Biodiesel distillation production safety device

Abstract

The present invention discloses a biodiesel distillation production safety device, comprising a nitrogen supply device, a temperature control system, a crude biodiesel cooler, and a skylight lightning protection device. The temperature control system includes a digital thermometer with a temperature sensor, a programmable logic controller (PLC), a computer, and an electronic control cabinet. Signal lines connect the PLC to the digital thermometer and the computer. A nitrogen blanketing nitrogen inlet, a crude biodiesel inlet, a nitrogen blanketing breathing valve outlet, a nitrogen blanketing nitrogen release valve outlet, and a crude biodiesel return port for shutdown cooling are located near the edge of the crude biodiesel tank top. A temperature measuring port is located in the lower middle portion of one side of the tank. The skylight lightning protection device is located around the crude biodiesel tank. A temperature control system is provided on the cooling water inlet pipe of the crude biodiesel cooler, connected to the signal line of the digital thermometer at the temperature measuring port of the crude biodiesel tank. This device can reduce energy consumption when the biodiesel distillation system is shut down for maintenance and rapid cooling, ensuring lightning protection and explosion-proof operation of the crude methyl ester tank area and preventing damage to the structured packing of the distillation column during the cooling process.

Description

Technical Field

[0001] The invention relates to the technical field of production devices for producing biodiesel by utilizing waste animal and vegetable oils and fats, and in particular to a biodiesel distillation production safety device. Background Art

[0002] Existing biodiesel production mainly uses waste animal and plant oils as raw materials, and produces crude fatty acid methyl esters through a two-step chemical process of esterification and transesterification. After the crude methyl ester, also known as crude biodiesel, enters the falling film flash evaporation to remove low-boiling substances such as water and methanol, it is then heated to 250°C with heat transfer oil and enters the biodiesel distillation tower. Under a negative pressure of -0.05MPa, different types of qualified biodiesel products are obtained from different distillation towers according to their boiling points. Finally, the high-boiling-point heavy oil is discharged from the bottom of the distillation tower. Since waste animal and vegetable oils still contain a small amount of impurities after treatment, some side reactions are likely to occur during the esterification and transesterification reactions to produce a small amount of soap, gum and other emulsifying substances. After these substances are separated by a butterfly centrifuge, the crude methyl ester still contains a small amount of soap, gum and other impurities ≤0.05% that cannot be removed. These impurities are adsorbed on the distillation tower packing and the wall of the distillation tower reboiler tubes during the biodiesel production process. After a period of production, they will affect the heat exchange effect of the reboiler and the production efficiency of the distillation tower, requiring shutdown for cooling and maintenance of the tower. Currently, the shutdown of biodiesel distillation for cooling generally utilizes the original heat exchange area. The cooling of small heavy oil coolers has the following defects: First, not only is the tower washing time long and the energy consumption high, but also because the crude methyl ester tank is not equipped with a nitrogen sealing safety device, because the crude methyl ester contains ≤1.2% methanol, the methanol and air in the upper space of the crude methyl ester tank are prone to form explosive gas, which is easy to cause safety accidents when encountering static electricity, high temperature and lightning strikes; second, when the distillation tower is shut down for maintenance and cooling, the crude methyl ester is prone to overheating after heat exchange and returning to the crude methyl ester tank, posing a safety hazard; third, when the distillation tower is shut down for maintenance and cooling and breaking the vacuum, it is easy to cause local spontaneous combustion of the structured packing and burn the structured packing. Summary of the Invention

[0003] The present invention aims to provide a biodiesel distillation production safety device that is easy to operate, efficient, safe and reliable to use, thereby reducing energy consumption when the biodiesel distillation system is shut down for maintenance and rapid cooling, ensuring lightning protection and explosion-proof safe operation of the crude methyl ester tank area, and preventing the structured packing of the distillation column from being burned during the cooling process, thereby increasing the service life of the equipment.

