Energy-saving configuration method of hot-rolling and finishing descaling device

Abstract

The present application relates to a kind of energy-saving configuration method of hot rolling finishing descaling equipment, the method comprises the following steps: step 1: according to product outline and process scheme or production performance query finishing 2 group descaling, 1 group descaling and not open descaling process proportion a1, a2 and a3;Step 2: alternative solution is proposed, according to descaling pump and descaling header one-to-one, 2 descaling pumps are configured, and relevant descaling parameters are determined.The present application achieves energy-saving effect on the basis of ensuring that descaling effect does not decrease under various production conditions.On this basis, a method for judging whether the alternative solution is economical is proposed, thereby guiding the determination of the final solution and achieving the effect of optimization.

Description

TECHNICAL FIELD

[0001] The application relates to an energy-saving configuration method, in particular to an energy-saving configuration method of a hot-rolling finishing-rolling descaling device, and belongs to the technical field of the hot-rolling finishing-rolling descaling device. BACKGROUND

[0002] At present, the hot-rolling descaling system gradually develops from a rough-rolling and finishing-rolling shared descaling system to a rough-rolling and finishing-rolling separated and nearby arrangement to reduce the pressure loss caused by long-distance transmission. The descaling device mainly comprises a descaling pump, a descaling motor and the like. The descaling pump and the motor are matched, the descaling pump model is determined, and the corresponding motor is matched. The role of the potential accumulator is to store the high-pressure descaling water by using the gap without descaling on site, and when the on-site descaling is put into operation, the stored high-pressure water is used as the supplement of the descaling pump to maintain the stability of the pressure. The rough-rolling descaling water consumption is pulse type, the average consumption level is not high, but the stage consumption is very large, and the capacity of the potential accumulator can be increased to reduce the descaling pressure fluctuation and the descaling capacity. The finishing-rolling descaling consumption is relatively stable, the same steel is rolled, the descaling consumption is generally the same from the descaling opening to the descaling closing. Generally, the finishing-rolling high-pressure descaling is configured with one descaling pump (not including a backup), 2 groups of descaling headers on site are supplied, the number and model of the descaling nozzles of the 2 groups of headers are basically the same, and the descaling water consumption is basically the same. Only two working modes of opening 2 groups and opening 1 group exist when working. The finishing-rolling inter-stand descaling is generally configured with one descaling pump (not including a backup), 2 groups of headers on site are supplied, and the parameters of the two groups are basically the same. Generally, there are 3 working modes of opening 2 groups, opening 1 group and not opening. The general hot-rolling high-pressure descaling pump requires a pressure of 20 MPa or above, and the motor power is generally more than 2000 Kw. The medium-pressure descaling pump requires a pressure of 10 MPa or above, and the motor power is generally more than 1000 Kw. After starting, the motor works at full power, and the power consumption is very large. The conventional design finishing-rolling high-pressure descaling pump needs to meet the requirement of the maximum descaling on site, that is, 2 groups of headers are simultaneously opened. The inter-stand descaling also needs to meet the requirement of the maximum descaling supply on site, that is, 2 groups of headers are simultaneously opened. This descaling parameter configuration method is relatively high in efficiency only when 2 groups of headers on site are simultaneously opened. Energy is wasted at other times. In general, this selection method will cause a lot of energy waste as long as 2 groups of descaling headers on site are not simultaneously opened. Moreover, due to the requirement of energy saving and weight reduction, the proportion of thin specifications will be more and more, and the descaling opening group number of the thin specifications is generally less to ensure the rolling stability. This selection method will cause more and more waste in the long term. Therefore, there is an urgent need for a new scheme to solve the above technical problems.

[0003] In view of this problem, steel plants and colleges and universities carry out work. According to the keyword "descaling pump", 10 patents are searched in the patent information comprehensive service platform. Chinese patent CN200710202465.5 hot continuous rolling production line high pressure water descaling system introduces a kind of 25-40MPa high pressure descaling system, Chinese patent CN201711478455.4 a kind of control method of descaling system introduces a kind of 25-30MPa variable frequency high pressure descaling system control method. At present, there is no solution to solve the above problems. SUMMARY

[0004] The present application is just for the problems existing in the prior art, and provides an energy-saving configuration method of hot rolling finishing descaling equipment. The technical scheme provides an energy-saving alternative configuration scheme of hot rolling finishing descaling equipment. The alternative configuration scheme mainly solves the problems of power waste when the two groups of descaling headers of the existing finishing descaling system are not started at the same time during rolling thin gauge products, and power waste during roll changing and temporary fault non-production time. The application achieves energy-saving effect on the basis of ensuring that the descaling effect is not reduced under various production conditions. On this basis, a method for judging whether the alternative scheme has economic efficiency is proposed, thereby guiding the determination of the final scheme and achieving the effect of optimization.

