Method for measuring impurity ion carrying coefficient in urea hydrolysis ammonia production product gas

Abstract

The embodiment of the invention provides a method for measuring the impurity ion carrying coefficient in urea hydrolysis ammonia production product gas. The method comprises the following steps: collecting an absorption liquid sample; the absorption liquid sample comprises an acid solution absorbing ammonia gas; measuring the content of ammonia gas and impurity ions in the absorption liquid; calculating the total amount of the product gas according to the content of the ammonia gas and the concentration of the urea solution in the hydrolyzer; the impurity ion carrying coefficient in the product gas is calculated according to the content proportional relation of the ammonia gas and the impurity ions. According to the method, the ammonia gas in the product gas is completely absorbed by adopting an acidic solution to absorb the product gas, and then the content of the ammonia and the content of impurity ions in the absorption solution are measured to quantitatively calculate the content of impurities carried by the product gas.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of corrosion and corrosion prevention of urea-ammonia production systems in thermal power plants, and specifically relate to a method for determining the impurity ion carrying coefficient in a product gas produced by hydrolyzing urea to produce ammonia. Background Art

[0002] The flue gas denitrification device of thermal power plants is used to remove NO in flue gas. x The SCR (selective catalytic reduction) flue gas denitrification devices put into operation early generally use liquid ammonia as a reducing agent, but liquid ammonia is a major hazardous substance and there are major safety hazards during transportation, storage and use. Once a leakage accident occurs, it will have serious consequences for the environment and public health.

[0003] According to different decomposition principles, urea ammonia production technology can be divided into two categories: hydrolysis ammonia production and thermal decomposition ammonia production. Compared with the two, the urea hydrolysis ammonia production method has a higher efficiency in converting urea into ammonia, low system energy consumption, and relatively less subsequent maintenance investment. Currently, most power plants choose to adopt the urea hydrolysis ammonia production process.

[0004] With the commissioning of the urea hydrolysis ammonia production unit, new problems have gradually emerged, such as stress corrosion cracking and damage to the hydrolyzer heat exchange tube, resulting in the shutdown of the denitrification system. Sodium chloride crystals appear on the hydrolyzer heat exchange tube, affecting the heat exchange efficiency of the hydrolyzer and the normal operation of the denitrification system. More seriously, a large amount of chloride ions will cause intergranular corrosion, stress corrosion cracking and uniform corrosion of the 316L stainless steel hydrolyzer and corrosion cracking of the product gas pipeline. According to the investigation and analysis, the corrosion and surface crystallization of the heat exchange tube of the urea hydrolysis ammonia production unit are mainly related to the excessive chloride in the incoming urea and the sewage control method of the urea hydrolyzer. The corrosion of the product gas pipeline is related to the control of operating parameters, and the influence of impurities carried in the product gas cannot be ruled out. At present, there is no method for quantitatively measuring the content of impurity ions such as chloride ions and sodium ions in the product gas.

[0005] Therefore, how to solve the above problems has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a method for determining the impurity ion carrying coefficient in ammonia product gas produced by urea hydrolysis.

[0007] One aspect of an embodiment of the present disclosure provides a method for determining the impurity ion carrying coefficient in a product gas for producing ammonia by hydrolysis of urea, comprising:

[0008] collecting an absorption liquid sample; the absorption liquid sample comprises an acid solution absorbed with ammonia;

[0009] Measure the ammonia and impurity ion content in the absorption liquid;

[0010] Calculate the total amount of product gas based on the ammonia content and the concentration of urea solution in the hydrolyzer;

[0011] The impurity ion carrying coefficient in the product gas is calculated based on the content ratio of ammonia and impurity ions.

[0012] Optionally, the impurity ions include chloride ions and sodium ions;

[0013] Among them, the sodium ion content is measured by graphite furnace atomic absorption method; the chloride ion content is measured by silver nitrate spectrophotometry or ion chromatography; and the ammonia content in the absorption liquid is measured by Nessler's reagent spectrophotometry or ion chromatography.

