Pre-film corrosion inhibition process by controlling initial concentration in ozone water treatment system

Abstract

The present invention relates to a process for pre-filming and corrosion inhibition in an ozone water treatment system by controlling an initial concentration, comprising the following steps: S1, before ozone water treatment, first performing ozone pre-filming treatment at a relatively low ozone concentration on a carbon steel pipeline, and monitoring the relatively low ozone concentration to stabilize it within a set range; installing a carbon steel hanging plate in a hanging plate rack for observing the pre-filming and corrosion inhibition effects, and observing the corrosion of the hanging plates made of the same material as the pipeline; during the ozone pre-filming treatment, the ozone water flowing through the pipeline normally enters the next process of the water treatment cycle of the ozone water treatment system; S2, after completing the pre-filming treatment, increasing the ozone concentration to perform ozone water treatment at a relatively high ozone concentration; S3, while performing the ozone water treatment, monitoring the relatively high ozone concentration in real time to stabilize it within another set range; and simultaneously observing the corrosion of the hanging plates made of the same material as the pipeline; if the corrosion exceeds the standard, returning to step S1.

Description

Technical Field

[0001] The invention relates to an ozone water treatment system, and in particular to a pre-film corrosion inhibition process by controlling initial concentration in the ozone water treatment system. Background Art

[0002] In industrial production, anti-corrosion coatings and pre-coatings are commonly used to control corrosion of carbon steel. Pre-coating for metal pipes typically involves injecting a corrosion inhibitor into the pipe, forming a dense, highly adhesive film on the inner wall, which provides a strong corrosion inhibition effect.

[0003] Ozone technology is widely used in water treatment, such as sterilization, deodorization, decolorization, oxidation, etc. It is also used in the scale inhibition, corrosion inhibition, sterilization and algae removal of circulating water.

[0004] However, there are few reports and applications of ozone pre-filming in related application processes.

[0005] In the ozone treatment circulating water treatment system, the make-up water pretreatment pipeline and the circulating water pipeline are the main injection points of concentrated ozone water. The problem of local excessive ozone concentration and corrosion is prone to occur here. In the renovation project, the injection port pipeline is an existing pipeline, and its material is mostly carbon steel. Carbon steel is relatively prone to corrosion, especially in a water environment with corrosive factors.

[0006] In order to reduce pipeline damage and extend its life in this application, some people have tried replacing the pipes near the injection port. However, the replacement length is difficult to accurately determine due to the uncertainty of water flow velocity and turbulence. Another option is to use corrosion inhibitors for pre-coating. However, for pipeline systems with water flow rates exceeding several thousand cubic meters per hour, or even tens of thousands of cubic meters per hour, the consumption of pre-coating agents is extremely high and it is easy to cause chemical pollution. At the same time, production must be stopped for pre-coating. In addition, many factories do not have the conditions for using corrosion inhibitors for pre-coating. Summary of the Invention

[0007] The purpose of the present invention is to provide a set of pre-film corrosion inhibition technology in ozone water treatment system by controlling the initial concentration, using ozone technology to treat circulating water while pre-filming the relevant carbon steel pipelines for corrosion inhibition.

[0008] The present invention adopts the following technical solutions:

[0009] A process for pre-film corrosion inhibition by controlling the initial concentration in an ozone water treatment system comprises the following steps:

[0010] S1. Before ozone water treatment, the carbon steel pipeline is first subjected to ozone pre-filming treatment at a relatively low ozone concentration, and the relatively low ozone concentration is monitored to stabilize it within a set range. Simultaneously, a bypass pipeline is opened on the ozone pre-filming pipeline and a coupon rack is installed. The ozone water during the pre-filming period is introduced into the coupon rack. Carbon steel coupons are installed in the coupon rack to observe the pre-filming and corrosion inhibition effects, and thus the corrosion of coupons made of the same material as the pipeline is observed. During the ozone pre-filming treatment period, the ozone water flowing through the pipeline normally enters the next process of the water treatment cycle of the ozone water treatment system.

[0011] S2. After completing the pre-film treatment, increase the ozone concentration and perform ozone water treatment at a higher ozone concentration;

[0012] S3. While the ozone water treatment is being carried out, the higher ozone concentration is monitored in real time to stabilize it within another set range; at the same time, the corrosion of the hanging piece of the same material as the pipeline is observed; if the corrosion exceeds the standard, return to step S1.

