Multi-sensor online detection system for tank washing wastewater of chemical tanker

Abstract

The invention discloses a chemical tanker tank washing wastewater multi-sensor online detection system, which belongs to the field of chemical tanker cargo transportation and comprises a water supply tank washing pump, a water drainage tank washing pump, a primary detection system, a fine and accurate measurement system and a detection data processing and analysis system. By designing a primary detection system and a fine detection system, the fine detection system is automatically put into operation after the primary detection is qualified, so that the detection precision is improved, the working time of the gas chromatograph for fine detection is shortened, and the service life of the gas chromatograph for the fine detection equipment is prolonged. And a plurality of throttle valves and sampling pools are designed in the system, so that a buffering effect is achieved to prevent the flow velocity and pressure fluctuation of the to-be-detected liquid, the to-be-detected samples can be uniformly mixed, and the stability and the detection precision of the system are improved.

Description

Technical Field

[0001] The invention belongs to the field of chemical tanker cargo transportation, and in particular relates to a multi-sensor online detection system for tank washing wastewater of a chemical tanker. Background Art

[0002] Before loading cargo on a chemical tanker, the cleanliness of the cargo hold must be inspected by a commodity inspection agency. Only when the inspection results are qualified can cargo be loaded. Therefore, the effectiveness of tank cleaning directly determines whether the ship can successfully load the cargo specified in the contract. At present, the tank cleaning operation of chemical tankers mainly relies on the personal experience of the crew, and there is a lack of an online detection system to determine whether the tank cleaning meets the qualified standards. This leads to the problem of excessive cleaning during the tank cleaning process, resulting in water and electricity waste. For cargoes such as ethylene glycol, diethylene glycol, acetone, and methanol that have higher tank cleaning requirements, bulkhead tests are also required. If the bulkhead test or tank inspection fails, the ship will not be able to meet the loading conditions, which will in turn cause economic losses to the shipping company such as ship delays and breach of charter contracts.

[0003] According to their chemical properties, chemicals can be divided into basic categories such as ketones, alcohols, lipids, hydrocarbons and ethers. Due to differences in molecular structure, chemicals of the same category can also derive into a variety of different substances, such as alcohols including methanol and ethanol. The different physical properties of these chemicals make the tank cleaning process complicated, and different tank cleaning methods need to be adopted, such as hot and cold seawater washing, hot and cold fresh water washing and steaming, which makes it difficult to manually detect the tank cleaning effect during the tank cleaning process. At present, commodity inspection agencies mainly rely on visual inspection of each tank and wiping the bulkhead with methanol to evaluate the tank cleaning effect. These methods are greatly affected by experience and randomness, and have large errors, making it difficult to quantify the tank cleaning effect. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a multi-sensor online detection system for tank washing wastewater of a chemical tanker, comprising:

[0005] Water supply tank washing pump, drainage tank washing pump, primary detection system, fine detection system and detection data processing and analysis system;

[0006] The water supply tank washing pump is connected to the cargo tank of the chemical ship and is used to clean the cargo tank of the chemical ship to generate tank washing wastewater;

[0007] The drainage tank washing pump is connected to the cargo tank of the chemical tanker and is used to collect the tank washing wastewater with a stable flow rate to enter the primary detection system;

[0008] The primary detection system is connected to the drainage tank washing pump and is used to detect the tank washing wastewater through multiple sensors to obtain basic physical parameters of the tank washing wastewater, judge the contamination degree of the tank washing wastewater based on the basic physical parameters, and obtain a judgment result. If the judgment result is qualified, the tank washing wastewater is transported to the fine detection system;

[0009] The fine detection system is connected to the primary detection system and is used to detect the tank washing wastewater, obtain a chromatogram of the tank washing wastewater, and calculate the content of chemical residues of different components based on the chromatogram;

[0010] The detection data processing and analysis system is connected to the primary detection system and the fine detection system respectively, and is used to process and analyze the judgment results and the contents of the chemical residues of different components, and display them in the form of a bar graph or a trend graph.

[0011] Preferably, the primary detection system comprises: a pH meter, a turbidity meter, a conductivity probe, a residual chlorine probe, a hypochlorous acid probe and a dissolved oxygen probe;

[0012] The pH meter is used to detect the pH value of the tank washing wastewater and determine the residual condition of acidic or alkaline chemicals based on the pH value;

[0013] The turbidity meter is used to detect the turbidity of the tank washing wastewater and determine the residual condition of the colored chemical substances based on the turbidity;

[0014] The conductivity probe is used to detect the conductivity of the tank washing wastewater and determine the ion concentration based on the conductivity;

[0015] The residual chlorine probe is used to detect the residual chlorine in the tank washing wastewater;

[0016] The hypochlorous acid probe is used to detect hypochlorous acid in the tank washing wastewater;

[0017] The dissolved oxygen probe is used to detect the dissolved oxygen content of the tank washing wastewater and to determine the content of oxygen molecules in the water based on the dissolved oxygen content.

