A continuous refining device and method for crude phenol

Abstract

The present invention discloses a continuous refining device and method for crude phenol, the device comprises a crude phenol storage tank, a dehydration tower, a primary distillation tower, a phenol fraction tower, an o-cresol fraction tower, a m-cresol tower, an extractive distillation tower and a p-cresol fraction tower connected in sequence, and the top of each tower is individually connected to a cooler; the method specifically comprises the following steps: (1) discharging phenol water; (2) discharging heavy fractions; (3) discharging phenol; (4) discharging o-cresol; (5) discharging residual oil at the bottom of the tower; (6) extractive distillation, discharging m-cresol; (7) discharging p-cresol, and recycling the extractant. Compared with the traditional continuous distillation process, the present invention uses vacuum distillation to separate the components, and the obtained product separation degree is higher, and the theoretical plate number and energy consumption are less, so that high-purity phenol products can be produced with low energy consumption, low cost and high efficiency, which greatly improves the economic and environmental benefits.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and more particularly to a continuous refining device and method for crude phenol. Background Art

[0002] In the industrial process of coal-to-natural gas, a large amount of by-products such as crude phenol are often produced. Since crude phenol contains a variety of non-phenolic organic impurities such as sulfur and nitrogen, the product quality is relatively poor and the market sales are limited. Therefore, it is necessary to refine the crude phenol to increase the product value before selling it.

[0003] Crude phenol refining is a process based on the boiling point difference of phenolic compounds themselves, and uses distillation separation to process crude phenol to obtain various phenolic products with higher purity. Crude phenol contains substances such as phenol, o-cresol, m-cresol and xylenol, which are all important chemical raw materials. Among them, phenol is commonly used in the production of bisphenol A, phenolic resin, epoxy resin, synthetic fiber and disinfectant, etc., o-cresol can be used to produce plant protection agents, hormone-type rust removers, synthetic preservatives, lubricants, etc., m-p-cresol can be used to produce lubricant additives, paints, pesticides, etc., and xylenol can be used to produce preservatives, fungicides, pesticides, dyes, etc.

[0004] At present, the process of crude phenol refining can be divided into two categories: continuous distillation and intermittent distillation. Among them, continuous distillation is to make the crude phenol after dehydration and deslagging enter the phenol tower, o-cresol tower and m-cresol tower in the order of boiling point from low to high, and obtain phenol, o-cresol and m-cresol at the top of the tower in turn. The process is simple, but the purity of the product is low and the price is relatively low. Intermittent distillation can produce products with higher purity and bring higher profits, but it also has defects such as small processing capacity, long production cycle, low product yield and complex operation.

[0005] Therefore, how to develop a crude phenol purification method with simple operation and good separation effect is an urgent problem to be solved by technicians in this field. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a continuous refining device and method for crude phenol, so as to solve the problems of low purity of continuous distillation products and high production cost of intermittent distillation in the prior art.

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

[0008] A continuous refining device for crude phenol comprises a crude phenol storage tank, a dehydration tower, a primary distillation tower, a phenol fraction tower, an o-cresol fraction tower, an m-p-cresol tower, an extractive distillation tower and a p-cresol fraction tower which are connected in sequence, and the top of each tower is individually connected with a cooler.

[0009] Furthermore, the above coolers are all connected to a vacuum system.

[0010] A method for continuous refining of crude phenol, using the above-mentioned continuous refining device, specifically comprises the following steps:

[0011] (1) The crude phenol in the crude phenol storage tank is preheated and then transported to the dehydration tower. The top product is condensed in a cooler, part of which is refluxed to the dehydration tower, and the remaining part is discharged as phenol water. The bottom product is transported to the primary distillation tower;

[0012] (2) The heavy fraction is discharged from the bottom of the primary distillation tower, and the top product is condensed in a cooler, part of which is refluxed to the primary distillation tower, and the rest is transported to the phenol fractionation tower;

[0013] (3) After the top product of the phenol fraction tower is condensed in a cooler, part of it is refluxed to the phenol fraction tower, and the remaining part is discharged as phenol. The bottom product is transported to the o-cresol fraction tower;

[0014] (4) The top product of the o-cresol fraction tower is condensed in a cooler, part of which is refluxed to the o-cresol fraction tower, and the remaining o-cresol is discharged, and the bottom product is transported to the m-cresol tower;

[0015] (5) The residual oil at the bottom of the meta-cresol tower is discharged, and the top product is condensed in a cooler, part of which is refluxed to the meta-cresol tower, and the rest is transported to the extractive distillation tower;

[0016] (6) adding an extractant to the top of the extractive distillation tower for extractive distillation, condensing the top product in a cooler, partially refluxing to the extractive distillation tower, discharging the remaining m-cresol, and conveying the bottom product to a p-cresol fractionation tower;

[0017] (7) The top product of the p-cresol fraction tower is condensed in a cooler, part of which is refluxed to the p-cresol fraction tower, and the remaining p-cresol is discharged. The extractant at the bottom of the tower is refluxed to the extraction distillation tower for recycling.

