ABB drives in cement Medium voltage drives for reduced energy consumption and optimized process control

Transcription

1 ABB drives in cement Medium votage drives for reduced energy consumption and optimized process contro

2 2 ABB drives in cement

3 Increasing cement quaity and reducing operating costs With product quaity demands and production costs rising, yet cement prices faing, the cement industry needs to use the most efficient technoogies to safeguard its future. To be profitabe, cement producers need to: Reduce energy consumption per ton of produced cement Increase avaiabiity of equipment and reduce shutdown period Reduce maintenance costs Achieving high eves of efficiency and avaiabiity wi increase production output, improve product quaity, ower energy costs and CO 2 emissions. Energy-efficient processes in harsh conditions demand efficient and reiabe process equipment Equipment in most cement industry processes are exposed to extreme working conditions such as dust and high temperature variations. Such conditions put a high demand on the process equipment. To ensure consistent high quaity cement, the process equipment has to operate reiaby under these conditions. Variabe speed drives VSDs provide optimized process contro and save energy. ABB has been suppying variabe speed drives for over 30 years. Today, VSDs are used in a wide range of appications in the cement industry, such as: Induced draft (ID) / forced draft (FD) fans Baghouse fans Preheater tower fans Kin gas fans Cinker cooer exhaust fans Separator fans Raw mis Cement mis Conveyors Rotary kins Coa mis Furthermore, cement production is very energy intensive. Much of the energy used is consumed by eectric motors. Sti today, many of these motors are constanty running at fu speed regardess of actua output requirements, wasting a tremendous amount of energy. In many appications, energy use can be cut by up to 30 percent by controing motors with variabe speed drives (VSDs). ABB drives in cement 3

4 Variabe speed drives for cement appications Various processes and appications benefit from using variabe speed drives. Quarry and conveying Conveyors Crushers 4 ABB drives in cement Raw mi and separation Fans Fiters Mis

5 Kin and cinker cooing Rotary kin Fans Conveyors Fiters Fue handing Mis Conveyors Fans Fiters Cement grinding Roer presses Mis Fiters ABB drives in cement 5

6 Benefits of variabe speed drives Controing processes with variabe speed drives has a direct impact on a company s operating costs. Fixed versus variabe speed contro The most common fow contro method is by means of a fixed speed motor where the fow is adjusted by a mechanica device. This method can be compared to adjusting the speed of a car by braking whie keeping the foot on the gas peda. This technique does not ony waste a tremendous amount of energy, it aso wears out the equipment. Benefits of variabe speed drives Lower energy consumption and CO 2 emissions Minimized mechanica wear of equipment Higher process quaity and efficiency Increased productivity and throughput Less investment in eectrica network compensation devices, such as fiters With eectric variabe speed drives, changing the fow is simpy achieved by adjusting the speed and/or torque of the motor, which can be compared to reducing the speed by taking the foot off the gas peda. The equipment is operated at the BEP (Best Efficiency Point) under a operating conditions. Eectric variabe speed drives are the most efficient contro method saving energy, decreasing CO 2 emissions and minimizing tota operating costs. Variabe speed drives repace mechanica contro devices such as hydrauic coupings, vaves, fan inet vanes and dampers which are often used throughout the cement making process. I Fig. 1: Power consumption for various fan contro methods 6 ABB drives in cement

7 Energy savings and reduced emissions The energy consumption of most motor-driven appications can be reduced with variabe speed drives. Fans, for exampe, typicay run at partia oad. Huge energy savings can be achieved by controing their speed with VSDs. The power required to run a fan is roughy proportiona to the cube of the speed, ie a sma reduction in speed can make a big reduction in the energy consumption. A fan running at haf speed consumes as itte as one eighth of the energy compared to one running at fu speed. By empoying VSDs on fans instead of dampers and vanes, the energy bi can be reduced by as much as 60 percent. Consequenty, eectric variabe speed drives aso hep to reduce CO 2 emissions. Soft starting eiminates high starting currents and votage dips which can cause process trips. By soft starting, maintenance costs wi be reduced and the ifetime of the equipment extended. Reduced maintenance costs and onger ifetime of equipment VSDs aso act as soft starters, reducing the stress on network, motors and process equipment. During the starting process, the VSD progressivey increases the motor speed and smoothy acceerates the oad to its required speed. Fig. 2: Motor current for various starting methods ABB drives in cement 7

