Heat exchanger for crude benzene processing to avoid leakage of lean oil and rich oil

Abstract

The present invention relates to the field of heat exchangers, and specifically to a crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil. The heat exchanger comprises a heat exchange bin body formed by two groups of parallel metal plates through a spiral, high-temperature and low-temperature feed ports and high-temperature and low-temperature discharge ports, and also comprises a flow monitoring unit, a heat exchange monitoring unit, a pressure monitoring unit and a control platform. In the present invention, by monitoring the pressure at the discharge point of the heat exchange bin body, and judging whether a follow-up phenomenon occurs in another group of spiral channels when the pressure changes, the leakage situation is judged, and at the same time, the leakage phenomenon is detected from another angle through the flow difference between the two groups of spiral channels, and the leakage phenomenon is further monitored by comparing the heat exchange coefficient with the set heat exchange coefficient, and the multi-angle monitoring is integrated through the control platform to improve the accuracy of the leakage monitoring.

Description

Technical Field

[0001] The invention relates to the field of heat exchangers, in particular to a crude benzene processing heat exchanger which can avoid leakage of lean oil and rich oil. Background Art

[0002] Coking enterprises have always been important manufacturers of benzene products. The main way to obtain benzene is to recycle crude benzene in coke oven gas. At present, the oil-oil heat exchangers used by most coking enterprises are three-dimensional plate heat exchangers with poor heat exchange effect. The temperature of rich oil cannot reach 80°C after heat exchange, and the heat exchanger body will leak in many places soon after being put into use, requiring frequent shutdowns for repair welding, which greatly reduces the commissioning efficiency of eluted benzene production and reduces the output of crude benzene. This kind of three-dimensional plate oil-oil heat exchanger still has a large gap between lean oil and rich oil. Rich oil will flow into lean oil under higher pressure, resulting in a weakening of the lean oil's absorption capacity, which ultimately leads to a reduction in crude benzene production.

[0003] In the prior art, there is a spiral plate heat exchanger made by bending parallel steel plates, which has better heat exchange performance than the traditional three-dimensional plate heat exchanger. However, since a large part of the heat exchange path of the spiral plate heat exchanger is surrounded by the spiral plate, it is difficult to detect when the spiral plate heat exchanger leaks, which easily causes the lean oil and rich oil flowing in the spiral plate heat exchanger to leak, resulting in the contamination of the lean oil and affecting the subsequent absorption effect of the lean oil.

[0004] In view of the above technical problems, this application proposes a solution. Summary of the invention

[0005] In the present invention, by monitoring the pressure at the discharge point of the heat exchange bin, the leakage is judged according to the follow-up phenomenon in the other group of spiral channels when the pressure changes, the leakage is detected from another angle through the flow difference between the two groups of spiral channels, and then the heat transfer coefficient is compared with the set heat transfer coefficient to achieve further monitoring of the leakage, so as to solve the problem that when the spiral plate heat exchanger is damaged inside and causes leakage of the two heat exchange liquids, it is very difficult to detect, and a crude benzene processing heat exchanger that avoids leakage of lean oil and rich oil is proposed.

[0006] The object of the present invention can be achieved by the following technical scheme: a crude benzene processing heat exchanger for preventing leakage of lean oil and rich oil comprises a heat exchange bin, the heat exchange bin is made of two sets of parallel metal plates through spirals, and two sets of spiral channels are formed in the heat exchange bin, and the two sets of spiral channels are respectively a high-temperature spiral channel and a low-temperature spiral channel;

[0007] A high-temperature feed inlet and a low-temperature feed inlet are installed at both ends of the heat exchange bin, and bin covers are installed on both upper and lower sides of the heat exchange bin. A low-temperature discharge port is installed on the upper bin cover, and a high-temperature discharge port is installed on the lower bin cover;

[0008] Also included is a crude benzene processing heat exchanger operation control system, including a flow monitoring unit, a heat exchange monitoring unit, a pressure monitoring unit and a control platform;

[0009] The flow monitoring unit is used to monitor and compare the liquid flow in the heat exchange chamber to determine whether there are abnormalities in the high-temperature channel and the low-temperature channel;

[0010] The heat exchange monitoring unit is used to obtain the heat exchange coefficient of the heat exchange bin, and generate a normal heat exchange signal or an abnormal heat exchange signal according to the heat exchange coefficient analysis;

[0011] The pressure monitoring unit is used to monitor the pressure at the outlet of the heat exchange chamber. When the pressure is abnormal, the pressure is adjusted and tested to confirm whether there is leakage.