[0004] To achieve the above objectives, the biodiesel distillation production safety device of the present invention includes a distillation tower 1, a reboiler 2, a high-temperature circulation pump 3, a heavy oil cooler 4, a heavy oil trough 5, a heavy oil pump 6, a biodiesel receiving tank 7, a biodiesel discharge pump 8, a tower washing receiving tank 9, a tower washing receiving tank pump 10, a tower washing hot water tank 11, a tower washing hot water tank pump 12, a crude biodiesel feed pump 13, a crude biodiesel tank 14, a nitrogen supply device 15, a breathing valve 16, a nitrogen release valve 17, a digital thermometer 18, a temperature control system 19, a crude biodiesel cooler 20 and a skylight lightning protection device; the temperature control system 19 includes a digital thermometer with a temperature sensor 18. A program control system PLC, a computer, and an electric control cabinet. Signal lines connect the PLC to the digital thermometer 18 and the computer. The distillation tower 1 is provided with a crude methyl ester feed inlet a in the middle, a distillation tower vacuum outlet b at the top, a distillation tower biodiesel outlet c at the upper middle portion, a reboiler vapor phase inlet d at the side of the lower middle portion, a distillation tower heavy oil outlet e at the bottom, and a reboiler circulation port f at the center of the bottom of the distillation tower. The heavy oil cooler 4 is provided with a heavy oil inlet g1 at the top, a heavy oil outlet g2 at the bottom, and a heavy oil cooler cooling water outlet h1 at the upper left portion. A heavy oil cooler cooling water inlet h2 is provided at the lower left part; a heavy oil tank heavy oil inlet pipe i1 is provided at the upper left part of the heavy oil tank 5, a heavy oil tank tail gas outlet pipe i2 is provided at the upper right part, and a heavy oil tank heavy oil outlet i3 is provided at the bottom; a biodiesel receiving tank biodiesel inlet pipe j1 is provided at the upper left part of the biodiesel receiving tank 7, a biodiesel receiving tank tail gas outlet pipe j2 is provided at the upper right part, and a biodiesel receiving tank biodiesel outlet j3 is provided at the bottom; the lower part of the washing tower receiving tank 9 is conical, and a washing tower receiving tank washing tower water feed pipe k is provided at the top near the edge of the washing tower receiving tank, and a washing tower receiving tank water feed pipe k is provided at the top center of the washing tower receiving tank. A tower washing receiving tank tail gas outlet pipe l; a sampling tube m is provided at the lower part of the side of the tower washing receiving tank, a tower washing receiving tank oil discharge port n is provided on the other side, and a tower washing receiving tank wastewater outlet pipe o is provided at the conical bottom of the tower washing receiving tank; a tower washing hot water tank water feed pipe p1 is provided at the top near the edge of the tower washing hot water tank 11, a tower washing hot water tank water vapor tail gas outlet pipe p2 is provided at the center of the tank top, a steam heating coil is installed in the tower washing hot water tank tank, a tower washing hot water tank steam inlet pipe p3 is provided at the lower part of one side of the hot water tank, and a tower washing hot water tank steam outlet pipe p4 is provided at the lower part of the other side; a water temperature measuring tube p5 is provided at the lower part of the side of the tower washing hot water tank, and a tower washing hot water tank outlet pipe p6 is provided at the bottom of the tank;The lower part of the crude biodiesel tank 14 is in a cone shape, and a nitrogen-sealed nitrogen inlet r1, a crude biodiesel inlet r2, a nitrogen-sealed breathing valve outlet r3, a nitrogen-sealed nitrogen relief valve outlet r4 and a shutdown cooling crude biodiesel reflux inlet r5 are provided near the edge of the tank top. A crude biodiesel tank temperature measuring port s is provided in the lower middle part of one side of the crude biodiesel tank 14, and a digital thermometer 18 is installed on the crude biodiesel tank temperature measuring port s. A crude biodiesel tank crude biodiesel outlet u is provided between the crude biodiesel tank temperature measuring port s and the cone connection. The crude biodiesel tank 14 is provided with a crude biodiesel sampling port t at the same side and height as the bottom of the crude biodiesel inlet r2 pipe. A glycerol separation is provided at the cone bottom of the crude biodiesel tank 14. Outlet v; The upper part of the crude biodiesel cooler 20 is provided with a crude biodiesel cooler crude biodiesel outlet w, the lower part is provided with a crude biodiesel cooler crude biodiesel inlet z, the upper left part is provided with a crude biodiesel cooler cooling water outlet x, and the lower left part is provided with a crude biodiesel cooler cooling water inlet y; The skylight lightning protection device is provided around the crude biodiesel tank, which includes a lower device rod 22 and an upper skylight-Ⅰ type lightning protection component 21; The heavy oil outlet e of the distillation tower is divided into two paths, one of which is connected to the washing tower receiving tank washing tower water feed pipe k after passing through the valve, the washing tower receiving tank oil discharge port n and the washing tower receiving tank wastewater outlet pipe o are respectively merged after connecting the valve, and then connected to the washing tower receiving The other is connected to the heavy oil cooler heavy oil inlet g1 after passing through the valve, the heavy oil cooler heavy oil outlet g2 is connected to the heavy oil tank heavy oil inlet pipe i1, and the heavy oil tank heavy oil outlet i3 is connected to the crude biodiesel cooler crude biodiesel inlet z after connecting to the heavy oil pump 6; the crude biodiesel cooler crude biodiesel outlet w is connected to the shutdown cooling crude biodiesel reflux inlet r5 of the crude biodiesel tank 14, and the nitrogen supply device 15 is connected to the nitrogen blanketing nitrogen inlet r1; the crude biodiesel tank crude biodiesel outlet u is connected to the inlet of the crude biodiesel feed pump 13, and the pipeline of the cooling water inlet y of the crude biodiesel cooler is provided with a digital temperature display provided on the temperature measuring port s of the crude biodiesel tank. A signal line from the thermometer 18 is connected to the temperature control system 19. The tower wash hot water tank outlet pipe p6 is connected to the inlet of the tower wash hot water tank pump 12. The outlet pipes of the tower wash hot water tank pump 12 and the crude biodiesel feed pump 13 are combined after connecting a valve and then connected to the crude methyl ester feed port a of the distillation tower. The distillation tower reboiler circulation port f is connected to the high-temperature circulation pump 3 and the reboiler 2, and then to the reboiler vapor phase inlet d of the distillation tower. The distillation tower biodiesel outlet c is connected to the biodiesel inlet pipe j1 of the biodiesel receiving tank. The biodiesel outlet j3 of the biodiesel receiving tank is connected to the biodiesel discharge pump 8 and then to the product tank area. The distillation tower biodiesel outlet c is also connected to the cooling water pipe interface used for tower wash cooling.

