CN105423312A - Method of treating coal chemical industry saliferous sewage based on combustion in furnace - Google Patents

Abstract

The invention discloses a method of treating coal chemical industry saliferous sewage based on combustion in furnace and belongs to the technical field of sewage treatment. The method comprises the steps that the saliferous sewage is firstly subjected to treatment by a condensing apparatus to form saliferous sewage of at least 5% of salt concentration; the concentrated saliferous sewage is ejected into a hearth for blending combustion; the maximum ejection amounts of saliferous sewage of different salt concentrations are calculated by comprehensively considering fouling and slagging as well as high-temperature chlorine corrosion; and various organic matters and massive inorganic salt in the saliferous sewage are effectively treated in a high-temperature combustion environment, so the large-scale treatment of the saliferous sewage is realized. According to the method of treating coal chemical industry saliferous sewage based on combustion in furnace, under the condition of ensuring the safe and economic operation of a boiler and realizing acceptable thermal efficiency decrease of the boiler, the treatment cost of the coal chemistry industry saliferous sewage is greatly reduced; and the method is suitable for treating coal chemical industry sewage with high alkali metal content.

Description

A kind of method based on stove combustion process Coal Chemical Industry saline sewage

Technical field

The present invention relates to a kind of method based on stove combustion process Coal Chemical Industry saline sewage, coal chemical industry sewage is directly sprayed into boiler to process, and consider Slagging, high temperature chloride corrosion, calculate the maximum straying quatity of variable concentrations saline sewage, to ensure the safety and economic operation of boiler, belong to technical field of sewage.

Background technology

Coal Chemical Industry needs to consume a large amount of water, 130 kinds are reached containing all kinds of organic matter being difficult to degrade in typical case's coal chemical industry sewage, its main component comprises COD (2000 ~ 4000mg/L), ammonia nitrogen (200 ~ 500mg/L), total phenol mass concentration is 300 ~ 1000mg/L, volatile phenol mass concentration is 50 ~ 300mg/L, simultaneously also containing poisonous and harmful substances such as cyanide, rhodanide, polycyclc aromatic compound and heterocyclic compounds.In addition, also containing all kinds of soluble inorganic salt (crystal salt) in coal chemical industry sewage, concrete content depends on the mineral composition in coal, but it is main based on alkali metal salts such as sodium salts, although above-mentioned inorganic salts output is larger, but purity is not high, commercial value is very low, about the research of collecting ash and slagging scorification shows, the alkali-metal existence such as sodium has material impact to boiler Slagging, and is the major reason reducing coal ash sintering temperature, accelerate coal ash sintering rate and increase sintering strength and cause wall erosion.The scale being mixed with various organic saline sewage is treated as the major obstacle affecting Coal Chemical Engineering Project construction and performance driving economy.

Summary of the invention

The object of this invention is to provide a kind of method based on stove combustion process Coal Chemical Industry saline sewage; coal chemical industry sewage is sprayed into boiler furnace; in high-temp combustion environment, effectively can dispose each type organic in coal chemical industry sewage, the scale process problem of saline sewage can be solved again.

Technical scheme of the present invention is as follows:

Coal chemical industry sewage is directly sprayed into boiler to process, it is characterized in that the concentrated saline sewage obtained through concentrator sprays into burner hearth by pipeline and auxiliary equipment.Concentrated saline sewage sprays into burner hearth position and arranges according to boiler type and actual demand, to CFBB, from furnace roof or Secondary Air At The Height, concentrated saline sewage is sprayed into burner hearth; To pulverized-coal fired boiler, below secondary air bellow top or burnt wind, concentrated saline sewage is sprayed into burner hearth.Concentrated saline sewage spray into burner hearth position can one place arrange or many places arrange and be not limited to advised position.

Coal Chemical Industry saline sewage is maximum to be sprayed into gauge to calculate process as follows:

The maximum straying quatity of saline sewage of variable concentrations:

Q＝M _salt/w①

In formula:

M _salt＝min(C _sm _salt,0.003m _coalC _cl,0.0148A _arm _coal)②

Wherein, Q is the maximum straying quatity of Coal Chemical Industry saline sewage; M _saltfor considering the limit content spraying into alkali metal salt in saline sewage that contamination, chlorine corrosion and experimental data obtain; C _s=(N ₁/ N ₂+ 0.5N ₃/ N ₄), N ₁for Na ₂the mass fraction of Na element in O, N ₂represent the Na element mass fraction in sodium salt in saline sewage, N ₃for K ₂the mass fraction of K element in O, N ₄represent the mass fraction of K element in sylvite in saline sewage; m _saltfor only consider that Slagging risk obtains with Na ₂o+0.5K ₂o be composition spray into alkali metal salt maximum level in saline sewage; C _cl=1/N _cl, wherein N _clrepresent the ratio of Cl element and alkali metal salt in saline sewage; m _coalrepresent steam coal consumption; A _arrepresent pit ash content; W represents alkali metal salt mass fraction in Coal Chemical Industry saline sewage.