[0018] Preferably, the primary detection system also includes: an industrial computer, which is used to construct a tank inspection index threshold, compare the pH value, the turbidity, the conductivity, the residual chlorine, the hypochlorous acid and the dissolved oxygen content with the tank inspection index threshold, if the characteristic value exceeds the tank inspection index threshold, the cargo hold of the chemical tanker is re-cleaned, if the characteristic value is lower than the tank inspection index threshold, the tank washing wastewater is transported to the fine detection system.

[0019] Preferably, the tank washing wastewater flowing out of the primary detection system is returned to the outlet pipe through a first one-way valve;

[0020] The outlet pipeline of the primary detection system is connected to the fine detection system through a one-way solenoid valve.

[0021] Preferably, tank washing wastewater with a steady flow rate is collected from the outlet pipe of the drainage tank washing pump through a throttle valve and enters the primary detection tank.

[0022] Preferably, the fine detection system comprises: a sampling subsystem, a detection subsystem and an analysis subsystem;

[0023] The sampling system is used to evenly mix the tank washing wastewater after the primary test until there are no bubbles and the pressure is stable, so as to obtain the liquid to be tested;

[0024] The detection subsystem is used to perform chromatographic detection on the liquid to be tested to obtain separated chemical components;

[0025] The analysis subsystem is used to convert the separated chemical components into corresponding electrical signals according to their concentrations. The electrical signals are output as a chromatogram of the sample to be tested after passing through an amplifier. The content of chemical residues of different components can be calculated based on the peak size and area in the chromatogram.

[0026] Preferably, the detection data processing and analysis system is also used to: issue an audible and visual alarm if the judgment result and the content of the chemical residues of different components exceed the threshold of the tank inspection index, are lower than the sensor resolution or exceed the sensor measurement range, and upload the judgment result and the chemical residues of different components to a mobile terminal through a wireless transmission module or export them via USB.

[0027] Compared with the prior art, the present invention has the following advantages and technical effects:

[0028] The present invention designs a multi-sensor online detection system for tank washing wastewater of chemical tankers, which consists of two parts: primary detection and fine detection, and the system has the functions of real-time data acquisition and processing, multi-parameter display\alarm\trend analysis, storage and wireless transmission.

[0029] The primary detection link of the developed online detection system uses multiple sensors such as pH meter, turbidity meter, conductivity probe, residual chlorine probe, hypochlorous acid probe and dissolved oxygen probe to detect basic physical parameters such as pH value, turbidity, conductivity, residual chlorine, hypochlorous acid, dissolved oxygen, etc. in the tank washing water, which can preliminarily determine the degree of pollution of the tank washing water. If the significant physical characteristic quantity in the tank washing water exceeds the threshold during the primary detection, it means that there are still many chemical residues in the tank washing water and it needs to be cleaned further; on the contrary, if the significant physical characteristic quantity detected does not exceed the threshold, further fine detection using gas chromatograph is required. The fine detection link can determine the composition and concentration of each chemical in the tank washing water, and determine whether the content of chemical residues in the tank washing water exceeds the standard. This can not only improve the overall detection accuracy of the system, but also avoid long-term online operation of fine detection equipment.

[0030] Multiple throttle valves and sampling pools are designed in the detection system to have a buffering effect, preventing the flow rate and pressure fluctuations of the liquid to be tested, so that the samples to be tested are evenly mixed, thereby improving the system stability and detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 This is a flow chart of online detection of tank washing wastewater from a chemical tanker according to an embodiment of the present invention;

[0033] Figure 2 is a structural diagram of a detection device according to an embodiment of the present invention;

[0034] Figure 3 This is a technical scheme diagram of a multi-sensor online detection system for tank washing wastewater of a chemical tanker according to an embodiment of the present invention;

[0035] Figure 4 4 is a system composition diagram of the fine detection link of an embodiment of the present invention. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Embodiment 1

[0039] This embodiment provides a multi-sensor online detection system for tank washing wastewater of a chemical tanker, comprising:

[0040] Water supply tank washing pump, drainage tank washing pump, primary detection system, fine detection system and detection data processing and analysis system;

