In the key of B minor, the D minor chord is not in the key -- but this is great for romanticism if you use it correctly. The changed note would be an F-natural, whereas B minor contains an F-sharp. If you make sure the F-sharp follows the F-natural -- creating an augmented unison -- it could be a chromatic mediant, which is nifty and good for the late-romantic style. (A good example of a chromatic mediant is found in the beginning of Dvorak's New World Symphony.)
However, a few other unrelated things also come to my attention:
-What key is the clarinet in? I'm not sure what your background is in orchestration, but it's important to know that there are three different clarinets. It matters which one you use, because they sound and are played differently. I can explain this in more detail if you'd like.
-B minor is not a great choice for woodwinds in general. I'd advise using a flat key, if possible, because pianists don't really care but woodwinds much prefer flats to sharps.