阅读说明：本技术 一种在线测量氨水钠含量的装置及方法 (Device and method for online measurement of sodium content in ammonia water ) 是由 周潮 华若岚 刘宏侠 李强 白阳晨 翟宏升 闫敏 谭娟 于 2021-02-25 设计创作，主要内容包括：本发明公开的一种在线测量氨水钠含量的装置及方法,该装置包括在线钠表、在线钠表流量计、进水管、加药泵出口流量计、加药泵、出气管、洗气瓶和进气管,该方法采用动态在线测量方式,先测量纯水溶剂的钠离子质量浓度,用纯水将氨水稀释成一定比例的溶液,该氨溶液用加药泵加入到纯水中,稀释氨溶液,调节泵的出力,将氨水浓度稀释到一个合理的范围内,降低了铵根离子浓度,使铵根离子对钠离子测量影响忽略不计,稀释后的氨溶液依次进入钠表流量计和在线钠表,测量钠离子质量浓度。根据稀释氨溶液钠离子质量浓度、纯水溶剂钠离子质量浓度、加药泵出口流量值和在线钠表的流量值确定氨水的钠含量,该方法能快速准确地测量出氨水的钠含量,具有较高的使用价值和推广价值。(The invention discloses a device and a method for online measuring the sodium content of ammonia water, wherein the device comprises an online sodium meter, an online sodium meter flowmeter, a water inlet pipe, a dosing pump outlet flowmeter, a dosing pump, a gas outlet pipe, a gas washing bottle and a gas inlet pipe. The method can quickly and accurately measure the sodium content of the ammonia water, and has high use value and popularization value.)

1. A device for measuring the content of ammonia water sodium on line is characterized by comprising an on-line sodium meter (1), a sodium meter flowmeter (2), a dosing pump outlet flowmeter (4), a dosing pump (5) and a dosing bottle (6);

the water inlet of online sodium table (1) is connected the delivery port of sodium table flowmeter (2), and the water source is connected respectively to the water inlet of sodium table flowmeter (2) and adds medicine pump export flowmeter (4), adds medicine pump export flowmeter (4) and is connected with medicine bottle (6) through adding medicine pump (5), adds medicine bottle (6) and connects purifier, has filled aqueous ammonia solution in adding medicine bottle (6).

2. The device for on-line measurement of ammonia water sodium content according to claim 1, characterized in that purifier includes gas washing bottle (8), and the oral area of gas washing bottle (8) sets up outlet duct (7) and intake pipe (9), and the one end and the gas washing bottle (8) of intake pipe (9) communicate, and the other end is located the outside of gas washing bottle (8), and the one end and the gas washing bottle (8) of outlet duct (7) communicate, and the other end and the medicine bottle (6) of outlet duct (7) are connected.

3. The device for on-line measurement of the content of ammonia water and sodium according to claim 2, characterized in that the gas washing bottle (8) is filled with liquid, the end of the gas inlet pipe (9) extends into the liquid, and the end of the gas outlet pipe (7) is located above the water level of the liquid.

4. The device for on-line measurement of the content of the sodium ammonia in the ammonia water of claim 3, wherein the liquid is pure water.

5. The device for on-line measurement of ammonia water sodium content of claim 2, characterized in that the mouth parts of the gas washing bottle and the dosing bottle are provided with sealing structures, and the two ends of the gas outlet pipe and the gas inlet pipe are communicated with the gas washing bottle and the dosing bottle through the sealing structures.

6. The device for on-line measurement of the content of the sodium in the ammonia water as claimed in claim 1, wherein the water source is pure water, and the water inlet of the sodium meter flowmeter (2) is connected with a water purifier.

7. The device for on-line measurement of the content of the sodium ammonia in the ammonia water of claim 1, wherein the purification device is an air filter.

8. A measuring method of the device for on-line measuring the content of the ammonia water sodium according to any one of claims 1 to 7, characterized by comprising the following steps:

step 1, introducing pure water into an online sodium meter to obtain the sodium mass concentration C of the pure water₁；

Step 2, taking V₁A volume of ammonia water is added to V₂Preparing ammonia solution with a certain proportion in pure water with a certain volume, and pouring the ammonia solution into a medicine adding bottle;

step 3, starting a dosing pump to mix the ammonia solution in the dosing bottle with pure water to dilute the ammonia solution, wherein the diluted ammonia solution sequentially passes through a sodium meter flowmeter (2) and an online sodium meter (1), and the flow Q of a dosing pump outlet flowmeter (4) is obtained₁Flow rate Q of sodium meter flowmeter₂And sodium mass concentration C₂；

Step 4, according to the sodium mass concentration C of the pure water₁Sodium mass concentration C₂And the flow rate Q of the outlet flowmeter (4) of the dosing pump₁And flow rate Q of sodium meter flowmeter₂And determining the sodium mass fraction W of the ammonia water.

