CN108435193B

CN108435193B - Reproducible organochlorine removal catalyst and preparation method thereof

Info

Publication number: CN108435193B
Application number: CN201810325562.1A
Authority: CN
Inventors: 夏大寒; 张先茂; 王泽�; 吴阳春; 陈宗杰; 王栋斌; 周正; 瞿玖; 王瑜; 王国兴
Original assignee: Wuhan Kelin Chemical Industry Group Co ltd
Current assignee: Wuhan Kelin Chemical Industry Group Co ltd
Priority date: 2018-04-12
Filing date: 2018-04-12
Publication date: 2020-08-28
Anticipated expiration: 2038-04-12
Also published as: CN108435193A

Abstract

The invention discloses a reproducible organochlorine removal catalyst and a preparation method thereof. The catalyst takes a composite oxide synthesized by an aluminum source, a silicon source and a magnesium source as a carrier and takes Ni, Mo, Cu and Ce as active components. According to the mass percentage of the catalyst, the NiO content in the active component is 6.2-15.6%, the CuO content is 16.1-25.4%, and the MoO₃The content of CeO is 1.7-4.6%₂The content is 1.5-2.5%, and the rest is carrier; the catalyst takes the composite oxide as a carrier, can better disperse active metal, and has an ordered pore channel structure, a specific pore diameter and a larger pore volume. Can effectively remove organic chlorine, avoid subsequent devices from being corroded by inorganic chlorine, and improve the quality of oil products. Meanwhile, the catalyst can be continuously regenerated, so that the startup and shutdown time is reduced, and the production cost is reduced.

Description

Reproducible organochlorine removal catalyst and preparation method thereof

Technical Field

The invention relates to a reproducible catalyst for removing organic chloride in chlorine-containing naphtha and a preparation method thereof, belonging to the field of oil product refining.

Background

In the later period of exploitation of oil field, in order to increase the yield of oil field, some organic chloride-containing auxiliary agent is used to increase the oil recovery rate, resulting in higher chloride content in part of crude oil, and the chlorine-containing compound is mainly enriched in naphtha. The chlorides in naphtha are mainly chloroalkanes, such as: chloroform, dichloromethane, trichloroethane, and the like. At present, the desalting process of crude oil can only remove inorganic chloride in the crude oil, but can not remove organic chloride in the crude oil. Naphtha is used as a raw material for producing ethylene and catalytically reforming, organic chloride in naphtha does not corrode equipment, but in the process of pre-hydrogenation, organic chloride chemically reacts under the conditions of high temperature and high pressure and the presence of hydrogen to produce hydrogen chloride, so that equipment at the downstream of a hydrogenation system is corroded. For example: corroding air cooling equipment and water cooling equipment of the pre-hydrogenation system; the hydrogen chloride reacts with ammonia generated by hydrogenation to generate ammonium chloride, and a pipeline is blocked; even entering the inlet of the pre-hydrogenation recycle hydrogen compressor, and seriously influencing the normal operation of the recycle hydrogen compressor. In order to prevent corrosion of equipment caused by the conversion of organic chlorine to hydrogen chloride during crude oil processing, many researchers have developed various types of dechlorinating agents, some of which have been commercially used for many years. However, these dechlorinating agents mainly focus on the removal of inorganic chlorides from distillate oil, and dechlorinating agents for the removal of organic chlorides have been reported only rarely. US5928500 describes a process for removing trace amounts of organic chlorides from hydrocarbon components by using porous silica having a high specific surface area as a carrier and metals or metal oxides of Ni, Co or iron and mixtures thereof as an adsorbent for the active component to convert the organic chlorides to metal chlorides for removal. CN200810049261 describes an adsorbent for removing organic chloride, which uses porous material, such as molecular sieve, alumina, and activated carbon as carrier, and impregnates metal chloride or mixture of metal chloride and metal sulfate. The adsorbent can convert organic chloride into inorganic chloride under the condition of containing water, and then the inorganic chloride is removed by a water washing method, so that a dechlorination refining step is added, the process is complicated, and the problem of further moisture removal after water washing is also involved. Although the impregnation method is simple and easy to prepare, the surface area and pore volume of the adsorbent are reduced dramatically, so that the dynamic adsorption effect and the bed life are influenced. US3864243 discloses a process for removing chlorides and other impurities from olefin components by adsorption at room temperature and atmospheric pressure using a 13X or 10X zeolite molecular sieve having a pore size of about 8A. US20120190906 discloses the effect of the silicon to aluminum ratio of a molecular sieve on the organochlorine removal capacity, and the results show that a 13X molecular sieve with a silicon to aluminum ratio of less than 1.25 has a higher organochlorine adsorption capacity. Although the 13X molecular sieve has a certain removal effect on organic chlorine, the total adsorption capacity is limited, the dynamic adsorption rate is low, and the service life is short.

