WHAT IS A GRAVITY PRESSURE
VESSEL? A
gravity pressure vessel is a pipe that hangs
vertically inside a steel lined chamber drilled
and cemented into the earth. Wastes and water
enter at the top of the pipe, are directed downward
to the bottom of the pipe and then back up and
out. Even though the water is always moving,
the pressure at the bottom can be anywhere from
350 pounds per square inch to 3,500 pounds per
square inch, depending on the depth of the vessel.
WHAT CAN YOU DO WITH
IT? The
gravity pressure vessel is simply a very efficient
and continuous pressure cooker. Many desired
chemical reactions are triggered by or made practical
by heating. The temperatures achieved are keyed
to pressure. The higher the pressure, the higher
the temperature, just like in a pressure cooker.
The gravity pressure vessel increases and decreases
pressure as well as increases and decreases temperature
without any moving parts.
GIVE ME AN EXAMPLE.
It is of public merit to destroy certain chemicals
that have been produced, accidentally or intentionally,
or to convert them to some useful material. Examples
of these include the destruction of the concentrated
biomass from a waste water treatment plant, the
elimination of “off specification” chemical
plant production, the elimination of wastes produced
from cleaning process raw materials, the reduction
in volume of low level radioactive wastes, the
conversion of trash and garbage to fuel grade alcohol,
the devulcanization of rubber, and so on. All of
these have in common the factor that these processes
are made practical by efficient means to do the
process.
HOW MUCH CAN A VESSEL
HANDLE? The
water flow rate is between 50 and 8,000 gallons
(200 to 30,000 liters) per minute per vessel.
Waste water has another dimension in that the
concentration of the materials in water can vary
from 0.00001% to 15%. Warmer water is much less
viscous than cold water and flows freely even
at higher solids concentrations.WHAT IS A DRY
TON? A dry ton is the weight of actual suspended
solids, ignoring the weight of water that may
be present in the solids any form. It is computed
from testing samples of the waste. Other solid
or semi-solid wastes are measured in “truck
tons” which is the weight of the waste
on the truck as measured by scales, water content
and all.
ARE WASTES NOT MEASURED
IN GALLONS? Some
wastes that are mostly water are counted in gallons.
The need is to measure the pollution itself.
Some wastes such as Dioxin can cause cancer at
concentration of 0.000,000,000,000,000,2%. The
measure of the absolute amount of pollution or
contamination depends on the nature of the contamination.
WHY IS THE WATER HEATED? When
things are mixed in water, two chemicals that should
react can just sit there side by side without anything
happening. The same is true of oxygen and organic
waste. By increasing the temperature above room
temperature, we speed up the tempo of activity.
As a simple rule of thumb for each 15 degree Fahrenheit
(9.4 degrees Celcius) rise, the speed of a reaction
doubles. In a reaction chamber time is money.
HOW IS THE WATER HEATED? Most
of the heat for the water going down into the vessel
comes from the hotter water coming up from the
bottom of the gravity pressure vessel. The water
going down cools the water coming up. At the bottom
of the vessel, oxygen is injected into the hot
water and wastes mixture. Dissolved oxygen combines
first with the dissolved organic waste, giving
off heat. Note all desired reactions produce heat
and some absorb heat.
WHAT MAKES THE WATER
MOVE? The
water coming up is warmer than the water going
down. Water, like air, is a fluid. The cooler
water going down is heavier the warmer water
coming up. The heavier water pushes the lighter
water up and out. As long as you keep feeding
the cooler water, it just keeps on going.
WHY NOT USE A PUMP? You
can use a pump to start circulation but it is not
necessary. The gravity pressure vessel itself is
actually a pump, considering that water can come
up and out from the vessel at a higher pressure
than when it went in to the vessel. That is the
result of energy injected into the gravity pressure
vessel in the form of chemical heat assisted by
gases in the oxygen that does not react, like nitrogen.
