SYSTEMS AND METHODS FOR REACTOR CHEMISTRY AND CONTROL

1 . A solar-driven chemical plant that manages variations in solar energy, comprising:

a solar thermal receiver aligned to absorb concentrated solar energy from one or more solar energy sources including 1) a single mirror, heliostat, or solar-concentrating dish, 2) an array of heliostats, 3) two or more solar-concentrating dishes, and 3) any combination of the three;

a solar driven chemical reactor at least partially contained within the solar thermal receiver;

an entrained gas biomass feed system that uses an entrainment carrier gas and supplies a variety of biomass types fed as particles into the solar driven chemical reactor;

inner walls of the solar thermal receiver and the chemical reactor made from materials selected to transfer energy by primarily heat radiation, along with convection, and conduction to the reacting biomass particles to drive the endothermic gasification reaction of the particles of biomass flowing through the chemical reactor;

a control system configured to balance the gasification reaction of biomass particles with the available concentrated solar energy and additional variable parameters including a fixed range of particle sizes, operating temperature of the chemical reactor, and residence time of the particles in a reaction zone in the chemical reactor so that an overall biomass particle conversion remains above a threshold set point of greater than 90 percent of the carbon content of the particles into reaction products that include hydrogen and carbon monoxide gas; and

a feedforward portion and a feedback portion of the control system configured to adapt for both long and short term disturbances in available solar energy, wherein the feedforward portion anticipates cyclic changes in solar energy due to at least a time of day, day of the year, short-term cloud, dust, smoke or other obscuring events, or long-term weather events, with a predictive model that adapts to the anticipated cyclic changes, and wherein the feedback portion measures actual process parameters including the operating temperature of the chemical reactor and then uses these measurements in the balancing of the gasification reaction of biomass particles.

2 . The solar-driven chemical plant of claim 1 , further comprising:

one or more temperature sensors to detect the operating temperature of the chemical reactor at an entrance and an exit and supply that measurement to the feedback portion of the control system,

two or more reactor tubes in the chemical reactor in which the biomass particles flow in and located within the solar thermal receiver,

one or more feed lines which supply to the reactor tubes the particles of biomass in the fixed range of particle size controlled to an average smallest dimension size between 50 microns (um) and 2000 um, with a general range of between 200 um and 1000 um,

wherein the control system maintains the temperature of the tubes of the chemical reactor at a steady state temperature exceeding 1000 degrees C., above transitory minimum temperature of 800 degrees C. and below peak temperatures of 1600 degrees C.,

wherein the control system balances the gasification reaction of biomass particles with the available concentrated solar energy so that the overall biomass particle conversion temperature remains above a threshold set point of substantial tar destruction resulting in less than or equal to 50 mg/Nm̂3 of tar and the gasification of greater than 90 percent of the carbon content of the particles, and

where the residence time of the particles of biomass in the reaction zone in the chemical reactor is between a range of 0.01 and 5 seconds.

3 . The solar-driven chemical plant of claim 1 , further comprising:

an amount of solar energy available indicated by one or more temperature sensors in the chemical reactor and one or more light meters to provide the actual process parameters information to the feedback portion of the control system;

two or more reactor tubes in which gasification occurs in a vertical orientation in the chemical reactor in which the gasification occurs;

a separate feed line is used to feed biomass particles for each of the reactor tubes in the chemical reactor, which allows independent temperature control and balancing of amount of particles of biomass flowing in each of the reactor tubes in the multiple tube solar-driven chemical reactor;

a lock hopper system in the feed system, where the particles of biomass feed are distributed to the separate carrier gas entrainment line by the lock hopper feed system, in which feed rate of the biomass particles is controlled by a metering device, which responds to a feed demand signal received from the control system; and

an on-site chemical synthesis reactor that is geographically located on the same site as the chemical reactor and integrated to receive the hydrogen and carbon monoxide products from the gasification reaction, wherein the on-site chemical synthesis reactor has an input to receive the hydrogen and carbon monoxide products and use them in a hydrocarbon fuel synthesis process to create one or more of 1) a liquid hydrocarbon or alcohol fuel, 2) solid fuel, 3) liquid chemicals, 4) solid chemicals.

