BACKGROUND
The inventi<»i relates generally to coal and biomass gasification systems and, more panicularhv to a system for iransporting solid particulate fuel to a gasifier that is most likely operated al high pressure.
In currenl commerciali/ed gasification systems, solid particulate fuel such as coal is fed into gasifier using either sluny feed or dr\' feed technologies. Due to the limitation in making sluny using high-moisture content solid particulate tuel, a dr>' feed system is normally ulili/ed to feed svKii solid particulate fuel into gasifiers. In exi.stin.g drj' feed sjstems, low rank coals may be drieti to remove two-thirds, or more, of the inherent moisture present in the coal. This improves tlte flow characteristics of the dried solids in the drv' feed system equipment and the overall effici^cs' of the gimfier. However, the overall power production of the plant is reduced since the dr>ing process consumes a large amount of OJergj.
In chemical, petrochemical, and power industries, most of the reactors such as gasifiers or corabistors are operated under high-pressure conditions. Feeding solid fuels or reactants into a high-pressure gasifier with a pressure range of about 100 to about UXX) psi is a significant challenge. In existing gasification systems, either a sluny feeding system or a lock-hopper drs' feeding sj'stem is used to feed solid fuels into a higlt-pressure gasifier. But, not all kinds of solid particulate fuels can be converted to sluro' with a fairly high solid concentration. Therefore, a slursy feeding system may not be suitable for all kinds of solid particulate fuels.
In lock-hopper drv- feeding s>'stem, solid fuels must be dried to a certain level to avoid rat-holing or bridging in the lock-hopper and reach a reasonable reliability. For example, browTi coal must be dried to a moisture-content of less than about 10 percent and bituminous coal must be dried to a moi.slure-content of less than

about 2 percent. However, existing dry feeding technologies may noi handle solid fuels witlioul pre-drv'ing to a certain level.
It would tlierefote be desirable to provide a dr\' feeding system that can feed solid particulate fuels with high nnoisture content into a high-pressure gasifier withow a pre-drying process.
BRIEF DESCRIPTION
In accordance witli one erabodiment disclosed herein, a system for ise in a gasification system comprises an increasing pitch screw feeder and a higli-pressure vessel disposed about said increasing {Htch screw feeder. The high-pressure vessel comprises an inlet for connection to an ortlei of a solid pump and a convej'ance gas line and an outlet through which fuel delivered from the solid pump is transported to a gasifier. The outlet is downstream of the .solid pump and the conveyance gas line.
In accordance v\ith another embodiment disclosed herem, a system for use in a gasification system, cooqjrises a solid pump for delivering a pressuri/xjd solid particulate fuel, a conveyance gas line, an increasing pitch screw feeder, a high-pressure vessel disposed about said increasing pitch screw feeder, and a flow line. The high-pressure vessel comprises an inlet for connection to an outlel of the solid pump and the convevance gas line and an outlet downstream of the solid pump and the first conveyance gas line. The flow line connects the outlet to a gasifier to transport the solid particulate fuel delivered from the solid pump to the gasifier.
In accordance with another embodiment disclosed herein, a sj'siem for use in a gasification system, wmprises a plurality of solid pumps for delivering a pressurized solid particulate fuel, a plurality of convejance gas tines, an increasing pitch screw feeder having a minimum pitch at an upstream end and a maximum pitch at a downirtrcam and, a high-pressure vessel disposed about said increasing pitch screw feeder, and a motor enclosed in the high-pressure vessel for driving the incresBing pitch screw feeder. The high-pressure vessel comprises a plurality of inlets for connecticm io a pluralitN' of solid pumps and at least one of tiie convevance gas
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lines and an outlet througlt which fuel ddjvered from the solid pump is transported to a gastfier. The outlet is downstream of the solid pumps and the con vey ajtice gas lines.
In accordance wiUt another embodiment disclosed herein, a system for use in a gasification system, comprises a plurality of solid pimips for delivering a pressurized solid particulate fud, a pluralitv- of conveyance gas lines, an increasing pitch screw feeder having an increasing pilch in the direction of a flow in the high-pressure vessel with a minimum pitch at an upstream end and a maximum pitdi) at a downstream end, a high-pressure vessel disposed about said increa.sing pitch screw feeder, a flow line, and a motor enclosed in the high-pressure vessel for driving the increasing pitch screw feeder. The high-pressure vessel comprises a plurality of inlets for connection to a pluralit>' of solid pumps and at least one of tlie conveyance gas lines and an outlet at said downstream end that is downstream of the solid pumps and the conve^'ance gas lines. The flow line connects tlie outlet to a gasifier to transport the solid particulate fuel delivered from the solid pump to the gasifier.
