Horizontally-oriented gasifier with lateral transfer system
A method and apparatus is described for the efficient conversion of carbonaceous feedstock including municipal solid waste into a product gas through gasification. More specifically, a horizontally-oriented gasifier having one or more lateral transfer system for moving material through the gasifier is provided thereby allowing for the horizontal expansion of the gasification process such that there is sequential promotion of feedstock drying, volatization and char-to-ash conversions.
1. A horizontally-oriented gasifier comprising:
a horizontally-oriented, gasification chamber comprising three or more steps, one or more feedstock inputs, one or more gas outlets and a solid residue outlet;
a chamber heating system comprising three or more independently controlled air boxes, wherein each step is provided with an independently controlled air box for each step of the three or more steps;
three or more lateral transfer units for moving material through the gasification chamber during processing; wherein each step is provided with a lateral transfer unit and wherein each lateral transfer unit comprises a ram configured to push reactant material along and over a step;
one or more pile height sensors operatively associated with the gasification chamber;
and a plurality of temperature sensors operatively associated with the gasification chamber; and
a control system configured to receive signals from the one or more pile height sensors and configured to control the sequence of ram movement, speed of each ram, and the distance each ram moves in response to the signals from the one or more pile height sensors;
the control system further configured to receive signals from the plurality of temperature sensors and control air flow from the independently controlled air boxes to provide three or more laterally distributed regional temperature zones in response to the signals from the one or more temperature sensors, wherein a first regional temperature zone has a temperature that promotes drying, a second regional temperature zone has a temperature that promotes volatization and a third regional temperature zone has a temperature that promotes char-to-ash conversion.
2. The horizontally-oriented gasifier of claim 1 , wherein the control system is configured to implement feedback control schemes.
3. The horizontally-oriented gasifier of claim 1 , wherein the gasifier has three steps and each zone substantially corresponds to a step.
4. The horizontally-oriented gasifier of claim 1 , wherein the control system comprises:
A. one or more sensing elements configured to sense one or more characteristics of a process, a process device, a process input and/or process output;
B. one or more response elements configured to affect one or more characteristics of one or more processes within the system; and
C. one or more computing platforms operatively associated with one or more of the sensing elements and one or more of the response elements, the one or more computing platforms configured to receive input signals from at least one sensing element and to provide control signals to at least one response element to either maintain or adjust a process characteristic within the system.
5. The horizontally-oriented gasifier of claim 1 , wherein the pile height sensors are level switches.
6. The horizontally-oriented gasifier of claim 1 , wherein the air boxes are configured to provide hot air to the base of the reactant pile.
7. The horizontally-oriented gasifier of claim 1 , wherein at least one of the gas outlets is operatively associated with a gas reformulating system, a gas refinement system or a cyclonic oxidizer.
8. The horizontally-oriented gasifier of claim 1 , wherein the control system is configured such that air flow to each step is pre-set to maintain substantially constant temperature ranges and ratios between steps.
9. The horizontally-oriented gasifier of claim 1 , wherein each lateral transfer unit comprises an externally mounted controller thereby providing independent control of each lateral transfer unit.
10. The horizontally-oriented gasifier of claim 1 , wherein each of the individual lateral transfer units comprises one or more guide elements and/or one or more alignment elements.
11. The horizontally-oriented gasifier of claim 1 , comprising one or more process additive inputs.
12. The horizontally-oriented gasifier of claim 11 , wherein the one or more process additive inputs are configured for inputting one or more of steam, air, oxygen-enriched air, an oxygen source and/or a carbon-rich additive into the gasifier.
13. The horizontally-oriented gasifier of claim 2 , wherein the system is integrated into a gasification facility and the heating system utilises heat recovered from one or more locations within the gasification facility.
14. The horizontally-oriented gasifier of claim 1 , wherein the horizontally-oriented gasifier comprises a controllable residue removal means.
15. The horizontally-oriented gasifier of claim 14 , wherein the controllable residue removal means comprises a ram mechanism, a system of conveying rams, or a rotating arm mechanism to push residue comprising ash out of the gasifier.
16. The horizontally-oriented gasifier of claim 1 , operatively associated with a solid residue conditioning system and a plasma refinement system.
17. The horizontally-oriented gasifier of claim 1 , wherein the air boxes are configured to provide hot air through the floor of the gasifier.
18. The horizontally-oriented gasifier of claim 1 , wherein each step is operatively associated with at least one pile height sensor.
19. The horizontally-oriented gasifer of claim 1 , comprising proximity or position sensors and wherein the ram stokes are controlled in part by signals from said proximity or position sensors.
20. The horizontally-oriented gasifier of claim 1 , wherein each ram is a multiple-finger ram.
21. The horizontally-oriented gasifer of claim 20 , wherein each lateral transfer unit is configured such that the ram can be fully or partially withdrawn from the gasification chamber.