Tail gas treatment system and treatment method for modified asphalt device in refinery plant

Abstract

The invention provides a tail gas treatment system in modified asphalt production. The tail gas treatment system comprises a tail gas collection unit; the cooling liquid collecting tower is connected with the tail gas collecting unit; the solvent absorption tower is connected with the cooling liquid collection tower; the alkali liquor absorption tower is connected with the solvent absorption tower; and the activated carbon adsorption tower is connected with the alkali liquor absorption tower. By utilizing the unique characteristics of a modified asphalt production device in a refinery plant, the tail gas generated in the production, storage and loading sections of the modified asphalt is intensively incinerated, a large heating furnace system of an adjacent device is fully utilized, and unorganized emission of the device is avoided by transferring the tail gas and eliminating a tail gas exhaust funnel of the device; tail gas is harmlessly discharged through incineration of a heating furnace of an existing device. According to the tail gas treatment method, various pollutants such as macromolecular organic matters and sulfur-containing substances in the tail gas of the modified asphalt device can be efficiently removed, meanwhile, the treatment cost is reduced, harmless emission of the tail gas is achieved, and the environment-friendly requirement is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of modified asphalt tail gas, and relates to a tail gas treatment system and a tail gas treatment process in the production of modified asphalt, and particularly relates to a tail gas treatment system and a treatment method for a modified asphalt device in a refinery. Background Art

[0002] With the development of the petrochemical industry, the production scale of modified asphalt has been continuously expanding. During the production process of modified asphalt, a large amount of tail gas is generated from the production tank, the development tank to the loading link. These tail gases contain various harmful substances, such as macromolecular organic substances, sulfur-containing compounds, etc. If directly discharged into the atmosphere, it will cause serious harm to the surrounding environment, the health of employees and residents, such as causing a decline in air quality, the formation of acid rain, an increase in respiratory diseases, etc. At the same time, with the increasingly strict environmental protection regulations, modified asphalt manufacturers are facing great pressure in tail gas treatment and urgently need an efficient and reliable tail gas treatment technology.

[0003] Currently, some refineries adopt simple adsorption treatment methods. For example, some refineries only use activated carbon to adsorb some pollutants in the tail gas, but the removal effect on sulfur-containing substances is not good, and the activated carbon is easy to be saturated and needs to be replaced frequently, with high costs and limited treatment efficiency. There are also some refineries that adopt direct combustion methods. This method requires the construction of a new set of tail gas incinerators, which requires a large amount of land occupation and investment in the device, and the energy consumption during the combustion process is high, which is not conducive to energy conservation and emission reduction.

[0004] Therefore, how to find a more suitable tail gas treatment method for the modified asphalt device in a refinery to solve the above-mentioned tail gas treatment problems has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a tail gas treatment system and a tail gas treatment process in the production of modified asphalt, especially a tail gas treatment system and a treatment method for a modified asphalt device in a refinery. The treatment system and method provided by the present invention can efficiently remove various pollutants such as macromolecular organic substances and sulfur-containing substances in the tail gas of the modified asphalt device in the refinery while reducing the treatment cost, realizing the harmless emission of the tail gas and meeting the environmental protection requirements. Moreover, the process and device are simple, the conditions are mild, the controllability and operability are strong, and it is green and environmentally friendly, and is more suitable for industrial production promotion and application.

[0006] The present invention provides a tail gas treatment system in the production of modified asphalt, including:

[0007] A tail gas collection unit;

[0008] A cooling and liquid collection tower connected to the tail gas collection unit;

[0009] A solvent absorption tower connected to the cooling liquid collection tower;

[0010] An alkali solution absorption tower connected to the solvent absorption tower;

[0011] An activated carbon adsorption tower connected to the alkali solution absorption tower.

[0012] Preferably, the tail gas collection unit includes a draft fan conveying system;

[0013] The inlets of the draft fan conveying system are respectively connected to the flue gas pipelines generated by the modified asphalt production tank, the development tank, and the loading;

[0014] The outlet of the draft fan conveying system is connected to the inlet of the cooling liquid collection tower.

[0015] Preferably, the cooling liquid collection tower is specifically a heat exchange cooling liquid collection tower with a jacket structure;

[0016] The heat exchange pipeline of the heat exchange cooling liquid collection tower is connected to the first blower for air cooling;

[0017] The bottom of the cooling liquid collection tower is a liquid collection space;

[0018] The cooling tail gas outlet of the cooling liquid collection tower is located between the liquid collection space and the heat exchange pipeline.

[0019] Preferably, the cooling tail gas outlet of the cooling liquid collection tower is connected to the inlet of the solvent absorption tower through a first draft fan;

[0020] The inlet of the solvent absorption tower is arranged at the lower part of the solvent absorption tower;

[0021] In the solvent absorption tower, multiple layers of solvent spraying devices with different heights are arranged above the inlet;

[0022] The outlet of the solvent absorption tower is arranged at the top of the solvent absorption tower.

[0023] Preferably, the tail gas treatment system further includes a first circulation pump;

[0024] The inlet of the first circulation pump is connected to the absorption liquid outlet at the bottom of the solvent absorption tower and the solvent source;

[0025] The outlet of the first circulation pump is respectively connected to the inlets of the solvent spraying devices.

