Opamp output short circuit protection
This is completely unnecessary, because the LM358 is already rated for continuous short-circuit to ground of any one output.

Specifically, Note 5 under "Absolute Maximum Ratings" states:


  Short circuits from the output to V+ can cause excessive heating and eventual destruction. When considering short circuits to ground, the maximum output current is approximately 40 mA independent of the magnitude of V+. At values of supply voltage in excess of +15V, continuous short-circuits can exceed the power dissipation ratings and cause eventual destruction. Destructive dissipation can result from simultaneous shorts on all amplifiers.


If you think you might run into problems, a simpler solution would be to put additional resistance in series with the opamp output, inside the feedback loop. For example, 2400 &Omega; would limit the current to 10 mA under all possible conditions, but have negligible effect in normal operation (133 k&Omega; load in parallel with 20 k&Omega; feedback network).







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