9. The method for measuring the device for on-line measurement of the sodium content of ammonia water as claimed in claim 8, wherein in the step 2, the ammonia water and the pure water are mixed according to a volume ratio of 1 (500-1000) to form the ammonia solution.

10. The method for measuring the device for on-line measuring the content of the sodium in the ammonia water as claimed in claim 8, wherein the method for determining the sodium mass fraction W of the ammonia water in the step 4 is as follows:

wherein ρ is the density of ammonia water.

Technical Field

The invention relates to the field of power plant on-line chemical instrument measurement, in particular to a device and a method for measuring the content of ammonia water and sodium on line.

Background

The alkalizer used in the thermal power plant to adjust the feed water pH is generally ammonia (NH)₃). The essence of the feed water ammoniating treatment is to neutralize the free carbon dioxide in the feed water with ammonia and alkalize the medium, raise the pH of the feed water to a specified value, and control the corrosion rate of steel and copper alloy materials in the feed water system within a low range to ensure that the iron and copper contents meet specified standards. The ammonia is added into the water in an ammonia water mode, and the sodium content of the ammonia water is strictly controlled, so that the sodium content meets the standard specified in the national standard GB/T631-2007 chemical reagent ammonia water. If the sodium content in the ammonia water exceeds the standard, the sodium content of a thermodynamic system exceeds the standard, and sodium salt deposition can happen to a superheater and a steam turbine. Therefore, the method for rapidly and accurately measuring the sodium content of the ammonia water has important significance for safe and economic operation of a unit.

At present, the ammonia water sodium measurement mainly adopts an off-line measurement mode, and the measurement requires a certain time for electrode response, so that the measurement accuracy of sodium ions is poor due to the influence of potassium ions seeped from a reference electrode and dust in air, and the interference of the dissolution of a sodium electrode under the high pH value measurement condition. At the same time, the sodium electrode is coupled to the ammonium ion (NH)₄ ⁺) Is selective for sodium ion (Na)⁺) 0.01 times of the amount of the ammonia water, and the concentration of ammonium ions in the ammonia water is extremely high, so that a great measurement error is caused if the sodium content of the ammonia water is directly measured on an online sodium meter.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a device and a method for measuring the content of ammonia water sodium on line, which adopt a dynamic on-line measuring mode; the ammonia water concentration is diluted to a reasonable range, the ammonium ion concentration is reduced, the influence of the ammonium ions on the sodium ion measurement is ignored, and the sodium content of the ammonia water can be quickly and accurately measured.

The invention is realized by the following technical scheme:

a device for measuring the content of sodium in ammonia water on line comprises an on-line sodium meter, a sodium meter flowmeter, a dosing pump outlet flowmeter, a dosing pump and a dosing bottle;

the water inlet of the on-line sodium meter is connected with the water outlet of the sodium meter flowmeter, the water inlet of the sodium meter flowmeter is respectively connected with the water source and the dosing pump outlet flowmeter, the dosing pump outlet flowmeter is connected with the dosing bottle through the dosing pump, the dosing bottle is connected with the purifying device, and the dosing bottle is filled with ammonia water solution.

Preferably, purifier includes the gas washing bottle, and the oral area of gas washing bottle sets up outlet duct and intake pipe, and the one end and the gas washing bottle intercommunication of intake pipe, the other end are located the outside of gas washing bottle, and the one end and the gas washing bottle intercommunication of outlet duct, the other end and the medicine bottle connection of adding of outlet duct.

Preferably, the gas washing bottle is filled with liquid, the end part of the gas inlet pipe extends into the liquid, and the end part of the gas outlet pipe is positioned above the water level line of the liquid.

Preferably, the liquid is pure water.

Preferably, sealing structures are arranged at the openings of the gas washing bottle and the dosing bottle, and the two ends of the gas outlet pipe and the gas inlet pipe are communicated with the gas washing bottle and the dosing bottle through the sealing structures.

Preferably, the water source is pure water, and a water inlet of the sodium meter flowmeter is connected with the pure water machine.

Preferably, the purification device is an air filter.

A measuring method of a device for measuring the content of sodium in ammonia water on line comprises the following steps:

step 1, introducing pure water into an online sodium meter to obtain the sodium mass concentration C of the pure water₁；

Step 2, taking V₁A volume of ammonia water is added to V₂Preparing ammonia solution with a certain proportion in pure water with a certain volume, and pouring the ammonia solution into a medicine adding bottle;

step 3, starting the dosing pump to mix the ammonia solution in the dosing bottle with pure water to dilute the ammonia solution, and enabling the diluted ammonia solution to sequentially pass through a sodium meter flowmeter and an online sodium meter to obtain the flow Q of an outlet flowmeter of the dosing pump₁Flow rate Q of sodium meter flowmeter₂And sodium mass concentration C₂；

Step 4, according to the sodium mass concentration C of the pure water₁Sodium mass concentration C₂And the flow rate Q of the outlet flowmeter of the dosing pump₁And flow rate Q of sodium meter flowmeter₂And determining the sodium mass fraction W of the ammonia water.

