ABUJA — The Dangote refinery has raised its gantry price of petrol by N85 to N1,350 per litre, and pump prices in Abuja have risen to between N1,400 and N1,450, up from about N1,200 to N1,300 a month earlier. Brent crude closed at $104.87 per barrel on Friday. The Nigerian Midstream and Downstream Petroleum Regulatory Authority said the law does not allow it to fix prices, but that it is monitoring the market with the Federal Competition and Consumer Protection Commission.