CN108153948B - Method for determining length of lignite drying pipe - Google Patents

Method for determining length of lignite drying pipe Download PDF

Info

Publication number
CN108153948B
CN108153948B CN201711340256.7A CN201711340256A CN108153948B CN 108153948 B CN108153948 B CN 108153948B CN 201711340256 A CN201711340256 A CN 201711340256A CN 108153948 B CN108153948 B CN 108153948B
Authority
CN
China
Prior art keywords
drying
lignite
particles
temperature
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201711340256.7A
Other languages
Chinese (zh)
Other versions
CN108153948A (en
Inventor
李玉
赵兴春
崔凯平
王亮
阎欣军
李淑萍
吕太
刘洪宪
刘国伟
卢洪波
郑建祥
姚惯升
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dongdian Technology Development Headquarters Of Northeast Electric Power University
Northwest Electric Power Design Institute of China Power Engineering Consulting Group
Original Assignee
Dongdian Technology Development Headquarters Of Northeast Electric Power University
Northwest Electric Power Design Institute of China Power Engineering Consulting Group
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dongdian Technology Development Headquarters Of Northeast Electric Power University, Northwest Electric Power Design Institute of China Power Engineering Consulting Group filed Critical Dongdian Technology Development Headquarters Of Northeast Electric Power University
Priority to CN201711340256.7A priority Critical patent/CN108153948B/en
Publication of CN108153948A publication Critical patent/CN108153948A/en
Application granted granted Critical
Publication of CN108153948B publication Critical patent/CN108153948B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/14—Pipes

Abstract

The invention discloses a method for determining the length of a lignite drying tube, which comprises the steps of establishing a lignite drying model in a drying tube; obtaining physical property parameters of lignite particles and drying medium parameters; calculating the hot flue gas quantity for drying and the moisture content of the outlet flue gas according to the energy conservation; calculating the speed of the lignite particles at each section of the descending drying pipe; considering the linear relation between the drying equilibrium time and the square of the particle size to obtain the residence time of the lignite particles in the drying pipe; the specific pipe length of the descending drying pipes for different coal types is calculated, the accurate pipe length required by lignite drying can be obtained through a drying pipe length determination formula, the precision is improved, and volatilization analysis caused by incomplete drying or excessive drying of lignite is prevented.

