Also try these modifications,
Change the declaration of card_id array to,
unsigned char card_id[13];
and add one more line inside tne function,
void recieve() //Function to recieve data serialy from RS232
{
unsigned char k;
for(k=0;k<12;k++)
{
while(RI==0);
card_id[k]=SBUF;
RI=0;
}
card_id[13]=’ ’;
}