A Kjeldahl nitrogen determination high-efficiency distillation system, a Kjeldahl nitrogen determination instrument and a distillation method

Abstract

The present invention provides a Kjeldahl nitrogen determination high-efficiency distillation system, a Kjeldahl nitrogen determination instrument and a distillation method, and belongs to the technical field of Kjeldahl nitrogen determination. The present invention proposes for the first time the strategies and corresponding structures of "steady-state flash" (i.e. Steady-Flash) and "green condensation". The superheated steam for heating the reagent in the digestive tube is two streams, which are heated at the top and bottom of the reagent at the same time. The splash-proof bottle has high temperature and low pressure without blind-end pipelines. The condenser relies on air cooling to dissipate heat, and low temperature and low pressure are achieved through "green technology"; the high-temperature reagent in the digestive tube is lifted by steam, and the boiling point is reduced after decompression, and the "flash evaporation" phenomenon continues to occur. While the reagent is stably and accurately distilled, the reagent distillation speed is accelerated, the distillation time is shortened, and the distillation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of Kjeldahl nitrogen determination, proposes "steady-flash" and "green-condense" strategies and corresponding structures, and specifically relates to a Kjeldahl nitrogen determination high-efficiency distillation system, a Kjeldahl nitrogen determination instrument and a distillation method. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] The Kjeldahl method is a method for measuring the protein content in a sample based on nitrogen. It uses concentrated acid to digest the sample, converting all organic nitrogen in the sample into inorganic ammonium salts, and then converting the ammonium salts into ammonia under alkaline conditions. The ammonia is distilled out with water vapor and absorbed by excess acid, and then titrated with standard (concentration) acid. The amount of nitrogen in the sample can be calculated based on the consumed standard (concentration) acid. Since the nitrogen content of protein is relatively constant, the protein content can be calculated from its nitrogen content, so this method is a classic protein quantitative detection method.

[0004] The detection device formed by the above method is a Kjeldahl nitrogen analyzer, which completes the process of distilling ammonia with water vapor through a distillation system. In the distillation system, a steam pipe passes steam into the bottom of the digestive tube to boil the solution to be tested, thereby distilling the ammonia in the solution to be tested in the form of ammonia gas, and then proceeding to the next step of condensation process.

[0005] The inventors found that the existing distillation process has the following problems: (1) The existing technical solution can only produce saturated steam, which is easy to condense and reduce heat, which is not conducive to distillation operation; (2) Steam is only discharged at the bottom of the digestive tract, and the heating efficiency is low; (3) There are many splash-proof bottles and blind-end pipelines in the digestive tract, which have an adverse effect on the accuracy of the test results; (4) Heat can only be dissipated by water cooling, which consumes a lot of cooling water and limits the usage scenarios. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the present invention proposes for the first time the strategies and corresponding structures of "steady-state flash" and "green condensation". The superheated steam for heating the reagents in the digestive tract is in two streams, which heat the top and bottom of the reagents simultaneously. The splash-proof bottle has high temperature and low pressure without blind-end pipelines. The condenser relies on air cooling to dissipate heat, and low temperature and low pressure are achieved through "green technology". The high-temperature reagents in the digestive tract are lifted up by the steam, and the boiling point is reduced after decompression, and the "flash evaporation" phenomenon continues to occur. While the reagents are stably and accurately distilled, the distillation speed of the reagents is accelerated, the distillation time is shortened, and the distillation efficiency is improved.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a Kjeldahl nitrogen determination high-efficiency distillation system.

[0009] A Kjeldahl nitrogen determination high-efficiency distillation system comprises: a steam generator, a digestion tube, a splash-proof bottle and a condenser, wherein the digestion tube is located at the bottom of the splash-proof bottle, the splash-proof bottle is connected to the internal space of the digestion tube, the steam output pipeline of the steam generator is connected to the bottom of the digestion tube through a first pipeline, the first pipeline is connected to a first valve, the steam output pipeline of the steam generator is connected to the splash-proof bottle through a second pipeline, and the second pipeline is connected to a second valve.

