CN107285309A - A kind of oily sludge and the biomass combined method for preparing multistage mesoporous activated carbon - Google Patents

Abstract

The invention discloses a method for compounding oily sludge and biomass to prepare multi-level porous activated carbon, which comprises the following steps: centrifuging the oily sludge to take the upper oil phase, mixing it with biomass particles, putting it into a tube furnace, Under the protection of the atmosphere, the temperature was raised to 350-450°C at 2-5°C/min and kept for 90-120min, cooled to room temperature to complete the carbonization process; then the solid and KOH were evenly mixed, and the temperature was raised to 800-850°C under the protection of an inert atmosphere and kept for 60 minutes. ‑90min, natural cooling to complete the activation process; the resulting solids were washed, dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of more than 1800m ² /g and an average pore diameter of about 3nm. The invention uses biomass and oily sludge with high viscosity and complex components as raw materials, and has the advantages of wide source of raw materials, low cost, simple equipment, no pollution, and the by-products in the preparation process can be recycled.

Description

A method for compounding oily sludge and biomass to prepare hierarchical porous activated carbon

technical field

The invention relates to the technical field of oily sludge toxic and harmful solid waste in the petrochemical industry and the resource utilization of biomass waste in the agricultural production process, in particular to a method for preparing multi-level porous activated carbon by compounding oily sludge and biomass.

Background technique

Oily sludge is a kind of viscous solid waste with highly emulsified water, oil and slag produced in the process of crude oil exploration, mining, transportation, storage, tank cleaning and refining. The composition of oily sludge is complex, containing a large amount of crude oil, asphaltene, wax, moisture, solid particles and various chemicals. It is difficult to degrade, toxic, harmful, etc. It is not easy to handle and pollutes the environment. It belongs to the category of hazardous waste in the national hazardous waste list. HW08. Generally, oily sludge contains 30-50% water, 10-12% solid particles and 30-50% oil, and the oil phase is composed of saturated hydrocarbons, aromatic hydrocarbons, colloids and asphaltenes. The presence of colloids and asphaltene promotes the stability of the emulsion in oily sludge, which greatly increases the difficulty of oily sludge treatment. At present, the incineration method is one of the harmless treatment methods for oily sludge, but there are problems of high cost and easy to produce secondary pollution. The resource treatment methods mainly include: mechanical separation, chemical extraction and thermal conversion methods, but due to the high viscosity and high toxicity of oily sludge, there are also shortcomings such as unsatisfactory results and complicated operations.

As a kind of agricultural waste, biomass has the advantages of wide sources, high output, low price, and short growth cycle. Compared with raw coal, biomass has no cohesiveness and does not need special treatment such as breaking sticks. As a large agricultural country, our country produces a huge amount of biomass such as straw, rice husk, and corn cob every year. Traditional biomass disposal methods, such as incineration, are prone to waste of resources and environmental pollution. At present, the resource utilization method of biomass is mainly thermal conversion method, but there are also problems such as low product quality and complicated equipment.

Activated carbon is a material with a high specific surface area and a porous structure on the surface. Due to its unique adsorption surface structure characteristics and surface chemical properties, activated carbon has strong adsorption performance and catalytic performance. The raw materials for the preparation of activated carbon are sufficient and safe, acid and alkali resistance, heat resistance, insoluble in water and organic solvents, and easy to regenerate , is an environmentally friendly adsorbent. At present, activated carbon has been widely used in chemical industry, environmental protection, food processing, metallurgy, drug refining, military chemical protection and other fields. Ordinary activated carbon materials are amorphous carbon obtained by processing raw materials such as coal, coconut shells, fruit shells, and wood chips. The specific surface area is usually less than 1100m ² /g and mostly mesoporous. The activated carbon used for special purposes is made of expensive asphaltene and high molecular polymer materials, with a specific surface area greater than 2000m ² /g. Hierarchical activated carbon refers to a large number of mesopores and micropores distributed in activated carbon at the same time, which has a high adsorption capacity for gas molecules and ions and organic pollutants in the liquid phase.