When only consider that Slagging risk obtains with Na ₂o+0.5K ₂o is that the alkali metal salt maximum level following formula in saline sewage that sprays into of composition calculates:

$m_{\mathrm{salt}}=\frac{m_{\mathrm{coal}}{A}_{\mathrm{ar}}(s_{\mathrm{lim\; it}}-s)}{100(100-s_{\mathrm{lim\; it}})}$ ③

Sodium salt equivalent S=Na in ash ₂o+0.5K ₂o (%); The computational methods of sodium salt limit fixed value in coal:

R＝(A-BV _daf)(Na ₂O+CK ₂O)<R _limt④

Coal ash sodium salt limiting value is S _limit=R _limit/ (A-BV _daf) (%); m _coalfor boiler coal consumption; R is sodium salt limit fixed value in coal; R _limitfor the limiting value of sodium salt limit fixed value in coal, when R is higher than R _limittime, think that sodium salt exceedes maximum crystallized ability in coal, will there is dust stratification contamination problems in this coal ash in boiler operatiopn.

Constant A, B weigh coal affects size model parameter on sodium salt fixed pole limit value; C weighs K ₂the equivalent constant that O affects sodium salt fixed pole limit value; V _daffor dry ash free basis volatile matter content; Na ₂o and K ₂o represents the mass fraction that this two oxides is shared in coal ash respectively.

In technique scheme, the mode that the saline sewage after concentrated sprays into burner hearth is: to CFBB, from furnace roof or Secondary Air At The Height, concentrated saline sewage is sprayed into burner hearth; To pulverized-coal fired boiler, below secondary air bellow top or burnt wind, concentrated saline sewage is sprayed into burner hearth.

The present invention has the following advantages and high-lighting effect: 1. Coal Chemical Industry saline sewage is sprayed into boiler by the present invention under the condition ensureing safe operation of the boiler, the each type organic in saline sewage and a large amount of inorganic salts are effectively disposed in high-temp combustion environment, thus solve the scale process problem of saline sewage, practical; 2. the present invention in acceptable situation, greatly reduces coal chemical industry sewage processing cost good economy performance not affecting boiler normal operational energy and boiler thermal output declines; 3. this method considers the Slagging risk that Boiler Mixed Burning causes, and chlorine corrosion risk and experimental data, finally obtain the maximum straying quatity of saline sewage of variable concentrations, have good theoretical foundation; 4. provide Coal Chemical Industry saline sewage processing method, according to actual conditions, select to spray into the saline sewage that salt concentration is at least 5%, method is simple; 5. little to boiler improvement, conveniently, operating cost is low for everyday devices maintenance and replacing.

Accompanying drawing explanation

Fig. 1 is provided by the invention with the structure diagram of high saliferous demineralized water for the Natural Circulation injection boiler of feedwater.

1-saline sewage concentrator; 2-water pump; 3-flow valve; 4-the first atomizer; 5-the second atomizer; 6-boiler.

Detailed description of the invention

Principle of the present invention, concrete structure and preferred forms is further illustrated below in conjunction with accompanying drawing.

Coal chemical industry sewage is directly sprayed into boiler, the concentrated saline sewage of certain flow sprays in boiler 6 through the first atomizer 4 or the second atomizer 5 by water pump 2 and flow valve 3 by the concentrated saline sewage obtained through concentrator 1, according to actual conditions, can select to spray into the saline sewage that salt concentration is not less than 5%, concentrated saline sewage sprays into burner hearth position and arranges according to boiler type and actual demand, to CFBB, from furnace roof or Secondary Air At The Height, concentrated saline sewage is sprayed into burner hearth; To pulverized-coal fired boiler, below secondary air bellow top or burnt wind, concentrated saline sewage is sprayed into burner hearth.Concentrated saline sewage spray into burner hearth position can one place arrange or many places arrange and be not limited to advised position.

The maximum straying quatity of Coal Chemical Industry saline sewage is by calculating.Coal Chemical Industry saline sewage treating capacity mainly restricts by alkali metal content, and analyze alkali metal occurrence form in saline sewage, 4. 3. through type calculate with formula with Na ₂o+0.5K ₂o be composition spray into alkali metal salt limit content m in saline sewage _salt, consider contamination, chlorine corrosion and experimental data and obtain boiler and spray into alkali metal salt limit content M in saline sewage _salt, calculated the maximum straying quatity of saline sewage of variable concentrations by alkali metal salt concentration, computational process is as follows:

The maximum straying quatity of saline sewage of variable concentrations:

Q＝M _salt/w①

In formula:

M _salt＝min(C _sm _salt,0.003m _coalC _cl,0.0148A _arm _coal)②

Wherein, Q is the maximum straying quatity of Coal Chemical Industry saline sewage; M _saltfor considering the limit content spraying into alkali metal salt in saline sewage that contamination, chlorine corrosion and experimental data obtain; C _s=(N ₁/ N ₂+ 0.5N ₃/ N ₄), N ₁for Na ₂the mass fraction of Na element in O, N ₂represent the Na element mass fraction in sodium salt in saline sewage, N ₃for K ₂the mass fraction of K element in O, N ₄represent the mass fraction of K element in sylvite in saline sewage; m _saltfor only consider that Slagging risk obtains with Na ₂o+0.5K ₂o be composition spray into alkali metal salt maximum level in saline sewage; C _cl=1/N _cl, wherein N _clrepresent the ratio of Cl element and alkali metal salt in saline sewage; m _coalrepresent steam coal consumption; A _arrepresent pit ash content; W represents alkali metal salt mass fraction in Coal Chemical Industry saline sewage.