Description

Method for determining length of lignite drying pipe
Technical Field
The invention belongs to the technical field of coal-fired power generation, relates to the field of a pulverizing system and a combustion system of a lignite-fired power station boiler, and particularly relates to a method for determining the length of a lignite drying pipe.
Background
Lignite is a fossil energy with abundant reserves, which accounts for about 40% of the total reserves of coal resources in the world, and has the advantages of shallow burial depth and low mining cost. The lignite resources in China are abundant in reserves and wide in distribution, but the utilization degree of the lignite resources is relatively low due to the high moisture of the lignite. The high moisture content not only severely reduces the calorific value of the lignite and increases the transportation cost, but also brings about a plurality of problems for the application of the lignite. Therefore, before the lignite is used, the lignite needs to be dried and upgraded, 60-70% of moisture in the lignite is removed, the heat value of the lignite per unit mass is improved, and the fuel property of the lignite is improved. However, because the lignite has the characteristic of high volatile content, if the lignite is dried excessively, a large amount of volatile components may be separated out, so that the danger of explosion of a pulverizing system is caused. In order to efficiently and safely utilize lignite resources, the problem of drying and dewatering of lignite is a basic necessary precondition.
In a coal-fired electric power unit, the drying process of coal is mainly completed in a pulverizing system. In China, most of lignite-fired power plants adopt a fan coal mill to grind coal dust, and three-medium drying systems are correspondingly arranged to dry the coal dust, so that the lignite-fired power plants belong to a typical closed system. The design and calculation technology of a coal pulverizing system of a thermal power plant (DL/T5145-2005) in China: when the high-moisture lignite is adopted, a secondary medium or a tertiary medium formed by mixing high (low) temperature smoke and hot air is preferably adopted as the drying agent. The three-medium drying system is a system for drying lignite particles ground by a fan coal mill by using high-temperature furnace smoke, low-temperature furnace smoke and hot air as drying media. This system has certain requirements for the temperature range of the respective drying medium: the high-temperature flue gas is generally 1050-1155 ℃, the hot air temperature is generally 250-350 ℃, and the low-temperature flue gas is generally 80-170 ℃. The high-temperature flue gas extracted from the top end of the hearth and the low-temperature flue gas extracted from the tail flue are mixed with hot air in the mixing tank, the lignite is conveyed to the descending drying pipe from a coal conveying belt of the coal feeder, and the drying medium dries the lignite in the descending drying pipe in the same direction. In the drying process, because the moisture content of the lignite is different, the temperature of a drying medium is adjusted accordingly, and the proportion of high-temperature and low-temperature furnace smoke and hot air is different.
The water existing form in the brown coal can be divided into three types: exterior water, capillary water and bound water. The removal of moisture from lignite has an important relationship with factors such as the particle size composition of coal, the type of coal and the composition of coal rock, the drying rate is influenced by the forward and reverse flow movement between the drying medium and the drying material, and the drying rate is influenced by the properties of the drying medium, such as temperature, flow rate and the thickness of a coal sample.
At present, in the related standards and research documents of boilers in China, the design method of the length of a descending drying pipe of a fan mill three-medium drying system is not introduced in detail, so that the design of the length of the descending drying pipe is basically based on experience all the time, and no clear design standard exists. However, the drying process of the lignite particles in the downstream drying tube is seriously related to the safety and reliability of the system: if the design of the descending drying pipe is too long, the lignite is easily dried excessively, not only can the coal be incinerated, but also a large amount of volatile matters can be separated out, and the lignite is easy to explode; if the design of the descending drying pipe is too short, the lignite is not dried sufficiently, the integral heat efficiency of the boiler is affected, and the economical efficiency is reduced.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for determining the length of a lignite drying tube, which can obtain accurate tube length required by lignite drying, improve the precision and prevent volatilization analysis caused by incomplete drying or excessive drying of lignite.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for determining the length of a lignite drying tube body comprises the following steps:
the method comprises the following steps: establishing a drying process model of the lignite particles in a drying pipe;
step two: obtaining physical property parameters of lignite particles and drying medium parameters;
step three: according to the parameters in the second step, calculating the hot flue gas quantity for drying and the moisture content of the flue gas at the outlet of the drying pipe by energy conservation;
step four: determining the speeds of the lignite particles in different stages of the drying pipe by the second step and the third step;
step five: determining an empirical formula between drying equilibrium time and particle size to obtain the residence time of the lignite particles in the drying pipe;
step six: and D, obtaining a formula for calculating the length of the downstream drying tube according to the speeds of the different stages obtained in the step four and the time obtained in the step five, and calculating the length of the drying tube.
Further, the drying process model of the first step comprises a preheating drying section model, a constant-speed evaporation drying section model and a deceleration evaporation drying section model.
Further, in the third step, the hot flue gas volume for drying and the moisture content of the outlet flue gas are calculated through energy conservation, wherein the energy conservation comprises material conservation and heat balance, and the hot flue gas volume for drying and the moisture content of the outlet flue gas of the drying pipe are solved through the following formula:
G0(ω1-ω2)＝L(Y2-Y1)；
LI1-G0(cm+4.186ω1)tm1＝LI2-G0(cm+4.186ω2)tm2
wherein G is0The unit of the mass flow of the coal powder is kg/h; i is1，I2Expressing the heat content of the gas entering and exiting the drying pipe, and the unit is kW/(m)3K); l represents the amount of hot flue gas for drying, and the unit is kg/h; c. CmRepresents the specific heat capacity, expressed in kJ/(kg. DEG C.); omega1，ω2Represents the moisture content of the coal powder entering and exiting the dryer in%; t is tm1，tm2The temperature of the pulverized coal entering and exiting the dryer is expressed in units of ℃; y is1，Y2Representing the moisture content of the air entering and exiting the dryer in kg/kg.
Further, the empirical formula between the drying equilibrium time and the particle size in the fifth step is as follows:
Figure BDA0001508236520000041
where T is temperature, τ is time, T1Is an initial temperature, T0For the equilibrium temperature, a is an experimentally determined constant, the value of a is essentially constant at different particle sizes, 3.3, and d is the particle size.
Further, the speed of each section of the drying tube in the fourth step is as follows:
velocity of particles in the preheating section: calculating the temperature t of the material from the heat balance equationm1Increasing to the wet bulb temperature twRequired heat Q of flue gas1；
Q1＝G0(cm+4.186ω1)(tw-tm1)；
Wherein: t is twExpressing the wet bulb temperature of the coal dust particles, with the unit of DEG C, from Q1The temperature t of the gas at the end of the preheating zone is obtained, and the average temperature t of the gas in the section is obtainedaveAnd then the Reynolds number Re is calculated,
Figure BDA0001508236520000042
Figure BDA0001508236520000043
Q1＝L×cp×(t1-t)；
wherein, t1，t2Represents the temperature of the air in and out of the drying gas in units of ℃; re represents a Reynolds number; rho represents the density in kg/m3(ii) a dp represents the diameter of the coal dust particles in m; v. ofmRepresenting the initial velocity of the material, taking vm＝0。
Substituting into the gas-solid phase heat transfer correlation obtained by integration so as to reversely deduce the required heat supply quantity Q1There are values of Reynolds numbers Re to Re';
Figure BDA0001508236520000044
Figure BDA0001508236520000045
wherein: a. therRepresents an Archimedes standard number; a represents the heat transfer surface area in m of the particles in the dryer volume2/m3(ii) a λ represents the thermal conductivity in kW/(m · K); μ represents dynamic viscosity, pas;
by
Figure BDA0001508236520000046
To obtain the corresponding particle velocity vg；
Speed of particles in constant rate evaporation section (surface evaporation): determining the heat quantity Q 'required from w to w in the material moisture content of the speed-reducing evaporation section according to the experience of actual operation'2Performing sectional calculation by using airflow drying, and taking the outlet condition of each section as the inlet condition of the next section;
L1·cp·(t-t′)＝G0(w1-w)[qm+1.88(t′-tm)]
wherein q ismIs at tmThe vaporization potential of (a) t' is at the moisture content wThe temperature of the air, in units of;
from Q'2The corresponding gas temperature t when the moisture content of the material is w is obtained, and the average temperature t in the section is further obtainedaveAnd average humidity YaveDetermining the physical property data of the gas and obtaining the Reynolds number Re of the initial point of the section;