The preparation technology of multi-level porous activated carbon from oily sludge and biomass mixture belongs to the field of resource utilization of hazardous solid waste. The present invention takes the oily sludge produced in the process of crude oil production and processing and the biomass mixture produced in agricultural production as objects, and according to the principle of "harmless, reduced, resourceful", aims at oily sludge itself which is difficult to handle, Due to the characteristics of high asphaltene content and large biomass output, the technology of preparing hierarchical porous activated carbon from oily sludge and biomass mixture is studied. It provides new ideas and new methods for resource utilization and industrial production of oily sludge and biomass, and has important practical significance.

Chinese patent CN201611234477.1 discloses a preparation method of biomass-residue co-coking activated carbon. Under the protection of inert gas, biomass and residue are subjected to co-coking reaction to obtain co-coking; treatment and ash removal pretreatment to obtain pretreated co-coking; under the protection of inert gas, roast the pre-treated co-coking to obtain bio-based carbon materials; Activated carbon with high specific surface area and high pore volume.

Contents of the invention

The purpose of the present invention is a method for compounding oily sludge and biomass to prepare hierarchical porous activated carbon, and provides a new idea for resource utilization of oily sludge and biomass waste. The invention has the advantages of low cost, easy operation, no pollution, simple equipment and low investment, and by-products in the preparation process can be recycled and reused, and various components of oil sludge and biomass can be fully recycled and utilized.

In order to achieve the above object, the technical scheme adopted in the present invention comprises:

A method for preparing hierarchically porous activated carbon by compounding oily sludge and biomass, the specific surface area of the activated carbon is above 1800m ² /g, the pore size distribution is mainly between 0.5-4nm, the average pore size is about 3nm, and the pore volume is greater than 1.5 cm ³ /g; including the following steps:

Step (1), after centrifuging the oily sludge, removing the moisture in the middle layer and the solid slag in the bottom layer to obtain an oil phase product in the upper layer;

Step (2), crushing and grinding the biomass to obtain biomass particles;

Step (3), after uniformly mixing the oil phase product obtained in step (1) and the biomass particles obtained in step (2) at a mass ratio of 1: (0.2-1), put them into a corundum crucible, and under the protection of an inert atmosphere Raise the temperature at 2-5°C/min to 350-450°C and keep it warm for 90-120min, cool down to room temperature naturally to obtain blocky solids, and grind them into granules;

Step (4), uniformly mix the solid particles obtained in step (3) with KOH powder and put them into a corundum crucible, raise the temperature to 800-850°C under the protection of an inert atmosphere, keep it warm for 60-90min, cool naturally to room temperature, take it out and use Rinse with deionized water until the filtrate is neutral, dry and grind to obtain the hierarchically porous activated carbon.

The oily sludge is a black emulsion with high viscosity and complex components produced during crude oil production and processing.

The biomass is solid waste such as straw, rice husk, etc. produced in the agricultural production process.

The centrifugation parameters described in step (1) are: 3000-4000rpm, centrifugation for 10-20min, and the process temperature is 15-20°C.

The biomass particles described in step (2) are about 60-80 mesh.

The grinding particle size described in step (3) is 1.5-2mm

The mixing mass ratio of solid particles and KOH powder in step (4) is 1:(3-5).

The method for preparing hierarchically porous activated carbon by compounding oily sludge and biomass of the present invention has the following advantages:

1. The preparation process is simple: through a series of methods such as oily sludge centrifugation, biomass crushing, raw material mixing, carbonization, activation, washing, drying, grinding, etc., the oily sludge and biomass are treated to prepare hierarchical porous activated carbon. The preparation process is simple, the device is easy to obtain, the operation steps are few, and the feasibility is high;

2. Raw materials and additives are easy to obtain: the oily sludge required for preparation is hazardous solid waste generated during crude oil production and processing; the biomass required for preparation is solid waste generated during agricultural production, and the output is large; the preparation process The required additives are readily available;

3. Full utilization of raw materials: The oil product produced during the carbonization process of oily sludge and biomass mixture has low viscosity and small molecular weight, and can be recycled as high-quality oil product after treatment.

