JP2001139960A - Conversion of heavy oil to light oil and its unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the conversion efficiency to light oil, simultaneously perform processes of a desulfurization and light oil formation and suppress the yield of cokes. SOLUTION: This method for forming the light oil comprises a process of reacting a heavy oil containing sulfur with water in a reactor 14 to which carbon monoxide is supplied under pressure at 380-450 deg.C and 25-35 MPa for converting the heavy oil to the light oil to produce the light oil, a process of separating the obtained product mixture to the light oil, a gas and water, and a process of desulfurizing the sulfur content contained in the gas by adding a sulfur-absorbing agent to the gas. The unit is equipped with a mixer 10 for forming an emulsion of the heavy oil containing sulfur with water, a reactor for converting the heavy oil contained in the heavy oil emulsion to the light oil for yielding the light oil, a pump 19 for supplying pressurized carbon monoxide at 25-35 MPa, a gas, oil and water separator 23 for separating the light oil, the gas and water from the produced mixture, and a desulfurizing vessel 36 for desulfurizing the sulfur content contained in the gas by adding the sulfur- absorbing agent to the separated gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for lightening heavy oil in supercritical water.

[0002]

2. Description of the Related Art Heavy oils containing a large amount of sulfur among petroleum components are becoming less useful because of their limited use. For this reason, a technique for converting heavy oil into clean light oil with many uses has been attracting attention in recent years. In the conventional method for lightening heavy oil, heavy oil is brought into contact with expensive noble metals or metal catalysts such as Ni and Mo under a high-temperature and high-pressure hydrogen gas atmosphere to thermally decompose the heavy oil and hydrogenate it. By doing so, it is converted to light oil and further desulfurized to make clean light oil. However, the above-mentioned conventional method requires a large amount of hydrogen in the thermal cracking and hydrogenation steps of heavy oil, so that hydrogen production equipment is indispensable first, and hydrogen is supplied together with hydrogen gas. There is a problem that the life of the metal catalyst is short due to a poisoning phenomenon in which a substance other than hydrogen such as water is adsorbed or reacted on the metal catalyst surface.

On the other hand, the present applicant has proposed a gasification method for lightening heavy oil by reacting water and heavy oil in supercritical water in order to lighten heavy oil and generate flammable gas. It has been proposed (JP-A-11-246876). This method is a promising method because supercritical water has the effect of suppressing the polymerization of heavy oil and has the advantage that the amount of produced coke is smaller than before. In this gasification method, when lightening heavy oil in supercritical water, a thermal decomposition reaction of the heavy oil or a reaction of adding hydrogen to the primary product occurs.
In the former thermal decomposition reaction, heavy oil is thermally decomposed and depolymerized to generate light oil and flammable gas. In the latter hydrogenation reaction, a hydrogen atom is added to the radical of the primary product generated during the thermal decomposition reaction, whereby the thermal decomposition species is stabilized. In addition, a reaction occurs between a stable molecule that does not thermally decompose and active hydrogen. These reactions are not performed individually, but are performed concurrently and in a complex manner, and lightening proceeds.

[0004]

However, the method disclosed in Japanese Patent Application Laid-Open No. H11-246876 has a main object of producing a flammable gas, and cannot efficiently convert heavy oil to light oil. Was. Also in this method,
The amount of hydrogen required for the hydrogenation reaction of the primary product generated by the thermal decomposition reaction in supercritical water was small, and there was a problem that the lightening of heavy oil could not always be performed sufficiently.
An object of the present invention is to provide a method for lightening heavy oil having a high conversion efficiency to light oil and an apparatus therefor. Another object of the present invention is to provide a heavy oil lightening method and apparatus for simultaneously performing desulfurization and lightening processes. Still another aspect of the present invention is to provide a method and a device for lightening heavy oil, which further suppresses the amount of coke produced.

[0005]

The invention according to claim 1 is
Heavy oil containing sulfur and water at 380-450 ° C, 25-
Reacting in a reactor maintained at 35 MPa to lighten heavy oil to produce light oil, and separating the light oil, gas and water from a mixture containing light oil, gas and water, respectively. A method for lightening heavy oils, comprising supplying carbon monoxide to a reactor at a pressure of 25 to 35 MPa. In the invention according to claim 1, the water gas shift reaction is promoted by pressure-supplying carbon monoxide into the reactor, and sufficient conversion and lightening are performed.

A second aspect of the present invention is the invention of the first aspect, further comprising a step of adding a sulfur absorbent to the separated gas to desulfurize the sulfur contained in the gas. Method. In the invention according to claim 2, by adding the sulfur absorbent to the separated gas, it is possible to recover the exhaust gas containing no sulfur.

