FR2512000A1 - Deasphalting of heavy oil coupled with partial oxidn. of asphalt - to synthesis gas, with carbonaceous by=products returned to deasphalting unit - Google Patents

Abstract

A process for prepn. of synthesis gas comprises: (i) solvent deasphalting of a heavy hydrocarbon oil (I) and a recycled mixt. (II) of carbonaceous material (esp. carbon) and the oil (I), using a light hydrocarbon oil (III) as deasphalting solvent; and (ii) partial oxidn. to synthesis gas of the mixt. of C and asphalt so obtd. The mixt. (II) is obtd. by (iii) contacting an aq. suspension of the C byprod. from partial oxidn. with another light hydrocarbon oil (IV); (iv) sepg. the oil phase; (v) adding the heavy oil (I); and (iv) distilling off the light oil (IV) for recycle to step (iii). To obtain synthesis gas from (I), which is a reduced residual oil topped crude, whole crude or liquefied coal. Only the asphalt in (I) (including the (I) used to recover C after oxidn.) is gasified: the deasphalted oil is sepd. for higher-grade use.

Description

 The present invention relates to an improved process for the production of synthesis gas by partial oxidation of a useless heavy hydrocarbon.

 It is known in the art that a synthesis gas containing as main components hydrogen gas and carbon monoxide gas can be produced by partial oxidation of a heavy hydrocarbon oil in the absence of catalyst at elevated temperature. This process is currently used on an industrial scale. Various improvements to this process for the production of synthesis gas by partial oxidation of a heavy hydrocarbon oil have been proposed and concerning for example the replacement of the starting oils, a modification of the composition of the synthesis gas formed (that is to say -display a modification of the ratio of hydrogen gas and carbon monoxide in synthesis gas according to the use for which it is intended) and the treatment and efficient use of carbonaceous materials formed as by-products of synthesis gas .

 For example, an improvement relates to carbonaceous materials (for example carbon) formed as by-products of the partial oxidation of heavy hydrocarbon oil. In general, the carbonaceous materials are mixed with water to form a suspension which is then recovered from a partial oxidation reactor (that is to say a gas generator). Techniques for the production of synthesis gas by partial oxidation of mixtures of carbonaceous materials formed as by-products and of a heavy hydrocarbon oil have been developed (see US Patent 4,016,103).

 Specifically in these techniques, the suspension of carbonaceous materials in water is brought into contact with a light hydrocarbon oil such as naphtha by mutual mixing. The hydrocarbon oil phase obtained containing the carbonaceous materials which have migrated is then separated from the aqueous phase. The separated hydrocarbon oil phase containing the carbonaceous materials is mixed with the starting heavy oil for partial oxidation. then, the 7th mixture obtained is subjected to an operation. distillation (for example rectification) to separate the component consisting of one heavy hydrocarbon tile containing carbonaceous materials and the component consisting of light hydrocarbon oil. The component consisting of the heavy hydrocarbon oil thus obtained is introduced with the starting heavy hydrocarbon oil into a gas generator and is partially oxidized to produce synthesis gas. Thus, the carbonaceous materials formed as by-products in the partial oxidation of heavy hydrocarbon oil is recovered and used effectively as starting materials for the production of synthesis gas. These processes for the production of syngas comprising the efficient recovery and reuse of carbonaceous mayors are very advantageous from the practical point of view.

 The object of the invention is to further improve the processes for the preparation of the abovementioned syngas comprising the recovery and reuse of the carbon by-products of the partial oxidation of the starting oil, such as heavy hydrocarbon oil cited above.

 Other objects and advantages of the invention will emerge from the following description.

The invention relates to a process for the preparation of synthesis gas which comprises the stages of
- solvent deasphalting of a heavy hydrocarbon oil and of a mixture of carbonaceous materials and heavy hydrocarbon oil using light hydrocarbon oil as deasphalting oil; and
- partial oxidation of the mixture obtained from carbonaceous materials and asphalt to produce synthesis gas.

 Said mixture of carbonaceous materials and heavy hydrocarbon oil is obtained by contacting (1) a suspension containing the materials formed as by-products of the partial oxidation of the mixture of carbonaceous materials and asphalt in water with (2) a light hydrocarbon oil, then separate the oily phase and the aqueous phase of the mixture obtained, addition of a heavy hydrocarbon oil to the separate mixture of carbonaceous materials and of hydrocarbon oil l manages and elimination of the oil light hydrocarbon of the mixture obtained.

