Activated carbon for vehicle and method for producing the same

Abstract

The application provides a vehicle active carbon, raw materials for preparing the vehicle active carbon include high-carbon substance and alkali metal composite salt; the high-carbon substance has a carbon content of greater than or equal to 80%; the alkali metal composite salt includes a combination of any two or three of alkali metal chloride salt, alkali metal phosphorus salt and alkali metal boron salt; and the mass ratio of metal ions to high-carbon substance in the vehicle active carbon is (0.5-5):100. The preparation method includes: combining the high-carbon substance and the alkali metal composite salt, then physically activating, and then cleaning and forming to obtain the vehicle active carbon. Through compounding different functional alkali metal salts and controlling the activation process, the specific surface area, pore volume and pore size distribution of the active carbon can be designed in a targeted manner, so that the performance requirements of the vehicle carbon are met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of activated carbon, and relates to an activated carbon for a vehicle carbon canister, in particular to a vehicle activated carbon and a preparation method. BACKGROUND

[0002] Gasoline is a volatile fuel. When a vehicle is running or being turned off, the fuel in the fuel tank is quickly volatilized to increase the pressure inside the fuel tank. When the pressure reaches a certain value, certain danger will be caused. Therefore, people try to balance the pressure. Initially, the fuel tank cap is made into a pressure-limiting valve. When the pressure is higher than a certain value, the pressure-limiting valve is opened to discharge the gasoline vapor into the atmosphere. Later, a carbon canister is arranged for the purpose of saving fuel and protecting the environment. The carbon canister is generally arranged between the fuel tank and the engine. The carbon canister is filled with activated carbon with strong adsorption. The excess fuel vapor in the fuel tank is no longer discharged into the atmosphere, but is introduced into the activated carbon canister through a pipe, and the fuel vapor is adsorbed by the activated carbon. When the vehicle is started, the activated carbon canister electromagnetic valve is opened in time to re-charge the adsorbed fuel vapor into the intake pipe, so as to achieve the purposes of saving fuel and environmental protection.

[0003] The vehicle carbon canister utilizes the adsorption and desorption characteristics of activated carbon to adsorb the vapor generated by the fuel system in the activated carbon canister, so as to prevent the fuel system from being directly discharged into the atmosphere due to the breathing effect. The fuel vapor in the activated carbon canister is desorbed and introduced into the engine cylinder through the vacuum degree at the engine intake manifold to participate in combustion, so as to be controlled and regenerated. The vehicle activated carbon is required to have a high proportion of mesopores with a diameter of 2-5 nm, so as to facilitate the adsorption and desorption of oil gas.

[0004] US8759253B2 discloses a preparation method of a conventional vehicle activated carbon. Sawdust and fruit shells / nuts are used as raw materials, and phosphoric acid is used as an activator. After mixing, carbonization and activation, the vehicle activated carbon is prepared. Patent US5039651 uses rice husk with high cellulose content as raw material, and zinc chloride as activator to prepare the vehicle activated carbon. CN 1815007A discloses a method for preparing vehicle activated carbon by a physical method. Specifically, it is disclosed that the vehicle activated carbon is prepared by using anthracite with 70% carbon and less than 4% ash content as raw material, and by twice high-temperature activation in a mixed gas of 10% carbon dioxide, 70% nitrogen and 20% water vapor for 30-50 hours. However, the methods disclosed in US8759253B2 and US5039651 both use biomass as raw material, and the supply of raw material is easily limited. In addition, the activation time in CN 1815007A is too long by the pure physical method, which causes waste of resources and is not conducive to industrial production.

[0005] The British research group's papers (Carbon, 1987, 25, 4: 559-563; Carbon Vol. 25. No. 4. pp. 565-568, 1987; Carbon Vol 26, No. 1 pp. 7-11. 1988; Carbon, 1992, 30, 6: 907-911) disclose a method for preparing microporous / mesoporous activated carbon fibers with viscose fibers as raw materials, and phosphoric acid, boric acid, phosphate, borate and alkali metal chloride as activators, through carbonization and activation steps. However, the principle of this method is that a large number of hydroxyl groups in viscose fibers undergo cellulose depolymerization, hydrolysis / dehydration, formation of aromatic ring structure and oxidative pyrolysis processes under the action of activators. The interaction between hydroxyl groups in raw materials and alkali metal ions is controlled by the [Na+] / [B] and [Na+] / [P] ratios, i.e. the pH value, thereby affecting the reaction activity, the products in the hydrolysis / dehydration / aromatization process and the degree of boron / phosphorus oxide polymerization to form glassy substances. The above three points jointly determine the development of mesopores in activated carbon fibers. That is, the reaction principle of this method is complex, there are many limiting factors, and it is not conducive to large-scale production.

[0006] Therefore, it is necessary to provide a preparation method of vehicle activated carbon which has simple preparation method and wide selection range of raw materials. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a vehicle activated carbon and a preparation method. The preparation method can realize the directional design of the specific surface area, pore volume and pore size distribution of the activated carbon by compounding and activating process control of different functional alkali metal salts, so as to meet the performance requirements of vehicle activated carbon.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a vehicle activated carbon, and the preparation raw materials of the vehicle activated carbon include high-carbon substances and alkali metal complex salt.

