Process for decolorization of ethylene amine reactants
Patent Information
- Application Number
- CN202510363808.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-09-29
AI Technical Summary
[0005]在传统的乙烯胺生产工艺中，从胺化反应器出来的乙烯胺产品未经脱色处理就进行后续的液氨闪蒸回收和乙烯胺产品的精馏，由于乙烯胺产品多属于热敏性、易氧化物质，不适宜长时间加热，而现有的分离工艺多为多塔串联负压精馏工艺，物料在精馏过程中停留时间长，有轻微分解，加之微量空气漏入造成物料高温变质
[0023]本发明的乙烯胺反应物的脱色工艺通过对乙烯胺反应物进行脱色处理，脱除部分不饱和键和部分官能团，从而提高反应产物的热稳定性和抗氧化性，使得反应产物在后续精馏过程中更稳定，降低乙烯胺反应物的颜色在后续分离过程中对于热敏因素的敏感性，并改善产品的颜色，因此，可节约投资并改进产品品质。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of ethyleneamine production technology, specifically to a decolorization process for ethyleneamine reactants. Background Technology
[0002] Ethyleneamine, also known as ethylenediamine, includes ethylenediamine (EDA) and its homologous polyethylene polyamine series products. It is an important organic chemical raw material with a wide range of applications.
[0003] Traditional ethyleneamine industrial production facilities produce 5 to 10 different products, including ethylenediamine (EDA), piperazine (PIP), diethylenetriamine (DETA), aminoethylpiperazine (AEP), hydroxyethylpiperazine (HEP), hydroxyethylethylenediamine (AEEA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), mixed amines (SMA20, SMA30), and heavy amines. Due to the need for separation and purification of these multiple products, the production process is often quite lengthy.
[0004] The traditional process for producing ethyleneamine using the monoethanolamine (MEA) method is as follows: Figure 1 As shown, in the presence and action of hydrogen and an amination catalyst, raw materials including liquid ammonia (NH3), monoethanolamine (MEA), ethylenediamine (EDA), aminoethylethylenediamine (AEEA), diethylenetriamine (DETA), diethanolamine (DEA), hydroxyethylpiperazine (HEP), and ethylene oxide (EO) are injected into the reactor in stages. Amination reactions occur under pressure and temperature to produce a series of ethyleneamine products. These reactions are a series of chain reactions, and the reaction products include a series of linear and cyclic ethyleneamine products.
[0005] In traditional ethyleneamine production processes, the ethyleneamine product from the amination reactor undergoes subsequent liquid ammonia flash evaporation recovery and ethyleneamine product distillation without decolorization. Since ethyleneamine is largely a heat-sensitive and easily oxidized substance, it is unsuitable for prolonged heating. Existing separation processes are mostly multi-tower series negative pressure distillation processes, resulting in long residence times for the material during distillation, slight decomposition, and the introduction of trace amounts of air causing high-temperature deterioration. Furthermore, the purified product after distillation exhibits a certain decrease in purity and the generation of trace unknown impurities, often turning yellow and darkening in color. This color deterioration trend intensifies during storage. The traditional ethanolamine method for preparing ethyleneamine via hydroammoniation operates at approximately 200°C. Under these conditions, the reaction products contain a small amount of C=C unsaturated bonds and trace amounts of aldehyde groups (-CHO) and carbonyl groups (-C=O). During subsequent distillation separation, these groups are unstable under heat and oxygen, easily leading to poor product color and poor storage stability. Therefore, there is a need in this field to design a decolorization process for ethyleneamine reactants. Summary of the Invention
[0006] To address the aforementioned problems in the prior art, this invention improves the thermal stability and antioxidant properties of the ethyleneamine reaction product by decolorizing it, thereby making the ethyleneamine reaction product more stable in subsequent distillation processes and improving the product's color.
[0007] One objective of this invention is to provide a decolorization process for ethyleneamine reactants, the process comprising:
[0008] In the presence of hydrogen and a catalyst, the ethyleneamine reactants undergo a decolorization reaction in a decolorization reactor. The catalyst includes a binary metal catalyst, wherein the main metal in the binary metal catalyst is Ni, and the auxiliary metal is selected from one or more of Ru, Re, Pt, and Pd.