 The invention will be better understood on reading the following description and with reference to the single figure of the accompanying drawings which is an operating diagram illustrating a process for preparing synthesis gas according to the preferred embodiment of the invention. present invention.

 The term "heavy hydrocarbon oil" used herein means various liquid hydrocarbon oils having a relatively high boiling point, such as reduced residual oil, topped crude oil, whole crude oil (including petroleum derived for example from asphalt sand and oil shale) and liquefied coal.

 The term "light hydrocarbon oil" as used herein means various liquid hydrocarbon oils having a relatively low boiling point and containing mainly paraffinic hydrocarbons, consisting mainly of C7 to C10 hydrocarbons such as naphtha .

 In the practice of the invention, the heavy hydrocarbon oil is not directly subjected to a partial oxidation reaction. The heavy hydrocarbon oil is first subjected to a solvent deasphalting treatment to separate the deasphalted oil and the asphalt. The asphalt thus separated from the heavy hydrocarbon oil is then partially oxidized. The heavy hydrocarbon oil is then led into a solvent deasphalting apparatus 12 by a line 11. A deasphalting solvent (light hydro-carbon oil) is also introduced through a line 13 into the solvent deasphalting apparatus 12. The deasphalting with solvent is carried out in a conventional manner.

 The deasphalted oil and the deasphalting solvent are recovered by a line 14 which can be led into a deasphalted oil separator (HDA separator) 15 after cooling. The deasphalted oil is separated from the solvent for Q-: 3saspnaltage in the rIDA separator 15. The separated flasphalting solvent is discharged through a line 16 for recovering the solvent and, after cooling, the solvent is introduced into a solvent tank 17 to be stored. After the water has been removed, the solvent circulates as de-paving solvent from the solvent tank 17 to the solvent deasphalting device 12 via a pipe 13. If necessary, solvent is supplied. fresh from the outside.

 The deasphalted oil separated in the HDA separator 15 is evacuated by a line 18 for recovering the deasphalted oil and is then conducted in a deasphalted oil rectifier (HDA rectifier) 19. Water vapor is also brought to the AIDS rectifier 19 by a line 20 so that the deasphalting solvent remaining partially in the deasphalted oil is recovered.

The recovered solvent is led into the solvent tank 17 via a line 21 for recovering solvent after cooling. The rectified deasphalted oil is discharged from the HDA rectifier 19 through a line 22.

 The asphalt separated in the solvent deasphalting apparatus 12 is recovered by a pipe 23 and is heated in an asphalt heater 24. The heated asphalt is led to an asphalt separator 25. Thus, the deasphalting solvent remaining in the deasphalted oil is separated in the asphalt separator 25. The separated solvent is recovered by a pipe 26test introduced into the solvent tank 17 after cooling. The separated asphalt is evacuated from the asphalt separator 25 by a line 27 and is led into an asphalt rectifier 28. Water vapor is introduced simultaneously into the asphalt rectifier 28 by a line 29 so that the deasphalting solvent remaining in the asphalt is recovered.

The recovered solvent is led into the solvent tank 17 via a pipe 30 for recovering solvent after cooling. The asphalt separated in the asphalt rectifier 28 is evacuated by a pipe 31 and leads to a gas generator (partial oxidation reactor) 32.

 Oxygen and calf vapor are introduced if ultimately into the gas generator 32 respectively through pipes 93 and 94. The asphalt is thus partially oxidized in the gas generator 32 under conventional conditions such as for example a temperature of 1,200 to 1,500 ° C and a pressure of 20 bars or more to form a synthesis gas containing as main components hydrogen gas, carbon monoxide and water vapor. the synthesis gas obtained and the water vapor are suddenly cooled in the lower part of the gas generator 32 and are evacuated from the gas generator 32 by a pipe 35. The synthesis gas and the water vapor are conducted in a carbon scrubber 36 and the carbon solids contained in the synthesis gas as contaminants are eliminated with sprayed water supplied by a line 37. The purified synthesis gas and the water vapor are evacuated by a line 38. lia suspension containing water and carbonaceous materials separated from the synthesis gas in the carbon washer 36 is discharged through a pipe 39 and conducted in the lower part of the gas generator 32. The suspension is thus used to cool the synthesis gas, and the water vapor and the carbonaceous materials are returned to the lower part of the gas generator 32.

