When the mill was stopped and bags allowed to pulse and clean itself and mill was restarted, same trend occurred, blaine started to drop after 4 hours of operation. Is there excess moisture in the Baghouse? The valves wont fire if there is no air in the air header tank. Have the Filter Bags been checked to have proper tension? A combination of 12 and 16 bags seems to work pretty well. Dust collection is transferred back thru mill via closed loop system with degermed corn to dryer then picks up this filterhouse. From reading your blog it looks like I should be looking at leakage causing moisture and bridging.? Upon restart after the cleaning the system appeared to be operation properly, but within a few minutes we noticed the amps dropping from 100 to 65. We are trying to run Fuel Pellets instead of coal in a Stoker Boiler and the filters are blinding over and creating problems in the bag house. Thanks.. You can measure it both before and after if you wantbut usually its best to know the temp before it enters the unit so you can use that information to guide fabric choice among other operating variables. By rotary step, do you mean a rotating arm low/medium pressure reverse air baghouse? When we started operations we were within the 4DP and static pressures for dirty and clean sides have generally been -23 & -27 at the start. Any advice would be appreciated. Has the situation improved since you posted your comment? Maybe send some photos as well. Hi, we are having a bag filter dust collector system in Ash handling plant of coal fired thermal power station. What Kind Of Dust Collector Is Right For Me? Was the airflow to the unit increased recently? This may take sometime. we have a cyclone dust collector on a joy drill rig. Can you suggest me by using your bag filter(PTFE fabric) can this problem be solved. Storing dust in the hopper can lead to filter failure, plugging and other process problems.
Here are some of the common indicators your dust collector is having issues, and how you can troubleshoot them. If you want feel free to email us directly here and we can talk you through the issues in depth.
It could be a number of different things. per temperature or with distance? REgarding your filled bags it could be the holes are too small to notice or it could be a leak in the seam or near the tubesheet thats causing the dust to collect inside. Leakages in the inter connecting ducts, bag filter as well as filter bags, Experiencing high positive pressure at the roller mill house. You do not need to battle with abraded bags for the long term. Keeping your dust collector healthy will prevent unscheduled down time, production loss, or a costly shut-down. Hi, Hello, you may also need to adjust your clean air damper to get more cfms out of your fan. Do I read correct you have the ON time set to 7.2 seconds? I contacted the guys who installed the filter bags and I was told no pre-coating was used. My first guess would be that somehow the baghouse continues to have some kind of airflow through it when its off.
The only real solution for blinded bags is to replace them. If you would like, we can get you pricing on some replacement gasket if you send us a picture with some basic dimensions and a request for how many feet you want. We have bag house at cement plant RM area ,main bag house after we replaced all Fiberglass bags still dust emissions. I have recently switched from methane to natural gas. This is a rotary step baghouse not a pulse jet. While the proceeding information applies to all Baghouse designs, the following covers specific design related problems.
You may also need to look at things like hopper vibrators to break up the dust. IF you have a problem of too much dust coming off the bags when you clean and it overwhelms the discharge, then you should try cleaning the bags more frequently, possibly while they are online (if you do actually have a pulse jet). It sounds like you are getting leaking through your baghouse on a rotary dryer. Is the fan turning in the right direction? Is the inlet duct becoming smaller because the duct diameter is reduced going into the unit or are you saying the product slowly builds up in the duct, blocking it off and making the air pass through a smaller area (and thus increasing in speed) ? Perform colored fluorescent die test to identify, if possible. So as you said, keep the DP as low as possible and keep the cake from forming too muchit gives a place for the moisture to condense and form hard, sticky cake. Please help with any suggestions thanks, Determining where to drill holes and install the probes seems to be the hardest info to find. IT could very well be the problem. We offer our audit services at very reasonable rates and even offer rebates that can potentially make our audits free. With low temps on baghouse we are not getting the moisture out. You can read our articles about DP troubleshooting here:Baghouse Differential Pressure How to Troubleshoot False Readings. The most common variations in Baghouse design regard the cleaning mechanism. I was steadly able to run 350 to 380 tph all summer no problem now hardly able to run 225 to 250 tph . But after tripping ID fan huge dust fall down from bags.and accumulated in bagchambers. With all the problems listed something has definitely changed. If increased, how much?? Our 12 bags will fill up with dust but not the 55 gal Try replacing a number of bags say 10-30 and see if that has any effect. Weve got some baghouse troubles and Im looking for some ideas. Wondering where and how the dust flows through those 2 bags? Have you done a dye leak test on the unit? After replacing bags and vacuuming the clean side, the DP is still achievable but static pressures of -15 & -19. Re-check entire system for changes. Check the solenoids and the controller connections to make sure everything is good.