As shown in FIG. 1, the invention according to claim 3 is a mixer 10 for producing an emulsion of heavy oil containing sulfur and water, and a heavy oil contained in the heavy oil emulsion produced by the mixer 10. Quality oil at 380-450 ° C, 25-
Reactor 14 for lightening at 35 MPa to produce light oil
A pump 19 for supplying carbon monoxide to the reactor 14 at a pressure of 25 to 35 MPa; and a gas-oil water for separating light oil, gas and water from a mixture containing light oil, gas and water generated in the reactor 14. This is a heavy oil lightening device provided with a separator 23. According to the third aspect of the present invention, the apparatus separates a mixture generated from heavy oil into light oil, gas and water, respectively, and recovers light oil and gas, respectively.

The invention according to claim 4 is the invention according to claim 3, wherein the water separated by the gas oil / water separator 23 is connected to the reactor 14 and the mixer 1 through a pump 42 as shown in FIG.
0 is a heavy oil lightening device configured to supply each of the fuel oils. In the invention according to claim 4, the separated water and dissolved H ₂ S, water which the H ₂ S is dissolved is incorporated sent respectively to the reactor 14, a mixer 10, water as the reaction solvent , H ₂ S are recycled as catalyst.

The invention according to claim 5 is the invention according to claim 3, as shown in FIG. 1, in which a sulfur absorbent is added to the separated gas to desulfurize the sulfur contained in the gas. 36 is a heavy oil lightening apparatus further comprising: In the invention according to claim 5, the separated gas is desulfurized and recovered by the sulfur absorbent.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. The heavy oil lightening apparatus has a mixer 10 for mixing water and heavy oil, as shown in FIG. The water and heavy oil mixed by the mixer 10 become an emulsion. This emulsion is prepared by adding 30 to 60% by weight of water to 100% by weight of heavy oil. The mixer 10 is connected via a pipe 11, a pump 12 and a pipe 13 to a liquid supply port 16 provided below the reactor 14. A heater 10a is provided on the outer periphery of the mixer 10, and a stirrer 10b is provided inside the heater 10a. Reactor 14
Is heat-resistant and pressure-resistant, both ends are sealed and at least 600 ° C
And a pressure of 40 MPa. A heater (not shown) for keeping heat or heating is provided on the outer peripheral portion of the reactor 14.

The conditions in the reactor 14 of the present invention are 380-4
At a temperature of 50 ° C. and a pressure of 25-35 MPa. Preferably it is 380-420 degreeC and 25-30 MPa.
If the temperature is lower than 380 ° C. or less than 25 MPa, lightening is insufficient, and if the temperature is higher than 450 ° C., a problem that a large amount of coke is generated occurs. On the other hand, if it exceeds 35 MPa, the reactor 14 will be overloaded. A characteristic configuration of the present invention is that a CO supply port 17 is provided below the reactor 14, and a booster pump 19 is connected to the supply port 17 via a pipe 18. CO is supplied at the same pressure as in the reactor 14. The amount of CO to be supplied is such that the molar ratio to carbon contained in the liquid to be treated (hereinafter referred to as CO / C) is 0.1 to 0.1.
Preferably it is 0.4.

At the top of the reactor 14 is a product mixture outlet 21.
However, a water supply port 22 is provided at the bottom. A gas-oil separator 23 is connected to the outlet 21 via a pipe 24. A cooler 26 is provided in the middle of the pipe 24. The gas-oil-water separator 23 is a vertically long, closed chamber, and includes a gas outlet 23a, a light oil outlet 2 in the upper, middle, and lower stages, respectively.
3b, a water outlet 23c is provided. A first pipe 27 is connected to an outer wall of the separator 23 between a gas outlet 23a and a light oil outlet 23b. In the middle of the pipe 27, the first
A level gauge 28 is provided, and the first level gauge 28 is connected to a control input of a control device 29. A second pipe 31 is connected between the light oil outlet 23b and the water outlet 23c. A second level gauge 32 is provided in the middle of the pipe 31, and the level gauge 32 is connected to a control input of the control device 29. The control output of the control device 29 is connected to solenoid valves 34, 37, and 39 to be described later. Also, the first pipe 27 communicates between the upper stage and the middle stage of the separator 23,
Further, the second pipes 31 are respectively provided so as to communicate the middle stage and the lower stage of the separator 23.

