JP2010221188A - Method for regenerating adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regenerating an adsorbent, in which a residual sulfur compound, a carbon compound or the like being a substance for deteriorating the desurfurization activity of the adsorbent is removed efficiently to recover the desurfurization activity of the adsorbent and which does not deteriorate the activity of the adsorbent even when the absorbent is regenerated and used repeatedly. <P>SOLUTION: The method for regenerating the zeolite adsorbent for removing the sulfur content of hydrocarbon oil comprises: the first step of heat-treating the zeolite adsorbent, whose desurfurization activity is deteriorated, in a gas stream containing no oxygen substantially at 300-800°C; and the second step of further heat-treating the zeolite adsorbent heat-treated at the first step in an oxygen-containing air stream at 300-800°C. It is preferable that the oxygen content in the gas stream containing no oxygen substantially at the first step is ≤0.01 vol.% or zero, that in the oxygen-containing air stream is 0.1-21 vol.%, and the sulfur content in the adsorbent after the first step is ≤0.05 wt.%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for regenerating an adsorbent containing zeolite used for desulfurization of hydrocarbon oil containing sulfur.

  In the field of petroleum refining, hydrocarbons are used for various fuels, solvents, petrochemical raw materials, and the like, so sulfur content is reduced from the viewpoint of environmental considerations. Various methods are known for desulfurization of hydrocarbon oils, but the carbon and sulfur components deposited on the used catalyst and adsorbent may deteriorate and deactivate due to long-term use. Are known. Various methods have been proposed for regenerating the catalyst and adsorbent whose performance has been reduced or deactivated (Patent Documents 1 and 2).

  For example, in Patent Document 1, a catalyst in which about 5 to 30% by weight of carbon and about 2 to 10% by weight of sulfur are deposited is regenerated at a temperature of 1200 ° F. (648.9 ° C.) or less using an oxygen-containing gas. A method has been proposed. However, looking at the carbon and sulfur removal levels of the regenerated catalyst, even at low levels, the carbon content is about 0.3% by weight and the sulfur content is about 0.5% by weight, which is not always satisfactory. It was difficult to say that the recovery of the activity of the regenerated catalyst was sufficient. In addition, by repeating desulfurization and regeneration, there is a problem that sulfur is gradually accumulated in the adsorbent and the desulfurization activity gradually decreases.

  Patent Document 2 proposes a method in which a desulfurization adsorbent in light hydrocarbon oil obtained from a heavy oil pyrolysis apparatus is regenerated by heat treatment at 300 to 600 ° C., and desulfurization and regeneration are repeated. . As a regeneration method, air is used, and there is a problem that sulfur is gradually accumulated in the adsorbent and the desulfurization activity gradually decreases by repeating desulfurization and regeneration as described above.

JP-T-08-507468 JP 2006-335866 A

  The present invention avoids a decrease in activity due to the accumulation of sulfur content due to repeated use, and thus a method for regenerating an adsorbent that efficiently removes residual sulfur compounds that cause a decrease in desulfurization activity and restores the desulfurization activity. It is an issue to provide.

  As a result of intensive studies, the present inventors have conducted heat treatment under an oxygen-free air stream, and then regenerated the adsorbent under an oxygen-containing air stream, so that the adsorbent can be repeated even if adsorption desulfurization and regeneration are repeated. The present inventors have found that no sulfur accumulation is observed and that the initial desulfurization activity can be maintained, and the present invention has been conceived.

That is, the present invention is as follows.
(1) A method for regenerating a zeolite adsorbent for removing sulfur contained in a hydrocarbon oil, wherein the zeolite adsorbent having a reduced desulfurization activity is heated at 300 to 800 ° C. in an air stream substantially free of oxygen. A method for regenerating a zeolite adsorbent comprising a first step of heat treatment and a second step of heat treatment at 300 to 800 ° C. in an oxygen-containing airflow after the first step.
(2) The oxygen content in the substantially oxygen-free air stream in the first step is 0.01% by volume or less or zero, and the oxygen content in the oxygen-containing air stream in the second step is 0.1% to 21 The method for regenerating a zeolite adsorbent according to the above (1), which is% volume%.
(3) The method for regenerating a zeolite adsorbent according to (1) or (2) above, wherein the sulfur content in the adsorbent after the first step is 0.05% by weight or less.
(4) A hydrocarbon oil desulfurization method for removing sulfur contained in hydrocarbon oil using the zeolite adsorbent regenerated by the adsorbent regeneration method according to any one of (1) to (3) above.