[0013] Preferably, the ozone water treatment system is provided with: an ozone concentration online monitoring device, a water pump, a flow meter, a hanging plate rack and a carbon steel hanging plate arranged thereon, and a control system.

[0014] Preferably, in step S1, during the pre-filming period, for the main pipeline of the make-up water pretreatment system and the circulating water main pipeline injected with concentrated ozone water, the ozone generation amount (M: kg / h) is adjusted and the diverted ozone flow rate (Q1: L / min) is controlled so that the ozone concentration (C: mg / L) in multiple target carbon steel pipelines meets the set value A; a transparent hanging rack is required to facilitate the observation of the corrosion of hanging plates of the same material as the pipeline during the pre-filming process; because the ozone consumption rate changes during the ozone pre-filming process, the above-mentioned set value A is not a fixed value during the pre-filming process, and is adjusted according to the time period gradient, wherein:

[0015] In the first step, the A value was set to 0.05-0.1 mg / L for 5 days;

[0016] The second step is to increase the A value to 0.2 mg / L for 1 day, during which the morphology of the hanging pieces in the hanging piece rack is observed;

[0017] In the third step, if there is no obvious corrosion aggravation of the coupon during the second step, the A value remains unchanged and the one-week pre-coating is terminated after one day. If the corrosion of the coupon is aggravated during the second step, the A value is reduced to 0.1±0.02 mg / L, maintained at this concentration for three days, and then increased to 0.2 mg / L again, continued for one day, and the pre-coating is terminated.

[0018] During the implementation of the above three steps, due to the fluctuation of the water injection volume of the main pipe, the ozone concentration online monitoring device and control system are used to adjust the ozone generation amount and ozone diversion flow rate so that the ozone concentration in the pipeline is maintained at the corresponding set value.

[0019] Furthermore, in step S2, after the ozone pre-film treatment is completed, the ozone concentrations in the make-up water pretreatment system and the circulating water main are adjusted respectively: the ozone dosage in the make-up water is increased to enhance the sterilization and algae removal effect of the source water; the ozone dosage in the circulating water main is maintained or reduced, and the ozone concentration in the main is dynamically adjusted according to the water quality and water volume after the front-end pretreatment and the water quality of the circulating water to maintain it at the design value, thereby achieving a dynamic balance between scale inhibition and corrosion inhibition.

[0020] Furthermore, in step S3, pre-film coupons are regularly placed on carbon steel pipelines through which ozone water with a concentration exceeding 0.1 mg / L flows to monitor corrosion risks and conduct corrosion rate tests regularly to reduce corrosion risks.

[0021] The beneficial effects of the present invention are:

[0022] 1) Provide a set of pre-film corrosion inhibition technology in ozone water treatment system by controlling the initial concentration, using ozone technology to treat circulating water while pre-filming the relevant carbon steel pipelines for corrosion inhibition;

[0023] 2) Through experimental verification, a set of effective pre-filming corrosion inhibition process steps is provided. During this process, different A values ​​are monitored to achieve the effect of ozone pre-filming corrosion inhibition and to enable ozone pre-filming treatment and oxygen water treatment to be carried out simultaneously to complement each other;

[0024] 3) Ozone pre-filming is uniform, which completely solves the problem of pipeline corrosion caused by excessive local ozone concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the process of pre-film corrosion inhibition by controlling the initial concentration in the ozone water treatment system of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0027] Prior art has not yet demonstrated a water treatment process that utilizes ozone pre-filming followed by elevated ozone concentrations (which are considered corrosive to metals in water treatment engineering). This is primarily because the concentration and duration used in ozone pre-filming are not commonly accepted within the industry. Furthermore, the pre-filming process is not a simple one-step process; it requires a fixed set of steps. This process was ultimately finalized by the author after numerous trials, failed experiments, and creative process adjustments.

[0028] During the ozone treatment of circulating water, a large number of carbon steel pipes come into contact with concentrated ozone water. To reduce the corrosion risk of these pipes, this embodiment utilizes existing ozone technology to pre-coat them and enhance their corrosion resistance. Specifically, a high-concentration ozone pre-coating corrosion inhibition process is designed. This utilizes ozone technology to pre-coat the relevant carbon steel pipes while simultaneously treating the circulating water.

