阅读说明：本技术 适用于炼油常减压装置的多元组分分离系统 (Suitable for refining oil the multicomponent mixture separation system of atmospheric and vacuum distillation unit ) 是由 金浩哲 童轶之 王超 于 2019-08-20 设计创作，主要内容包括：本发明公开了一种适用于炼油常减压装置的多元组分分离系统。包括监控部分、原油入口部分、电脱盐罐部分和原油出口部分；在电脱盐罐顶部内侧和底部外侧分别对装有射线发射器和射线探测器；利用射线衰减原理来对电脱盐罐内轻组分、乳化层、重组分的厚度实时监测和计算求解；基于厚度监测结果,若超过设定阈值,通过上位机调节开度,使得各组分层的厚度精准控制在某一既定范围,并实现实时动态的多元组分精准分离。本发明能用于轻组分、乳化层和重组分厚度的精准监测和检测,通过破乳剂的自动注入使乳化层充分分离,能最大限度规避人为因素的影响,提升了轻、重组分分离的效率。(The multicomponent mixture separation system that the invention discloses a kind of suitable for refining oil atmospheric and vacuum distillation unit.Including monitor portion, crude oil intake section, electrical desalter part and crude exports part；In electrical desalter inside top and bottom outside respectively to equipped with ray emitter and ray detector；Light component, emulsion layer, the thickness real-time monitoring of heavy constituent and calculating in electrical desalter are solved using ray attenuation principle；Based on thickness monitor as a result, adjusting aperture by host computer if being more than given threshold, so that the thickness of each group layering is precisely controlled in a certain given area, and realize that dynamic multicomponent mixture precisely separates in real time.The present invention can be used for the accurate monitoring and detection of light component, emulsion layer and heavy constituent thickness, be sufficiently separated emulsion layer by being automatically injected for demulsifier, can evade the influence of human factor to greatest extent, improve the efficiency of light heavy constituent separation.)

1. a kind of multicomponent mixture separation system suitable for refining oil atmospheric and vacuum distillation unit, which is characterized in that including electrical desalter (13) And monitor portion (1), crude oil intake section (2), electrical desalter part (3) and crude exports part (4)；

The monitor portion (1) includes pressure sensor (5), the first ray emitter (601), the second ray emitter (602), third ray emitter (603), the first ray detector (2301), the second ray detector (2302), third ray Detector (2303), 485 bus of RS (15), host computer (16)；First ray emitter (601), the second ray emitter (602), third ray emitter (603) is equidistantly horizontally arranged at electrical desalter (13) top inner wall leftward position, and first penetrates It is de- that line detector (2301), the second ray detector (2302), third ray detector (2303) are equidistantly horizontally arranged at electricity Salt cellar (13) bottom outer wall leftward position, the first ray detector (2301), the second ray detector (2302), third ray are visited It is right with the first ray emitter (601), the second ray emitter (602), third ray emitter (603) respectively to survey device (2303) It should be arranged in opposite directions on same vertical direction；Pressure sensor (5) is mounted on the electro-desalting on the right side of third ray emitter (603) Tank (13) top inner wall；Pressure sensor (5) and three ray emitters (601,602,603), three ray detectors (2301,2302,2303) it is communicated to connect by RS485 bus (15) and host computer (16)；

The electrical desalter part (3) includes de- preceding crude oil entrance (7), recombination sub-export (20) and inflating port (21)；Electricity is de- Salt cellar (13) bottom offers de- preceding crude oil entrance (7) between two parties, and electrical desalter (13) bottom side offers recombination sub-export (20), recombination sub-export (20) is located on the right side of de- preceding crude oil entrance (7), offers de- rear crude oil at the top of electrical desalter (13) between two parties It exports (14)；Electrical desalter (13) top side offers inflating port (21), and inflating port (21) is located at de- rear crude exports (14) Right side；Inflating port (21) is connected through the 6th valve (1906) with compressor (1805) entrance；

