阅读说明：本技术 一种热分解含氨化合物产氨气的方法及装置 (Method and device for producing ammonia gas by thermally decomposing ammonia-containing compound ) 是由 关家彬 蒋一峰 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种热分解含氨化合物产氨气的方法及装置,热分解含氨化合物产氨气的装置包括反应装置、吸收缸,反应装置包括加热锅以及冷凝回流装置,吸收缸上方设置有射流器,吸收缸底部一侧设置有出液口,所述出液口通过弯管连接有磁力泵,所述磁力泵上连接有两个球阀,分别为出水球阀及回流球阀,所述回流球阀的另一端连接有冷凝桶,所述冷凝桶与所述射流器的进液口通过直角管道连接。本发明通过使用上述装置热分解氨水或氨盐的方式制造氨气,用再生液作为氨气的溶剂,能有效提高再生液的pH,且因为再生液只吸收了氨气,再生液几乎没有体积变化。(The invention discloses a method and a device for thermally decomposing ammonia containing compounds to produce ammonia, wherein the device for thermally decomposing ammonia containing compounds to produce ammonia comprises a reaction device and an absorption cylinder, the reaction device comprises a heating pot and a condensation reflux device, an ejector is arranged above the absorption cylinder, a liquid outlet is arranged on one side of the bottom of the absorption cylinder, the liquid outlet is connected with a magnetic pump through a bent pipe, the magnetic pump is connected with two ball valves which are a water outlet ball valve and a reflux ball valve respectively, the other end of the reflux ball valve is connected with a condensation barrel, and the condensation barrel is connected with a liquid inlet of the ejector through a right-angle pipeline. The device is used for preparing ammonia gas by thermally decomposing ammonia water or ammonia salt, the regenerated liquid is used as a solvent of the ammonia gas, the pH value of the regenerated liquid can be effectively increased, and the regenerated liquid only absorbs the ammonia gas and hardly has volume change.)

1. Device for producing ammonia gas by thermally decomposing ammonia-containing compound, which is characterized by comprising a reaction device and an absorption cylinder (2), wherein the reaction device comprises a heating pot (1) and a condensation reflux device (3) arranged above the heating pot (1), a sealed water-separating barrel (5) is arranged between the heating pot (1) and the absorption cylinder (2), an ammonia inlet and an ammonia outlet are arranged at the upper end of the sealed water-separating barrel (5), an air inlet pipe (51) is connected between the heating pot (1) and the sealed water-separating barrel (5), an air outlet pipe (52) is connected between the absorption cylinder (2) and the sealed water-separating barrel (5), the air inlet pipe (51) is connected with the ammonia inlet, the air outlet pipe (52) is connected with the ammonia outlet, the air outlet pipe (52) extends into the bottom of the sealed water-separating barrel, and the pipe orifice height of the air inlet pipe (51) is higher than that of the air outlet pipe (52), an ejector (4) is arranged above the absorption cylinder (2), the air outlet pipe (52) is connected with a suction inlet of the ejector (4), a sealing cover (6) is arranged above the absorption cylinder (2), a liquid outlet is arranged at one side of the bottom of the absorption cylinder (2), the liquid outlet is connected with a magnetic pump (7) through an elbow, the magnetic pump (7) is connected with two ball valves which are a water outlet ball valve (71) and a return ball valve (72) respectively, the other end of the backflow ball valve (72) is connected with a condensation barrel (8), the condensation barrel (8) is connected with a liquid inlet of the ejector (4) through a right-angle pipeline (81), be provided with cold water pipe (82) in condensation bucket (8), be provided with flowmeter (9) between right angle pipeline (81) and condensation bucket (8), be provided with valve (91) of control flow rate on flowmeter (9).

2. The apparatus for thermally decomposing an ammonia-containing compound to produce ammonia according to claim 1, wherein: the heating pot is characterized in that an installation base (11) is arranged at the bottom of the heating pot (1), three heating pipes (12) are arranged in the heating pot (1), and a negative pressure gauge (14) and a first thermometer (13) are arranged above the heating pot (1).

3. The apparatus for thermally decomposing an ammonia-containing compound to produce ammonia according to claim 1, wherein: a regeneration liquid inlet is arranged above the sealing cover (6) and connected with a regeneration liquid inlet pipeline (10).

4. The apparatus for thermally decomposing an ammonia-containing compound to produce ammonia according to claim 1, wherein: and a pressure gauge (61) is arranged above the sealing cover (6).

