I would like to improve the stripping of styrene from an emulsion batch(Semi-continuous batch process).
We transfer batch from reactor to stripper and inject direct/live steam at stripper bottom at 1000kg/h(steam flow) temperature range from 70oc-80oc and vacuum -45kpa to -70kpa
The problem I am experiencing includes:
Hi Rendani,
In order to answer you, I would need more information in terms of the initial concentration of styrene before stripping, what type of impeller and latex viscosity.
Best regards
Odair
I need to know the approximate composition or Tg of the copolymer you're trying to make. It is crucial that any stripping be conducted well above the Tg of the original polymer, to achieve timely results.
It would also help to know the degree of conversion that you experienced before attempting the stripping step. Stripping is designed to remove very small amounts of residual monomer in a well-converted latex. If more than a percent or so is unconverted, then various chasing steps should be tried before resorting to stripping.
You may be introducing thermal degradation during the stripping step, which would account for the loss of solids during stripping. Simple test: Tg via DSC before and after stripping. For stripping, did you ensure a reducing atmosphere (N2 or other)? Simply adding steam would also add ambient oxygen, unless other steps are taken. Oxygen at elevated temperatures would add to any oxidative degradation problems.
HI Odair Araujo
· Initial concentration of styrene before stripping # 5000ppm- 8000ppm
· Latex viscosity # 60centipoise-150centipoise
· Batch size # 35000kg
· Agitation speed #26rpm
my other important question is to determine the amount of steam that i must inject to get optimum stripping time
PLEASE FIND an attached fine that will help you to see the stipper and the impeller type
thanks
Hi Rendani,
I was out of office. I received the data and the attached drawing. I will send you the comments during the day today.
Best regards
Odair
Hi Rendani,
I am preparing the answer with my comments to you. But I am missing an information in order to answer about the steam flow. Please, what is the capacity of condensation of steam in the condenser before the vacuum pump?
Best regards
Odair
Hi Rendani,
According to the data you sent in your messages, please see below my remarks and suggestions:
1- 5000 to 8000 ppm is too high to start stripping. I would suggest you to increase conversion in polymerization process by increasing final temperature (higher than Tg if possible), extra addition of initiator and/or increasing of polymerization time. If you could reach 2000 to 3000 ppm it would be better.
2-The impeller should promote good flow to renew the liguid/vapour interface. If you see the drawing, the flow profile is not favourable. You use the three first impellers. I would propose to invert the sense of the flow of the middle impeller and promote a flow from the top to the bottom.
3- The flow of steam must be equal to your condensation capacity. In this way you can keep your solid content constant. May be you need to cover the external walls of the equipment with thermal isolation material.
Please, if you a allowed, tell me about the particle size , if the product is very foaming and also if it is pure polystyrene (Tg about 100°C?). If the product is Tg 100°C, it would be more difficulty to extract styrene from a glassy polymer. In this case, may be you need also to think about the use of redox system to decrease even more the free styrene.
I hope it helps you. Please do not hesitate to contact me.
Best regards,
Odair
Dear Polymer science researcher
Greeings and very good time to every one. I am going to plan a system for producing styrene butadiene rubber. I read some patents about SBR synthesis for industrial use. Regarding to your experiences would you please guide me, for stating ,how I design a experimental set up(Laboratory Scale setup for SBR emulsion polymerization)? For industrial production I have some figures extracted from some books which I sent you.
Thank you very much for your help
I am looking for your response
Best Regards
Shahla
Who has experiences about synthesize of styrene butadiene rubber?
I have some questions about this project.I appreciate if some one help me to answers to my questions.
Thank you very much for your attention and your time
Best Regards
Shahla Ataei
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