Method for inhibiting sulfate-reducing bacteria in salt cavern hydrogen storage projects

Abstract

The application discloses a method for inhibiting sulfate-reducing bacteria (SRB) in a salt cave hydrogen storage project, and belongs to the technical field of hydrogen energy storage. The method uses salt-tolerant hydrogen-producing microorganisms to perform anaerobic fermentation on the inner wall of the salt cave by using a glycerol-polyacrylamide-glycerol ring layer, so that hydrogen and volatile acid metabolites are generated, and the sulfate-reducing bacteria are inhibited. The volatile fatty acids have a significant inhibitory effect on the SRB in a high-salt environment. The application provides an efficient and environmentally-friendly SRB inhibition method in the salt cave hydrogen storage project, thereby reducing the generation of harmful gas hydrogen sulfide in the salt cave and effectively reducing the corrosion risk of hydrogen sulfide.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy storage technology. Specifically, it discloses a method for inhibiting sulfate-reducing bacteria (SRB) in salt cavern hydrogen storage projects. Hydrogen-producing microorganisms utilize a glycerol-polyacrylamide-glycerol ring to conduct anaerobic fermentation on the inner wall of the salt cavern, producing hydrogen and volatile acid metabolites. This method, which inhibits the growth of sulfate-reducing bacteria and the production of hydrogen sulfide within the salt cavern by producing volatile fatty acids through metabolism, is applicable to microbial corrosion control in salt cavern hydrogen storage projects. Background Technology

[0002] Hydrogen is a crucial carrier in the new energy system. Among the four stages of the hydrogen energy industry chain—preparation, transportation, storage, and application—hydrogen storage and transportation are the main challenges. Salt cavern gas storage, due to its strong peak-shaving capacity, high injection and production efficiency, low requirement for subbase gas volume, strong sealing capacity of rock salt, and flexible operation, is currently considered one of the most promising underground hydrogen storage methods. Choosing salt cavern hydrogen storage as an efficient and environmentally friendly method has broad application prospects in the energy storage field. Microorganisms within salt caverns are closely related to hydrogen consumption, production, and corrosion. Many frequently occurring microorganisms are considered major hydrogen consumers, such as methanogens, sulfate-reducing bacteria (SRB), and acetic acid bacteria. Among these, SRB present in the salt cavern environment can cause serious damage to hydrogen storage systems. SRB can reduce sulfate to hydrogen sulfide under anaerobic conditions. Hydrogen sulfide is not only a harmful gas that contaminates stored hydrogen and reduces its quality, but it is also highly corrosive, causing depolarization in steel, inducing severe pitting corrosion, and promoting hydrogen-induced cracking (HIC) and sulfide stress corrosion cracking (SSCC), thus affecting the safety of hydrogen storage and posing risks to hydrogen storage.

[0003] Currently, most methods for inhibiting SRB corrosion in salt caverns suffer from low efficiency, high cost, or potential environmental hazards. Based on factors such as SRB growth and reproduction conditions, corrosion mechanisms, and target organisms, commonly used SRB corrosion control methods can be categorized into physical methods, anti-corrosion materials, cathodic protection, chemical methods, and microbial control methods. Physical methods inhibit SRB activity by altering environmental conditions such as temperature, pH, mineralization, dissolved oxygen, ultraviolet radiation, and ultrasound. However, physical methods are energy-intensive, difficult to control, and have poor bactericidal effects, making them challenging to implement in salt cavern SRB treatment. While chemical bactericides can inhibit SRB growth to some extent, they may cause secondary pollution to the salt cavern environment and hydrogen storage system, and long-term use can easily lead to SRB resistance. Therefore, developing an efficient and environmentally friendly SRB inhibition method is crucial for ensuring the safe and stable operation of salt cavern hydrogen storage projects. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for inhibiting the growth of sulfate-reducing bacteria in salt cavern hydrogen storage projects, so as to solve the hydrogen sulfide pollution and corrosion problems caused by SRB in salt cavern hydrogen storage projects.

