Zero Emissions Power Generation Boiler

Abstract

This is a zero emissions power generation boiler that can be used to drive a wide range of steam turbines, from 20 MW up to 1200 MW, creating dry steam pressure ranging from 1000 psi up to 4500 psi. It creates steam by burning liquid hydrogen with liquid oxygen, completely eliminating the emission of greenhouse gases, lethal poisons, and every form of pollutant. It employs high-pressure cryogenic fuel pumps, a water cooling system, an electronic sparking system, a double-wall cylindrical boiler with a hemispherical top, and a control system that employs electronic sensors, actuators, signal conditions, microprocessors, digital interfaces, and mechanical back-up systems. It can be used in new power plants or as a replacement for current boilers in existing power plants. It has the option of working as part of a combined cycle system and can employ steam reheat systems.

Claims

1. First claim: This zero [harmful] emissions power plant boiler is a unique design that can produce enough steam to run turbines ranging from 20 MW to 1200 MW, at pressures of 1000-4500 psi, by means of burning liquid hydrogen and liquid oxygen, completely eliminating the emission of greenhouse gases, lethal poisons, and all known pollutants, in a system comprising: cryogenic fuel tanks high-pressure cryogenic fuel pumps rings of centrally-located burners an electronic sparking system.

2. Second claim: The boiler is a unique, double-walled cylindrical design with a hemispherical top capable of handling the high stresses involved, in which steam pressure is created in the central cavity, rather than in a system of piping along the sides, and is comprised of: an outer wall an inner wall a steam header at the top.

3. Third claim: The boiler is cooled by a system of water pumps that send heated water at high pressure to rings of nozzles located between the burners and the walls, sending the water up into the central cavity where it becomes steam while cooling the walls and top of the boiler, in a system comprised of: cooling ponds a water holding tank a water pre-heat system high-pressure reciprocating water pumps rings of nozzles at the base of the boiler

4. Fourth claim: The boiler system is controlled by a large series of sensors, actuators, signal conditioners, microprocessors, and digital interfaces that allow feedback loops run through the plant control room to continually monitor and adjust cryogenic fuel temperature, pressure, and flow rate, cryogenic pump speed, electronic sparking system activation, water temperature and pressure, water pump speed, boiler steam temperature and pressure, boiler material stresses, and the temperature, pressure, and flow rate of the steam turbine intake, while being subject to manual and mechanical back-up systems, safety systems, and control overrides.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0020] There are eight drawings in this submission, two perspectives, one cutaway perspective section, one plan, and four elevations.

[0021] FIG. 1: Front Perspective

[0022] This is a perspective rendering with a view from the upper right rear of the project. It shows the general layout of the boiler, the steam turbine and generator, the water pumps, and the cryogenic fuel pumps, plus the upper part of the water preheat system. The drawing does not show power plant roofs and walls, the fuel holding tanks, the water holding tank, the water cooling ponds, the turbine steam outlets, the condenser, or the stack as these are not a part of the current application. The steam turbine and generator are shown because the connections and reheat system are a part of this application. The turbine shown is based on a Siemens steam turbine design, and its design is not a part of this application.

[0023] FIG. 2: Rear Perspective

[0024] This is a perspective rendering with a view from the upper left front of the project, showing the back end of the generator, turbine, reheat system, steam header, and boiler. It should be noted that the water pumps shown in these views are a reciprocating design based on pumps sold by GD Energy Products, their Thunder 5,000 HP Quintuplex model, and their design is not a part of this application.

[0025] FIG. 3: Perspective Cutaway Section

[0026] This is a cutaway perspective section with a view from the upper right rear side of the project. The outer casing of the boiler is cut away showing the double shell with a thinner outer shell and thicker inner shell, air-cooled from the outside. It shows a preliminary design for the upper part of the water pre-heat system (the lower part, not shown, is a customer option, either a combined cycle system or a stand-alone heat exchanger system). Inside the boiler walls are the water cooling system (outer rows of inlets) and the sparking and burner system (inner rows of electrical units and fuel injectors).

