TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: In the solar-driven chemical reactor system, the endothermic chemical reaction is at least biomass gasification, and the materials selected for the inner cavity wall and the reactor tubes combined with an amount of concentrated solar energy from at least one solar energy concentrating field cause heat transfer from the cavity walls and reactor tubes to transfer heat in a sufficient amount to the particles of biomass flowing in the reactor tubes to achieve the temperature necessary for substantial tar destruction and gasification of greater than 90% of the biomass particles into reaction products, including hydrogen and carbon monoxide gas, in a very short residence time of 0.01-5 seconds. The solar-driven chemical reactor system further comprises: a length and diameter dimensions of a gasification reaction zone of each of the reactor tubes, along with an arrangement and an amount of the tubes are matched to an amount of solar energy from the heliostat field to give the fast residence time of 0.01-5, preferably 2-3 seconds, at the biomass gasification temperature of greater than 950 degrees C, where: the first of the multiple tubes that has a different diameter than the second of the multiple tubes, has a larger diameter and is located in a higher solar flux concentration and/or higher temperature zone in the cavity of the receiver than the second tube; the geometrical configuration of the multiple reactor tubes in the receiver relative to each other is in a linear pattern, semi-circular pattern, arc pattern, cylindrical pattern, rectangular pattern or some other arbitrary arrangement; an inner diameter of the reactor tubes is sized to allow a substantially uniform gasification of the biomass particles from the edges to the center of the tube, and have a wall thickness of \8-2 inches, that is set to withstand at least a 75 psig pressure when the inside tube walls are at 1400 degrees C; and an on-site chemical synthesis reactor that is geographically located on the same site as the chemical reactor and has an input to receive the gasification products including hydrogen and carbon monoxide for a hydrocarbon synthesis process performed in the on-site chemical synthesis reactor to create hydrocarbon fuels and/or chemicals. In the solar-driven chemical reactor system, the shape of each reactor tube is a cylindrical shaped pipe, and at least 30 reactor tubes are present in the cavity of the solar thermal receiver, the geometric arrangement of the 30 reactor tubes relative to each other is an arc pattern, and a shape of the aperture is approximately a square, where at least some the products resulting from the chemical reaction in the solar driven chemical reactor are supplied to an input of a downstream chemical synthesis processes, in which methanol is generated and then supplied to a methanol-to-gasoline process. The solar-driven chemical reactor system further comprises: at least two zones in the receiver in which the reactor tubes in each zone are made out of different materials to adapt to an amount of heat flux in that zone, peak temperature of that zone and corrosion conditions in that zone; a tower that supports and elevates the solar thermal receiver and solar driven chemical reactor, where the tower is at least tall enough, which is greater than or equal to 100 meters in height to give an optimized angle of elevation for the solar energy concentrating field to supply the concentrated solar energy to the solar thermal receiver and solar driven chemical reactor while minimizing an amount of heliostats or solar concentrating dishes and acreage of land occupied by these heliostats or solar concentrating dishes needed to deliver an amount of concentrated solar energy to the apertures with a flux of 750-3500 kW/m2, and the concentration of solar energy into the apertures achieves the heat transfer rates at the inner wall of the cavity and reactor tubes to allow the particles of biomass to achieve the temperatures necessary for substantial tar mitigation to less than 50 mg/m3 and to gasification of greater than 90% of the biomass particles into reactant products. In the solar-driven chemical reactor system, a first solar energy concentrating field is an arrangement of heliostats in rows of differing spacing so that as the distance of each row of heliostats from the receiver is increased, the height of the heliostats in that row is increased and also the spacing between heliostat rows is increased, where the non-uniform heliostat field is used to generate an average concentration of solar energy at the aperture of the receiver greater than or equal to 500 times the direct normal insulation concurrently incident upon the solar energy concentrating field. The heliostat field has greater than 25000 m2 of reflecting surface that cooperates with the solar thermal receiver to control an amount of solar energy into the apertures and onto the reactor tubes and cavity walls, hence maintaining the temperature required for gasification of greater than 90% of the biomass particles into the