Ship ballast water residual chlorine neutralization system and its dosing control method

Abstract

A method for controlling the dosing of a residual chlorine neutralization system for ship ballast water includes: S10: obtaining the holding time x of ballast water in the ballast tank; S20: calculating the total amount W and concentration C of the neutralizing agent based on the holding time x, and controlling the neutralizing agent dosing device to dispense the neutralizing agent according to the calculated total amount W and concentration C; S30: after the start of unloading, controlling the neutralizing agent dosing device to add neutralizing agent to the unloading pipeline; S40: detecting the current residual chlorine concentration T of the neutralized ballast water in the unloading pipeline, and comparing the current residual chlorine concentration T with a set value; if the current residual chlorine concentration T is greater than the set value, increasing the dosing flow rate of the neutralizing agent; if the current residual chlorine concentration T is less than the set value, decreasing the dosing flow rate of the neutralizing agent; S50: repeating step S40 until unloading is completed. This invention also provides a residual chlorine neutralization system for ship ballast water.

Description

Technical Field

[0001] This invention relates to the field of ship ballast water treatment technology, and in particular to a residual chlorine neutralization system for ship ballast water and its dosing control method. Background Technology

[0002] To control a ship's trim, length, draft, stability, or stress concentration, almost all ships are equipped with ballast tanks and additional ballast water is added according to the ship's actual cargo load to ensure navigation safety.

[0003] To kill bacteria and plankton in ballast water, active substances such as sodium hypochlorite are typically added to disinfect it. To prevent potential environmental risks to receiving water bodies from TRO (Total Residual Oxidant) during discharge, management systems using active substances to treat ballast water are required to be equipped with neutralization devices. These devices add neutralizing agents to the discharged water to neutralize residual chlorine. A residual chlorine detection device is installed outside the discharge hull to monitor the residual chlorine concentration in real time, ensuring it remains below 0.1 ppm.

[0004] Currently, the understanding of the decay pattern of residual chlorine concentration in electrolyzed seawater during ballast water discharge is not comprehensive enough, making it impossible to accurately predict the consumption and concentration of neutralizing agents. Excessive addition of neutralizing agents during ballast water discharge results in significant waste of these agents. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the dosing of neutralizing agents in a ship's ballast water residual chlorine neutralization system. This method can determine the total amount and concentration of neutralizing agents based on the actual holding time of the ballast water in the ballast tank, thereby greatly reducing the amount of neutralizing agents used and avoiding waste while ensuring the neutralization effect.

[0006] This invention provides a method for controlling the dosing of chemicals in a ship's ballast water residual chlorine neutralization system. The system includes a ballast tank, a discharge pipeline, and a neutralization dosing device. The discharge pipeline is connected to the ballast tank, and the neutralization dosing device is connected to the discharge pipeline. The device is used to add a neutralizing agent to the discharge pipeline. The dosing control method includes:

[0007] S10: Obtain the retention time x of the ballast water in the ballast tank;

[0008] S20: Based on the retention time x of the ballast water, calculate the total amount W and concentration C of the neutralizing agent in the neutralization dosing device, and control the neutralizing agent preparation of the neutralization dosing device according to the calculated total amount W and concentration C; the total amount W and concentration C satisfy the following conditions:

[0009] (1) When the retention time x of the ballast water is less than or equal to 15 days,

[0010] W=[a1*Sin(b1*x+c1)+a2*Sin(b2*x+c2)]*N;

[0011] C=[f1*Sin(g1*x+h1)+f2*Sin(g2*x+h2)] / 1000*Q*k;

[0012] (2) When the retention time x of the ballast water is greater than 15 days,

[0013] W=[d1*Exp(e1*x)+d2*Exp(e2*x)]*N;

[0014] C=[i1*Exp(j1*x)+i2*Exp(j2*x)] / 1000*Q*k;

[0015] Wherein, a1, b1, c1, a2, b2, c2, d1, e1, d2, e2, f1, g1, h1, f2, g2, h2, i1, j1, i2, and j2 are equation coefficients; N is the total ballast water discharged in the discharge pipeline; Q is the ballast water discharge flow rate in the discharge pipeline; and k is the dosing coefficient of the neutralization dosing device.

