Removal of contaminants from coal tar-derived crude phenols

Abstract

A process for removing contaminants from coal-derived phenols is described. The process combines an extraction process with at least two adsorption zones containing adsorbents. Liquid-liquid and acid-base extraction processes may be used. The adsorbents may be clays and / or zeolites. The process may be used to reduce organic nitrogen and sulfur compounds to levels below 10 ppmw and produce a colorless product.

Description

[Background technology]

[0001] Low- and medium-temperature coal tar contains significant amounts of valuable phenols, especially in fractions below 300°C. Phenol mixtures (crude phenols) can be extracted from the fractions using a variety of physical and chemical methods, including extraction with aqueous sodium hydroxide followed by neutralization with strong inorganic acids, selective solvent extraction, and ion-exchange resin adsorption.

[0002]

[0002] Low- and medium-temperature coal tar typically has a nitrogen and sulfur content of less than 1.0%. The extraction methods described above are effective in removing a portion of the organosulfur and nitrogen compounds from crude phenols. Traces of organosulfur and nitrogen compounds remaining in crude phenols must be removed because they act as catalyst poisons in downstream upgrading processes, where low-value phenolic compounds are converted to higher-value phenols and aromatics, for example, by catalytic dealkylation and transalkylation.

[0003]

[0003] Industrially, hydrotreating is the most commonly used method for removing organic nitrogen and sulfur from oil. However, hydrotreating is not a selective process for nitrogen and sulfur removal. In addition to hydrodenitrogenation (HDN) and hydrodesulfurization (HDS), other processes, including hydrodemetallization (HDM), hydrodeoxygenation (HDO), hydrodearomatization (HDA), and olefin saturation, also occur in parallel. Of the most abundant heteroatoms (S, N, and O) in oil, nitrogen is the most difficult to remove by hydrotreating. In addition, both HDO and HDA destroy phenols. Because nitrogen is the most difficult to remove and hydrotreating destroys phenols, it is recognized as a poor method for removing nitrogen-based contaminants from phenols. "Simultaneous hydrodenitrogenation and hydrodeoxygenation of model compounds in a trickle bed reactor," Journal of Catalysis (1983), 81(2):335-346; "Hydrorefining Coal-Tar Naphthalene: Hydrogenolysis over cobalt molybdate catalyst removes impurities containing sulfur, oxygen, and nitrogen and yields a refined product of high purity," Industrial and Engineering Chemistry, Vol. 53, No. 12, 1961, pp. 993-996; "Hydrotreatment of model compounds with catalysts of NiW / Al2O3 and NiWP / Al2O3 to simulate low-temperature coal tar oil," RSC Adv., 2017, 7, pp. 545-512. Additionally, catalytic hydrodesulfurization (HDS) is not efficient for removing sulfur contaminants from phenols. This is because HDS is inhibited by phenols such as cresol."Catalytic hydrodeoxygenation: II. Interactions between catalytic hydrodeoxygenation of m-cresol and hydrodesulfurization of benzothiophene and dibenzothiophene", Journal of Catalysis (1983), 80(1): pp. 65-75.

[0004] Other processes have been used to remove sulfur and / or nitrogen. For example, in GB 738177, phenols in coal tar distillates are extracted with aqueous alkali, followed by purification of the resulting phenolate solution by treatment with one or more of the following adsorbents: bleaching earths made from clays of the montmorillonite group (fuller's earth, bentonite, nontronite, beidellite, hectorite (Mg-bentonite)); alumina; basic oxides, hydroxides, or carbonates of either Fe, Mg, or Ca; and a "caustic slurry" obtained by heating the phenolate alkali residue with lime. After neutralization with acid, especially CO2, the phenols are obtained as a clear liquid with an acceptable odor. Removal of nitrogen-based contaminants is not addressed.

[0005] Another process is described in US 2,247,523. Phenols were extracted from coal tar distillate into aqueous sodium hydroxide. This was followed by a step of treating the resulting phenolate solution with an adsorbent such as fuller's earth, diatomaceous earth, or activated carbon. The phenolate solution was then treated with an acid such as HCl, H2SO4, or CO2 to liberate the phenols. The phenols were still colored, or at least darkened, especially when left standing in light, and in some cases had an unpleasant odor. The odor and color of the phenols were finally improved by the addition of a small amount of formaldehyde and subsequent vacuum distillation. The removal of nitrogen and sulfur contaminants was not addressed.

