Tuesday, April 28, 2015

The Production and Utilization of Renewable Methanol in a Nuclear Economy

10.7 MWe rated methanol electric power plant at Point Lisas, Trinidad (Credit: Mendenhall Technical Services)
Terrestrial and off-shore nuclear power plants could safely and economically provide all of the base load electricity requirements for future carbon neutral  industrial economies. The additional-- peak load-- electrical demands for an industrial region could also be supplied by carbon neutral methanol electric power plants-- if nuclear electricity was also utilized to produce renewable methanol derived from biowaste and waste water resources

Methanol (CH3OH) is, of course, the simplest alcohol, producing only carbon dioxide (CO2) and water after combustion with oxygen. The production of methyl alcohol through the pyrolysis of carbon based materials and their distillation has been known since the time of the ancient Egyptians. Modern techniques of methanol production utilize pyrolysis to produce syngas (synthetic natural gas),  a gaseous mixture of consisting of carbon monoxide, carbon dioxide, and hydrogen  that is then converted into methanol.

Since approximately 65% to 75% of the CO2 content is wasted during the  synthesis of  syngas into to methanol, introducing additional hydrogen into the synthesis process could potentially increase the production of methanol by three to four times. Sources of carbon neutral hydrogen could, therefore, be produced through nuclear, hydroelectric, wind, and solar electric power through the electrolysis of water.

Plasma arc pyrolysis plants, a commercial technology that's already in existence,  could be used for the conversion of urban and rural biowaste (garbage and sewage) into syngas.  Additional hydrogen can be added to the mix through the production of hydrogen through the electrolysis of water at an electrolysis plant. The syngas and additional hydrogen can then converted into  methanol at a  alcohol methanol synthesis plant.

Diagram of a methanol biowaste complex for the production of methanol and electricity.

Carbon neutral sources of electricity could come  from nuclear, hydroelectic, wind, and solar power plants.  Because the sun doesn't always shine and the wind doesn't always blow, wind and solar facilities only offer intermittent supplies of carbon neutral electricity to the electric grid.  While hydroelectric power plants can supply carbon neutral electricity to the grid 24/7, this renewable energy source  has already reached its maximum capacity in the US and can actually supply less power to the grid during periods of drought-- as is currently the occurring in drought stricken California.

Nuclear power plants, on the other hand, can supply carbon neutral electricity to the grid 24 hours per day.  Except during periods of refueling (once every three years), current light water nuclear power plants in the US have an electrical capacity exceeding 90%. Nuclear power currently produces about 20% of America's electricity supply. But there is currently enough room-- at existing US nuclear sites--  to increase nuclear power production  in the US by at least four to five times the current nuclear capacity without the need to add new locations within the continental US. This could easily be done by gradually adding the next generation of Small Modular Reactors (SMR) to existing sites over the next twenty to thirty years.

A methanol complex using carbon neutral electricity from nuclear and renewable energy could produce methanol from the pyrolysis of urban and rural garbage and sewage-- solving the problems of urban and rural refuse while also producing clean energy. The production of hydrogen from the electrolysis of water could substantial increase methyl alcohol production. Domestic sources of carbon neutral methanol could then be used to fuel methanol electric power plants during peak load demands.  The production of electricity from a methanol electric power plant could be further increased if the waste oxygen from the production of hydrogen were  utilized during fuel combustion instead of air which contains only 20% oxygen and  80% nitrogen. 

While the CO2 produced from a methanol electric  power plant could be exhausted into the air without increasing the net amount of CO2 in the Earth's atmosphere, the waste carbon dioxide from the  flu gas could also be recycled.   Post combustion and pre- combustion CO2 capture facilities can collect 85 to 90% of CO2 from flu gas. And power plants that used oxygen can capture as much as 90 to 97% of the CO2 produced from flu gas. Pumping the waste CO2 into the methanol synthesis plants could nearly double  the production of  renewable methanol if even more hydrogen is added to the mix.

Any excess production of methanol from a methanol electric complex would be a valuable commodity that could be exported. Exported methanol could be used  for the base load production of electricity in areas with no access to nuclear power or it could be converted into gasoline or dimethyl ether for trucks and automobiles. Methanol would also be of value to industrial chemical companies.
TVA’s, Sequoyah Nuclear Plant (Credit TVA).

Despite the accidents at Fukushima and Chernobyl, terrestrially based commercial nuclear power are still the safest source of electricity production ever invented. But floating commercial nuclear reactors deployed several kilometers off marine coastlines or even deployed far out into the ocean could enhance nuclear safety even further.

The Earth's oceans, of course,  are certainly no strangers to nuclear power. There are over 140 nuclear powered ships and submarines roaming the Earth's oceans and seas  with more than 12,000 reactor years of marine operations  accumulated since 1954. 

More than 100 million Americans currently  live within 80 kilometers of a commercial nuclear reactor. But undersea electric cables more than 1000 kilometers away from coastlines  are possible.   Floating nuclear power facilities  could be deployed more than  300 kilometers from an American coastline while still being within the US's  200 nautical mile (370 kilometer) exclusive coastal economic zone.  Such floating reactors could, therefore, be deployed far beyond the 80 kilometer exclusion zone recommended by the United States during the height of the  Fukushima nuclear accident.

Of course, a Fukushima type of incident would be impossible for a floating nuclear facilities located in the open ocean since water  is a natural coolant for light water reactor fuel. Ocean waters would serve as an infinite heat sink for fissile material-- essentially making nuclear meltdowns impossible for floating reactors  placed below the water level. Floating nuclear reactors placed dozens of  kilometers offshore would also be immune to potential damage from earthquakes and tsunamis.

The safety of floating nuclear facilities from potential harm from terrorist or other hostile political groups could be enhanced by naval security from  US Coast Guard or other US government authorized security forces. Potential damage to the reactor from a  torpedo could also easily be prevented with an extensive network of  torpedo nets surround the nuclear power facilities.

But, again, even if an attack on a floating nuclear facility was successful, the ocean water would immediately prevent any melting of the nuclear material to occur.  Water also acts as a natural radiation shield. Just a few meters of water can  reduce ionizing radiation to harmless levels of exposure near the radioactive material.

Japanese Methanol Tanker (Credit: SHIN KURUSHIMA DOCKYARD CO)

Ocean Nuclear power plants could also be remotely deployed, more than a thousands of  kilometers away from coastlines for the production of electricity. Methanol powered ships could transport garbage from coastal towns and cities to floating biowaste pyrolysis, water electrolysis,  and methanol synthesis plants remotely powered by underwater electric cables from Ocean Nuclear Power plants just a few kilometers away. The methanol could then be shipped to coastal towns and cities all over the world for the production of electricity or for conversion into gasoline or dimethyl ether for diesel fuel engines.

First Methanol Fueled Ferry (Credit Stena Line)

Combined with nuclear and renewable energy, renewable methanol fueled peak load power plants  could finally end the need for  greenhouse gas polluting coal and natural gas power plants in the US and in the rest of the world.

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