RU2434049C2 - Procedure for oil simultaneous extraction and cracking/refining from solid substances - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: solid substances containing oil are supplied into reactor with fluidised layer wherein hydrocarbons are evaporated. Heat consumed for evaporation is generated with an external combustion chamber and with fuel gases together with gaseous hydrocarbons acting as pneumatic carrier of solid substances. Fuel gases reduce partial pressure of gaseous hydrocarbons. By means of pneumatic carrier flow containing solid substances, fuel gas and gaseous hydrocarbons is supplied from a reactor into a reactor of the cyclone, to a separator for extraction of solid substances, and further to a condensation system for gases subjected to condensation. As result of condensation there is produced finish product corresponding to oil. Temperature in a regeneration unit is controlled with moist bituminous sand supplied to the regenerator. Part of cleaned sand is mixed with bituminous sand to reduce heat losses and for homogenisation of sand thus improving raw stock for the reactor. A bed of the reactor, wherein there is generated a fluidised layer of particles, has two diametres. A lower part of the regenerator has diametre less, than an upper part, which decreases rate of gas particles in the upper part of the regenerator. ^ EFFECT: upgraded quality of oil due to generation of lighter fractions; removal of sulphur and heavy metals. ^ 4 cl, 5 dwg

Description

The present invention relates to a method for extracting oil from tar sand (also called oil sand) and / or oil shale and enriching oil in the same method.

Bituminous sand is found in huge quantities in a number of countries, the largest reserves are found in Canada and consist of crude oil and sand of natural origin, lying at different depths. These resources have been the subject of intense research in attempts to develop a technology for extracting oil from a given sand. Thus, there are a number of different technologies.

Alberta's most important mineral resources are oil and gas; they make up more than 90% of Alberta’s income from mining. Alberta produces about two-thirds of Canadian oil and more than three-quarters of its natural gas. Approximately half of Alberta’s oil is produced from numerous oil sands, which are deposits of crude crude oil called bitumen. Alberta's oil sands are the largest known bitumen deposits in the world. Oil sands are found in three main areas of the province: in the Athabasca Valley in the northeast, in the region of Pis-Riser in the north and in the area of Cold Lake in the east of central Alberta. Bitumen is a more expensive mineral than natural crude oil, which naturally flows or is pumped out of the ground. This is due to the fact that in order to obtain crude oil that will have to be refined, its viscous heavy fractions must first be separated from the surrounding sand and water.

In the 1950s - 1960s oil fields were developed in other areas, such as the Peace River Valley and the Lebyazhye Hills south of the Lesser Slave Lake. By the end of the 1960s, the last major oil fields were discovered.

Bitumen, unlike ordinary crude oil found in deep formations, does not contain light fractions that have evaporated over thousands of years. Therefore, bitumen consists of heavy molecules with a density exceeding 1000 kg / dm ³ (less than 10 ANI) and a viscosity 1000 times higher than light oil. In addition, tar sand contains more than 4% sulfur by weight and hundreds of ppm of heavy metals. The content of organic matter in tar sand can vary from 5 to 20% by weight, therefore, the extraction of oil from tar sand includes a huge mass transfer.

The composition of bitumen necessitates its enrichment before it can be processed, like light oil.

The economic potential of these vast resources is explained by the fact that there are a number of different ways to extract oil from tar sands. These technologies include biological, thermal methods, the use of solvents, as well as processes during which oil is washed out of sand by superheated water.

A huge amount of sand (the remaining rock), formed during the extraction of oil from tar sand, leads to the fact that different methods meet a number of environmental restrictions.

Unlike tar sand, oil shale is a shale containing organic matter, known as kerogen, that cannot be washed or dissolved like bitumen in tar sand. To extract oil from oil shale, the latter must be heated to a temperature of 500-600 ° C, as a result of which the cracking of organic matter to liquid products occurs. Like tar sand, oil shale contains a number of undesirable components that cause environmental restrictions. And, as in the case of technologies for extracting oil from tar sand, there are a number of different technologies for extracting oil from oil shale.

