JPH055877B2 - - Google Patents

Description

[Detailed description of the invention]

B. Object of the Invention Industrial Application Field The present invention relates to a method for adsorbing and removing nitrogen compounds and oxygen compounds contained as impurities in light hydrocarbons, and an adsorbent for the same. Light hydrocarbons, especially light fractions with carbon numbers in the range of 4 to 10 obtained by cracking heavy oil, contain nitrogen compounds and oxygen compounds as impurities in an amount of 10 to 1000% by weight.
ppm, but these impurities cause various problems when using light hydrocarbons as gasoline, solvents, raw materials for chemicals, etc. One of the major problems is that these light hydrocarbons act as catalyst poisons for the catalysts that process them, and effective pretreatment techniques are long-awaited. Conventional technology (1) Hydrorefining method Hydrorefining is a common method for refining hydrocarbons, but the cracked light fraction contains 20 to 50% of olefins, which can be effectively used. This is not preferable since these are hydrogenated at the same time during hydrorefining. (2) Adsorption method Because it was thought that basic nitrogen compounds such as pyridine contained in these light hydrocarbons were particularly harmful to catalysts, titanium oxide and/or silica (unexamined Acidic adsorbents such as silica alumina and alumina were proposed. In addition, in order to further increase the affinity with basic nitrogen compounds, adsorbents such as silica, zeolite was. However, the nitrogen compounds contained in light hydrocarbons include basic ones such as amines and pyridines, and basic ones such as nitriles such as benzonitrile and alkylpyrroles, and oxygen compounds. Adsorbents cannot be selected based solely on acids and bases, as they also contain acidic or neutral substances such as phenols, cresols, and ethers. Therefore, in order to adsorb both acidic and basic substances, an amphoteric substance that is neither an acid nor a base is required. Regarding oxygen compounds, silica gel (Japanese Patent Publication No. 55-44049) has been proposed for removing ethers. In addition, in the patent application No. 63-49471, the surface area is 100~
A method has been proposed for simultaneously adsorbing and removing nitrogen compounds and oxygen compounds using silica gel with an average pore size of 800 m ² /g and an average pore diameter of 10 to 150 Å. However, although silica gel has excellent adsorption performance, it has poor regeneration properties. , performance deteriorates significantly with repeated use. Problems to be Solved by the Invention The present invention provides an adsorbent for nitrogen compounds and oxygen compounds, which is excellent in terms of adsorption performance and reproducibility.
The object of the present invention is to provide a method for refining light hydrocarbons using the same. B. Means for Solving the Constituent Problems of the Invention The method for refining light hydrocarbons according to the present invention involves contacting light hydrocarbons with an adsorbent made of silica alumina carrying 0.1 to 5.5% by weight of rare earth metals to produce hydrocarbons. It is characterized by adsorbing and removing nitrogen compounds and/or oxygen compounds contained therein. The present invention is applicable to light hydrocarbons containing nitrogen compounds and/or oxygen compounds, especially light hydrocarbons containing 4 to 4 carbon atoms.
It is a hydrocarbon such as paraffin or olefin in the range of 10, and may be a single component or a mixture of two or more types of hydrocarbons. Examples of nitrogen compounds and oxygen compounds to be adsorbed and removed include the various compounds listed above, and in particular nitrogen compounds and oxygen contained in light fractions obtained by cracking petroleum and coal-based heavy oils. Effective in removing compounds. The base of the adsorbent of the present invention is amorphous silica alumina, which must have a pore size sufficient to adsorb the substance to be adsorbed as described above. Content 10-50
% by weight is preferred. In addition, the amount of rare earth metals supported on silica alumina is
The amount is 0.1 to 5.5% by weight, preferably 0.1 to 2.0% by weight. As is clear from Example 1 and FIG. 1 below, when the amount of rare earth metal supported is less than 0.1% by weight, and even when it exceeds 5.5% by weight, no improvement in adsorption performance is observed. That is, the effect of improving adsorption performance and regenerating property is observed only when the amount of rare earth metal supported is in the range of 0.1 to 5.5% by weight. Rare earth metals include cerium, lanthanum, yttrium, etc., but they do not need to be pure metals, and mixed rare earth metals that are easily available on the market may be used. Although the contact between the adsorbent and the hydrocarbon can be carried out batchwise by adding the adsorbent to the hydrocarbon, it is preferable to feed the hydrocarbon into a column filled with the adsorbent and treat it continuously. The shape of the adsorbent used when it is packed in a tower may be spherical, extruded, tablet, etc., but it is desirable to have a size of 1 mm or more, preferably about 1 to 5 mm. Furthermore, a plurality of columns, for example two columns, filled with adsorbent may be provided to perform adsorption and regeneration alternately. Adsorption conditions should be room temperature and pressure selected appropriately.
It is best to set it as a range that is not subject to high pressure regulations. Usually less than 10Kg/ ^cm2 . The regeneration conditions are a temperature of 400 to 600° C. and an arbitrary pressure, but usually the adsorbed material is burned while flowing an oxygen-containing gas at a pressure in the range of normal pressure to 10 kg/cm ² . The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples. [Example 1] Silica alumina (1.8% by weight) containing 28% by weight of Al ₂ O ₃
A predetermined amount of a commercially available mixed rare earth reagent (mainly cerium and lanthanum) dissolved in water (~3 mm extrusion molded product) was impregnated with a predetermined amount, dried, and calcined at 500°C in air.
An adsorbent having the composition shown in the table was obtained. As a hydrocarbon raw material, a heavy oil pyrolysis light fraction (hydrocarbon having 4 to 10 carbon atoms) having the following properties was used. Specific gravity (15/4°C): 0.705 Total N content: 33 weight ppm Total S content: 310 weight ppm Phenol content: 670 weight ppm Olefin content: 31 weight ppm Distillation properties IBP: 33°C EP: 161°C Stainless steel with an inner diameter of 16.1 mm A prepared reactor was filled with 40 ml of the adsorbent shown in Table 1, and after drying at 200° C. for 3 hours in a nitrogen stream, the raw material was passed through at an upflow rate of 80 ml/hr. Adsorption conditions are 5Kg/cm ² G, room temperature,
LHSV2.0hr ^-1 . Analyze the N content of the refined oil at the outlet and find that the N content in the oil is 0.
The amount of oil treated per ml of adsorbent in ppm by weight was determined. The results are shown in Table 1 and Figure 1.