Preferably, the ammonia water and the pure water in the step 2 are mixed according to the volume ratio of 1 (500-1000) to form an ammonia solution.

Preferably, the method for determining the sodium mass fraction W of the ammonia water in step 4 is as follows:

wherein ρ is the density of ammonia water.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a device for measuring the content of sodium in ammonia water on line, which adopts a dynamic on-line measuring mode, potassium ions seeped out from a reference electrode can not interfere with measurement, a sodium electrode can not be dissolved under the condition of high pH value measurement, and the measurement can not be interfered.

Drawings

FIG. 1 is a schematic structural diagram of the apparatus for measuring sodium content in ammonia water according to the present invention.

In the figure: 1. the system comprises an online sodium meter, 2 sodium meter flow meters, 3 water inlet pipes, 4 dosing pump outlet flow meters, 5 dosing pumps, 6 dosing bottles, 7 air outlet pipes, 8 gas washing bottles, 9 air inlet pipes.

Detailed Description

The present invention will now be described in further detail with reference to the attached drawings, which are illustrative, but not limiting, of the present invention.

Referring to fig. 1, the device for measuring the content of sodium in ammonia water on line comprises an on-line sodium meter 1, a sodium meter flowmeter 2, a dosing pump outlet flowmeter 4, a dosing pump 5 and a dosing bottle 6.

Wherein, the export of sodium meter flowmeter 2 is connected to online sodium meter 1's water inlet, and the water source is connected respectively to sodium meter flowmeter 2's entry and medicine pump outlet flow meter 4, and medicine pump outlet flow meter 4 is connected with medicine bottle 6 through adding medicine pump 5, adds medicine bottle 6 and connects purifier, is filled with the ammonia solution in the medicine bottle 6.

Above-mentioned purifier includes gas washing bottle 8, its inside filling pure water, and gas washing bottle 8's oral area sets up outlet duct 7 and intake pipe 9, and the one end of intake pipe 9 stretches into to the pure water in, and the other end is located gas washing bottle 8's outside, and the one end of outlet duct 7 stretches into to gas washing bottle 8 to be located more than the water level line of pure water, the other end and the medicine bottle 6 that adds of outlet duct 7 are connected.

When the dosing pump works, the ammonia solution in the dosing bottle 6 is sucked out by using negative pressure, so that in order to avoid that air which is not purified outside enters the dosing bottle 6, a sealing structure is arranged at the opening part of the dosing bottle, the air can only enter through a gas washing bottle and is purified by pure water, and the purified air is sucked into the dosing bottle under the action of the negative pressure, so that the influence of sodium ions in the air dissolved in the ammonia solution on the measurement result is avoided; secondly, in order to avoid air from entering the air outlet pipe through pure water, a sealing structure is arranged at the opening part of the gas washing bottle, so that air can only enter the pure water through the air inlet pipe 9, and further the air purification is realized.

The sodium meter flowmeter is connected to a water purifier through a water inlet pipe 3, and pure water produced by the water purifier is introduced into the sodium meter flowmeter 2 and the on-line sodium meter 1, and is used for diluting the ammonia solution.

Sealing structures are arranged at the mouth parts of the gas washing bottle 8 and the dosing bottle 6, and the two ends of the gas outlet pipe 7 and the gas inlet pipe 9 are connected with the gas washing bottle 8 and the dosing bottle 6 through the sealing structures, so that dust can be prevented from entering the dosing bottle, sodium ions in the dust are prevented from influencing a measuring result, and measuring precision is improved.

The sealing structure is an elastic sealing plug made of rubber or silica gel.

In another embodiment, air is filtered using a gas filter that is connected to the applicator bottle 6 via tubing.

The following detailed description is provided for a measuring method of the device for measuring the content of the ammonia water sodium on line, and the method comprises the following steps:

step 1, introducing pure water into an online sodium meter, and recording the sodium mass concentration C of the pure water after a measured value is stable₁。

And 2, pouring a certain amount of pure water into the gas washing bottle to clean dust in the air entering the dosing bottle.

Step 3, taking V₁A volume of ammonia water is added to V₂The ammonia solution is diluted by preparing a certain proportion of ammonia solution in pure water with a certain volume, and the ammonia solution is poured into a medicine adding bottle.

And (2) mixing ammonia water and pure water according to the volume ratio of 1 (500-1000) to form an ammonia solution.