4. The prepared hierarchical porous activated carbon is of high quality: the specific surface area is not less than 1800m ² /g, the pore size distribution is mainly between 0.5-4nm, the average pore size is about 3nm, and the pore volume is greater than 1.5cm ³ /g.

Description of drawings

Fig. 1 is a flow chart of the method for preparing hierarchically porous activated carbon by compounding oily sludge and biomass in the present invention.

Figure 2 is a scanning electron micrograph of the activated carbon obtained in Example 1 of the present invention.

Fig. 3 is a nitrogen adsorption-desorption isotherm diagram of the activated carbon obtained in Example 1 of the present invention.

Fig. 4 is the pore size distribution diagram of the activated carbon obtained in Example 1 of the present invention.

detailed description

Hereinafter, the present invention will be further illustrated by examples, but not limited to any one of the following examples. Fig. 1 is a flow chart of the method for preparing hierarchically porous activated carbon by compounding oily sludge and biomass in the present invention.

Example 1

Oily sludge with a mass content of asphaltene of 6% was used as a raw material, and after centrifugation at 20° C. at 3000 rpm for 10 min, the solid particles and moisture at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.25. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere, the heating condition was 4°C/min, the temperature was raised to 400°C and kept for 120 minutes, and the solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:4, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, nitrogen is used as a protective atmosphere and heated The temperature is 800°C, and after 60 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product was washed with deionized water until the filtrate was neutral, then dried and ground to obtain the hierarchically porous activated carbon. The activated carbon scanning electron microscope is shown in FIG. 2 . The specific surface area of the prepared activated carbon is 1849m ² /g, and the pore volume is 1.58cm ³ /g. As can be seen in Figure 3, the adsorption capacity of the prepared activated carbon increases significantly when the relative pressure is lower than 0.1 and between 0.1 and 0.9, indicating that Both micropores and mesopores exist in activated carbon. As shown in Figure 4, the pore size distribution of activated carbon is between 0.8-4.1nm, the average pore size is 2.81nm, and the adsorption capacity of methylene blue in water is 931mg/g.

Example 2

Oily sludge with an asphaltene mass content of 11% was used as a raw material, and after centrifugation at 3500 rpm for 10 min at 20°C, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.25. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere. The heating condition was 4°C/min. After the temperature was raised to 400°C, it was kept for 120 minutes, and a solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:4, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, use nitrogen as a protective atmosphere and heat The temperature is 800°C, and after 60 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 2142m ² /g, a pore volume of 1.85cm ³ /g, an average pore diameter of 3.04nm, and an adsorption capacity of methylene blue in water of 1038mg/g.

Example 3

Oily sludge with an asphaltene mass content of 11% was used as a raw material, and after centrifugation at 20°C at 4000 rpm for 15 minutes, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:1. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere. The heating condition was 4°C/min. After the temperature was raised to 400°C, it was kept for 120 minutes, and a solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:4, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, use nitrogen as a protective atmosphere and heat The temperature is 800°C, and after 60 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 1976m ² /g, a pore volume of 1.68cm ³ /g, an average pore diameter of 2.74nm, and an adsorption capacity of methylene blue in water of 891mg/g.

Example 4

Oily sludge with an asphaltene mass content of 11% was used as a raw material, and after centrifugation at 20°C at 3000 rpm for 15 minutes, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.3. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere. The heating condition was 4°C/min. After the temperature was raised to 400°C, it was kept for 120 minutes, and a solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:4, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, use nitrogen as a protective atmosphere and heat The temperature is 800°C, and after 60 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 2254m ² /g, a pore volume of 1.87cm ³ /g, an average pore diameter of 3.12nm, and an adsorption capacity of methylene blue in water of 1044mg/g.

Example 5

Oily sludge with a mass content of asphaltene of 6% was used as a raw material, and after centrifugation at 15°C at 4000rpm for 20min, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.2. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere. The heating condition was 4°C/min. After the temperature was raised to 400°C, it was kept for 120 minutes, and a solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:4, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, use nitrogen as a protective atmosphere and heat The temperature is 800°C, and after 60 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 1985m ² /g, a pore volume of 1.61cm ³ /g, an average pore diameter of 2.95nm, and an adsorption capacity of methylene blue in water of 895mg/g.