The gas outlet 23a has a pipe 33, a solenoid valve 34,
Is connected to the lower part of the desulfurizer 36 via the. Light oil outlet 2
3b is connected to the solenoid valve 37. The water outlet 23c provided at the bottom of the separator 23 is connected to a pump 42 via a pipe 38, a solenoid valve 39, and a pipe 41. The pump 42 connects a pipe 43, a distribution valve 45, and a preheater 44. Through a water supply port 22 provided at the bottom of the reactor 14. Distributing valve 4
A conduit 46 is connected between the mixer 5 and the mixer 10. A supply port 46 for supplying a sulfur absorbent is provided at the bottom of the desulfurizer 36, and a discharge pipe 47 is provided above the desulfurizer 36, and a pressure reducing valve 48 is connected to the discharge pipe 47. Sulfur absorbents include NaOH, KOH, Ca (OH) ₂ , Ba (O
H) An aqueous solution containing an alkali hydroxide represented by _{2 and the} like, and an aqueous solution containing an alkylamine such as methylethylamine, diethylamine, diisopropylamine and the like are included.

In the apparatus configured as described above, heavy oil and water are cooled to less than 100.degree.
a (for example, 0.5 MPa) to prepare a liquid to be treated in the form of an emulsion. The liquid to be treated is supplied from the mixer 10 into the reactor 14 through the liquid supply port 16 through the pipe 11, the pump 12, and the pipe 13. CO is supplied into the reactor 14 from the CO supply port 17 at the same pressure as the pressure in the reactor via the booster pump 19. The temperature in the reactor 14 is 380-450 ° C
When the pressure is kept in a supercritical state of water at 25 to 35 MPa (for example, 25 MPa), the heavy oil in the liquid to be treated is lightened and CO, H ₂ , CH ₄ , CO ₂
Gas is generated. That is, the heavy oil in the liquid to be treated is thermally decomposed, and hydrogen is added to the primary product generated by the decomposition. As a result, a mixture of light oil, water, and gas is generated from the liquid to be treated.

This production reaction is a water gas shift reaction described below. _{CO + H 2 O → H 2} + CO 2 ...... (1) water-gas shift reaction, the reaction proceeds a hydrogen sulfide as a catalyst. That is, the heavy oil in the liquid to be treated generates sulfur and unstable small molecules by a thermal decomposition reaction in supercritical water. This sulfur reacts with hydrogen in an unstable low molecule to generate hydrogen sulfide as shown in the following formula (2). S + H ₂ → H ₂ S (2) Hydrogen sulfide reacts with carbon monoxide to generate active hydrogen as shown in the following formula (3), and increases the efficiency of converting heavy oil to light oil. improves. The generated sulfur compound (COS) reacts with water to return to hydrogen sulfide as shown in the following formula (4), and is recycled as a catalyst.

CO + H ₂ S → COS + H ₂ (3) COS + H ₂ O → H ₂ S + CO ₂ (4) The lightened product mixture is taken out from the product mixture outlet 21 and cooled. The gas is cooled to less than 100 ° C. (for example, 60 ° C.) by the device 26 and sent to the gas oil water separator 23. In the separator 23, the mixture is separated into light oil, water, and gas.
When the resulting mixture is allowed to stand inside the separator 23, the lower portion of the separator 23 in the order of the specific gravity has an aqueous phase, a light oil phase in the middle stage,
A gas phase is formed in each upper stage. In order to always keep the height of the gas-light oil and light oil-water interfaces constant, the control device 29 uses first and second level gauges 28 and 32 provided outside the separator 23 as sensors and electromagnetic valves. 34, 3
7 and 39 are controlled. That is, when the gas amount increases as compared with the amount of water or light oil, and the gas-light oil interface rises, the solenoid valve 34 is opened. Conversely, the amount of gas decreases,
When the gas-light oil interface goes down, solenoid valve 37 or 3
Release 9 The separated gas is sent to a desulfurizer 36, and the sulfur contained in the gas is removed by a sulfur absorbent to be recovered as a fuel gas. At the bottom of the desulfurizer 36, sulfate generated by the gas and the sulfur absorbent settles. This sulfate is periodically removed from the desulfurizer 36. The separated water has dissolved H ₂ S, water which the H ₂ S is dissolved is fed respectively to the reactor 14 and the mixer 10 from the pump 42 via the distribution valve 45, the water is the reaction solvent As
H ₂ S is reused as a catalyst.

