Single-control balanced water supply method for ascension pipe

Abstract

The invention discloses a single-control balanced water supply method for an ascending pipe, which comprises the following steps of: S1, calculating water inlet flows required by the ascending pipe in different coking stages according to the change conditions of raw gas temperature and flow of a coke oven in a coking period and in combination with the temperature requirement of an ascending pipe outlet on raw gas, and compiling a water inlet flow control program; s2, arranging an electromagnetic regulating valve and a flow meter on a water inlet pipe of the riser; s3, interlocking the frequency of the circulating pump with the pressure difference between the outlet pressure of the circulating pump and the steam pocket pressure to ensure that the pressure difference between the outlet pressure of the circulating pump and the steam pocket pressure is constant, so that the circulating pump supplies water at constant pressure difference; s4, coke pushing and coal charging time and a coking period in a coke pushing and coal charging planning program of the coke oven are added in an original ascending pipe operation program, the data are provided for an electromagnetic regulating valve of the ascending pipe, and the electromagnetic regulating valve receives the instruction and controls the coking period according to water inlet flow calculation values of different coking stages in a water inlet flow control program. The opening degree of the electromagnetic adjusting valve is adjusted so that the water inlet flow of the ascending pipe can meet the requirement, and balanced water supply is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery of coke oven riser pipes, and in particular to a method for single-control balanced water supply of riser pipes. Background Art

[0002] The raw coal gas coming out of the carbonization chamber of the coke oven and entering the riser heat exchanger is about 650-800℃. At present, coking enterprises generally use the traditional ammonia spraying method to cool it, which will lead to a large amount of waste heat resources cannot be utilized, resulting in serious waste of resources. With the development of waste heat recovery technology, many enterprises have adopted riser heat exchangers to recover the heat of raw coal gas, produce low-pressure and medium-pressure saturated steam, and recover the sensible heat of raw coal gas.

[0003] In recent years, the technology of waste heat recovery system for coke oven raw gas riser has gradually matured and become the standard for new coke ovens and renovated coke ovens in the coking industry. Because there are a large number of risers, all risers are basically operated in parallel. Although measures such as intermediate water inlet, step-by-step diameter reduction and orifice plate addition are taken to ensure the balanced water inlet of each group of parallel risers as much as possible, there is still the phenomenon of uneven water inlet of the riser, which is mainly manifested in that some risers have too little water inlet and occasional dry burning. In order to avoid dry burning of individual risers, the site has to increase the circulating water flow to meet the requirements (increase the flow by circulating pump), but if the riser has too much water inlet, there will be too much heat from the raw gas, resulting in low-temperature condensation of the raw gas, causing tar and slag on the riser, resulting in black smoke and other problems, affecting environmental protection. Moreover, during the coking process, the amount and temperature of raw gas produced by coal are different, and the composition of raw gas is also different. Even if the water inlet of a single riser is completely stable, it is inevitable that there will be relatively too much water inlet, which will cause problems such as tar and slag on the riser.

[0004] At present, the water inlet of the riser mainly relies on the stable circulation pump flow to supply water to all the riser pipes. Since all the riser pipes are connected in parallel, there are problems of water inlet at different distances and different pipeline arrangements, which will cause uneven water inlet to each riser. Insufficient water inlet will cause dry burning of the riser, while excessive water inlet will result in excessive heat removal, causing slagging and smoking in the riser. Moreover, the water inlet amount does not take into account the different water inlet amounts required for the riser at different times during the coking cycle.

[0005] In summary, the current riser system has a circulation flow rate that is too small, which will cause dry burning problems in some risers and affect steam production; although a large circulation flow rate can solve the dry burning problem, it increases the operating cost of the circulation pump, and a large flow rate will also result in excessive heat extraction, causing smoke in the riser. Summary of the invention

[0006] The purpose of the present invention is to provide a method for single-control balanced water supply to a riser pipe in view of the problem of uneven water supply in the current method of centralized water supply to the riser through a circulating pump. The method fully considers the changes in the coking cycle of the coke oven and changes the water inlet flow rate of the riser pipe according to the changes in the output and temperature of the raw gas during the coking cycle. This not only ensures the safe operation of the riser pipe, but also avoids the problems of lack of dry burning and slagging and smoking in the riser.