[0026] Preferably, the outlet of the solvent absorption tower is connected to the inlet of the alkali solution absorption tower;

[0027] The inlet of the alkali solution absorption tower is arranged at the lower part of the alkali solution absorption tower;

[0028] Inside the caustic solution absorption tower, a caustic solution spraying device is arranged above the inlet;

[0029] The outlet of the caustic solution absorption tower is arranged at the top of the solvent absorption tower.

[0030] Preferably, the tail gas treatment system further includes a second circulation pump;

[0031] The inlet of the second circulation pump is connected to the absorption liquid outlet at the bottom of the caustic solution absorption tower and the caustic solution source;

[0032] The outlet of the second circulation pump is connected to the inlet of the caustic solution spraying device;

[0033] The outlet of the caustic solution absorption tower is connected to the inlet of the activated carbon adsorption tower;

[0034] The tail gas treatment system further includes an incineration device;

[0035] The outlet of the activated carbon adsorption tower is connected to the inlet of the incineration device.

[0036] The present invention provides a tail gas treatment process in the production of modified asphalt, including the following steps:

[0037] 1) Collect one or more of the flue gases generated from the modified asphalt production tank, the development tank, and the loading by an induced draft fan to obtain the tail gas to be treated, and then transport it to the cooling liquid collection tower. After air-cooled heat exchange, the cooled tail gas is obtained;

[0038] 2) Feed the cooled tail gas obtained in the above step into the solvent adsorption tower, and after being sprayed with multiple layers of organic solvents from bottom to top, the tail gas after solvent adsorption is obtained;

[0039] 3) Feed the tail gas after solvent adsorption obtained in the above step into the caustic solution adsorption tower, and after being sprayed with multiple layers of alkaline solution from bottom to top, the tail gas after caustic solution adsorption is obtained;

[0040] 4) After the tail gas after caustic solution adsorption obtained in the above step is adsorbed by activated carbon, the treated tail gas is obtained.

[0041] Preferably, the tail gas to be treated includes oil components, aromatic hydrocarbon compounds, hydrogen sulfide, asphalt fume, and dust;

[0042] The aromatic hydrocarbon compounds include benzo[a]pyrene;

[0043] The temperature of the tail gas to be treated is 70 - 100 °C;

[0044] The temperature of the cooled tail gas is 40 - 60 °C;

[0045] The number of layers of the multiple layers is 2 - 5 layers;

[0046] The organic solvent includes one or more of diesel, n-hexane, and xylene.

[0047] Preferably, the alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution;

[0048] The modified asphalt is specifically SBS series modified asphalt and / or high durability high modulus asphalt;

[0049] In the treated tail gas, SO2 ≤ 50 mg / m 3 ;

[0050] In the treated tail gas, dust ≤ 10 mg / m 3 ;

[0051] In the treated tail gas, nitrogen oxides ≤ 100 mg / m 3 ;

[0052] The treated tail gas further includes a step of incineration treatment.

[0053] The present invention provides a tail gas treatment system in the production of modified asphalt, including: a tail gas collection unit; a cooling and liquid collection tower connected to the tail gas collection unit; a solvent absorption tower connected to the cooling and liquid collection tower; an alkali solution absorption tower connected to the solvent absorption tower; and an activated carbon adsorption tower connected to the alkali solution absorption tower. Compared with the prior art, for the existing tail gas treatment of modified asphalt, there are problems such as the adsorption technology cannot comprehensively remove various pollutants such as macromolecular organic matters and sulfur-containing substances in the tail gas, resulting in incomplete tail gas treatment and low treatment efficiency; while in the direct combustion method, there is a need to newly build a set of tail gas incinerators, which requires a large floor area and investment in the device, and the energy consumption during the combustion process is relatively high, which is not conducive to energy conservation and emission reduction and has high costs. The present invention particularly utilizes the unique advantages of the modified asphalt production device in the refinery, and incinerates the currently difficult-to-treat modified asphalt tail gas by collecting and transporting it to the existing heating furnace in the refinery, with small investment and remarkable effects.

[0054] The present invention creatively designs a tail gas treatment system in the production of modified asphalt with a specific structure and composition. It mainly utilizes the unique characteristics of the modified asphalt production device in the refinery to centrally incinerate the tail gas generated during the production, storage, and loading of modified asphalt, fully utilizes the large heating furnace system of the adjacent device, eliminates the tail gas exhaust stack of the device through tail gas transfer, avoids the fugitive emission of the device, and makes the tail gas undergo harmless emission through the incineration of the existing device heating furnace. The tail gas treatment system provided by the present invention can efficiently remove various pollutants such as macromolecular organic matters and sulfur-containing substances in the tail gas of the modified asphalt device while reducing the treatment cost, realizing the harmless emission of the tail gas and meeting the environmental protection requirements.