[0006]

[0006] US 2,744,938 describes a process for decolorizing alkylphenols discolored by oxidation. The process involves contacting a solution of alkylphenols in a solvent with an adsorbent selected from the group consisting of activated carbon, alumina, clay, and silica gel in the presence of hydrogen at superatmospheric pressure and at a temperature of about 40 to about 150°C. The process does not address the removal of nitrogen and sulfur contaminants.

[0007]

[0007] CN102188962 discloses a catalytic adsorbent for purifying coal-based phenols. The catalytic adsorbent contains the following active components: 0-99% by weight kaolinite, 15-99% by weight active clay, 0-20% by weight sepiolite, 0-45% by weight diatomaceous earth, 0-80% by weight mordenite, and 0-99% by weight ZSM zeolite. The best results obtained were a reduction in sulfur content from approximately 1000 ppm to 27 ppm (97.3% sulfur removal). No mention is made of nitrogen reduction. Summary of the Invention

[0008]

[0008] Therefore, there is a need for a process that can recover crude phenols from coal tar, remove nitrogen and sulfur contaminants from the crude phenols, and efficiently upgrade the crude phenols. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating one embodiment of the process of the present invention. [Figure 2]

[0010] GC-NCD chromatogram of Sample 1 before adsorption. [Figure 3A]

[0011] GC-NCD chromatogram of Sample 1 after adsorption with bentonite-HCl. [Figure 3B]

[0012] GC-NCD chromatogram of Sample 1 after adsorption using HZSM-5 zeolite. [Figure 4A]

[0013] GC-NCD chromatogram of Sample 1 after adsorption using sepiolite. [Figure 4B]

[0014] GC-NCD chromatogram of Sample 1 after adsorption using HZSM-5. [Figure 5A]

[0015] GC-NCD chromatogram of Sample 1 after adsorption using sepiolite. [Figure 5B]

[0016] GC-NCD chromatogram of Sample 1 after adsorption with bentonite-HCl. [Figure 6A]

[0017] GC-NCD chromatogram of Sample 1 after adsorption with fuller's earth. [Figure 6B]

[0018] GC-NCD chromatogram of Sample 1 after adsorption with bentonite-HCl. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0019] The process of the present invention provides a method for removing contaminants from coal-derived phenols. Nitrogen compounds have very low reactivity compared to oxygen and sulfur compounds. Nitrogen compounds also strongly adsorb onto the active sites of the catalyst, interfering with the crude phenols upgrading process.

[0011]

[0020] It has been discovered that by combining an extraction process followed by an adsorption process, cleaner crude phenols with sulfur and nitrogen levels below 100 ppmw, and in some cases below 10 ppmw, can be prepared from coal-derived feedstreams.

[0012]

[0021] Coal-derived feedstreams, such as low-temperature coal tar, medium-temperature coal tar, high-temperature coal tar, cresylic acid, or crude phenol mixtures, contain phenol, alkylphenols (e.g., methylphenols (cresols), ethylphenols, dimethylphenols (xylenols), propylphenols, butylphenols, and methylethylphenols), and heavy alkylphenols (e.g., indanol and naphthol). Coal tar is produced by the carbonization and gasification process of coal and is classified based on the temperatures used in the process: 400–600°C (low temperature), 600–1000°C (medium temperature), and above 1000°C (high temperature). Cresylic acid is a general term referring to the combination of phenol and alkylphenols and can be obtained, for example, from either coal or petroleum processing. Crude phenol mixtures can be obtained from coal tar oil processing and the purification of phenol-containing wastes from, for example, coke ovens, low-temperature carbonization, and hydrogenation plants. The composition of the feedstream varies depending on its source.

[0013]

[0022] The coal-derived feed stream can be separated into various streams. Suitable separation processes include, but are not limited to, distillation, acid / base extraction, solvent extraction, etc. The crude phenol stream may comprise a portion of the coal-derived feed stream. The crude phenol stream may comprise a portion of one or more of a low-temperature coal tar stream, a medium-temperature coal tar stream, a high-temperature coal tar stream, a cresylic acid stream, or a crude phenol mixture. The crude phenol stream may have a boiling point of about 300°C or less. For example, the crude phenol stream may comprise a portion of a low-temperature or medium-temperature coal tar distillate stream, e.g., having a boiling point of about 300°C or less.

