US20100028241A1

US20100028241A1 - Hydrogen Production and Carbon Sequestration in Coal and Natural Gas-Burning Power Plants

Info

Publication number: US20100028241A1
Application number: US12/552,898
Authority: US
Inventors: Surendra Saxena
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-10-25
Filing date: 2009-09-02
Publication date: 2010-02-04
Also published as: US20090202413A1; US8012453B2

Abstract

This invention describes a system of reactions for a partial sequestration of carbon (CO₂and CO) from coal burning plants and zero emission production of hydrogen and hydrides. The only raw material to be used is salt (sodium chloride, NaCl), coal and water or a metal for the hydride. Sodium hydroxide (NaOH) generated from the chloride is used for locking carbon dioxide in sodium carbonate and bicarbonate.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority under 119(e) to the provisional application entitled “Carbon sequestration and production of hydrogen and hydride” U.S. Ser. No. 60/982,473, filed Oct. 25, 2007, and this application is a continuation-in-part of international application PCT/US08/55586, claiming priority under 35 USC 120 to filing date 2 Mar. 2008.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO A SEQUENCE LISTING

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal government funds were used in researching or developing this invention.

BACKGROUND

1. Field of the Invention
This invention relates to a system of processes for sequestering carbon in coal-burning power plant and producing hydrogen gas that take advantage of emission of CO and CO₂and heat from the plants. The use of this invention will lead to cheap hydrogen and hydride production and carbon sequestration and reduced global warming.
2. Background of the Invention
The United States leads the world in per capita CO₂-emissions. In 2004, the total carbon release in North America was 1.82 billion tons. World-wide industrial nations were responsible for 3790 million metric tons of CO₂(Kyoto-Related Fossil-fuel totals). There is little doubt that the world is choking with greenhouse gases.
No one can deny that there is an urgent need to develop innovative solutions to reduce the emissions from our automobiles and from our coal or gas burning power plants. This invention may well provide an answer to the problem of greenhouse gas emissions and pave the way towards a clean energy future. The invention addresses carbon sequestration in coal or gas burning plants used for power generation or for manufacturing (cement, steel etc.). The chemical process that sequesters carbon gases (thus preventing them from escaping to the atmosphere) generates hydrogen as a byproduct.
Coal burning power plants currently produce electricity to satisfy the needs of a power hungry economy all over the world and in doing so also produce much of the greenhouse gases. While coal is used to generate electric power, it is also used for producing hydrogen by reaction with water. Therefore, its continued use would be of immense help to the world if only we can sequester the carbon. This invention helps to do exactly that and if we develop this technology, we could continue to use coal for many decades without any environmental degradation.
Currently steam methane reforming is the most common and the least expensive method to produce hydrogen [1]. Coal can also be reformed to produce hydrogen through gasification. Hydrogen production by methods that do not emit CO₂are either more expensive compared to those using fossil fuels or are in the very early stages of development [2-4]. Since the United States has more proven coal reserves than any other country, hydrogen production through a coal-based technology is a very attractive prospect. However, effective and low cost carbon sequestration technology has not yet been developed.
Hydrogen is widely regarded as the energy of the future, but to produce and use hydrogen—either by direct combustion or in a fuel cell—it is necessary to use other sources of energy. Thus using hydrogen or any other material to produce energy cannot be environmentally clean and economically viable unless the process by which it's produced sequesters carbon or is otherwise free of greenhouse gas emissions. The use of hydrogen is being promoted on a federal level with financial support, and we may eventually have hydrogen-using technology for our transportation and other energy needs. However, it is a sad fact that the production of the hydrogen to be used in that technology will most likely continue to be dependent on the use of fossil fuels for the foreseeable future, and it may not be viable either economically or environmentally. Solving this problem requires alternative methods of using coal to produce hydrogen and hydrides. Many hydrides are currently being considered for use in the on-board generation of hydrogen, and the cost of producing the hydride is an obviously critical factor in this evaluation. This project would use carbon to produce hydrogen with carbon sequestration.

Coal-Burning Power-Plants are Harmful to the Environment

Coal is used extensively in producing synthetic fuels [1]. Use of coal in gasifiers is well established and hydrogen may be produced by the reaction: C+2H₂O=CO₂+2H₂. Gasifiers are operated between 500 to 1200° C., and use steam, oxygen and/or air and produce a mixture of CO₂₂, CO, SO₂, NO_x, H₂, CH₄and water. Treatment systems are available for SO2 and NO_xbut CO₂₂remains a problem. The CO produced can be further processed by the shift-gas reaction to produce H₂with production of CO₂: CO+H₂O=CO₂+H₂. The following is an extract from a report by National Academy of Engineering, Board on Energy and Environmental Systems [5] and shows the importance of the present study: “At the present time, global crude hydrogen production relies almost exclusively on processes that extract hydrogen from fossil fuel feedstock. It is not current practice to capture and store the by-product CO₂that results from the production of hydrogen from these feed stocks. Consequently, more than 100 Mt C/yr are vented to the atmosphere as part of the global production of roughly 38 Mt of hydrogen per year.”
It would then appear that when coal is used in gasifiers or in direct burning in power- and other manufacturing-plants, CO₂and CO are prominent among other gases released to atmosphere. Their emission is not only harming the environment but as considered here is also a waste of resources. For industry this has been an economic issue.
This invention provides a clear economic incentive to sequester carbon (CO₂and CO) without significantly affecting our current modes of operations i.e. the coal-burning power plants. It will also show that hydrogen will be produced at much lower costs and with zero emission of greenhouse gases.
Many new coal-burning power plants are now in the offing. This is the right time to act.
Related patents include the following.
U.S. Pat. No. 7,132,090, D. Dziedzic, K. B. Gross, R. A. Gorski, J. T. Johnson, Sequestration of carbon dioxide.
US patent application 20030017088, W. Downs and H. Sarv Method for simultaneous removal and sequestration of CO₂in a highly efficient manner.
US patent application 20010022952, G. H. Rau and K. G. Caldeira Method and apparatus for extracting and sequestration carbon dioxide
U.S. Pat. No. 5,261,490, T. Ebinuma Method for dumping and disposing of carbon dioxide gas and apparatus therefore.
U.S. Pat. No. 6,667,171, D. J. Bayless, M. L. Vis-Morgan and G. G. Kremer Enhanced practical photosynthetic CO2 mitigation.
U.S. Pat. No. 6,598,407, O. R. West, C. Tsouris and L. Liang Method and apparatus for efficient injection of CO₂in ocean.
U.S. Pat. No. 5,562,891, D. F. Spencer and W. J. North Method for the production of carbon dioxide hydrates.
U.S. Pat. No. 5,293,751, A. Koetsu Method and system for throwing carbon dioxide into the deep sea.
U.S. Pat. No. 6,270,731, S. Kato, H. Oshima and M. Oota Carbon dioxide fixation system.
U.S. Pat. No. 5,767,165, M. Steinberg and Y. Dong Method for converting natural gas and carbon monoxide to methanol and reducing CO₂emission.
U.S. Pat. No. 6,987,134, R. Gagnon How to convert carbon dioxide into synthetic hydrocarbon through a process of catalytic hydrogenation called CO₂hydrocarbonation.
U.S. Pat. No. 7,282,189 B2 Zauderer Production of hydrogen and removal and sequestration of carbon dioxide from coal-fired furnaces and boilers.
U.S. Pat. No. 2006/0048517 A1 Fradette et al. Process and a plant for recycling carbob dioxide emissions from power plants into useful carbonated species.
U.S. Pat. No. 2004/0126293 Geerlings et al. Process for removal of carbon dioxide from flue gases.
U.S. Pat. No. 6,669,917 B2 Lyon Process for converting coal into fuel cell quality hudyrogen and sequestration-ready carbon dioxide.
U.S. Pat. No. 7,083,658 B2 Andrus Jr. et al. Hot solids gasifier with CO₂₂removal and hydrogen production.
U.S. Pat. No. 2006/0185985 A1 Jones Removing, carbon dioxide from waste streams through co-generation of carbonate and/or bicarbonate minerals.

