CN114577933A - Derivatization experiment system and method for urea hydrolysis sediment - Google Patents

Derivatization experiment system and method for urea hydrolysis sediment Download PDF

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CN114577933A
CN114577933A CN202210199608.6A CN202210199608A CN114577933A CN 114577933 A CN114577933 A CN 114577933A CN 202210199608 A CN202210199608 A CN 202210199608A CN 114577933 A CN114577933 A CN 114577933A
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reaction
derivatization
section
sample
feeding section
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向小凤
张向宇
张波
王志超
刘雯
姚伟
徐宏杰
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Xian Thermal Power Research Institute Co Ltd
Huaneng Group Technology Innovation Center Co Ltd
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Xian Thermal Power Research Institute Co Ltd
Huaneng Group Technology Innovation Center Co Ltd
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Abstract

The invention provides a derivatization experiment system and method for urea hydrolysis sediment, which improve experiment conditions, reduce detection difficulty, improve stability of sediment and improve detection precision. Comprises a reaction device, a heating device, a water removing device, a dissolving device and an analysis unit; the reaction device comprises a feeding section and a reaction section which are sequentially connected, wherein an inlet of the feeding section is connected with the water removal device, and the feeding section is used for injecting a sample to be detected; when the silane derivatization reaction is carried out, the reaction section is placed in a dissolving device, and the dissolving device is used for carrying out ultrasonic dissolution on a sample to be detected; placing part or all of the reaction sections in a heating device, wherein the reaction sections are used for carrying out silane derivatization reaction on the sample to be detected after ultrasonic dissolution; the analysis unit comprises an organic filtering membrane and a gas chromatography-mass spectrometer, the organic filtering membrane is arranged at an outlet of the reaction section and used for filtering the reactant after the reaction section is derived, and the gas chromatography-mass spectrometer is used for carrying out quantitative analysis on the filtered filtrate.

Description

Derivatization experiment system and method for urea hydrolysis sediment
Technical Field
The invention relates to the technical field of flue gas denitration of thermal power plants, in particular to a derivatization experiment system and method for urea hydrolysis sediments.
Background
In recent years, due to the defects of toxicity, harsh storage conditions, inconvenient transportation and the like of liquid ammonia, the technology for preparing ammonia by urea hydrolysis gradually replaces the liquid ammonia to prepare a denitration reducing agent, and the urea catalytic hydrolysis process becomes a research hotspot. The urea catalytic hydrolysis is a source of ammonia gas which is used as a denitration reducing agent of Selective Catalytic Reduction (SCR) by using a urea aqueous solution, and has the advantages of safety, reliability, convenient storage and transportation and the like.
Isocyanic acid substances generated in the hydrolysis process of the urea solution are difficult to decompose under the condition of heating, such as cyanuric acid, ammelide and the like, and hydrolysis reaction also occurs in the urea solution. The hydrolysis rate is greatly accelerated under the action of the catalyst, and biuret (biuret) is generated by the reaction of the biuret and urea. After the temperature is increased, the biuret is pyrolyzed into urea and isocyanic acid, the biuret and the isocyanic acid can continuously generate triurea, and the triurea can be pyrolyzed into cyanuric acid and ammonia gas, and the process is as follows:
HNCO+H2O＝NH3+CO2
N2H4CO+HNCO＝biuret
biuret+H2O＝N2H4CO+NH3+CO2
at the temperature of 150 ℃ and 190 ℃, the urea is not completely decomposed and reacts with isocyanic acid to generate biuret, and the biuret is subjected to self condensation reaction and reacts with high-concentration isocyanic acid to generate homologues. As the urea solution is hydrolyzed, the inevitable defects of incomplete decomposition, pipeline element blockage caused by deposition of generated by-products, corrosion and the like occur. Wherein, in the process of producing the urea, the biuret is generated by condensation reaction of two molecules of urea under certain temperature and pressure conditions. Meanwhile, because the urea hydrolysis reaction is the reverse reaction of urea synthesis, biuret can also be generated in the urea hydrolysis reaction process. The biuret itself can undergo condensation reaction, which results in cyanuric acid and homologues as byproducts of urea catalytic hydrolysis, the failure of timely and complete hydrolysis of isocyanic acid is an important reason for forming deposits to block pipeline elements, and the difficulty in urea decomposition at relatively low temperature is a main reason for cyanuric acid production and urea crystallization. Meanwhile, acidic substances similar to ammonium carbamate can be generated in the urea hydrolysis process, and the acidic substances are not only adhered and accumulated on the surface of a pipeline element and are difficult to remove to influence pipeline conveying, but also can corrode an oxide film made of the material on the surface of a stainless steel pipeline, so that the normal operation of a urea hydrolysis system is seriously influenced.
