CN105710143A - Energy-saving modification method for hot rolling high-pressure water scale removing system based on energy accumulator and high-voltage inverter - Google Patents

Abstract

The invention discloses an energy-saving modification method for a hot rolling high-pressure water scale removing system based on an energy accumulator and a high-voltage inverter. The method includes the following specific steps that firstly, the energy accumulator is selected according to the scale removing water consumption in a rolling period; secondly, the high-voltage inverter is selected according to the speed increase and decrease time of a scale removing pump and the rotational inertia of a motor; thirdly, the energy accumulator, the high-voltage inverter, the scale removing pump and the motor are connected and matched; and fourthly, the scale removing pump provided with the energy accumulator and the high-voltage inverter is put into production and use, and energy is saved. The method has the beneficial effects that the high-voltage inverter combined with an energy accumulator system is adopted as an energy-saving modification main device, the high-voltage inverter can use the scale removing interval for speed reduction to achieve energy-saving modification, the purposes of energy consumption reduction, energy conservation and emission reduction can be better achieved on the premise that the requirements of the production technology are met, and a whole energy-saving modification system with the high-voltage inverter and the energy accumulator is formed.

Description

A kind of energy-conserving reconstruction method of the hot rolling high-pressure water descaling system based on accumulator and high voltage converter

Technical field

The invention belongs to the technical field of hot rolling high-pressure water descaling system reducing energy consumption, be specifically related to the energy-conserving reconstruction method of a kind of hot rolling high-pressure water descaling system based on accumulator and high voltage converter.

Background technology

On modern hot-rolled strip production line, high-pressure water descaling technology, as the important means improving plate surface quality, is applied increasingly extensive.High-pressure water descaling system institute gas-distributing motor is the power consumption rich and influential family that steel mill is main, and the long-time power frequency constant-speed operation of high-pressure water descaling motor of current domestic many steel mills, waste of energy is very big.As time goes on, the development in epoch, the aggravation increasingly of steel market competition, market is saturated gradually, and the product quality of steel mill is required more and more higher by user.The present market competition, one is the competition of product quality, two is the competition of production cost, although producing high-quality product can promote its market competitiveness, but energy-saving and cost-reducing be also current each iron and steel enterprise must in the face of and problem demanding prompt solution, therefore, traditional high-pressure water descaling system is carried out that reducing energy consumption is very necessary and the energy saving space is very big.

Current domestic Pressure Water Scale Removing mainly has two ways: 1) dephosphorization pump group+accumulator composition descaling system；In this system, dephosphorization pump group water supply capacity mates with multiple spot de-scaling water consumption simultaneously, meets de-scaling needs；Accumulator is only used for balance system pressure, supplementary short time spike water consumption, suction line vibrations and makes up pipe valve leakage.2) dephosphorization pump group directly supplies water formation descaling system；In this system, main pump group water supply capacity is directly and de-scaling point necessary flow, pressure match, and the changes in flow rate in de-scaling interval time is controlled by the variable control device of pump group.

Descaling pump power frequency constant-speed operation all the time in the traditional design of the above two kinds of system, in most cases the operating condition of hot rolling line is likely to have multiple, de-scaling requirement and water requirement under different operating modes are usually different, and system is typically all the operating condition design maximum according to de-scaling water demand, this has resulted in the serious waste of system energy.

Medium Voltage Variable Frequency Speed Regulation Technology is through development for many years and application, and the advantage in speed adjusting performance, power savings and extension device service life etc. obtains sufficient embodiment.Therefore variable-frequency control technique energy-saving application in hot rolling high-pressure water descaling system is also that situation is become.

The operation principle of hot rolling high-pressure water descaling system and system composition determine that its Frequency Conversion Modification must combine with technique, consider from system entirety de-scaling rhythm.Simple adopts the pattern increasing converter, utilizes dephosphorization interval reduction of speed to reach energy-conservation purpose.Often do not reach in actual use anticipation energy-saving effect or transformation after be difficult to meet technological requirement, it is impossible to reach anticipation phosphor-removing effect.

Summary of the invention

The many employings of Frequency Conversion Modification of current high-pressure water descaling scene increase merely high voltage converter mode, this is done so that energy consumption becomes big, based on this problem, the present invention proposes the energy-conserving reconstruction method of a kind of hot rolling high-pressure water descaling system based on accumulator and high voltage converter, specifically comprises the following steps that

Step one, choose accumulator according to the de-scaling water consumption in the rolling cycle；

Step 101, according to rolling time-scale determine one rolling the dephosphorization cycle；

The rolling dephosphorization cycle includes time and the dephosphorization intermittent time of each dephosphorization point；

Step 102, determine the dephosphorization flow of each dephosphorization point in the whole rolling dephosphorization cycle, and calculate theoretical total water consumption；

For certain line, according to the dephosphorization flow of each dephosphorization point and de-scaling time, calculate the water consumption of each dephosphorization point；Thus the theoretical total water consumption calculated in the rolling dephosphorization cycle；

Step 103, determine de-scaling point overlapping in the rolling dephosphorization cycle, and calculate the water consumption of each overlapping de-scaling point；

The water consumption of each overlapping de-scaling point is: the flow of overlapping dephosphorization point and be multiplied by the overlapping dephosphorization time；

Step 104, judge the de-scaling flow of each overlapping dephosphorization point and whether more than the flow of dephosphorization pump, if it is, dephosphorization pump and the common dephosphorization of accumulator, the otherwise independent dephosphorization of dephosphorization pump；

Step 105, the dephosphorization flow rate calculation motorised volume of accumulator within a rolling dephosphorization cycle provided according to accumulator；

The motorised volume of accumulator includes the liquid level of accumulator and reaches the output of individually dephosphorization after the upper limit, and accumulator participates in the output of common dephosphorization；

Step 106, according to the motorised volume of accumulator and gas adiabatic equation law, calculate accumulator affects the gas volume of gas exchange under stress in limited time for the resistance of ducting；

Ideal gas adiabatic equation law: P*V=C

The wherein volume of P to be the pressure of ideal gas, V be ideal gas；C is constant.

