I've played since 2012 and the trade has never allowed me to request more resources than I have room in my storage.
There are some limitations in Trade office and those were introduced 19.7.2016 (Change log) and then changed on the next update (Change log) increasing the limits by 10x
The limits are:
- Item - 1000 - This is the general trade limitation for all items, regardless of their source.
- Resource - Storage Capacity - The limitation of resources is dependent on the storage capacity of the player.
- Refill - 100000 - The limitation for refills.
- Building - 10 - The limitation for buildings.