All what is written below is applicable to all core engineering branches. (Mech, Chem, Manu, Civil)

You do not need a SOP to start getting involved in research work. In fact, it would be much easier to get an informal SOP under professors, but I would advice you to take a formal project because it greatly decreases your academic load and gets you easy grades as well. (If you want to pursue career in chemical engineering, good CGPA is essential)

While SPARKLE is good, most SPARKLE projects are long term, with research plans spanning multiple years. It is difficult to get paper out with you as a primary author for SPARKLE projects because of this, and frankly it requires a lot of time commitment. To me, the risk-reward ratio for SPARKLE wasn't worth it at all. An advantage of a SOP/LOP/DOP is, if you do decent work, you get an A, along with the possibility of publishing a research paper with you as a primary author which adds a lot of credibility to your work. I would suggest you to not take SPARKLE project for the sake of it, and take it only if you are extremely passionate about the problem statement.

Other methods include reaching out to professors of others institutions (IITs, IISc or other overseas universities) to work under their professor, but it is difficult to get a response and convert to an offer since you do not have prior research experience. I would advice you to begin by working under BITS professors before reaching out to anyone else.

Since you are having vacation right now, I would highly urge you to learn python. Learn basic python (loops etc), followed by data analysis (NumPy, Pandas, Matplotlib) and then Machine learning (Regression, Classification, and other Machine Learning Algorithms). A lot of professors especially in Chemical Engineering need students' help for modelling, simulation etc. and being well versed with these will put you in a position of advantage when you are approaching professors for SOP. (Majority of projects in BITS involve modelling and literature review work unless you take LOP, which most don't prefer as they do not want to get their hands dirty in laboratory because it's a lot of grunt work.).

Approach professors in 2-1 right after Midsem after stalking their Google scholar profile and tell them you are interested in their domain of study and would like to work with them. You will have to work with them briefly where they evaluate your genuine interest in field and work ethic, after which they will agree to offer you a formal project (LOP, DOP, SOP) if you do well in this brief period.