Design (thesis) Title: Design of packed tower with an annual output of 1.0000 tons of toluene-water mixture.

Correspondence station: major: chemical technology class: xx

Student: xx instructor:

1. Main tasks and objectives of design (paper)

Tower design calculation:

Process calculation of tower A (material and energy balance)

Design and calculation of main process dimensions of B tower and tray

⑶ Hydrodynamic check calculation of benzene distillation column

(4) Selection and calculation of relevant auxiliary equipment

5] Design results, analysis and discussion

2. Basic requirements and contents of design (thesis)

(1) The content of the paper conforms to the writing standard of graduation design.

⑵ The data are reliable, true and representative.

(3) The calculation process is detailed and meets the specification requirements.

⑷ The requirements of paper drawings include: production process control diagram, partial assembly diagram of tower, X-Y diagram and tray load performance diagram.

3. Main references

(1) Lu Meijuan. Principles of chemical engineering. Chemical industry press. 200 1 year 1 edition.

[2] Feng Bohua. Handbook of Chemical Engineering, Volumes 1, 2, 3 and 6. Chemical Industry Press, 1989, 1.

⑶ foreskin is diligent. Design guidance of principles course in South China University of Technology. Beijing university of chemical technology Chemical Engineering Principles Teaching and Research Section.1April, 997.

(4) Chen Hongkai. Chemical separation process. Chemical industry press. 1,1May, 995.

5] Chen Zhongxiu. Chemical thermodynamics. Chemical industry press. 1993 1 1.

Keywords: reflux ratio, distillation, bubble point feeding, equipment, trial and error method

catalogue

Preface ........................................ (7)

Chapter 1 Explanation of Rectification Scheme ....................... (7)

Section 1. 1 Operating pressure ............................ (7)

Section 1.2 feed status ............................ (8)

1.3 section adopts forced reflux (cold reflux) ............... (8).

1.4 heating mode and heating medium .............. (8)

Section 1.5 Tower top condensation mode and cooling medium .............. (8)

Section 1.6 process description ............................ (8)

Section 1.7 Characteristics of Sieve Plate Tower ........................ (9)

Section 1.8 Production Properties and Uses ...................... (9)

Section 1.9 safety and environmental protection in .......................... (1 1)

Chapter II Analysis of Olefin Hydrogenation Saturation Unit ................. (12)

2. Analysis of reaction mechanism and influencing factors of1node

Section 2.2 Material Balance

2.3 Balance of Energy Saving

Chapter 3 Design and Calculation of ....................... for Distillation Column (12)

3. 1 ....................... of tower process calculation (12)

Section 3.2 Design and Calculation of Main Process Dimensions of Trays ..... (25)

Chapter IV Hydrodynamic Calculation of Tower ..................... (3 1)

Section 4. 1 Check ................................ (3 1)

Section 4.2 Calculation of ......................'s Load Performance Diagram (34)

The fifth chapter auxiliary equipment selection calculation ..................... (39)

5. Calculation and selection of1section heat exchanger .................... (39)

Section 5.2 Determination of Pipeline Size ..................... (44)

Section 5.3 Determination of Raw Material Tank and Finished Product Tank ................ (45)

Chapter 6 Design Results Summary and ............... (45)

Section 6. 1 data requirements ............................ (45)

Section 6.2 Design Features ............................ (46)

Problems in Section 6.3 ......................... (46)

Refer to .................................... (47)

Symbol Description ..................................... (48)

Appendix1....................................... (52)

Appendix 2 ....................................... (52)

Appendix 3 ....................................... (52)

Appendix 4 ....................................... (52)

order

This paper aims at the purification and rectification scheme of benzene in the binary system of benzene-toluene solution in industrial production. According to the nature and composition of raw materials and products, a distillation column is designed and the material balance is calculated. Through design accounting and trial calculation, the operating conditions and material composition of the feed, top and bottom of the distillation column are preliminarily determined. At the same time, the basic structure of the distillation column includes the main dimensions of the column, the dimensions of the top condenser, the bottom reboiler, related pipelines and storage tanks. Is calculated and selected. In the process of calculation and design, reference has been made to the Principles of Chemical Engineering, Handbook of Chemical Engineering, Handbook of Process Calculation of Cold Exchange Equipment, Basic Knowledge of Refinery Equipment, Process Principle of Petroleum Processing Unit and other related materials, which provides technical support and guarantee for the design and calculation of distillation column.

