An apparatus and method for extracting high purity chemicals from coal tar wash oil fractions

Abstract

The present application relates to a kind of device and method for extracting high-purity chemicals from coal tar wash oil fraction, comprising: naphthalene separation column, methylnaphthalene separation unit, acenaphthene-fluorene-dibenzofuran separation unit;Methylnaphthalene separation unit includes methylnaphthalene separation tower, β-methylnaphthalene subunit and α-methylnaphthalene subunit connected in sequence;Acenaphthene-fluorene-dibenzofuran separation unit includes light removal tower, acenaphthene subunit, dibenzofuran subunit and fluorene subunit connected in sequence;The material outlet of the bottom of naphthalene separation column is connected with methylnaphthalene separation tower;The material outlet of the bottom of methylnaphthalene separation tower is connected with the material inlet of light removal tower.The device provided by the present application can effectively extract target chemicals in coal tar wash oil fraction by reasonable configuration of the device and coupling cooperation between devices, and obtain high-purity products.Compared with existing wash oil extraction chemical technology, it has higher efficiency, wider applicability and better product quality.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to an apparatus and method for extracting high-purity chemicals from coal tar wash oil fractions. Background Technology

[0002] Currently, coal tar is an important byproduct of coal processing. It is a complex mixture containing a large number of organic compounds, mainly including aromatic hydrocarbons, heterocyclic aromatic hydrocarbons, aliphatic compounds, and heteroatom compounds. The wash oil fraction is the portion of coal tar that is distilled between 230℃ and 300℃. The wash oil fraction contains many high-value-added chemicals, such as methylnaphthalene, β-methylnaphthalene, α-methylnaphthalene, acenaphthene, fluorene, and oxyfluorene. These chemicals can be used as monomeric raw materials in the electronics and information industry for producing electronic-grade products. They also have important applications in high-end dyes, pharmaceutical intermediates, and pigments.

[0003] However, wash oil is a complex multiphase mixture with a wide variety of components, containing ≥40 compounds, including numerous azeotropic systems, isomer systems, and special systems such as high- or low-boiling-point eutectics. The complexity of wash oil components and the presence of these special systems mean that it is nearly impossible to obtain high-purity chemicals using a single separation method. For example, the presence of azeotropes makes it ineffective to obtain high-purity products using a single distillation method; the presence of high / low-boiling-point eutectics limits the effectiveness of melt-crystallization separation; and the wide variety of chemicals restricts the use of adsorption separation methods.

[0004] In summary, the physicochemical properties of various chemicals in wash oil differ significantly. The separation process requires careful consideration of the characteristics of each substance, necessitating the use of different separation methods and steps, which increases the complexity and difficulty of the extraction process. Furthermore, most impurities affecting the high-purity extraction of target chemicals are trace amounts, requiring effective separation techniques to remove them from other components. This necessitates a highly efficient and selective extraction process. These challenges present significant difficulties for separating and extracting high-purity target chemicals from wash oil.

[0005] For example, CN101982523A discloses a continuous wash oil processing method. The separation process is carried out sequentially in four distillation columns (A, B, C, and D). The raw material wash oil is pumped into distillation column A. Naphthalene oil is collected at the top of the column, methylnaphthalene is collected on the side stream, and the residual oil at the bottom of the column is pumped into distillation column B. Medium wash oil is collected at the top of distillation column B, and acenaphthene fraction is collected on the side stream. After crystallization, industrial acenaphthene is obtained. The residual oil at the bottom of the column is pumped into distillation column C. Acenaphthene fraction is collected again at the top of distillation column C, and oxygen fluorene fraction is collected on the side stream. The residual oil at the bottom of the column is pumped into distillation column D. Oxyfluorene fraction is collected at the top of distillation column D, and fluorene fraction is collected on the side stream. The fluorene fraction is treated with solvent to obtain industrial fluorene.

[0006] For example, CN102268273A discloses a deep processing technology for coking wash oil. The raw material coking wash oil is passed sequentially through three continuous distillation columns, each with a side-stream outlet. It can extract in one step a naphthalene fraction containing more than 80% naphthalene, a β-methylnaphthalene fraction containing more than 70% β-methylnaphthalene, an α-methylnaphthalene fraction containing more than 60% α-methylnaphthalene, a medium wash oil, an acenaphthene fraction containing more than 60% acenaphthene, an oxygen fluorene fraction containing more than 55% oxygen fluorene, and a fluorene fraction containing more than 50% fluorene.

[0007] It is known that existing technologies can use side-stream sampling to cut raw materials into different components, and can achieve enrichment and cutting of different components in a single distillation column. However, they do not target the characteristics of the target components and impurities in the wash oil to achieve precise separation and extraction, and can only produce industrial-grade products with low purity (<98%). Summary of the Invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide an apparatus and method for extracting high-purity chemicals from coal tar wash oil fractions, which can solve the problems of poor separation effect and low product purity that still exist in the processing of coal tar wash oil fractions, and can simultaneously obtain high-purity chemical products of β-methylnaphthalene, α-methylnaphthalene, acenaphthene and fluorene.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an apparatus for extracting high-purity chemicals from coal tar wash oil fractions, the apparatus comprising:

[0011] Naphthalene separation tower, methylnaphthalene separation unit, acenaphthene-fluorene-oxyfluorene separation unit;

[0012] The methylnaphthalene separation unit comprises a methylnaphthalene separation tower, a β-methylnaphthalene subunit, and an α-methylnaphthalene subunit connected in sequence.