Step 107, accumulator remove 90% according to gas volume and obtain accumulator actual demand value, are worth according to the actual requirements, choose accumulator gas tank and air hydraulic cylinder quantity.

Step 2, choose high voltage converter according to the lifting speed time of dephosphorization pump and the rotary inertia of motor；

Step 201, calculate Rated motor output torque T according to the rated power of motor and rated speed_e；

It is calculated as follows:

$T_e=9550\frac{P_e}{n_e}$

P_eFor the rated power of motor, n_eRated speed for motor；

Step 202, calculate motor angular velocity ω according to the rated speed of motor；

ω=2 π * n_e/60

Step 203, calculate the torque capacity in dephosphorization pump and motor accelerator and the minimum torque in moderating process respectively；

The required torque capacity T provided of converter in accelerator_max:

$T_{max}=J{\frac{d\mathrm{\ω}}{dt}}_{+}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{+}+K\mathrm{\ω}$

J is the rotary inertia sum of dephosphorization pump and motor, T_LFor load torque: T_L=K ω=K*2 π * n_e/ 60；The torque of K representation unit radian.

The required minimum torque T provided of converter in moderating process_min:

$T_{\min }=J{\frac{d\mathrm{\ω}}{dt}}_{-}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{-}+K\mathrm{\ω}$

Step 204, ratio according to torque capacity with Rated motor torque, and minimum torque chooses high voltage converter；

By calculating, the ratio according to torque capacity in accelerator with Rated motor torqueValue, choose satisfactory high voltage converter, calculate the minimum torque T of the high voltage converter chosen simultaneously_minMeet not for negative torque；

Step 3, by accumulator, high voltage converter, dephosphorization pump and motor are attached coupling；

Particularly as follows: host computer connects PLC, PLC connects high voltage converter by serial gateway, high voltage converter connects motor, and motor connects dephosphorization pump, and dephosphorization pump connects accumulator and dephosphorization pipeline simultaneously；High voltage converter and accumulator coherent signal all enter PLC system, high voltage converter control motor and drive dephosphorization pump and accumulator jointly to complete dephosphorization.

Step 4, the dephosphorization pump that have matched accumulator and high voltage converter is put into production use, it is achieved energy-conservation；

Concretely comprise the following steps:

Step 401, rolling the dephosphorization cycle in, first dephosphorization pump high-speed cruising is that accumulator carries out moisturizing；

Step 402, judging whether run into dephosphorization point in moisturizing process, if run into, entering step 403, otherwise, dephosphorization pump keeps high-speed cruising, for accumulator moisturizing, enters step 405；

Step 403, determining whether that the dephosphorization flow of dephosphorization point is whether more than the flow of dephosphorization pump, if it is, accumulator and dephosphorization pump carry out dephosphorization for overlapping dephosphorization point simultaneously, otherwise, dephosphorization pump is individually for dephosphorization point dephosphorization；

Step 404, complete the dephosphorization of each dephosphorization point after, dephosphorization pump keeps high-speed cruising, is accumulator moisturizing in dephosphorization gap；

Step 405, when accumulator liquid level reaches upper work liquid level or pressure reaches the upper limit, liquid level detection device output signal to PLC, PLC control high voltage converter make dephosphorization pump fall-back；

While step 406, dephosphorization pump keep low cruise, accumulator is individually for dephosphorization point and carries out dephosphorization；

Step 407 is until accumulator liquid level reaches lower work liquid-level pressure when reaching lower limit, and liquid level detection device outputs signal to PLC, PLC and controls high voltage converter, and high voltage converter controls dephosphorization pump fall forward, for accumulator moisturizing, enters the next dephosphorization cycle.

It is an advantage of the current invention that: the present invention adopts the high voltage converter in conjunction with accumulator system as the main equipment of reducing energy consumption, make high voltage converter, dephosphorization gap reduction of speed is utilized to reach reducing energy consumption, can realize better reducing energy consumption under the premise meeting production technology, the purpose of energy-saving and emission-reduction, defines high voltage converter and adds the whole energy modernization system of accumulator.

Accompanying drawing explanation

Fig. 1 is the present invention energy-conserving reconstruction method flow chart based on the hot rolling high-pressure water descaling system of accumulator and high voltage converter；

Fig. 2 is that the present invention chooses the method flow diagram of accumulator according to the de-scaling water consumption in the rolling cycle；

Fig. 3 is that the present invention chooses high voltage converter method flow diagram according to dephosphorization pump and motor；

Fig. 4 is that the present invention will have matched the dephosphorization pump work flow chart of accumulator and high voltage converter；

Fig. 5 is that the present invention determines rolling cycle schematic diagram according to water under high pressure dephosphorization sequential chart；

Fig. 6 is accumulator of the present invention, high voltage converter, and dephosphorization pump and motor are attached coupling schematic diagram.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is described in further detail.