Through the design of distillation column and the calculation of material balance, the understanding of chemical principle and process principle of petroleum processing device has been further deepened, the horizon has been broadened, and the knowledge and ability of calculation, drawing and computer use have been improved, which has laid a good foundation for further work.

Chapter 1 Description of rectification scheme

This rectification scheme is suitable for the purification of benzene in the binary system of benzene-toluene solution in industrial production. The purity of benzene tower products in rectification tower is very high, reaching above 99.9%, which requires that the products at the top and bottom of the tower are qualified at the same time, and the temperature changes at the top of the two towers are very narrow (0.02℃), which is far beyond the reach of ordinary rectification temperature control. Therefore, in the actual production process control, only the sensitive board control can meet the requirements. Therefore, the benzene tower adopts temperature difference control.

Section 1. 1 Operating pressure

Distillation operation is carried out at atmospheric pressure, because the boiling point of benzene is low, so it is suitable to operate at atmospheric pressure without decompression or pressurization. At the same time, benzene series compounds are not prone to decomposition, polymerization and other metamorphic reactions at high temperature, and they are liquids (not mixed gases). Therefore, it is not necessary to use reduced pressure or vacuum distillation. On the other hand, pressurized or vacuum distillation consumes a lot of energy, and systems that can operate at normal pressure generally do not need pressurized or vacuum distillation.

Section 1.2 Feeding Status

The feeding state directly affects the relative position and balance relationship between the feeding line (Q line) and the operating line, and also has a great influence on the heat balance of the whole tower. Compared with bubble point feed, if cold feed is used, under certain separation requirements, the number of theoretical plates is less, and a preheater is not needed, but the heat load at the bottom of the tower (generally requiring direct steam heating) is basically balanced in terms of total heat, but the feed temperature fluctuates greatly and the operation is difficult to control; If dew point feed is used, more theoretical trays are needed under certain separation requirements, and the preheater load before feeding is large and energy consumption is large. At the same time, the rising steam quantity in distillation section and stripping section changes greatly, which is difficult to control and greatly influenced by external conditions.

Bubble point feed is between the two, the biggest advantage is that it is less disturbed by the outside world, and the rising steam quantity in the rectification section and stripping section of the tower changes little, which is convenient for design, manufacture and operation control.

1.3 section adopts forced reflux (cold reflux).

The purpose of cold reflux is to control the reflux ratio, and the reflux mode directly affects the reflux temperature.

Section 1.4 heating mode and heating medium of tower bottom

The column kettle adopts tube heat exchanger as indirect heating mode of reboiler, and the heating medium is steam.

Section 1.5 Tower top condensation mode and cooling medium

The top of the tower adopts a tubular condensation cooler, and the cooling medium adopts cooling water.

Section 1.6 Process Description

Since there is no post-hydrogenation unit in the upstream unit, olefins produced in the reforming reaction will be brought into the raw materials of this unit. The existence of olefins will lead to unqualified acid washing colorimetry of benzene and toluene products, so olefin saturation must be carried out.

The process flow of the device includes two parts: olefin hydrogenation reaction unit and rectification unit.

Olefin hydrogenation reaction unit: after being pressurized by the feed pump, the raw materials enter the heat exchanger E 10 1 to exchange heat with the oil generated by the reaction, then enter the heating furnace L 10 1 to be heated, then enter the reactor R 10 1, and enter the heat exchanger E/kloc after the olefin saturation hydrogenation reaction.

