Calorific value control method for adjusting two kinds of coal gas in rotary kiln

Abstract

The invention belongs to the technical field of rotary kilns, and particularly relates to a calorific value control method for adjusting two coal gases of a rotary kiln, which is characterized in that coal gas calorific value detection and kiln tail temperature detection are utilized to edit coke oven gas and converter coal gas control program models, and the control steps comprise: 1) inputting unit consumption value and daily output of a production variety; 2) calculating the calorific value and the corresponding flow of the coal gas required by production; 3) judging whether the converter gas regulating valve is adjusted for the first time or not; 4) adjusting the coking coal gas to reach the corresponding calorific value flow; 5) detecting whether the kiln tail temperature is normal; 6) judging whether the calorific value reaches the standard; and 7) judging whether the control system exits. The method has the beneficial effects that when the coke oven gas and the converter gas are simultaneously combusted and produced in the rotary kiln, the use amount of the coke oven gas and the converter gas can be automatically controlled according to production requirements, and the automation degree is high; on the premise of meeting the calorific value, the coal gas use cost is reduced, the roasted product quality is improved, and the environment-friendly requirement is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of rotary kilns, and particularly relates to a calorific value control method for regulating two kinds of coal gases in a rotary kiln. Background Art

[0002] The production of a lime rotary kiln mainly involves calcining limestone by burning coal gas. Usually, coke oven gas is used, but this method has the disadvantages of high consumption and high cost. Generally, converter gas is introduced, and two kinds of coal gases are used to control the calcination to reduce production costs. In order to make the mixture of the two kinds of coal gases meet both the calorific value requirement and the cost requirement, the current method is to maintain production by manual control. Such a control method not only has a high labor intensity and low efficiency, but also leads to deviations in the quality of the finished product and production costs due to untimely adjustment.

[0003] Chinese Patent Application No. 202321017759.1 discloses a low-calorific value coal gas preheating system for a lime rotary kiln, which includes a heating unit and a combustion unit. The coal gas and air enter the burner of the flue gas furnace through the coal gas pipeline of the flue gas furnace and the combustion-supporting air pipeline respectively. After the coal gas and air enter the interior of the flue gas furnace, they are mixed and burned at the front end of the burner. The flue gas generated by the combustion enters the heat exchanger flue gas box through the flue gas inlet pipeline. After the flue gas and the coal gas exchange heat inside the heat exchanger, the temperature of the flue gas decreases and the temperature of the coal gas increases. This solution improves the combustion effect by changing the corrugated compensator of the gas pipeline, but the effect is limited.

[0004] Chinese Patent Application No. 202011050714.5 discloses an active lime calcination system, which includes a silo, a rotary kiln and a cooling device. The silo is connected to a preheater, the preheater is connected to the tail box of the rotary kiln, the head box of the rotary kiln is connected to a first burner, the air inlet of the first burner is connected to a combustion-supporting air supply device, and a fuel pipe for supplying low-calorific value coal gas is also connected to the first burner; the head box of the rotary kiln is connected to the cooling device through a discharge channel, and the cooling device is also connected to the head box through a secondary air pipe, so that the waste heat gas in the cooling device can flow into the head box; the preheater is also connected to a second burner, the air inlet of the second burner is connected to the head box, and a fuel pipe for supplying low-calorific value coal gas is also connected to the second burner. This solution improves the combustion effect by changing the structure of the secondary air pipe and the head box, but the effect is also limited.

[0005] The Chinese invention patent with the application number 201210089119.1 discloses a process for calcining high-reactivity lime using low-calorific-value blast furnace gas in the field of lime calcination. The process preheats the low-calorific-value blast furnace gas and converter gas and then separately connects them to the low-calorific-value gas burner at the kiln head of the rotary kiln. Then, the low-calorific-value gas burner is used to inject the low-calorific-value blast furnace gas and converter gas into the rotary kiln for calcining high-reactivity lime. Since the process uses the ventilation method of the waste residual calorific value to replace the high-calorific-value coke oven gas with the low-calorific-value blast furnace gas as the fuel for calcining high-reactivity lime in the lime rotary kiln, the proportioning method of the two different calorific-value gases is not mentioned. Summary of the Invention