However, due to the complexity of the product generated at present, the components cannot be accurately detected under the GC-MS chromatographic condition, and the detection work of related analytical instruments cannot be smoothly performed due to the deposition and blockage of by-products generated by the hydrolysis of the urea solution.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a derivatization experiment system and method for urea hydrolysis sediments, which improve experiment conditions, reduce detection difficulty, improve stability of sediments and improve detection precision.
In order to achieve the purpose, the invention provides the following technical scheme:
a derivatization experiment system for urea hydrolysis sediment comprises a reaction device, a heating device, a water removal device, a dissolving device and an analysis unit;
the reaction device comprises a feeding section and a reaction section which are sequentially connected, wherein an inlet of the feeding section is connected with the water removal device, and the feeding section is used for injecting a sample to be detected;
when the silane derivatization reaction is carried out, the reaction section is placed in a dissolving device, and the dissolving device is used for carrying out ultrasonic dissolution on a sample to be detected; placing part or all of the reaction sections in a heating device, wherein the reaction sections are used for carrying out silane derivatization reaction on the sample to be detected after ultrasonic dissolution, and the heating device is used for providing heat for the silane derivatization reaction;
the analysis unit includes organic filtration membrane and gas chromatography mass spectrometer, and organic filtration membrane sets up the export of reaction section, organic filtration membrane is used for filtering the reactant after the reaction section is derived, gas chromatography mass spectrometer is used for carrying out quantitative analysis to the filtrating back filtrating.
Preferably, the feeding section adopts a three-section structure and comprises a first feeding section, a second feeding section and a third feeding section which are sequentially and rotatably connected, the first feeding section, the second feeding section and the third feeding section are all provided with holes for injecting a sample to be detected, the bottom of the third feeding section is connected with an inlet of the reaction section, and a drying agent is filled in the third feeding section.
Preferably, a plurality of small holes which are uniformly distributed are formed in the bottom end face of the third feeding section.
Preferably, the water removal device adopts any one of a rotary evaporator, a nitrogen purging device and a freeze dryer.
Preferably, the nitrogen purging device comprises a gas needle, a nitrogen flowmeter, a nitrogen valve and a nitrogen bottle which are connected in sequence, wherein the nitrogen bottle is used for providing nitrogen, the nitrogen valve and the nitrogen flowmeter (6) are used for controlling the flow of nitrogen, and the gas needle extends into the feeding section to the position above the surface of the sample to be detected in the reaction section.
Preferably, the heating device adopts a constant-temperature glycerine bath pan.
Preferably, the dissolving device adopts an ultrasonic dissolving instrument.
Preferably, the analysis unit further comprises a thermogravimetric analyzer for acquiring a TG curve of the sample to be detected.
A derivatization experimental method for urea hydrolysis sediment comprises the following steps:
carrying out water removal pretreatment on a sample to be detected;
injecting the dewatered sample to be detected into a reaction section through a feeding section, adding a silanization reagent, placing the reaction section into a dissolving device for ultrasonic dissolving, and placing the reaction section into a heating device for silane derivatization reaction;
and after the silane derivatization reaction is finished, filtering and extracting the reaction product after the derivatization of the reaction section through an organic filter membrane, sending the extracting solution into a gas chromatography-mass spectrometer, generating a peak in a monitoring ion mode of the gas chromatography-mass spectrometer, and detecting and obtaining the components of the sample to be detected.
Preferably, before the addition of the silylation reagent, pyridine and acetonitrile are added into the sample to be detected after the water is removed. Compared with the prior art, the invention has the following beneficial effects:
the invention provides a derivatization experimental system for urea hydrolysis sediment, which adopts a derivatization method mature and applied to the food industry to perform derivatization treatment on the sediment in the urea hydrolysis process, uses silane groups in a derivatization reagent to replace active hydrogen on hydroxyl and amino in cyanuric acid homologues, reduces the polarity of the hydrogen, increases the stability and volatility of the cyanuric acid homologues in the sediment, improves the chromatographic condition, reduces the temperature requirement on heating and vaporization of a gas chromatograph, is suitable for detection and analysis by adopting analyzers such as a gas chromatograph-mass spectrometer and the like, and detects specific components of the cyanuric acid homologues in the sediment. In addition, the water trap that increases can effectively restrain the hydrolysis of urea solution on the basis of not destroying the sample internal material that awaits measuring, reduces the deposit of urea hydrolysis accessory substance and blocks up, and heating device can reduce sample moisture when providing required heat for derivatization, and organic filter membrane can further filter the reactant simultaneously and get rid of impurity, reduces the detection degree of difficulty of analytical instrument such as follow-up gas chromatography mass spectrometry combination appearance, promotes and detects the precision, promotes thermal stability.