[0016] S30: After the discharge begins, control the neutralization dosing device to add neutralizing agent into the discharge pipeline according to the initial dosing flow rate M;

[0017] S40: Detect the current residual chlorine concentration T of the neutralized ballast water in the discharge pipeline, and compare the current residual chlorine concentration T with a set value; if the current residual chlorine concentration T is greater than the set value, increase the flow rate of the neutralizing agent; if the current residual chlorine concentration T is less than the set value, decrease the flow rate of the neutralizing agent.

[0018] S50: Repeat step S40 above until the loading is complete.

[0019] Furthermore, in step S20 above, the range of values ​​for the coefficients of each equation is as follows:

[0020] a1 is 264–304, b1 is 0.0005–0.0007, c1 is 2.58–2.98, a2 is 8.57–9.87, b2 is 0.018–0.021, c2 is 0.31–0.36, d1 is 65.09–74.00, e1 is -0.008–-0.010, d2 is 30.10–34.68, and e2 is -0.00018–-0.0002. 1. f1 is 527.42~607.68, g1 is 0.0005~0.0006, h1 is 2.58~2.98, f2 is 17.09~19.69, g2 is 0.018~0.021, h2 is 0.31~0.36, i1 is 183~210, j1 is -0.008~-0.01, i2 is 66~76, j2 is -0.00018~-0.00021;

[0021] Where W is in kg, x is in hours, and N is in meters. 3 The unit of C is kg / m³ 3 The unit of Q is m. 3 / h.

[0022] Furthermore, in step S40 above, the increase or decrease in the flow rate of the neutralizing agent each time does not exceed 20% of the previous flow rate.

[0023] Furthermore, in step S40 above, the amount of increase or decrease in the flow rate of the neutralizing agent each time is 10% of the previous flow rate.

[0024] Furthermore, in step S40 above, no upper limit is set on the actual maximum flow rate of the neutralizing agent during the loading process.

[0025] Furthermore, in step S40 above, when the flow rate of the neutralizing agent is reduced to less than or equal to the set minimum flow rate Mmin, the drug is continued to be added at the minimum flow rate Mmin; wherein the minimum flow rate Mmin is less than the initial flow rate M.

[0026] Furthermore, in step S40 above, while maintaining the minimum dosing flow rate Mmin, the current residual chlorine concentration T is continuously monitored. If the current residual chlorine concentration T is less than or equal to the set value, the dosing continues at the minimum dosing flow rate Mmin; if the current residual chlorine concentration T is greater than the set value, the dosing flow rate of the neutralizing agent is increased.

[0027] The present invention also provides a ship ballast water residual chlorine neutralization system and a dosing control method for the above-mentioned ship ballast water residual chlorine neutralization system. The ship ballast water residual chlorine neutralization system includes a ballast tank, a discharge pipeline, a neutralization dosing device, a residual chlorine detection device, a flow meter, a timer, and a controller.

[0028] The discharge pipeline is connected to the ballast tank. The neutralization dosing device and the residual chlorine detection device are sequentially connected to the discharge pipeline. The flow meter is installed on the discharge pipeline. The neutralization dosing device is used to add neutralizing agent to the discharge pipeline. The residual chlorine detection device is used to detect the residual chlorine concentration T of the neutralized ballast water in the discharge pipeline. The timer is used to record the holding time x of the ballast water in the ballast tank. The flow meter is used to detect the discharge flow rate Q of the ballast water in the discharge pipeline.

[0029] The timer, the neutralization dosing device, the flow meter, and the residual chlorine detection device are all electrically connected to the controller. The controller is used to calculate the total amount W and concentration C of the neutralizing agent in the neutralization dosing device based on the ballast water holding time x recorded by the timer, the total amount N of ballast water discharged in the discharge pipeline, and the discharge flow rate Q of ballast water in the discharge pipeline. The controller also controls the neutralization dosing device to prepare the neutralizing agent based on the calculated total amount W and concentration C, and controls the neutralization dosing device to add the neutralizing agent to the discharge pipeline.