5. The apparatus for thermally decomposing an ammonia-containing compound to produce ammonia according to claim 1, wherein: ejector (4) with absorption jar (2) are connected through first PVC pipe (21), first PVC pipe (21) extend to absorption jar (2) bottom, the vertical articulate of first PVC pipe (21) and five-way pipe (22), four transverse joint of five-way pipe (22) are through second PVC pipe (23) connection a plurality of sprayer (24).

6. The apparatus for thermally decomposing an ammonia-containing compound to produce ammonia according to claim 1, wherein: the condensing barrel (8) is provided with a pH probe (83) and a second thermometer (84).

7. A method for thermally decomposing an ammonia-containing compound to produce ammonia gas, characterized by using the apparatus for thermally decomposing an ammonia-containing compound to produce ammonia gas according to any one of claims 1 to 5, comprising the steps of:

s1: adding any one of an ammonia-containing compound, ammonium salt or ammonia water into a heating pot, wherein high-concentration sodium hydroxide solution is required to be added in advance when the ammonium salt is heated;

s2: adding alkaline regeneration liquid into an absorption cylinder in advance;

s3: connecting all parts of the device;

s4: starting a reaction device to promote the reaction of ammonium salt and ammonia water; and the volatilized ammonia gas is introduced into the absorption cylinder through the ejector.

8. The method for producing ammonia gas by thermal decomposition of an ammonia-containing compound according to claim 7, wherein the temperature of the regenerating liquid in the heating pot is controlled within a range of 25 ± 2 ℃.

9. The method for producing ammonia gas by thermal decomposition of an ammonia-containing compound according to claim 7, wherein the ammonia water or the ammonium salt in step S1 has an ammonia content of 6 mol/L.

10. The method for producing ammonia gas by thermal decomposition of an ammonia-containing compound according to claim 7, wherein the reaction time in step S4 is 3 to 4 hours.

Technical Field

The invention relates to the technical field of electrolysis, in particular to a method and a device for producing ammonia gas by thermally decomposing ammonia-containing compounds.

Background

Etching copper is an important step in the manufacturing process of PCB boards. Currently, the etching solution used for etching copper mainly includes acidic etching solution (mainly containing copper chloride, hydrochloric acid and ammonium chloride) and alkaline etching solution (mainly containing copper chloride,ammonia water and ammonium chloride), a large amount of waste etching solution is generated after etching is finished, and because the waste etching solution contains a large amount of heavy metal copper ions and acid and alkali, if the waste etching solution is directly discharged into the environment, the ecological environment is seriously damaged, so that the recycling of the etching solution after etching is very important. Taking an alkaline etching solution as an example, when the etching solution etches a PCB, the reaction occurs: cu + Cu (NH)₃) ₄Cl₂→ 2Cu ( NH₃ ) ₂And Cl, dissolving copper on the PCB by the etching solution through oxidation, dissolution and matching processes to increase the copper content in the etching solution, wherein in the conventional etching solution regeneration process, a solvent extraction method is generally adopted, namely copper ions in the etching solution are extracted into an extractant, the extractant is subjected to back extraction by using a sulfuric acid solution, and a copper sulfate solution is formed and then is electrolyzed to obtain the elemental copper with high purity. After the copper content of the etching solution (also called as regeneration solution) extracted by the extractant is reduced, ammonia water and ammonium chloride are added to supplement the ammonia content (namely, the pH value of the solution is increased) and chloride ions, and the regeneration solution formed after regeneration can be returned to the etching machine to be used as the etching solution for continuous use.

As can be understood from the above, after the alkaline etching solution is etched and extracted, the ammonia content of the alkaline etching solution is reduced, so to supplement ammonia, a large amount of ammonia water or liquid ammonia needs to be added to increase the pH, but a large amount of moisture is also brought in while the ammonia water is added, so that the volume of the regenerated solution is increased, the concentration of relevant ions is diluted, and at this time, a relevant supplement agent needs to be added. Although the increment problem of the etching liquid can be solved by the liquid ammonia, the transportation of the liquid ammonia is difficult.

Disclosure of Invention

The invention aims to provide a method for producing ammonia gas by thermally decomposing an ammonia-containing compound and design a corresponding device, and the method is used for conveying the produced ammonia gas into a regenerated liquid through an ejector by thermally decomposing the ammonia-containing compound so as to solve the increment problem caused by directly adding ammonia water.

