A genset for cement plant duty has to start a raw mill motor in dust and heat and hold the load through a kiln stop. Compare the step capability, the filtration and the cooling against the load list before you accept an offer. Tesla Power sizes the set; send it to the technical desk and we confirm it.
- Ask for the largest motor start rather than the total connected load.
- Check the air filtration against the dust the plant actually makes.
- Look at the cooling, because a cement plant runs hot all year.
- Ask what the set has to carry while the kiln is stopped.
What does a genset for cement plant duty have to do?
It has to start the largest motor on the plant, hold the load while the kiln cools, and keep running in an atmosphere that coats every surface in dust. The load is not the hard part on a cement plant and the start is, because a mill motor draws several times its running current for a few seconds, and the alternator has to absorb that without the voltage collapsing.
The set also has to carry the auxiliary load during a kiln stop, when the fans and the conveyors keep running while the kiln cools over many hours. That is a long steady load at a moderate figure rather than a short heavy one. Tesla Power sizes the alternator for the start and the fuel tank for the cooling period, because the two requirements pull in different directions, and the tank is the cheaper of the two to oversize.
Which load pattern matters?
A cement plant runs at a steady base load with a few large starts a day, and the base load is what the fuel figure comes from. The starts decide the alternator and the base decides the tank. A set quoted on the total connected load is a set that is oversized for both and it runs at a light load, which fouls the engine over a season.
A 1,000kVA set at 0.8 pf gives 800kW: 1,000kVA x 0.8 = 800kW, and a raw mill motor of 400kW started direct on line can pull more than that on its own for a moment. Ask for the motor list with the starting method, because a soft starter changes the answer. Tesla Power Equipment checks the list against the alternator before quoting a frame, and a soft starter is often cheaper than the next frame up.
| Item | Typical figure | Note |
|---|---|---|
| Site temperature | 45 C in summer | Derate from 40 C upwards |
| Derate | About 2% per degree | Ask for the curve, not the rating |
| Air filter | Two stage with a pre-cleaner | Changed on hours, not months |
| Hold load | Fans and conveyors | Sets the tank size |
What does the dust do to the set?
Cement dust is alkaline and it sets when it gets wet, so a filter that is merely dusty becomes a filter that is solid after a rain shower. A set in a cement plant needs a two stage filter with a pre-cleaner and a drain, and it needs the filter changed on hours rather than on a calendar. Ask for the filter class and the change interval in hours rather than in months. The pre-cleaner takes the coarse dust and the element takes the rest.
Dust also settles on the radiator and closes the fins, which raises the coolant temperature without any change in load. A radiator that is cleaned with compressed air from the fan side recovers most of the loss. Ask for the cleaning method in the maintenance schedule. A set on a cement site that is cleaned on load is a set that is cleaned properly, and the interval on a cement site is often 250 h. Tesla Power writes that figure into the schedule.
How is the set cooled in a hot plant?
A cement plant yard reaches 45 C in summer and the set sits beside a kiln that radiates heat, so the ambient figure in the rating is optimistic. A set rated at 40 C loses about 2% of its output for every degree above that, and a derated set is a set that trips on the mill start. Ask for the derate curve rather than the catalogue rating, because the catalogue figure is taken at 40 C.
The enclosure makes the difference, because a canopy that recirculates its own hot air adds degrees that the site did not have. An inlet low and an outlet high, with the two separated, is the arrangement that works in a hot yard. Ask for the louvre positions on the drawing. Yangzhou Tesla Power derates the frame for the site temperature rather than quoting the standard figure, and the difference shows on a July afternoon.
What fuel suits a cement plant?
Diesel is the usual fuel for a standby set and heavy fuel oil is used on the large prime power units, and the two need different engines and different tanks. A set that runs for hours every week on diesel is a set that pays for a larger tank. Ask for the burn at the hold load rather than at rating, because the hold load is what the tank is sized for, and the hold load is lower than most buyers assume.
A cement plant also has the option of running the set on the fuel the kiln uses, and that option belongs to a prime power unit rather than to a standby one. A standby set converted to heavy fuel needs a heater and a separator, which is a different project. Ask which duty the set is bought for before the fuel is discussed, since the two duties lead to different engines.
How is the set maintained on a cement site?
The maintenance interval on a cement site is set by the dust rather than by the hours, so the air filter and the radiator cleaning come before the oil change. A set that follows a standard schedule on a cement site blocks its filter between services. Ask for a schedule with the filter and the radiator on a separate line, with the hours for each item.
The fuel filter is the second item that suffers, because dust enters the tank through the breather on every refuel. A breather with a filter and a water trap at the tank low point keeps the fuel clean. Ask for both on the drawing. A set that stops on a blocked filter during a kiln stop is a set that costs a day of production. Tesla Power fits the trap as standard on a cement build. A spare filter set on the shelf is the cheapest insurance on a cement site.
What does the offer need to state?
The offer should give the rating at the site temperature, the step capability, the filter class, the louvre arrangement, the tank size and the derate curve. Six items on one line let a buyer check the set against the motor list and the yard without reading a drawing. Ask for the step capability as a percentage of the rating rather than as a phrase.
The wording on the offer matters too. Chinese genset for cement suppliers often quote a rating at 40 C with no derate, and a genset for cement plant manufacturers page can show a filter the factory fits only on request. Chinese genset for cement factories often quote the filter as a single element with no pre-cleaner. Ask for genset for a raw mill, genset in a quarry and genset for the kiln as three separate cases. Tesla Power prints the six items on the plant drawing.
What does the handover file record?
The file carries the rating at the site temperature, the step capability, the filter class, the tank size and the derate curve. One page covers the set when those five items sit under the serial number. Add the conformity assessment for the plant when the set is part of a permit package and the emission figure is written into the consent.
Hand the page to the maintenance planner rather than to the buyer who placed the order. the Yangzhou factory describes the bay where the filter is fitted, the commissioning notes lists the frames with a two stage filter, the build range explains how the derate is calculated, the 500kVA silent set with ATS changeover shows the export build for this rating, the ISO 8528-1 duty definitions sets the rating basis the derate comes from, and the NFPA 110 maintenance routine covers the emission rule behind the consent.
Frequently asked questions about cement plant generator sets
Size for the largest motor start and check the result against the base load, because a set sized for the start runs light for the rest of the day. A light load fouls the engine over a year. Ask for the motor list with the starting method.
It needs a two stage filter with a pre-cleaner and a drain, because cement dust sets when it gets wet. A standard filter blocks between services. Ask for the filter class and the change interval in hours.
A prime power unit can and a standby set needs a heater and a separator before it can. That is a different project rather than an option. Ask which duty the set is bought for before the fuel is chosen.
The alternator is too small for the starting current or the derate at the site temperature has not been applied. Both are visible in the offer. Ask for the step capability as a percentage of the rating at the site temperature.
Monthly on a cement site and weekly during a dusty season, with compressed air from the fan side. A radiator cleaned from the outside pushes dust further in. Ask for the method in the schedule rather than the interval alone.
It carries the fans and the conveyors while the kiln cools, which is a long steady load rather than a heavy one. It sets the tank size. Tesla Power writes the hold load and the hours on the same line so the tank is sized once.