[0010] As a further limitation of the first aspect of the present invention, after water enters the steam generator, it passes through the supercooled state, saturated water, gas-liquid two-phase, saturated steam, and superheated steam state in sequence, and then overflows at the bottom of the digestive tract through the first valve, playing a heating and disturbing role;

[0011] The second valve is opened. At this time, the steam at the outlet of the steam generator is divided into two streams. The steam enters the splash-proof bottle through the second valve. The two streams of steam heat and disturb the liquid in the digestion tube and the splash-proof bottle at the same time, thereby improving the heating efficiency, accelerating the precipitation of the target product to be detected, and increasing the distillation rate.

[0012] As a further limitation of the first aspect of the present invention, the splash-proof bottle is connected to the first one-way valve through a pipeline, the first one-way valve is connected to the first liquid pump through a pipeline, and the first liquid pump is used to transport the alkali solution to the digestive tract through the first one-way valve.

[0013] As a further limitation of the first aspect of the present invention, the top of the splash-proof bottle is connected to the condenser through a pipeline, the condenser is connected to the receiving cup through a third valve, the first port of the first three-way valve is used to communicate with the water source, the third port of the first three-way valve is connected to the second liquid pump, and the output port of the second liquid pump is connected to the first port of the second three-way valve;

[0014] The second port of the second three-way valve is connected to the top of the splash-proof bottle through the fourth valve, the third port of the second three-way valve is connected to the second port of the third three-way valve through the fifth valve, and the third port of the third three-way valve is connected to the receiving cup;

[0015] The first port of the third three-way valve is communicated with the second one-way valve, the second one-way valve is communicated with the third liquid pump, and the input port of the third liquid pump is used to receive the acid solution.

[0016] As a further limitation of the first aspect of the present invention, the condenser, the sixth liquid pump, the water tank, the air-cooled radiator and the water-cooled radiator are connected in sequence through pipelines, and the water-cooled radiator is connected to the condenser through a pipeline. The air-cooled radiator can work alone or in conjunction with the water-cooled radiator.

[0017] As a further limitation of the first aspect of the present invention, a fourth three-way valve and a fifth three-way valve are connected between the first valve on the first pipeline and the digestive tract, the first port of the fourth three-way valve is connected to the third one-way valve, and the first port of the fifth three-way valve is connected to the first port of the sixth three-way valve via the sixth valve;

[0018] The second port of the sixth three-way valve is used for waste discharge, the third port of the sixth three-way valve is connected to the fourth one-way valve, the fourth one-way valve is connected to the fourth liquid pump, and the fourth liquid pump is connected to the bottom of the receiving cup through the seventh valve;

[0019] Optionally, a four-way valve is connected between the first valve on the first pipeline and the digestive tract, the first port of the four-way valve is connected to the third one-way valve, and the second port of the four-way valve is connected to the first port of the sixth three-way valve via the sixth valve;

[0020] The second port of the sixth three-way valve is used for waste discharge, the third port of the sixth three-way valve is connected to the fourth one-way valve, the fourth one-way valve is connected to the fourth liquid pump, and the fourth liquid pump is connected to the bottom of the receiving cup through the seventh valve.

[0021] As a further limitation of the first aspect of the present invention, the second port of the first three-way valve is connected to the bottom of the steam generator through the eighth valve and the fifth liquid pump, and a temperature sensor is connected to the steam output pipeline or the steam generator body;

[0022] The junction of the steam output pipeline, the first pipeline and the second pipeline is communicated with the pressure relief valve.

[0023] As a further limitation of the first aspect of the present invention, a fifth one-way valve is connected to the top of the receiving cup.

[0024] In a second aspect, the present invention provides a Kjeldahl nitrogen analyzer, comprising the Kjeldahl nitrogen determination high-efficiency distillation system described in the first aspect of the present invention.