[0013] The acenaphthene-fluorene-oxyfluorene separation unit includes a light-light removal tower, an acenaphthene unit, an oxygen-fluorene unit, and a fluorene unit connected in sequence.

[0014] The bottom material outlet of the naphthalene separation tower is connected to the methylnaphthalene separation tower;

[0015] The bottom material outlet of the methylnaphthalene separation tower is connected to the material inlet of the light nitrate removal tower.

[0016] The apparatus provided by this invention, through its rational configuration and the coupling and cooperation between various devices, can effectively extract target chemicals from coal tar wash oil fractions, simultaneously obtaining multiple high-purity products. Furthermore, the design and optimization of each process step result in a highly efficient, selective, and economical processing technology. Compared to existing wash oil chemical extraction technologies, it offers higher efficiency, selectivity, wider applicability, and superior product quality.

[0017] Furthermore, the device provided by this invention can overcome the challenge of the huge differences in the physicochemical properties of the various components of wash oil: by fully considering the unique properties of each chemical, including boiling point, solubility, polarity, molecular size, etc., optimizing the combination of different separation technologies, and precisely designing separation operating conditions, so as to effectively obtain multiple (3 to 4) high-purity chemicals at the same time.

[0018] Furthermore, the device provided by this invention can achieve high-efficiency and high-selectivity separation: the separation process is precisely designed for specific systems and trace impurities to ensure high efficiency and high selectivity in separation, so that the target chemical is separated in high purity and the impurities are effectively removed.

[0019] As a preferred embodiment of the present invention, the β-methylnaphthalene subunit includes a first separation tower and a first purification tower.

[0020] Preferably, the α-methylnaphthalene subunit includes a second purification tower.

[0021] Preferably, the top material outlet of the methylnaphthalene separation tower is sequentially connected to the first separation tower and the first purification tower.

[0022] Preferably, the bottom material outlet of the first separation tower is connected to the second purification tower.

[0023] As a preferred embodiment of the present invention, the acenaphthene unit includes a second separation tower and a first purification tower connected in sequence.

[0024] Preferably, the fluorene subunit comprises a biphenyl debenzene tower, a second purification tower, and a first crystallization device connected in sequence.

[0025] Preferably, the fluorene unit includes a third refining tower and a second crystallization device connected in sequence.

[0026] As a preferred embodiment of the present invention, the bottom material outlet of the light-weight removal tower is connected to the feed inlet of the second separation tower.

[0027] Preferably, the top material outlet of the first refining tower is connected to the material inlet of the biphenyl removal tower.

[0028] Preferably, the bottom material outlet of the second refining tower is connected to the material inlet of the third refining tower.

[0029] Secondly, the present invention provides a method for extracting high-purity chemicals from coal tar wash oil fractions, the method comprising using the apparatus for extracting high-purity chemicals from coal tar wash oil fractions as described in the first aspect, specifically including:

[0030] Naphthalene is separated from the coal tar wash oil fraction to obtain naphthalene-free wash oil;

[0031] The obtained naphthalene-removing wash oil is subjected to methylnaphthalene separation to obtain the top methylnaphthalene material and the bottom material of the tower;

[0032] The obtained top methylnaphthalene material is subjected to a first separation, and the top material obtained from the first separation is subjected to a first purification to obtain high-purity β-methylnaphthalene. The bottom material obtained from the first separation is subjected to a second purification to obtain high-purity α-methylnaphthalene.

[0033] The obtained bottom material is subjected to light component removal, and the resulting bottom product is subjected to a second separation. The bottom product obtained from the second separation is subjected to a first purification to obtain a high-purity acenaphthene product. The top product obtained from the second separation is subjected to biphenyl removal, a second purification, and a first crystallization to obtain an oxyfluorene product. The bottom product obtained from the second purification is subjected to a third purification and a second crystallization to obtain a high-purity fluorene product.

[0034] As a preferred embodiment of the present invention, the pressure drop in the naphthalene separation tower is 0-100 kPa. Preferably, the number of trays in the naphthalene separation tower is 60-120.

[0035] Preferably, the reflux ratio in the naphthalene separation is 5-20.

[0036] Preferably, the top temperature of the naphthalene separation column is 120-200℃.

[0037] Preferably, the temperature of the bottom column in the naphthalene separation process is 200-300℃.

[0038] Preferably, the pressure drop in the methylnaphthalene separation tower is 0-100 kPa.

[0039] Preferably, the number of trays in the methylnaphthalene separation is 60-120.

[0040] Preferably, the reflux ratio in the methylnaphthalene separation is 8-25.

[0041] Preferably, the top temperature of the methylnaphthalene separation column is 120-230℃.

[0042] Preferably, the bottom temperature of the methylnaphthalene separation tower is 200-300℃.

[0043] As a preferred technical solution of the present invention, the pressure drop of the first purification tower is 0-100 kPa.

[0044] Preferably, the number of trays in the first purification process is 80-120.

[0045] Preferably, the reflux ratio in the first purification is 8-20.

