Amplify DC output from CT circuit
No burden R shown, so CT voltage could be dangerously high if it's not included in your CT. 
If the current is non-sinusoidal, then you'll probably need to digitize at least 500-1000 times a second to get a reasonable result. I assume by a 1024 bit ADC you really mean an 8 bit ADC. 
Using a peak detector is ok for sinusoidal current flows but the losses in doing your rectification the way you have shown will kill your accuracy (Vf for the diode) and is only valid for the positive peak.

I'd suggest you read this. 

Look at the full wave rectifier schematic and details starting at Figure 17

 


As you can see you don't actually need a peak detector once you have a full wave rectifier. You can digitize the result with any reasonable MCU that includes an ADC with your required resolution.