[0005] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows: an energy-saving configuration method of hot rolling finishing descaling equipment, the method comprising the following steps:

[0006] Step 1: according to the product outline and process scheme or production performance, the process proportions a1, a2 and a3 of finishing 2-group descaling, 1-group descaling and no descaling are queried; wherein a1 is the proportion of 2-group descaling process used, wherein a2 is the proportion of 1-group descaling process used, wherein a3 is the proportion of no descaling process used,

[0007] Wherein a1+a2+a3=1;

[0008] The finishing descaling has only two process requirements of 2-group descaling and 1-group descaling, and the inter-stand descaling has three process requirements of 2-group descaling, 1-group descaling and no descaling;

[0009] Step 2: propose an alternative scheme, configure 2 descaling pumps according to one-to-one of descaling pump and descaling header, and determine the related descaling parameter system pressure P=P0+Pi;

[0010] Flow M2=M0*k / 2;

[0011] Select the motor according to P and M2, and the motor power is w2;

[0012] Wherein: P, P0, Pi represent descaling pump system pressure, descaling end pressure and system pressure drop respectively. Pi is generally taken as 2-4 MPa. M2, M0, k represent system flow, descaling maximum dosage and surplus coefficient respectively. M2 is generally selected from common specifications, and k is generally taken as 1.1-1.4.

[0013] As an improvement of the application, the descaling pump is a multi-stage centrifugal descaling pump, the descaling motor has a variable frequency speed regulation function, and one-way valves are arranged at the outlets of each descaling pump to prevent backflow of descaling water during low frequency operation.

[0014] The economic efficiency of the alternative scheme is evaluated,

[0015] Comparison conditions:

[0016] The alternative scheme investment increases b;

[0017] The standard investment return rate is considered according to c, and if it exceeds c, the investment can be made, otherwise the investment cannot be made;

[0018] The annual working time is considered according to f, wherein the production time is f1, the non-production time (roll replacement and temporary failure) is f2, and here f=f1+f2. The electricity price is calculated according to g;

[0019] In order to ensure that the descaling is started at any time, the motor frequency is considered according to d when not in use, and the frequency of the variable frequency is considered according to e when in use. The motor consumption is considered as (d / e) 2 Proportion calculation;

[0020] The conventional scheme consumes W1=w1 per hour;

[0021] The alternative scheme consumes W2=2*w2*a1+w2*(1+(d / e) 2 )*a2+2*w2*(d / e) 2 *a3 per hour during production;

[0022] The alternative scheme consumes W3=2*w2*(d / e) 2 per hour during non-production;

[0023] The alternative scheme saves W1*f-W2*f1-W3*f2*g per year;

[0024] The alternative scheme investment return is (W1*f-W2*f1-W3*f2)*g / B;

[0025] According to the comparison of the alternative scheme investment return rate and the standard investment return rate, it is determined whether the alternative scheme can be selected.

[0026] Compared with the prior art, the application has the following advantages: in the alternative scheme, the alternative scheme is selected on the premise that the alternative scheme is economical. Since the descaling pump is one-to-one corresponding to the header, the number of high-speed running (frequency 50HZ) descaling pumps can be determined according to the number of groups of the descaling header in the field, and the other descaling pumps run at low speed (frequency 20HZ). Compared with the original scheme, the power consumption is saved. When two groups of the descaling in the field are opened, two pumps run at a frequency of 50HZ, which is basically equivalent to or slightly increases than the original scheme; when one group in the field is opened, one pump runs at a frequency of 50HZ, and the other pump can run at a frequency of 20HZ, and the power consumption of the pump running at a frequency of 20HZ is 16%, which can generally save 40% of electricity; when the field is not opened, two pumps run at a frequency of 20HZ, which can save more than 80% of electricity. The application can achieve the designed descaling pressure and the original descaling effect in the field. In the scheme, firstly, the accumulator is cancelled to prevent the low water level of the accumulator (causing the decrease of the descaling pressure and the flow); secondly, the high-pressure water flow orifice plate is used to reduce the pressure to act as a pre-flushing water to prevent the water hammer phenomenon without the accumulator. DETAILED DESCRIPTION

[0027] In order to deepen the understanding of the application, the following will be described in detail in combination with examples.