[0029] like Figure 1 As shown: A process for pre-film corrosion inhibition by controlling the initial concentration in an ozone water treatment system includes the following steps:

[0030] Step S1: Before ozone water treatment, the carbon steel pipeline is first subjected to ozone pre-filming treatment at a relatively low ozone concentration, and the relatively low ozone concentration is monitored to stabilize it within a set range. Simultaneously, a bypass pipeline is opened on the ozone pre-filming pipeline and a coupon rack is installed. The ozone water during the pre-filming period is introduced into the coupon rack. Carbon steel coupons are installed in the coupon rack to observe the pre-filming and corrosion inhibition effects, and thereby observe the corrosion of coupons made of the same material as the pipeline. During the ozone pre-filming treatment period, the ozone water flowing through the pipeline normally enters the next process of the water treatment cycle of the ozone water treatment system.

[0031] Specifically, during the pre-filming period, for the main pipeline of the make-up water pretreatment system and the circulating water main pipeline injected with concentrated ozone water, the ozone generation amount (M: kg / h) and the diverted ozone flow rate (Q1: L / min) are adjusted to ensure that the ozone concentration (C: mg / L) in multiple target carbon steel pipelines meets the set value A. During the pre-filming process, a transparent hanging rack is required to facilitate the observation of the corrosion of hanging pieces of the same material as the pipeline. Because the ozone consumption rate changes during the ozone pre-filming process, the above-mentioned set value A is not a fixed value during the pre-filming process, and is adjusted according to the time period gradient, where:

[0032] In the first step, the A value was set to 0.05-0.1 mg / L for 5 days;

[0033] The second step is to increase the A value to 0.2 mg / L for 1 day, during which the morphology of the hanging pieces in the hanging piece rack is observed;

[0034] In the third step, if there is no obvious corrosion aggravation of the coupon during the second step, the A value remains unchanged and the one-week pre-coating is terminated after one day. If the corrosion of the coupon is aggravated during the second step, the A value is reduced to 0.1±0.02 mg / L, maintained at this concentration for three days, and then increased to 0.2 mg / L again, continued for one day, and the pre-coating is terminated.

[0035] During the implementation of the above three steps, due to the fluctuation of the water injection volume of the main pipe, the ozone concentration online monitoring device and control system are used to adjust the ozone generation amount and ozone diversion flow rate so that the ozone concentration in the pipeline is maintained at the corresponding set value.

[0036] Step S2: After the pre-film treatment is completed, the ozone concentration is increased to perform ozone water treatment at a higher ozone concentration; specifically, after the ozone pre-film treatment is completed, the ozone concentrations in the make-up water pretreatment system and the circulating water main are adjusted respectively: the ozone dosage in the make-up water is increased to enhance the sterilization and algae removal effect of the source water; the ozone dosage in the circulating water main is maintained or reduced, and the ozone concentration in the main is dynamically adjusted according to the water quality and water volume after the front-end pretreatment and the water quality of the circulating water to maintain it at the design value, thereby achieving a dynamic balance between scale inhibition and corrosion inhibition.

[0037] Step S3: While the ozone water treatment is being carried out, the higher ozone concentration is monitored in real time to stabilize it within another set range; at the same time, the corrosion of the coupons made of the same material as the pipeline is observed; if the corrosion exceeds the standard, the process returns to step S1; in this step S3, pre-filmed coupons are regularly placed on the carbon steel pipelines through which ozone water with a concentration exceeding 0.1 mg / L flows to monitor the corrosion risk, and corrosion rate tests are regularly performed to reduce the corrosion risk.

[0038] In this embodiment, the ozone water treatment system is provided with: an ozone concentration online monitoring device, a water pump, a flow meter, a hanging plate rack and a carbon steel hanging plate arranged thereon, and a control system.

[0039] In summary, the present invention provides a set of pre-filming corrosion inhibition processes in an ozone water treatment system by controlling the initial concentration, and utilizes ozone technology to pre-film corrosion inhibition on related carbon steel pipelines while treating circulating water; through experimental verification, a set of effective process steps for pre-filming corrosion inhibition is provided, and during this process, different A values ​​are monitored to achieve the effect of ozone pre-filming corrosion inhibition and to enable the ozone pre-filming treatment to be carried out simultaneously with the oxygen water treatment to complement each other; the ozone pre-filming is uniform, which completely solves the problem of pipeline corrosion caused by excessively high local ozone concentrations.