[0009] The temperature for the decolorization reaction is 100–240°C;
[0010] The operating pressure of the decolorization reactor is 10–30 MPa.
[0011] In some embodiments of the present invention, the decolorization temperature range is 135–180°C.
[0012] In some embodiments of the present invention, the operating pressure of the decolorization reactor is 15-24 MPa.
[0013] In some embodiments of the present invention, the catalyst is a supported catalyst, and the support includes Al2O3 and / or SiO2.
[0014] In some embodiments of the present invention, the content of the main metal Ni ranges from 5 to 20 wt%, and the content of the auxiliary metal ranges from 0 to 2 wt%.
[0015] In some embodiments of the present invention, the ethyleneamine reactant comprises 20-70 wt% of a mixed ethyleneamine.
[0016] In some embodiments of the present invention, the ethyleneamine mixed amines include EDA, PIP, MEA, DETA, AEEA, AEP, HEP, and SMA.
[0017] In some embodiments of the present invention, the single-pass conversion rate, in terms of MEA, is less than 2% in the decolorization reaction.
[0018] In some embodiments of the present invention, the volume hourly space velocity (GHSV) of hydrogen is 100–500 h⁻¹. -1 The liquid hourly space velocity (WHSV) of the ethyleneamine reactant is 0.5–10 h⁻¹. -1 .
[0019] In some embodiments of the present invention, the temperature difference of the decolorization reactor is controlled between 0 and 1°C.
[0020] In some embodiments of the present invention, the decolorization reactor is a fixed-bed reactor.
[0021] Another object of the present invention is to provide a process for producing ethyleneamine, which includes the decolorization process of the present invention. In the ethyleneamine production process, the decolorization treatment described in the present invention is performed on the ethyleneamine reactants before flash evaporation and fractionation to improve the thermal stability and oxidation resistance of the ethyleneamine reactants in subsequent separation processes.
[0022] The present invention has the following beneficial technical effects compared with the prior art:
[0023] The decolorization process of the ethyleneamine reactants of the present invention removes some unsaturated bonds and some functional groups by decolorizing the ethyleneamine reactants, thereby improving the thermal stability and antioxidant properties of the reaction products. This makes the reaction products more stable in subsequent distillation processes, reduces the sensitivity of the color of the ethyleneamine reactants to heat-sensitive factors in subsequent separation processes, and improves the color of the products. Therefore, it can save investment and improve product quality.
[0024] On the other hand, the decolorization process of the present invention can maintain the selective distribution of ethyleneamine reaction products during the decolorization process and minimize further amination reactions during the decolorization process. In an exemplary embodiment of the present invention, the single-pass conversion rate of monoethanolamine (MEA) during the decolorization process is controlled to be below 2%. Therefore, the present invention effectively decolorizes the ethyleneamine reactants while minimizing the adverse effects of the decolorization process on the selective distribution of ethyleneamine products. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the traditional ethyleneamine production process.
[0026] Figure 2 This is a schematic diagram of the ethyleneamine production process, including the ethyleneamine reactant decolorization process of embodiments of the present invention.
[0027] Figure 3 for Figure 2 A schematic diagram of the ethyleneamine reactant decolorization process according to an embodiment of the present invention. Detailed Implementation
[0028] The present invention will be described in detail below with reference to specific embodiments and exemplary models. These specific descriptions and exemplary models are only for illustrating the present invention and do not constitute a limitation on the scope and substance of the present invention.
[0029] This invention relates to a decolorization treatment of ethyleneamine reactants before separation, specifically decolorizing the ethyleneamine reactants exiting the ethyleneamine synthesis reactor. In a specific embodiment of this invention, the decolorization is performed on ethyleneamine reactants synthesized via the hydrogen amination reaction using the ethanolamine method. The ethyleneamine reactant material to be decolorized contains not only the mixed ethyleneamines generated during the amination reaction but also unreacted raw materials (e.g., liquid ammonia). The ethyleneamine reactants to be decolorized according to this invention may include: 20–70 wt% mixed ethyleneamines, 20–80 wt% NH3, and 0–15 wt% H2. In an exemplary embodiment of this invention, the mixed ethyleneamines include EDA, PIP, MEA, DETA, AEEA, AEP, HEP, and SMA.