SUMMARY OF THE INVENTION

The present invention provides a system of reactions to sequester carbon and produce hydrogen from sodium hydroxide and CO or CO₂and carbon or natural gas. The carbon gases are produced in industrial plants burning coal and thus available at no cost. These gases also can be obtained at relatively high temperature; the reaction of CO or CO₂and carbon with sodium hydroxide is exothermic and hence no additional heating may be required. The CO or carbon or natural gas and CO₂would react to form sodium carbonate and thus carbon will be sequestered. The main points are: We continue to use coal burning power plants for electric generation and other uses; The emitted gases mostly CO and CO₂(the green-house gases causing global warming) at modest temperatures and hydroxide are fed into chemical reactors built adjacent to the power plant; Chemical reactions between gases and hydroxide and carbon or natural gas produce solid carbonate and hydrogen; The reactant NaOH is produced preferably with a non-fossil energy source (nuclear, hydro-, solar- or wind-) and the products carbonate and hydrogen are sold reducing the cost of the power plant and generating electricity; Electric or thermal power is produced from coal-burning plants with zero emission of greenhouse gases, and Hydrogen is produced economically with zero emission because of the low materials cost and low energy cost due to use of hot gases; use of hydrogen in transport will further reduce CO₂-emission.
An embodiment of the present invention provides for a complete sequestration of carbon and hydrogen production using CO from coal-burning power plant. In such a case, sodium hydroxide reacts with CO producing hydrogen and carbonate and no carbon is released in the environment.
Another embodiment of the present invention provides the production of carbonate and hydrogen using CO₂from coal-burning power plant and reacted with carbon and sodium hydroxide. In such a case, sodium hydroxide reacts with carbon and CO₂producing hydrogen and carbonate and no carbon is released in the environment.
Another embodiment of the present invention provides the production of carbonate and hydrogen using CO₂or CO or any mixture thereof from coal-burning power plant and reacted with natural gas, water and sodium hydroxide. In such a case, sodium hydroxide reacts with water, natural gas and CO/CO₂producing hydrogen and carbonate and no carbon is released in the environment.
Another embodiment of the present invention provides the production of hydrogen if the industrial CO or CO₂is not available. In such a case, sodium hydroxide reacts with water and carbon or natural gas producing hydrogen and no carbon is released in the environment.
Another embodiment of the present invention provides for further sequestration of CO₂by reaction of the unsold Na₂CO3 with water and CO₂.
Another embodiment of the present invention provides for the existing coal-burning power plants to be retrofitted with the reactor design presented in FIG. 7 or any such design with better engineering attributes.
Finally, hydrogen produced in the reactor is used to produce hydrides, specifically magnesium hydride at a low cost,

Relation to Other Published Work and Patented Processes

The use of hydroxide in sequestering carbon from processes using fossil-fuel has been suggested in many publications and in some patents (Table 1). A technique to use the carbonation reaction for use with coal-burning power plants has been described by Jones (US 2006/0185985 A1) who uses the reaction:
NaOH+CO₂=Na₂CO₃(or bicarbonate)
The strategy adopted in this work differs in using several reactions that produce hydrogen as well as form the carbonate. Production of hydrogen with zero emission and using the carbonate gainfully are important aspects of the present invention. Unlike the reactions used in this invention, the Skyonic method relies on a single direct carbonation reaction. Others have used solids such as CaS (U.S. Pat. No. 7,083,658 B2 Andrus Jr. et al.) and CaO (U.S. Pat. No. 6,669,917 B2 Lyon) with different effects. Others use hydroxide reaction with CO₂involving CaO (Lin et al., 11, Xu et al.9), magnesium and calcium silicates (Zevenhoven et al, 10) and alkali hydroxide (Ishida et al. 8). Finally the ZECA (Zero Emission Coal Alliance) process uses Ca(OH)₂.

BRIEF DESCRIPTION OF THE DRAWINGS

The purpose of this invention and the tremendous advantages it entails for reduction in global warming gases needs to be fully understood from the study of the description along with the drawings herein.

FIGS. 1 and 2 show in two parts a comparison of the calculated equilibrium compositions, which are easily verified in experiments. FIG. 1 is a well known phase diagram showing the carbon-water system in a gasifier where hydrogen and CO mixture is produced up to very high temperatures.

FIG. 2 is a diagram and shows a comparison with the reaction adopted in the present invention to that shown in FIG. 1. The temperature of hydrogen production is much lowered and the gas is pure hydrogen.

FIG. 3 shows the moles of hydrogen and sodium carbonate produced when sodium hydroxide and carbon monoxide are allowed to react. The carbon monoxide is presumably generated in a coal-burning process providing heat to another manufacturing process, e.g. synthesis of cement.

FIG. 4 shows that in absence of an industrial source of carbon-oxygen gases, this invention provides for the production of hydrogen from water, carbon and sodium hydroxide reaction with no emission of C—O gases.

FIG. 5 shows the reaction where carbon may be replaced by methane with high production of hydrogen.

FIG. 6 shows an experimental setup that was used to produce the experimental results shown in the following figures. Equipment for the study of hydrogen generation is used with laser break-down spectroscopy to measure the hydrogen formation.

