A self-checking method for detecting the sulfur content of marine fuel oil based on exhaust pollutants

Abstract

The present application relates to the technical field of fuel sulfur content detection, in particular to a self-checking marine fuel sulfur content detection method based on exhaust pollutants, comprising the following steps: step one: exhaust pollutant concentration measurement; step two: A / F value calculation; step three: A / F value checking; step four: fuel sulfur content inversion calculation. The present application can perform fuel sulfur content inversion calculation based on the exhaust pollutant measurement results under the engine running state, avoid the inconsistency between the sampled oil and the fuel used by the ship, expand the detection application range for special ships with difficult oil sampling, improve the law enforcement efficiency, obtain two independent data for calculating the key parameter A / F value by using different measurement principles, use the Hann window filtering method to preprocess the continuous measurement data, and introduce A / F value checking before fuel sulfur content inversion calculation, thereby reducing the influence of accidental errors on the calculation results, and improving the stability and reliability of the results.

Description

Technical Field

[0001] This invention relates to the field of fuel oil sulfur content detection technology, and in particular to a self-calibrating method for detecting the sulfur content of marine fuel oil based on exhaust pollutants. Background Technology

[0002] Currently, designating low-emission zones in port areas is the primary means of controlling air pollution in urban areas caused by ship emissions. Because low-sulfur fuel oil is significantly more expensive than high-sulfur fuel oil, illegal use of high-sulfur fuel oil frequently occurs within these zones, making them a key target for monitoring by transportation and environmental authorities. Current methods for monitoring the sulfur content of fuel oil mainly involve onboard sampling and remote sensing. However, onboard sampling is time-consuming, and given that ships typically have multiple fuel tanks, enforcement personnel struggle to verify the consistency between the sampled fuel and the fuel used during the ship's entry into port, potentially leading to regulatory loopholes. Remote sensing, when calculating SO2 concentration, suffers from low accuracy due to the uncertainty of CO2 concentration in exhaust gas, requiring the introduction of assumptions about engine operating conditions. Both methods have shortcomings and require further improvement. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a self-calibrated method for detecting the sulfur content of marine fuel oil based on exhaust pollutants.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a self-calibrating method for detecting the sulfur content of marine fuel oil based on exhaust pollutants, comprising the following steps:

[0005] Step 1: Measurement of exhaust pollutant concentration: Using an engine emission analyzer, continuously measure the concentrations (volume fractions) of CO, CO2, HC, NO, NO2 and SO2 in the exhaust gas of the ship engine at the exhaust pipe outlet. Simultaneously, use a wide-range oxygen sensor to continuously measure the A / F value of the fuel at the exhaust pipe outlet of the ship engine.

[0006] Step 2: Calculation of A / F value: Substitute the volume fraction of exhaust pollutants obtained in Step 1 into formulas (1) and (2), and calculate the A / F value based on the simplified oxygen balance equation for ship engine combustion.

[0007]

[0008]

[0009] In the above formula, [CO2], [CO], [NO], [NO2], [O2], [SO2] and [HC] are the molar concentrations of CO2, CO, NO, NO2, O2, SO2 and HC at the exhaust pipe outlet of the ship's engine, respectively.

[0010] Mair and Mfuel are the molar masses of air and fuel oil, respectively, where Mair = 28.96 g / mol and Mfuel = (12.01 + 1.008y) g / mol, and y is the H / C ratio of the fuel in the ship's engine.

[0011] Step 3: Verification of A / F value: After processing the A / F value calculated based on the exhaust pollutant concentration in Step 2 (referred to as the calculated A / F value) and the A / F value continuously measured by the wide-range oxygen sensor in Step 1 (referred to as the measured A / F value), the arithmetic mean of the calculated A / F value and the measured A / F value are obtained respectively, and then compared and verified.

[0012] Step 4: Inversion calculation of fuel sulfur content: For the continuous measurement data verified in Step 3, the A / F value is calculated second by second using the exhaust pollutant concentration in the original data. The second-by-second A / F value and SO2 volume fraction are substituted into formula (3) to calculate the fuel sulfur content second by second. After processing the fuel sulfur content second by second, the arithmetic mean of the fuel sulfur content in the measurement stage is calculated as the result output.

