Method and system for controlling ultra-low emission of vocs in oil and gas

Abstract

The application provides a method and system for controlling VOCs ultra-low emission of oil gas, wherein the oil product contains at least one light component of C1, C2 and C3. The method comprises the following steps: step S1, stripping of light components of oil product: stripping the light components in the oil product, taking the stripped light components as fuel gas backup, and taking the oil product after stripping the light components as an adsorbent; step S2, VOCs elution of oil gas: contacting the oil gas to be treated with the adsorbent in step S1 to adsorb the VOCs components in the oil gas to be treated, and obtaining rich oil containing VOCs components and low-concentration oil gas after absorption; and step S3, incineration treatment: multi-stage mixing and multi-stage combustion treatment of the fuel gas obtained in step S1 and the low-concentration oil gas obtained in step S2 and air, so as to obtain an emission tail gas with ultra-low VOCs.

Description

Technical Field

[0001] This invention relates to the field of oil and gas processing, and specifically to a method and system for controlling ultra-low emissions of VOCs from oil and gas products. Background Technology

[0002] Some oil products, such as crude oil, contain a high content of C1 to C3 light components in their oil and gas. Current conventional recovery processes (such as adsorption, absorption, and condensation) cannot effectively absorb these light components, resulting in high levels of light component emissions. Furthermore, these oil products have high sulfur content and significant amounts of gums and waxes, leading to a situation where the VOCs (volatile organic compounds) they contain include not only a large amount of light components but also a certain amount of heavy and corrosive components. Therefore, current oil and gas processing equipment for crude oil products faces the following problems:

[0003] (1) The emission indicators fluctuate greatly, and the content of C1, C2 and C3 components fluctuates greatly with the oil. These components will completely penetrate the adsorption device, resulting in serious emissions exceeding the standard.

[0004] (2) The activated carbon used in the adsorption device cannot operate safely and stably for a long period of time;

[0005] (3) Conventional incineration devices, such as regenerative combustion and catalytic combustion, require the waste gas concentration to be reduced to below the safe concentration (25% LEL) in order to achieve safe waste gas treatment;

[0006] (4) Some direct combustion devices require a large amount of supplementary natural gas or similar fuel gas, which leads to complex auxiliary engineering and high energy consumption of the system.

[0007] In summary, due to the complexity of the composition of oil and gas containing C1 to C3 grades, achieving ultra-low emissions (mg level) in the field of VOCs treatment is very difficult.

[0008] Furthermore, in the storage of related oil products, especially crude oil, the storage facilities and terminals often lack complete utilities, such as supporting facilities for diesel and natural gas. Adopting processes requiring such utilities would cause significant problems and inconveniences; therefore, there is an urgent need to develop a process method and related control system with low utilities requirements. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method and system for controlling ultra-low VOC emissions from oil products and oil gas. The method uses oil products stripped of light components as adsorbents to adsorb high-concentration oil gas, and directly combusts the adsorbed heavy components, using the stripped light components as fuel gas. This method achieves low energy consumption, simple utility support, safe equipment, and stable emission compliance.

[0010] This invention provides a method for controlling ultra-low VOC emissions from petroleum products, wherein the petroleum products contain light components comprising at least one of C1, C2, and C3, and the method includes the following steps:

[0011] Step S1, Light component stripping of oil: The light components in the oil are stripped off, the stripped light components are used as fuel gas, and the oil after stripping the light components is used as an adsorbent.

[0012] Step S2, VOCs elution of oil and gas: The oil and gas to be treated is contacted with the adsorbent in step S1 to adsorb the VOCs components in the oil and gas to be treated. After absorption, a rich oil containing VOCs components and a low-concentration oil and gas with the VOCs components removed are obtained.

[0013] Step S3, Incineration treatment: The fuel gas obtained in step S1, the low-concentration oil gas obtained in step S2, and air are mixed in multiple stages and subjected to multi-stage combustion treatment to obtain ultra-low VOCs emission exhaust gas.

[0014] Furthermore, the multi-stage mixing and multi-stage combustion process in step S3 includes:

[0015] Step a: Mix the fuel gas with the low-concentration oil and gas and perform primary activation to obtain pre-combustion gas;

[0016] Step b: Mix the pre-combustion gas with air and then perform primary combustion to obtain pre-emission gas; and

[0017] Step c: The pre-emission gas is mixed with a low-temperature medium for a second time and then introduced with combustion-supporting gas for secondary combustion, thereby obtaining ultra-low VOCs emission exhaust gas.

[0018] Furthermore, the primary activation in step a is performed by the following method:

[0019] The fuel gas and the low-concentration oil gas are heated to a temperature between 50 and 400°C.

[0020] and / or

[0021] The fuel gas and the low-concentration oil and gas are catalytically activated.

[0022] Furthermore, the light component stripping in step S1 is performed in at least one of the following ways:

[0023] (1) Heating, controlling the separation operation temperature between 0℃ and 200℃;

[0024] (2) Negative pressure: The separation operation pressure is controlled between -1.0 MPaG and 0.01 MPaG, and

[0025] Step S1 further includes:

[0026] The obtained fuel gas is fed into a buffer device for caching.