FIG. 7 shows experimental data for the reaction (2NaOH(c)+C(c)+H₂O(1)=Na₂CO₃(c)+2H₂). The temperature was increased at a rate of 4° C./min starting from 110° C. to reach a maximum of 700° C. in about 150 minutes.

FIG. 8 shows Hydrogen generation in 2NaOH+C+H₂O→Na₂CO₃+2H₂reaction studied at different temperatures. N₂carrier gas flow rate 50 mL/min.

FIG. 9 shows Experimental data for the reaction (2NaOH(c)+CO(g)=Na₂CO₃(c)+H₂(g)). Temperature was increased at rate of 4° C./min. Two different rates of flow of CO were used. Lower hydrogen yield for higher CO flow could be explained if one takes into account CO disproportionation reaction 2CO→CO₂+C, the rate of which depends on the CO partial pressure. Released CO₂will react with sodium hydroxide decreasing amount of the latter available for the reaction with carbon monoxide.

FIG. 10 shows Hydrogen generation in 2NaOH(c)+CO(g)=Na₂CO₃(c)+H₂(g) reaction studied at different temperatures. N₂carrier gas flow rate 50 mL/min. 90% hydrogen resulted in less than 60 minutes.

FIG. 11 shows Hydrogen flow rates in the CO+2NaOH reaction measured at different temperatures and CO flow rate of 20 mL/min and N₂flow rate of 50 mL/min. Hydrogen flow rate vs. time dependence at 300° C. is characterized by quite long (about 3 h) initialization period. However, after 3 h the reaction accelerated in a tubular furnace with a quartz tube. Nitrogen gas with a flow rate of 50 ml/min was used as a carrier to deliver steam to the reactor.

FIG. 12 shows a not-to-scale schematic diagram showing a possible industrial set up of a reactor to be linked to a coal-burning power plant and a sodium hydroxide production plant. The power plant provides hot CO or CO₂to the reactor. NaOH delivered to the reactor is advanced through the length of the reactor by a screw feeder over the required time period for reaction which could be usually 60 minutes. Since the reaction is highly exothermic, power must be adjusted by monitoring the temperature by use of a thermocouple. Maintaining the temperature at 400° C. would ensure the result. It is permitted for CO pressure to be built up to some bars and for the newly formed hydrogen to exit through a membrane and be collected for use. The screw feeder delivers the finished product Na₂CO₃and may be some unused CO and H₂mixture to a container. The gases from the container may be reused as necessary. This design will also apply to Process IV reactions where carbon is replaced by methane. Additional sequestration of CO₂is possible through the reaction of Na₂CO₃, water and CO₂. The product sodium bicarbonate could then be sold or used in landfills.

FIG. 13 shows a not-to-scale schematic diagram showing a possible industrial set up of a reactor to be linked to a coal-burning power plant and a sodium hydroxide production plant. The power plant provides electric power for the latter as well as hot CO₂to the reactor. NaOH is delivered to the reactor at the top and CO₂and if needed for reaction (5) the natural gas from the bottom. This is a closed system reactor. The required time period for reaction could be usually 180 minutes. Since the reaction is highly exothermic, power must be adjusted by monitoring the temperature by use of a thermocouple. Maintaining the temperature at 700° C. would ensure the result. It is permitted for CO₂pressure to be built up to some bars. The newly formed hydrogen exits through a membrane and is collected for use. After the reaction is complete with no hydrogen flowing out, the reactor can be emptied into another container. The finished product would be Na₂CO₃and some unused CO₂. This design will also apply to Process IV reactions where carbon is replaced by methane. Additional sequestration of CO₂is possible through the reaction of Na₂CO₃, water and CO₂. The product sodium bicarbonate could then be sold or used in landfills.

FIG. 14 shows a not-to-scale illustration of a screw reactor sketched in FIG. 12. The reactor could be used for both CO and CO₂and if needed for reaction (5) the natural gas with different times and temperatures as required.

FIG. 15 shows a schematic diagram for the flow of materials using a conveyor belt design. The sodium carbonate may further be used by using Process V to sequester additional CO₂, which may be accomplished by passing the gas through series of tanks with water and the carbonate until all gas is adsorbed.

FIG. 16 shows the cost calculations for carbon sequestration assuming that Na₂CO₃sells for $100 per ton and production cost for NaOH varies from $100 per ton to $200 per ton. This calculation applies to the first several power-plants which use this technique. As the Na₂CO₃supply continues to rise, the price structure would change. $2000/ton price of hydrogen is used for carbon sequestration calculation. (See Tables 2 and 3 for detailed calculation).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a novel method of sequestering carbon producing hydrogen with carbon sequestration; the novelty lies in the fact that gases produced in a coal-burning plant are used both for the energy and for the substance to react with sodium hydroxide reducing the cost simultaneously with eliminating the emission. The invention relies on processes described below.

Process I. CO₂Sequestration and Hydrogen Production

For existing power stations, where CO₂is produced, we may choose this alternative and use CO₂to react with water and Sodium hydroxide according to the reaction:
4NaOH(c)+C(c)+CO₂(g)=2Na₂CO₃(c)+2H₂(g)ΔH=−6.62 E4(600 K) (1)
One may compare this reaction with the combination of the gasifier reaction C+2H₂O=CO₂+2H₂and the CO₂absorbing reaction 2NaOH+CO₂=Na₂CO₃+H₂O to accomplish similar result. It is shown in FIG. 1 and FIG. 2 that the reaction (1) has definite advantage as the carbon-sequester and hydrogen producing reaction. A comparison of the two figures shows that much higher temperature is required to obtain a significant amount of hydrogen mixed with CO in FIG. 1 than is required when using reaction (1) (FIG. 2). Reaction (1) can be considered as a combination of the Boudouard reaction:
C+CO₂=2CO
and reaction (1). Reaction (2) may also be considered as a combination of
2NaOH+CO₂=Na₂CO₃+H₂O and
2NaOH+C+H₂O=Na₂CO₃+2H₂