[0027] FIG. 4: Plan

[0028] The plan view is a bird's eye view of the project, showing the general layout of the boiler, pumps, and steam turbine. The inner ring of pumps are alternating high pressure liquid hydrogen and liquid oxygen pumps of a multi-stage design powered by electric motors. These will have to be a custom design for this project.

[0029] FIG. 5: Right Elevation

[0030] This elevation view shows the project from the right side. The boiler, steam header, and steam turbine can be clearly seen.

[0031] FIG. 6: Rear Elevation

[0032] This elevation view shows the project from the rear. The upper part of the water preheat system can be seen in front of the boiler.

[0033] FIG. 7: Left Elevation

[0034] This elevation view shows the project from the left.

[0035] FIG. 8: Front Elevation

[0036] This elevation view shows the project from the front.

DETAILED DESCRIPTION OF THE INVENTION

[0037] This zero [harmful] emissions power generation boiler is being designed as a potential replacement for power plant boilers all over the world that drive steam turbines by boiling water using nuclear fission or the combustion of coal, natural gas, fuel oil, biomass, and garbage. The idea is to replace all of the harmful emissions and by-products of those systems, including greenhouse gases like carbon dioxide, methane, and nitrous oxide; poisons like radioactive waste, small particulate matter, carbon monoxide, hydrogen sulfide, large particulate matter, volatile organic compounds, and carbon black; and known pollutants like nitrogen dioxide, sulfur dioxide, unburned and partially burned hydrocarbons, coal ash, spent nuclear fuel rods, and unburned waste with emissions that are nothing but water, water vapor, steam, oxygen, and hydrogen, the latter two pure atmospheric gases. The idea is to take the current deadly mix, responsible for around 10-50% of the world's air pollution and greenhouse gas emissions today, depending on the nation involved, a mix which plays a part in millions of fatalities worldwide every year, and replace it with a system whose emissions are completely harmless to humans, plants, and animals.

[0038] This can be accomplished by this design in a manner that does not decrease, in any way, the potential power or efficiency of modern power plants. In doing so it can totally eliminate the massively expensive and space-consuming scrubbers and emissions control equipment that today can cost more than the entire thermal energy plant they are designed around, and replace immensely expensive and often quite dangerous nuclear power plants near highly populated areas.

[0039] Today the world is witnessing a quiet revolution in energy production, in which green hydrogen and its companion product, oxygen, are starting to replace traditional fossil fuels, biomass, and garbage as combustibles. The price of those two fuels is now beginning to come down to a level that can make their use competitive with their rivals. Fuel costs are often fifty percent of the running costs of a typical power plant. The day is dawning, as natural gas and fuel oil prices skyrocket this year, as highly-polluting brown coal [lignite] is the only form of coal utility companies can afford to burn any more, as biomass and garbage are starting to be recognized for the dangerous polluters that they really are in practice; and as nuclear plants continue to get more and more expensive, when plants that burn hydrogen and oxygen to produce power will become competitive, not just in terms of initial construction costs, but also in terms of yearly miming costs and longevity, with their dirty and deadly emissions rivals in that market.

[0040] This zero emissions boiler is a different kind of power plant boiler system. First off, it burns two cryogenic fuels, liquid hydrogen and liquid oxygen, pumped to burners at its base by high-pressure multi-stage cryogenic fuel pumps at high pressure, to produce the steam. The fuels are lit by high-powered sparking systems between each pair of fuel injectors which can automatically deploy repeatedly if for some reason the flame from those injectors dies out. The fuels themselves are atomized by the injector heads to make mixing and ignition easier, but at the massive volumes required by modern power plants.

[0041] This process produces both high temperatures and high pressures. Liquid hydrogen and liquid oxygen burn with a fairly hot flame and can create as much steam pressure as the boiler walls and fuel injection pressure will allow. Modern steam turbines operate over a range of pressures, from around 1000 psi all the way up to around 4500 psi. This boiler design can work at any pressure in that range and can go all the way up to the maximum if the boiler walls and fuel pumps are built to handle the high tensile stress and pressure.