The crude oil intake section (2) includes mixer (17), the first pump (1801), the second pump (1802), third pump (1803), the first valve (1901), the second valve (1902), third valve (1903) and the 4th valve (1904)；First pump (1801) entrance and demulsifier inlet connection, the first pump (1801) outlet are connected to mixer (17) through the first valve (1901) Input terminal；Second pump (1802) entrance and crude oil feeding mouth connection, the second pump (1802) outlet are connected through the second valve (1902) To mixer (17) input terminal；Third pumps (1803) one end and recombination sub-export (20) connection, and the other end is through the 4th valve (1904) it is connected to the input terminal of mixer (17)；The output end of mixer (17) is by third valve (1903) connection before de- Crude oil entrance (7)；Wherein demulsifier is pumped into mixer (17) by the first pump (1801) through the first valve (1901), and crude oil is logical It crosses the second pump (1802) and is pumped into mixer (17) through the second valve (1902)；Heavy constituent positioned at electrical desalter (13) middle and lower part Mixer (17) are pumped into through the 4th valve (1904) after recombination sub-export (20) is by third pump (1803) extraction；Demulsifier, Crude oil and a part of heavy constituent (9) of extraction be sufficiently mixed in mixer (17) after successively through third valve (1903), it is de- before Crude oil entrance (7) enters electrical desalter (13)；

The crude exports part (4) includes float (11) and the 4th pump (1804)；Float (11) floating with floater shot In light component (8) surface in electrical desalter (13), the bottom input port of float (11) structure is deep into the liquid level of light component (8) Under, the delivery outlet of float (11) is connected to de- rear crude exports (14) by hose (22)；Crude exports (14) successively pass through after de- 5th valve (1905) and the 4th pump (1804) connection, so that light component (8) pumps out electrical desalter (13) through the 4th pump (1804).

2. the multicomponent mixture separation system according to claim 1 for being suitable for refining oil atmospheric and vacuum distillation unit, it is characterised in that: institute The first valve (1901), the second valve (1902), third valve (1903), the 4th valve (1904), the 5th valve stated (1905) host computer (16) are connected to through RS485 bus (15)；The host computer (16) of monitor portion (1) passes through RS485 bus (15) control signal is sent to each valve (1901,1902,1903,1904,1905) independent control to each valve.

3. the multicomponent mixture separation system according to claim 1 for being suitable for refining oil atmospheric and vacuum distillation unit, it is characterised in that: institute In the monitor portion (1) stated, the first ray emitter (601), the second ray emitter (602), third ray emitter (603) The ray of different frequency is issued, and adjusts ray frequency according to the difference of the interior multicomponent mixture property of electrical desalter (13) is respectively independent Rate.

4. the multicomponent mixture separation system according to claim 1 for being suitable for refining oil atmospheric and vacuum distillation unit, it is characterised in that: institute In the crude exports part (4) stated, filter screen (12) are installed between the 5th valve (1905) and the 4th pump (1804).

5. the multicomponent mixture separation system according to claim 1 for being suitable for refining oil atmospheric and vacuum distillation unit, it is characterised in that: nitrogen Gas is passed into electrical desalter (13) from compressor (1805) through the 6th valve (1906).

Technical field

The present invention relates to petroleum refining industry's atmospheric and vacuum distillation unit Crude Desalting Systems, have particularly related to a kind of suitable for oil refining The multicomponent mixture separation system of atmospheric and vacuum distillation unit.

Background technique

In petrochemical industry, electro-desalting be control atmospheric and vacuum distillation unit corrosion the first line of defence, the purpose is to remove water, Salt (chloride), solid and other impurity into crude oil, to reduce the scaling in follow-up process, operation fluctuation And the corrosion risk of process equipment, promote safe operation maintenance levels.In recent years, with the height of China's import middle-eastern crude Sulphur, contains chlorine and heaviness at peracid, and the de-salting operation of electrical desalter is substantially carried out by experience, and one side desalting effect is bad, separately On the one hand removing of the aqueous qualification rate of saliferous lower than technical requirement, especially chloride ion of de- rear crude oil, which is not thorough, directly leads Cause the process pipe, heat exchanger, air cooler of Atmospheric vacuum system that dew point corrosion, NH occurs₄Cl and NH₄HS crystal corrosion, multiphase flow punching The failure such as erosion, brings the stable operation of atmospheric and vacuum distillation unit, equipment anticorrosion, product quality and seriously affects, while giving downstream process The Process anti-corrosion of device, safe O&M increase difficulty.

