Graduation Comprehensive Practical Training Report
Title: Mine Ventilation Design
Major Class: High Mining Electricity 0831
Designer: Ren Danpeng
Supervisor: Liu Wennuan
May 27th 2011
Liaoyuan Vocational and Technical College
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Date of Reviewing: May 27th
Liaoyuan Vocational and Technical College
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Review Date: May 27, 2011
Liaoyuan Institute of Vocational Technology
Liaoyuan Institute of Vocational Technology
Graduation Design (Thesis) Defense Comments No.
Date: May 27, 2011
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Table of Contents
I. Content and Requirements of Mine Ventilation Design 5
(A) Ventilation during the Period of Mine Infrastructure 5
(B) Ventilation during the Period of Mine Production 5
(C) Contents of Mine Ventilation Design 6
(D) Requirements of Mine Ventilation Design 7
II. Preferred Mine Ventilation System 7
(I) Requirements of Mine Ventilation System 7
(II) Determination of Mine Ventilation System 8
III. Calculation of Mine Airflow 8
(I) Principles of Calculation of Mine Airflow 8
(II) Calculation of Mine Air Requirement 8
1. Calculation 8
2. Calculation of air demand in the face of excavation 11
3. Calculation of air demand in chambers 13
4. Calculation of air demand in other air passages 14
4. Calculation of the total resistance to ventilation in mines 15
(a) Principles of calculating the total resistance to ventilation in mines 15
(b) Calculation of the total resistance to ventilation in mines 15
V. Selection of Mine Ventilation Equipment 16
(A) Selection of Main Ventilators 17
VI. Estimated Mine Ventilation Costs 21
Introduction
Ventilation is an important link related to the safety of coal mine production. Ensure the stability and reliability of the ventilation system, to do with the mine production changes in the ventilation system instantly transformed and coordinated, strict control of tandem ventilation, strengthen the management of local ventilation, to put an end to the local ventilation fan unplanned power outages, so that the ventilation system is regular and reasonable, reliable and stable.
Mine ventilation design is an important part of the entire mine design content, is to ensure safe production of important links. Therefore, must be carefully considered, carefully designed, and strive to achieve the desired results.
Chapter I mine ventilation design content and requirements
The basic task of mine ventilation design is to establish a safe and reliable, technologically advanced and economical mine ventilation system. Mine ventilation design is divided into new or expanded mine ventilation design. For the new mine ventilation design, both the current needs to consider, but also to consider the possibility of long-term development. For the ventilation design of altered or expanded mines, it is necessary to make a detailed investigation of the original production and ventilation of the mine, analyze the problems of ventilation, consider the characteristics of mine production and development planning, make full use of the original shaft and ventilation equipment, and put forward a more perfect and practical ventilation design on the basis of the original. Regardless of the ventilation design of the new, rebuilt or expanded mine, must implement the Party's technical and economic policies, in accordance with the state promulgated mine safety regulations, technical regulations, design specifications and relevant regulations.
Mine ventilation design is generally divided into two periods, namely, the infrastructure period and the production period, respectively, the design calculation.
The first section of the mine infrastructure period of ventilation
The mine infrastructure period of ventilation refers to the construction of the process of digging shaft ventilation, that is, the excavation of the shaft (or flat), the bottom of the car park, underground chamber, the first level of transportation roadway and ventilation roadway ventilation. During this period, local ventilation fans are mostly used to locally ventilate the sole headway. Once the two shafts are connected and the main ventilator is installed, the main ventilator can be used to provide full-pressure ventilation to the excavated shafts, thus shortening the distance between the local ventilation of the rest of the shafts and the chambers.
Section 2: Ventilation during the production period
Ventilation during the production period refers to the ventilation after the mine is put into operation, including the ventilation of the whole mine development, mining and coal mining face and other shafts. This period of ventilation design, according to the length of the mine's production life, can be divided into two cases:
(1) when the mine service life is not long (about 15 to 20 years), only one ventilation design. After the mine reaches production, the ventilation resistance is the smallest for the mine ventilation easy period; mine ventilation resistance is the largest for the difficult period. According to the production of these two periods of design calculations, and select the ventilation of these two periods of ventilation are appropriate ventilation equipment.
(2) mine service life is longer, taking into account the ventilator equipment selection, the mine required air volume and wind pressure changes and other factors, and need to be divided into two periods of ventilation design. The first level is the first period, and the design calculations are carried out in detail for the two situations of easy and difficult ventilation in this period. The second phase of the ventilation design only do general principles of planning, but the mine ventilation system, should be based on the mine's entire production period of technical and economic factors, make a comprehensive consideration, so as to determine the ventilation system can be adapted to the reality of the production requirements, but also to take care of the long-term development of the production and changes in the situation.
The basic information required for mine ventilation design is as follows:
Topographic and geological maps of the mine; mine rock free silica (silicon), sulfur, radioactive substances and gas and harmful gas content; natural ignition propensity of the coal rock; coal dust explosivity; mine climatic conditions, including the annual maximum, minimum and average air temperature, temperature, geothermal heat deepening rate and perennial dominant wind direction, etc.; mine rock capacity, bulkiness, looseness coefficient, mud content and adhesion; whether there are old kilns and old lanes in the mine, their locations and existence; annual production, service life, development system, mining sequence, mining method; production distribution and operation arrangement, the number of working faces and the number of spare working faces; the number of various types of rock drills operating at the same time and their distribution; the maximum amount of explosives for blasting at the same time; the maximum number of people working at the same time, etc. etc.
Section 3: Contents of Mine Ventilation Design
(1) Determination of Mine Ventilation System
(2) Calculation of Mine Ventilation and Distribution of Air Volume
(3) Calculation of Mine Ventilation Resistance
(4) Selection of Ventilation Equipment
(5) Estimation of Mine Ventilation Costs
Additionally, according to the special conditions in different areas or mines Special conditions, but also need to be alert to the calculation of mine air temperature regulation (see Chapter 8 for details)
Section IV requirements for mine ventilation design
(1) sufficient fresh air to the underground workplace effectively, to ensure production and create good labor conditions;
(2) ventilation system is simple, stable air flow, easy to manage, with disaster resistance;
(3) ventilation system is simple, stable air flow, easy to manage, and have disaster resistance;
(4) selection of ventilation equipment p>
(3) when an accident occurs, the wind flow is easy to control, and it is easy for people to withdraw;
(4) there is an underground environment and safety detection system or detection measures in accordance with the regulations;
(5) the ventilation system's infrastructure investment is provincial, the operating costs are low, and the comprehensive economic benefits are good.
Chapter 2 Preferred Mine Ventilation System
Section 1 Requirements of Mine Ventilation System
(1) Each mine must have a complete independent ventilation system.
(2) The inlet shaft should be according to the frequency of wind throughout the year, and must be arranged in a place where it is not subject to the intrusion of dust, coal dust, dust, noxious gases and hot gases.
(3) skip hoisting wells or shafts equipped with tape conveyors should not be used as air intake wells, and if they are used as air intake wells, measures must be taken to meet the needs of safety.
(4) multi-fan ventilation system, under the premise of meeting the air volume according to the needs of the distribution, the main ventilators should be close to the working air pressure, when the difference in air pressure between the ventilators, should be reduced **** the air pressure of the air circuit, so that it does not exceed 30% of the air pressure of any one ventilator.
(5) For each production level and each mining area, return air lanes must be arranged and zonal ventilation must be practiced.
(6) There must be a separate fresh air flow to the underground blasting materials store, and the return air flow must be directly introduced into the main return air lane or the main return air lane of the mine.
(7) The underground charging room must be ventilated by a separate fresh air flow, and the return air flow should be introduced into the return air alley.
Section 2: Determination of Mine Ventilation System
Based on the conditions such as the amount of gas gushing out of the mine, the designed production capacity of the mine, the conditions of coal seams, the thickness of topsoil layer, the area of the well field, the temperature of the ground, the propensity of spontaneous combustion of coal seams, and taking into consideration of the mid- and late-stage production needs and so on, a number of technically feasible programs are put forward, and the ventilation system of the mine is determined through the optimization or the comparison of technical and economic conditions. The mine ventilation system should have strong anti-disaster ability, when the underground once a catastrophic accident occurs the selected ventilation system can control the disaster in the minimum range, and can quickly resume normal production.
Chapter 3: Calculation of mine air volume
Section 1: Principles of mine air volume calculation
Mine air volume shall be calculated according to the following requirements, and the maximum value shall be taken.
(1) Calculated according to the maximum number of people working at the same time in the underground, and the airflow per person per minute*** shall not be less than 4m?;
(2) Calculated according to the sum of the actual airflow required for coal mining, digging, refuge and others.
Section 2: Calculation of air demand in a mine
1. Calculation of air demand in a coal mining face
The amount of air in a coal mining face should be calculated according to the following factors to obtain the maximum value.
1) Calculation according to the amount of gas outflow
Qwi=100 Qgwi Kgwi
In the formula Qwi - the ith coal mining face requires air volume, m?/min
Qgwi - the ith coal mining face requires air volume, m?/min
Qgwi - the ith coal mining face requires air volume, m?/min
Qgwi - the ith coal mining face requires air volume, m? - the ith coal mining face gas absolute outflow, m?/min
Kgwi - the ith coal mining face due to uneven gas outflow standby air volume coefficient, which is the ratio of the maximum value of the absolute outflow of gas in the face and the average value. Production mines can make at least 5 day and night observations according to the normal production conditions of each working face, and derive 5 ratios and take the maximum value. Usually machine mining face Kgwi = 1.2 ~ 1.6; gun mining face Kgwi = 1.4 ~ 2.0; water mining face Kgwi = 2.0 ~ 3.0.
2) Calculation of the temperature of the incoming wind flow according to the face
The coal mining face should have a good weather conditions. The temperature of the incoming wind flow can be calculated according to the wind flow temperature prediction method. Its air temperature and wind speed should meet the requirements of Table 7-4-1.
Table 7-4-1 Corresponding Table of Air Temperature and Wind Velocity of Coal Mining Face
Air Temperature of Inlet Wind Stream of Coal Mining Face/°C Wind Velocity of Coal Mining Face/m?s-1
<15
15~18
18~20
20~23
23~26 0.3~0.5
0.5~0.8
0.8~1.0
1.0~1.5
1.5~1.8
Calculation of the required air volume of the coal mining face:
Qwi=60 Vwi Swi Kwi
Equation Vwi- - the wind speed of the ith coal mining face, according to the temperature of its incoming air flow from Table 7-4-1, m/s;
Swi - the effective ventilation section of the ith coal mining face, take the average of the effective section at the time of the maximum and minimum control of the roof, m2
Kwi -- length factor of the ith working face, can be selected according to Table 7-4-2.
Table 7-4-2 Table of wind volume coefficient for the length of coal mining face
Length of coal mining face/m Wind volume coefficient for the length of working face Kwi
<15
50～80
80～120
120～150
150～180
> 180 0.8
0.9
1.0
1.1
1.2
1.30~1.40
3) Calculated according to the amount of explosives used
Qwi=25×Awi
Equation 25- - air supply for each 1kg of explosives used, m3/min;
Awi - the maximum amount of explosives used in a single blast in the ith working face, kg;
4) Calculated according to the number of staff
Qwi=4×nwi
< p>Equation 4 - the minimum air volume per person per minute should be supplied, m3/min;nwi - the maximum number of people working at the same time in the ith coal mining face, one.
5) Calculation according to wind speed
Minimum airflow of each coal mining face according to the lowest wind speed:
Qwi≥60×0.25×Swi
Maximum airflow of each coal mining face according to the highest wind speed:
Qwi≤60×0.25×Swi
When there is a tandem ventilation of the coal mining face, the maximum airflow of each coal mining face shall be calculated according to one of the maximum airflow:
Qwi≤60×0.25×Swi
There are series connection of coal mining faces. When there is tandem ventilation in the coal mining face, it is calculated according to the maximum air demand of one of them. The air demand of the backup face is also calculated according to the above requirements and meets the requirements of gas, carbon dioxide, wind flow temperature and wind speed, and shall not be less than 50% of the air demand of the face when it is mined back.
2. Calculation of the air demand in the face of excavation
The air demand in the face of excavation of coal, semi-coal rock and rocky road should be calculated according to the following factors, and the maximum value should be taken.
1) Calculation according to gas outflow
Qhi=100×Qghi×Kghi
In the formula Qhi - the air requirement of the ith digging working face, m3/min;
Qghi. -The absolute gas outflow of the ith digging face, m3/min;
Kghi - uneven gas outflow and standby air volume coefficient of the ith digging face, generally 1.5-2.0.
2) Calculation according to the amount of explosive powder
Qhi=25×Ahi
In the formula 25 - the use of 1kg of explosives air supply, m3/min;
Ahi - the ith digging face of the maximum amount of explosives used in a blast, kg.
3) by the amount of explosives, the maximum amount of explosives used in a blasting, and the maximum amount of explosives used in a blasting. p>
3) According to the local ventilator suction air volume calculation
Qhi= ∑Qhfi×Khfi
In the formula ∑Qhfi - the i digging face at the same time operation of the local ventilator rated air volume of the sum. The rated air volume of various ventilators can be selected according to Table 7-4-3.
Khfi - in order to prevent the local ventilator suction circulating wind wind air reserve coefficient, generally take 1.2 ~ 1.3. 1.2 when there is no gas outflow in the air inlet roadway, when there is a gas outflow go to 1.3.
Table 7-4-3 rated air volume of various types of local ventilator
Fan Model Rated air volume/ m3?min-1
JBT-51(5.5KW)
JBT-52(11KW)
JBT-61(14KW)
JBT-62(28KW) 150
200
250
300
This is a good example of the type of local ventilation fan. p>4)Calculation by the number of staff
Qhi=4×nhi
In the formula nhi - the maximum number of people working at the same time in the ith digging face, people.
5) Calculation according to wind speed
Calculated according to the minimum wind speed, the minimum air volume of each rocky tunnel extinct working face:
Qhi ≥ 60×0.15×Shi
Minimum air volume of each coal tunnel or semi-coal tunnel digging face:
Qhi ≥ 60×0.25×Sdi
Calculated according to the maximum wind speed. Maximum airflow for each face:
Qhi≤ 60×4×Shi
Shi - the net area of the roadway of the ith face, m2.
3. Calculation of airflow for chambers
The amount of air supplied to each chamber should be calculated according to the different types of chambers. The calculation is based on different types of chambers:
1) Electromechanical chambers
For electromechanical chambers that generate a lot of heat, the calculation is based on the amount of heat generated by the electromechanical equipment operating in the chamber:
Qri= 3600 x ∑N x θ
ρ x Cp x 60 x Δt
Qhi--- the ith chamber. Qhi-air demand of the ith electromechanical chamber, m3/min;
∑N-the total power of electric motors (transformers) operating in the electromechanical chamber, kw;
θ-heat coefficient of the electromechanical chamber, which can be converted into a heat coefficient equivalent to that of electrical equipment operating in the chamber according to the actual investigation.
θ - the coefficient of heat generation, which can be determined by converting the actual heat generated by the operation of the mechanical equipment in the chamber into a coefficient equivalent to the amount of useless power generated by the capacity of the electrical equipment, and can also be determined in accordance with Table 7-4-4;
ρ - the density of the air, which is generally taken to be 1.2kg/m3;
Cp - the specific heat of the air at constant pressure, which is generally taken to be 1kJ/(kg?K);
Δt Δt-The temperature difference between the incoming and outgoing air streams of an electromechanical chamber, ℃.
Table 7-4-4 Coefficient of heat generation (θ) of electromechanical refuge
Name of electromechanical refuge Coefficient of heat generation
Air compressor room 0.20~0.23
Water pump room 0.01~0.03
Transformer substation, winch room 0.02~0.04
Transformer substation of the mining area and transformer refuge can be determined according to the empirical value. Determine the required air volume:
Qri=60~80 m3/min
2) Blasting material storage
Qri=4×V/60
In which V-volume of storage, m3
But the large-scale blasting material storage shall not be less than 100 m3/min, and small and medium-scale blasting material storage shall not be less than 60 m3/min.
Blasting material storage shall not be less than 100 m3/min. 60 m3/min.
3) Charging chamber
Calculated on the basis that the hydrogen concentration in the return airflow is less than 0.5%
Qri=200×qrhi
Qrhi - the amount of hydrogen produced by the ith charging chamber during charging, m3/min.
4. The air demand calculator for other air-using corridors
The air demand for each other corridor should be calculated according to the gas outflow and wind speed, and the maximum value should be used.
1) Calculation according to gas outflow
Qoi=133×Qgoi×kgoi
In the formula Qgoi - the absolute outflow of gas in the ith other air-using roadway, m3/min;
koi - the absolute outflow of gas in the ith other air-using roadway, m3/min;
koi - the absolute outflow of gas in the ith other air-using roadway, m3/min The standby coefficient of the ith other air-using lane with uneven gas outflow, generally kgoi=1.2~1.3.
2) Calculation according to the lowest wind speed
Qoi≥ 60×0.15×Soi
In the formula Soi-- The net section area of the ith other shaft, m2.
5. Calculation of the total air volume of the mine
The total air volume of the mine shall be calculated according to the sum of the actual air volume required for coal mining, excavation, chambers, and other locations:
Qm=(∑Qwt+∑Qht+∑Qrt+∑Qot)×km
In the formula ∑Qwt -- the sum of the air volume required for the coal mining face and the backup face, m3/min;
∑Qht -- the sum of the air volume required for the excavation face, m3/min;
∑Qrt -- sum of air requirements for chambers, m3/min;
∑Qot -- sum of air requirements for other air-using locations, m3/min.
km- - Coefficient of mine ventilation (including factors such as internal leakage and uneven air distribution in the mine), which can be taken as 1.15~1.25.
Chapter IV Calculation of Total Resistance of Mine Ventilation
Section I. Principles of Calculation of Total Resistance of Mine Ventilation
(1) The total resistance of mine ventilation should not be more than 2,940pa.
(2) The local resistance of the mine shaft, new mines (including the expansion of the expansion of the mine independent ventilation of the expansion area) should be calculated according to 10% of the frictional resistance of the shaft, the expansion of the mine should be calculated according to 15% of the frictional resistance of the shaft.
Section 2: calculation of total mine ventilation resistance
The total mine ventilation resistance refers to the wind flow from the inlet of the air shaft, to the return of the air shaft to the end of the frictional resistance and local resistance along a pathway (wind flow route) along the various branches of the sum of the resistance, or the total mine resistance, expressed in hm.
For two or more main ventilators work in the mine, the mine ventilation resistance should be calculated according to the system served by each main ventilator.
In the service life of the main ventilator, with the change of coal mining face and mining area succession, the total resistance of the ventilation system will also change. In order to make the main ventilator in the whole service period can meet the needs, and the main ventilator has a high operating efficiency, need to be in accordance with the development of mining layout and mining face succession arrangements, the main ventilator service period of different periods of the total resistance of the system to analyze the changes in the system, when according to the wind volume and the roadway parameters (cross-section, length, etc.) to determine the maximum total resistance directly route, you can be calculated in accordance with the route of resistance When the total mine resistance cannot be determined directly, several routes with the largest possible resistance should be selected for calculation and comparison, and then the total mine resistance for the period should be determined.
When the total resistance of the mine ventilation system is the smallest, it is called the period of easy ventilation. When the total resistance of the ventilation system is maximum, it is called the difficult period of ventilation. For the easy and difficult periods, the ventilation system should be drawn separately. The airflow is distributed according to the needs of the mining face and the chambers, and the total pressure of the mine is calculated from the resistance of each section of the airway.
In order to facilitate the calculation and checking, we can use the format of Table 7-4-5 to calculate the friction resistance hft of each section along the airflow route in the easy and difficult ventilation periods, and then calculate the total friction resistance hfe and hfd in the easy and difficult periods, and then multiply them by 1.1 (or 1.15 for expansion mines), to get the total pressure of the mines in the two periods hme and hmd.
The total pressure of the mines in the easy and difficult ventilation periods is calculated by the total pressure of the mines in the easy and difficult ventilation periods, which is calculated by the total friction resistance hfe and hfd in the easy and difficult ventilation periods.
The total resistance in the period of easy ventilation hme=(1.1~1.15)hfe
The total resistance in the period of difficult ventilation hmd=(1.1~1.15)hfd
The above two formulas hf is calculated according to the following formula:
hf= hfi
Sequence hfi= Qi2
Chapter V Mine Ventilation Equipment Selection
Section I. Mine ventilation equipment refers to the main ventilators and motors.
(1) Two sets of main ventilation equipment of equal capacity must be installed in the mine, with one set as a standby.
(2) Ventilation equipment should be selected to meet the changes in working conditions in each period of the first mining level, and to enable the ventilation equipment to operate efficiently for a long time. When the working conditions change greatly, the motor should be selected in stages according to the staging time of the mine and energy saving.
(3) Ventilator capacity should leave a certain margin, axial flow ventilator in the maximum design of negative pressure and air volume, the angle of operation of the wheel blades should be 5 ° less than the permissible range; centrifugal ventilator selection design speed should not be greater than 90% of the maximum permissible speed.
(4) into and out of the air shaft wellhead elevation difference of 150m or more, or into and out of the air shaft wellhead elevation is the same, but the depth of 400m or more, it is appropriate to calculate the natural wind pressure of the mine.
Section 2: Selection of Main Ventilator
(1) Calculation of Ventilator Air Volume Qf
Because of the external air leakage (i.e., air leakage from explosion-proof door of the wellhead and the counter-air door near the main ventilator, etc.), the air volume of the fan is greater than that of the mine air volume Qm
Qf=k Qm
Type: Qf - the working air volume of the main ventilator. - The working air volume of the main ventilator, m3/s;
Qm--mining air volume, m3/s;
K--wind loss coefficient of leakage, take 1.1 when the air shaft is not for hoisting, and take 1.1 when the air shaft is not for hoisting. skip well for return air take 1.15; return air and both lift personnel take 1.2.
(2) calculate the ventilator wind pressure
Ventilator full pressure Htd and the natural wind pressure of the mine HN *** with the same role to overcome the total resistance of the mine ventilation system hm, the ventilator accessory device (wind cave and diffuser) resistance hd and diffuser outlet kinetic energy loss Hvd. When the natural wind pressure and the ventilator wind pressure play the same role, the natural wind pressure is the same as the mine ventilation system. When the natural wind pressure is the same as the air pressure of the ventilator, "-" is taken; when the natural wind pressure is the opposite of the negative pressure of the ventilator, "+" is taken. According to the performance curve provided by the ventilator, by the following formula to find the ventilator wind pressure:
Htd=hm+hd+Hvd±HN
The centrifugal ventilator provides most of the full-pressure curve, while the axial flow ventilator provides most of the static pressure curve. Therefore, for extract ventilation mines:
Centrifugal ventilators:
Easy period Htd min=hm+hd+Hvd±HN
Difficult period Htd max=hm+hd+Hvd±HN
Table 7-4-5 Calculation table for ventilation resistance in mines
Periods Node No. Cul-de-sac name Support form a /
Ns2m-4 L/M U/M S/m2 S3/s6 R/
Ns2m-8 Q/
m3s-1 Q2/
m6s-2 hfi
/pa V/
ms-1
Easy period
hfi=∑hfi= pa
Difficult period
hfi=∑hfi= pa
Axial flow ventilator:
Easy period Htd min=hm+hd-HN
Difficult period Htd max=hm+hd+HN
Ventilation of the easy period in order to make the role of the natural wind pressure and the same role of the fan wind pressure, the ventilator has a higher
In order to make the natural wind pressure and ventilator wind pressure work in the same way during the easy ventilation period, the ventilator has a higher efficiency, so the natural wind pressure HN is subtracted from the resistance of the ventilation system; in order to make the capacity of the ventilator meet the natural wind pressure and ventilator wind pressure work in the reverse direction during the difficult ventilation period, so the natural wind pressure HN is added to the resistance of the ventilation system.
(3) Selection of the ventilator in the initial stage
According to the calculations of the ventilator in easy ventilation period of the mine, the Qf, the Hsd min (or Htd max), and the Qf, Hsd max (or Htd max) of the ventilator in the difficult period of mine ventilation on the characteristic curve of the ventilator, selected to meet the requirements of mine ventilation ventilator.
(4) the actual working point of the ventilator
Because according to the Qf, Hsd max (or Htd max) and Qf, Hsd min (or Htd max) to determine the working point, that is, the design working point is not a little bit in the selected characteristics of the curve of the ventilator, must be based on the work of the ventilator, to determine its actual working point.
1) Calculate the working wind resistance of the ventilator
With the static pressure characteristic curve:
Ssd min=
Ssd max=
With the full-pressure characteristic curve:
RTd min=
STd max=
2) Determine the actual working point of the ventilator
In the characteristic curve of the ventilator to do the ventilator working wind resistance curve, and the intersection of the wind pressure curve is the actual working condition point.
(5) Determine the type and speed of the ventilator
According to the working condition parameters of each ventilator (Qf, Hsd, η, N), compare the preliminary selection of ventilators in terms of technology, economy and safety, and finally determine the type and speed of the ventilator that meets the requirements of mine ventilation, advanced technology, high efficiency and low operating costs.
(6) Motor selection
1) The input power of ventilator is calculated according to the easy and difficult ventilation period, and the required input power of ventilator is Nmin and Nmax respectively.
Nmin= Qf Hsd min/1000ηs Nmax= Qf Hsd max/1000ηs
or Nmin= Qf Htd min/1000ηt Nmax= Qf Htd max/1000ηt
Where ηt and ηs are the ventilator full-pressure efficiency and static-pressure efficiency, respectively;
2) Number and type of motors
When Nmin ≥ 0.6Nmax, one motor can be selected, and the power of the motor is
Ne=Nmax? ke/(ηeηtr)
When Nmin<0.6Nmax, two motors can be selected, and their power is
In the early stage Nemin= ?ke/(ηeηtr)
Later stage is calculated according to Ne=Nmax?ke/(ηeηtr).
The formula ke - motor capacity standby coefficient, ke = 1.1 ~ 1.2
ηe - motor efficiency, ηe = 0.9 ~ 0.94 (large motors take the higher value)
ηtr The advantage is that in low load operation, can be used to improve the power factor of the power grid, so that the mine economic power; disadvantage is that the purchase and installation of this motor is higher.
Chapter 6 Estimating Mine Ventilation Costs
Ton of coal ventilation cost is an important economic indicator of ventilation design and management. Statistical analysis of the composition of the cost is to explore the cost reduction to improve economic efficiency indispensable basic information.
Ton of coal ventilation costs mainly include the following costs:
1. Electricity (W1)
Ton of coal ventilation electricity costs for the main ventilator annual consumption of electricity and underground auxiliary ventilator, local ventilator electricity costs and divided by the annual output, can be calculated by the following formula:
W1 = (E + EA) × D/T
Where E -- annual power consumption of the main ventilator, the design is calculated using the following formula:
Ventilation easy period and difficult period*** when selecting a motor,
E=8760 (Nemin+ Nemax)/(keηvηw)
When selecting two motors
E=4380 (Nemin+ Nemax)/(keηvηw)
Equation D--electricity price, yuan/kw?h
T--annual output of the mine, t;
EA -- annual power consumption of local ventilation fan and auxiliary ventilation fan;
ηv -- transformer efficiency, can be taken as 0.95
ηw -- cable power transmission efficiency, depending on the cable length and cable loss per meter, in the range of 0.9 to 0.95 selected.
2. Depreciation of equipment
The depreciation of ventilation equipment is related to the number of equipment, cost and service life can be calculated in Table 7-4-6.
Ton of coal depreciation of ventilation equipment W2 for
W2 = (G1 + G2)/T
Table 7-4-6 ventilation cost calculation table
Sequence
No.
Equipment name
Calculation unit
Quantity Total cost
Total Service
Years of service
Years
Limit Depreciation of basic investment Depreciation of major repairs
Remarks
Unit cost Equipment cost Transportation and installation cost
3. Material consumption cost
Includes the material cost of all kinds of ventilation structures, lubricating oil cost of ventilators and electric motors, and the cost of dust prevention and other facilities. Ventilation material consumption cost W3 per ton of coal is:
W3=C/T
In the formula C--Total material consumption cost, yuan/a.
4. Ventilation staff wage cost
Mine ventilation staff, the total annual wage is A (yuan), then a ton of coal wage The cost W4 is
W4= A/T
5. Depreciation and maintenance costs of shaft works dedicated to ventilation
Depreciated to a ton of coal is W5.
6. Purchase cost of ventilation instrumentation per ton of coal and the cost of maintenance W6
The total cost of ventilation of the mine for each ton of coal mined is W
W= W1 +W2+ W3+ W4+ W5+ W6 mine
Conclusion
Three years of study has come to an end, I through three years of systematic study, so that I have mastered the solid basic theory and systematic expertise, but also to make a great improvement in my business level, and all of this is due to the Liaoyuan Vocational and Technical Institute of the deep teachings of the teachers and enthusiastic encouragement. On the occasion of graduation, I would like to thank all the teachers who educated me and cared about me in the past three years, they gave me the most powerful help and encouragement during my study, so that I can successfully complete my studies, for which I express my heartfelt thanks! This project is completed under the careful guidance of my supervisor, Prof. Warm Liu. Over the past half a year, Prof. Liu has asked me many times about the progress of the project and helped me to develop my research ideas. Prof. Liu has set an example for me with his rigorous and realistic attitude, high professionalism, diligent work style and bold and innovative spirit. I would like to express my sincere gratitude and high respect to Prof. Liu.
References
(1)Mine Ventilation and Safety Author: He Tingshan 2009
(2)Textbook of Coal Mining Technology Specialization and Specialized Groups Author: Yu Xiaofeng, Liu Qizhi