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

[0008] The present invention provides a method for single-control balanced water supply of a riser pipe, the method comprising the following specific steps:

[0009] S1. Prepare the water flow control program for each riser in a coking cycle:

[0010] According to the changes in the temperature and flow of raw gas in a coking cycle of the coke oven (there are empirical data, and the trends are basically the same), combined with the temperature requirements of the raw gas at the outlet of the riser, the required water inlet flow of the riser at different coking stages in the coking cycle is calculated; then, according to the calculation results of the required water inlet flow of the riser at different coking stages, the water inlet flow control program is compiled;

[0011] The coking cycle includes: coal loading stage, early coking stage, middle coking stage and late coking stage;

[0012] S2. Add an electromagnetic regulating valve and a flow meter on each riser to control the water inlet flow: install an electromagnetic regulating valve and a flow meter on the water inlet pipe of each riser;

[0013] S3. Set the circulating pump to supply water at constant pressure difference:

[0014] The frequency of the circulating pump is interlocked with the pressure difference between the circulating pump outlet pressure and the drum pressure, and the pressure difference between the circulating pump outlet pressure and the drum pressure is ensured to be constant through frequency conversion regulation, so that the circulating pump supplies water to the riser in a constant pressure difference manner;

[0015] S4. Recompile the operation program of the riser and connect it with the coke oven coking and coal charging planning program:

[0016] The coke pushing and coal loading time and coking cycle data in the coke oven coke pushing and coal loading planning program are added to the original riser operation program, and these data are read to provide instructions to the electromagnetic regulating valve on each riser. The electromagnetic regulating valve receives the instructions and adjusts the opening of the electromagnetic regulating valve according to the calculated value of the water inlet flow at different coking stages in the water inlet flow control program so that the water inlet flow of the riser meets the requirements and achieves balanced water supply.

[0017] Specifically, since the water inlet of the riser currently mainly relies on the stable circulation pump flow to centrally supply water to all the riser pipes, and since all the riser pipes are connected in parallel, the water inlet will be far and near and the pipeline layout will be different, which will inevitably cause the water inlet of each group of riser pipes to be uneven. If the water inlet of the riser is small, the riser will cause water shortage and dry burning, which will affect its service life and be unsafe; if the water inlet of the riser is too much, it will cause excessive heat extraction, resulting in low-temperature condensation of raw coal gas, causing tar hanging, slagging and black smoke problems in the riser, and the existing water inlet of the riser does not take into account the different water inlet requirements of the riser at different coking stages in the coking cycle.

[0018] Therefore, the present invention aims to solve the problem of uneven centralized water supply through a circulating pump, while taking into account the water demand of the riser in different coking stages. The present invention supplies variable water to the riser according to the coking cycle of the coke oven, which not only ensures the safe operation of the riser, but also avoids the problem of slagging and smoking.

[0019] Furthermore, a method for single-control balanced water supply of a riser is provided: Step S1 also simultaneously calculates the water inlet flow rate required for the riser at different coking stages after the coking cycle is extended, in preparation for use when the coking cycle is extended.

[0020] Specifically, if the coking cycle is significantly extended, the water flow rate required to enter the riser should also be reduced accordingly.

[0021] Furthermore, a method for single-control balanced water supply of a riser is provided: the raw gas temperature at the outlet of the riser in step S1 is required to be 480-520°C.

[0022] Furthermore, a method for single-control balanced water supply of a riser is provided: the electromagnetic regulating valve in step S2 is arranged downstream of the flow meter.

[0023] Furthermore, a method for single-control balanced water supply of a riser is provided: in step S2, the electromagnetic regulating valve is set to a minimum water inlet flow rate to avoid dry burning of the riser due to lack of water.

[0024] Specifically, the purpose of this design is to prevent the electromagnetic regulating valve from closing, thereby causing the riser to dry out due to lack of water, so the minimum flow rate of the regulating valve needs to be set.

[0025] Furthermore, a method for single-control balanced water supply of a riser is provided: a manual water inlet valve is also provided on the water inlet pipe, and is arranged upstream of the electromagnetic regulating valve and downstream of the flow meter.

[0026] Furthermore, a method for single-control balanced water supply of a riser is provided: a water outlet manual valve is provided on the water outlet pipe of the riser.

[0027] Furthermore, a method for single-control balanced water supply of a riser pipe is provided: the water outlet pipe is also connected to a relief pipe, and the relief pipe is provided with a relief valve.

[0028] Beneficial effects of the present invention:

[0029] (1) The method of the present invention can control the water inlet of a single riser, ensuring that each riser will not have the problem of dry burning due to lack of water, and the system is safer. At the same time, the method of the present invention fully considers the changes in the coking cycle of the coke oven, and changes the water inlet flow of the riser according to the changes in the output and temperature of the raw gas during the coking cycle. The water inlet changes according to the coking time to prevent excessive heat extraction, which leads to slagging and smoking in the riser.

