TWI423841B - Krauss Process Exhaust Gas Analyzer Exceptional Detection Method - Google Patents

Description

Method for detecting abnormality of exhaust gas analyzer in Claus process

The invention relates to a method for detecting an abnormality of an analysis device, in particular to a method for detecting an abnormality of an exhaust gas analyzer of a Claus process.

The Claus Process is a very important hydrogen sulfide gas desulfurization technology, which is widely used in industrial facilities such as petroleum refining, natural gas processing, tar sand treatment, coal gasification, smelting, coke ovens, etc. An acid gas containing hydrogen sulfide is then produced.

The Claus process is to oxidize 1/3 of the hydrogen sulfide in the acid gas with oxygen in the air to obtain sulfur dioxide, and then react with the remaining hydrogen sulfide to form sulfur. The air supply is important because of the oxidation reaction. Too much or too little air supply will reduce the conversion efficiency of sulfur.

Since the composition and concentration of sour gas cannot be completely analyzed on the line, and the optimal intake amount of air cannot be directly estimated by the composition of sour gas, the current practice is to use the tail gas generated by the Claus process to use the exhaust gas analyzer. The composition and concentration are analyzed, and a feedback value is obtained from the ratio of the concentration of hydrogen sulfide to sulfur dioxide in the exhaust gas, and the air intake amount is controlled by the feedback value to continue the Claus process.

It can be seen from the above description that the exhaust gas analyzer is an important key to maintain the conversion efficiency of sulfur in the Claus process, but when the exhaust gas analyzer fails or is not in time, the Claus process cannot be continuously and effectively performed. The abnormal means of the exhaust gas analyzer will cause the factory to have low production efficiency, the furnace temperature is out of control, and the abnormal increase of sulfur oxides in the coking wastewater leads to significant losses such as biochemical acidification. Therefore, the industry has been seeking an effective solution in the tail gas analysis. When the instrument is abnormal, it can quickly detect and strain, and can continue the Claus process stably and effectively.

Accordingly, it is an object of the present invention to provide a method of detecting an abnormality of an exhaust gas analyzer capable of detecting a Claus process.

Therefore, in the method for detecting an abnormality of the exhaust gas analyzer of the Claus process of the present invention, the Claus process produces sulfur by using acid gas and air, and analyzes the exhaust gas generated by the exhaust gas analyzer during the process of the Claus process. After the concentration of the component, a feedback value is obtained according to the concentration ratio of hydrogen sulfide to sulfur dioxide in the exhaust gas, and then the air intake amount is controlled by the feedback value to continue the Claus process, and the Claus process exhaust gas analyzer The abnormal detection method includes a water concentration obtaining step, a model establishing step, and a determining step.

The water concentration obtaining step takes most of the physical parameters of the acid gas to obtain the water concentration in the acid gas.

The model establishing step establishes an autoregressive moving average model by using a preset autoregressive order and a sliding average order, and extracts multiple feedback values from a feedback time value of a recent time point, together with the water concentration. Substituting the autoregressive moving average model yields a suggested value.

The determining step is to determine that the exhaust gas analyzer is abnormal when the difference between the recommended value and the feedback value of the latest time point exceeds a predetermined range.

The effect of the invention is: predicting the intake air amount by establishing the autoregressive moving average model, and using the water concentration as an error correction, so that the recommended value can more accurately determine whether the exhaust gas analyzer is abnormal, and repairing the exhaust gas During the period of the analyzer, the Klaus process is continued by controlling the amount of intake air of the air with the recommended value.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 1, a first preferred embodiment of the method for detecting abnormality of the exhaust gas analyzer of the Claus process of the present invention is shown in FIG. 1. The Claus process produces sulfur by acid gas and air, and In the process of the Claus process, the exhaust gas is analyzed by the exhaust gas analyzer, and then the feedback value is obtained according to the concentration ratio of hydrogen sulfide to sulfur dioxide in the exhaust gas, and then the air intake amount is controlled by the feedback value to continue. The Claus process is performed, and the method for detecting abnormality of the exhaust gas analyzer of the Claus process includes a moisture concentration obtaining step 11, a model establishing step 12, and a determining step 13.

The water concentration obtaining step 11 is to obtain the water concentration in the acid gas after extracting the temperature, pressure, and flow rate of the acid gas.

The model establishing step 12 establishes an autoregressive moving average model (ARMA) by using the autoregressive order and the sliding average order, and then extracting the feedback value from a recent time point within a predetermined period of time. A plurality of feedback values are obtained, and the recommended value is obtained by substituting the water concentration into the autoregressive moving average model, preferably, for example, Method of moments, Maximum likelihood estimates (MLE) The method is used to estimate the value of the parameters in the model, and the autoregressive moving average model is established.