  By the regeneration method according to the present invention, the residual sulfur compound that is the cause of the decrease in the desulfurization activity can be efficiently removed, so that the desulfurization activity of the adsorbent can be recovered. As a result, even if the desulfurization-regeneration cycle is repeated, the initial desulfurization activity does not decrease, so that the adsorbent can be regenerated repeatedly and used over a long period of time.

  The method for regenerating a zeolite adsorbent according to the present invention is a method for regenerating a zeolite adsorbent that removes sulfur contained in a hydrocarbon oil, and adsorbed with desulfurization activity reduced due to accumulation of impurities such as carbon and sulfur. The first step of heat-treating the agent at 300 to 800 ° C. under an air flow with an oxygen content of 0.01% by volume or less, and then the second step of heat-treating at 300 to 800 ° C. under an oxygen-containing air flow. This is a method for regenerating a zeolite adsorbent.

The zeolite adsorbent targeted by the regeneration method of the present invention may be an adsorbent having an adsorption ability for low molecular weight disulfides, mercaptans, sulfides, thiophenes and the like. Examples of such a zeolite adsorbent include X-type zeolite and Y-type zeolite, which are faujasite type zeolites. Adsorbents having a faujasite-type zeolite content of 50% by weight or more, preferably 75% by weight or more, and more preferably 95% by weight or more are suitable. If the zeolite content is less than 50% by weight, the desulfurization performance is lowered, which is not preferable. Examples of components other than zeolite include a binder used for bonding zeolite. As the binder, porous and amorphous ones such as alumina, silica-alumina, titania-alumina, zirconia-alumina, and boria-alumina can be suitably used. Of these, alumina, silica-alumina, and boria-alumina are preferred because they have a strong ability to bind zeolite and have a high specific surface area. These have a role of improving the strength of the catalyst.
The X-type or Y-type zeolite preferably has a Si / Al (molar) ratio of 0.6 to 4.0, more preferably 1.2 to 3.0. Further, the cation contained in the zeolite is preferably sodium or proton.

  Desulfurization of the hydrocarbon oil can be performed by a known adsorption operation. For example, it is usually performed by a continuous processing method such as adsorption by a fixed bed, adsorption by a moving bed or fluidized bed, adsorption by a simulated moving bed, etc., but by a batch method such as adding an adsorbent into hydrocarbon oil and stirring. It can also be done. Adsorption conditions such as the amount of hydrocarbon oil, the amount of adsorbent, the oil feed rate of hydrocarbon oil, the contact time with the adsorbent, and the temperature can be set as appropriate. Usually, the adsorption temperature is 60 ° C. or less, and in particular, since the adsorption capacity of the adsorbent can be increased, it is preferable to perform the treatment at a lower temperature. For economic reasons, excessively low temperatures should be avoided, and near room temperature is more preferred. Further, the adsorbent and the hydrocarbon oil are preferably contacted in a liquid layer, but may be contacted in a gas phase state.

  Further, the zeolite adsorbent is effective for desulfurization of hydrocarbon oil containing disulfide. Therefore, carbonization containing disulfides as an organic sulfur compound is preferably 10% or more, more preferably 50% or more, and particularly preferably 80% or more. Suitable for treatment of hydrogen oil. Furthermore, the olefin content of the hydrocarbon oil is preferably 80% or less, more preferably less than 50%, which is also effective for treatment. As hydrocarbon oil containing an olefin, pyrolysis oil and catalytic cracking oil are preferable.