[0025] In a third aspect, the present invention provides a Kjeldahl nitrogen determination efficient distillation method, using the Kjeldahl nitrogen determination efficient distillation system described in the first aspect of the present invention, comprising the following process:

[0026] The process of adding water to the digestive tract: the second liquid pump is turned on, the fourth valve is turned on, and water enters the digestive tract through the second liquid pump and the fourth valve;

[0027] Process of adding alkali into the digestive tube: the first liquid pump is turned on, and the alkali solution enters the digestive tube through the first liquid pump and the first one-way valve;

[0028] The process of adding acid to the receiving cup: the third liquid pump is turned on, and the acid enters the receiving cup through the third liquid pump and the second one-way valve;

[0029] Steam distillation process: the first valve and the eighth valve are opened, the fifth liquid pump is turned on, and water enters the steam generator through the eighth valve and the fifth liquid pump. After the water passes through the supercooled state, saturated water, gas-liquid two-phase, saturated steam, and superheated steam state in turn, it overflows at the bottom of the digestive tract through the first valve, playing a heating and disturbing role; the second valve is opened, and the steam at the outlet of the steam generator is divided into two streams. The steam enters the splash-proof bottle through the second valve. The two streams of steam heat and disturb the liquid in the digestive tract and the splash-proof bottle at the same time, and the liquid vacates and enters the low-pressure area, and the pressure is reduced to cause "flash evaporation", which accelerates the precipitation of the target product to be detected and increases the distillation rate; the condensation system works during the steam distillation process, and the condensate enters the receiving cup through the condenser and the third valve;

[0030] Waste discharge process of digestive tract: the sixth valve is opened, the first valve is closed, and the second valve is opened. Steam enters the splash-proof bottle from the top of the splash-proof bottle. The liquid in the digestive tract is discharged from the system through the sixth valve under the pressure in the bottle. At this time, the third valve is closed.

[0031] The process of adding water to the receiving cup: the second liquid pump is turned on, the fifth valve is turned on, and the water enters the receiving cup through the second liquid pump and the fifth valve;

[0032] Receiving cup waste discharge process: the seventh valve and the fourth liquid pump are opened, and the liquid in the receiving cup is discharged out of the system through the seventh valve, the fourth liquid pump, the fourth check valve and the sixth three-way valve in sequence.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention proposes for the first time the strategies and corresponding structures of "steady-state flash" and "green condensation". The superheated steam for heating the reagents in the digestive tube is in two streams, which heat the top and bottom of the reagents simultaneously. The splash-proof bottle has high temperature and low pressure without blind-end pipelines. The condenser relies on air cooling to dissipate heat, and low temperature and low pressure are achieved through "green technology". The high-temperature reagents in the digestive tube are lifted by steam, and the boiling point is reduced after decompression, and the "flash evaporation" phenomenon continues to occur. While the reagents are stably and accurately distilled, the distillation speed of the reagents is accelerated, the distillation time is shortened, and the distillation efficiency is improved.

[0035] 2. The cooling system of the present invention mainly relies on air cooling to achieve reagent condensation through "green technology". At the same time, the water cooling sub-unit is connected in series, and the cooling effect can be improved through water cooling, avoiding the impact caused by damage to a single refrigeration system.

[0036] 3. The present invention controls the water flow entering the steam generator by detecting the steam temperature at the steam generator outlet (or the temperature of the steam generator itself), ensuring that the steam at the steam generator outlet is superheated steam; a constant flow pump can also be selected for use with a suitable steam generator, so that the steam generator outlet is superheated steam.

[0037] 4. The third one-way valve and the sixth valve of the present invention are in parallel. The third one-way valve is located on the steam pipeline (can be located downstream of the second valve). The splash-proof bottle and the whole formed by the connection with the digestive tube have three inlet and outlet pipelines to the outside, which improves the rectification efficiency.