[0030] Furthermore, the neutralization dosing device includes a neutralizing agent storage tank, a dosing pipeline, a dosing pump, a neutralizing agent supply device, and a fresh water supply device. One end of the dosing pipeline is connected to the neutralizing agent storage tank, and the other end of the dosing pipeline is connected to the discharge pipeline. The dosing pump is installed on the dosing pipeline. Both the neutralizing agent supply device and the fresh water supply device are connected to the neutralizing agent storage tank. The neutralizing agent supply device is used to add neutralizing agent to the neutralizing agent storage tank, and the fresh water supply device is used to add fresh water to the neutralizing agent storage tank. Both the neutralizing agent supply device and the fresh water supply device are electrically connected to the controller.

[0031] Furthermore, the dosing pump is a variable frequency pump, and the dosing pump is electrically connected to the controller; the controller is used to control the dosing flow rate of the dosing pump according to the residual chlorine concentration detected by the residual chlorine detection device.

[0032] The present invention provides a method for controlling the dosing of neutralizing agents in a ship's ballast water residual chlorine neutralization system. This method calculates the total amount W and concentration C of neutralizing agent in the neutralization dosing device based on the ballast water holding time x in the ballast tank, the total amount N of ballast water discharged from the ballast tank, and the discharge flow rate Q of the ballast water in the discharge pipeline. The neutralizing agent is then prepared accordingly. Simultaneously, during the discharge process, the current residual chlorine concentration T is compared with a set value to determine the neutralization effect, and the dosing flow rate of the neutralizing agent is adjusted accordingly. This allows the ship's ballast water residual chlorine neutralization system to dosing based on the actual amount of neutralizing agent required during the discharge process, thereby significantly reducing the amount of neutralizing agent used and avoiding waste while ensuring the neutralization effect. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the residual chlorine neutralization system for ship ballast water in an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating the relationship between the TRO concentration of ballast water and the retention time of ballast water in an embodiment of the present invention. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0036] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] The directional terms such as "up," "down," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this invention are defined by the position of the structures in the drawings and the relative positions of the structures, and are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed in this application.

[0038] like Figure 1 As shown, this embodiment of the invention provides a method for controlling the dosing of chemicals in a ship's ballast water residual chlorine neutralization system. The system includes a ballast tank 1, a discharge pipeline 2, and a neutralization dosing device 3. The discharge pipeline 2 is connected to the ballast tank 1, and the neutralization dosing device 3 is connected to the discharge pipeline 2. The neutralization dosing device 3 is used to add neutralizing agents to the discharge pipeline 2. The method for controlling the dosing of chemicals in this ship's ballast water residual chlorine neutralization system includes:

[0039] S10: Obtain the residence time x of the ballast water in ballast tank 1 (i.e., the residence time of the ballast water in ballast tank 1);

[0040] S20: Based on the ballast water retention time x, calculate the total amount W (i.e., the total consumption of neutralizing agent) and concentration C of the neutralization dosing device 3, and control the neutralization dosing device 3 to prepare the neutralizing agent according to the calculated total amount W and concentration C (i.e., the neutralization dosing device 3 prepares the neutralizing agent according to the calculated total amount W and concentration C); the total amount W and concentration C satisfy the following conditions:

[0041] (1) When the ballast water retention time x is less than or equal to 15 days,

[0042] W=[a1*Sin(b1*x+c1)+a2*Sin(b2*x+c2)]*N;

[0043] C=[f1*Sin(g1*x+h1)+f2*Sin(g2*x+h2)] / 1000*Q*k;

[0044] (2) When the ballast water retention time x is greater than 15 days,

[0045] W=[d1*Exp(e1*x)+d2*Exp(e2*x)]*N;

[0046] C=[i1*Exp(j1*x)+i2*Exp(j2*x)] / 1000*Q*k;

