Method for regulating the temperature stability of inorganic material solidified petroleum contaminated soil

Abstract

The application discloses a method for regulating the viscosity stability of solidified petroleum contaminated soil by inorganic materials, which comprises the following steps: S1, preparing petroleum contaminated soil according to a certain water content; S2, adding a viscosity index improver into the petroleum contaminated soil and stirring uniformly; S3, adding inorganic solidification materials into the petroleum contaminated soil and stirring uniformly; and S4, compacting and sealing, and curing under a certain temperature and humidity for a to days until the solidification reaction is stable. The petroleum contaminated soil is treated by the method, the viscosity index improver and the inorganic solidification materials are added into the petroleum contaminated soil, the viscosity stability of different occurrence forms of petroleum pollutants is controlled by the synergistic solidification of the inorganic solidification materials and the viscosity index improver, the environmental pollution problems of secondary migration and diffusion of pollutants and the structure instability problems of water-physical and mechanical performance fluctuation caused by climate and temperature difference changes in the process of engineering reuse of the existing solidified petroleum contaminated soil are solved, and the harmless and ecological engineering reuse of the petroleum contaminated soil is realized.

Description

Technical Field

[0001] This invention belongs to the field of petroleum contaminated soil remediation technology, and particularly relates to a method for regulating the viscosity-temperature stability of inorganic materials used to solidify petroleum contaminated soil. Background Technology

[0002] Industry is the leading sector of the national economy. Petroleum not only provides a reliable and abundant energy source for industrial production, but it is also an indispensable raw material in many industrial sectors, playing a vital role in driving national industrial development. However, oil spills are inevitable during the extraction and use of oil. Petroleum pollutants not only disrupt the balance of the natural ecological environment but also negatively impact soil mechanical properties. Petroleum pollutants in the soil alter the structure of soil microbial communities, hindering the normal growth of surface vegetation. Furthermore, the migratory nature of petroleum in soil allows pollutants to continuously diffuse and infiltrate, significantly increasing the risk of groundwater contamination.

[0003] Petroleum is a temperature-sensitive fluid, and the viscosity coefficient of petroleum-contaminated soil is easily affected by the ambient temperature. This not only directly impacts the engineering stability during the reuse of solidified contaminated soil but can also trigger the re-desorption and migration of petroleum pollutants, seriously endangering the ecological environment and groundwater safety. Therefore, it is necessary to seek technologies to regulate the viscosity-temperature stability of solidified petroleum-contaminated soil.

[0004] Based on the above problems, this invention proposes a method for regulating the viscosity-temperature stability of solidified petroleum contaminated soil. By combining the solidification effects of viscosity-temperature index improvers, lime, and fly ash, the method not only achieves mechanical stability of the solidified contaminated soil but also mitigates the viscosity changes of petroleum pollutants caused by temperature variations. This effectively improves the viscosity-temperature stability of inorganically solidified petroleum contaminated soil, enabling the green, environmentally friendly, and sustainable engineering reuse of petroleum contaminated soil. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for regulating the viscosity-temperature stability of inorganic materials used to solidify petroleum-contaminated soil. The solidification materials are readily available and inexpensive, and the solidification method is simple and easy to implement on-site. This method effectively controls the viscosity-temperature stability of the solidified petroleum-contaminated soil, creating favorable conditions for the harmless and ecologically sustainable reuse of petroleum-contaminated soil and solving the problems in the background technology.

[0006] This invention provides the following technical solution:

[0007] A method for regulating the viscosity-temperature stability of inorganic materials solidified petroleum-contaminated soil, characterized by comprising the following steps:

[0008] S1. Prepare petroleum-contaminated soil according to a certain moisture content;

[0009] S2. Add viscosity index improver to petroleum-contaminated soil and stir evenly;

[0010] S3. Add inorganic solidification material to the petroleum-contaminated soil and stir evenly;

[0011] S4. Compact and seal, then cure for a day under certain temperature and humidity until the curing reaction stabilizes.

[0012] Further, in step S1, the preparation of the petroleum-contaminated soil includes the following steps:

[0013] S11. Pass the dried and pulverized coastal saline soil through a 2mm sieve and weigh an appropriate amount of saline soil.