[0006] The object of the present invention is to provide a calorific value control method for adjusting two kinds of gases in a rotary kiln, overcoming the deficiencies of the prior art, realizing the automatic control of the flow rates of the two kinds of gases when the rotary kiln uses the two kinds of gases for simultaneous combustion production, reducing the gas use cost, increasing the product quality, and meeting the environmental protection requirements.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A calorific value control method for adjusting two kinds of gases in a rotary kiln, using gas calorific value detection and kiln tail temperature detection, editing the control program model of coke oven gas and converter gas, and using the calorific value required for the daily production of the rotary kiln to distribute and control the two kinds of gases. The calorific value of the converter gas is controlled within 18% and kept constant, and the calorific value required for the production in the kiln is kept constant by controlling the flow rate of the coke oven gas. The control steps include: 1) Input the unit consumption value and daily output of the product type; 2) Calculate the calorific value and corresponding flow rate of the gas required for production; 3) Judge whether the converter gas regulating valve is adjusted for the first time; 4) Adjust the coke oven gas to reach the corresponding calorific value flow rate; 5) Detect whether the kiln tail temperature is normal; 6) Judge whether the calorific value meets the standard; 7) Judge whether the control system exits.

[0009] Further, the calculation formulas for the unit consumption value, daily output, and the total calorific value required for the production of the rotary kiln are as follows: S = H * R / 24 * k1, where: S is the total required heat value; H is the gas unit consumption; R is the daily output; k1 is the loss coefficient, and the value ranges from 0.95 to 0.98.

[0010] Further, in the step 2), the calorific values and corresponding flow rates of the coke oven gas and converter gas are calculated respectively, and the formulas are as follows: AJ = Σt 1As / t * 0.0054 * k2;

[0011] where: AJ is the calorific value of the converter gas; As is the instantaneous flow rate of the converter gas; t is the cumulative time of the instantaneous value of the converter gas, generally taking 3 - 7 s; k2 is the calorific value adjustment coefficient of the converter gas (adjusted according to the gas measurement value), and the value ranges from 1.01 to 0.96;

[0012] BJ = Bs * 0.0175 * k2; where BJ is the calorific value of converter gas; Bs is the instantaneous flow rate of converter gas; k3 is the calorific value adjustment coefficient of coke oven gas, with a value range of 1.01 to 0.96.

[0013] Further, in step 3), if it is the first adjustment, first adjust the flow rate of converter gas to the flow rate corresponding to the required calorific value, and the calorific value proportion occupied by converter gas during adjustment does not exceed 18%.

[0014] Further, if the judgment in step 3) is "yes", after adjusting the converter gas, return to execute step 4). If the judgment is "no", directly execute step 4) to adjust the flow rate of coke oven gas to meet the flow rate required by the remaining calorific value.

[0015] Further, in step 5), it is detected whether the temperature at the kiln tail reaches within 3°C of the set value. If "no", return to step 2), recalculate the calorific value based on the calculated consumed calorific value, and sequentially re - execute steps 2) - step 5) until step 5) is "yes".

[0016] Further, during normal production, the control system only determines and adjusts the calorific value of converter gas for the first time, and the rest uses the adjustment of coke oven gas to meet the calorific value fluctuation of the system, achieving a stable effect.

[0017] Further, the flow rate fluctuation after converting the calorific value fluctuation is less than 50 m 3 / h.

[0018] Further, the formula for recalculating the calorific value is: Bl = (S - AJ) / 0.0175 × k4; where: Bl is the calculated value of the calorific value flow rate of coke oven gas; S is the total required heat value; AJ is the calorific value of converter gas; k4 is the loss coefficient, with a value of 1.015.

[0019] Further, if the calorific value in step 6) does not meet the standard, return to execute steps 2) - step 5). The standard - reaching value is: the flow rate deviation after converting the calorific value is less than 50 m 3 / h.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1) When using both coke oven gas and converter gas for combustion production in a rotary kiln, it can realize the automatic control of the usage amounts of the two gases according to production requirements, with a high degree of automation;

[0022] 2) On the premise of meeting the calorific value, it reduces the gas usage cost, improves the quality of roasted products, and meets the environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the control flow chart of the embodiment of the present invention;

[0024] Figure 2 is the schematic diagram of the rotary kiln gas supply pipeline of the embodiment of the present invention;

[0025] Figure 3 is the curve graph of calorific value comparison before and after 24 hours of application of the embodiment of the present invention;

[0026] Figure 4 is the comparison graph of specific energy consumption calorific value in May - July 2023 and 2024 of the embodiment of the present invention.

[0027] In the figure: 1 - rotary kiln; 2 - converter gas regulating valve; 3 - converter gas flow detection device; 4 - converter gas burner; 5 - converter gas gas source; 6 - converter gas pipeline; 7 - coke oven gas regulating valve; 8 - coke oven gas flow detection device; 9 - coke oven gas burner; 10 - coke oven gas pipeline; 11 - coke oven gas gas source; 12 - rotary kiln mixed combustion chamber. Detailed implementation manners

[0028] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0029] In order to more clearly illustrate the specific implementation manners of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the description of the specific implementation manners or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation manners of the present invention. For those of ordinary skill in the art, without creative efforts, other specific embodiments can also be obtained based on these specific embodiments.

