Process for hydroconverting a heavy hydrocarbon chargestock

Details Process for hydroconverting a heavy hydrocarbon chargestock Process for hydroconverting a heavy hydrocarbon chargestock

2002-01-04

2004-04-27

Griffin, Walter D. (Department: 1764)

Mineral oils: processes and products

Chemical conversion of hydrocarbons

Cracking

C208S04800Q, C208S002000, C208S018000, C208S107000, C208S112000, C208S21600R

Reexamination Certificate

active

06726833

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a process for hydroconverting a heavy hydrocarbon chargestock, in particular, to a novel process for hydrocracking heavy hydrocarbons.
BACKGROUND OF INVENTION
The lightening of heavy oil has become a major task of the refining workers along with the heavier and heavier crude oil and the increasing demand for light oil. Hydroconversion of heavy oil is one of the major processes for the lightening of heavy oils. It not only can largely remove the adverse impurities such as metals, sulfur, nitrogen, etc, but also can crack heavy oil and residue into high value components with low boiling point. Presently, industrialized or industrially mature processes for hydroconversion of heavy and residue comprise four categories: fixed bed, moving bed, fluidized bed and suspension bed, wherein the fixed bed process is more popular and most mature. But this process generally requires operation under higher pressure and lower space velocity, and the catalyst is liable to deactivate when processing poor quality oil, and the catalyst bed is readily to be plugged and the operation cycle is short. Therefore, the fixed bed process is generally used for processing chargestocks containing less carbon residue and metals. Although the moving bed and fluidized bed processes can treat poor quality heavy oil, the investment is higher. The suspension bed process for hydrotreating residue is mainly used in the lightening of poor quality heavy oils. This process has not only a lower operation pressure and a higher space velocity, but also a relatively low investment. Therefore, various large petroleum companies are active in the research and development of the suspension bed hydrogenation process.
All suspension bed hydrogenation processes adopt a fine powder or a liquid homogeneous catalyst (or additive), which is mixed with a chargestock oil and then enters into the reactor together with hydrogen in a mode of upward flow to conduct the hydrocracking reaction. The difference is that the catalysts used therein are different. Most of the early suspension bed hydrogenation technologies use solid powder catalysts. For instance, the VCC process developed by Veba Chemie AG of Germany uses pulverized brown coal or coke as the additive. The related patents U.S. Pat. No. 4,299,685, CA 1276902, U.S. Pat. No. 4,999,328, CN 1035836, and CN 1042174 applied for the CANMET process involve an anti-coking agent, flue dust, coal powder supporting metal salts of Fe, Co, Mo, Zn, etc, coke powder and ferric sulfate, iron-coal paste and ultra-fine ferric sulfate, as used in suspension bed process. The HDH process studied and developed by INTEVEP SA of Venezuela uses the fine powder of natural minerals of Ni and V as the catalyst; the Aurabon process of UOP Inc. uses fine powder of vanadium sulfide as the catalyst, and Chiyoda Inc. applies the industrial waste HDS catalyst powder to the medium-pressure suspension bed hydrogenation of residues. It is well known that the function of the solid powder catalyst (or additive) in the suspension bed process for hydrotreating residues is not to promote the cracking reaction. Bench-scale experiments (K. Kretschmar et. al, Erd Oel und Kohle, 39, 9, 418) show that the liquid yields are similar no matter whether the additive is added or not, and the addition of the additive does not change the yield of C
1
-C
4
gases, but somewhat affects the hydrocarbon distribution. The major function of the additive is to adsorb and hydrotreat in the hydrogen atmosphere the macromolecular radicals (a precursor of coke) formed in hydrocracking to prevent them from further condensing to coke. Meanwhile, the small amount of coke produced during reaction and the metals removed from the asphaltene and resin would also deposit on the additive. In addition, the solid powder catalyst (or additive) can prevent the medium phase from aggregating to large particles. However, the hydrogenation activity of the solid powder catalyst (or additive) is not high due to its low dispersion. Therefore, the unit for suspension bed hydrogenation can not effectively inhibit the coking reaction when operating at a higher conversion, thereby the period of the stable operation is shorter.