[0055] The present invention adopts a treatment method combining multiple adsorption and incineration. Compared with single adsorption or combustion technologies, it can remove various pollutants such as macromolecular organic compounds and sulfur-containing substances in the tail gas more comprehensively and efficiently. Through multi-step treatments such as cooling and liquid collection, solvent adsorption, alkali solution adsorption, and activated carbon adsorption, the purification degree of the tail gas is greatly improved, and the treated tail gas can meet more stringent environmental protection emission standards. Moreover, during the alkali solution adsorption process, by precisely controlling the composition, concentration, and flow rate of the alkali solution, sulfur-containing substances can be targeted for removal, reducing the risk of secondary pollution caused by incomplete combustion of sulfur-containing substances. At the same time, the reasonable application of solvent adsorption and activated carbon adsorption further reduces pollutant emissions and avoids the generation of harmful gases such as dioxins.

[0056] The present invention also provides a corresponding multi-step treatment process. By reasonably designing the process flow and equipment selection, such as the coordinated operation of the tail gas relay fan and the induced draft fan of the large device heating furnace, and the recycling of the coolant in the cooling and liquid collection tower, the overall treatment cost is reduced. Compared with the traditional treatment methods of frequently replacing activated carbon adsorption or high-energy-consuming combustion, it has better economy in long-term operation.

[0057] The tail gas treatment system and its tail gas treatment process in the production of modified asphalt provided by the present invention aim to be an efficient, comprehensive, and environmentally friendly method for treating tail gas in a modified asphalt device in a refinery. It solves the existing problems in tail gas treatment, realizes the harmless emission of tail gas, reduces environmental pollution, and meets the requirements of relevant environmental protection standards.

[0058] The actual application results show that by using the treatment system and method of the present invention, after continuous detection, the tail gas indexes in the tail gas are: SO2 ≤ 50 mg / m 3 , dust ≤ 10 mg / m 3 , nitrogen oxides 100 mg / m 3 ; far lower than the limits of relevant environmental protection standards.

[0059] Compared with the newly built incinerator: RTO regenerative thermal oxidizer: Generally, the equipment price of an RTO regenerative thermal oxidizer for treating 10,000 m 3 / h is about 300,000 yuan, and the installation cost may range from 100,000 to 200,000 yuan; the annual operating cost: the annual fuel cost for energy consumption is about 1.2 million yuan, and the electricity cost is about 40,000 yuan per year. The present invention can save about 500,000 yuan in the cost of building a new incinerator and about 1.25 million yuan in energy consumption cost per year. Brief Description of the Drawings

[0060] Figure 1 It is the process flow diagram of the tail gas treatment system in the production of modified asphalt provided by the present invention. Detailed Embodiments

[0061] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0062] For all raw materials of the present invention, there are no special restrictions on their sources, and they can be purchased on the market or prepared according to conventional methods well-known to those skilled in the art.

[0063] For the raw materials used in the present invention, there are no special restrictions on their purity. The present invention preferably adopts industrial purity or the purity conventional in the field of modified asphalt tail gas treatment.

[0064] All the noun expressions and abbreviations in the present invention belong to the conventional noun expressions and abbreviations in the field. Each noun expression and abbreviation is clear and definite in its relevant application field, and those skilled in the art can clearly, accurately and uniquely understand them according to the noun expressions and abbreviations.

[0065] The present invention provides a tail gas treatment system in the production of modified asphalt, including:

[0066] A tail gas collection unit;

[0067] A cooling liquid collection tower connected to the tail gas collection unit;

[0068] A solvent absorption tower connected to the cooling liquid collection tower;

[0069] An alkali solution absorption tower connected to the solvent absorption tower;

[0070] An activated carbon adsorption tower connected to the alkali solution absorption tower.

[0071] In the present invention, the tail gas collection unit preferably includes a draft fan conveying system.

[0072] In the present invention, the inlets of the draft fan conveying system are preferably respectively connected to the flue gas pipelines generated by the modified asphalt production tank, the development tank, and the loading.

[0073] In the present invention, the outlet of the draft fan conveying system is preferably connected to the inlet of the cooling liquid collection tower.

[0074] In the present invention, the cooling liquid collection tower is specifically preferably a heat exchange cooling liquid collection tower with a jacket structure.

[0075] In the present invention, the heat exchange pipeline of the heat exchange cooling liquid collection tower is preferably connected to a first blower for air cooling.

[0076] In the present invention, the bottom of the cooling liquid collection tower is preferably a liquid collection space.

[0077] In the present invention, the cooling tail gas outlet of the cooling liquid collecting tower is preferably located between the liquid collecting space and the heat exchange pipeline.

[0078] In the present invention, the cooling tail gas outlet of the cooling liquid collecting tower is preferably connected to the inlet of the solvent absorption tower through a first induced draft fan.

[0079] In the present invention, the inlet of the solvent absorption tower is preferably arranged at the lower part of the solvent absorption tower.

[0080] In the present invention, inside the solvent absorption tower, a plurality of solvent spraying devices with different heights are preferably arranged above the inlet.

[0081] In the present invention, the outlet of the solvent absorption tower is preferably arranged at the top of the solvent absorption tower.

[0082] In the present invention, the tail gas treatment system preferably further includes a first circulation pump.