[0014] S12. Based on the weight of the saline soil weighed in step S11, add 17.7% water to the saline soil, seal and store for 24 hours.

[0015] S13. After standing, add petroleum at 6%-21% of the mass of the saline soil weighed in step S11, seal and stand for 7 days.

[0016] Furthermore, the viscosity index improver is T614 ethylene-propylene copolymer or T602HB polymethyl methacrylate.

[0017] Further, in step S2, the incorporation of the viscosity index improver includes the following steps:

[0018] S21. Add T614 ethylene-propylene copolymer to the petroleum-contaminated soil at 7% of the mass of the petroleum added in step S13.

[0019] S22. Add T602HB polymethyl methacrylate to the petroleum-contaminated soil at 8% of the mass of the petroleum added in step S13.

[0020] S23, allow it to remain sealed at room temperature for b days to allow it to fully react with the petroleum-contaminated soil.

[0021] Furthermore, the value of b is 6-8 days, preferably 7 days.

[0022] Furthermore, the inorganic curing material is lime and fly ash.

[0023] Further, the mass of lime added is 10% of the mass of the saline soil weighed in step S11; the mass of fly ash added is 20% of the mass of the saline soil weighed in step S11.

[0024] Further, in step S4, the maintenance method includes the following steps:

[0025] S41. Use a ring cutter and a manual light compactor to compact the soil sample and place it in a sealed bag;

[0026] S42. Place the soil sample in a curing chamber for curing at a curing temperature of t℃, a curing humidity of ≥95%, and a curing period of a days.

[0027] Furthermore, the value of t is 18-22℃, preferably 20℃.

[0028] Furthermore, the value of 'a' is 27-29 days, preferably 28 days.

[0029] Furthermore, it also includes step S43, in which the cured samples are placed in constant temperature and humidity environments of 0℃, 10℃, 25℃, 40℃, 60℃, and 80℃ respectively and sealed and stabilized for 8 hours.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention provides a method for regulating the viscosity-temperature stability of inorganic material-cured petroleum-contaminated soil. The inorganic material curing treatment of petroleum-contaminated soil effectively controls the diffusion and migration of petroleum pollutants in the soil. On this basis, a viscosity index improver is added to the petroleum-contaminated soil. The molecular chain extension and expansion of the effective substances in the composite viscosity index improver and the increase of hydrodynamic area enhance the internal friction effect on petroleum, stabilize the thickening performance of petroleum, improve the sensitivity of petroleum under temperature difference, and further reduce the temperature sensitivity of the cured petroleum-contaminated soil.

[0032] (2) The present invention provides a method for regulating the viscosity-temperature stability of inorganic solidified petroleum contaminated soil. The composite viscosity index improver is readily available and inexpensive. Adding a small amount of improver can achieve significant results. It not only ensures the stability of the viscosity-temperature and engineering properties of the solidified petroleum contaminated soil, but also has the advantage of high economic benefits. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] Combination Figure 1 As shown, a method for regulating the viscosity-temperature stability of inorganic materials solidified petroleum-contaminated soil includes the following steps:

[0038] The moisture content of the coastal saline soil was adjusted to the optimum moisture content. In order to obtain the maximum degree of compaction of the saline soil sample, according to the "Specifications for Geotechnical Testing of Highways" (JTG E40-2007), the saline soil was air-dried and passed through a 2mm sieve, and the saline soil sample was controlled to reach the optimum moisture content of 17.7%, and then sealed and stored at room temperature under constant temperature and humidity for 24 hours.

[0039] Petroleum-contaminated saline soil was prepared by adding petroleum to soil samples. Considering the saturation of the saline soil and the actual pollution level of the petroleum-contaminated soil, the amount of petroleum added was 6%-21% of the mass of the saline soil to simulate the actual petroleum-contaminated environment, and the sealing stabilization time was 24 hours.

[0040] Viscosity index improvers were added to petroleum-contaminated soil and stirred thoroughly, then allowed to stabilize in a sealed container at room temperature. Considering the appropriate addition amount of viscosity index improvers in petroleum products, the addition contents of T614 and T602HB improvers were 7% and 8% of the petroleum mass, respectively, with a stabilization time of 7 days.