[0010] The carbon content of the high-carbon substance is ≥80%, for example, it can be 80%, 82%, 84%, 86%, 88%, 90%, 94% or 98%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0011] The alkali metal complex salt includes a combination of any two or three of alkali metal chloride, alkali metal phosphate and alkali metal borate. Typical but non-limiting combinations include a combination of alkali metal chloride and alkali metal phosphate, a combination of alkali metal phosphate and alkali metal borate, a combination of alkali metal chloride and alkali metal borate, or a combination of alkali metal chloride, alkali metal phosphate and alkali metal borate.

[0012] The mass ratio of metal ions to high-carbon substances in the activated carbon for vehicles 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 in the value range are also applicable.

[0013] The specific surface area of the activated carbon for vehicles provided by the 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%.

[0014] As a preferred technical solution of the 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 in the value range are also applicable.

[0015] 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 in the value range are also applicable.

[0016] Preferably, when the alkali metal composite salt is a mixture of alkali metal phosphorus salt and alkali metal boron salt, the molar ratio of phosphorus element to boron element is 1:(1-4), for example, it can be 1:1, 1:2, 1:3 or 1:4, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] Preferably, when the alkali metal composite salt is a mixture of alkali metal chloride salt and alkali metal phosphorus salt, the molar ratio of chlorine element to phosphorus element is 1:(1-7), for example, it 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.

[0018] It is worth mentioning that the alkali metal chlorides, alkali metal phosphates and alkali metal borates in the alkali metal composite salt have a synergistic effect. First, the combination type can be selected according to the design requirements of the BWC. The activity of the BWC and the alkali metal composite salt in catalyzing carbon dioxide / water vapor is positively correlated, and the catalytic activity ranking is: alkali metal chlorides and borate composite salt > chlorides, phosphates and borate composite salt > phosphates and borate composite salt > chlorides and phosphates composite salt; 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 application selects the above ratio, if the ratio is too low, it will lead to insufficient catalytic activity of the vehicle active carbon, if the ratio is too high, it will lead to insufficient mesopore ratio in the vehicle active carbon.

[0019] It is worth mentioning that the alkali metal chlorides in the application include sodium chloride and / or potassium chloride.

[0020] 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 orthophosphates and their acid salts and / or potassium orthophosphates and their acid salts.

[0021] 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.

[0022] As a preferred technical solution of the application, the high-carbon substance includes a base material or active carbon.

[0023] Preferably, the base material includes a mineral raw material and / or a carbonized substance.

[0024] Preferably, the mineral raw material includes any one or a combination of at least two of the bituminous coal, anthracite, petroleum coke or pitch, and a typical but non-limiting combination includes: a combination of bituminous coal and anthracite, a combination of petroleum coke and pitch, a combination of bituminous coal, anthracite and petroleum coke, a combination of anthracite, petroleum coke and pitch, or a combination of bituminous coal, anthracite, petroleum coke and pitch.

[0025] Preferably, the carbonized substance includes any one or a combination of at least two of the plant, mineral, natural raw material or synthetic material.

[0026] Preferably, the specific surface area of the active carbon is 20-1000m 2 / g, for example, it can be 20m 2 / g, 100m 2 / g, 300m 2 / g, 500m 2 / g, 700m 2 / g or 1000 m 2 / g, but not limited to the listed values, other values within the range are also applicable; preferably 600-1000 m 2 / g.

[0027] The specific surface area of the activated carbon in the present application is 20-1000 m 2 / g, the greater the specific surface area, the more the activator can be dispersed and attached to the surface and pores of the activated carbon, thereby reducing the amount of activator used.

[0028] Preferably, the particle size of the activated carbon is 0.05-6.00 mm, for example, it can be 0.05 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or 6 mm, but not limited to the listed values, other values within the range are also applicable; preferably 1.00-3.00 mm.

[0029] The particle size of the activated carbon in the present application is 0.05-6.00 mm, if the particle size is too fine, it may escape from the reaction device due to air flow during the subsequent activation process; if the particle size is too coarse, the activator cannot fully enter and adhere to the pores of the activated carbon during the contact between the raw material and the activator.

[0030] It is worth noting that the activated carbon described in the present application is the activation product of plant, mineral, natural raw material and synthetic material. Specifically, the plant-based activated carbon includes carbonaceous raw materials, such as wood, coconut shell and other nut shell raw materials; mineral raw materials include coal, pitch, coke or petroleum coke; natural raw materials include natural fibers such as hemp and cotton, regenerated fibers such as rayon and viscose rayon, semi-synthetic fibers such as acetate and triacetate; synthetic materials include polyacrylonitrile, phenolic resin, polyvinylidene chloride, polycarbonate and polyvinyl alcohol.

[0031] In a second aspect, the present application provides a preparation method of the activated carbon for vehicles as provided in the first aspect, which comprises Scheme A and / or Scheme B.

[0032] The Scheme A comprises: mixing the activated carbon and the alkali metal composite salt according to the formula amount, and then sequentially performing physical activation treatment, cleaning, drying, crushing and extrusion molding to obtain the activated carbon for vehicles;

[0033] The Scheme B comprises: crushing after drying the base material, mixing the alkali metal composite salt according to the formula amount and then performing extrusion molding; and then sequentially performing pre-oxidation, carbonization, physical activation treatment, cleaning and drying to obtain the activated carbon for vehicles.