The technical scheme of the invention is as follows:

a device for producing ammonia gas by thermally decomposing ammonia-containing compounds is characterized by comprising a reaction device and an absorption cylinder, wherein the reaction device comprises a heating pot and a condensation reflux device arranged above the heating pot, a sealed water-separating barrel is arranged between the heating pot and the absorption cylinder, an ammonia inlet and an ammonia outlet are arranged at the upper end of the sealed water-separating barrel, an air inlet pipe is connected between the heating pot and the sealed water-separating barrel, an air outlet pipe is connected between the absorption cylinder and the sealed water-separating barrel, the air inlet pipe is connected with the ammonia inlet, the air outlet pipe is connected with the ammonia outlet, the air outlet pipe extends into the bottom of the sealed water-separating barrel, the pipe orifice height of the air inlet pipe is higher than that of the air outlet pipe, an ejector is arranged above the absorption cylinder, the air outlet pipe is connected with the suction inlet of the ejector, a sealed cover is arranged above the absorption cylinder, and a liquid outlet is arranged on one side of the bottom of the absorption cylinder, the liquid outlet has the magnetic drive pump through the return bend connection, be connected with two ball valves on the magnetic drive pump, be play water ball valve and backward flow ball valve respectively, the other end of backward flow ball valve is connected with the condensation bucket, the condensation bucket with the inlet of ejector passes through right angle pipe connection, be provided with the cold water pipe in the condensation bucket, be provided with the flowmeter between right angle pipe and the condensation bucket, be provided with the valve of the control flow rate on the flowmeter.

Further, the bottom of the heating pot is provided with an installation base, three heating pipes are arranged in the heating pot, and a negative pressure gauge and a first thermometer are arranged above the heating pot.

Further, a regeneration liquid inlet is arranged above the sealing cover and connected with a regeneration liquid inlet pipeline.

Further, a pressure gauge is arranged above the sealing cover and used for measuring the pressure in the absorption cylinder.

Further, the ejector with the absorption jar passes through first PVC union coupling, first PVC pipe extends to the absorption jar bottom, the vertical articulate of first PVC pipe and five-way pipe, four transverse joint of five-way pipe pass through a plurality of sprayer of second PVC union coupling, the effect of sprayer makes the ammonia that gets into the absorption jar can fully contact with the regeneration liquid.

Further, a pH probe and a second thermometer are arranged on the condensation barrel, the pH probe is used for measuring the pH of the regenerated liquid in the absorption cylinder, and the second thermometer is used for measuring the temperature of the regenerated liquid in the absorption cylinder.

The invention also discloses a method for thermally decomposing ammonia-containing compounds to produce ammonia gas, and the device for thermally decomposing ammonia-containing compounds to produce ammonia gas comprises the following specific steps:

s1: adding any one of an ammonia-containing compound, ammonium salt or ammonia water into a heating pot, wherein high-concentration sodium hydroxide solution is required to be added in advance when the ammonium salt is heated;

s2: adding alkaline regeneration liquid into an absorption cylinder in advance;

s3: connecting all parts of the device;

s4: starting a reaction device to promote the reaction of ammonium salt and ammonia water; and the volatilized ammonia gas is introduced into the absorption cylinder through the ejector.

Further, the temperature of the regeneration liquid in the heating pot is controlled within the range of 25 +/-2 ℃.

Further, the ammonia content of the ammonia water and the ammonium salt in the step S1 is 6 mol/L.

Further, the reaction time in the step S4 is 3 to 4 hours.

The working principle is as follows: ammonia gas is produced by thermal decomposition of ammonia water or an ammonia salt, and the regenerated liquid is used as a solvent for ammonia gas. Ammonium carbamate or other ammonium salts (such as ammonium chloride, ammonium bicarbonate and the like) are added into a heating pot, a catalyst, a solution and the like can be added when needed, the ammonium carbamate is promoted to be decomposed by heating (electric heating, oil bath and the like), a condensation reflux device is arranged above the heating pot, ammonia gas generated in the heating pot is connected to a suction inlet of an ejector through a sealed water-separating barrel, and a cold flow reflux device can prevent water vapor from entering the ejector so as to ensure that only the ammonia gas passes through a communicated pipeline. The ejector arranged on the absorption cylinder and the magnetic pump arranged on one side of the bottom of the absorption cylinder enable water flow in the ejector to be regenerated liquid, and the vacuum generated by the ejector is utilized to suck ammonia gas generated in the heating pot. During the reaction of the ammonium carbamate and the ammonia gas, carbon dioxide can be generated besides the required ammonia gas, and the carbon dioxide is very easy to dissolve in alkaline solution, including alkaline etching solution and ammonia water, so that the pH value in the absorption cylinder cannot be increased, and the use is influenced, so that alkaline substances are added to remove the carbon dioxide, and the carbon dioxide is prevented from entering the absorption cylinder.

