can I use the 144 hours free visa in Hangzhou?

Dear Ms,
Dear Mr,

We are two professors from Gheorghe Asachi Technical University of Iasi, Romania, Dumitru Nedelcu and Constantin Carausu which will attend the PCM2016, 20-24 May, 2016 Hangzhou, PRC. I'm a keynote speaker and Host President of the conference.
The Organizing Committee of PCM2016 inform us that we can travel without entry permit, I mean to use 144 hours free transit.
I sent all the information to them and they (Ms. Zha) inform the Hangzhou Xiaoshan International Airport about our flight and the possibility to ask 144 free transit on Hangzhou airport.

Our flight is as follows:
May 19, 13:55 Bucharest-Amsterdam
May 19, 17:20 Amsterdam-Hong Kong International - HKG
May 20, 12:15, Hong Kong-HKG-Hangzhou Xiaoshan Airport

Return flight:
May 24, 12:40, Hangzhou Xiaoshan Airport - Amsterdam Schiphol
May 24, 20:40, Amsterdam Schiphol-Bucharest

I'm waiting forward to receive your answer ASAP.
Thank you,
prof. Dumitru Nedelcu
Gheorghe Asachi Technical University of Iasi, Romania