[0083] In the present invention, the inlet of the first circulation pump is preferably connected to the absorption liquid outlet at the bottom of the solvent absorption tower and a solvent source.

[0084] In the present invention, the outlet of the first circulation pump is preferably connected to the inlets of the solvent spraying devices respectively.

[0085] In the present invention, the outlet of the solvent absorption tower is preferably connected to the inlet of the alkali solution absorption tower.

[0086] In the present invention, the inlet of the alkali solution absorption tower is preferably arranged at the lower part of the alkali solution absorption tower.

[0087] In the present invention, inside the alkali solution absorption tower, an alkali solution spraying device is preferably arranged above the inlet. Specifically, the alkali solution spraying device preferably includes a plurality of alkali solution spraying devices with different heights.

[0088] In the present invention, the outlet of the alkali solution absorption tower is preferably arranged at the top of the solvent absorption tower.

[0089] In the present invention, the tail gas treatment system preferably further includes a second circulation pump.

[0090] In the present invention, the inlet of the second circulation pump is preferably connected to the absorption liquid outlet at the bottom of the alkali solution absorption tower and an alkali solution source.

[0091] In the present invention, the outlet of the second circulation pump is connected to the inlet of the alkali solution spraying device;

[0092] In the present invention, the outlet of the alkali solution absorption tower is preferably connected to the inlet of the activated carbon adsorption tower.

[0093] In the present invention, the tail gas treatment system preferably further includes an incinerator.

[0094] In the present invention, the outlet of the activated carbon adsorption tower is preferably connected to the inlet of the incinerator.

[0095] The present invention provides a tail gas treatment process in the production of modified asphalt, comprising the following steps:

[0096] 1) One or more of the flue gases generated from the modified asphalt production tank, the development tank, and the loading are collected by a draft fan to obtain the tail gas to be treated, which is then transported to a cooling and liquid collection tower. After air-cooled heat exchange, the cooled tail gas is obtained.

[0097] 2) The cooled tail gas obtained in the above step is fed into a solvent adsorption tower and is sprayed with multiple layers of organic solvents from bottom to top to obtain the tail gas after solvent adsorption.

[0098] 3) The tail gas after solvent adsorption obtained in the above step is fed into an alkaline solution adsorption tower and is sprayed with an alkaline solution from bottom to top to obtain the tail gas after alkaline solution adsorption.

[0099] 4) The tail gas after alkaline solution adsorption obtained in the above step is adsorbed by activated carbon to obtain the treated tail gas.

[0100] In the present invention, first, one or more of the flue gases generated from the modified asphalt production tank, the development tank, and the loading are collected by a draft fan to obtain the tail gas to be treated, which is then transported to a cooling and liquid collection tower. After air-cooled heat exchange, the cooled tail gas is obtained.

[0101] In the present invention, the tail gas to be treated preferably includes oil components, aromatic hydrocarbon compounds, hydrogen sulfide, asphalt fume, and dust.

[0102] In the present invention, the aromatic hydrocarbon compounds preferably include benzo[a]pyrene.

[0103] In the present invention, the temperature of the tail gas to be treated is preferably 70 - 100 °C, more preferably 75 - 95 °C, and even more preferably 80 - 90 °C.

[0104] In the present invention, the temperature of the cooled tail gas is preferably 40 - 60 °C, more preferably 42 - 58 °C, even more preferably 45 - 55 °C, and even more preferably 47 - 52 °C.

[0105] In the present invention, then the cooled tail gas obtained in the above step is fed into a solvent adsorption tower and is sprayed with multiple layers of organic solvents from bottom to top to obtain the tail gas after solvent adsorption.

[0106] In the present invention, the number of layers of the multiple layers is preferably 2 - 5 layers, more preferably 2 - 4 layers or 3 - 4 layers. Specifically, the trays of the solvent tower can be 3 layers, and the trays of the alkaline solution tower can be 2 layers.

[0107] In the present invention, the organic solvent preferably includes one or more of diesel oil, n-hexane, and xylene. More preferably, it is diesel oil, n-hexane, or xylene.

[0108] The present invention then sends the tail gas adsorbed by the solvent obtained in the above steps into an alkaline solution absorption tower. After passing through the alkaline solution spray from bottom to top, the tail gas after alkaline solution absorption is obtained.

[0109] In the present invention, the alkaline solution preferably includes sodium hydroxide solution and / or potassium hydroxide solution. More preferably, it is sodium hydroxide solution or potassium hydroxide solution.

[0110] In the present invention, in the treated tail gas, preferably SO2 ≤ 50 mg / m 3 ; dust 10 mg / m 3 , nitrogen oxides 100 mg / m 3 Inside, more preferably SO2 ≤ 40 mg / m 3 , more preferably SO2 ≤ 30 mg / m 3 .

[0111] In the present invention, in the treated tail gas, preferably dust ≤ 10 mg / m 3 , more preferably ≤ 9 mg / m 3 , more preferably ≤ 8 mg / m 3 .

[0112] In the treated tail gas, preferably nitrogen oxides ≤ 100 mg / m 3 , more preferably ≤ 90 mg / m 3 , more preferably ≤ 80 mg / m 3 .