[0047] Where a1, b1, c1, a2, b2, c2, d1, e1, d2, e2, f1, g1, h1, f2, g2, h2, i1, j1, i2, and j2 are equation coefficients; N is the total amount of ballast water discharged from ballast tank 1 (i.e., the total amount of ballast water discharged from ballast tank 1; the value of N can be determined according to actual needs); Q is the discharge flow rate of ballast water in discharge pipeline 2; k is the dosing coefficient of neutralization dosing device 3 (this dosing coefficient k is related to the dosing flow rate of neutralization dosing device 3; specifically, C is negatively correlated with the dosing flow rate of neutralization dosing device 3, when the dosing flow rate of neutralization dosing device 3 is larger, C should be smaller; when the dosing flow rate of neutralization dosing device 3 is smaller, C should be larger; therefore, the value of k is determined according to the initial dosing flow rate set by neutralization dosing device 3).

[0048] S30: After the discharge begins, control the neutralization dosing device 3 to add neutralizing agent to the discharge pipeline 2 according to the initial dosing flow rate M;

[0049] S40: Detect the current residual chlorine concentration T of the neutralized ballast water in the discharge pipeline 2, and compare the current residual chlorine concentration T with the set value; if the current residual chlorine concentration T is greater than the set value, increase the flow rate of the neutralizing agent in the neutralization dosing device 3; if the current residual chlorine concentration T is less than the set value, decrease the flow rate of the neutralizing agent in the neutralization dosing device 3 (when the detected residual chlorine concentration T is exactly equal to the set value, the current dosing flow rate can be kept unchanged).

[0050] S50: Repeat step S40 above until the loading is complete.

[0051] Specifically, when using active substances such as sodium hypochlorite to treat the ballast water in ballast tank 1, the residual concentration (TRO concentration) of the active substances after reacting with harmful organisms in the ballast water is related to the salinity, temperature, dissolved oxygen, pH value of the ballast water, and the holding time x of the ballast water in ballast tank 1 (i.e., the reaction time between the active substances and harmful organisms in the ballast water). However, based on experimental results and actual operating conditions, considering that: 1. Changes in the salinity, temperature, dissolved oxygen, and pH value of the ballast water have a relatively small impact on the TRO concentration of the ballast water; 2. Ballast... The salinity, temperature, dissolved oxygen, and pH of the water do not change much during actual shipboard operations. When calculating the total amount W and concentration C of the neutralizing agent, the design margin is fully considered. Therefore, the relationship between the TRO concentration of the ballast water and the salinity, temperature, dissolved oxygen, pH, and the holding time x of the ballast water in ballast tank 1 can be simplified to the relationship between the TRO concentration of the ballast water and the holding time x of the ballast water in ballast tank 1. By combining mathematical statistics and curve fitting, the calculation formulas for the total amount W and concentration C of the neutralizing agent can be obtained.

[0052] At the same time, such as Figure 2 As shown, Figure 2 The figure illustrates the relationship between the TRO concentration of three groups of ballast water and the ballast water retention time x; where the horizontal axis represents the ballast water retention time x in days; and the vertical axis represents the ballast water TRO concentration in mg / L. Figure 2 As can be seen, the TRO concentration of the ballast water decreases with increasing ballast water retention time (x), and the rate of TRO concentration decay slows down over time. Based on actual engineering simulations, when the ballast water retention time (x) is less than or equal to 15 days, the relationship between TRO concentration and retention time (x) more closely resembles a sine function curve; while when the ballast water retention time (x) is greater than 15 days, the relationship between TRO concentration and retention time (x) more closely resembles an exponential function curve. This leads to the calculation formulas for the total amount W and concentration C of the neutralizing agent mentioned above.

