Tar dehydrating tower structure

Abstract

The utility model relates to the technical field of tar treatment, in particular to a tar dehydrating tower structure. In order to solve the problems in the prior art that the cost is higher, the occupied space is larger and the pressure and the temperature of the tower top are easy to fluctuate when separated light oil is conveyed to the tower top by adopting a light oil pump to control the temperature and the pressure of the tower top, the utility model provides a novel tar dehydrating tower structure. Comprising a dehydrating tower, a tar conveying pipeline, an anhydrous tar recovery pipeline, an anhydrous tar circulating pipeline, an anhydrous tar heat exchanger, an oil-gas mixture pipeline, a condenser and an oil-water separator. According to the utility model, the detection instrument is arranged on the pipeline, and the water content and the light oil quantity in the tar serve as the tar treatment capacity of the dehydrating tower, so that the pressure at the top of the tower is ensured to be constant; the water-free tar circulating pipeline is arranged, heat energy needed by the dehydrating tower is derived according to the water content and the light oil amount of tar, temperature control is conducted, and therefore the product quality is stable, the structure is simple, cost is low, and occupied space is small.

Description

Technical Field

[0001] This utility model relates to the field of tar treatment technology, and particularly to the field of tar dehydration technology, specifically a tar dehydration tower structure. Background Technology

[0002] In the tar processing flow, the first step in the tar treatment process is to dehydrate the tar by using a dehydration tower, taking advantage of the physical property that water has a low vaporization temperature, to obtain anhydrous tar.

[0003] Since tar contains light oil components, its vaporization point is around 100℃, which is close to the vaporization temperature of water (100℃). Therefore, when the temperature is controlled at 100℃, light oil and water are vaporized and separated from the tar by the dehydration tower. The separated oil-gas mixture (hereinafter, the oil-gas mixture refers to light oil and water) is cooled by a heat exchanger to form an oil-water mixture. The oil-water mixture is then separated by an oil-water separator using the incompatibility of the medium to obtain water and light oil.

[0004] To ensure the purity of the separation between light oil and anhydrous tar, the temperature of the dehydration tower must be controlled. Excessive temperature can cause the heavy component oil to vaporize, allowing it to enter the light oil and affect its quality. Conversely, excessively low temperatures can lead to incomplete tar dehydration, affecting the quality of the anhydrous tar. Simultaneously, the liquid level in the dehydration tower must be controlled; excessively high levels can affect the tower trays and reduce efficiency. Furthermore, the pressure in the dehydration tower must be controlled, maintaining a slightly positive pressure at the top. Excessively high pressure can cause… The dehydration tower is subjected to steam pressure explosion. If the pressure is too low, it will lower the evaporation temperature of heavy components, resulting in the presence of heavy components in the light oil and affecting the quality of the light oil. The water content in the tar has a significant impact on the pressure at the top of the dehydration tower. Since the specific heat capacity of water is 4.3 J / (g×℃) and that of tar is 0.9-1.5 J / (g×℃), excessive water content will lower the overall tower temperature under the condition that the heat exchange of anhydrous tar remains unchanged, affecting the evaporation of light oil. The evaporation of a large amount of water will lead to an increase in the pressure at the top of the tower.

[0005] To ensure the pressure and temperature at the top of the tower, the existing technology uses a light oil pump to transport the separated light oil to the top of the tower for control of the temperature and pressure. However, this method requires additional equipment and pipelines, which is costly and takes up a lot of space. At the same time, the circulation of light oil can easily cause fluctuations in the pressure and temperature at the top of the tower, thus affecting product quality. Summary of the Invention

[0006] To address the problems of high cost, large space occupation, and easy fluctuations in pressure and temperature at the top of the tower caused by using a light oil pump to transport the separated light oil to the top of the tower for control of the tower top temperature and pressure, this utility model provides a new tar dehydration tower structure.

