CN109181754B - Water-containing and sand-containing unconventional petroleum hydrothermal upgrading and separation and purification method - Google Patents

Abstract

The invention discloses a method for hydrothermal upgrading, separation and purification of water-bearing sand-bearing unconventional oil. The combined process of hydrothermal treatment and high temperature in-situ filtration is used to dehydrate and de-sand, separate and purify raw oil from unconventional oil, and at the same time, the oil is subjected to dehydration and desanding. Hydrothermal quality improvement, especially to improve its pipeline performance. The technology makes full use of the characteristics of unconventional petroleum thermally modified oil with low viscosity and good fluidity. The whole process does not need to add any solvent, which effectively reduces energy consumption and environmental pollution.

Description

Water-containing and sand-containing unconventional petroleum hydrothermal upgrading and separation and purification method

Technical Field

The invention belongs to the field of energy and chemical engineering, and particularly relates to a hydrothermal upgrading, separating and purifying method for water-containing and sand-containing unconventional petroleum.

Background

With the increasing scarcity of light petroleum resources, the status of unconventional petroleum (including heavy oil, oil sand bitumen, coal-to-liquids, shale oil, etc.) in the world energy structure is becoming more and more important. Typically, unconventional petroleum resources are associated with large amounts of water and sand, greatly increasing the difficulty of oil recovery and processing costs. For example, oil sands (oil crops) is an important unconventional petroleum resource: canadian oil sands bitumen contributed 2,650,000 barrels per day of crude oil to the world crude oil market in 2017, from which it can be seen that oil sands bitumen plays an important role in world energy. The oil sand is composed of bitumen oil, water, clay minerals, sand grains and the like, and how to separate water and mineral particles from an oil phase is an important problem in the field of oil sand oil processing and utilization. At present, the industrially mature oil sand treatment process is a hot alkali water washing method, and asphalt foam (bitumen froth) is an important intermediate product in the process (the water content is 10-30 wt%, the solid content is 5-15 wt%, and the asphalt oil content is 55-85 wt%). The method for reducing the viscosity of the oil phase and generating phase separation by adding the solvent is a main method adopted for dewatering and desanding in asphalt foam at present, but the method has a series of problems of high solvent adding and recycling cost, high energy consumption, difficult tailing treatment, serious environmental pollution and the like. The search for a high-efficiency, environment-friendly and economic method for purifying and separating fuel oil is an important subject in the field of oil sand oil processing.

Pipeline transportation is a main channel for oil sand bitumen oil sale, and currently, pipeline transportation of bitumen oil under the condition of avoiding or reducing solvent addition by reducing bitumen oil viscosity through mild upgrading is a great hotspot of oil sand research. The research on the mitigation and quality improvement of the asphalt oil mostly uses the asphalt oil obtained by treating asphalt foam with a solvent as a raw material, and realizes the viscosity reduction and pipe transportation of the asphalt oil by one or a combination of heat treatment, deasphalting and solvent addition. The invention provides a concept of combining tar oil dehydration and desanding with viscosity reduction and quality improvement from a water-containing and sand-containing intermediate tar oil product, improves the quality of tar oil while separating and purifying the tar oil, and aims to simplify the treatment process, improve the economic benefit and reduce the environmental pollution. The method is generally suitable for unconventional petroleum resources containing water and sand, and has important significance for efficient processing and utilization of the unconventional petroleum.

Disclosure of Invention

The invention aims to provide a processing method for unconventional petroleum containing water and sand, which can organically combine viscosity reduction and quality improvement with separation and purification, thereby simplifying the processing process flow of unconventional petroleum, reducing the operation and processing cost and reducing the environmental pollution.

The technical scheme for realizing the purpose of the invention is as follows:

a hydrothermal upgrading, separating and purifying method for unconventional petroleum containing water and sand comprises the following steps

(1) Carrying out mild hydrothermal treatment on the unconventional petroleum containing water and sand to reduce the viscosity of an oil phase and accelerate the separation of solid particles from the oil phase;

(2) discharging gas generated after hydrothermal reaction, and removing emulsified water in the raw materials;

(3) and carrying out in-situ hot filtration on the residual oil obtained after dehydration to remove solid particles in the raw materials, and collecting the product oil.

