The phrase "a separate instance" is correct and usable in written English.
It can be used when referring to an individual occurrence or example that is distinct from others.
Example: "In this case, we need to analyze a separate instance of the problem to understand its root cause."
Alternatives: "an individual case" or "a distinct example."
We'd met to talk about a separate instance of technological intrigue, involving a separate Korea.
BigFix for Servers is a separate instance from BigFix for Endpoints, which is targeted at end user desktops and laptops, and where patches are applied monthly.
In a separate instance in February, Morgan Stanley's mutual funds purchased 5.3 million Zynga shares at a price of $14 a share.
Besides the lakefront property issue, the documents recall a separate instance months later when Mr. Claywell persuaded Mr. Rowland to let the school Mr. Claywell's son was attending auction off a meeting with Connecticut's governor.
On Saturday, insurgent attacks in eastern Afghanistan killed two American soldiers in one episode and one in a separate instance, while two other Americans were killed by a bomb in southern Afghanistan.
While we no longer had an organized sophomore vs. freshman snowball fight, during my sophomore year, J.E. Paino managed to give my roommate Claire Brown a black eye during an impromptu snowball fight, and then gave me one in a separate instance of roughhousing just a few days later!
Twitter is in some ways the best of both worlds, offering a separate browser instance within the app from which to escape the tyranny of the iPad's Safari instance.
For every railroad crossing, a separate ADS instance exists and the same telecommunication infrastructure.
Due to the slowness of loading, and large memory consumption, relevancy evaluation was performed in a separate Eucalyptus instance.
Not an integration with a separate PaaS instance, but as an actual component within your main PaaS, with support from a best-of-breed provider.
Each ISS is managed by a separate IVR instance manager, which coordinates the process of ISS instantiation (i.e., ISS creation, configuration and activation).