[0007] This utility model is achieved using the following technical solution:

[0008] A tar dehydration tower structure includes a dehydration tower, a tar conveying pipeline, an anhydrous tar extraction pipeline, an anhydrous tar circulation pipeline, an anhydrous tar heat exchanger, an oil-gas mixture pipeline, a condenser, and an oil-water separator. The dehydration tower is equipped with a bottom level gauge, a bottom resistance temperature detector (RTD), a top pressure transmitter, and a top RTD. The tar conveying pipeline is equipped with a tar conveying pump, a tar flow meter, an RTD, a moisture analyzer, and a tar density meter. The tar conveying pipeline is connected to the tar inlet of the dehydration tower. The anhydrous tar extraction pipeline is equipped with an anhydrous tar extraction pump. The anhydrous tar circulation pipeline is equipped with an anhydrous tar circulation pump and an anhydrous tar circulation flow meter. One end of the anhydrous tar circulation pipeline is connected to the bottom of the dehydration tower. The anhydrous tar circulation outlet is connected to the anhydrous tar circulation pipeline, and the other end of the anhydrous tar circulation pipeline is connected to the cold source inlet of the anhydrous tar heat exchanger. The cold source outlet of the anhydrous tar heat exchanger is connected to the anhydrous tar circulation inlet of the dehydration tower through the heat exchange pipeline. A bypass pipeline is provided between the anhydrous tar circulation pipeline and the heat exchange pipeline. A high-temperature anhydrous tar thermal resistor is provided on the heat exchange pipeline. A bypass valve is also provided on the bypass pipeline. One end of the oil-gas mixture pipeline is connected to the gas outlet at the top of the tower. The other end of the oil-gas mixture pipeline is connected to the inlet of the condenser. The outlet of the condenser is connected to the inlet of the oil-water separator. The oil-water outlet of the oil-water separator is connected to the light oil storage tank. The water outlet of the oil-water separator is connected to the deoiled water storage tank.

[0009] Principle Explanation: A. Control Logic Mechanism for Pre-Constant Tower Top Pressure:

[0010] Temperature determines the quality of the product evaporated from the dehydration tower. Under the condition of ensuring product quality, since the volume at the top of the tower is constant, the water content and light oil content in the tar are the only factors affecting the top pressure. Using the water and light oil content in the tar as indicators of the dehydration tower's processing capacity, the tar inlet flow rate, as well as the water and light oil inlets, are pre-set to ensure constant evaporation rate and pressure. Since the water and light oil content fed into the dehydration tower system is constant, assuming a constant tower temperature, the distillation rates of water and light oil within the tower will be constant, thus ensuring a constant top pressure.

[0011] 1) The density of tar is measured by a tar density meter (ρ). 焦油， The moisture content of tar was determined by a moisture analyzer. 水， Set the density value ρ of qualified light oil 轻油 Qualified anhydrous tar density value ρ 无水焦油 The density value of water ρ 水 Given a quantity, the light oil content K in the tar. 轻油 The content of anhydrous tar (K) in tar 无水油 Since the content of is unknown, the following formula is derived:

[0012] Formula 1: ρ 焦油 =K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +K 无水焦油 ×ρ 无水油

[0013] Formula 2: K 水 +K 轻油 +K 无水焦油 =1

[0014] Substituting Formula 1 into Formula 2, we get:

[0015] Formula 3: ρ 焦油 =K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +K 无水焦油 ×ρ 无水油 = K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +(1- K 水 -K 轻油 )×ρ 无水焦油 = K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +ρ 无水焦油 - K 水 ×ρ 无水焦油- K 轻油 ×ρ 无水焦油 = K 水 ×ρ 水 - K 水 ×ρ 无水焦油 + K 轻油 ×(ρ 轻油 -ρ 无水焦油 )+ρ 无水焦油

[0016] From Formula 3, we can derive

[0017] K 轻油 =(ρ 焦油 - K 水 ×ρ 水 + K 水 ×ρ 无水焦油 -ρ 无水焦油 ) / (ρ 轻油 -ρ 无水焦油 )

[0018] K 无水油 =1- K 水 -(ρ 焦油- K 水 ×ρ 水 + K 水 ×ρ 无水焦油 -ρ 无水焦油 ) / (ρ 轻油 -ρ 无水焦油 )

[0019] 2) The design pressure at the top of the dehydration tower is P (determined by the exhaust gas from the dehydration tower).