[0027] Furthermore, prior to step S2, the method further includes: step S2-0, oil-gas compression: compressing the oil-gas to be processed at an operating pressure between 0 MPaG and 2.0 MPaG; and / or

[0028] Before step S3, there is also step S3-0, which controls the flow rate of the low-concentration oil and gas and the fuel gas, so that the concentration of the low-concentration oil and gas and the fuel gas are both between 10 and 600 g / m3.

[0029] Furthermore, the method also includes step S4, condensing and collecting the rich oil from step S2 and returning it to step S1 for stripping and subsequent use, wherein the condensation operation temperature is between -100°C and 30°C.

[0030] According to a second aspect of the present invention, a system for controlling ultra-low emissions of VOCs from petroleum products, wherein the petroleum products contain C1 to C3 components, characterized in that the system comprises:

[0031] A fuel gas production unit includes a first gas-liquid separator, which has an oil inlet and an upper outlet and a lower outlet.

[0032] Oil and gas scrubbing unit, comprising:

[0033] A scrubbing tower is provided with a first oil and gas inlet at the bottom of the tower body, an adsorbent inlet at the top of the tower body, a low-concentration oil and gas outlet at the top of the tower, and a rich oil outlet at the bottom of the tower. The adsorbent inlet is connected to the lower outlet of the first gas-liquid separation device through a pipeline.

[0034] Combustion unit, comprising:

[0035] A gas mixing device, the gas mixing device including a fuel gas inlet and a low-concentration oil and gas inlet connected to the low-concentration oil and gas outlet, and a pre-combustion gas outlet, wherein the fuel gas inlet of the gas mixing device is connected to the upper outlet of the first gas-liquid separator;

[0036] The combustion device includes a pre-combustion gas inlet, an air inlet, an ignition port, a cryogenic medium inlet, and a pre-discharge gas outlet, wherein the pre-combustion gas inlet and the pre-combustion gas outlet are connected.

[0037] Furthermore, the fuel gas production unit also includes:

[0038] A second gas-liquid separator is disposed between the upper outlet of the first gas-liquid separator and the fuel gas inlet. The upper end of the second gas-liquid separator has a fuel gas outlet communicating with the fuel gas inlet, and the lower end of the second gas-liquid separator has a separated liquid outlet.

[0039] A buffer device is provided, which is disposed between the upper outlet of the first gas-liquid separator and the fuel gas inlet.

[0040] The first gas-liquid separation device includes a heating device and / or a vacuum generating device.

[0041] Furthermore, the oil and gas scrubbing unit also includes a compression device, which is located at the upstream end of the oil and gas inlet of the scrubbing tower; and / or

[0042] A flow control valve is installed on the pipeline between the low-concentration oil and gas outlet and the low-concentration oil and gas inlet.

[0043] Furthermore, a condensation device is provided outside the rich oil outlet, and the outlet of the condensation device is connected to the oil inlet through a pipeline. A reflux pump is provided on the pipeline between the lower outlet and the oil inlet.

[0044] This invention utilizes the inherent absorption properties of oil and its presence of light components to utilize these light components as fuel in subsequent combustion processes. Furthermore, the uneven distribution of combustibles in the exhaust gas (oil gas to be treated) leads to instability during combustion. By transferring the combustibles from the exhaust gas to the oil, further volatilization produces pure fuel, thereby achieving stable combustion. Using stripped, de-lightened oil as an adsorbent eliminates the need for introducing other adsorbents and unnecessary replacements, ensuring long-term safe and stable operation. Moreover, using light components as subsequent fuel gas eliminates the need for large-scale supplementation with similar fuel gases such as natural gas, reducing engineering complexity and system energy consumption. This invention also utilizes multi-stage mixing and multi-stage combustion to ensure complete combustion of the fuel gas and low-concentration oil gas, further reducing the VOCs and nitrogen oxide content in exhaust emissions.

[0045] The system of this invention removes light components from oil products through a fuel gas production unit for use as fuel reserves; at the same time, the absorption effect of the oil products after the light components are extracted is greatly improved, and they are used as adsorbents in an oil and gas washing unit; the adsorbents can be recycled or used for a single wash; after washing, the uniformity of oil and gas concentration is improved, avoiding the impact of large fluctuations in oil and gas on the combustion device.

[0046] The method and system of this invention are simple, convenient, and highly safe. They collect some volatile components and combine them with the tolerance of direct combustion devices to fluctuations in oil and gas concentrations, achieving low energy consumption, simple utility support, safe equipment, and stable emissions that meet standards. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a first embodiment of the system for controlling ultra-low emissions of VOCs in oil and gas according to the present invention;

[0048] Figure 2 This is a schematic diagram of a second embodiment of the system for controlling ultra-low emissions of VOCs in oil and gas according to the present invention;

[0049] Figure 3 This is a schematic diagram of a third embodiment of the system for controlling ultra-low emissions of VOCs in oil and gas according to the present invention.