The rectification scheme adopts energy-saving forced reflux for process design, and is equipped with an automatic control system with constant feed rate, feed composition and certain separation requirements to ensure normal operation.

Rectification process: 30OC feed liquid enters the feed heat exchanger E 102 from the feed tank, and is preheated to the bubble point (97.65OC with steam as the heating medium) by the feed preheater, and the temperature rises to about 97.65oC, and then enters the rectification tower T 10 1 from the feed inlet for rectification. The partially condensed gas-liquid mixture with the tower top gas temperature of 8 1.52℃ enters the tower top cooler (cooling medium is cooling water), and the condensed material enters the reflux tank V 102, and then part of the feed liquid is pumped into the tower top as reflux by the reflux pump, and the other part enters the product storage tank V 103 as the tower top product through the product cooler, and then passes through the product pump P/kloc. Part of the liquid in the tower kettle enters the reboiler E 103, and flows back to the tower kettle after being heated by steam; the other part exchanges heat with the raw material heat exchanger and then is discharged into the toluene storage tank. During the whole process, all pump outlets are equipped with pressure gauges, and all storage tanks are equipped with exhaust valves to ensure that the storage tanks maintain normal pressure.

Section 1.7 Characteristics of Sieve Plate Tower

Sieve plate tower is one of the earliest used plate towers, and its main advantages are:

(1) is simple in structure and easy to process, and its cost is about 60% of that of bubble column and 80% of that of floating valve column.

(2) Under the same conditions, the production capacity is 20%-40% higher than that of the bubble column;

(3) The tray efficiency is higher, which is about 65438 05% higher than that of the bubble column, but slightly lower than that of the floating valve column;

(4) The gas pressure drop is small, and the pressure drop per plate is about 30% lower than that of the bubble column.

The disadvantage of sieve plate tower is that the sieve plate with small holes is easy to block, and it is not suitable for handling dirty, sticky and solid particles.

Section 1.8 Production Properties and Uses

Properties and uses of 1.8. 1 benzene

Benzene is a kind of flammable, volatile and toxic colorless transparent liquid, and it is a flammable liquid with special aromatic smell. The molecular formula is C6H6, the relative molecular weight is 78. 1 1, the relative density is 0.8794(20℃), the melting point is 5.5 1℃, the boiling point is 80. 1℃, and the flash point is-1. The explosion limit of the mixture of steam and air is 1.4% ~ 8.0%. Insoluble in water, miscible with ethanol, chloroform, ether, carbon disulfide, carbon tetrachloride, glacial acetic acid, acetone and oil. In case of high temperature and open flame, it is easy to burn and explode. It can react violently with oxidants, such as bromine pentafluoride, chlorine, chromium trioxide, perchloric acid, nitroxyl, oxygen, ozone, perchlorate, (aluminum trichloride+perchloric acid fluoride), (sulfuric acid+potassium permanganate), potassium peroxide, (aluminum perchlorate+acetic acid), sodium peroxide, etc., and cannot coexist with diborane. Benzene is one of carcinogens. Benzene is an important raw material for dyes, plastics, synthetic resins, synthetic fibers, drugs and pesticides, and can also be used as power fuel and solvent for paints, rubber and glue. Quality standard: see table 1- 1.

Table 1- 1 Quality Standard of Pure Benzene (GB/T2283-93)

Project index

Super one, two and three categories

At room temperature (18~25℃), the appearance is transparent liquid, which is not deeper than the color of 0.003g potassium dichromate solution per 1000mL water.

Density (20℃)/ kg/m3

Boiling range/℃

At atmospheric pressure (80. 1℃)

Pickling colorimetry

Bromine price/(g/100 ml)

Crystallizing point/℃

Carbon disulfide /(gBr/ 100mL)

Thiophene/(g/100 ml) 876 ~ 880

Neutral experiment

Moisture at room temperature (18~20℃), there is no visible insoluble water.