[0034] The preparation method provided by the present application takes high-carbon substances as raw materials, thereby widening the selection range of raw materials; by using different functional alkali metal salts to produce a synergistic effect, the reactivity is improved, thereby being more conducive to expanding the pores and increasing the capacity while producing more mesopores, so as to meet the performance requirements of vehicle carbon; and the problem that the pore performance cannot meet the performance requirements of vehicle carbon due to the insufficient reactivity or mesopores of a single variety of salt is overcome.

[0035] The functionality of the alkali metal composite salt described in the present application includes: in the physical activation process, carbon dioxide and water vapor are main activation agents, and the high-carbon raw material undergoes oxidation pyrolysis in the carbon dioxide and water vapor activation and a pore etching 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: alkali metal borate salt>alkali metal chloride salt>alkali metal phosphate salt, and the mesopore forming ability is ranked as: alkali metal phosphate salt>alkali metal borate salt>alkali metal chloride salt. When any one of the alkali metal salts is used alone, the activation ability and the mesopore forming ability are weak, which leads to that the pore performance of the activated carbon prepared cannot meet the performance requirements of vehicle carbon.

[0036] It is worth noting that the mixing described in the scheme A provided by the present application is not limited to the mixing method, as long as the activated carbon contains the alkali metal composite salt. The mixing method can be: a method of spraying an aqueous solution of the alkali metal composite salt while mixing the activated carbon, a method of immersing the raw material in the aqueous solution of the composite salt, etc. Through the contact, the composite salt is attached to the surface or the pore of the activated carbon.

[0037] The mixing method described in the scheme B of the present application can be mixing the base material and the aqueous solution of the alkali metal composite salt, or adding water after mixing the base material and the solid powder of the alkali metal composite salt.

[0038] In the scheme A provided by the present application, the mixture needs to be further mixed with 1-20 parts by weight of a binder during the extrusion molding process; in order to adjust the hardness of the obtained molded product, water can also be mixed.

[0039] Preferably, the binder includes any one or a combination of at least two of a cellulose-based binder, a bentonite-based binder or a resin-based binder, and a typical but non-limiting combination includes a combination of a cellulose-based binder and a bentonite-based binder, a combination of a bentonite-based binder and a resin-based binder, a combination of a cellulose-based binder and a resin-based binder, or a combination of a cellulose-based binder, a bentonite-based binder and a resin-based binder.

[0040] Preferably, the cellulose-based binder includes any one or a combination of at least two of carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose or hydroxyethyl methyl cellulose.

[0041] Preferably, the said bentonite-based binder includes any one or a combination of at least two of bentonite, white clay or knot clay.

[0042] Preferably, the said resin-based binder includes phenol formaldehyde resin and / or polyvinyl alcohol.

[0043] It is worth mentioning that the said extrusion process of scheme B further includes mixing 10-50 parts by weight of a binder.

[0044] Preferably, the binder used in scheme B includes a mineral-based raw material, preferably tar and / or pitch similar to the structural properties of charcoal and activated charcoal.

[0045] Preferably, when pitch is selected as the binder in scheme B, a binding auxiliary component is further mixed, the said binding auxiliary component includes castor oil and / or lubricating oil.

[0046] Preferably, scheme B further includes mixing an auxiliary reinforcing agent to further improve the strength of the finished product; the said auxiliary reinforcing agent includes any one or a combination of at least two of lignin, sodium lignosulfonate or calcium lignosulfonate, and a typical but non-limiting combination includes a combination of lignin and sodium lignosulfonate, a combination of lignin and calcium lignosulfonate, a combination of sodium lignosulfonate and calcium lignosulfonate, or a combination of lignin, sodium lignosulfonate and calcium lignosulfonate.

[0047] As a preferred technical solution of the present application, the activation gas used in the said physical activation process includes carbon dioxide and / or water vapor.

[0048] Preferably, the mass-based flow flux of the said carbon dioxide is 100-1500 L / h.kg, for example, it can be 100 L / h.kg, 400 L / h.kg, 800 L / h.kg, 1200 L / h.kg, 1400 L / h.kg or 1500 L / h.kg, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0049] Preferably, the mass-based flow flux of the said water vapor is 0.05-1 L / h.kg, for example, it can be 0.05 L / h.kg, 0.1 L / h.kg, 0.3 L / h.kg, 0.5 L / h.kg, 0.7 L / h.kg, 0.9 L / h.kg or 1 L / h.kg, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0050] The mass-based flux of carbon dioxide and / or water vapor in the present application is calculated as pure gaseous carbon dioxide or water under activation conditions and based on the amount of starting material to be used with the activation gas; below the lower flux limit, the reaction activity is low, resulting in low total pore volume and mesopore rate, and above the upper flux limit, the phosphorus / boron oxide absorbs excess oxygen to form too many large pores in the process of polymerization to form mesopores.

[0051] Preferably, the time of the physical activation treatment is 2.5-8h, for example, it can be 2.5h, 3h, 4h, 5h, 6h, 7h or 8h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0052] Preferably, the temperature of the physical activation treatment is 900-1100℃, for example, it can be 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.