[0005] The heavy oil outlet e of the distillation tower is located at the bottom of the distillation tower, 150 mm from the center line; the water temperature measuring tube p5 is located at the lower side of the tower washing hot water tank, 400 mm from the bottom of the tank.

[0006] The bottom end of the inlet pipe of the crude biodiesel inlet r2 is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part. The bottom of the pipe is 5.5 meters away from the tank top.

[0007] The bottom end of the inlet pipe of the shutdown cooling crude biodiesel reflux inlet r5 is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part. The bottom of the pipe is 5.5 meters away from the tank top.

[0008] The protection range of the skylight lightning protection device is 70 degrees.

[0009] The above-mentioned skylight lightning protection device, namely the skylight-Ⅰ type direct lightning protection device, is an existing technology that can be purchased on the market and is manufactured by Chengdu Dongfang Hanyi Technology Development Co., Ltd.

[0010] The upper control computer of the above-mentioned temperature control system is equipped with Tianhong Industrial Configuration Software V1.0. The function of this software system is to display, record and control the data of each process point. The software developer is Longyan Tianhong Computer Technology Co., Ltd., and it was launched in May 2018, which is an existing technology; the above-mentioned program control system PLC was developed by Longyan Tianhong Computer Technology Co., Ltd., the PLC brand is Siemens, the CPU and acquisition control module of the PLC system are Siemens' S7-1200 series general products, and the PLC software programming is written by Longyan Tianhong Computer Technology Co., Ltd. according to requirements; all software and hardware with computer programs are existing technologies that can be purchased on the market.

[0011] The biodiesel distillation production safety device of the present invention has the following technical features and beneficial effects:

[0012] 1. By adding a crude biodiesel cooler 20 and a crude biodiesel cooler water temperature automatic control device, the temperature can be quickly lowered and energy consumption can be reduced, the downtime of biodiesel distillation maintenance can be reduced, and the temperature of crude biodiesel returned to the crude biodiesel tank for cooling can be ensured to be below the flash point temperature, thereby avoiding accidents caused by high-temperature flash explosion of crude biodiesel;

[0013] 2. By adding a nitrogen sealing device to the crude biodiesel tank, the oxygen content in the crude biodiesel tank is ensured to be qualified, and no explosive gas will be formed to cause accidents;

[0014] 3. By adding a Sky Curtain-I type direct lightning protection device around the crude biodiesel tank, the crude biodiesel tank is protected against lightning strikes and the occurrence of lightning safety accidents is avoided.

[0015] 4. Adding a hot water tank for washing the tower can improve the washing effect and prevent the structured packing of the distillation tower from being burned during the cooling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the biodiesel distillation production safety device of the present invention.

[0017] Figure 2 yes Figure 1 Schematic diagram of the enlarged structure of the middle distillation tower.

[0018] Figure 3 yes Figure 1 Enlarged structural diagram of medium and heavy oil cooler.

[0019] Figure 4 yes Figure 1 Schematic diagram of the enlarged structure of the medium and heavy oil trough.

[0020] Figure 5 yes Figure 1 Schematic diagram of the enlarged structure of the biodiesel receiving tank.

[0021] Figure 6 yes Figure 1 Schematic diagram of the enlarged structure of the intermediate scrubber receiving tank.

[0022] Figure 7 yes Figure 1 Schematic diagram of the enlarged structure of the hot water tank of the middle washing tower.

[0023] Figure 8 yes Figure 1 Schematic diagram of the enlarged structure of the medium-coarse biodiesel tank.

[0024] Figure 9 yes Figure 1 A magnified schematic diagram of the temperature control system for the medium crude biodiesel tank and crude biodiesel cooler.

[0025] Figure 10 yes Figure 1 Enlarged structural diagram of the medium-coarse biodiesel cooler.

[0026] Figure 11 yes Figure 1 Enlarged structural diagram of the central skylight lightning protection device.

[0027] Reference numerals: distillation tower 1, reboiler 2, high-temperature circulation pump 3, heavy oil cooler 4, heavy oil ground tank 5, heavy oil pump 6, biodiesel receiving tank 7, biodiesel discharge pump 8, tower washing receiving tank 9, tower washing receiving tank pump 10, tower washing hot water tank 11, tower washing hot water tank pump 12, crude biodiesel feed pump 13, crude biodiesel tank 14, nitrogen supply device 15, breathing valve 16, nitrogen release valve 17, digital thermometer 18, temperature control system 19, crude biodiesel cooler 20, skylight-Ⅰ type lightning protection component 21, Device rod 22, distillation tower crude methyl ester feed inlet a, distillation tower vacuum outlet b, distillation tower biodiesel outlet c, reboiler vapor phase inlet d, distillation tower heavy oil outlet e, reboiler circulation port f, heavy oil cooler heavy oil inlet g1, heavy oil cooler heavy oil outlet g2, heavy oil cooler cooling water outlet h1, heavy oil cooler cooling water inlet h2, heavy oil ground tank heavy oil inlet pipe i1, heavy oil ground tank tail gas outlet pipe i2, heavy oil ground tank heavy oil outlet i3, biodiesel receiving tank biodiesel inlet pipe j1, biodiesel receiving tank tail gas outlet pipe j2, biodiesel receiving tank biodiesel outlet j3, tower washing receiving tank tower washing water feed pipe k, tower washing receiving tank tail gas outlet pipe l, sampling pipe m, tower washing receiving tank oil outlet n, tower washing receiving tank wastewater outlet pipe o, tower washing hot water tank water feed pipe p1, tower washing hot water tank water vapor tail gas outlet pipe p2, tower washing hot water tank steam inlet pipe p3, tower washing hot water tank steam outlet pipe p4, water temperature measuring pipe p5, tower washing hot water tank outlet pipe p6, nitrogen blanketing nitrogen inlet r1, crude biodiesel inlet Port r2, nitrogen-sealed breathing valve outlet r3, nitrogen-sealed nitrogen release valve outlet r4, shutdown cooling crude biodiesel reflux inlet r5, crude biodiesel tank temperature measuring port s, crude biodiesel tank crude biodiesel outlet u, crude biodiesel sampling port t, glycerin separation outlet v, crude biodiesel cooler crude biodiesel outlet w, crude biodiesel cooler crude biodiesel inlet z, crude biodiesel cooler cooling water outlet x, crude biodiesel cooler cooling water inlet y, T-temperature, I-display, V-regulating valve, C-control, A-alarm. DETAILED DESCRIPTION

