Modified 9/11/2001: Extensive additions: added pump construction details, computer control system details, and modified the storage construction details.
Modified 11/7/2001: Added basic non-metal boiler construction description and a note regarding use in submersible pumps.
The modification is an upgrade to use a low cost computer controlled steam powered pump, powered by electricity or natural gas or other means, augmented with passive solar power.
The concept of passive solar power is a proven technology, gone into in vast detail in the book "Passive Solar Design". This invention is not patentable, because it is based on a steam pump, the patent on which expired more than a century ago, and passive solar research done by the U.S. Department of Energy and Solar Energy Research Institute, which falls into the public domain is is therefore not patentable. That this is so is a benefit, not a detriment.
Let's say that all current oil well pumps were converted to steam pumps, where natural gas or electricity heated water to steam to drive the pump. This would actually be a slight to moderate improvement over existing methods, in and of itself, in terms of efficiency, because the Stirling cycle engine (steam engine / steam pump) is the most efficient means known to convert heat into mechanical energy.
But this small efficiency improvement is not the heart of the proposed modification.
After the steam drives the pump, the heat of the steam is converted into mechanical energy, and the temperature of the steam falls from 212 degrees to 80 to 100 degrees in the process.
Normally, to just use fuel to bring the water temperature back to boiling is to raise the water temperature from 90 degrees back to 212 degrees, a temperature increase requirement of 122 degrees.
This improvement uses a passive solar heat generation and storage layout to use solar heat to raise the water temperature from the 90 degree condenser temperature up to 180 degrees. Then, fuel or electricity only needs to be used to raise the temperature from 180 to 212 degrees, a temperature increase requirement of only 32 degrees.
Do the math: use fuel to increase water temperature 32 degrees, or use fuel to increase the water temperature 122 degrees. This works out to a savings of about 1/4 as much energy as it would take to raise the water temperature 122 degrees. At the lower latitudes of Texas, Oklahoma, and California, it works out closer to 1/5 as much energy.
I've been around in Texas and Oklahoma, and I never witnessed any passive solar installations in operation. I rode a bicycle through the Oklahoma countryside over 50 miles, saw hundreds of oil pumps, but no solar.
The solar and steam technologies are proven, but have never been applied
to this type of application. It gives US domestic oil producers a competitive
advantage, because it makes transportation costs more of an issue in the
total price of fuel. Arabs have to ship crude oil thousands of miles, domestic
producers only hundreds of miles.
Without going into too many details, a boiler can be constructed that contains no exposed metal for about $300 for a simple efficiency improvement setup, or $1500 for a high capacity boiler for both pump and steam injection steam supplies.
The boiler would be made of fairly thick rebar reinforced concrete. Two hanging rack supports would be cast into the concrete by placing them into the rebar array before the concrete is poured. After the concrete cures, the interior of the concrete tank is sprayed with fiberglass.
The rack would be made of two high strength steel bars. The bars would be placed inside high temperature plastic pipe, and the empty space filled with sand to allow for heat expansion and contraction. The plastic pipe simply insulates the steel from contact with the water.
This rack, consisting of these two support bars and possibly linked with plastic encased crossmembers, would hold an array of electric heating elements.
The construction of the heating elements is similar to the support racks. Electric heating filament, similar to those found in certain electric heaters and toasters, are run inside of high temperature black pigmented plastic pipes, and black tar sand is used to fill the empty space inside the pipes. The resistance and thickness of the filaments are designed to produce a working temperature range of 250 to 300 degrees Fahrenheit.
The heating elements are secured at the ends with springs which are connected to heat resistant anchors at the ends of the pipe. Components of these types that can withstand the operating temperature are readily available. These pipes are sealed at the ends, and the insulted wire for the power supply are attached with fused multiply flanged seals.
The heating element pipes are then hung from the support racks. At the bottom level of the tank, the heating pipes are arranged in triads. This way, the inlet water from the solar preheat tanks can be routed into the tank through an inlet pipe, and this inlet pipe can be threaded between the triads, so that there is maximum heat concentration directly incident upon the inlet water before it exits the inlet pipe and enters the tank. After the pipe passes between a triad of heating pipe, the pipe is routed back 180 degrees to flow back through the next triad in the tank bottom.
The water inlet and the steam outlets pass through a triple flanged seal in the tank wall. The seals are chosen for a greater heat expansion coefficient than the pipe or the concrete, coated with high temperature grease, and then placed onto the rebar array before the concrete is poured. The inlet and outlet pipes and the support pipes should be grooved, and the seals should be directly cast onto the pipes.