[0013]

[0014] In the above formula, m S,f The sulfur content of fuel oil (mass fraction, in mg / kg), v SO2,ex SO2 concentration in exhaust gas (volume fraction, unit: 10) -6 ).

[0015] To ensure the effectiveness of the engine emission analyzer and the wide-range oxygen sensor, the present invention is improved in that, in step one, both the engine emission analyzer and the wide-range oxygen sensor undergo zero-point calibration, range calibration, and linearization check before use.

[0016] To ensure the effectiveness of data acquisition, the present invention is improved in that, in step one, both the engine emission analyzer and the wide-range oxygen sensor are used under stable operating conditions and measured at a detection frequency of 1Hz.

[0017] To further improve the accuracy of the measurement data, the present invention is improved in that the continuous measurement time in step one is not less than 30 seconds.

[0018] In order to obtain different results for different fuels, the present invention is improved by setting the H / C ratio to 1.8 for diesel and 1.7 for fuel oil in step two.

[0019] To ensure the effectiveness of data processing, this invention includes an improvement whereby, in step three, the T4253 Hanning window filtering method is used to process the calculated and measured A / F values.

[0020] To accurately define the test results, the present invention improves upon this invention by stating that in step three, during the comparison and verification process, if the arithmetic mean of the calculated A / F value does not exceed 0.85-1.15 times the arithmetic mean of the measured A / F value, then the A / F value verification is considered successful; otherwise, the A / F value verification fails and the test is terminated.

[0021] To ensure the accuracy of the data, the present invention is improved by using the T4253 Hanning window filtering method to process the fuel sulfur content second by second in step four.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0023] 1. In this invention, the sulfur content of fuel can be calculated by measuring the exhaust pollutants under engine operating conditions, avoiding the situation where the oil sample taken by law enforcement officers may be inconsistent with the fuel used by the ship. At the same time, it expands the scope of application of the test for special ships where oil sampling is difficult and improves law enforcement efficiency.

[0024] 2. In this invention, two independent data streams are obtained using different measurement principles and the key parameter A / F value is calculated separately. The Hanning window filtering method is used to preprocess the continuous measurement data, and the A / F value verification is introduced before the fuel sulfur content inversion calculation. This reduces the impact of random errors in on-site measurement on the fuel sulfur content calculation results and improves the stability and reliability of the results. Attached Figure Description

[0025] Figure 1 This invention presents a schematic flowchart of a self-calibrated method for detecting the sulfur content of marine fuel oil based on exhaust pollutants. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] Example 1

[0029] Please see Figure 1 This invention provides a technical solution: a self-calibrated method for detecting the sulfur content of marine fuel oil based on exhaust pollutants, comprising the following steps:

[0030] Step 1: Measurement of exhaust pollutant concentration: Using an engine emission analyzer, continuously measure the concentrations (volume fractions) of CO, CO2, HC, NO, NO2 and SO2 in the exhaust gas of the ship engine at the exhaust pipe outlet. Simultaneously, use a wide-range oxygen sensor to continuously measure the A / F value of the fuel at the exhaust pipe outlet of the ship engine.

[0031] Step 2: Calculation of A / F value: Substitute the volume fraction of exhaust pollutants obtained in Step 1 into formulas (1) and (2), and calculate the A / F value based on the simplified oxygen balance equation for ship engine combustion.

[0032]

[0033]

[0034] In the above formula, [CO2], [CO], [NO], [NO2], [O2], [SO2] and [HC] are the molar concentrations of CO2, CO, NO, NO2, O2, SO2 and HC at the exhaust pipe outlet of the ship's engine, respectively.

[0035] Mair and Mfuel are the molar masses of air and fuel oil, respectively, where Mair = 28.96 g / mol and Mfuel = (12.01 + 1.008y) g / mol, and y is the H / C ratio of the fuel in the ship's engine.

[0036] Step 3: Verification of A / F value: After processing the A / F value calculated based on the exhaust pollutant concentration in Step 2 (referred to as the calculated A / F value) and the A / F value continuously measured by the wide-range oxygen sensor in Step 1 (referred to as the measured A / F value), the arithmetic mean of the calculated A / F value and the measured A / F value are obtained respectively, and then compared and verified.