[0020] P×V / T=N×R

[0021] Where: V is the meteorological space volume;

[0022] T is the water evaporation temperature, which is measured by the thermal resistance at the top of the tower;

[0023] N is the number of moles of water and light oil components in the tar, taken as the average of the samples;

[0024] R is the universal gas constant;

[0025] Then P×V / T=(K 水 ×Q 焦油 / m 水 +K 轻油 ×Q 焦油 / m 轻油 )×R

[0026] Among them: Q 焦油 The tar flow rate into the dehydration tower is measured by a tar flow meter;

[0027] m 水 The molar mass of water;

[0028] m 轻油 The molar mass of light oil;

[0029] Then Q 焦油 =P×V / (T×R) / (K 水 / m 水 +K 轻油 / m 轻油 )

[0030] As shown above, the tar inlet flow rate can be determined by the tower top temperature T, tower top pressure P, and tar moisture content K. 水、 Tar density ρ 焦油 Light oil density ρ 轻油 water density ρ 水 Anhydrous tar density ρ 无水焦油 The parameters were jointly determined, including the top temperature T, top pressure P, and moisture content K in the tar. 水、 Tar density ρ 焦油 Anhydrous tar density ρ 无水焦油The flow rate can be detected in real time or is known through detection elements. By setting the flow rate regulation logic between the tar delivery pump and the tar inlet flow rate in the dehydration tower according to the above relationship, the amount of water and light oil entering the dehydration tower can be kept constant, thereby achieving stable pressure at the top of the tower.

[0031] B. Dehydration tower liquid level constant control logic mechanism:

[0032] Set the dehydration tower liquid level according to the design value, and set the liquid level regulation logic between the anhydrous tar extraction pump and the dehydration tower liquid level to achieve stable dehydration tower liquid level.

[0033] C. Dehydration tower temperature pre-constant control logic mechanism:

[0034] According to the law of conservation of energy, by analyzing the composition ratio of the tar entering the dehydration tower, the required heat energy is supplied in advance to keep the temperature of the dehydration tower constant. With the anhydrous tar circulation rate set as a constant, the actual temperature of the anhydrous tar after heat exchange is adjusted by the heat exchanger bypass regulating valve; the setpoint temperature of the anhydrous tar after heat exchange is calculated from the heat energy required by the dehydration tower system.

[0035] The heat energy required for the tar entering the dehydration tower to heat up is:

[0036] W 焦油升温 =(K 无水焦油 ×Q 焦油 ×△C 无水焦油 )×(T1-T2)+K 轻油 ×Q 焦油 ×△C 轻油 ×(T4-T2)+(K 水 ×Q 焦油 ×△C 水 ) × (T4-T2);

[0037] W 设备散热 =A 脱水塔 ×[9.4+0.052×(T1-T0)]×(T1-T0);

[0038] W 无水焦油循环热能 =W 焦油升温 +W 设备散热 =Q 循环无水焦油 ×△C 无水焦油 ×(T3-T1)

[0039] Among them: A 脱水塔 Let ΔC be the volume of the dehydration tower. 无水焦油 The specific heat capacity of anhydrous tar is ΔC. 轻油 For the specific heat capacity of light oil, ΔC 水T1 is the specific heat capacity of water, T2 is the ambient temperature, T3 is the temperature measured by the thermal resistor at the bottom of the tower, T4 is the temperature measured by the thermal resistor of the tar, T5 is the temperature measured by the thermal resistor of the high-temperature anhydrous tar, and T6 is the temperature measured by the thermal resistor at the top of the tower.

[0040] T3 setting value = [(W 焦油升温 +W 设备散热 ) / (Q 循环无水焦油 ×△C 无水焦油 )]+ T1={[(K 无水焦油 ×Q 焦油 ×△C 无水焦油 )×(T1-T2)+K 轻油 ×Q 焦油 ×△C 轻油 ×(T4-T2)+(K 水 ×Q 焦油 ×△C 水 )×(T4-T2)+ A 脱水塔 ×[9.4+0.052×(T1-T0)]×(T1-T0)] / (Q 循环无水焦油 ×△C 无水焦油 )}+T1