[0005] This invention provides a method for inhibiting the growth of sulfate-reducing bacteria in salt cavern hydrogen storage engineering, comprising the following steps:

[0006] S1 mixes glycerol and brine to form glycerol solution I, which is then injected into the salt cavern through the central tube;

[0007] S2 introduces dry air into the salt cavern through the production casing, while simultaneously discharging the glycerol solution;

[0008] S3 injects the polyacrylamide solution from the central tube into the salt cavern;

[0009] S4 introduces oxygen-controlled air containing potassium persulfate mist into the salt cavern from the production casing, while simultaneously discharging the polyacrylamide solution; potassium persulfate and oxygen-controlled air facilitate the coagulation of glycerol polyacrylamide. Trace amounts of O2 act as co-initiators for free radical initiators, helping potassium persulfate decompose to generate sulfate radicals (SO4⁻·), accelerating the crosslinking of polyacrylamide.

[0010] S5 then injects glycerol solution II from the central tube into the salt cavity;

[0011] S6 employs an appropriate drying process to construct a glycerol-polyacrylamide-glycerol ring on the inner wall of the salt cave.

[0012] S7 Inoculate the halophilic hydrogen-producing and acid-producing microorganisms onto the glycerol-polyacrylamide-glycerol ring, so that the halophilic hydrogen-producing and acid-producing microorganisms can carry out anaerobic fermentation using the glycerol in the glycerol-polyacrylamide-glycerol ring in the high-salt anaerobic environment of the salt cave.

[0013] S8 monitors parameters such as temperature, pH, hydrogen concentration, volatile acid concentration, and hydrogen sulfide concentration in the salt cavern in real time, and adjusts the gas flow rate, injection of glycerol and molybdate solution in the salt cavern according to the monitoring data to optimize the fermentation environment of the halophilic hydrogen-producing and acid-producing microorganisms.

[0014] S9 injects high-pressure hydrogen and stores the hydrogen in a sealed environment.

[0015] Further, the glycerol solution I described in step S1 has a mass fraction of 5%-10%.

[0016] Further, in step S2, dry air is introduced and the gas flow rate is controlled at 0.5-1 m / s to allow it to initially solidify and adhere.

[0017] Furthermore, the mass fraction of the polyacrylamide solution in step S3 is 1%-2%, and the solvent is brine.

[0018] Further, in step S4, the oxygen-controlled air containing potassium persulfate aerosol is controlled at an airflow velocity of 0.5-1 m / s. The concentration of the potassium persulfate aerosol is 0.3-0.6%. Trace amounts of oxygen can initiate free radical reactions, promoting the initial solidification of glycerol and polyacrylamide in combination with potassium persulfate on the inner wall of the salt cavern, forming a base layer with certain adhesiveness. The trace oxygen content is 1-5% VOL.

[0019] Furthermore, the glycerol solution II mentioned in step S5 has a mass fraction of 15% - 25%, and the solvent is brine.

[0020] Further, the appropriate drying process described in step S6 involves introducing dry nitrogen gas at a flow rate of 0.5-1 m / s to allow the glycerol to solidify and form layers, and then allowing it to stand for 12 hours to form a glycerol-polyacrylamide-glycerol layer.

[0021] Furthermore, the thickness of the glycerol-polyacrylamide-glycerol layer is 0.5-1 cm.

[0022] Furthermore, the halophilic hydrogen-producing and acid-producing microorganisms mentioned in step S7 are anaerobic fermentation microorganisms that produce hydrogen and can inhibit sulfate-reducing bacteria. The inoculation method involves introducing the microorganisms into the cavity with the brine and allowing it to stand for 24 hours. Then, hydrogen gas is slowly introduced through the production sleeve, and the brine is slowly discharged, allowing the microorganisms to adhere to the glycerol-polyacrylamide-glycerol layer. Finally, the cavity is sealed for 48 hours for anaerobic fermentation.

[0023] Furthermore, the anaerobic fermentation microorganisms that produce hydrogen and inhibit sulfate-reducing bacteria include, but are not limited to, those belonging to the genera *Clostridium* or *Enterobacter*; they are capable of metabolizing glycerol to produce hydrogen gas, with a hydrogen production rate ≥ 1.2 mol H2 / mol glycerol. Simultaneously, the organic acids (acetic acid, butyric acid, etc.) produced during fermentation, when the environmental pH is ≤ 6.5, inhibit the production of hydrogen sulfide by sulfate-reducing bacteria.