Done inspection on filter bags, found 2 bags full of dust inside. Are the cleaning pulses at set to the correct duration (0.1 .015 sec)? If correct, the lower pressures indicate that your fan is not pulling as hard since the clean side vacuum is much lower. If ductwork then the product being transferred is too wet at too low of a temperature to start with. I have also check my slam dampner, and exhaust fan blades there all straight up and down. Operating and maintaining an equipment system as complex as an Industrial Dust Collector can be a challenge.
If its settling in the bottom of the duct and building up you could have an issue with product dropout from a air speed within the duct (dropping below the minimum conveying velocity).
Thanks a lot. This is not a problem with clear hoppers. Good points Dustin!
You may also have benefited from PTFE membrane to help with dust release, or the pulse jet settings could have been wrong. instead of using pulsation we are getting high pressure drop across the bagfilters(50-60 mmHg). Is the cleaning cycle set to the proper interval? That might be your best solution. Inspect rubber diaphragms and orsolenoid sealsand replace as needed. After temper process we degerm the corn then dry it down for customer specs. Since starting in September, I have not cleaned the short steel sensing lines. You can try to reduce the moisture content in the processas its really not good practice to send any moisture into your baghouse if you can avoid it.
It could also be that the fuel pellets have a different chemical makeup that are somehow affecting the filters (e.g. Otherwise, you can try making sure that you have everything well above the dew point, from the ductwork, to insulating the baghouse, especially around contact points. I dont see how you would have positive pressure on the clean side, regardless of whether the filters are dirty or not. Heres a few things to try: Any help would be much appreciated.
Rotary step is not a standard term so Im not sure what you are referring to.
It has to do with our scale floor the lower garner is being pressurized and completely wiping out 5th and 6th floor. It sounds like you are having problems with the collection system not being able to keep up with the dust generated. If you cannot reasonably remove the moisture from the process you only choice is to deal with it by maintaining as ideal of conditions as possible in your baghouse. The transporter gets hot so I know it is getting some ash. Ive gone up on my baghouse temp 430F. Many thanks Is the Baghouse the undersized for the application? When ash is filling the hopper to this level the velocity is increasing, trajectory changing, and hitting the bottom of the bags causing holes. Flow 15000 cfm If there is another wrong with it you may want to look into getting a better airlock with a faster discharge rate. Are the Bags leaking from either the clamps, or are from being too porous? If you are using a fan that blows back into the unit this is actually a reverse air dust collector. ON time for the pulse valves should be something like .08 .12 seconds. We have 8 bag filter system but in a particular system facing problem of High DP from last 6 months. There is a heap getting formed in the middle of bottom hopper and it is getting hold up over the screw. IF the dust is passing THROUGH the filters then you likely have massive leaks or you have too small of a baghouse to handle the amount of gas you are trying to pass through it. l work in a tobacco company,in charge of Dustroom the problem l have now that, the production section does not have enough suction for production, how can solve the problem. Most are between 3:1 6:1. Solenoids do go bad overtime so you might have to replace them. If not, that would be the first step. Are the Bags being cleaned at the proper intervals? If our dust collector is working proper, what I feel that we should have only negative pressure. I work at a grain elevator and we have a serious issue. Maintain 80 to 90 psi in header. OUR FILTER BAG HOUSE IS NOT SUCING THE AIR WELL. I would greatly appreciate any help you could offer me. San Diego & Los Angeles Areas Dust Collection System Site Visits, Houston, Texas Dust Collection System Site Visits, Las Vegas, Nevada Dust Collection System Site Visits, Dust Collector Maintenance, Operation & Optimization, https://www.baghouse.com/wp-content/uploads/2018/03/BH-Logo-Alt-01.png. What could be causing my drum to steam and at my discharge chute? Are you getting the proper amount of Air Flow (Cubic Feet per Min) from the Blower?
Are you bleeding air in anywhere along the way thats causing it to drop? Once we know more we can help you with the problem. IF that is so, the first thing you need to do is replace the gaskets around the ports. We had a faux pas in hopper clearing frequency briefly and I had to change a row of bags that had their bottoms abraded. They didnt seem to work well as plugging was a big problem. I am looking forward for a bag filter that will be suitable for my system. If the DP is still high even with new filters its possible the baghouse is undersized. Are any other Baghouse functions affected when Shaking process begins (Fan, or Isolation Dampener, etc)? 3. This is issue I am facing since I have started my plant. See here for more information or give us a call or email. Permeability (M cubed/M squared MIN@13mm W.G.) If you want to get specific help you can email us and we will be glad to recommend an air to cloth ratio for your application. Once your bags are old and blinded they will get plugged up very quickly no matter how light the load since they can no longer be cleaned effectively. Is your Blower (System Fan) powering on and operating properly? Dust is of calcium hypochlorite. if you are running up to 430 degrees at the inlet of the bag house you wont see any condensation across the bags unless your cake is to heavy and your not getting a good pressure drop.