[0113] The present invention finally passes the tail gas after alkaline solution absorption obtained in the above steps through activated carbon adsorption to obtain the treated tail gas.

[0114] The treated tail gas also preferably includes a step of incineration treatment.

[0115] In order to complete and refine the overall technical solution of the present invention, better ensure the stability and efficiency of the tail gas treatment system in the production of modified asphalt, and further improve the treatment effect of the tail gas treatment system in the production of modified asphalt, the tail gas treatment system and treatment method of the modified asphalt device in the above refinery can specifically include the following content:

[0116] The tail gas treatment system in the production of modified asphalt provided by the present invention includes:

[0117] Tail gas collection unit: The flue gas generated from the modified asphalt production tank, development tank, and loading is first collected by an induced draft fan to ensure stable conveyance of the tail gas to the subsequent treatment unit.

[0118] Cooling and liquid collection unit: The collected tail gas enters the cooling and liquid collection tower. The cooling and liquid collection tower adopts a jacket structure and uses a blower for air cooling. Through heat exchange, some condensable substances in the tail gas are condensed into liquids and collected. This part of the coolant can be further processed.

[0119] Solvent adsorption unit: The cooled tail gas enters the solvent adsorption tower. In the solvent adsorption tower, specific organic solvents are used to adsorb and remove the macromolecular organic substances in the tail gas. The selection of the solvent should be based on its affinity for macromolecular organic substances and recyclability. During the adsorption process, the tail gas is in full contact with the solvent, and through physical adsorption, the macromolecular organic substances adhere to the surface of the solvent.

[0120] Alkali solution adsorption unit: The tail gas after solvent adsorption enters the alkali solution adsorption tower. The alkali solution adsorption tower is filled with an alkaline solution such as sodium hydroxide solution. Sulfur-containing substances undergo chemical reactions in the alkali solution to form corresponding sulfide precipitates or other harmless substances, thereby removing the sulfur-containing components in the tail gas. The concentration and flow rate of the alkali solution are adjusted according to the sulfur content in the tail gas to ensure good adsorption effects.

[0121] Activated carbon adsorption unit: The tail gas after alkali solution adsorption then enters the activated carbon adsorption tower for further adsorption treatment. Activated carbon has a rich pore structure and can adsorb residual small molecular organic substances, odor substances, etc. in the tail gas.

[0122] Tail gas conveyance and incineration unit: The tail gas after the above series of adsorption treatments is pumped into the suction tower of the induced draft fan of the existing device's heating furnace through a tail gas relay fan, and then inhaled into the heating furnace by the induced draft fan of the existing device for incineration treatment.

[0123] During the incineration process, by controlling the flue gas emission index (flue gas detection hut) of the existing device's heating furnace, it is ensured that the remaining pollutants in the tail gas are completely burned and decomposed, achieving harmless treatment. The high-temperature flue gas generated by incineration can also further utilize its heat energy to heat the air entering the heating furnace through an air preheater to improve the energy utilization rate and the thermal efficiency of the heating furnace. This treatment method has no impact on the energy consumption and equipment of the existing device's heating furnace.

[0124] Specifically, the cooling medium of the cooling and liquid collection tower can replace the air with other liquids having appropriate boiling points and cooling performance, such as the circulating water used in the device, as long as effective cooling of the tail gas and collection of condensable substances can be achieved.

[0125] Specifically, the lye in the lye absorption tower can select other suitable alkaline substances or mixed lye according to the specific components and content of sulfur-containing substances in the tail gas, such as a mixed solution of potassium hydroxide and sodium hydroxide, etc.

[0126] Specifically, the activated carbon in the activated carbon absorption tower can select activated carbon products with different pore size distributions and materials, or use new adsorption materials to replace activated carbon, as long as it can effectively adsorb the residual pollutants in the tail gas.

[0127] See Figure 1 , Figure 1 which is the process flow diagram of the tail gas treatment system in the production of modified asphalt provided by the present invention. Among them, D-301 is the cooling liquid collection tank, K-301 is the blower, K-302 is the induced draft fan, C-301 is the solvent absorption tower, P-301 / 1 is the circulation pump 1, C-302 is the lye absorption tower, P-301 / 2 is the circulation pump 2, and C-303 is the activated carbon absorption tower.

[0128] According to the process flow diagram, the high-temperature harmful gas of the modified asphalt device → cooling liquid collection tank → induced draft fan → organic solvent absorption tower to remove organic harmful substances (oil components, benzene compounds, etc. are absorbed and enriched) → lye absorption tower to remove inorganic harmful substances (hydrogen sulfide) → harmless discharge → selectively pass through the activated carbon absorption tower → harmless discharge.

[0129] The main reactions are:

[0130] (1) H2S + 2NaOH = Na2S + 2H2O

[0131] (2) Harmful substances at high temperature 800°C + O2 → CO2 + H2O.

