) and yield, and the results are shown in Table 1.

[0130] Wherein, the pore with diameter < 2nm is micropore, the pore with diameter 2-50nm is mesopore, and the pore with diameter > 50nm is macropore;

[0131] The specific surface area is calculated by obtaining nitrogen adsorption isotherm at the boiling point of liquid nitrogen, and then calculating the specific surface area by BET method;

[0132] The pore volume is calculated by cumulative pore volume in density function theory;

[0133] The butane working capacity BWC and the flushing rate are obtained according to GB / T 20449-2006 Test method for butane working capacity of activated carbon;

[0134] The strength test method is obtained according to GBT 12496.6-1999 Test method for strength of wood-based activated carbon;

[0135] The yield is the ratio of the mass of the sample after fluidized bed activation to the mass of the sample before activation.

[0136] Table 1

[0137]

[0138]

[0139] The following points can be known from analyzing Table 1:

[0140] (1) Examples 1-4 are all samples prepared by fluidized bed using composite salt, and NaCl-NaH2PO4, NaCl-Na2B4O7, NaH2PO4-Na2B4O7, NaCl-NaH2PO4-Na2B4O7 composite salt are used in turn. The raw materials and preparation methods of Comparative Examples 2-4 are the same as those of Examples 1-4, and the difference lies in that NaCl, NaH2PO4 and Na2B4O7 salt are used alone in turn.

[0141] According to the above comparative experiments, it can be known that the alkali metal composite salt has a synergistic effect, not only the reaction activity is improved to expand the specific surface area and pore volume, but also the ability to form mesopore is strengthened, so that the mesopore ratio in the sample is significantly improved, and the butane working capacity and the flushing rate are significantly improved;

[0142] (2) The raw material and composite salt of Comparative Example 5 are the same as those of Example 1 using the NaCl-NaH2PO4 system for CO2 activation, except that a fixed bed is used for activation. By controlling the yield, the sample obtained by the fixed bed activation is equivalent to the sample obtained by the fluidized bed activation in terms of pore performance indicators and butane working capacity and flushing performance. However, compared with Example 1 using the fluidized bed, the sample obtained by the fixed bed does not have the process of the fluidized bed strengthening the diffusion of the composite molten salt, thereby promoting the more uniform distribution of the molten salt. Therefore, the sample obtained by the fixed bed needs to be activated at a higher activation temperature (950℃) and for a longer activation time (4.5 hours) to be equivalent to the sample obtained by the fluidized bed. Therefore, the fluidized bed activation process provided by the present application not only reduces the activation temperature, but also shortens the reaction time.

[0143] (3) The raw material and composite salt of Comparative Example 6 are the same as those of Example 5 using the NaCl-Na2B4O7 system for steam activation, except that a fixed bed is used for activation. By controlling the yield, the sample obtained by the fixed bed activation is equivalent to the sample obtained by the fluidized bed activation in terms of pore performance indicators and butane working capacity and flushing performance. However, compared with Example 5 using the fluidized bed, the sample obtained by the fixed bed does not have the process of the fluidized bed strengthening the diffusion of the composite molten salt, thereby promoting the more uniform distribution of the molten salt. Therefore, the sample obtained by the fixed bed needs to be activated at a higher activation temperature (900℃) and for a longer activation time (5 hours) to be equivalent to the sample obtained by the fluidized bed.

[0144] (4) The activation temperature of Example 6 is 800℃, which is lower than the lower limit of the activation temperature range 850-1100℃. At a low activation temperature, on the one hand, the reaction rate is reduced, and on the other hand, the composite salt cannot form a molten salt completely at this temperature, which promotes the more uniform distribution of the molten salt, thereby resulting in insufficient activation degree and making the performance of the activated carbon not up to standard. The activation temperature of Example 7 is 1100℃, which is within the activation temperature range 850-1100℃, and the performance is up to standard. The activation temperature of Example 8 is 1200℃, which exceeds the upper limit of the activation temperature range 850-1100℃. At a high activation temperature, the sample is sintered, and the specific surface area, total pore volume and mesopore volume are all significantly reduced, thereby making the performance of the activated carbon not up to standard.

[0145] The applicant declares that the detailed process equipment and process flow of the present application are illustrated by the above examples, but the present application is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present application must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any improvement on the present application, equivalent replacement of each raw material of the product of the present application and addition of auxiliary ingredients, selection of specific modes, etc. all fall within the protection scope and disclosure scope of the present application.

Claims

1. An activated carbon for use in a vehicle, characterized by comprising a plurality of pores having a diameter of 0.5 to 2 nm. The preparation raw material of the vehicle active carbon comprises a base material after physical activation and an alkali metal composite salt; The alkali metal composite salt comprises a combination of any two or three of an alkali metal chloride salt, an alkali metal phosphorus salt or an alkali metal boron salt; The mass ratio of metal ions to the base material in the vehicle active carbon is (0.5-5):100; The preparation method of the vehicle active carbon is prepared by the following method, which comprises the following steps: (1) mixing the base material after physical activation and an alkali metal composite salt aqueous solution according to the formula amount, and then performing fluidized bed activation treatment to obtain a precursor material; (2) washing the precursor material obtained in step (1), and then sequentially performing primary drying treatment, crushing, extrusion molding and secondary drying treatment to obtain the vehicle active carbon.

2. The activated carbon for vehicles according to claim 1, characterized by When the alkali metal composite salt is a mixture of an alkali metal chloride salt and an alkali metal boron salt, the molar ratio of chlorine element to boron element is 1:(4-28).