Currently, alleviating and reducing in atmospheric and vacuum distillation unit using modes such as water filling, note corrosion inhibiter, note neutralizers in oil refining enterprise The corrosion risk of equipment achieves certain effect, however these measures solve the etching problem of ammonium salt not from source, special It is not NH₄The etching problem of Cl.In recent years, petroleum chemical enterprise occur because atmospheric tower, Top of Vacuum Tower follow pipeline, heat exchanger, air-cooled The major accidents such as fire, explosion caused by device corrosion etc. are substantially related to ammonium salt crystallization corrosion, cause great economy damage It becomes estranged undesirable social influence.Therefore, for the status of current atmospheric and vacuum distillation unit electric desalting technology, oil refining enterprise needs a kind of energy Enough realize the system that efficiently separates of atmospheric and vacuum distillation unit electrical desalter weight component, light component in real-time monitoring electrical desalter, again The thickness of component and emulsion layer promotes the de- of chloride ion so as to which more precise control is light, the separation of heavy constituent to greatest extent Except effect, the security and stability of atmospheric and vacuum distillation unit is improved.

Summary of the invention

It is not easy to monitor in order to effectively solve light component in Atmospheric vacuum electrical desalter, heavy constituent and emulsion layer thickness, from Dynamicization is horizontal low, and weight component separates insufficient problem, and the present invention proposes a kind of suitable for refining oil the polynary of atmospheric and vacuum distillation unit Component separation system, which can be accurately detected the thickness of weight component and each layer of emulsion layer in electrical desalter, and realize Dynamic multicomponent mixture precisely separates in real time.

In order to achieve the above object of the invention, the technical solution adopted by the present invention is that:

Multicomponent mixture separation system include electrical desalter and monitor portion, crude oil intake section, electrical desalter part and Crude exports part.

The monitor portion includes pressure sensor, the first ray emitter, the second ray emitter, third ray hair Emitter, the first ray detector, the second ray detector, third ray detector, RS485 bus, host computer；First ray hair Emitter, the second ray emitter, third ray emitter are equidistantly horizontally arranged at electrical desalter top inner wall leftward position, the It is left that one ray detector, the second ray detector, third ray detector are equidistantly horizontally arranged at electrical desalter bottom outer wall Side position, the first ray detector, the second ray detector, third ray detector respectively with the first ray emitter, second Ray emitter, third ray emitter correspondence are arranged in opposite directions on same vertical direction；Pressure sensor is mounted on third and penetrates Electrical desalter top inner wall on the right side of line transmitter；Pressure sensor and three ray emitters, three ray detectors pass through RS485 bus and host computer communicate to connect.

The electrical desalter part includes de- preceding crude oil entrance, recombination sub-export and inflating port；Electrical desalter bottom occupies In offer it is de- before crude oil entrance, electrical desalter bottom side offers recombination sub-export, recombination sub-export be located at it is de- before crude oil De- rear crude exports are offered on the right side of entrance, at the top of electrical desalter between two parties；Electrical desalter top side offers inflating port, inflation Mouth is located on the right side of de- rear crude exports；Inflating port is connected through the 6th valve with suction port of compressor, and nitrogen is from compressor through the 6th valve Door is passed into electrical desalter；Electrical desalter part is provided with inflating port can change the pressure in electrical desalter by inflating Power.

The crude oil intake section include mixer, the first pump, the second pump, third pump, the first valve, the second valve, Third valve and the 4th valve；First pump intake and demulsifier inlet connection, the first pump discharge is connected to mixed through the first valve Clutch input terminal；Second pump intake and crude oil feeding mouth connection, the second pump discharge are connected to mixer input terminal through the second valve； Third pumps one end and recombination sub-export connection, and the other end is connected to the input terminal of mixer through the 4th valve；The output of mixer End crude oil entrance before de- by third valve connection；Wherein demulsifier is pumped into mixer through the first valve by the first pump, Crude oil is pumped into mixer through the second valve by the second pump；Recombination lease making heavy constituent positioned at electrical desalter middle and lower part exports quilt Third pumping through the 4th valve is pumped into mixer after going out；Demulsifier, crude oil and a part of heavy constituent of extraction are in a mixer Successively enter electrical desalter through third valve, de- preceding crude oil entrance after being sufficiently mixed；It is polynary into crude oil after electrical desalter etc. Successively it is divided into light component, emulsion layer and heavy constituent from top to bottom after component layering.