[0014] Optionally, the total amount of product gas is calculated according to the content of ammonia and the concentration of urea solution in the hydrolyzer, including:

[0015] The concentration of ammonia in the absorption liquid is determined by measuring the ammonia content in the absorption liquid and using the calculation formula: Calculate the total amount of product gas, where: is the concentration of ammonia in the absorption liquid; C 产品气 is the concentration of product gas in the absorption liquid, is the mass fraction of ammonia in the product gas at different urea concentrations.

[0016] Optionally, the mass fraction of ammonia in the product gas at different urea concentrations is given by the conditional formula: Calculated, where is the urea concentration, and They are respectively the corresponding masses of ammonia and urea in the product gas when the chemical reaction of urea hydrolysis to produce ammonia reaches dynamic equilibrium.

[0017] Optionally, the product gas includes ammonia, carbon dioxide and water vapor. After the urea hydrolysis reaction to produce ammonia reaches dynamic equilibrium, the mass percentage of each component of urea and product gas satisfies the conditional formula: In the formula, are the mass percentages of ammonia, carbon dioxide and water vapor in the product gas respectively;

[0018] The mass relationship between urea and each component of product gas satisfies the conditional formula: In the formula, is the mass of carbon dioxide in the product gas, is the mass of water vapor in the product gas.

[0019] Optionally, the calculation of the impurity ion carrying coefficient in the product gas includes: determining the concentration of the impurity ions in the absorption liquid by measuring the content of the impurity ions in the absorption liquid; the impurity ion carrying coefficient in the product gas is determined by the conditional formula: Calculated, where δ 杂质离子 is the impurity ion carrying coefficient, C d1 is the concentration of impurity ions in the absorption liquid, V 吸收液 is the volume of the absorption liquid, C d2 is the concentration of impurity ions in urea.

[0020] Optionally, the method further includes: calculating the amount of acid solution required for the urea hydrolysis reaction to produce ammonia according to the ammonia percentage in the product gas produced by urea solutions of different concentrations and the quality of the product gas, as well as the acid solution parameters.

[0021] Optionally, the ammonia content in the product gas is determined by the conditional formula: Calculate, where m is the product gas quality;

[0022] The acid solution parameters include acid solution concentration and acid solution density, wherein based on the calculated ammonia mass, acid solution concentration and acid solution density, the conditional formula is: Calculate the amount of acid solution required; where V 酸溶液 is the amount of acid solution required, M 酸溶液 is the molar mass of the acid solution, ρ1 is the concentration of the acid solution, ρ2 is the density of the acid solution, is the molar mass of ammonia.

[0023] Optionally, the acid solution includes a nitric acid solution.

[0024] The beneficial effects of the embodiments of the present disclosure include:

[0025] The present invention adopts the method of absorbing the product gas with an acidic solution to achieve the purpose of completely absorbing ammonia in the product gas, and then determines the ammonia content and the impurity ion content in the absorption liquid to quantitatively calculate the content of impurities carried by the product gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a method for determining the impurity ion carrying coefficient in a product gas for producing ammonia by hydrolysis of urea according to another embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] The following is a further detailed description of the implementation methods of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the error tolerance range. "Parallel" is not parallel in the strict sense, but within the error tolerance range.

[0029] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0030] like Figure 1 As shown, a method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia comprises:

[0031] S101, collecting an absorption liquid sample; the absorption liquid sample comprises an acid solution that absorbs ammonia.

[0032] S102. Measure the ammonia and impurity ion contents in the absorption liquid.

[0033] S103. Calculate the total amount of product gas according to the content of ammonia and the concentration of urea solution in the hydrolyzer.

[0034] S104. Calculate the impurity ion carrying coefficient in the product gas based on the content ratio of ammonia and impurity ions.

[0035] The present invention adopts the method of absorbing the product gas with an acidic solution to achieve the purpose of completely absorbing ammonia in the product gas, and then determines the ammonia content and the impurity ion content in the absorption liquid to quantitatively calculate the content of impurities carried by the product gas.