Properties of 1.8.2 toluene

Toluene has a strong aromatic smell, colorless refractive volatile liquid, and has the smell of benzene. The molecular formula is C7H8, the relative molecular weight is 92. 130, the relative density is 0.866(20℃/4℃), the melting point is -95 ~-94.5℃, the boiling point is 1 10.4℃, and the flash point is 4.44℃ (closed cup) Almost insoluble in water, miscible with ethanol, chloroform, ether, acetone, glacial acetic acid and carbon disulfide. It is easy to catch fire in case of heat, open flame and oxidant. In case of naked flame or reaction with (sulfuric acid+nitric acid), nitrogen tetroxide, silver perchlorate, bromine trifluoride, uranium hexafluoride and other substances, it may cause explosion. If the flow rate is too fast (over 3m/s), there is a danger of generating and accumulating static electricity. Toluene can be chlorinated, nitrated, sulfonated, oxidized and reduced before intermediates such as dyes, medical spices, explosives and refined sugar. Because of its low crystallizing point, toluene can be used as an additive for aviation fuel and internal combustion engine fuel. Quality standard: see table 1-2.

Table 1-2 Toluene Quality Standard (GB/T2284-93)

Project index

Super level 1 and level 2

At room temperature (18~25℃), the appearance is transparent liquid, which is not deeper than the color of 0.003g potassium dichromate solution per 1000mL water.

Density (20℃)/ (kg/m3)

Boiling range/℃

At atmospheric pressure (1 10.6℃)

Pickling colorimetry

Valence of bromine /(GBR/ 100 ml) 863 ~ 868.

Neutral experiment

Moisture at room temperature (18~20℃), there is no visible insoluble water.

1.9 Safety and environmental protection

1.9. 1 safety measures

Benzene is a flammable, explosive and toxic colorless transparent liquid, and its vapor can be mixed with air to form an explosive mixture. Therefore, we should pay special attention to fire prevention and strengthen safety measures.

(1) No open flames and sparks are allowed. The equipment must be sealed to reduce the volatilization and discharge of benzene vapor into the container. The exhaust pipe of the equipment should be discharged into the atmosphere, and its nozzle should be covered with fine metal mesh to prevent the benzene products in the storage tank or distillation equipment from burning due to the tempering of the exhaust steam. The workshop should be equipped with good ventilation equipment to prevent the accumulation of benzene vapor.

(2) All metal structures shall be grounded at several positions according to regulations. In order to prevent the liquid from falling freely and causing electrostatic charge, all pipes leading into the storage tank should be installed near the bottom of the storage tank, and the motor should be placed in a separate workshop.

(3) foam extinguisher and steam fire extinguishing device shall be equipped, and water shall not be used for fire extinguishing.

(4) Before workers enter the storage tank or equipment for cleaning or repair, they must completely drain the oil, cut off all pipelines, and thoroughly clean the equipment with steam before entering, and pay attention to ventilation. Maintenance personnel are forbidden to do hot work in the production area without a hot work permit.

(5) Personnel who enter the production area or have nothing to do with production are not allowed to touch the equipment and measuring instruments.

(6) Remove the leakage of equipment and pipelines in time to prevent accidents such as poisoning, fire and explosion.

(7) Emergency response to leakage: quickly evacuate the personnel in the leaked contaminated area to a safe area, isolate them, and strictly restrict access. Cut off the fire. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and fire protection clothing. Cut off the source of leakage as much as possible to prevent it from entering confined spaces such as sewers and flood discharge ditches. Small amount of leakage: absorbed by activated carbon or other inert substances. You can also brush the emulsion made of incombustible dispersant, and dilute the emulsion and put it into the wastewater system. A large number of water leaks: build a dike or dig a pit to accommodate; Cover with foam to suppress evaporation. Use explosion-proof pump to transfer it to tank car or special collector, and recycle it or transport it to waste disposal site for treatment.