[0030] (2) The method of the present invention also considers the effect of the overall extension of the coking cycle of the coke oven on the heat extraction of the riser system, and calculates the water inlet flow rate required for the riser at different coking stages after the coking cycle is extended, so as to prevent the problem of black smoke caused by excessive heat extraction after the coking cycle is extended.

[0031] (3) The method of the present invention is also designed to interlock the frequency of the circulation pump with the pressure difference between the circulation pump outlet pressure and the drum pressure, and to keep the pressure difference constant through frequency conversion regulation. This is because the flow entering a single riser changes with the coking cycle, and the required circulation flow of the whole furnace will also be different. If the frequency of the circulation pump is kept unchanged, the circulation pump outlet pressure will change, which will affect the regulation of the single riser. Therefore, it is necessary to maintain the circulation pump outlet pressure through frequency conversion, and change the original circulation pump constant supply flow to a constant pressure difference supply flow. At the same time, such a design can also reduce the circulation rate of the circulation pump, reduce the operating costs of the pump, and can also protect the circulation pump from being damaged by excessive load when it continues to operate at a constant supply flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0033] Figure 1 It is the raw gas temperature curve at the inlet of the riser during the coking cycle of the coke oven;

[0034] Figure 2 It is the flow rate of raw gas during the coking cycle of the coke oven (the amount of raw gas generated);

[0035] Figure 3 It is a schematic diagram of the structure of the riser in the present invention.

[0036] Markings in the figure: 1-rising pipe, 2-water inlet pipe, 3-electromagnetic regulating valve, 4-flow meter, 5-water inlet manual valve, 6-water outlet pipe, 7-water outlet manual valve, 8-drain pipe, 9-drain valve. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] like Figures 1 to 3 As shown, this embodiment 1 provides a method for single-control balanced water supply of a riser pipe, and the method includes the following specific steps:

[0040] S1. Prepare the water flow control program for each riser in a coking cycle:

[0041] According to the changes in the raw gas temperature and flow rate of the coke oven during a coking cycle (such as Figures 1-2 As shown in the figure, combined with the temperature requirement of 480-520℃ for the raw gas at the outlet of the riser 1 (if the raw gas temperature at the outlet of the riser 1 is lower than this temperature requirement, it is easy to cause low-temperature condensation of the raw gas, resulting in tar and slag on the riser 1, thus causing black smoke and other problems), the required water inlet flow rate of the riser 1 at different coking stages in the coking cycle is calculated;

[0042] At the same time, the required water inlet flow rate of the riser 1 at different coking stages after the coking cycle is extended is calculated in preparation for use when the coking cycle is extended;

[0043] Then, according to the calculation results of the required water inlet flow rate of the riser 1 at different coking stages, a water inlet flow rate control program is compiled;

[0044] The coking cycle includes: coal loading stage, early coking stage, middle coking stage and late coking stage;

[0045] S2. Add a solenoid regulating valve and flow meter to each riser to control the water flow:

[0046] An electromagnetic regulating valve 3 and a flow meter 4 are arranged on the water inlet pipe 2 of each riser 1; the electromagnetic regulating valve 3 is used to read and receive the instructions of the preset program. When the flow meter 4 detects that the water inlet flow rate is higher than the water inlet flow rate value set in the corresponding coking stage in the control program, the electromagnetic regulating valve 3 is closed, and vice versa. At the same time, in order to prevent the electromagnetic regulating valve 3 from being closed and causing the riser to dry out due to lack of water, the minimum flow rate of the electromagnetic regulating valve 3 needs to be set;

[0047] S3. Set the circulating pump to supply water at constant pressure difference:

[0048] The frequency of the circulating pump is interlocked with the pressure difference between the circulating pump outlet pressure and the drum pressure, and the pressure difference between the circulating pump outlet pressure and the drum pressure is ensured to be constant through frequency conversion regulation, so that the circulating pump supplies water to the riser 1 in a constant pressure difference manner; since the flow entering a single riser changes with the coking cycle, the required circulation flow of the whole furnace will also be different. If the frequency of the circulating pump is kept unchanged, the circulating pump outlet pressure will change, which will affect the regulation of the single riser. Therefore, it is necessary to maintain the circulating pump outlet pressure through frequency conversion, and change the original circulating pump constant supply flow to a constant pressure difference supply flow;

[0049] S4. Recompile the operation program of the riser and connect it with the coke oven coking and coal charging planning program:

[0050] The coke pushing and coal loading time and coking cycle data in the coke oven coke pushing and coal loading planning program are added to the original riser operation program, and these data are read to provide instructions to the electromagnetic regulating valve 3 on each riser 1. The electromagnetic regulating valve 3 receives the instructions and adjusts the opening of the electromagnetic regulating valve 3 according to the calculated value of the water inlet flow at different coking stages in the water inlet flow control program so that the water inlet flow of the riser 1 meets the requirements and achieves balanced water supply.