  On the used zeolite adsorbent, carbon, sulfur and the like are deposited, and the desulfurization performance is lowered. The adsorbent that is the target of the regeneration method of the present invention is an adsorbent with reduced desulfurization performance (hereinafter referred to as spent adsorbent), and has a carbon content of 0.1 wt% or more, preferably 1 to 15 wt%. %, More preferably 6 to 9% by weight, and a sulfur content of 0.1% by weight or more, preferably 0.5 to 5.0% by weight, more preferably 1.0 to 3.0% by weight It is.

In the first step of the regeneration method of the present invention, the spent adsorbent in which the carbon content, sulfur content, etc. are deposited and the desulfurization performance is lowered is heat-treated at 300 to 800 ° C. in an air stream substantially free of oxygen. The oxygen content in the air stream containing substantially no oxygen is preferably 0.01% by volume or less, more preferably 0.005% by volume or less, and particularly preferably 1% by volume or less in the air stream. As a component other than oxygen, an inert gas such as nitrogen, helium or argon is preferably 99.99% by volume or more, and nitrogen can be preferably used. When the oxygen content is 0.01% by volume or less, most of the sulfur content deposited on the adsorbent can be removed by the heat treatment in the absence of oxygen, and the sulfur content deposited in the subsequent second step is removed. This is for thorough removal.
In addition, since zeolite has a crystal structure that is easily destroyed by moisture, it is desirable that zeolite does not contain moisture.

  The treatment temperature in the first step is 300 to 800 ° C. Outside this range, the sulfur content is not sufficiently removed, which is not preferable. Further, the treatment temperature depends on the kind of the adsorbent. In the case of X-type zeolite, 300 to 600 ° C is preferable, more preferably 400 to 500 ° C, and in the case of Y-type zeolite, 500 to 800 ° C is preferable. Preferably it is 600-700 degreeC. Since the temperature of the adsorbent does not cause an exothermic reaction such as combustion, it can be controlled by adjusting the temperature of the airflow to a predetermined temperature.

The first step and the second step described later may be performed on-site while the adsorbent is contained in the adsorbent tank (desulfurizer), or the adsorbent is taken out from the adsorbent tank (desulfurizer) and off-site. You can do either. When the heat treatment of the first step is performed on-site, the gas space velocity (GHSV) is preferably 100 to 2000 h ⁻¹ , more preferably 600 to 1200 h ⁻¹ . When performed off-site, a tubular furnace or muffle furnace is used, and the gas flow rate is heated at 0.5 to 10 L / min, more preferably 3 to 6 L / min while continuously moving the spent adsorbent with reduced desulfurization activity. It is preferable to process. Even in the case of off-site, an inert gas having an oxygen content of 0.1% by volume or less may be heat-treated through the adsorbent layer while being filled in the container as in the case of on-site. Further, it is usually carried out under normal pressure, but it can be carried out under pressure or under reduced pressure.

There is no restriction | limiting in particular in heat processing time. As the heat treatment temperature is lower and shorter, the thermal history can be suppressed and the repeated cycle life can be extended, which is more economical.
In the first step, it is preferable to remove 80% or more of the sulfur content on the spent adsorbent, and the sulfur content of the adsorbent is preferably 0.05% by weight or less. If the removal of the sulfur content in the first step is insufficient, the sulfur content remains even after the heat treatment in the second step, and the desulfurization performance of the regenerated adsorbent is not sufficiently recovered.

  In the regeneration method of the present invention, in addition to the heat treatment of the first step, it is preferable to perform a second step of heat treatment at 300 to 800 ° C. in an oxygen-containing air stream. In this second step, the carbon component burns in contact with oxygen. For this reason, it is preferable to gradually introduce oxygen (or air) after the first step to gradually increase the oxygen concentration of the oxygen-containing gas in order to avoid an excessive temperature rise due to combustion of carbon. Although the final oxygen concentration in the second step may be high, it is 30% by volume or less, preferably 0.1 to 21% by volume from the economical aspect. Up to 21% by volume is more economical because air can be used.