[0028] Example 1: An energy-saving configuration method of a hot rolling finishing descaling device, the method comprising the following steps:

[0029] Step 1: According to the product outline and the process scheme or the production performance, the finishing descaling process of 2 groups, the finishing descaling process of 1 group and the descaling process without opening are queried to obtain the process proportions a1, a2 and a3; wherein a1 is the proportion of the process of 2 groups of descaling, wherein a2 is the proportion of the process of 1 group of descaling, wherein a3 is the proportion of the process of not opening descaling,

[0030] Wherein a1+a2+a3=1

[0031] The finishing descaling has only two process requirements of 2 groups of descaling and 1 group of descaling, and the inter-stand descaling has three process requirements of 2 groups of descaling, 1 group of descaling and no descaling

[0032] Step 2: An alternative scheme is proposed, 2 descaling pumps are configured according to the one-to-one correspondence between the descaling pump and the descaling header, and the related descaling parameter system pressure P is determined as P0+Pi;

[0033] The flow M2 is M0*k / 2;

[0034] The motor power w2 is selected according to P and M2;

[0035] Wherein: P, P0, Pi respectively represent the descaling pump system pressure, descaling end pressure and system pressure drop. Pi is generally taken 2-4 MPa M2, M0, k respectively represent the system flow, descaling maximum dosage and the surplus coefficient. M2 generally needs to be selected in the commonly used specifications, k is generally taken 1.1-1.4.

[0036] Wherein, the descaling pump is a multi-stage centrifugal descaling pump, the descaling motor has a variable frequency speed regulation function, and one-way valves are configured at each descaling pump outlet to prevent descaling water from flowing back when running at a low frequency. Specific embodiment 1:

[0038] Taking the finishing descaling box of 1780 rolling line as an example, 1780 hot rolling finishing has two descaling headers, and the end system pressure is required to be 20 MPa, the flow rate of each group is 143 t / h, the maximum flow rate is 286 t / h, and the preferred configuration method is as follows:

[0039] 1. According to the production performance, the finishing 2 descaling, 1 descaling and no descaling process ratio of 55%, 45% and 0 is inquired;

[0040] 2. According to one-to-two of the descaling pump and the descaling header, the maximum demand of the process descaling water, one descaling pump is configured, and the related descaling parameters are determined

[0041] System pressure P = 20 + 3 = 23 (MPa);

[0042] Flow rate M1 = 286 * 1.224 = 350 (t / h);

[0043] According to P, M1, the motor is selected, and the motor power is 3500 (KW);

[0044] Wherein: Pi is taken as 3 MPa, and k is taken as 1.224;

[0045] 3. An alternative scheme is proposed, one-to-one of the descaling pump and the descaling header, two descaling pumps are configured, and the related descaling parameters are determined System pressure P = 20 + 3 = 23 (MPa);

[0046] Flow rate M2 = 286 / 2 * 1.259 = 180 (t / h);

[0047] According to P, M2, the motor is selected, and the motor power is 1800 (KW);

[0048] Wherein: Pi is taken as 3 MPa, and k is taken as 1.259;

[0049] 4. Economic evaluation of the alternative scheme;

[0050] Comparison conditions:

[0051] The investment of the alternative scheme is increased by 800 million yuan;

[0052] The standard investment return rate is considered to be 20% per year, and more than 20% can be invested, otherwise it cannot be invested;

[0053] The annual working time is considered to be 7000 hours, of which the production time is 6500 hours, and the non-production time such as roll changing and temporary failure is 500 hours.

[0054] The electricity price is calculated at 0.8 yuan / degree;

[0055] To ensure that the descaling is ready to start at any time, the motor frequency is considered to be 20HZ when not in use, and the frequency is considered to be 50HZ when in use. The motor consumption is calculated by the coefficient of 0.16((20 / 50) 2 );

[0056] The conventional scheme consumes electricity per hour: W1=3500( degrees);

[0057] The alternative scheme consumes electricity per hour during production: W2=2*1800*55%+1800*(1+0.16)*45%=2919.6( degrees);

[0058] The alternative scheme consumes electricity per hour during non-production: W3=2*1800*0.16=576( degrees);

[0059] The alternative scheme saves electricity annually: (3500*7000-2919.6*6500-576*500)*0.8=4187680( yuan);

[0060] The alternative scheme investment return: 4187680 / 8000000=52.3%;

[0061] The preferred standby scheme.

[0062] 5、The descaling pump involved in the alternative scheme is a multi-stage centrifugal descaling pump.