Process II. CO Sequestration and Hydrogen Production

CO is not produced in coal burning because high ratio of air to coal is used. However if the heating requirement for the plant is fully met with a lower ratio such that CO is actually produced in some quantity, we could use the CO for producing hydrogen according to the following reaction
2NaOH(c)+CO(g)=Na₂CO₃(c)+H₂(g)ΔH=−119E5 J (600 K) (2)
An equilibrium calculation in FIG. 3 shows that Na₂CO₃also known as soda ash and hydrogen are produced over a wide temperature range starting from 400 to 1100 K. However, if we switch to coal-burning plant design that produces significant CO, we will have to burn more coal for the same thermal effect as can be seen by calculating at 1000 K
C+Air(N ₂4,O ₂1 mole)=CO2, ΔH=−2.746E5 J
C+Air(N ₂2, O₂0.5 mole)=0.763CO+0.118 CO₂+0.12C, ΔH=−6.628E4 J
Process III. Hydrogen Production with Zero Emission
We may consider reaction (3), if CO or CO₂₂are not available from an industrial plant:
2NaOH(c)+C(c)+H₂O(l)=Na₂CO₃(c)+2H₂(g)ΔH=6.458 E4 (600 K)
Reaction (3) was proposed by Saxena [6]. While this is an endothermic reaction, less amount of solids are required to produce the same amount of hydrogen. This may be helpful if the cost structure of the sodium compound alters in time. In this process 20 kg of NaOH will yield 26.5 kg of Na₂CO₃for each 1 kg of hydrogen. FIG. 4 shows the calculated phase diagram.
It is possible to consider a combination of the reactions. For example, reactions (1) and (3) or (1) and (2) may be combined respectively as follows:
6NaOH+CO₂+2C+H₂O=3Na₂CO₃+3H₂, (3a) and
6NaOH+(1−x)CO₂ +xCO+C=3Na₂CO₃+3H₂. (3b)
Combination of the reactions may be optimized by taking into consideration the costs of the energy, products and reactants.

Process IV. Use of Natural Gas

We may also consider the use of cheaply available natural gas as follows:
2NaOH+CH₄+H₂O=Na₂CO₃+4H₂ (4)
for hydrogen production. For sequestration of carbon with hydrogen production, we use
4NaOH+CH₄+CO₂=2Na₂CO₃+4H₂ (5)
4NaOH+CH₄+CO+H₂O=2Na₂CO₃+5H₂ (6)
Several mixed reactions between (5) and (6) are feasible and may be optimized as before.

Process V. Treatment of Na₂CO₃and Additional Carbon Sequestration

The excess carbonate can be further used to sequester additional CO₂according to the reaction:
Na₂CO₃+CO₂+H₂O=2NaHCO₃ (7)
This reaction takes place at 25° C. and does not require heating.

Process VI. Synthesis of Hydrides Using the Hydrogen

Hydrogen formed in the above procedure may be directly used for synthesizing hydrides. A hydride which may be synthesized at the site is Mg+H₂=MgH2. This reaction is exothermic (DH=−76 KJ/mol) and with a well ground metal would proceed rapidly to completion.

Experimental Data

Experiments were conducted to verify the theoretical predictions for reactions (2) and (3) using an in-house method involving measurement of evolving hydrogen by break-down laser spectroscopy (FIG. 6). The reaction between carbon, sodium hydroxide (anhydrous sodium hydroxide, supplied by Alfa Aesar (97%)) and water was carried out in a gas-flow system (FIG. 6). Sodium hydroxide was dissolved using a minimal amount of distilled water in an alumina boat and then activated carbon was immersed into this solution. The alumina crucible was put in the quartz tube as shown in FIG. 6.
The reaction between NaOH and CO was studied using the same experimental setup. Both reactions were first explored with temperature increasing at a fixed rate, reaction (3) between 110 to 700° C. (FIGS. 7 and 8) and reaction (2) between 110-400° C., (FIG. 9). Reaction (3) was studied at two different flow rates of CO (10 and 20 ml/min) (FIG. 9). Both reactions were complete in less than 200 minutes. Results of isothermal kinetic experiments at several temperatures are shown in FIG. 10 (reaction 2) and 8 (reaction 3). Hydrogen concentration in the effluent gases from the reactor was determined by laser beak-down spectroscopy. Before analysis the gases were passed through liquid nitrogen (NaOH/C/H₂O reaction) or acetone/dry-ice (NaOH/CO reaction) cooled condenser to remove all hydrogen containing species except for H₂gas.
Design of an Integrated Plant for Power and Hydrogen Generation with Zero Emission
The only raw material required is coal (or natural gas), sodium chloride and water. To minimize the costs it is essential that an integrated design of the plant is used. It should consist of:

- 1. A plant to produce sodium hydroxide (NaOH) which uses the electricity preferably from an alternate-energy source(nuclear, hydro-, geothermal, solar or wind; however we note that since all electricity is sold from grids from all sources, this may not always be possible) (byproducts chlorine and hydrogen in this manufacturing process are sold reducing the production cost of NaOH),
- 2. A coal-burning or natural gas power plant that generates power for electricity or power for manufacturing materials and from which off-peak power can be tapped for forming NaOH, and which gives off CO and CO₂,
- 3. A screw feed reactor (conveyor belt design is shown in FIG. 15) which takes the energy for heating from the coal-burning power plant and from the ensuing gases and permits the reaction between the hydroxide and the gases, and finally
- 4. A series of reactor tanks for Process V where CO₂is sequestered by bubbling it through a mixture of sodium carbonate and water.

We can consider the following type of situations. Although we deal with separate reactions below, in actual practice the composition of the feeder stock in the reactor will be determined by optimizing the desired yield of products using the several reactions. Such composition would be variable depending on the supply and demand of the products.

1.The Coal Burning Power Plant Produces Mostly CO

In such a case, we use the reaction (2) and reaction (6) as described under Process II and Process IV FIG. 12 shows a schematic diagram of the plant design. Stainless steel cylinder may be used with an alumina lining for protection from the corrosive reactants. The dimension of the vessel will have to depend on the size of the coal-burning power plant and the volume of the emitted gases. The reactor will be linked to the exhaust gases from the power plant and the plant for production of NaOH. Hot gases will be fed to the reactor vessel at one end and NaOH at the other end which is advanced by screw feeding mechanism. Temperature inside the reactor is maintained at 400 C. Since this is a highly exothermic reaction, the temperature must be monitored with a thermocouple and power adjusted accordingly. The kinetics of this reaction are such that one can expect the movement of the reactant solid to advance to the end of the vessel in one hour or more as needed for the completion of the reaction. Hydrogen is collected from the top. The electric power from the coal-burning power plant is used for powering the exothermic reaction and for consumers; the production of NaOH is preferably from an alternate non-fossil energy source such as hydro-, geothermal or nuclear.

