Can we renew our travel visas in Dalian? What are the requirements? Can we do it twice?

Yes, you can do it in DL Exit Entry Administration on Zhonghua East Road. The service number is 0411-86766108.
The documents you need to prepare are: the passport, the current valid visa, the temporary residence proof and the visa application. Sometimes, the assets certification is needed. For detail information, it is suggested to contact the administraction directly.