[0132] The above content of the present invention provides a tail gas treatment system and treatment method for a modified asphalt device in a refinery. The tail gas treatment system in the production of modified asphalt designed with a specific specific structure and composition of the present invention makes key use of the unique characteristics of the modified asphalt production device in the refinery to centrally incinerate the tail gas generated in the modified asphalt production, storage, and loading sections, fully utilize the large heating furnace system of the adjacent device, eliminate the tail gas exhaust pipe of the device through tail gas transfer, avoid the unorganized emission of the device, and make the tail gas discharged harmlessly through the incineration of the existing device heating furnace. The tail gas treatment system provided by the present invention is a tail gas treatment method that can efficiently remove various pollutants such as macromolecular organic substances and sulfur-containing substances in the tail gas of the modified asphalt device while reducing the treatment cost, realizing the harmless discharge of the tail gas and meeting the environmental protection requirements.

[0133] The present invention adopts a treatment method combining multiple adsorption and incineration. Compared with single adsorption or combustion technology, it can remove various pollutants such as macromolecular organic compounds and sulfur-containing substances in the tail gas more comprehensively and efficiently. Through multi-step treatments such as cooling and liquid collection, solvent adsorption, alkali solution adsorption, and activated carbon adsorption, the purification degree of the tail gas is greatly improved, and the treated tail gas can meet more stringent environmental protection emission standards. Moreover, during the alkali solution adsorption process, by precisely controlling the composition, concentration, and flow rate of the alkali solution, sulfur-containing substances can be targeted for removal, reducing the risk of secondary pollution caused by incomplete combustion of sulfur-containing substances. At the same time, the reasonable application of solvent adsorption and activated carbon adsorption further reduces pollutant emissions and avoids the generation of harmful gases such as dioxins.

[0134] The present invention also provides a corresponding multi-step treatment process. By reasonably designing the process flow and equipment selection, such as the coordinated operation of the tail gas relay fan and the induced draft fan of the large device heating furnace, and the recycling of the coolant in the cooling and liquid collection tower, the overall treatment cost is reduced. Compared with the traditional treatment methods of frequently replacing activated carbon adsorption or high-energy-consuming combustion, it has better economy during long-term operation.

[0135] The tail gas treatment system and its tail gas treatment process provided by the present invention in the production of modified asphalt aim to be an efficient, comprehensive, and environmentally friendly method for treating tail gas in a modified asphalt device in a refinery, solve the existing problems of tail gas treatment, achieve harmless emission of tail gas, reduce environmental pollution, and meet the requirements of relevant environmental protection standards.

[0136] The actual application results show that by using the treatment system and method of the present invention, after continuous detection, the tail gas indexes in the tail gas are: SO2 ≤ 50 mg / m 3 , dust ≤ 10 mg / m 3 , nitrogen oxides 100 mg / m 3 ; far lower than the limits of relevant environmental protection standards.

[0137] Compared with the newly built incinerator: RTO regenerative thermal oxidizer: Generally, the equipment price of an RTO regenerative thermal oxidizer for treating 10,000 m 3 / h is about 300,000 yuan, and the installation cost may range from 100,000 to 200,000 yuan; the annual operating cost: the annual fuel cost for energy consumption is about 1.2 million yuan, and the electricity cost is about 40,000 yuan per year. The present invention can save about 500,000 yuan for building a new incinerator and about 1.25 million yuan in energy consumption costs per year.

[0138] To further illustrate the present invention, the following provides a detailed description of an exhaust gas treatment system and its exhaust gas treatment process in the production of modified asphalt in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given only to further illustrate the features and advantages of the present invention, rather than a limitation on the claims of the present invention. The protection scope of the present invention is not limited to the following embodiments either.

[0139] The present invention has no particular limitation on the source of raw materials in the following embodiments, and they can be prepared by methods well-known to those skilled in the art or purchased commercially.

[0140] Example 1

[0141] This example uses the device system as Figure 1 shown.

[0142] Refer to Table 1. Table 1 shows the relevant parameters of the main equipment of the exhaust gas treatment facility in Example 1 of the present invention.

[0143] Table 1

[0144]

[0145]

[0146]

[0147] 1. Solution parameters in the lye absorption tower

[0148]

[0149] 2. Filling method

[0150] Precautions: The initial filling volume is 500 L. If it exceeds this amount, the solution will overflow into the pipeline along the flue gas inlet. Observe the display of the liquid level gauge during filling. Since the packing in the tower has a blocking effect on the downward flow of the liquid, it is recommended to fill the solution in 2 - 3 times to prevent the liquid level in the tower from exceeding the upper limit of the liquid level.

[0151] 3. Lye replenishment frequency and determination method

[0152] During the production process of modified asphalt, the generation amount of acidic gas is small and affected by various factors, so it is impossible to quantitatively give the consumption of lye. The general principle for replenishing liquid is as follows: When producing 20,000 - 30,000 tons of modified asphalt, the lye in the lye absorption tower needs to be replaced once. Meanwhile, during the operation of the equipment, for the maintenance of the equipment, it is necessary to regularly observe and measure the liquid level of the liquid in the lye absorption tower and the pH value of the solution. Natural evaporation and the water vapor carried by the flue gas during discharge will cause the liquid level to drop, and the liquid level in the absorption tower is strictly prohibited from being lower than the lower limit of the liquid level gauge. As the equipment is used, the concentration of the lye will gradually decrease, so it is necessary to regularly detect the pH value of the solution to ensure the effective absorption of acidic gas by the solution. Since NaOH belongs to a strong base, with the change of concentration, its pH value change cannot be determined by ordinary pH test paper and a more precise detection needs to be carried out with the help of a laboratory equipment acidity meter.

