Laterite-nickel ore leaching flash tank-preheater heat exchange automatic allocation system

Abstract

Provided is a laterite-nickel ore leaching flash tank-preheater heat exchange automatic allocation system. The system comprises a preheating mechanism (1), a high-pressure kettle (2), a flash evaporation mechanism (3), a monitoring mechanism (4), and an allocation controller; the preheating mechanism (1) comprises a plurality of preheaters (11) which are sequentially connected in series; the flash evaporation mechanism (3) comprises a plurality of flash tanks (31) which are sequentially connected in series. The beneficial effects are: operation data of preheaters and flash tanks are detected in real time by means of the monitoring mechanism, and the allocation controller obtains optimal set pressures and optimal set temperatures of the flash tanks on the basis of the data detected by the monitoring mechanism, so that a temperature and pressure control system for the flash tanks can adjust the temperatures and pressures in the flash tanks to the optimal set temperatures and the optimal set pressures, thereby improving the heat exchange efficiency, and reducing the energy consumption and operation cost of a laterite-nickel ore high-pressure leaching process.

Description

A laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system Technical Field

[0001] The invention relates to the technical field of high-temperature leaching of laterite nickel ore, in particular to a laterite nickel ore leaching flash tank-preheater automatic heat exchange allocation system. Background Art

[0002] Due to its environmental advantages, hydrometallurgical processes are increasingly being used in the metallurgical field to replace pyrometallurgical processes. Hydrometallurgical processes mainly include atmospheric leaching and pressure leaching. The pressure leaching process generally involves first slurrying the ore, then preheating the slurry, and then subjecting the preheated slurry to pressure acid leaching in an autoclave. The slurry is then cooled and depressurized, neutralized, separated, and purified.

[0003] In traditional pressure leaching processes, a large amount of steam is required to preheat the slurry to the specified temperature before entering the autoclave. This consumes a large amount of heating steam, resulting in low heat utilization efficiency, long heating time, and high heating costs. On the other hand, after high-temperature and high-pressure leaching, the leachate needs to be gradually cooled and decompressed to low-temperature atmospheric pressure in a flash tank. This process generates a large amount of flash steam, which can be mixed with the feed slurry for preheating, fully utilizing the waste heat and reducing steam usage and operating costs.

[0004] However, existing multi-stage flash evaporation-preheating systems (such as those in Chinese Invention Patent Publication No. CN101899567A) are significantly affected by the flash tank feed slurry temperature and other operating parameters, resulting in high operating costs. In practice, these systems typically employ a fixed operating mode, rarely dynamically controlling the flash tank temperature and pressure based on specific operating parameters. This results in high operating costs.

[0005] Summary of the Invention

[0006] In view of this, it is necessary to provide a laterite nickel ore leaching flash tank-preheater automatic heat exchange adjustment system to solve the technical problem that the existing multi-stage flash evaporation-preheating system cannot dynamically control the flash tank temperature and flash tank pressure according to the operating parameter characteristics, resulting in high operating costs.

[0007] In order to achieve the above-mentioned object, the present invention provides a laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system, comprising a preheating mechanism, an autoclave, a flash mechanism, a monitoring mechanism and an allocation controller;

[0008] The preheating mechanism includes a plurality of preheaters connected in series, wherein the first medium inlet of the first preheater is used to introduce the slurry, and from the second preheater onwards, the first medium inlet of each preheater is connected to the first medium outlet of the previous preheater;

[0009] The material inlet of the autoclave is connected to the first medium outlet of the last preheater, and the steam inlet of the autoclave is provided with a steam injection regulating valve;

[0010] The flash evaporation mechanism includes a plurality of flash tanks connected in series, each flash tank corresponding to each preheater one by one, the material inlet of the first flash tank being connected to the material outlet of the autoclave, and the material inlet of each flash tank from the second flash tank onwards being connected to the material outlet of the previous flash tank, and the steam outlet of each flash tank being connected to the second medium inlet of the corresponding preheater;

[0011] The monitoring mechanism is used to monitor the temperature of the slurry in each preheater, the temperature of the steam introduced into the second medium inlet of each preheater, the pressure in each flash tank, the flow rate and temperature of the leachate entering the material inlet of each flash tank, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank;

[0012] The deployment controller is electrically connected to the monitoring mechanism and each of the flash tanks, and is used to obtain the optimal set pressure and the optimal set temperature of each of the flash tanks based on the monitoring data obtained by the monitoring mechanism.