[0050] Diagram labels: 1-Fuel gas production unit, 11-Oil inlet, 12-First gas-liquid separator, 121-Upper outlet, 122-Lower outlet, 123-Heating device, 124-Vacuum generator, 13-Second gas-liquid separator, 131-Fuel gas outlet, 132-Separated liquid outlet, 2-Oil-gas washing unit, 21-Washing tower, 211-First oil-gas inlet, 212-Adsorbent inlet, 213-Low-concentration oil-gas outlet, 214-Rich oil outlet, 3-Combustion unit, 31-Gas mixing device, 311-Fuel gas inlet, 312-Low-concentration oil-gas inlet, 313-Pre-combustion gas outlet, 32-Combustion device, 321-Pre-combustion gas inlet, 322-Ignition port, 323-Cryogenic medium inlet, 324-Tail gas outlet, 325-Oxidant gas inlet, 4-Compression device, 5-Flow control valve, 6-Condensation device, 7-Reflux pump. Detailed Implementation

[0051] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The principles and features of the present invention are described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0052] It should be noted that the oil and gas to be treated mentioned in this invention originates from oil evaporation during oil loading or storage and transportation. The VOCs components to be treated mentioned in this invention include light hydrocarbon components (i.e., light components containing at least one of C1, C2, and C3). The typical composition of the oil products described in this invention is crude oil products and the oil and gas volatilized from crude oil products.

[0053] A first aspect of the present invention provides a method for controlling ultra-low emissions of VOCs from petroleum products. The petroleum product may be, for example, crude oil, fuel oil, liquefied petroleum gas, etc., containing light components comprising at least one of C1, C2, and C3. Specifically, the method includes the following steps:

[0054] Step S1, Light Component Stripping of Oil: The light components in the oil are stripped off. The stripped light components are used as fuel gas and the oil after light component stripping is used as an adsorbent. This eliminates the need for external fuel gas supply and additional adsorbent in the subsequent adsorption and combustion processes, avoiding the complex process of subsequent adsorbent recovery and saving a significant amount of energy.

[0055] Furthermore, in some embodiments, the above-mentioned light component stripping treatment employs at least one of the following methods: (1) heating, with the temperature controlled between -40°C and 200°C, preferably between 0°C and 120°C; (2) negative pressure, with the pressure controlled between -1.0 MPaG and 0.01 MPaG, preferably between -0.3 MPaG and 0.01 MPaG. That is, when necessary, both heating and negative pressure methods can be used together to improve the degree of stripping of the light components.

[0056] It should be noted that when using the two methods mentioned above together, heating treatment is usually used first, followed by negative pressure treatment. This is because when the temperature is raised, a large number of light components have already been separated from the oil. After providing a negative pressure environment, the volatility of the light components in the oil can be further improved, thereby separating them from the oil more thoroughly.

[0057] Step S2, VOCs washing of oil and gas: The oil and gas to be treated is contacted with the light-oil product used as an adsorbent in step S1 to adsorb the VOCs components in the oil and gas. After absorption, a rich oil containing VOCs components and a low-concentration oil and gas with VOCs components removed are obtained. The rich oil contains the light-oil product used as an adsorbent and the heavy VOCs components adsorbed from the oil and gas to be treated. In this process, the sufficiency of adsorption can be judged by monitoring the VOCs concentration or volumetric flow rate during the adsorption process, thereby achieving the adsorption of light components in the oil and gas. The core of adsorption relies on the saturated vapor pressure control of the adsorbent itself under the corresponding operating temperature and pressure conditions. Therefore, the saturated vapor pressure of the oil can also be controlled by pressurization, cooling, etc., so that the light components in the oil and gas are better adsorbed by the adsorbent.

[0058] In some preferred embodiments, the contact between the oil and gas to be treated and the light-removed oil used as an adsorbent in step S1 can typically be a reverse contact. This reverse contact allows for sufficient contact between the oil used as an adsorbent and the oil and gas. Since the light components in the oil and gas have already been separated, there are no restrictions on the oxygen concentration in the eluted oil and gas, thus achieving complete combustion.

[0059] It should be noted that before the above-mentioned oil is pre-washed, step S2-0, oil-gas compression process, is also included, in which the oil and gas are compressed at an operating pressure between 0 MPaG and 1.0 MPaG. The light components in the compressed oil and gas are more easily adsorbed by the light oil.

[0060] Step S3, Incineration Treatment: The fuel gas obtained in step S1, the low-concentration oil and gas obtained after washing in step S2, and air are mixed in multiple stages and subjected to multi-stage combustion treatment to obtain ultra-low VOCs emission exhaust gas.

[0061] Specifically, the multi-stage mixing and multi-stage combustion process in this step includes:

[0062] Step a: Mix the fuel gas with the low-concentration oil gas and perform primary activation to obtain pre-combustion gas. In some embodiments, this primary activation is performed by: i. heating the fuel gas and low-concentration oil gas at a temperature between 50-400°C and / or, ii. catalytically activating the fuel gas and low-concentration oil gas. After the fuel gas and low-concentration oil gas are mixed, both gases can be heated. Heating intensifies the intermolecular motion of the fuel gas and low-concentration oil gas, increasing their reactivity. Furthermore, the fuel gas can be brought into contact with a catalyst during the mixing process to achieve catalytic activation. The catalyst can be, for example, a metal mesh or perforated plate made of a porous metal material composed of an alloy containing multiple materials selected from iron, chromium, aluminum, nickel, ruthenium, titanium, platinum, and rhodium. This metal mesh is placed in the device for mixing the fuel gas and low-concentration oil gas. In this case, the metal mesh can be heated or energized. When the fuel gas and low-concentration oil gas come into contact with the metal mesh, the molecules of the fuel gas and low-concentration oil gas are activated. After the above activation process, the activity of fuel gas and low-concentration oil and gas is enhanced, thus enabling more complete combustion in the subsequent process.