[0038] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0040] Figure 1 A schematic diagram of a Kjeldahl nitrogen determination high-efficiency distillation system provided by the present invention;

[0041] Among them, 1. the first liquid pump; 2. the second liquid pump; 3. the third liquid pump; 4. the fourth liquid pump; 5. the fifth liquid pump; 6. the sixth liquid pump; 7. the first valve; 8. the second valve; 9. the third valve; 10. the fourth valve; 11. the fifth valve; 12. the sixth valve; 13. the seventh valve; 14. the eighth valve; 15. the first three-way valve; 16. the second three-way valve; 17. the third three-way valve; 18. the fourth three-way valve; 19. the fifth three-way valve; 20. the sixth three-way valve; 21. the pressure relief valve; 22. the steam generator; 23. the temperature sensor; 24. the first one-way valve; 25. the second one-way valve; 26. the third one-way valve; 27. the fourth one-way valve; 28. the splash-proof bottle; 29. ​​the digestive tube; 30. the condenser; 31. the water tank; 32. the air-cooled radiator; 33. the water-cooled radiator; 34. the receiving cup; 35. the fifth one-way valve. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0044] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] Embodiment 1:

[0046] In this implementation, a Kjeldahl nitrogen determination high-efficiency distillation system is proposed. The following is a brief introduction to the technical terms and related concepts involved in this treatment scheme, including:

[0047] Flash is a phenomenon in which a high-pressure saturated liquid enters a relatively low-pressure container and, due to a sudden drop in pressure, the saturated liquid becomes a portion of the saturated vapor and saturated liquid under the container pressure. The boiling point of a substance increases with increasing pressure, and the lower the pressure, the lower the boiling point. This allows the high-pressure and high-temperature fluid to be decompressed to lower its boiling point and enter the "flash zone". At this time, the fluid temperature is higher than the boiling point under the pressure. The fluid boils and vaporizes rapidly in the flash zone, and the two phases are separated. The equipment that vaporizes the fluid is not the flash zone, but the decompression structure. The role of the flash zone is to provide space for rapid gasification of the fluid and gas-liquid separation.

[0048] When water is heated under atmospheric pressure, 100℃ is the highest temperature that liquid water can be allowed under that pressure. Further heating will not increase the temperature of the water, but will only convert it into steam. The heat absorbed by water before it reaches its boiling point is called "sensible heat", or saturated water sensible heat. The heat required to convert saturated water into water vapor under the same atmospheric pressure is called "latent heat". However, if water is pressurized under a certain pressure, the boiling point of water will be higher than 100℃, so more sensible heat is required. The higher the pressure, the higher the boiling point of water and the higher the heat content. When the pressure is reduced, part of the sensible heat is released, and this excess heat will be absorbed in the form of latent heat, causing part of the water to be "flashed" into steam.

[0049] The present invention generates "superheated steam" through a steam generator, and its main functions are:

[0050] (1) heating the reagent;

[0051] (2) It is liquefied into water in the condensation collection pipeline and used to absorb the distilled substance (such as gaseous ammonia);

[0052] (3) The temperature of each component before heating the condensation collection pipeline.

[0053] The boiling point of the reagent of the present invention is generally higher than that of pure water. When the steam generator produces "superheated steam", the pressure in the system increases to a certain extent. The pressure above the liquid level of the digestion tube and the splash-proof bottle gradually decreases as it approaches the condenser, which is the "flash zone".

[0054] During the working process, the superheated steam lifts the reagent into the air and enters the part above the liquid level of the digestion tube and the splash-proof bottle, which is the flash evaporation area. The temperature in the "flash evaporation area" remains unchanged, but the pressure is reduced. The reagent "flashes" and the evaporation speed is accelerated. This phenomenon will continue to occur stably at a certain frequency after the system enters a certain state. We define it as "steady state".

[0055] More specifically, Figure 1 As shown, it includes: a steam generator 22, a splash-proof bottle 28 and a digestion tube 29, the digestion tube 29 is located at the bottom of the splash-proof bottle 28, the internal spaces of the splash-proof bottle 28 and the digestion tube 29 are connected, the steam output pipeline of the steam generator 22 is connected to the bottom of the digestion tube 29 through a first pipeline, a first valve 7 is connected to the first pipeline, the steam output pipeline of the steam generator 22 is connected to the top (optionally the middle or upper middle area) of the splash-proof bottle 28 through a second pipeline, and a second valve 8 is connected to the second pipeline.

