Situation: Injecting steam through a 1 1/2" header system with nozzles.
Knowns: steam is used at 110 psi and 280 deg F and a total of 4000 lbs of water are used per day
Question: How are the nozzles sized to accomodate these parameters? Nozzles are typically rated at at lbs/hr at a given pressure.
Also if looking in steam tables at the respective pressure and Temperature the specific volume (sat. liq.)is given as .01782 ft3/lb and the (sat.vap.) is given as 4.049 ft3/lb is this steam volume approximately = to 26 ft3? I would appreciate any help.

First things first....I assume that your pressure is gage pressure.  Then assuming an atmospheric pressure of 13 psia you really are dealing with 123 psia and 280 degrees F.

Secondly, this isn't steam this is water.  If you look in a set of steam tables you will find at a pressure of 123 psia the saturated temperature is listed at 343.17 F (interpolation required).  Since your temperature is less than this you are in the subcooled water region.  

Based on all of this, I imagine that what you meant is that you are using water at 110 psi and 280 F and converting it to steam.

I think that probably the solution to your problem is to determine the steam flow rate that you can supply to your nozzle header.  If all of your 4000 lb/day of water is converted to steam and transferred to your header, then you have 166.67 lbs/hr of steam.  Divide this by the number of nozzles you have, and you should have a flow rate for each nozzle.  Assuming your boiler or heater is a constant pressure process your steam probably is also at 110 psi.  So now you have the steam pressure and the steam flow rate, and now you can pick the appropriate nozzles.

......or I totally oversimplified this and your process is really much more complicated????