[0028] The biodiesel distillation production safety device of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Figures 1-11As shown, the biodiesel distillation production safety device of the present invention includes a distillation tower 1, a reboiler 2, a high-temperature circulation pump 3, a heavy oil cooler 4, a heavy oil trough 5, a heavy oil pump 6, a biodiesel receiving tank 7, a biodiesel discharge pump 8, a tower washing receiving tank 9, a tower washing receiving tank pump 10, a tower washing hot water tank 11, a tower washing hot water tank pump 12, a crude biodiesel feed pump 13, a crude biodiesel tank 14, a nitrogen supply device 15, a breathing valve 16, a nitrogen release valve 17, a digital thermometer 18, a temperature control system 19, a crude biodiesel cooler 20 and a skylight lightning protection device; the temperature control system 19 includes a digital thermometer 18 with a temperature sensor, a program control system PLC, a computer and an electric control cabinet, and the PLC is connected to the digital thermometer 18 and the computer. Signal line connection; the middle part of the distillation tower 1 is provided with a distillation tower crude methyl ester feed inlet a, the top is provided with a distillation tower vacuum outlet b, the middle and upper part is provided with a distillation tower biodiesel outlet c, the middle and lower side is provided with a reboiler vapor phase inlet d, the bottom of the distillation tower is provided with a distillation tower heavy oil outlet e 150 mm from the center line, and the center of the bottom of the distillation tower is provided with a reboiler circulation port f; the upper part of the heavy oil cooler 4 is provided with a heavy oil cooler heavy oil inlet g1, the lower part is provided with a heavy oil cooler heavy oil outlet g2, the upper left part is provided with a heavy oil cooler cooling water outlet h1, and the lower left part is provided with a heavy oil cooler cooling water inlet h2; the upper left part of the heavy oil trough 5 is provided with a heavy oil trough heavy oil inlet pipe i1, and the upper right part is provided with a heavy oil trough tail gas outlet pipe i 2, a heavy oil trough heavy oil outlet i3 is provided at the bottom; a biodiesel receiving tank biodiesel inlet pipe j1 is provided at the upper left part of the biodiesel receiving tank 7, a biodiesel receiving tank tail gas outlet pipe j2 is provided at the upper right part, and a biodiesel receiving tank biodiesel outlet j3 is provided at the bottom; the lower part of the washing tower receiving tank 9 is cone-shaped, and a washing tower receiving tank washing tower water feed pipe k is provided at the top near the edge of the washing tower receiving tank, and a washing tower receiving tank tail gas outlet pipe l is provided at the top center of the washing tower receiving tank; a sampling tube m is provided at the lower part of the side of the washing tower receiving tank, and a washing tower receiving tank oil outlet n is provided on the other side, and a washing tower receiving tank wastewater outlet pipe o is provided at the cone bottom of the washing tower receiving tank; a washing tower hot water tank water feed pipe p1 is provided at the top near the edge of the washing tower hot water tank 11, A water vapor tail gas outlet pipe p2 for a tower washing hot water tank is provided at the top center, a steam heating coil is installed in the tower washing hot water tank tank, a steam inlet pipe p3 for the tower washing hot water tank is provided at the lower part of one side of the hot water tank, and a steam outlet pipe p4 for the tower washing hot water tank is provided at the lower part of the other side. The function of the steam heating coil is to adjust the temperature in the hot water tank to meet the set temperature by passing steam to achieve the tower washing effect; a water temperature measuring tube p5 is provided at the lower part of the side of the tower washing hot water tank 400 mm from the bottom of the tank, and a tower washing hot water tank outlet pipe p6 is provided at the bottom of the tank; the lower part of the crude biodiesel tank 14 is conical, and a nitrogen-sealed nitrogen inlet r1, a crude biodiesel inlet r2, a nitrogen-sealed breathing valve outlet r3, a nitrogen-sealed nitrogen relief valve outlet r4 and a shutdown cooling crude biodiesel reflux inlet r5 are provided near the edge of the tank top;The bottom end of the inlet pipe of the crude biodiesel inlet r2 is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part. The bottom of the pipe is 5.5 meters away from the tank top, so that the crude biodiesel can be mixed here; the bottom end of the inlet pipe of the shutdown cooling crude biodiesel reflux inlet r5 is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part, and the bottom of the pipe is 5.5 meters away from the tank top; a crude biodiesel tank temperature measuring port s is provided in the lower middle part of one side of the crude biodiesel tank 14, and a digital thermometer 18 is installed on the crude biodiesel tank temperature measuring port s. A crude biodiesel tank crude biodiesel outlet u is provided between the crude biodiesel tank temperature measuring port s and the cone connection. The crude biodiesel tank 14 is provided with a crude biodiesel sampling port t at the same height as the bottom of the crude biodiesel inlet r2. The cone bottom of the crude biodiesel tank 14 is provided with a glycerol separation outlet v; the upper part of the crude biodiesel cooler 20 is provided with a crude biodiesel cooler crude biodiesel outlet w, the lower part is provided with a crude biodiesel cooler crude biodiesel inlet z, the upper left part is provided with a crude biodiesel cooler cooling water outlet x, and the lower left part is provided with a crude biodiesel cooler cooling water inlet y; the skylight lightning protection device is provided around the crude biodiesel tank, and it includes a lower device rod 22 and an upper skylight-Ⅰ type lightning protection component 21, and its protection range is 70 degrees. The skylight lightning protection device uses an electronic switch to monitor the induced air charge accumulated around the crude biodiesel tank in real time. When the air charge reaches 8,500 volts, it is turned on. Before reaching the breakdown voltage, the ground charge is neutralized (blocked) The distillation tower heavy oil outlet e is divided into two paths, one of which is connected to the tower washing receiving tank water feed pipe k after passing through a valve, and the oil discharge port n of the tower washing receiving tank and the waste water outlet pipe o of the tower washing receiving tank are respectively merged after connecting the valve, and then connected to the tower washing receiving tank pump 10, and the heavy oil is connected to the waste oil tank area for treatment, and the waste water is connected to the wastewater sewage station for treatment; the other path is connected to the heavy oil inlet g1 of the heavy oil cooler after passing through a valve, and the heavy oil outlet g2 of the heavy oil cooler is connected to the heavy oil inlet pipe i1 of the heavy oil trough, and the heavy oil outlet of the heavy oil trough is connected to the heavy oil outlet pipe i2 of the heavy oil trough. i3 is connected to the crude biodiesel inlet z of the crude biodiesel cooler after being connected to the heavy oil pump 6; the crude biodiesel outlet w of the crude biodiesel cooler is connected to the shutdown cooling crude biodiesel reflux inlet r5 of the crude biodiesel tank 14, and the nitrogen supply device 15 is connected to the nitrogen blanketing nitrogen inlet r1; the crude biodiesel outlet u of the crude biodiesel tank is connected to the inlet of the crude biodiesel feed pump 13, and the pipeline of the cooling water inlet y of the crude biodiesel cooler is provided with a temperature control system 19 connected to the signal line of the digital thermometer 18 provided at the temperature measuring port s of the crude biodiesel tank; the tower washing hot water tank outlet pipe p6 is connected to the inlet of the tower washing hot water tank pump 12, and the outlet pipes of the tower washing hot water tank pump 12 and the crude biodiesel feed pump 13 are merged after connecting the valve, and then connected to the crude methyl ester feed port a of the distillation tower;The distillation tower reboiler circulation port f is connected to the high-temperature circulation pump 3 and reboiler 2, and then to the distillation tower reboiler vapor phase inlet d. The distillation tower biodiesel outlet c is connected to the biodiesel inlet pipe j1 of the biodiesel receiving tank. The biodiesel outlet j3 of the biodiesel receiving tank is connected to the biodiesel discharge pump 8 and then to the product tank area. The distillation tower biodiesel outlet c is also connected to the cooling water pipe interface used for tower washing and cooling.