[0024] Further, the method of injecting glycerol and molybdate solution in step S8: when the concentration (volume fraction) of volatile acid is monitored to drop to 10 ppm, glycerol is injected into the salt cave to promote the fermentation of the halophilic hydrogen-producing and acid-producing microorganisms and increase acid production; when the inhibitory effect of glycerol on acid production reaches an extreme value, that is, when the hydrogen sulfide concentration is higher than 12 ppm, molybdate solution is added from the central tube to achieve the inhibitory effect on SRB.

[0025] Furthermore, the concentration of the molybdate solution is 10-50 μM.

[0026] Furthermore, this method reduces the amount of hydrogen sulfide produced in salt caverns by more than 85%.

[0027] This invention utilizes microorganisms to perform anaerobic fermentation of glycerol in a high-salt environment. In the high-salt environment of hydrogen storage in salt caves, an appropriate amount of glycerol is provided as the fermentation substrate. Glycerol has strong fluidity on the inner wall of the salt cave, resulting in a thin single glycerol layer. Adding polyacrylamide moderately increases the viscosity of the glycerol, which helps to form a glycerol ring on the inner wall of the salt cave. Halophilic hydrogen-producing microorganisms utilize the glycerol-polyacrylamide-glycerol ring to produce hydrogen and volatile acid metabolites on the inner wall of the salt cave. Volatile fatty acids (such as acetic acid) can inhibit the growth of SRBs through various mechanisms, such as altering the pH value within SRB cells, affecting their enzyme activity, and thus interfering with the normal metabolic processes of SRBs; acetic acid may also compete with substrates in the SRB metabolic process for enzyme binding sites, hindering the utilization of nutrients by SRBs, thereby inhibiting their growth and reproduction.

[0028] The method of this invention can efficiently and environmentally suppress the growth of SRB (sulfur-reducing oxalate) and reduce the generation of harmful hydrogen sulfide gas within salt caverns in hydrogen storage projects. Simultaneously, the reduced hydrogen sulfide production effectively lowers the risk of corrosion to salt cavern structural materials and hydrogen storage equipment, ensuring the safe and stable operation of the salt cavern hydrogen storage system and improving the quality and efficiency of hydrogen energy storage. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 This is a schematic diagram of a salt cavern structure;

[0031] Figure 2 This is a process diagram of injecting glycerol solution I at S1 in Example 1;

[0032] Figure 3 This is a process diagram of introducing dry air at S2 in Example 1;

[0033] Figure 4 This is a schematic diagram of the S2 glycerol ring in Example 1;

[0034] Figure 5 This is a process diagram of injecting polyacrylamide solution at S3 in Example 1;

[0035] Figure 6 This is a process diagram of introducing oxygen-controlled air containing potassium persulfate mist in S4 of Example 1;

[0036] Figure 7 This is a schematic diagram of the S5 glycerol-polyacrylamide ring in Example 1;

[0037] Figure 8 This is a process diagram of injecting glycerol solution II at S5 in Example 1;

[0038] Figure 9 This is a process diagram of introducing dry nitrogen gas at S6 in Example 1;

[0039] Figure 10 This is a schematic diagram of the S6 glycerol-polyacrylamide-glycerol ring in Example 1;

[0040] Figure 11 This is a diagram of the microbial inoculation process in Example 1 (S7).