[0063] Step b: Mix the pre-combustion gas with air and perform primary combustion to obtain pre-emission gas. The combustion process can be carried out by external ignition to ignite the fuel gas in the pre-combustion gas and further burn low-concentration oil and gas to obtain pre-emission gas.

[0064] Step c: The pre-emission gas is mixed a second time with a low-temperature medium and then an auxiliary combustion fuel is introduced for secondary combustion to obtain ultra-low VOCs emission exhaust gas. Specifically, the pre-emission gas is ignited and rapidly combusted in step b above. After the rapid combustion reaction is completed, the pre-emission gas formed in step c is first rapidly mixed with a low-temperature medium (such as water, low-temperature air, etc.) (i.e., secondary mixing), thereby quickly removing the flame from the high-temperature zone. At the same time, an auxiliary combustion fuel is introduced and ignited for secondary combustion to obtain emission exhaust gas, thus achieving NO reduction. x The goal is to achieve ultra-low emissions simultaneously with VOCs. It should be noted that the cryogenic medium can be cryogenic gas or other cryogenic gaseous components; the purpose of the related operations is to rapidly remove the high-temperature combustible gases from the high-temperature zone. Furthermore, the combustion-supporting gas can be, for example, oxygen or ozone.

[0065] This invention employs multi-stage mixing to ensure more thorough mixing of the gases to be combusted, thereby leading to more complete combustion. Based on this, the invention utilizes multi-stage combustion. First, the pre-combustion gas undergoes initial combustion. Since heavy components that would contribute to the reaction have already been removed from the low-concentration oil and gas, low-VOC pre-emission gas is obtained during the primary combustion process. Subsequently, the pre-emission gas undergoes further mixing and secondary combustion. During this mixing process, the high-temperature burnout gas rapidly exits the high-temperature zone, and after mixing with air, the gas undergoes further combustion, thereby further reducing VOCs and nitrogen oxides in the exhaust gas—achieving multiple benefits.

[0066] This invention uses washing to transfer the combustible light components from oil and gas into the oil, which acts as an adsorbent. This increases the purity of the remaining heavy combustible components, allowing for complete combustion without producing harmful substances. Furthermore, as described above, the light components separated after stripping can be used as fuel gas in the combustion process of step S3. This eliminates the need to introduce other fuel gases, such as natural gas, from the outside, saving energy and costs while improving safety and stability.

[0067] Based on the method of this invention, conventional oil and gas processing in the prior art requires external fuel supply. This necessitates the special use of external fuel and the construction of additional fuel supply pipelines when changing locations. However, this invention, through process technology and the characteristics of the medium itself, uses the separated light components as fuel gas, achieving self-production of fuel gas and thus avoiding the need for external fuel gas supply. This makes the entire method more convenient and eliminates the need for special control of oxygen concentration. No external fuel storage facilities are required, nor are any separate pipelines needed. Therefore, the method of this invention is suitable for any location, such as storage depots, docks, etc.

[0068] In some embodiments of the present invention, before step S3 described above, step S3-0 may be included, which controls the flow rates of low-concentration oil gas and fuel gas so that the concentration of low-concentration oil gas before combustion reaches 10~600 g / m³. 3 By controlling the concentration of low-concentration oil and gas, the combustion efficiency of low-concentration oil and gas can be improved, thus eliminating the need to control the oxygen concentration and making combustion more complete.

[0069] Furthermore, in some embodiments, the method of the present invention further includes step S4, condensing and collecting the rich oil from step S2 and returning it to step S1 for further stripping. The condensation operation temperature is between -100°C and 30°C, which can prevent the oil from evaporating. The light-removed oil, acting as an adsorbent, becomes rich oil after adsorbing the light components in the oil gas. Thus, after returning the rich oil to step S1, its composition is essentially the same as the oil containing light components used in the initial step S1. Re-stripping it allows the light components to be separated again, and the light components adsorbed by the oil can be reused as fuel gas.

[0070] In this way, the oil can be recycled without adding new oil. Introducing new oil may generate excess VOCs during storage, transportation, and use. However, the method provided by this invention ensures that the oil is used within specially prepared pipelines, preventing the release of its light-element gases. This recycling not only reduces costs but also saves energy.

[0071] Optionally, in another embodiment of the present invention, because the stripping process in step S1 is relatively fast, a small amount of heavy component droplets may be mixed in during the stripping of the light component from the heavy component. This may lead to incomplete combustion in the subsequent process and waste of the entrained heavy component. Therefore, in this other embodiment, step S1 further includes a gas-liquid separation step of the light component: the light component stripped in step S1 is subjected to gas-liquid separation, the separated liquid (separated liquid) is stored, and the separated gas is used as fuel gas in the subsequent step S3 (the specific process is detailed below). The gas-liquid separation method of the present invention includes, but is not limited to, gravity sedimentation, baffle separation, centrifugal separation, wire mesh separation, ultrafiltration separation, and packing separation, etc., and can be carried out using a gas-liquid separator. The separated gas is a pure light component containing at least one of C1, C2, and C3, while the separated liquid is oil droplets mixed in with the light component. After separation, the oil (separated liquid) can be recycled to the oil tank area and then sold or used for other purposes.

