CN112940790B

CN112940790B - Method for quickly and efficiently regulating and controlling flow temperature of coal ash

Info

Publication number: CN112940790B
Application number: CN202110261003.0A
Authority: CN
Inventors: 马晓迅; 谢良才; 白柏杨; 穆航; 吕园; 张穗穗; 强路遥; 徐龙; 孙鸣
Original assignee: Northwest University
Current assignee: Northwest University
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2022-06-24
Anticipated expiration: 2041-03-10
Also published as: CN112940790A

Abstract

A method for quickly and efficiently regulating and controlling the flowing temperature of coal ash comprises the steps of carrying out ashing treatment on a coal sample, and analyzing the chemical composition of the coal ash; when the coal ash is acidic ash with A/B more than or equal to 6.72, the coal ash is adjusted to be neutral ash by adding alkaline substances; wherein A represents SiO₂、Al₂O₃With TiO₂B represents CaO, Fe₂O₃、MgO、K₂O and Na₂The total mass of O; when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) Regulating and controlling coal ash FT; when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+m_MgO) The coal ash FT is regulated and controlled by the A. The method provided by the invention not only realizes the target of fast and efficient regulation and control of the coal ash FT, but also can be carried out in various ways such as coal blending, additive addition, coal blending and additive combined addition and the like in the regulation and control process.

Description

Method for quickly and efficiently regulating and controlling flow temperature of coal ash

Technical Field

The invention belongs to the field of coal gasification, and particularly relates to a method for quickly and efficiently regulating and controlling coal ash FT.

Background

Coal gasification is an important way for efficient and clean utilization of coal resources and is also the basis for development of the coal chemical industry. At present, the entrained flow gasification technology has become a major development direction due to its advantages of high conversion rate, large production capacity, etc. However, at the same time, the entrained flow gasification time is generally in the order of "seconds" due to the restriction of the operating space of the gasification chamber, and therefore, the strength of the entrained flow gasification is several times or even several tens times higher than that of the fixed bed gasification and the fluidized bed gasification. In order to effectively make up for the defect of insufficient gasification reaction caused by short coal particle gasification residence time, the entrained flow gasification technology adopts fine coal powder (generally the particle size is less than 100 μm to increase the contact area of the gasification reaction) and higher gasification reaction temperature (generally 1300-1500 ℃ to increase the reaction rate). Under the conditions of entrained flow pulverized coal and high-temperature second-level gasification, the influence of the organic matter gasification reactivity of different coal types on entrained flow gasification is almost the same, and the influence of inorganic mineral substances (coal ash) in coal on entrained flow gasification is more obvious. The reason why the coal ash has a remarkable influence on the gasification of the entrained flow bed is that the operating temperature of the entrained flow bed gasification furnace is high, and the ash needs to be discharged in a liquid state slag discharging manner. At present, the entrained flow gasifier such as a GE, a GSP and a Shell at foreign countries, an aerospace furnace, a multi-component slurry, an opposed multi-nozzle and the like at home are all carried out in a liquid state slag discharging mode in large-scale industrial production. Nowadays, the melting characteristics of coal ash are regarded as an important index of coal for entrained flow gasification.

Numerous studies have shown that: the melting characteristics of coal ash are closely related to the ash components, and the chemical composition of the ash mainly comprises SiO₂、Al₂O₃、CaO、Fe₂O₃、MgO、Na₂O、K₂O、TiO₂And the like. At high temperature, a series of complex physical and chemical reactions occur among the chemical components in the coal ash, and complex crystalline and glassy amorphous substances are formed, so that the coal ash does not have a fixed melting point temperature but a melting temperature range. The melting characteristics (AFT) of coal ash are generally expressed in terms of four temperature points, namely the Deformation Temperature (DT), the Softening Temperature (ST), the Hemispherical Temperature (HT), and the Flow Temperature (FT), with FT being the primary reference index in entrained flow gasification. In the actual production of the entrained flow gasifier, the ash liquid slag can be dragged in the air flow and gravityUnder the combined action of the two components, the molten liquid enters the chilling chamber. In the process, if the operation temperature is far higher than the coal ash FT, the fluidity of ash slag is enhanced, so that the scouring and erosion of the refractory lining material are initiated, and the service life of the gasification furnace is finally shortened; meanwhile, if the operation temperature is close to or lower than the coal ash FT, the viscosity of the ash molten slurry is increased, and then slagging and even blockage in the gasifier are caused, and finally the gasifier is stopped. For this reason, researchers have conducted extensive research on FT based on the chemical composition of the coal ash. In the early days, researchers have mainly used regression analysis of data to establish a predictive relationship between soot composition and FT. However, due to the complex composition of coal ash and the large content difference of each component, the coal ash FT and the ash component generally show a nonlinear relationship and the relationship is difficult to be effectively expressed by a mathematical formula. In addition, different occurrence forms and different crystalline state evolution behaviors at high temperature exist in different coal samples of the coal ash, the difficulty of coal ash FT prediction is further increased, and therefore the limitations that prediction accuracy is poor and adaptability is not strong exist in an empirical relational expression obtained by data regression in actual use are caused. In recent years, in order to predict FT of coal ash composition more accurately, students try to establish a prediction relation between the coal ash composition and FT by an intelligent algorithm represented by an artificial neural network, but the traditional artificial neural network has the defects of black box operation, poor result interpretability, incapability of carrying out accurate mathematical description and the like, so that the actual regulation and control effect is not ideal. Therefore, how to predict FT quickly and efficiently has very important practical significance for safe and stable operation of the entrained flow bed gasification slag tapping process.