[0053] The temperature of the physical activation treatment in the present application is relatively high, which aims to prevent the phosphorus / boron oxide from polymerizing to form too many large pores.

[0054] As a preferred technical solution of the present application, the cleaning includes acid pickling and water washing in sequence.

[0055] Preferably, the acid solution used in the acid pickling includes hydrochloric acid.

[0056] Preferably, the concentration of the hydrochloric acid is 0.1-15wt%, for example, it can be 0.1wt%, 1wt%, 3wt%, 5wt%, 7wt%, 9wt%, 11wt%, 13wt% or 15wt%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0057] Preferably, the time of the acid pickling is 10min-24h, for example, it can be 10min, 30min, 1h, 3h, 5h, 9h, 12h, 15h, 18h, 20h, 22h or 24h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0058] Preferably, the temperature of the acid pickling 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.

[0059] It is worth noting that the acid pickling process in the present application can be intermittent acid pickling or continuous acid pickling. For example, the intermittent acid pickling is 10min of acid pickling each time, and the acid pickling is repeated 3 times.

[0060] Preferably, the water washing time is 1-24h, for example, it can be 1h, 3h, 5h, 9h, 12h, 15h, 18h, 20h, 22h or 24h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0061] Preferably, the water washing temperature is 10-120℃, for example, it can be 10℃, 30℃, 50℃, 70℃, 90℃ or 120℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0062] Preferably, the drying temperature 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.

[0063] As a preferred technical solution of the present application, the average particle size of the pulverized base material in solution B is 2-100μm, for example, it can be 2μm, 10μm, 20μm, 40μm, 60μm, 80μm or 100μm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0064] Preferably, the pre-oxidation temperature in solution B is 200-400℃, for example, it can be 200℃, 240℃, 280℃, 320℃, 360℃ or 400℃, but is not limited to the listed values, and other values not listed in the value range are also applicable; preferably, it is 220-300℃.

[0065] Preferably, the pre-oxidation time in solution B is 0.5-20h, for example, it can be 0.5h, 1h, 3h, 5h, 9h, 12h, 15h, 18h or 20h, but is not limited to the listed values, and other values not listed in the value range are also applicable; preferably, it is 1-8h.

[0066] The pre-oxidation in the present application is a process of oxidizing the raw material at low temperature, and the pitch in the binder changes from thermoplasticity to thermosetting, so that the shaped object can still maintain high mechanical strength after the subsequent activation process.

[0067] As a preferred technical solution of the present application, the carbonization temperature in solution B is 300-900℃, preferably 300-600℃.

[0068] Preferably, the carbonization time of the scheme B is 0.5-20h, for example, it can be 0.5h, 1h, 3h, 5h, 9h, 12h, 15h, 18h or 20h, but is not limited to the listed values, and other values not listed in the value range are also applicable; preferably, it is 1-10h.

[0069] As a preferred technical solution of the present application, the extrusion molding obtains cylindrical granules with a diameter of 1.5-2.5mm, for example, it can be 1.5mm, 1.7mm, 1.9mm, 2.1mm, 2.3mm or 2.5mm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0070] Preferably, the water content of the vehicle active carbon is <5%, for example, it can be 4.8%, 4.6%, 4.4%, 4%, 3%, 2% or 1%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0071] As a preferred technical solution of the present application, the preparation method of the vehicle active carbon provided in the second aspect of the present application comprises scheme A and / or scheme B.

[0072] The scheme A comprises: mixing the active carbon and the alkali metal composite salt according to the formula amount, then performing physical activation treatment at 900-1100℃ for 2.5-8h using an activation gas, then performing acid pickling at 10-80℃ for 10min-24h using hydrochloric acid with a concentration of 0.1-15wt%, then performing water washing at 10-120℃ for 1-24h, then drying at 80-200℃, then performing crushing and extrusion molding to obtain the vehicle active carbon with a water content of <5%;

[0073] The scheme B comprises: drying the base material, then crushing to an average particle size of 2-100μm, then mixing the alkali metal composite salt according to the formula amount, then performing extrusion molding; then performing pre-oxidation at 200-400℃ for 0.5-20h, then performing carbonization at 300-900℃ for 0.5-20h, then performing physical activation treatment at 900-1100℃ for 2.5-8h using an activation gas, then performing acid pickling at 10-80℃ for 10min-24h using hydrochloric acid with a concentration of 0.1-15wt%, then performing water washing at 10-120℃ for 1-24h, then drying at 80-200℃ to obtain the vehicle active carbon with a water content of <5%.

[0074] 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.

[0075] Compared with the prior art, the present application has the following beneficial effects:

[0076] (1) The vehicle active carbon provided by the present application meets the performance requirements of vehicle carbon, and has a specific surface area of more than 1200 m 2 / g, a pore volume of more than 1 cm 3 / g, a mesopore volume of more than 0.5 cm 3 / g, a butane working capacity (BWC) of more than 10 g / 100 ml, and a strength of more than 85%.

[0077] (2) The preparation method of the vehicle active carbon provided by the present application uses high-carbon substances as raw materials, thereby widening the selection range of raw materials.

[0078] (3) The preparation method of the vehicle active carbon provided by the present application uses different functional alkali metal salts to produce a synergistic effect, thereby improving the reaction activity, and more favorably producing more mesopores while expanding the pores and increasing the volume, so as to meet the performance requirements of vehicle carbon.

