Pyrite acid-making roasting self-control method

Abstract

A pyrite acid-making roasting self-control method comprises a feeding machine used for feeding materials to a roasting furnace, the roasting furnace and a furnace front fan used for adjusting the temperature in the roasting furnace, and the roasting furnace oxygen-sulfur ratio control method comprises the following steps that (a) stability is manually controlled through the feeding machine of the roasting furnace; (b) the ore feeding amount is controlled by adjusting the frequency of a feeder, the oxygen-sulfur ratio of flue gas is maintained to be stabilized at a set value, meanwhile, the oxygen surface value is kept stable, and the invention relates to the field of control systems, in particular to a pyrite acid-making roasting automatic control method. The technology of the patent has industrial initiative, and the problem of automatic control of the pyrite acid-making roasting furnace in the sulfuric acid industry is solved. By adopting the technology of the patent, the automatic control rate of the roasting furnace is 100%, the operation frequency is 0, the labor and equipment maintenance cost can be reduced, and the economic value of the sulfuric-acid slag is improved.

Description

Technical Field

[0001] The present invention relates to the field of control systems, and in particular to an automatic control method for roasting pyrite acid. Background Art

[0002] Sulfuric acid is a key industrial chemical used in a wide range of applications, including the manufacture of fertilizers, non-alkaline detergents, skin care products, paint additives, and explosives. In the metallurgical industry, most smelting raw materials are metal sulfides, such as zinc sulfide and copper sulfide. Smelting produces large amounts of sulfur dioxide flue gas, which seriously pollutes the environment. However, when the SO2 concentration in the flue gas reaches a certain level, the flue gas can be converted into sulfuric acid by using it for waste treatment. This not only produces sulfuric acid, but also achieves the goals of pollutant reduction and comprehensive waste gas utilization. In my country, the majority of non-ferrous metal smelting flue gas contains low-concentration sulfur dioxide. However, with the development of oxygen-enriched smelting technology, a number of high-concentration SO2 acid-producing enterprises have emerged.

[0003] Currently, in the acid production process, acid production factors are mainly controlled by instruments and human cognitive operations, which is inefficient. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for automatically controlling the roasting of pyrite acid in order to overcome the above-mentioned shortcomings.

[0005] The method for controlling the oxygen-sulfur ratio of a roasting furnace according to the present invention is as follows: (a) manually controlling and stabilizing the roasting furnace feeder; (b) By adjusting the feeder frequency to control the amount of ore fed, the flue gas oxygen-sulfur ratio is maintained at the set value while the oxygen meter value is kept stable. The control model is as follows: , , Among them, the oxygen level is controlled at 1-3%.

[0006] The roasting furnace is equipped with dual oxygen meters, one for use and one for backup, which can be selected for automatic control. When the automatic oxygen meter fails, the control can be switched to the backup oxygen meter to increase the reliability of the automatic control.

[0007] The furnace temperature control model is as follows:

[0008] in, T(t) real-time temperature of furnace bottom; f(t) fan frequency (control input); Q(t) combustion-supporting air volume at the furnace bottom; Kf fan frequency-air volume ratio coefficient; α Combustion efficiency coefficient (air volume-heat conversion) C Furnace heat capacity h heat loss coefficient The control strategy is as follows:

[0009] A dual-thermometer control scheme for the roasting furnace is adopted. The two thermometers are one for use and one for backup. They can be selected during automatic control. When the automatic temperature meter fails, the control can be switched to the other thermometer to increase the reliability of the automatic control.

[0010] The DCS control system and PID controller are used to set the optimal PID parameters according to the roasting furnace process parameters to achieve the purpose of control stability.

[0011] The fan motor in front of the furnace adopts a high-voltage frequency converter. According to the roasting furnace process, the frequency converter frequency is adjusted to adjust the fan speed and air volume, so as to achieve the purpose of stably adjusting the air volume of the roasting furnace.

[0012] The advantages of this invention are: This patented technology is an industry first, solving the problem of automatic control of pyrite acid roasters in the sulfuric acid industry. Using this patented technology, the roaster has a 100% automatic control rate and zero operation frequency, which can reduce labor and equipment maintenance costs and increase the economic value of sulfuric acid slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention.