The present invention is devoted to an energetically self-sustaining method in which a number of problems known for existing technologies are solved, and which, in addition to oil recovery, better enriches oil with light fractions than any other existing technology, removes about 40% sulfur and about 90% heavy metals . In addition, as a result of this process, the remaining rocks are released with less environmental restrictions, since inorganic matter (sand) is released in the dry state.

This method is a high-speed dry-wet fluidized bed process in which sand is mixed in a reactor to create a fluidized bed with part of the organic matter of tar sand. The flue gases release oil from the sand, together they act as a pneumatic carrier transporting sand and associated gases to the cyclone reactor, where the sand is separated from the gas stream, which is then sent to a condensing system. Part of the condensed oil can be directed back into the stream through spray nozzles for secondary cracking, whereby the oil is extracted and enriched during the process in one stage without the need for enrichment units.

To prevent collisions between particles, since it is necessary to obtain maximum deformation forces between solid particles in a sand stream, flue gases and gaseous hydrocarbons are accelerated and decelerated in a vertical pipeline of variable diameter.

Collisions between particles lead to moderate hydrogenation of oil due to sonoluminescence of microscopic vapor bubbles sandwiched between colliding solid particles. When the vapor bubbles are compressed between rotating irregular particles, the steam undergoes adiabatic compression so that the temperature and pressure in the bubbles increase several thousand times compared with the temperature and pressure of the process as a whole. This compression leads to a supercritical state in which water decomposes into hydrogen and a hydroxyl radical. Hydrogen absorbed on chains of crude oil molecules weakens the bonds in such a way that the collision force with rotating grains of sand can lead to cracking of the molecule and “rupture” of microscopic vapor bubbles. Most hydrogen atoms are then released and reacts again with hydroxyl radicals to form water, but some hydrogen atoms moderately hydrogenate the product.

It is highly desirable to achieve a good sand / oil mixture as early and as fast as possible. The described method of achieving mixing requires the aforementioned acceleration and deceleration of particle flow. The traditional medium used to maintain fluidization and movement of particulate matter in a vertical pipe is steam. However, steam has a damaging effect on very hot solids that can be detected during residual cracking. Under these conditions, steam causes hydrothermal deactivation of the catalyst, for example, a fluidized bed cracking catalyst.

This problem is overcome in the present invention by using the exhaust gases from the fuel-saturated base of the reactor regenerator (CO / CO ₂ and gaseous hydrocarbons) as a carrier gas of particulate matter that will act as oil cracking catalysts.

To test the method, a test bench 2.5 × 2.5 × 3 m in size with a maximum power of 125 kW was built and placed in the laboratory of SINTEF ENERGY RESEARCH AS (Trondheim, Norway).

The plan of the test bench is shown in Fig.3.

Figure 4 depicts a test bench during testing. The energy costs required to process one kilogram of oil sand are defined as:

Q = x _s * c _s * dt + x _o (c _s * dt + r _o ) + x _w * H,

Where

x _s = mass fraction of sand (including metals and sulfur), e.g. 80%,

x _o = mass fraction of oil, for example, 15%,

x _w = mass fraction of water, e.g. 5%,

c _s = specific heat of sand in kJ / kg · K = 1 kJ / kg · K,

c _o = specific heat of oil at an operating temperature in kJ / kg · K = about 2.25 kJ / kg · K,

r _o = heat of vaporization in kJ / kg = approximately 225 kJ / kg,

dt = temperature difference between the operating temperature and the sand feed temperature in K,

N = enthalpy of water at operating temperature in kJ / h = 3500 kJ,

Operating temperature 360 ° C = 633 K,

Feed temperature 90 ° C = 363 K,

dt = 270 K,

Q = 516 kJ / kg, which gives a throughput of a test bench of 872 kg / h of sand containing 130 kg of oil, which implies a throughput of 20 barrels of oil per day.