[0041] The beneficial effects of this utility model are as follows: By setting up a detection instrument on the pipeline, and then using the water content and light oil content in the tar as the tar processing capacity of the dehydration tower, the pressure at the top of the tower is kept constant; by setting up an anhydrous tar circulation pipeline, the required heat energy of the dehydration tower is derived from the water content and light oil content of the tar, and used as the calorific value of the anhydrous tar circulation, the heat energy entering the tower is controlled in advance, and the temperature is controlled, resulting in stable product quality, simple structure, low cost and small space occupation. Attached Figure Description

[0042] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0043] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0045] In the diagram: 1-Dehydration tower, 2-Anhydrous tar heat exchanger, 3-Condenser, 4-Oil-water separator, 5-Bottom level gauge, 6-Bottom resistance temperature detector, 7-Top pressure transmitter, 8-Top resistance temperature detector, 9-Tar transfer pump, 10-Tar flow meter, 11-Tar resistance temperature detector, 12-Moisture analyzer, 13-Tar density meter, 14-Anhydrous tar extraction pump, 15-Anhydrous tar circulation pump, 16-Anhydrous tar circulation flow meter, 17-Bypass valve, 18-Light oil storage tank, 19-Dehydrated water storage tank, 20-High temperature anhydrous tar resistance temperature detector. Detailed Implementation

[0046] To better understand the above-mentioned objectives, features, and advantages of this utility model, the solution of this utility model will be further described below. It should be noted that, unless otherwise specified, the embodiments of this utility model and the features thereof can be combined with each other.

[0047] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the present invention, and not all embodiments.

[0049] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0050] like Figure 1As shown, a tar dehydration tower structure includes a dehydration tower 1, a tar conveying pipeline, an anhydrous tar extraction pipeline, an anhydrous tar circulation pipeline, an anhydrous tar heat exchanger 2, an oil-gas mixture pipeline, a condenser 3, and an oil-water separator 4. The dehydration tower 1 is equipped with a bottom level gauge 5, a bottom thermal resistor 6, a top pressure transmitter 7, and a top thermal resistor 8. The tar conveying pipeline is equipped with a tar conveying pump 9, a tar flow meter 10, a tar thermal resistor 11, a moisture analyzer 12, and a tar density meter 13. The tar conveying pipeline is connected to the tar inlet of the dehydration tower 1. The anhydrous tar extraction pipeline is equipped with an anhydrous tar extraction pump 14. The anhydrous tar circulation pipeline is equipped with an anhydrous tar circulation pump 15 and an anhydrous tar circulation flow meter 16. One end of the anhydrous tar circulation pipeline is connected to the dehydration tower 1. The bottom of water tower 1 is connected to the anhydrous tar circulation outlet, and the other end of the anhydrous tar circulation pipeline is connected to the cold source inlet of anhydrous tar heat exchanger 2. The cold source outlet of anhydrous tar heat exchanger 2 is connected to the anhydrous tar circulation inlet of dehydration tower 1 through a heat exchange pipeline. A bypass pipeline is provided between the anhydrous tar circulation pipeline and the heat exchange pipeline. A high-temperature anhydrous tar resistance thermometer 20 is provided on the heat exchange pipeline. A bypass valve 17 is also provided on the bypass pipeline. One end of the oil-gas mixture pipeline is connected to the gas outlet at the top of the tower, and the other end of the oil-gas mixture pipeline is connected to the inlet of condenser 3. The outlet of condenser 3 is connected to the inlet of oil-water separator 4. The oil-water outlet of oil-water separator 4 is connected to light oil storage tank 18, and the water outlet of oil-water separator 4 is connected to de-oiled water storage tank 19.

[0051] Principle Explanation: A. Control Logic Mechanism for Pre-Constant Tower Top Pressure:

[0052] Temperature determines the quality of the product evaporated from dehydration tower 1. Under the condition of ensuring the product quality of dehydration tower 1, since the volume at the top of the tower is constant, the water content and light oil content in the tar are the only factors affecting the top pressure. Using the water content and light oil content in the tar as indicators of the processing capacity of dehydration tower 1, the tar inlet flow rate, as well as the water and light oil inlets into dehydration tower 1, are pre-set to ensure a constant evaporation rate and constant pressure in dehydration tower 1. Since the water and light oil content fed into the system of dehydration tower 1 is constant, assuming a constant temperature in dehydration tower 1, the distillation rate of water and light oil within dehydration tower 1 will be constant, thus ensuring a constant top pressure.

