Online concentration detection method for concentrated sulfuric acid

Abstract

The invention relates to the field of concentration detection, and provides an online concentration detection method for concentrated sulfuric acid in order to improve the sulfuric acid concentration detection efficiency in the production process. The relationship between the sulfuric acid density at different temperatures and the sulfuric acid concentration at the standard temperature is established, in the actual production process, the corresponding concentration can be quickly obtained only by detecting the density and the temperature of the sulfuric acid to be detected, the use is convenient, and the detection efficiency is higher.

Description

Technical Field

[0001] The invention relates to the field of concentration detection, in particular to an online concentration detection method for concentrated sulfuric acid. Background Art

[0002] Nitrocellulose is mainly made from refined cotton and nitric acid and sulfuric acid. After refined cotton and nitric acid and sulfuric acid are nitrated together in a nitrifying machine, a centrifuge is used to drive out the waste acid in the nitrocellulose. The waste acid is sent to the acid preparation process, and the replacement acid is sent to the waste acid treatment process to refine and concentrate nitric acid and sulfuric acid respectively. The qualified 98% nitric acid (fuming nitric acid) is transported to the nitric acid storage area to provide raw nitric acid for the nitrocellulose production line; the concentrated 88% sulfuric acid is then added to the sulfuric acid absorption liquid to contact with the SO3 gas generated by sulfur combustion and catalytic conversion in countercurrent, and the 88% sulfuric acid is further concentrated into 98% sulfuric acid or fuming sulfuric acid through chemical absorption, and then transported to the sulfuric acid tank area to provide raw sulfuric acid for the nitrocellulose production line or as a product for export. At present, the waste acid treatment production line recycles 88% sulfuric acid by manual sampling and offline analysis. The whole process is time-consuming, and the on-site environment is not friendly to the human body, the operation process has safety hazards, and it cannot guide production efficiently. Summary of the invention

[0003] In order to improve the efficiency of sulfuric acid concentration detection during the production process, the present application provides an online concentration detection method for concentrated sulfuric acid.

[0004] The technical solution adopted by the present invention to solve the above problems is:

[0005] The method for online detection of the concentration of concentrated sulfuric acid includes:

[0006] Step 1, obtaining the corresponding relationship between sulfuric acid density and temperature and the relationship between sulfuric acid density and concentration at standard temperature;

[0007] Step 2, detecting the temperature of the sulfuric acid to be measured by a temperature sensor, and detecting the density of the sulfuric acid to be measured by a density meter;

[0008] Step 3: based on the corresponding relationship between the density of sulfuric acid and the temperature, the density of the sulfuric acid to be measured is converted into the density at the standard temperature;

[0009] Step 4: Obtain the concentration of the sulfuric acid to be measured based on the relationship between the density and concentration of sulfuric acid at standard temperature.

[0010] Furthermore, the densitometer is a U-tube densitometer.

[0011] Further, the standard temperature is 20°C.

[0012] Compared with the prior art, the present invention has the following beneficial effects: by establishing the corresponding relationship between the density of sulfuric acid and the temperature and the relationship between the density of sulfuric acid and the concentration at the standard temperature, the density of sulfuric acid at different temperatures is linked to the concentration of sulfuric acid at the standard temperature; in the actual production process, only the density and temperature of the sulfuric acid to be tested need to be tested to quickly obtain the corresponding concentration; the invention is easy to use and has higher detection efficiency. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] The method for online detection of the concentration of concentrated sulfuric acid includes:

[0015] Step 1, obtaining the corresponding relationship between the density of sulfuric acid and temperature and the relationship between the density of sulfuric acid and concentration at standard temperature; the relationship between the density of sulfuric acid and concentration at standard temperature can be obtained by detecting the density of sulfuric acid of known concentration at standard temperature, such as detecting the density of sulfuric acid of different concentrations at 20 degrees Celsius. The corresponding relationship between the density of sulfuric acid and temperature can be obtained by obtaining the density change of sulfuric acid of known density at standard temperature at different temperatures.

[0016] Step 2: Detect the temperature of the sulfuric acid to be measured by a temperature sensor, and detect the density of the sulfuric acid to be measured by a density meter; in this embodiment, in order to facilitate the detection of the density of sulfuric acid during the working process, a U-tube density meter is used.

[0017] Step 3: based on the corresponding relationship between the density of sulfuric acid and the temperature, the density of the sulfuric acid to be measured is converted into the density at the standard temperature;

[0018] Step 4: Obtain the concentration of the sulfuric acid to be measured based on the relationship between the density and concentration of sulfuric acid at standard temperature.

[0019] The concentration obtained by the conversion method of the present application and the concentration determined by the chemical titration method can satisfy an absolute error of ≤0.5% in 98.67% of the samples. Therefore, the online detection of sulfuric acid concentration has good accuracy and meets the process requirements.

Claims

1. A method for online detection of the concentration of concentrated sulfuric acid, characterized in that: include: Step 1, obtaining the corresponding relationship between sulfuric acid density and temperature and the relationship between sulfuric acid density and concentration at standard temperature; Step 2, detecting the temperature of the sulfuric acid to be measured by a temperature sensor, and detecting the density of the sulfuric acid to be measured by a density meter; Step 3: based on the corresponding relationship between the density of sulfuric acid and the temperature, the density of the sulfuric acid to be measured is converted into the density at the standard temperature; Step 4: Obtain the concentration of the sulfuric acid to be measured based on the relationship between the density and concentration of sulfuric acid at standard temperature.

2. The method for online detection of the concentration of concentrated sulfuric acid according to claim 1, characterized in that: The densitometer is a U-tube densitometer.

3. The method for online detection of the concentration of concentrated sulfuric acid according to claim 1, characterized in that: The standard temperature is 20℃.