DESC:SYSTEM AND METHOD FOR PRODUCING HYDROGEN RICH SYNGAS FOR HYDROGEN GENERATION ,CLAIMS:1. A process (100) for producing hydrogen-rich syngas by biomass gasification, comprising:
• determining a height above a fixed bed in a downdraft gasifier (200) for introduction of one of oxygen and oxy-steam mixture in the downdraft gasifier (200), wherein the height is based on mass-flux of biomass, diameter of biomass particles, temperature of the one of oxygen and oxy-steam mixture, and thermal diffusivity;
• charging biomass through a lock-hopper (206) into the downdraft gasifier (200);
• introducing the oxy-steam mixture in the downdraft gasifier (200) at the height determined;
• igniting the biomass; and
• collecting the hydrogen-rich syngas from the downdraft gasifier (200), wherein mass-flux of the biomass is varied in a range of 0.05-0.11 kg/m2s to control a flame propagation rate (FPR) in the downdraft gasifier (200).
2. The process (100) as claimed in claim 1, wherein the process (100) comprises pre-mixing oxygen and superheated steam prior to introducing the oxy-steam mixture in the downdraft gasifier (200).
3. The process (100) as claimed in claim 1, wherein a ratio of oxygen to super-heated steam in the oxy-steam mixture increases with increase in mass flux of biomass.
4. The process (100) as claimed in claim 1, wherein a ratio of oxygen to super-heated steam in the oxy-steam mixture is in a range of 1:50 to 1:150 (on mass basis).
5. The process (100) as claimed in claim 1, wherein the FPR is in a range of 0.05 mm/s-0.15 mm/s.
6. The process (100) as claimed in claim 1, wherein the hydrogen-rich syngas comprises hydrogen to carbon monoxide ratio in a range of 1-3.9.
7. The process (100) as claimed in claim 1, wherein the process (100) comprises introducing superheated steam at least one of a plurality of elevations in addition to the oxy-steam mixture.
8. The process (100) as claimed in claim 1, wherein the process (100) comprises scrubbing the hydrogen-rich syngas to purify the gas.
9. The process as (100) claimed in claim 1, wherein the biomass comprises moisture in a range of 0-50%.
10. The process (100) as claimed in claim 1, wherein the relevant ambient temperature for water gas shift reaction to proceed in the forward direction is greater than 750K.
11. The downdraft gasifier (200) to perform the process (100) as claimed in any of the preceding claims comprising:
• a gasification chamber (202) comprising an inlet (204) at a top end of the gasification chamber (202) for charging of the biomass, wherein the inlet (204) is coupled to a lock-hopper (206);
• a plurality of inlets (208a, 208b) at the plurality of elevations along a wall (210) of the gasification chamber for introduction of the oxy-steam mixture and the superheated steam into the gasification chamber (202);
• an ignition nozzle (212) at a bottom end of the gasification chamber (202) for igniting the biomass; and
• an outlet (214) at the bottom end of the gasification chamber (202) for collecting the hydrogen-rich syngas generated in the downdraft gasifier,

wherein the outlet is substantially below the ignition nozzle (212), wherein the downdraft gasifier (200) has a turn-down ratio in a range of 1:3 to 1:4.