[0014]

[0023] The crude phenol stream is subjected to an extraction process to produce an extraction effluent stream containing minimal impurities (organic nitrogen, organic sulfur, and neutral oils), facilitating the subsequent adsorption process. Liquid-liquid extraction may be used to effectively separate phenolic compounds from coal tar distillates (e.g., below about 300°C). Suitable liquid-liquid extraction processes include, but are not limited to, acid-base liquid extraction and aqueous methanol liquid extraction. While aqueous methanol extraction is safer and easier to operate, acid / base liquid extraction has been found to be more effective for removing nitrogen and sulfur-based contaminants. Other liquids may also be used for extraction, including, but not limited to, ethanol, propanol, glycols, alcoholamines, etc. From the perspective of nitrogen and / or sulfur-based contaminant removal, these two extraction methods are superior to hydrotreating because they do not destroy phenols.

[0015]

[0024] In some embodiments, the acid-base extraction process reduces organic nitrogen in the coal tar distillate stream to less than 100 ppmw and organic sulfur to less than 100 ppmw, or less than 50 ppmw. The coal tar distillate stream or its solution in an aromatic solvent (e.g., toluene, benzene, xylene) is extracted multiple times with a basic aqueous solution (e.g., 3 M aqueous sodium hydroxide). The combined extracts are then washed with an 80:20 mixture of hexane and dichloromethane to remove residual neutral and alkaline coal tar components. After acidification with an acid solution (e.g., hydrochloric acid, sulfuric acid), the crude phenol is recovered as an oil or extracted multiple times with dichloromethane to increase phenol recovery. The solvent is removed, yielding crude phenol as an oil.

[0016]

[0025] The extraction process is followed by an adsorption process to remove remaining trace, refractory nitrogen and sulfur contaminants to obtain the low contaminant levels required for further processing of the stream. It has been discovered that improved adsorption can be achieved by using two or more adsorbent zones. At least two different adsorbent zones can be provided. The first adsorbent zone contains clay and the second adsorbent zone contains zeolite. The order of the adsorbent zones can be interchanged.

[0017]

[0026] The adsorption process may be carried out in a shaker or column at temperatures ranging from room temperature to about 90° C., at atmospheric or superatmospheric pressure, for a period of several hours to several days.

[0027] The first adsorbent zone comprises about 20% or more, or about 30% or more, or about 40% or more, or about 50% or more, or about 60% or more, or about 70% or more, or about 80% or more, or about 90% or more, or about 95% or more of one or more clays. Suitable clays include, but are not limited to, bentonite, HCl-activated bentonite, silica gel, sepiolite, and fuller's earth.

[0018]

[0028] The second adsorbent zone comprises about 20% or more, or about 30% or more, or about 40% or more, or about 50% or more, or about 60% or more, or about 70% or more, or about 80% or more, or about 90% or more, or about 95% or more of one or more zeolites. Suitable zeolites include, but are not limited to, HZSM-5 zeolite and HBETA zeolite.

[0019]

[0029] A third (or more) adsorbent zone may be provided containing a third adsorbent. The third adsorbent may comprise one or more clays and / or one or more zeolites. The third adsorbent zone may comprise a different adsorbent from the first adsorbent and / or the second adsorbent. Alternatively, the third adsorbent may be the same as either the first or second adsorbent. For example, in one embodiment, the clay of the first adsorbent may comprise one or more of bentonite and HCl-activated bentonite, the zeolite of the second adsorbent may comprise one or more of HZSM-5 zeolite and HBETA zeolite, and the third adsorbent may comprise one or more of HZSM-5 zeolite, HBETA zeolite, silica gel, sepiolite, and fuller's earth. In one example, the first adsorbent clay comprises HCl-activated bentonite, the second adsorbent zeolite comprises HZSM-5 zeolite, and the third adsorbent comprises one or more of fuller's earth or sepiolite.

[0020]

[0030] The designations "first" and "second" (and "third or more") adsorbents are merely for distinguishing purposes. They are not meant to identify which is first in the process. In other words, the first adsorbent can be upstream or downstream of the second adsorbent. The third adsorbent can be upstream of both the first and second adsorbents, downstream of both, or somewhere in between (in all cases, the first adsorbent is upstream or downstream of the second adsorbent).