WHAT HAPPENS TO THE ORGANIC
WASTES? Organic
waste is mostly Carbon and Hydrogen in thousands
of different combinations, with a little of each
of the other atoms like Iron, Phosphorus, Oxygen,
or Nitrogen, to name just a few. During oxidation
the Carbon ends up as Carbon Dioxide and the
Hydrogen ends up as water. During acid hydrolysis
cellulose is de-polymerized back into sugars
or one of the over 250 saccharides.
IS
THAT ALL THAT COMES OUT OF THE VESSEL? As
energetic as the reaction is at these temperatures,
some combinations of chemicals can still escape.
A few things like common vinegar or household
ammonia are not destroyed in the reaction chamber.
IS VINEGAR OR AMMONIA
A PROBLEM? These
are natural materials in the ecosystem and far
less of a problem than virtually any industrial
chemical or sludge. They can be extracted from
the gravity pressure vessel discharge to commercial
advantage.
CAN’T WE GET RID
OF THESE TOO? Yes,
but it would take too much temperature to destroy
those trace materials be oxidation. It looks
like it will be better to remove them after the
process.
DOES THIS PROCESS GET
RID OF BACTERIA? The
process destroys not only all bacteria, but viruses
and amino acids as well. No complex biological
materials can survive the process. In the destruction
of pharmaceutical materials waste destructions
of 99.99997% have been recorded. That is destruction
to the point it can no longer be detected. This
is aof vital importance when converting waste
sources to marketable products.
ISN’T THAT 100%
DESTRUCTION? In
measuring things, we can not use the absolute
of 100%. That number cannot exist in an Engineering
or scientific sense. We can get close, but it
is better to say how close, than assume that
we are perfect.
WHY CAN’T EVERYTHING
REACT? A
chemical reaction can be like people lost in
a crowd. You may know that a friend of yours
is at Times Square on New Years Eve, but you
cannot find them. Given enough time you could,
or if you could search faster you could. Chemical
reactions are like that. Atoms that should get
together often cannot find each other.
WHAT DOES TEMPERATURE
HAVE TO DO WITH THIS? Temperature “speeds
up the search.” At the higher temperature,
more chemicals have found each other than ever
would have gotten together at room temperature.
DOES THE HEAT COME FROM
THE EARTH? No.
The earth gets warmer as you go down but only
about 12 degrees Fahrenheit for each 1,000 feet
(6.7 degrees celcius for each 305 meters). At
five thousand feet you only increase by sixty
degrees Fahrenheit. That does not even come close
to the 600 degrees Fahrenheit of the gravity
vessel at the same depth. The earth acts more
like an insulating blanket, keeping the vessel
warm; however, it does not heat the vessel. That
comes from what is going on inside the vessel.
IS THIS TRUE EVERYWHERE? Almost
everywhere. In volcanic areas, it gets pretty hot
one mile down, but we might not want to drill there
for a lot of reasons. We prefer stable areas that
are not plastic or corrosive. Places that are convenient
to drill and not going to move are the preference.
WHAT ABOUT EARTHQUAKES? It
is possible we might cause a small flitter or two
as the earth expands due to the heat we are putting
into it. But we cannot create a fault or put in
enough energy for a significant earthquake. If
anything, we would relieve strain inside the earth.
We would not want to drill through a fault line,
because it might move.
CAN YOU DRILL ANYWHERE? Almost
anywhere. Some rock is harder than others, and
some is trickier. Rock at a steep angle can cause
the bit to drift too far. Very hard rock may need
too much bit pressure and make the hole crooked.
Salt is a special problem, as are places where
oil or drinking water are present that have to
be protected. Each drill hole requires customized
design efforts.
WHAT IF YOU HIT POLLUTION
FROM DEEP WELL INJECTION? We
might. You would have to handle that like oil
or drinking water when and if you come to it.
Experience from nearby places where someone has
already drilled will tell you what to expect.
We also always start with a strata test to find
out what is below before we drill the gravity
pressure vessel itself.
