Yes, but the OP is not talking about a standard fixed deposit account, which would not be tax free. The tax free time deposit account he is talking about is one of the savings deposit type accounts, where you have to deposit the same amount every month for the term of the account.
From Krungsri's website:
So this account cannot be used to deposit the OP's 800k, since the maximum allowed deposit per month is THB 25,000.