[0046] Preferably, the temperature at the top of the column in the first purification process is 120-230℃.

[0047] Preferably, the temperature of the reboiler in the first purification process is 180-300℃.

[0048] Preferably, the pressure drop in the second purification tower is 0-50 kPa.

[0049] Preferably, the number of trays in the second purification process is 80-120.

[0050] Preferably, the reflux ratio in the second purification is 8-20.

[0051] Preferably, the temperature at the top of the column in the second purification process is 120-230℃.

[0052] Preferably, the temperature of the reboiler in the second purification process is 160-300℃.

[0053] As a preferred technical solution of the present invention, the pressure drop of the tower in the process of removing light components is 0-30 kPa.

[0054] Preferably, the number of trays in the light component removal process is 80-120.

[0055] Preferably, the reflux ratio in the light component is 10-30.

[0056] Preferably, the temperature at the top of the column during the removal of light components is 120-230°C.

[0057] Preferably, the bottom temperature of the column for removing light components is 160-300℃.

[0058] Preferably, the pressure drop in the resulting second separation tower is 0-30 kPa.

[0059] Preferably, the number of trays in the resulting second separation is 80-120.

[0060] Preferably, the reflux ratio in the resulting second separation is 10-30.

[0061] Preferably, the temperature at the top of the second separator is 110-230℃.

[0062] Preferably, the temperature of the second separation column is 160-300℃.

[0063] As a preferred technical solution of the present invention, the pressure drop of the first refining tower is 0-30 kPa.

[0064] Preferably, the number of trays in the first refining process is 80-120.

[0065] Preferably, the reflux ratio in the first refining process is 15-35.

[0066] Preferably, the temperature at the top of the first refining column is 130-230℃.

[0067] Preferably, the temperature of the first refining column is 200-300℃.

[0068] Preferably, the pressure drop in the biphenyl removal tower is 10-50 kPa.

[0069] Preferably, the number of trays in the biphenyl removal process is 80-120.

[0070] Preferably, the reflux ratio in the debiphenyl is 8-30.

[0071] Preferably, the temperature at the top of the column in the biphenyl removal process is 130-230°C.

[0072] Preferably, the temperature of the reboiler in the biphenyl removal tower is 200-300℃.

[0073] As a preferred technical solution of the present invention, the pressure drop of the second refining tower is 10-50 kPa.

[0074] Preferably, the number of trays in the second refining process is 80-120.

[0075] Preferably, the reflux ratio in the second refining process is 10-30.

[0076] Preferably, the temperature at the top of the tower in the second refining process is 150-260°C.

[0077] Preferably, the temperature of the reboiler in the second refining process is 200-300℃;

[0078] Preferably, the volume concentration of the raw material solution in the first crystallization is 5-20%;

[0079] Preferably, the temperature in the first crystallization is 0-25°C;

[0080] Preferably, the cooling rate in the first crystallization is 1-5°C / min;

[0081] Preferably, the stirring speed in the first crystallization is 50-200 r / min;

[0082] Preferably, the pressure drop in the third refining process is 10-50 kPa;

[0083] Preferably, the reflux ratio in the third refining process is 8-30;

[0084] Preferably, the temperature at the top of the column in the third refining process is 130-230°C;

[0085] Preferably, the temperature at the top of the column in the third refining process is 200-300°C;

[0086] Preferably, the crystallization temperature in the second crystal is -10 to 25°C;

[0087] Preferably, the cooling rate in the second crystallization is 0.1-3 °C / min;

[0088] Preferably, the stirring speed during the second crystallization is 50-200 r / min;

[0089] Preferably, the crystallization time of the second crystal is 1-24 hours.

[0090] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0091] (1) This invention designs a combined processing technology to extract and separate chemicals from coal tar wash oil fractions according to a specific process, achieving high-purity extraction of multiple target chemicals. Compared with traditional single extraction processes, the combined processing technology of this invention is more comprehensive and efficient, and can simultaneously obtain multiple high-purity chemicals, improving the value and utilization efficiency of the products.

[0092] (2) This invention employs a multi-stage separation and purification strategy, setting up corresponding separation and purification towers for different chemicals. Through step-by-step purification, impurities and mixtures can be effectively removed, improving the purity of the target chemical. This multi-stage separation and purification method is more refined and precise, enabling the acquisition of highly pure chemicals.

[0093] (3) In this invention, by-products are effectively utilized through a rationally designed process flow. For example, medium-quality wash oil can be sold directly as a benzene washing agent, and the residual oil in the bottom of the acenaphthene refining tower and the fluorene refining tower can be used to produce carbon black and other products. This not only improves the overall economic efficiency of the process but also reduces waste generation, which is in line with the concept of sustainable development.

[0094] (4) This invention ensures the high purity of the target chemicals by optimizing each process step. For example, β-methylnaphthalene and α-methylnaphthalene are purified to obtain high-purity products with a purity ≥99% through purification towers. This is of great significance for many fields that require high-purity chemicals, such as the pharmaceutical and electronics industries, as it can provide more reliable and high-quality raw materials. Attached Figure Description

[0095] Figure 1 This is a schematic diagram of an apparatus for extracting high-purity chemicals from coal tar wash oil fractions, provided in an embodiment of the present invention.