[0018] Furthermore, in the above step (1), the heat of the dehydration tower is provided by heat transfer oil.

[0019] A further beneficial effect of adopting the above method is that there is no need for high-power heating, energy consumption is low, and waste heat generated in subsequent work stages can be utilized to reduce operating costs and environmental pollution.

[0020] Furthermore, in the above step (2), the primary distillation tower adopts vacuum distillation, the operating pressure is 0.0001~0.05MPa, and the reflux ratio is (5~30):1.

[0021] Furthermore, in the above step (3), the phenol fractionation tower adopts vacuum distillation, the operating pressure is 0.0001~0.08MPa, and the reflux ratio is (4~25):1.

[0022] Furthermore, in the above step (4), the o-cresol fraction tower adopts vacuum distillation, the operating pressure is 0.0001~0.03MPa, and the reflux ratio is (8~50):1.

[0023] Furthermore, in the above step (5), the m-cresol tower adopts vacuum distillation, the operating pressure is 0.0001~0.03MPa, and the reflux ratio is (10~55):1.

[0024] Furthermore, in the above step (6), the extractive distillation tower adopts vacuum distillation, the operating pressure is 0.0001~0.02MPa, the reflux ratio is (5~35):1; the extractant is [THTDP]BF4 (trihexyl (tetradecyl) phosphine tetrafluoroborate), [TBMP]C9H 19 COO (tributyl (methyl)phosphine decanoate) or [TBHP]C9H 19 COO (tributyl (hexyl) phosphine decanoate), supplement every 60~100 hours.

[0025] The further beneficial effect of adopting the above method is that the extractant selected by the present invention can efficiently separate m-cresol and p-cresol. Specifically, the extraction selectivity of quaternary phosphonium ionic liquids for phenols is related to the cation of the quaternary phosphonium ionic liquids, and is ranked as follows: [THTDP]>[TBMP]>[TMTDP]>[TBHP]. The selectivity for the three cresols is ranked as follows: m-cresol>p-cresol>o-cresol, and [THTDP]BF4 has the highest selectivity for the three cresols.

[0026] Furthermore, in the above step (7), the p-cresol fraction tower adopts vacuum distillation, the operating pressure is 0.0001~0.025MPa, and the reflux ratio is (15~55):1.

[0027] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] Compared with the traditional continuous distillation process, the present invention uses vacuum distillation to separate the components, and the obtained product separation degree is higher, and the number of theoretical plates and energy consumption are less, thereby realizing the production of high-purity phenol products with low energy consumption, low cost and high efficiency, greatly improving economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 This is a schematic diagram of the structure of a continuous refining device for crude phenol.

[0031] Among them, 1-crude phenol storage tank, 2-dehydration tower, 3-primary distillation tower, 4-phenol fractionation tower, 5-o-cresol fractionation tower, 6-m-p-cresol tower, 7-extraction distillation tower, 8-p-cresol fractionation tower. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] Example 1

[0038] The continuous refining device of crude phenol comprises a crude phenol storage tank 1, a dehydration tower 2, a primary distillation tower 3, a phenol fraction tower 4, an o-cresol fraction tower 5, an m-cresol tower 6, an extractive distillation tower 7 and a p-cresol fraction tower 8 which are connected in sequence, and the top of each tower is individually connected to a cooler, and each cooler is connected to a vacuum system.