[0056] In this implementation, preferably, the top of the splash-proof bottle 28 is connected to the first one-way valve 24 through a pipeline, and the first one-way valve 24 is connected to the first liquid pump 1 through a pipeline. The first liquid pump 1 is used to transport the alkaline solution (such as sodium hydroxide solution) to the digestive tract 29 through the first one-way valve 24.

[0057] In this implementation, preferably, the top of the splash-proof bottle 28 is connected to the condenser 30 through a pipeline, the condenser 30 is connected to the receiving cup through the third valve 9, the first port of the first three-way valve 15 is used to communicate with the water source, the third port of the first three-way valve 15 is connected to the second liquid pump 2, and the output port of the second liquid pump 2 is connected to the first port of the second three-way valve 16;

[0058] The second port of the second three-way valve 16 is communicated with the top of the splash-proof bottle 28 through the fourth valve 10, the third port of the second three-way valve 16 is communicated with the second port of the third three-way valve 17 through the fifth valve 11, and the third port of the third three-way valve 17 is communicated with the receiving cup;

[0059] The first port of the third three-way valve 17 is communicated with the second one-way valve 25 , and the second one-way valve 25 is communicated with the third liquid pump 3 . The input port of the third liquid pump 3 is used to receive acid (such as boric acid).

[0060] In this implementation, preferably, the condenser 30, the sixth liquid pump 6, the water tank 31, the air-cooled radiator 32 and the water-cooled radiator 33 are connected in sequence through pipelines, and the water-cooled radiator 33 is connected to the condenser 30 through a pipeline, and the air-cooled radiator 32 and the water-cooled radiator 33 work simultaneously or one of them works alone.

[0061] In this implementation, preferably, a fourth three-way valve 18 and a fifth three-way valve 19 are connected between the first valve 7 on the first pipeline and the digestive tube 29, the first port of the fourth three-way valve 18 is connected to the third one-way valve 26, and the first port of the fifth three-way valve 19 is connected to the first port of the sixth three-way valve 20 via the sixth valve 12;

[0062] The second port of the sixth three-way valve 20 is used for waste discharge, the third port of the sixth three-way valve 20 is connected to the fourth one-way valve 27, the fourth one-way valve 27 is connected to the fourth liquid pump 4, and the fourth liquid pump 4 is connected to the bottom of the receiving cup 34 through the seventh valve 13.

[0063] Optionally, the fourth three-way valve 18 and the fifth three-way valve 19 here can be replaced by a four-way valve, that is, a four-way valve is connected between the first valve on the first pipeline and the digestive tract, the first port of the four-way valve is connected to the third one-way valve, and the second port of the four-way valve is connected to the first port of the sixth three-way valve via the sixth valve.

[0064] In this implementation, preferably, the second port of the first three-way valve 15 is connected to the bottom of the steam generator 22 through the eighth valve 14 and the fifth liquid pump 5 .

[0065] In this implementation, preferably, a temperature sensor 23 is connected to the steam output pipeline or the steam generator body.

[0066] In this implementation, preferably, the junction of the steam output pipeline, the first pipeline and the second pipeline is communicated with the pressure relief valve 21 .

[0067] In this implementation, preferably, a fifth one-way valve 35 is connected to the top of the receiving cup 34 .

[0068] This implementation also provides a working method of the above-mentioned Kjeldahl nitrogen determination high-efficiency distillation system, including the following process:

[0069] The process of adding water to the digestive tube 29: the second liquid pump 2 is turned on, the fourth valve 10 is turned on, and water enters the digestive tube 29 through the second liquid pump 2 and the fourth valve 10;

[0070] Process of adding alkali to the digestion tube 29: the first liquid pump 1 is turned on, and the alkali solution enters the digestion tube 29 through the first liquid pump 1 and the first one-way valve 24;

[0071] The process of adding acid solution to the receiving cup: the third liquid pump 3 is turned on, and the acid solution (such as boric acid) enters the receiving cup 34 through the third liquid pump 3 and the second one-way valve 25;