The crude exports part includes float and the 4th pump；Buoys float with floater shot is in electrical desalter The bottom input port on light component surface, Floater Structure is deep under the liquid level of light component, and the delivery outlet of float is connected to by hose The crude exports after de-；Crude exports are successively through the 5th valve and the 4th pump connection after de-, so that light component is pumped out through the 4th Electrical desalter enters downstream.

First valve, the second valve, third valve, the 4th valve, the 5th valve are connected to through RS485 bus Host computer；The host computer of monitor portion sends control signal to each valve independent control to each valve by RS485 bus.

In the monitor portion, the first ray emitter, the second ray emitter, third ray emitter issue different The ray of frequency, and radiation frequencies are adjusted according to the difference of multicomponent mixture property in electrical desalter is respectively independent.

In the crude exports part, filter screen is installed between the 5th valve and the 4th pump.

The beneficial effects of the present invention are:

The present invention is based on the light components in ray attenuation principle real-time dynamic monitoring judgement oil refining Atmospheric vacuum electrical desalter, cream Change the thickness of layer and heavy constituent, and host computer is transmitted a signal to by RS485 bus, host computer processing obtains light component, cream Change the thickness of layer, heavy constituent, and precisely adjust the draw speed of demulsifier and light component by adjusting corresponding valve opening, protects Light component layer, the emulsion layer, the accurate Dynamic Separation of recombination layering realization in electrical desalter are demonstrate,proved, separating effect had both been improved and electricity is de- Salt efficiency, and the dosage of demulsifier can be saved to greatest extent, it realizes automation Precision management, avoids shadow caused by thinking factor It rings, stable for subsequent atmospheric and vacuum distillation unit covers with excellent stable operation and provide safety guarantee.It present invention can be suitably applied to petrochemical industry Practical in the atmospheric and vacuum distillation unit technology of electric de-salting of field, repacking is convenient, is applicable to different crude oils kind, different pressures work Technology of electric de-salting under condition.

Detailed description of the invention

Fig. 1 is the multicomponent mixture separation system structural schematic diagram suitable for refining oil atmospheric and vacuum distillation unit.

In Fig. 1: 1, monitor portion；2, crude oil intake section；3, electrical desalter part；4, crude exports part；5, pressure Sensor；601, the first ray emitter；602, the second ray emitter；603, third ray emitter；7, crude oil enters before taking off Mouthful；8, light component；9, heavy constituent；10, emulsion layer；11, float；12, filter screen；13, electrical desalter；14, crude exports after taking off； 15, RS485 bus；16, host computer；17, mixer；1801, the first pump；1802, the second pump；1803, third pumps；1804, Four pumps；1805, compressor；1901, the first valve；1902, the second valve；1903, third valve；1904, the 4th valve； 1905, the 5th valve；20, sub-export is recombinated；21, inflating port；22, hose；2301, the first ray detector；2302, it second penetrates Line detector；2303, third ray detector.

Specific embodiment

Following further describes the present invention with reference to the drawings.

Weight component separation system working principle of the invention, the course of work are as follows:

As shown in Figure 1, for the present invention --- suitable for refining oil the multicomponent mixture separation system structural representation of atmospheric and vacuum distillation unit Figure.Including electrical desalter 13 and monitor portion 1, crude oil intake section 2, electrical desalter part 3 and crude exports part 4；Its Middle monitor portion 1 includes pressure sensor 5, the first ray emitter 601, the second ray emitter 602, third ray emitter 603, the first ray detector 2301, the second ray detector 2302, third ray detector 2303,485 bus 15 of RS, on Position machine 16；First ray emitter 601, the second ray emitter 602, third ray emitter 603 are equidistantly horizontally arranged at 13 top inner wall leftward position of electrical desalter, the first ray detector 2301, the second ray detector 2302, third X-ray detection X Device 2303 is equidistantly horizontally arranged at 13 bottom outer wall leftward position of electrical desalter, the first ray detector 2301, the second ray Detector 2302, third ray detector 2303 are penetrated with the first ray emitter 601, the second ray emitter 602, third respectively The correspondence of line transmitter 603 is arranged in opposite directions on same vertical direction；It is right that pressure sensor 5 is mounted on third ray emitter 603 13 top inner wall of electrical desalter of side；601,602,603, three ray detectors of pressure sensor 5 and three ray emitters 2301, it 2302,2303 is communicated to connect by RS485 bus 15 and host computer 16；Electrical desalter part 3 includes de- preceding crude oil entrance 7, sub-export 20 and inflating port 21 are recombinated；13 bottom of electrical desalter offers de- preceding crude oil entrance 7,13 bottom of electrical desalter between two parties Side offers recombination sub-export 20, and recombination sub-export 20 is located at de- preceding 7 right side of crude oil entrance, and 13 top of electrical desalter is opened between two parties Equipped with de- rear crude exports 14；13 top side of electrical desalter offers inflating port 21, and inflating port 21 is located at de- rear crude exports 14 right sides；Inflating port 21 is connected through the 6th valve 1906 with 1805 entrance of compressor, and nitrogen is from compressor 1805 through the 6th valve 1906 are passed into electrical desalter 13.

