Angel Hair Formation
Dear Mr. Hilbert and Mr. Amrit Agarwal,
I am yet to get file picture of angel hair , streamers. Request you to forward those along with some write up to any of the following e-mail ID :
canjan123@rediffmail.com
or
anjan.chatterjee@hpl.co.in
Regards,
Anjan Chatterjee ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
I have sent a photo to your e-mail as requested ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
Angel hair formation has been discussed here a number
of times.If you search this forum you will get loads of
information. ■
Angel Hair Formation During Pp Polymer Conveying
Please have a look at this:
https://forum.bulk-online.com/search...earchid=192062
R.H. Wohlbier ■
Angel Hair In Pp Dilute Phase Conveying
Anjan,
Since your problem is angel hair and not streamers, you should conclude that your conveying lines are scored (internally roughened). You should check this out as your first step and make sure that the lines are correctly scored. If the lines are scored, you must have an angel hair and fines removal system at the end of the conveying line. Your second step is to check if you have such as system. If you have this system, and since you have angel hair problem at the extruders, your third step is to conclude that this system is not working correctly. Your next step should be to trouble-shoot this system.
If this problem is NEW, it could be due to changes such as conveying velocity, type of PP copolymers you are now conveying, or any changes in the conveying conditions. If so, you should find out what these changes are.
The above advice is based on my about 40 years of experience in pneumatic conveying of PE and PP and other polymers.
If you need my personal help, you may send me an email.
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Email: polypcc@aol.com
Ph and Fax: 304 346 5125 ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
Anjan
We have solved this problem many times for many different customers.
There are several solutions and determining the most cost effective for you first involves an analysis of your specific situation, focusing on conveying velocities, pipe line geometry and construction as well as operation and material properties.
From the analysis, a recommendation can be made in either a conceptual form for you to explore in detail or we can offer a complete detailed engineered solution - which ever you prefer.
If you'd like a detailed proposal or have any questions, feel free to contact me at the e-mail address below.
Regards ■
Angel Hair Formation In Pp Powder Conveying (Lean Phase)
Dear Mr. Agarwal,
This mail is in relation with angel hair formation in our PP plant powder conveying which I have mentioned in bulk - online forum earlier. I thank you all for giving an insight into angel hair formation. The SS conveying line through which PP Powder is being transported continuously to silos is already shot peened from year 2000 ( commissioning year). Moreover with the introduction of a new S & T type heat exchanger at suction side of conveying blower , conveying Nitrogen temperature has also dropped. Is it a fact that the shot peening section of pipe has got smoothened during this six years of operation and creating a problem now ? The softening point of PP material is 155 C. Does the angel hair formation depends on Blower gas flow, gas velocity, conveying rate and any other factor ( please mention them ) and how ? In our case only angel hair formation is taking place ( no fines / streamers). Would you please share some write - up along with photograph of streamer,angel hair etc. to me ?
Remain thankful to you.
Regards,
Anjan Chatterjee
Manager,
Technology Department
Haldia Petrochemicals Limited.
09732541594(M) ■
Angel Hair Fomation In Pp Powder Conveying
Dear Gentlemen,
Do you mean that our existing conveying circuit shot peened section got eaten away and got smoothened. In such case we can check pipeline internals in shutdown condition as I don't know whether shotpeened condition can be checked on line or not.
Ours conveying system has two loops. In loop - 1 virgin PP powder gets conveyed from dryer to intermediate powder silos(2 in Nos) . In loop-2 this silo powder conveyed to another surge silo from which extruder feeding occurs. In between surge silo and extruder there are some other rotary valves like corriolis feeder,solid and liquid blenders etc. Loop-1 length is more than
Loop-2. Will it be helpful to fix a mesh upstream of intermediate powder silos bottom rotary valve to elliminate angel hair formation due to loop-1 conveying.
Would you please share a detailed write up for reasonings behind angel hair,streamer,fines formation during polymer powder conveying.
Eagerly waiting for your valuable input.
