A method for determining biomass tar components

Abstract

The present invention discloses a method for determining biomass tar components, including: distilling biomass tar to obtain tar fractions and asphaltene; passing the tar fractions through a chromatography column to obtain aliphatic components, aromatic components, ester components and polar components respectively; determining the composition and content of aliphatic components, aromatic components, ester components and polar components by GC-MS method; in the case of the relative content of each component determined by GC-MS method, the final weight loss rate determined by a thermogravimetric analyzer is multiplied by the relative content value of each component determined by a gas chromatography-mass spectrometer to obtain the accurate content of each component in the tar. The present invention overcomes the problems existing in the existing biomass tar component analysis technology and the defects existing in the determination of tar composition by a single technology, and provides a method for efficiently and accurately analyzing biomass tar components and their contents by combining multiple technologies.

Description

Technical Field

[0001] The invention belongs to the field of biomass tar separation and detection, and specifically relates to a method for determining biomass tar components. Background Art

[0002] Biomass resources come from a wide range of sources, including agricultural waste, wood and forest waste, urban organic waste, algae biomass, and energy crops. Biomass can be converted into energy through thermochemical, biological, and physical processes. Thermochemical conversion includes different processes such as combustion, gasification, and pyrolysis. Among them, gasification technology is gaining more and more attention as a way to produce biomass energy, but the gas produced by this process usually contains unacceptable biomass tar. Tar will condense or aggregate into more complex structures on the export pipeline, heat exchanger, or particulate filter, resulting in a decrease in overall efficiency and an increase in process costs.

[0003] Therefore, tar cracking or removal technology is one of the most important technologies for implementing gasification technology, and understanding the tar composition and content is a prerequisite for selecting a suitable tar removal method and analyzing the tar cracking mechanism.

[0004] However, the composition of biomass tar is very complex. Currently, there are hundreds of identifiable components, and their composition and properties are different. In addition, a large proportion of substances cannot be detected.

[0005] Therefore, how to accurately quantitatively analyze and identify the compounds in biomass tar is a difficult problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for determining biomass tar components.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for determining biomass tar components, comprising:

[0010] The biomass tar is distilled to obtain a tar fraction and asphaltene;

[0011] The tar fraction is passed through a chromatography column to obtain aliphatic components, aromatic components, ester components and polar components respectively;

[0012] The composition and content of aliphatic components, aromatic components, ester components and polar components were determined by GC-MS; the functional groups in asphaltene were determined by Fourier transform infrared spectrometer.

[0013] As a preferred embodiment of the method for determining the components of biomass tar according to the present invention, the biomass tar is distilled, wherein the distillation boiling point is between 0 and 330°C.

[0014] As a preferred embodiment of the method for determining the components of biomass tar according to the present invention, the boiling point range is divided into 0-120°C, 120-170°C, 170-220°C, 220-270°C and 270-330°C by staged heating, wherein the fraction collected in the temperature section of 120-270°C is the tar fraction, and the fraction collected in the temperature section of 270-330°C is the asphaltene.

[0015] As a preferred embodiment of the method for determining biomass tar components of the present invention, the chromatography column comprises:

[0016] After activating the adsorbent, the chromatography column is loaded with a wet method;

[0017] The tar fraction is completely dissolved using an organic solvent to obtain a tar solution;

[0018] Pour the tar solution into the liquid storage ball of the chromatography column, select the appropriate eluent in the order of polarity from small to large to elute through the chromatography column, collect the eluate according to the group components, and analyze whether the elution is complete by combining the color developer and refractive index.

[0019] As a preferred embodiment of the method for determining biomass tar components of the present invention, the adsorbent is column chromatography silica gel and activated alumina, wherein:

[0020] The activation method of column chromatography silica gel includes extracting the silica gel with chloroform until it does not emit fluorescence, activating it in a forced air drying oven at 105-150° C. for 3-6 hours after the solvent evaporates, sealing it with a multi-layer sealing bag and placing it in a vacuum dryer for standby use;

[0021] The activation method of active alumina comprises the following steps: calcining the active alumina in a muffle furnace at 450-600° C. for 3-6 hours, sealing and storing the activated alumina, and drying the activated alumina for later use;

[0022] The adsorbent is filled in the chromatography column in a ratio of 1 / 3 activated alumina and 2 / 3 column chromatography silica gel.

