It seems that your project is a good candidate for Dense Phase system. Now, before this can be confirmed, a complete evaluation of the system: piping layout, equipment involved, plant location (elevation, weather cond., etc.), shall be required.
Even though Cement can be fluidized relativetly easy, due to the length of your system it may required additional nozzles that, when located at the right location, it will insured the product transfer.
Another issue is the type of hopper/tank/silo you will be using as well as the receiving one, codes etc. Is dust a problem? Several questions that once answered will insure the correct application.
We do all the pneumatic calculations in house and are compared against working systems that we have installed in the past.
We have worked with Schlumberger, BPAmoco, ExxonMobil, etc. providing consulting and engineering for Cement, Barite, Hematite, Bentinite, etc, transfered at Onshore and Offshore applications.
Raul Shelton, P.E.
USA Shelco, Inc.
Solids Handling Engineers and Consultants