DR.AWINGS
These and other features, aspects, and advantages of the present inv«ition will become better mderstood when die following detailed description is read with reference to the accompanjing drawings in which like characters represent Uke parts throughout the drawings, wiierein:
FIG. 1 illustrates an embodiment of a feed transporting .system in accordance with aspects disclosed herein,
FIG. 2 iUiBtrates the feed transporting system that is installed below a gasifier in accordance with aspects disclosed herein.
FIG. 3 illustrates the increasing-pitch screw feeder in accordance with as{Tects disclosed herein.
FIG, 4 illustrates the feed transporting system that is installed above a gasifier in accordjuice with aspects disclosed herein.

DETAILED DESCKIFI ION
EiubodHJiaits disclosed hereio include a system for traiispoiting solid particulate fuel to a gasifier. TTie system mainly includes a screw feeder and a high-pressure vessel enclosing the screw feeder. Solid pumps and conveyance gas lines are connected lo inlets of the hi^-pressure vessel. The outlet of the high-pressure vessel is connected to a gasifier such as a gasifier or a combusfor. Fuel from the solid pumps enters the high-pressure vessel and transported to the outlet fa%' the screw feeder. Tl^e fuel is subsequently transported Ironi the outlet to the gasifier via a flow line. As tised herein, singular forms such as'%'' "an," and "tiie"' include plural referents unless the context clearly dictates otliervvise.
FIG, 1 illustrates m embodiment of the system 10 for transporting fuel to a gasifier. The system 10 includes an increasing pitch screw feeder 12, a high-pr^sure vessel 14 disposed about the screw feeder 12. solid pumps 16, and conveyance gas lines 18 and 20. The sj'Stem 10 is employed in gasification systems that use solid particulate fuel including, but not limited to, coal, biomass, pet coke, oil sand, heavy oil, md mixtures thereof In one embodiment, solids ptrnips a«j rotary, converging spstte Solids Transport ^d Metering pump utili/Jng Stamef""^ Posimetric® feed technology, otherwise known as a StametT^^ solids pump commercially available from GE Energy, Atlanta, GA Hiis pump is enable of transporting solids from atmospheric pressure to pressures well over 1000 psig with a slrongK' linear relationship between pump rotational speed and solids mass flow.
The screw feeder 12 is enclosed in the high-pressure vessel 14. The pitch of the screw feeder 12 is minimum at an upstream end 22 of the vessel and maximum at a downstream «id 24 of tlte vessel. Tlie s>'stem 10 further includes a motor 26 for driving the screw feeder 12. Tlie motor 26 is also enclosed in the high-pressimj vessel 14.
The high-pressure vessel has a pluralitj' of inlets 28 and an outlet 30. Each inlet 28 is connected to an outlet 32 of the solid pump 16 by pipelines 34, Conve\'ance gas lines 18 are in communication with the pipelines 34. A conveyance
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gas 35 is delivered through the conveyance gas lines 18 to eiiable deliver\- of solid particulate fuel 36 from the solid pump 16 to the high-pressure vessel 14. The system 10 also includes a dediciUed convwance gas line 20 that is dtrecih' connected lo an ixUet 28 of the high-pressure vessel 14 to enable transportation of fuel 36 to the oxrtJet 32 of the high-pi«ssure vessel 14. The outlet 32 is downstream of tlie solid pumps 16 and the conves-ance gas lines 18 and 20. Tlie pitch of the screw feeder 12 is jnjudraum at the outlet 32. The outlet 32 is connected to a flow line 38. The flow line 38 deliv«^ fuel to agasjfier.
ITie solid pumps 16 deliver pressurized solid particulate fuel 36 to the high-pressure vessel 14 via ttie pipelines 34. The solid particulate fuel 36 xmy include fuels such as, but not limited to, coal, biomass, p« coke, oil sand, hea\y oil, and mixtures thereof A high solid flow rate is achieved by connecting multiple solid pujnps 16 to the hig^-piessure vessel 14. The screw feeder 12, driven by the motor 26, transports the solid particulate fuel 36 to tlie flow line 38 via the outlet 32. Tlie pitch of the increasing pitch screw feeder 12 increases in the direction of a flow 40 in the vessel 14. Cwvev-ance gas 42 delivered through the dedicated convej'ance gas line 20 enables transmission of the solid particulate fuel 36 through the high-pressure vessel 14.
