The Federal Reserve Board will consider on Monday a proposal to curb its emergency lending powers, a change demanded by Congress after the central bank’s controversial decision to aid AIG (AIG.N), Citigroup (C.N) and others in 2008. A proposed rule, to be considered by the Fed’s Washington-based board in an open meeting, would require that any future emergency lending be only “broad-based” to address larger financial market problems, and not tailored to specific firms.