[0079] (4) The preparation method of the vehicle active carbon provided by the present application overcomes the problem that a single variety of salt cannot meet the performance requirements of vehicle carbon due to insufficient reaction activity or mesopores. DETAILED DESCRIPTION

[0080] In order to facilitate the understanding of the present application, the present 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 present application, and should not be regarded as a specific limitation on the present application.

[0081] Example 1

[0082] The present example provides a vehicle active carbon, and the preparation method of the vehicle active carbon comprises the following steps:

[0083] 1000 g of coconut shell active carbon (specific surface area 600 m 2 / g, pore volume 0.29 cm 3 / g, micropore volume 0.27 cm 3 / g, mesopore volume 0.02 cm 3 / g) with a particle size of 1 mm is impregnated in a NaCl and NaH2PO4 aqueous solution (Cl / P=1:1.3) with a metal ion concentration of 5 wt% for 2 hours, and then filtered and dried to obtain a mixed sample.

[0084] After the mixed sample is physically activated at 950℃ for 4.5 hours under a carbon dioxide gas with a mass-based flow rate of 200 L / h.kg, the sample is continuously acid-washed at 80℃ for 30 min using 3% hydrochloric acid, and then repeatedly washed with deionized water at 100℃ for 1 h until the pH value of the washing liquid is close to 7, and the sample is dried at 200℃ and then crushed to obtain a crushed powder.

[0085] The pulverized powder and 5wt% of sodium carboxymethyl cellulose are mixed, and after the mixing is completed, the pellets are formed by extrusion to obtain the active carbon for vehicles with water content <5%.

[0086] Example 2

[0087] The present example provides an active carbon for vehicles, and a preparation method of the active carbon for vehicles comprises the following steps:

[0088] 1000g of coconut shell active carbon (specific surface area 600m 2 / g, pore volume 0.29cm 3 / g, micropore volume 0.27cm 3 / g, mesopore volume 0.02cm 3 / g) with a particle size of 1mm is immersed in a NaCl and Na2B4O7 aqueous solution (Cl / B=1:6.25) with a metal ion concentration of 5wt% for 2 hours, and then filtered and dried to obtain a mixed sample;

[0089] The mixed sample is physically activated at 950°C for 4.5 hours in carbon dioxide gas with a mass-based flow rate of 200L / h.kg. The active carbon powder is intermittently acid washed at 80°C for 30min using 3% hydrochloric acid (10min for each acid washing, and the acid washing is repeated 3 times), and then repeatedly washed with deionized water at 100°C for 1h until the pH value of the washing liquid is close to 7. After drying at 180°C, the active carbon powder is pulverized into powder to obtain a pulverized powder;

[0090] The active carbon powder and 5% of sodium carboxymethyl cellulose based on the mass of the powder are mixed, and after the mixing is completed, the pellets are formed by extrusion to obtain the active carbon for vehicles with water content <5%.

[0091] Example 3

[0092] The present example provides an active carbon for vehicles, and a preparation method of the active carbon for vehicles is different from that of Example 1 only in that:

[0093] In the present example, the alkali metal composite salt is modified to a NaH2PO4 and Na2B4O7 aqueous solution (P / B=1:2) with a metal ion concentration of 5wt%.

[0094] Example 4

[0095] The present example provides an active carbon for vehicles, and a preparation method of the active carbon for vehicles is different from that of Example 1 only in that:

[0096] In the present example, the alkali metal composite salt is modified to a NaCl, NaH2PO4 and Na2B4O7 aqueous solution (Cl / (P+B)=1:10) with a metal ion concentration of 5wt%.

[0097] Example 5

[0098] The present example provides a vehicle activated carbon, the preparation method of which comprises the following steps:

[0099] The anthracite is crushed to a particle size of 2 μm, 1000 g of the crushed product is mixed with 300 g of coal tar, 4 g of KCl and 11 g of K3PO4 aqueous solution 1200 g (Cl / P = 1:3), and then extruded and granulated after kneading for 25 minutes, and dried to obtain a shaped body;

[0100] The shaped body is first pre-oxidized in air at 220°C for 5 hours, then carbonized at 500°C for 6 hours, and finally activated in water vapor at 900°C for 5 hours under a mass-based flow rate of 0.1 L / h.kg, to obtain a precursor;

[0101] The precursor is continuously pickled with 3% hydrochloric acid at 80°C for 30 minutes, and then repeatedly washed with deionized water at 100°C for 1 hour until the pH value of the washing liquid approaches 7, and dried at 200°C to obtain the vehicle activated carbon with a water content of <5%.

[0102] Example 6

[0103] The present example provides a vehicle activated carbon, the preparation method of which comprises the following steps:

[0104] The coconut shell char is crushed to a particle size of 100 μm, 1000 g of the crushed product is mixed with 250 g of medium temperature pitch, 60 g of castor oil, 27 g of KCl and 76 g of K2B4O7 (Cl / B = 1:8), and then 1200 g of water is added, and then extruded and granulated after kneading for 25 minutes, and dried to obtain a shaped body;

[0105] The shaped body is first pre-oxidized in air at 300°C for 4 hours, then carbonized at 600°C for 6 hours, and finally activated in a mixed gas of carbon dioxide at 100 L / h.kg mass-based flow rate and water vapor at 0.05 L / h.kg mass-based flow rate at 950°C for 4 hours, to obtain a precursor;

[0106] The precursor is intermittently pickled with 3% hydrochloric acid at 80°C for 60 minutes (each pickling for 20 minutes, repeated pickling for 3 times), and then repeatedly washed with deionized water at 100°C for 1 hour until the pH value of the washing liquid approaches 7, and dried at 200°C to obtain the vehicle activated carbon with a water content of <5%.