The determining step 13 is to determine that the exhaust gas analyzer is abnormal when the difference between the recommended value and the feedback value of the latest time point exceeds a predetermined range.

The method for detecting abnormality of the tail gas analyzer of the Claus process of the present invention, by establishing the autoregressive moving average model to predict the intake air amount of the air, and using the feedback value of the latest time point to multi-feedback within a predetermined period of time The value is used as a basis for prediction, and since the concentration of water in the acid gas affects the amount of air that reacts with the acid gas, the amount of intake air must be adjusted accordingly, so the error is corrected by the concentration of the water so that the recommended value is obtained. More accurate to judge whether the exhaust gas analyzer is abnormal.

Referring to Fig. 2, the detection method of the abnormality of the exhaust gas analyzer of the Claus process of the present invention actually evaluates the test result, as shown in Fig. 2, the horizontal axis is the time point of the test, and the vertical axis is the air intake amount of the air. The average of the error between the feedback value and the corresponding recommended value during the evaluation test period is 2% and the standard deviation is 4%, which can achieve the expected efficacy. Before the evaluation, it is confirmed that the exhaust gas analyzer is working normally. And the feedback value is correct.

Referring to FIG. 3, a second preferred embodiment of the method for detecting abnormality of the exhaust gas analyzer of the Claus process of the present invention is similar to the first preferred embodiment, except that when the exhaust gas analyzer is abnormal The second preferred embodiment is strain treated in a temporary strain step 2.

The temporary strain step 2 controls the air intake amount of the air by the recommended value obtained in the model establishing step 12 to continue the Claus process. Preferably, the air intake amount of the air is first controlled by the recommended value. The process continues, and at the same time, the relevant instrument is inspected to confirm whether the exhaust gas analyzer is indeed abnormal, and the air intake amount is controlled by the recommended value during the confirmation or repair of the exhaust gas analyzer, so that the Claus process is in the exhaust gas. The analyzer can continue to operate during the repair process to reduce the incidence of Claus process anomalies and increase the stability of the Claus process.

In summary, the detection method of the exhaust gas analyzer abnormality of the Claus process of the present invention predicts the air intake amount by using the autoregressive moving average model, and further adjusts the error by using the water concentration in the acid gas, so that the recommended value is obtained. More accurate, and verified by the results of the actual evaluation test, the recommended value does achieve the expected efficacy, so it can indeed achieve the purpose of the present invention.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

11. . . Water concentration step

12. . . Model building step

13. . . Judgment step

2. . . Temporary contingency step

1 is a flow chart showing a first preferred embodiment of a method for detecting an abnormality of an exhaust gas analyzer of the Claus process of the present invention;

2 is a graph showing a time when the horizontal axis is the time point of the test and the vertical axis is the air intake amount of the air, illustrating the results of the actual evaluation test of the first preferred embodiment of FIG. 1;

Fig. 3 is a flow chart showing a second preferred embodiment of the method for detecting abnormality of the exhaust gas analyzer of the Claus process of the present invention.

11. . . Water concentration step

12. . . Model building step

13. . . Judgment step

Claims (4)

A method for detecting an abnormality of a tail gas analyzer of a Claus process, wherein the Claus process produces sulfur by acid gas and air, and analyzes the composition concentration of the exhaust gas generated by the tail gas analyzer during the process of the Claus process. Then, according to the concentration ratio of hydrogen sulfide to sulfur dioxide in the exhaust gas, a feedback value is obtained, and then the air intake amount is controlled by the feedback value to continue the Claus process, and the exhaust gas analyzer of the Claus process is abnormally detected. The measuring method comprises: a step of obtaining a water concentration, extracting a plurality of physical parameters of the acid gas to obtain a water concentration in the acid gas, wherein the temperature, the pressure, and the flow value of the acid gas are taken; a model establishing step is preset An autoregressive moving average model is used to establish an autoregressive moving average model, and multiple feedback values from a recent time point of the feedback value are extracted, and the autoregressive moving average model is substituted along with the water concentration. Then, a recommended value is obtained; and a determining step determines that the exhaust gas analyzer is abnormal when the difference between the recommended value and the feedback value of the latest time point exceeds a predetermined range. According to the detection method of the exhaust gas analyzer abnormality of the Claus process described in the first application of the patent scope, wherein the model establishing step is to establish the autoregressive moving average model with the autoregressive order and the sliding average order. According to the method for detecting an abnormality of the exhaust gas analyzer of the Claus process according to the second aspect of the patent application, wherein the model establishing step is to extract multiple feedbacks within a predetermined time period from the feedback value of the latest time point. value. According to the detection method of the tail gas analyzer abnormality of the Claus process described in the first application of the patent scope, the method further includes controlling the air into the air according to the recommended value. The amount of gas is used to continue the temporary strain step of the Claus process.