The unconventional petroleum is asphalt foam obtained after washing oil placer with water, asphalt oil obtained after extracting the oil placer without water, heavy oil or coal-made oil.

Furthermore, the mild heat treatment reaction temperature is 290-400 ℃, and the preferable reaction temperature is 330-380 ℃.

The aperture of the filter medium used in the heat filtration is 0.5-4.5 micrometers, and preferably 1-2 micrometers.

The invention has the beneficial effects that: the subcritical water environment is promoted under the action of heat by utilizing the original moisture in the water-containing sand unconventional petroleum, so that the viscosity reducing effect of the petroleum component is improved, the reduction of the pipeline transportation cost of the heavy oil (bitumen oil) is facilitated, and the economic benefit is improved. Under thermal conditions, emulsified water in unconventional petroleum, which is difficult to remove by conventional methods, is gasified to separate phases, thereby enabling efficient separation of emulsified water in the form of gas. Meanwhile, the hydrothermal reaction weakens the interaction between the solid particles and the oil phase, and is favorable for removing the solid particles. By utilizing the characteristics of low viscosity and good fluidity of the thermal modified oil, the in-situ thermal filtration of the dehydrated residual oil is carried out under the condition of not adding any solvent, thereby removing solid particles. The method organically combines the quality improvement and the purification of the asphalt, thereby effectively simplifying the process flow and saving the equipment and the operation cost. The invention does not need solvent adding and recovering units in the conventional separation process, thereby reducing energy consumption and environmental pollution. The invention provides a new way for the efficient cleaning and utilization of unconventional petroleum resources.

Drawings

FIG. 1 is a schematic diagram of a hydrothermal upgrading and separation and purification method of water-containing and sand-containing unconventional petroleum.

Detailed Description

The method can be used for obtaining clean petroleum products and simultaneously improving the quality of the petroleum products, and the method is further explained by combining with specific embodiments.

A hydrothermal upgrading, separating and purifying method for unconventional petroleum containing water and sand comprises the following specific process flows:

(1) the process comprises a hydrothermal treatment unit, a condensation phase separation unit and a high-temperature filtration unit, wherein the hydrothermal treatment unit takes asphalt foam as a raw material, gas generated after hydrothermal reaction is discharged into the condensation phase separation unit, and the remainder enters the high-temperature filtration unit.

(2) The hydrothermal treatment unit is a high-temperature high-pressure reactor. As the reactor temperature increases, the hydrothermal reaction of the aqueous sand-containing unconventional petroleum phase occurs: on one hand, the emulsion breaking function is exerted, so that emulsified water which is difficult to remove in the raw materials is separated and discharged in a gas form; on the other hand, this reaction causes a light cracking reaction of the oil, which lowers the oil phase viscosity. The hydrothermal reaction also facilitates the separation of the solid particles from the oil phase.

(3) The condensation phase separation unit comprises a gas phase condenser and a liquid phase separator. After hydrothermal treatment, gas phase products are discharged and enter a condenser, gas which is not condensed into liquid is collected and recovered, the liquid obtained by cooling and condensation enters a liquid phase separator, after sedimentation and stratification, an upper layer light oil phase is collected or mixed into an oil product, and lower layer condensed water is recovered.

(4) The high-temperature filtering unit is a high-temperature resistant filter. And after the reaction gas phase of the hydrothermal treatment unit is discharged, directly feeding the residual oil into a high-temperature filtering unit for in-situ hot filtering to remove solid particles, wherein the filtrate is product oil.

The present invention is further illustrated by, but is not limited to, the following examples.

Example 1

A hydrothermal upgrading, separating and purifying method for unconventional petroleum containing water and sand comprises the following steps:

(1) 2.5 kg of asphalt foam (containing 75 wt% of asphalt oil, 19 wt% of water and 6 wt% of solid particles) was charged into a stirred autoclave, and the air in the autoclave was replaced with nitrogen purge three times to ensure that the reaction process was an inert gas atmosphere. The thermostat temperature was set at 320 ℃, the furnace and stirrer were turned on (350 rpm), the temperature was raised from room temperature to the set temperature and held for 30 minutes, and then the furnace was turned off.