Disclosure of Invention

The invention mainly aims at the defects that the catalyst for removing organic chloride in naphtha has low chlorine capacity and can not be regenerated, and the like, and develops a renewable catalyst for removing organic chloride in oil products such as chloric naphtha. The invention provides a reproducible catalyst for removing organic chlorine and a preparation method thereof. The catalyst has good performance of removing organic chlorine and can be regenerated and recycled.

The catalyst of the invention takes a composite oxide synthesized by an aluminum source, a silicon source and a magnesium source as a carrier, and takes Ni, Mo, Cu and Ce as active components to prepare the reproducible organochlorine removal catalyst.

The catalyst is characterized in that: the composite oxide synthesized by the aluminum source, the silicon source and the magnesium source comprises SiO in percentage by mass₂3-10% of MgO, 9.2-18.9% of Al₂O₃。

The content of the active components of the catalyst is calculated by the total mass of the catalyst, the content of NiO in the active components is 6.2-15.6%, the content of CuO is 16.1-25.4%, and MoO₃The content of CeO is 1.7-4.6%₂The content is 1.5-2.5%.

The catalyst is characterized in that: the specific surface area of the catalyst is 430-526 m²The pore volume is 0.85-1.1 ml/g, and the pore diameter is 4-10 nm.

The preparation method of the catalyst is characterized by comprising the following steps: uniformly mixing a certain amount of aluminum source, silicon source, magnesium source, soluble nickel salt, surfactant and water to obtain an initial sol-gel mixture, transferring the initial sol-gel mixture into a synthesis kettle, sealing, and crystallizing at 150-220 ℃ for 8-24 hours. And adjusting the pH value of the crystal slurry to be neutral, adding a certain amount of soluble molybdenum salt, soluble copper salt and soluble cerium salt into the reaction kettle, and carrying out ion exchange reaction for 8-28 h. And after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction. Drying the catalyst for 2 to 4 hours at a temperature of between 100 and 150 ℃, and roasting the dried catalyst for 3 to 6 hours at a temperature of between 500 and 700 ℃ to obtain the reproducible organochlorine removal catalyst.

According to the catalyst provided by the invention, the pore volume, the specific surface area and the pore diameter are measured by a nitrogen low-temperature adsorption method.

The regenerable organic chloride removing catalyst prepared by the method is suitable for treating distillate oil containing organic chloride, can effectively remove the organic chloride and produce the distillate oil containing lower chloride.

Compared with the prior art, the technical scheme of the invention has the following advantages:

(1) from the perspective of molecular structure design, the prepared catalyst has an ordered pore structure, a specific pore diameter and a large pore volume. The performance of the catalyst for adsorbing organic chlorine at low temperature and desorbing the organic chlorine at high temperature is utilized, the defect that the traditional catalyst cannot adsorb the organic chlorine by simply adsorbing and desorbing inorganic chlorine activity is overcome, and the problem that the organic chlorine adsorption catalyst cannot regenerate due to low chlorine capacity is solved.

(2) The magnesium silicate and aluminum silicate adsorbent has good adsorption capacity on organic chloride in naphtha, and the two substances can be regarded as MgO-SiO₂、Al₂O₃ ^.SiO₂I.e. silica loaded with metal oxides. In the mixed adsorbent, the magnesium oxide and the aluminum oxide have synergistic effect, so that the polarity of the adsorbent is increased, and the adsorption capacity of the adsorbent on chlorides in naphtha is improved.

(3) Ce is beneficial to better dispersion of active components such as Ni-Mo-Cu and the like on the surface of the carrier, inhibits the growth of crystal grains, increases the specific surface area and pore volume of the catalyst and increases the chlorine volume. Ce during catalyst calcination³⁺Oxidation valence change to Ce⁴⁺And Ce⁴⁺Has stronger electron obtaining capability, namely the L acid amount is increased, the total acid amount of the Ce modified catalyst is increased, the olefin polymerization of oil products can be effectively inhibited, the coking of the catalyst is prevented, the anti-coking capability of the catalyst is improved, and the catalytic activity is prolongedDechlorination lifetime of the agent.

(4) The environment-friendly nickel-ammonia solution is used as a template agent, and the active component nickel is successfully embedded into the precursor of the microporous catalyst, so that the subsequent synthesis of the active component catalyst, namely Ni-Mo-Cu-Ce, is guaranteed. Because the nickel is embedded into the micropores, nickel atoms can be well protected when the temperature is increased, and meanwhile, the nickel activates active chlorine adsorbed on the catalyst and is desorbed from the catalyst through atom transfer; and the nickel on the catalyst is prevented from being poisoned and can be regenerated and recycled.