2.The Coal-Burning Power Plant Produces Mostly CO₂

In such a case, we have to consider the reaction in a closed system for the reactions (2) and (5). The reaction (2)
4NaOH(c)+C(c)+CO₂(g)=2Na₂CO₃(c)+2H₂(g)ΔH=−6.62 E4 (600 K)
may be considered as a combination of
2NaOH+CO₂=Na₂CO₃+H₂O and
2NaOH+C+H₂O=Na₂CO₃+2H₂
Catalysis of the reactions was not employed in our experiments but if needed can be used as has been discussed in detail in literature [1]. A high production rate would result if the hydrogen is formed by continuous flow processes. As envisaged here, the equilibrium calculations are for a closed system with a complete conversion of fixed ratio of reactants and production of the carbonate and hydrogen. Catalysis and partial conversion of the reactants will affect the costs.
We use the steel reactor vessel whose dimension will depend on the size of the coal-burning plant (FIGS. 13 and 14). The vessel has access for the solid (NaOH+C) feeder at the top, and for CO₂at the bottom and for taking out the products; the vessel is otherwise sealed. As before the steel vessel is lined on the inside with alumina. After feeding the reactants, the temperature is raised to 700° C. at a rate of few degrees per minute. Since this is an exothermic reaction, the temperature inside the vessel must be monitored with a thermocouple and power adjusted accordingly. The reaction should be complete rapidly.
3. The Reaction to Produce Hydrogen with Zero-Emission
We may use the hot steam from the coal-burning plants and could use the same set up as shown in FIG. 12-14.

4.The Reactions in Process IV

We may also use natural gas in sequestering carbon and producing hydrogen according to Process IV reactions using the same plant design as shown in FIG. 12-14.

5.The Bicarbonation Reaction

CO₂is bubbled through several tanks with water and carbonate until all of it is absorbed. The size and number will depend on the size of the power plant.
6. Hydride Production
The evolving hydrogen may be fed into additional reactors with some pressure (2 atmospheres) with well stirred magnesium metal to form hydrogen. Since the reaction is exothermic no additional heating may be necessary.
Cost Analysis
The cost of NaOH in the market may fluctuate wildly depending on the supply and demand. The following calculations are based on an assumed cost of producing NaOH which may vary from $50 to $200 per ton and a selling price for Na₂CO₃. We note that if nuclear, hydro or geothermal energies are used, the price would be much less. Although examples of calculations are given here using separate reactions, in actual practice the composition of the feeder stock in the reactor will be determined by optimizing the desired yield of products using the several reactions. The production of NaOH (chloralkali process) may involve in simplified form a reaction such as
2Na+2H₂O+2e−=2NaOH+H₂
In industrial production which employs NaCl, there is formation of chlorine in addition to hydrogen. The energy consumption to produce 1 ton of Cl₂by electrolysis with diaphragm is around 2720 kWh. This gives us 2413 kWh per 1 ton of NaOH. To produce 1 ton of NaOH one needs 1.463 ton of NaCl. Chlorine (888 kg) and H₂(25 kg) are byproducts of the electrolysis. Thus the cost of 1 ton NaOH production is:
1.463×price of NaCl $/ton+(2413×Price of electricity $/kWh)−(0.888×price Cl₂$/ton)−(25×price H₂$/kg)
Cl₂price varies from $220 to $240 (http://www.the-innovation-group.com/ChemProfiles/Chlorine.htm). Rock Salt price is ca.$60(http://www.ct.gov/dot/lib/dot/documents/dsalt/winterops.pdf). Construction cost, labor, water etc., which are not included in this estimation, of course, will increase the price of NaOH as well as the supply and demand for chlorine. With price for Cl₂and NaCl $220 and $60, respectively and electricity cost of $0.09/kWh, the cost of 1 ton NaOH is quite small. However, it must be emphasized that this energy must not be obtained from burning coal, otherwise the CO₂₂production would continue to exceed all amounts that we can lock in Na₂CO₃. It may be possible for several reactors to operate using off-peak power.
For the reaction:
2NaOH+C+H₂O=Na₂CO₃+2H₂
The requirements are 80 kg of NaOH producing 106 kg of Na₂CO₃and 4 kg of hydrogen; to the latter we can add the already produced 2 kg of H produced while manufacturing NaOH (sale of chlorine should also be considered). Table 2 shows the material costs. To this we must add the energy costs as well as also consider that this is a zero emission product.
Reaction (3), however, is not useful (in terms of reducing greenhouse gases) for coal-burning power plants even though it is a zero-emission process. For coal-burning power plants, we use the reaction:
4NaOH+CO₂(or mixture of CO₂and CO)+C=2Na₂CO₃+2 H₂ (2)
The requirements are 160 kg of NaOH producing 212 kg of Na₂CO₃and 4 kg of hydrogen; to the latter we can add the already produced 4 kg of H produced while manufacturing NaOH as discussed above. The costs are shown in Table 1 for variously assumed cost of producing the reactant at the plant. To this we must add the energy costs, which will be much less than that for reaction (2) because we will be using hot gases from the power plant. Furthermore, the power plant will be used for generating thermal or electric power.
We may also consider the use of cheaply available natural gas as follows:
2NaOH+CH₄+H₂O=Na₂CO₃+4H₂
The requirements are 80 kg of NaOH and 16 kg of CH₄which produces 106 kg of Na₂CO₃and 8 kg of hydrogen; to the latter we can add the already produced 2 kg of H produced while manufacturing NaOH as discussed above. The cost of NaOH is (80×0.15=$12.0), the cost of CH₄based on ($0.04/kg) is ($0.16) selling price of Na₂CO₃is $10.6 resulting in $1.86 for 10 kg of hydrogen produced for less than $0.16 per kg. To this we must add the energy costs. A hybrid process (a combination of reactions), which uses hot gases from the power plant, may be possible and energy efficient. Any one reaction or combination of reactions may be employed, adapted to local conditions as appropriate. The cost calculations for the reactions with natural gas are shown in Table 2 and are certainly quite exciting.
FIG. 16 shows plot of calculated costs for carbon sequestration. It is demonstrated that for a range of values for sodium hydroxide, the material costs remain negative i.e. money is actually saved by sequestering carbon gases and producing hydrogen. Note that none of the other costs of manufacturing, such as infra-structure development, energy and labor, are included in the calculations. Finally what if the price structure changes in such a way that we must totally discard sodium carbonate (possibly by burying it in an environmentally safe way)? The material costs would vary from $1.2 to $3.0 per kg of hydrogen. Table 2 shows that for practically every reaction considered, there is a profit if carbon is sequestered. Considering that the hydrogen is produced with zero emissions—and lets us burn coal to generate electric and thermal power, also with zero emissions—this process has enormous beneficial consequences for the world.

Impurities in Coal and Other Exhaust Gases

The invention addresses principally the sequestration of carbon and production of hydrogen. The question of clean air involves minor and trace components of natural fossil-fuels e.g. sulfur, mercury, nitrous oxides etc. The removal of these has been researched very well and can be handled appropriately as needed by adding the necessary reagents to sodium hydroxide.
Tables 2 and 3 show various other models of price variation and the effect on the price of carbon sequestration.