The tests were carried out with tar sand from the deposits of the Athabasca River Valley. Below are its characteristics and the results obtained:

Density of recovered oil in a fluidized bed reactor: 21 ANI;

Density of recovered oil in a vertical pipeline: 29.3 API;

Density of dried oil at the outlet of the oil condenser: 25.15 ANI;

Coke remaining in waste sand: 1.25% by weight;

Reduction of sulfur content in oil: 45%;

Heavy metal content reduction: 87%;

Energy consumption in% of recoverable oil: 9.3 = approximately 12.5 kg of oil / hour = approximately $ 3.93 per barrel. (At a price of oil of $ 50 per barrel.)

5 shows tar sand, recovered oil, and refined sand remaining after the test experiment.

The process flow diagram is shown further in FIG. 1.

A) denotes the vertical reactor of the apparatus for creating a fluidized bed using a mixer B) located at a certain distance from the bottom of the apparatus. In the space between the bottom and the mixer B), a chamber C) is located to create a fluidized bed, into which flue gases from the combustion chamber D) enter, which can be charged with gas and / or extracted oil. The flue gases are heated and form a fluidized bed of solid particles (sand) E) entering the reactor A). The pressure obtained from the flue gas in the reactor will increase, which will cause pneumatic transport of solid particles and entrained gas, which consists of flue gas, steam and gaseous hydrocarbons, through the vertical pipe JJ) to the cyclone reactor G). The latter is designed in such a way that, unlike a conventional cyclone, solid particles rotate in the cylindrical cyclone body several hundred times before falling into the conical bottom H) and back into the reactor to create a fluidized bed. Superheated steam is fed into the conical bottom of the cyclone using a pipe I) to separate hydrocarbons from the solid particles falling in the cyclone, which enter reactor A) through the elbow.

Oil sand is charged to reactor A) using feed systems Cc) and Dd). The same amount of sand that is fed to reactor A) must be removed from the reactor. This is done through pipeline K), through which sand is transported to the combustion chamber L), where the remaining coke is burned in the fluidized bed by air supplied through M). The exhaust gases from L) pass through the scrubber and the heat recovery system N) before being discharged into the air.

The “purified” solid particles from L) enter the solid / liquid heat exchanger O) and heat the cooled water from the heat exchanger Z), which has come from the water supply pump P). Hot water is then transported to a boiler Q) located in the combustion chamber L). The boiler produces steam, part of which enters the superheater R) located in chamber C) of reactor A). Superheated steam enters the injection nozzles S) for steam spraying of oil, to the bend J) of the cyclone reactor H) and to the bend T) of the separator cyclone U). Cooled "clean" sand can be removed from the heat exchanger O) and used for backfilling into the ground, since it is dry and does not contain any easily evaporating hydrocarbons.

Excess non-superheated steam is discharged through tube V) and used for pre-heating fuel, technological needs or for generating electricity using a steam turbine system.

From the cyclone reactor G) and the separator cyclone U), a gas stream is supplied to a condenser W) set at about 95 ° C, so that most of the gaseous oil is condensed into liquid oil. The gas is condensed by the flow of already extracted oil, since the oil is collected at the bottom of the condenser and is pumped to the heat exchanger Z) with the help of the pump X), where it is cooled by the water coming from the pump P). From the heat exchanger Z), the cooled oil is fed to the top of the condenser and the incoming gaseous oil is condensed. When the oil level in the condenser rises, the product is removed through the tube BB). Non-condensable gas and steam enter the second condenser CC), which is cooled by water supplied from the pump P). Condensed water is removed from the condenser through a tube DD) and collected in a gravitational separator EE). In the gravitational separator EE), light oil fractions coming from the SS oil condenser will be decanted through the tube FF) to the production line from the oil condenser W) and will enter the receiver through the tube AA). Water is drained through the GG tube) into the drain.