HAVE THERE BEEN WELLS
DRILLED NEAR MOST CITIES? Oil
and gas men have punched holes everywhere I can
think of, and then some. Actually the gravity
pressure vessel to be used to convert municipal
solid waste to ethanol is more like a commercial
or municipal water well than it is like an oil
well. The conversion gravity pressure vessel
is typically 24 inches in diameter (60 cm) and
2,000 feet (610 meters) deep.
IF YOU WERE NEAR WATER,
WOULD THIS WORK? After
you get down below the water level the earth
and rock is dry or a little damp in places. Water
moving under ground against the casing would
require special attention, but that is very rare.CAN
THIS WASTE GET INTO THE EARTH? The vessel hangs
from the top inside of a steel casing cemented
into the earth. The free space between the vessel
and the steel easing is a vacuum just like a
giant thermos bottle. If anything got into that
space it would come up to the ground level and
be captured. Waste cannot get into the Earth.
Water from the earth cannot get into the gravity
pressure vessel.
IF THE CASING IS CEMENTED,
WON’T IT TRY TO EXPAND? Yes,
increasing temperature makes most everything
expand and we have to be prepared for it. The
steel has to flex, be pre-tensioned before cementing,
or simply be strong enough to take the pressure
of being squeezed by the metal as it expands.
WHY DOESN’T THE
VESSEL JUST FILL WITH STONES? Rocks
and stones are pulverized to dust by the wet
oxidation and hot water. It is like super fast
weathering. The flow rate of the water is like
the fastest stream you have ever seen. Rocks
and stones are swept along to the hottest parts
of the vessel and cannot get past. They shatter
into dust. The largest inert particle surviving
the process has been measured at only 20 microns.
WON’T THE VESSEL
GET PLUGGED WITH MINERAL DEPOSITS? Minerals
that are in water do come out when the water
is heated. In time, these minerals like common
plaster stick to the sides of the vessel wall
and pinch off the opening. To stop this, the
vessel is cleaned every few days by a plug that
is forced down to the bottom where it decomposes
from the heat, or with a high-pressure water
spray. This is done without taking the gravity
pressure vessel off line.
DIDN’T THE FIRST
VESSELS CLEAN WITH ACID? Yes,
but to clean with acid, the vessel has to be
shut down, cooled, cleaned, and then reheated.
That took ten percent of the operating time.
The newest models clean mechanically or hydraulically
without interrupting service.
WHAT STOPS THE VESSEL
FROM TURNING INTO A GEYSER? The
hot water coming up from the bottom can flash
to steam as it looses pressure, but it is actually
cooled by the water that is going down into the
gravity vessel. The rate that water can be processed
is in part determined by the rate of cooling
of the updraft. It is important not to start
oxidation in the downdrafting wastes as the heat
produced prevents the cooling of the updrafting
treated wastes.
WOULD
IT BE CHEAPER TO USE AIR INSTEAD OF OXYGEN? The
unit built at Longmont used air at first. But
air is only 20% Oxygen and the Nitrogen takes
up too much space. It fills the spaces between
the pipes until there is no room for the water
to flow. This is especially a problem up near
the top where the pressure is least. The gases
expand as the pressure comes down. As a result
the capacity of the Longmont unit was less
than half of what it could have been. The operators
eventually switched over to Oxygen and the
vertical vessel worked up to expectations for
that generation of design.
WHY NOT ADD OXYGEN AT
THE TOP AT A LOWER PRESSURE? You
don’t want to start the reaction too soon,
because it would release heat near the top and
cut down on the ability to cool the updrafting
water from below. The oxygen not only takes up
space, it cuts down on the amount of water you
can put through the vessel by cutting back on
cooling and increasing water flow friction.
ISN’T CO2 FROM
THE OXIDATION OF ORGANICS A GAS? Yes,
but it stays dissolved in the water as carbonic
acid until the pressure is released all the way,
sort of like a soda pop. The carbonic acid can
be neutralized to limestone. It can also be sold
as a gas. It can also be used as an acid to convert
cellulose to saccharides or sugars.
CAN WE RECOVER ENERGY
FROM THIS PROCESS? Early
attempts to recover hot oil from the Longmont
reactor did not work. The oil simply lost too
much heat while being piped up from the bottom.