[0153] Laboratory determination of the corresponding relationship between the concentration of NaOH lye and pH value

[0154]

[0155] According to the above corresponding relationship, when pH < 12.5, it is necessary to replenish or replace the lye in time.

[0156] The chemical reaction equation for the lye to absorb hydrogen sulfide is: H2S + 2NaOH = Na2S + 2H2O

[0157] According to the above formula, in 500 liters of 5% NaOH lye, the effective component of NaOH is 25 kg, which can absorb 10.625 kg of H2S. According to the laboratory test data, during the production of modified asphalt, the generation amount of H2S is very low, about 1.5 mg / m 3 , that is, the hourly generation amount is about 1.5 g. Calculated based on the production of 30,000 tons of modified asphalt, the generation amount of H2S is about 0.75 kg. However, in addition to reacting with H2S, NaOH also reacts with carbon dioxide in the air. The absorption of carbon dioxide by the lye is unstable and the chemical reaction is reversible. There are many external influencing factors here. According to the use experience, for every production of 20,000 - 30,000 tons of modified asphalt, the lye needs to be replaced once.

[0158] 4. Treatment method of waste lye:

[0159] The design starting point of this set of tail gas treatment facilities is to make the waste gas of the modified asphalt production device reach environmental protection emissions. During the operation of the equipment, estimated by an annual production of 200,000 tons of modified asphalt, the generation amount of waste lye ≤ 8 - 10 m 3 , and the generation amount of waste lye is not large.

[0160] Organic solvent absorption tower

[0161] 1. Solvent parameters in the organic solvent tower

[0162] The types of solutions, namely Chang Er, Chang San, Jian Er, Jian San or 220# heat-conducting oil, can all be filled in a quantity of 500L each time.

[0163] Replacement frequency: Every time 30,000 tons of modified asphalt are produced (calculated based on a daily output of 500 tons, the replacement cycle is 1.5 - 2 months).

[0164] 2. Filling method

[0165] According to the internal structure and working principle of the absorption tower, the initial filling quantity is 500L. If it exceeds this quantity, the solvent will overflow along the flue gas inlet into the pipeline. When filling, pay attention to observing the display of the liquid level gauge. Due to the blocking effect of the packing in the tower on the downward flow of the liquid, it is recommended to fill the solution in 2 - 3 times to prevent the liquid level in the tower from exceeding the upper limit of the liquid level.

[0166] 3. Refilling frequency and determination method of organic solvents

[0167] During the production process of modified asphalt, the generation amount of organic components in the tail gas is affected by various factors. Therefore, it is impossible to quantitatively give the consumption of organic solvents. The general principle for refilling is: When 20,000 - 30,000 tons of modified asphalt are produced, the solvent in the organic solvent absorption tower needs to be replaced once. At the same time, during the operation of the equipment, the liquid level in the solvent absorption tower should be regularly observed during equipment maintenance. The liquid level of the organic solvent in the absorption tower is strictly prohibited from being lower than the lower limit of the liquid level gauge.

[0168] Laboratory determination: Each liter of organic solvent can absorb about 0.5 - 0.6 kg of tail gas and other harmful organic components. Here, calculated based on the production of 30,000 tons of modified asphalt, with a production capacity of 60T / H, it takes 500 hours to produce 30,000 tons of modified asphalt. The amount of waste gas generated per hour is 330m 3 / h, so the total amount of waste gas generated is 1.65×10 5 m 3 . The main harmful substances and their concentrations in the waste gas are approximately:

[0169]

[0170] The total amount of harmful substances in the waste gas is approximately 330 kg. For this amount of organic harmful substances, a part (about 30%) is condensed and collected in the cooling tower, and the remaining part is about 231 kg. 500L of solvent is added to the solvent tower, which can absorb 250 - 300 kg of organic harmful substances. Therefore, every time 20,000 - 30,000 tons of modified asphalt are produced, the solvent in the organic solvent absorption tower needs to be replaced once.

[0171] The organic solvent absorption tower is different from the caustic solution absorption tower. As the enrichment absorption process progresses, after the organic solvent enriches and absorbs organic matter, its volume and mass increase, and its viscosity increases. When approaching the saturation limit of the absorption liquid, the solvent circulation process is more likely to clog components such as fillers and nozzles. Therefore, it should be replaced in a timely manner when the replacement cycle is reached. Calculated based on the daily production of 500 tons of modified asphalt, the replacement cycle is about 1.5 to 2 months.

[0172] 4. Treatment method for the enriched absorption liquid:

[0173] (1) Combustion treatment to generate CO2 and H2O

[0174] (2) Recycling to the crude oil tank

[0175] (3) As the heavy oil fuel for the heat-conducting oil furnace.