[0036] In some embodiments, the impurity ions include chloride ions and sodium ions. The sodium ion content is measured by graphite furnace atomic absorption spectrometry, the chloride ion content is measured by silver nitrate spectrophotometry or ion chromatography, and the ammonia content in the absorption liquid is measured by Nessler's reagent spectrophotometry or ion chromatography.

[0037] In some embodiments, the total amount of product gas is calculated based on the ammonia content and the concentration of the urea solution in the hydrolyzer, including:

[0038] The concentration of ammonia in the absorption liquid is determined by measuring the ammonia content in the absorption liquid and using the calculation formula: Calculate the total amount of product gas, where: is the concentration of ammonia in the absorption liquid, C 产品气 is the concentration of product gas in the absorption liquid, is the mass fraction of ammonia in the product gas at different urea concentrations.

[0039] In some embodiments, the mass fraction of ammonia in the product gas at different urea concentrations is expressed by the conditional formula: Calculated, where is the urea concentration, and They are respectively the corresponding masses of ammonia and urea in the product gas when the chemical reaction of urea hydrolysis to produce ammonia reaches dynamic equilibrium.

[0040] In some embodiments, the product gas includes ammonia, carbon dioxide and water vapor. After the urea hydrolysis reaction to produce ammonia reaches dynamic equilibrium, the mass percentage of each component of urea and product gas satisfies the conditional formula: In the formula, are the mass percentages of ammonia, carbon dioxide and water vapor in the product gas respectively.

[0041] The mass relationship between urea and each component of product gas satisfies the conditional formula: In the formula, is the mass of carbon dioxide in the product gas, is the mass of water vapor in the product gas.

[0042] In some embodiments, the calculation of the impurity ion carrying coefficient in the product gas includes: determining the concentration of the impurity ions in the absorption liquid by measuring the content of the impurity ions in the absorption liquid, and the impurity ion carrying coefficient in the product gas is calculated by the conditional formula: Calculated, where δ 杂质离子 is the impurity ion carrying coefficient, C d1 is the concentration of impurity ions in the absorption liquid, V 吸收液 is the volume of the absorption liquid, C d2 is the concentration of impurity ions in urea.

[0043] In some embodiments, the method further includes calculating the amount of acid solution required for the urea hydrolysis reaction to produce ammonia based on the ammonia percentage in the product gas and the quality of the product gas produced by urea solutions of different concentrations, as well as the acid solution parameters.

[0044] In some embodiments, the ammonia content in the product gas is determined by the conditional formula: Calculate, where m is the product gas quality.

[0045] The acid solution parameters include acid solution concentration and acid solution density, wherein based on the calculated ammonia mass, acid solution concentration and acid solution density, the conditional formula is: Calculate the amount of acid solution required, where V 酸溶液 is the amount of acid solution required, M 酸溶液 is the molar mass of the acid solution, ρ1 is the concentration of the acid solution, ρ2 is the density of the acid solution, is the molar mass of ammonia.

[0046] In some embodiments, the acid solution includes a nitric acid solution.

[0047] In some embodiments, the acid solution is a 65% nitric acid solution with a density of 1.4 g / cm 3 .

[0048] A specific example provided by the present disclosure includes:

[0049] The chemical reaction equation for the hydrolysis of urea to produce ammonia is as follows:

[0050]

[0051] In an example provided by the present disclosure, the specific process of urea hydrolysis to produce ammonia is as follows: urea solution is decomposed to produce ammonia and carbon dioxide gas under the conditions of pressure of 0.6-0.7MPa and temperature of 150-160°C, and is transported to the denitration ammonia injection system through the product gas pipeline. The liquid level of the hydrolyzer is controlled to remain unchanged during operation. The product gas is mainly composed of ammonia, carbon dioxide and water vapor, and its composition ratio is related to the concentration of urea in the urea hydrolyzer. In the chemical reaction equation for urea hydrolysis to produce ammonia, the molar ratio of urea: water: ammonia: carbon dioxide is 1:1:2:1, and the specific analysis is shown in the following table:

[0052]

[0053] Based on the above table, we can know that the product gas consists of ammonia, carbon dioxide and water vapor. The urea solution is regarded as 1 part. During the operation of the urea hydrolyzer, the liquid level is always kept unchanged. When the urea hydrolysis reaction of the hydrolyzer to produce ammonia reaches dynamic equilibrium, the urea concentration and the proportion of each component of the product gas are also relatively stable. Specifically, the following formula can be obtained:

[0054]

[0055] in, are the mass percentages of ammonia, carbon dioxide and water vapor in the product gas respectively.