[0041] Figure 12 This is a process diagram of adding molybdate solution at S8 in Example 1;

[0042] In the diagram: 1. Salt cavern, 2. Central tube, 3. Production casing, 4. Inner wall of salt cavern, 5. Glycerin solution I (7%), 6. Dry air, 7. Glycerin ring, 8. Polyacrylamide solution (1%), 9. Oxygen-controlled air containing potassium persulfate mist, 10. Glycerin-polyacrylamide ring, 11. Glycerin solution II (15%), 12. Dry nitrogen, 13. Glycerin-polyacrylamide-glycerin ring, 14. Brine containing microorganisms, 15. Sodium molybdate solution. Detailed Implementation

[0043] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0044] In implementing this invention, suitable halophilic microorganisms are first extracted and screened, and their optimal growth parameters are determined. Next, a glycerol-polyacrylamide-glycerol layer is constructed, and high-pressure hydrogen gas containing the halophilic microorganisms is injected to ensure sufficient contact between the glycerol and the glycerol on the inner wall of the salt cave. Then, the parameters are adjusted to induce anaerobic fermentation of glycerol in the salt cave environment to produce hydrogen, while simultaneously generating organic acid metabolites. Among these, volatile fatty acids exhibit a significant inhibitory effect on SRB (sulfate-induced basal inflammatory disease) under high-salt conditions. Example 1

[0045] Taking Jintan salt caverns as an example, a method for inhibiting the growth of sulfate-reducing bacteria in salt cavern hydrogen storage projects includes the following specific steps:

[0046] S1 mixes glycerol and brine to form a glycerol solution, which is then injected into the salt cavern through the central tube. The mass concentration of the glycerol-brine solution is 7%.

[0047] S2 introduces air into the salt cavern through the production casing, while simultaneously discharging the glycerol solution. The gas flow rate is controlled at 0.5-1 m / s, causing the first layer of glycerol to initially solidify and adhere to the inner wall of the salt cavern, while the glycerol solution is discharged at the same time.

[0048] S3 injects brine containing polyacrylamide into the salt through the central tube. The mass concentration of the polyacrylamide brine solution is 1%.

[0049] S4 introduces oxygen-controlled air containing potassium persulfate mist into the salt cavern from the production casing, while simultaneously discharging brine containing polyacrylamide. The airflow velocity is controlled at 1 m / s. The potassium persulfate mist concentration is 0.6%. Trace amounts of oxygen can initiate free radical reactions, promoting the initial solidification of glycerol and polyacrylamide with potassium persulfate on the inner wall of the salt cavern, forming a base layer with certain adhesiveness. The trace oxygen content is 1-5% VOL.

[0050] S5 injects a brine solution containing 15% glycerol into the salt cavern from the central tube.

[0051] Dry nitrogen gas is introduced into S6 at a flow rate of 1 m / s to allow glycerol to solidify and form layers. After standing for 12 hours, a glycerol-polyacrylamide-glycerol layer is formed. The layer thickness constructed on the inner wall of the salt cave is 1 cm.

[0052] S7. Clostridium butyricum (MCCC 1A19159), belonging to the genus Clostridium, is injected into the salt cave along with brine and inoculated onto the glycerol-polyacrylamide-glycerol ring, so that the hydrogen-producing microorganisms can carry out anaerobic fermentation using the glycerol in the glycerol-polyacrylamide-glycerol ring in the high-salt anaerobic environment of the salt cave.

[0053] S8 monitors the temperature, pH, hydrogen concentration, volatile acid concentration, and hydrogen sulfide concentration in the salt cavern in real time. When a decrease in volatile acid concentration is detected, glycerol is injected into the salt cavern to promote the fermentation of the halophilic microorganisms and increase acid production. When an upward trend in SRB activity is detected, 20 μM sodium molybdate solution is added from the central tube to inhibit SRB.

[0054] S9 discharges brine, injects high-pressure hydrogen, seals for 48 hours, and then samples are taken to analyze the hydrogen sulfide content and calculate the elimination rate. Example 2

[0055] The method steps in this embodiment are basically the same as those in Embodiment 1, except that different hydrogen-producing and acid-producing bacteria are injected. Specifically, in S7, glycogen-producing anaerobic hydrogen-producing bacilli (CGMCC 1.5070) are inoculated onto the glycerol-polyacrylamide-glycerol ring, so that the hydrogen-producing microorganisms can carry out anaerobic fermentation using the glycerol in the glycerol-polyacrylamide-glycerol ring in the high-salt anaerobic environment of the salt cave. Comparative Example 1