Taking heat out at the wrong places also stopped
the recycle of heat that these devices need,
especially when they are not built as efficiently
as they could be. Nonetheless, modern versions
will recover energy by new patented methods that
work on kinetic energy reaction.
WHY ARE THE NEW PATENTS
SO MUCH BETTER? The
key to gravity vessel efficiency is control.
The new unit controls both the rate of heating
and cooling. Some solve the control problem of
retention by re-circulation in the hottest part
of the vessel and uses the re-circulating venturi
to aid in mixing and in dissolving oxygen in
to the water. Once Oxygen is dissolved, the reaction
is very fast, but the trick is to get the oxygen
into the water at the right place. That place
is in the very bottom of the vessel. Some newly
patented vessels are dedicated to perform a unique
task involved in producing marketable products
from waste. Others are designed to convert raw
materials to a product at great efficiency.
WHY NOT USE A SECOND
FLUID TO CONTROL HEAT? A
second fluid is not very efficient in moving
heat around where you want it. First, there is
no control. Second, the heat is in the water
from organic oxidation. You can change energy
balances much faster by changing the percent
of organics in water than you can by transferring
the heat to oil and then transporting this fluid.
The fluid transport pipes and the insulation
take up a lot of space, cutting down on capacity
for the dollar.
CAN’T A FLUID HELP
SUPPORT THE WEIGHT OF THE VESSEL? It
can, but that is not necessary. The pipe is strong
enough without it. It is just another loss of
control as that heated jacket oil is free to
move around and speeds up the loss of heat to
the rock. It also breaks down and attacks the
metal structure of the vessel and the casing.
WHY NOT JUST DO ALL THIS
WITH A PUMP, HEAT EXCHANGER, AND A TANK? It
is a matter of economics. Above 50 to 100 gallons
per minute, the gravity vessel is much cheaper
per unit of production. To develop up to 3,000
pounds per square inch (204 atmospheres) pressure,
and then let it down again, without the solids
destroying the working parts, is not cheap. It
cost more for tanks with thick walls and the
high-pressure valves than the gravity pressure
vessel. For the higher flow range the gravity
vessel is much simpler. The pumped mechanical
systems are for applications under 20 to 50 gallons
(76 to 190 liters) per minute. Simpler gravity
pressure vessel processes such as the conversion
of cellulose to sugars require only 800 pounds
per square inch (54 atmospheres) peak pressure.
IF THIS IS SO GREAT,
WHY HAVEN’T MORE BEEN BUILT? There
is more than one reason, and a project does not
become a reality until every gate has been opened.
In a market as conservative as water and waste
treatment of all kinds, the history of adoption
of new technologies takes many years. By reviewing
the permits that have been published it is revealed
that no states had legislation in place to address
this paradigm shift in treatment and processing
practices and new precedents had to be established.
In some cases new laws had to be enacted.
Each project requires both seed
and construction capital. In most cases the major
capital providers have access to adequate professional
expertise allowing a commitment for construction
funding. The seed funding or those funds needed
to bring an individual project to the starting
gate are actually more difficult. Even accredited
investors rely on “gatekeepers” that
they trust and respect to help judge investments.
Such gatekeepers may or may not have a clear understanding
of the market, the economics, the return on investment
and the control of risk.
In the final analysis each project
involves selling something to a team of participants.
As such each facility becomes a matter of politics.
The individual who finally must make the decision
has the situation where his or her job security
might be threatened by doing something that few
others have done. That is true in government and
private businesses. Others are eager to reach out
for the image enhancement that would come from
leadership. No two cases are exactly alike.
As a result a quilt pattern
of project development occurs around the world.
One project may have its permits, the capital funding,
and a committed client but may lack seed funding
to help stitch it together. Another project may
lack the commitment for capital construction funds.
Another must wait on legislation to work its way
through the system. Another may find itself in
competition with a grant awarded to a marginal
but non-self sustainable competitor. Every gate
must be opened.
