Returning to Canada from Thailand

Your itinerary:

Thailand - Beijing - Canada

With a layover of 11 hours is definitely eligible for 24 hour visa free transit and you don't need any kind of visa.

You will print out your flight tickets and bring those printouts with you. Also, you will declare at check-in in Thailand that you will travel to Canada via Beijing using 24 hour visa free transit. Here have in mind to ask about your luggage, although if you are traveling on a single (through) ticket, your luggage will be tagged, almost certainly, all the way to Canada. Again, you should ask just for a case.

The reason why you are eligible for 24 and not for 144 hour TWOV (72 hours TWOV was replaced in Beijing a couple of years ago) is in the fact that your layover is less than 24 hours.

Upon your landing in Beijing, you will apply for a temporary entry permit at 24 hour visa free transit counter to be allowed to exit the airport. Please, have in mind that the issuing of this permit when you travel on 24 hour TWOV is at absolute discretion of immigration official on a day of arrival. If your layover is during the day, you will tell that you intend to explore the city, but if it is during the night hours, you are advised to book an accommodation in advance and to bring a printout of a confirmation of your accommodation booking, otherwise you will not be allowed to exit the airport.