Limitations

It is to be emphasized that the production of NaOH should be preferably done using electricity from a nuclear or other alternate source (byproducts chlorine and hydrogen in this manufacturing process are sold reducing the production cost of NaOH). If off-peak power is used to advantage, the processes would yield results no matter the source of power. It is possible to use the energy from the same plant but all CO₂emitted will not be sequestered; the advantage of hydrogen produced and used for applications that would otherwise emit CO₂should be considerd.
Reactions (1) to (7) used in this invention or the reaction described by Jones (US 2006/0185985 A1) and other carbonation reactions cannot sequester CO₂effectively if electric energy from coal-burning power plants is to be used for the production of NaOH. It can be easily demonstrated that several tons of CO₂has to be emitted in forming one ton of NaOH if fossil fuel is used. The current market price of NaOH and Na₂CO₃would permit several coal/natural gas burning power plants to operate with profit but as the products (Na₂CO₃, and Cl₂) saturate the market, additional power plants could be retrofitted if NaOH price can be brought down substantially by using alternate energy sources and off-peak power. It is all possible because the raw materials (NaCl and coal) are almost inexhaustible.
An alternative would be to consider only a 10% reduction in CO₂in a power plant 500 megawatt size. In such a situation we will produce about 1 to 1.5 million tons of solid material per year and it will be possible to manage the flow of material through the reactor.
The chlor-alkali process requires significant energy which must come from some source. If available, the energy can be used from the same power plant, which may amount to 30% of the total plant energy resulting in more CO₂emission than the process can sequester. However, since the energy if not used this way would have resulted in even more CO₂emission. By using this method, we reduce the CO₂by some percent (depending on the target, see [00108]) and produce hydrogen which will replace the energy from coal in a variety of applications. When hydrogen replaces gasoline in transportation, the overall effect of green-house-gas emission will be substantial.

REFERENCES

1. Probstein, R. F. and Hicks, R. E. Synthetic fuels, Dover, New York, 2006.
2. Gupta, H.; Mahesh, I.; Bartev, S.; Fan, L. S. Enhanced Hydrogen Production Integrated with CO ₂₂ Separation in a Single-Stage Reactor; DOE Contract No: DE-FC26-03NT41853, Department of Chemical and Biomolecular Engineering, Ohio State University: Columbus, Ohio, 2004.
3. Ziock, H-J.; Lackner, K. S.; Harrison, D. P. Zero Emission Coal Power, a New Concept. Proceedings of the First National Conference on Carbon Sequestration, Washington, D.C., May 15-17, 2001.
4. Rizeq, G.; West, J.; Frydman, A.; Subia, R.; Kumar, R.; Zamansky, V.; Loreth, H.; Stonawski, L.; Wiltowski, T.; Hippo, E.; Lalvani, S. Fuel-Flexible Gasification-Combustion Technology for Production of H ₂ and Sequestration-Ready CO ₂; Annual Technical Progress Report 2003, DOE Award No. DE-FC26-00FT40974. GE Global Research: Irvine, Calif., 2003.
5. “The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs (2004),)” Carbon Emissions Associated with Current Hydrogen Production: “National Academy of Engineering (NAE), Board on Energy and Environmental Systems (BEES).
6. Saxena, S. K. Drozd Vadym, Durygin Andriy, Synthesis of metal hydride from water. Int J. Hydrogen Energy 32 (2007) 2501-2503.
7. Saxena, S. K. (2003) Hydrogen production by chemically reacting species: International J. of Hydrogen Energy, 28,49-53.
8. Ishida, M., Toida, M., Shimizu, T., Takemaka, S., and Otsuka, K. Formation of hydrogen without CO_xfrom carbon, water, and alkai hydroxide. Ind. Eng. Chem. Res. 2004, 43, 7204-7206.
9. Xu, X., Xiao, Y and Qiao, C. System design and analysis of a direct hydrogen from coal system with CO₂capture. Energy and Fuels 2007, 1688-1694.
10. Zevenhoven, R. Eloneva, S., and Teir, S. Chemical fixation of CO2 in carbonates: Routes to valuable products and long-term storage. Catalysis Today 115, 2006, 73-79.
11. Lin, S., Harada, M., Suzuki, Y. and Hatano, H. Hydrogen production from coal by separating carbon dioxide during gasification. Fuel 81 (2002) 2079-2085.

The references recited here are incorporated herein in their entirety, particularly as they relate to teaching the level of ordinary skill in this art and for any disclosure necessary for the commoner understanding of the subject matter of the claimed invention. It will be clear to a person of ordinary skill in the art that the above embodiments may be altered or that insubstantial changes may be made without departing from the scope of the invention. Accordingly, the scope of the invention is determined by the scope of the following claims and their equitable equivalents.

TABLE 1

Carbonation processes

Solvay process	CO₂+ NaCl + NH₃+ H₂O → NaHCO₃+ NH₄Cl	Widely used in industry for Na₂CO₃
		and NaHCO₃production
K. S. Lackner, C. H. Wendt, D. P. Butt, E. L. Joyce	CaO (MgO) + CO₂→ Ca(Mg)CO₃,
and D. H. Sharp, Carbon dioxide	as well as carbonation of different
disposal in carbonate minerals. Energy	Mg and Ca silicate minerals, e.g.
20(11) 1153-1170(1995).	0.5CaMg(SiO₃)₂+ CO₂→ 0.5CaCO₃+ 0.5MgCO₃+
K. S. Lackner, Carbonate chemistry for	SiO₂Carbon dioxide absorption by
sequestering fossil carbon. Annu. Rev.	alkaline-earth metal or alkaline metal
Energy Environ. 27(2002) 193-232.	hydroxides including NaOH + CO₂+ H₂O → 2NaHCO₃
	reaction.
G. H. Rau and K. Caldeira, Enhanced	CaCO₃+ CO₂+ H₂O → Ca(HCO₃)₂
carbonate dissolution: a means of	with disposal Ca(HCO₃)₂in ocean
sequestering waste CO₂as ocean	water
bicarbonate. Energy Conver. Manag.
40(1999) 1803-1813.
S. Lin, M. Harada, Y. Suzuki and H. Hatano,	CaO + 2H₂O + C → CaCO₃+ 2H₂	Elevated pressure is required; CaO is
Hydrogen production from coal by	600-700° C.;	produced mainly from CaCO₃,
separating carbon dioxide during	3-5 MPa	thus there is no real CO₂
gasification. Fuel 81(2002) 2079-2085.		sequestration
X. Xu, Y. Xiao and C. Qiao, System design
and analysis of direct hydrogen from coal
system with CO₂capture. Energy & Fuel
21 (2007) 1688-1694.
T. Kamo, K. Takaoka, J. Otomo and H. Takahashi,	PVC + AR + H₂O → carbonate + H₂
Production of hydrogen by	AR - KOH; NaOH; Ca(OH)₂;
steam gasification of dehydrochlorinated	Na₂CO₃
poly(vinil chloride) or activated carbon in	560-660° C.; 3.0 MPa
presence of various alkali compounds. J. Mater.
Cycles Waste Manag. 8 (2006)
109-115.
A. Iizuka, M. Fujii, A. Yamasaki and Y. Yanagisawa,	Absorption of CO₂by Mg and Ca
Development of a new CO2	concrete and steel slag leachates.
sequestration process utilizing the
carbonation of waste cement. Ind. Eng.
Chem. Res. 434(24) 7880-7887 (2004).
J. K. Stolaroff, G. V. Lowry and D. W. Keith,
CO₂Extraction from Ambient Air
Using Alkali-Metal Hydroxide Solutions
Derived from Concrete Waste and Steel
Slag. American Geophysical Union, Fall
Meeting 2003, abstract #GC32A-0207

