Electric Timer With a Micro-Controller
Some remarks:


If this is a one-off, buying 24 simple timers might be cheaper. 
an AVR being mentioned as not being suited for industrial work was likely due to Atmels not-perfect record of being able to deliver. For a one-off this has no relevance.
whether a uC-product is suited for industrial use depends mostly on the curcuit around the uC, not on the uC itself.
if you need more I/O, consider I/O extenders (I like MCP23017).
the 16F877 was once THE PIC to pic, but that time has passed. There are better ones now, consider at least a 40-pin 18F chip. (But personally I would go for a Cortex chip).