Figure BDA0001508236520000051
Figure BDA0001508236520000052
wherein (Delta t)mIs the average temperature difference of heat transfer, and the unit is;
v in the formulamNamely the constant-speed evaporation section speed of the lignite particles;
velocity of particles in the deceleration evaporation stage: determining the heat quantity Q required by the moisture content of the material in the speed-reducing evaporation section from w to w' according to the experience of actual operation3', from Q3' calculating the average temperature t of the gas in the sectionaveAnd average humidity YaveDetermining the physical constant of the gas to obtain the Reynolds number R of the sedimentation in the sectionetAnd velocity vt；
L1·cp·(t-t′)＝G0(w-w′)[r+1.88(t′-tm)]
Figure BDA0001508236520000053
Figure BDA0001508236520000054
Wherein v istIs the settling velocity of the coal dust particles.
Further, the length of the descending drying tube in the sixth step is determined by the drying time and the particle settling speed of each section obtained in the fifth step
The method for determining the length of the lignite drying tube body comprises the steps of establishing a lignite drying model in the drying tube; obtaining physical property parameters of lignite particles and drying medium parameters; calculating the hot flue gas quantity for drying and the moisture content of the outlet flue gas according to the energy conservation; calculating the speed of the lignite particles at each section of the descending drying pipe; considering the linear relation between the drying equilibrium time and the square of the particle size to obtain the residence time of the lignite particles in the drying pipe; the specific pipe length of the descending drying pipes for different coal types is calculated, the accurate pipe length required by lignite drying can be obtained through a drying pipe length determination formula, the precision is improved, and volatilization analysis caused by incomplete drying or excessive drying of lignite is prevented.
Drawings
FIG. 1 flow chart of the present invention
FIG. 2 sectional graph of lignite drying process according to the present invention
Detailed Description
The invention is further explained below with reference to specific embodiments and the drawing of the description.
As shown in fig. 1, the method for determining the length of the lignite drying tube body of the invention comprises the following steps:
the method comprises the following steps: establishing a drying process model of the lignite particles in a drying pipe;
the lignite particle drying process model is as follows: (1) the preheating drying section (2) is a constant-speed evaporation drying section (3) and the speed reduction evaporation drying section is arranged;
step two: obtaining physical property parameters of lignite particles and drying medium parameters;
step three: according to the parameters in the second step, calculating the hot flue gas quantity for drying and the moisture content of the outlet flue gas through energy conservation;
conservation of energy includes conservation of materials and heat balance:
G0(ω1-ω2)＝L(Y2-Y1)；
LI1-G0(cm+4.186ω1)tm1＝LI2-G0(cm+4.186ω2)tm2
wherein G is0Representing mass flow of coal finesAmount in kg/h; i is1，I2Expressing the heat content of the gas entering and exiting the drying pipe, and the unit is kW/(m)3K); l represents the amount of hot flue gas for drying, and the unit is kg/h; c. CmRepresents the specific heat capacity, expressed in kJ/(kg. DEG C.); omega1，ω2Represents the moisture content of the coal powder entering and exiting the dryer in%; t is tm1，tm2The temperature of the pulverized coal entering and exiting the dryer is expressed in units of ℃; y is1，Y2Representing the moisture content of the air entering and exiting the dryer in kg/kg.
Step four: determining the speeds of the lignite particles in different stages of the drying pipe by the second step and the third step;
velocity of particles in the preheating section: calculating the temperature t of the material from the heat balance equationm1Increasing to the wet bulb temperature twRequired heat Q of flue gas1；
Q1＝G0(cm+4.186ω1)(tw-tm1)；
Wherein: t is twExpressing the wet bulb temperature of the coal dust particles, with the unit of DEG C, from Q1The temperature t of the gas at the end of the preheating zone is obtained, and the average temperature t of the gas in the section is obtainedaveAnd then the Reynolds number Re is calculated,
Figure BDA0001508236520000071
Q1＝L×cp×(t1-t)；
wherein, t1，t2Represents the temperature of the air in and out of the drying gas in units of ℃; re represents a Reynolds number; rho represents the density in kg/m3(ii) a dp represents the diameter of the coal dust particles in m; v. ofmThe initial velocity of the material is represented by vm ═ 0.
Substituting into the gas-solid phase heat transfer correlation obtained by integration so as to reversely deduce the required heat supply quantity Q1There are values of Reynolds numbers Re to Re'.
Figure BDA0001508236520000072
Figure BDA0001508236520000073