$m_{\mathrm{salt}}=\frac{m_{\mathrm{coal}}{A}_{\mathrm{ar}}(s_{\mathrm{lim\; it}}-s)}{100(100-s_{\mathrm{lim\; it}})}$ ③

Sodium salt equivalent S=Na in ash ₂o+0.5K ₂o (%); The computational methods of sodium salt limit fixed value in coal:

R＝(A-BV _daf)(Na ₂O+CK ₂O)<R _limt④

Coal ash sodium salt limiting value is S _limit=R _limit/ (A-BV _daf) (%); m _coalfor boiler coal consumption; R is sodium salt limit fixed value in coal; R _limitfor the limiting value of sodium salt limit fixed value in coal, when R is higher than R _limittime, think that sodium salt exceedes maximum crystallized ability in coal, will there is dust stratification contamination problems in this coal ash in boiler operatiopn.

Constant A, B weigh coal affects size model parameter on sodium salt fixed pole limit value; C weighs K ₂the equivalent constant that O affects sodium salt fixed pole limit value; V _daffor dry ash free basis volatile matter content; Na ₂o and K ₂o represents the mass fraction that this two oxides is shared in coal ash respectively.

A kind of method based on stove combustion process Coal Chemical Industry saline sewage provided by the invention, has practical, good economy performance, has good theoretical foundation, and method is simple, the features such as operating cost is low.Be applicable to the scale process of various concentration Coal Chemical Industry saline sewage.

Claims (3)

1., based on a method for stove combustion process Coal Chemical Industry saline sewage, it is characterized in that:

1) by saline sewage by concentrator (1) process, form the saline sewage that salt concentration is at least 5%, the saline sewage after concentrated sprayed into burner hearth and carries out mixing burning;

2) the maximum straying quatity of saline sewage of variable concentrations is calculated:

Q＝M _salt/w①

In formula:

M _salt＝min(C _sm _salt,0.003m _coalC _cl,0.0148A _arm _coal)②

Wherein, Q is the maximum straying quatity of Coal Chemical Industry saline sewage; M _saltfor considering the limit content spraying into alkali metal salt in saline sewage that contamination, chlorine corrosion and experimental data obtain; C _s=(N ₁/ N ₂+ 0.5N ₃/ N ₄), N ₁for Na ₂the mass fraction of Na element in O, N ₂represent the Na element mass fraction in sodium salt in saline sewage, N ₃for K ₂the mass fraction of K element in O, N ₄represent the mass fraction of K element in sylvite in saline sewage; m _saltfor only consider that Slagging risk obtains with Na ₂o+0.5K ₂o be composition spray into alkali metal salt maximum level in saline sewage; C _cl=1/N _cl, wherein N _clrepresent the ratio of Cl element and alkali metal salt in saline sewage; m _coalrepresent steam coal consumption; A _arrepresent pit ash content; W represents alkali metal salt mass fraction in Coal Chemical Industry saline sewage.

2. according to one according to claim 1 based on stove combustion process Coal Chemical Industry saline sewage method, it is characterized in that:

$m_{salt}=\frac{m_{coal}{A}_{ar}(s_{\lim it}-s)}{100(100-s_{\lim it})}$ ③

Sodium salt equivalent S=Na in ash ₂o+0.5K ₂o (%); The computational methods of sodium salt limit fixed value in coal:

R＝(A-BV _daf)(Na ₂O+CK ₂O)<R _limt④

Coal ash sodium salt limiting value is S _limit=R _limit/ (A-BV _daf) (%); m _coalfor boiler coal consumption; R is sodium salt limit fixed value in coal; R _limitfor the limiting value of sodium salt limit fixed value in coal;

Constant A, B weigh coal affects size model parameter on sodium salt fixed pole limit value; C weighs K ₂the equivalent constant that O affects sodium salt fixed pole limit value; V _daffor dry ash free basis volatile matter content; Na ₂o and K ₂o represents the mass fraction that this two oxides is shared in coal ash respectively.

3. according to one according to claim 1 based on stove combustion process Coal Chemical Industry saline sewage processing method, it is characterized in that: the mode that the saline sewage after concentrated sprays into burner hearth is: to CFBB, from furnace roof or Secondary Air At The Height, concentrated saline sewage is sprayed into burner hearth; To pulverized-coal fired boiler, below secondary air bellow top or burnt wind, concentrated saline sewage is sprayed into burner hearth.