[0041] The water supply tank washing pump is connected to the cargo tank of the chemical ship and is used to clean the cargo tank of the chemical ship to generate tank washing wastewater;

[0042] The drainage tank washing pump is connected to the cargo tank of the chemical tanker and is used to collect the tank washing wastewater with a stable flow rate to enter the primary detection system;

[0043] The primary detection system is connected to the drainage tank washing pump and is used to detect the tank washing wastewater through multiple sensors to obtain basic physical parameters of the tank washing wastewater, judge the contamination degree of the tank washing wastewater based on the basic physical parameters, and obtain a judgment result. If the judgment result is qualified, the tank washing wastewater is transported to the fine detection system;

[0044] The fine detection system is connected to the primary detection system and is used to detect the tank washing wastewater, obtain a chromatogram of the tank washing wastewater, and calculate the content of chemical residues of different components based on the chromatogram;

[0045] The detection data processing and analysis system is connected to the primary detection system and the fine detection system respectively, and is used to process and analyze the judgment results and the contents of the chemical residues of different components, and display them in the form of a bar graph or a trend graph.

[0046] In order to solve the problem of residual detection of tank washing wastewater from chemical ships, the online detection flow chart of tank washing wastewater designed in this embodiment is as follows: Figure 1As shown. The detection process consists of two parts, namely primary detection and fine detection. In the primary detection stage, pH meter, turbidity meter, conductivity probe, residual chlorine probe, hypochlorous acid probe, dissolved oxygen probe are used to detect the significant physical characteristics of tank washing water, and the cleanliness of tank washing water is preliminarily judged according to the test results. If the significant physical characteristic quantity detected exceeds the threshold, it means that the chemical residue is large and the cleaning system needs to be opened for further cleaning. If the significant physical characteristic quantity detected does not exceed the threshold, the fine detection stage is carried out. The fine detection stage uses liquid chromatography detection method to detect chemical residues. If there are chemical residues in the tank washing water, the spectrum of the corresponding chemical composition and concentration will be generated. By comparing the standard spectrum, the content of the tank washing water residue can be calculated to determine whether the cleaning requirements are met. The primary detection stage mainly uses multiple sensors such as pH meter, turbidity, conductivity, residual chlorine, hypochlorous acid, dissolved oxygen and other basic physical parameters in the tank washing water to preliminarily judge the degree of contamination of the tank washing water. The tank washing water introduced through the throttle valve flows smoothly, which helps to improve the detection accuracy. It also includes an industrial computer used to construct the tank inspection index threshold. The industrial computer summarizes the measurement results of the pH meter, turbidity meter, conductivity probe, dissolved oxygen and other probes. After comprehensive calculation and analysis, it preliminarily determines the physical and chemical properties of the tank washing water and decides whether the next step of fine detection is needed. Through the detection of pH value, the residual situation of acidic or alkaline chemicals can be preliminarily judged; through the detection of turbidity, the residual situation of colored chemicals can be preliminarily judged; through the detection of conductivity, the ion concentration in the tank washing water can be preliminarily judged; through the detection of dissolved oxygen, the content of oxygen molecules in the tank washing water can be judged. If the significant physical characteristic value of the primary detection exceeds the threshold of the tank inspection index, it means that there are more chemical residues in the liquid and it needs to be cleaned further. If the significant physical characteristic value of the detection is lower than the threshold of the tank inspection index, the fine detection link is carried out. The composition and concentration of each chemical in the tank washing water cannot be determined according to the primary detection results. Therefore, when the primary detection results are qualified, fine detection is required to determine whether the content of chemical residues in the tank washing water is qualified.

[0047] The structure of the integrated online detection device for tank washing wastewater of a chemical tanker designed in this embodiment is as follows: Figure 2 As shown in the figure, the device mainly includes display screen, wireless transmission, electronic control module, box, primary detection component, fine detection component and other parts. The device is connected to the external pipeline through the inlet and outlet liquid interface to realize the detection of liquid components. The primary detection results are displayed in real time on a smaller 7-inch screen, and the results of fine detection (color spectrum) are displayed on a 20-inch screen. The detection results can also be sent out through the wireless transmission module. The device is connected to the external pipeline through the inlet and outlet liquid. After the liquid to be detected enters the system, it is analyzed by the detection module. The detection data is output to the display or sent out through wireless transmission after conversion control by the electronic control module.