Regards,
Anjan Chatterjee ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
Shot peened pipe does wear smooth over time. Many plants can rotate the pipe because the wear is not symmetrical. You need to inspect the pipe internals to see if rotation is an option for you. ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
Anjan,
If shot peening has completely worn out, you will get streamers, not angel hair. If it has only partially worn-out, i.e., some of the pipe is relatively smooth and the remaining part is rough, you will get a mixture of angel hair and streamers. Solution to your problem depends on whether you have streamers or not. If your problem is streamers, the only good solution is replacing the worn-out sections of the pipeline. Since wear of the shot-peening treatment starts from the bottom of the pipe, rotating the pipe 180 degrees will help but not fully cure the problem.
If you have only angel hair problem without streamers, your solution is satisfactory operation of your angel hair removal system.
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Email: polypcc@aol.com
Ph and Fax: 304 346 5125 ■
Angel Hair Formation In Pp Powder Lean Phase Conveying
Dear Gentlemen,
In our case as the maximum length of polymer strip formation is 6 inches so it can be termed as angel hair. We are getting lots of fines too in conveying circuit which are ultimately plugging Conveyor blowers suction guard filters and finned tube coolers.
I think rotating the conveying pipeline by 180 degree in horizontal section will be fruitful but can it be helpful in vertical section too ? Is it a fact that the severity ( i.e. smoothening of pipe wall) in horizontal section is much more than vertical section ? I feel bending at the end of vertical line is prone to angel hair formation and in this respect long radius is less prone to angel hair formation than short radius.
Please feel free to validate my reasoning as I have no early idea on this issue. Would be grateful if you provide a photograph of streamer & angel hair with reasons behind their formation & how to stop this.
Regards,
Anjan Chatterjee ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
You are correct in your assessment that the rotation of pipes in the vertical section will not have the same effect as rotating the horizontal lines.
The last bend in the system is where the velocity in the line is at it's highest value. The use of a long radius sweep will not necessarily reduce the debris formation as compared to a short radius bend.
You can change specific pieces of piping and bends but the answer as suggested in previous replies lies in a complete, systematic evaluation of your entire system.
Not sure why you want to see pictures of streamers and angels hairs if you have so manyof your own but I have attached two photos. ■
Re: Angel Hair Formation During Pp Polymer Powder Conveying
For your information see the site:
http:www.valitec.eu
Using our equipment, it is possible to get rid of any type of waste even with pipes in bad condition. The cost of this long lasting equipment is lower than the cost of a new piping. Eqipments of this type installed in two ExxonMobil plants in Belgium since 1993 and in 2000 are still working satisfactorily in 2007 to get rid of any waste mixed with the pellets at the output of the pneumatic transport. ■
Shot Peening Of Stainless Steel Pipes & Bends
We are glad to inform you that we undertake the process of internally roughening of the Pipe & Bends through process of Shot Peening, which reduces the Angel Hair or Streamers formed while transporting plastic pellets through Pneumatic Conveying System.
Our plant is equipped with automatically controlled shot peening machines for wide range of components of job diameter upto 1 metre with consistent and unerring results. We can deliver Stainless Steel Pipe & Elbows as per the required Grades & Drawing having roughness value as per your Specifications required at affordable prices and short delivery periods.
Please do read the attachment for further details.
Thus, we request you to give us an opportunity to serve you and we assure you our best service.
Warm Regards,
V.C. Chandan
VIKAS METALS
4-4-168, Mahakali Street,
Ranigunj,
Secunderabad-500003.A.P.(India)
E-Mail: vikasmetals@yahoo.co.in
Ph: +91-40-27712995/66385055/9885977337
Attachments
shot peening-solution for angel hair formation (PDF)
■
Angel hair formation during PP Polymer powder conveying
Since last six months we are facing a problem of angel hair formation in our PP plant during lean (dilute) phase of conveying.These angel hair are finally blocking powder flow at extruder hopper causing hopper level indication and no/less flow to extruder. Would you please provide the probable causes due to which this angel hair formation is taking place ? What are the checks should I do ? I am ready to provide you all relevant information/data for your requirement.
Anjan Chatterjee ■