The short answer is no. But ...
In theory yes but it would take wrapping with carbon fiber, replacing the valve with a regulator and getting it hydrostaticlly tested. All of this is not that easy to do and not worth the effort not to mention unsafe.
Moral of the story please don't bother or try it would be unsafe and not worth the effort especially when you can get a new steel tank for ~$85.
Good luck,
MC
Yes, carbon dioxide will liquify under high pressure.
Soft drinks are also known as carbonated drinks. Have you thought why? Soft drinks contain chuge quantities of carbon dioxide under high pressure. The high pressure causes the gas to remain in dissolved state. Hence, when you open the bottle, the pressure falls, and the dissolved carbon dioxide can no longer remain dissolved, and hence escapes off, as fizzing.
Carbonated water is water with carbon dioxide dissolved in it. This is done by placing carbon dioxide under a high amount of pressure. When the pressure eases, the gas is released into the liquid as tiny bubbles.
By dissolving carbon dioxide with pure drinking water at a high pressure.
The critical temperature of carbon dioxide is 304.2 K (31.0°C). At this temperature and above, carbon dioxide cannot exist as a liquid regardless of pressure, transitioning directly from gas to supercritical fluid. It's a key parameter for understanding the behavior of carbon dioxide under high-pressure conditions.
Carbon dioxide is more soluble under high pressure because higher pressure forces more gas into solution due to increased collisions between gas molecules and the liquid solvent. Conversely, under low pressure, less gas dissolves into the liquid due to fewer collisions.
Carbon dioxide is forced into the liquid at high pressure, causing some of it to dissolve (actually, even at normal pressures some carbon dioxide will dissolve in water, but using higher pressure makes more of it dissolve).
Carbon dioxide is more soluble under high pressure and low temperature conditions.
Carbon dioxide exists in various states on Earth depending on temperature and pressure. At normal conditions, it is a gas. At very low temperatures and high pressures, it can exist as a solid (dry ice) or as a liquid.
It depends on the temperature and pressure of its surroundings. check out its phase diagram for more information. the phase diagram is available here... http://www21.wolframalpha.com/input/?i=carbon+dioxide
Carbon dioxide is more soluble in high pressures because an increase in pressure results in a greater amount of gas molecules being forced into solution. This helps stabilize the gas molecules in the liquid phase.
Blood doesn't become fizzy like soda because the quantity of Carbon Dioxide within blood is minimal in comparison. Fizzy drinks require a large quantity of soluble Carbon Dioxide to be forced into the beverage under high pressure just make it possible to insert that amount.