Drain for washer/dryer combo

I am moving into the apartment upstairs in the building I am renovating. The place came with a stacked washer/dryer combo unit that I have to move from its original location. The only place I can find that it makes sense to relocate it is in the corner of the oddly shaped kitchen. My question is about the proper drain system for the washer. The old location looks like it drained into 1 1/2 inch pipe. I was always used to a washer draining into a laundry sink. My question is, can I tie it into the kitchen sink drain, which is also 1 1/2" pipe, without a laundry sink? Would I need a standpipe or something to hold any excess water form the washer? If that would work, it would solve many problems! Thanks!

Modern washers empty their water very rapidly and this requires a 2" drain. Yes, they also use a standpipe that must be trapped. When you used the laundry tub as a drain, you got away with it because the tub held the water until it drained through the small drain. Now, it is possible that this stacked washer does not drain as rapidly as standard washers, but it still needs a trapped standpipe. Washer drains hoses hang into the top of the standpipe so there is an air gap. You do not make a solid connection from the hose into the drain.

Your inspector will not allow this to drain into a 1½" drain, and probably will not allow it to share the kitchen drain at all. We don't know for sure what code you are under, but get the permit first, before you try to do a lot of work which may be disallowed.

A plumber can install a proper drain, as long as you have a sufficient amount of cubic dollars available.