[0056] The method and steps of this comparative example are basically the same as those of Example 1, except that the glycerol-polyacrylamide-glycerol layer was not constructed. That is, steps S1-6 are omitted, and in S7, Clostridium butyricum (MCCC 1A19159) is directly introduced into the salt cave with brine and cultured in a sealed static environment. Comparative Example 2

[0057] The method steps in this comparative example are basically the same as those in Example 1, except that brine containing polyacrylamide is not introduced, i.e., step S3 is omitted. Comparative Example 3

[0058] The method steps of this comparative example are basically the same as those of Example 1, except that oxygen-controlled air containing potassium persulfate mist is not introduced, i.e., step S4 is not included. Comparative Example 4

[0059] The method steps of this comparative example are basically the same as those of Example 1, except that a 15% glycerol solution is not introduced, i.e., step S5 is omitted. Comparative Example 5

[0060] The method steps in this comparative example are basically the same as those in Example 1, except that hydrogen-producing and acid-producing bacteria were not added, but halophilic hydrogen-metabolizing bacteria were added. Specifically, in S7, Methanobacterium flexile (CGMCC1.5092) was inoculated onto the glycerol-polyacrylamide-glycerol ring. Comparative Example 6

[0061] The method steps in this comparative example are basically the same as those in Example 1, except that: the addition of 20 μM molybdate solution from the central tube, i.e., real-time monitoring of parameters such as temperature, pH, hydrogen concentration, volatile acid concentration, and SRB activity in the salt cavern by S8, and the injection of glycerol into the salt cavern to promote the fermentation of the halophilic microorganisms and increase acid production when the volatile acid concentration is detected to decrease.

[0062] According to the construction methods of Examples 1-2 and Comparative Examples 1-6, the temperature, pH value, hydrogen sulfide content, and volatile acid concentration parameters within the salt cavern were monitored in real time. The blank group represents the content produced by the construction method without hydrogen sulfide suppression. Samples were taken and analyzed after 48 hours of sealing, and the elimination rate was calculated based on the hydrogen sulfide content. The changes are shown in Table 1.

[0063] Table 1. Changes in Hydrogen Sulfide

[0064] .

[0065] The changes in hydrogen sulfide content show that in Comparative Example 1, the lack of a glycerol-polyacrylamide-glycerol layer prevented the hydrogen-producing and acid-producing strains from utilizing glycerol for fermentation, resulting in a small difference in hydrogen sulfide content compared to the control, essentially eliminating it. In Comparative Example 2, the absence of brine containing polyacrylamide led to excessive fluidity of glycerol within the salt cavern; excess glycerol was discharged with the brine, resulting in a thin glycerol layer and fewer available fermentation reactants for microorganisms, thus reducing the inhibitory effect of volatile acids. In Comparative Example 3, the absence of oxygen-controlled air containing potassium persulfate mist resulted in weak binding between glycerol and polyacrylamide, leading to an unstable glycerol-polyacrylamide-glycerol layer. Similarly, the absence of a 15% glycerol solution in Comparative Example 4 also resulted in a thin layer. Neither Comparative Example 3 nor Comparative Example 4 constructed a stable glycerol-polyacrylamide-glycerol layer, leading to decreased hydrogen and acid production efficiency. Comparative Example 5, lacking hydrogen-producing and acid-producing bacteria and only adding halophilic methanobacteria, did not produce volatile acids that inhibit sulfate-reducing bacteria, thus failing to inhibit hydrogen sulfide production. Therefore, the elimination rate of hydrogen sulfide in Comparative Example 5 was the lowest among the other examples and comparative examples. Adding molybdate solution was a supplementary measure to suppress hydrogen sulfide from volatile acids. Comparative Example 6 did not add 20 μM molybdate solution from the central tube; therefore, its elimination rate without supplementary protection was 77.3%, which did not meet the requirement of 85%.