[0021]

[0031] The first and second adsorbent zones may be located in a single vessel or in different vessels. When the first and second adsorbent zones are located in the same vessel, the first adsorbent zone may be located above the second adsorbent zone, and the second adsorbent zone may be located above the first adsorbent zone.

[0022]

[0032] Alternatively, when the first and second adsorbent zones are located in the same vessel, if a third adsorbent zone is present, the third adsorbent zone may be located in the same vessel as the first adsorbent zone and / or the second adsorbent zone, or in a separate vessel.

[0023]

[0033] Alternatively, there can be one adsorbent zone containing a mixture of two or more adsorbents, the adsorbent including one of a clay and a zeolite.

[0034] The first adsorption zone and / or the second adsorption zone may comprise at least one of a fixed bed, a fluidized bed, a moving bed, and a rotating bed.

[0024]

[0035] The crude phenol stream can be passed through the adsorbent bed in either upflow or downflow fashion.

[0036] The extract effluent may have less than 200 ppmw, or less than 175 ppmw, or less than 150 ppmw, or less than 125 ppmw, or less than 100 ppmw, or less than 75 ppmw, or less than 50 ppmw of organic sulfur compounds. The extract effluent may have less than 1500 ppmw, or less than 1250 ppmw, or less than 1000 ppmw, or less than 750 ppmw, or less than 500 ppmw, or less than 250 ppmw, or less than 100 ppmw of organic nitrogen compounds. The organic sulfur content is measured using a nitrogen and sulfur analyzer. Sulfur analysis is performed according to ASTM D5453-16 using an Elementar trace SN cube (available from Elementar Analysensysteme GmbH, Langenselbold, Germany). The organic nitrogen content is measured using a nitrogen and sulfur analyzer. Nitrogen analysis is performed according to ASTM D4629-17 using an Elementar trace SN cube.

[0025]

[0037] The adsorption effluent may have less than 100 ppmw, or less than 75 ppmw, or less than 50 ppmw, or less than 40 ppmw, or less than 30 ppmw, or less than 25 ppmw, or less than 20 ppmw, or less than 15 ppmw, or less than 10 ppmw of organic sulfur compounds. The adsorption effluent may have less than 100 ppmw, or less than 75 ppmw, or less than 50 ppmw, or less than 40 ppmw, or less than 30 ppmw, or less than 25 ppmw, or less than 20 ppmw, or less than 15 ppmw, or less than 10 ppmw of organic nitrogen compounds. Because phenolic compounds themselves are colorless, the presence of color in the crude phenol stream is evidence of nitrogen and / or sulfur contamination in the crude phenol. The adsorption effluent may be colorless using visual inspection, indicating reduced levels of organic nitrogen and / or organic sulfur compounds.

[0026]

[0038] An adsorption process (following extraction) in which the first adsorbent was HCl-activated bentonite, the second adsorbent was H-ZSM5, and the third adsorbent was fuller's earth produced a colorless adsorbent effluent. In contrast, a mixed bed of the same three adsorbents did not completely eliminate the color of the adsorbent effluent. However, there may be downstream processes in which this level of nitrogen and sulfur contaminants is acceptable.

[0027]

[0039] The process may result in phenol recovery rates of 75% or greater, or 80% or greater, or 85% or greater, or 90% or greater, or 92% or greater, or 93% or greater, or 94% or greater, or 95% or greater, which may be compared to hydrotreating processes in which more than 90% of the phenols are destroyed.

[0028]

[0040] The recovery rate of phenols is calculated by the following formula:

[0029]

number

[0030] It is calculated by:

[0041] For example, no obvious compositional changes were observed after the three-zone adsorption process using bentonite-HCl / H-ZSM5 / fuller's earth.GC-MS analysis was used to measure the changes in phenolic composition before and after the adsorption process.

[0031]

[0042] Figure 1 illustrates a process 100. A coal tar or crude phenol feed stream 105 is separated into one or more streams in one or more distillation columns 110. For example, the coal tar or crude phenol feed stream 105 may be divided into a stream 115 having a boiling point below about 150°C, a crude phenol stream 120 having a boiling point between about 150°C and about 300°C, and a stream 125 having a boiling point above 300°C. Those skilled in the art will recognize that other divisions of the coal tar or crude phenol feed stream 105 are possible.