  As a component other than oxygen, an inert gas such as nitrogen, helium, or argon is preferable. For the above reasons, it is desirable not to contain moisture. In particular, when air is used as the oxygen-containing gas, it is preferable to use dry air or dehydrated air.

The treatment temperature in the second step is 300 to 800 ° C. Outside this range, the carbon content is not sufficiently removed, which is not preferable. Further, the treatment temperature depends on the kind of the adsorbent. In the case of X-type zeolite, 300 to 600 ° C is preferable, more preferably 400 to 500 ° C, and in the case of Y-type zeolite, 500 to 800 ° C is preferable. Preferably it is 600-700 degreeC. In particular, when regenerating by passing an oxygen-containing air stream through the adsorbent layer (bed), the carbon content burns and the temperature of the adsorbent rises while the oxygen concentration is increasing. In such a case, the temperature of the adsorbent is controlled by appropriately adjusting the temperature of the airflow, the flow rate of the airflow, the oxygen concentration, and the like. If the temperature of the adsorbent does not become higher than the air flow temperature to be introduced even if the oxygen concentration is increased, it means that the combustible (carbon, sulfur) has been removed. Whether or not the carbon content and further the sulfur content have been completely removed is preferably absorbed even if heat treatment is performed for 1 to 2 hours while maintaining an oxygen concentration of 10% by volume or more, more preferably 20% by volume or more. This can be determined by confirming that the temperature of the agent does not increase, or that CO ₂ and SO ₂ are not recognized in the exhaust airflow.

  The regenerated adsorbent after completion of the second step has a carbon content of 0.2% by weight or less, preferably 0.1% by weight or less, more preferably 0.05% by weight, and a sulfur content of 0.2% by weight. % Or less, preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and particularly 0.02% by weight or less, to recover the desulfurization performance.

  The adsorbent regenerated in this way can be used again for hydrocarbon oil desulfurization, and exhibits desulfurization activity comparable to that of a fresh adsorbent. If desulfurization is continued, impurities such as carbon and sulfur are deposited and the desulfurization activity is lowered. Therefore, the regeneration of the present invention in the first step and the second step is performed. By repeating this series of operations, the desulfurization activity equivalent to that of a fresh adsorbent could be recovered even when the adsorbent was regenerated five times as shown in the examples.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

As the hydrocarbon oil, a model oil imitating a light hydrocarbon oil containing disulfides derived from a heavy oil pyrolysis apparatus was prepared as follows.
As hydrocarbon components, n-decane (special grade manufactured by Wako Pure Chemical Industries, 99% purity) is 54% by weight, 1-hexene (reagent grade 1 manufactured by Tokyo Chemical Industry, purity 95%) is 45% by weight, 1, 3 1% by weight of pentadiene (reagent manufactured by Tokyo Chemical Industry Co., Ltd., cis− + trans− = about 40%) was mixed. Next, dimethyl disulfide (DMDS) (Wako Pure Chemical Industries grade 1 grade, purity 99%) was added to this mixed oil as a sulfur content of 1000 ppm by weight, n-butyl mercaptan (n-BuSH) (Tokyo Chemical Industry grade 1 grade). ) With a sulfur content of 100 ppm by weight, dimethyl sulfide (DMS) (Pure Chemicals reagent grade, purity 98%) with a sulfur content of 10 ppm by weight, propionitrile (CH ₃ CH ₂ CN) (Tokyo Chemical Industry reagent grade) ) Was mixed to a nitrogen content of 5 ppm by weight to prepare a model oil.

