CN101580729B - Method for preparing mesophase asphalt by coal liquefaction residue - Google Patents

Abstract

The invention relates to a method for preparing mesophase asphalt by coal liquefaction residue. In the method, the coal liquefaction residue is ground, screened and dried, and is extracted at certain temperature for certain time by using organic solvent as extracting solvent; the extracted mixed liquor is filtered, purified and evaporated; the extracting solvent in the extract liquor is evaporatedto obtain refined coal liquefaction oil asphalt, thus obtaining the mesophase asphalt by charring for 4-10 hours in a high-pressure autoclave under the conditions of 410-460 DEG C, 3-4MPa of constant pressure and stirring. The method has simple process and convenient and safe operation, the mesophase asphalt with high quality is prepared and can be used as raw materials of high power and ultra hi gh power graphite electrode, carbon fiber and the like.

Description

The method for preparing mesophase pitch with coal liquefaction residue

Technical field

The present invention relates to coal deep processing field, particularly relate to simple, easy to operate, the high-quality method for preparing mesophase pitch with coal liquefaction residue of technological process.

Background technology

Along with economy improves constantly to high speed sane development and living standards of the people, China has particularly got into rapid growth period to the demand of oil to demands for energy.China's primary energy source characteristics of resources is " many coals, few oil, a scarce Sweet natural gas ".Oil and gas import big country is changed into from oil exportiog countries in China.A large amount of imported crude oils; Not only increased degree of dependence to foreign resources; And the fluctuation of international petroleum market and change the safety of Economic development and the power supply directly influence China, and along with the increase of global oil extraction and the minimizing of reserves, the breach of oil supply is increasing; Therefore make full use of the abundant in coal resource; Developing coal system oil tech energetically is the risk that diversification reduces oil supply, realizes an important approach of the energy, economy, harmonious development, and coal system oil tech will be the strategic emphasis of China's energy construction in this century.

In the DCL/Direct coal liquefaction production process; No matter use which kind of direct coal liquefaction technology; No matter adopt which kind of solid-liquid separating method (underpressure distillation, SX and filtration), the inorganic mineral carried secretly in a certain amount of unreacted coal, the coal is always arranged and add the solid materials such as catalyzer of coal slurry and the intermediate product of some gelatin liquefactions is discharged liquefying plant together.Surplus materials after the parting liquid carburetion is called liquefied residue, and it is a kind of high-carbon, high ash and doctor positive material, and output generally reaches about 30% of feed coal.So still be that environmental angle is considered no matter, all be the important component part of coal liquefaction craft exploitation to the utilization research of residue from economy.

Now to the utilization of coal liquefaction residue mainly burning, coking system oil, gasification hydrogen-producing etc. traditional aspect.The ratio of carbon-hydrogen of liquefied residue is higher, and directly being used for burning not only influences the economy of gelatin liquefaction and be that sulphur content is very high in the resulting residue of liquefaction process of catalyzer with the sulphur iron-based, and directly going burns runs counter to the original intention of liquefaction process as clean coal technology.Asphaltene in the liquefied residue is converted into BO and retortable oil is the yield that coking system oil has increased the liquid oil of coal liquefaction craft; But liquefied residue can not obtain utilizing fully, need further seek coking primary product---the utilization of semicoke or coke.The tradition utilization of liquefied residue all can not obtain best target product.The massfraction of carbon is higher in the coal liquefaction residue, and the asphaltene of different sources is in composition, structure and different in nature, but the asphaltene molecule has the aromaticity height, and therefore polymerization or crosslinked characteristics are suitable as the raw material for preparing carbon material easily.Chinese patent ZL 200510047800.X discloses with the coal liquefied residue and has prepared carbon nano-material for the raw material plasma body.Chinese patent ZL 200610012547.9 discloses coal liquefaction residue as road asphalt modifier.The unique property of coal liquefaction residue more and more comes into one's own.

Carbon product is divided into two kinds in oil system and coal measures.Current international petroleum market is turbulent; And the energy characteristics of China's " rich coal oil starvation "; Make people feel that oil is the instability of raw material supply, the oil and gas price is rising violently always, will restructure the use of energy; Cause that countries in the world pay close attention to, so special concern coal measures carbon material goods more and more.The ratio of carbon-hydrogen of coal liquefaction residue is high, and aromaticity content is high, and utility value is high, can satisfy the requirement of extraordinary carbonaceous product through deep processing.The precursor of for example producing carbon material is a mesophase pitch; Then mesophase pitch is used to prepare superpower and ultra-high power graphite electrode, needle coke and asphalt carbon fiber, the ingredient requirement ash content that forms mesophase pitch is low, heteroatoms is few, structure is formed homogeneous and aromaticity content is high and be rich in a certain amount of alkyl short chain.Usually used coal-tar pitch and petroleum pitch can not satisfy above-mentioned condition fully, generally carries out raw materials pretreatment.Chinese patent ZL 87103787 has adopted the modulation of hydrogenation means to obtain mesophase pitch.DCL/Direct coal liquefaction is under HTHP, makes protium get into the molecular structure of coal and verivate thereof by means of hydrogen supply dissolvent and catalyzer, thereby coal is converted into liquid fuel or industrial chemicals.Be that coal liquefaction residue is that coal is through the solid product after the hydrogenation system oil; It not only comprises the condensation aromatic structure unit and the saturated hydrogenated aromatic structure of partial hydrogenation of 1～6 ring; And containing the normal paraffin that a series of carbon numbers do not wait, these normal paraffins exist with the side chain form of aromatic structure unit bonding.Coal liquefaction residue through after the solvent treatment is that liquefied coal coil bituminous ash content and heteroatoms etc. are removed basically, is suitable as the raw material of mesophase pitch.