Referring to FIG. 2, conveyance gases 35 and 42 tnmsport the solid particulate fuel 36 to the injector 4f> of a gasifier 48 via the flow line 38. The flow line 38 is connected to the injector 4<>. In this embodiment, the ftiel transportation system 10 with the solid pumps 16 is located on the ground or below the gasitler 48. The convesance gases 35 and 42 aie introduced from l^elow the gasifier to carrv' the fuel 36 to itie iajeclor46,
TTie entire screw feeder 12 and the motor 26 are enclosed in the high-pressure vessel 14. This envies the system K) to be used under higher-pressure conditions. The system 10 mainuun.? operating pressure of more than the pressure in a gasifier such as a gasifier 48 or combustor to which the system 10 is connected in order to maintain a positive presstire diffa-enc^ with the gasifier. In one embodiment, tlve system 10 has an operating pressure of more than about 500 psig.
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Since the screw feeder 12 is enclosed in tlie Iiigh-pressure vessel 14 and tlie solid particulate fuel 36 is purged or carried b\' the conve>'ance gases 35 mid 42, no extra sealing is necessar>- for the ssstern H). The hig^-ptessure vessel 14 is pressurized bj- the convejance gases 35 and 42 flowing through the ctmvej'ance gas lines 18 aitd 20 to maintain a positive pressure difference versus the gasifier 48. This positive prffisure difference can avoid any syngas leakage from the gasifier 4K to the atmosphere through solid pumps 16. Also, the increasing pilch screw desi^ of the saew feeder 12 achieves iBiiform gas*$olid ratio during the mixing.
ITie l\iel transporting s\'stem 10 can be employed as a dr> feed sjslem in gasification plants that use solid particulate fuel with high moisture content. Solid fuel conve>'ance in the (low line is operated in transport regime, leading to a dense phase transport flow of solid fuel in the system. In the transport flow regime, all solid particulates from the same solid pump 16 have substantially the same residence time. The .solid pumps 16 can therefore be used as metering pumps in tliis s>'st«n due to tlie transport flow of solid fuel. Some potential problems such as particulate bridging and rat-holing due to the high moisture level in solid fuels can be avoided. Therefore, solid particulate fuels with higher moisture le\ el can be conves'ed to gasifier without any pre-dty. The solid particulate fud 36 is convened in transport flow regime, leading to a shorter residence time imid thus smaller volume for the vessel 14.
FIG. 3 illustrates the increasing pitch screw feeder 12. The screw feeder is connected to the motor 26. The screw feeder includes a shalt 50 and a screw thread 52 aroittid the shaft 50, A pitch of a screw can be defined as the distance between two consecutive screw threads. The screw feeder 12 is aji increasing pitch screw feeder in that the pitch between two consecutive threads increases in the direction of a flow in the vessel i.e. along the length of the screw feeder. The pitch is minimum at an upstream end 22 and gradually increases towards the downstream end 24. ITie pitch is maximum at the downstream end 24. For example, the pitch '"PI" at the upstream end 22 is the distance between first two consecutive threads and the pitch "Px" at the downstream end 24 is the distance between last two consecutive threads. The pitcli of the screw feeder 12, i.e. tlie distajiice between all pairs of consecutive threads, gradually increases from ''PI" to "Px." This distance is proportional to the solid flow
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at that location to maintain a uniform solid/'gas ratio over the screw feeder. Consequently, the solid flow rale as well as solid loading ratio in the tiansport line 38 is constant.
FIG. 4 illustrates another «Hnbodiment in which the fuel transporting svstem 10 with its solid pumps 16 is located above the gasifier 48 that is ~20{) feet from the ground. The flow line 38 connects the outlet 30 of the high-pressure vessel 14 to the injector 46 of fte gasifier 48. Conves'ance gases 35 and 42 are introduced from above the gasifier 48 to carrv' the fuel 36 dovsn to the injector 46.