 the suspension containing the carbonaceous materials in the water is discharged from the gas generator 32 e; conducted in a mixer 41 after cooling. A light hydrocarbon-based oil such as a naphtha (for example hydrocarbons pa refined in C5 to C10) is introduced simultaneously by a line 42 from a rectifier 48 of light hydrocarbon oil. The suspension containing the carbonaceous materials in the water and the light hydrocarbon oil are mixed thoroughly and brought into intimate contact in the mixer 41. As a result, the carbonaceous oils of the aqueous phase are transferred to the light hydrocarbon oil .

 v mixture of carbonaceous materials, light hydrocarbon oil and water is discharged to the mixer 41 through a line 3 and is introduced into a decanter 44 where the phase (the light hydrocarbon oil containing the carbonaceous materials and the aqueous phase The water separated under strong from a lower layer in the decanter 44 is evacuated by 12 line 37 and introduced with the feed water coming from a line t5 into the carbon washer 36. is therefore used as purification water to remove the solid carbonaceous materials from the synthesis gas. mixes me carbonaceous materials and light hydro-carbon dioxide separated in the form of an upper layer in the decanter 44, is evacuated by a pipe 46 then is led into the rectifier 48 of light hydrocarbon oil after having been mixed with the heavy hydrocarbon oil supplied by the pipes 11 and 47. The mixture of carbonaceous materials, heavy hydrocarbon oil of and light hydrocarbon oil is subjected to a distillation operation (rectification). The separated or rectified light hydrocarbon oil is discharged through a line 49 into the mixer 41 after cooling through the line 42.

Thus, the light hydrocarbon oil is reused as a solvent in the above operation to transfer the carbonaceous material in the light hydrocarbon oil.

 The mixture of carbonaceous materials and heavy hydrocarbon oil separated in the rectifier 48 of light oil-hydrocarbon is discharged through a line 50 and introduced into the line 11 for supplying heavy hydrocarbon oil. The separated heavy hydrocarbon oil is thus mixed with the blunt heavy hydrocarbon oil and introduced into the solvent deasphalting apparatus 12.

 As clearly explained above, the process for the preparation of synthesis gas of the invention differs advantageously from conventional methods. According to the conventional method, a nelan 7th carbon dobbies and a light hydrocarbon oil derived from contact with a suspension consisting of water and carbonaceous materials formed as by-products in the reaction are mixed with a heavy hydrocarbon oil. partial obyaation with light hydrocarbon oil, ') A rectification is carried out. The mixture obtained from carbonaceous materials and heavy hydrocarbon oil is mixed with the starting heavy hydrocarbon oil. The mixture obtained is introduced directly into a synthesis gas generator and subjected to a partial oxidation reaction.

 Unlike the aforementioned conventional methods for producing a synthesis gas, according to the invention the mixture is subjected to carbonaceous materials and heavy hydrocarbon oil originating from the rectification of light hydrocarbon oil in rectifier 48, with the heavy hydrocarbon oil at the start, in the solvent deasphalting treatment.

The mixture of carbonaceous materials and of asphalt deriving from the solvent deasphalting treatment is conducted in a synthesis gas generator and is subjected to a partial oxidation reaction.

 Thus, according to the invention, the heavy hydrocarbon oil used as starting material for the production of a synthesis gas is not directly subjected to the partial oxidation reaction for gasification. The heavy hydrocarbon oil is first of all subjected to a solvent deasphalting treatment to recover useful hydrocarbon components and the asphalt obtained is used as starting material for the production of synthesis gas. , not only the starting fresh heavy hydrocarbon oil is subjected to the solvent deasphalting treatment, but also the heavy hydrocarbon oil used in the recovery of carbon by-products formed in the production of synthesis gas in the form of the mixture of materials carbonaceous and heavy hydrocarbon oil, is subjected to the solvent deasphalting treatment. Therefore, practically all of the heavy hydrocarbon oil introduced into the production system is subjected to the solvent deasphalting treatment. Consequently, the process for the preparation of synthesis gas of the invention is advantageous from the point of view of the very efficient use of the Varocarbon oil from the start.

 In the preparation process illustrated by the figure of the appended drawing, the line 13 for circulation of the deasphalting solvent and the line 12 for circulation of the solvent for recovering the carbonaceous material are independent. In this case, different hydrocarbon oils can be used, such as deasphalting solvent and as solvent for recovering carbonaceous material. However, when the circulation pipe for the deasphalting solvent and the circulation pipe for the solvent for recovering the carbonaceous material are connected between them, a common solvent (or light hydrocarbon oil) can be used.

