Mineral oils: processes and products – Chemical conversion of hydrocarbons – Cracking
Reexamination Certificate
2001-11-02
2003-12-09
Griffin, Walter D. (Department: 1764)
Mineral oils: processes and products
Chemical conversion of hydrocarbons
Cracking
C208S111050, C208S111300, C208S111350, C208S112000
Reexamination Certificate
active
06660157
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a new heavy oil hydrocracking process using a multimetallic liquid catalyst in a slurry-bed, particularly an improvement of lightweight treatment of heavy oil in the petroleum processing technology. According to the present invention, a slurry-bed hydrocracking reactor and the highly dispersed multimetallic liquid catalyst are mainly applied during the process. A fixed-bed hydrotreating reactor is also used on line to enhance lightweight oil yield from heavy oil under normal pressure.
BACKGROUND OF THE INVENTION
In today's world, research on slurry-bed hydrocracking processes are very active. There are now more than ten such technologies that are in pilot test stage. Some of them have already had industrialized application. But, in these technologies, there exist numerous limitations and shortcomings. The following are some examples.
One example is the VEBA-Combi-Cracking (VCC) process developed in Germany. This process adopts red mud, i.e., a kind of solid material with iron content, and the fine coke powder of Bovey coal as a catalyst. In this technology, not only is the reaction pressure (30-75 Mpa) relatively high, but also a relatively large amount of catalyst, such as about 5% weight percent of raw materials, must be used.
A second example is the Micro-Cat technology developed by ExxonMobil. In this technology, phospho-molybdic acid and molybdenum naphthenate are used as catalyst. Although the dispersion rate and activity of the catalyst are high, this technology remains for now in an experimental scale (1 drum/day). A reason may be that the cost of catalyst is relatively high with low economic profit.
A third example is the HDH technology developed by the Venezuelan INTEVEP Company. This technology uses as a catalyst a kind of inexpensive natural ore that is a special local product currently in Venezuela after it is crushed and fined. Although the catalyst is inexpensive, it must be used in a very large amount (2-3 m %). The required separation system for solid matter of catalyst and non-converted bottom oil is relatively complex. Furthermore, the mineral ore is produced specially only in Venezuela.
Still another example is the Canadian CANMET process. The catalyst used in this process is FeSO
4
·H
2
O with a relatively high dosage (1-5%). The desulfuration and denitrogenation rate of this process is not high, although it does appear to achieve the expected quality of products. There also exist some problems in the separation of catalyst and non-converted bottom oil.
A fifth example is the SOC technology developed by a Japanese company, Ashi Kasei Industrial Co. In this technology, the catalyst, consisting of highly dispersed superfine powder and transition metallic compound, is used with high reaction activity and good anticoking effects. But, this process requires a high reaction pressure (20-22 Mpa) and a relatively high investment cost in the facility.
There are other technologies currently available around the world, such as the Aurabon technology developed by the American UOP Company, the HC3 technology developed by Canada, etc. But, some of these technologies are only being tested on an experimental scale, some use too great a dosage of catalyst, some adopt a solid catalyst, and some use expensive catalysts or require high reaction pressures. In these prior processes, the catalyst used is a single catalyst or a mixture of catalysts. Most of the raw materials being processed using the above-discussed technologies were high sulfur-containing heavy oil. The applications of these prior technologies were also limited in processing low sulfur-containing heavy oil.
SUMMARY OF THE INVENTION
In order to avoid the shortcomings of the prior processes, the object of the present invention is to provide a new and improved heavy oil hydrocracking process using a multimetallic liquid catalyst in the slurry-bed.
In order to carry out the aims of this invention, the technical embodiment of this invention can be realized through the following methods:
According to the present invention, a heavy oil hydrocracking process using a multimetallic liquid catalyst in a slurry-bed reactor under normal (atmospheric) pressure is provided. A slurry-bed hydrocracking reactor charged with a multimetallic liquid catalyst and an online fixed-bed hydrotreating reactor are installed. An online mixer is used to make full mixture of feed oil with catalyst, followed by low-temperature sulfidation. The effluent out of the reactors is separated under a high-pressure or low-pressure separating system or using a conventional separating system. Vacuum gas oil is separated and recycled.
Particularly, the present invention provides a heavy oil hydrocracking process using multimetallic liquid catalyst in the slurry-bed reactor under normal pressure conditions. The feeds, namely heavy oil mixed with catalyst and hydrogen, come into the bottom of a slurry bed hydrocracking reactor. The effluent out of the top of the reactor enters a high-temperature and high-pressure separation system whereby the effluent is separated into vapor flow and liquid flow. Vapor flow enters an online fixed-bed hydrotreating reactor, while liquid flow enters a low-pressure separation system. The vapor flow out of the top of the low-pressure separation system is also directed into the online fixed bed hydrotreating reactor after being cooled. The effluent out of the fixed bed hydrotreating reactor is fed into a conventional separation system, such as vacuum distillation tower.
The high-pressure separation system of the present invention preferably includes a hot high-pressure separator and a cold high-pressure separator. The low-pressure separation system used in the present invention preferably includes a flash drum, a vacuum distillation tower, a low-pressure separator, and a cold low-pressure separator
The vacuum gas oil fractionated out of the vacuum distillation tower is returned, at least partially, to a slurry-bed hydrocracking reactor for further treatment.
The fixed-bed hydrotreating reactor is on line in the process of this invention. The hydrogen source comes from hot material flow of the slurry-bed hydrocracking reactor. The online mixer for mixing raw materials and catalyst is preferably a shear pump or a static mixer. In a particularly preferred embodiment, the shear pump is a shear pump with 2-7 levels.
A first portion of the vacuum gas oil fractionated out of the vacuum distillation tower in the low-pressure separation system is returned to the slurry-bed hydrocracking reactor. The other portion is returned to the slurry-bed hydrocracking reactor together with the slurry to enhance the yield of diesel oil.
According to the present invention, the hydrocracking reactor is a total feedback mixed reactor, and the slurry in the reactor is cycled continuously from a circulating pump to maintain a total feedback mixed state. The slurry typically comprises untreated residual oil, liquid catalyst, recycled bottoms, recycled vacuum gas oil and fresh hydrogen.
In carrying out the process of the present invention, the preferred reaction conditions of the slurry-bed hydrocracking reactor are about as follows:
reaction pressure: 8-12 Mpa,
reaction temperature: 420-460° C.,
total volume hourly space velocity: 0.8-1.4 h
−1
,
recycling ratio of bottom oil/fresh raw materials: 0.3-0.8,
dosage of catalyst based on metal: 50-2000 ppm,
ratio of hydrogen to fresh raw materials: 600-1000.
The preferred conditions of the online fixed-bed hydrotreating reactor are about as follows:
reaction temperature: 300-400° C.,
reaction pressure : a little less than the pressure of the hydrocracking reactor of suspension bed,
volume hourly space velocity: 1.0-2.0 h
−1
, and,
ratio of hydrogen/oil: 300-1000.
In other words, the process of the present invention includes many technical innovations to provide a completely new and improved slurry-bed hydrocracking technology. The present invention uses a highly dispersed multimetallic liquid catalyst in a slurry-bed hydrocracking reactor, and it
Deng Wenan
Liang Shichang
Liu Chenguang
Liu Dong
Ma An
Andover-IP-Law
Arnold Jr. James
Griffin Walter D.
PetroChina Company Limited
Silverstein David
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