Recent studies have shown that the supply of crude oil from Alaska's North Slope will soon decline to sub-economic levels and that production will then cease. Alternatives are under consideration that would continue to make use of the Alaska pipeline and to generate revenues from the large natural gas resources in that region. The pipeline was designed to maintain crude oil at a sufficiently high temperature to allow it to be pumped while at the same time protecting the fragile Alaskan permafrost. From the standpoint of the existing thermal design of the pipeline, consider the feasibility of transporting the following alternatives: 

(i) Natural gas

(ii) Liquified natural gas

(iii) Methanol

(iv) Diesel fuel

Your considerations should include 

(a) Temperature required to transport each candidate product

(b) Insulating and heating capacity of the existing pipeline

(c) Effect on the systems in place to protect permafrost
(d) Use of the existing crude oil pumping stations