[0053] 1) The density of the tar was measured by a tar density meter 13. 焦油， The moisture content of the tar was determined by a moisture analyzer 12K. 水， Set the density value ρ of qualified light oil 轻油 Qualified anhydrous tar density value ρ 无水焦油 The density value of water ρ 水 Given a quantity, the light oil content K in the tar. 轻油 The content of anhydrous tar (K) in tar 无水油 Since the content of is unknown, the following formula is derived:

[0054] Formula 1: ρ 焦油 =K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +K 无水焦油 ×ρ 无水油

[0055] Formula 2: K 水 +K 轻油 +K 无水焦油 =1

[0056] Substituting Formula 1 into Formula 2, we get:

[0057] Formula 3: ρ 焦油 =K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +K 无水焦油 ×ρ 无水油 = K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +(1- K 水 -K 轻油 )×ρ 无水焦油 = K 水 ×ρ 水 +K 轻油 ×ρ 轻油 +ρ 无水焦油 - K 水 ×ρ 无水焦油- K 轻油 ×ρ 无水焦油 = K 水 ×ρ 水 - K 水 ×ρ 无水焦油 + K 轻油 ×(ρ 轻油 -ρ 无水焦油 )+ρ 无水焦油

[0058] From Formula 3, we can derive

[0059] K 轻油 =(ρ 焦油 - K 水 ×ρ 水 + K 水 ×ρ 无水焦油 -ρ 无水焦油 ) / (ρ 轻油 -ρ 无水焦油 )

[0060] K 无水油 =1- K 水 -(ρ焦油 - K 水 ×ρ 水 + K 水 ×ρ 无水焦油 -ρ 无水焦油 ) / (ρ 轻油 -ρ 无水焦油 )

[0061] 2) The design pressure at the top of dehydration tower 1 is P (determined by the exhaust gas from dehydration tower 1).

[0062] P×V / T=N×R

[0063] Where: V is the meteorological space volume;

[0064] T is the water evaporation temperature, which is measured by the thermal resistance 8 at the top of the tower;

[0065] N is the number of moles of water and light oil components in the tar, taken as the average of the samples;

[0066] R is the universal gas constant;

[0067] Then P×V / T=(K 水 ×Q 焦油 / m 水 +K 轻油 ×Q 焦油 / m 轻油 )×R

[0068] Among them: Q 焦油 The flow rate of tar entering dehydration tower 1 is measured by tar flow meter 10;

[0069] m 水 The molar mass of water;

[0070] m 轻油 The molar mass of light oil;

[0071] Then Q 焦油 =P×V / (T×R) / (K 水 / m 水 +K 轻油 / m 轻油 )

[0072] As shown above, the tar inlet flow rate can be determined by the tower top temperature T, tower top pressure P, and tar moisture content K. 水、 Tar density ρ 焦油 Light oil density ρ 轻油 water density ρ 水 Anhydrous tar density ρ 无水焦油 The parameters were jointly determined, including the top temperature T, top pressure P, and moisture content K in the tar. 水、 Tar density ρ 焦油 Anhydrous tar density ρ无水焦油 The flow rate can be detected in real time or is known through a detection element. The flow rate of the tar delivery pump 9 and the flow rate of the tar entering the dehydration tower 1 are set according to the above relationship to achieve a stable flow rate of water and light oil entering the dehydration tower 1, that is, to achieve a stable pressure at the top of the tower.

[0073] B. Control logic mechanism for constant liquid level in dehydration tower 1:

[0074] Set the liquid level of dehydration tower 1 according to the design value of dehydration tower 1, and set the liquid level regulation logic of anhydrous tar extraction pump 14 and dehydration tower 1 to achieve stable liquid level of dehydration tower 1.

[0075] C. Control logic mechanism for pre-constant temperature of dehydration tower 1:

[0076] According to the law of conservation of energy, by analyzing the composition ratio of the tar entering dehydration tower 1, the required heat energy is supplied in advance to keep the temperature of dehydration tower 1 constant. The anhydrous tar circulation rate is set to a constant value, and the actual temperature of the anhydrous tar after heat exchange is adjusted by the heat exchanger bypass regulating valve; the set value of the anhydrous tar temperature after heat exchange is calculated from the heat energy required by the dehydration tower 1 system.