Ammonia-generating compounds in addition to ammonium carbamate, ammonia gas can also be generated by the thermal decomposition of other ammonium salts, such as ammonium bicarbonate and ammonium carbonate. Taking ammonium bicarbonate as an example, the reaction occurs during heating:

NH₄HCO₃==NH₃↑+H₂O+CO₂↑

in order to make CO generated by the reaction₂The sodium hydroxide solution is added into the generating device in advance without entering into the regenerated etching solution, and then the reaction is carried out: 2NaOH + NH₄HCO₃=Na₂CO₃+2H₂O+NH₃

For Na formed by reaction₂CO₃Sodium hydroxide, which can be recycled, can be converted by adding less costly calcium oxide, and the reaction takes place as follows: CaO + H₂O=Na₂CO₃=CaCO₃↓+2NaOH

After the reaction product is filtered, the residual sodium hydroxide solution can continue to react with ammonium bicarbonate to generate ammonia.

The invention has the beneficial effects that:

1. in order to solve the problems that the sublimation and crystallization of ammonium carbamate block pipelines and carbon dioxide generated by thermal decomposition affects the pH of a regeneration liquid, the invention adds a high-concentration sodium hydroxide solution into a heating pot, thereby promoting the generation of ammonia gas and absorbing the carbon dioxide. The ammonia gas generated by the thermal decomposition of the ammonium carbamate can effectively improve the pH value of the regenerated liquid, and the regenerated liquid only absorbs the ammonia gas, so that the regenerated liquid has almost no volume change.

2. Except ammonium carbamate, other ammonia-containing compounds or ammonia water are heated, the ammonia volatilized from the ammonia is introduced into the alkaline regenerated liquid through the ejector, the regenerated liquid can be effectively improved, the amplitude of the pH value is improved without obvious difference compared with the amplitude of the ammonia water which is directly added, and the problem of increment is solved without adding ammonium chloride. Therefore, direct heating of the ammoniacal compound at an elevated pH of the alkaline regenerant can be used instead of direct addition of ammonia.

Drawings

FIG. 1 is a schematic diagram of the apparatus of the present invention;

FIG. 2 is a schematic sectional view of a part of the reaction apparatus and the sealed water-proof barrel according to the present invention;

FIG. 3 is a schematic sectional view of the absorption cylinder and the condensation barrel according to the present invention;

FIG. 4 is a graph of pH as a function of time for a first ammonium carbamate recycle liquor in example 1;

FIG. 5 is a graph showing the pH of the second ammonium carbamate recycle liquor in example 1 as a function of time,

wherein, 1, the heating pot, 11, the installation base, 12, the heating pipe, 13, first thermometer, 14, the barometer, 2, the absorption jar, 21, first PVC pipe, 22, the five-way pipe connects, 23, second PVC pipe, 24, the sprayer, 3, the condensation reflux unit, 4, the ejector, 5, sealed water-proof bucket, 51, the intake pipe, 52, the outlet duct, 6, sealed lid, 61, the manometer, 7, the magnetic drive pump, 71, the ball valve that goes out the water, 72, the backward flow ball valve, 8, the condensation bucket, 81, the right angle pipeline, 82, the cold water pipe, 83, the pH probe, 84, the second thermometer, 9, the flowmeter, 91, the valve, 10, regeneration liquid admission line.

Detailed Description

The invention will be further illustrated and understood by the following non-limiting examples.