Preparation of spent adsorbent Sodium-type NaX (F-9 sphere manufactured by Tosoh Corporation) and NaY (TSO-320NAA powder manufactured by Tosoh Corporation), which are faujasite type zeolites,
In addition, proton type husy (manufactured by Tosoh Corporation, HSZ-330HUD1C column) and

Four kinds of adsorbents of HY (Tosoh Corporation, HSZ-330HSA powder) 10
0 g was immersed in 600 g of model oil at 25 ° C. for 3 days to desulfurize the model oil. Thereafter, each adsorbent was separated from the model oil by filtration. The separated adsorbent was dried at 30 ° C. for 24 hours to prepare four types of spent adsorbents of NaX, HUSY, HY and NaY.
The carbon content and sulfur content of each fresh adsorbent and spent adsorbent were quantified, and the results are shown in Table 1. Table 1 also shows the measurement results of the sulfur content in the model oil obtained by immersion desulfurization as described above using each fresh adsorbent and collected by filtration.

  In order to evaluate the regeneration method of the present invention, tests of Examples and Comparative Examples were performed as follows using the four types of spent adsorbents obtained as described above.

(Comparative Example 1)
Only the first step was regenerated. That is, 7 g of NaX spent adsorbent was placed on a magnetic boat, and in a nitrogen stream at 4 L / min using a ring furnace (nitrogen purity: 99.99 vol%, oxygen content: 0.005 vol% or less, moisture 0. 005 vol% or less), the temperature was increased from room temperature to 400 ° C. at a rate of 5 ° C./min, and then heat treatment was performed at 400 ° C. for 3 hours. The carbon content and sulfur content of the adsorbent after the first step were quantified, and the results are shown in Table 2. In addition, using the regenerated adsorbent only in the first step, the desulfurization performance evaluation test by the same immersion as in the case of the fresh adsorbent was performed. That is, 1.0 g of the regenerated adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the desulfurized model oil was measured. The results are also shown in Table 2.

Example 1
In the same manner as in Comparative Example 1, the spent adsorbent was heat-treated in the first step, and subsequently, in the second step, dry air (oxygen concentration 21 vol%, moisture 0.2 vol% or less) in a nitrogen stream. The oxygen concentration was gradually increased and the oxygen concentration was adjusted to 21% over 1 hour. After the oxygen concentration reached 21%, heat treatment was performed at 400 ° C. for 2 hours.
The carbon content and sulfur content of the adsorbent obtained after regeneration (heat treatment in the first step and the second step) were quantified in the same manner as in Example 1, and 1.0 g of the adsorbent after regeneration was regenerated as 10.0 g of model oil. It was immersed for 3 days at 25 ° C. for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Example 2)
The adsorbent deteriorated by immersing 3 g of the adsorbent regenerated in Example 1 in 30 g of model oil at 25 ° C. for 3 days is subjected to the second regeneration by performing the same first and second steps as in Example 1. It was. Furthermore, this immersion deterioration and regeneration were repeated, and the regeneration was performed 5 times including the regeneration of Example 2. The carbon content and sulfur content of the adsorbent obtained after 5 regenerations were quantified. Further, 1.0 g of the adsorbent after 5 regenerations was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 2)
7 g of NaX spent adsorbent was heated from room temperature to 400 ° C. at a rate of 5 ° C./min in a dry air stream (oxygen concentration 21 vol%, moisture 0.2 vol% or less) at 4 L / min. For 3 hours. After cooling, the carbon and sulfur contents of the adsorbent were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 3)
A desulfurization test was conducted by immersing 3 g of the adsorbent regenerated in Comparative Example 2 in 30 g of model oil at 25 ° C. for 3 days. In the same manner as in Comparative Example 2, the adsorbent was separated and heat-treated in a second oxygen-containing air stream. Furthermore, this heat treatment and desulfurization test by immersion were repeated, and the carbon content and sulfur content of the adsorbent after the fifth heat treatment were quantified. Further, 1.0 g of the adsorbent after the fifth heat treatment was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 4)
The NaX spent adsorbent 3g was subjected to a heat treatment with dry air (oxygen-containing air flow) first, followed by heat treatment with a nitrogen air flow, with the process order of Example 1 changed. The carbon content and sulfur content of the adsorbent after the heat treatment in the reverse process of Example 1 were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