[0072] Furthermore, when step S1 includes a gas-liquid separation step, the light component gas after gas-liquid separation is used as fuel gas.

[0073] Furthermore, in some embodiments of the present invention, since the fuel gas production is high, step S1 of the present invention may further include: feeding the obtained fuel gas into a buffer device for buffering. Using a buffer device for buffering can achieve the following: (1) when the fuel gas consumption of the downstream combustion device is low, the buffer device stores the fuel gas; (2) when the fuel gas consumption of the downstream combustion device is high, the buffer device releases the fuel gas; (3) when the downstream combustion device stops operating, the fuel gas enters the fuel gas pipeline network; (4) when S1 stops stripping, the gas in the fuel gas pipeline network enters the buffer device.

[0074] Furthermore, in some embodiments of the present invention, in step c above, mixing with a cryogenic medium can, for example, involve collecting the pre-emission gas and sending it into a heat exchanger or direct cooling device, thereby removing or dispersing heat from the exhaust gas. This reduces VOCs and nitrogen oxides, further lowering the flue gas temperature and achieving cryogenic flue gas emission. The cryogenic medium can be, for example, air, nitrogen, CO2, or water.

[0075] The method for controlling ultra-low VOC emissions from oil and gas in this invention utilizes the absorption effect of the oil itself and the presence of light components, enabling the use of these light components as blending fuel in subsequent combustion processes. The uneven distribution of combustibles in oil and gas leads to instability during combustion. By transferring the combustibles from the oil and gas into the oil, further volatilization produces pure fuel, thereby achieving stable combustion. No external fuel supply is required, thus solving the problem of unstable fuel availability at some project sites.

[0076] Furthermore, the present invention employs multi-stage mixing, which increases the activity of fuel gas and low-concentration oil and gas, making it more conducive to complete combustion in the later stages. On this basis, multi-stage combustion further enhances the combustion of fuel gas and low-concentration oil and gas, fundamentally reducing the content of VOCs and nitrogen oxides in exhaust gas.

[0077] The method of the present invention will be verified through the following examples: Example

[0078] A method for controlling ultra-low VOC emissions from oil products containing light components including at least one of C1, C2, and C3, comprising the following steps: Step S1, light component stripping of the oil: heating the oil to 180°C, then subjecting the oil to a negative pressure of -0.3 MPaG, thereby stripping the light components from the oil; the stripped light components are fed into a buffer device for buffering and subsequently used as fuel gas; the stripped oil is used as an adsorbent; Step S2, VOCs elution of the oil: contacting the oil to be treated with the adsorbent from step S1 to adsorb the VOCs. The process involves: 1) Absorbing VOCs components from the oil and gas to be treated, obtaining a VOC-rich oil and a low-concentration oil and gas with the VOCs components removed; 2) Incineration treatment: Step a) Mixing the fuel gas with the low-concentration oil and gas and heating it to 250°C for primary activation to obtain pre-combustion gas; Step b) Performing primary combustion on the pre-combustion gas to obtain pre-emission gas; Step c) Mixing the pre-emission gas with a low-temperature medium for secondary combustion to obtain ultra-low VOCs emission tail gas; 3) Condensing the rich oil from step S2 at 0°C, collecting it, and returning it to step S1 for further stripping and subsequent use.

[0079] Example 2

[0080] A method for controlling ultra-low VOC emissions from oil and gas products, which differs from Example 1, involves setting a porous metal mesh material containing iron, chromium, aluminum, and ruthenium in step a, and heating the metal mesh to activate the fuel gas and low-concentration oil and gas, thereby obtaining pre-combustion gas. Example

[0081] A method for controlling ultra-low VOC emissions from oil products, which differs from Example 1 in that the oil and gas are compressed before step S2, with an operating pressure of 1 MPaG.

[0082] Example 4

[0083] A method for controlling ultra-low VOC emissions from oil and gas products, differing from Example 1, involves controlling the flow rates of low-concentration oil and gas and fuel gas before step S3, ensuring that the concentrations of both are approximately 300 g / m³. 3 .

[0084] Experimental Example

[0085] The VOCs and nitrogen oxides contents in the exhaust gases of Examples 1 to 3 were tested, and the test results are shown in Table 1 below.

[0086] Table 1 Results of VOCs and nitrogen oxide content in exhaust gases from Examples 1 to 3

[0087]

[0088] As can be seen from the results in the table above, the method for controlling ultra-low VOCs emissions from oil and gas using the present invention results in extremely low VOCs and nitrogen oxide content in the exhaust gas, far below the emission standards, allowing for direct emission.

[0089] According to a second aspect of the present invention, a system for controlling ultra-low emissions of VOCs from oil products and oil vapors is provided, such as... Figure 1 As shown, the control system includes: a fuel gas production unit 1, an oil and gas washing unit 2, and a combustion unit 3.