[0048] The technical solution of the multi-sensor online detection system for tank washing wastewater of a chemical tanker designed in this embodiment is as follows: Figure 3 As shown in the figure, the detection system is mainly composed of a tank washing water supply pump, a tank washing water discharge pump, a primary detection system, a fine detection system and a detection data processing and analysis system. The specific working process of the system is as follows: the detection system is connected to the tank washing wastewater outlet pipe, and the liquid to be tested with a stable flow is collected from the outlet pipe through the throttle valve and enters the primary detection tank. The detection tank is equipped with conventional physical characteristic detectors such as online detection pH probe, turbidity probe, conductivity probe, dissolved oxygen probe, etc. The tank washing water flowing out of the preliminary detection tank is returned to the outlet pipe through the first one-way valve; in addition, the outlet pipe of the primary detection tank is also connected to the fine detection system through a one-way solenoid valve. The start and stop of the one-way solenoid valve is controlled by the result of the primary detection. When the primary detection result is unqualified, the solenoid valve is not opened (normally closed), and when the primary detection is qualified, the solenoid valve is opened for fine detection. The fine detection stage uses the working principle of gas chromatograph to separate different chemical substances, and compares the resulting spectrum with the spectrum of reference substances. The material components can be preliminarily distinguished based on the matching degree of separation time. The content of the substance can be inferred based on the peak value and area of ​​the spectrum, and then it can be determined whether the residue content exceeds the standard and whether the cargo hold cleaning requirements are met.

[0049] The components of the fine detection system are as follows: Figure 4 As shown, the fine detection system includes: a sampling subsystem, a detection subsystem and an analysis subsystem; wherein the sampling subsystem includes a sampling pool, a high-precision plunger pump, a hydrogen carrier gas and other components. The fine detection link mainly uses the working principle of a gas chromatograph to detect the composition and content of various chemical residues in the tank washing water. The specific workflow is as follows: the tank washing water after the primary detection first enters the sampling pool. The sampling pool has a buffering effect, so that the liquid to be tested is evenly mixed, there are no bubbles, and the pressure is stable to ensure accurate sampling by the plunger pump. The excess liquid flows back to the main outlet pipe through a one-way valve. The liquid to be tested in the sampling pool is injected into the interface liner of the gas chromatograph through a high-precision plunger pump. The liquid to be tested is gasified at high temperature and connected to the carrier gas to form a mixed gas that enters the chromatographic column of the detection subsystem. The chromatographic column is the core component of the gas chromatograph. Its function is to separate the various components in the sample to be tested and transport the separated sample to the flame ionization monitor (FID) analysis subsystem. The FID analysis subsystem can convert the chemical components separated in the chromatographic column into corresponding electrical signals according to the concentration. The electrical signals are output as chromatograms of the samples to be tested after passing through the amplifier. The position of each peak in the chromatogram represents a component, and the peak height and peak area represent the content of the component. Therefore, the content of chemical residues of different components can be calculated based on the peak size and area in the chromatogram. Gas chromatography has high detection accuracy and can accurately determine whether the cargo hold of a chemical ship is clean and meet the requirements of the tank inspection standard.

[0050] The tank washing water detection data processing and analysis system mainly includes data acquisition and processing module, multi-parameter display, alarm, trend analysis module, storage module and wireless transmission module ( Figure 3 ). The system can centrally collect, process and analyze the data obtained from primary and fine inspections, and display them in the form of bar graphs or trend graphs. When the test results exceed the threshold of the inspection index, are lower than the sensor resolution, or exceed the sensor measurement range, the system will issue an audible and visual alarm. In addition, the test and analysis data can be exported via USB and uploaded to mobile terminals such as mobile phone APP through a wireless transmission module.

[0051] The beneficial effects of this embodiment are:

[0052] By developing a multi-sensor online detection system for tank washing wastewater from chemical tankers, it is possible to determine in real time whether the tank washing effect of the ship is qualified, solving the problem that traditional tank washing of chemical tankers relies entirely on the experience of the crew and there is excessive tank washing that consumes time, water and electricity.

[0053] By designing a two-level detection system of primary detection and fine detection, the fine detection system will automatically start operation after the primary detection is qualified, which not only improves the detection accuracy but also reduces the working time of the fine detection gas chromatograph, and prolongs the service life of the fine detection equipment gas chromatograph. Multiple throttle valves and sampling pools are designed in the system, which have a buffering effect to prevent the flow rate and pressure fluctuations of the liquid to be tested, and can also make the samples to be tested evenly mixed, improving the system stability and detection accuracy.

