Portable heating device

FIG. 1 is a left perspective view of a portable heating device showing the new design;

FIG. 2 is another left perspective view thereof;

FIG. 3 is a right perspective view thereof;

FIG. 4 is another right perspective view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a left elevation view thereof;

FIG. 8 is a right elevation view thereof;

FIG. 9 is a top plan view thereof; and,

FIG. 10 is a bottom plan view thereof.

The broken lines shown in the drawings are included for the purpose of illustrating portions of the portable heating device that form no part of the claimed design.