[0090] The fuel gas production unit 1 includes a first gas-liquid separator 12, which has an oil inlet 11 and further includes an upper outlet 121 and a lower outlet 122. The first gas-liquid separator 12 is used to remove light components from the oil. The oil to be processed enters the first gas-liquid separator 12 through the oil inlet 11. In some embodiments, the first gas-liquid separator 12 may be equipped with a heating device 123 and / or a vacuum generator 124. In this case, the oil entering the first gas-liquid separator 12 is heated by the heating device 123 and / or flashed by the vacuum generator 124, thereby removing the light components from the oil.

[0091] When the first gas-liquid separator 12 is equipped with both a heating device 123 and a vacuum generator 124, the heating device is usually located upstream to heat the oil first, and then a vacuum is provided. This can improve the volatility of the light components in the oil and facilitate the more complete stripping of the light components.

[0092] At this time, the first gas-liquid separation device 12 contains light components in a gaseous state and oil in a liquid state. The oil in the liquid state is discharged from the lower outlet 122 as an adsorbent for subsequent use, and the light components in the gaseous state are discharged from the upper outlet 121 as fuel gas for subsequent use.

[0093] Furthermore, the oil and gas scrubbing unit 2 includes a scrubbing tower 21, such as... Figure 1As shown, the scrubbing tower 21 can be, for example, a plate tower or a packed tower, and the present invention does not impose any particular limitation on it. The scrubbing tower 21 has a first oil and gas inlet 211 at the bottom, an adsorbent inlet 212 at the top, a low-concentration oil and gas outlet 213 at the top, and a rich oil outlet 214 at the bottom. The adsorbent inlet 212 is connected to the lower outlet 122 of the first gas-liquid separator 12 via a pipeline. Oil and gas enter the scrubbing tower 21 through the first oil and gas inlet 211 at the bottom, while the oil, stripped of light components, acts as the adsorbent and enters the scrubbing tower 21 through the adsorbent inlet 212 at the top. This counter-current contact between the two significantly increases their contact area, allowing the adsorbent to better adsorb the light components in the oil and gas.

[0094] Furthermore, the washed oil and gas are discharged from the low-concentration oil and gas outlet 213 at the top of the tower, while the rich oil, which has adsorbed light components from the oil and gas, is discharged from the rich oil outlet 214 at the bottom of the tower. In some embodiments, the rich oil outlet 214 at the bottom of the tower can be connected to the oil inlet 11 via a pipeline, thereby allowing the rich oil, which has adsorbed light components from the oil and gas, to be discharged back into the fuel gas production unit 1 for further light component stripping, followed by continued oil and gas washing. This can greatly save on oil usage. It should be noted that after a certain cycle, new oil can be added from the oil inlet, and a portion of the rich oil can be discharged and centrally processed. This ensures that the light components in the oil and gas are fully adsorbed during subsequent washing processes.

[0095] Optionally, the oil and gas scrubbing unit 2 may also include a compression device 4 (not shown in the figure), which is located at the front end of the oil and gas inlet of the scrubbing tower 21 and is used to compress the oil and gas.

[0096] Furthermore, the combustion unit 3 includes a gas mixing device 31 and a combustion device 32. The gas mixing device 31 is used to mix fuel gas with low-concentration oil gas and perform primary activation. The gas mixing device 31 includes a fuel gas inlet 311, a low-concentration oil gas inlet 312 connected to the low-concentration oil gas outlet 213, and a pre-combustion gas outlet 313. The fuel gas inlet 311 of the gas mixing device 31 is connected to the upper outlet 121 of the first gas-liquid separator 12. The light components discharged from the upper outlet 121 of the first gas-liquid separator 12 enter the gas mixing device 31 as fuel gas through the fuel gas inlet 311. The washed oil gas, having removed its internal light components, enters the gas mixing device 31 through the low-concentration oil gas inlet 312.

[0097] Optionally, the gas mixing device 31 may be equipped with a heating device and / or a metal mesh or perforated plate made of a porous metal material composed of an alloy of various materials including iron, chromium, aluminum, nickel, ruthenium, titanium, platinum, and rhodium, thereby enabling primary activation of fuel gas and low-concentration oil and gas.

[0098] The combustion device 32 includes a pre-combustion gas inlet 321 connected to the pre-combustion gas outlet 313, an auxiliary combustion gas inlet 325, an ignition port 322, a cryogenic medium inlet 323, and an exhaust gas outlet 324. The pre-combustion gas, after being discharged from the pre-combustion gas outlet 313 of the gas mixing device 31, enters the combustion device through the pre-combustion gas inlet 321. At this point, it is ignited through the ignition port 322, rapidly burning the pre-combustion gas to obtain pre-exhaust gas. Once the pre-exhaust gas is generated, the cryogenic medium inlet 323 is opened, introducing a cryogenic medium into the combustion device, thereby quickly removing the flame generated by rapid combustion from the high-temperature zone. Simultaneously, the auxiliary combustion gas inlet 325 is opened. A blower can be installed at the auxiliary combustion gas inlet 325 to blow auxiliary combustion gas into the combustion device, further mixing the auxiliary combustion gas with the pre-exhaust gas. Then, the ignition port 322 is activated again for secondary combustion, obtaining exhaust gas, which is discharged through the exhaust gas outlet 324.