[0176] Treatment effect:

[0177] The purification rate of the tail gas from the modified asphalt production reaches over 97%. After the tail gas is purified, it fully meets the discharge standards and complies with environmental protection requirements. The specific indicators are shown in Table 2. Table 2 shows the treatment effect of the tail gas from the modified asphalt production in Example 1 of the present invention.

[0178] Table 2

[0179]

[0180] The above has introduced in detail the tail gas treatment system and treatment method of a modified asphalt device in a refinery provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A tail gas treatment system in modified asphalt production, characterized in that: include: Exhaust gas collection unit; A cooling and liquid collecting tower connected to the tail gas collecting unit; a solvent absorption tower connected to the cooling and liquid collecting tower; an alkali solution absorption tower connected to the solvent absorption tower; An activated carbon adsorption tower connected to the alkali solution absorption tower.

2. The exhaust gas treatment system according to claim 1, characterized in that: The tail gas collection unit includes an induced draft fan conveying system; The inlet of the induced draft fan conveying system is respectively connected to the smoke pipelines generated by the modified asphalt production tank, the development tank and the loading vehicle; The outlet of the induced draft fan conveying system is connected to the inlet of the cooling liquid collecting tower.

3. The exhaust gas treatment system according to claim 1, characterized in that: The cooling liquid collecting tower is specifically a heat exchange cooling liquid collecting tower with a jacket structure; The heat exchange pipeline of the heat exchange cooling liquid collecting tower is connected to the first blower for air cooling; The tower kettle of the cooling liquid collecting tower is a liquid collecting space; The cooling tail gas outlet of the cooling liquid collecting tower is located between the liquid collecting space and the heat exchange pipeline.

4. The exhaust gas treatment system according to claim 1, characterized in that: The cooling tail gas outlet of the cooling liquid collecting tower is connected to the inlet of the solvent absorption tower through the first induced draft fan; The inlet of the solvent absorption tower is arranged at the lower part of the solvent absorption tower; In the solvent absorption tower, multiple layers of solvent spraying devices of different heights are arranged above the inlet; The outlet of the solvent absorption tower is arranged at the top of the solvent absorption tower.

5. The exhaust gas treatment system according to claim 4, characterized in that: The tail gas treatment system also includes a first circulation pump; The inlet of the first circulation pump is connected to the absorption liquid outlet at the bottom of the solvent absorption tower and the solvent source; The outlets of the first circulation pumps are respectively connected to the inlets of the solvent spraying devices.

6. The exhaust gas treatment system according to claim 1, characterized in that: The outlet of the solvent absorption tower is connected to the inlet of the alkali solution absorption tower; The inlet of the alkali liquid absorption tower is arranged at the lower part of the alkali liquid absorption tower; In the alkali solution absorption tower, an alkali solution spraying device is arranged above the inlet; The outlet of the alkali solution absorption tower is arranged at the top of the solvent absorption tower.

7. The exhaust gas treatment system according to claim 1, characterized in that: The tail gas treatment system also includes a second circulation pump; The inlet of the second circulation pump is connected to the absorption liquid outlet at the bottom of the alkali liquid absorption tower and the alkali liquid source; The outlet of the second circulation pump is connected to the inlet of the alkali solution spraying device; The outlet of the alkali solution absorption tower is connected to the inlet of the activated carbon adsorption tower; The tail gas treatment system also includes an incineration device; The outlet of the activated carbon adsorption tower is connected to the inlet of the incineration device.

8. A tail gas treatment process in modified asphalt production, characterized in that: The following steps are involved: 1) One or more of the fumes generated by the modified asphalt production tank, the development tank and the loading vehicle are collected by an induced draft fan to obtain tail gas to be treated, and then transported to a cooling liquid collecting tower, and after air cooling and heat exchange, cooled tail gas is obtained; 2) sending the cooled tail gas obtained in the above step into a solvent adsorption tower, and spraying it with multiple layers of organic solvent from bottom to top to obtain tail gas after solvent adsorption; 3) sending the tail gas after solvent adsorption obtained in the above step into an alkali solution adsorption tower, and spraying it with multiple layers of alkaline solution from bottom to top to obtain the tail gas after alkali solution adsorption; 4) The tail gas obtained in the above step after the alkali solution adsorption is adsorbed on activated carbon to obtain treated tail gas.

9. The tail gas treatment process according to claim 8, characterized in that: The tail gas to be treated includes oil, aromatic hydrocarbon compounds, hydrogen sulfide, asphalt smoke and dust; The aromatic hydrocarbon compound includes benzo[a]pyrene; The temperature of the tail gas to be treated is 70-100°C; The temperature of the cooling tail gas is 40-60°C; The number of layers of the multilayer is 2 to 5; The organic solvent includes one or more of diesel, n-hexane and xylene.

10. The tail gas treatment process according to claim 8, characterized in that: The alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution; The modified asphalt is specifically SBS series modified asphalt and / or durable high modulus asphalt; In the tail gas after treatment, SO2≤50mg / m 3 ; The dust in the treated tail gas is ≤10mg / m 3 ; In the tail gas after treatment, nitrogen oxides ≤ 100 mg / m 3 ; The treated tail gas also includes a step of incineration.

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