Wherein: a. therRepresents an Archimedes standard number; a represents the heat transfer surface area in m of the particles in the dryer volume2/m3(ii) a λ represents the thermal conductivity in kW/(m · K); μ represents dynamic viscosity, pas;
by
Figure BDA0001508236520000074
To obtain the corresponding particle velocity vg。
Speed of particles in constant rate evaporation section (surface evaporation): determining the heat quantity Q 'required from w to w in the material moisture content of the speed-reducing evaporation section according to the experience of actual operation'2And calculating by using the airflow drying section, and taking the outlet condition of each section as the inlet condition of the next section.
L1·cp·(t-t′)＝G0(w1-w)[qm+1.88(t′-tm)]
Wherein q ismIs at tmThe vaporization potential, t' is the temperature of the air at the moisture content w, in degrees c.
From Q'2The corresponding gas temperature t when the moisture content of the material is w is obtained, and the average temperature t in the section is further obtainedaveAnd average humidity YaveFrom this, the gas property data can be determined, and the Reynolds number Re at the starting point of the stage can be obtained.
Figure BDA0001508236520000081
Figure BDA0001508236520000082
Wherein (Delta t)mThe heat transfer average temperature difference is given in degrees centigrade.
V in the formulamNamely the lignite particles are evaporated at a constant speedSegment velocity.
Velocity of particles in the deceleration evaporation stage: determining the heat quantity Q required by the moisture content of the material in the speed-reducing evaporation section from w to w' according to the experience of actual operation3', from Q3' calculating the average temperature t of the gas in the sectionaveAnd average humidity YaveDetermining the physical constant of the gas to obtain the Reynolds number R of the sedimentation in the sectionetAnd velocity vt。
L1·cp·(t-t′)＝G0(w-w′)[r+1.88(t′-tm)]
Figure BDA0001508236520000083
Figure BDA0001508236520000084
Wherein v istI.e. the settling velocity of the coal dust particles.
Step five: determining an empirical formula between drying equilibrium time and particle size to obtain the residence time of the lignite particles in the drying pipe;
considering the linear relationship between the drying equilibration time and the square of the particle size, specifically:
Figure BDA0001508236520000091
wherein T is temperature, T1Is an initial temperature, T0For the equilibrium temperature, A is the parameter and d is the particle size.
Step six: and D, obtaining a formula for calculating the length of the downstream drying tube according to the speeds of the different stages obtained in the step four and the time obtained in the step five, and calculating the length of the tube.
The formula of the length of the descending drying tube specifically comprises the following steps:
Figure BDA0001508236520000092
wherein, L tableShowing the length of a descending drying tube m; eta represents the dehydration rate of coal particles in units; moutRepresents the amount of extra-basal water received in%; mtRepresents the total water content of the received base, and the unit is%; r1Represents the proportion of particles having an equivalent diameter of greater than 1mm in%; r3Indicating the proportion of particles having an equivalent diameter of greater than 3mm in%.
In the drying process, because the material always has a certain geometric size, even if the pulverized coal is fine, the pulverized coal can be regarded as particles with a certain size from a microscopic view, in practice, the heat and mass transfer process is different in mechanisms between hot air flow and material particles and in the material particles, and the heat and mass transfer process is theoretically divided into the heat and mass transfer process of the hot air flow and the material surface and the heat and mass transfer process in the material. The difference between the two processes affects the whole drying process of the material, and the two processes play different leading and restricting roles in different drying stages, so that the former stage always performs at a faster and stable speed while the latter stage performs at a slower and slower speed when the wet material is dried generally. As shown in figure 2, the whole dehydration process is divided into a preheating section, a constant-speed evaporation section and a speed-reducing evaporation section according to the dehydration rule of the materials, and the dividing points of the water content of the materials among the sections are Xin, Xa and Xb respectively. Fig. 2 shows the relationship between the moisture content and the temperature of the material as the length of the drying tube increases during the whole drying and dewatering process of the lignite granules.
The foregoing is a preferred embodiment of the present invention, and various modifications and substitutions can be made by those skilled in the art without departing from the technical principle of the present invention, and should be considered as the protection scope of the present invention.

