They are tormented for whatever length of time and intensity their sins have made them eligible for. Their works will determine that. Then they at consumed and it is destroyed---sinners and sin completely gone forever. That is what happens with fire. It burns till there no longer any fuel to feed it.
Isa 5:23 Which justify the wicked for reward, and take away the righteousness of the righteous from him!
Isa 5:24 Therefore as the fire devoureth the stubble, and the flame consumeth the chaff, so their root shall be as rottenness, and their blossom shall go up as dust: because they have cast away the law of the LORD of hosts, and despised the word of the Holy One of Israel.
Isa 47:13 Thou art wearied in the multitude of thy counsels. Let now the astrologers, the stargazers, the monthly prognosticators, stand up, and save thee from these things that shall come upon thee.
Isa 47:14 Behold, they shall be as stubble; the fire shall burn them; they shall not deliver themselves from the power of the flame: there shall not be a coal to warm at, nor fire to sit before it.
Mal_4:1 For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly, shall be stubble: and the day that cometh shall burn them up, saith the LORD of hosts, that it shall leave them neither root nor branch.
You didn't quote the verse before Rev 20:10----
Rev 20:9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them.