A device for producing ammonia gas by thermally decomposing ammonia-containing compounds comprises a reaction device and an absorption cylinder 2, wherein the reaction device comprises a heating pot 1 and a condensation reflux device 3 arranged above the heating pot 1, a sealed water-separating barrel 5 is arranged between the heating pot 1 and the absorption cylinder 2, an ammonia gas inlet and an ammonia gas outlet are arranged at the upper end of the sealed water-separating barrel 5, an air inlet pipe 51 is connected between the heating pot 1 and the sealed water-separating barrel 5, an air outlet pipe 52 is connected between the absorption cylinder 2 and the sealed water-separating barrel 5, the air inlet pipe 51 is connected with the ammonia gas inlet, the air outlet pipe 52 is connected with the ammonia gas outlet, the air outlet pipe 52 extends into the barrel bottom of the sealed water-separating barrel, the height of the pipe orifice of the air inlet pipe 51 is higher than that of the air outlet pipe 52, an ejector 4 is arranged above the absorption cylinder 2, the air outlet pipe 52 is connected with a suction inlet of the ejector 4, a sealing cover 6 is arranged above the absorption cylinder 2, a liquid outlet is arranged at one side of the bottom of the absorption cylinder 2, and the liquid outlet is connected with a magnetic pump 7 through a bent pipe, the magnetic pump 7 is connected with two ball valves, namely a water outlet ball valve 71 and a backflow ball valve 72, the other end of the backflow ball valve 72 is connected with a condensation barrel 8, the condensation barrel 8 is connected with a liquid inlet of the ejector 4 through a right-angle pipeline 81, a cold water pipe 82 is arranged in the condensation barrel 8, a flow meter 9 is arranged between the right-angle pipeline 81 and the condensation barrel 8, and a valve 91 for controlling the flow rate is arranged on the flow meter 9 and can be used for controlling the liquid speed in the pipeline, wherein the control speed range is 0-5000L/H.

The bottom of the heating pot 1 is provided with an installation base 11, three heating pipes 12 are arranged in the heating pot 1, and a negative pressure gauge 14 and a first thermometer 13 are arranged above the heating pot 1.

A regeneration liquid inlet is arranged above the sealing cover 6 and is connected with a regeneration liquid inlet pipeline 10.

A pressure gauge 61 is arranged above the sealing cover 6.

Ejector 4 is connected through first PVC pipe 21 with absorption jar 2, and first PVC pipe 21 extends to absorption jar 2 bottoms, and first PVC pipe 21 and five-way pipe 22's vertical articulate, and four transverse joint of five-way pipe 22 are through second PVC pipe 23 connection a plurality of sprayer 24, and the effect of sprayer 24 makes the ammonia that gets into absorption jar 2 fully contact with the regeneration liquid.

The condensation tank 8 is provided with a pH probe 83 and a second thermometer 84.

The invention discloses a method for thermally decomposing ammonia-containing compound to produce ammonia, which adopts the device for thermally decomposing ammonia-containing compound to produce ammonia and comprises the following steps:

s1: adding high-concentration sodium hydroxide into a heating pot, adding ammonium salt with the ammonia content of 6mol/L,

s2: adding alkaline regeneration liquid into an absorption cylinder in advance;

s3: connecting all parts of the device;

s4: starting a reaction device to promote the reaction of ammonium salt and ammonia water; and the volatilized ammonia gas is introduced into the absorption cylinder through the ejector.

Example 1

240g of ammonium carbamate (containing 6mol of ammonia) is taken to be placed in a heating pot, high-concentration sodium hydroxide is added to the heating pot, then the heating pot is connected with each instrument, the heating pot is started to heat, ammonium salt and ammonia water are promoted to react, alkaline regeneration liquid is added into an absorption cylinder in advance, the temperature of the regeneration liquid in the absorption cylinder is controlled within the range of 25 +/-2 ℃, the regeneration liquid in the absorption cylinder is not replaced, and the heating is carried out twice respectively.

The specific experimental data are as follows:

experimental data of first heating ammonium carbamate into regenerating liquid

The pH of the regenerant over time in this experiment was plotted as shown in FIG. 4.

The regeneration liquid in the absorption cylinder is not replaced, ammonium carbamate is continuously added for heating, and the experimental data are as follows:

experimental data of second heating ammonium carbamate into regenerating liquid

The pH of the regenerant over time in this experiment was plotted as shown in FIG. 5.

From the above data, the pH of the regenerant increased from 8.7 to 9.02 when ammonium carbamate was heated for the first time, which is not much different from that of ammonia water, and the pH increased from 9.07 to 9.62 when ammonium carbamate was heated for the second time, which is higher than that of ammonia water heated directly, i.e., at lower pH, the amplitude of the regenerant increased by heating ammonia water and ammonium carbamate was substantially the same, but at higher pH, the amplitude of the regenerant pH increased by heating ammonium carbamate was higher than that of heating ammonia water. However, alkaline water needs to be added before ammonium carbamate is heated, and the residual alkaline water with higher concentration after heating can be used for treating chlorine gas in an air gasifying tower in an acid recovery system.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way and substantially, and all technical solutions falling within the spirit of the present invention are considered to be within the scope of the present invention.