[0096] In the diagram: 1-Naphthalene separation tower, 2-Methylnaphthalene separation tower, 3-First separation tower, 4-First purification tower, 5-Second purification tower, 6-Light ions removal tower, 7-Second separation tower, 8-First refining tower, 9-Biphenyl removal tower, 10-Second refining tower, 11-First crystallization equipment, 12-Third refining tower, 13-Second crystallization equipment;

[0097] O-Coal tar wash oil fraction, A-Naphthalene oil, B-Crude naphthalene, C-β-methylnaphthalene, D-α-methylnaphthalene, E-Medium wash oil, F-Biphenyl, G-Oxyfluorene, H-Fluorene, J-Acenaphthene, K-Heavy residual oil.

[0098] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0099] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0100] This embodiment provides an apparatus for extracting high-purity chemicals from coal tar wash oil fractions, such as... Figure 1 As shown, the device includes:

[0101] Naphthalene separation tower 1, methylnaphthalene separation unit, acenaphthene-fluorene-oxyfluorene separation unit;

[0102] The methylnaphthalene separation unit includes a methylnaphthalene separation tower 2, a β-methylnaphthalene subunit, and an α-methylnaphthalene subunit connected in sequence.

[0103] The acenaphthene-fluorene-oxyfluorene separation unit includes a light-light removal tower 6, an acenaphthene subunit, an oxygen-fluorene subunit, and a fluorene subunit connected in sequence.

[0104] The bottom material outlet of the naphthalene separation tower 1 is connected to the methylnaphthalene separation tower 2;

[0105] The bottom material outlet of the methylnaphthalene separation tower 2 is connected to the material inlet of the light nitrate removal tower 6.

[0106] Specifically, the β-methylnaphthalene subunit includes a first separation tower 3 and a first purification tower 4.

[0107] Specifically, the α-methylnaphthalene subunit includes a second purification tower 5.

[0108] Specifically, the top material outlet of the methylnaphthalene separation tower 2 is sequentially connected to the first separation tower 3 and the first purification tower 4.

[0109] Specifically, the bottom material outlet of the first separation tower 3 is connected to the second purification tower 5.

[0110] Specifically, the acenaphthene unit includes a second separation tower 7 and a first refining tower 8 connected in sequence.

[0111] Specifically, the oxygen fluorene subunit includes a biphenyl debenzene tower 9, a second purification tower 10, and a first crystallization device 11 connected in sequence.

[0112] Specifically, the fluorene unit includes a third refining tower 12 and a second crystallization device 13 connected in sequence.

[0113] Specifically, the bottom material outlet of the light-weight removal tower 6 is connected to the feed inlet of the second separation tower 7.

[0114] Specifically, the top material outlet of the first refining tower 8 is connected to the material inlet of the biphenyl removal tower 9.

[0115] Specifically, the bottom material outlet of the second refining tower 10 is connected to the material inlet of the third refining tower 12.

[0116] Among them, after the coal tar wash oil fraction O is processed by naphthalene separation tower 1, naphthalene oil A is obtained at the top of the tower, which can be sold as a benzene washing agent or used as a raw material for other processes; crude naphthalene B is obtained from the side stream, which can be sold directly as an industrial naphthalene product or used as a raw material for other processes.

[0117] Among them, the top of the first purification tower 4 produces high-purity β-methylnaphthalene C, and the bottom produces medium-quality wash oil E.

[0118] Among them, the high-purity product of α-methylnaphthalene D is collected from the top of the second purification tower 5, and the medium-quality wash oil E is collected from the top of the tower.

[0119] Among them, medium-quality wash oil E is extracted from the top of light oil removal tower 6, and biphenyl is extracted from the top of biphenyl removal tower 9.

[0120] The first refining tower 8 produces a high-purity product of acenaphthene J, the first crystallization equipment 11 produces a high-purity product of fluorene oxide G, and the second crystallization equipment 13 produces a high-purity product of fluorene H.

[0121] In this invention, the material fed into each tower can be selected to be fed from the middle of the tower. If the product purity can meet the requirements, it is also acceptable to feed from the gas position of the tower.

[0122] Furthermore, the present invention provides a method for extracting high-purity chemicals from coal tar wash oil fractions based on the aforementioned apparatus, the method comprising:

[0123] Naphthalene is separated from the coal tar wash oil fraction to obtain naphthalene-free wash oil;

[0124] The obtained naphthalene-removing wash oil is subjected to methylnaphthalene separation to obtain the top methylnaphthalene material and the bottom material of the tower;

[0125] The obtained top methylnaphthalene material is subjected to a first separation, and the top material obtained from the first separation is subjected to a first purification to obtain high-purity β-methylnaphthalene. The bottom material obtained from the first separation is subjected to a second purification to obtain high-purity α-methylnaphthalene.

[0126] The obtained bottom material is subjected to light component removal, and the resulting bottom product is subjected to a second separation. The bottom product obtained from the second separation is subjected to a first purification to obtain a high-purity acenaphthene product. The top product obtained from the second separation is subjected to biphenyl removal, a second purification, and a first crystallization to obtain an oxyfluorene product. The bottom product obtained from the second purification is subjected to a third purification and a second crystallization to obtain a high-purity fluorene product.