8 Appications Fans Energy savings and improved process contro The performance of centrifuga fans is controed by a set of rues known as the affinity aws, which state that: 1. Fow is proportiona to speed 2. Pressure is proportiona to the square of the speed 3. Power is proportiona to the cube of the speed. The diagram shows a typica fan characteristic which is a function of voume fow and pressure. Aso shown is a typica system characteristic. The operating point of the system is at the intersection of these two curves. If the required voume of air is deviating from this point, the fan or system characteristic needs to be changed. 2 1 Traditionay, the most common way of changing the operating point is by using a damper which aters the system characteristic (operating point moves from position 1 to 2, see Fig. 3) increasing the system osses. However, increasing or decreasing the fan speed with a variabe speed drive wi change the fan characteristic itsef (point of operation moves from position 1 to 3, see Fig. 3) without adding additiona osses. The energy consumption can be reduced significanty because ower pressure is needed for the same air fow. 3 Fig. 3: Typica fan characteristic showing operating point Drives in action Jura Cement, Switzerand s second argest cement producer, repaced a 25-year od cascade converter with a VSD from ABB. The ACS 2000 drive system, rated at 550 kw, contros the cinker cooer exhaust fan of Jura Cement s cement pant in Widegg, Switzerand. The repacement resuted in the foowing benefits: Higher avaiabiity Reduced maintenance costs Some 20 percent ower energy consumption Wide range of speed contro from 0 to 1,000 rpm The cinker cooer exhaust fan pays a critica roe in the cement making process. Raw mix enters the kin and is heated to 1,450 degrees Cesius where it is transformed to cinker. Upon exiting the kin, the cinker is cooed to 100 degrees Cesius by the cinker cooer fans which bow cooing air through the cinker. By controing the cinker cooer exhaust fan, the drive keeps the pressure in the kin hood constant. It does this by reguating the fan speed that draws cod air through the cinker cooer in reation to the hot air that is being drawn through the kin. Accurate energy input is critica to the quaity of cement insufficient heat wi resut in poory burned ow quaity cinker whereas excess heat might damage the kin she. Cinker cooer exhaust fan motor at Jura Cement 8 ABB drives in cement

9 Appications Mis In cement production, mis are process critica. Reiabe and precise contro has a high impact on production throughput and operating costs. Controing them with variabe speed drives resuts in the foowing benefits. Optimized pant production By controing a mi with a VSD, the speed of the mi is tuned for optima grinding and maximum throughput, resuting in a more efficient use of the grinding power. If up and downstream processes require a ower grinding throughput, the mi can be operated at partia oad without having to stop the process. VSDs can adjust the speed according to charge voume. Less wear and higher reiabiity Grinding raw materia and cinker causes considerabe wear to the grinding mi. Starting the mi direct-on-ine stresses the mi and the gearbox, increasing the risk of gearbox faiure and shortens the ifetime of mechanica equipment. VSDs hep optimize the mi speed to match the materia fow, thus minimizing the wear of the grinding mi. Energy savings Grinding mis can consume more than 60 percent of the pant s tota eectrica energy. Controing them with VSDs resuts in significant energy savings. Smooth ramp up Torque pusations and peak torques, generated by mis during the starting phase, creates high stresses on network and mechanica equipment. VSDs provide a smooth ramp up of the mi. They deiver high starting torque for the current drawn from the power pant system and have a programmed upper imit to reduce peak current during the start of the mi. The ow starting currents and high starting torque enabe a smooth start-up of the mi, even when fuy oaded. ABB drives in cement 9