1.9.2 environmental protection

Conscientiously implement the principles and policies of environmental protection, and adhere to the simultaneous design, simultaneous construction and simultaneous commissioning of pollution prevention facilities and production devices. The treatment measures of "three wastes" are analyzed as follows:

(1) waste water: indirect cooling water from each equipment is recycled for coke quenching in the coking workshop, and the separated water from process products is sent to the biochemical unit for treatment. After preliminary precipitation and oil-water separation, the equipment washing water is sent to biochemical treatment.

(2) Waste gas: condensed gas is recycled and burned before being introduced into the tube bundle. The product storage tank is equipped with water spraying device and nitrogen sealing measures to prevent volatilization from polluting the atmospheric environment.

(3) Waste residue: The waste residue generated in the production process is sent to the recovery section for use as raw materials.

Regularly detect the benzene content in each production post and the average content of pollutants in production water to prevent the occurrence of exceeding the standard.

Chapter II Analysis of Olefin Hydrogenation Saturation Unit

2. 1 Analysis of reaction mechanism and influencing factors

(1) reaction mechanism

Monoolefin CnH2n+H2→CnH2n+2

Diene CnH2n-2+2H2→CnH2n+2

cycloalkene

The hydrogenation saturation reaction of olefins is also a hydrogen-consuming exothermic reaction.

(2) Influencing factors of olefin hydrogenation saturation reaction process.

In addition to the catalyst performance, the influencing factors of olefin hydrogenation saturation reaction mainly include raw material properties, reaction temperature, reaction pressure, hydrogen-oil ratio and space velocity.

(1) the nature of raw materials

When processing raw materials with high olefin content, higher reaction severity (i.e. higher reaction pressure and temperature, lower reaction space velocity) is required. In addition, we must pay attention to the inert gas protection of the raw material oil tank, and it is best to directly enter the device to avoid the intermediate contact with air to generate colloid, which will lead to accelerated deactivation of the catalyst.

② reaction temperature

The reaction temperature usually refers to the average temperature of the catalyst bed. The hydrogenation saturation reaction of olefins is exothermic. Increasing the reaction temperature is not conducive to the chemical equilibrium of hydrogenation reaction, but it can obviously improve the chemical reaction speed and refining depth. Excessive reaction temperature will promote the occurrence of hydrocracking side reactions, reduce the liquid yield of products, accelerate the carbon deposition rate of catalysts and reduce the service life of catalysts; The reaction temperature is too low to ensure the removal of impurities.

At very high temperature, olefin saturation is obviously limited. Therefore, there are more residual olefins in products operated at high temperature than in products operated at low temperature. When there are obvious light components in the raw materials, hydrogen sulfide reacts with olefins to produce alcohol when using the new catalyst, and mercaptan can be avoided when operating at lower temperature.

According to the activity of catalyst and olefin content in feed oil, the pre-hydrogenation reaction temperature is generally 150 ~ 180℃. With the extension of operation time, the reaction temperature gradually increased to compensate for the decrease of catalyst activity.

③ reaction pressure

When a certain product quality is required, the service life of the catalyst and the olefin content in the feed oil are mainly considered in the pressure selection. Generally speaking, the higher the pressure, the longer the catalyst operation cycle; The higher the olefin content of feed oil, the higher the selective operating pressure. Increasing the reaction pressure will promote the hydrogenation reaction speed, increase the refining depth and maintain the catalyst activity. However, too high pressure will promote hydrocracking reaction and reduce the total liquid yield of products, while too high reaction pressure will increase investment and operating expenses.