[0127] In this invention, "high purity" refers to a product purity of ≥99%.

[0128] Specifically, the pressure drop in the naphthalene separation tower is 0-100 kPa, for example, it can be 0 kPa, 20 kPa, 40 kPa, 60 kPa, 80 kPa or 100 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0129] Specifically, the number of trays in the naphthalene separation is 60-120, for example, it can be 60, 70, 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0130] Specifically, the reflux ratio in the naphthalene separation is 5-20, for example, it can be 5, 10, 15 or 20, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0131] Specifically, the top temperature of the naphthalene separation column is 120-200℃, for example, it can be 120℃, 140℃, 160℃, 180℃ or 200℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0132] Specifically, the temperature of the reboiler in the naphthalene separation process is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0133] Specifically, the pressure drop in the methylnaphthalene separation tower is 0-100 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa, 40 kPa, 60 kPa, 80 kPa or 100 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0134] Specifically, the number of trays in the methylnaphthalene separation process is 60-120, for example, it can be 60, 70, 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0135] Specifically, the reflux ratio in the separation of methylnaphthalene is 8-25, for example, it can be 8, 10, 15, 20 or 25, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0136] Specifically, the top temperature of the column in the methylnaphthalene separation process is 120-230℃, for example, it can be 120℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0137] Specifically, the temperature of the bottom column in the methylnaphthalene separation process is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0138] Specifically, the pressure drop in the first purification tower is 0-100 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa, 40 kPa, 60 kPa, 80 kPa or 100 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0139] Specifically, the number of trays in the first purification process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0140] Specifically, the reflux ratio in the first purification is 8-20, for example, it can be 8, 10, 12, 14, 16, 18 or 20, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0141] Specifically, the temperature at the top of the column in the first purification process is 120-230℃, for example, it can be 120℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0142] Specifically, the temperature of the reboiler in the first purification process is 180-300℃, for example, it can be 180℃, 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0143] Specifically, the pressure drop in the second purification tower is 0-50 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa or 50 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0144] Specifically, the number of trays in the second purification process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0145] Specifically, the reflux ratio in the second purification is 8-20, for example, it can be 8, 10, 12, 14, 16, 18 or 20, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0146] Specifically, the top temperature of the column in the second purification process is 120-230℃, for example, it can be 120℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0147] Specifically, the temperature of the reboiler in the second purification process is 160-300℃, for example, it can be 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0148] Specifically, the pressure drop in the tower during the removal of light components is 0-30 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa or 30 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0149] Specifically, the number of trays in the light component removal process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0150] Specifically, the reflux ratio in the light component is 10-30, for example, it can be 10, 15, 20, 25 or 30, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0151] Specifically, the temperature at the top of the column during the removal of light components is 120-230℃, for example, it can be 120℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0152] Specifically, the temperature of the reboiler in the light component removal process is 160-300℃, for example, it can be 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0153] Specifically, the pressure drop in the second separation tower is 0-30 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa or 30 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0154] Specifically, the number of trays in the resulting second separation is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0155] Specifically, the reflux ratio in the resulting second separation is 10-30, for example, it can be 10, 15, 20, 25 or 30, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0156] Specifically, the top temperature of the column in the second separation is 110-230℃, for example, it can be 110℃, 120℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0157] Specifically, the temperature of the second separation column is 160-300℃, for example, it can be 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0158] Specifically, the pressure drop in the first refining tower is 0-30 kPa, for example, it can be 0 kPa, 10 kPa, 20 kPa or 30 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0159] Specifically, the number of trays in the first refining process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0160] Specifically, the reflux ratio in the first refining process is 15-35, for example, it can be 15, 20, 25, 30 or 35, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0161] Specifically, the temperature at the top of the column in the first refining process is 130-230℃, for example, it can be 130℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0162] Specifically, the temperature of the reboiler in the first refining process is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0163] Specifically, the pressure drop in the debiphenyl tower is 10-50 kPa, for example, it can be 10 kPa, 20 kPa, 30 kPa, 40 kPa or 50 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0164] Specifically, the number of plates in the debiphenyl process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0165] Specifically, the reflux ratio in the debiphenyl is 8-30, for example, it can be 8, 10, 15, 20, 25 or 30, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0166] Specifically, the top temperature of the debiphenyl tower is 130-230℃, for example, it can be 130℃, 140℃, 160℃, 180℃, 200℃, 220℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0167] Specifically, the temperature of the reboiler in the biphenyl removal tower is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0168] Specifically, the pressure drop in the second refining tower is 10-50 kPa, for example, it can be 10 kPa, 20 kPa, 30 kPa, 40 kPa, or 50 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0169] Specifically, the number of trays in the second refining process is 80-120, for example, it can be 80, 90, 100, 110 or 120, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0170] Specifically, in the second refining process, the reflux ratio is 10-30, for example, it can be 10, 15, 20, 25 or 30, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0171] Specifically, the top temperature of the tower in the second refining process is 150-260°C, for example, it can be 150°C, 160°C, 180°C, 200°C, 220°C, 240°C or 260°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0172] Specifically, the temperature of the reboiler in the second refining process is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0173] Specifically, the volume concentration of the raw material liquid in the first crystallization is 5-20%, for example, it can be 5%, 10%, 15% or 20%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0174] Specifically, the temperature in the first crystallization is 0-25℃, for example, it can be 0℃, 5℃, 10℃, 15℃, 20℃ or 25℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0175] Specifically, the cooling rate in the first crystallization is 1-5℃ / min, for example, it can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0176] Specifically, the stirring speed in the first crystallization is 50-200 r / min, for example, it can be 50 r / min, 100 r / min, 150 r / min or 200 r / min, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0177] Specifically, the pressure drop in the third refining process is 10-50 kPa, for example, it can be 10 kPa, 20 kPa, 30 kPa, 40 kPa or 50 kPa, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0178] Specifically, the reflux ratio in the third refining process is 8-30, for example, it can be 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 or 30, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0179] Specifically, the top temperature of the tower in the third refining process is 130-230℃, for example, it can be 130℃, 150℃, 170℃, 190℃, 210℃ or 230℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0180] Specifically, the top temperature of the tower in the third refining process is 200-300℃, for example, it can be 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0181] Specifically, the crystallization temperature in the second crystal is -10 to 25°C, for example, it can be -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C or 25°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0182] Specifically, the cooling rate in the second crystallization is 0.1-3℃ / min, for example, it can be 0.1℃ / min, 0.5℃ / min, 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min or 3℃ / min, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0183] Specifically, the stirring speed in the second crystallization is 50-200 r / min, for example, it can be 50 r / min, 100 r / min, 150 r / min or 200 r / min, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0184] Specifically, the crystallization time of the second crystal is 1-24h, for example, it can be 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0185] To further illustrate the superior performance of the apparatus for extracting high-purity chemicals from coal tar wash oil fractions provided by the present invention, the following specific usage examples are provided: Specific Implementation