IF you do not provide enough suction then the dust will buildup inside and cause lots of problems. Plant Manager How old are your bags? Normally, increasing airflow to a collector is not really possible without expanding it or installing a new unit. It sounds like normal cleaning, online or off, isnt knocking off enough dust.? Dust get surge out once in a day.
3R5. Air load is 3000 m3/hr with 65 MT of Ash. Mixing bag lengths is not always the best option as it itself messes with the aerodynamics within the unit and causes disruptions within the airflow. Its purpose is to collect plastic bags thru an air lock and deposit them into a bin. If the duct is being closed off by build up of dust you have a different issue. It gets affected drastically. Is the system purged properly after each shutdown? you should check that any diverters, dampers, etc. can used hydrophobic coatings for filters?
Also the filters could be installed incorrectly. I have changed all combustion flights as well. Maybe its connected to another system via ducting that continues to generate draft even when the unit is off? What could be causing this to happen repeatedly in this module? It looks like powder is not getting distributed over the entire screw. Alternatively, you could try installingPTFE membrane filters, which do not require precoating. Product has historically always been damp but this is dripping wet water/flour/dust sludge that cakes lines solid into some sweeps. I have a rotary step bag house i have check all roto steps for proper working condition. Since the dust is added to our process. Our filter house bag is not blasting; it is always piling up dust.
What else can I do or any answers thx. Also, how sure are you of your temp readings on the kiln? Also, its very likely that although you cleaned the bags, they plugged back up very quickly. Check the cleaning system and make sure its operating correctly. Pressure 4bar In turn this will identify the failed valve or solenoid assembly.
Side note. Most fall within 3,500 to 4,500 ft/sec. Note:conveyors are covered. Is cleaning interval at the lowest setting the will allow air manifold pressure to rebuild? Dear Sir We have a high D.P pressure even at low loads any ideals? Is the motor pulling the specified proper amount of Amps? Please advise. This also requires following a strict startup/shutdown procedure to make sure you dont have condensation problems at the beginning or end of a shift.
If too much dust falls off at once (especially with certain sticky dusts that accumulate easily) the dust can bridge across the hopper discharge and the resulting blockage will pile up high into the collector. If yes,is it on inlet or outlet? I have recommended to provide a vacuum line on the top of dust discharge line and to be connect with same dust collector to reduce the spillage of these fine particles.
2. If they are blinding fairly quickly after you change them it may be that other conditions are not optimal and you need to improve system efficiency (many factors impact efficiency). Have all gauges and pressures sensors been checked for accuracy? But is there a way to support this dust system without replacing? If the pleat depth is too short or the pleat count too high the same bridge effect can happen between the pleats on the filters. You also can look into preheating the system to make sure you have everything above the dew point below introducing the airstream to the unit. Loading oats seems to be a factor. They do not make the bags waterproof by any means.
He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. The past few weeks the system has been loosing suction at all locations the farthest point even more so. 3172 N. Rainbow Blvd. Replace fuse or timer. If the product comes out of the Baghouse hopper at a temp higher than the dew point temp then condensation will occur. Plz help.
Can you give any solution for this. I do not see any fluctuations when its in use. system is shutting down and it says chain overload.
More likely than not, the problem is the gaskets (which need to be replaced regularly). If you go to longer pleated filters you need to recalculate the air pressure, but also the blow pipe size, height, hole size, etc. Here at Baghouse.com we pride ourselves on being experts in our field, with decades of experience designing, installing, maintaining and servicing every kind of Dust Collect design available. The also has the effect of improving efficiency and service life on the filters in the baghouse since they then only handle the fines as opposed to all the coarse particles and the fines. I will reply back once I have more detailed information All baghouse filters need to be cleaned regularly to function properly. Done changing 2 new bags. Dominick The dust is not emptying from the hopper faster enough during peak loads. This issue did not happen until 15 years ago from what I have heard but it had gotten so bad. Thanks for mentioning that hoppers can retain too much material and prevent proper operation if they arent cleaned regularly. We havent added or took away from this setup in 3 years. Ive also running my cleaning cycles faster. At very high airflows (when you exceed the recommended airflow for the baghouse) you can actually begin to see dust pulled through the fabric due to the high velocity alone. Learn how your comment data is processed.
document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Thanks for your reply. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Get notifications when we post new content. Can you tell me a little more about the system? Using PTFE membrane bags certainly helps with dust release, but only if they are cleaned using pulse jet, or reverse air. If you would like to discuss this more in depth you can email me directly at info@baghouse.com, or give us a call tomorrow at (702) 848-3990. Our cr288 filterhouse for our fluid bed dryer which dries the degermed corn (indirect heat)has started to condensate and plug apu lines and cause downtime problems daily.
Could it be that the exhaust fan is not exhausting enough air from the baghouse?