[0032]

[0043] Crude phenol stream 120 contains a majority of the phenolic compounds in the coal tar or crude phenol feed stream 105. Crude phenol stream 120 is sent to one or more extraction columns 130. A portion of the organosulfur and nitrogen compounds are removed from crude phenol stream 120, resulting in an extraction effluent stream 135 having reduced levels of organosulfur and nitrogen compounds relative to the incoming crude phenol stream 120, and an oil-containing stream 140 having reduced levels of phenols and containing the organosulfur and nitrogen compounds removed from crude phenol stream 120. The extraction process can be an acid-base liquid extraction process or an aqueous methanol liquid extraction process.

[0033]

[0044] Extract effluent 135 is sent to adsorption unit 145, which includes first and second adsorption zones containing first and second adsorbents. Adsorption unit 145 may include one or more adsorption vessels, each containing one or more adsorption zones, as known in the art. The adsorption unit may also include three or more adsorption zones, as described above. An additional portion of the organic sulfur and nitrogen compounds is removed from extract effluent 135 in adsorption unit 145, resulting in adsorbed effluent 150, which has reduced levels of organic sulfur and nitrogen compounds compared to the incoming extract effluent 135.

[0034]

[0045] The adsorbed effluent stream 150 may be sent for downstream phenolic separation and / or further processing.

[0046] The selection of the adsorbent combination was based on knowledge gained from adsorbent selectivity studies of coal tar. Adsorption was measured using gas chromatography-nitrogen chemiluminescence detection (GC-NCD). NCD is a nitrogen-specific detection tool; only N-containing compounds appear in the chromatogram, making it highly sensitive and useful for detecting residual nitrogen-based contaminants in coal tar samples.

[0035]

[0047] Although no single adsorbent was found to be efficient enough to reduce contaminants to the desired level, when the extraction effluent was subjected to different single adsorbents in parallel under the same experimental conditions, comparison of the resulting GC-NCD chromatograms provided valuable information on the nitrogen contaminant adsorption selectivity of these adsorbents.

[0036]

[0048] For example, Figure 2 shows the GC-NCD chromatogram of Sample 1, the effluent from the acid-base extraction process, before adsorption.

[0049] Figures 3A and 3B show the GC-NCD chromatograms of Sample 1 after adsorption using bentonite-HCl (same material as in Figures 5B and 6B, but on a different scale) and HZSM-5 zeolite (same material as in Figure 4B, but on a different scale), respectively. As can be seen, the remaining peaks are different, which means that the two adsorbents adsorb different nitrogen molecules.

[0037]

[0050] Figures 4A and 4B show the GC-NCD chromatograms of Sample 1 after adsorption using sepiolite (same material and scale as in Figure 5A) and HZSM-5 zeolite (same material as in Figure 3B, but on a different scale), respectively. The remaining peaks are different for the two adsorbents, indicating that these adsorbents adsorb different nitrogen molecules.

[0038]

[0051] Figures 5A and 5B show the GC-NCD chromatograms of Sample 1 after adsorption using sepiolite (same material and scale as in Figure 4A) and bentonite-HCl (same material as in Figures 3A and 6B, but different scales), respectively. The differences in the remaining peaks indicate that these adsorbents adsorb different nitrogen molecules.

[0039]

[0052] Figures 6A and 6B show the GC-NCD chromatograms of Sample 1 after adsorption using fuller's earth and bentonite-HCl (the same materials as in Figures 3A and 5B, but on different scales), respectively. The differences in the remaining peaks indicate that these adsorbents adsorb different nitrogen molecules.

[0040]

[0053] Experiments with effluent from an aqueous methanol extraction process yielded similar results: different adsorbents adsorbed different nitrogen molecules.

[0054] The adsorbent selectivity study showed that different adsorbents adsorb different nitrogen compounds from the extraction effluent. Therefore, the performance of the adsorbents is complementary in removing nitrogen-based pollutants, and when adsorbents are used in combination, a synergistic effect is produced.

[0041]

[0055] From this, it is expected that different adsorbents will adsorb different sulfur molecules.