[0030] Generally, the components of the embodiments of the present invention described and shown in the specific embodiments here can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention.

[0031] See Figure 1-2, which is the control flow chart of the calorific value control method for the adjustment of two kinds of gases in a rotary kiln according to an embodiment of the present invention. In the embodiment of the present invention, the two kinds of gases (converter gas source 5 and coke oven gas source 11) used in the rotary kiln 1 are respectively supplied by the converter gas pipeline 6 and the coke oven gas pipeline 10. A converter gas regulating valve 2, a converter gas flow detection device 3 and a converter gas burner 4 are respectively arranged on the converter gas pipeline 6 to complete the flow control and detection of the converter gas; a coke oven gas regulating valve 7, a coke oven gas flow detection device 8 and a coke oven gas burner 9 are arranged on the coke oven gas pipeline 10 to complete the flow control and detection of the coke oven gas. The two kinds of gases are mixed and burned in the mixing combustion chamber 12 of the rotary kiln.

[0032] The calorific value control method for the adjustment of two kinds of gases in the rotary kiln of the present invention utilizes the detection of the calorific value of the gas and the detection of the temperature at the tail of the kiln, edits the control program models of the coke oven gas and the converter gas, and uses the calorific value required for the daily production of the rotary kiln to perform distribution control on the two kinds of gases, controls the calorific value of the converter gas within 18% and keeps it constant, and satisfies the constant calorific value required for the production in the kiln by controlling the flow of the coke oven gas. The control steps include:

[0033] 1) Input the unit consumption value and daily output of the product type; the calculation formula for the input unit consumption, daily output and the total calorific value required for the production of the rotary kiln is as follows: S = H * R / 24 * k1; where: S is the total required heat value; H is the gas unit consumption; R is the daily output; k1 is the loss coefficient, and the value range is 0.95 - 0.98;

[0034] 2) Calculate the calorific value and corresponding flow of the gas required for production; calculate the calorific value and corresponding flow of the coke oven gas and the converter gas respectively, and the formulas are as follows: AJ = Σt 1As / t * 0.0054 * k2;

[0035] where: AJ is the calorific value of the converter gas; As is the instantaneous flow of the converter gas; t is the cumulative time of the instantaneous value of the converter gas, and the value range is 3 - 7s; k2 is the calorific value adjustment coefficient of the converter gas (adjusted according to the gas measurement value), and the value range is 1.01 - 0.96;

[0036] BJ = Bs * 0.0175 * k2;

[0037] where: BJ is the calorific value of the converter gas; Bs is the instantaneous flow of the converter gas; k3 is the calorific value adjustment coefficient of the coke oven gas (adjusted according to the gas measurement value), and the value range is 1.01 - 0.96;

[0038] 3) The converter gas regulating valve determines whether it is the first adjustment. If it is the first time, the converter gas flow will be adjusted to the flow corresponding to the required calorific value first. When adjusting, the calorific value proportion occupied by the converter gas does not exceed 18%. If the judgment is "yes", after adjusting the converter gas, return to step 4) again. If the judgment is "no", directly execute step 4) and adjust the coke oven gas flow to meet the flow required by the remaining calorific value;

[0039] 4) Adjust the coke oven gas to reach the corresponding calorific value flow; detect whether the temperature at the kiln tail is normal; detect whether the temperature at the kiln tail reaches within 3°C of the set value. If "no", return to step 2), recalculate the calorific value based on the calculated consumed calorific value, and sequentially execute steps 2)-5) again until step 5) is "yes";

[0040] The formula for recalculating the calorific value is: Bl = (S - AJ) / 0.0175 × k4;

[0041] Where: Bl is the calculated value of the coke oven gas calorific value flow; S is the total required heat value; AJ is the converter gas calorific value; k4 is the loss coefficient, with a value of 1.015.

[0042] 6) Determine whether the calorific value meets the standard; during normal production, the control system of the present invention only determines and adjusts the calorific value of the converter gas for the first time, and the rest uses the adjustment of the coke oven gas to meet the calorific value fluctuation of the system, achieving a stable effect. The calorific value fluctuation value is that the flow fluctuation after calorific value conversion is less than 50m 3 / h; determine whether the calorific value meets the standard, otherwise return to execute steps 2)-5). The standard value is set as: the flow deviation after calorific value conversion is less than 50m 3 / h;

[0043] 7) Determine whether the control system exits. After the calorific value fluctuation reaches stability, the system can exit or return to execute step 1).