Crude oil intake section 2 includes 1801, second pump 1802 of the pump of mixer 17, first, third the 1803, first valve of pump 1901, the second valve 1902, third valve 1903 and the 4th valve 1904；First 1801 entrances of pump and demulsifier inlet join Logical, 1801 outlet of the first pump is connected to 17 input terminal of mixer through the first valve 1901；Second 1802 entrances of pump and crude oil feeding Mouth connection, 1802 outlet of the second pump are connected to 17 input terminal of mixer through the second valve 1902；Third pumps 1803 one end and recombination 20 connection of sub-export, the other end are connected to the input terminal of mixer 17 through the 4th valve 1904；The output end of mixer 17 passes through 1903 connection of third valve crude oil entrance 7 before de-；Wherein demulsifier is pumped by the first pump 1801 through the first valve 1901 Mixer 17, crude oil are pumped into mixer 17 through the second valve 1902 by the second pump 1802；Positioned at 13 middle and lower part of electrical desalter Recombination lease making heavy constituent outlet 20 through the 4th valve 1904 be pumped into mixer 17 after 1803 extraction of third pump；Demulsifier, Crude oil and a part of heavy constituent 9 of extraction successively enter through third valve 1903, de- preceding crude oil after being sufficiently mixed in mixer 17 Mouth 7 enters electrical desalter 13；Successively it is divided into light component 8, cream from top to bottom after into the multicomponent mixture layering after electrical desalter 13 Change layer 10 and heavy constituent 9；

Crude exports part 4 includes float 11 and the 4th pump 1804；Float 11 with floater shot floats on electrical desalter 8 surface of light component in 13, the bottom input port of 11 structure of float are deep under the liquid level of light component 8, the delivery outlet of float 11 De- rear crude exports 14 are connected to by hose 22；Crude exports 14 are successively through the 5th valve 1905, filter screen 12 and the after de- Four 1804 connection of pump enter flash column so that light component 8 pumps out electrical desalter 13 into downstream through the 4th pump 1804.

First valve 1901, the second valve 1902, third valve 1903, the 4th valve 1904, the 5th valve 1905 pass through RS485 bus 15 is connected to host computer 16；The host computer 16 of monitor portion 1 is sent to each valve by RS485 bus 15 and is controlled Signal processed is to each 1901,1902,1903,1904,1905 independent control of valve.

In monitor portion 1, the first ray emitter 601, the second ray emitter 602, third ray emitter 603 are issued The ray of different frequency, and radiation frequencies are adjusted according to the difference of multicomponent mixture property in electrical desalter 13 is respectively independent.Wherein Safety valve, purposes are set near inflating port 21 at 13 top of electrical desalter are as follows: set once the pressure of electrical desalter 13 is higher than Determine threshold value, is emptied for urgent discharging；Discharge valve is set close to heavy constituent outlet port in 13 bottom of electrical desalter, it is de- for electricity Heavy constituent thickness is exceeded in salt cellar 13 and when not can be effectively controlled liquid level, is used for dump.