[0056] For convenience, the process will be described below as it applies to coal tar, but those skilled in the art will recognize that the process may also be used with other coal-derived liquids, including, but not limited to, liquids produced by coal liquefaction processes. [Example]

[0042] Example 1

[0057] Extraction Process

[0058] A portion of the coal tar fraction (150-250°C, initial N level 4200 ppmw, S level 700 ppmw) was subjected to an acid / base extraction process. The fraction (2.3 kg) was dissolved in 5.6 kg of toluene. The resulting toluene solution was extracted three times with 3.0 M aqueous NaOH (8.6 kg, 6.3 kg, and 4.0 kg) at room temperature. The combined aqueous phase was extracted twice with hexane / dichloromethane (4:1 v / v) (2.6 kg each) to remove residual neutral and alkaline components. 6 M hydrochloric acid (9.5 kg) was slowly added to the aqueous phase with stirring at 10°C to acidify it to pH 1.0. The acidified aqueous phase was extracted three times with dichloromethane (5.3 kg each). The combined dichloromethane solution was washed twice with distilled (DI) water (0.5 L each) to remove residual salts. Dichloromethane and residual water were removed by rotary evaporation to give a crude phenol stream (1.25 kg, 55 wt % yield).

[0043]

[0059] The effluent from the acid / base extraction process had 96 ppmw nitrogen and 47 ppmw sulfur (Sample 1).

[0060] Another portion of the same fraction was subjected to an aqueous methanol extraction process. The fraction (1.0 kg) was dissolved in 4.0 L of methanol, followed by the addition of 1.7 L of DI water. The volume ratio of methanol to water was 70:30. A cloudy mixture resulted due to the insolubility of less polar components (non-phenolic compounds). The cloudy mixture in the aqueous methanol solution was extracted three times with hexane (1.0 L each time). The methanol and water were removed by rotary evaporation to obtain a crude phenolic oil. The crude phenolic oil was further extracted twice with 1.0 M hydrochloric acid (200 mL each time) to remove alkaline organic nitrogen compounds. After rotary evaporation at 50°C under vacuum (10 mmHg) for 4 hours to remove residual water, a crude phenolic stream (0.56 kg, 52 wt. % yield) was obtained.

[0044]

[0061] The effluent from the aqueous methanol extraction process had 1468 ppmw nitrogen and 174 ppmw sulfur (Sample 2).

[0045] Example 2

[0062] Adsorption Process

[0063] Samples 1 and 2 were then subjected to adsorption using various adsorbents.

[0046]

[0064] Adsorbent pretreatment:

[0065] Acid-activated bentonite (bentonite-HCl):

[0066] To 40.0 g of bentonite clay was added 80 mL of 3.0 M hydrochloric acid (HCl). The resulting mixture was heated at 70 °C for 12 hours with gentle stirring. After filtration, the collected solid was dried at 105 °C for 12 hours. The dried HCl-treated bentonite was crushed to a 30-50 mesh size before use. The dried bentonite was stored under nitrogen.

[0047]

[0067] Zeolite adsorbents (HZSM-5, HBETA, etc.) were sized to 30–50 mesh and calcined at 540 °C for 3 h. All other adsorbents were pretreated at 150 °C for 1 h before use to remove adsorbed compounds.

[0048]

[0068] Adsorption Process 1: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, sepiolite, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a colorless oil with N and S levels of 5 ppmw and 6 ppmw, respectively, was obtained.

[0049]

[0069] Adsorption Process 2: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, fuller's earth, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a colorless oil with N and S levels of 8 ppmw and 6 ppmw, respectively, was obtained. The phenol recovery rate was 93%.

[0050]

[0070] Adsorption Process 3: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of a mixture of bentonite-HCl, HZSM-5 (Zeolyst, CBV3024E), and fuller's earth (5 g each). The resulting mixture was shaken for 2-24 hours. After filtering to remove the adsorbent mixture and removing the solvent, a light brown oil was obtained with N and S levels of 42 ppmw and 10 ppmw, respectively. The phenol recovery was 92%.

[0051]

[0071] Adsorption Process 4: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, HBETA (Clariant, HCZB150), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a pale yellow oil with N and S levels of 18 ppmw and 9 ppmw, respectively, was obtained.

[0052]

[0072] Adsorption Process 5: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent and removing the solvent, a light brown oil was obtained with N and S levels of 29 ppmw and 15 ppmw, respectively. The phenol recovery was 95%.

[0053]

[0073] Adsorption Process 6: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent and removing the solvent, a light brown oil with N and S levels of 62 ppmw and 22 ppmw, respectively, was obtained.

[0054]

[0074] Adsorption Process 7: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, silica gel, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a light brown oil with N and S levels of 42 ppmw and 12 ppmw, respectively, was obtained.

