For the stock, combine reserved shrimp shells, veggie broth, wine and one tablespoon of tomato paste in large pot. Bring mixture to a boil. Reduce heat and simmer until liquid is reduced to one cup. (about 10 minutes) Drain mixture over a bowl and discard the shells.
For the soup, using the same pot, heat oil and add onion and celery and saute. Add shrimp stock, coconut milk, one more tablespoon of tomato paste and bring mixture to a boil. Combine flour and milk with a whisk and add to the pot. Reduce heat and simmer until thick (about 5 minutes). Add the shrimp and marinade and cook for about 5 minutes.