4 . The solar-driven chemical plant of claim 1 , further comprising:

a lock hopper having a metering device in a feed system having one or more feed lines coupled to the chemical reactor, wherein the control system sends a feed demand signal to the feed system to control a feed rate of the particles of biomass in the solar driven chemical reactor, where control of the multiple reactor tubes is split into two or more groups of tube subsets, where the control system balances the amount of biomass particles flowing into each of the reactor tubes to an amount of solar energy available by 1) controlling a rotational rate of a screw of a lock hopper feeding the biomass where all the tubes in the tube subset have their feed rate simultaneously turned up or turned down, 2) varying an amount of the reactor tube-subsets participating in the gasification reaction by turning on or turning off a flow of particles of biomass from the lock hopper to the reactor tubes making up a tube subset, or 3) a combination of both.

5 . The solar-driven chemical plant of claim 1 , further comprising:

a spray nozzle to supply water to the product gas exiting the chemical reactor to shift some of the product carbon monoxide to additional hydrogen and carbon dioxide gas in a water gas shift reaction, making the hydrogen to carbon monoxide ratio appropriate for the planned syngas use.

6 . The solar-driven chemical plant of claim 2 , wherein the control system is configured to balance chemical reaction types, including the biomass gasification reaction, a stream reforming reaction, a dry reforming reaction and various combinations of these reactions within the solar driven chemical reactor, to an amount of concentrated solar energy available directed at the solar thermal receiver in order to keep the solar chemical reactor at a temperature at which the chemical reactor operates high enough to maintain the generated syngas within a set molar ratio of H2 to CO ratio of 2.1 to 2.8, with being substantially tar free having less than 200 Mg/M̂3, and having less than 7% by volume CO in the generated syngas.

7 . The solar-driven chemical plant of claim 1 , further comprising:

an amount of surface area, thermal mass, and heat capacity is built into the receiver and can be in the form of the receiver walls, insulation, or reactor tubes;

one or more temperature sensors at the entrance and/or exit of the reactor tubes;

an operational temperature range of below 1600 degrees C. and above 800 degrees C. in the chemical reactor during daily weather conditions, which are subject to rapid changes in solar availability; and

a feed demand signal from the control system to control the feed rate of particles of biomass in the solar driven chemical reactor by the feedforward/feedback model-predictive scheme in cooperation with designing in enough surface area, thermal mass, and heat capacity in the multiple tubes and receiver cavity to ensure that temperature of the reactor cavity remains in the operational temperature range of below 1600 degrees C. and above 800 degrees C. during the rapidly changing daily weather conditions, wherein the feed forward model predicts an available solar energy over each time period in a given day as well as each day throughout the year, the feedback portion receives dynamic feedback from sensors, including temperature sensors, and they are combined to maintain both the quality and output of resultant syngas at above the threshold set point of substantial tar destruction resulting in less than or equal to 50 mg/m̂3 and complete gasification of greater than 90 percent of the carbon content of the biomass particles into the reaction products, wherein the enough surface area and thermal mass of the cavity and reactor tubes is built into the multiple tubes and receiver cavity, to act as a ballast, averaging out very short term small fluctuations (second to second) in the available solar energy to have a negligible ramp-up and ramp-down of temperature of the receiver and reactor due to these instantaneous changes in available solar energy, thereby allowing the ramp-up and ramp-down of the feed rate of biomass particles to be more gradual as well.

8 . The solar-driven chemical plant of claim 7 , further comprising:

an insulation layer around the cavity is set thick enough to control conduction losses to less than 5% of the peak solar input, wherein the receiver cavity temperature is a controlled parameter, which the control system then primarily controls by modulating a flow rate of biomass particles through the reactor tubes balanced against the predicted feedforward available amount of solar energy and the dynamically determined feedback amount of available solar energy.

9 . The solar-driven chemical plant of claim 7 , further comprising:

a composition analyzer at the exit of the reactor system to sense changes in the hydrogen, carbon monoxide, carbon dioxide, methane, tar composition, or any combination thereof of the syngas, where the composition analyzer provides a dynamic signal to the feedback portion of the control system and upon readings of any of the hydrogen, carbon monoxide, carbon dioxide, methane, tar compositions of the syngas that are above a threshold, where the control system sends a signal to divert the reactant products of the gasification reaction to a recycling line back into the entrance to the chemical reactor to avoid damage to filters, compressors, catalytic systems, and other components in the downstream portions of the solar gasification and/or liquid fuel and/or chemical synthesis process.

