RU2264361C2 - Method of lime production - Google Patents

Abstract

FIELD: chemical industry; metallurgy industry; construction materials industry; methods of a lime burning in the shaft charge furnaces.

SUBSTANCE: the invention is pertaining to the method of a lime burning in the shaft charge furnaces and may be used at the chemical, metallurgical enterprises and the enterprises producing construction materials. The technical result is a raise of a degree of burning of limestone up to 83-93 % at a high heat efficiency - no less than 80 % - and extension of the range of usage of the solid fuel. In the method of lime production by a limestone burning at incineration of the solid fuel consisting of coke and-or a mixture of coke and a carbon-bearing material the mass ratio of the limestone and carbon in the solid fuel makes 1:(0.050-0.075), and the ratio of the medium-sized lumps of the solid fuel and limestone is 1:(1-2). The average dimension of the lumps of the solid fuel makes 25-100 mm, and the average dimension of the lumps of limestone makes 30-180 mm. As coke they use the metallurgical coke and-or the coke coal-mining coke, and-or the foundry coke, and-or the foundry coal-mining coke, and-or the oil coke, and-or the coke blast-furnace coke and-or in the capacity of carbon-bearing material they use bituminous coal and-or hard coal.

EFFECT: the invention ensures a raise of a degree of burning of limestone up to 83-93 % at a high heat efficiency - no less than 80 % - and extension of the range of usage of the solid fuel.

3 cl, 1 ex, 1 tbl

Description

The invention relates to methods for producing lime in shaft fill furnaces and can be used in chemical, metallurgical enterprises and enterprises producing building materials.

A known method of producing lime by burning carbonate-containing raw materials by burning solid fuel, consisting of a mixture of blast furnace coke and a carbon-containing material containing 4-20 wt.% Oxides, 3-12 wt.% Volatile components, with a mass ratio of (CaO + MgO) / ( SiO ₂ + Al ₂ O ₃ ) - 0.66-0.2. Coal and anthracite are used as the carbon-containing material, the ratio of blast furnace coke to the carbon-containing material is 1: 0.1-0.2: 0.8. In addition, during firing, the content of CO _{2 is} maintained in the range of 38-40 vol.% [1].

The disadvantage of this method is the low degree of calcination of carbonate raw materials, as well as a limited range of ratios of blast furnace coke and carbon-containing material due to stringent requirements for the chemical composition of the latter and the difficulty of maintaining the content of CO ₂ in the range of 38-40 vol.%.

Closest to the proposed invention is a method for producing lime by calcining limestone in a shaft furnace when burning solid fuel, a mixture of blast furnace and petroleum coke in a ratio of 1: (0.3-1) is used as solid fuel [2].

The disadvantages of this method are the low degree of calcination of limestone at high thermal efficiency of the furnace and a significant decrease in thermal efficiency at an increased degree of calcination, as well as the limited range of solid fuel used. All this is due to the fact that the known method does not take into account the influence of the ratio of limestone and carbon in solid fuel and the ratio of the average sizes of pieces of limestone and solid fuel. In addition, in the known method, the range of solid fuel used is limited to blast furnace and petroleum coke.

The task of the invention is to eliminate the above disadvantages of the known method, namely: increasing the degree of calcination of lime at high thermal efficiency and expanding the range of solid fuel used.

The problem is achieved due to the proposed method for producing lime, which includes calcining limestone during the combustion of solid fuels, consisting of coke and / or a mixture of coke and carbon-containing material, with a mass ratio of limestone and carbon in solid fuel 1: (0,050-0,075) and the ratio of the average sizes of pieces solid fuels and limestone 1: (1-2). In addition, limestone with an average piece size of 30-180 mm and solid fuel with an average piece size of 25-100 mm are used. Metallic coke and / or coke coal and / or coke foundry and / or coke foundry coal and / or coke petroleum and / or coke blast furnace and / or anthracite and / or coal are used as solid fuel.

The essence of the proposed method is as follows. A mixture of limestone and solid fuel is prepared, consisting of coke and / or a mixture of coke and a carbon-containing material, and metallurgical coke according to TU 1104-076100-0019437-159-96 and / or coal coke according to TU 14-7-49 is used as coke. -80 and / or coke foundry coke in accordance with GOST 3340-88 and / or delayed coking petroleum coke in accordance with TU 0258-103-008636, coal is used as carbon-containing material, for example, TPKO, TPK and / or anthracite grade GOST 25543-88 grade A.

When preparing the mixture observe the mass ratio of limestone and carbon in solid fuel 1: (0,050-0,075). The average size of the pieces of limestone is maintained in the range of 30-180 mm, and the average size of the pieces of solid fuel is 25-100 mm. Moreover, the ratio of the average size of solid fuel and limestone is maintained in the range of 1: (1-2). The prepared mixture is loaded into a bulk kiln and limestone is calcined by known methods. The effectiveness of the firing process is judged by the degree of firing, which indicates the percentage of limestone converted to lime (calcium oxide), and the thermal efficiency, which shows what percentage of the heat released during the combustion of solid fuels went into the decomposition of limestone.

The implementation of the process of producing lime by the proposed method allows to increase the degree of calcination of lime at high thermal efficiency and to expand the range of solid fuel used.

It should be emphasized that a prerequisite for a positive effect is strict adherence to the specified mass ratio of limestone and carbon in solid fuel 1: (0.050-0.075) and the ratio of the average sizes of pieces of solid fuel and limestone in the range 1: (1-2). Failure to comply with at least one of these requirements does not allow to achieve a positive effect.

As follows from the results obtained during the testing of the method, the process indicators are significantly improved:

The degree of calcination of lime rises to 83-93%, with a thermal efficiency of at least 80%.