[0056]

[0057] in, is the concentration of urea in the urea hydrolyzer, 34 is the mass of ammonia in one part of the product gas at the corresponding urea concentration, 44 is the mass of carbon dioxide in one part of the product gas at the corresponding urea concentration, It is the mass of water vapor in one portion of product gas at the corresponding urea concentration (unit: g).

[0058] From this, the mass fraction of ammonia in the product gas at different urea concentrations can be calculated as:

[0059]

[0060] Similarly, according to the above formula, we can also get (carbon dioxide) and Water vapor mass fraction. Specifically, ωH2O=1-ωNH3-ωCO2,

[0061] Among them, by quantitatively measuring the amount of ammonia in the product gas, the amount of total product gas can be indirectly obtained. The specific calculation formula is as follows:

[0062]

[0063] in is the concentration of ammonia in the absorption liquid (in mg / L), C 产品气 It is the concentration of product gas in the absorption liquid (unit: mg / L).

[0064] The present invention adopts the method of absorbing the product gas with an acidic solution to achieve the purpose of completely absorbing ammonia in the product gas. In order to ensure the accuracy of the subsequent measurement of the impurity chloride ion result, a nitric acid solution is selected as the absorption liquid. The amount of nitric acid required is calculated according to the content of ammonia in the product gas produced by the urea solution of different concentrations in the hydrolyzer and the planned amount of gas sample.

[0065] The calculation steps disclosed in the present invention include: taking the product gas weight as mg, then the amount of ammonia in the product gas is (unit: g) is:

[0066]

[0067] Among them, 1 mol of NH3 needs 1 mol of HNO3 to neutralize and absorb to form ammonium nitrate solution. Then, 65% nitric acid solution is needed to absorb mg of ammonia in the product gas:

[0068]

[0069] 65% is the mass fraction of concentrated nitric acid, and 1.4 is the density of 65% nitric acid solution (unit: g / cm 3 ); The volume of 65% nitric acid solution.

[0070] According to the calculated required amount of nitric acid solution, the ammonia in the product gas can be completely absorbed by adding excess nitric acid solution to the sampling device. By measuring the ammonia content in the sample taken, the amount of ammonia absorbed by the sampling device can be accurately determined. (Unit is mg / L).

[0071] The specific steps include:

[0072] Step 1: Obtain an absorption liquid sample, wherein the absorption liquid sample comprises an acid solution that absorbs ammonia.

[0073] Step 2, determining the contents of ammonia, chloride ions and sodium ions in the absorption liquid sample, wherein the sodium ion content is measured by graphite furnace atomic absorption spectrophotometry, the chloride ion content is measured by silver nitrate spectrophotometry or ion chromatography, and the ammonia content in the absorption liquid is measured by Nessler's reagent spectrophotometry or ion chromatography.

[0074] Step 3: The total amount of product gas can be calculated based on the ammonia content and the concentration of the urea solution in the hydrolyzer. The carrying coefficient of the chloride ion content in the product gas is calculated by the ratio of ammonia to chloride ions, and the carrying coefficient of the sodium ion content in the product gas is calculated by the ratio of ammonia to sodium ions, wherein the product gas includes ammonia, carbon dioxide and water vapor.

[0075] Step 3.1, the carrying coefficient of the chloride ion content carried by the product gas is calculated by the ratio of ammonia to chloride ions, and the conditional formula is satisfied:

[0076]

[0077] is the chloride ion concentration in the absorption liquid, mg / L; is the concentration of ammonia in the absorption liquid, mg / L; V 吸收液 is the volume of absorption liquid + product gas; 60 is the molar mass of urea; It is the chloride ion concentration in the wastewater from the urea hydrolyzer (mg / L).