[0030] The decolorization process of this invention is carried out in the presence of hydrogen and a catalyst. The decolorization reactor can be a fixed-bed reactor, in which the catalyst for the decolorization reaction is packed. Other reactors suitable for hydrogenation catalytic reactions in the art can also be used as the decolorization reactor.
[0031] The catalyst used in the decolorization reaction of this invention is a binary metal catalyst, wherein the main metal is Ni as the active component, and the auxiliary metal can be selected from one or more metals selected from Ru, Re, Pt, and Pd. Furthermore, the catalyst can be a supported catalyst, wherein the support material can be a commonly used supported catalyst support material in the art, such as Al2O3 and / or SiO2. In specific embodiments of this invention, a supported binary metal catalyst is used, such as Ni-Ru / Al2O3, Ni-Re / Al2O3, or Ni-Pt / Al2O3. In the supported binary metal catalyst, the content of the main metal Ni can range from 5 to 20 wt%, and the content of the auxiliary metal can range from 0 to 2 wt%, for example, the content of Ru, Re, and Pt can range from 0 to 2 wt%. The support is Al2O3. In an exemplary embodiment of the present invention, the supported bimetallic catalyst used includes: 10wt% Ni-1.0wt% Ru / Al2O3, 15wt% Ni-1.0wt% Ru / Al2O3, 15wt% Ni-0.75wt% Re / Al2O3, and 15wt% Ni-0.75wt% Pt / Al2O3.
[0032] Furthermore, the catalyst used in the decolorization reaction of the present invention can also be a metal catalyst known in the art for the preparation of ethyleneamine by the hydroammoniation reaction of ethanolamine.
[0033] This invention, used in decolorization reactions, allows for the control of process parameters such as temperature and operating pressure during the decolorization reaction. This ensures that the ethyleneamine reactants achieve decolorization without affecting the selective distribution of the ethyleneamine product, thus preventing further amination reactions during the decolorization process and ensuring the selective distribution of the target product achieved through the original amination reaction is not compromised. This invention can determine whether an undesirable amination reaction has occurred during the decolorization process by measuring the single-pass conversion rate of MEA in the ethyleneamine reactants. In embodiments of this invention, the single-pass conversion rate of MEA during the decolorization process of the ethyleneamine reactants is controlled to be below 2%. In an exemplary embodiment of this invention, the single-pass conversion rate of MEA during the decolorization process of the ethyleneamine reactants is below 0.5%.
[0034] The decolorization reaction temperature of the present invention can be 100-240°C. In a specific embodiment of the present invention, the decolorization reaction temperature is 135-180°C.
[0035] In order to further suppress the occurrence of amination reaction during the decolorization process, the present invention can control the temperature difference in the decolorization reactor, for example, control the temperature difference in the decolorization reactor to 0-1℃.
[0036] The operating pressure of the decolorization reactor of the present invention can be 10-30 MPa. In a specific embodiment of the present invention, the decolorization operating pressure is 15-24 MPa.
[0037] In the decolorization reaction of this invention, the volume hourly space velocity (GHSV) of hydrogen can be 100–300 h⁻¹. -1 In a specific embodiment of the present invention, the hydrogen volume hourly space velocity is 100–200 h⁻¹. -1 The liquid hourly space velocity (WHSV) of the ethyleneamine reactants is 1–10 h⁻¹. -1 In a specific embodiment of the present invention, the liquid hourly space velocity (LHSV) of the ethyleneamine reactant is 0.5–1.8 h⁻¹. -1 .