TABLE 2

Cost calculation for materials in sequestering carbon and producing hydrogen. It is assumed that the cost of producing
NaOH locally at the plant varies between $50 to 200 per ton and the Na₂CO₃does not sell or sells for $100/ton. The calculations
are just examples. The actual production will involve optimization of the feeder input based on all reactions determined by the
market.

									Assuming H₂
									sells for $2000/
					Amount of			Material	ton, the cost of
		$	Na₂CO₃	If	CO₂or CO		H₂	cost of H₂	sequestering a
	NaOH	NaOH/	produced	Na₂CO₃	sequestered,		produced	produced $/	ton of CO₂or
Reaction	(ton)	ton	ton	sells for	(ton)	Cost calculation	in ton	ton	CO is

2NaOH + C + H₂O =	80	50	106	0	Zero emission	4,000 − 0	4	+1000
Na₂CO₃+	80	100	106	100	Zero emission	8,000 − 10,600 = −2600	4	−650
2H₂“Hydro”	80	150	106	100	Zero emission	12000 − 10600 = 1400	4	+350
	80	200	106	100	Zero emission	16,000 − 10,600 = 5400	4	+1350
4NaOH + CO₂+ C =	160	50	212	0	44	8,000 − 0 = 8000	4	+2000	0
2Na₂CO₃+	160	100	212	100	44	16,000 − 21,200 =	4	−1300	−300
2H₂“CO2”						−5200
	160	150	212	100	44	24,000 − 21,200 = 2800	4	+700	−118
	160	200	212	100	44	32,000 − 21,200 = 10800	4	+2700	6.3
2NaOH + CO =	80	50	106	0	28	4000 − 0 = 4000	2	+2000	0
Na₂CO₃+	80	100	106	100	28	8,000 − 10600 = −2600	2	−1300	−236
H₂“CO”	80	200	106	100	28	16000 − 10600 = 5400	2	+2700	+50
6NaOH + CO2 + 2C +	240	50	318	0	44	12000 − 0	8	+1500	−91
H₂O =	240	100	318	100	44	24000 − 318000 = 7800	8	−975	−187
3Na₂CO₃+	240	200	318	100	44	48000 − 31800 = 16200	8	+2025	+4.6
4H₂“Hydro + CO2”
4NaOH + CH₄+	160	50	212	0	44	8,000 − 0 = 8000	8	+1000	−182
CO₂=	160	100	212	100	44	16,000 − 21200 = −5200	8	−650	−481
2Na₂CO₃+ 4H₂	160	200	212	100	44	32,000 − 21,200 = 10800	8	+1350	−118
4NaOH + CH₄+ CO +	160	50	212	0	28	8000 − 0 = 8000	10	+800	−428
H₂O =	160	100	212	100	28	16000 − 212000 = −5200	10	−520	−900
2Na₂CO₃+ 5H₂	160	200	212	100	28	32000 − 21200 = 10800	10	+1080	−329

Using present technology, estimates of sequestration costs are in the range of $100 to $300/ton of carbon emissions avoided. The goal of the DOE program is to reduce the cost of carbon sequestration to $10 or less per net ton of carbon emissions avoided by 2015. Achieving this goal would save the U.S. trillions of dollars. The numbers in the top row for each reaction are for the extreme possibility that NaOH can be produced cheaply using nuclear energy and we have to bury all unused Na₂CO₃coal and natural gas not taken into account.
Notes:
1. Material cost of H2 calculated as: (col (2) × col (3) − col (4) × col (5))/col (8). CO2 sequestration cost = (col (2) × col (3) − col (4) × col (5) − col (8) * 2000)/col (6).

TABLE 3

The use of soda in sequestering additional CO₂. The cost of soda is calculated
from the data in Table 2.

		Soda						If
		production	NaHCO3	Selling	Tons of		Cost of per	NaHCO₃
	Soda	cost/	produced	price of	CO₂		ton CO₂	is not
Reaction	tons	ton	tons	NaHCO3	sequestered	Cost calculation	sequestered,	sold

4NaOH + CO₂+ C = 2Na₂CO₃+	212	0	340	0	88	0 − 0 = 0	0	0
2H₂“CO2” and	212	37.8	340	50	88	8000 − 17000 = −9000	−102	91
2Na₂CO₃+ 2CO₂+ 2H₂O =	212	75.5	340	50	88	16000 − 17000 = −1000	−2.95	182
4NaHCO₃	212	113.2	340	50	88	24000 − 17000 = 7000	79.5	273
2NaOH + CO = Na₂CO₃+ H₂“CO”	106	0	170	0	56	0 − 0 = 0	0	0
and	106	37.74	170	50	56	4,000 − 8500 = −4500	−80.4	71.4
Na₂CO₃+ CO₂+ H₂O = 2NaHCO₃	106	113.2	170	50	56	12000 − 8500 = 3500	+62.5	214.3
4NaOH + CH₄+ CO₂= 2Na₂CO₃+	212	37.74	340	0	88	8,000 − 16000 = −8000	−91	91
4H₂and	212	0	340	50	88	0 − 17000 = −−17000	−−193.2	0
2Na₂CO₃+ 2CO₂+	212	75.5	340	50	88	16000 − 17000 = −1000	−−11.4	181.8
2H₂O = 4NaHCO₃
4NaOH + CH₄+ CO + H₂O =	212	−56.6	340	0	56	−12000 − 0 = −12000	−214.3	−214.3
2Na₂CO₃+ 5H₂and	212	−18.86	340	50	56	−4000 − 17000 = −21000	−375	−71.4
2Na₂CO₃+ 2CO₂+ 2H₂O =	212	56.6	340	50	56	12000 − 17000 = −5000	−89.3	214.3
4NaHCO₃

Notes:
1. Soda production cost is from Table 2, (Cost of NaOH × tons of NaOH − 2000(cost of 1 ton of H₂) × tons of H₂)/tons of soda produced.
2. Production of NaHCO₃is according to the bicarbonate reaction (mol. Wt. 85 gm/mole × no. of moles × 1000).
3. Cost of per ton CO₂sequestered = (col. (2) × col. (3) − col. 4 × col (5))/col. 6). The calculations are just examples. The actual production will involve optimization of the feeder input based on all reactions determined by the market.