[0055]

[0075] Adsorption Process 8: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, silica gel, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, 5.0 g of a fourth adsorbent, fuller's earth, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, a colorless oil with N and S levels of 15 ppmw and 4 ppmw, respectively, was obtained. The phenol recovery rate was 93%.

[0056]

[0076] Adsorption Process 9: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, HBETA (Clariant, HCZB150), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a light brown oil with N and S levels of 26 ppmw and 9 ppmw, respectively, was obtained.

[0057]

[0077] Adsorption Process 10: Sample 1 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, HBETA (Clariant, HCZB150), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, 5.0 g of a fourth adsorbent, fuller's earth, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, 5.0 g of a fourth adsorbent, fuller's earth, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the solvent, a colorless oil with N and S levels of 17 ppmw and 5 ppmw, respectively, was obtained.

[0058]

[0078] Adsorption Process 11: Sample 2 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, silica gel, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent and removing the solvent, a brown oil with N and S levels of 403 ppmw and 96 ppmw, respectively, was obtained.

[0059]

[0079] Adsorption Process 12: Sample 2 (10.0 g) was dissolved in 30.0 g of toluene, followed by the addition of 5.0 g of bentonite-HCl. The resulting mixture was shaken for 2-24 hours. After filtering to remove the first adsorbent, 5.0 g of a second adsorbent, HZSM-5 (Zeolyst, CBV3024E), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the second adsorbent, 5.0 g of a third adsorbent, silica gel, was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, 5.0 g of a fourth adsorbent, HBETA (Clariant, HCZB150), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the third adsorbent, 5.0 g of a fourth adsorbent, HBETA (Clariant, HCZB150), was added. The resulting mixture was shaken for 2-24 hours. After filtering to remove the solvent, a brown oil with N and S levels of 299 ppmw and 59 ppmw, respectively, was obtained.

[0060]

[0080]

[0061] [Table 1]

[0062]

[0081]

[0063] [Table 2]

[0064]

[0082] The acid / base extraction process and the 70% aqueous methanol extraction process are comparable in terms of extraction of phenols from coal tar, but the acid / base extraction process is significantly superior to the aqueous methanol extraction process in terms of removal efficiency of nitrogen and sulfur-based pollutants.

[0065]

[0083] The adsorbent combinations with the best efficiency for removing nitrogen and sulfur contaminants were bentonite-HCl / HZSM-5 / fuller's earth and bentonite-HCl / HZSM-5 / sepiolite, both of which reduced the levels of nitrogen and sulfur contaminants to less than 10 ppm.

[0066]

[0084] The term "about" means within 10%, or within 5%, or within 1% of a value.

[0085] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment or exemplary embodiments are examples only and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description provides those skilled in the art with a convenient road map for implementing exemplary embodiments of the invention. It will be understood that various changes may be made in the function and arrangement of elements described in the exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.

Claims

1. 1. A method for removing contaminants from crude coal-derived phenols, comprising: removing organic sulfur compounds and organic nitrogen compounds from a crude phenol stream comprising coal-derived crude phenols using an extraction process to form an extracted effluent stream having reduced levels of one or more of the organic sulfur compounds and organic nitrogen compounds compared to the crude phenol stream; removing a portion of one or more of the organic sulfur compounds and organic nitrogen compounds from the extract effluent using an adsorption process comprising a first adsorption zone having a first adsorption agent and a second adsorption zone having a second adsorbent to form an adsorbed effluent having reduced levels of the one or more of the organic sulfur compounds and organic nitrogen compounds compared to the extract effluent, wherein the first adsorbent comprises clay and the second adsorbent comprises zeolite.

2. 10. The method of claim 1, wherein the reduced level of organic sulfur compounds in the extract effluent is less than 100 ppmw, or the reduced level of organic nitrogen compounds in the extract effluent is less than 100 ppmw, or both.

3. 3. The method of claim 1 or 2, wherein the reduced level of organic sulfur compounds in the adsorption effluent is less than 10 ppmw, or the reduced level of organic nitrogen compounds in the adsorption effluent is less than 10 ppmw, or both.

4. The following formula: [Equation 1] The method according to any one of claims 1 to 3, wherein the recovery rate of phenols calculated by the following formula is 90% or more.