[0041] Inorganic solidification material is added to petroleum-contaminated saline soil, mixed evenly, and cured to obtain solidified petroleum-contaminated soil. Referring to the suitable mix ratio for lime-fly ash solidification treatment of petroleum-contaminated soil, the amount of lime added is 10% of the mass percentage of the saline soil, and the amount of fly ash added is 20% of the mass percentage of the saline soil.

[0042] The soil samples were compacted using a manual light compactor and then sealed and cured under constant temperature and humidity conditions. The temperature during the entire curing period was 20±2℃, the humidity was greater than 95%, and the curing period was 28 days.

[0043] Petroleum is a non-aqueous organic compound whose viscosity is sensitive to external temperature. Generally, the viscosity of petroleum tends to decrease with increasing temperature. Therefore, petroleum contaminants in soil are unstable and prone to diffusion and migration, easily leading to secondary pollution. Furthermore, the temperature sensitivity of petroleum also means that the mechanical properties of petroleum-contaminated soil are affected by external temperature. Therefore, the engineering utilization of petroleum-contaminated soil requires not only remediation but also improvement of its viscosity-temperature stability. Simultaneously, to align with sustainable development strategies, solidification materials and viscosity index improvers should be inexpensive and pollution-free.

[0044] By utilizing the pozzolanic reaction and solidification reaction of lime and fly ash to adsorb petroleum pollutants and generate hydrogel compounds that act as cementing agents between soil particles, the strength of petroleum-contaminated soil is effectively improved. Adding a viscosity index improver to the petroleum-contaminated soil mitigates the significant viscosity performance differences caused by external temperature variations during its engineering application by improving the viscosity-temperature properties of petroleum.

[0045] Viscosity index improvers are typically high-molecular-weight organic compounds, solid or rubbery at room temperature. They are generally diluted with neutral oil to form a viscous fluid with an effective substance content of 5%-10%. As temperature increases, the polymer chains of the viscosity index improver gradually extend, increasing frictional resistance to oil molecules and thus increasing viscosity. Conversely, at low temperatures, the polymer chains gradually contract, reducing internal friction on oil molecules and having little effect on viscosity. Compared to oils without improvers, oils with improvers exhibit higher viscosity and smoother viscosity-temperature profiles.

[0046] Lime and fly ash undergo physical and chemical reactions to adsorb and stabilize petroleum contaminants. Simultaneously, the resulting hydrogel compounds act as a binder between soil particles, effectively improving the strength of petroleum-contaminated soil. Adding a viscosity index improver to the petroleum-contaminated soil mitigates engineering instability caused by changes in external temperature during its use, by improving the viscosity-temperature properties of petroleum.

[0047] As an optimization, the solidified petroleum-contaminated soil, fly ash, lime, and saline soil all need to pass through a 2mm sieve. This removes impurities, ensures all materials can react fully, and reduces experimental error.

[0048] As an optimization, the moisture content of petroleum-contaminated saline soil is controlled at 17.7%. This helps the fly ash and lime in the soil to react fully with water, generating hydration products such as hydrated calcium silicate, which then bind with soil particles, thereby improving the engineering strength of the contaminated soil.

[0049] As an optimization, controlling different oil contents and different viscosity index improver dosages is to simulate the viscosity coefficient of solidified petroleum-contaminated saline soil with different pollution levels in actual engineering, as well as the influence of different types and contents of viscosity index improvers on the viscosity coefficient of solidified petroleum-contaminated saline soil.

[0050] As an optimization, the curing materials fly ash and lime are inexpensive, and the viscosity index improvers T602HB polymethyl methacrylate and T614 ethylene propylene copolymer are added in small amounts and are inexpensive, which reduces resource consumption, is environmentally friendly, and is in line with the strategy of sustainable development.

[0051] As an optimization, the samples were placed in a constant temperature and humidity curing chamber for curing. The temperature during the entire curing period was (20±2)℃, the humidity was greater than 95%, and the curing period was 28 days. This allowed the lime, fly ash, and viscosity-temperature index improver to fully react with the soil samples.

[0052] The experiment selected six concentrations of petroleum-contaminated soil, with petroleum addition amounts of 6%, 9%, 12%, 15%, 18%, and 21% of the dry soil mass, respectively. A control group was set up for each of the petroleum-contaminated soils with different pollution levels.