Drawings
FIG. 1 is a schematic diagram of a derivatization experimental system according to an embodiment of the present invention;
FIG. 2 is a schematic view of ultrasonic dissolution of a sample to be tested in a reaction zone according to the present invention;
FIG. 3 is a schematic diagram of the experimental principle of derivatization in the present invention.
In the figure, a feed section 1, a reaction section 2, a heating device 3, a dissolving device 4, a gas needle 5, a nitrogen gas flowmeter 6, a nitrogen gas valve 7 and a nitrogen gas bottle 8.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention is described in further detail below with reference to the accompanying drawings:
as shown in fig. 1 and 2, the derivatization experimental system for urea hydrolysis sediment comprises a reaction device, a heating device 3, a water removal device, a dissolving device 4 and an analysis unit;
the reaction device comprises a feeding section 1 and a reaction section 2 which are sequentially connected, wherein an inlet of the feeding section 1 is connected with a water removal device, and the feeding section 1 is used for injecting a sample to be detected;
during the derivatization reaction of silane, the reaction section 2 is placed in a dissolving device 4, and the dissolving device 4 is used for carrying out ultrasonic dissolution on a sample to be detected; a part of or all of the reaction sections 2 are arranged in a heating device 3, the reaction sections 2 are used for carrying out silane derivatization reaction on the sample to be detected after ultrasonic dissolution, and the heating device 3 is used for providing heat for the silane derivatization reaction;
the analytical element includes organic filtration membrane and gas chromatography-mass spectrometer, and organic filtration membrane sets up the export of reaction section 2, organic filtration membrane is used for filtering the reactant after 2 derivatives of reaction section, gas chromatography-mass spectrometer is used for carrying out quantitative analysis to the filtrating after filtering.
The invention provides a derivatization experimental system for urea hydrolysis sediment, which adopts a derivatization method mature and applied to the food industry to perform derivatization treatment on the sediment in the urea hydrolysis process, uses silane groups in a derivatization reagent to replace active hydrogen on hydroxyl and amino in cyanuric acid homologues, reduces the polarity of the hydrogen, increases the stability and volatility of the cyanuric acid homologues in the sediment, improves the chromatographic condition, reduces the temperature requirement on heating and vaporization of a gas chromatograph, is suitable for detection and analysis by adopting analyzers such as a gas chromatograph-mass spectrometer and the like, and detects specific components of the cyanuric acid homologues in the sediment. In addition, the water trap that increases can effectively restrain the hydrolysis of urea solution on the basis of not destroying the sample internal material that awaits measuring, reduces the deposit of urea hydrolysis accessory substance and blocks up, heating device 3 can reduce sample moisture when providing required heat for derivatization reaction, organic filtration membrane can further filter the reactant simultaneously and get rid of impurity, reduces the detection degree of difficulty of analytical instrument such as follow-up gas chromatography mass spectrometry combination appearance, promotes the detection precision, promotes thermal stability.
Further, the feeding section 1 adopts a three-section structure and comprises a first feeding section, a second feeding section and a third feeding section which are sequentially and rotatably connected, open holes for injecting a sample to be detected are formed in the first feeding section, the second feeding section and the third feeding section, the bottom of the third feeding section is connected with an inlet of the reaction section 2, and a drying agent is filled in the third feeding section.
The three sections of the feeding section 1 can be opened and closed in a rotating mode, when the feeding section 1 is in a sealed and closed state, only one section of the feeding section 1 is required to be rotated, so that the three sections of openings are not aligned and communicated, the inlet path of the reaction tube can be closed, when gas and a reagent are required to be introduced for reaction, the inlet path can be opened only by rotating the three sections of openings uniformly and completely communicated, the storage and sealing of the silane reagent in the reaction tube are met, and the sample after derivative treatment is sealed, so that the operation is simple and convenient, and the practicability is high.
The third feeding section is a drying agent filling section, and a plurality of small holes which are uniformly distributed are formed in the bottom end face of the third feeding section so as to facilitate moisture adsorption.