[0072] Steam distillation process: the first valve 7 and the eighth valve 14 are opened, the fifth liquid pump 5 is turned on, water enters the steam generator 22 through the eighth valve 14 and the fifth liquid pump 5, and the water passes through the supercooled state, saturated water, gas-liquid two-phase, saturated steam, and superheated steam state in sequence, and then overflows at the bottom of the digestion tube 29 through the first valve 7, playing a heating and disturbing role; the second valve 8 is opened, and the steam at the outlet of the steam generator 22 is divided into two streams. The steam enters from the top of the splash-proof bottle 28 through the second valve 8, and the two steam streams heat the liquid in the digestion tube 29 and the splash-proof bottle 28 at the same time; during the steam distillation process, the condensation system works, and the condensate enters the receiving cup 34 through the condenser 30 and the third valve 9;

[0073] The waste discharge process of the digestion tube 29: the sixth valve 12 is opened, the first valve 7 is closed, and the second valve 8 is opened. Steam enters the splash-proof bottle 28 from the top of the splash-proof bottle 28. The liquid in the digestion tube 29 is discharged from the system through the sixth valve 12 under the pressure in the bottle. At this time, the third valve is in a closed state.

[0074] The process of adding water to the receiving cup: the second liquid pump 2 is turned on, the fifth valve 11 is turned on, and the water enters the receiving cup through the second liquid pump 2 and the fifth valve 11;

[0075] Receiving cup waste discharge process: the seventh valve 13 and the fourth liquid pump 4 are opened, and the liquid in the receiving cup 34 is discharged to the outside of the system through the seventh valve 13, the fourth liquid pump 4, the fourth one-way valve 27 and the sixth three-way valve 20 in sequence.

[0076] In the above process, except for the pump valve being in a specific state, the other pump valves are all in a closed state.

[0077] Embodiment 2:

[0078] This implementation provides a Kjeldahl nitrogen analyzer, including the Kjeldahl nitrogen determination high-efficiency distillation system described in Example 1 of the present invention.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Kjeldahl nitrogen determination high efficiency distillation system, characterized in that: include: A steam generator, a splash-proof bottle and a digestion tube, wherein the digestion tube is located at the bottom of the splash-proof bottle, the splash-proof bottle and the internal space of the digestion tube are connected, the steam output pipeline of the steam generator is connected to the bottom of the digestion tube through a first pipeline, a first valve is connected to the first pipeline, the steam output pipeline of the steam generator is connected to the splash-proof bottle through a second pipeline, and a second valve is connected to the second pipeline; After the water enters the steam generator, it passes through the supercooled state, saturated water, gas-liquid two-phase, saturated steam, and superheated steam state in sequence, and then overflows at the bottom of the digestive tube through the first valve, playing a role of heating and disturbing; The second valve is opened. At this time, the steam at the outlet of the steam generator is divided into two streams. The steam enters from the top of the splash-proof bottle through the second valve. The two streams of steam heat and disturb the liquid in the digestive tube and the splash-proof bottle at the same time. The liquid is evacuated and decompressed to flash evaporate, which accelerates the precipitation of the target product to be detected and increases the distillation rate.

2. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 1, characterized in that: The splash-proof bottle is connected to the first one-way valve through a pipeline, the first one-way valve is connected to the first liquid pump through a pipeline, and the first liquid pump is used to transport the alkali solution to the digestive tract through the first one-way valve.

3. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 1, characterized in that: The top of the splash-proof bottle is connected to the condenser through a pipeline, the condenser is connected to the receiving cup through a third valve, the first port of the first three-way valve is used to communicate with the water source, the third port of the first three-way valve is connected to the second liquid pump, and the output port of the second liquid pump is connected to the first port of the second three-way valve; The second port of the second three-way valve is connected to the top of the splash-proof bottle through the fourth valve, the third port of the second three-way valve is connected to the second port of the third three-way valve through the fifth valve, and the third port of the third three-way valve is connected to the receiving cup; The first port of the third three-way valve is communicated with the second one-way valve, the second one-way valve is communicated with the third liquid pump, and the input port of the third liquid pump is used to receive the acid solution.

4. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 3, characterized in that: The condenser, the sixth liquid pump, the water tank, the air-cooled radiator and the water-cooled radiator are connected in sequence through pipelines, and the water-cooled radiator is connected to the condenser through pipelines. The air-cooled radiator works alone or in conjunction with the water-cooled radiator.

5. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 1, characterized in that: A fourth three-way valve and a fifth three-way valve are connected between the first valve on the first pipeline and the digestive tube, the first port of the fourth three-way valve is connected to the third one-way valve, and the first port of the fifth three-way valve is connected to the first port of the sixth three-way valve via the sixth valve; The second port of the sixth three-way valve is used for waste discharge, the third port of the sixth three-way valve is connected to the fourth one-way valve, the fourth one-way valve is connected to the fourth liquid pump, and the fourth liquid pump is connected to the bottom of the receiving cup through the seventh valve; Alternatively, a four-way valve is connected between the first valve on the first pipeline and the digestive tract, the first port of the four-way valve is connected to the third one-way valve, and the second port of the four-way valve is connected to the first port of the sixth three-way valve via the sixth valve; The second port of the sixth three-way valve is used for waste discharge, the third port of the sixth three-way valve is connected to the fourth one-way valve, the fourth one-way valve is connected to the fourth liquid pump, and the fourth liquid pump is connected to the bottom of the receiving cup through the seventh valve.

6. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 3, characterized in that: The second port of the first three-way valve is connected to the bottom of the steam generator through the eighth valve and the fifth liquid pump, and a temperature sensor is connected to the steam output pipeline or the steam generator body; The junction of the steam output pipeline, the first pipeline and the second pipeline is communicated with the pressure relief valve.

7. The Kjeldahl nitrogen determination high-efficiency distillation system according to claim 1, characterized in that: The top of the receiving cup is connected with a fifth one-way valve.

8. A Kjeldahl nitrogen analyzer, characterized in that: The invention comprises the Kjeldahl nitrogen determination high-efficiency distillation system according to any one of claims 1 to 7.

9. A Kjeldahl nitrogen determination high efficiency distillation method, characterized in that: Using the Kjeldahl nitrogen determination high-efficiency distillation system according to any one of claims 1 to 7, The process includes: The process of adding water to the digestive tract: the second liquid pump is turned on, the fourth valve is turned on, and water enters the digestive tract through the second liquid pump and the fourth valve; Process of adding alkali into the digestive tube: the first liquid pump is turned on, and the alkali solution enters the digestive tube through the first liquid pump and the first one-way valve; The process of adding acid to the receiving cup: the third liquid pump is turned on, and the acid enters the receiving cup through the third liquid pump and the second one-way valve; Steam distillation process: the first valve and the eighth valve are opened, the fifth liquid pump is turned on, and water enters the steam generator through the eighth valve and the fifth liquid pump. After the water passes through the supercooled state, saturated water, gas-liquid two-phase, saturated steam, and superheated steam state in turn, it overflows at the bottom of the digestive tract through the first valve, playing a heating and disturbing role; the second valve is opened, and the steam at the outlet of the steam generator is divided into two streams. The steam enters from the top of the splash-proof bottle through the second valve. The two streams of steam heat and disturb the liquid in the digestive tract and the splash-proof bottle at the same time, thereby improving the heating efficiency, accelerating the precipitation of the target product to be detected, and increasing the distillation rate; during the steam distillation process, the condensation system works, and the condensate enters the receiving cup through the condenser and the third valve; Waste discharge process of digestive tract: the sixth valve is opened, the first valve is closed, and the second valve is opened. Steam enters the splash-proof bottle from the top of the splash-proof bottle. The liquid in the digestive tract is discharged from the system through the sixth valve under the pressure in the bottle. At this time, the third valve is closed. The process of adding water to the receiving cup: the second liquid pump is turned on, the fifth valve is turned on, and the water enters the receiving cup through the second liquid pump and the fifth valve; Receiving cup waste discharge process: the seventh valve and the fourth liquid pump are opened, and the liquid in the receiving cup is discharged out of the system through the seventh valve, the fourth liquid pump, the fourth check valve and the sixth three-way valve in sequence.

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