[0078] If the measured ammonia content in the sampling device is 80g / L, the chloride ion is 35μg / L, the sodium ion is 23μg / L, the urea solution concentration is 50%, and the chloride ion content in the urea hydrolyzer wastewater is 1000mg / L (25℃), then the carrying coefficient of the product gas for chloride ions is [35÷(80×120÷34)] / 1000=0.0124%. Similarly, if the sodium ion content in the urea hydrolyzer wastewater is 1000mg / L, it can be calculated that the carrying coefficient of the product gas for sodium ions is 23÷(80×120÷34)] / 1000=0.0082%.

[0079] Furthermore, the amount of nitric acid solution required is calculated according to the ammonia content in the product gas produced by urea solutions of different concentrations and the quality of the product gas.

[0080] Specifically, the ammonia mass fraction is calculated according to the ammonia content in the product gas produced by the urea solution of different concentrations and the mass of the product gas, wherein the ammonia content in the product gas produced by the urea solution of different concentrations satisfies the conditional formula:

[0081]

[0082] In the formula, is the percentage of ammonia in the product gas, is the concentration of urea solution, 34 is the chemical formula weight of ammonia, and 60 is the chemical formula weight of urea;

[0083] The mass calculation of ammonia in the product gas satisfies the conditional formula:

[0084]

[0085] If the equilibrium urea solution concentration in the urea hydrolyzer is 50%, and 1000g of product gas is collected, the mass of ammonia in the product gas is:

[0086]

[0087] Wherein, 1000 is the product gas mass (g), 50% is the concentration of urea solution, 34 is the chemical formula weight of ammonia, and 60 is the chemical formula weight of urea.

[0088] Step 1.1.2, according to the mass of ammonia in the product gas, the concentration of nitric acid solution and the density of nitric acid solution, calculate the amount of nitric acid solution required; wherein the amount of nitric acid solution required satisfies the conditional formula:

[0089]

[0090] Where 63 is the chemical amount of nitric acid, is the mass of ammonia in the ammonia product gas, 65% is the mass fraction (concentration) of concentrated nitric acid, and 1.4 is the density of 65% nitric acid solution (in g / cm 3 ).

[0091] In one example: it is planned to take 1000g of product gas, and the content of urea solution in the urea hydrolyzer is 50%, so the amount of ammonia is about 1000×{34÷[60×(1÷50%)]}=283.3g, wherein 1mol of NH3 requires 1mol of HNO3 to neutralize and absorb to form ammonium nitrate solution, and the amount of 65% nitric acid solution required to absorb the ammonia in 1000g of product gas is: 63×(283.3÷17) / (65%×1.4)=1156mL (where 65% is the mass fraction of concentrated nitric acid, and 1.4 is the density of 65% nitric acid solution). According to the calculated required amount of nitric acid solution, the ammonia in the product gas can be completely absorbed by adding an excess of nitric acid solution to the sampling device, and the amount of ammonia absorbed by the sampling device can be accurately determined by measuring the content of ammonia in the sample taken (in mg / L). Then measure the chloride ion and sodium ion content in the sample, the concentration of urea solution, chloride ion and sodium ion content in the urea hydrolyzer, and the chloride ion or sodium ion content carried by the product gas through the proportional relationship. For example, if the ammonia content in the sampling device is measured to be 80g / L, the chloride ion is 35μg / L, the sodium ion is 23μg / L, the urea solution concentration is 50%, and the chloride ion content in urea is 1000mg / L (25℃), then the chloride ion carrying coefficient of the product gas is [35÷(80×120÷34)] / 1000=0.0124%. Similarly, if the sodium ion content is 1000mg / L, it can be calculated that the sodium ion carrying coefficient of the product gas is 23÷(80×120÷34)] / 1000=0.0082%.