Claims (4)

1. A method for determining the length of a lignite drying tube body is characterized by comprising the following steps:
the method comprises the following steps: establishing a drying process model of the lignite particles in a drying pipe;
step two: obtaining physical property parameters of lignite particles and drying medium parameters;
step three: according to the parameters in the second step, calculating the hot flue gas quantity for drying and the moisture content of the flue gas at the outlet of the drying pipe by energy conservation;
step four: determining the speeds of the lignite particles in different stages of the drying pipe by the second step and the third step;
step five: determining an empirical formula between drying equilibrium time and particle size to obtain the residence time of the lignite particles in the drying pipe;
step six: according to the speeds of different stages obtained in the fourth step and the time obtained in the fifth step, obtaining a formula for calculating the length of the downstream drying pipe, and calculating the length of the drying pipe;
step one, a drying process model comprises a preheating drying section model, a constant-speed evaporation drying section model and a deceleration evaporation drying section model;
in the fourth step, the speed of each section of the drying tube is as follows:
velocity of particles in the preheating section: calculating the temperature t of the material from the heat balance equationm1Increasing to the wet bulb temperature twRequired heat Q of flue gas1；
Q1＝G0(cm+4.186ω1)(tw-tm1)；
Wherein: t is twRepresenting the wet bulb temperature of the coal dust particles; t is tm1Is the temperature of the material; g0Is the mass flow of the coal powder; c. CmIs the specific heat capacity of coal particles; omega1Is the moisture content of coal dust, from Q1The temperature t of the gas at the end of the preheating zone is obtained, and the average temperature t of the gas in the section is obtainedaveAnd then the Reynolds number Re is calculated,
Figure FDA0003017011500000011
wherein Re represents Reynolds number; dp represents a pulverized coal particle diameter; vgRepresents the initial velocity of the drying gas; vmRepresenting the initial velocity of the material, taking vm0; ρ represents a density; mu.sgRepresents the kinetic viscosity; t is t1，t2Indicating inlet and outlet dry gas(ii) temperature; l represents the amount of dry gas; c. CpWhich represents the specific heat capacity of the dry gas,
substituting into the gas-solid phase heat transfer correlation obtained by integration so as to reversely deduce the required heat supply quantity Q1There are values of Reynolds numbers Re to Re';
Figure FDA0003017011500000021
Figure FDA0003017011500000022
wherein: a. therRepresents an Archimedes standard number; a represents the heat transfer surface area of the particles per unit volume in m2/m3；λgRepresents the gas thermal conductivity; μ denotes the dynamic viscosity,. DELTA.tmRepresenting the heat exchange temperature difference, and g represents a gravity constant; rhomDenotes the solid particle density, pgRepresents the gas density; d represents the inner diameter of the drying pipe; v. ofyRepresenting the specific volume of the flue gas; v. ofgWhich is indicative of the velocity of the particles,
by
Figure FDA0003017011500000023
To obtain the corresponding particle velocity vg；
Speed of particles in constant rate evaporation section: the heat quantity Q ' required from w to w ' of the material moisture content of the speed-reducing evaporation section is determined according to actual operation experience '2Performing sectional calculation by using airflow drying, and taking the outlet condition of each section as the inlet condition of the next section;
L1·cp·(t-t′)＝G0(w1-w)[qm+1.88(t′-tm)]