The specific implementation example is as follows:

the characteristics of the catalyst, the preparation method and the catalytic performance of the catalyst of the present invention will be described in detail with reference to the following specific embodiments, but the present invention is not limited to these embodiments and does not limit the scope of the invention.

Example 1:

197g of alumina sol (Al)₂O₃Content of (1)%), 33.3g of silica Sol (SiO)₂30 percent of nickel nitrate, 38.1g of tetraethylammonium bromide and 300g of water, stirring for 6 hours, uniformly mixing to obtain an initial sol-gel mixture, transferring the initial sol-gel material into a synthesis kettle, sealing, and crystallizing for 8 hours at 220 ℃. The pH of the crystal slurry was adjusted to neutral with 0.5mol/L urea, and 4.28g of ammonium molybdate, 59.7g of copper nitrate and 6.3g of cerium nitrate were added to conduct an ion exchange reaction for 8 hours. And after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction. Drying at 150 deg.C for 2 hr, and calcining at 500 deg.C for 6 hr to obtain regenerated adsorptive dechlorination catalyst Cat 1.

Example 2:

179g of aluminum sol, 10g of silica sol, 44.6g of magnesium chloride, 15.1g of nickel nitrate, 2.5g of hexadecyl trimethyl ammonium bromide and 300g of water are stirred for 10 hours and mixed uniformly to obtain an initial sol-gel mixture, the initial sol-gel material is moved into a synthesis kettle for sealing and crystallized for 8 hours at 150 ℃. The pH of the crystal slurry was adjusted to neutral with 0.5mol/L urea, and 6.26g of ammonium molybdate, 59.7g of copper nitrate and 6.3g of cerium nitrate were added to conduct an ion exchange reaction for 28 hours. And after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction. Drying at 120 deg.C for 4 hr, and calcining at 500 deg.C for 6 hr to obtain regenerated adsorptive dechlorination catalyst Cat 2.

Example 3

192.5g of aluminum sol, 23g of silica sol, 33g of magnesium chloride, 26.6g of nickel nitrate, 2.5g of tetraethylammonium bromide and 300g of water are stirred for 6 hours and mixed uniformly to obtain an initial sol-gel mixture, the initial sol-gel material is moved into a synthesis kettle for sealing, and crystallization is carried out for 20 hours at 220 ℃. The pH of the crystal slurry was adjusted to neutral with 0.5mol/L urea, and 4.28g of ammonium molybdate, 48.7g of copper nitrate and 5.1g of cerium nitrate were added to conduct an ion exchange reaction for 20 hours. And after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction. Drying at 120 ℃ for 3 hours, and roasting at 600 ℃ for 5 hours to obtain the regenerative adsorption dechlorination catalyst Cat 3.

Example 4:

244g of aluminum sol, 23g of silica sol, 21.7g of magnesium chloride, 26.6g of nickel nitrate, 2.5g of hexadecyl trimethyl ammonium bromide and 300g of water are stirred for 6 hours and uniformly mixed to obtain an initial sol-gel mixture, and the initial sol-gel material is moved into a synthesis kettle to be sealed and crystallized for 20 hours at 180 ℃. The pH of the crystal slurry was adjusted to neutral with 0.5mol/L urea, and 2.3g of ammonium molybdate, 37.8g of copper nitrate and 3.78g of cerium nitrate were added to conduct an ion exchange reaction for 28 hours. And after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction. Drying at 100 ℃ for 4 hours, and roasting at 700 ℃ for 3 hours to obtain the regenerative adsorption dechlorination catalyst Cat 4.

Example 5:

in this example, the activities of the dechlorination catalysts of examples 1 to 4 and the catalyst Cat5 of the prior art were compared and measured.

The above products and the pore properties and acid properties of the coker gasoline desilication catalyst were analyzed, and the analysis results are shown in Table 1

TABLE 1 physicochemical Properties of different catalysts

As can be seen from Table 1, the catalyst Cat 2-4 carrier provided by the invention has better specific surface area and pore volume compared with Cat1 without introducing MgO due to the introduction of MgO. According to the catalyst Cat 1-4 provided by the invention, through a specific preparation process, compared with gamma-Al with the same composition₂O₃Has larger pore diameter and pore volume.

Each of the catalysts prepared in examples was charged in an amount of 30ml into a reaction tube having a diameter of 27X 3.5mm, and the height of the catalyst bed was 48mm, and properties of the raw oil used was naphtha as shown in Table 2.