The energy-conserving reconstruction method of a kind of hot rolling high-pressure water descaling system based on accumulator and high voltage converter of the present invention, utilize accumulator and high voltage converter as the main equipment of reducing energy consumption, high voltage converter reducing energy consumption is made to realize better reducing energy consumption, the purpose of energy-saving and emission-reduction under the premise meeting production technology.

As it is shown in figure 1, specifically comprise the following steps that

Step one, choose accumulator according to the de-scaling water consumption in the rolling cycle；

Concrete steps are as in figure 2 it is shown, as follows:

Step 101, according to rolling time-scale determine one rolling the dephosphorization cycle；

The rolling dephosphorization cycle includes time and the dephosphorization intermittent time of each dephosphorization point；

Step 102, determine the dephosphorization flow of each dephosphorization point in the whole rolling dephosphorization cycle, and calculate theoretical total water consumption；

For certain line, according to the dephosphorization flow of each dephosphorization point and de-scaling time, calculate the water consumption of each dephosphorization point；Thus the theoretical total water consumption calculated in the rolling dephosphorization cycle and average water consumption；

Step 103, determine de-scaling point overlapping in the rolling dephosphorization cycle, and calculate the water consumption of each overlapping de-scaling point；

Concretely comprise the following steps: first, calculate and repeat the dephosphorization point flow sum that dephosphorization point is corresponding, by dephosphorization point flow with compare with the actual flow of descaling pump, if dephosphorization point flow and the actual flow less than or equal to descaling pump, according to the flow of overlapping dephosphorization point be multiplied by overlapping dephosphorization Time Calculation overlap water consumption；Otherwise, dephosphorization point flow and the actual flow more than descaling pump, according to being multiplied by dephosphorization point flow the overlapping time of overlapping dephosphorization point and calculating overlapping water consumption；

Step 104, judge the de-scaling flow of each overlapping dephosphorization point and whether more than the flow of dephosphorization pump, if it is, dephosphorization pump and the common dephosphorization of accumulator, the otherwise independent dephosphorization of dephosphorization pump；

Step 105, the dephosphorization flow rate calculation motorised volume of accumulator within a rolling dephosphorization cycle provided according to accumulator；

Roll in the dephosphorization cycle at one, dephosphorization pump is the high-speed cruising t second first, moisturizing is carried out for accumulator, when the dephosphorization flow value sum of overlapping dephosphorization point is more than the flow of dephosphorization pump, then accumulator and dephosphorization pump carry out dephosphorization for overlapping dephosphorization point simultaneously, otherwise, dephosphorization pump keeps high-speed cruising, run into dephosphorization point and carry out dephosphorization, utilizing dephosphorization gap for accumulator moisturizing, when converter runs the time period for energy-conservation consideration reduction of speed tremendously low frequency rate, dephosphorization pump minimum flow valve is closed, dephosphorization pumping plant no longer exports, and is now responsible for dephosphorization by accumulator system.The total water consumption of overlapping dephosphorization point rejects the dephosphorization pump output flow at overlap point, and remainder is namely as the output of accumulator.

The output of dephosphorization pump is multiplied by the de-scaling time by the actual flow of dephosphorization pump and obtains；The de-scaling time includes t second high-speed cruising time, accumulator and dephosphorization pump and carries out the time of dephosphorization simultaneously for overlapping dephosphorization point；

Step 106, according to the motorised volume of accumulator and gas adiabatic equation law, calculate accumulator affects the gas volume of gas exchange under stress in limited time for the resistance of ducting；

Ideal gas adiabatic equation law: P*V=C

The wherein volume of P to be the pressure of ideal gas, V be ideal gas；C is constant, and namely after the long-pending and dephosphorization of the pressure volume before dephosphorization, the long-pending of pressure volume is a definite value (in the ideal situation, being left out system loss)

Before dephosphorization, in accumulator system, liquid volume is big, and the volume V of gas is little, and pressure P is big, and after dephosphorization terminates, liquid level declines, and gas volume V increases, but pressure V reduces simultaneously；

So volume V=C after pressure P* dephosphorization after dephosphorization fore pressure p* dephosphorization front volume V=dephosphorization.

Step 107, accumulator remove 90% according to gas volume and obtain accumulator actual demand value, are worth according to the actual requirements, choose accumulator gas tank and air hydraulic cylinder quantity.

Step 2, choose high voltage converter according to dephosphorization pump lifting speed time and electric machine rotation inertia；

Concrete steps are as it is shown on figure 3, as follows:

Step 201, calculate Rated motor output torque T according to the rated power of motor and rated speed_e；

It is calculated as follows:

$T_e=9550\frac{P_e}{n_e}$

P_eFor the rated power of motor, n_eRated speed for motor；

Step 202, calculate motor angular velocity ω according to the rated speed of motor；

ω=2 π * n_e/60

Step 203, calculate the torque capacity in dephosphorization pump and motor accelerator and the minimum torque in moderating process respectively；

The torque capacity T that in accelerator, dephosphorization pump and motor provide_max:

$T_{max}=J{\frac{d\mathrm{\ω}}{dt}}_{+}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{+}+K\mathrm{\ω}$

J is the rotary inertia sum of dephosphorization pump and motor, T_LFor load torque: T_L=K ω=K*2 π * n_e/ 60；The torque of K representation unit radian, unit is Nm/rad；Utilize load torque T_LConsider the state running maximum (top) speed, calculate K value, as the units of torque constant of subsequent calculations acceleration and deceleration process.