Gas that does not condense in the SS condenser, depending on local pollution restrictions, either through the LV pipe) is emitted into the atmosphere, or it enters the gas purification system.

Part of the product is returned to the vertical pipe JJ) through the pipe NN) due to the increased pressure from the pump LL) through the spray nozzle S) connected to the pipe JJ).

The spray nozzle S) receives steam to spray oil from the superheater R).

Excess flue gas generated in the reactor, which is not required for transporting sand to the vertical pipe JJ), can be removed from the reactor through the OO pipe) to a gas scrubber and a heat recovery system (not shown).

When the reactor is heated to the operating temperature by the combustion chamber D) the amount of gas or oil used for combustion can be gradually reduced so that the air supplied to the reactor A) causes internal combustion of the resulting hydrocarbons, and therefore the process will be self-sustaining due to energy, obtained from tar sand itself. Alternatively, the combustion chamber may be filled with a portion of the recovered oil delivered by the LL pump.

To obtain the aforementioned acceleration and deceleration of flow in a vertical pipe, the latter should be given a variable diameter. One of the preferred options is to form a part of the pipeline in the form of a Laval nozzle where the spray nozzle (s) (s) are located (s) either in the narrowest part of the ejector, or where the ejector begins to expand.

When gases associated with solids are introduced into the separator U, the result is the rotation of gases and solids, while the solids are pressed to the inside of the vertical part of the separator due to centrifugal force, and then they are deposited in the conical part of the separator and then enter tube T. Gases, free from solids, leave the separator in its upper part and return them to the condenser W

In General, the method is a high-intensity process with a high energy density due to the high flow rate of gas and sand. High process speeds, causing an intensive energy exchange between sand and oil particles, as well as low partial pressure of gaseous hydrocarbons formed due to flue gases and steam, are the reason that the process can occur in the temperature range 300-500 ° С. In addition to reducing the temperature load and energy consumption, such a low temperature reduces the polymerization of the cracked product.

Figure 2 presents a plant with a capacity of 10,000 barrels per day.

Claims (4)

1. The method of simultaneous extraction and cracking of oil from solids containing oil and solid particles, such as tar sand and oil shale, characterized in that the solids containing oil are fed into a fluidized bed reactor, where the hydrocarbons are evaporated and the heat spent on evaporation, is formed due to the external combustion chamber, and the fact that the flue gases together with gaseous hydrocarbons act as a pneumatic carrier of solids and reduce the partial pressure of gaseous hydrocarbons c, as well as in which a stream consisting of solid particles, flue gas and gaseous hydrocarbons is supplied via a vertical medium through a vertical pipe from the reactor to the cyclone reactor and then to a separator for the extraction of solids, and then to a condensing system for gases capable of to condensation, to obtain, as a result of condensation, the final product, which is oil, where the temperature in the regeneration device is controlled by wet tar sand supplied to the regenerator, and where a part is cleaned sand is mixed with tar sand to reduce heat loss and homogenize sand, which improves the raw materials for the reactor, and where the bed of the reactor in which the fluidized bed of particles is created has two diameters, where the lower part of the regenerator has a smaller diameter than the upper part, which allows reduce the speed of the gas particles in the upper part of the regenerator. 2. A method for the simultaneous extraction and cracking of oil from solids, such as tar sand and oil shale according to claim 1, characterized in that part of the product from the condensing system is returned back to the stream through a vertical pipe through a spray nozzle. 3. A method for the simultaneous extraction and cracking of oil from solids, such as tar sand and oil shale according to claims 1 and 2, characterized in that a vertical pipeline of variable diameter is used to accelerate, slow down and optimize collisions of solid particles for flow. 4. The method for the simultaneous extraction and cracking of oil from solids, such as tar sand and oil shale according to claim 1, characterized in that the sand from which oil was extracted is returned to the combustion chamber to form a fluidized bed, where the remaining coke is burned fed to combustion chamber by air.

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