JP2003119453A - Antifouling agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antifouling agent free from amines, with which fouling is effectively prevented with a small amount of its addition at a low treating cost in hydrocarbon-treating apparatus such as a crude oil pre-heater. SOLUTION: This antifouling agent contains 2,6-di-t-butyl-4-methylphenol and 4-t-butylcatechol.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antifouling agent. More specifically, the present invention is an apparatus for treating hydrocarbons such as a crude oil preheater system, which does not contain amines,
The present invention relates to a stain preventive agent which can efficiently prevent the generation of stains with a small amount added and a treatment cost.

[0002]

2. Description of the Related Art In recent years, continuous operation and high load operation have been performed for many years in order to improve the efficiency of crude oil processing. On the other hand, crude oil tends to be heavier, and salinity, sulfur, suspended matter, and asphaltene are increasing. For this reason, contamination of the crude oil preheater system has become a problem. If the crude oil preheater system becomes dirty, the operation pressure will increase due to an increase in the differential pressure of the heat exchanger and piping, energy loss due to a decrease in the overall heat transfer coefficient of the heat exchanger, and increase in fuel consumption due to a decrease in the furnace inlet temperature. Cause various obstacles such as. Such troubles due to dirt occur not only in the crude oil preheater system but also in various petrochemical processes such as naphtha decomposition and synthetic rubber production. Since the crude oil preheater system and the like cannot be opened during continuous operation, the addition of a stain inhibitor suppresses the generation of stains, and various stain prevention methods have been proposed.
For example, U.S. Pat. No. 3,148,225 proposes a method of adding dialkylhydroxylamines in order to suppress the production of popcorn polymer by the polymerization of olefins in the production process of synthetic rubber. . U.S. Pat. No. 4,456,526 proposes a method of adding dialkylhydroxylamine and t-alkylcatechol to prevent fouling of petroleum processing equipment. Further, US Pat. No. 4,744,881 discloses that a hydrocarbon having a bromine number of 10 or more is treated as a stain prevention method in a petrochemical process containing oxygen, such as phenols and organic amines without steric hindrance. A method of using a strong basic substance in combination has been proposed. Further, JP-A-57-180692 proposes a stain preventive agent containing aniline, paratoluidine or anisidine and 4-t-butylcatechol as a stain preventive agent in the ethylene production process by naphtha decomposition. However, when amines are used as the antifouling agent, the products may be colored or discolored, or the amines may become a catalyst poison when there is a catalytic reaction process in the subsequent step. Also,
If the amount of amines added is large, the cost of chemicals will increase, and there is a risk that economic efficiency will be impaired. Therefore, an effective antifouling agent containing no amines has been demanded.

[0003]

DISCLOSURE OF THE INVENTION The present invention, in an apparatus for treating hydrocarbons such as a crude oil preheater system, does not contain amines and efficiently prevents the generation of dirt with a small addition amount and a treatment cost. The purpose of the present invention is to provide an antifouling agent.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that 2,6-di-t
It was found that by using -butyl-4-methylphenol and 4-t-butylcatechol in combination, both act synergistically and effectively prevent the generation of stains,
The present invention has been completed based on this finding. That is, the present invention provides (1) an antifouling agent containing 2,6-di-t-butyl-4-methylphenol and 4-t-butylcatechol, and (2) 2,6 −
The antifouling agent according to item 1, which contains 0.1 to 10 parts by weight of 4-t-butylcatechol with respect to 100 parts by weight of di-t-butyl-4-methylphenol.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The antifouling agent of the present invention has the formula [1]
2,6-di-t-butyl-4-methylphenol represented by the formula and 4-t-butylcatechol represented by the formula [2] are contained. The antifouling agent of the present invention is a crude oil atmospheric distillation column,
It can be suitably used for a crude oil vacuum distillation column, a hydrodesulfurization process, a fluid catalytic cracking process, an ethylene production process, a synthetic rubber production process and the like. The antifouling agent of the present invention exhibits a remarkable synergistic effect between 2,6-di-t-butyl-4-methylphenol and 4-t-butylcatechol, and the addition of a small amount effectively causes the generation of fouling. Can be prevented.

[Chemical 1] In the antifouling agent of the present invention, the ratio of 2,6-di-t-butyl-4-methylphenol and 4-t-butylcatechol is not particularly limited, but 2,6-di-t-butyl-4.
The amount of 4-t-butylcatechol is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of methylphenol. Two,
If the ratio of 4-t-butylcatechol to 100 parts by weight of 6-di-t-butyl-4-methylphenol is less than 0.1 part by weight, the synergistic effect of both may not be sufficiently exhibited. When the ratio of 4-t-butylcatechol to 100 parts by weight of 2,6-di-t-butyl-4-methylphenol is 10 parts by weight or less, a sufficient synergistic effect is exhibited,
Usually, it is not necessary to include more than 10 parts by weight of 4-t-butylcatechol.