[0042] While the burners are in the middle of the boiler, at the bottom, and are placed some distance from the outside wall, with continuous use the radiant and convective heat from the flame will eventually create issues in that wall. There are, at this time, two different methods of cooling the boiler to prevent issues. The first, and more expensive method, is to increase the percentage of oxygen in the mix, which will cool the flame and shorten its length. The second one, envisioned as the everyday method in this instance, is pumping water, pre-heated to about 205-210 degrees F., at extremely high pressure into the boiler through a fairly wide ring of nozzles set in between the flame and the wall. The water, aimed at the walls and at the top of the boiler, will keep those walls cooled down to a temperature that will obviate thermal expansion and creep issues, and will also cool down the steam to a planned 1000-1150 degrees Fahrenheit, the so-called “dry steam” employed by modern steam turbines to lower corrosion and wear and tear on their blades and rotors. The cooling water, turning to steam itself at that temperature, will itself create even more steam pressure in the boiler.

[0043] Once the desired steam pressure and temperature have been achieved, the valve to the steam header at the top of the boiler will open up and supply steam to the turbine, causing its rotors and shaft to spin and turn the generator rotor, creating electrical current for the power plant. The design is planned to be practically self-regulating, with pump speeds continually adjusted by the plant control center to achieve the best possible steam temperature and pressure and optimal turbine rotor speeds.

[0044] This boiler design can accommodate either no steam re-heat, single steam re-heat, or double steam re-heat systems, depending on the turbine types used in the plant and the desires of the customer. The drawings submitted show a single steam re-heat system. It can work with a wide range of steam turbines, from about 20 megawatts (a small boiler) all the way up to about 1200 megawatts (the size of boiler shown in the submitted drawings). It can produce up to and above 10 million pounds of steam per hour. It can work as a single unit or as part of a large multi-unit power plant. It can be run as a stand-alone unit, powered by a dedicated heat exchanger in the water pre-heat system, or as part of a combined cycle plant, in which the water pre-heat system is powered by the hot exhaust from a combustion turbine sent through a heat exchanger system. The pre-heat system can also use passes through the boiler in pipes, in part, as shown in the submitted drawings, powered by water pumps. This system is also designed to be practically self-regulating and controlled by the power plant control room.

[0045] The water used to supply the cooling system is produced in a condenser (not shown in the drawings) at the far end of the generator and supplies cooling ponds (not shown in the drawings) adjacent to the boiler. These are not a part of this patent application and their design is a discretionary one for the customers.

[0046] The cryogenic fuel tanks include the main tanks (not shown in the drawings) and holding tanks (not shown in the drawings), hopefully equipped with pressure relief valves, cryogenic valves, booster pumps, cooling systems, boil-off re-liquefaction systems, phase control systems, and purging systems, but the size and style of these tanks is a discretionary one, based on customer design, the size of the turbines and plants, cost, fuel supplies, and other considerations, and they are not a part of this patent application.

[0047] The high-pressure water pumps shown in the drawings are based on a reciprocating five-cylinder design of GD Energy Products capable of producing up to 20,000 psi, and only their layout, not their design, is a part of this patent application.

[0048] The high-pressure cryogenic fuel pumps shown in the drawings will have to be a custom multi-stage design built to handle cryogenic fuels and the particular issues involved with pumping liquid hydrogen at these pressures. However, many successful high-pressure liquid oxygen and liquid hydrogen pumps have been designed in the past and there are companies that specialize in jobs like that. Their actual design, including lubrication design, stage design, and electrical motor design, are a bit below the scale of this patent submission and await further refinement, but their arrangement, shown in the drawings, is a part of this patent application.