[0040] The above are preferred embodiments of the present invention. Those skilled in the art may make various changes or improvements based on the above. Without departing from the overall concept of the present invention, these changes or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A process for pre-film corrosion inhibition by controlling the initial concentration in an ozone water treatment system, characterized in that: The following steps are involved: S1. Before ozone water treatment, the carbon steel pipeline is first subjected to ozone pre-coating treatment with a relatively low ozone concentration, and the relatively low ozone concentration is monitored to stabilize it within a set range. Simultaneously, a bypass pipe is opened on the ozone pre-coating pipeline and a coupon rack is installed. The ozone water during the pre-coating period is introduced into the coupon rack. Carbon steel coupons are installed in the coupon rack to observe the pre-coating and corrosion inhibition effects, and the corrosion condition of the coupons made of the same material as the pipeline is observed accordingly. During the ozone pre-film treatment, the ozone water flowing through the pipeline normally enters the next process of the water treatment cycle of the ozone water treatment system; S2. After completing the pre-film treatment, increase the ozone concentration and perform ozone water treatment at a higher ozone concentration; S3. While the ozone water treatment is being carried out, the higher ozone concentration is monitored in real time to stabilize it within another set range; at the same time, the corrosion of the hanging piece of the same material as the pipeline is observed; If the corrosion exceeds the standard, return to step S1.

2. The process for pre-film corrosion inhibition by controlling the initial concentration in the ozone water treatment system according to claim 1, characterized in that: The ozone water treatment system is provided with: an ozone concentration online monitoring device, a water pump, a flow meter, a hanging plate rack and a carbon steel hanging plate arranged thereon, and a control system.

3. The process of pre-film corrosion inhibition by controlling initial concentration in the ozone water treatment system according to claim 1, characterized in that: In step S1, during the pre-filming period, for the main pipeline of the make-up water pretreatment system and the circulating water main pipeline injected with concentrated ozone water, the ozone generation amount is adjusted and the diverted ozone flow rate is controlled so that the ozone concentration in multiple target carbon steel pipelines meets the set value A. During the pre-filming process, a transparent hanging rack is required to facilitate the observation of the corrosion of hanging plates made of the same material as the pipeline. Because the ozone consumption rate changes during the ozone pre-filming process, the set value A is not a fixed value during the pre-filming process, and is adjusted according to a time period gradient, wherein: In the first step, the A value was set to 0.05-0.1 mg / L for 5 days; The second step is to increase the A value to 0.2 mg / L for 1 day, during which the morphology of the hanging pieces in the hanging piece rack is observed; In the third step, if there is no obvious corrosion aggravation of the coupon during the second step, the A value remains unchanged and the one-week pre-coating is terminated after one day. If the corrosion of the coupon is aggravated during the second step, the A value is reduced to 0.1±0.02 mg / L, maintained at this concentration for three days, and then increased to 0.2 mg / L again, continued for one day, and the pre-coating is terminated. During the implementation of the above three steps, due to the fluctuation of the water injection volume of the main pipe, the ozone concentration online monitoring device and control system are used to adjust the ozone generation amount and ozone diversion flow rate so that the ozone concentration in the pipeline is maintained at the corresponding set value.

4. The process for pre-film corrosion inhibition by controlling the initial concentration in the ozone water treatment system according to claim 3, characterized in that: In step S2, after the ozone pre-film treatment is completed, the ozone concentrations in the make-up water pretreatment system and the circulating water main are adjusted respectively: the ozone dosage in the make-up water is increased to enhance the sterilization and algae removal effect of the source water; the ozone dosage in the circulating water main is maintained or reduced, and the ozone concentration in the main is dynamically adjusted according to the water quality and water volume after the front-end pretreatment and the water quality of the circulating water to maintain it at the design value, thereby achieving a dynamic balance between scale inhibition and corrosion inhibition.

5. The process for pre-film corrosion inhibition by controlling initial concentration in the ozone water treatment system according to claim 4, characterized in that: In step S3, pre-filmed coupons are placed regularly on carbon steel pipelines through which ozone water with a concentration exceeding 0.1 mg / L flows, and corrosion risk monitoring is performed. Corrosion rate testing is also performed regularly to reduce corrosion risk.

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