[0054] The primary detection stage mainly uses multiple sensors such as pH meter, turbidity meter, conductivity probe, residual chlorine probe, hypochlorous acid probe and dissolved oxygen probe to detect multiple physical parameters of tank washing water, solving the problem of different chemical cargoes' different sensitivity to sensors. For example, palm oil is more sensitive to turbidity meter, while acidic and alkaline chemicals are more sensitive to pH meter. Through the method of multi-sensor fusion analysis, the residual oil situation of chemicals can be detected more accurately, thereby improving the sensitivity and accuracy of detection.

[0055] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A multi-sensor online detection system for tank washing wastewater of a chemical tanker, characterized in that: include: Water supply tank washing pump, drainage tank washing pump, primary detection system, fine detection system and detection data processing and analysis system; The water supply tank washing pump is connected to the cargo tank of the chemical ship and is used to clean the cargo tank of the chemical ship to generate tank washing wastewater; The drainage tank washing pump is connected to the cargo tank of the chemical tanker and is used to collect the tank washing wastewater with a stable flow rate to enter the primary detection system; The primary detection system is connected to the drainage tank washing pump and is used to detect the tank washing wastewater through multiple sensors to obtain basic physical parameters of the tank washing wastewater, judge the contamination degree of the tank washing wastewater based on the basic physical parameters, and obtain a judgment result. If the judgment result is qualified, the tank washing wastewater is transported to the fine detection system; The fine detection system is connected to the primary detection system and is used to detect the tank washing wastewater, obtain a chromatogram of the tank washing wastewater, and calculate the content of chemical residues of different components based on the chromatogram; The detection data processing and analysis system is connected to the primary detection system and the fine detection system respectively, and is used to process and analyze the judgment results and the contents of the chemical residues of different components, and display them in the form of a bar graph or a trend graph.

2. The system according to claim 1, characterized in that The primary detection system includes: a pH meter, a turbidity meter, a conductivity probe, a residual chlorine probe, a hypochlorous acid probe and a dissolved oxygen probe; The pH meter is used to detect the pH value of the tank washing wastewater and determine the residual condition of acidic or alkaline chemicals based on the pH value; The turbidity meter is used to detect the turbidity of the tank washing wastewater and determine the residual condition of the colored chemical substances based on the turbidity; The conductivity probe is used to detect the conductivity of the tank washing wastewater and determine the ion concentration based on the conductivity; The residual chlorine probe is used to detect the residual chlorine in the tank washing wastewater; The hypochlorous acid probe is used to detect hypochlorous acid in the tank washing wastewater; The dissolved oxygen probe is used to detect the dissolved oxygen content of the tank washing wastewater and to determine the content of oxygen molecules in the water based on the dissolved oxygen content.

3. The system according to claim 2, characterized in that The primary detection system also includes: an industrial computer, which is used to construct a tank inspection index threshold, compare the pH value, the turbidity, the conductivity, the residual chlorine, the hypochlorous acid and the dissolved oxygen content with the tank inspection index threshold, if the characteristic value exceeds the tank inspection index threshold, the cargo hold of the chemical tanker is cleaned again, if the characteristic value is lower than the tank inspection index threshold, the tank washing wastewater is transported to the fine detection system.

4. The system according to claim 1, characterized in that The tank washing wastewater flowing out of the primary detection system returns to the outlet pipe through a first one-way valve; The outlet pipeline of the primary detection system is connected to the fine detection system through a one-way solenoid valve.

5. The system according to claim 1, characterized in that The tank washing wastewater with a steady flow rate is collected from the outlet pipe of the drainage tank washing pump through a throttle valve and enters the primary detection tank.

6. The system according to claim 1, characterized in that The fine detection system comprises: a sampling subsystem, a detection subsystem and an analysis subsystem; The sampling system is used to evenly mix the tank washing wastewater after the primary test until there are no bubbles and the pressure is stable, so as to obtain the liquid to be tested; The detection subsystem is used to perform chromatographic detection on the liquid to be tested to obtain separated chemical components; The analysis subsystem is used to convert the separated chemical components into corresponding electrical signals according to their concentrations. The electrical signals are output as a chromatogram of the sample to be tested after passing through an amplifier. The content of chemical residues of different components can be calculated based on the peak size and area in the chromatogram.

7. The system according to claim 1, characterized in that The detection data processing and analysis system is also used to: issue an audible and visual alarm if the judgment result and the content of the chemical residues of different components exceed the threshold of the tank inspection index, are lower than the sensor resolution or exceed the sensor measurement range, and upload the judgment result and the chemical residues of different components to a mobile terminal through a wireless transmission module or export them via USB.

Images