Disclosure of Invention

In order to effectively overcome the problems in the prior art, the invention provides a method for quickly and efficiently regulating and controlling the FT of the coal ash, which not only has the advantage of simple and convenient method, but also can directly and accurately regulate and control (such as coal blending type and proportion, additive addition type and proportion and the like) according to the requirements of different gasification furnaces.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for quickly and efficiently regulating and controlling the flowing temperature of coal ash comprises the steps of carrying out ashing treatment on a coal sample, and analyzing the chemical composition of the coal ash; when the coal ash is acid ash with A/B more than or equal to 6.72, the coal ash is adjusted to be neutral ash by adding alkaline substances; wherein A represents SiO₂、Al₂O₃With TiO₂B represents CaO, Fe₂O₃、MgO、K₂O and Na₂The total mass of O;

when the coal ash is more than or equal to 0.96 and A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) Regulating and controlling coal ash FT;

when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+m_MgO) The coal ash FT is regulated and controlled by the A.

The invention further improves the following steps: the alkaline substance is Fe₂O₃、CaO、MgO、K₂O and Na₂One or more of O is either a carbonate.

The invention further improves the following steps: the carbonate being Fe₂(CO₃)₃、CaCO₃、MgCO₃、K₂CO₃With Na₂CO₃One or more of (a).

The invention further improves the following steps: when the coal ash is more than or equal to 0.96A/B<Neutral ash of 6.72, FT ═ 136 (m)_Al2O3+TiO2)/B+1143.9。

The invention further improves the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) The concrete process of regulating and controlling the coal ash FT comprises the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash to coal Ash, Al₂O₃With TiO₂One or two of them.

The invention further improves the following steps: when the coal ash is more than or equal to 0.96 and A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) The concrete process of regulating and controlling the coal ash FT comprises the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 adding CaO and Fe under the premise of neutral ash₂O₃、MgO、K₂O and Na₂And one or more of O.

The invention further improves the following steps: when the coal ash is A/B<0.96 basic ash, FT 116.81 ═ m_CaO+MgO)/A+1122.3。

The invention further improves the following steps: when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+MgO) The specific process of regulating and controlling the coal ash FT by the method comprises the following steps: in the coal ash of A/B<On the premise of 0.96 alkaline ash, one or two of CaO and MgO are added into the coal ash.

The invention further improves the following steps: when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+MgO) The specific process of regulating and controlling the coal ash FT by the method comprises the following steps: in the coal ash of A/B<Adding SiO into the coal ash under the premise of 0.96 alkaline ash₂、Al₂O₃With TiO₂One or more of them.

Compared with the existing technology, the invention has the following remarkable beneficial effects:

(1) aiming at the pain point of lack of rapid and efficient regulation and control of the coal ash FT at the present stage, the method effectively realizes the goal of rapid and efficient regulation and control of the coal ash FT by adopting the coal ash classification treatment and combining with the regulation and control of key factors, and highlights the pertinence of the method.

(2) In the operation of quickly and efficiently regulating and controlling the coal ash FT, the method can be carried out by adopting various modes of adjusting the chemical composition of the mixed ash sample, such as coal blending, addition of an auxiliary agent, or combination of coal blending and addition of the auxiliary agent, and the like, so that the operability of the method is obvious.