The minimum torque T that in moderating process, dephosphorization pump and motor provide_min:

$T_{\min }=J{\frac{d\mathrm{\ω}}{dt}}_{-}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{-}+K\mathrm{\ω}$

Step 204, ratio according to torque capacity with Rated motor torque, and minimum torque chooses high voltage converter；

By calculating, the ratio according to torque capacity in accelerator with Rated motor torqueValue, choose satisfactory high voltage converter, calculate the minimum torque T of the high voltage converter chosen simultaneously_minMeet not for negative torque；

Detailed process is as follows:

Judge the ratio of torque capacity and Rated motor torqueWhether less than high voltage converter self overload magnification, if it is, illustrate that torque capacity is within frequency conversion system overload capacity scope, conformance with standard chosen by converter, can mate with accumulator, meets dephosphorization output requirement, jointly completes dephosphorization task.Otherwise converter can not complete speed-raising process at accelerating sections, after dephosphorization starts, it is impossible to jointly supplies water for dephosphorization point with accumulator, dephosphorization flow and pressure is caused to be unsatisfactory for process conditions, whole dephosphorization process cannot be completed, it is necessary to return step 203, recalculate and choose high voltage converter.

The minimum torque T provided in moderating process is provided simultaneously_minWhether it is negative torque, if it is, illustrate that the standard of not meeting chosen by converter, energy feedback phenomenon can occur in running, influential system runs, and will recalculate and choose, otherwise, minimum torque is not for bearing torque, and conformance with standard chosen by converter, does not have energy feedback phenomenon.

Step 3, by accumulator, high voltage converter, dephosphorization pump and motor are attached coupling；

As shown in Figure 6, particularly as follows: host computer connects PLC, PLC connects high voltage converter by serial gateway, high voltage converter connects high pressure dephosphorization motor, and high pressure dephosphorization motor connects high pressure dephosphorization pump, and high pressure dephosphorization pump connects accumulator and dephosphorization pipeline simultaneously；High voltage converter and accumulator coherent signal all enter PLC system, high voltage converter the high-voltage motor controlled drives dephosphorization pump and accumulator jointly to complete dephosphorization.

Step 4, the dephosphorization pump that have matched accumulator and high voltage converter is put into production use, it is achieved energy-conservation；

As shown in Figure 4, concretely comprise the following steps:

Step 401, rolling the dephosphorization cycle in, first dephosphorization pump high-speed cruising is that accumulator carries out moisturizing；

Step 402, judging whether run into dephosphorization point in moisturizing process, if run into, entering step 403, otherwise, dephosphorization pump keeps high-speed cruising, for accumulator moisturizing, enters step 405；

Step 403, determining whether that the dephosphorization flow of dephosphorization point is whether more than the flow of dephosphorization pump, if it is, accumulator and dephosphorization pump carry out dephosphorization for overlapping dephosphorization point simultaneously, otherwise, dephosphorization pump is individually for dephosphorization point dephosphorization；

Step 404, complete the dephosphorization of each dephosphorization point after, dephosphorization pump keeps high-speed cruising, is accumulator moisturizing in dephosphorization gap；

Step 405, when accumulator liquid level reaches upper work liquid level or pressure reaches the upper limit, liquid level detection device output signal to PLC, PLC control high voltage converter make dephosphorization pump fall-back；

While step 406, dephosphorization pump keep low cruise, accumulator is individually for dephosphorization point and carries out dephosphorization；

Step 407 is until accumulator liquid level reaches lower work liquid-level pressure when reaching lower limit, and liquid level detection device outputs signal to PLC, PLC and controls high voltage converter, and high voltage converter controls dephosphorization pump fall forward, for accumulator moisturizing, enters the next dephosphorization cycle.

Concrete operations are: in dephosphorization gap, the rotating speed of high pressure dephosphorization pump is regulated, when accumulator liquid level reaches upper work liquid level or pressure reaches the upper limit, it is not necessary to descaling pump supplies water according to accumulator liquid level or pressure, liquid level detection device outputs signal to high voltage converter, controls dephosphorization pump fall-back；When accumulator liquid level reach lower work liquid-level pressure reach lower limit time, liquid level detection device outputs signal to high voltage converter, high voltage converter controls dephosphorization pump fall forward, for accumulator moisturizing, it is ensured that jointly complete the next dephosphorization cycle with accumulator after completing moisturizing process or raising speed before the next dephosphorization cycle starts.

The low cruise Time Calculation formula of dephosphorization pump is: m-pump speed up time-pump deceleration time during m-water supplying pump during the rolling cycle；

The energy-saving run time is: low cruise time+(pump speed up time+pump deceleration time)/2；

According to formula: W power frequency=voltage * running current * 1.732* power factor * runs the time, calculate power frequency year power consumption；According to formula W frequency conversion (considering high low cruise accounting)=voltage * rated current * 1.732* speed ratio³* power factor * energy-saving run time/converter efficiency calculation frequency conversion year power consumption；Year amount of electricity saving is calculated according to formula W joint=W power frequency W frequency conversion；W saves * unit price of power=energy-conservation expense.

Embodiment:

It transform example from energy high voltage converter (AriVert series) as in conjunction with certain project dephosphorization with Chongqing Water Pump Factory's accumulator system and Beijing gold:

The high voltage converter built adds the whole energy modernization system of accumulator, including automated system, high voltage converter, high-voltage motor, dephosphorization pumping plant, accumulator system and each dephosphorization point.Wherein, high voltage converter and accumulator coherent signal all enter PLC system.