During operation the pressure will flatten the flanges away from the pressure, forcing the grease to seal any small deficiencies in the contact between the concrete and the seal. This pressure against the other side of the flange (closer to the exterior of the tank) will keep the grease from being forced out of the seal. Three flanges means that there will be no possibility of loss of steam pressure through these seals.
The top of the tank is formed out of very thick rebar reinforced concrete coated with fiberglass. A series of male / female concentric mating grooves between the tank lid and the top of the side of the tank are grooved into the lid and the top of the sides of the tank. A flexible rubber seal coated with high temperature grease between the mating surfaces will prevent any loss of pressure through the seal, and the weight of the lid should be enough to contain the pressure if the lid is made thick and heavy enough.
This type of design provides additional failsafe against valve or computer control failure, because if the pressure ever rises very far above design specifications, the excess pressure will raise the let and the excess pressure will safely escape. The lid would be lifted slightly, not blown off, and the excess pressure would equalize itself.
Details beyond this need not be given regarding the boiler construction past this basic concept. It is widely known that appropriate sealing materials exist, and that this type of construction can easily withstand the steam pressure.
I should be able to build a computer controlled steam pump for a medium sized capacity oil well for less than $1000. For the largest wells, this cost should not rise to more than $1500. This would include the steam pump, the computer controls, and all the valves, sensors, and wiring.
The pump body would be sand casted from high temperature resin or plastic, as would the pistons, valves, and rods. Steel corrodes, and requires the use of anti-corrosion agents and a complicated water quality and chemical composition monitoring system, where this approach needs no such additives.
My approach would be to find the total horsepower requirement for the pump, calculate the required piston diameter and stroke, then go to the catalog and look up teflon piston rings for the next largest size piston, and design the piston to use this ring. The same procedure would be followed for the teflon valve seals, using steam flow requirements for determining the valve sizes.
The rest of the pump design is rather obvious, except that the body would be designed around the piston diameter, and cast in two halves, one having a male boss extruded around the perimeter of the mating surface, and the other half would have a female channel, so a sealing gasket can be placed into the mating channel and the two halves can be mated together and then clamped down to form an airtight seal.
High capacity submersible oil pumps can be upgraded with the efficiency
improvement by raising the pump, removing the power drive and replacing
it with a cable drive, and then driving the pump from the surface via the
If I, or someone else who was actually competent, wrote the control program and designed the sensor and control systems, the device could be made entirely fail-safe. My accomplishment with the railroad safety invention, another computer controlled fail-safe system, proves that this can be achieved. There has not been a single instance of a head on train collision in the United States since 1987, when the railroads installed the system. I did not write that control program, or it would have also prevented rear end collisions. However, I have the assembly, C, and C++ programming experience and background to be capable of writing either it, or the control program for the steam pump.
A number of different companies offer sensors and fluid / steam control valves that are certified for use in nuclear power plants at a very reasonable price.
I would install a system comparable to that of the space shuttle control computer bank, except that my control system would only use three computers rather than five, since human life would never be put at risk. A simple safety interlock on the entryway into the underground pump that prevents entry if the steam pressure exceeds a given value, and redundant pressure sensors and indicators that can be examined before entry, combined with posted warnings and instructions, can easily avoid any possibility of this danger.
The three computer boards (currently as of this writing) would be off the shelf Pentium motherboards, with a minimum amount of RAM, running a control program in either freeDOS or pure assembly language. These three boards can currently be obtained in the proper configuration for less than $150, or less than $100 when bought in quantities of 50 or more. This price usually holds true for off the shelf low end or borderline obsolete motherboard / CPU combo boards.
The actual control program is not complicated, and could be written in 30 days. All the program has to do is read the serial ports for the sensor values and make adjustments to the control valves and servos in response. The valves and sensors would take the form of three independent systems, each capable of overriding the others in order to lower boiler temperature or control steam pressure or distribution pathways. Each would monitor the democratic votes cast by the other two, and if an error condition arises in one of the boards, the other two will reinitialize and reboot the malfunctioning unit. Error logs would be kept, and upon recognition of the existence of a failure pattern, the computer would call via telephone or wireless for human assistance, to repair the faulty unit. If the computers failed to check in once (or more) a day with the reporting station, it would automatically be recognized as an error condition and a maintenance check would be made, fist via remote means, then physically if required.
The computer control systems will have the capacity to completely disable the steam system. Each board sends out control signals to control valves and servos that automatically shut down the boiler and release the pressure if the correct encoding of signals is not received on a regular basis.