④ Hydrogen-oil ratio

The so-called hydrogen-to-oil ratio is the ratio of hydrogen flow rate to feed rate when reflecting the standard state. It can be expressed by H2/HC. Increasing the hydrogen-oil ratio is not only beneficial to the hydrogenation reaction, but also can prevent coking and protect the catalyst. However, in the case of a certain feed of raw oil, if the ratio of hydrogen to oil is too large, the contact time between raw oil and catalyst will be reduced, which is not conducive to hydrogenation reaction, leading to the decline of refining depth and product quality, and at the same time, it will increase the system pressure drop and compressor load, and increase operating costs.

⑤ airspeed

Space velocity refers to the amount of raw materials treated by catalyst per unit time (mass or volume), which is abbreviated as h- 1. Space velocity is divided into mass space velocity and volume space velocity. The reciprocal of the commonly used volumetric space velocity (LHSV) is equivalent to the reaction contact time, which is called the false contact time. Therefore, the size of space velocity means the length of contact time between raw materials and catalyst. The space velocity is too large, that is, the more raw materials are treated per unit catalyst, the shorter the contact time, which affects the refining depth; If the space velocity is too small, the hydrocracking reaction will be increased, the liquid yield of the product will be reduced, the operation period will be shortened, and the production capacity of the unit will be reduced.

2.2 Material balance

Table 2- 1 Material data of olefin hydrogenation reaction unit: ton/day

Joining and quitting the party

Raw oil 43.2 rectification feed 42.32

Hydrogen loss is 0.52 1.40.

Total 43.72 total 43.72

2.3 Energy balance (taking heating furnace as an example)

2.3. 1 Data of raw materials entering and leaving the heating furnace

See Table 2-2 for raw material data in and out of the heating furnace.

Table 2-2 Raw material data in and out of the heating furnace

Incoming party (80℃) and outgoing party (160℃)

unit

Enthalpy unit of project composition data

Enthalpy of project composition data

M% kcal/kg dry calories

origin

material

Petroleum benzene 0.7 130 16.38 original

material

Petroleum benzene 0.7 154 19.40

Toluene 0.3 128 6.9 12 Toluene 0.3 158 8.532

Olefin olefin

Hydrogen 540 1. 170 hydrogen 1090 2.362

Total 24.462, total 30.294

Note: the olefin content in raw materials is rarely ignored in the calculation process.

2.3.2 Heat balance of heating furnace

As can be seen from Table 2-2, the heat added value of raw oil after passing through the heating furnace is 5.832 W kcal/t. 。

The heating furnace needs combustion gas to provide it. See Table 2-3 for the composition of gas for heating furnace.

Table 2-3 Calculation Table of Gas Composition and Enthalpy of Heating Furnace

Enthalpy analysis data of component volume calorific value

1 H2 2650 44.91190.115

Oxygen 0 1 1.73 0

3 Nitrogen 0 40.56 0

4 carbon dioxide 0.020

5 carbon monoxide 30 1800

6 methane 85291.61.137.438+069.

Seven ethane15186 0.48.50000.00000000085

8 ethylene 14204 0.42 59.6568

9 propane 21742 0.0510.438+0

10 propylene 20638 0.07 14.4466

Isobutane 26 100 0.03 7.83

12 n-butane 2828 1 0.03 8.4843

13 n-butene 27 160 0.02 5.432

14 isobutylene 271600.012.716

15 fumaric acid 27 160 0.02 5.432

16 maleic acid 271600.012.716

17 is higher than c5348180.0310.4454.

Total: 100 1528. 56636.88866866666

Chapter VII References

Principles of Chemical Engineering (1) Volume I, Chemical Industry Press, Third Edition, May 2006.

2 Feng Bohua. Handbook of Chemical Engineering, Volumes 1, 2, 3 and 6. Chemical Industry Press, 1989, 1.

3 foreskin is diligent. Design guidance of principles course in South China University of Technology. Beijing university of chemical technology Chemical Engineering Principles Teaching and Research Section.1April, 997.