[0099] It should be noted that the combustion device 32 used in this invention can be, for example, a high-efficiency combustion device, such as a regenerative incinerator.

[0100] Furthermore, to control the oil and gas flow rate, a flow control valve 5 is installed on the pipeline between the low-concentration oil and gas outlet 213 and the low-concentration oil and gas inlet 312. The flow control valve 5 is used to control the concentration of oil and gas entering the gas mixing device 31 (and subsequently the combustion device 32), ensuring that its concentration is between 10 and 600 g / m³. 3 Preferred concentration: 30~400g / m 3 .

[0101] Furthermore, in a second embodiment of the system of the present invention, see... Figure 2When it is necessary to separate the light components from the oil and use them as fuel gas in the subsequent combustion process, the fuel gas inlet 311 of the gas mixing device 31 needs to be connected to the upper outlet 121 of the first gas-liquid separator 12. In this case, the gaseous light components may carry some liquid when they are discharged from the upper outlet 121 of the first gas-liquid separator 12. To avoid incomplete combustion in subsequent use, the fuel gas production unit 1 of the present invention also includes a second gas-liquid separator 13. The second gas-liquid separator 13 is disposed between the upper outlet 121 of the first gas-liquid separator 12 and the fuel gas inlet 311. The upper end of the second gas-liquid separator has a fuel gas outlet 131 connected to the fuel gas inlet 311, and the lower end of the second gas-liquid separator 13 has a separated liquid outlet 132. The gaseous light components separated in the second gas-liquid separator 13 enter the combustion device 32 through the fuel gas inlet 311. The separated liquid is the oil entrained in the light components. Since the separation is thorough, it can be resold as a commodity. The second gas-liquid separation device can be, for example, a separator, which can perform gas-liquid separation by means of gravity sedimentation, baffle separation, centrifugal force separation, wire mesh separation, ultrafiltration separation, packing separation, etc. The present invention does not particularly limit this.

[0102] Furthermore, in order to better control the subsequent use of fuel gas, the burner production unit 1 of the system of the present invention may also include a buffer device (not shown in the figure), which is disposed between the fuel gas outlet 131 and the fuel gas inlet 311 of the second gas-liquid separator 13. The buffer device may be, for example, a pressure relief gas storage tank, a pulse gas storage tank, a constant pressure gas storage tank, etc. Using the buffer device for buffering can achieve the following: (1) when the fuel gas consumption of the downstream combustion device is low, the buffer device stores fuel gas; (2) when the fuel gas consumption of the downstream combustion device is high, the buffer device releases fuel gas; (3) when the downstream combustion device stops running, the fuel gas enters the fuel gas pipeline; (4) when the stripping of S1 stops, the gas in the fuel gas pipeline enters the buffer device.

[0103] Furthermore, according to a third embodiment of the system of the present invention, see... Figure 3 , attached Figure 3 A system with a condenser 6 for controlling ultra-low VOC emissions from oil products and oil vapors is shown. Figure 3 The second gas-liquid separator is not shown in the diagram, but in actual use, the operator can connect the aforementioned second gas-liquid separator as needed (see [link to diagram] for details). Figure 2 ).

[0104] In some embodiments of the present invention, a condensing device 6 is provided outside the rich oil outlet 214. The outlet of the condensing device 6 is connected to the oil inlet 11 via a pipe, and a reflux pump 7 is provided on the pipe between the rich oil outlet 214 and the oil inlet 11. The rich oil that has adsorbed light components in the oil-gas washing unit 2 is discharged from the rich oil outlet 214 and can be refluxed back to the oil inlet 11 to discharge the light components from the oil again. At this time, the temperature of the oil is raised in the oil-gas washing unit 2, so its volatilization is prevented, and thus the condensing device 6 is used to reduce the volatilization of the oil.

[0105] Optionally, each inlet and outlet of the system for controlling ultra-low emissions of VOCs in oil and gas of the present invention is equipped with a solenoid valve. By controlling the opening and closing of the solenoid valve, the opening and closing of the inlet and outlet can be controlled. For example, during the operation of the scrubbing tower, when oil and gas and adsorbent are introduced into the scrubbing tower, the solenoid valves of the oil and gas inlet and the adsorbent inlet are opened, and the oil and gas are scrubbed. After the scrubbing is completed, the solenoid valves of the oil and gas inlet and the adsorbent inlet are closed, and the solenoid valves of the low-concentration oil and gas outlet and the rich oil outlet are opened, thereby discharging the low-concentration oil and gas and the rich oil. The present invention does not specifically describe similar working processes, and those skilled in the art can set them up using common knowledge.