Summary of the invention

The objective of the invention is present situation and deficiency to present coal liquefaction residue utilization; For abundant rational and effective is utilized coal liquefaction residue; The technology of exploitation high added value carbon material when improving coal utilization efficient; Be engaged in the development research and the production practice of gelatin liquefaction for many years through the contriver, exploitation provides a kind of solvent to recycle, and whole process of preparation need not a kind of method for preparing mesophase pitch with coal liquefaction residue of any catalyzer.

Provided by the inventionly prepare the method for mesophase pitch, it is characterized in that may further comprise the steps with coal liquefaction residue:

1. coal liquefaction residual powder preparation

Coal liquefaction residue is pulverized, and sieved, filter out the coal liquefaction residual powder of particle diameter below 3mm, with the coal liquefaction residual powder oven dry, make its moisture mass content≤3% then;

2. extraction

Step coal liquefaction residual powder 1. added in the stirring tank with extraction solvent extract; Wherein the mass ratio of coal liquefaction residual powder and extraction solvent is 1: 3 to 1: 10; Be preferably 1: 4 to 1: 8; Heat to 20 ℃～120 ℃ then, stirred 10 minutes～60 minutes, get the mixture of extraction liquid and residue powder;

Said extraction solvent is N; N-N,N-DIMETHYLACETAMIDE, furfural, N, one or more in dinethylformamide, THF, N-N-methyl-2-2-pyrrolidone N-, dithiocarbonic anhydride, quinoline or the pyridine, being mixed use can be in any ratio; Be preferably DMAC N,N or furfural;

3. filter

Adopt vacuum filtration to step 2. the mixture of coal liquefaction residual powder and solvent carry out suction filtration and get extraction liquid, wherein vacuum tightness is less than normal atmosphere;

4. evaporation

Step extraction liquid is 3. sent into the evaporation that heats up in the evaporating kettle; Be preferably than evaporating under the high 10-15 of the solvent for use boiling point ℃ temperature; Extraction solvent in the extraction liquid is evaporated; Make refining liquefied coal coil pitch, and the extraction solvent steam that is evaporated forms the extraction solvent repeated use after the condensing surface cooling;

5. the preparation of mesophase pitch

With step 4. liquefied coal coil pitch insert in the autoclave, nitrogen purging use in sealing back, is warming up to 410～460 ℃ with 2～3 ℃ of/minute intensification speed then, under agitation, constant voltage 3-4MPa is preferably 3.5MPa, charing 4～10 hours must mesophase pitch.

The method characteristics that prepare mesophase pitch with coal liquefaction residue provided by the invention are directly coal liquefaction residue to be extracted under solvent, and whole technological process is simple, and is easy and safe to operate.Coal liquefaction residue after SX has higher C/H atomic ratio; The characteristics of low ash content, low-sulfur, low quinoline insolubles QI and higher aromaticity content; For example be N; Solvend ash content behind the N-N,N-DIMETHYLACETAMIDE extraction coal liquefaction residue is 0.3%, and quinoline insolubles is 4.94%, the aromatic carbon rate is 76.50%.Prepared mesophase pitch softening temperature is lower than 330 ℃; Quinoline insolubles≤15%; The C/H atomic ratio is high, intermediate phase content>=90% that polarizing microscope records, and having wide area streamlined structure and fine fiber structure and global tissue structurally ordered is a kind of presoma of novel carbon material.Mesophase pitch is the high-quality presoma of preparation high added value raw material of wood-charcoal material; Like high-strength asphalt based carbon fiber, activated carbon with high specific surface area, charcoal electrical condenser, ultra-high power graphite electrode material, high temperature nuclear graphite; High heat conduction raw material of wood-charcoal material, fluorine raw material of wood-charcoal material etc., these senior raw material of wood-charcoal material have related to various fields such as national defense industry, aerospace, hard-core technology, daily life and have brought into play enormous function.This preparation mesophase pitch can be used as the raw material of superpower and ultra-high power graphite electrode and preparation thomel.Starting coal liquefaction residue is utilized in the carbon material aspect is liquefied coal coil bitumen production mesophase pitch; Not only make residue become high-end high value added product utilization by the low side utilization; And enlarge the scope of present gelatin liquefaction; Coal utilizaton rate and added value are improved greatly, thereby improve Coal Economy property.