[0092] Because the ammonia in the product gas is absorbed by the nitric acid solution, the sample cation ammonium ion and anion nitrate ion in the sampling device are very high, belonging to the g / L level, while the chloride ion and sodium ion are at the μg / L level, with a difference of 10 6 If ion chromatography is used, it is often necessary to dilute many times in order not to contaminate the chromatographic column. At this time, the errors of the measured chloride ion and sodium ion contents are too large and difficult to measure accurately. Therefore, the present invention provides a detection method for sodium ion, chloride ion and ammonia content, respectively, wherein the sodium ion is measured by graphite furnace atomic absorption method, the chloride ion is measured by silver nitrate spectrophotometry (the cuvette is selected to be 100 mm), and the ammonia content is measured by Nessler's reagent spectrophotometry.

[0093] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia, characterized in that: include: collecting an absorption liquid sample; the absorption liquid sample comprises an acid solution absorbed with ammonia; Measure the ammonia and impurity ion content in the absorption liquid; Calculate the total amount of product gas based on the ammonia content and the concentration of urea solution in the hydrolyzer; The impurity ion carrying coefficient in the product gas is calculated based on the content ratio of ammonia and impurity ions.

2. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 1, characterized in that: The impurity ions include chloride ions and sodium ions; Among them, the sodium ion content is measured by graphite furnace atomic absorption method; the chloride ion content is measured by silver nitrate spectrophotometry or ion chromatography; and the ammonia content in the absorption liquid is measured by Nessler's reagent spectrophotometry or ion chromatography.

3. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 1, characterized in that: The total amount of product gas is calculated based on the ammonia content and the concentration of the urea solution in the hydrolyzer, including: The concentration of ammonia in the absorption liquid is determined by measuring the ammonia content in the absorption liquid and using the calculation formula: Calculate the total amount of product gas, where: is the concentration of ammonia in the absorption liquid; C 产品气 is the concentration of product gas in the absorption liquid, is the mass fraction of ammonia in the product gas at different urea concentrations.

4. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 3, characterized in that: The mass fraction of ammonia in the product gas at different urea concentrations is given by the conditional formula: Calculated, where is the urea concentration, and They are respectively the corresponding masses of ammonia and urea in the product gas when the chemical reaction of urea hydrolysis to produce ammonia reaches dynamic equilibrium.

5. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 4, characterized in that: The product gas includes ammonia, carbon dioxide and water vapor. After the urea hydrolysis reaction to produce ammonia reaches dynamic equilibrium, the mass percentage of each component of urea and product gas meets the conditional formula: In the formula, are the mass percentages of ammonia, carbon dioxide and water vapor in the product gas respectively; The mass relationship between urea and each component of product gas satisfies the conditional formula: In the formula, is the mass of carbon dioxide in the product gas, is the mass of water vapor in the product gas.

6. A method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 3 or 4, characterized in that: The calculation of the impurity ion carrying coefficient in the product gas includes: determining the concentration of the impurity ions in the absorption liquid by measuring the content of the impurity ions in the absorption liquid; the impurity ion carrying coefficient in the product gas is determined by the conditional formula: Calculated, where δ 杂质离子 is the impurity ion carrying coefficient, C d1 is the concentration of impurity ions in the absorption liquid, V 吸收液 is the volume of the absorption liquid, C d2 is the concentration of impurity ions in urea.

7. A method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to any one of claims 3 to 5, characterized in that: Also includes: The amount of acid solution required for the urea hydrolysis reaction to produce ammonia is calculated based on the ammonia percentage and quality of the product gas produced by urea solutions of different concentrations, as well as the acid solution parameters.

8. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 7, characterized in that: The ammonia content in the product gas is determined by the conditional formula: Calculate, where m is the product gas quality; The acid solution parameters include acid solution concentration and acid solution density, wherein based on the calculated ammonia mass, acid solution concentration and acid solution density, the conditional formula is: Calculate the amount of acid solution required; where V 酸溶液 is the amount of acid solution required, M 酸溶液 is the molar mass of the acid solution, ρ1 is the concentration of the acid solution, ρ2 is the density of the acid solution, is the molar mass of ammonia.

9. The method for determining the impurity ion carrying coefficient in the product gas of urea hydrolysis to produce ammonia according to claim 1, characterized in that: The acid solution includes a nitric acid solution.

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