Preferably, the desiccant is one of physically adsorbed desiccants such as silica gel, alumina gel, molecular sieve, activated carbon, bone charcoal and mineral desiccant, and is used for adsorbing moisture of introduced gas, keeping reaction dryness on the basis of not influencing chemical reaction and inhibiting hydrolysis. In this embodiment, the third feeding section is filled with physically adsorbed silica gel desiccant.
Preferably, the reaction device adopts a cylindrical pointed bottom glass tube with the diameter of 10-20 mm.
Preferably, the water removal device adopts any one of a rotary evaporator, a nitrogen purging device and a freeze dryer.
Wherein, nitrogen gas purging device is including the gas needle 55, nitrogen gas flowmeter 6, nitrogen gas valve 7 and the nitrogen gas bottle 8 that connect gradually, wherein, nitrogen gas bottle 8 is used for providing nitrogen gas, nitrogen gas valve 7 and nitrogen gas flowmeter 6 are used for controlling nitrogen gas flow, gas needle 55 stretches into feeding section 1 extremely the sample surface top of waiting to detect in the reaction section 2, and nitrogen gas needle 55 stretches into length and position are steerable, and suggestion control nitrogen gas pressure is about 0.02MPa, and nitrogen gas flow is about 15L/min, and gas needle 55 length is about 150 mm.
After the urea hydrolysis sediment sample is extracted by using the mixed solvent, nitrogen purging and water removing treatment are required to be carried out, so that the interference of hydroxyl derivatization is avoided. Nitrogen purging to remove water, placing the supernatant in a pointed-bottom glass silanization reaction tube, continuously blowing nitrogen at 70 ℃, combining the temperature of the oil bath pot heating device 3, blowing the nitrogen to the surface of the heated solution by using the gas needle 55, and quickly and effectively evaporating and concentrating the sample.
Preferably, the heating device 3 adopts a constant temperature glycerine bath pan.
Wherein, the glycerine bath pot provides heat for silane derivatization, effectively avoids the interference of moisture, and the temperature is constant at a set value, so that the reaction is stably carried out. And (3) finishing the silane derivatization reaction under the heat provided by the glycerin bath, closing the sealed reaction device, standing at normal temperature for about 15min, and then performing the next treatment.
Preferably, the dissolving device 4 adopts an ultrasonic dissolving instrument.
Wherein, after the sample after dehydration is added with the silanization reagent, ultrasonic accelerated dissolution is needed to ensure that the hydroxyl reaction of the sediment is fully derived.
Preferably, the silylation agent can be selected from TMS-Silylating agents such as SIGMA, or a formulated silylation agent, so as to achieve the purpose of catalyzing and accelerating the reaction. The silylating agent is typically stored under nitrogen to avoid moisture absorption failure.
Further, the analysis unit further comprises a thermogravimetric analyzer, and the thermogravimetric analyzer is used for acquiring the TG curve of the sample to be detected.
The derivatization experiment system for urea hydrolysis sediments in one embodiment of the invention has the following working principle:
and performing derivatization treatment on the sediment, and detecting specific components of the cyanuric acid homologues in the sediment. The device was connected and checked for air tightness. The reaction section 2 is placed in a constant temperature glycerol bath kettle, nitrogen is sent to the bottom of the reaction tube from a nitrogen bottle 8 through a nitrogen valve 7 and a nitrogen flow meter 6 by a gas needle 55, and a sample is blown. The silane derivatization reaction tube is placed in an ultrasonic dissolving device 4, so that the sample substance in the reaction tube is dissolved by ultrasonic. Extracting a sediment sample by using a solvent, carrying out nitrogen purging and concentration on an extracting solution, deriving hydroxyl of the sediment by using a silanization reagent, enabling the sediment to generate a peak under a GC-MS monitoring ion mode, and finally obtaining a main component of the sediment.
Examples
Referring to fig. 3, the following describes the specific implementation steps of the system according to the present invention in further detail with reference to the following embodiments:
the preparation of the experimental reagent comprises screening of a mixed solvent, preparation of cyanuric acid and an isogenous standard solution thereof, and preparation of a sediment solution.
Step 1: and determining the mixed reagent of the sample. If the mixed solvent of the sample is diethylamine-acetonitrile aqueous solution, the deposit in the hydrolysis process of urea can be completely dissolved, and the cyanuric acid and the homologue thereof are prevented from complex reaction.