Example 6

Oily sludge with a mass content of asphaltene of 6% was used as a raw material, and after centrifugation at 20°C at 4000rpm for 10min, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.2. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere, the heating condition was 2°C/min, the temperature was raised to 350°C and kept for 120 minutes, and the solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:3, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, nitrogen is used as a protective atmosphere and heated The temperature is 850°C, and after 90 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 1885m ² /g, a pore volume of 1.78cm ³ /g, an average pore diameter of 2.90nm, and an adsorption capacity of methylene blue in water of 845mg/g.

Example 7

Oily sludge with an asphaltene content of 11% was used as a raw material, and after centrifugation at 17°C at 4000rpm for 10min, the solid particles and water at the bottom were removed, and the upper oil phase was taken. Rice husks are used as biomass raw materials, and rice husk particles of 60-80 meshes are obtained after crushing and grinding. Mix the upper oil phase and rice husk particles evenly at a mass ratio of 1:0.5. The mixture was put into a corundum crucible and heated and carbonized in a tube furnace with nitrogen as an atmosphere. The heating condition was 5°C/min. After the temperature was raised to 450°C, it was kept for 90 minutes, and a solid product was obtained after natural cooling to room temperature. Grind the solid product to a solid particle of about 2mm, and mix it with KOH powder at a mass ratio of 1:5, put it into a corundum crucible, and place it in a tube furnace for heating and activation. During the activation process, nitrogen is used as a protective atmosphere and heated The temperature is 820°C, after 70 minutes of heat preservation, it is naturally cooled to room temperature. The obtained product is washed with deionized water until the filtrate is neutral, then dried and ground to obtain the hierarchically porous activated carbon. The prepared activated carbon has a specific surface area of 2112m ² /g, a pore volume of 1.83cm ³ /g, an average pore diameter of 3.08nm, and an adsorption capacity of methylene blue in water of 1103mg/g.

Claims (8)

1. a kind of oily sludge exists with the biomass combined method for preparing multistage mesoporous activated carbon, the specific surface area of the activated carbon 1800m²/ more than g, pore-size distribution is mainly between 0.5-4nm, and average pore size is more than 1.5cm in 3nm or so, pore volume³/g；Its It is characterised by that this method comprises the following steps：

Step (1), oily sludge is centrifuged after, remove middle level moisture and bottom solid slag, obtain upper oil phase production Thing；

Step (2), by biomass crushing grinding, obtain biological particles；

Step (3), by obtained by the oil-phase product obtained by step (1) and step (2) biological particles uniformly mixing after, be put into just In beautiful crucible, it is warming up to 350-450 DEG C with 2-5 DEG C/min under inert atmosphere protection and is incubated 90-120min, naturally cool to Blocks of solid is obtained after room temperature, particle is ground to form；

Step (4), step (3) obtained to be put into corundum crucible after solid particle is uniformly mixed with KOH powder, in inert atmosphere 800-850 DEG C is warming up under protection, 60-90min is incubated, room temperature is naturally cooled to, with deionized water rinsing to filtrate after taking-up In neutrality, drying and grinding obtains the multistage mesoporous activated carbon.

2. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature It is a kind of high viscosity, the black milk of complicated component produced in crude oil production process to be described oily sludge.

3. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature The solid waste for being described biomass to produce in agricultural production process.

4. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature It is that the parameter of noncentricity described in step (1) is：3000-4000rpm, centrifuges 10-20min, and process temperature is 15-20 DEG C.

5. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature It is 60-80 mesh or so to be the biological particles described in step (2).

6. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature It is 1.5-2m to be the abrasive grains size described in step (3).

7. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature The mass ratio for being the biological particles obtained by the oil-phase product and step (2) obtained by step (3) step (1) is 1：(0.2-1).

8. a kind of oily sludge as claimed in claim 1 and the biomass combined method for preparing multistage mesoporous activated carbon, its feature The mixing quality ratio for being step (4) solid particle and KOH powder is 1：(3-5).