(3) The method can also be directly carried out by adjusting the chemical composition of the ash sample according to the FT parameters actually required by the gasifier, which shows that the method has better applicability.

Furthermore, the method provided by the invention has the characteristics of simplicity and high efficiency, and the used auxiliary agent also has the advantages of wide raw materials and low price.

Drawings

FIG. 1 is a process flow diagram of the present invention for regulating coal ash FT.

FIG. 2 is a graph of the effect of coal ash A/B on coal ash FT.

FIG. 3 shows the equation when 0.96 ≦ A/B<At 6.72 hours, (m)_Al2O3+m_TiO2) Influence of/B on FT.

FIG. 4 shows the relationship between A and B<At 0.96 hour (m)_Al2O3+m_TiO2) Influence of/A on FT.

Detailed Description

The operation of the present invention will be described in detail with reference to the accompanying drawings.

The Flow Temperature (FT) can be quickly and efficiently regulated by regulating the chemical composition in the coal ash. When the chemical composition of the coal ash is regulated, coal can be blended by adopting one or more kinds of coal according to different mass proportions, or different additives are added, or the coal blending is carried out in a manner of jointly adding the additives.

Referring to fig. 1 and 2, the present invention includes the steps of:

(1) carrying out ashing treatment on a certain coal sample according to GB/T212-2008 national standard, and carrying out chemical composition analysis on ash content by an X-ray fluorescence instrument;

(2) and classifying the coal ash according to the chemical composition analysis result of the ash. The composition of the fly ash is A/B>6.72, the FT of the coal ash is higher than 1400 ℃, which exceeds the normal operation required temperature of the entrained flow gasifier, and the content of alkaline substances in the ash can be adjusted to be more than or equal to 0.96 and less than or equal to A/B by means of coal blending, addition of an auxiliary agent and the like<6.72, and accurately regulating and controlling the neutral ash according to the relation 2. Wherein A represents SiO₂、Al₂O₃With TiO₂Total mass m of_{SiO2+Al2O3+TiO2}B represents CaO or Fe₂O₃、MgO、K₂O and Na₂Total mass m of O_{CaO+Fe2O3+MgO+K2O+Na2O}；

Relation 1: acid ash, A/B ≥ 6.72, FT>1400 ℃, which is not suitable for entrained flow gasification slag tapping operation, and can be adjusted to neutral ash by adding alkaline substances; the alkaline substance is Fe₂O₃、CaO、MgO、K₂O and Na₂One or more of O is either a carbonate. The carbonate being Fe₂(CO₃)₃、CaCO₃、MgCO₃、K₂CO₃With Na₂CO₃One or more of (a).

Relation 2: neutral ash, 0.96 ≦ A/B<6.72 by regulation (m)_Al2O3+m_TiO2) Regulating and controlling coal ash FT; specifically, FT ═ 136 ═ m (m)_Al2O3+m_TiO2) B + 1143.9; wherein m is_Al2O3Represents Al₂O₃Mass of (c), m_TiO2Represents TiO₂The quality of (c). When the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash to which Al is added₂O₃With TiO₂One or two of them, or adding CaO and Fe₂O₃、MgO、K₂O and Na₂And one or more of O.

(3) The composition of coal ash is 0.96 ≦ A/B<6.72 neutral Ash (m) in the Ash can be changed by blending coal or adding an auxiliary agent according to the relation 2_Al2O3+m_TiO2) The ratio of/B, adjusted to the target temperature, is shown in detail in FIG. 3.

(4) The composition of the fly ash is A/B<0.96 basic ash, the ash content (m) can be changed according to the relation 3 by means of coal blending or addition of an auxiliary agent_CaO+MgO) The ratio of/A, adjusted to the target temperature, is shown in detail in FIG. 4. Wherein m is_CaOMass of expression, m_MgORepresents the mass of MgO.

Relation 3: alkaline ash A/B<0.96 by regulation (m)_CaO+m_MgO) The coal ash FT is regulated and controlled by the A. By regulating (m)_CaO+MgO) The specific process of regulating and controlling the coal ash FT by the method comprises the following steps: in the coal ash of A/B<On the premise of 0.96 alkaline ash, one or two of CaO and MgO are added into the coal ash. Or when the coal ash is A/B<Adding SiO into the coal ash under the premise of 0.96 alkaline ash₂、Al₂O₃With TiO₂One or more of them.

Specifically, FT ═ 116.81 (m)_CaO+MgO)/A+1122.3

The present invention will be described in detail with reference to the following examples.