[0039] Example 2

[0040] The continuous refining method of crude phenol (12,000 tons / year crude phenol refining project) adopts the continuous refining device of Example 1, and specifically comprises the following steps:

[0041] (1) The crude phenol in the crude phenol storage tank 1 is preheated and then transported to the dehydration tower 2. The top product is condensed in a cooler, part of which is refluxed to the dehydration tower 2, and the remaining part of the phenol water is discharged. The bottom product is transported to the primary distillation tower 3;

[0042] Among them, the dehydration tower 2 is provided with heat by heat transfer oil;

[0043] (2) The heavy fraction is discharged from the bottom of the primary distillation tower 3, and the top product is condensed in a cooler, part of which is refluxed to the primary distillation tower 3, and the rest is transported to the phenol fractionation tower 4;

[0044] Among them, the primary distillation tower 3 adopts vacuum distillation, the operating pressure is 0.01MPa, and the reflux ratio is 10:1;

[0045] (3) After the top product of the phenol fraction tower 4 is condensed in a cooler, part of it is refluxed to the phenol fraction tower 4, and the remaining part of phenol is discharged, and the bottom product is transported to the o-cresol fraction tower 5;

[0046] Among them, the phenol fraction tower 4 adopts vacuum distillation, the operating pressure is 0.02MPa, and the reflux ratio is 8:1;

[0047] (4) The top product of the o-cresol fraction tower 5 is condensed in a cooler, part of which is refluxed to the o-cresol fraction tower 5, and the remaining part of the o-cresol is discharged, and the bottom product is transported to the m-cresol tower 6;

[0048] Among them, the o-cresol fraction tower 5 adopts vacuum distillation, the operating pressure is 0.01MPa, and the reflux ratio is 20:1;

[0049] (5) The residual oil at the bottom of the meta-para-cresol tower 6 is discharged, and the top product is condensed in a cooler, part of which is refluxed to the meta-para-cresol tower 6, and the rest is transported to the extractive distillation tower 7;

[0050] Among them, the m-p-cresol tower 6 adopts vacuum distillation, the operating pressure is 0.01MPa, and the reflux ratio is 15:1;

[0051] (6) Adding the extractant [THTDP]BF4 to the top of the extractive distillation tower 7 for extractive distillation, replenishing the extractant every 100 hours, condensing the top product in a cooler, partially refluxes to the extractive distillation tower 7, and the remaining part discharges the m-cresol, and the bottom product is transported to the p-cresol fractionation tower 8;

[0052] Among them, the extractive distillation tower 7 adopts vacuum distillation, the operating pressure is 0.005MPa, and the reflux ratio is 20:1;

[0053] (7) After the top product of the p-cresol fraction tower 8 is condensed in a cooler, part of it is refluxed to the p-cresol fraction tower 8, and the remaining part is discharged as p-cresol. The extractant at the bottom of the tower is refluxed to the extractive distillation tower 7 for recycling.

[0054] The p-cresol fraction tower 8 adopts vacuum distillation, with an operating pressure of 0.003 MPa and a reflux ratio of 30:1.

[0055] Example 3

[0056] The continuous refining method of crude phenol (10,000 tons / year crude phenol refining project) adopts the continuous refining device of Example 1, and specifically comprises the following steps:

[0057] (1) The crude phenol in the crude phenol storage tank 1 is preheated and then transported to the dehydration tower 2. The top product is condensed in a cooler, part of which is refluxed to the dehydration tower 2, and the remaining part of the phenol water is discharged. The bottom product is transported to the primary distillation tower 3;

[0058] Among them, the dehydration tower 2 is provided with heat by heat transfer oil;

[0059] (2) The heavy fraction is discharged from the bottom of the primary distillation tower 3, and the top product is condensed in a cooler, part of which is refluxed to the primary distillation tower 3, and the rest is transported to the phenol fractionation tower 4;

[0060] Among them, the primary distillation tower 3 adopts vacuum distillation, the operating pressure is 0.008MPa, and the reflux ratio is 18:1;

[0061] (3) After the top product of the phenol fraction tower 4 is condensed in a cooler, part of it is refluxed to the phenol fraction tower 4, and the remaining part of phenol is discharged, and the bottom product is transported to the o-cresol fraction tower 5;

[0062] Among them, the phenol fraction tower 4 adopts vacuum distillation, the operating pressure is 0.005MPa, and the reflux ratio is 12:1;

[0063] (4) The top product of the o-cresol fraction tower 5 is condensed in a cooler, part of which is refluxed to the o-cresol fraction tower 5, and the remaining part of the o-cresol is discharged, and the bottom product is transported to the m-cresol tower 6;

[0064] Among them, the o-cresol fraction tower 5 adopts vacuum distillation, the operating pressure is 0.008MPa, and the reflux ratio is 23:1;