[0038] In an exemplary embodiment of the present invention, as follows: Figure 3 The decolorization process shown is illustrated in the schematic diagram of the ethyleneamine production process. Figure 2 As shown. Combined with Figure 2 and Figure 3 It is known that ethyleneamine is synthesized by amination reaction in an amination reactor (first-stage reactor) using monoethanolamine and liquid ammonia as raw materials under hydrogen conditions. Special ethyleneamine products are synthesized from special monomers in a functional reactor. These products and unreacted raw materials constitute ethyleneamine reactants. After passing through a heat exchanger (interstage cooler), the ethyleneamine enters a decolorization reactor for decolorization treatment. The ethyleneamine reactants after decolorization treatment enter the downstream for flash evaporation and distillation.
[0039] In an exemplary embodiment of the present invention, a binary metal catalyst is used to decolorize the ethyleneamine reactants. A certain amount of catalyst is pre-packed in a tubular adiabatic fixed-bed decolorization reactor (35L, 200mm diameter, 2.5m height), with 6mm thick magnetic spheres of 300mm thickness fixing the catalyst both above and below the catalyst bed. The material from the amination reactor and hydrogen are mixed and then enter a heat exchanger to adjust the temperature to the decolorization treatment temperature and the pressure to the decolorization operating pressure. This mixed stream continuously enters the decolorization reactor from the bottom for decolorization.
[0040] In the following examples, ethyleneamine reactants were decolorized under hydrogen and catalyst conditions by adjusting the space velocity of the ethyleneamine reactants and the hydrogen space velocity, the hydrogenation temperature, and the reactor operating pressure. The color change of the ethyleneamine reactants before and after decolorization was measured using the Hazen colorimetric method to evaluate the decolorization effect.
[0041] Example 1
[0042] The decolorization process in this embodiment was tested using catalyst #1, a binary metal catalyst with an effective composition of 10wt% Ni-1.0wt% Ru / Al2O3. The specific surface area of Al2O3 is 50-150 m². 2 / g.
[0043] In this embodiment, the material undergoing decolorization treatment is ethyleneamine reactant 1, the specific composition of which is:
[0044] EDA 12.7wt%, PIP 1.6wt%, MEA 23.7wt%, DETA 3.7wt%, AEEA 3.2wt%, AEP 0.2wt%, HEP 0.1wt%, SMA 1.7wt%, H2O 6.6wt%, NH3 46.5wt%.
[0045] 6 kg of catalyst #1 was loaded into the decolorization reactor. Hydrogen gas and ethyleneamine reactant 1 were introduced and mixed online. The operating pressure was 24 MPa, the inlet temperature was 135℃, and the temperature difference inside the decolorization reactor was controlled between 0 and 1℃. The mixed stream entered the decolorization reactor, and the hydrogen volume hourly space velocity was controlled at 150 h⁻¹. -1 The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 1.8 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color of the ethyleneamine reactants decreased by 50 Hz before and after the decolorization treatment in this embodiment. During the decolorization treatment, the single-pass conversion rate of MEA was less than 0.5%.
[0046] Example 2
[0047] The decolorization process in this embodiment was tested using catalyst #2, a binary metal catalyst with an effective composition of 15wt% Ni-1.0wt% Ru / Al2O3. The specific surface area of Al2O3 is 50-150 m². 2 / g.
[0048] In this embodiment, the material undergoing decolorization treatment is ethyleneamine reactant 2, the specific composition of which is:
[0049] 12.3wt%EDA, 1.5wt%PIP, 22.5wt%MEA, 3.5wt%DETA, 3.0wt%AEEA, 0.3wt%AEP, 0.1wt%HEP, 1.6wt%SMA, 6.2wt%H2O, 49.0wt%NH3.
[0050] 10 kg of catalyst #2 was loaded into the decolorization reactor. Hydrogen gas and ethyleneamine reactant 2 were introduced and mixed online. The operating pressure was 20 MPa, the inlet temperature was 160 °C, and the temperature difference inside the decolorization reactor was controlled between 0 and 1 °C. The mixed stream entered the decolorization reactor, and the hydrogen volume hourly space velocity was controlled at 200 h⁻¹. -1 The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 0.8 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color of the ethyleneamine reactants decreased by 15 Hz before and after the decolorization treatment in this embodiment. During the decolorization treatment, the single-pass conversion rate of MEA was less than 0.5%.