[0037] Step 4: Inversion calculation of fuel sulfur content: For the continuous measurement data verified in Step 3, the A / F value is calculated second by second using the exhaust pollutant concentration in the original data. The second-by-second A / F value and SO2 volume fraction are substituted into formula (3) to calculate the fuel sulfur content second by second. After processing the fuel sulfur content second by second, the arithmetic mean of the fuel sulfur content in the measurement stage is calculated as the result output.

[0038]

[0039] In the above formula, m S,f The sulfur content of fuel oil (mass fraction, in mg / kg), v SO2,ex SO2 concentration in exhaust gas (volume fraction, unit: 10) -6 ).

[0040] In this invention, the sulfur content of fuel can be calculated by measuring exhaust pollutants while the engine is running. This avoids the possibility that the fuel sampled by law enforcement officers may be inconsistent with the fuel used by the ship. At the same time, it expands the scope of application for special ships where fuel sampling is difficult, improves law enforcement efficiency, and uses different measurement principles to obtain two independent data streams and calculate the key parameter A / F value separately. The Hanning window filtering method is used to preprocess the continuous measurement data, and the A / F value is introduced for verification before the fuel sulfur content inversion calculation. This reduces the impact of random errors in on-site measurement on the fuel sulfur content calculation results and improves the stability and reliability of the results.

[0041] In step one, both the engine emission analyzer and the wide-range oxygen sensor undergo zero-point calibration, range calibration, and linearization checks before use. This calibration improves the accuracy of subsequent data measurements. During use, both the engine emission analyzer and the wide-range oxygen sensor are measured under stable operating conditions at a detection frequency of 1Hz for at least 30 seconds to ensure the continuity and validity of the measurement data, thereby ensuring the accuracy of subsequent calculations.

[0042] In step two, the H / C ratios for diesel and fuel oil are set to 1.8 and 1.7 respectively. This allows for further definition of the H / C ratio for different fuels (diesel and fuel oil), ensuring the accuracy of subsequent calculation results.

[0043] In step three, the T4253 Hanning window filtering method is used to process the calculated and measured A / F values. This ensures the effectiveness of the processing. During the comparison and verification process, if the arithmetic mean of the calculated A / F values ​​does not exceed 0.85-1.15 times the arithmetic mean of the measured A / F values, the A / F value verification is considered successful. Otherwise, the A / F value verification fails, the test is stopped, and the verification result is defined to facilitate the staff to quickly obtain the verification result.

[0044] In step four, the T4253 Hanning window filtering method is used to process the fuel sulfur content second by second, which can fully ensure the accuracy of subsequent data processing and improve the stability and reliability of the results.