5. 5. The method of any one of claims 1 to 4, wherein the extraction process comprises an acid-base liquid extraction process or an aqueous methanol liquid extraction process.

6. The method of any one of claims 1 to 5, wherein the clay comprises one or more of bentonite and HCl-activated bentonite.

7. The method of any one of claims 1 to 6, wherein the zeolite comprises one or more of HZSM-5 zeolite and HBETA zeolite.

8. The method of any one of claims 1 to 7, wherein the adsorption process further comprises a third adsorption zone comprising a third adsorbent.

9. 9. The method of claim 8, wherein the third adsorbent is different from the first adsorbent and the second adsorbent.

10. 9. The method of claim 8, wherein the clay of the first adsorbent comprises one or more of bentonite and HCl-activated bentonite, the zeolite of the second adsorbent comprises one or more of HZSM-5 zeolite and HBETA zeolite, and the third adsorbent comprises one or more of HZSM-5 zeolite, HBETA zeolite, silica gel, sepiolite, and fuller's earth.

11. 11. The method of any one of claims 1 to 10, wherein the adsorption process further comprises a third adsorption zone having a third adsorbent, wherein the first adsorbent comprises HCl-activated bentonite, the second adsorbent comprises HZSM-5 zeolite, and the third adsorbent comprises one or more of fuller's earth or sepiolite.

12. The method of any one of claims 1 to 11, wherein the first adsorbent zone and the second adsorbent zone are in separate vessels.

13. 13. The method of any one of claims 1 to 12, wherein the first adsorbent zone and the second adsorbent zone are in a single vessel, and the first adsorbent zone is disposed above the second adsorbent zone, or the second adsorbent zone is disposed above the first adsorbent zone.

14. 14. The process of any one of claims 1 to 13, wherein the crude phenol stream is passed through the adsorbent bed in upflow or downflow.

15. The process of any one of claims 1 to 14, wherein the adsorption effluent stream is colorless.

16. 16. The process of any one of claims 1 to 15, wherein the crude phenol stream comprises a portion of a coal-derived feed stream, the portion having a boiling point of about 300°C or less.

17. 17. The method of any one of claims 1 to 16, wherein the crude phenol stream comprises a portion of one or more of a low temperature coal tar stream, a medium temperature coal tar stream, a high temperature coal tar stream, a cresylic acid stream, or a crude phenol mixture.

18. 18. The process of any one of claims 1 to 17, wherein at least one of the first adsorption zone and the second adsorption zone comprises at least one of a fixed bed, a fluidized bed, a moving bed, and a rotating bed.

19. 1. A method for removing contaminants from crude coal-derived phenols, comprising: removing organic sulfur compounds and organic nitrogen compounds from a crude phenol stream comprising coal-derived crude phenols using an extraction process to form an extracted effluent stream having reduced levels of one or more of the organic sulfur compounds and organic nitrogen compounds compared to the crude phenol stream, wherein the extraction process comprises one or more of an acid-base liquid extraction process and an aqueous methanol liquid extraction process; removing a portion of one or more of the organic sulfur compounds and organic nitrogen compounds from the extract effluent using an adsorption process comprising a first adsorption zone having a first adsorption agent and a second adsorption zone having a second adsorbent to form an adsorbed effluent having reduced levels of the one or more of the organic sulfur compounds and organic nitrogen compounds compared to the extract effluent, wherein the first adsorbent comprises one or more of bentonite, HCl-activated bentonite, silica gel, sepiolite, and fuller's earth, and the second adsorbent comprises HZSM-5 zeolite and HBETA zeolite.

20. 1. A method for removing contaminants from crude coal-derived phenols, comprising: removing organic sulfur compounds and organic nitrogen compounds from a crude phenol stream comprising coal-derived crude phenols using an extraction process to form an extracted effluent stream having reduced levels of one or more of the organic sulfur compounds and organic nitrogen compounds compared to the crude phenol stream; removing a portion of one or more of the organic sulfur compounds and organic nitrogen compounds from the extract effluent using an adsorption process comprising at least one adsorption zone having an adsorbent to form an adsorbed effluent having reduced levels of the one or more of the organic sulfur compounds and organic nitrogen compounds compared to the extract effluent, wherein the adsorbent comprises one or more of bentonite, HCl-activated bentonite, silica gel, sepiolite, fuller's earth, and a mixture of one or more of HZSM-5 zeolite, HBETA zeolite.

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