Example 1

(1) And (3) selecting the Jincheng anthracite (JC) and the corn straw (YM) with obvious ash content composition difference for explanation. First, JC and YM are subjected to ashing treatment, and the chemical compositions of the respective ash samples are analyzed.

(2) The A/B of the ash sample was calculated from the results of the analysis of the chemical composition of the ash and the results are detailed in Table 1.

TABLE 1 analysis of chemical composition of JC grey and YM grey

Item	SiO₂	A1₂O₃	Fe₂O₃	CaO	MgO	TiO₂	K₂O	Na₂O	A/B
										JC	47.00	33.55	7.99	5.16	1.60	0.85	0.38	0.46	5.22
XY	53.37	2.94	1.46	7.17	4.06	0.16	19.61	0.86	1.70

(3) From table 1, it can be seen that both ashes belong to neutral ash samples, and FT can be regulated by using the key factor 1. FT of JC gray and YM gray calculated by relational expression 2 and the measured results are shown in table 2. The accuracy of the calculation results is high as can be seen from table 2.

TABLE 2 FT analysis of JC gray versus YM gray

(4) As can be seen from Table 2, the FT of JC ash is higher than 1400 ℃ and cannot be directly applied to entrained flow gasification, so that the FT of JC ash needs to be regulated and controlled, YM is taken as a raw material and is treated by means of coal blending, and the regulated and controlled target temperatures are respectively 1350 ℃ and 1300 ℃. Based on the set target temperature and the guidance of relation 2, it was calculated that YM with an added mass ratio of about 40% could achieve the target of 1350 ℃ and YM with an added mass ratio of about 60% could achieve the target of 1300 ℃. The results of the coal blending control are shown in table 3. As can be seen from Table 3, the accuracy of the regulation and control of the present invention is much higher than the requirement of the reproducibility of the national standard test.

TABLE 3 FT analysis of JC gray versus YM gray

Example 2

(1) Jincheng anthracite (JC) and Shenhua liquefaction residue (DCLR) with obvious ash component difference are selected for explanation. First, JC and DCLR were subjected to ashing treatment, and the chemical compositions of the respective ash samples were analyzed.

(2) The A/B of the ash sample was calculated from the results of the analysis of the chemical composition of the ash and the results are detailed in Table 4.

TABLE 4 chemical composition analysis of JC Gray and DCLR Gray

Item	SiO₂	A1₂O₃	Fe₂O₃	CaO	MgO	TiO₂	K₂O	Na₂O	A/B
										JC	47.00	33.55	7.99	5.16	1.60	0.85	0.38	0.46	5.22
XY	21.3	9.37	25.74	15.23	0.95	2.05	0.20	1.58	0.75

(5) As can be seen from table 4, JC ash belongs to a neutral ash sample, and DCLR ash belongs to a basic ash sample, and therefore FT was calculated using relational expressions 2 and 1, respectively. The calculated JC gray to DCLR gray FTs and observed results are shown in table 5. It can be seen from table 5 that the calculation results are highly accurate.

TABLE 5 FT analysis of JC gray versus DCLR gray

(6) As can be seen from table 5, the FT of JC ash is higher than 1400 ℃ and cannot be directly applied to entrained flow gasification, so it needs to be regulated and controlled, DCLR is used as a raw material and treated by coal blending, and the target temperature of regulation and control is 1350 ℃ and 1250 ℃ respectively. According to the set target temperature and the guidance of the relational expression 2, it is found that the DCLR at an added mass ratio of about 20% can achieve the target of 1350 ℃, and the DCLR at an added mass ratio of about 60% can achieve the target of 1250 ℃. The results of coal blending control are shown in table 6. As can be seen from Table 6, the accuracy of the regulation and control of the present invention is much higher than the requirement of the reproducibility of the national standard test.

TABLE 6 FT analysis of JC Gray vs. DCLR Gray

According to the invention, the coal is subjected to ashing treatment, the chemical composition of the discharged ash is analyzed, and the discharged ash is divided into acid ash, neutral ash and alkaline ash according to the characteristics of the chemical composition. For acid ash, the FT is higher than 1400 ℃, which is not suitable for gasification operation of an entrained flow bed, and the acid ash can be converted into neutral ash by adding coal blending, alkaline auxiliary agents and the like, and then accurately regulated and controlled. For neutral ash, its FT can be precisely regulated by key factor 1. For alkaline ashes, the FT can be precisely regulated to the target temperature by key factor 2. The method provided by the invention not only realizes the aim of quickly and efficiently regulating and controlling the coal ash FT, but also can be carried out in various ways such as coal blending, additive adding, coal blending and additive combined adding and the like in the regulating and controlling process. In addition, the auxiliary agents used in the invention have the characteristics of wide distribution and low cost.