[0106] Therefore, the system provided by this invention separates light components from oil products through a fuel gas production unit for use as fuel reserves. Simultaneously, the absorption efficiency of the oil after extracting light components is significantly improved, allowing it to be used as an adsorbent in an oil-gas scrubbing unit. The adsorbent can be recycled. After scrubbing, the uniformity of oil-gas concentration is improved, avoiding the impact of large fluctuations in oil-gas concentration on the combustion device. Furthermore, the system provided by this invention is easy to install and can be directly assembled onto existing equipment in different scenarios.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A method for controlling ultra-low VOC emissions from oil products, wherein the oil products originate from the volatilization of the oil products during storage and transportation, and wherein the oil products contain light components comprising at least one of C1, C2, and C3, characterized in that... The method includes the following steps: Step S1, Light component stripping of oil: The light components in the oil are stripped off, the stripped light components are used as fuel gas, and the oil after stripping the light components is used as an adsorbent. Step S2, VOCs elution of oil and gas: The oil and gas to be treated is contacted with the adsorbent in step S1 to adsorb the VOCs components in the oil and gas to be treated. After absorption, a rich oil containing VOCs components and a low-concentration oil and gas with the VOCs components removed are obtained. Step S3, Incineration Treatment: The fuel gas obtained in Step S1, the low-concentration oil and gas obtained in Step S2, and air are mixed in multiple stages and subjected to multi-stage combustion treatment to obtain ultra-low VOCs emission exhaust gas. The multi-stage mixing and multi-stage combustion process in step S3 includes: Step a: Mix the fuel gas with the low-concentration oil and gas and perform primary activation to obtain pre-combustion gas; Step b: Mix the pre-combustion gas with air and then perform primary combustion to obtain pre-emission gas; and Step c: The pre-emission gas is mixed with a cryogenic medium for a second time and then introduced with combustion-supporting gas for secondary combustion, thereby obtaining ultra-low VOCs emission exhaust gas, wherein... The primary activation in step a is performed by the following method: The fuel gas and the low-concentration oil gas are heated to a temperature between 50-400°C; and / or The fuel gas and the low-concentration oil and gas are catalytically activated.

2. The method for controlling ultra-low emissions of VOCs in oil and oil gas according to claim 1, characterized in that, The light component stripping in step S1 is performed using at least one of the following methods: (1) Heating, controlling the separation operation temperature between 120℃ and 200℃; (2) Negative pressure: The separation operation pressure is controlled between -1.0 MPaG and -0.3 MPaG, and Step S1 further includes: The obtained fuel gas is fed into a buffer device for caching.

3. The method for controlling ultra-low emissions of VOCs in oil and oil gas according to claim 1, characterized in that, Before step S2, the method further includes: step S2-0, oil-gas compression: compressing the oil-gas to be processed at an operating pressure between 0 MPaG and 2.0 MPaG; and / or Before step S3, the method further includes step S3-0, which controls the flow rates of the low-concentration oil gas and the fuel gas, such that the concentrations of both the low-concentration oil gas and the fuel gas are between 10 and 600 g / m³. 3 between.

4. The method for controlling ultra-low emissions of VOCs in oil and oil gas according to claim 1, characterized in that, The method further includes step S4, condensing and collecting the rich oil from step S2 and returning it to step S1 for stripping and subsequent use, wherein the condensation operation temperature is between -100℃ and 30℃.

5. A system for implementing the method for controlling ultra-low emissions of VOCs in oil products according to any one of claims 1 to 4, wherein the oil products originate from the volatilization of the oil products during the oil product storage and transportation process, and wherein the oil products contain light components comprising at least one of C1, C2, and C3, characterized in that, The system includes: A fuel gas production unit includes a first gas-liquid separator, which has an oil inlet and an upper outlet and a lower outlet. Oil and gas scrubbing unit, comprising: A scrubbing tower is provided with a first oil and gas inlet at the lower part of the tower body, through which the oil and gas enter the scrubbing tower. An adsorbent inlet is provided at the upper part of the tower body, a low-concentration oil and gas outlet is provided at the top of the tower, and a rich oil outlet is provided at the bottom of the tower. The adsorbent inlet is connected to the lower outlet of the first gas-liquid separation device through a pipeline. Combustion unit, comprising: A gas mixing device, the gas mixing device including a fuel gas inlet and a low-concentration oil and gas inlet connected to the low-concentration oil and gas outlet, and a pre-combustion gas outlet, wherein the fuel gas inlet of the gas mixing device is connected to the upper outlet of the first gas-liquid separator; The combustion device includes a pre-combustion gas inlet, an air inlet, an ignition port, a cryogenic medium inlet, and a pre-discharge gas outlet, wherein the pre-combustion gas inlet and the pre-combustion gas outlet are connected.

6. The system according to claim 5, characterized in that, The fuel gas production unit also includes: A second gas-liquid separator is disposed between the upper outlet of the first gas-liquid separator and the fuel gas inlet. The upper end of the second gas-liquid separator has a fuel gas outlet communicating with the fuel gas inlet, and the lower end of the second gas-liquid separator has a separated liquid outlet. A buffer device is provided, which is disposed between the fuel gas outlet and the fuel gas inlet of the second gas-liquid separator. The first gas-liquid separation device includes a heating device and / or a vacuum generating device.

7. The system according to claim 5 or 6, characterized in that, The oil and gas scrubbing unit further includes a compression device, which is located at the upstream end of the oil and gas inlet of the scrubbing tower; and / or A flow control valve is installed on the pipeline between the low-concentration oil and gas outlet and the low-concentration oil and gas inlet.

8. The system according to claim 5 or 6, characterized in that, A condensing device is provided outside the rich oil outlet. The outlet of the condensing device is connected to the oil inlet through a pipeline. A reflux pump is provided on the pipeline between the lower outlet and the oil inlet.

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