PROCESS APPARATUS WITH OUTPUT VALVE AND OPERATION THEREOF

• US 20110011282A1
• Filed: 07/16/2010
• Published: 01/20/2011
• Est. Priority Date: 07/17/2009
• Status: Active Grant

• Current Assignee: Mascoma Canada Inc.
• Original Assignee: Sunopta Bioprocess Inc. (Lallemand Inc.)
• Inventors: Burke, Murray J.
• Granted Patent: US 8,443,724 B2
• Time in Patent Office: Days
• US Class Current: 100/35
• CPC Class Codes: B01J 2208/0007 Pressure measurement
• CPC Class Codes: B01J 2208/0061 Controlling the level
• CPC Class Codes: B01J 2208/00699 Moisture content regulation
• CPC Class Codes: B01J 2208/00752 Feeding
• CPC Class Codes: B01J 2219/00198 at the reactor inlet
• CPC Class Codes: B01J 2219/00231 at the reactor inlet
• CPC Class Codes: B01J 3/02 Feed or outlet devices therefor
• CPC Class Codes: B01J 8/002 with a moving instrument
• CPC Class Codes: B01J 8/0045 by means of a rotary device in the flow channel
• CPC Class Codes: B30B 11/241 Drive means therefor; screw bearings
• CPC Class Codes: B30B 11/265 with precompression means
• CPC Class Codes: C10L 5/44 on vegetable substances
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

An apparatus is provided for treating a loose fibrous solid organic feedstock. The apparatus includes a reactor vessel and a compressor operable to introduce feedstock at elevated pressure into the reactor chamber. The apparatus includes means for controlling and modulating moisture level within the reactor. The apparatus includes an outflow or discharge assembly that has its own feeder or drive for packing feedstock into a discharge accumulator. The discharge accumulator feeds an outflow valve, in this case a uni-directional rotation ball valve operated by a servo motor. Discharge from the valve may be carried through a diffuser into a settling cyclone. In operation the ball valve is rotated to open and close the outflow passageway, the rate of rotation being variable in real time. The rate of rotation may be a function of the pressure or other parameters sensed in the reaction vessel, and, particularly, in the accumulator immediately upstream of the ball valve, and of proxy sensed values such as discharge feeder motor current.

Claims

1. An apparatus for processing fibrous organic feedstock, said apparatus comprising:

a compressor operable to raise the fibrous organic feedstock to a processing pressure;

a reactor vessel through which to process the fibrous organic feedstock under pressure;

a discharge assembly mounted to receive the fibrous organic feedstock of the reactor vessel;

said discharge assembly including a collector and a drive member operable to pack the fibrous organic feedstock into the collector;

an outflow governor mounted to the collector, the outflow governor being movable between a closed position for retaining feedstock in the collector and an open position for permitting egress of the feedstock from the collector;

said outflow governor having an outflow governor drive;

said outflow governor drive having a continuously variable speed control; and

said speed control is operable to alter both the duration of the outflow governor in the open position and the ratio of time spent in the open and closed positions.

2. The apparatus of claim 1 wherein the variable speed control is operable to cycle the outflow governor between open and closed conditions in excess of 40 times per minute.

3. The apparatus of claim 1 wherein the apparatus includes at least one of:

(a) sensors operable to monitor pressure upstream of said outflow governor and said controller is connected to cause operation of said outflow governor in response to pressure signals; and

(b) sensors to monitor feedstock load in the collector, and said controller is connected to cause operation of said governor in response to load sensed in the collector.

4. The apparatus of claim 1 wherein said apparatus includes at least one heat transfer interface at which heat may be added to said reactor vessel and any contents thereof.

5. The apparatus of claim 1 wherein said apparatus includes at least one moisture modification input by which to modulate moisture level within said reactor vessel.

6. The apparatus of any of claims 1 wherein said outflow governor is a ball valve.

7. The apparatus of claim 6 wherein said outflow governor drive is a motor mounted to turn said ball valve continuously in one direction.

8. The apparatus of any of claims 1 wherein said apparatus includes at least one of

(a) a diffuser connected to receive outflow from said outflow governor;

and

(b) a cyclone is connected downstream of said outflow governor.

9. The apparatus of claim 1 wherein said outflow governor is connected to open in response to presence of feedstock in the collector and sensing of a minimum outflow pressure threshold.

10. The apparatus of claim 1 wherein said controller has control logic to do any one of:

(a) shorten outflow governor closed time when resistance to packing of the outfeed collector increases;

(b) lengthen outflow governor open time when resistance to packing of the outfeed collector increases;

(c) increase the ratio of outflow governor open time to outflow governor closed time as proportions of total outflow governor cycle time;

(d) bias said outflow governor to reduce outflow open time to a minimum threshold value; and

(e) immediately to move said outflow governor to the closed position when pressure upstream therefrom falls below a designated set point value.

