Is it permissible to pray in clothes stained with blood, knowing that the questioner's work causes the Dhuhr and Asr prayers to be delayed?

You have no excuse for delaying the prayer past its time. You must prepare a special garment for prayer to perform it when its time arrives. If it is difficult to prepare another garment or to remove impurities from your garment, then it is permissible for you to pray in your clothes, and the impurity is excused to avoid hardship, as mentioned in the Fiqh Encyclopedia and Ibn Abidin's marginalia.