NOVELTY - A solar-driven chemical plant managing variations in solar energy comprises a system for balancing gasification reaction of biomass particles; and feed-forward and feedback portions to adapt for long and short term disturbances in available solar energy. The feed-forward portion anticipates cyclic changes in solar energy due to a time of day, day of year, short-term cloud, dust, smoke or other obscuring events, or long-term weather events, with a predictive model that adapts to the changes. The feedback portion measures actual process parameters for balancing the reaction.    USE - As solar-driven chemical plant for generating syngas (claimed).    ADVANTAGE - The control system comprises both feed-forward and feedback elements that control balancing of the gasification reaction and results in negligible tar formation in resultant syngas products and waste products. Moreover, high pressure feeding of solids of biomass with gasification at pressure reduces capital cost due to the ability to use smaller compressors in some such systems.    DETAILED DESCRIPTION - A solar-driven chemical plant that manages variations in solar energy comprises: a solar thermal receiver aligned to absorb concentrated solar energy from at least one solar energy source including a single mirror, heliostat, or solar-concentrating dish, an array of heliostats, and/or at least two solar-concentrating dishes; a solar driven chemical reactor at least partially contained within the receiver; an entrained gas biomass feed system (600) that uses an entrainment carrier gas and supplies a variety of biomass types fed as particles into the reactor; inner walls of the 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 endothermic gasification reaction of the particles of biomass flowing through the reactor; a control system configured to balance the gasification reaction of biomass particles with available concentrated solar energy and additional variable parameters including a fixed range of particle sizes, operating temperature of the reactor, and residence time of the particles in a reaction zone in the reactor so that overall biomass particle conversion remains above a threshold set point of greater than 90% of the carbon content of the particles into reaction products that include hydrogen and carbon monoxide gas; and a feed-forward portion and a feedback portion of control system configured to adapt for both long and short term disturbances in available solar energy, where the feed-forward 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, where the feedback portion measures actual process parameters including operating temperature of the reactor and then uses these measurements in balancing gasification reaction of the particles. INDEPENDENT CLAIMS are included for the following:    (1) generating syngas products for the solar-driven chemical plant involving: focusing concentrated solar energy to a solar driven chemical reactor contained within the solar thermal receiver; supplying biomass particles into at least one tube in the reactor; driving an endothermic gasification reaction of the particles of biomass flowing through the tubes by primarily heat radiation from inner walls of the receiver and tube surfaces of the reactor by the absorbed concentrated solar energy; balancing the gasification reaction with available concentrated solar energy and the additional variable parameters including a fixed range of particle size, operating temperature of the chemical reactor, and residence time of the particles in a reaction zone in the chemical reactor so that overall biomass particle conversion remains above a threshold set point of tar destruction resulting in less than or equal to 50 mg/Nm3 of tar and gasification of greater than 90% 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, where the 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 where 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; and    (2) method for a solar driven chemical plant, involving: 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, where an endothermic chemical reaction conducted in the reactor tubes includes at least one 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 C, preferably greater than 1000 degrees C.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of the entrained-flow biomass feed system.    Entrained-flow biomass feed system (600)    Rotating screw conveyor (602)    Grinding system (603)    Lock hopper system (604)    Lock hopper exit (606)