[0023] As a preferred embodiment of the method for determining biomass tar components of the present invention, the organic solvent includes n-hexane, dichloromethane, acetone and tetrahydrofuran.

[0024] As a preferred embodiment of the method for determining biomass tar components of the present invention, the eluent includes petroleum ether, cyclohexane, n-heptane, benzene, toluene, ether, chloroform, ethyl acetate, n-butanol, acetone, ethanol, methanol and water.

[0025] As a preferred embodiment of the method for determining the components of biomass tar according to the present invention, the eluent for the aliphatic component is a mixture of one or two of n-hexane and n-heptane in proportion, the eluent for the aromatic component is a mixture of one or two of toluene and benzene in proportion, the eluent for the ester component is a mixture of one or two of ethyl acetate and chloroform in proportion, and the eluent for the polar component is a mixture of one or more of methanol, ethanol, acetone and n-butanol in proportion.

[0026] As a preferred embodiment of the method for determining the components of biomass tar of the present invention, the biomass tar includes wood tar, straw tar and shell tar.

[0027] Beneficial effects of the present invention:

[0028] (1) In order to overcome the problems existing in the existing biomass tar component analysis technology and the defects existing in the determination of tar composition by a single technology, the present invention provides a method for efficiently and accurately analyzing the components and contents of biomass tar by combining multiple technologies. Firstly, the separation characteristics of distillation method (DM) and chromatography column method (CM) are utilized. Biomass tar is used as raw material. DM is used to separate the biomass tar into tar fractions and asphaltene according to the boiling points of different components. The tar fractions are passed through a chromatography column with adsorption / desorption function to further separate the biomass tar into different groups of components, thereby achieving complete separation of the light components and heavy components of the biomass tar. Then, a gas chromatography-mass spectrometer (GC / MS) is used to analyze the biomass tar components. S) qualitatively and quantitatively analyze the components of the same family, and correct the GC-MS test results according to the final thermal weight loss rate of tar in TG; finally, according to the detection characteristics of infrared spectrometer (FT-IR), the heavy components (asphaltenes) that cannot be adsorbed by the chromatography column and detected by GC-MS after distillation of biomass tar are characterized by functional groups, and their structural types are further analyzed, so as to achieve accurate separation and quantitative analysis of biomass tar components; the comprehensive separation and accurate analysis of biomass tar components are achieved by the multi-technical combination of DM-CM-GC-MS-TG-FT-IR, which provides an important basis for the selection of biomass tar removal methods;

[0029] (2) The method of the present invention is carried out at low temperature and normal pressure, does not involve high temperature and high pressure, and has no safety issues. The eluent used can be recovered and reused after rotary evaporation, and the adsorbent can be reused after reactivation, which reduces the cost of the separation and analysis process, improves the recovery rate, and has a simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0031] Figure 1 Schematic diagram of biomass tar distillation in an embodiment of the present invention, including a condensing device (101), a fraction collecting device (102), a biomass tar containing device (103) and a heating device (104).

[0032] Figure 2 The system diagram of separating biomass tar components in an embodiment of the present invention includes an adsorption column (100), an air inlet sealing device (101), a spherical glass container (102), an auxiliary device (200), an air inlet device (300) and a collecting device (400).

[0033] Figure 3 The figure is a general process flow chart for separation and analysis of biomass tar components in an embodiment of the present invention.

[0034] Figure 4 This is a morphological comparison diagram of various fractions of biomass tar fraction separated by chromatography column in an embodiment of the present invention.

[0035] Figure 5 This is a diagram showing the qualitative and quantitative analysis results of the aliphatic group by GC / MS in the examples of the present invention.