【table】

[Table] Figure 1 shows the loading rate (wt%) of rare earth metals on silica alumina [shown on the horizontal axis] and the amount of oil processed per ml of adsorbent (indicated on the horizontal axis) to reduce the N content in the hydrocarbon oil to 0 ppm by weight. ml) [shown on the vertical axis]. From the results shown in Table 1 and Figure 1, it can be seen that those with 0.1 to 5.5% by weight of rare earth metals (RE) supported have better adsorption performance than those with no support or those with 5.5% or more of rare earth metals (RE) supported. . [Examples 2 to 5 and Comparative Examples 1 to 4] Repeated adsorption/regeneration tests were conducted. An adsorbent saturated with adsorption in the same manner as in Example 1 was heated to 400° C. while flowing N ₂ gas, and then air was introduced to gradually raise the temperature for regeneration. The regeneration conditions were normal pressure, 500°C, and GHSV75hr ^-1 . Thereafter, the adsorbent was cooled, and the adsorption performance was examined again in the same manner as in Example 1. Table 2 shows the measurement results of the adsorption performance for the first time (initial stage), the second time, third time, and tenth time after repeating adsorption and regeneration.

【table】

[Table] It can be seen that adsorbents carrying 0.5 to 2.0% by weight of rare earth metals (RE) are superior in terms of adsorption performance and regeneration performance to those not carrying it or those carrying 8.0% by weight. [Example 6] Adsorbent (RE) was placed in a 1-inch stainless steel reaction tube.
Filled with 800 ml of 28 wt% Al ₂ O ₃ -containing silica alumina carrying 0.5 wt% of
The raw material was processed at LHSV2.0hr ^-1 . Air regeneration was performed when the adsorbent was saturated, and adsorption regeneration was repeated. Table 3 shows the N content and O analysis values for the 1st and 10th tests.

[Table] It can be seen that the adsorption performance of the adsorbent of the present invention for N and O (phenol) does not change even after repeated adsorption and regeneration. [Reference experiment] Relationship between the alumina (Al ₂ O ₃ ) content in silica alumina, which is the base of the adsorbent, and the amount of oil processed (ml) per 1 ml of adsorbent at which the N content in the hydrocarbon oil becomes 0 ppm by weight The results obtained according to Example 1 are shown in FIG. In FIG. 2, the horizontal axis shows the alumina content (% by weight) in silica-alumina, and the vertical axis shows the oil processing amount (ml) per ml of adsorbent at which the N content in the hydrocarbon oil becomes 0 ppm by weight. The lower the alumina content and the higher the silica content, the larger the surface area and the better the adsorption performance.
High silica content does not permit regeneration and is difficult to form for filling the reactor, so the practical range is alumina content of 10 to 50.
Weight%. [Effects of the Invention] Since the adsorbent of the present invention is excellent in adsorption performance and regeneration performance, nitrogen compounds and oxygen compounds can be efficiently removed from light hydrocarbons.

[Brief explanation of drawings]

Figure 1 shows the loading rate (wt%) of rare earth metals on silica alumina [shown on the horizontal axis] and the amount of oil processed per ml of adsorbent (ml) at which the N content in the hydrocarbon oil becomes 0 ppm by weight. Figure 2 shows the relationship between the alumina content (wt%) in silica-alumina, which is the base of the adsorbent [shown on the horizontal axis], and the relationship between the N content in the hydrocarbon oil and the weight of 0% in the hydrocarbon oil. It is a diagram showing the relationship with the oil processing amount (ml) [shown on the vertical axis] per ml of adsorbent in ppm.

Claims (1)

[Claims] 1 Light hydrocarbons are brought into contact with an adsorbent made of silica alumina carrying 0.1 to 5.5% by weight of rare earth metals to adsorb and remove nitrogen compounds and/or oxygen compounds contained in the hydrocarbons. A method for refining light hydrocarbons. 2. The method for refining light hydrocarbons according to claim 1, wherein the light hydrocarbons are light fractions obtained by cracking heavy oil. 3. An adsorbent for refining light hydrocarbons, characterized by being made of silica alumina carrying 0.1 to 5.5% by weight of rare earth metals. 4. The adsorbent for light hydrocarbon purification according to claim 3, wherein the alumina content in the silica alumina is 10 to 50% by weight.