[0066] In Examples 1 and 2, hydrogen-producing and acid-producing bacteria were added for anaerobic fermentation in a stable glycerol-polyacrylamide-glycerol layer, with molybdate solution added as a supplement. The elimination rates were 91.9% and 88.7%, respectively. The glycerol-polyacrylamide-glycerol layer provides fermentation conditions for the hydrogen-producing and acid-producing bacteria and helps to isolate sulfate-reducing bacteria in the inner wall layer from hydrogen gas, preventing them from producing hydrogen sulfide. The inoculated microorganisms have hydrogen-producing and acid-producing characteristics, and through metabolism, they produce volatile fatty acids that inhibit the growth of sulfate-reducing bacteria (SRB) and hydrogen sulfide production within the salt cavern. Furthermore, in salt cavern hydrogen storage engineering, this method can both inhibit hydrogen sulfide and produce some hydrogen for storage.

[0067] Based on the embodiments of the present invention described above, and through the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for inhibiting sulfate-reducing bacteria in salt cavern hydrogen storage engineering, characterized in that, Includes the following steps: S1 mixes glycerol and brine to form glycerol solution I, which is then injected into the salt cavern through the central tube; S2 introduces dry air into the salt cavern through the production casing, while simultaneously discharging the glycerol solution; S3 injects the polyacrylamide solution from the central tube into the salt cavern; S4 introduces oxygen-controlled air containing potassium persulfate mist into the salt cavern from the production casing, while simultaneously discharging polyacrylamide solution. S5 then injects glycerol solution II from the central tube into the salt cavity; S6 employs a drying process to construct a glycerol-polyacrylamide-glycerol ring on the inner wall of the salt cave. S7 Inoculate the halophilic hydrogen-producing and acid-producing microorganisms onto the glycerol-polyacrylamide-glycerol ring; the halophilic hydrogen-producing and acid-producing microorganisms are Clostridium or Enterobacter strains capable of anaerobic fermentation and metabolism of glycerol to produce hydrogen and acid. S8 monitors the temperature, pH, hydrogen concentration, volatile acid concentration, and hydrogen sulfide concentration in the salt cavern in real time, and optimizes the fermentation environment of the microorganisms based on the monitoring data; when the volatile acid concentration decreases, glycerol is injected into the salt cavern; when the activity of sulfate-reducing bacteria shows an upward trend, sodium molybdate solution is added from the central tube. S9 injects high-pressure hydrogen and stores the hydrogen in a sealed environment.

2. The method according to claim 1, characterized in that, The glycerol solution I mentioned in step S1 has a mass fraction of 5%-10%.

3. The method according to claim 1, characterized in that, In step S2, dry air is introduced, and the gas flow rate is controlled to be 0.5-1 m / s.

4. The method according to claim 1, characterized in that, The polyacrylamide solution in step S3 has a mass fraction of 1%-2%, and the solvent is brine.

5. The method according to claim 1, characterized in that, The oxygen-controlled air containing potassium persulfate mist in step S4 has a potassium persulfate mist concentration of 0.3%-0.6%, an oxygen content of 1%-5% VOL, and an air flow rate of 0.5-1 m / s.

6. The method according to claim 1, characterized in that, The glycerol solution II mentioned in step S5 has a mass fraction of 15%-25%, and the solvent is brine.

7. The method according to claim 1, characterized in that, The drying process described in step S6 involves introducing dry nitrogen gas and controlling the nitrogen flow rate to be 0.5-1 m / s; the thickness of the glycerol-polyacrylamide-glycerol ring is 0.5-1 cm.

8. The method according to claim 1, characterized in that, The inoculation method described in step S7 is as follows: halophilic hydrogen-producing and acid-producing microorganisms are introduced into the salt cave with the brine and left to stand for 24 hours; then hydrogen gas is introduced through the production casing, and the brine is discharged, so that the microorganisms adhere to the glycerol-polyacrylamide-glycerol layer, and finally the cave is sealed for 48 hours for anaerobic culture.

9. The method according to claim 1, characterized in that, The method for optimizing the fermentation environment of microorganisms based on monitoring data in step S8 includes injecting glycerol and molybdate solution: when the volume fraction of volatile acid is detected to drop to 10 ppm, glycerol is injected into the salt cavern; when the inhibitory effect of glycerol on acid production reaches its extreme value, molybdate solution is added from the central tube.

10. The method according to claim 9, characterized in that, The concentration of the molybdate solution is 10-50 μmol / L.

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