Example 3
The HUSY spent adsorbent was regenerated in the same manner as in Example 1 except that the temperature was raised from room temperature to 600 ° C. at a rate of 5 ° C./min, and both the first and second steps were maintained at 600 ° C. It was. The carbon content and sulfur content of the adsorbent after regeneration were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 5)
The heat treatment was performed on the HUSY spent adsorbent in the same manner as in Comparative Example 2 except that the heat treatment temperature was 600 ° C. The nitrogen content and sulfur content of the adsorbent after heat treatment were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

Example 4
The HY spent adsorbent was regenerated in the same manner as in Example 3. The carbon content and sulfur content of the adsorbent after regeneration were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 6)
The same heat treatment as in Comparative Example 5 was performed on the HY spent adsorbent. The nitrogen content and sulfur content of the adsorbent after heating were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Example 5)
The NaY spent adsorbent was regenerated in the same manner as in Example 3. The carbon content and sulfur content of the adsorbent after regeneration were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

(Comparative Example 7)
The NaY spent adsorbent was subjected to the same heat treatment as in Comparative Example 5. The nitrogen content and sulfur content of the adsorbent after heat treatment were quantified. Further, 1.0 g of this adsorbent was immersed in 10.0 g of model oil at 25 ° C. for 3 days for desulfurization, and the sulfur content of the model oil after desulfurization was measured. These results are shown in Table 2.

In the above evaluation test, the nitrogen content and sulfur content contained in the adsorbent and the sulfur content contained in the model oil were measured as follows.
(1) Carbon content in the adsorbent 1% or more is measured by a ring furnace combustion infrared absorption method, and 1% or less is measured by a high frequency combustion infrared absorption method.
(2) Sulfur content in the adsorbent 1% or more is measured by a ring furnace combustion infrared absorption method, and 1% or less is measured by a high frequency combustion infrared absorption method.
(3) Sulfur content in model oil Measured by ultraviolet fluorescence method.
The recovery rate is a desulfurization recovery rate converted to a value where the desulfurization rate of the fresh adsorbent is 100%.

  From the results in Table 2, in the heat treatment of the spent adsorbent only in the air stream containing no oxygen in the first step, the recovery rate of the desulfurization activity was significantly reduced to 75% by coking. Moreover, in the overheating regeneration process only under the oxygen-containing airflow of the prior art, the activity recovery rate stopped at 98%, and decreased to 92% after repeating 5 times. On the other hand, after the heat treatment is performed in an air stream that does not contain oxygen, the adsorbent is regenerated in an oxygen-containing air stream, so that the residual sulfur compound that is a cause of a decrease in desulfurization activity can be efficiently removed. The activity recovery rate was 100%, the same as the fresh product. Similarly, the activity recovery rate was 100% even after repeating 5 times.

According to the present invention, it is possible to avoid a decrease in desulfurization activity even if the desulfurization agent is repeatedly heated and regenerated. In industrial use, it is sufficient if the running cost is suppressed after recommending the reduction of the adsorbent cost and the regeneration cost, and an economic merit can be obtained at the application location.

Claims (4)

A method for regenerating a zeolite adsorbent that removes sulfur contained in hydrocarbon oil,
A first step of heat-treating the zeolite adsorbent having a reduced desulfurization activity at 300 to 800 ° C. under an air flow containing substantially no oxygen, and 300 to 800 ° C. under an oxygen-containing air flow after the first step. The regeneration method of the zeolite adsorbent including the 2nd process heat-processed with.   The oxygen content in the air stream substantially free of oxygen in the first step is 0.01% by volume or less or zero, and the oxygen content in the oxygen-containing air stream in the second step is 0.1% to 21% by volume. The method for regenerating a zeolite adsorbent according to claim 1.   The method for regenerating a zeolite adsorbent according to claim 1 or 2, wherein a sulfur content in the adsorbent after the first step is 0.05% by weight or less.   A desulfurization method for hydrocarbon oil, which uses the zeolite adsorbent regenerated by the adsorbent regeneration method according to claim 1 to remove sulfur contained in the hydrocarbon oil.