Claims

1. A process to sequester carbon from flue gas of a power plant, comprising: reacting sodium hydroxide with an oxide of carbon from the flue gas to form sodium carbonate.

2. The process of claim 1, further comprising wherein the oxide of carbon is carbon monoxide or carbon dioxide.

3. The process of claim 2, further comprising the step of adding natural gas and water to the carbon monoxide—sodium hydroxide reaction to produce sodium carbonate, or adding water to the carbon monoxide-sodium hydroxide reaction to produce sodium bicarbonate.

4. (canceled)

5. (canceled)

6. The process of claim 2, further comprising the step of adding coal to the carbon dioxide—sodium hydroxide reaction to produce sodium carbonate, or adding natural gas and water to the carbon dioxide—sodium hydroxide reaction to produce sodium carbonate, or adding water to the carbon dioxide—sodium hydroxide reaction to produce sodium bicarbonate.

7. (canceled)

8. (canceled)

9. The process of claim 1, further comprising wherein the power plant is a coal-burning power plant or a natural gas-burning power plant.

10. (canceled)

11. The process according to claim 1, further comprising the step of generating hydrogen from the reaction.

12. The process according to claim 1, further comprising the steps of: conducting the reaction in a closed system to achieve zero emission of carbon gases, and generating hydrogen from the reaction.

13. The process according to claim 1, further comprising the step of: using a form of energy obtained from the coal-burning plant to conduct said process, wherein said form of energy is selected from hot air, electric energy in off-peak production, or both.

14. The process according to claim 1, further comprising the steps of: using any gas mixtures exhausting from the power plant; and adjusting the composition of the feed stock (sodium hydroxide) to react with components of gas selected from sulfur dioxide, nitric oxide, or both; and forming removable solids.

15. The process according to claim 1, further comprising the step of: using one or more catalysts to promote the reaction kinetics.

16. The process according to claim 1, further comprising wherein the process of carbonation is not a direct conversion of NaOH to Na₂CO₃but is a result of a reaction with other solids and gases usually producing hydrogen in important amounts.

17. The process according to claim 1, further comprising the step of: using an integrated design for the execution of the processes such that the waste-energy provided by the coal burning power plant is used effectively by adhering to energy saving schedules which comprise off-peak utilization.

18. The process according to claim 1, further comprising the step of: producing the sodium hydroxide at the site using energy selected from the power plant itself, nuclear, solar, wind, hydro-electric, alternate energy sources other than coal or any other fossil fuel, or combinations thereof.

19. The process according to claim 1, further comprising the step of: recovering additional cost by selling reaction products selected from sodium carbonate, sodium bicarbonate, hydrogen, chlorine, or combinations thereof, at market prices to recover any additional costs that are incurred due to the use of sodium hydroxide.

20. A system for sequestering carbon from flue gas of a power plant, comprising:

(a) a burner for combusting a mixture of oxygen and fuel and generating flue gas and products of combustion;

(b) a stack in communication with said burner for collection and dispersion of the flue gas and the products of combustion; and

(c) a reactor for reacting sodium hydroxide with an oxide of carbon from the flue gas to form sodium carbonate.

21. The reactor of claim 20, further comprising wherein the oxide of carbon is carbon monoxide or carbon dioxide.

22. The reactor of claim 21, further comprising means for adding natural gas and water to the carbon monoxide—sodium hydroxide reaction to produce sodium carbonate, or adding water to the carbon monoxide-sodium hydroxide reaction to produce sodium bicarbonate.

23. (canceled)

24. (canceled)

25. The reactor of claim 24, further comprising means for adding coal to the carbon dioxide—sodium hydroxide reaction to produce sodium carbonate, or adding natural gas and water to the carbon dioxide—sodium hydroxide reaction to produce sodium carbonate, or adding water to the carbon dioxide—sodium hydroxide reaction to produce sodium bicarbonate.

26. (canceled)

27. (canceled)

28. The reactor of claim 20, further comprising wherein the power plant is a coal-burning power plant or a natural gas-burning power plant.

29. (canceled)

30. The reactor according to claim 20, further comprising means for generating hydrogen from the reaction.

31. The reactor according to claim 20, further comprising means for conducting the reaction in a closed system to achieve zero emission of carbon gases, and means for generating hydrogen from the reaction.

32. The reactor according to claim 20, further comprising means for using a form of energy obtained from the coal-burning plant to conduct said process, wherein said form of energy is selected from hot air, electric energy in off-peak production, or both.

33. The reactor according to claim 20, further comprising means for using any gas mixtures exhausting from the power plant; and means for adjusting the composition of the feed stock (sodium hydroxide) to react with components of gas selected from sulfur dioxide, nitric oxide, or both; and forming removable solids.

34. The reactor according to claim 20, further comprising means for using one or more catalysts to promote the reaction kinetics.

35. The reactor according to claim 20, further comprising wherein the reactor of carbonation is not a direct conversion of NaOH to Na₂CO₃but is a result of a reaction with other solids and gases which produce hydrogen in substantial amounts.

36. The reactor according to claim 20, further comprising means for using an integrated design for the execution of the processes such that the waste-energy provided by the coal burning power plant is used effectively by adhering to energy saving schedules which comprise off-peak utilization.

37. The reactor according to claim 20, further comprising means for producing the sodium hydroxide at the site using energy selected from the plant itself, nuclear, solar, wind, hydro-electric, alternate energy sources other than coal or any other fossil fuel, or combinations thereof.

38. The reactor according to claim 20, further comprising means for recovering additional cost by selling reaction products selected from sodium carbonate, sodium bicarbonate, hydrogen, chlorine, or combinations thereof, at market prices to recover any additional costs that are incurred due to the use of sodium hydroxide.

39. The reactor according to claim 20, wherein the reactor is a retrofit module for an existing or a new power plant.

40. The process of synthesizing a hydride such as magnesium hydride linked to the hydrogen being produced in the reactor according to claim 20.