[0187] In this embodiment, 1000 kg of coal tar wash oil fraction at 230-300℃ was used as raw material. The mass percentage of each target component in the wash oil raw material is detailed in Table 1.

[0188] Table 1

[0189] Naphthalene / % α-Methylnaphthalene / % β-Methylnaphthalene / % Acenaphthene / % Dibenzofuran / % Fluorene / % 3 5 10 15 10 20

[0190] The wash oil feedstock first enters a naphthalene separation tower for naphthalene separation. Naphthalene oil fraction is collected from the top of the naphthalene separation tower. Crude naphthalene with a purity ≥95% is collected from the upper side stream of the denaphthalene removal tower. The denaphthalene-removed wash oil from the bottom of the denaphthalene removal tower enters a methylnaphthalene separation tower for methylnaphthalene separation. The light fraction is collected from the top of the methylnaphthalene separation tower and enters the first separation tower, while the heavy fraction from the bottom enters the light fraction removal tower. β-methylnaphthalene is collected from the top of the first separation tower and enters the first purification tower. High-purity β-methylnaphthalene product with a purity ≥99% is collected from the top of the first purification tower.

[0191] After being collected from the bottom of the first separation tower, α-methylnaphthalene enters the second purification tower, and high-purity α-methylnaphthalene product with a purity of ≥99% is collected from the top of the second purification tower.

[0192] The medium-quality wash oil is extracted from the top of the light benzene removal tower and sold directly as a benzene washing agent.

[0193] The heavy fraction rich in acenaphthene, fluorene, and oxyfluorene is collected from the bottom of the light fraction removal tower and enters the second separation tower. The acenaphthene-rich component is collected from the bottom of the second separation tower and enters the first purification tower for purification to obtain a high-purity acenaphthene product with a purity of ≥99%.

[0194] The components rich in fluorene, fluorene oxyfluorene, and biphenyl are collected from the top of the second separation tower and then enter the biphenyl removal tower to remove biphenyl before entering the second purification tower. The crude fluorene oxyfluorene is collected from the top of the second purification tower and then enters the fluorene oxyfluorene crystallization section. After the first crystallization, centrifugation, and drying, fluorene oxyfluorene product with a purity of ≥95% is obtained.

[0195] After the crude fluorene fraction is collected from the top of the third refining column, it enters the fluorene crystallization section. After second crystallization, centrifugation, and drying, a high-purity fluorene product with a purity of ≥99% is obtained.

[0196] The following are specific embodiments based on the above process. The operating parameters and product results of the embodiments are detailed below:

[0197] Example 1 is shown in Table 1 below.

[0198] Table 1

[0199]

[0200]

[0201]

[0202] Example 2 is shown in Table 2 below.

[0203] Table 2

[0204]

[0205]

[0206] Example 3 is shown in Table 3 below.

[0207] Table 3

[0208]

[0209]

[0210]

[0211] Example 4 is shown in Table 4 below.

[0212] Table 4

[0213]

[0214]

[0215] Comparative Example 1

[0216] The only difference from Example 1 is that naphthalene separation is not performed, i.e., no naphthalene separation tower is installed; the material is directly fed into the methylnaphthalene separation tower. The performance indicators of the obtained product are detailed in Table 5.