Further, the screening of the mixed solvent is to prevent cyanuric acid and homologues thereof in the deposited blockage from generating complex reaction in the urea hydrolysis or catalytic hydrolysis process, and the screening of the mixed solvent capable of completely dissolving the blockage, such as diethylamine-acetonitrile aqueous solution, pyridine-acetonitrile aqueous solution and the like. The smooth work of the gas chromatograph is ensured, and the problem that the thermogravimetric analyzer cannot analyze the components of the blockage is also solved.
Step 2: and (5) preparing a standard solution. Preparing standard solutions of cyanuric acid and homologues thereof, respectively weighing 10.0mg of homologue standard, respectively ultrasonically dissolving with the screened mixed reagent, respectively transferring to 100ml volumetric flask labels for recording, refrigerating for storage, and taking supernatant after standing and layering when in use.
And step 3: and (4) preparing a sediment solution. Weighing a certain mass of the sediment plug, grinding into powder, sieving to select 40-mesh particles, and placing in a 50ml centrifuge tube with a plug. Adding 20ml of mixed reagent, swirling for 1min to dissolve to form uniform mixed solution, and performing ultrasonic extraction for 30 min. Centrifuging at 4000r/min for 5min, standing to separate the solution, and collecting supernatant 200 μ L.
And 4, step 4: and (3) carrying out silanization dehydration pretreatment, wherein in order to prevent the silanization reagent from reacting with hydroxyl to influence the test process, the sample is subjected to dehydration pretreatment before silanization. The water removal pretreatment comprises various modes such as water removal by a rotary evaporator, nitrogen purging and water removal, freeze drying and water removal, and the mode without damaging substances in the sample is selected for water removal. In this embodiment, nitrogen purging is selected to remove water without damaging the inside of the deposit. And (3) placing the supernatant obtained in the step (3) into a pointed-bottom glass silanization reaction tube with the volume of about 10ml, and drying the tube at 70 ℃ by nitrogen.
Further, the choice of silylating agent, such as the silylating agent BSTFA, and silylation derivatives from REGIS, or the silylating agent formed by adding TMCS to the silylating agent BSTFA (BSTFA + TMCS), can catalyze the reaction. The silylating agent is typically stored under nitrogen to avoid moisture absorption failure.
And 5: and (3) performing silane derivatization reaction. Placing the reaction bottle in a constant-temperature glycerine bath kettle at 70 ℃, respectively adding 150 mu L of pyridine and 150 mu L of acetonitrile after drying the clear liquid in the test tube, and preventing cyanuric acid and homologues thereof in the solution from reacting with each other to form a stable complex; depending on the amount of sample, addition of excess silylation reagent, such as 300. mu.L, to the silylation reaction tube reduces adsorption on the surface of the vessel and the small amount of water that may be present. Ultrasonic dissolving for 1min, heating in 70 deg.C water bath for 45min for derivatization, filtering the solution with organic filter membrane, and detecting with GC-MS and thermogravimetric analyzer.
Step 6: detecting by a gas chromatograph, selecting a chromatographic column HP-5MS capillary column of 30m multiplied by 0.25mm multiplied by 0.25m, considering that the polarity of cyanuric acid and homologues thereof after derivatization treatment is weakened, and shortening the peak-producing time of the target object. Setting the temperature of a sample inlet to be about 260 ℃ and 285 ℃ to ensure that the sample is completely vaporized; the sample introduction is not divided, the solution is delayed for 5-6min, the sample introduction amount is about 1 mu L, the carrier gas is high-purity helium, the flow rate of the carrier gas is about 1.5-1.6mL/min, the initial temperature of the programmed temperature rise is set to be 75 ℃ and kept for 1min, the temperature rise rate in the temperature range of 75-250 ℃ is 15 ℃/min, and the temperature rise rate after the temperature of 300 ℃ is 25 ℃/min and kept for 5 min.
Further, the conditions of the gas chromatograph and the selection of the chromatographic column and the capillary column need to consider the reduction of the polarity of cyanuric acid and homologs thereof after derivatization, and the time for peak discharge of the target substance needs to be shortened. The temperature of the sample inlet is selected to ensure the total vaporization temperature of the sample.
And 7: and (6) data processing. Extracting urea hydrolysis sediment sample with solvent, purging the extract with nitrogen gas for concentration, deriving hydroxyl of sediment with silanization reagent, allowing peak to appear under GC-MS monitoring ion mode, and quantifying with external standard method to obtain main components of sediment.