 The solvents which can be used in the solvent deasphalting treatment of the invention are light hydrocarbon oils which are conventionally used in the solvent deasphalting treatment of a heavy hydrocarbon oil. Examples of such light hydrocarbon oils are C3 to C6 hydrocarbons such as propane, butane, pentane and hexane. These hydrocarbons can be used alone or in any mixture. When the deasphalting of raffinic hydrocarbons containing as main components C5 to C6 hydrocarbons, such as naphtha, is used as solvent, they can also be used as solvents for recovering carbonaceous matter.

 The invention is illustrated by the following nonlimiting example.

Example
Synthesis gas production is carried out using a process as illustrated in the single figure under the following conditions.

i - heavy starting hydrocarbon oil supplying '' solvent deasphalting apparatus
0 kg of reduced residual oil derived from crude oil u: .ot: in the East having the properties and the impu contents remained indicated in Table 1 and a mixture of 5 kg of carbonaceous material (carbon) and 100 kg of the reduced residual oil t recited (this mixture is obtained by recovering the carbonaceous dobbies formed as by-products in the rartial oxidation with the abovementioned reduced residual oil).

 2 - Solvent deasphalting stage.

A - Solvent: naphtha 4,000 kg
B - Deasphalting conditions, 700 C, 29.4 bars.

 3 - snacks recovered in the solvent deasphalting stage.

A - mixture of deasphalted oil and naphtha: 4,004 kg
B - mixture of asphalt, carbonaceous materials and naphtha: 1,001 kg.

4 - Asphalt and carbonaceous materials recovered from the asphalt rectifier and serving as fuel for the gas generator
Asphalt: 200 kg
carbon dobbies: 5 kg
Properties and content of impurities in asphalt: see
Table 1.

5 - Gas production stage
A - 14 first grade for gas production: 200 kg of the above asphalt and 5 kg of the carbonaceous materials above.

 B - Gasification reagents: 200 kg of oxygen and 90 kg of water vapor.

 C - Gasification conditions: 1 3500 C, 78.4 bars.

 6 - Temperature of introduction of the synthesis gas produced in the carbon scrubber: 2500 C.

 7 - Conditions for recovery of synthesis gas from the carbon washer: 2450 ° C., 76.4 bars.

8 - Synthesis gas produced
A - Quantity: 560 normal m3 (in dry value).

 3 - Composition: see Table 2.

Q - Amount of suspension of carbonaceous materials and water drained from the gas generator and supplying the mixer:
Water 500 kg and carbonaceous materials 5 kg.

 10 - Quantity of naphtha feeding the mixer: 200 kg.

TABLE 1
Ruile Oil, Asphalt
deasphalted start
(residual oil
the reduced)
Density 1.013 0.970 -1.125
Viscosity (m / s. 10-6
at 1000 C) 500 92 -
Sulfur content by weight) 3.9 3.3 6.0
Nitrogen content
(, by weight) 0.3 0.2 0.7
Metal content (Ni + V) (ppm) 90 13 330
TABLE 2
Composition of the synthesis gas produced
Hydrogen gas 42% by volume.

 CO gas 49% in vol.

C 2 gas and others
gas. 9% in flight.

Claims (2)

 1 - Process for the preparation of synthesis gas, characterized in that it comprises the following stages  - solvent deasphalting of a heavy hydrocarbon oil and of a mixture of carbonaceous materials and of heavy h-drocarbon oil using a light hydrocarbon oil that fills deasphalting oil; and  - partial oxidation of the mixture obtained of materials because of zones and of asphalt to produce synthesis gas,  said mixture of carbonaceous materials and heavy hydrocarbon oil being obtained by contacting (1) a suspension containing carbonaceous materials formed as by-products in the partial oxidation of the mixture of carbonaceous materials and asphalt with (2) a hydrocarbon oil l manages, then separation of the oily phase and the aqueous phase of the mixture obtained, addition of heavy hydrocarbon oil to the mixture separated from carbonaceous materials and light hydrocarbon oil and elimination of light hydrocarbon oil from the mixture got.  2 - Process according to claim 1, characterized in that the heavy hydrocarbon oil is a reduced residual oil, a topped crude oil, a whole crude oil or a liquefied coal.  7 - Process according to claim 1, characterized in that light hydrocarbon oil is a liquid hydrocarbon oil containing mainly C3 to C10 paraffinic hydrocarbons.  4 - Process according to claim 1, characterized in that the carbonaceous material is carbon.