Here is a video with the engine ring:
https://www.youtube.com/watch?v=MQZn8G28n1s
As there is traces of blue paint I imagine some debris from the cockpit/plane body has hit it at some point.
Can anyone tell if that ring is from right or left side engine?
UPDATE:
btw. the left rear door (I think):
http://pierrecrom.nl/mh17#pic-32
(The hole on that door most likely is not caused by shrapnel.)
UPDATE2: it's the right side rear door of the cabin, not left
UPDATE3: The door was left on the field, there, somewhere????:
https://pbs.twimg.com/media/B3YvSEZIMAAewo9.jpg