[0030] Heavy oil accounts for about 10% of the biodiesel production process. The heat exchange area of the heavy oil cooler 4 is designed to be appropriate based on 15% of the daily biodiesel production capacity and can only be used for normal production. If the heat exchange area is too large, the redundant tubes will be blocked and cause tube leakage.

[0031] After the tower washing water from the shutdown cooling stays in the tower washing receiving tank 9 for 36 hours, the wastewater is discharged from the cone bottom wastewater outlet pipe o of the tower washing receiving tank 9 to the sewage station. When the tower washing water is sampled and analyzed by the sampling pipe m of the tower washing receiving tank 9 and contains oil, the water discharge is stopped and the waste oil is discharged from the oil outlet n of the receiving tank 9 back to the production for reuse.

[0032] When the pressure in the crude biodiesel tank 14 is less than 1200Pa, the nitrogen inlet valve of the nitrogen supply device 15 is opened, and when the nitrogen pressure in the crude biodiesel tank 14 reaches 1200Pa, the nitrogen supply is automatically stopped; when the pressure in the crude biodiesel tank 14 is ≥3000Pa, the nitrogen sealing breathing valve 16 is automatically opened to release the pressure, and when the pressure in the crude biodiesel tank 14 is less than 3000Pa, the nitrogen sealing breathing valve 16 is automatically closed; when the pressure in the crude biodiesel tank 14 is greater than 2700Pa, the nitrogen sealing nitrogen release valve 17 is automatically opened to release the pressure, and when the pressure in the crude biodiesel tank 14 is ≤2700Pa, the nitrogen sealing nitrogen release valve 17 is automatically closed to maintain the pressure in the crude biodiesel tank 14 at 1200~2700.