10 Appications Conveyors Extended ifetime and increased avaiabiity Conveyors are found in amost every cement pant. The environment is demanding and there is aways a risk of damaging the bet by overstretching, sipping or breaking. To reduce operationa costs, it is important to extend the bet ifetime and avaiabiity. Variabe speed drives provide accurate torque and speed contro of conveyors. This reduces the stress on mechanica equipment such as gearboxes, puey and bets, especiay during start-up and stopping, but aso during operation and maintenance. With the use of VSDs it is possibe to contro the speed of the conveyors to match the production capacity and as such reduce wear and save energy. For maintenance inspection, bet changes or repairs or avoidance of ice buid-up it is possibe to run the conveyor bet at sow speed. Accurate and fast oad sharing ABB medium votage drives provide an accurate and fast oad sharing between severa drives. This is usefu for conveyor appications, where two or more motors operate on the same conveyor bet, making sure a motors are oaded as needed. The converter contro provides a window speed imitation to prevent bet sippage. Power factor compensation With ABB medium votage drives the power factor is greater than There is no need for additiona power factor compensation and there are ess osses on the eectrica network. Aso, the eectrica network is not exposed to high inrush currents when the conveyors are started. Regenerative braking of downhi conveyors saves energy To avoid unnecessary conveyor wear, downhi conveyors require continuous braking, which varies depending on the raw materia transported. VSDs provide precise speed and torque contro which is required for the continuous braking need demanded by downhi conveyors. With VSDs, the braking energy can be fed back into the pant s eectrica network, thereby generating energy. 10 ABB drives in cement

11 Appications Kins Variabe speed drives are used to contro the rotationa speed of cement kins. As the speed of materia fow through the kin is proportiona to rotation speed, a VSD is required to contro it. In addition to speed, VSDs provide controed torque. Specia requirements of kin drives High reiabiity. As cement making is a continuous process the kin needs to operate 24 hours a day. As each kin stop can cost severa thousand doars per hour, maximizing uptime is paramount. A wide range of speed contro. During norma operation the rotary kin is to be driven with the most suitabe speed. This is decided by the condition of the materia combinations and the combustion even if a oad variation occurred. High contro accuracy is required for an accurate oad sharing if more than one motor is used. High starting torque. For the nomina starting period the rotary kin must be driven with ow speed unti the temperature becomes sufficienty high. High starting torque A specia design requirement is the starting torque. It is typicay 250 percent of fu oad torque for the first three to five seconds before dropping to around 200 percent and graduay reducing further during the next 15 to 20 seconds at the end of which period the fu speed is attained. This can be seen in figure 4. The physica size of the kin and the weight of its contents mean that its inertia is fairy arge. The eccentricity of the oaded materia inside the kin aso substantiay adds to the required starting torque. Accurate and fast oad sharing To avoid osciations in kins with dua motors, high performance torque accuracy is required. This is achieved with the accurate and fast oad sharing function of ABB s medium votage drives. Fig. 4: Typica starting characteristic for a kin ABB drives in cement 11

12 ABB medium votage drives The heart of a medium votage drive system is the frequency converter. ABB offers the entire range of frequency converters for medium votage appications in the power range from 250 kw to more than 100 MW. ACS 1000 (315 kw 5 MW, up to 4.16 kv) The ACS 1000 is suitabe for retrofit appications and new standard induction motors. Due to its unique output sine fiter, bearing currents and votage refections at the motor are eiminated. The ACS 1000i is a fuy integrated drive incuding input transformer and input contactor. ACS 2000 (250 kw 1.6 MW, kv) The ACS 2000 is suitabe for retrofit appications and new standard induction motors. It can be used without an input isoation transformer, thereby aowing a direct connection to the ine suppy (direct-to-ine), with an integrated transformer, or for connection to an externa input isoation transformer. The ACS 2000 is aso avaiabe for four-quadrant operation for energy regeneration and reactive power compensation. ACS 6000 (3 27 MW, up to 3.3 kv) ABB s ACS 6000 is a moduar drive designed for singe or muti-motor appications for synchronous and induction motors. It can be equipped with an Active Front End which enabes four-quadrant operation for energy regeneration and reactive power compensation. MEGADRIVE-LCI (2 100 MW) ABB s MEGADRIVE-LCI is an optima soution for high votage and high power appications. Standard designs are avaiabe for ratings up to 72 MW; engineered designs for more than 100 MW. The MEGADRIVE-LCI is avaiabe as variabe speed drive or soft starter. ACS 5000 (2 32 MW, kv) The ACS 5000 can be appied to standard industria motors (induction and synchronous). It is idea for appications in the higher power range such as induced and forced draft fans, feed-water and cooing water pumps. The air-cooed ACS 5000 is aso avaiabe with integrated transformer. 12 ABB drives in cement