[0053] The chemical dosing control method for the residual chlorine neutralization system of ship ballast water provided in this embodiment of the invention calculates the total amount W and concentration C of neutralizing agent in the neutralization dosing device 3 based on the ballast water holding time x in ballast tank 1, the total amount N of ballast water discharged from ballast tank 1, and the discharge flow rate Q of ballast water in discharge pipeline 2, and configures the neutralizing agent accordingly. Simultaneously, during the discharge process, the neutralization effect is determined by comparing the current residual chlorine concentration T with a set value, and the dosing flow rate of the neutralizing agent is adjusted accordingly. This allows the ship ballast water residual chlorine neutralization system to dosing according to the actual amount of neutralizing agent required during the discharge process, thereby greatly reducing the amount of neutralizing agent used while ensuring the neutralization effect and avoiding waste (based on the actual operation results of the ship, this dosing control method can save at least 30% of the neutralizing agent compared to existing dosing methods).

[0054] Furthermore, in this embodiment, the range of values ​​for the coefficients of each equation in step S20 above is as follows:

[0055] a1 is 264–304, b1 is 0.0005–0.0007, c1 is 2.58–2.98, a2 is 8.57–9.87, b2 is 0.018–0.021, c2 is 0.31–0.36, d1 is 65.09–74.00, e1 is -0.008–-0.010, d2 is 30.10–34.68, e2 is -0.00018–-0.00021, f1 is 527. The coefficients of each equation are calculated based on actual data. The values ​​for W are 0.42–607.68, g1 is 0.0005–0.0006, h1 is 2.58–2.98, f2 is 17.09–19.69, g2 is 0.018–0.021, h2 is 0.31–0.36, i1 is 183–210, j1 is -0.008–-0.01, i2 is 66–76, and j2 is -0.00018–-0.00021. W is in kg, x is in hours, and N is in m. 3 The unit of C is kg / m³ 3 The unit of Q is m. 3 / h. The coefficients in the above equations only indicate the relative proportional relationship between the coefficients; any proportional scaling between the coefficients should be covered within the scope of protection of this invention.

[0056] Furthermore, in this embodiment, in step S40 above, the increase or decrease in the flow rate of the neutralizing agent each time does not exceed 20% of the previous flow rate (for example, if the previous flow rate was 10L / h, then the adjustment range of the flow rate does not exceed 2L / h), thereby avoiding excessive adjustment of the flow rate each time and causing frequent fluctuations in the system. At the same time, it is beneficial for the system to adjust to a flow rate suitable for the current operating conditions during the dosing process.

[0057] Furthermore, in this embodiment, in the above S40 step, the amount of increase or decrease in the flow rate of the neutralizing agent each time is 10% of the previous flow rate.

[0058] Furthermore, in this embodiment, in step S40 above, when the flow rate of the neutralizing agent decreases to less than or equal to the set minimum flow rate Mmin, the dosing is maintained at the minimum flow rate Mmin (i.e., when the calculated flow rate is less than or equal to the minimum flow rate Mmin, dosing is performed at the minimum flow rate Mmin); wherein, the minimum flow rate Mmin is less than the initial flow rate M, and the minimum flow rate Mmin can be 0.6-0.9 times the initial flow rate M. Therefore, this reduces the amount of neutralizing agent used and avoids frequent system fluctuations, which is beneficial for maintaining system stability.

[0059] In step S40 above, while maintaining the minimum dosing flow rate Mmin, the current residual chlorine concentration T is continuously monitored. If the current residual chlorine concentration T is less than or equal to the set value, the dosing continues at the minimum dosing flow rate Mmin; if the current residual chlorine concentration T is greater than the set value, the dosing flow rate of the neutralizing agent is increased. This prevents the residual chlorine concentration from exceeding the standard during ballast water discharge.

[0060] Furthermore, in this embodiment, in step S40 above, the actual maximum flow rate of the neutralizing agent during the loading process is not set with an upper limit. That is, during the dosing process, the actual maximum flow rate is not set with an upper limit, and the actual minimum flow rate is executed according to the minimum flow rate Mmin (the actual minimum flow rate may be greater than the set minimum flow rate Mmin).

[0061] Furthermore, in this embodiment, the set value in step S40 above can be 0.1 ppm, that is, during the discharge process, the residual chlorine concentration of the ballast water does not exceed 0.1 ppm.

[0062] Furthermore, in this embodiment, in step S40 above, the interval between each detection of residual chlorine concentration can be set to 2 minutes.