For being suitable for atmospheric and vacuum distillation unit, the accurate separation process step of dynamic multicomponent mixture is as follows in real time:

Step 1) is by electrical desalter 13 and monitor portion 1, crude oil intake section 2, electrical desalter part 3 and crude exports Part 4 is successively installed and is connected, and the second valve 1902 is kept to open always；Crude oil and emulsifier are sufficiently mixed through mixer 17 Afterwards, electrical desalter 13 is entered by de- preceding crude oil entrance 7, is divided into light component 8, emulsion layer 10 from top to bottom in electrical desalter 13 With heavy constituent 9；

Step 2) the first ray emitter 601, the second ray emitter 602, third ray emitter 603 emit frequency respectively The different ray of rate, successively sequentially pass through light component 8, emulsion layer 10, heavy constituent 9 arrive separately at the first ray detector 2301, Second ray detector 2302, third ray detector 2303, three ray detectors are total by RS485 by the signal received Line 15 sends host computer 16 to；Similarly, the signal that pressure sensor 5 receives sends host computer 16 to by RS485 bus 15；

Step 3) host computer 16 receives signal, carries out obtaining multicomponent mixture in electrical desalter after processing calculating to signal each The thickness of layer, and acquisition obtain the information of pressure inside the tank, T₂Indicate 8 thickness of light component, T₃Indicate 10 thickness of emulsion layer, T₄Table Show that 9 thickness of heavy constituent, P indicate the pressure in electrical desalter 13.

Wherein in electrical desalter each thickness degree of multicomponent mixture calculation method are as follows:

1. the ray of the first ray emitter 601 transmitting certain frequency is simultaneously received, emissive porwer by ray detector 2301 For I₀Narrow beam list energy ray, the intensity received be I transmitted intensity, indicate are as follows:

I=I₀×e^-μT (1)

In formula, μ indicates that line attenuation coefficient, T indicate ray penetration thickness；

Assuming that the intensity that ray reaches 8 upper surface of light component is I₁, pass through light component 8 and reach light component 8 and emulsion layer 10 The intensity of interface is I₂, the intensity for reaching the interface of emulsion layer 10 and heavy constituent 9 across emulsion layer 10 is I₃, pass through recombination Dividing 9 intensity for reaching 13 bottom insides of electrical desalter is I₄, received after electrical desalter 13 by the first ray detector 2301 The intensity arrived is I₅；μ₁、μ₂、μ₃、μ₄、μ₅Respectively correspond gas, light component, emulsion layer, heavy constituent and electrical desalter 13 wall thickness Line attenuation coefficient.Approximation noenergy decays when ray passes through gas, i.e. μ₁=0, I₁=I₀；

②μ₂、μ₃、μ₄、μ₅It is demarcated in advance according to experimental method, first measurement μ₅, 13 bottom wall thickness of electrical desalter is Know, i.e. T₅, electrical desalter 13 is interior without medium, and the first ray emitter 601 issues ray, intensity I₀, directly pass through air and electricity 13 wall thickness of desalter, it is I that the first ray detector 2301, which receives transmitted intensity,₅, line attenuation coefficient μ₅It calculates are as follows:

μ₅=-ln (I₅/I₀)/T₅ (2)

For μ₂、μ₃、μ₄Measurement, with μ₂For, electrical desalter 13 has with a thickness of T_nThe light component 8 of (n=1,2,3 ...), First ray emitter 601 issues ray, intensity I₀, the intensity of the intensity after air and light component 8 is I₂, it is then passed through 13 bottom of electrical desalter, the transmitted intensity that the first ray detector 2301 receives are I₅, by T_nChange k times, i.e. k=1,2, 3 ..., n, the intensity after air and light component 8 are I_2k, the first ray detector 2301 receives corresponding k ray signal I_5k, intensity is respectively I₅₁, I₅₂, I_53…, I_5k, then:

It is calculated according to the two above derivation of equation:

By repeatedly measuring, to μ₂₁, μ₂₂, μ₂₃..., μ_2kIt averages, obtains:

It is similar to solve μ₂Method can find out μ₃、μ₄；

3. solution obtains μ₂、μ₃、μ₄、μ₅It afterwards, can in electrical desalter 13 there are when light component 8, emulsion layer 10, heavy constituent 9 List equation group:

Simultaneous can be in the hope of:

Formula (11) is derived from:

μ₂T₂+μ₃T₃+μ₄T₄=-μ₅T₅-ln I₅/I₀ (12)

Similar, in conjunction with the second ray emitter 602 and the second ray detector 2302,603 and of third ray emitter Third ray detector 2303 tests the data obtained and lists three Closure equation groups, is respectively as follows:

In above three formula,M=1,2,3, indicate m group ray The data that transmitter-radiation transducers measures.Host computer finds out unknown quantity T according to equation group simultaneous₂, T₃, T₄。