Embodiment

Further specify the present invention with the following example, but protection scope of the present invention is not limited to the following example.

Embodiment 1, the 1000kg coal liquefaction residue pulverized, and sieved and filter out the coal liquefaction residual powder of particle diameter below 3mm, with the coal liquefaction residual powder oven dry, makes its moisture mass content≤3% then.

Then with the coal liquefaction residual powder 10kg and the extraction solvent N of drying; N-N,N-DIMETHYLACETAMIDE 40kg adds in the stirring tank together; Heat to 120 ℃ then; Stirred 60 fens mixture, utilize vacuum filtration that the mixture of coal liquefaction residue and solvent is carried out suction filtration and get extraction liquid, through detect solvend percentage extraction 50.12% (daf).

Extraction liquid is sent into the evaporation that heats up in the evaporating kettle, with the evaporation of the extraction solvent in the extraction liquid, produces refining liquefied coal coil pitch.The extraction solvent steam that is evaporated forms extraction solvent again and reuses after the condensing surface cooling.

Liquefied coal coil pitch is inserted in the autoclave, and nitrogen purging is used in the sealing back, and the temperature rise rate with 2～3 ℃/min is warming up to 440～460 ℃ then, and under agitation, mesophase pitch is produced in constant voltage 3.5MPa charing 8～10 hours.

Embodiment 2

Present embodiment preparation technology is same as embodiment 1, is not both in temperature to stir 10 fens down for 120 ℃, behind vacuum filtration, reclaims solvent and obtains liquefied coal coil pitch.Obtaining the solvend percentage extraction through detection is 59.30% (daf).

Embodiment 3

Present embodiment preparation technology is same as embodiment 1, is not both the 30kg furfural and replaces.Stirred 60 fens down for 20 ℃ in temperature, behind vacuum filtration, reclaim solvent and obtain liquefied coal coil pitch.Obtaining the solvend percentage extraction through detection is 46.12% (daf).

Embodiment 4

Present embodiment preparation technology is same as embodiment 1; Be not both liquefied coal coil pitch is inserted in the autoclave, nitrogen purging is used in the sealing back, is 2～3 ℃/minute to 440 ℃ with temperature rise rate then; Under stirring state, constant voltage 3.5MPa charing can be produced the streamlined mesophase pitch of wide area in 4 hours.

Embodiment 5

Present embodiment preparation technology is same as embodiment 1, and not being both extraction solvent is N, each 20kg of dinethylformamide and THF; Liquefied coal coil pitch is inserted in the autoclave; Nitrogen purging is used in sealing back, is warming up to 420 ℃ with 2～3 ℃/minute temperature rise rate then, under stirring state; Constant voltage 3.5MPa charing 8 hours can be produced the streamlined mesophase pitch of wide area.

Claims (2)

1. one kind prepares the method for mesophase pitch with coal liquefaction residue, it is characterized in that may further comprise the steps:

1. coal liquefaction residual powder preparation

Coal liquefaction residue is pulverized and sieved, filter out the coal liquefaction residual powder of particle diameter below 3mm, with the coal liquefaction residual powder oven dry, make its moisture mass content≤3% then;

2. extraction

With step 1. coal liquefaction residual powder add in the stirring tank with extraction solvent; Wherein the mass ratio of coal liquefaction residual powder and extraction solvent is 1: 3～1: 10, heats to 20 ℃～120 ℃ then, stirs 10～60 fens; Get mixture; Said extraction solvent is DMAC N,N, furfural, N, one or more in dinethylformamide, THF, N-N-methyl-2-2-pyrrolidone N-, dithiocarbonic anhydride, quinoline, the pyridine;

3. filter

With vacuum filtration to step 2. the mixture of coal liquefaction residual powder and extraction solvent carry out suction filtration, extraction liquid;

4. evaporation

With step 3. extraction liquid send into the evaporation that heats up in the evaporating kettle, the extraction solvent in extraction liquid evaporation is reclaimed, make refining liquefied coal coil pitch;

5. mesophase pitch preparation

With step 4. liquefied coal coil pitch insert in the autoclave, nitrogen purging use in sealing back, is warming up to 410～460 ℃ with 2～3 ℃/minute temperature rise rate then, under stirring state, constant voltage 3-4MPa, charing 4～10 hours must mesophase pitch.

According to claim 1 prepare the method for mesophase pitch with coal liquefaction residue, it is characterized in that said extraction solvent is DMAC N,N, furfural, the mass ratio of coal liquefaction residual powder and extraction solvent is 1:4～1:8; The 5. middle constant voltage of said step is 3.5MPa.