[0036] Figure 6 This is a diagram showing the qualitative and quantitative analysis results of the aromatic groups by GC / MS in the examples of the present invention.

[0037] Figure 7 This is a diagram showing the qualitative and quantitative analysis results of GC / MS for ester groups in the examples of the present invention.

[0038] Figure 8 This is a diagram showing the qualitative and quantitative analysis results of polar compounds by GC / MS in an embodiment of the present invention.

[0039] Fig. 9 This is a diagram showing the FT-IR analysis results of biomass tar and asphaltene in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0043] In the present invention, the GC-MS instrument equipment (PerkinElmer Clarus 680-SQ 8T, USA); the Fourier transform infrared spectrometer equipment (Nicolet IS50, USA), and other raw materials and equipment are common commercial products.

[0044] Example 1

[0045] (1) Preliminary separation of biomass tar by distillation

[0046] The biomass tar sample after gasification of miscellaneous wood chips was placed in a 250mL oblique three-necked flask, equipped with a condenser, and subjected to gradient temperature distillation (5℃ / min). Four 500mL conical flasks were used to collect the fractions (asphaltene) after 0-120℃, 120-170℃, 170-220℃, 220-270℃, and 270℃, respectively.

[0047] The fractions before 220℃ are collected according to the continuous temperature increase. When collecting the fractions between 220-270℃, when a very small amount of fraction is seen distilling out, the temperature of the thermometer will automatically drop back and no longer rise. At this time, turn off the thermostat until the fraction returns to room temperature.

[0048] Finally, some solids will remain at the bottom of the distillation flask, which are the fractions after 270°C, namely asphaltene. After crushing it with a glass rod, it can be poured out and its characteristics can be analyzed.

[0049] The lower liquid (water) of the 0-120°C fraction was poured out, and the fractions in other temperature ranges were mixed and collectively called biomass tar fractions, which were stored for later use. The yield of each test is shown in the following table.

[0050] Table 1 Biomass fraction yields

[0051]

[0052] (2) Separation of biomass tar by chromatography column

[0053] Choice of adsorbent: Choose a combination of silica gel and alumina as the adsorbent, and activate them separately before use.

[0054] Silica gel was extracted with chloroform until it was no longer fluorescent. After the solvent evaporated, it was activated in a forced air drying oven at 130°C for 4.5 h, sealed with a double-layer sealing bag, and placed in a vacuum desiccator for later use.

[0055] The activated alumina was calcined in a muffle furnace with the temperature raised to 450°C at 20°C / min for 6 h and then sealed and stored in a desiccator for later use.

[0056] Selection of eluent: n-hexane, toluene, ethyl acetate and methanol are selected as eluents for aliphatics (AL), aromatics (AR), esters (ES) and polar substances (PO).

[0057] Column loading: Fix the chromatography column with a 2mm thick sand core on the iron frame with a cross and a condenser tube rack, add 1 / 3 activated alumina and n-hexane solution to the column and start vibrating along the length of the column and gently tap the outside of the chromatography column with an ear bulb until the bubbles are discharged; continue to vibrate the column, add 2 / 3 of the column chromatography silica gel and n-hexane solution, continue to vibrate to ensure the column layer is firm, and the column loading is complete.

[0058] Sampling: Take 2g of biomass tar fraction and put it into a 25ml beaker. Add 10ml of n-hexane to dilute and dissolve the sample and continue to heat in a constant temperature shaking water bath to assist dissolution.

[0059] Then add n-hexane to the top of the column to completely wet the adsorbent; when the liquid level of 10 ml of n-hexane reaches the top of the silica gel, transfer the sample solution from the beaker to the 100 ml spherical glass container on the top of the column; wash the beaker with n-hexane three times in a row and add the washing solution to the top of the column, and wash the top of the column three times with n-hexane.