[0045] Working principle: First, using an engine emission analyzer that has undergone zero-point calibration, range calibration, and linearization checks, the concentrations (volume fractions) of CO, CO2, HC, NO, NO2, and SO2 in the exhaust gas of a ship engine operating under stable conditions are continuously measured at a detection frequency of 1Hz for no less than 30s at the exhaust pipe outlet. Simultaneously, using a calibrated wide-range oxygen sensor, the A / F value of the fuel is continuously measured at a detection frequency of 1Hz for no less than 30s at the exhaust pipe outlet of the ship engine. Then, the measured exhaust pollutant volume fractions are substituted into formulas (1) and (2), and the A / F value is calculated based on the simplified ship engine combustion oxygen balance equation. The T4253 Hanning window filtering method is used to filter the calculated A / F value. After processing the A / F value and the measured A / F value, the arithmetic mean of the calculated A / F value and the measured A / F value are output respectively. When the result of the arithmetic mean of the calculated A / F value does not exceed 0.85-1.15 times the result of the arithmetic mean of the measured A / F value, the A / F value verification is passed. Otherwise, the A / F value verification fails and the detection is terminated. For the continuous measurement data that has passed the verification, the A / F value is calculated second by second using the exhaust pollutant concentration in the original data. The second-by-second A / F value and SO2 volume fraction are substituted into formula (3) to calculate the fuel sulfur content second by second. After processing the fuel sulfur content second by second using the T4253 Hanning window filtering method, the arithmetic mean of the fuel sulfur content in the measurement stage is calculated as the result output, and the detection of fuel sulfur content can be completed.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A self-calibrated method for detecting sulfur content in marine fuel oil based on exhaust pollutants, characterized in that, Includes the following steps: Step 1: Measurement of exhaust pollutant concentration: Using an engine emission analyzer, continuously measure the concentration and volume fraction of CO, CO2, HC, NO, NO2 and SO2 in the exhaust gas of the ship engine at the exhaust pipe outlet. Simultaneously, use a wide-range oxygen sensor to continuously measure the A / F value of the fuel at the exhaust pipe outlet of the ship engine. Step 2: Calculation of A / F value: Substitute the volume fraction of exhaust pollutants obtained in Step 1 into formulas (1) and (2), and calculate the A / F value based on the simplified oxygen balance equation for ship engine combustion. （1） (2) In the above formula, [CO2], [CO], [NO], [NO2], [O2], [SO2] and [HC] are the molar concentrations of CO2, CO, NO, NO2, O2, SO2 and HC at the exhaust pipe outlet of the ship's engine, respectively. Mair and Mfuel are the molar masses of air and fuel oil, respectively, where Mair = 28.96 g / mol and Mfuel = (12.01 + 1.008y) g / mol, and y is the H / C ratio of the fuel in the ship's engine. Step 3: Verification of A / F values: The A / F values ​​calculated based on exhaust pollutant concentrations in Step 2 (hereinafter referred to as calculated A / F values) and the A / F values ​​continuously measured using a wide-range oxygen sensor in Step 1 (hereinafter referred to as measured A / F values) are processed to obtain the arithmetic mean of the calculated A / F values ​​and the measured A / F values, and then compared and verified. Step 4: Inversion calculation of fuel sulfur content: For the continuous measurement data verified in Step 3, the A / F value is calculated second by second using the exhaust pollutant concentration in the original data. The second-by-second A / F value and SO2 volume fraction are substituted into formula (3) to calculate the fuel sulfur content second by second. After processing the fuel sulfur content second by second, the arithmetic mean of the fuel sulfur content in the measurement stage is calculated as the result output. (3) In the above formula, m S,f This refers to the sulfur content of fuel oil, expressed as a mass fraction, in mg / kg. SO2,ex SO2 concentration in exhaust gas, volume fraction, unit:

10. -6 .

2. The self-calibrated marine fuel oil sulfur content detection method based on exhaust pollutants according to claim 1, characterized in that: In step one, both the engine emission analyzer and the wide-range oxygen sensor undergo zero-point calibration, range calibration, and linearization checks before use.

3. The self-calibrated method for detecting sulfur content in marine fuel oil based on exhaust pollutants according to claim 1, characterized in that: In step one, both the engine emission analyzer and the wide-range oxygen sensor are used under stable operating conditions and are measured at a detection frequency of 1Hz.

4. The self-calibrated marine fuel oil sulfur content detection method based on exhaust pollutants according to claim 1, characterized in that: In step one, the continuous measurement time shall not be less than 30 seconds.

5. The self-calibrated method for detecting sulfur content in marine fuel oil based on exhaust pollutants according to claim 1, characterized in that: In step two, the H / C ratios for diesel and fuel oil are 1.8 and 1.7, respectively.

6. The self-calibrated method for detecting sulfur content in marine fuel oil based on exhaust pollutants according to claim 1, characterized in that: In step three, the T4253 Hanning window filtering method is used to process the calculated A / F value and the measured A / F value.

7. The self-calibrated marine fuel oil sulfur content detection method based on exhaust pollutants according to claim 1, characterized in that: In step three, during the comparison and verification process, if the arithmetic mean of the calculated A / F value does not exceed 0.85-1.15 times the arithmetic mean of the measured A / F value, it indicates that the A / F value verification has passed; otherwise, the A / F value verification has failed, and the test is terminated.

8. The self-calibrated method for detecting sulfur content in marine fuel oil based on exhaust pollutants according to claim 1, characterized in that: In step four, the T4253 Hanning window filtering method is used to process the fuel sulfur content second by second.

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