[0012] As a preferred embodiment of the present invention, there is a discharge structure in the center of the heat exchange bin, and the discharge structure is divided into two groups on the left and the right. The low-temperature feed port is connected to the low-temperature discharge port through the discharge structure on the left, and the high-temperature feed port is connected to the high-temperature discharge port through the discharge structure on the right.

[0013] As a preferred embodiment of the present invention, the flow monitoring unit collects the liquid flow passing through the high-temperature feed port and records it in sections, respectively obtaining flow statistical data in multiple time periods of the same length, and the flow monitoring unit performs arithmetic averaging on the multiple flow statistical data to obtain the high-temperature feed mean value;

[0014] The flow monitoring unit collects the flow in the high-temperature discharge port, the low-temperature feed port and the low-temperature discharge port through liquid flow meters installed at the high-temperature discharge port, the low-temperature feed port and the low-temperature discharge port, and calculates the high-temperature discharge mean, the low-temperature feed mean and the low-temperature discharge mean.

[0015] As a preferred embodiment of the present invention, the flow monitoring unit compares the high-temperature feed average and the high-temperature discharge average to obtain a high-temperature fluid difference. If the high-temperature fluid difference is not within an allowable range, a high-temperature channel abnormal signal is generated;

[0016] The flow monitoring unit compares the low-temperature feed average with the low-temperature discharge average to obtain a low-temperature fluid difference. If the high-temperature fluid difference is not within an allowable range, a low-temperature channel abnormal signal is generated;

[0017] The flow monitoring unit generates a cross-talk alarm when generating any one of a high-temperature channel abnormal signal or a low-temperature channel abnormal signal.

[0018] As a preferred embodiment of the present invention, the heat exchange monitoring unit collects the temperatures in the high-temperature feed port, the high-temperature discharge port, the low-temperature feed port and the low-temperature discharge port, calculates according to the temperature difference between the high-temperature feed port and the high-temperature discharge port to obtain the high-temperature difference, and calculates according to the temperature difference between the low-temperature feed port and the low-temperature discharge port to obtain the low-temperature difference;

[0019] The heat exchange monitoring unit obtains the liquid flow rate in the high-temperature feed port and the low-temperature feed port and the length of the spiral path in the preset heat exchange bin, and calculates the time required for the liquid to pass through the heat exchange bin according to the length and flow rate of the spiral path to obtain the high-temperature flow time and the low-temperature flow time.

[0020] As a preferred embodiment of the present invention, the heat exchange monitoring unit calculates the heat exchange efficiency through a preset formula by using the high temperature difference, the low temperature difference, the high temperature flow time and the low temperature flow time;

[0021] The heat exchange monitoring unit compares the heat exchange coefficient with the set nominal heat exchange coefficient to generate a heat exchange abnormality signal or a heat exchange normal signal.

[0022] As a preferred embodiment of the present invention, the pressure monitoring unit records the liquid pressure at the high-temperature discharge port and the low-temperature discharge port as the high-temperature pressure and the low-temperature pressure, and the pressure monitoring unit calculates the variance of all the acquired high-temperature pressures and low-temperature pressures through a variance formula to obtain the high-temperature variance and the low-temperature variance;

[0023] The pressure monitoring unit compares the high temperature variance with a set threshold value, and generates a high temperature pressure fluctuation signal or a high temperature pressure stability signal according to the comparison result;

[0024] The pressure monitoring unit compares the low temperature variance with a set threshold value, and generates a low temperature pressure fluctuation signal or a low temperature pressure stability signal according to the comparison result.