10 . The solar-driven chemical plant of claim 1 , wherein the biomass particles being fed from the entrained flow biomass feed system undergo several distinct chemical processes of the gasification reaction prior to exiting the reactor tubes including:

pyrolysis of the biomass particles into 1) carbonaceous char and 2) volatile components vaporized into gas products;

gasification of the carbonaceous char including lignin fractions into gaseous products including carbon monoxide, hydrogen, and tars; and

cracking of the tars, including larger hydrocarbons and aromatic compounds collectively known as tars, at greater than 1000 degrees C. to produce substantial tar destruction resulting in less than or equal to 50 mg/m̂3 and complete gasification of greater than 90 percent of the carbon content of the biomass particles into reaction products including hydrogen and carbon monoxide gas, wherein the steps of complete gasification and cracking of tars starts and finishes within the residence time of the biomass particles in the reaction zone in the chemical reactor between the range of 0.01 and 5 seconds.

11 . The solar-driven chemical plant of claim 3 , further comprising:

one or more detectors indicate an amount of solar energy available in different areas of the solar receiver to guide the control system in balancing an amount of the biomass particles flowing in each of the reactor tubes;

a 2-phase pinch valve system on each feed line to each reactor tube, wherein the control system balances the amount of biomass particles flowing in each of the reactor tubes to the amount of solar energy available by sending a dynamic feedback control signal to the 2-phase pinch valve system to control an amount of compression of a flexible pipe section of the feed line that the biomass particles are flowing through to control flow in the individual reactor tubes, and where the detectors indicate the amount of solar energy available to guide the control system; and

wherein an on-site fuel synthesis process has an input to receive a filtered form of the hydrogen and carbon monoxide gas from the reaction products and process them to store the concentrated solar energy in chemical bonds of the biomass as an easily storable and transportable liquid hydrocarbon fuel, where the liquid hydrocarbon fuel is one or more of jet fuel, DME, gasoline, diesel, methanol, mixed alcohol, synthetic natural gas, heating oil, and synthetic crude oil.

12 . The solar-driven chemical plant of claim 2 , further comprising:

a shape and width of the outlet of the feed line pipe carrying the biomass particles to its corresponding reactor tube to control a dispersion pattern of biomass particles entering each reactor tube and the greater than 90% gasification of the carbon content of the particles occurs because of both 1) the high operating temperatures of greater than 1000 degrees C. and 2) that the biomass particles are well separated from one another in a flowing disperse cloud of very fine biomass particles; and

wherein the resulting CO to CO2 ratio is controllable through a range of greater than or equal to 5:1.

13 . The solar-driven chemical plant of claim 2 , further comprising:

a material making up the reactor tubes possesses high emissivity of 0.8 emissivity coefficient or better, high thermal conductivity of 30 watts per meter-Kelvin or better, at least moderate heat capacity of 8 joules per mole-degree Kelvin or better, and is resistant to the oxidizing air environment in the solar receiver cavity and the reducing environment of the biomass gasification reaction inside the tubes in order to support operating temperatures within the tubes in the tar cracking regime between 800-1350 degrees C., wherein this operating temperature eliminates any need for tar cracking equipment downstream of the chemical reactor, and where in addition the operation at the high operating temperature in the reactor tubes improves heat transfer, minimizes methane from the exit gases, and decreases required residence time of the biomass particles to achieve complete gasification, which in turn decreases a physical size of the chemical reactor itself.

14 . The solar-driven chemical plant of claim 2 , further comprising:

a material or materials and an indirect solar gasifier design of the multiple reactor tubes allows for feedstock flexibility in the type of biomass making up the particles of biomass, and obviates any need for an exothermic/endothermic reaction balancing in the chemical reactor design because the concentrated solar energy drives the endothermic gasification reaction and a radiation-based heat transfer balancing makes the endothermic reaction gasification quite forgiving in terms of internal reaction balance, and thus, at least two or more different types of biomass materials can be used in the same multiple reactor tube geometry of the chemical reactor, obviating any need for a complete reengineering when a new type of biomass feedstock is used, where the two or more different types of biomass materials that can be fed from the feed system, individually or in combinational mixtures, are selected from the group consisting of rice straw, rice hulls, corn stover, switch grass, wheat straw, miscanthus, orchard wastes, sorghum, forestry thinnings, forestry wastes, agricultural wastes, source separated green wastes and other similar biomass sources, as long as a few parameters are controlled including the particle size of the biomass and operating temperature of the chemical reactor.