[0014] Figure 2 This is the furnace temperature automatic control trend chart; Figure 3 Graph oxygen meter automatic control trend graph; Figure 4 Figure 2. Furnace temperature and oxygen meter automatic control trend chart. DETAILED DESCRIPTION

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0017] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0018] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "inner," "outer," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. These terms are only used to facilitate the description of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limitations on the present invention. In addition, if the terms "first," "second," etc. appear in the description of the present invention, they are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0020] As shown in the figure, the present invention provides an automatic control method for pyrite acid roasting, comprising a feeder for feeding the roaster, the roaster, and a furnace front blower for regulating the temperature in the roaster. The method is characterized in that the oxygen-sulfur ratio control method of the roaster is as follows: 1) manual control of the roaster feeder is stable; (b) By adjusting the feeder frequency to control the amount of ore fed, the flue gas oxygen-sulfur ratio is maintained at the set value while the oxygen meter value is kept stable. The control model is as follows:

[0021]

[0022] Among them, the oxygen level is controlled at 1-3%.

[0023] The roasting furnace is equipped with dual oxygen meters, one for use and one for backup, which can be selected for automatic control. When the automatic oxygen meter fails, the control can be switched to the backup oxygen meter to increase the reliability of automatic control.

[0024] Example of adjusting the feeder frequency to control the amount of ore fed:

[0025]

[0026]

[0027]

[0028] A dual-thermometer control scheme for the roasting furnace is adopted. The two thermometers are one for use and one for backup. They can be selected during automatic control. When the automatic temperature meter fails, the control can be switched to the other thermometer to increase the reliability of the automatic control.

[0029] The DCS control system and PID controller are used to set the optimal PID parameters according to the roasting furnace process parameters to achieve the purpose of control stability.

[0030] The fan motor in front of the furnace adopts a high-voltage frequency converter. According to the roasting furnace process, the frequency converter frequency is adjusted to adjust the fan speed and air volume, so as to achieve the purpose of stably adjusting the air volume of the roasting furnace.

[0031] The furnace temperature control model is as follows:

[0032] in,

[0033] The control strategy is as follows:

[0034] Example of adjusting the frequency of the inverter: Due to a brief fluctuation in air volume (from 800 m³ / h to 750 m³ / h), the oxygen supply was reduced, resulting in incomplete sulfur combustion and a sudden drop in the oxygen meter value to 2.3%.

[0035]

[0036]

[0037] Verification results:

[0038]

[0039]

[0040]

[0041] Taking the 300,000 tons / year pyrite acid plant as an example, the manual operation frequency of the roaster was reduced from 300 times to 0 times, and the roaster temperature and oxygen meter indicators were stable. Figure 2 、 Figure 3 ,The upper fluctuation curve is before automatic control, and the lower fluctuation curve is after automatic control.

Claims

1. A pyrite acid roasting automatic control method, comprising a feeder for feeding material to a roasting furnace, a roasting furnace, and a furnace front blower for regulating the temperature in the roasting furnace, characterized in that: The method for controlling the oxygen-sulfur ratio of the roaster is as follows: (a) manually controlling the roaster feeder to stabilize; (b) By adjusting the feeder frequency to control the amount of ore fed, the flue gas oxygen-sulfur ratio is maintained at the set value while the oxygen meter value is kept stable. The control model is as follows: ， 。 2. The automatic control method of a pyrite acid roasting furnace according to claim 1, characterized in that: The oxygen level is controlled at 1-3%.

3. The automatic control method of a pyrite acid roasting furnace according to claim 1, characterized in that The roasting furnace is equipped with dual oxygen meters, one for use and one for backup, which can be selected for automatic control. When the automatic oxygen meter fails, the control can be switched to the backup oxygen meter to increase the reliability of the automatic control.

4. The automatic control method of a pyrite acid roasting furnace according to claim 1, characterized in that The furnace temperature control model is as follows: ， in, T(t) real-time temperature of furnace bottom; f(t) fan frequency (control input); Q(t) combustion-supporting air volume at the furnace bottom; Kf fan frequency-air volume ratio coefficient; α Combustion efficiency coefficient (air volume-heat conversion); C is the heat capacity of the furnace; h heat loss coefficient; The control strategy is as follows: 。 5. The automatic control method of a pyrite acid roasting furnace according to claim 4, characterized in that A dual-thermometer control scheme for the roasting furnace is adopted. The two thermometers are one for use and one for backup. They can be selected during automatic control. When the automatic temperature meter fails, the control can be switched to the other thermometer to increase the reliability of the automatic control.

6. The automatic control method of a pyrite acid roasting furnace according to claim 1, characterized in that The DCS control system and PID controller are used to set the optimal PID parameters according to the roasting furnace process parameters to achieve the purpose of control stability.

7. The automatic control method of a pyrite acid roasting furnace according to claim 4, characterized in that The fan motor in front of the furnace adopts a high-voltage frequency converter. According to the roasting furnace process, the frequency converter frequency is adjusted to adjust the fan speed and air volume, so as to achieve the purpose of stably adjusting the air volume of the roasting furnace.

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