The first step, choose accumulator according to the de-scaling water consumption in the rolling cycle；

As shown in Figure 5, it is determined that the rolling cycle is 134S；The de-scaling time that de-scaling point HSB needs is 13s, 17 seconds, the de-scaling interval of de-scaling point HSB and de-scaling point E1-1；The de-scaling time of de-scaling point E1-1 is 14s, 35 seconds, the interval of de-scaling point E1-1 and de-scaling point E1-3；The de-scaling time of de-scaling point E1-3 is 17s, 38 seconds, the interval of de-scaling point E1-3 and de-scaling point E1-5；

The each dephosphorization o'clock overall de-scaling time within a cycle, T=13+17+14+35+17+38=134S；

The E1-5 in a upper dephosphorization cycle overlaps in this cycle, and the E1-5 de-scaling time is 18S；Although FSB does not complete the dephosphorization of overall 90S within the cycle, only have 59S actual time, but the residue 31S de-scaling time-interleaving in the upper cycle is within this cycle, therefore the de-scaling time in FSB unit period is 59+31=90S；

First, analyze all dephosphorization point theory total water consumptions within a rolling cycle, as shown in table 1:

Table 1

Then, also de-scaling overlap water consumption is calculated, it is judged that dephosphorization pump high speed water supply time section: FSB+E1/3 overlapping time is 17S, dephosphorization flow and the flow less than pump according to the de-scaling point that rolling time chart analysis is overlapping, so time the independent dephosphorization of dephosphorization pump, keep dephosphorization pump operation in low speed segment；FSB+E1/5+HSB overlapping time is 13S, dephosphorization flow and the flow more than dephosphorization pump, so time need dephosphorization pump and the common dephosphorization of accumulator, dephosphorization pump operation is in water supply time section.As shown in table 2；

Table 2

De-scaling point	De-scaling flow and (L/S)	With the flow-rate ratio of pump relatively	Overlapping time	Water consumption L
					FSB+E1/3	66.06	<83.3L/S	17	1123.02
FSB+E1/5+HSB	142.606	>83.3L/S	13	1853.88

Calculate the descaling pump height low cruise time, as shown in table 3:

Table 3

Rolling cycle S	134
		Theoretical de-scaling water consumption L	6128.75
Pump high-speed cruising time S	72.4
		Pump speed up time S	8
Pump deceleration time S	12
		Low cruise time S	134-72.4-8-12=41.6
Energy-saving run time S	41.6+ (8+12)/2=51.6

According to rolling line high-pressure water descaling technique, except finish rolling FSB de-scaling point, the time of all the other rolling line de-scalings is short, and accumulator, interval are different in size, comparatively scattered, in order to reduce energy consumption, extends the low cruise time of dephosphorization pump, adopts accumulator to supply water scattered de-scaling.Transporting upper consideration steady, energy-conservation from system, accumulator is the bigger the better, but investment strengthens, and the size therefore rationally selecting accumulator is particularly significant.In order to effectively energy-conservation, extend the low cruise time of descaling pump as far as possible, from upper calculating, within a rolling cycle, the descaling pump maximum low cruise time is 41.6S, and the maximum water consumption of de-scaling water consumption when FSB+E1/5+HSB overlap is maximum, too fast in order to prevent energy storage pressure from declining, now adopt descaling pump and accumulator to supply water, it is ensured that system operates steadily simultaneously.

Optimum operating mode is, furnace rear de-scaling HSB injection valve opens first 10 seconds, descaling pump raising speed is run to 50HZ, descaling pump first mends some water for accumulator, analyze from rolling sequential chart and descaling pump converting operation figure, when HSB injection valve is opened, overlapping de-scaling point FSB+E1/5+HSB 3 runs 13S, 3 flows needed and the flow more than dephosphorization pump, so need descaling pump and accumulator to supply water simultaneously, when dephosphorization point HSB dephosphorization terminates, only FSB+E1-5 2 carries out overlapping dephosphorization, flow less than pump, time is 18-13=5S, namely the water yield own ability of dephosphorization pump now needed can meet, accumulator does not supply water, dephosphorization limit, dephosphorization pump limit is that accumulator supplies water, in dephosphorization gap, dephosphorization pump supplies water for accumulator always, the flow of later stage dephosphorization point E1/1 is less than the flow of pump, accumulator need not supply water.Until after dephosphorization pump high-speed cruising 72.4S, accumulator basically reaches the liquid level upper limit, then liquid level detection device outputs signal to high voltage converter, controls dephosphorization pump reduction of speed, and after reduction of speed 12S, accumulator is fully achieved the liquid level upper limit, and dephosphorization pump keeps low speed 20HZ to run.Accumulator carries out the dephosphorization of 59S for dephosphorization point FSB, dephosphorization point E1/3 de-scaling 17S, when after dephosphorization pump low cruise 41.6S, liquid level in accumulator reaches lower limit, and liquid level detection device outputs signal to high voltage converter, controls dephosphorization pump raising speed, after raising speed 8S, dephosphorization pump keeps high-speed cruising 10 seconds again, mends some water for accumulator, enters the next dephosphorization cycle.