11. A process for treating a loose fibrous feedstock, said process comprising:

establishing the loose fibrous feedstock in a reactor vessel at an elevated pressure relative to ambient;

passing charges of said feedstock through a sudden expansion; and

controlling decompression cycle parameters in real time with a variable speed outflow valve.

12. The process of claim 11 wherein said process includes using a ball valve as said variable speed outflow valve.

13. The process of claim 12 wherein said process includes driving said ball valve uni-directionally and varying speed in that one direction.

14. The process of claim 11 wherein said process includes employing sensors to observe pressure in the reactor vessel upstream of the outflow valve, and modulating operation of the outflow valve in response to pressure sensed upstream of the outflow valve.

15. The process of claim 11 wherein said process includes at least one of:

(a) maintaining said outflow valve in an open condition for less than one second;

(b) maintaining said outflow valve in an open condition for t_Open, and maintaining the outflow valve in a closed condition for t_Closed where t_Open is less than ¼

of t_Closed;

(c) sensing pressure drop upstream of the outflow valve while the outflow valve is open, and driving the outflow valve closed immediately if pressure drop exceeds a set threshold value, P_Dropref;

(d) sensing presence of feedstock in a collector mounted upstream of the outflow valve, and inhibiting opening of the outflow valve unless feedstock is inferred to be present;

(e) setting a minimum open condition time reference value, t_Ref, for the outflow valve, and biasing the opening time of the outflow valve, t_Open, toward t_Ref;

(f) opening and closing the outflow valve in the range of 20 to 120 times per minute.

16. The process of claim 11 wherein the process includes at least one of:

(a) opening and closing the outflow valve at least 40 times per minute;

(b) maintaining a total cycle time, t_total, of less that 2 seconds, where t_total is the sum of valve open time, t_Open, and valve closed time, t_Closed;

(c) maintaining a ratio of valve open time, t_Open, and valve closed time, t_Closed that is less than 1;

5.

17. The process of claim 15 wherein the process includes all of (a) to (f).

18. The process of claim 16 wherein the process includes all of (a), (b) and (c).

19. The process of claim 11 wherein the process includes:

providing a feedstock collector upstream of the outflow valve;

providing a drive to pack feedstock into the collector;

monitoring drive motor electrical current;

monitoring pressure immediately upstream of the outflow valve;

inhibiting opening of the outflow valve until drive motor electrical current exceeds a threshold current value, I_valveopen, and reactor pressure immediately upstream of the outflow valve is at least as great as a pressure minimum discharge triggering value, P_valve open;

closing said valve at the earliest of;

(a) timing out against a set reference value, t_Long;

(b) sensing a drop in electrical motor current to below a set reference value I_Lowref;

(c) sensing a drop in pressure greater than a set reference value P_Dropref.

20. The process of claim 19 wherein said process includes biasing the outflow valve open time t_Open period to the shortest period of time consistent with the conditions of claim 19.

21. The process of claim 20 wherein said process includes biasing the ratio of outflow valve open time, t_Open, to outflow valve closed time, t_Closed, to the minimum value consistent with the conditions of claim 20.

22. The process of claim 11 wherein the process includes heating the feedstock in the reaction chamber to a temperature corresponding to saturated water vapour temperature at the pressure of the reactor chamber.

23. The process of claim 11 wherein the process includes maintaining a moisture level within the reaction chamber in a preset range.

24. The process of claim 11 wherein the loose fibrous feedstock is loose fibrous solid organic feedstock, and a ratio of valve open time, t_Open, to valve closed time, t_Closed, falls in the range of 3:

1 and 10;

1.

25. The process of claim 11 wherein the loose fibrous feedstock is loose fibrous solid organic feedstock, and a ratio of valve open time, t_Open, to valve closed time, t_Closed, falls in the range of 5:

1 and 8;

1.

26. The process of claim 11 wherein the control valve is a ball valve having a mean rotation speed giving a valve open frequency in the range of 30 to 60 Hz.

27. The process of claim 11 wherein there is an outfeed charge container and a motorized drive operable to pack feedstock into the outfeed charge container the control valve has a control valve motor, the motorized drive has a full load electrical current, I_fl, the outflow valve is inhibited from opening when the current draw is less than 70% of I_fl, and the outflow valve is inhibited from closing when I_fl, is greater than 50% of I_fl.

28. The process of claim 11 wherein the process has a target control valve time open, t_Open, of less than ½

second.

29. The process of claim 11 wherein the reactor vessel is maintained at a pressure in excess of 190 psig, and temperature in the reactor vessel is maintained at the corresponding steam table saturated temperature.

30. The process of claim 29 wherein the target reactor vessel pressure is 245 psig +/−

5 psig.

31. The process of claim 11 wherein control valve closing is initiated on a fall in pressure of 2 psig, and is immediate on a fall in pressure of 5 psig.

32. The process of claim 11 including maintaining a moisture level in the feedstock of 35 to 55% by weight at the state of entry of the feedstock into the reactor vessel.

33. The process of claim 11 wherein said process includes passing the feedstock from said control valve through at least one of (a) a diffuser;

and (b) a cyclone.