reactant products that include the hydrogen and carbon monoxide gas in a residence time of 0.01-5 seconds, where the size and a shape of each of the apertures of the receiver is determined by the balance between the power in the portion of the focus of the heliostat field accepted into the aperture and the total amount of energy that is needed to achieve the residence times. The heliostat field has greater than 100000 m2 of reflecting surface that cooperates with the solar thermal receiver to control an amount of solar energy flux across the apertures that is applied to reactor tubes and cavity walls to allow enough energy from a radiant energy to raise the heat inside the tubes to initiate and sustain a sufficiently high temperature so that the gasification occurs of greater than 90% of the biomass particles into the reactant products that include the hydrogen and carbon monoxide gas in a residence time of 0.01-2 seconds, where the solar energy concentrating field generates an average concentration of solar energy at the aperture of the receiver greater than or equal to 1000 times the direct normal insulation concurrently incident upon the solar energy concentrating field. The solar-driven chemical reactor system further comprises: baffles positioned at selective locations within the cavity of receiver and combined with an intertube radiation exchange between the multiple reactor tube geometric arrangement relative to each other is used to shape a distribution of incident radiation via reflection or absorption within the receiver cavity, where the concentrated solar energy field is a heliostat field and the concentrated solar energy from the heliostat field is in an amount of concentration of sun sufficient to produce greater than or equal to 750 kW/m2 of solar energy at the apertures, which gives the receiver cavity to have a capacity of at least 2000 kW, the multiple tube construction of the cavity increases the surface area for radiative transfer to the reactants in the chemical reaction over a common reaction tube; a shape of the reactor tubes is substantially rectangular, which also yields a higher surface area for equivalent volume than cylindrical shaped tubes; a tower supporting an elevated solar thermal receiver and solar driven chemical reactor, where the tower is tall enough, at least 100 meters, in height to give an optimized angle of elevation for the non-uniform heliostat field; each heliostat has a mirror, where the array of mirrors in the heliostat field are configured to obtain both dense packing in at least the first third of the part of the field near the receiver, where the highest proportion of energy off of each of the mirrors in the dense packed portion of heliostats intercepts the apertures or windows of the receiver, and optimal small shading and minimal blocking occurs for the mirrors in the heliostat field due to the angle of elevation of the heliostat field to the solar thermal receiver on the tower, in combination with the staggered heights and the spacing of the rows of the non-uniform heliostat field; and a high concentration of solar energy directed from the solar energy concentrating field to the receiver to give a normal distribution greater than or equal to 3000-5000 kW/m2 peak solar energy in the flux at the apertures of the receiver cavity, with an average solar energy in the 1000-2500 kW/m2 depending on the time of day, to have a capacity of at least 2000 kW and generally around 80000 kW. In the solar-driven chemical reactor system, the receiver cavity, the multiple reactor tubes, and the apertures are shaped and sized to facilitate greater than 60% average aperture incident power to be converted into chemical or sensible energy at peak incident power, and thus greater than 60% of the amount of energy entering the receiver as solar energy ends up as chemical or sensible enthalpy leaving the reactor tubes, and also a conversion of carbon in the particles of biomass to carbon monoxide above 85% yield per ton of the biomass occurs from the gasification reaction in the tubes, where the receiver has at least one window covering the apertures and no apertures open to the atmosphere. In the solar-driven chemical reactor system, the receiver cavity, the multiple reactor tubes, and the apertures or windows are shaped and sized to map an amount of solar flux distribution to the reactor tube size and geometric position to allow a same rate of biomass gasification for a set biomass particle size range everywhere in a gasification zone in the tubes of the chemical reactor, and thus avoiding locally extremely high temperatures greater than 1500 degrees C or extremely low temperatures of less than 600 degrees C. The solar-driven chemical reactor system further comprises: at least one actuator, where the receiver has the apertures and no windows, and the apertures are articulated movable apertures that are capable of varying location on the solar thermal receiver based on the actuators moving the apertures; a computing device running a model of solar energy flux maps of the apertures that captures how the