So the water supply of accumulator has, FSB de-scaling 59S, E1/3 de-scaling 17S, FSB+E1/5+HSB 3 is overlapping runs 13S.From table 4 analytical calculation accumulator rate of water make-up:

Table 4

De-scaling point	De-scaling flow (L/S)	The de-scaling time	Total amount L
				FSB de-scaling water consumption	46.26	59	2729.34
E1/3 de-scaling water consumption	19.8	17	336.6
				FSB+E1/5+HSB de-scaling water consumption	142.61	13	1853.93
Accumulator carries out the water consumption of dephosphorization needs			4919.87
				Descaling pump supplies water	83.3	23	1915.9
Accumulator supplies water			3004

In descaling pump water supply 23S time and table 2,13S starts first 10 seconds high-speed cruising time plus HSB dephosphorization overlapping time, and namely the high-speed cruising water supply time of descaling pump is 13+10=23S.

Finally, according to production technology pressure requirements and gas adiabatic equation law, calculate accumulator affects the gas volume of gas exchange under stress in limited time for the resistance of ducting；By calculating, accumulator removes 90% according to gas volume and obtains accumulator actual demand value, is worth according to the actual requirements, chooses accumulator gas tank and air hydraulic cylinder quantity.

The maximum pressure of initialization system is 20.5MPa, the pressure oscillation of accumulator is 8%, namely minimum pressure is 18.86MPa, the motorised volume 3004L of accumulator, according to ideal gas adiabatic equation law: P*V=C can obtain: P height * V height=P low * V is low, and have V low=V height+motorised volume, by calculating, the accumulator gas volume when 18.86MPa is 32412L, gas exchange is affected for the resistance of ducting, moisturizing ability is value of calculation the 90% of normal accumulator, it is therefore desirable to gas volume is 36013L (32412L ÷ 90%).Accumulator volume is bigger, it is necessary to 2 water pots, and the minimum moisture storage capacity (i.e. safety levels) of each water pot is about 3000L, then the total measurement (volume) of accumulator is 42013L, it is considered to system margin, and accumulator system aggregate demand is about 43m3.

Existing accumulator 18m3, it is therefore desirable to increase the accumulator of 25m3, the conventional volume according to accumulator, and take into full account that rolling line rolls the demand of different steel grade, newly increase the accumulator of 4 8m3,1 air hydraulic cylinder, 3 gas tanks.

Step 2, according to accelerating and deceleration time and electric machine rotation inertia choose high voltage converter；

Dephosphorization pump needs to complete band load acceleration and deceleration at short notice, as shown in Figure 4, it is necessary to completes 8S and accelerates and 12S deceleration (velocity interval 20Hz-50Hz).

Need to require converter is carried out type selecting according to this technology.

Device parameter:

First, converter output torque is T, and load torque is T_LAccording to, it is known that blower-pump load curve is 1 time of frequency, 1.7 times or 2 relations, it is considered to the harshest situation 1 curve, i.e. T_L=K ω=K*2 π * n/60, is obtained by the equation of motion:

$T-T_L=J\frac{d\mathrm{\ω}}{dt}$

The rotary inertia sum of dephosphorization pump and motor is J=250kg m², J_Motor=200kg m², it is considered to the rotary inertia of intermediate link and pump, suitably increase；

By the parameter of electric machine: motor rated power P_e=2800KW, Rated motor rotating speed n_e=1494r/min, therefore, Rated motor torqueNumber of pole-pairs N_p=2,

When dephosphorization pump operation is at n_eDuring=1494r/min, corresponding load torque is T_e=17898Nm,

Therefore: T_L=T_e=K*2 π * n_e/ 60, therefore K=114.4Nm/ radian.

Motor angular velocity corresponding for 20Hz is ω₂₀Motor angular velocity corresponding for=62.58 radians/s, 50Hz is ω₅₀=156.45 radians/s,

Therefore: the 8S time from the 20Hz angular acceleration accelerating to 50Hz is:

The 12S time from the 50Hz angular acceleration decelerating to 20Hz is:

The rotary inertia sum J=250kg m of known dephosphorization pump and motor²

Accelerating sections is analyzed:

The torque that required converter provides

Work as ω_eDuring=156.45 radians/s, the torque maximum of required offer is: T_max=20830Nm

Braking section is analyzed:

The torque that required converter provides is

As ω=62.58 radian/s, the torque of required offer is minimum is: T_min=5359Nm is not for bearing torque, thus without energy feedback phenomenon occur.

Consider that converter overload 120% can run 120s, thus, it is supposed that the torque that converter goes out is directly proportional to electric current, then: the ratio of the torque capacity provided in accelerator and Rated motor torque is:

Therefore high voltage frequency conversion system is capable of the acceleration-deceleration change of technological requirement, mates proper with accumulator system.

Step 3, by accumulator, high voltage converter, dephosphorization pump and motor are attached coupling；

Particularly as follows: high voltage converter connects motor, motor connects dephosphorization pump, and dephosphorization pump connects accumulator and dephosphorization pipeline simultaneously；High-voltage motor selected by described motor；High voltage converter and accumulator coherent signal all enter PLC system, high voltage converter the high-voltage motor controlled drives dephosphorization pump and accumulator jointly to complete dephosphorization.

Specifically used environment is: by the accumulator air hydraulic cylinder chosen and gas tank, and air compressor machine, lowest liquid level valve, outlet gate valve, maintenance air lock valve, blowoff valve etc. are connected accordingly, newly-increased accumulator system is connected with main line, and original pump group injection valve, high-low pressure pipeline are constant.

Lubricating system is transformed: lubricating system includes maintenance mechanical oil pump and electric oil pump, after changing frequency conversion into, according to practical situation calculating machine oil pump because acceptor's motor speed changes, if can cause for shortage of oil, it is impossible to meet service requirement, take the circumstances into consideration to increase electric oil pump.In order to anti-locking system has a power failure suddenly, it is therefore desirable to increase corresponding high-order self-sealing fuel tank.