[0107] Comparative Example 1

[0108] The present comparative example provides a vehicle activated carbon, which is only different from Example 1 in that:

[0109] The present comparative example omits the step of mixing the alkali metal composite salt.

[0110] Comparative Example 2

[0111] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0112] This comparative example modifies the alkali metal complex salt to a NaCl aqueous solution having a metal ion concentration of 5 wt%.

[0113] Comparative Example 3

[0114] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0115] This comparative example modifies the alkali metal complex salt to a NaH2PO4 aqueous solution having a metal ion concentration of 5 wt%.

[0116] Comparative Example 4

[0117] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0118] This comparative example modifies the alkali metal complex salt to a Na2B4O7 aqueous solution having a metal ion concentration of 5 wt%.

[0119] Comparative Example 5

[0120] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0121] This comparative example modifies the alkali metal complex salt to a Na3PO4 and H3PO4 aqueous solution (Na / P mass ratio = 1.3:1) having a metal ion concentration of 5 wt%.

[0122] Comparative Example 6

[0123] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0124] This comparative example modifies the alkali metal complex salt to a Na2B4O7 and H3BO3 aqueous solution (Na / B mass ratio 1.2:1) having a metal ion concentration of 5 wt%.

[0125] Comparative Example 7

[0126] This comparative example provides an activated carbon for vehicle use, which differs from Example 1 only in that:

[0127] This comparative example modifies the alkali metal complex salt to a NaCl and H3BO3 aqueous solution (Na / B mass ratio 1.2:1) having a metal ion concentration of 5 wt%.

[0128] Comparative Example 8

[0129] The comparative example provides a vehicle active carbon, which is only different from example 1 in that:

[0130] The comparative example modifies the alkali metal complex salt to NH4Cl-AlCl3-ZnCl2 / NaH2PO4 (NH4Cl:AlCl3:ZnCl2:NaH2PO4 mass ratio of 3:3:3:5) with a metal ion concentration of 5wt%.

[0131] Performance detection:

[0132] The vehicle active carbon provided by the above examples and comparative examples is subjected to performance detection (specific surface area, pore volume, butane working capacity BWC, flushing rate and wear resistance), and the results are shown in Table 1.

[0133] Among them, the pores with a diameter <2nm are micropores, the pores with a diameter of 2-50nm are mesopores, and the pores with a diameter >50nm are macropores;

[0134] The specific surface area is calculated by obtaining the nitrogen adsorption isotherm at the boiling point temperature of liquid nitrogen, and then calculating the specific surface area by the BET method;

[0135] The pore volume is calculated by the cumulative pore volume in the density function theory;

[0136] 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;

[0137] The strength test method is obtained according to GBT 12496.6-1999 Test Method for Strength of Wood-based Activated Carbon.

[0138] Table 1

[0139]

[0140]

[0141] According to Table 1, the following points can be known:

[0142] (1) From the analysis of Examples 1-4 and Comparative Examples 2-4, it can be seen that the use of NaCl-NaH2PO4, NaCl-Na2B4O7, NaH2PO4-Na2B4O7, NaCl-NaH2PO4-Na2B4O7 complex salts in turn has a synergistic effect relative to the use of NaCl, NaH2PO4 and Na2B4O7 salts alone in turn in Comparative Examples 2-4. Not only is the reactivity increased, the specific surface area and pore volume are enlarged, but also the ability to form mesopores is strengthened, so that the mesopore rate of the sample is significantly increased, and the butane working capacity and the flushing rate are significantly improved;

[0143] (2) From the comprehensive analysis of Examples 5 and 6, it can be seen that when using Scheme B, the use of anthracite and carbonized material as raw materials, KCl-K3PO4 and KCl-K2B4O7 as complex salts, and the combination of coal tar and pitch as the binding system in combination with the pre-oxidation, carbonization and steam activation processes can all obtain activated carbon whose butane working capacity and strength both reach the standard of activated carbon for vehicle use;

[0144] (3) The preparation methods provided in Comparative Examples 1-4 are the same as those in Examples 1-3, and the only difference is the use of different chemical reagents: no chemical reagent is used in Comparative Example 1, and the sample is activated by pure CO2. After activation, the sample is mainly microporous, so the flushing rate is low and the butane working capacity is low; only NaCl is used in Comparative Example 2, and the specific surface area, total pore volume, micropore volume and mesopore volume of the product are comparable to those in Comparative Example 1, indicating that the use of NaCl alone has no catalytic function for CO2, and the sample after activation is also mainly microporous, so the butane working capacity is low; only NaH2PO4 is used in Comparative Example 3, and the specific surface area and total pore volume of the product are lower than those in Comparative Example 1, but the mesopore volume is higher, and the mesopore rate is the highest among Comparative Examples 1-4, indicating that NaH2PO4 has the strongest mesopore-forming ability, but the addition of NaH2PO4 affects the activity of CO2 activation. The butane working capacity of the product is low due to the low total pore volume; only Na2B4O7 is used in Comparative Example 4, and the specific surface area, total pore volume and mesopore volume of the product are all higher than those in Comparative Example 1, indicating that Na2B4O7 not only has a catalytic effect, but also has a mesopore-forming ability, but the mesopore-forming ability is lower than that of NaH2PO4; in addition, the butane working capacity is low due to the low mesopore rate of Na2B4O7.

