CN105170331A - Method for determining inlet flue gas temperature of low-low temperature electrostatic precipitator - Google Patents

Abstract

The invention discloses a method for determining the inlet flue gas temperature of a low-low temperature electrostatic precipitator. The inlet flue gas temperature is at least 5 DEG C lower than the temperature of an acid dew point, and the inlet flue gas temperature is higher than 85 DEG C and lower than 95 DEG C. The method has the advantages that a selection method of the most important parameter method in type selection of the low-low temperature electrostatic precipitator is provided firstly; the inlet flue gas temperature is a decisive parameter for properties of the energy saving effect, the dust removal efficiency, whether ash blocking occurs and the like of the low-low temperature electrostatic precipitator; if the temperature is too low, the mobility of ash becomes poor, and blocking is caused; if the temperature is too high, acid mist adhering to the surface of dust cannot be formed by sulfur trioxide in flue gas; a foundation is laid for application and popularization of the domestic low-low temperature electrostatic precipitator.

Description

Low low temp. electric deduster entrance flue gas temperature defining method

Technical field

The present invention relates to low low temp. electric deduster entrance flue gas temperature defining method.

Background technology

Current low low temp. electric deduster is mainly used in Japan, foreign applications display efficiency of dust collection is higher than conventional electric cleaner, the still prematurity of domestic low low temp. electric dust catcher select designing technique, for the computational methods that the impact of Coal rank on low low temp. electric deduster is not determined, the computational methods that especially low low temp. electric deduster entrance flue gas temperature is not determined.Flue gas acid dew point temperature is the call parameter of low low temp. electric dust catcher select design, and the computational methods of acid dew-point temperature, the defining method of entrance flue gas temperature and influence factor, domestic all do not have method, constrains low low temp. electric deduster application and development at home.

The entrance flue gas temperature of low low temp. electric deduster does not still have defining method at present.Flue-gas temperature is too high will affect efficiency of dust collection and SO ₃clearance, flue-gas temperature is too low will be caused excessive corrosion and reduce the mobility of ash and cause the even stifled ash of knot ash.

Summary of the invention

The object of the present invention is to provide low low temp. electric deduster entrance flue gas temperature defining method, effectively can solve and cannot determine entrance flue gas temperature, cause efficiency of dust collection and SO ₃low or the corrosion of clearance and the problem of grey poor fluidity.

In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions: low low temp. electric deduster entrance flue gas temperature defining method, entrance flue gas temperature is lower than acid dew-point temperature at least 5 DEG C, and entrance flue gas temperature is greater than 85 DEG C and is less than 95 DEG C.

Preferably, Calculation of Acid Dew Point Temperature method adopts following formula to carry out calculating entrance flue gas temperature t _sld,

$t_{sld}=t_{ld}+\frac{\mathrm{\β}\×{S_{ZS}}^{1/3}}{{1.05}^{({\mathrm{\α}}_{fh}\×A_{ZS})}}$

Wherein t _sldunit DEG C; S _zSfor fuel conversion sulfur percentage; A _zSfor fuel conversion percent ash;

α _fhfor flying dust share; β is the excess air coefficient of furnace outlet; t _ldfor pure water vapor dew-point temperature.

Preferably, described t _ldcomputing formula as follows: t _ld=-1.2102+8.4064 × φ H ₂o-0.4749 × (φ H ₂o) ²+ 0.01042 × (φ H ₂o) ³wherein Φ H ₂o is steam volume fraction in flue gas, unit vol%.

Preferably, the span of described β is 121 ~ 129.

Preferably, the value of described β is 125.

Preferably, for powder coal stove α _fhspan be 0.8 ~ 0.9.

Compared with prior art, advantage of the present invention is: this method takes the lead in providing the system of selection of most important parametric technique in the type selecting of low low temp. electric deduster, entrance flue gas temperature is low low temp. electric deduster energy-saving effect, efficiency of dust collection, whether the decisive parameter of the performances such as stifled ash occurs, the mobility of the too low ash of temperature can be deteriorated, result in blockage, sulfur trioxide in the too high flue gas of temperature cannot form acid mist and stick to dust surface, for the application of domestic low low temp. electric deduster and popularization lay the foundation.