Low-voltage electrical is transformed: low-pressure section mainly increases grease pump, automatic valve, instrument control, controls the amendment of system program, increases part PLC and controls module, and major control cabinet and equipment fully reuse.

High-voltage electrical apparatus is transformed: high pressure transformation part increases high voltage converter, connects control chain, in order to control dephosphorization pump motor, reaches the purpose of frequency control.

Due to the relation that dephosphorization revolution speed is directly proportional to the flow of pump, the relation that revolution speed becomes with the pressure of pump square, the power that revolution speed and pump consume is three cubed relation, therefore, when system does not need descaling pump water supply, by reducing the rotating speed of descaling pump, it is possible to be greatly reduced the shaft power of descaling pump, to reach the purpose of energy saving of system.

From dephosphorization pump water-horse power computing formula it can be seen that

The water-horse power Ne=pump pressure H of dephosphorization pump × flow Q ÷ 3.67 ÷ efficiency of pump

Wherein: the water-horse power unit of pump is kW, pump pressure unit is MPa, and flux unit is m3/h

Before transformation, descaling system pump group is in high-speed cruising state all the time, rolling line not de-scaling and rolling line roll change or rolling line fault light maintenance time (not only other downtime) de-scaling point without water under high pressure but also can not termination of pumping time, former pump can only run at high speed lower-capacity point, pump discharge is only small, pump pressure is high, minimum flow valve is opened, and power of motor is about specified 50%-60%, and energy consumption is equally very big.

Step 4, the dephosphorization pump that have matched accumulator and high voltage converter is put into production use, it is achieved energy-conservation；

Concrete operations are: in dephosphorization gap, high-voltage frequency conversion and speed-adjusting controls dephosphorization pump rotary speed, the rotating speed of high pressure dephosphorization pump is regulated according to accumulator liquid level or pressure, when accumulator liquid level reaches upper work liquid level or pressure reaches the upper limit, need not supplying water by descaling pump, high voltage converter controls dephosphorization pump fall-back；When accumulator liquid level reach lower work liquid-level pressure reach lower limit time, high voltage converter controls dephosphorization pump fall forward, for accumulator moisturizing, it is ensured that jointly complete with accumulator the next dephosphorization cycle after completing moisturizing process or raising speed before the next dephosphorization cycle starts.

Frequency control energy-conservation purpose in reaching three in hot rolling high-pressure water descaling system:

In 1 operation of rolling energy-conservation

In the operation of rolling, after accumulator fills water, examine signal by heat and feed back to PLC, when detection de-scaling point is without water under high pressure, there is certain intermittent time centre (namely in rolling sequential chart, dephosphorization interval time on rolling line), at this moment the rotating speed of pump can be reduced, making pump at low cruise, when heat detects that product is about to arrive when dephosphorization point needs de-scaling or the water of accumulator is inadequate, pump starts raising speed, to accumulator moisturizing, supply water to rolling line simultaneously, more long in the time of low cruise, energy-conservation more big.

It is energy-conservation that 2 pumps when utilizing roll change, maintenance reduce motor speed when can not stop

Be out of order the light maintenance time (i.e. other downtime) in rolling line roll change or rolling line, each half an hour or 1 hours, de-scaling point without water under high pressure, again can not termination of pumping time, at this moment converter reduces revolution speed, energy-saving run.By relevant data statistics, the annual roll change of rolling line, size repair time were accumulated up to 900-1000 hour, and the energy saving space is huge.

3 reach energy-conservation purpose by rolling the steel grade change de-scaling pressure of different cultivars

During system initial design, it is all by the steel grade design pressure being most difficult to de-scaling, carrys out the configuration of design selection system equipment by most fast pace, when such different cultivars steel still uses same pressure flow pattern, will result in great waste.Owing to rolling line rolling is of a great variety, diversification of varieties, high-pressure water descaling system according to the difference of rolling kind, can control flow and the pressure of high-pressure pump, to reach de-scaling purpose targetedly by high-pressure frequency-conversion.

When rolling variety steel de-scaling pressure requirements and being not as high, when some steel grades are likely to 16-18MPa, de-scaling is just satisfied require that, some steel grades need again higher pressure, is at this moment just very easy to by frequency control realize, pressure reduces 1MPa, and power of motor will drop a lot.

Single employing high-pressure frequency-conversion mode controls speed governing, owing to rolling rhythm interval is shorter, and the situation of dephosphorization while of multiple spot often occurs, and high voltage converter deceleration time is relatively short, and energy-saving effect is had a significant impact.The present invention controls dephosphorization pump lifting speed through high voltage converter, reaches stability contorting output pressure, it is ensured that output flow, and reaches energy-conservation effect, and this kind of reducing energy consumption pattern is better than traditional single increase high voltage converter mode.