[0145] (4) The preparation raw materials and preparation methods of Comparative Examples 5-7 are the same as those of Examples 1-4, except that the ratio of the alkali metal composite salt used in the Comparative Examples is different from that of Examples 1-4. Comparative Example 5 uses Na3PO4-H3PO4 system (Na / P mass ratio 1.3:1), Comparative Example 6 uses Na2B4O7 and H3BO3 (Na / B mass ratio 1.2:1), and Comparative Example 7 uses NaCl-H3BO3 (Na / B mass ratio 1.2:1). The results show that the specific surface area, total pore volume, micropore volume and mesopore volume of the product using the above-mentioned active agent are much lower than those of Example 1 using the same Na / P ratio (Cl / P molar ratio 1:1.3, converted into mass ratio Na / P 1.3:1) of the composite phosphorus salt system of NaCl-NaH2PO4 and Example 2 using the same Na / B ratio (Cl / B molar ratio 1:6.25, converted into mass ratio Na / B 1.2:1) of the composite boron salt system of NaCl-Na2B4O7. This shows that the combination of phosphoric acid, boronic acid / alkali metal phosphate, borate and chloride salt suitable for viscose fiber raw materials is not suitable for the high-carbon raw material of the present application, because there is no raw material cellulose hydrolysis and aromatization process, and the activation path and pore forming mechanism are different from those of the present application.

[0146] At the same time, the composite salt system NH4Cl-AlCl3-ZnCl2 / NaH2PO4 used in Comparative Example 8 is compared with the NaCl-NaH2PO4 provided in Example 1, and the results are the same as described above. In addition, the above-mentioned examples and comparative examples use the method of first crushing the activated product and then forming it with a binder, and as long as the amount of binder and water is controlled, the product has a strength that meets the standard (>85%).

[0147] The applicant states 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 of the present application, equivalent replacement of each raw material of the product of the present application and addition of auxiliary ingredients, selection of specific methods, etc. fall within the scope of protection and disclosure of the present application.

[0148] The applicant states that the detailed process flow of the present application is illustrated by the above examples, but the present application is not limited to the above detailed process flow, i.e. it does not mean that the present application must rely on the above detailed process flow to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application and addition of auxiliary ingredients, selection of specific methods, etc. fall within the scope of protection and disclosure of the present application.

Claims

1. An activated carbon for automotive use, characterized in that, The raw materials for preparing the automotive activated carbon include high-carbon substances and alkali metal composite salts; The carbon content of the high-carbon substance is ≥80%; The alkali metal complex salt includes a combination of alkali metal chloride salt and alkali metal boron salt, or a combination of alkali metal phosphate salt and alkali metal boron salt, or a combination of alkali metal chloride salt, alkali metal phosphate salt and alkali metal boron salt. The mass ratio of metal ions to high-carbon substances in the automotive activated carbon is (0.5~5):100; When the alkali metal complex salt is a mixture of alkali metal chloride salt and alkali metal boron salt, the molar ratio of chlorine to boron is 1:(4~28). When the alkali metal complex salt is a mixture of alkali metal phosphate salt and alkali metal boron salt, the molar ratio of phosphorus to boron is 1:(1~4); When the alkali metal complex salt is a mixture of alkali metal chloride salt, alkali metal phosphate salt and alkali metal boron salt, the molar ratio of chlorine to the sum of boron and phosphorus, Cl:(P+B), is 1:(5~35). The preparation method of the automotive activated carbon includes scheme A and / or scheme B; Scheme A includes: mixing activated carbon and alkali metal composite salt according to the formula, and then performing physical activation treatment, washing, drying, pulverizing and extrusion molding in sequence to obtain the automotive activated carbon; Scheme B includes: drying the matrix material and then pulverizing it; mixing it with alkali metal composite salt according to the formula and then extruding it; and then sequentially performing pre-oxidation, carbonization, physical activation treatment, cleaning and drying to obtain the automotive activated carbon.

2. The activated carbon for vehicles according to claim 1, characterized in that, The high-carbon material includes matrix materials or activated carbon.

3. The activated carbon for vehicles according to claim 2, characterized in that, The matrix material includes mineral raw materials and / or carbides.

4. The activated carbon for vehicles according to claim 3, characterized in that, The mineral raw materials include any one or a combination of at least two of bituminous coal, anthracite, petroleum coke, or bitumen.

5. The activated carbon for vehicles according to claim 1, characterized in that, The specific surface area of ​​the activated carbon is 20-1000 m². 2 / g.

6. The activated carbon for vehicles according to claim 1, characterized in that, The specific surface area of ​​the activated carbon is 600-1000 m². 2 / g.