TABLE 2 naphtha Properties

Item	Density, g/cm³	Total chlorine,. mu.g/g
			Naphtha (a)	0.64	246

Selecting an analyzer: KY-200 microcoulomb chlorine content titrator is used for determining organic chlorine in oil. And (3) loading 30mL of catalyst into a fixed bed reactor, activating in a reactor, introducing hydrogen, adjusting the system pressure to 0.7MPa and the hydrogen amount to 50mL/min, heating to 230 ℃ at the speed of 10 ℃/min, keeping the temperature for 2h, then heating to 400 ℃ at the same heating rate, and keeping the temperature for 4h to completely activate the catalyst. After the activation is finished, the device is replaced by nitrogen, raw oil naphtha is pumped in, and the oil inlet airspeed is 1.5h^-1The reaction temperature is 150 ℃ and the reaction pressure isDechlorination experiment is carried out at 0.7MPa and nitrogen/oil ratio of 100:1, and the dechlorinated product is washed by water to remove inorganic chlorine and then analyzed for organic chlorine content. After the dechlorination effect of the catalyst is reduced, the temperature of the catalyst is increased to 250 ℃ at the speed of 10 ℃/min, the reaction pressure is increased to 1.4 MPa, nitrogen is used for purging, and the regeneration is stopped when the chlorine content is zero through gas detection at the outlet of the reactor. The reaction temperature is reduced to 150 ℃, the pressure is reduced to 0.7MPa, and the dechlorination experiment is carried out again. After a certain time of reaction, a sample was taken for analysis, and the reaction results were recorded as shown in Table 3.

TABLE 3 determination of dechlorination Activity Total chlorine,. mu.g/g

As can be seen from the data in Table 3, the dechlorination catalysts Cat1, Cat2, Cat3 and Cat4 have organochlorine removal experiments in the raw material with the naphtha organochlorine content of about 240 mug/g, the organochlorine removal rate reaches more than 97.9%, while the comparative catalyst Cat5 has a poor organochlorine removal effect in the environment with organochlorine. To further understand the performance of the catalyst of the present invention, the following regeneration experiment was performed on Cat3, and the results are shown in table 3. The experimental results show that: the catalyst Cat3 can effectively adsorb and remove organic chlorine, and can be regenerated and reused. The inventor also adopts the method to carry out long-period experiments on the catalysts obtained in other examples, and can obtain better results, which shows that the catalyst of the invention has better activity and stability.

Claims

1. A reproducible organic chloride removal catalyst is characterized in that: the catalyst takes a composite oxide synthesized by an aluminum source, a silicon source and a magnesium source as a carrier, and takes Ni, Mo, Cu and Ce as active components, and the preparation method of the catalyst comprises the following steps:

uniformly mixing a certain amount of aluminum source, silicon source, magnesium source, soluble nickel salt, surfactant and water to obtain an initial sol-gel mixture, transferring the initial sol-gel mixture into a synthesis kettle, sealing, and crystallizing at 150-220 ℃ for 8-24 hours; adjusting the pH value of the crystal slurry to be neutral, adding a certain amount of soluble molybdenum salt, soluble copper salt and soluble cerium salt into the reaction kettle, and carrying out ion exchange reaction for 8-28 h; after the reaction is finished, adding a flocculating agent into the slurry for precipitation, filtering, washing, drying, extruding and forming, and recycling the filtered liquid for the next reaction; drying the mixture for 2 to 4 hours at a temperature of between 100 and 150 ℃, and roasting the dried mixture for 3 to 6 hours at a temperature of between 500 and 700 ℃ to obtain a reproducible organochlorine removal catalyst;

the surfactant of the preparation method of the catalyst is tetraethylammonium bromide or hexadecyl trimethyl ammonium bromide.

2. The catalyst of claim 1, wherein: the composite oxide carrier is SiO in percentage by weight₂3-10% of MgO, 9.2-18.9% of Al₂O₃。

3. The catalyst of claim 1, wherein: the aluminum source is alumina sol; the silicon source is silica sol; the magnesium source is magnesium chloride.

4. The catalyst of claim 1, wherein: the specific surface area of the catalyst is 430-526 m²The pore volume is 0.85-1.1 ml/g, and the pore diameter is 4-10 nm.

5. The catalyst as set forth in claim 1, wherein: the content of the active components of the catalyst is calculated by the total mass of the catalyst, the content of NiO in the active components is 6.2-15.6%, the content of CuO is 16.1-25.4%, and MoO₃The content of CeO is 1.7-4.6%₂The content is 1.5-2.5%.

6. The catalyst of claim 1, wherein: the preparation method of the catalyst uses urea to adjust the pH value of crystal slurry to be neutral.

7. The catalyst of claim 1, wherein: the soluble molybdenum salt, copper salt and cerium salt of the preparation method of the catalyst are ammonium salt or nitrate.