-- create or replace directory FOLDER as 'C:/ORA_EXPORT';

declare
  l_amount number := 32767;
  l_buffer raw(32767);
  l_output utl_file.file_type;
  l_dir nvarchar2(32767);
begin
  l_dir := 'c:\\ora_export';
  l_output := utl_file.fopen('l_dir', 'blob.txt', 'wb', l_amount);

--    dbms_lob.read(l_blob, l_amount, l_pos, l_buffer);
--    utl_file.put_raw(l_output, l_buffer);

  utl_file.fflush(l_output);
  utl_file.fclose(l_output);
end;