[0077] The heat energy required for the tar entering the dehydration tower to heat up is:

[0078] W 焦油升温 =(K 无水焦油 ×Q 焦油 ×△C 无水焦油 )×(T1-T2)+K 轻油 ×Q 焦油 ×△C 轻油 ×(T4-T2)+(K 水 ×Q 焦油 ×△C 水 ) × (T4-T2);

[0079] W 设备散热 =A 脱水塔1 ×[9.4+0.052×(T1-T0)]×(T1-T0);

[0080] W 无水焦油循环热能 =W 焦油升温 +W 设备散热 =Q 循环无水焦油 ×△C 无水焦油 ×(T3-T1)

[0081] Among them: A 脱水塔1 Let C be the volume of dehydration tower 1. 无水焦油 The specific heat capacity of anhydrous tar is ΔC. 轻油 For the specific heat capacity of light oil, ΔC 水T1 is the specific heat capacity of water, T2 is the ambient temperature, T3 is the temperature measured by the bottom resistance temperature detector (RTD 6), T4 is the temperature measured by the tar resistance temperature detector (RTD 11), T5 is the temperature measured by the high-temperature anhydrous tar resistance temperature detector (RTD 20), and T6 is the temperature measured by the top resistance temperature detector (RTD 8).

[0082] T3 setting value = [(W 焦油升温 +W 设备散热 ) / (Q 循环无水焦油 ×△C 无水焦油 )]+ T1={[(K 无水焦油 ×Q 焦油 ×△C 无水焦油 )×(T1-T2)+K 轻油 ×Q 焦油 ×△C 轻油 ×(T4-T2)+(K 水 ×Q 焦油 ×△C 水 )×(T4-T2)+ A 脱水塔 ×[9.4+0.052×(T1-T0)]×(T1-T0)] / (Q 循环无水焦油 ×△C 无水焦油 )}+T1.

[0083] The above description is merely a specific embodiment of this utility model, enabling those skilled in the art to understand or implement it. Although detailed descriptions have been provided 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and all should be covered by the protection scope of the claims.

Claims

1. A tar dehydration column structure, characterized by, The device comprises a dehydration tower (1), a tar conveying pipeline, a waterless tar production pipeline, a waterless tar circulation pipeline, a waterless tar heat exchanger (2), an oil-gas mixture pipeline, a condenser (3), and an oil-water separator (4). The dehydration tower (1) is provided with a tower bottom liquid level meter (5), a tower bottom thermal resistance (6), a tower top pressure transmitter (7), and a tower top thermal resistance (8). The tar conveying pipeline is provided with a tar conveying pump (9), a tar flow meter (10), a tar thermal resistance (11), a water content detector (12), and a tar density meter (13). The tar conveying pipeline is communicated with the tar inlet of the dehydration tower (1). The waterless tar production pipeline is provided with a waterless tar production pump (14). The waterless tar circulation pipeline is provided with a waterless tar circulation pump (15) and a waterless tar circulation flow meter (16). One end of the waterless tar circulation pipeline is communicated with the waterless tar circulation outlet at the bottom of the dehydration tower (1). The other end of the waterless tar circulation pipeline is communicated with the cold source inlet of the waterless tar heat exchanger (2). The cold source outlet of the waterless tar heat exchanger (2) is communicated with the waterless tar circulation inlet of the dehydration tower (1) through a heat exchange pipeline. A bypass pipeline is arranged between the waterless tar circulation pipeline and the heat exchange pipeline. A high-temperature waterless tar thermal resistance (20) is arranged on the heat exchange pipeline. A bypass valve (17) is further arranged on the bypass pipeline. One end of the oil-gas mixture pipeline is communicated with the tower top gas outlet. The other end of the oil-gas mixture pipeline is communicated with the inlet of the condenser (3). The outlet of the condenser (3) is connected with the inlet of the oil-water separator (4). The oil-water outlet of the oil-water separator (4) is communicated with a light oil storage tank (18). The water outlet of the oil-water separator (4) is communicated with a deoiled water storage tank (19).

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