Chemical Engineering Eligibility

Yes, you can easily get admission in B.Tech without any problem you will get admission in 2nd year directly.

Only through 12%, you cannot get this college if you have JEE Mains good score card, then you can get this college.
https://www.shiksha.com/college/dr-d-y-patil-institute-of-engineering-management-research-dypiemr-akurdi-pune-35068

You need to clear JEE Mains to get admission in this college and course.
Age Limit for JEE Mains 2019: Candidates whose date of birth falls on or after October 01, 1994 are eligible to appear for JEE Main 2019 Examination.
If you have the age according to the above mentioned criteria then you can appear for JEE Mains and then get into this college
For more details, check out the link below:
https://www.shiksha.com/b-tech/course/b-tech-in-chemical-engineering-indira-gandhi-institute-of-technology-igit-orissa-other-191568.

You can directly approach the college for admission in Diploma in chemical engineering. There is no entrance exam.

Please refer this link to clear all your doubts:
https://www.ucalgary.ca/future-students/graduate/explore-programs/chemical-petroleum-engineering-master-engineering-course-based

According to my knowledge, if you are graduate in chemistry and post graduate in polymer Science, so yes, you are eligible to do ME in chemical engineering.

No, you are not eligible for UGC NET. You have to complete your Master's degree first, then only you will be eligible to appear for NET.

Yes, you can get admission in any branch with this marks in this college.

Not sure about your CET score but you can get chemical engineering with help of your JEE Mains marks.
You need to wait for 2nd or 3rd CAP round. Hope this will help you. You can ask if you have any queries in comments.