solar power delivered to the aperture changes over time under similar natural solar conditions to send control signals to and guide the actuators in moving the apertures; and at least one structure with high temperature storage material that absorb the concentrated solar energy contained within the cavity of the solar thermal receiver, where the cavity of the solar thermal receiver contains additional radiant heat masses, which have high temperature storage material that absorb the concentrated solar energy, and the radiant heat masses are used to keep the reactor tubes hot during long periods of off sun, during cyclic up and down times in the plant, and keep radiant temperature in the reactor less transient during normal operation, and at least one of these radiant heat masses are positioned in the cavity in areas of extremely high concentrated solar energy compared to other areas within the cavity to absorb some of the concentrated solar energy in that area to allow the reactor tubes to all use the same material. The apertures are part of a receiver outer shell that at least partially encloses the multiple reactor tubes, where a material making up the receiver inner wall absorbs, or the material highly reflects the concentrated solar energy to cause the radiant heat and then generally radiatively conveys that heat like an oven to the biomass particles in the reactor tubes, and one of a brick, a ceramic or a fiber insulation covers an outer wall of the receiver, where the inner wall operates at high wall temperature of greater than 1200 degrees C and the insulation thickness is designed to limit losses through conductive heat loss to less than 5% of the energy incident at peak solar input on the receiver apertures and a radiation shield that is movable across the aperture at night or other periods of extended shutdown to minimize an amount of radiation heat loss, which enables a rapid heat up to gasification temperatures when normal operations resume in the morning. The solar-driven chemical reactor system further comprises: an insulation layer around the cavity of the indirect radiation driven geometry, absorbing cavity, solar thermal receiver, where the receiver is configured with only the apertures and no windows, and the multiple reactor tubes are located in the center of the cavity; a thickness of the insulation layer is set to control conductive heat losses, where the cavity temperature and an average concentration of solar energy at the apertures control radiative losses; an aperture design, orientation and cavity working fluid (buoyancy) are also configured to control convective losses, where the inner cavity wall at least partially encloses the multiple reactor tubes to act like an oven, spreading heat flux around, via reflection or absorption and re-radiation and giving a much more even flux profile on the reactor tubes, both azimuthally and axially than the incident solar radiation by itself, an averaging effect on the heat flux radiated from the absorbing cavity walls and multiple tubes occurs within the cavity, and the solar energy concentrating field is a heliostat field that focuses an average concentrated solar energy from the moving sun of a west weighting to an east weighting across the aperture and subsequent impingement on the reactor tubes themselves through the course of each day, yet the reactor tubes provide a uniform radial reaction profile of the biomass particles through the course of each day due to the oven effect of the cavity along with the particle nature of biomass, which tend to average energy amongst themselves at their design volumetric loadings, combining to give the fairly uniform temperature profile and subsequent fairly uniform radial reaction profile of the biomass particles; at least one incident radiation shaping surface including baffles at selective locations within the cavity of receiver, along with the intertube radiation exchange between the multiple reactor tube geometric arrangements relative to each other is used to shape a distribution of incident radiation via reflection or absorption within the receiver cavity; a secondary concentrator on the solar thermal receiver to boost concentration of the concentrated solar energy, in which a surface geometry of the secondary concentrator and a field layout of at least one solar energy concentrating field is designed to avoid reflective and radiative losses from the area surrounding the aperture and the cavity of the solar thermal receiver; and a tower that supports and elevates the solar thermal receiver and solar driven chemical reactor, where the tower is at least 100 meters in height to give an optimized angle of elevation, which allows for a large number of heliostats including over 50% of the heliostat surface area making up the solar energy concentrating fields, to be visible from the point of view of the secondary concentrator, increases the concentration of solar energy at the apertures, improves the overall efficiency, and results in a higher plant capital utilization factor, where the receiver has the apertures and no windows.