Step 4, starting a dosing pump to mix the ammonia solution in the dosing bottle with pure water to dilute the ammonia solution prepared in the step 3, wherein the diluted ammonia solution sequentially passes through a sodium meter flowmeter 2 and an online sodium meter 1, and the flow Q of the dosing pump outlet flowmeter 4 is recorded₁And flow rate Q of sodium meter flowmeter₂Recording the sodium mass concentration C after the online sodium meter measured value is stabilized₂。

Specifically, the flow of pure water and the flow of the ammonia solution can be controlled by controlling the flow rate of a water source and the power of a dosing pump, so that the pure water can dilute the ammonia solution prepared in the step 3 to a reasonable range and then pass through a sodium meter flowmeter 2 and an online sodium meter 1.

Step 5, according to the sodium mass concentration C of the pure water₁Sodium mass concentration C₂And the flow rate Q of the outlet flow meter 4 of the dosing pump₁And flow rate Q of sodium meter flowmeter₂Determining the sodium mass fraction W of the ammonia water, and calculating according to the following formula:

wherein ρ is the density of ammonia water.

The measuring method adopts a dynamic online measuring mode, pure water is introduced into an online sodium meter, and after a measured value is stable, the sodium mass concentration C of the pure water is recorded₁Then take V₁A volume of ammonia water is added to V₂In the pure water of volume, with preliminary dilution aqueous ammonia, prepare the ammonia solution of certain proportion, pour into with in the medicine bottle, then, pour into a quantitative pure water into toward the gas washing bottle, start and control the power of dosing pump, add the ammonia solution into the pure water, dilute the ammonia solution, make aqueous ammonia concentration dilute to a reasonable within range, ammonium ion concentration has been reduced, make ammonium ion neglect the influence to sodium ion measurement, make the ammonia solution after diluting pass through sodium meter flowmeter 2 and online sodium meter 1 in proper order, record and add medicine pump outlet flow Q₁And on-line sodium meter flow Q₂Recording the mass concentration C after the online sodium meter measured value is stable₂The dosing pump is characterized in that the dosing pump is provided with a dosing bottle, a gas inlet pipe is arranged on the dosing bottle, the dosing bottle is provided with a gas inlet pipe, the dosing bottle is provided with a gas outlet pipe, the gas inlet pipe is communicated with the gas outlet pipe, the gas outlet pipe is communicated with the gas outlet pipe, and the gas outlet pipe is communicated with the gas inlet pipe.

Step 3V₁A volume of ammonia water is added to V₂Preparing ammonia solution with a certain proportion in pure water, wherein the mass concentration of sodium in the ammonia solution is C₃And the following relation is satisfied within a certain time T:

C₃Q₁T＝(C₂-C₁)Q₂T (1)

and (3) obtaining:

C₃Q₁＝(C₂-C₁)Q₂ (2)

and (3) obtaining:

the mass concentration of sodium in the ammonia water is C_AmmoniaThe following relation is provided with the ammonia solution prepared in the step 3:

C₃(V₁+V₂)＝C_ammoniaV₁+C₁V₂ (4)

And (3) obtaining:

substituting (3) into (5) to obtain ammonia water mass concentration C_Ammonia：

And when the density of the ammonia water is rho, the sodium mass fraction W of the ammonia water is as follows:

substituting (6) into (7) to obtain the mass fraction W of ammonia sodium:

taking the measurement and analysis of pure ammonia water as an example, the measurement results of the method are shown in table 1.

TABLE 1 measurement results

The sodium index in the national standard GB/T631-2007 chemical reagent ammonia water is as follows: the mass fraction of sodium is less than or equal to 0.0005 percent, and the mass fraction of sodium is less than 0.0005 percent when the method is used for measuring the sodium content of analytically pure ammonia water.

The invention adopts a dynamic online measurement mode, potassium ions seeped out of the reference electrode cannot interfere with measurement, and the sodium electrode cannot be dissolved under the high pH value measurement condition, so that the measurement cannot be interfered. The method dilutes the concentration of ammonia water to a reasonable range, reduces the concentration of ammonium ions, and ignores the influence of the ammonium ions on the measurement of sodium ions. And (4) feeding diluted ammonia water into an online sodium meter, and measuring the mass concentration of sodium ions. And calculating the sodium content of the ammonia water according to the mass concentration of sodium ions in the diluted ammonia water, the mass concentration of sodium ions in the pure water solvent, the outlet flow value of the dosing pump and the flow value of an online sodium meter. The method can quickly and accurately measure the sodium content of the ammonia water, and the method also eliminates the sodium content of the pure water solvent, so that the measurement is more accurate. Therefore, the measuring method can quickly and accurately measure the content of the ammonia water sodium, and is particularly suitable for being used in a production field.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.