Is the Mandate of Heaven similar to the Egyptian concept of a pharaoh?
The short answer to your question is no. Egyptian pharaohs were considered to be the human manifestation of the god Horus; and was responsible for the annual flooding of the Nile which made Egyptian civilization possible.. As such, they were considered divine. It was highly improper to even look upon the pharaoh, and to touch him unless he specifically requested it was punishable by death. Precious few Egyptians ever saw the Pharaoh, as he remained hidden from their view. It was for this reason that his likeness was often portrayed in statues.
The Mandate of Heaven was used by the Zhou dynasty rulers to justify their rule. It was more akin to the concept of Divine Right. It was believed that heavenly forces were closely connected with events on earth; and those heavenly forces chose an earthly ruler based on his particular merit. The ruler was commonly known as the "son of heaven" and presumably acted as the intermediary between heaven and earth. As long as he ruled fairly and justly, harmony between heaven and earth was maintained, and his rule continued; however if he acted unjustly, that harmony would no longer exist and the heavenly forces would choose another ruler. This idea was used to justify the overthrow of the Shang dynasty; and carried some validity well into the twentieth century.
So the Egyptian Pharoah was considered divine; whereas Chinese rulers were not; however they were divinely sanctioned. They could be removed if they did not rule fairly and justly; the Pharaoh was only removed by death.
Egyptian rulers saw themselves as Gods and immortalized themselves with pyramids and statues. In Chinese culture, rulers felt that Heaven blessed the authority of the ruler and could withdraw its mandate and could transfer its mandate to who could rule the best. The mandate of heaven is a traditonal part of the Chinese philosophical culture.