[0033] According to experimental measurements of crude biodiesel, the flash point of crude biodiesel is between 67 and 70°C. Controlling the temperature of crude biodiesel tank 14 between 62 and 64°C facilitates glycerin precipitation in crude biodiesel, saves energy, and ensures the safety of crude biodiesel tank 14. The operating principle of temperature control system 19 is to set a temperature limit for crude biodiesel in crude biodiesel tank 14. The temperature sensor sends a signal to the PLC, automatically opening temperature control valve TV and automatically adjusting the cooling water valve to begin cooling the crude biodiesel in crude biodiesel cooler 20, thereby ensuring the temperature limit for crude biodiesel in crude biodiesel tank 14.

[0034] The purpose of providing the crude biodiesel cooler 20 is to utilize the crude biodiesel in the crude biodiesel tank 14 to cool the system temperature during shutdown. The original heavy oil cooler 4 has insufficient heat exchange area, and the crude biodiesel refluxed after heat exchange is higher than the flash point of crude biodiesel, which is not conducive to production safety. The protection range of the skylight lightning protection device is 70 degrees. The Skylight-I type direct lightning protection device is a device that uses an electronic switch to monitor the induced air charge accumulated around the crude biodiesel tank in real time. When the air charge reaches 8,500 volts (it will conduct), before reaching the breakdown voltage (generally tens of thousands of volts), the ground charge is turned on to neutralize (intercept) the downward leader of the lightning, preventing its ground tip from generating a counterattack (upward leader), and preventing the establishment of an air ionization channel from the thundercloud to the ground, thereby preventing the charge in the thundercloud, i.e., lightning, from being discharged to the ground, thereby ensuring the safety of the crude biodiesel tank.

[0035] The specific operation process during production is as follows:

[0036] In the middle and late stages of biodiesel distillation production, a certain amount of crude biodiesel soap, glue, carbon residue and other impurities will be adsorbed on the structured packing in the distillation tower 1 and the wall of the reboiler 2, affecting the heat exchange effect of the reboiler and the quality of the distillation tower product. It is necessary to shut down the machine for cooling and overhauling the tower and to stop the thermal oil boiler in the heating workshop to cool the biodiesel distillation thermal oil. According to the normal production process, crude biodiesel continues to flow out from the crude biodiesel outlet u of the crude biodiesel tank and is pumped to the crude methyl ester feed port a of the distillation tower through the crude biodiesel feed pump 13. After cooling the packing in the distillation tower 1 and the reboiler 2, the crude biodiesel after heat exchange has a temperature of about 230°C and flows from the heavy oil outlet e of the distillation tower into the heavy oil inlet g1 of the heavy oil cooler. After being water-cooled in the heavy oil cooler 4, the crude biodiesel flows out from the heavy oil outlet g2 of the heavy oil cooler. After coming out of the heavy oil cooler 4, the crude biodiesel flows to the heavy oil trough 5 again by gravity. The production process requires that the heat exchange area of the heavy oil cooler 4 is small. After cooling, the temperature of the crude biodiesel at this time is 150°C, which is still higher than the flash point temperature of crude biodiesel of 70°C. It is not suitable to return to the crude biodiesel tank 14 directly, but needs to be further cooled; when the crude biodiesel liquid level in the heavy oil trough 5 reaches half of the total liquid level, the heavy oil pump 6 is automatically started, and the crude biodiesel in the heavy oil trough 5 is pumped to the crude biodiesel cooler 20 through the heavy oil pump 6, and enters from the crude biodiesel inlet z of the crude biodiesel cooler. The temperature of the crude biodiesel tank 14 is set between 62 and 64°C, and the crude biodiesel begins to be cooled. The temperature control system 19 is started to automatically adjust the cooling water valve. After being water-cooled in the crude biodiesel cooler 20, the crude biodiesel flows out from the crude biodiesel outlet w of the crude biodiesel cooler, and then enters the shutdown cooling crude biodiesel reflux inlet r5 and flows back into the crude biodiesel tank 14. The temperature is cooled in this cycle. When the temperature of the heat transfer oil drops to 120°C and the temperature of the structured packing layer in the distillation tower 1 drops to 110°C, the crude biodiesel feed pump 13 is stopped. The biodiesel discharge pump 8 is started to pump the cold methyl ester with a temperature of ≤40°C in the biodiesel receiving tank 7 to the biodiesel outlet c of the distillation tower and enter the cooling packing. When cooling the packing of the distillation tower 1, pay attention to the temperature changes of each layer in the tower. Stop the biodiesel discharge pump 8 until the temperature of the packing layer of the distillation tower 1 is cooled to below 50°C and does not rebound.Open the nitrogen valve for breaking vacuum, and nitrogen enters from the vacuum outlet b of the distillation tower, and pay attention to the temperature change in the tower at all times. When the vacuum pressure in the system is slightly positive, close the nitrogen valve for breaking vacuum; open the steam inlet valve of the tower washing hot water tank 11, heat the water in the tower washing hot water tank 11 to 90°C, and then according to the normal production process, hot water flows out from the tower washing hot water tank outlet pipe p6, and is pumped to the distillation tower crude methyl ester feed port a in the middle of the distillation tower 1 through the tower washing hot water tank pump 12 to clean the packing in the distillation tower 1, and then start the high-temperature circulation pump 3 to circulate the hot water to clean the reboiler 2 tubes; the waste hot water after cleaning flows out from the distillation tower heavy oil outlet e and flows into the tower washing connection by gravity. The tower washing water feed pipe k is used for collecting the tower washing wastewater. After the tower washing wastewater from the shutdown and cooling stays in the tower washing receiving tank 9 for 36 hours, the wastewater is discharged from the tower washing receiving tank wastewater outlet pipe o at the cone bottom of the tower washing receiving tank 9 to the sewage station. When the sampling tube m of the tower washing receiving tank 9 samples and analyzes that the tower washing water contains oil, the water discharge is stopped and the waste oil is discharged from the oil outlet n of the tower washing receiving tank for production reuse. After the packing of the distillation tower 1 and the tubes of the reboiler 2 are cleaned, the hot water tank pump 12 of the tower washing tower is turned off, and the cooling water valve is opened to pump the cooling water to the biodiesel outlet c of the distillation tower to enter the cooling packing until the packing layer temperature cools to room temperature, to ensure that the packing will not spontaneously combust when the distillation tower 1 is repaired. The cooled wastewater exits the distillation tower's heavy oil outlet e and flows by gravity into the wash tower receiving tank's wash water feed pipe k. The wastewater is then discharged from the wash tower receiving tank's wastewater outlet pipe o to a sewage treatment station. During normal biodiesel production, the nitrogen inlet valve of the nitrogen supply device 15 at the top of the crude biodiesel tank 14 is opened. The oxygen content at the outlet of the nitrogen release valve is regularly analyzed and maintained within normal limits to ensure the safety of the crude biodiesel tank 14. If induced air charges accumulate around the crude biodiesel tank, the Tianmu-I direct lightning protection device monitors the situation in real time to prevent the crude biodiesel tank from being struck by lightning.

