How can I legally create an escrow account, a shelter to hide the incoming money so as not to affect the coming offer and comprise?

See an attorney, doing this incorrectly could lead to a fraud charge.

First, offer in compromise tends to take months. Just because you've filled the paperwork doesn't mean that it'll come through in a few weeks. If you set up a separate account and try to hide disability payments - that's tax fraud, tax fraud is a crime, the penalties include huge fines, prison time and forfeiture of the payments you have made on your OIC. Almost every kind of disability payment will issue a 1099 or W-2 next January. The key to a successful crime is the cops CANT ID YOU. Here the IRS will get your head handed to them on a platter.

The short answer is, you cannot: Any money you come into possession of, from whatever source, is a fair game when it comes to the IRS tax debt. They go after people's inheritance money, disability claims, personal injury lawsuits, gifts - whatever. If you try to create something like you are describing, this could be perceived as intentional tax evasion, which could result in criminal tax evasion charges. So don't do it. Instead, disclose your amount to the IRS, and perhaps you can still settle with the IRS if this is the only money you get to live on and you have no other income.