[0051] Example 3
[0052] The decolorization process in this embodiment was tested using catalyst #2, a binary metal catalyst with an effective composition of 15wt% Ni-1.0wt% Ru / Al2O3. The specific surface area of Al2O3 is 50-150 m². 2 / g.
[0053] In this embodiment, the material undergoing decolorization treatment is ethyleneamine reactant 3, whose specific components are: 12.5 wt% EDA, 1.4 wt% PIP, 21.1 wt% MEA, 3.3 wt% DETA, 3.2 wt% AEEA, 0.3 wt% AEP, 0.2 wt% HEP, 1.5 wt% SMA, 5.8 wt% H2O, and 50.7 wt% NH3.
[0054] 15 kg of catalyst #2 was loaded into the decolorization reactor. Hydrogen and ethyleneamine reactant 3 were introduced and mixed online. The operating pressure was 15 MPa, the inlet temperature was 180 °C, and the temperature difference inside the decolorization reactor was controlled at 0–1 °C. The mixed stream entered the reactor, and the hydrogen volume hourly space velocity was controlled at 100 h⁻¹. -1The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 0.5 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color of the ethyleneamine reactants decreased by 2 Hz before and after the decolorization treatment in this embodiment. During the decolorization treatment, the single-pass conversion rate of MEA was less than 0.5%.
[0055] Example 4
[0056] The decolorization process in this embodiment was tested using catalyst #3, a binary metal catalyst with an effective component of 15wt% Ni-0.75wt% Re / Al2O3. The specific surface area of Al2O3 is 50–150 m² / g. 2 / g.
[0057] In this embodiment, the material undergoing decolorization treatment is ethyleneamine reactant 4, whose specific components are: 12.1 wt% EDA, 1.6 wt% PIP, 20.8 wt% MEA, 3.9 wt% DETA, 3.3 wt% AEEA, 2.3 wt% SMA, 5.9 wt% H2O, and 50.1 wt% NH3.
[0058] 16 kg of catalyst #3 was loaded into the decolorization reactor. Hydrogen and ethyleneamine reactant 4 were introduced and mixed online. The operating pressure was 15 MPa, the inlet temperature was 150 °C, and the temperature difference inside the decolorization reactor was controlled between 0 and 1 °C. The mixed stream entered the reactor, and the hydrogen volume hourly space velocity was controlled at 100 h⁻¹. -1 The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 0.5 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color of the ethyleneamine reactants decreased by 5 Hz before and after the decolorization treatment in this embodiment. During the decolorization treatment, the single-pass conversion rate of MEA was less than 0.5%.
[0059] Example 5
[0060] The decolorization process in this embodiment was tested using catalyst #4, a binary metal catalyst with an effective component of 15wt% Ni-0.75wt% Pt / Al₂O₃. The specific surface area of Al₂O₃ is 50-150 m². 2 / g.
[0061] In this embodiment, the material undergoing decolorization treatment is ethyleneamine reactant 5, whose specific components are: 13.4 wt% EDA, 1.5 wt% PIP, 20.2 wt% MEA, 4.0 wt% DETA, 3.3 wt% AEEA, 3.7 wt% SMA, 5.8 wt% H2O, and 48.1 wt% NH3.
[0062] 15.5 kg of catalyst #4 was loaded into the decolorization reactor. Hydrogen and ethyleneamine reactant 5 were introduced and mixed online. The operating pressure was 24 MPa, the inlet temperature was 135℃, and the temperature difference inside the decolorization reactor was controlled at 0-1℃. The mixed stream entered the reactor, and the hydrogen volume hourly space velocity was controlled at 150 h⁻¹. -1 The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 1.5 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color of the ethyleneamine reactants decreased by 55 Hz before and after the decolorization treatment in this embodiment. During the decolorization treatment, the single-pass conversion rate of MEA was less than 0.5%.