[0044] See Figures 3-4 , which is the comparison chart of the calorific value before and after 24 hours of application of the embodiment of the present invention and the comparison chart of the specific consumption calorific value from May to July in 2023 and 2024. It can be seen that the automatic adjustment has a better effect than the manual adjustment, saving about 20% of the calorific value. When the rotary kiln burns both coke oven gas and converter gas simultaneously, it can realize the automatic control of the usage amounts of the two gases according to the production requirements, with a high degree of automation. On the premise of meeting the calorific value, it reduces the gas usage cost, improves the quality of the products roasted in the rotary kiln, meets the environmental protection requirements, and reduces the waste gas emissions caused by incomplete combustion due to the mismatch of the gas supply volume.

[0045] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the calorific value of two kinds of coal gas in a rotary kiln, characterized in that: By using gas calorific value detection and kiln tail temperature detection, the coke oven gas and converter gas control program model is edited, and the calorific value required for daily production of the rotary kiln is used to control the distribution of the two gases, so that the calorific value of the converter gas is controlled within 18% and kept constant. The calorific value required for production in the kiln is met by controlling the coke oven gas flow rate. The control steps include: 1) inputting the unit consumption value and daily output of the production variety; 2) calculating the calorific value of the gas required for production and the corresponding flow rate; 3) judging whether the converter gas regulating valve is adjusted for the first time; 4) adjusting the coking coal gas to reach the corresponding calorific value flow; 5) detecting whether the temperature at the kiln tail is normal; 6) judging whether the calorific value meets the standard; 7) judging whether the control system is exited.

2. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: The calculation formula for the unit consumption value, daily output and the total calorific value required for rotary kiln production is as follows: S=H*R / 24*k1 Among them: S is the total required heat value; H is the unit gas consumption; R is the daily output; k1 is the loss coefficient with a value of 0.95~0.

98.

3. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: In the step 2), the gas calorific value and corresponding flow rate of the coke oven gas and the converter gas are calculated respectively, and the formula is as follows: AJ=Σt 1As / t*0.0054*k2; Where: AJ is the calorific value of converter gas; As is the instantaneous flow rate of converter gas; t is the cumulative time of the instantaneous value of converter gas, which is generally 3-7s; k2 is the calorific value adjustment coefficient of converter gas (adjusted according to the gas measurement value), which is 1.01~0.96; BJ=Bs*0.0175*k2; BJ is the calorific value of converter gas; Bs is the instantaneous flow rate of converter gas; k3 is the calorific value adjustment coefficient of coke oven gas, ranging from 1.01 to 0.

96.

4. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: If the adjustment in step 3) is the first one, the converter gas flow rate is first adjusted to a flow rate corresponding to the required calorific value, and the calorific value proportion of the converter gas during the adjustment does not exceed 18%.

5. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: If the step 3) is judged as "yes", after adjusting the converter gas, return to step 4). If it is judged as "no", directly execute step 4) to adjust the coke oven gas flow rate to meet the flow rate required by the residual calorific value.

6. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: The step 5) detects whether the kiln tail temperature reaches the set value within 3°C deviation. If "no", return to step 2), recalculate the calorific value based on the calculated consumed calorific value, and re-execute steps 2)-5) in sequence until step 5) is "yes".

7. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 1, characterized in that: During normal production, the control system only performs the first determination and adjustment of the calorific value of the converter gas, and the rest is to use the adjustment of the coke oven gas to meet the calorific value fluctuation of the system to achieve a stable effect.

8. The calorific value control method for two-gas regulation of a rotary kiln according to claim 7, characterized in that: The flow fluctuation after conversion of the calorific value fluctuation value is less than 50m 3 / h range.

9. The calorific value control method for regulating two kinds of coal gases in a rotary kiln according to claim 6, characterized in that: The formula for recalculating the calorific value is: Bl = (S-AJ) / 0.0175×k4; Among them: Bl is the calculated value of the calorific value flow of coke oven gas; S is the total required heat value; AJ is the calorific value of converter gas; k4 is the loss coefficient, which is 1.

015.

10. The calorific value control method for two-gas regulation of a rotary kiln according to claim 1, characterized in that: If the calorific value in step 6) does not meet the standard, then return to step 2) to step 5), and the standard value is: the flow deviation after calorific value conversion is less than 50m 3 / h.

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