If you pass 5.5mA from a 1K ohm load, then Vout is 5.5mA * 1K =5.5volt, and circuit saturate before reaching this load.
your circuit works with 5 volt supply and Vcc = R1 * 5.5mA + V_ce + R2 * 5.5mA
for 5.5mA output and RL=20K, you need a supply voltage 20K*5.5mA+..+..> 100V
You need a supply voltage bigger than 100V, No opamp can handle this voltage and this circuit not works a for 20k load.
You can use this circuit instead:
opamp power is 5V,
Resense = 500 ohm
for 5.5 mA output -> vin(VDC) 2.75 volt
VCC = 20k * 5.5ma + 500 * 5.5ma + V_CE ~ 120 volt is ok and Q1 should handle 100 volt (minimum (120-112.75) volt!)