Detailed description of the invention

Low low temp. electric deduster entrance flue gas temperature defining method, entrance flue gas temperature is lower than acid dew-point temperature at least 5 DEG C, and entrance flue gas temperature is greater than 85 DEG C and is less than 95 DEG C, and Calculation of Acid Dew Point Temperature method adopts following formula to carry out calculating entrance flue gas temperature t _sld,

$t_{sld}=t_{ld}+\frac{\mathrm{\β}\×{S_{ZS}}^{1/3}}{{1.05}^{({\mathrm{\α}}_{fh}\×A_{ZS})}}$

Wherein t _sldunit DEG C;

S _zSfor fuel conversion sulfur percentage;

A _zSfor fuel conversion percent ash;

α _fhfor flying dust share, powder coal stove α _fhspan be 0.8 ~ 0.9;

β is the excess air coefficient of furnace outlet, and span is 121 ~ 129;

T _ldfor pure water vapor dew-point temperature, can be drawn by following formulae discovery, also can table look-up 1

T _ld=-1.2102+8.4064 × φ H ₂o-0.4749 × (φ H ₂o) ²+ 0.01042 × (φ H ₂o) ³wherein Φ H ₂o is steam volume fraction in flue gas, unit vol%.

Table 1 steam dew-point hygrometer

Entrance flue gas temperature:

(1) to acid dew point

Flue-gas temperature is only had to be down to below acid dew point, the most of SO in flue gas ₃sulfuric acid mist could be converted in heat regenerator and stick to dust surface, while improving efficiency of dust collection, removing the most of SO in flue gas ₃.In actual moving process, the acid dew point of boiler fired coal also can change with coal-fired difference, and the theory calculate of acid dew point is also an estimated value.So generally, for ensureing that low low temp. electric deduster runs below acid dew point, flue-gas temperature should lower than acid dew-point temperature calculated value 5 DEG C ~ 10 DEG C.When flue-gas temperature allowance is too small, when namely low low temp. electric deduster entrance flue gas temperature is too close to acid dew-point temperature, SO may be there is ₃uncooled and escape into the phenomenon of condensation in electric cleaner in heat regenerator, make electric cleaner or its upstream device there is corrosion risk.

(2) lowest temperature

When flue-gas temperature is lower than 80 DEG C, the mobility of ash can become very poor, and very easily produce ash bucket and block up grey situation, bottom ash-transmission system also can have problems simultaneously; In addition, during cigarette temperature too low (as lower than 85 DEG C), the investment of heat regenerator can significantly be risen, and economy is deteriorated; May go out to manage hydrochloric acid condensation in addition and produce more serious corrosion risk, therefore, low low temp. electric deduster flue-gas temperature should not lower than 80 DEG C.

(3) downstream desulphurization system optimum temperature is adapted to

Low low temp. electric deduster, in whole smoke gas treatment route, not only can improve the efficiency of wet desulphurization, can save wet desulphurization utility rate of water simultaneously, avoid SO ₃dewing corrosion.

In sum, consider electric cleaner temperature drop 3 DEG C ~ about 5 DEG C, in detailed programs, above three factors need be considered, thus determine the determined value of entrance flue gas temperature, general selection low low temp. electric deduster entrance flue gas temperature is 85 DEG C ~ 95 DEG C, and concrete numerical value can be drawn by formulae discovery of the present invention.

The foregoing is only specific embodiments of the invention, but technical characteristic of the present invention is not limited thereto, any those skilled in the art is in the field of the invention, and the change done or modification are all encompassed among the scope of the claims of the present invention.

Claims (6)

1. low low temp. electric deduster entrance flue gas temperature defining method, is characterized in that: entrance flue gas temperature is lower than acid dew-point temperature at least 5 DEG C, and entrance flue gas temperature is greater than 85 DEG C and is less than 95 DEG C.

2. low low temp. electric deduster entrance flue gas temperature defining method as claimed in claim 1, is characterized in that: Calculation of Acid Dew Point Temperature method adopts following formula to carry out calculating entrance flue gas temperature t _sld,

$t_{sld}=t_{ld}+\frac{\mathrm{\β}\×{S_{ZS}}^{1/3}}{{1.05}^{({\mathrm{\α}}_{fh}\×A_{ZS})}}$

Wherein t _sldunit DEG C; S _zSfor fuel conversion sulfur percentage; A _zSfor fuel conversion percent ash; α _fhfor flying dust share; β is the excess air coefficient of furnace outlet; t _ldfor pure water vapor dew-point temperature.

3. low low temp. electric deduster entrance flue gas temperature defining method as claimed in claim 2, is characterized in that: described t _ldcomputing formula as follows:

t _ld＝-1.2102+8.4064×φH ₂O-0.4749×(φH ₂O) ²+0.01042×(φH ₂O) ³

Wherein Φ H ₂o is steam volume fraction in flue gas, unit vol%.

4. low low temp. electric deduster entrance flue gas temperature defining method as claimed in claim 2, is characterized in that: the span of described β is 121 ~ 129.

5. low low temp. electric deduster entrance flue gas temperature defining method as claimed in claim 4, is characterized in that: the value of described β is 125.

6. low low temp. electric deduster entrance flue gas temperature defining method as claimed in claim 2, is characterized in that: for powder coal stove α _fhspan be 0.8 ~ 0.9.