[0053] Example 1

[0054] To ensure the accuracy of the experiment, the dried and pulverized coastal saline soil was sieved through a 2mm sieve. An appropriate amount of saline soil was weighed, and 17.7% water was added to it based on the dry soil weight. The mixture was sealed and left to stand for 24 hours. After standing, 6% petroleum was added based on the dry soil weight, and the mixture was sealed and left to stand for 7 days to simulate an outdoor petroleum pollution environment. Based on the petroleum weight in the soil, 7% T614 and 8% T602HB were added to the petroleum-contaminated soil, and the mixture was thoroughly stirred. The mixture was then sealed and left to stand at room temperature for 24 hours. Simultaneously, based on the dry soil weight, 10% lime and 20% fly ash were weighed and thoroughly stirred.

[0055] The soil sample was pressed using a ring cutter and sealed under constant temperature and humidity conditions for stabilization. Vaseline was thoroughly applied to the inner wall of the ring cutter to reduce friction between soil particles and the inner wall. Simultaneously, soil sample was loaded into the ring cutter, and the ring cutter was pressed vertically downwards, cutting and compacting until the soil sample extended beyond the ring cutter. The soil sample was then compacted using a manual light compactor and placed in a curing chamber for stable storage. The sample diameter was 61.8 mm, and the height was 20 mm. The temperature during the entire curing period was (20±2)℃, the humidity was greater than 95%, and the curing period was 28 days.

[0056] After curing, the samples were sealed and stabilized for 8 hours in constant temperature and humidity environments at 0℃, 10℃, 25℃, 40℃, 60℃, and 80℃.

[0057] Example 2

[0058] The dried and pulverized coastal saline soil was sieved through a 2mm sieve. An appropriate amount of saline soil was weighed, and 17.7% water was added to the saline soil based on its dry weight. The mixture was sealed and left to stand for 24 hours. After standing, 9% petroleum was added based on the dry soil weight, and the mixture was sealed and left to stand for 7 days to simulate an outdoor petroleum contamination environment. Based on the petroleum weight in the soil, 7% T614 and 8% T602HB were added to the petroleum-contaminated soil, and the mixture was thoroughly stirred. The mixture was then sealed and left to stand at room temperature for 24 hours. At the same time, based on the dry soil weight, 10% lime and 20% fly ash were weighed and thoroughly stirred.

[0059] The other steps are the same as in Example 1.

[0060] Example 3

[0061] The amount of petroleum added was 12% of the dry soil mass, and the other steps were the same as in Example 1.

[0062] Example 4

[0063] The amount of petroleum added was 15% of the dry soil mass, and the other steps were the same as in Example 1.

[0064] Example 5

[0065] The amount of petroleum added was 18% of the dry soil mass, and the other steps were the same as in Example 1.

[0066] Example 6

[0067] The amount of petroleum added was 21% of the dry soil mass, and the other steps were the same as in Example 1.

[0068] Comparative Example 1

[0069] After drying and pulverizing, the coastal saline soil is sieved through a 2mm sieve. An appropriate amount of saline soil is weighed, and 17.7% water is added to the saline soil based on its dry weight. The mixture is then sealed and left to stand for 24 hours. After standing, 6% petroleum is added based on the dry soil weight, and the mixture is sealed and left to stand for 7 days. At the same time, 10% lime and 20% fly ash are weighed and thoroughly mixed.

[0070] The soil sample was pressed using a ring cutter and sealed under constant temperature and humidity conditions for stabilization. Vaseline was thoroughly applied to the inner wall of the ring cutter to reduce friction between soil particles and the inner wall. Simultaneously, soil sample was loaded into the ring cutter, and the ring cutter was pressed vertically downwards, cutting and compacting until the soil sample extended beyond the ring cutter. The soil sample was then compacted using a manual light compactor and placed in a curing chamber for stable storage. The sample diameter was 61.8 mm, and the height was 20 mm. The temperature during the entire curing period was (20±2)℃, the humidity was greater than 95%, and the curing period was 28 days.

[0071] After curing, the samples were sealed and stabilized for 8 hours in constant temperature and humidity environments at 0℃, 10℃, 25℃, 40℃, 60℃, and 80℃.

[0072] Comparative Example 2

[0073] The amount of petroleum added was 9% of the dry soil mass, and the other steps were the same as those in Comparative Example 1.