[0060] Elution:

[0061] First, add sufficient n-hexane to the top of the column, apply pressure and adjust the flow rate to collect the eluent; when the last remaining n-hexane level reaches the top of the silica gel, release the gas pressure and add sufficient toluene, while adjusting the rate of the effluent to the same;

[0062] After all AL components are washed out by using a color developer, use n-hexane to rinse the lower end of the chromatographic column and mark the collected liquid as n-hexane eluent (AL component);

[0063] Second, when the last remaining toluene reaches the top of the silica gel, release the gas pressure and add a sufficient amount of ethyl acetate, repeat the above steps; after all the AR components are washed out by toluene using the refractive index measurement, rinse the lower end of the chromatographic column with toluene, and mark the collected liquid as toluene eluent (AR component);

[0064] Third, when the last residue of ethyl acetate reaches the top of the silica gel, release the gas pressure, add a sufficient amount of methanol, and repeat the above steps; similarly, use the refractive index to measure that after all the ES components are washed out of ethyl acetate, rinse the lower end of the chromatographic column with ethyl acetate, and mark the collected liquid as ethyl acetate eluent (ES component);

[0065] Fourth, when the last remaining methanol reaches the bottom of the silica gel, the PO component is completely washed out by methanol using the same refractive index measurement, and then the lower end of the chromatographic column is rinsed with methanol, and the collected liquid is marked as methanol eluent (PO component); elution is completed.

[0066] Recovery rate calculation: Evaporate AL, AR, ES, and PO eluents in a rotary evaporator according to the boiling points of the components of different families. When all the solvents are completely evaporated, take out four weighing bottles and let them cool naturally to room temperature. Dry the outside to remove moisture ( Figure 4 );

[0067] They were weighed, and the mass fractions of the recovered AL, AR, ES and PO components from repeated experiments are shown in Table 2.

[0068] Table 2 Mass percentage and total recovery rate of each group

[0069]

[0070] (3) GC / MS analysis of biomass tar components

[0071] Since each group has similarities in structure and properties, different GC-MS methods can be used to determine the composition and content of AL, AR, ES and PO groups.

[0072] The specific conditions are as follows: HP-5MS chromatographic column (30m×0.05μm×0.32nm(i,d)) type capillary column, and the GC detection conditions of different family components are shown in Table 3.

[0073] The mass spectrometer interface temperature was 270°C, the ion source temperature was 220°C, the quadrupole temperature was 100°C, the mass spectrometer scanning range was 30-500amv, the injection method was fractionation injection, the fractionation ratio was 20:1, the column head pressure was 15psi, and the injection volume was 0.1μL; the analysis structure was as follows Figures 5 to 8 .Depend on Figure 5-8 It can be seen that this method can effectively analyze the material composition and content of different groups of components in tar.

[0074] from Figure 5 It can be seen that n-hexane has a strong solubility for normal alkanes, accounting for up to 48.44%; olefins account for 12.13%. Non-normal alkanes and cycloalkanes account for 11.11% and 11.36% respectively. Cycloalkanes generally have larger molecular weights, and the carbon number is mainly distributed in C 17 -C 20 In addition, AL also contains 23.04% of monocyclic aromatic hydrocarbons. These aromatic hydrocarbons are eluted into the AL component by n-hexane because of their long-chain aliphatic side chains as benzene ring substituents. The carbon numbers of their side chains are mainly distributed in C4-C8 and C 15 -C 20 between.

[0075] GC / MS total ion current and composition distribution of AR components are shown in Figure 6 Among the components, aromatic hydrocarbons accounted for 92.68%, mainly 4-ring or less aromatic hydrocarbons; among them, three-ring substances accounted for 40.14%, mainly in the form of phenanthrene, monomethylphenanthrene, dimethylphenanthrene and trimethylphenanthrene; the second largest component was bicyclic aromatic hydrocarbons, accounting for 33.25%, and its main existence forms were alkyl-substituted naphthalene in various forms except naphthalene; the third largest component was monocyclic aromatic hydrocarbons, with a content of 10.94%, mainly in the form of benzene and its derivatives, and the carbon number distribution was mainly in the range of C8-C 13 Among the tetracyclic aromatic hydrocarbons in the AR component, only one compound is pyrene, accounting for 8.34%. In addition, due to the strength of free radical activity, substances with hydrogenated naphthalene rings and aromatic ring structures in this component are also eluted by toluene during column chromatography separation. Therefore, column chromatography combined with GC-MS has a good effect on the determination of the content of the main components of tar.