Further, derivatization is carried out on hydroxyl silane on the sediment, peaks appear on hydroxyl groups derived by utilizing a derivatization silylation reagent, and the total ion current chromatogram of derivatives of isocyanic acid and homologues thereof in the sediment and the mass spectrogram of derived products are obtained by integrating the results of GC-MS and thermogravimetric analyzer tests of a gas chromatograph test. Thereby obtaining the mass fraction of the main component of the deposit and its decomposition temperature range.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. A derivatization experiment system for urea hydrolysis sediment is characterized by comprising a reaction device, a heating device (3), a water removal device, a dissolving device (4) and an analysis unit;
the reaction device comprises a feeding section (1) and a reaction section (2) which are sequentially connected, an inlet of the feeding section (1) is connected with a water removal device, and the feeding section (1) is used for injecting a sample to be detected;
when the silane derivatization reaction is carried out, the reaction section (2) is placed in a dissolving device (4), and the dissolving device (4) is used for carrying out ultrasonic dissolution on a sample to be detected; a part of or all of the reaction sections (2) are arranged in a heating device (3), the reaction sections (2) are used for carrying out silane derivatization reaction on the sample to be detected after ultrasonic dissolution, and the heating device (3) is used for providing heat for the silane derivatization reaction;
the analysis unit includes organic filtration membrane and gas chromatography mass spectrometer, and organic filtration membrane sets up the export of reaction section (2), organic filtration membrane is used for filtering the reactant after reaction section (2) derivatization, gas chromatography mass spectrometer is used for carrying out quantitative analysis to the filtrating after filtering.
2. The derivatization experimental system for urea hydrolysis sediment according to claim 1, wherein the feeding section (1) has a three-section structure, and comprises a first feeding section, a second feeding section and a third feeding section which are sequentially and rotatably connected, the first feeding section, the second feeding section and the third feeding section are respectively provided with an opening for injecting a sample to be detected, the bottom of the third feeding section is connected with the inlet of the reaction section (2), and the third feeding section is filled with a drying agent.
3. The derivatization experimental system for urea hydrolysis sediment as claimed in claim 2, wherein the bottom end face of the third feeding section is provided with a plurality of small holes which are uniformly distributed.
4. The derivatization experimental system for urea hydrolysis sediment according to claim 1, wherein the water removal device is any one of a rotary evaporator, a nitrogen purging device and a freeze dryer.
5. The derivatization experimental system for urea hydrolysis sediment according to claim 4, wherein the nitrogen purging device comprises a gas needle (5), a nitrogen flow meter (6), a nitrogen valve (7) and a nitrogen bottle (8) which are connected in sequence, wherein the nitrogen bottle (8) is used for supplying nitrogen, the nitrogen valve (7) and the nitrogen flow meter (6) are used for controlling the nitrogen flow, and the gas needle (5) extends into the feeding section (1) to a position above the surface of the sample to be detected in the reaction section (2).
6. The derivatization experimental system for urea hydrolysis sediment as claimed in claim 1, wherein the heating device (3) adopts a constant-temperature glycerine bath.
7. The derivatization experimental system for urea hydrolysis deposits, according to claim 1, wherein the dissolving device (4) employs an ultrasonic dissolver.
8. The derivatization experimental system for urea hydrolysis deposits according to claim 1, wherein the analysis unit further comprises a thermogravimetric analyzer, and the thermogravimetric analyzer is used for acquiring a TG curve of a sample to be detected.
9. An experimental method for derivatization of urea hydrolysis deposits, based on the experimental system of any one of claims 1 to 8, comprising the following steps:
carrying out water removal pretreatment on a sample to be detected;
injecting the dewatered sample to be detected into a reaction section (2) through a feeding section (1), adding a silanization reagent, placing the reaction section (2) into a dissolving device (4) for ultrasonic dissolving, and then placing the reaction section (2) into a heating device (3) for silane derivatization reaction;
and (3) after the silane derivatization reaction is finished, filtering and extracting the reactant after the derivatization of the reaction section (2) through an organic filter membrane, sending the extracting solution into a gas chromatography-mass spectrometer, performing peak generation under a monitoring ion mode of the gas chromatography-mass spectrometer, and detecting and obtaining the components of the sample to be detected.
10. The method for performing derivatization experiments on urea hydrolysis deposits according to claim 9, wherein pyridine and acetonitrile are added to the sample to be tested after water removal before the silylation reagent is added.
CN202210199608.6A 2022-03-01 2022-03-01 Derivatization experiment system and method for urea hydrolysis sediment Pending CN114577933A (en)

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