3. The activated carbon for vehicles according to claim 1, characterized by When the alkali metal composite salt is a mixture of an alkali metal chloride salt, an alkali metal phosphorus salt and an alkali metal boron salt, the molar ratio of chlorine element to the sum of boron element and phosphorus element is Cl:(P+B) 1:(5-35).

4. The activated carbon for vehicles according to claim 1, wherein When the alkali metal composite salt is a mixture of an alkali metal phosphorus salt and an alkali metal boron salt, the molar ratio of phosphorus element to boron element is 1:(1-4).

5. The activated carbon for vehicles according to claim 1, wherein When the alkali metal composite salt is a mixture of an alkali metal chloride salt and an alkali metal phosphorus salt, the molar ratio of chlorine element to phosphorus element is 1:(1-7).

6. The activated carbon for vehicles according to claim 1, wherein The base material comprises any one or a combination of at least two of plant materials, mineral materials, natural raw materials or synthetic materials.

7. The activated carbon for vehicles according to claim 1, wherein The particle size of the base material is 0.05-3.00 mm.

8. The activated carbon for vehicles according to claim 1, wherein The specific surface area of the base material is 20-1000 m 2 / g.

9. The activated carbon for vehicles according to claim 8, wherein The specific surface area of the base material is 600-1000 m 2 / g.

10. A method of producing the activated carbon for vehicle as claimed in any one of claims 1 to 9, characterized by, The preparation method comprises the following steps: (1) mixing the base material after physical activation and an alkali metal composite salt aqueous solution according to the formula amount, and then performing fluidized bed activation treatment to obtain a precursor material; (2) washing the precursor material obtained in step (1), and then sequentially performing primary drying treatment, crushing, extrusion molding and secondary drying treatment to obtain the vehicle active carbon.

11. The method of claim 10, wherein, The activation gas used in the fluidized bed activation treatment in step (1) comprises carbon dioxide and / or water vapor.

12. The method of claim 10, wherein, The flow rate of the activation gas used in the fluidized bed activation treatment in step (1) is 1-5 times the minimum fluidization velocity of the fluidized bed.

13. The method of claim 10, wherein, The activation temperature of the fluidized bed activation treatment in step (1) is 850-1100°C.

14. The method of claim 10, wherein, The residence time of the fluidized bed activation treatment in step (1) is 5-30 min.

15. The preparation method according to claim 10, characterized in that, Inert particles are supplemented in the fluidized bed in the fluidized bed activation treatment in step (1).

16. The method of claim 15, wherein, The inert particles comprise any one or a combination of at least two of river sand, silica sand or dolomite.

17. The preparation method according to claim 15, characterized in that, The mass ratio of the inert particles to the preparation raw material is >1:

4.

18. The method of claim 10, wherein, The washing in step (2) comprises acid washing and water washing sequentially.

19. The method of claim 18, wherein, The washing liquid used in the acid washing comprises hydrochloric acid, and the mass concentration of the hydrochloric acid is 0.1-15 wt%.

20. The method of claim 18, wherein, The time of the acid washing is 10 min-24 h.

21. The method of claim 18, wherein, The temperature of the acid washing is 10-80°C.

22. The preparation method according to claim 18, characterized in that, The temperature of the water washing is 10-120°C.

23. The preparation method according to claim 18, characterized in that, The time of the water washing is 1-24 h.

24. The method of claim 10, wherein, The end point of the washing is that the pH of the washing liquid is neutral.

25. The method of claim 10, wherein, The temperature of the first drying treatment is 80-200℃.

26. The method of claim 10, wherein, The extrusion forming in step (2) is supplemented with a binder.

27. The method of claim 26, wherein, The binder includes any one or a combination of at least two of a cellulose binder, a bentonite binder or a resin binder.

28. The method of claim 26, wherein, The mass ratio of the binder to the precursor material is (1-20):

100.

29. The preparation method according to claim 27, characterized in that, The cellulose binder includes any one or a combination of at least two of carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose or hydroxyethyl methyl cellulose.

30. The preparation method according to claim 27, characterized in that, The bentonite binder includes any one or a combination of at least two of bentonite, white clay or knot clay.

31. The preparation method according to claim 27, characterized in that, The resin binder includes phenolic resin and / or polyvinyl alcohol.

32. The method of claim 10, wherein, The extrusion forming in step (2) is further supplemented with water.

33. The method of claim 32, wherein the method is performed in a single step. The mass ratio of the water to the precursor material is (10-250):

100.

34. The method of claim 10, wherein, The extrusion forming obtains cylindrical granules.

35. The method of claim 34, wherein the method further comprises, The diameter of the cylindrical granules is 1.5-2.5 mm.

36. The method of claim 10, wherein, The preparation method includes the following steps: (1) mixing the physically activated matrix material and the aqueous solution of the alkali metal composite salt according to the formula amount, and then performing fluidized bed activation treatment under an activation gas to obtain a precursor material; wherein the flow rate of the activation gas is 1-5 times the minimum fluidization velocity of the fluidized bed; the activation temperature is 850-1100℃, and the residence time is 5-30 min; inert particles are supplemented in the fluidized bed during the fluidized bed activation treatment; the mass ratio of the inert particles to the preparation raw material is >1:4; (2) washing the precursor material obtained in step (1), and then sequentially performing first drying treatment, crushing, extrusion forming and second drying treatment to obtain cylindrical granules of 1.5-2.5 mm in diameter for vehicle active carbon; wherein the washing includes sequential acid washing and water washing; the acid washing is washing with 0.1-15wt% hydrochloric acid at 10-80℃ for 10 min-24 h; the water washing is washing with deionized water at 10-120℃ for 1-24 h; The temperature of the first drying treatment is 80-200℃. The extrusion forming in step (2) is supplemented with a binder; the mass ratio of the binder to the precursor material is (1-20):100.

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