In order to enhance the dispersion and hydrogenation activity of the catalyst, various large petroleum companies have started to carry out extensive research and development of the homogeneous catalyst process for hydrotreating residues in the suspension bed since late 1980s. Homogeneous catalysts exist in the form of fine particles of metals or their sulfides during reaction and have high dispersion. Although a small amount of the homogeneous catalyst is added in, the hydrogenation activity is high. The homogeneous catalysts already developed include naphthenates or salts of aliphatic acids as disclosed in U.S. Pat. No. 4,226,742 and U.S. Pat. No. 4,134,825 by Exxon Company, carbonyl metal compounds such as carbonyl cobalt, carbonyl nickel, carbonyl molybdenum, and carbonyl iron as disclosed in CA 2004882, molybdenum or tungsten of C
7
-C
12
aliphatic acid as disclosed by Texaco Inc. in U.S. Pat. No. 4,125,455, molybdenum naphthenate combined with cobalt naphthenate as disclosed by IFP in U.S. Pat. No. 4,285,804, water soluble ammonium molybdate catalyst as disclosed in U.S. Pat. No. 4,557,821, U.S. Pat. No. 4,710,486, U.S. Pat. No. 4,762,812, U.S. Pat. No. 4,824,821, U.S. Pat. No. 4,857,496, and U.S. Pat. No. 4,970,190 by Chevron Company. However, the homogeneous catalyst has a rather weak adsorption capacity, and can not prevent the medium phase from aggregating to large particles. The coke formed and the metals removed from asphaltene and resins are liable to deposit and can not be effectively carried out of the unit, resulting in the coking in the reactor, and a shorter period for stable operation.
U.S. Pat. No. 4,066,570 discloses a process for hydrotreating heavy hydrocarbons, wherein two different substances are added during reaction. One is an iron component, which is added in the form of solid particles; the other is an oil soluble metal compound, which is first dissolved in heavy hydrocarbons to be converted into the metal particles with catalytic activity, and then added into the chargestock to effect hydrotreatment together with the ion component. But the final amount of coke is still great, attaining 0.28%, even 0.35%, which therefore would not meet the need of the industrial application.
DISCLOSURE OF THE INVENTION
To solve the aforesaid problems existing in the prior art, the object of the present invention is to provide a process for hydroconverting a heavy hydrocarbon chargestock to produce substantively no coke or less coke in the operation of the suspension bed hydrogenation of residues, thereby prolonging the operation lifetime of the unit.
In order to improve the prior suspension bed process for hydrotreating residues, the present invention provides a multi-stage suspension bed process for hydrotreating residues based on the major functions of two different substances. That is, both a solid powder (a catalyst or an additive) and a homogeneous catalyst (oil soluble or water soluble) are used in the suspension bed process for hydrotreating residues, and they enter the bed reactor from different positions of the reactor so as for them to better exert their respective function.
The embodiment of the present invention is as follows: the homogeneous catalyst (oil soluble or water soluble) is mixed with the heavy hydrocarbon chargestock and hydrogen, and the mixture is pre-heated to a required temperature and is introduced in an upward way into a bed reactor where the hydrocracking reaction takes place. In addition, solid powder is introduced at a position ¼-¾ of the total length from the bottom of the reactor to adsorb the macromolecules produced from the residue in the condensation reaction and carry them out of the reactor.
The homogeneous catalyst used in the present invention comprises all the oil soluble catalysts and the water soluble catalysts suitable for the s

Affiliated with

Also associated with

Rating

Process for hydroconverting a heavy hydrocarbon chargestock does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for hydroconverting a heavy hydrocarbon chargestock, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for hydroconverting a heavy hydrocarbon chargestock will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3271508