Let's say we are in Texas. The sun heats stored water to an annual average (including after dark heat storage) of 180 degrees at the latitude of Texas. Of course, one needs to have a sufficient number of black plastic 55 gallon drums or suitable substitute heat storage medium materials to adequately meet the supply and storage requirements, so that at night in winter, the heat will not fall below 150 to 160 degrees by the time the sun rises again.
That this can be done is more than obvious. Read the book "Passive Solar Design". There is no theory there, only known and proven fact. Don't be frightened off by the sheer size of this book. The entire second half is comprised of solar tables for each latitude and longitude, and of the first half, the book is printed in large type, and contains vast numbers of diagrams and photographs, many of which are full page or two page. The concepts presented in this book are neither complicated or technical: it was written for the layman.
One uses the solar constant tables form that book, and with their calculated water flow requirements for the pump's capacity in CFM, calculates the number of hot water storage 55 gallon drums required.
Then one bulldozes out an appropriately sized area, creating a 5 foot high hill that runs east and west. The south half of the hill is then bulldozed out, and styrofoam panels installed on the back (south facing, east-west running) wall and floor. Then one installs the 55 gallon plastic drums and plastic pipe to connect them.
Then one builds a sparse frame out of wood or steel or aluminum, and covers the entire area with a clear sheet plastic greenhouse. One installs one more sheet plastic greenhouse around the first one, leaving a little air space between the two, and then installs a hard plastic or glass greenhouse around that, to create a triple insulated greenhouse.
A cheaper method would be to use two layers of clear plastic sheeting two form the inner two levels of greenhouse, and use a wall constructed of standard glass privacy brick as the outer layer. Because this type of glass has lesser optical qualities, slightly more total surface area would be required, say perhaps an additional 5 to 10 storage drums, but this would be more than offset by the cost savings of using the privacy block, and the privacy clock is much more resistant to passing storms and hail.
A fail-safe computer monitoring system for the steam pump, that has the capacity to regulate the system and call for human assistance when required, about $200 to $5000, depending on where one acquires it. A high school senior can build that for $200. IBM would likely want $5000.
Say the well owner does their own construction. This amounts to a total of about $5000 for the entire installation, assuming that the Oklahoma or Texas petroleum organizations have published construction plans and written the computer control program.
This would easily pay for itself in a single year. Notice, that's 1000 gallons per hour, not 1000 gallons per day.
So, unless the Arabs have taken over all the banks, there is absolutely no problem obtaining the financing to reopen a closed down oil well. The vast majority of US oil wells that have closed (by the thousands) have closed simply because it costs more to pump the oil than the oil can be sold for. Costing $40 to pump $31.50 worth of oil is a recent example that caused operating oil wells to be shut down. (from NBC News).
Do the math above. Instead of $40, it would cost $8 to $10 to pump that 31.50 worth of oil, after this improvement is installed.
In a worst case scenario, where Texas saw cloud cover for 365 out of 365 days in a given year, with it raining 30 percent of the time, the average water temperature would never fall below 140 degrees, which means that no profit was being made at all the first year, because all the profit had gone to pay the financing on the modification.
After another six months to a year of this total cloud cover, the financing would have been paid, and the well would begin turning a profit.
There is no doubt of this. The technology involved is proven, but no one seems to have noticed its potential in the field of pumping oil until now.
There are some other more sophisticated modifications that apply, such as using a large amount of water as heat storage, and using a much smaller amount of carbon tetrachloride (CT) as the working steam fluid instead of water. Except in midsummer at very low latitudes, the absorbed solar heat cannot boil water, which boils at 100 degrees C.
However, CT (a common non-toxic dry cleaning chemical) boils at 79 degrees C. The heat stored in the water can easily boil CT, and keep it boiling from two to six hours past sundown, given enough water mass. This can obviate the need for fuel entirely, or further reduce its use by another 1/4 to 1/5 over the initial 1/4 to /15 reduction, making the total fuel savings 1/8 to 1/10 what had originally been required.
Many oil well owners might easily choose just to have the pump shut down for two to 6 hours a night, and never spend a single dime on fuel, using pure passive solar power to pump the oil. The CT method allows for this: straight water does not.
There is no better choice for an alternate working fluid, by the way.
I researched every chemical known to man, going through each and every
one, reading the Merck Chemical Manual (the chemist's bible) from cover
to cover, examining thousands of chemicals, looking for the best alternative
to water. Although some chemicals had appreciably lower boiling points,
these were either toxic, explosive when exposed to water or air, or degenerated
/ decomposed over time. (See: 1986 geothermal power plant
design) CT is also inexpensive in the small quantities required.