Setting ulimit values without /etc/security/limits.conf


I'm running into problems with virtual memory on my router. I need to increase the virtual memory limit of one my processes to enable rclone to sync after successful torrent download.

See here:

What do I need to do given that there is no /etc/security/limits.conf I can edit to change the amount of RAM? Is there any other way to increase ulimit -v for a specific user?