[0025] As a preferred embodiment of the present invention, after generating the high-temperature pressure fluctuation signal, the pressure monitoring unit adjusts the pressure in the low-temperature spiral channel. If the high-temperature pressure shows a follow-up phenomenon when the pressure in the low-temperature spiral channel is reciprocated, a leakage signal is generated, wherein the follow-up phenomenon refers to that after the pressure in the low-temperature spiral channel decreases, the average value of the high-temperature pressure decreases, and after the pressure in the low-temperature spiral channel increases, the average value of the high-temperature pressure increases;

[0026] After the low-temperature pressure fluctuation signal is generated, the pressure in the high-temperature spiral channel is adjusted. If the low-temperature pressure shows a follow-up phenomenon, a leakage signal is generated.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. In the present invention, the pressure at the discharge point of the heat exchange bin is continuously monitored, and a preliminary judgment on the integrity of the liquid flow in the heat exchange bin is made based on the pressure fluctuation at the discharge point. When an abnormality occurs, the operating pressure of one group of spiral channels is changed, and the operating pressure of the other group of spiral channels is monitored by follow-up phenomenon to confirm whether there is leakage between the two groups of spiral channel brackets, thereby ensuring that faults occurring during the operation of the heat exchange bin can be discovered in time, thereby avoiding long-term operation of the faulty heat exchange bin.

[0029] 2. In the present invention, during the operation of the heat exchange bin, the flow rates of the two groups of spiral channels in the heat exchange bin are monitored, so as to determine whether there is leakage between the two groups of spiral channels according to the feeding speed and discharging speed of the two groups of spiral channels. In this way, the airtightness of the spiral channels is monitored without affecting the normal operation of the heat exchange bin, thereby ensuring the normal operation of the heat exchange bin.

[0030] 3. In the present invention, the heat exchange coefficient of the heat exchange bin is evaluated by the temperature sensor provided in the heat exchange bin. According to whether the heat exchange coefficient is consistent with the set heat exchange coefficient, it is further confirmed whether there is leakage in the heat exchange bin, thereby improving the ability to monitor the operation of the heat exchange bin. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0032] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0033] Figure 2 is a system block diagram of the present invention;

[0034] Figure 3 It is a schematic diagram of the top view of the structure of the present invention;

[0035] Figure 4 It is a side view structural schematic diagram of the present invention

[0036] Figure 5 It is a system flow chart of the present invention.

[0037] In the figure: 1. heat exchange bin; 2. bin cover; 3. high-temperature feed inlet; 4. low-temperature feed inlet; 5. discharge port; 51. low-temperature discharge port; 52. high-temperature discharge port. DETAILED DESCRIPTION

[0038] The technical scheme of the present invention will be described clearly and completely in conjunction with the embodiments below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1: Please refer to Figure 1 - Figure 5 As shown, a crude benzene processing heat exchanger for preventing leakage of lean oil and rich oil comprises a heat exchange bin 1, which is made of two sets of parallel metal plates through spirals, and two sets of spiral channels are formed in the heat exchange bin 1, and lean oil and rich oil are transported through the two sets of spiral channels respectively, and the two sets of spiral channels are respectively a high-temperature spiral channel and a low-temperature spiral channel;

[0040] When lean oil and rich oil flow in the two sets of spiral channels, heat is conducted through the spiral metal plates to complete the heat transfer exchange. A high-temperature feed port 3 and a low-temperature feed port 4 are respectively installed at both ends of the heat exchange bin 1, which are used to introduce lean oil and rich oil respectively;

[0041] The heat exchange bin body 1 is provided with bin body covers 2 on both the upper and lower sides. The upper bin body cover 2 is provided with a low-temperature discharge port 51, and the lower bin body cover 2 is provided with a high-temperature discharge port 52.