4. Chen Hongxuan. Chemical separation process, Chemical Industry Press, May 1995, 1 version.

5 Chen Zhongxiu. Chemical thermodynamics. Chemical industry press. 1993 1 1 version.

6 Shen Fu et al. Process Principles of Petroleum Processing Units (Volume I). Sinopec press. August 2004 No.65438 +0 Edition.

Liu Wei, et al. Handbook of process calculation for cold exchange equipment. Sinopec press. Version 1, September 2003.

8. edited by Ma Bingqian. Basic knowledge of refining equipment. Sinopec press. Version 1, June 2003.

9. Zhou Zhicheng et al. Automation of petrochemical instruments. Sinopec press. 1994 may 1 version.

10. Tian Jiahui. Chemical equipment. Sinopec press. 1996 June 1 version.

1 1. Shen Chuyang. Process principle of petroleum processing equipment. Sinopec press. Version 1, August 2004.

12. Lu Meijuan. Principles of chemical engineering. Chemical industry press. Version 10, June 2006.

Symbolic description

Heat exchange area m2

Aa foaming area m2

Cross-sectional area m2 of Af downcomer

Effective mass transfer area m2

Ao grid area m2

Cross-sectional area m2 of AT tower

A mass fraction-

Load factor-

CP specific heat kj/kg.oc (kj/kg.k)

Overhead product flow rate Kmol/h (kg/hour)

Nominal diameter m of Dg

DT tower diameter m

D tube inner diameter mm

D 1 pipe outside diameter mm

Do aperture mm

Average diameter of dm tube mm

E shrinkage coefficient of liquid flow-

ET total tray efficiency-

Ev mist entrains kg liquid/kg gas.

Feed flow Kmol/h (kg/hour)

H tower height m

The height of transparent night layer on HL plate is mm

HT plate spacing m

Clear night layer height m in Hd downcomer

HD tower top space height m

Height m of space at the bottom of HB tower

Pressure drop m of hd gas through dry plate

Distance m from lower edge of ho downcomer to tray

What is the height of the head on the overflow weir?

Pressure drop m of high pressure gas passing through the tray

Hr Pressure drop m of liquid passing through downcomer

Height m of hw overflow weir

Pressure drop m caused by surface tension of hσ liquid

Ko total heat transfer coefficient Kcal/m2. H.oC based on inner wall.

K stability coefficient

L liquid flow Kmol/h (kg/hour, m3/hour)

Length of lW overflow weir

Mass flow rate of ms coolant Kg/h

N Actual number of pallets-

NT theoretical plate number-

Number of directors of Nt heat exchanger-

Start numbering

Q heat exchanger heat load w

R reflux ratio-

Minimum reflux ratio-

Scale resistance coefficient m2 in Rsi heat exchange tubes? h？ Supervisor/calories

R latent heat of gasification KJ/Kg

Tc critical temperature k

T-hole spacing mm

Tp plate thickness mm

Ua gas velocity m/s based on bubbling area

Ultrafiltration gas displacement speed m/s

Empty tower gas velocity m/s

Uo gas velocity m/s based on sieve area

Uow leakage point gas velocity m/s

The velocity of the rising gas in the V tower is 1000 mol/h (kg/h, m3/h).

Liquid output at the bottom of W tower Kmol/h(Kg/h)

Width of Wc edge area m(mm)

Width of Wd downcomer m(mm)

Ws tray entrance anding district width m(mm)

Ws' pallet outlet anding district width m(mm)

X liquid phase mole fraction-

Y gas phase mole fraction-

Relative volatility-

Ai Heat transfer film coefficient Kcal/m2 based on inner wall? h？ commander

Coefficient Kcal/m2 of heat transfer film based on Ao external wall? h？ commander

β expansion coefficient-

σ surface tension dyn/cm2

ρL liquid phase density Kg/m3

ρv(g) gas phase density Kg/m3

μ viscosity Cp

Porosity-

Ф load factor-

τ residence time s

λ