[0074] Comparative Example 3

[0075] The amount of petroleum added was 12% of the dry soil mass, and the other steps were the same as those in Comparative Example 1.

[0076] Comparative Example 4

[0077] The amount of petroleum added was 15% of the dry soil mass, and the other steps were the same as those in Comparative Example 1.

[0078] Comparative Example 5

[0079] The amount of petroleum added was 18% of the dry soil mass, and the other steps were the same as those in Comparative Example 1.

[0080] Comparative Example 6

[0081] The amount of petroleum added was 21% of the dry soil mass, and the other steps were the same as those in Comparative Example 1.

[0082] Table 1 shows the viscosity coefficients of solidified petroleum-contaminated soil with different petroleum contents under varying temperature conditions.

[0083] Table 1. Viscosity coefficients of petroleum-contaminated soil from Examples 1-6 and Comparative Examples 1-6 at different temperatures.

[0084]

[0085] As shown in Table 1, the variation rate of viscosity coefficient between adjacent temperatures for solidified petroleum-contaminated soil with added viscosity index improver ranged from 3.51% to 6.10%, 2.76% to 6.34%, 1.33% to 8.17%, 1.49% to 10.98%, 4.06% to 9.95%, and 4.27% to 11.53%, respectively. Compared with the variation rate of viscosity coefficient between adjacent temperatures for solidified petroleum-contaminated soil without added viscosity index improver at the same contamination level, all of these ranges showed a certain degree of reduction. This indicates that as the temperature increases, the molecular chains of the viscosity index improver expand, changing the hydrodynamic surface area of ​​the molecular chains. This increases the internal friction force on the petroleum in the soil, correspondingly increasing the viscosity of the petroleum and reducing the variation rate of petroleum viscosity under the same temperature change, thus playing a role in controlling the viscosity-temperature change of petroleum-contaminated soil.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations; any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating the viscosity-temperature stability of inorganic materials solidified petroleum-contaminated soil, characterized in that, Includes the following steps: S1. Prepare petroleum-contaminated soil according to a certain moisture content; S2. Add a viscosity index improver to the petroleum-contaminated soil and stir evenly. The viscosity index improver is T614 ethylene-propylene copolymer and T602HB polymethyl methacrylate. Add T614 ethylene-propylene copolymer to the petroleum-contaminated soil at 7% of the mass of petroleum in the petroleum-contaminated soil prepared in step S1, and add T602HB polymethyl methacrylate to the petroleum-contaminated soil at 8% of the mass of petroleum in the petroleum-contaminated soil prepared in step S1. Seal and stabilize at room temperature for 6-8 days to allow it to fully contact and react with the petroleum-contaminated soil. S3. Add inorganic solidification material to the petroleum-contaminated soil and stir evenly; S4. Compact and seal, and cure for 28 days under certain temperature and humidity until the curing reaction is stable; after curing, the samples are placed in constant temperature and humidity environments of 0°C, 10°C, 25°C, 40°C, 60°C, and 80°C respectively and sealed and stabilized for 8 hours. The inorganic solidification material is lime and fly ash; the added mass of lime is 10% of the mass of the saline soil weighed in step S2; the added mass of fly ash is 20% of the mass of the saline soil weighed in step S2.

2. The method for regulating the viscosity-temperature stability of inorganic materials solidified petroleum-contaminated soil according to claim 1, characterized in that, In step S1, the preparation of the petroleum-contaminated soil includes the following steps: S11. Pass the dried and pulverized coastal saline soil through a 2 mm sieve and weigh an appropriate amount of saline soil. S12. Based on the weight of the saline soil weighed in step S11, add 17.7% water to the saline soil, seal and store for 24 hours. S13. After standing, add petroleum at 6%-21% of the mass of the saline soil weighed in step S11, seal and stand for 7 days.

3. The method for regulating the viscosity-temperature stability of inorganic materials solidified petroleum-contaminated soil according to claim 1, characterized in that, In step S4, the maintenance method includes the following steps: S41. Use a ring cutter and a manual light compactor to compact the soil sample and place it in a sealed bag; S42. Place the soil sample in a curing chamber for curing. The curing temperature is 18-22℃, the curing humidity is greater than or equal to 95%, and the curing period is 28 days.

Images