[0042] At the center of the heat exchange bin 1 is a discharge structure 5, which is divided into two groups, left and right, respectively connected to the low-temperature discharge port 51 and the high-temperature discharge port 52, wherein the low-temperature feed port 4 is connected to the low-temperature discharge port 51 through the discharge structure 5 on the left, and the high-temperature feed port 3 is connected to the high-temperature discharge port 52 through the discharge structure 5 on the right, so that the rich oil entering through the low-temperature feed port 4 flows out through the low-temperature discharge port 51 above the heat exchange bin 1, and the lean oil entering through the high-temperature feed port 3 flows out through the high-temperature discharge port 52 below the heat exchange bin 1, completing the heat exchange process between the lean oil and the rich oil.

[0043] Example 2: Please refer to Figure 1 - Figure 5 As shown, the crude benzene processing heat exchanger also includes a crude benzene processing heat exchanger operation control system, including a flow monitoring unit, a heat exchange monitoring unit and a pressure monitoring unit;

[0044] The flow monitoring unit collects the liquid flow passing through the high-temperature feed port 3 through a liquid flow meter installed at the high-temperature feed port 3. The flow monitoring unit records the collected liquid flow in sections, and obtains flow statistics data in multiple time periods of the same length. The flow monitoring unit performs arithmetic averaging on the multiple flow statistics data to obtain the high-temperature feed mean value;

[0045] Similarly, the flow monitoring unit collects the flow in the high-temperature outlet 52, the low-temperature feed port 4 and the low-temperature outlet 51 through the liquid flow meters installed at the high-temperature outlet 52, the low-temperature feed port 4 and the low-temperature outlet 51, and calculates the high-temperature outlet average, the low-temperature feed average and the low-temperature outlet average;

[0046] The flow monitoring unit compares the high-temperature feed average and the high-temperature discharge average to obtain the high-temperature fluid difference. If the high-temperature fluid difference is within the allowable range, a high-temperature channel normal signal is generated. If the high-temperature fluid difference is not within the allowable range, a high-temperature channel abnormal signal is generated.

[0047] The flow monitoring unit compares the low-temperature feed mean value with the low-temperature discharge mean value to obtain the low-temperature fluid difference. If the low-temperature fluid difference is within the allowable range, a low-temperature channel normal signal is generated. If the high-temperature fluid difference is not within the allowable range, a low-temperature channel abnormal signal is generated.

[0048] When the flow monitoring unit generates any one of the high-temperature channel abnormal signal or the low-temperature channel abnormal signal, a cross-talk alarm is generated and sent to the control platform, which displays the cross-talk alarm.

[0049] Example 3: Please refer to Figure 1 - Figure 5 As shown, the heat exchange monitoring unit collects the temperatures of the high-temperature feed port 3, the high-temperature discharge port 52, the low-temperature feed port 4 and the low-temperature discharge port 51, calculates the high-temperature difference according to the temperature difference between the high-temperature feed port 3 and the high-temperature discharge port 52, and calculates the low-temperature difference according to the temperature difference between the low-temperature feed port 4 and the low-temperature discharge port 51;

[0050] The heat exchange monitoring unit monitors the liquid flow rate in the high-temperature feed port 3 and the low-temperature feed port 4 through a flow meter, and simultaneously obtains the length of the spiral path in the preset heat exchange bin 1, thereby calculating the time required for the liquid to pass through the heat exchange bin 1 according to the length of the spiral path and the flow rates of the high-temperature liquid and the low-temperature liquid, and obtaining the high-temperature flow time and the low-temperature flow time;

[0051] The heat exchange monitoring unit calculates the heat exchange efficiency θ through the high temperature difference, low temperature difference, high temperature flow time and low temperature flow time. , where Q is the preset coefficient, T is the high temperature difference, t is the low temperature difference, V1 is the high temperature flow time, V2 is the low temperature flow time, and the calculations in the formula are all dimensionless calculations, and only the numerical part is referenced;

[0052] The heat exchange monitoring unit compares the heat exchange coefficient obtained through the heat exchange model analysis with the set nominal heat exchange coefficient of the heat exchange bin 1. If the difference between the heat exchange coefficient and the nominal heat exchange coefficient is greater than the set threshold, a heat exchange abnormality signal is generated. If the difference between the heat exchange coefficient and the nominal heat exchange coefficient is not greater than the set threshold, a heat exchange normal signal is generated.