The range of solid fuels used is expanding - it is possible to use metallurgical and / or coke of coal and / or coke of foundry and / or coke of foundry coal and / or coke of oil and / or coke of blast furnace and / or anthracite and / or coal.

Thus, between the new features of the proposed method:

the mass ratio of limestone and carbon in solid fuel 1: (0.050-0.075), the ratio of the average sizes of pieces of solid fuel and limestone 1: (1-2), the average size of pieces of limestone 30-180 mm, the average size of pieces of solid fuel 25-100 mm and the positive effect achieved in this case: increasing the degree of lime calcination at high thermal efficiency and expanding the range of solid fuel used - there is a new causal relationship: the presence of these signs in the totality of the features of the proposed method ensures a positive effect, and the absence of any of these signs does not allow to obtain a positive effect.

The essence of the proposed method and its advantages in comparison with the object of the prototype are given in the examples.

Examples:

The mixture consisting of limestone and solid fuel, consisting of coke and / or a mixture of coke and carbon-containing material, with a mass ratio of limestone and carbon in solid fuel 1: (0,050-0,075), an average size of limestone pieces of 30-180 mm, an average size of pieces solid fuel 25-100 mm and the ratio of the average sizes of the pieces of solid fuel and limestone 1: (1-2), is loaded into a bulk calcareous calcining shaft furnace and firing is carried out by known methods. The composition of the mixture and process indicators are presented in table 1.

Table 1
The composition of the mixture and indicators of the firing process Example No. Solid fuel The ratio of limestone and carbon solid fuel, mass. The ratio of the average sizes of pieces of solid fuel and limestone The average size of pieces of solid fuel, mm The average size of pieces of limestone, mm The degree of firing,% Thermal efficiency (Heat fraction for decomposition of CaCO ₃ ),% Note 1 Blast furnace coke; Petroleum Coke 1: 0.3 1: 0,049 1: 1.71 70 120 74.8 81.9 prototype 2 Blast furnace coke Petroleum coke 1: 0.4 1: 0,076 1: 1,60 75 120 92.9 66.5 prototype 3 Blast furnace coke Oil coke 1: 0.5 1: 0,069 1: 4.3 thirty 130 79.8 62,4 prototype 4 Blast furnace coke Oil coke 1: 0.6 1: 0,068 1: 0.8 fifty 40 90.6 71.7 prototype 5 Blast furnace coke Oil coke 1: 0.7 1: 0,066 1: 1.95 95 185 74.6 60.8 prototype 6 Coke blast furnace Petroleum coke 1: 0,8 1: 0,067 1: 1,60 25 40 79.8 64,4 prototype 7 Coke blast furnace Petroleum coke 1: 0.9 1: 0,073 1: 1.4 110 150 90.2 66.6 prototype 8 Blast furnace coke Oil coke 1: 1,0 1: 0,072 1: 1,2 thirty 35 94.7 70.9 prototype nine Metallurgical coke; Anthracite 1: 1 1: 0,064 1: 1,5 100 150 90.7 80.2 according to the invention 10 Blast furnace coke; Foundry coke 1: 0.1 1: 0,075 1: 2 25 fifty 94.6 80.1 according to the invention eleven Metallurgical coke 1: 0.06 1: 1.8 fifty 90 90.7 81.1 according to the invention 12 Metallurgical coke; Petroleum Coke 1: 0.5 1: 0,064 1: 1.71 70 120 92.1 80.8 according to the invention thirteen Coal coke; Foundry coke 1: 0.3 1: 0.056 1: 1,2 70 120 90,4 88.2 according to the invention 14 Coal foundry coke; Anthracite 1: 0.5 1: 0,059 1: 1.59 110 175 87 87.1 according to the invention fifteen Blast furnace coke 1: 0.058 1: 1.33 thirty 40 91.2 89.2 according to the invention 16 Foundry coke; Coal; Petroleum Coke 1: 0.5: 0.3 1: 0.06 1: 1.67 60 100 93,4 85,4 according to the invention 17 Petroleum coke; Coal 1: 1 1: 0,050 1: 1.43 70 100 91 90.3 according to the invention

The data obtained indicate that when using limestone and solid fuel, consisting of coke and / or a mixture of coke and carbon-containing material, the proposed particle size distribution, the ratio of the average sizes of pieces of solid fuel and limestone, the mass ratio of limestone and carbon in solid fuel, the degree of calcination of limestone increases to 83-93% with a thermal efficiency of at least 80%, while the range of solid fuel used is expanding - it is possible to use metallurgical coke and / or coal coke o and / or coke foundry and / or coke foundry coal and / or coke petroleum and / or coke blast furnace and / or anthracite and / or coal.

Sources of information

1. RF patent RU 2186042 C2, class. IPC 7 C 04 V 2/10 BI No. 212002.

2. USSR copyright certificate 1162764, cl. S 04 B 2/02, 1985

Claims (3)

1. The method of producing lime by calcining limestone during the combustion of solid fuels, consisting of coke and / or a mixture of coke and carbon-containing material, characterized in that the mass ratio of limestone and carbon in solid fuel is 1: (0,050 ÷ 0,075), and the ratio of the average size pieces of solid fuel and limestone 1: (1 ÷ 2). 2. The method according to claim 1, characterized in that the average size of the pieces of solid fuel is 25-100 mm, and the average size of the pieces of limestone is 30-180 mm. 3. The method according to claim 1 or 2, characterized in that metallurgical coke and / or coal coke and / or foundry coke and / or coal foundry coke and / or petroleum coke and / or coke are used as coke blast furnace and / or as carbon-containing material use coal and / or anthracite.