15 . The solar-driven chemical plant of claim 2 , further comprising:

an insulation layer around the receiver with resistance heaters connected to the solar receiver walls to assist with maintaining temperature in the 800-1600 degree C. range,

where waste heat from either the spill of concentrated solar energy not entering the aperture of the receiver, the solar gasification process, or some other available heat-producing process, heats a working fluid that directly or indirectly supplies energy to electrical generation machinery or heats high-temperature storage material that can be a solid, liquid, or gas, which will later be used to heat a working fluid, which directly or indirectly supplies energy to electrical generation machinery, to supply a source of power for including at least the resistance heaters,

where the control system can turn on and off the resistance heaters as additional heat sources for maintaining temperature as need be, wherein the control system supplies a control signal to 1) the feed system, 2) the solar energy concentrating fields, 3) and the supplemental resistance heating system, and

wherein the lag times and response times of the: 1) solar energy concentrating fields to alter alignment and an amount of concentrated solar energy supplied, 2) feed system to alter an amount of biomass flowing in the reactor tubes, and 3) time for weather events to alter an amount of solar energy available, are factors taken into account by a control algorithm in the control system in sending out the control signals to the feed system, the solar energy concentrating fields and the supplemental resistance heating system.

16 . The solar-driven chemical plant of claim 2 , further comprising:

a carrier gas supply line that supplies the entrainment gas as a pressurized dry steam, and/or where natural gas is fed along with the biomass particles during a co-gasification of 1) biomass in the presence of steam and 2) steam reforming of natural gas, and the pressurized dry steam is generated from waste heat recovered from either the spill of concentrated solar energy not entering an aperture in the receiver, the solar gasification process, or some other available heat-producing process.

17 . The solar-driven chemical plant of claim 2 , wherein the control system utilize different models that are selected depending on the system and variable state, and include insolation perturbations categorized into 3 types: 1) short events, including weather events in duration from 0-5 hours 2) medium events, including diurnal events in duration from 5-14 hours, and 3) long-term events in duration more than 14 hours.

18 . The solar-driven chemical plant of claim 2 , wherein the computerized control system is configured to receive a feedback signal from a set of sensors, an amount of solar energy available indicated by one or more temperature sensors in the chemical reactor and one or more light meters provides the actual process parameters information to the feedback portion of the control system, a feed vessel in the feed system responds to a feed demand signal from the computerized control system, and the computerized control system controls a flow rate of particles of biomass in the solar-driven chemical reactor based on an amount of solar energy available indicated by sensors for the chemical reactor.

19 . A method of generating syngas products for a solar-driven chemical plant that manages variations in solar energy, comprising:

focusing concentrated solar energy to a solar driven chemical reactor contained within the solar thermal receiver;

supplying biomass particles into one or more tubes in the solar driven chemical reactor;

driving an endothermic gasification reaction of the particles of biomass flowing through the tubes of the chemical reactor by primarily heat radiation from the inner walls of the solar thermal receiver and the tube surfaces of the chemical reactor by the absorbed concentrated solar energy;

balancing the gasification reaction of biomass particles with the available concentrated solar energy and additional variable parameters of 1) a fixed range of particle size, 2) operating temperature of the chemical reactor, and 3) residence time of the particles in a reaction zone in the chemical reactor so that an overall biomass particle conversion remains above a threshold set point of substantial tar destruction resulting in less than or equal to 50 mg/Nm̂3 of tar and gasification of greater than 90 percent of the carbon content of the particles into reaction products that include hydrogen and carbon monoxide gas; and

adapting to short-term disturbances in duration, medium-term disturbances in duration, and long-term disturbances in duration in available solar energy, wherein a control system anticipates changes in solar energy due to at least a time of day, day of year, periodic meteorological reports, solar field condition, and biomass type and condition, with a predictive model that adapts to the anticipated cyclic changes, and wherein a feedback component measures actual process parameters including the temperature of the chemical reactor and uses the these measurements in the balancing the gasification reaction of biomass particles.

20 . A method for a solar driven chemical plant, comprising:

conducting a chemical reaction in a solar driven chemical reactor having multiple reactor tubes using concentrated solar energy to drive the conversion of the chemical reactant, wherein an endothermic chemical reaction conducted in the reactor tubes includes one or more of the following: biomass gasification, steam methane reforming, methane cracking, steam ethane or naphtha cracking to produce ethylene and related olefins, or carbon dioxide reduction or water splitting, using solar thermal energy coming from a concentrated solar energy field; and

starting an entrained-flow of chemical reactants into the chemical reactor for the endothermic chemical reaction when 1) the solar energy concentrating field is aligned at an aperture of the solar thermal receiver containing the solar driven chemical reactor, and 2) the solar driven chemical reactor is at least a minimum operational temperature of 800 degrees Celsius and preferably greater than 1000 degrees Celsius.