[0063] like Figure 1 As shown, this embodiment of the invention also provides a ship ballast water residual chlorine neutralization system, and a dosing control method for the aforementioned ship ballast water residual chlorine neutralization system. The ship ballast water residual chlorine neutralization system includes a ballast tank 1, a discharge pipeline 2, a neutralization dosing device 3, a residual chlorine detection device 4, a flow meter 5, a timer 6, and a controller 7. The controller 7 is a PLC control device.

[0064] Ballast tank 1 is used to temporarily store ballast water. Discharge pipeline 2 is connected to ballast tank 1, allowing the ballast water in ballast tank 1 to be discharged to the ship's side via discharge pipeline 2. Neutralization dosing device 3 and residual chlorine detection device 4 are sequentially connected to discharge pipeline 2, with residual chlorine detection device 4 connected downstream of neutralization dosing device 3. Flow meter 5 is installed on discharge pipeline 2. Neutralization dosing device 3 adds neutralizing agent to discharge pipeline 2. Residual chlorine detection device 4 detects the residual chlorine concentration T of the neutralized ballast water in discharge pipeline 2. Timer 6 records the holding time x of the ballast water in ballast tank 1 (i.e., the time from the end of each ballasting process to the start of the next discharge). Flow meter 5 detects the discharge flow rate Q of the ballast water in discharge pipeline 2. Timer 6 can be a built-in timing device of controller 7 or an external timing device.

[0065] The timer 6, neutralization dosing device 3, flow meter 5, and residual chlorine detection device 4 are all electrically connected to the controller 7. The controller 7 is used to calculate the total amount W and concentration C of the neutralizing agent in the neutralization dosing device 3 based on the ballast water holding time x recorded by the timer 6, the total amount N of ballast water discharged from the ballast tank 1, and the discharge flow rate Q of the ballast water in the discharge pipeline 2. Based on the calculated total amount W and concentration C, the controller 7 controls the neutralization dosing device 3 to prepare the neutralizing agent and to add the neutralizing agent into the discharge pipeline 2.

[0066] Furthermore, such as Figure 1 As shown, in this embodiment, the neutralization dosing device 3 includes a neutralization agent storage tank 31 for storing neutralizing agents, a dosing pipeline 32, a dosing pump 33, a neutralizing agent supply device 34, and a fresh water supply device 35. One end of the dosing pipeline 32 is connected to the neutralizing agent storage tank 31, and the other end of the dosing pipeline 32 is connected to the discharge pipeline 2. The dosing pump 33 is installed on the dosing pipeline 32. The neutralizing agent supply device 34 and the fresh water supply device 35 are both connected to the neutralizing agent storage tank 31. The neutralizing agent supply device 34 is used to add neutralizing agent to the neutralizing agent storage tank 31, and the fresh water supply device 35 is used to add fresh water to the neutralizing agent storage tank 31 (specifically, the neutralizing agent supply device 34 and the fresh water supply device 35 can be a combination of a storage tank and a pump; of course, other supply methods can also be used). The neutralizing agent and fresh water mix in the neutralizing agent storage tank 31 to generate a neutralizing agent. Both the neutralizing agent supply device 34 and the fresh water supply device 35 are electrically connected to the controller 7. The controller 7 controls the total amount W and concentration C of the neutralizing agent in the neutralizing agent storage tank 31 by controlling the amount of neutralizing agent added by the neutralizing agent supply device 34 and the amount of fresh water added by the fresh water supply device 35.

[0067] Furthermore, such as Figure 1As shown, in this embodiment, the dosing pump 33 is a variable frequency pump, which allows for adjustment of its dosing flow rate. The dosing pump 33 is electrically connected to the controller 7, which controls the dosing flow rate of the dosing pump 33 based on the residual chlorine concentration detected by the residual chlorine detection device 4.