[0053] After obtaining the abnormal heat exchange signal, the heat exchange monitoring unit sends the abnormal heat exchange signal to the control platform, and the control platform displays the abnormal heat exchange signal.

[0054] Example 4: Please refer to Figure 1 - Figure 5 As shown, the pressure monitoring unit continuously records the liquid pressure discharged from the high-temperature outlet 52 and the low-temperature outlet 51 through the pressure sensor as high-temperature pressure and low-temperature pressure. The pressure monitoring unit records all the acquired high-temperature pressures and low-temperature pressures, and calculates the variance of the recorded data through the variance formula to obtain the high-temperature variance and the low-temperature variance. The high-temperature variance is used to represent the fluctuation of the high-temperature pressure, and the low-temperature variance is used to represent the fluctuation of the low-temperature pressure.

[0055] The pressure monitoring unit compares the high temperature variance with the set threshold value. If the high temperature variance is greater than the set threshold value, a high temperature pressure fluctuation signal is generated. If the high temperature variance is not greater than the set threshold value, a high temperature pressure stability signal is generated.

[0056] The pressure monitoring unit compares the low temperature variance with the set threshold value, and generates a low temperature pressure fluctuation signal if the low temperature variance is greater than the set threshold value, and generates a low temperature pressure stability signal if the low temperature variance is not greater than the set threshold value;

[0057] After generating the high-temperature pressure fluctuation signal, the pressure monitoring unit adjusts the pressure in the low-temperature spiral channel. If the high-temperature pressure shows a follow-up phenomenon when the pressure in the low-temperature spiral channel is reciprocated, a leakage signal is generated, wherein the follow-up phenomenon refers to that after the pressure in the low-temperature spiral channel decreases, the average value of the high-temperature pressure decreases, and after the pressure in the low-temperature spiral channel increases, the average value of the high-temperature pressure increases;

[0058] Similarly, after the low-temperature pressure fluctuation signal is generated, the pressure in the high-temperature spiral channel is adjusted. If the low-temperature pressure shows a follow-up phenomenon, a leakage signal is generated.

[0059] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A crude benzene processing heat exchanger for preventing leakage of lean oil and rich oil, comprising a heat exchange chamber (1), characterized in that: The heat exchange chamber (1) is made of two sets of parallel metal plates which are spirally connected to form two sets of spiral channels in the heat exchange chamber (1), the two sets of spiral channels being respectively a high-temperature spiral channel and a low-temperature spiral channel; A high-temperature feed port (3) and a low-temperature feed port (4) are respectively installed at both ends of the heat exchange bin (1); a bin cover (2) is installed on both upper and lower sides of the heat exchange bin (1); a low-temperature discharge port (51) is installed on the upper bin cover (2), and a high-temperature discharge port (52) is installed on the lower bin cover (2); Also included is a crude benzene processing heat exchanger operation control system, including a flow monitoring unit, a heat exchange monitoring unit, a pressure monitoring unit and a control platform; The flow monitoring unit is used to monitor and compare the liquid flow in the heat exchange chamber (1) to determine whether there are abnormalities in the high-temperature channel and the low-temperature channel; The heat exchange monitoring unit is used to obtain the heat exchange coefficient of the heat exchange bin (1), and generate a normal heat exchange signal or an abnormal heat exchange signal based on the heat exchange coefficient analysis; The pressure monitoring unit is used to monitor the pressure at the outlet of the heat exchange chamber (1). When the pressure is abnormal, the pressure is adjusted and tested to confirm whether there is leakage. The pressure monitoring unit records the liquid pressure at the high-temperature discharge port (52) and the low-temperature discharge port (51) as the high-temperature pressure and the low-temperature pressure, and the pressure monitoring unit calculates the variance of all the acquired high-temperature pressures and low-temperature pressures using a variance formula to obtain the high-temperature variance and the low-temperature variance; The pressure monitoring unit compares the high temperature variance with a set threshold value, and generates a high temperature pressure fluctuation signal or a high temperature pressure stability signal according to the comparison result; The pressure monitoring unit compares the low temperature variance with a set threshold value, and generates a low temperature pressure fluctuation signal or a low temperature pressure stability signal according to the comparison result; After generating the high-temperature pressure fluctuation signal, the pressure monitoring unit adjusts the pressure in the low-temperature spiral channel. If the high-temperature pressure shows a follow-up phenomenon when the pressure in the low-temperature spiral channel is reciprocated, a leakage signal is generated, wherein the follow-up phenomenon refers to that after the pressure in the low-temperature spiral channel decreases, the average value of the high-temperature pressure decreases, and after the pressure in the low-temperature spiral channel increases, the average value of the high-temperature pressure increases; After the low-temperature pressure fluctuation signal is generated, the pressure in the high-temperature spiral channel is adjusted. If the low-temperature pressure shows a follow-up phenomenon, a leakage signal is generated.