There is no particular limitation on the place where the antifouling agent of the present invention is added. For example, crude oil atmospheric distillation apparatus, vacuum distillation apparatus, hydrorefining apparatus, hydrodesulfurization apparatus, vacuum flushing apparatus, catalytic reforming apparatus, Catalytic cracking equipment, sulfur recovery equipment,
It can be added to dewaxing equipment, asphalt production equipment, paraffin production equipment, ethylene production equipment, diene production equipment, aromatic hydrocarbon extraction equipment, polymerization equipment and the like. The antifouling agent of the present invention can be added as it is, or can be added after being dissolved or diluted in an organic solvent such as benzene, toluene, xylene, or kerosene. The addition amount of the antifouling agent of the present invention is not particularly limited and can be appropriately selected depending on the target device and operating conditions, etc. The amount is preferably 0.01 to 1,000 mg / L, more preferably 0.1 to 500 mg / L, and further preferably 1 to 300 mg / L. The antifouling agent of the present invention, if necessary, a peroxide scavenger,
It can be used in combination with a known antifouling agent such as a radical scavenger, a metal deactivator, and a dispersant. By using the stain inhibitor of the present invention, it is possible to effectively suppress stains generated in various processes with a small addition amount,
The continuous operation time of the plant can be greatly extended.

[0007]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Example 1 100 mL of naphtha was placed in a stainless steel autoclave having a capacity of 200 mL, and 14.65 mg of 2,6-di-t-butyl-4-methylphenol and 0.4-t-butylcatechol.
15 mg was added, and the gas phase part was replaced with oxygen gas and sealed. This autoclave was heated at 150 ° C. for 20 hours and then cooled, naphtha was filtered, and the produced insoluble matter was dried and weighed. The insoluble matter was 97.6 mg. Example 2 2,6-di-t-butyl-4-methylphenol 14.7
The naphtha was heated in the same manner as in Example 1 except that 0 mg and 0.30 mg of 4-t-butylcatechol were added, and the resulting insoluble matter was weighed. The insoluble matter was 66.6 mg. Comparative Example 1 2,6 without the addition of 4-t-butylcatechol
-Di-t-butyl-4-methylphenol only 15.
The naphtha was heated and the resulting insoluble matter was weighed in the same manner as in Example 1 except that 00 mg was added. Insoluble matter is
It was 234.3 mg. Example 3 2,6-di-t-butyl-4-methylphenol 17.3
The naphtha was heated in the same manner as in Example 1 except that 3 mg and 0.17 mg of 4-t-butylcatechol were added, and the resulting insoluble matter was weighed. The insoluble matter was 9.0 mg. Example 4 2,6-di-t-butyl-4-methylphenol 17.1
The naphtha was heated in the same manner as in Example 1 except that 5 mg and 0.35 mg of 4-t-butylcatechol were added, and the resulting insoluble matter was weighed. The insoluble matter was 6.0 mg. Comparative Example 2 2,6 without the addition of 4-t-butylcatechol
-Di-t-butyl-4-methylphenol only 17.
The naphtha was heated in the same manner as in Example 1 except that 50 mg was added, and the resulting insoluble matter was weighed. Insoluble matter is
It was 23.4 mg. The results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1.

[0008]

[Table 1]

As can be seen in Table 1, replacing 1% by weight of 2,6-di-t-butyl-4-methylphenol with 4-t-butylcatechol when the amount of drug added is the same. Yields about 60% by weight of insoluble matter
By replacing 2% by weight of 2,6-di-t-butyl-4-methylphenol with 4-t-butylcatechol, the amount of insolubles produced is reduced by about 70% by weight.

[0010]

The antifouling agent of the present invention is 2,6-di-t.
-Butyl-4-methylphenol is used in combination with a small amount of 4-t-butylcatechol, so that in a device for treating hydrocarbons such as a crude oil preheater system, a small addition amount and a treatment cost can be achieved without using amines. It is possible to efficiently prevent the generation of dirt.

Claims (2)

[Claims] 1. An antifouling agent comprising 2,6-di-t-butyl-4-methylphenol and 4-t-butylcatechol. 2. The antifouling agent according to claim 1, which contains 0.1 to 10 parts by weight of 4-t-butylcatechol based on 100 parts by weight of 2,6-di-t-butyl-4-methylphenol.