[0068] Furthermore, such as Figure 1 As shown, in this embodiment, a discharge pump 8 is installed on the discharge pipeline 2. The neutralization dosing device 3 is connected to the discharge pipeline 2 between the ballast tank 1 and the inlet of the discharge pump 8. The residual chlorine detection device 4 is connected to the discharge pipeline 2 after the outlet of the discharge pump 8. The neutralizing agent added by the neutralization dosing device 3 can not only mix and react with the ballast water in the discharge pipeline 2 in the pipeline, but can also be further mixed by the discharge pump 8, thereby improving the neutralization reaction rate.

[0069] The chemical dosing control method for the residual chlorine neutralization system of ship ballast water provided in this embodiment of the invention calculates the total amount W and concentration C of neutralizing agent in the neutralization dosing device 3 based on the ballast water holding time x in ballast tank 1, the total amount N of ballast water discharged from ballast tank 1, and the discharge flow rate Q of ballast water in discharge pipeline 2, and configures the neutralizing agent accordingly. Simultaneously, during the discharge process, the neutralization effect is determined by comparing the current residual chlorine concentration T with a set value, and the dosing flow rate of the neutralizing agent is adjusted accordingly. This allows the ship ballast water residual chlorine neutralization system to dosing according to the actual amount of neutralizing agent required during the discharge process, thereby greatly reducing the amount of neutralizing agent used while ensuring the neutralization effect and avoiding waste (based on the actual operation results of the ship, this dosing control method can save at least 30% of the neutralizing agent compared to existing dosing methods).

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling the addition of chemicals in a ship's ballast water residual chlorine neutralization system, the system comprising a ballast tank, a discharge pipeline, and a neutralization dosing device, wherein the discharge pipeline is connected to the ballast tank, the neutralization dosing device is connected to the discharge pipeline, and the neutralization dosing device is used to add a neutralizing agent to the discharge pipeline; characterized in that, The dosing control method includes: S10: Obtain the retention time x of the ballast water in the ballast tank; S20: Based on the retention time x of the ballast water, calculate the total amount W and concentration C of the neutralizing agent in the neutralization dosing device, and control the neutralizing agent preparation of the neutralization dosing device according to the calculated total amount W and concentration C; the total amount W and concentration C satisfy the following conditions: (1) When the retention time x of the ballast water is less than or equal to 15 days, W=[a1*Sin(b1*x+c1) + a2*Sin(b2*x+c2)]*N; C=[f1*Sin(g1*x+h1) + f2*Sin(g2*x+h2)] / 1000*Q*k; (2) When the retention time x of the ballast water is greater than 15 days, W=[d1* Exp (e1*x) + d2* Exp (e2*x) ]*N; C=[i1*Exp(j1*x) + i2*Exp (j2*x) ] / 1000*Q*k; Wherein, a1, b1, c1, a2, b2, c2, d1, e1, d2, e2, f1, g1, h1, f2, g2, h2, i1, j1, i2, and j2 are equation coefficients; N is the total discharge volume of ballast water in the ballast tank; Q is the discharge flow rate of ballast water in the discharge pipeline; k is the dosing coefficient of the neutralization dosing device; the value ranges of each equation coefficient are: a1 = 264~304, b1 = 0.0005~0.0007, c1 = 2.58~2.98, a2 = 8.57~9.87, b2 = 0.018~0.021, c2 = 0.31~0.36, d1 = 65.09~74.00, e1 = -0.008~-0.010, d2 is 30.10~34.68, e2 is -0.00018~-0.00021, f1 is 527.42~607.68, g1 is 0.0005~0.0006, h1 is 2.58~2.98, f2 is 17.09~19.69, g2 is 0.018~0.021, h2 is 0.31~0.36, i1 is 183~210, j1 is -0.008~-0.01, i2 is 66~76, j2 is -0.00018~-0.00021; where W is in kg, x is in hours, N is in m³, C is in kg / m³, and Q is in m³ / h; S30: After the discharge begins, control the neutralization dosing device to add neutralizing agent into the discharge pipeline according to the initial dosing flow rate M; S40: Detect the current residual chlorine concentration T of the neutralized ballast water in the discharge pipeline, and compare the current residual chlorine concentration T with a set value; if the current residual chlorine concentration T is greater than the set value, increase the flow rate of the neutralizing agent; if the current residual chlorine concentration T is less than the set value, decrease the flow rate of the neutralizing agent. S50: Repeat step S40 above until the loading is complete.

