Every corporation, association or person, now or hereafter exercising or claiming the right to carry or transport natural gas by or through pipe line or lines, for hire, compensation or otherwise, or now or hereafter exercising or claiming the right to engage in the business of piping or transporting natural gas, or any other person or persons, now or hereafter engaging in the business of buying and selling or transporting natural gas within the limits of this state, shall not have or possess the right to conduct or engage in said business or operations, in whole or in part, as above described, or have or possess the right to locate, maintain or operate the necessary pipe lines, fixtures and equipment thereto belonging, or use in connection therewith, concerning the said business of carrying or transporting natural gas as aforesaid, on, over, along, across, through, in or under any present or future highway, or part thereof, or elsewhere, within the state, or have or possess the right of eminent domain, or any other right or rights, concerning said business or operation, in whole or in part, except as authorized by and subject to the provisions of this act, except, further, and only such right or rights as may already exist which are valid, vested, and incapable of revocation by any law of this state or of the United States.