[0063] Comparative Example
[0064] In the comparative example, a blank catalyst was used.
[0065] The material used for decolorization treatment is the same as that in Example 1, namely ethyleneamine reactant 1, the specific composition of which is:
[0066] EDA 12.73wt%, PIP 1.58wt%, MEA 23.69wt%, DETA 3.74wt%, AEEA 3.16wt%, AEP 0.17wt%, HEP 0.15wt%, SMA 1.7wt%, H2O 6.56wt%, NH3 46.51wt%.
[0067] Ethyleneamine reactant 1 was introduced into the decolorization reactor at an operating pressure of 24 MPa and an inlet temperature of 195 °C. Hydrogen gas was introduced for online mixing, and the hydrogen volume hourly space velocity was controlled at 100 h⁻¹. -1 The liquid hourly space velocity (LHSV) of the ethyleneamine reactants is 1 h⁻¹. -1 By sampling and measuring the color of the inlet and outlet ethyleneamine reactants and comparing the results, it was found that the color remained essentially unchanged before and after treatment. Furthermore, even after adjusting the process operating parameters, the color of the mixed amine remained unchanged before and after treatment.
[0068] The experimental results of Examples 1-5 and the comparative examples are summarized in Table 1.
[0069] Table 1: Evaluation Results of Decolorization Effect of Ethyleneamine Reactants
[0070]
[0071] Note: The chromaticity unit Hz in Table 1 represents the Hazen chromaticity unit.
[0072] As can be seen from Examples 1-5 and Table 1, in the embodiments of the present invention, the decolorization treatment of the ethyleneamine reactants under catalyst and hydrogenation conditions can effectively reduce the color of the ethyleneamine reactants, while avoiding undesirable amination reactions during the decolorization process, thus not affecting the selective distribution of the target product in the ethyleneamine reactants.
[0073] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the term "comprising" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0074] The above embodiments are only used to illustrate the technical solutions of the present invention and should not be used to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments or equivalent substitutions can be made to some of the technical features without departing from the essence and scope of the present invention. Such modifications or equivalent substitutions still fall within the scope of the present invention.
Claims
1. A decolorization process for ethyleneamine reactants, characterized in that, The decolorization process includes: In the presence of hydrogen and a catalyst, ethyleneamine reactants undergo a decolorization reaction in a decolorization reactor. The catalyst includes a binary metal catalyst, wherein the main metal in the binary metal catalyst is Ni, and the auxiliary metal is selected from one or more of Ru, Re, Pt, and Pd. The temperature for the decolorization reaction is 100–240°C; The operating pressure of the decolorization reactor is 10–30 MPa.
2. The decolorization process as described in claim 1, wherein, The decolorization temperature range is 135–180°C.
3. The decolorization process as described in claim 1, wherein, The operating pressure of the decolorization reactor is 15–24 MPa.
4. The decolorization process as described in claim 1, wherein, The catalyst is a supported catalyst, and the support includes Al2O3 and / or SiO2.
5. The decolorization process as described in claim 4, wherein, The content of the main metal Ni ranges from 5 to 20 wt%, and the content of the auxiliary metal ranges from 0 to 2 wt%.
6. The decolorization process according to any one of claims 1 to 5, wherein, The ethyleneamine reactants comprise 20–70 wt% of a mixed ethyleneamine.
7. The process as described in claim 6, wherein, The ethyleneamine mixture includes EDA, PIP, MEA, DETA, AEEA, AEP, HEP, and SMA.
8. The decolorization process as described in claim 1, wherein, In the decolorization reaction, the single-pass conversion rate, based on MEA, is less than 2%.
9. The decolorization process as described in claim 7, wherein, The volume hourly space velocity (GHSV) of hydrogen is 100–500 h⁻¹. -1 The space velocity (WHSV) of the ethyleneamine reactant is 0.5–10 h⁻¹. -1 .
10. The decolorization process as described in claim 1, wherein, The temperature difference in the decolorization reactor is controlled between 0 and 1°C.