Most posts are about planning and a container and 'nuf said. The (other) importsnt part you need to address is food hygiene and safety. The unit must be registered if you sell or give away the honey. This is mainly down to environmental health officers (EHOs). If you have a sketch and some ideas then go to them before you spend any money and you'll find them helpful in seeing that you meet requirements. Even if it is just a hobby they'll give some help. For example, although hot water has been mentioned, there are a number of complications with even what appears to be a simple plumbing job as temperatures are specified - for safety and legionella where appropriate - so easiest to go to the EHOs before fixing your ideas on any system. One other comment on steam cleaning. It can be a disaster. There are problems with condensation, differential expansion of cladding etc. I've seen a lot of expensive damage done with large steam cleaners. Don't forget electrical safety systems for containers are not the same as for a domestic/traditional building.