[0217] Table 5

[0218] Rectifying column Top product Yield / % Output / kg Purity / % First purification column β-Methylnaphthalene 78 32 97.3 Second purification column α-Methylnaphthalene 76 91.0 97.0 Second separation column Acenaphthene concentrated solution —— —— 96.3 First refining column Acenaphthene essential oil 68 132 99.2 Diphenyl removal column Diphenyl 75 17.2 99.3 Second refining column Dibenzofuran 86 85 90.0 First crystallization High-purity dibenzofuran 88 63.75 99.6 Third refining column Fluorene 85 176 95.0 Second crystallization High-purity fluorene 88 126.72 99.7 Medium-quality wash oil 209.98 Heavy residual oil 327.35

[0219] Comparative Example 2

[0220] The only difference from Example 1 is that biphenyl removal is not performed, i.e., no biphenyl removal tower is installed. In this case, the top material of the second separation tower is directly fed into the second purification tower. The performance indicators of the obtained product are detailed in Table 6.

[0221] Table 6

[0222]

[0223]

[0224] The results of the above embodiments demonstrate that the present invention can effectively extract target chemicals from coal tar wash oil fractions and obtain high-purity products. Furthermore, the design and optimization of each process step make the entire processing technology highly efficient and economical, offering higher efficiency, wider applicability, and superior product quality compared to existing wash oil chemical extraction technologies.

[0225] The present invention is described above through the embodiments to illustrate its detailed structural features, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0226] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0227] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0228] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An apparatus for extracting high-purity chemicals from coal tar wash oil fractions, characterized in that, The apparatus for extracting high-purity chemicals from coal tar wash oil fractions includes: Naphthalene separation tower, methylnaphthalene separation unit, acenaphthene-fluorene-oxyfluorene separation unit; The methylnaphthalene separation unit comprises a methylnaphthalene separation tower, a β-methylnaphthalene subunit, and an α-methylnaphthalene subunit connected in sequence. The acenaphthene-fluorene-oxyfluorene separation unit comprises a light fluoride removal tower, an acenaphthene unit, an oxygen fluorene unit, and a fluorene unit connected in sequence. The acenaphthene unit comprises a second separation tower and a first purification tower connected in sequence. The oxygen fluorene unit comprises a biphenyl removal tower, a second purification tower, and a first crystallization device connected in sequence. The fluorene unit comprises a third purification tower and a second crystallization device connected in sequence. The bottom material outlet of the light fluoride removal tower is connected to the inlet of the second separation tower. The top material outlet of the second separation tower is connected to the inlet of the biphenyl removal tower. The bottom material outlet of the second purification tower is connected to the inlet of the third purification tower. The bottom material outlet of the naphthalene separation tower is connected to the methylnaphthalene separation tower; The bottom material outlet of the methylnaphthalene separation tower is connected to the material inlet of the light nitrate removal tower.

2. The apparatus for extracting high-purity chemicals from coal tar wash oil fraction as described in claim 1, characterized in that, The β-methylnaphthalene subunit includes a first separation tower and a first purification tower.

3. The apparatus for extracting high-purity chemicals from coal tar wash oil fraction as described in claim 2, characterized in that, The α-methylnaphthalene subunit includes a second purification tower.

4. The apparatus for extracting high-purity chemicals from coal tar wash oil fraction as described in claim 2, characterized in that, The top material outlet of the methylnaphthalene separation tower is sequentially connected to the first separation tower and the first purification tower.

5. The apparatus for extracting high-purity chemicals from coal tar wash oil fraction as described in claim 3, characterized in that, The bottom material outlet of the first separation tower is connected to the second purification tower.

6. A method for extracting high-purity chemicals from coal tar wash oil fractions, characterized in that, The method includes using the apparatus described in any one of claims 1-5 for extracting high-purity chemicals from coal tar wash oil fractions, specifically comprising: Naphthalene is separated from the coal tar wash oil fraction to obtain naphthalene-free wash oil; The obtained naphthalene-removing wash oil is subjected to methylnaphthalene separation to obtain the top methylnaphthalene material and the bottom material of the tower; The obtained top methylnaphthalene material is subjected to a first separation, and the top material obtained from the first separation is subjected to a first purification to obtain high-purity β-methylnaphthalene. The bottom material obtained from the first separation is subjected to a second purification to obtain high-purity α-methylnaphthalene. The obtained bottom material is subjected to light component removal, and the resulting bottom product is subjected to a second separation. The bottom product obtained from the second separation is subjected to a first purification to obtain a high-purity acenaphthene product. The top product obtained from the second separation is subjected to biphenyl removal, a second purification, and a first crystallization to obtain an oxyfluorene product. The bottom product obtained from the second purification is subjected to a third purification and a second crystallization to obtain a high-purity fluorene product.

7. The method as described in claim 6, characterized in that, The pressure drop in the naphthalene separation tower is 0-100 kPa.

8. The method as described in claim 6, characterized in that, The number of trays in the naphthalene separation is 60-120.

9. The method as described in claim 6, characterized in that, The reflux ratio in the naphthalene separation is 5-20.

10. The method as described in claim 6, characterized in that, The top temperature of the naphthalene separation column is 120-200℃.

11. The method as described in claim 6, characterized in that, The temperature of the bottom column in the naphthalene separation process is 200-300℃.

12. The method as described in claim 6, characterized in that, The pressure drop in the methylnaphthalene separation tower is 0-100 kPa.

13. The method as described in claim 6, characterized in that, The number of trays in the methylnaphthalene separation is 60-120.

14. The method as described in claim 6, characterized in that, The reflux ratio in the methylnaphthalene separation is 8-25.

15. The method as described in claim 6, characterized in that, The temperature at the top of the column during the methylnaphthalene separation is 120-230℃.

16. The method as described in claim 6, characterized in that, The temperature of the bottom column in the methylnaphthalene separation process is 200-300℃.

17. The method as described in claim 6, characterized in that, The pressure drop in the first purification tower is 0-100 kPa.

18. The method as described in claim 6, characterized in that, The number of trays in the first purification process is 80-120.

19. The method as described in claim 6, characterized in that, The reflux ratio in the first purification process is 8-20.

20. The method as described in claim 6, characterized in that, The temperature at the top of the column in the first purification process is 120-230℃.

21. The method as described in claim 6, characterized in that, The temperature of the reboiler in the first purification process is 180-300℃.

22. The method as described in claim 6, characterized in that, The pressure drop in the second purification tower is 0-50 kPa.

23. The method as described in claim 6, characterized in that, The number of trays in the second purification process is 80-120.

24. The method as described in claim 6, characterized in that, The reflux ratio in the second purification process is 8-20.

25. The method as described in claim 6, characterized in that, The temperature at the top of the column in the second purification process is 120-230℃.

26. The method as described in claim 6, characterized in that, The temperature of the reboiler in the second purification process is 160-300℃.

27. The method as described in claim 6, characterized in that, The pressure drop in the tower during the removal of light components is 0-30 kPa.

28. The method as described in claim 6, characterized in that, The number of trays in the light component removal section is 80-120.

29. The method as described in claim 6, characterized in that, The reflux ratio in the light component is 10-30.

30. The method as described in claim 6, characterized in that, The temperature at the top of the column during the removal of light components is 120-230℃.

31. The method as described in claim 6, characterized in that, The temperature of the bottom column in the light component removal process is 160-300℃.

32. The method as described in claim 6, characterized in that, The pressure drop in the second separation column is 0-30 kPa.

33. The method as described in claim 6, characterized in that, The number of trays in the second separation is 80-120.

34. The method as described in claim 6, characterized in that, The reflux ratio in the resulting second separation is 10-30.

35. The method as described in claim 6, characterized in that, The temperature at the top of the column in the second separation was 110-230℃.

36. The method as described in claim 6, characterized in that, The temperature of the bottom column in the second separation process is 160-300℃.

37. The method as described in claim 6, characterized in that, The pressure drop in the first refining tower is 0-30 kPa.

38. The method as described in claim 6, characterized in that, The first refining process involves 80-120 trays.

39. The method as described in claim 6, characterized in that, The reflux ratio in the first refining process is 15-35.

40. The method as described in claim 6, characterized in that, The temperature at the top of the first refining column is 130-230℃.

41. The method as described in claim 6, characterized in that, The temperature of the first refining column is 200-300℃.

42. The method as described in claim 6, characterized in that, The pressure drop in the debiphenyl tower is 10-50 kPa.

43. The method as described in claim 6, characterized in that, The number of trays in the debiphenyl-deionized tower is 80-120.

44. The method as described in claim 6, characterized in that, The reflux ratio in the debiphenyl is 8-30.

45. The method as described in claim 6, characterized in that, The temperature at the top of the column in the biphenyl debenzene decontamination process is 130-230℃.

46. ​​The method as described in claim 6, characterized in that, The temperature of the reboiler in the biphenyl debenzene debenzene tower is 200-300℃.

47. The method as described in claim 6, characterized in that, The pressure drop in the second refining tower is 10-50 kPa.

48. The method as described in claim 6, characterized in that, The number of trays in the second refining process is 80-120.

49. The method as described in claim 6, characterized in that, The reflux ratio in the second refining process is 10-30.

50. The method as described in claim 6, characterized in that, The temperature at the top of the tower in the second refining process is 150-260℃.

51. The method as described in claim 6, characterized in that, The temperature of the retort in the second refining process is 200-300℃.

52. The method as described in claim 6, characterized in that, The volume concentration of the raw material solution in the first crystallization is 5-20%.

53. The method as described in claim 6, characterized in that, The temperature in the first crystal is 0-25℃.

54. The method as described in claim 6, characterized in that, The cooling rate in the first crystallization is 1-5℃ / min.

55. The method as described in claim 6, characterized in that, The stirring speed in the first crystallization is 50-200 r / min.

56. The method as described in claim 6, characterized in that, The pressure drop in the third refining process is 10-50 kPa.

57. The method as described in claim 6, characterized in that, The reflux ratio in the third refining process is 8-30.

58. The method as described in claim 6, characterized in that, The temperature at the top of the tower in the third refining process is 130-230℃.

59. The method as described in claim 6, characterized in that, The temperature at the top of the tower in the third refining process is 200-300℃.

60. The method as described in claim 6, characterized in that, The crystallization temperature in the second crystal is -10~25℃.

61. The method as described in claim 6, characterized in that, The cooling rate in the second crystallization is 0.1-3℃ / min.

62. The method as described in claim 6, characterized in that, The stirring speed during the second crystallization is 50-200 r / min.

63. The method as described in claim 6, characterized in that, The crystallization time for the second crystal is 1-24 hours.

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