[0076] GC / MS total ion current and composition distribution of ES components are shown in Figure 7 As shown in the figure, oxygenated compounds of monocyclic aromatic hydrocarbons were detected in the ES components, mainly furan, phenols, benzylamine, alcohols and other oxygenated compounds. Among them, phenolic substances accounted for the highest proportion, accounting for 68.66%, mainly monocyclic phenolic substances, and the carbon number distribution was mainly in the range of C6-C 11 The second is benzylamine, accounting for 11.27%, and the carbon number distribution is mainly C9-C 12 The third component is monocyclic alcohols, accounting for 3.02%, and the carbon number distribution is mainly between C9-C 10 In addition, there are other monocyclic aromatic oxygen-containing compounds. Due to the high oxygen content of biomass raw materials, tar contains more oxygen-containing compounds. It is also proved that column chromatography combined with GC-MS can effectively separate different groups of components in tar.

[0077] The GC / MS total ion current of PO components is shown in Figure 8 The aromatic hydrocarbons detected in this component are oxygen-containing compounds of complex aromatic hydrocarbons, and the carbon number distribution is mainly in the range of C6-C 11 The second is benzylamine, accounting for 11.27%, and the carbon number distribution is mainly C 10 -C 28 Because the components of this component are complex, in the pyrolysis of biomass tar, this part of the components can be called stubborn tar or form carbon deposits, which is an important reason affecting tar reforming and biomass utilization.

[0078] Table 3 Analysis of temperature changes of tar groups

[0079]

[0080] Example 2

[0081] Generally, asphaltene is a mixture of various polymers with very large molecular weight, which is difficult to separate and analyze using the general GC-MS method.

[0082] Therefore, Fourier transform infrared spectrometer was used to determine the functional groups in asphaltene, and the test range was from 4500-400 cm -1 and compared with the original biomass tar, the analysis results are as follows Fig. 9 .

[0083] Depend on Fig. 9 It can be seen that biomass tar is between 4000 and 500 cm -1 The peaks in the wavenumber region do not exist independently, but are the overlapping phenomenon of multiple peaks. The entire infrared spectrum can be divided into five parts, which are four types of functional groups: wavenumbers between 3500 and 300 cm -1 -OH stretching vibration and CO stretching vibration in alcohols and phenols, 3000~2700cm -1 CH absorption peak of fat, 1800~1550cm -1 and 1200~1000cm -1 It is the absorption peak of oxygen-containing functional groups, 1550~1300cm -1 and 900~700cm -1 It is the aromatic CH absorption peak.

[0084] However, except for the obvious absorption peaks of asphaltene at positions 1, 2, 3, and 4, the other absorption peaks are blurred or even disappear. This indicates that most of the residues after distillation are heavy aliphatic components, namely, the antisymmetric and symmetric stretching vibrations of saturated alkyl groups -CH3 and -CH2 in cycloalkanes or aliphatics, and other light components are distilled out after distillation, which further proves the reliability of the distillation experimental data.

[0085] Example 3

[0086] The distillation method refers to Example 1 to explore the effects of different parameters for preliminary separation of biomass tar on the yield of biomass fractions, see Table 4.

[0087] Table 4

[0088] Serial number Test 1 Test 2 Test 3 Collection fraction temperature range (℃) 100～250 140～240 120～260 Biomass fraction yield (%) 70.56 56.03 76.39

[0089] From Table 4, which shows the yield of biomass tar fractions obtained from different experiments, it can be seen that the fraction yield between 100-250°C in Experiment 1 is 70.56%, and when Experiment 2 narrows the temperature range to between 140-240°C, the tar fraction yield (56.03%) drops significantly by 14.53%. This is mainly due to the fact that some light components between 100-140°C and some heavy components between 240-260°C are not distilled out. This shows that the choice of fraction temperature plays a decisive role in whether the fraction is completely distilled out.