[0063] 6、The descaling motor involved in the alternative scheme has a variable frequency speed regulation function Specific embodiment 2:

[0065] Taking the interstand of the 1780 rolling line as an example, there are 2 descaling points for the 1780 hot rolling interstand, and the required end pressure is 11MPa, the flow rate of each group is 103t / h, and the preferred configuration method is as follows:

[0066] 1、According to the production performance, the descaling of the finishing 2 groups, the descaling of the finishing 1 group and the descaling process ratio of 43%, 31% and 26% are inquired;

[0067] 2、According to the one-to-two relationship between the descaling pump and the descaling header, the maximum demand for process descaling water, 1 descaling pump is configured, and the related descaling parameters are determined;

[0068] System pressure P = 11 + 2 = 13 (MPa);

[0069] Flow M1 = 206 * 1.214 = 250 (t / h);

[0070] Select motor according to P, M1, motor power is 1400 (KW);

[0071] Wherein: Pi takes 2 MPa, k takes 1.214;

[0072] 3, put forward alternative, except scale pump and scale removal manifold one to one, configure 2 scale removal pumps, and determine the relevant scale removal parameters;

[0073] System pressure P = 20 + 3 = 23 (MPa);

[0074] Flow M2 = 206 / 2 * 1.359 = 140 (t / h);

[0075] Select motor according to P, M2, motor power is 900 (KW);

[0076] Wherein: Pi takes 2 MPa, k takes 1.359;

[0077] 4, economic evaluation of alternative;

[0078] Comparison conditions:

[0079] Alternative investment increases by 5 million yuan;

[0080] The standard return on investment is considered to be 20% per year, more than 20% can be invested, otherwise not;

[0081] The annual working time is considered to be 7000 hours, the other production time is 6500 hours, and the non-production time such as roll changing and temporary failure is 500 hours.

[0082] The electricity price is calculated at 0.8 yuan per degree;

[0083] To ensure that the scale removal has starting conditions at any time, the motor frequency is considered to be 20HZ when not in use, and the frequency is considered to be 50HZ when in use. The motor consumption is calculated by 0.16 ((20 / 50) 2 ) coefficient;

[0084] The conventional scheme consumes W1 = 1400 (degree) per hour;

[0085] The alternative scheme consumes W2 = 2 * 900 * 43% + 900 * (1 + 0.16) * 31% + 2 * 900 * 0.16 * 26% = 1172.52 (degree) per hour;

[0086] Alternative non-production hourly power consumption: W3 = 2 * 900 * 0.16 = 288 (degrees);

[0087] Alternative annual electricity saving benefit: (1400 * 7000 - 1172.52 * 6500 - 288 * 500) * 0.8 = 1627696 (yuan);

[0088] Alternative investment return: 1627696 / 5000000 = 32.6%;

[0089] Preferred alternative solution.

[0090] 5、The descaling pump involved in the alternative solution is a multi-stage centrifugal descaling pump.

[0091] 6、The descaling motor involved in the alternative solution has a variable frequency speed regulation function.

[0092] It should be noted that the above examples are not intended to limit the scope of protection of the present application, and any equivalent transformations or substitutions made on the basis of the above technical solutions fall within the scope of protection of the claims of the present application.

Claims

1. A method of energy saving configuration of a hot-rolling finishing descaling device, characterized in that, The method comprises the following steps: Step 1: according to the product outline and process scheme or production performance, the descaling process proportions a1, a2 and a3 of the finishing group 2 descaling, the group 1 descaling and the non-descale are inquired; wherein a1 is the proportion used by the group 2 descaling process, wherein a2 is the proportion used by the group 1 descaling process, wherein a3 is the proportion used by the non-descale process, Step 2: an alternative scheme is proposed, 2 descaling pumps are configured according to the one-to-one relationship between the descaling pump and the descaling header, and the related descaling parameters are determined; In step 1, Wherein a1+a2+a3=1; The finishing descaling has only two process requirements of the group 2 descaling and the group 1 descaling, and the inter-stand descaling has three process requirements of the group 2 descaling, the group 1 descaling and the non-descale; In step 2, The system pressure P=P0+Pi; The flow M2=M0*k / 2; The descaling motor is selected according to P and M2, and the motor power is w2; Wherein: P, P0 and Pi respectively represent the descaling pump system pressure, the descaling end pressure and the system pressure drop, Pi is 2-4 MPa, M2, M0 and k respectively represent the system flow, the maximum descaling amount and the surplus coefficient, M2 is selected in the commonly used specifications, and k is 1.1-1.4; The descaling pump is a multi-stage centrifugal descaling pump; The descaling motor has a variable frequency speed regulation function, Each descaling pump outlet is provided with a one-way valve.