7. The activated carbon for vehicles according to claim 1, characterized in that, The activated carbon has a particle size of 0.05-6.00 mm.

8. The activated carbon for vehicles according to claim 1, characterized in that, The activated carbon has a particle size of 1.00-3.00 mm.

9. A method for preparing automotive activated carbon as described in any one of claims 1-8, characterized in that, The preparation method includes scheme A and / or scheme B; Scheme A includes: mixing activated carbon and alkali metal composite salt according to the formula, and then performing physical activation treatment, washing, drying, pulverizing and extrusion molding in sequence to obtain the automotive activated carbon; Scheme B includes: drying the matrix material and then pulverizing it; mixing it with alkali metal composite salt according to the formula and then extruding it; and then sequentially performing pre-oxidation, carbonization, physical activation treatment, cleaning and drying to obtain the automotive activated carbon.

10. The method for preparing automotive activated carbon according to claim 9, characterized in that, The activation gases used in the physical activation process include carbon dioxide and / or water vapor.

11. The method for preparing automotive activated carbon according to claim 10, characterized in that, The mass-based flow rate of the carbon dioxide is 100~1500 L / h·kg.

12. The method for preparing automotive activated carbon according to claim 10, characterized in that, The mass basis flow rate of the water vapor is 0.05~1L / h·kg.

13. The method for preparing automotive activated carbon according to claim 10, characterized in that, The physical activation treatment takes 2.5 to 8 hours.

14. The method for preparing automotive activated carbon according to claim 10, characterized in that, The temperature for the physical activation treatment is 900~1100℃.

15. The method for preparing automotive activated carbon according to claim 9, characterized in that, The cleaning process includes sequential acid washing and water washing.

16. The method for preparing automotive activated carbon according to claim 15, characterized in that, The acid used in the pickling process includes hydrochloric acid.

17. The method for preparing automotive activated carbon according to claim 16, characterized in that, The concentration of the hydrochloric acid is 0.1~15wt%.

18. The method for preparing automotive activated carbon according to claim 15, characterized in that, The pickling time is 10 min to 24 h.

19. The method for preparing automotive activated carbon according to claim 15, characterized in that, The pickling temperature is 10~80℃.

20. The method for preparing automotive activated carbon according to claim 15, characterized in that, The washing time is 1 to 24 hours.

21. The method for preparing automotive activated carbon according to claim 15, characterized in that, The temperature of the water wash is 10~120℃.

22. The method for preparing automotive activated carbon according to claim 9, characterized in that, The drying temperature is 80~200℃.

23. The method for preparing automotive activated carbon according to claim 9, characterized in that, The average particle size of the matrix material after pulverization, as described in Scheme B, is 2~100μm.

24. The method for preparing automotive activated carbon according to claim 9, characterized in that, The pre-oxidation temperature described in Scheme B is 200~400℃.

25. The method for preparing automotive activated carbon according to claim 9, characterized in that, The pre-oxidation temperature described in Scheme B is 220~300℃.

26. The method for preparing automotive activated carbon according to claim 9, characterized in that, The pre-oxidation time described in Scheme B is 0.5~20h.

27. The method for preparing automotive activated carbon according to claim 9, characterized in that, The pre-oxidation time described in Scheme B is 1~8h.

28. The method for preparing automotive activated carbon according to claim 9, characterized in that, The carbonization temperature described in Scheme B is 300~900℃.

29. The method for preparing automotive activated carbon according to claim 9, characterized in that, The carbonization temperature described in Scheme B is 300~600℃.

30. The method for preparing automotive activated carbon according to claim 9, characterized in that, The carbonization time described in Scheme B is 0.5~20h.

31. The method for preparing automotive activated carbon according to claim 9, characterized in that, The carbonization time described in Scheme B is 1 to 10 hours.

32. The method for preparing automotive activated carbon according to claim 9, characterized in that, The extrusion molding process yields cylindrical granules with a diameter of 1.5~2.5 mm.

33. The method for preparing automotive activated carbon according to claim 9, characterized in that, The moisture content of the automotive activated carbon is <5%.

34. The method for preparing automotive activated carbon according to claim 9, characterized in that, The preparation method includes scheme A and / or scheme B; Scheme A includes: mixing activated carbon and alkali metal composite salt according to the formula, then performing physical activation treatment at 900~1100℃ for 2.5~8h using an activation gas, then acid washing with 0.1~15wt% hydrochloric acid at 10~80℃ for 10min~24h, followed by water washing at 10~120℃ for 1~24h, drying at 80~200℃, and then pulverizing and extruding to obtain the automotive activated carbon with a water content of <5%; Scheme B includes: drying the matrix material and then pulverizing it to an average particle size of 2-100 μm; mixing it with alkali metal composite salt according to the formula and then extruding it; then pre-oxidizing it at 200-400℃ for 0.5-20 h, carbonizing it at 300-900℃ for 0.5-20 h, then physically activating it with an activating gas at 900-1100℃ for 2.5-8 h, then acid washing it with 0.1-15wt% hydrochloric acid at 10-80℃ for 10 min-24 h, then washing it with water at 10-120℃ for 1-24 h, and finally drying it at 80-200℃ to obtain the automotive activated carbon with a water content of <5%.

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