13 Technoogy highights Reiabiity is the main guiding principe of the research and deveopment activities for medium votage drives. Direct Torque Contro (DTC) The ACS drive contro patform is based on ABB s awardwinning Direct Torque Contro (DTC), resuting in the highest torque and speed performance, as we as owest osses ever achieved in medium votage drives. Contro of the drive is immediate and smooth under a conditions. Power oss ride through Due to its power oss ride through function, the drive system is abe to withstand disturbances of the power suppy. The drive wi continue to operate in an active but non-torque producing mode if the incoming suppy votage is cut off. The drive is active as ong as the motor rotates and generates energy to the drive. It wi resume norma operation immediatey upon return of power suppy. Remote monitoring and diagnostics DriveMonitor TM aows secure rea-time access to the drive. It supports monitoring and diagnostics of ABB drives independent of the impemented contro method, thus enabing the connection of existing instaations. The optiona too consists of a hardware modue, as we as a software ayer that automaticay coects and anayzes seected drive signas and parameters. Long-term monitoring functions deiver important information on equipment status, tasks needed and possibe performance improvements. Diagnostic procedures and trending can cover not ony the converter itsef but other parts of the shaft train as we. Low parts count The fewer the parts the higher the reiabiity. ABB uses high power semiconductor switching devices and a topoogy that minimizes the parts count. Fuseess design ABB medium votage drives are designed to operate safey without fuses which are known to be unreiabe, costy and subject to aging. The fuseess design resuts in ess spare parts and fast re-starting. ABB drives in cement 13

14 Motors and transformers A variabe speed drive system incudes a medium votage converter, motor and transformer. ABB offers the compete variabe speed drive system or assists in seecting components that match the process requirements. ABB s equipment is known for its state-ofthe-art technoogy, high efficiency, reiabiity and wordwide support. Converter motors ABB s converter motors have earned an exceent reputation for performance and reiabiity. ABB s product range incudes induction as we as synchronous motors. Induction motors are the workhorses of industry due to their versatiity, reiabiity and simpicity. In the power range up to 10 MW, a squirre cage induction motor is usuay the first choice. They are avaiabe up to 25 MW. Synchronous motors are typicay considered for higher power ratings (eg above 8 MW to more than 100 MW). In addition to their high power capabiities, synchronous motors offer the benefits of high efficiency and high performance through the utiization of different rotor designs. Converter transformers Converter transformers are especiay designed for operation with variabe speed drives. They adapt the converter to the suppy network and provide a gavanic isoation between drive and suppy network. Converter transformers are avaiabe for neary a ratings. Secondary votages are optimized to match the converter and motor votage. Oi or dry types for indoor or outdoor mounting are avaiabe. Busbar connections can aso be provided. 14 ABB drives in cement

15 Testing, service and support ABB drives are backed by comprehensive service and support, from the customer s initia inquiry throughout the entire ife cyce of the drive system. Testing ABB is committed to ensuring the reiabiity of every drive it deivers. To verify that quaity standards and customer requirements are fuy met, every component of a drive is subjected to thorough testing in ABB s modern test faciities. Routine tests and functiona tests form an integra part of the scope of suppy of ABB s medium votage drives. They are performed in accordance with internationa standards and ABB quaity assurance procedures. Additionay, ABB can perform a combined test with the compete drive system incuding transformer, converter and motor to verify the performance and to ensure a smooth integration into the customer s faciity. Training ABB provides extensive training for its medium votage drives. A range of training programs is offered from basic tutorias to programs taiored to the customer s specific needs. In addition, site personne can be given practica training by experienced speciaists on site. Goba network, oca presence After saes service is an integra part of providing the customer with a reiabe and efficient drive system. The ABB Group of companies operates in more than 100 countries and has a wordwide network of service operations. Instaation and commissioning Proper instaation and commissioning of the equipment, done by quaified and certified commissioning engineers, reduces start-up time, increases safety and reiabiity and decreases ife-cyce costs. Life-cyce management ABB s drive ife-cyce management mode maximizes the vaue of the equipment and maintenance investment by maintaining high avaiabiity, eiminating unpanned repair costs and extending the ifetime of the drive. Life-cyce management incudes: Providing spare parts and expertise throughout the ife cyce Providing efficient product support and maintenance for improved reiabiity Adding functionaity to the initia product Providing a smooth transition to a new technoogy at the end of the ife cyce Services for ABB s medium votage drives Instaation and commissioning Training Remote services Preventive maintenance Customized service agreements Loca support 24 x 365 technica support Spare parts and ogistics network Wordwide service network ABB drives in cement 15