2. The dosing control method for the residual chlorine neutralization system of ship ballast water as described in claim 1, characterized in that, In step S40 above, the increase or decrease in the flow rate of the neutralizing agent each time shall not exceed 20% of the previous flow rate.

3. The dosing control method for the residual chlorine neutralization system of ship ballast water as described in claim 2, characterized in that, In step S40 above, the amount of increase or decrease in the flow rate of the neutralizing agent each time is 10% of the previous flow rate.

4. The dosing control method for the residual chlorine neutralization system of ship ballast water as described in claim 1, characterized in that, In step S40 above, when the flow rate of the neutralizing agent is reduced to less than or equal to the set minimum flow rate Mmin, the agent is continued to be added at the minimum flow rate Mmin; wherein the minimum flow rate Mmin is less than the initial flow rate M.

5. The dosing control method for the residual chlorine neutralization system of ship ballast water as described in claim 4, characterized in that, In step S40 above, while maintaining the minimum dosing flow rate Mmin, the current residual chlorine concentration T is continuously monitored. If the current residual chlorine concentration T is less than or equal to the set value, the dosing continues at the minimum dosing flow rate Mmin; if the current residual chlorine concentration T is greater than the set value, the dosing flow rate of the neutralizing agent is increased.

6. A residual chlorine neutralization system for ship ballast water, characterized in that, A method for controlling the dosing of chemicals in a ship ballast water residual chlorine neutralization system as described in any one of claims 1-5, wherein the ship ballast water residual chlorine neutralization system includes a ballast tank, a discharge pipeline, a neutralization dosing device, a residual chlorine detection device, a flow meter, a timer, and a controller; The discharge pipeline is connected to the ballast tank. The neutralization dosing device and the residual chlorine detection device are sequentially connected to the discharge pipeline. The flow meter is installed on the discharge pipeline. The neutralization dosing device is used to add neutralizing agent to the discharge pipeline. The residual chlorine detection device is used to detect the residual chlorine concentration T of the neutralized ballast water in the discharge pipeline. The timer is used to record the holding time x of the ballast water in the ballast tank. The flow meter is used to detect the discharge flow rate Q of the ballast water in the discharge pipeline. The timer, the neutralization dosing device, the flow meter, and the residual chlorine detection device are all electrically connected to the controller. The controller is used to calculate the total amount W and concentration C of the neutralizing agent in the neutralization dosing device based on the ballast water holding time x recorded by the timer, the total amount N of ballast water discharged from the ballast tank, and the discharge flow rate Q of ballast water in the discharge pipeline. The controller also controls the neutralization dosing device to prepare the neutralizing agent based on the calculated total amount W and concentration C, and controls the neutralization dosing device to add the neutralizing agent to the discharge pipeline.

7. The ship ballast water residual chlorine neutralization system as described in claim 6, characterized in that, The neutralization dosing device includes a neutralizing agent storage tank, a dosing pipeline, a dosing pump, a neutralizing agent supply device, and a fresh water supply device. One end of the dosing pipeline is connected to the neutralizing agent storage tank, and the other end is connected to the discharge pipeline. The dosing pump is installed on the dosing pipeline. Both the neutralizing agent supply device and the fresh water supply device are connected to the neutralizing agent storage tank. The neutralizing agent supply device is used to add neutralizing agent to the neutralizing agent storage tank, and the fresh water supply device is used to add fresh water to the neutralizing agent storage tank. Both the neutralizing agent supply device and the fresh water supply device are electrically connected to the controller.

8. The ship ballast water residual chlorine neutralization system as described in claim 7, characterized in that, The dosing pump is a variable frequency pump, and the dosing pump is electrically connected to the controller; the controller is used to control the dosing flow rate of the dosing pump according to the residual chlorine concentration detected by the residual chlorine detection device.

Images