[0090] Furthermore, when the temperature range was expanded to 120-260°C in Experiment 3, the tar fraction yield was significantly increased to 76.39%, which was 5.83% higher than that in Experiment 1. This was mainly due to the fractions of some heavy components between 250-260°C. Therefore, the selection of the temperature range for the initial separation of biomass tar by distillation is particularly important.

[0091] Example 4

[0092] Under the conditions of Example 1, the effects of different elution adsorbents on the total yield of each group of components were investigated. Other conditions were the same as in Example 1, see Tables 5 and 6.

[0093] Table 5

[0094]

[0095] The total recovery rate is shown in Table 6.

[0096] Table 6

[0097] Experiment No. Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Total recovery rate (%) 96.45 60.25 66.33 40.57 20.14 65.00

[0098] As can be seen from Table 6, when the ratio of activated alumina to silica gel is 1:3, the total recovery rate of each group of components is the highest at 96.45%; as in Experiment 5, when the ratio of activated alumina is increased and the ratio of silica gel is reduced, the total recovery rate of each group of components decreases significantly, which shows that silica gel and its proportion in the adsorbent ratio are the main adsorption effects. Other experiments also illustrate this point. Therefore, the optimization and ratio of adsorbents are extremely important.

[0099] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for determining biomass tar components, characterized in that: include, The biomass tar is distilled to obtain a tar fraction and asphaltene, wherein the boiling point range of the distillation is divided into 0-120°C, 120-170°C, 170-220°C, 220-270°C, and 270-330°C by step-by-step heating, the fraction collected in the temperature range of 120-270°C is the tar fraction, and the fraction collected in the temperature range of 270-330°C is the asphaltene; The tar fraction is completely dissolved using n-hexane to obtain a tar solution; Pour the tar solution into the liquid storage ball of the chromatography column, select the eluent in the order of polarity from small to large to elute through the chromatography column, collect the eluent according to the group components, and analyze whether the elution is complete by combining the color developer and the refractive index, and obtain the aliphatic component, aromatic component, ester component and polar component respectively; The eluent for the aliphatic component is one or two of n-hexane and n-heptane mixed in proportion, the eluent for the aromatic component is one or two of toluene and benzene mixed in proportion, the eluent for the ester component is one or two of ethyl acetate and chloroform mixed in proportion, and the eluent for the polar component is one or more of methanol, ethanol, acetone, and n-butanol mixed in proportion; Wherein, the chromatography column comprises activating the adsorbent and then packing the chromatography column by a wet method; The adsorbent is column chromatography silica gel and activated alumina, wherein the column chromatography silica gel is activated by extracting the silica gel with chloroform until it does not emit fluorescence, activating it in a forced air drying oven at 105-150°C for 3-6 hours after the solvent evaporates, and then sealing it with a multi-layer sealing bag and placing it in a vacuum dryer for standby use; the activation method of activated alumina is to roast the activated alumina in a muffle furnace at 450-600°C for 3-6 hours, and then seal it for storage, dry it for standby use, and the filling ratio of the adsorbent in the chromatography column is activated alumina: column chromatography silica gel = 1:3; The composition and content of aliphatic components, aromatic components, ester components and polar components were determined by GC-MS method; In the case of the relative contents of each component determined by the GC-MS method, the final weight loss rate determined by the thermogravimetric analyzer is multiplied by the relative content value of each component determined by the gas chromatography-mass spectrometry to obtain the accurate content of each component in the tar; The functional groups in asphaltenes were determined by Fourier transform infrared spectroscopy to analyze the composition and content of biomass tar; The biomass tar includes wood tar, straw tar and shell tar.

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