wherein L is1Represents the volume of dry flue gas used in the section; c. CpRepresents the specific heat capacity of the dry gas; t, t' represents the inlet and outlet drying gas temperature; g0Is the mass flow of the coal powder; w is a1W represents the average moisture content of the particles at the inlet and outlet; q. q.smIs at tmPotential for vaporization of time tmRepresents the inlet coal particle temperature;
from Q'2The corresponding gas temperature t when the moisture content of the material is w is obtained, and the average temperature t in the section is further obtainedaveAnd average humidity YaveDetermining the physical property data of the gas and obtaining the Reynolds number Re of the initial point of the section;
Figure FDA0003017011500000024
Figure FDA0003017011500000025
wherein (Delta t)mIs the heat transfer average temperature difference; t is t1，t2The temperature of the drying gas for the air to enter and exit; t is t3Is the average temperature of the particles, V in the formulamNamely the constant-speed evaporation section speed of the lignite particles;
velocity of particles in the deceleration evaporation stage: determining the heat quantity Q required by the moisture content of the material in the speed-reducing evaporation section from w to w' according to the experience of actual operation3', from Q3' calculating the average temperature t of the gas in the sectionaveAnd average humidity YaveDetermining the physical constant of the gas to obtain the Reynolds number R of the sedimentation in the sectionetAnd velocity vt；
L1·cp·(t-t′)＝G0(w1-w)[qm+1.88(t′-tm)]
Figure FDA0003017011500000031
Figure FDA0003017011500000032
Wherein v istIs the settling velocity of the coal dust particles.
2. The lignite drying tube body length determining method according to claim 1, wherein: and in the third step, the hot flue gas volume for drying and the moisture content of the outlet flue gas are calculated through energy conservation, wherein the energy conservation comprises material conservation and heat balance, and the hot flue gas volume for drying and the moisture content of the outlet flue gas of the drying pipe are solved through the following formula:
G0(ω1-ω2)＝L(Y2-Y1)；
LI1-G0(cm+4.186ω1)tm1＝LI2-G0(cm+4.186ω2)tm2
wherein G is0Representing the mass flow of the pulverized coal; i is1，I2Representing the enthalpy of the gas entering and exiting the drying tube; l represents the amount of hot flue gas for drying; c. CmRepresents the specific heat capacity; omega1，ω2Represents the moisture content of the coal fines entering and exiting the dryer; t is tm1，tm2Representing the temperature of the pulverized coal entering and exiting the dryer; y is1，Y2Representing the moisture content of the air entering and exiting the dryer.
3. The lignite drying tube body length determining method according to claim 1, wherein: the empirical formula between the drying equilibrium time and the particle size in the fifth step is as follows:
Figure FDA0003017011500000041
where T is temperature, τ is time, T1Is an initial temperature, T0For the equilibrium temperature, a represents the heat transfer surface area per unit volume of the particles, and is an experimentally determined constant, the value of a is 3.3 for different particle sizes, and d is the particle size of the particles.
4. The lignite drying tube body length determining method according to claim 1, wherein: and the length of the descending drying pipe in the sixth step is determined by the drying time and the particle settling speed of each section obtained in the fifth step.
CN201711340256.7A 2017-12-14 2017-12-14 Method for determining length of lignite drying pipe Active CN108153948B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711340256.7A CN108153948B (en) 2017-12-14 2017-12-14 Method for determining length of lignite drying pipe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711340256.7A CN108153948B (en) 2017-12-14 2017-12-14 Method for determining length of lignite drying pipe