Claims

1. A biodiesel distillation production safety device, characterized by: The invention comprises a distillation tower (1), a reboiler (2), a high-temperature circulation pump (3), a heavy oil cooler (4), a heavy oil ground tank (5), a heavy oil pump (6), a biodiesel receiving tank (7), a biodiesel discharge pump (8), a tower washing receiving tank (9), a tower washing receiving tank pump (10), a tower washing hot water tank (11), a tower washing hot water tank pump (12), a crude biodiesel feed pump (13), a crude biodiesel tank (14), a nitrogen supply device (15), a breathing valve (16), a nitrogen release valve (17), a digital thermometer (18), a temperature control system (19), a crude biodiesel cooler (20) and a skylight lightning protection device; the temperature control system (19) comprises a digital thermometer with a temperature sensor (11), a temperature sensor (12), a temperature sensor (13), a temperature sensor (14), a temperature sensor (15), a temperature sensor (16), a temperature sensor (17), a temperature sensor (17), a temperature sensor (18 ... 8) a program control system PLC, a computer and an electric control cabinet, wherein the PLC is connected to the digital display thermometer (18) and the computer via a signal line; the distillation tower (1) is provided with a crude methyl ester feed port (a) in the middle, a distillation tower vacuum outlet (b) at the top, a distillation tower biodiesel outlet (c) at the middle and upper part, a reboiler vapor phase inlet (d) at the side of the middle and lower part, a distillation tower heavy oil outlet (e) at the bottom of the distillation tower, and a reboiler circulation port (f) at the center of the bottom of the distillation tower; the heavy oil cooler (4) is provided with a heavy oil inlet (g1) at the top, a heavy oil outlet (g2) at the bottom, and a heavy oil cooler cooling water outlet (h1) at the upper left part. , a heavy oil cooler cooling water inlet (h2) is provided at the lower left side; a heavy oil tank heavy oil inlet pipe (i1) is provided at the upper left side of the heavy oil tank (5), a heavy oil tank tail gas outlet pipe (i2) is provided at the upper right side, and a heavy oil tank heavy oil outlet (i3) is provided at the bottom; a biodiesel receiving tank biodiesel inlet pipe (j1) is provided at the upper left side of the biodiesel receiving tank (7), a biodiesel receiving tank tail gas outlet pipe (j2) is provided at the upper right side, and a biodiesel receiving tank biodiesel outlet (j3) is provided at the bottom; the lower part of the washing tower receiving tank (9) is in a cone shape, a washing tower receiving tank washing tower water feed pipe (k) is provided at the top center of the washing tower receiving tank near the edge, and a washing tower receiving tank washing tower water feed pipe (k) is provided at the top center of the washing tower receiving tank. A tower washing receiving tank tail gas outlet pipe (1) is provided; a sampling tube (m) is provided at the lower part of the side of the tower washing receiving tank, an oil discharge port (n) of the tower washing receiving tank is provided on the other side, and a tower washing receiving tank waste water outlet pipe (o) is provided at the conical bottom of the tower washing receiving tank; a tower washing hot water tank water feed pipe (p1) is provided near the edge of the top of the tower washing hot water tank (11), a tower washing hot water tank water vapor tail gas outlet pipe (p2) is provided at the center of the tank top, a steam heating coil is installed in the tower washing hot water tank tank, a tower washing hot water tank steam inlet pipe (p3) is provided at the lower part of one side of the hot water tank, and a tower washing hot water tank steam outlet pipe (p4) is provided at the lower part of the other side; a water temperature measuring tube (p5) is provided at the lower part of the side of the tower washing hot water tank, and a tower washing hot water tank outlet pipe (p6) is provided at the bottom of the tank;The lower part of the crude biodiesel tank (14) is in a cone shape, and a nitrogen-sealed nitrogen inlet (r1), a crude biodiesel inlet (r2), a nitrogen-sealed breathing valve outlet (r3), a nitrogen-sealed nitrogen release valve outlet (r4), and a shutdown cooling crude biodiesel reflux inlet (r5) are provided near the edge of the tank top. A crude biodiesel tank temperature measuring port (s) is provided at the lower middle part of one side of the crude biodiesel tank (14), and a digital thermometer (18) is installed at the crude biodiesel tank temperature measuring port (s). A crude biodiesel tank crude biodiesel outlet (u) is provided