[0017]

Next, examples of the present invention will be described together with comparative examples. <Example 1> A heavy oil of residual oil obtained by refining crude oil was used as a sample. Using a device having a structure similar to that of FIG. 1, the heavy oil is mixed with water to prepare a liquid to be treated as a heavy oil emulsion, and the liquid to be treated is supplied into the reactor. CO was supplied so that the CO / C molar ratio became 0.1. The reactor was kept at 380 ° C. and 25 MPa to lighten the liquid to be treated. Light oil and gas generated by the lightening were retained in the reactor for 5 minutes. Examples 2 to 4 and Comparative Examples 1 and 2 were also lightened by using an apparatus having a structure similar to that of FIG.

<Example 2> The liquid to be treated was lightened under the same reaction conditions as in Example 1 except that CO was supplied so that the CO / C molar ratio became 0.3, and the light produced by the lightening was used. The oil was kept in the reactor for 5 minutes. <Example 3> Except that the pressure of the reactor was 35 MPa,
CO was supplied in the same manner as in Example 1, and the liquid to be treated was lightened under the same temperature conditions as in Example 1. The light oil produced by the lightening was retained in the reactor for 5 minutes. <Example 4> CO was supplied in the same manner as in Example 1,
The liquid to be treated was lightened under the same reaction conditions as described above. The light oil produced by the lightening was retained in the reactor for 30 minutes.

Comparative Example 1 The liquid to be treated was lightened under the same reaction conditions as in Example 1 except that CO was not supplied. The light oil produced by the lightening was retained in the reactor for 5 minutes. <Comparative Example 2> CO was supplied in the same manner as in Example 1 except that the temperature of the reactor was set to 480 ° C, and the liquid to be treated was lightened under the same pressure conditions as in Example 1. The light oil produced by the lightening was retained in the reactor for 5 minutes.

<Comparative Evaluation> The desulfurization rate of the produced light oil, the formation rate of coke, and the hydrogen deposition rate per carbon of the light oil (hereinafter referred to as H / C) were measured. Examples 1-4
Table 1 shows the results of Comparative Examples 1 and 2. The H / C of the residual oil used as the heavy oil sample was 1.47, and the sulfur content was 5.6% by weight.

[0021]

[Table 1]

In Examples 1 to 4 and Comparative Example 2, the H / C of the light oil produced was lower than that of Comparative Example 1 in which no carbon monoxide was added.
Is high, indicating that the addition of carbon monoxide into the reactor promotes lightening. However, in Comparative Example 2, since the temperature in the reactor was set to 480 ° C., which was higher than the optimum temperature range for lightening, excessive thermal decomposition reaction occurred and a large amount of coke-containing residue was generated.

[0023]

As described above, the sulfur contained in the heavy oil is used as a catalyst for the water gas shift reaction, and the carbon monoxide is specially supplied to the reactor, so that the water gas shift reaction proceeds to produce light oil. The conversion efficiency can be increased, and the desulfurization and lightening processes can be performed simultaneously.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for lightening heavy oil according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 mixer 14 reactor 19 pump 23 gas-oil-water separator 36 desulfurizer

Continued on the front page F term (reference) 4D020 AA04 BA01 BA08 BA16 BB03 CB03 CC05 DA01 DB15 DB20 4H029 AA11 AB06 AB10 AB11 AB12 AC03 AC04 AC12 AD01 AE01 DA01 DA02 DA06

Claims (5)

[Claims] 1. A method according to claim 1, wherein said heavy oil containing sulfur is mixed with water at 380-4.
Reacting in a reactor (14) maintained at 50 ° C. and 25 to 35 MPa to lighten the heavy oil to produce light oil; and light oil and gas from a mixture containing the light oil, gas and water. A heavy oil comprising the steps of: separating carbon monoxide into the reactor (14) at a pressure of 25 to 35 MPa. Method. 2. The method for lightening heavy oil according to claim 1, further comprising a step of adding a sulfur absorbent to the separated gas to desulfurize sulfur contained in the gas. 3. A mixer (10) for producing an emulsion of heavy oil and water containing sulfur, and a heavy oil contained in the heavy oil emulsion produced by the mixer (10) at 380-450 ° C. A reactor (14) for lightening at 25 to 35 MPa to produce light oil, a pump (19) for supplying carbon monoxide to the reactor (14) at a pressure of 25 to 35 MPa, and a reactor (14) Gas oil water separator (23) for separating light oil, gas and water from the mixture containing light oil, gas and water generated in step (23)
A heavy oil lightening device comprising: 4. A pump for pumping water separated by the gas oil / water separator (23).
The heavy oil lightening apparatus according to claim 3, wherein the apparatus is configured to supply the heavy oil to the reactor (14) and the mixer (10) via the (42). 5. The heavy oil lightening device according to claim 3, further comprising a desulfurizer (36) for adding a sulfur absorbent to the separated gas to desulfurize sulfur contained in the gas.