(2) The condenser refrigeration unit was turned on and then the gas vent valve was opened and the reactor gas was vented to the condenser. Introducing uncondensed gas released from the tail end of the condenser into a fume hood, allowing the condensed liquid to enter a separator and standing for 1 hour, opening a valve at the lower end of the separator to release and collect a water layer, and collecting light oil at the upper layer after the water layer is drained, wherein the obtained water and light oil are 0.45 kg and 0.21 kg respectively.

(3) When the temperature of the reaction kettle is reduced to about 200 ℃, a valve at the bottom end of the reaction kettle is opened, heat filtration is carried out under the pressure of 1 MPa nitrogen, the aperture of a used filter medium is 0.5 micron, after the filtration is finished, the solid and water content in the asphalt oil product is collected and measured, and through detection, the water content is 0.04 wt% and the solid particle content is 0.18 wt% in 1.2 kg of the collected asphalt oil product.

Example 2

A hydrothermal upgrading, separating and purifying method for unconventional petroleum containing water and sand comprises the following steps:

(1) 1.9 kg of oil sand oil (containing 97.2 wt% of asphalt, 2 wt% of water and 0.8 wt% of solid particles) obtained by anhydrous extraction (using cyclohexane as a solvent) and 0.19 kg of cyclohexane were added to a stirred high-temperature high-pressure reaction kettle, and the air in the reaction kettle was replaced by nitrogen purging three times to ensure that the reaction process was an inert gas atmosphere. The thermostat temperature was set to 360 ℃, the furnace and stirrer were turned on (350 rpm), the temperature was raised from room temperature to the set temperature and held for 30 minutes, and then the furnace was turned off.

(2) The condenser was opened, the gas discharge valve was opened and the gas in the reactor was discharged into the condenser. Introducing uncondensed gas released from the tail end of the condenser into a fume hood, allowing the condensed liquid to enter a separator and standing for 1 hour, opening a valve at the lower end of the separator to release and collect a water layer, and collecting light oil at the upper layer after the water layer is drained, wherein the obtained water and light oil are 0.02 kg and 0.37 kg respectively.

(3) When the temperature of the reaction kettle is reduced to about 200 ℃, a valve at the bottom end of the reaction kettle is opened, heat filtration is carried out under the pressure of 1 MPa nitrogen, the aperture of a used filter medium is 0.5 micron, after the filtration is finished, the solid and water content in the asphalt oil product is collected and measured, and through detection, the water content is 0.01 wt% and the solid particle content is 0.06 wt% in 1.4 kg of the collected asphalt oil product.

Claims (2)

1. A quality-improving and purifying method of a water-containing sand-containing unconventional petroleum subcritical hydrothermal treatment-in-situ thermal filtration combined process is characterized by comprising the following steps: the steps are as follows

(1) Carrying out mild hydrothermal treatment on the water-containing sand-containing unconventional petroleum at 320-360 ℃, and reducing the viscosity of the oil phase and weakening the bonding effect of solid sand particles and the oil phase by utilizing the subcritical water environment promoted by the raw water in the water-containing sand-containing unconventional petroleum;

(2) after hydrothermal treatment, discharging gas generated in the hydrothermal reaction process, condensing the gas, and then feeding the condensed gas into a liquid phase separator to obtain light oil and water, and removing emulsified water in the unconventional petroleum raw materials;

(3) after the gas is exhausted, the residue is subjected to in-situ heat filtration to form a subcritical hydrothermal treatment-in-situ heat filtration combined process, solid sand grains in the unconventional petroleum raw material are removed, filtrate is collected to obtain dehydrated and desanded petroleum,

the unconventional petroleum is asphalt foam obtained after washing oil placer with water, asphalt oil obtained after extracting the oil placer without water, heavy oil or coal-made oil.

2. The upgrading and purifying method of the water-containing sand-containing unconventional petroleum subcritical hydrothermal treatment-in-situ thermal filtration combined process according to claim 1, characterized by comprising the following steps of: and (3) the aperture of the filter medium used in the in-situ heat filtration is 0.5-2 microns.

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