Q: When there is no priest available, a lay minister may expose the Blessed Sacrament for adoration. Is it true that that person may not use incense because only a priest or deacon may do that?
Check the liturgical book Holy Communion and Worship of the Eucharist Outside Mass.
Paragraph 91 speaks of the minister, and the only restriction on a non-clergy minister is that there is no blessing of the people with the monstrance.
Paragraph 93 says that the minister incenses the sacrament. That means the clergy or lay minister who is leading the service.
Paragraph 94 refers to a priest incensing, but that is when the ceremony takes place immediately after mass – so that minister will be a priest.
Paragraph 97 addresses benediction, which can only be given by the priest or deacon. Before he gives the blessing, he incenses the Blessed Sacrament. During the blessing in paragraph 99, there is no incense nor bells.
So if a lay minister is exposing the Blessed Sacrament, he or she may incense at the beginning (91). Apparently there is no second incensation at the end when there is no priest or deacon to give the blessing.