Compared with the patent CN 106675657A, the invention has the following advantages:

(1) patent CN 106675657 a discloses a method for regulating and controlling the flow temperature of high melting point coal ash. The main contents are as follows: lead to FT for more acidic components>Coal at 1400 deg.C by blending or adding CaO, MgO, Fe₂O₃One or more of CaO, MgO and Fe are added or added₂O₃The at least one salt reduces the amount of acidic components in the ash to reduce the coal ash FT. But it is directed only to acidsThe high-melting-point coal ash with high content of the chemical components is applicable and has poor universality.

(2) A method of regulating the flow temperature of high melting point coal ash is disclosed in patent CN 106675657 a, but it is not described for ash samples with a/B <1.0, making this patent unsuitable for regulation of this type of ash sample FT.

The invention not only has good regulation and control capability for the high-melting-point coal ash with high content of acidic components, but also has excellent regulation and control capability for ash samples with A/B < 1.0; in addition, the invention adopts a regulation and control mode that the classification of the coal ash is combined and key factors can be flexibly regulated, provides a quick and efficient method for regulating and controlling the FT of the coal ash, and embodies the novelty and universality of the invention.

Claims

1. A method for quickly and efficiently regulating and controlling the flowing temperature of coal ash is characterized by comprising the following steps: carrying out ashing treatment on the coal sample, and analyzing the chemical composition of the coal ash;

when the coal ash is acidic ash with A/B more than or equal to 6.72, the coal ash is adjusted to be neutral ash by adding alkaline substances; wherein A represents SiO₂、Al₂O₃With TiO₂B represents CaO, Fe₂O₃、MgO、K₂O and Na₂The total mass of O;

when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) Regulating and controlling coal ash FT;

when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+m_MgO) Regulating and controlling coal ash FT;

when the coal ash is more than or equal to 0.96A/B<Neutral ash of 6.72, FT 136 ═ m (m)_Al2O3+TiO2)/B+1143.9；

When the coal ash is A/B<0.96 basic ash, FT 116.81 ═ m_CaO+MgO)/A+1122.3。

2. The method for quickly and efficiently regulating and controlling the flowing temperature of the coal ash according to claim 1, wherein the method comprises the following steps: the alkaline substance is Fe₂O₃、CaO、MgO、K₂O and Na₂One kind of OOr more than one or carbonate.

3. The method for rapidly and efficiently regulating and controlling the flowing temperature of the coal ash according to claim 2, is characterized in that: the carbonate being Fe₂(CO₃)₃、CaCO₃、MgCO₃、K₂CO₃With Na₂CO₃One or more of (a).

4. The method for quickly and efficiently regulating and controlling the flowing temperature of coal ash according to claim 1, is characterized in that: when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) The concrete process of regulating and controlling the coal ash FT comprises the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash to which Al is added₂O₃With TiO₂One or two of them.

5. The method for quickly and efficiently regulating and controlling the flowing temperature of the coal ash according to claim 1, wherein the method comprises the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 neutral Ash, by Regulation (m)_Al2O3+m_TiO2) The concrete process of regulating and controlling the coal ash FT comprises the following steps: when the coal ash is more than or equal to 0.96A/B<6.72 adding CaO and Fe under the premise of neutral ash₂O₃、MgO、K₂O and Na₂And one or more of O.

6. The method for quickly and efficiently regulating and controlling the flowing temperature of coal ash according to claim 1, is characterized in that: when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+MgO) The specific process of regulating and controlling the coal ash FT by the method comprises the following steps: in the coal ash of A/B<On the premise of 0.96 alkaline ash, one or two of CaO and MgO are added into the coal ash.

7. The method for quickly and efficiently regulating and controlling the flowing temperature of coal ash according to claim 1, is characterized in that: when the coal ash is A/B<0.96 basic ash, by regulation (m)_CaO+MgO)/AThe specific process for regulating and controlling the coal ash FT comprises the following steps: in the coal ash of A/B<0.96 basic ash, SiO is added to the coal ash₂、Al₂O₃With TiO₂One or more of them.