Publications (2)

Publication Number Publication Date
CN108153948A CN108153948A (en) 2018-06-12
CN108153948B true CN108153948B (en) 2021-07-13

Family

ID=62466236

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711340256.7A Active CN108153948B (en) 2017-12-14 2017-12-14 Method for determining length of lignite drying pipe

Country Status (1)

Country Link
CN (1) CN108153948B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201237420Y (en) * 2008-07-04 2009-05-13 韩吉生 Hot wind type tube bundle drying machine
EP2154227A1 (en) * 2008-07-24 2010-02-17 RWE Power Aktiengesellschaft Method for manufacturing of fuel pellets of lignite xylite and fuel pellets comprising lignite xylite
CN202087526U (en) * 2011-04-15 2011-12-28 煤炭科学研究总院唐山研究院 Lower-order coal pulse air flow separation and drying integrated device
CN102798133A (en) * 2011-05-27 2012-11-28 中国电力工程顾问集团东北电力设计院 Fan grinding hot blast powder feeding and pulverizing system utilizing flue gas drying and water recycling
CN104764299A (en) * 2014-01-06 2015-07-08 山东科院天力节能工程有限公司 Heat power fluidized evaporation separation device and process with external pressure

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7901473B2 (en) * 2003-12-12 2011-03-08 Coaltek, Inc. Pre-burning, dry process methodology and systems for enhancing solid fuel properties
CN103060039A (en) * 2012-12-27 2013-04-24 中国五环工程有限公司 Drying and shaping process for lignite
CN103445065B (en) * 2013-09-02 2015-03-25 河南黄国粮业股份有限公司 Vortex air flow drying method for glutinous rice

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201237420Y (en) * 2008-07-04 2009-05-13 韩吉生 Hot wind type tube bundle drying machine
EP2154227A1 (en) * 2008-07-24 2010-02-17 RWE Power Aktiengesellschaft Method for manufacturing of fuel pellets of lignite xylite and fuel pellets comprising lignite xylite
CN202087526U (en) * 2011-04-15 2011-12-28 煤炭科学研究总院唐山研究院 Lower-order coal pulse air flow separation and drying integrated device
CN102798133A (en) * 2011-05-27 2012-11-28 中国电力工程顾问集团东北电力设计院 Fan grinding hot blast powder feeding and pulverizing system utilizing flue gas drying and water recycling
CN104764299A (en) * 2014-01-06 2015-07-08 山东科院天力节能工程有限公司 Heat power fluidized evaporation separation device and process with external pressure

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
An experimental study on the drying kinetics of lignite in high temperature nitrogen atmosphere;Hong-Jun Zheng 等;《Fuel Processing Technology》;20141031;第126卷;259-265 *
管式气流干燥器提质低阶煤理论与技术的研究;田忠坤;《中国博士学位论文全文数据库 工程科技Ⅰ辑》;20110315(第03期);B021-21 *
褐煤管式气流干燥流场的数值模拟研究及干燥管结构优化;李小艳;《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》;20130515(第05期);C039-13 *

Also Published As

Publication number Publication date
CN108153948A (en) 2018-06-12

Similar Documents

Publication Publication Date Title
CN102419079A (en) Solid particle material composite grading and drying device and method
Yan et al. A novel lignite pre-drying system integrated with flue gas waste heat recovery at lignite-fired power plants
CN204240348U (en) Superheat steam drying powder process type coal-burning boiler unit and electricity generation system
CN100443840C (en) High volatile coal dust rotary drying process
CN108153948B (en) Method for determining length of lignite drying pipe
CN105241182B (en) Brown coal drying system and its drying means
CN104132359A (en) Open powder making steam warm air type boiler unit and power generation system thereof
CN104132362A (en) Open powder making steam warm air type boiler unit and power generation system thereof
CN204240347U (en) Superheat steam drying powder process type coal generating system
CN104132364A (en) Open powder making steam warm air type boiler unit and power generation system thereof
CN104359107A (en) Superheated steam drying powder making type coal-fired boiler machine unit
CN104132361A (en) Open powder making steam warm air type boiler unit and power generation system thereof
CN104329667A (en) Superheated steam drying power-making coal-fired power generation system
CN204176667U (en) The coal of fan mill powder process and the green electricity generation system of coal slime multifuel combustion
CN102798269B (en) Method and equipment for drying/cooling large particles of coal in guide duct type packed tower by cyclic utilization of superheated steam
CN204240387U (en) Superheat steam drying pulverized coal preparation system, coal-burning boiler unit and electricity generation system
CN104132360A (en) Open powder making steam warm air type boiler unit and power generation system thereof
CN104329666A (en) Coal-fired power generation system capable of drying superheated steam into powder
Yilmazoglu et al. 3E analysis of a solar assisted rotary type coal dryer
CN204084309U (en) The coal of fan mill and medium-speed pulverizer powder process and the green electricity generation system of coal slime multifuel combustion
Somov et al. Coal slurry drying process research
CN104165371B (en) The open weary gas heating type boiler controller system of powder process
CN204240385U (en) Superheat steam drying powder process type coal generating system
CN103836891B (en) A kind of Horizontal gas flow anhydration system for various moisture coal slime
CN204114896U (en) The coal of fan mill and air swept mill powder process and the green electricity generation system of coal slime multifuel combustion

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant