RU2056010C1 - Slurry combustion preparation method - Google Patents

Abstract

FIELD: thermal power stations. SUBSTANCE: coal slurry combustion preparation method involves mixing slurry with solid coal phase in homogenizer while checking its flow rate prior to supplying mixture obtained to sprayer. Method is distinguished by that before mixing, effective viscosity, moisture content, and volume flow of slurry and moisture content of solid coal phase are determined, viscosity of mixture obtained is specified according to spraying conditions, and solid phase flow rate is calculated using formula given in description of invention. EFFECT: improved quality and caloric value of coal-slurry fuel. 1 dwg

Description

 The invention relates to energy and can be used in thermal power plants.

 A known method of preparation for burning coal suspensions, comprising mixing suspensions with a solid coal phase in a homogenizer with simultaneous control of the flow of the latter before feeding the resulting mixture to a spray device.

 The disadvantage of this method is the lack of control over the parameters coming into the mixing of the components, as a result of which the resulting suspension does not have optimal fuel properties.

 The aim of the invention is to improve the quality and calorific value of coal-suspension fuel.

где ΔC

допустимое увеличение концентрации угольной суспензии;
К эмпирический коэффициент.This goal is achieved due to the fact that in the known method of preparing for burning coal suspensions, which involves mixing suspensions with a solid carbon phase in a homogenizer while controlling the flow of the latter before feeding the resulting mixture to a spray device, before mixing, determine the effective viscosity μ _o , humidity W _о and the volumetric flow rate G _{about the} suspension, humidity W _{Δ of the} solid carbon phase, are set by the viscosity μ of the resulting mixture from the spraying conditions, and the flow rate G _{Δ of the} solid phase is calculated by the formula
G _Δ = G _o

where ΔC

allowable increase in the concentration of coal suspension;
K empirical coefficient.

 The drawing shows a diagram of an installation for preparing for burning coal slurry entering the place of use (for example, at a thermal power plant) through a pipeline.

 The main coal pipe 1 is equipped with a block 2 of instruments that measure the parameters of the incoming suspension, and is connected to a homogenizer 3, where a solid coal phase (dust) enters from the coal storage 4 through block 5 of dust preparation and evacuation. The pipeline 6 is also equipped with a block 7 of devices for measuring the parameters of the coal mixture.

 The coal suspension ready for combustion obtained in the homogenizer 3 enters the storage tank 8, from where it is fed by pump 9 to the spraying devices of boiler units, for example, TPP furnaces.

The coal suspension coming through the pipeline has the initial parameters: effective viscosity μ _o , humidity W _o , ash content A _o , sulfur content S _o , while the volumetric flow rate of the suspension is G _o . All flow parameters are continuously monitored by a block of 2 devices. Coal storage 4 of TPP contains coal with the following properties: humidity W _Δ , ash A _Δ, sulfur content S _Δ , and these parameters are also controlled at the entrance to the homogenizer 3. The volumetric flow rate of solid fuel (dust) has a value G _Δ , which is set depending on the required at the exit from the homogenizer 3 parameters of the suspension.

As a result of mixing coal suspension and coal dust, fuel is formed with a higher concentration C of coal and, accordingly, with a reduced moisture content W, and ash content A and sulfur content S of the resulting fuel are an intermediate value from the initial data. The total volumetric flow rate G of the resulting fuel is equal to the sum of the costs of the suspension G _about and coal dust G _Δ .

The consumption of coal dust added to the coal suspension, and, accordingly, the increase in the concentration of solid in the fuel, are unambiguously determined from the condition of the value of the effective viscosity μ of the resulting fuel acceptable for the spraying devices used. Thus, the fuel supplied to the spray must have an effective viscosity
μ A · exp (K · C) (1) where A and K are empirical coefficients characterizing a specific type of fuel and spraying conditions;
With the concentration of solid in the fuel.

(2) где коэффициент K для водоугольного топлива составляет 33,4 (из каменных углей): 18,8 (из бурых углей); 15,5 спиртоугольного топлива.If the value of the effective viscosity μ _{o of the} initial suspension received through the pipeline is known, we can determine the allowable increase in the concentration of fuel in the homogenizer
μ _o = A • exp (K • C _o ) (1 ′) ΔC

(2) where the K coefficient for water-carbon fuel is 33.4 (from hard coal): 18.8 (from brown coal); 15.5 alcohol fuel.

где I теплота сгорания сжигаемого топлива;
I_o теплота сгорания исходной суспензии;
Q_с теплота сгорания сухого угля;
Q_п теплота испарения воды.In this case, the relative increase in the calorific value (calorific value) of the fuel is determined as follows:

where I is the calorific value of the combusted fuel;
I _{o the} calorific value of the initial suspension;
Q _{with the} calorific value of dry coal;
Q _{p the} heat of evaporation of water.

The volumetric flow rate of the pulverized coal duct G _Δ added to the suspension is determined from the conditions
GG _o + G _Δ , (4) where G is the total volumetric flow rate,
GW G _o W _o + G _Δ W _Δ , (5) where GW is the total amount of moisture in the fuel,
WW _o Δ C, (6) where W is the moisture content of the final product.

G_o

(7)
Аналогичным образом можно проконтролировать параметры получаемого топлива по зольности и сернистости и при необходимости откорректировать величину расхода G_Δ.G _Δ = G _o

G _o

(7)
Similarly, it is possible to control the parameters of the resulting fuel for ash and sulfur content and, if necessary, to adjust the flow rate G _Δ .

(8)
S

(9)
П р и м е р 1. Исходная суспензия, поступающая по трубопроводу, имеет следующие параметры:
μ_o 500 сПз W_о 0,4
A_о 0,15 S_о 0,012
G_о 100 кг/с Q_с 27,2 МДж/кг
Q_п 2,26 МДж/кг.A

(8)
S

(9)
PRI me R 1. The initial suspension coming through the pipeline has the following parameters:
μ _o 500 cps W _about 0.4
A _about 0.15 S _about 0.012
G _about 100 kg / s Q _s 27.2 MJ / kg
Q _p 2.26 MJ / kg.

0,0415 W=0,3585 а допустимый расход угольной пыли
G_Δ=G_o

100 (кг/с)

16,05 (кг/с)
G G_o + G_Δ=116,05 (кг/c)
Относительное увеличение теплоты сгорания (калорийности) топлива составит в соответствии с (3):

0,0793
Контрольный расчет зольности и сернисто- сти показывает:
A

0,1403
S

0,0112
т.е. A_Δ< A < A_o и S_Δ< S < S_o.Characteristics of coal in stock:
W _Δ = 0.1 A _Δ 0.1 S _Δ 0.008
The permissible increase in the concentration ΔС with the permissible value of the effective viscosity of the combusted fuel μ 2000 cPz will be:
ΔC

0.0415 W = 0.3585 a permissible consumption of coal dust
G _Δ = G _o

100 (kg / s)

16.05 (kg / s)
GG _o + G _Δ = 116.05 (kg / s)
The relative increase in the calorific value (calorific value) of the fuel will be in accordance with (3):

0,0793
The control calculation of ash and sulfur content shows:
A

0.1403
S

0.0112
those. A _Δ <A <A _o and S _Δ <S <S _o .

100

26,18 (кг/с)
G G_o + G_Δ= 126,18 (кг/с)
A

0,158
S

0,0125
т.е. A_о < A < A_Δ и S_о < S < S_Δ

0,0793
При превышении значений S выше допустимых по условиям сжигания возможно введение специальных добавок (например, соединений кальция) уже на стадии гомогенизации, что исключает необходимость транспортировать суспензию вместе с добавками и снижает энергозатраты на транспорт.PRI me R 2. If, on the contrary, the coal in the warehouse has a higher ash and sulfur content than the initial suspension, and high humidity
A _Δ = 0.18 S _Δ = 0.014 W _Δ 0.20
Δ C 0.0415 WW _about Δ C
0.4 -0.0415 = 0.3585
G _Δ = G _o

one hundred

26.18 (kg / s)
GG _o + G _Δ = 126.18 (kg / s)
A

0.158
S

0.0125
those. A _about <A <A _Δ and S _about <S <S _Δ

0,0793
If the S values are higher than those allowed by the combustion conditions, it is possible to introduce special additives (for example, calcium compounds) already at the homogenization stage, which eliminates the need to transport the suspension together with additives and reduces energy costs for transport.

 Thus, according to the results of measuring the properties and flow rate of the slurry coming through the pipeline, and when the properties of the coal stored in the warehouse are known, and also based on the set limit value of the viscosity of the fuel supplied for combustion, the possible flow rate of coal dust added to the suspension is determined, and the characteristics are controlled fuel received: μ W, AS

 Thanks to this process of preparing for burning coal slurry fed to thermal power plants via the main pipeline, the heat of combustion of the fuel increases, burner performance improves due to the stabilization of the fuel properties, the reserve complex for the dust preparation of thermal power plants is activated, it is possible to influence the properties of the fuel with the help of additives immediately before burning and exclude them pipeline transportation.

Claims (1)

METHOD FOR PREPARING FOR COMBUSTION OF COAL SUSPENSIONS, comprising mixing suspensions with a solid carbon phase in a homogenizer while controlling the flow of the latter before feeding the resulting mixture into a spray device, characterized in that before mixing the effective viscosity μ _o , humidity W ₀ and suspension volume flow rate G _{0 are} determined , humidity W _{Δ of the} solid carbon phase, are set by the viscosity of the resulting mixture m from the spraying conditions, and the consumption of the solid carbon phase is calculated by the formula

Where

allowable increase in the concentration of coal suspension;
K is an empirical coefficient.

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