[0065] (5) The residual oil at the bottom of the meta-para-cresol tower 6 is discharged, and the top product is condensed in a cooler, part of which is refluxed to the meta-para-cresol tower 6, and the rest is transported to the extractive distillation tower 7;

[0066] Among them, the m-cresol tower 6 adopts vacuum distillation, the operating pressure is 0.006MPa, and the reflux ratio is 51:1;

[0067] (6) Add the extractant [TBMP]C9H to the top of the extractive distillation tower 7 19 COO is subjected to extractive distillation, and the extractant is replenished every 90 hours. After the top product is condensed by the cooler, part of it is refluxed to the extractive distillation tower 7, and the remaining part is discharged from the m-cresol, and the bottom product is transported to the p-cresol fraction tower 8;

[0068] Among them, the extractive distillation tower 7 adopts vacuum distillation, the operating pressure is 0.002MPa, and the reflux ratio is 20:1;

[0069] (7) After the top product of the p-cresol fraction tower 8 is condensed in a cooler, part of it is refluxed to the p-cresol fraction tower 8, and the remaining part is discharged as p-cresol. The extractant at the bottom of the tower is refluxed to the extractive distillation tower 7 for recycling.

[0070] Among them, the p-cresol fraction tower 8 adopts vacuum distillation, the operating pressure is 0.007MPa, and the reflux ratio is 25:1.

[0071] Example 4

[0072] The continuous refining method of crude phenol (0.8 million tons / year crude phenol refining project) adopts the continuous refining device of Example 1, and specifically comprises the following steps:

[0073] (1) The crude phenol in the crude phenol storage tank 1 is preheated and then transported to the dehydration tower 2. The top product is condensed in a cooler, part of which is refluxed to the dehydration tower 2, and the remaining part of the phenol water is discharged. The bottom product is transported to the primary distillation tower 3;

[0074] Among them, the dehydration tower 2 is provided with heat by heat transfer oil;

[0075] (2) The heavy fraction is discharged from the bottom of the primary distillation tower 3, and the top product is condensed in a cooler, part of which is refluxed to the primary distillation tower 3, and the rest is transported to the phenol fractionation tower 4;

[0076] Among them, the primary distillation tower 3 adopts vacuum distillation, the operating pressure is 0.008MPa, and the reflux ratio is 21:1;

[0077] (3) After the top product of the phenol fraction tower 4 is condensed in a cooler, part of it is refluxed to the phenol fraction tower 4, and the remaining part of phenol is discharged, and the bottom product is transported to the o-cresol fraction tower 5;

[0078] Among them, the phenol fraction tower 4 adopts vacuum distillation, the operating pressure is 0.009MPa, and the reflux ratio is 10:1;

[0079] (4) The top product of the o-cresol fraction tower 5 is condensed in a cooler, part of which is refluxed to the o-cresol fraction tower 5, and the remaining part of the o-cresol is discharged, and the bottom product is transported to the m-cresol tower 6;

[0080] Among them, the o-cresol fraction tower 5 adopts vacuum distillation, the operating pressure is 0.008MPa, and the reflux ratio is 21:1;

[0081] (5) The residual oil at the bottom of the meta-para-cresol tower 6 is discharged, and the top product is condensed in a cooler, part of which is refluxed to the meta-para-cresol tower 6, and the rest is transported to the extractive distillation tower 7;

[0082] Among them, the m-cresol tower 6 adopts vacuum distillation, the operating pressure is 0.005MPa, and the reflux ratio is 25:1;

[0083] (6) Add the extractant [TBHP]C9H to the top of the extractive distillation tower 7 19 COO is subjected to extractive distillation, and the extractant is replenished every 60 hours. After the top product is condensed by the cooler, part of it is refluxed to the extractive distillation tower 7, and the remaining part is discharged from the m-cresol, and the bottom product is transported to the p-cresol fraction tower 8;

[0084] Among them, the extractive distillation tower 7 adopts vacuum distillation, the operating pressure is 0.005MPa, and the reflux ratio is 31:1;

[0085] (7) After the top product of the p-cresol fraction tower 8 is condensed in a cooler, part of it is refluxed to the p-cresol fraction tower 8, and the remaining part is discharged as p-cresol. The extractant at the bottom of the tower is refluxed to the extractive distillation tower 7 for recycling.

[0086] Among them, the p-cresol fraction tower 8 adopts vacuum distillation, the operating pressure is 0.008MPa, and the reflux ratio is 22:1.