Claims (3)

1. the energy-conserving reconstruction method based on the hot rolling high-pressure water descaling system of accumulator and high voltage converter, it is characterised in that specifically comprise the following steps that

Step one, choose accumulator according to the de-scaling water consumption in the rolling cycle；

Step 2, choose high voltage converter according to the lifting speed time of dephosphorization pump and the rotary inertia of motor；

Step 3, by accumulator, high voltage converter, dephosphorization pump and motor are attached coupling；

Particularly as follows: host computer connects PLC, PLC connects high voltage converter by serial gateway, high voltage converter connects motor, and motor connects dephosphorization pump, and dephosphorization pump connects accumulator and dephosphorization pipeline simultaneously；High voltage converter and accumulator coherent signal all enter PLC system, high voltage converter control motor and drive dephosphorization pump and accumulator jointly to complete dephosphorization；

Step 4, the dephosphorization pump that have matched accumulator and high voltage converter is put into production use, it is achieved energy-conservation；

Concretely comprise the following steps:

Step 401, rolling the dephosphorization cycle in, first dephosphorization pump high-speed cruising is that accumulator carries out moisturizing；

Step 402, judging whether run into dephosphorization point in moisturizing process, if run into, entering step 403, otherwise, dephosphorization pump keeps high-speed cruising, for accumulator moisturizing, enters step 405；

Step 403, determining whether that the dephosphorization flow of dephosphorization point is whether more than the flow of dephosphorization pump, if it is, accumulator and dephosphorization pump carry out dephosphorization for overlapping dephosphorization point simultaneously, otherwise, dephosphorization pump is individually for dephosphorization point dephosphorization；

Step 404, complete the dephosphorization of each dephosphorization point after, dephosphorization pump keeps high-speed cruising, is accumulator moisturizing in dephosphorization gap；

Step 405, when accumulator liquid level reaches upper work liquid level or pressure reaches the upper limit, liquid level detection device output signal to PLC, PLC control high voltage converter make dephosphorization pump fall-back；

While step 406, dephosphorization pump keep low cruise, accumulator is individually for dephosphorization point and carries out dephosphorization；

Step 407 is until when accumulator liquid level reaches lower work liquid level or pressure reaches lower limit, and liquid level detection device outputs signal to PLC, PLC, and to control high voltage converter be dephosphorization pump fall forward, for accumulator moisturizing, enters the next dephosphorization cycle.

2. the energy-conserving reconstruction method of a kind of hot rolling high-pressure water descaling system based on accumulator and high voltage converter as claimed in claim 1, it is characterised in that described step one particularly as follows:

Step 101, according to rolling time-scale determine one rolling the dephosphorization cycle；

The rolling dephosphorization cycle includes time and the dephosphorization intermittent time of each dephosphorization point；

Step 102, determine the dephosphorization flow of each dephosphorization point in the whole rolling dephosphorization cycle, and calculate theoretical total water consumption；

For certain line, according to the dephosphorization flow of each dephosphorization point and de-scaling time, calculate the water consumption of each dephosphorization point；Thus the theoretical total water consumption calculated in the rolling dephosphorization cycle；

Step 103, determine de-scaling point overlapping in the rolling dephosphorization cycle, and calculate the water consumption of each overlapping de-scaling point；

The water consumption of each overlapping de-scaling point is: the flow of overlapping dephosphorization point and be multiplied by the overlapping dephosphorization time；

Step 104, judge the de-scaling flow of each overlapping dephosphorization point and whether more than the flow of dephosphorization pump, if it is, dephosphorization pump and the common dephosphorization of accumulator, the otherwise independent dephosphorization of dephosphorization pump；

Step 105, the dephosphorization flow rate calculation motorised volume of accumulator within a rolling dephosphorization cycle provided according to accumulator；

The motorised volume of accumulator includes the liquid level of accumulator and reaches the output of individually dephosphorization after the upper limit, and accumulator participates in the output of common dephosphorization；

Step 106, according to the motorised volume of accumulator and gas adiabatic equation law, calculate accumulator affects the gas volume of gas exchange under stress in limited time for the resistance of ducting；

Ideal gas adiabatic equation law: P*V=C

The wherein volume of P to be the pressure of ideal gas, V be ideal gas；C is constant；

Step 107, accumulator remove 90% according to gas volume and obtain accumulator actual demand value, are worth according to the actual requirements, choose accumulator gas tank and air hydraulic cylinder quantity.

3. the energy-conserving reconstruction method of a kind of hot rolling high-pressure water descaling system based on accumulator and high voltage converter as claimed in claim 1, it is characterised in that described step 2 particularly as follows:

Step 201, calculate Rated motor output torque T according to the rated power of motor and rated speed_e；

It is calculated as follows:

$T_e=9550\frac{P_e}{n_e}$

P_eFor the rated power of motor, n_eRated speed for motor；

Step 202, calculate motor angular velocity ω according to the rated speed of motor；

ω=2 π * n_e/60

Step 203, calculate the torque capacity in dephosphorization pump and motor accelerator and the minimum torque in moderating process respectively；

The required torque capacity T provided of converter in accelerator_max:

$T_{max}=J{\frac{d\mathrm{\ω}}{dt}}_{+}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{+}+K\mathrm{\ω}$

J is the rotary inertia sum of dephosphorization pump and motor, T_LFor load torque: T_L=K ω=K*2 π * n_e/ 60；The torque of K representation unit radian；

The required minimum torque T provided of converter in moderating process_min:

$T_{\min }=J{\frac{d\mathrm{\ω}}{dt}}_{-}+T_L=J{\frac{d\mathrm{\ω}}{dt}}_{-}+K\mathrm{\ω}$

Step 204, ratio according to torque capacity with Rated motor torque, and minimum torque chooses high voltage converter；

By calculating, the ratio according to torque capacity in accelerator with Rated motor torqueValue, choose satisfactory high voltage converter, calculate the minimum torque T of the high voltage converter chosen simultaneously_minMeet not for negative torque.