[0013] In some embodiments, the monitoring mechanism includes a slurry injection flow meter, a slurry injection thermometer, a flash evaporation feed flow meter, a flash evaporation feed thermometer, and a flash evaporation discharge flow meter;

[0014] The first medium inlet of the first preheater is provided with the slurry injection flowmeter and the slurry injection thermometer; the second medium inlet of each preheater is provided with a preheating steam thermometer;

[0015] The material inlet of the first flash tank is provided with the flash feed flow meter and the flash feed thermometer, and the material outlet of each flash tank is provided with the flash discharge flow meter;

[0016] Each of the flash tanks is provided with a flash tank pressure detection component.

[0017] In some embodiments, the following formula is used to solve the optimal set pressure and optimal set temperature of each flash tank: WL j-1 H j-1 =WL j H j +(WL j-1 -WL j )H vj (1)

[0018] Where, j represents the number of flash tanks, WL j-1 and WL jRespectively represent the leachate flow rate of the flash tank of the j-1th and jth stages, which can be obtained through the flash discharge flow meter, H j-1 and H j represent the enthalpy values ​​of the flash tank leachate at the j-1 and jth stages, respectively, H vj represents the enthalpy of the j-th stage flash steam; W i蒸汽入 =WL 3-j -WL 4-j (4)

[0019] Wherein, WS represents the slurry flow rate that needs to be preheated, which can be obtained by the slurry injection flow meter, C p Represents the heat capacity of the slurry, which is an empirical value, U i and A i The heat transfer coefficient and heat transfer area of ​​the i-th stage preheating tower, T i+1 and T i Represents the slurry temperature in the i+1th and ith stage preheaters respectively, which can be obtained by the slurry injection thermometer, T i蒸汽入 and T i蒸汽出 represent the temperature of steam entering and leaving the i-th stage preheater, T i蒸汽入 It can be obtained by preheating steam thermometer, k is the contact coefficient between slurry and steam, r i represents the feed pipe radius of the i-th stage preheater, W i蒸汽入 is the steam flow rate entering the i-th stage preheater;

[0020] K j is the gas phase fraction in the flash tank, where are the vapor and liquid fugacity coefficients under the j-th stage flash operation conditions, respectively. For pure components, they are only related to the temperature and pressure of the substance and can be calculated by querying the physical property database or using formulas (6) and (7). WL j-1 =WL j ×(1-K j ) (8)

[0021] Among them, P j is the optimal set pressure of the j-stage flash tank, T j is the optimal set temperature of the j-th stage flash tank, is the steam volume in the j-th flash tank, R is the gas constant, is the liquid at standard pressure P s The fugacity below is the volume of liquid in the j-th stage flash tank;

[0022] The system constraint equations include equations (9) and (10): WL3=W defined (9) T i蒸汽出 -T i =ΔT best (10)

[0023] Among them, W defined is the custom leachate flow rate, ΔT best is the optimized pinch point temperature.

[0024] Solving equations (1)-(8) under the condition of satisfying the constraint equations can obtain the optimal set pressure P of each flash tank. j And the optimal setting temperature T j .

[0025] In some embodiments, the optimized pinch temperature ΔT best is 10℃.

[0026] In some embodiments, the preheating mechanism further includes a feed pipe connected to the first medium inlet of the first preheater.

[0027] In some embodiments, starting from the second preheater, the first medium inlet of each preheater is connected to the first medium outlet of the previous preheater through a first connecting pipe.

[0028] In some embodiments, the steam inlet of the autoclave is connected to a steam input pipe, and the steam input pipe is provided with the steam injection regulating valve.

[0029] In some embodiments, the material inlet of the first flash tank is connected to the material outlet of the autoclave through a leaching slurry pipe.

[0030] In some embodiments, starting from the second flash tank, the material inlet of each flash tank is connected to the material outlet of the previous flash tank through a material outlet pipe.

[0031] In some embodiments, the steam outlet of each flash tank is connected to the second medium inlet of the corresponding preheater through a second connecting pipe.

[0032] In some embodiments, the deployment controller is also used to send the optimal set pressure and optimal set temperature of each flash tank to the corresponding temperature and pressure control module of the flash tank based on the obtained optimal set pressure and optimal set temperature of each flash tank, so that the temperature and pressure in each flash tank reach the optimal set pressure and optimal set temperature.

[0033] Compared with the prior art, the technical solution proposed in the present invention has the following beneficial effects: the temperature of the slurry in each preheater, the temperature of the steam introduced into the second medium inlet of each preheater, the pressure in each flash tank, the flow rate and temperature of the leachate entering the material inlet of each flash tank, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank are monitored in real time by a monitoring mechanism; the adjustment controller obtains the optimal set pressure and optimal set temperature of each flash tank based on the monitoring data obtained by the monitoring mechanism, thereby facilitating the temperature and pressure control module of the flash tank to adjust the temperature and pressure in the flash tank to the optimal set temperature and optimal set pressure, thereby improving the heat exchange efficiency and further reducing the energy consumption and operating cost of the high-pressure leaching process of laterite nickel ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic structural diagram of an embodiment of a laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system provided by the present invention;

[0035] Figure 2 is the pinch point calculation model;

[0036] In the figure: 1-preheating mechanism, 11-preheater, 12-feed pipe, 13-first connecting pipe, 2-autoclave, 21-steam injection regulating valve, 22-steam input pipe, 23-leaching slurry pipe, 3-flash evaporation mechanism, 31-flash tank, 32-material outlet pipe, 33-second connecting pipe, 4-monitoring mechanism, 41-slurry injection flowmeter, 42-slurry injection thermometer, 43-flash feed flowmeter, 44-flash feed thermometer, 46-flash discharge flowmeter, 48-preheating steam thermometer. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0038] 1 , the present invention provides a laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system, comprising a preheating mechanism 1, an autoclave 2, a flash mechanism 3, a monitoring mechanism 4 and an allocation controller;

[0039] The preheating mechanism 1 includes a plurality of preheaters 11 connected in series, wherein the first medium inlet of the first preheater 11 is used to introduce the slurry, and from the second preheater 11 onwards, the first medium inlet of each preheater 11 is connected to the first medium outlet of the previous preheater 11;

[0040] The material inlet of the autoclave 2 is connected to the first medium outlet of the last preheater 11, and the steam inlet of the autoclave 2 is provided with a steam injection regulating valve 21;

[0041] The flash evaporation mechanism 3 includes a plurality of flash tanks 31 connected in series, each flash tank 31 corresponding to each preheater 11. The material inlet of the first flash tank 31 is connected to the material outlet of the autoclave 2. From the second flash tank 31 onwards, the material inlet of each flash tank 31 is connected to the material outlet of the previous flash tank 31. The steam outlet of each flash tank 31 is connected to the second medium inlet of the corresponding preheater 11.

[0042] The monitoring mechanism 4 is used to monitor the temperature of the slurry in each preheater 11, the temperature of the steam introduced into the second medium inlet of each preheater 11, the pressure in each flash tank 31, the flow rate and temperature of the leachate entering the material inlet of each flash tank 31, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank 31;

[0043] The deployment controller is electrically connected to the monitoring mechanism 4 and each of the flash tanks 31 , and is used to obtain the optimal set pressure and the optimal set temperature of each of the flash tanks 31 based on the monitoring data obtained by the monitoring mechanism 4 .

[0044] During use, the ore pulp is first passed into the first preheater 11, where steam is used to heat the ore pulp to a first preheating temperature. Next, steam is used to heat the ore pulp heated to the first preheating temperature to a second preheating temperature. Next, steam is used to heat the ore pulp heated to the second preheating temperature to a third preheating temperature. The third preheating temperature is the desired predetermined preheating temperature. Leaching then proceeds, where the ore pulp, heated to the desired preheating temperature in stages, is transferred to the autoclave 2. The regulating valve 21 is opened, steam is introduced into the autoclave 2, and the ore pulp is subjected to high-pressure acid leaching using sulfuric acid at a predetermined leaching pressure and temperature to obtain a leached slurry. The predetermined leaching pressure and temperature can be determined based on the specific ore. Next, a cooling and pressure reduction step is performed, where the leached slurry is cooled and pressure-reduced by flash evaporation, for example, also in a staged manner. For example, similar to the three-stage heating method, a three-stage cooling and pressure reduction method can be employed. First, the leachate is cooled to a first temperature and a first pressure; then, the leachate, having been cooled to the first temperature and the first pressure, is cooled to a second temperature and a second pressure; and finally, the leachate, having been cooled to the second temperature and the second pressure, is cooled to a third temperature and a third pressure. The third temperature and the third pressure are suitable for the subsequent neutralization. Flash evaporation is used to reduce the temperature and pressure of the leachate to a predetermined temperature, simultaneously generating steam. This steam can be recycled to heat the slurry to the desired preheating temperature. For example, the steam generated by cooling the leachate to the third temperature and the third pressure is used to heat the slurry to the first preheating temperature; the steam generated by cooling the leachate to the second temperature and the second pressure is used to heat the slurry to the second preheating temperature; and the steam generated by cooling the leachate to the first temperature and the first pressure is used to heat the slurry to the third preheating temperature. This recycles energy, reduces waste, and lowers costs. Finally, the cooled and depressurized leaching slurry is neutralized, for example, with limestone, to a desired pH. The leaching slurry is then separated to produce a leach residue and a leachate, which is then purified. Since the neutralization, separation, and purification steps are well-known processes in the pressure leaching process and readily understood by those skilled in the art, they will not be described in detail here.

[0045] The flash tank-preheater heat exchange automatic adjustment process is as follows: the monitoring device 4 monitors in real time the temperature of the slurry in each preheater 11, the temperature of the steam introduced into the second medium inlet of each preheater 11, the pressure in each flash tank 31, the flow rate and temperature of the leachate entering the material inlet of each flash tank 31, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank 31; the adjustment controller obtains the optimal set pressure and optimal set temperature of each flash tank based on the monitoring data obtained by the monitoring device, so that the temperature and pressure control module of the flash tank can adjust the temperature and pressure in the flash tank to the optimal set temperature and optimal set pressure, thereby improving the heat exchange efficiency and further reducing the energy consumption and operating costs of the laterite nickel ore high-pressure leaching process.

[0046] In order to specifically realize the function of the monitoring mechanism 4, please refer to FIG1 . In a preferred embodiment, the monitoring mechanism 4 includes a slurry injection flowmeter 41, a slurry injection thermometer 42, a flash evaporation feed flowmeter 43, a flash evaporation feed thermometer 44, and a flash evaporation discharge flowmeter 46.

[0047] The first medium inlet of the first preheater 11 is provided with the slurry injection flowmeter 41 and the slurry injection thermometer 42; the second medium inlet of each preheater 11 is provided with a preheating steam thermometer 48;

[0048] The material inlet of the first flash tank 31 is provided with the flash feed flowmeter 43 and the flash feed thermometer 44 , and the material outlet of each flash tank 31 is provided with the flash discharge flowmeter 46 .

[0049] In order to specifically solve the optimal set pressure and the optimal set temperature of each flash tank 31, please refer to Figure 1. In a preferred embodiment, the following formula is used to solve the optimal set pressure and the optimal set temperature of each flash tank 31: WL j-1 H j-1 =WL j H j +(WL j-1 -WL j )H vj (1)

[0050] Where j represents the number of flash tanks, WL j-1 and WL j Respectively represent the leachate flow rate of the flash tank of the j-1th and jth stages, which can be obtained through the flash discharge flow meter, H j-1 and H j represent the enthalpy values ​​of the flash tank leachate at the j-1 and jth stages, respectively, H vj represents the enthalpy of the j-th stage flash steam; Wi蒸汽入 =WL 3-j -WL 4-j (4)

[0051] Wherein, WS represents the slurry flow rate that needs to be preheated, which can be obtained by the slurry injection flow meter, C p Represents the heat capacity of the slurry, which is an empirical value, U i and A i The heat transfer coefficient and heat transfer area of ​​the i-th stage preheating tower, T i+1 and T i Represents the slurry temperature in the i+1th and ith stage preheaters respectively, which can be obtained by the slurry injection thermometer, T i蒸汽入 and T i蒸汽出 represent the temperature of steam entering and leaving the i-th stage preheater, T i蒸汽入 It can be obtained by preheating steam thermometer, k is the contact coefficient between slurry and steam, r i represents the feed pipe radius of the i-th stage preheater, W i蒸汽入 is the steam flow rate entering the i-th stage preheater;

[0052] K j is the gas phase fraction in the flash tank, where are the vapor and liquid fugacity coefficients under the j-th stage flash operation conditions, respectively. For pure components, they are only related to the temperature and pressure of the substance and can be calculated by querying the physical property database or using formulas (6) and (7). WL j-1 =WL j ×(1-K j ) (8)

[0053] Among them, P j is the optimal set pressure of the j-stage flash tank, T j is the optimal set temperature of the j-th stage flash tank, is the steam volume in the j-th flash tank, R is the gas constant, is the liquid at standard pressure P s The fugacity below is the volume of liquid in the j-th stage flash tank;

[0054] The system constraint equations include equations (9) and (10): WL3=W defined (9) T i蒸汽出 -T i =ΔT best (10)

[0055] Among them, W defined is the custom leachate flow rate, ΔTbest is the optimized pinch point temperature.

[0056] Under the condition of satisfying the constraint equations (9) and (10), the optimal set pressure P of each flash tank can be obtained by solving equations (1)-(8). j And the optimal setting temperature T j .

[0057] In order to determine the optimized pinch point temperature, please refer to FIG1 . In a preferred embodiment, the optimized pinch point temperature ΔT best is 10℃.

[0058] The specific determination process is as follows:

[0059] Importing stream information into the pinch calculation model. An economic evaluation of the minimum heat transfer temperature difference yields a total cost-temperature difference curve, as shown in Figure 2. Figure 2 shows that costs decrease with increasing minimum heat transfer temperature differences, and continue to decrease as the minimum heat transfer temperature difference increases. Considering that smaller heat transfer temperature differences require larger heat exchange areas and higher equipment investment costs, a minimum heat transfer temperature difference of 10°C is selected for the laterite nickel ore flash-preheating process, i.e., the pinch point between the cold and hot streams. This pinch point temperature is input into the parameter calculation model to calculate the operating conditions for each of the three flash tanks.

[0060] In order to specifically realize the flow of material into the first medium inlet of the first preheater 11 , please refer to FIG. 1 . In a preferred embodiment, the preheating mechanism 1 further includes a feed pipe 12 , which is connected to the first medium inlet of the first preheater 11 .

[0061] In order to specifically realize the communication between the first medium inlet of each preheater 11 and the first medium outlet of the previous preheater 11, please refer to Figure 1. In a preferred embodiment, starting from the second preheater 11, the first medium inlet of each preheater 11 is connected to the first medium outlet of the previous preheater 11 through a first connecting pipe 13.

[0062] In order to facilitate the input of high-temperature steam into the autoclave 2 , referring to FIG. 1 , in a preferred embodiment, the steam inlet of the autoclave 2 is connected to a steam input pipe 22 , and the steam input pipe 22 is provided with the steam injection regulating valve 21 .

[0063] In order to specifically realize the communication between the material inlet of the first flash tank 31 and the material outlet of the autoclave 2 , please refer to FIG. 1 . In a preferred embodiment, the material inlet of the first flash tank 31 and the material outlet of the autoclave 2 are communicated through a leaching slurry pipe 23 .

[0064] In order to specifically realize the communication between the material inlet of each flash tank 31 and the material outlet of the previous flash tank 31 , please refer to Figure 1 . In a preferred embodiment, starting from the second flash tank 31 , the material inlet of each flash tank 31 is connected to the material outlet of the previous flash tank 31 through the material outlet pipe 32 .

[0065] In order to specifically realize the connection between the steam outlet of each flash tank 31 and the second medium inlet of the corresponding preheater 11, please refer to Figure 1. In a preferred embodiment, the steam outlet of each flash tank 31 is connected to the second medium inlet of the corresponding preheater 11 through a second connecting pipe 33.

[0066] In order to facilitate the automatic adjustment of the temperature and pressure of each flash tank to the optimal set temperature and the optimal set temperature, please refer to Figure 1. In a preferred embodiment, the deployment controller is also used to send the optimal set pressure and the optimal set temperature of each flash tank to the corresponding temperature and pressure control module of the flash tank based on the obtained optimal set pressure and the optimal set temperature of each flash tank, so that the temperature and pressure in each flash tank reach the optimal set pressure and the optimal set temperature. It should be understood that existing flash tanks all have the function of setting pressure and temperature. When the temperature and pressure control module of the flash tank obtains the set temperature and set pressure, it can automatically make the temperature and pressure in the flash tank reach the set value by controlling the feed flow, discharge flow, steam output flow of the flash tank, opening the pressure relief valve, etc. This is the existing technology and will not be described in detail. To better understand the present invention, the working process of the flash tank-preheater automatic heat exchange adjustment system for laterite nickel ore leaching provided by the present invention is described in detail below with reference to Figures 1 and 2: The flash tank-preheater automatic heat exchange adjustment process is as follows: the monitoring mechanism 4 monitors in real time the temperature of the slurry in each preheater 11, the temperature of the steam introduced into the second medium inlet of each preheater 11, the pressure in each flash tank 31, the flow rate and temperature of the leachate entering the material inlet of each flash tank 31, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank 31; the adjustment controller obtains the optimal set pressure and optimal set temperature of each flash tank based on the monitoring data obtained by the monitoring mechanism, and sends the optimal set pressure and optimal set temperature of each flash tank to the temperature and pressure control module of the corresponding flash tank, so that the temperature and pressure in each flash tank reach the optimal set pressure and optimal set temperature. This improves the heat exchange efficiency and further reduces the energy consumption and operating cost of the laterite nickel ore high-pressure leaching process. The operating conditions, heat transfer efficiency and energy consumption after adopting the above-mentioned flash evaporation-preheating heat exchange automatic optimization system are shown in Table 1.

[0067] Table 1 Operating conditions, heat transfer efficiency and energy consumption before and after the flash evaporation-preheating heat exchange automatic optimization system is adopted

[0068] It can be seen that the flash evaporation-preheating automatic optimization and allocation system can increase the logistics temperature of the three-stage preheating outlet from 159.7°C to 174.1°C, optimize the heat exchange effect, and reduce the system energy consumption from 7.14Gcal / h to 6.24Gcal / h. It shows that the flash evaporation-preheating automatic optimization and allocation system provided by the present invention can improve the heat exchange efficiency and further reduce the energy consumption and operating costs of the laterite nickel ore high-pressure leaching process. The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A laterite nickel ore leaching flash tank-preheater heat exchange automatic deployment system, characterized in that: It includes a preheating mechanism, an autoclave, a flash evaporation mechanism, a monitoring mechanism and a dispensing controller; The preheating mechanism comprises a plurality of preheaters connected in series, wherein the first medium inlet of the first preheater is used to introduce the slurry, and starting from the second preheater, the first medium inlet of each preheater is connected to the first medium outlet of the previous preheater; The material inlet of the autoclave is connected to the first medium outlet of the last preheater, and the steam inlet of the autoclave is provided with a steam injection regulating valve; The flash mechanism comprises a plurality of flash tanks connected in series, each flash tank corresponds to each preheater one by one, the material inlet of the first flash tank is connected to the material outlet of the autoclave, and starting from the second flash tank, the material inlet of each flash tank is connected to the material outlet of the previous flash tank, and the steam outlet of each flash tank is connected to the second medium inlet of the corresponding preheater; The monitoring mechanism is used to monitor the temperature of the slurry in each preheater, the temperature of the steam introduced into the second medium inlet of each preheater, the pressure in each flash tank, the flow rate and temperature of the leachate entering the material inlet of each flash tank, and the flow rate and temperature of the leachate discharged from the material outlet of each flash tank; The deployment controller is electrically connected to the monitoring mechanism and each of the flash tanks, and is used to obtain the optimal set pressure and the optimal set temperature of each of the flash tanks based on the monitoring data obtained by the monitoring mechanism.

2. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: The monitoring mechanism includes a slurry injection flowmeter, a slurry injection thermometer, a flash evaporation feed flowmeter, a flash evaporation feed thermometer and a flash evaporation discharge flowmeter; The first medium inlet of the first preheater is provided with the slurry injection flowmeter and the slurry injection thermometer; the second medium inlet of each preheater is provided with a preheating steam thermometer; The material inlet of the first flash tank is provided with the flash feed flow meter and the flash feed Thermometer, the material outlet of each flash tank is provided with the flash discharge flow meter; The flash tank pressure detection component is arranged in each of the flash tanks.

3. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 2, characterized in that: The following formula is used to solve the optimal set pressure and optimal set temperature of each flash tank: WL j-1 H j-1 =WL j H j +(WL j-1 -WL j )H vj (1) Where j represents the number of flash tanks, WL j-1 and WL j represents the leachate flow rate of the flash tank of the j-1th and jth stages respectively, which can be obtained through each of the flash discharge flow meters, H j-1 and H j represent the enthalpy of the flash tank leachate of the j-1st and jth stages, H vj represents the enthalpy of the j-th flash steam; W i蒸汽入 =WL 3-j -WL 4-j (4) Wherein, WS represents the slurry flow rate that needs to be preheated, which can be obtained by the slurry injection flow meter, C p Represents the heat capacity of the slurry, which is an empirical value, U i and A i The heat transfer coefficient and heat transfer area of ​​the i-th stage preheating tower, T i+1 and T i Represents the slurry temperature in the i+1th and ith stage preheaters respectively, which can be obtained by the slurry injection thermometer, T i蒸汽入 and T i蒸汽出 represent the temperatures of the steam entering and leaving the i-th stage preheater, T i蒸汽入 It can be obtained by preheating steam thermometer, k is the contact coefficient between slurry and steam, r i represents the feed pipe radius of the i-th stage preheater, W i蒸汽入 is the steam flow rate entering the i-th stage preheater; K j is the gas phase fraction in the flash tank, where Under the j-th flash operation conditions, The vapor and liquid fugacity coefficients are only related to the temperature and pressure of the substance for pure components and can be calculated by querying the physical property database or using equations (6) and (7). WL j-1 =WL j ×(1-K j ) (8) Among them, P j is the optimal set pressure of the j-th flash tank, T j is the optimal set temperature of the j-th flash tank, is the steam volume in the j-th flash tank, R is the gas constant, f i s is the liquid at standard pressure P s The fugacity below is the volume of liquid in the j-th flash tank; The system constraint equations include equation (9) and equation (10): <h2 style=";text-align:left;direction:ltr">WL3=W<h2 style=";text-align:left;direction:ltr"> defined <h2 style=";text-align:left;direction:ltr"> (9) T i蒸汽出 -T i =ΔT best (10) Among them, W defined is the custom leachate flow rate, ΔT best is the optimized pinch point temperature. Under the condition of satisfying the constraint equation, solving equations (1)-(8) can obtain the optimal set pressure P of each flash tank. j And the best setting temperature T j .

4. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 3, characterized in that: Optimized pinch point temperature ΔT best is 10℃.

5. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: The preheating mechanism further comprises a feed pipe, which is communicated with a first medium inlet of the first preheater.

6. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: Starting from the second preheater, the first medium inlet of each preheater is connected with the first medium outlet of the previous preheater through the first connecting pipe.

7. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: The steam inlet of the autoclave is connected to a steam input pipe, and the steam injection regulating valve is arranged on the steam input pipe.

8. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: The material inlet of the first flash tank is communicated with the material outlet of the autoclave through a leaching slurry pipe.

9. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: Starting from the second flash tank, the material inlet of each flash tank is connected with the material outlet of the previous flash tank through the material outlet pipe.

10. The laterite nickel ore leaching flash tank-preheater heat exchange automatic allocation system according to claim 1, characterized in that: The steam outlet of each flash tank is connected to the second medium inlet of the corresponding preheater through a second connecting pipe.

11. The laterite nickel ore leaching flash tank-preheater automatic heat exchange allocation system according to claim 1, characterized in that: The deployment controller is also used to send the optimal set pressure and optimal set temperature of each flash tank to the corresponding temperature and pressure control module of the flash tank according to the obtained optimal set pressure and optimal set temperature of each flash tank, so that the temperature and pressure in each flash tank reach the optimal set pressure and optimal set temperature.

Images