between the crude biodiesel tank temperature measuring port (s) and the cone connection. The crude biodiesel tank (14) is provided with a crude biodiesel outlet (u) at the same side and height as the bottom of the crude biodiesel inlet (r2). The crude biodiesel tank (14) is provided with an oil sampling port (t), and a glycerol separation outlet (v) is provided at the conical bottom of the crude biodiesel tank (14); the crude biodiesel cooler (20) is provided with a crude biodiesel cooler crude biodiesel outlet (w) at the top, a crude biodiesel cooler crude biodiesel inlet (z) at the bottom, a crude biodiesel cooler cooling water outlet (x) at the top left, and a crude biodiesel cooler cooling water inlet (y) at the bottom left; the skylight lightning protection device is provided around the crude biodiesel tank, and includes a lower device rod (22) and an upper skylight-Ⅰ type lightning protection component (21); the distillation tower heavy oil outlet (e) is divided into two paths, one of which is connected to the tower washing water feed pipe (k) of the tower washing receiving tank after passing through a valve. ), the oil discharge port (n) of the washing tower receiving tank and the wastewater outlet pipe (o) of the washing tower receiving tank are respectively merged after connecting the valve, and then connected to the washing tower receiving tank pump (10); the other route is connected to the heavy oil inlet (g1) of the heavy oil cooler after passing through the valve, the heavy oil outlet (g2) of the heavy oil cooler is connected to the heavy oil inlet pipe (i1) of the heavy oil trough, and the heavy oil outlet (i3) of the heavy oil trough is connected to the crude biodiesel inlet (z) of the crude biodiesel cooler after connecting to the heavy oil pump (6); the crude biodiesel outlet (w) of the crude biodiesel cooler is connected to the shutdown cooling crude biodiesel reflux inlet (r5) of the crude biodiesel tank (14), and the nitrogen supply device (15) is connected to the nitrogen blanketing nitrogen inlet (r1); The crude biodiesel outlet (u) of the crude biodiesel tank is connected to the inlet of the crude biodiesel feed pump (13), and the pipeline of the cooling water inlet (y) of the crude biodiesel cooler is provided with a temperature control system (19) connected to the signal line of the digital thermometer (18) provided at the temperature measuring port (s) of the crude biodiesel tank; the tower washing hot water tank outlet pipe (p6) is connected to the inlet of the tower washing hot water tank pump (12), and the outlet pipes of the tower washing hot water tank pump (12) and the crude biodiesel feed pump (13) are combined after connecting the valve and then connected to the crude methyl ester feed port (a) of the distillation tower; the reboiler circulation port (f) of the distillation tower is connected to the reboiler vapor phase inlet (d) of the distillation tower after being connected to the high-temperature circulation pump (3) and the reboiler (2) in sequence;The biodiesel outlet (c) of the distillation tower is connected to the biodiesel inlet pipe (j1) of the biodiesel receiving tank. The biodiesel outlet (j3) of the biodiesel receiving tank is connected to the product tank area after being connected to the biodiesel discharge pump (8). The biodiesel outlet (c) of the distillation tower is also connected to the cooling water pipe interface for cooling the tower.

2. The biodiesel distillation production safety device according to claim 1, characterized in that: The heavy oil outlet (e) of the distillation tower is located at the bottom of the distillation tower, 150 mm from the center line; the water temperature measuring tube (p5) is located at the lower side of the tower washing hot water tank, 400 mm from the bottom of the tank.

3. The biodiesel distillation production safety device according to claim 1, characterized in that: The bottom end of the inlet pipe of the crude biodiesel inlet (r2) is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part. The bottom of the pipe is 5.5 meters away from the tank top.

4. The biodiesel distillation production safety device according to claim 1, characterized in that: The bottom end of the inlet pipe of the shutdown cooling crude biodiesel reflux inlet (r5) is sealed, and four outlet holes with a diameter of 40 mm are evenly distributed around the lower part. The bottom of the pipe is 5.5 meters away from the tank top.

5. The biodiesel distillation production safety device according to claim 1, characterized in that: The protection range of the skylight lightning protection device is 70 degrees.

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