[0087] Comparative Example

[0088] The conventional continuous distillation process of crude phenol, referring to the content of "Background Technology", specifically includes the following steps:

[0089] (1) Dehydrating and removing residue from crude phenol;

[0090] (2) It enters the phenol tower, o-cresol tower and m-cresol tower in sequence, and obtains phenol, o-cresol and m-cresol at the top of the tower in sequence.

[0091] Performance Testing

[0092] The crude phenol product obtained as a by-product in a certain petroleum production process was divided into 4 parts, and continuous distillation was performed according to the methods of the comparative example and Examples 2-4, and the purity of each separated product was measured respectively.

[0093] The results are shown in Table 1.

[0094] Table 1 Purity of each isolated product of Comparative Example and Examples 2-4

[0095] Separation products Comparative Example Example 2 Example 3 Example 4 phenol / % 99.0 99.1 99.0 99.0 o-Cresol / % 99.0 99.0 99.0 99.0 m-P-cresol mixture / % 82.0 97.3 97.3 97.3 Meta-cresol / % / 99.2 99.1 99.1 p-Cresol / % / 99.0 99.0 99.3

[0096] It can be seen from Table 1 that, compared with the comparative example, the products obtained in Examples 2-4 have higher purity, better separation effect, and higher economic value.

[0097] The above experiments show that the present invention greatly reduces the production cost after improving the existing process. Since crude phenol is a byproduct produced in large quantities during the production of coal-to-natural gas, and each phenolic component product has high added value, this project can bring considerable profits to the enterprise.

[0098] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0099] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A continuous refining method for crude phenol, characterized in that: The specific steps include: (1) The crude phenol in the crude phenol storage tank is preheated and then transported to the dehydration tower. The top product is condensed in a cooler, part of which is refluxed to the dehydration tower, and the remaining part is discharged as phenol water. The bottom product is transported to the primary distillation tower; The dehydration tower is provided with heat by heat-conducting oil; (2) The heavy fraction is discharged from the bottom of the primary distillation tower, and the top product is condensed in a cooler, part of which is refluxed to the primary distillation tower, and the rest is transported to the phenol fractionation tower; The primary distillation tower adopts vacuum distillation, the operating pressure is 0.0001~0.05MPa, and the reflux ratio is (5~30):1; (3) After the top product of the phenol fraction tower is condensed in a cooler, part of it is refluxed to the phenol fraction tower, and the remaining part is discharged as phenol. The bottom product is transported to the o-cresol fraction tower; The phenol fractionation tower adopts vacuum distillation, the operating pressure is 0.0001-0.08 MPa, and the reflux ratio is (4-25):1; (4) The top product of the o-cresol fraction tower is condensed in a cooler, part of which is refluxed to the o-cresol fraction tower, and the remaining o-cresol is discharged, and the bottom product is transported to the m-cresol tower; The o-cresol fractionation tower adopts vacuum distillation, the operating pressure is 0.0001-0.03 MPa, and the reflux ratio is (8-50):1; (5) The residual oil at the bottom of the meta-cresol tower is discharged, and the top product is condensed in a cooler, part of which is refluxed to the meta-cresol tower, and the rest is transported to the extractive distillation tower; The m-p-cresol tower adopts vacuum distillation, the operating pressure is 0.0001~0.03MPa, and the reflux ratio is (10~55):1; (6) adding an extractant to the top of the extractive distillation tower for extractive distillation, condensing the top product in a cooler, partially refluxing to the extractive distillation tower, discharging the remaining m-cresol, and conveying the bottom product to a p-cresol fractionation tower; In step (6), the extractive distillation tower adopts vacuum distillation, the operating pressure is 0.0001-0.02 MPa, and the reflux ratio is (5-35):1; the extractant is trihexyl (tetradecyl) phosphine tetrafluoroborate, tributyl (methyl) phosphine decanoate or tributyl (hexyl) phosphine decanoate, which is replenished every 60-100 hours; (7) After the top product of the p-cresol fraction tower is condensed in a cooler, part of it is refluxed to the p-cresol fraction tower, and the remaining part of the p-cresol is discharged. The extractant at the bottom of the tower is refluxed to the extraction distillation tower for recycling; The p-cresol fraction tower adopts vacuum distillation, the operating pressure is 0.0001~0.025MPa, and the reflux ratio is (15~55):1.

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