[0051] Specifically, in the above embodiment 1, the drum ( Figure 3 (not shown) saturated deoxygenated water can be supplied to the riser 1 through a circulating pump. After the deoxygenated water completes heat exchange with the raw coal gas in the riser, the steam-water mixture is led back to the steam drum through the outlet pipe 6 for steam-water separation, and the generated low-pressure and medium-pressure saturated steam is sent out from the upper part of the steam drum.

[0052] Since the amount and temperature of raw gas produced by coal change during the coking process and the composition of the raw gas is also different, the control method of the present invention fully considers the changes of coal in the coke oven during the coking process, and controls the water inlet flow of each riser in real time according to the changes in the output and temperature of the raw gas during the coking cycle, so that the water inlet volume changes according to the coking time, preventing excessive heat extraction, which leads to low-temperature condensation of the raw gas at the riser outlet, causing tar and slag to form on the riser, thereby causing problems such as black smoke, affecting environmental protection.

[0053] The above are preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A method for balanced water supply by single control of a rising pipe, characterized in that: The method comprises the following steps: S1. Prepare the water flow control program for each riser in a coking cycle: According to the changes in the temperature and flow rate of the raw gas in the coking oven during a coking cycle, and in combination with the temperature requirements of the raw gas at the outlet of the riser (1), the required water inlet flow rate of the riser (1) at different coking stages during the coking cycle is calculated; Then, according to the calculation results of the required water inlet flow rate of the riser (1) at different coking stages, a water inlet flow rate control program is compiled; The coking cycle includes: coal loading stage, early coking stage, middle coking stage and late coking stage; S2. Add a solenoid regulating valve and flow meter to each riser to control the water flow: An electromagnetic regulating valve (3) and a flow meter (4) are arranged on the water inlet pipe (2) of each riser (1); S3. Set the circulating pump to supply water at constant pressure difference: The frequency of the circulating pump is interlocked with the pressure difference between the circulating pump outlet pressure and the drum pressure, and the pressure difference between the circulating pump outlet pressure and the drum pressure is ensured to be constant through frequency conversion regulation, so that the circulating pump supplies water to the riser (1) in a constant pressure difference manner; S4. Recompile the operation program of the riser and connect it with the coke oven coking and coal charging planning program: The coke pushing and coal loading time and coking cycle data in the coke pushing and coal loading planning program of the coke oven are added to the original riser operation program, and these data are used to provide instructions to the electromagnetic regulating valve (3) on each riser (1). The electromagnetic regulating valve (3) receives the instructions and adjusts the opening of the electromagnetic regulating valve (3) according to the calculated value of the water inlet flow at different coking stages in the water inlet flow control program so that the water inlet flow of the riser (1) meets the requirements, thereby achieving balanced water supply.

2. A method for balanced water supply by single control of a rising pipe according to claim 1, characterized in that: Step S1 also simultaneously calculates the water inlet flow rate required for the riser (1) at different coking stages after the coking cycle is extended, in preparation for use when the coking cycle is extended.

3. A method for balanced water supply by single control of a rising pipe according to claim 1 or 2, characterized in that: The raw gas temperature at the outlet of the riser (1) in step S1 is required to be 480-520°C.

4. The method for balanced water supply by single control of a rising pipe according to claim 1, characterized in that: In step S2, the electromagnetic regulating valve (3) is arranged downstream of the flow meter (4).

5. The method for balanced water supply by single control of a rising pipe according to claim 1, characterized in that: In step S2, the electromagnetic regulating valve (3) is set to a minimum water inlet flow rate to prevent the riser (1) from drying out due to lack of water.

6. The method for balanced water supply by single control of a rising pipe according to claim 1, characterized in that: The water inlet pipe (2) is also provided with a water inlet manual valve (5), which is arranged upstream of the electromagnetic regulating valve (3) and downstream of the flow meter (4).

7. A method for balanced water supply by single control of a rising pipe according to claim 1, characterized in that: A water outlet manual valve (7) is provided on the water outlet pipe (6) of the rising pipe (1).

8. A method for balanced water supply by single control of a rising pipe according to claim 7, characterized in that: The water outlet pipe (6) is also connected to a relief pipe (8), and the relief pipe (8) is provided with a relief valve (9).

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