[0049] The design of the high pressure fuel injectors and their sparking systems are also a bit below the scale of this patent submission, but their arrangement, shown in the cutaway perspective section drawing, is definitely a part of this patent application. The same goes for the outer rings of water nozzles shown in that drawing, their arrangement is definitely part of this patent application, but their design is a bit below its present scale and await further refinement.

[0050] The boiler pass-through piping of the water pre-heat and re-heat systems is shown in the drawings, but these are optional features in this design and up to the customers. The pre-heat pass-through pipes can be located at either the top or the bottom of the boiler, depending upon customer preference.

[0051] The cylindrical boiler wall and hemispherical roof design shown in the drawings are definitely a part of this patent application. This is a double-wall boiler, with the inner wall designed to handle all of the pressure inside the boiler and the outer wall with a thinner section, perforated for air cooling, designed to reinforce the inner wall and close up the gaps to prevent pressure leaks. The walls are designed in sections, joined by nuts, bolts, gaskets, O-rings, and sealants. The inner wall sections have large flanges for use in those connections and for reinforcement. The material of the inner wall will have to be able to handle a very wide range of temperatures and pressures, rust issues, oxidation issues, and hydrogen embrittlement issues and will probably end up being a high-strength nickel alloy of some kind. The outer wall may be a high-strength nickel or stainless steel alloy. These walls will technically be designed for a life of around 40 years or so without failure and so creep and repeated expansion and contraction will be critical issues in their design. The boiler may have to be periodically shut down for inspection, maintenance, and cleaning.

[0052] The steam header shown is a relatively standard design in modern power plants. There are no foreseeable variations in this design. The connections to the steam turbine vary with turbine design and are therefore not a part of this patent application.

[0053] This zero emissions boiler is designed to work in conjunction with a modern power plant control room and its display, monitoring, and actuating systems. These control rooms are designed by companies that specialize in that trade and the control room layout is not a part of this patent application, The sensors and actuators in this boiler are run through dedicated signal conditions, microprocessors, and digital interfaces that allow them to function in coordination with the plant control room.

[0054] There are many aspects of this boiler design that are controlled automatically, and many that may be subject to manual control at times. The temperature and pressure in the main fuel tanks and fuel holding tanks are designed as an automatic process, with feedback loops from the sensors controlling the cooling and re-liquefaction systems in those tanks. This is particularly important for the liquid hydrogen, which has to be contained within a very specific temperature and pressure range, and in a very specific phase, in order to lessen multi-phase flow, slush, cavitation, and dangerous vaporization in the lines and pumps. This issue becomes less important at higher pressures after it reaches the main fuel pumps, however. In addition, this system will be augmented by manual control overrides and mechanical pressure relief valves.

[0055] The water pre-heat system will also be controlled automatically, with temperature and pressure sensors working in feedback loops in conjunction with the heat exchanger and the water pumps, and will also be equipped with manual overrides where possible. The feedback loops controlling the pumps will also include strain gauges placed in the boiler walls. The two systems, including the main fuel pumps and the water pumps, will also have a feedback system that includes boiler temperature and pressure gauges and data from the turbine and generator related to their speed and power output. The fuel sparking system will also be automatic, adjusted by temperature, pressure, and flow sensors in the fuel lines and burners. The system will also be equipped with manual overrides and sensor, actuator, valve, and pump failure monitoring and protection.

[0056] So that is the sense in which this is being designed as an automatic system. Today sophisticated digital control systems can make adjustments in actuators hundreds of times per minute, and actually per second in some cases. They are just a lot faster and more accurate than human reactions, as a rule, and thus can save utility companies a lot of money and prevent excessive down time. However, they do fail occasionally, thus the need for manual overrides and some mechanical back-up and safety features.

[0057] There are certain safety issues in this design, including excessive pressure and flow blockages in the tanks, pipes, valves, and pumps, excessive pressure and temperature in the boiler and turbine, and hydrogen and oxygen leakage, that have to be addressed by safety features like mechanical pressure relief valves, emergency shut-downs, and hydrogen and oxygen monitoring equipment, but these things have all been done before successfully.