We plan on placing a Humidity/ temperature/ dew point transmitter EE 310 ( has 2 x 4-20 Outputs and 2 Alarm outputs)) Thanks Dominic, would look into that asap, We are a dry corn mill. Would like to see outlet at 212degrees, but it is only about 140 degrees. Actually we are having total 8 same type of bag house system but facing this problem in particular 1 syatem so undersize is not an issue i think. Cleaning of filter bags not not best practice as they are not designed to be cleaned, washed, or anything like that except online by the air pulses. Does the air header have water/dirt in it?
1. Thats what we are thinking for some reason that dust system cant handle the amount of dust. It could be the tubesheet is leaking and needs repair. This indicates your airspeed in your ductwork is below the minimum conveying velocity for the product. More or less than this and you will have a severely weakened pulse. 272 bags per module with an average flue gas flow of 17,000cfm. Thank you Even if the filters are not blinded, the baghouse could be inadequately sized to allow the needed airflow through the system, thus building up pressure on the kettle. Attempt to dry the tubes by circulating clean warm air through the collector and going through several cleaning cycles. Does the Reverse Air Fan spin in the correct direction? I think you need to take those measurements again. can. It could be that the pellets are throwing an increased/decreased dust load on the filters and your cleaning settings are no longer optimal for that mix. Is the compressed air pressure at the proper level. It was discovered that after the bags were changed and the mill started up, that blaine on the cement started to drop after 4 hours of operation. Thanks for your reply! Im going to replace the airlock, the bags have been done but something I have noticed it gets bad on humid days. Would you be able to assist. Have they raised/lowered the temp of the product for any reason? It sounds like you need a faster discharge, we supply fast dumping rotary valves that might help. Fabric Details: Can this be my problem? You need to determine what air to cloth ratio you need for the product. we have a RVD in which we are using three stage steam jet ejector. Thanks for your comment.
Notify me of follow-up comments by email. Inspect diaphragm valvefor failed diaphragm or small particle seated on diaphragm. You could have too high of an air to cloth ratio and the system simply cannot keep the DP lower via the cleaning system. When you are looking at design and maintenance, we talk about them in terms of CFM, number of bags, style of baghouse (pulse-jet, reverse-air) type of bags (aramid bags, top load, bottom load, etc.). Please advice. (pulse jet bag house) Are there any obstructions in the Ductwork System? Any changes to the equipment, conveyors, transfer points?
I have started my plant after 4 months shut down. We have cleaned the filter bags, all 288 of them. M&B Consulting Services. Save my name, email, and website in this browser for the next time I comment. If we have a calculated air volume of 13,12mcubed/sec How do we calculate the gross filtration area required. We take trend data on our baghouses for troubleshooting and it appears that one of my baghouses differential pressure is fluctuating by a whole inch of d/p when its not in use. Does Shaking action take place, as it should? Air to cloth ratio is 1:1. Thanks for sending us the question! This can be detected by listening to each valve at the unit for constant airflow noise. By taking them out and attempting to clean them you may have damaged them further causing more leakage. Many of these issues can be resolved with a simple maintenance procedure; others may require a qualified service technician to implement a solution a particular problem. Insulation helps this problem however it sounds like something else has changed. Any problems with the dryer itself? Is the air pressure at the Pulse Valves within the recommended levels and are all Solenoids and Diaphragms operating properly? Normal systems are designed for 15 25 of vacuum. the cleaning happens only when we stop the extracting fan or close 100% the damper valve and pulse on manual mode
| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. Mandy After every 25-30 minutes bag filter DP reaches at its peak point, then operator opens the vacuum breaker to kill the system vacuum. I have a Very able speed exhaust fan. check and monitor your gauges to see what the pressure is doing. If the air is coming it so fast that its tearing up the bags then it probably is a result of poor design from the system OEM or modifications have been made to the system by non-baghouse engineer or to the operation (all three are very common in the field). Or maybe its part of a multiple compartment baghouse and the isolation dampers between the modules are not sealing correctly. You are getting the point.
Check hopper discharge and 55 gal drum lid for leaks allowing re-entrainment of dust.
Be aware though, that any increase in cleaning frequency will proportionally increase your emissions as well as decrease overall bag life. Is that 70-100 inches of water? In fact, any of those methods will usually cause further damage to the filters as they are not designed to withstand that treatment. Is the cleaning mechanism adjusted to the proper settings? DP get raised from 70 to 100 before surge out and reduced to 70 after surge out. Im not too sure whats causing the problem.
(Namely, the type of unit, filter style, number of filters, fabric/treatment used, air to cloth ratio, total CFM, etc.).
, in our Dust Collector used for venting a Grinding Mill to allow us to maximize the wet material inputs. Are the cleaning pulses at set to the correct duration (0.1 sec)?
Is your dust collector showing signs of trouble ahead? #2 Condensation comes from temperature differences in the system.