2. The crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil according to claim 1 is characterized in that: The heat exchange bin body (1) has a discharge structure at the center, and the discharge structure (5) is divided into two groups, the left and the right. The low-temperature feed port (4) is connected to the low-temperature discharge port (51) through the discharge structure (5) on the left, and the high-temperature feed port (3) is connected to the high-temperature discharge port (52) through the discharge structure (5) on the right.

3. The crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil according to claim 1 is characterized in that: The flow monitoring unit collects the liquid flow passing through the high-temperature feed port (3) and records it in sections, respectively obtaining flow statistics data in multiple time periods of the same length, and the flow monitoring unit performs arithmetic averaging on the multiple flow statistics data to obtain a high-temperature feed mean value; The flow monitoring unit collects the flow rates in the high-temperature discharge port (52), the low-temperature feed port (4) and the low-temperature discharge port (51) through liquid flow meters installed at the high-temperature discharge port (52), the low-temperature feed port (4) and the low-temperature discharge port (51), and calculates the high-temperature discharge mean, the low-temperature feed mean and the low-temperature discharge mean.

4. The crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil according to claim 3 is characterized in that: The flow monitoring unit compares the high-temperature feed average and the high-temperature discharge average to obtain a high-temperature fluid difference. If the high-temperature fluid difference is not within an allowable range, a high-temperature channel abnormal signal is generated; The flow monitoring unit compares the low-temperature feed average with the low-temperature discharge average to obtain a low-temperature fluid difference. If the high-temperature fluid difference is not within an allowable range, a low-temperature channel abnormal signal is generated; The flow monitoring unit generates a cross-talk alarm when generating any one of a high-temperature channel abnormal signal or a low-temperature channel abnormal signal.

5. The crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil according to claim 1 is characterized in that: The heat exchange monitoring unit collects the temperatures at the high-temperature feed port (3), the high-temperature discharge port (52), the low-temperature feed port (4) and the low-temperature discharge port (51), calculates the temperature difference between the high-temperature feed port (3) and the high-temperature discharge port (52) to obtain a high-temperature difference, and calculates the temperature difference between the low-temperature feed port (4) and the low-temperature discharge port (51) to obtain a low-temperature difference; The heat exchange monitoring unit obtains the liquid flow rate in the high-temperature feed port (3) and the low-temperature feed port (4) and the length of the spiral path in the preset heat exchange chamber (1), and calculates the time required for the liquid to pass through the heat exchange chamber (1) based on the length and flow rate of the spiral path to obtain the high-temperature flow time and the low-temperature flow time.

6. The crude benzene processing heat exchanger for avoiding leakage of lean oil and rich oil according to claim 5 is characterized in that: The heat exchange monitoring unit calculates the heat exchange efficiency through the high temperature difference, the low temperature difference, the high temperature flow time and the low temperature flow time through a preset formula; The heat exchange monitoring unit compares the heat exchange coefficient with the set nominal heat exchange coefficient to generate a heat exchange abnormality signal or a heat exchange normal signal.

Images