The systems for triaisporting fuel to a gasifier described above thus provide a way to teed solid particulate fuels with high moisture level into high-pressure gasifiers such as a gasifier or a combustor witlioul any pre-dn- process, resulting in higher energy efficiencv. Tlie solid particulate fuel is transported in a plug-flow mode, leading to a smaller high-pressure vessel size and therefore reduced capital expenditure. The system can be used as a butter to minimixe the impact of the flow tluctuatiwi from different solid pumps. Also, the solid pumps employed in the system can be used as metering instrument, which increases the flexibility and controllability of the system. "I"he number of solid pumps and the increasing pilch screw can be selected based on tl»e desired solid fuel feeding rate.
It is to be understood that not necessarily all such objects or advantages desaibed above may be achieved in accordance with any particular eiTrfMxIimenl. Thus, for es:ample, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as tau^t herein without necessarily achieving other objects or advantages as ma>^ be taught or suggested herein.
While only certain features of the invenlion have been illustrated and desaibed herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood thai the appaided claims are intended to cover all such modifications and change as fall within the true spirit of the invention.

1. A system for use in a gasification s\'stem» comprising;
a pilch screw feeder, and
a high-pressure vessel disposed about said increasing pitch screw feeder, said high-pressure vessel comprising:
an inlet for connection to an outlet of a solid pump and a convev'ance gas line; and
an outlet through which fuel delivered from the solid pump is transported to a gasifier, the outlet is downstream of the solid pump and the conveyance g^ line.
2. The system of claim i, wherein a flow line connects the outlet to the gasifier to transport the fuel from the outlet to tlte gasifier.
3. The system of claim 1, wdierein the sj'stem is below the gasifier.
4. 1'he s>-stem of claim 1, wherein the system is above the gasifier.
5. The system of claim 1, wherein the fuel comprises a solid particulate fuel.
6. The system of claim ,5, wherein the solid pump is used as a metering pump.
7. The sjstem of claim 1, wherein tiie gasifier comprises a gasifier.
S. The SN'stem of claim 1. further comprises a motor for driving the increasing pilch screw feeder,
9. The system of claim 8, wiwrein the motor is enclosed in the high pressure vessel.

10. The s>'steni of claim i, wherein the pitch of the increasing pitch screw feeder inaeases in the direction of a flow in the vessel.
11. The system of claim 1, wherein the pitch of the increasing pitch screw feeder is maNimura at the outlet
12. The system of claim .1, wherein Ihe pitch of the metering pilch sc^rew feeder is minimum at an upstream end and maximum at a downsiream end.
13. A system for use in a gasification system, comprising;
a solid pump ibr delivering a prfssurixed solid particulate fuel;
a conveyance gas line;
an increasing pilch screw feeder;
a high-pressure vessel disposed about said increasing pilch screw feeder, said high-pressure vessel comprising:
an inlet for connection to att outlet of the solid pump and the conveyance gas line; and
an outlet downslTcam of ^e solid pump and the first conveyance gas line; and
a flow line coitnecting the outlet to a gasifier to transport the solid particulate fuel delivered from the solid pump to tlie gasifier.
14. The sj'stem of claim 13, wherein a conve\ imce gas is delivered through the flow line and the conveyance gas line.
15. The system of claim 13, wherein the high-pressure vessel is below the gasifier,
16. The system of claim 13, wherein the high-pressure vessel is above the gasifier.
17. The system of claim 13. further comprises a motor enclosed in the
\0

high-pressure vessel for driving the increasing pitch screw feeder
18. The SN'stem ofciaini 13. wlierein the pitch of the increasing pitch screw feeder increases in the direction of a flow in the vessel and is minimum at an upstream end and maximum at a downstream end.
19. The system of claim 13, wherein the pilch of the increasing pilch screw feeder is raaximura at the outlet.
20. A system for use in a gasification systwrj, comprising;
a plurality of solid pumps for dehveri.jig a pressurized solid fuel:
apiuralitj' of convej'^icegas lines;
an increasing pitch screw feeder having a minimum pitch at an upslream end and a maximum pilch at a doxvusiream end;
a high-pressure vessel disposed about said increasing pitch screw feeder, said high-pressure vessel comprising:
a pluralitj' of inlets for connection to a pturalily of solid pumps ^d at
least one of the conveyance gas lines; and
m outlet through which the solid fuel delivered from the solid pump is
transported to a gasifier, the outlet is downstream of the solid pumps and tlie
convey'ance gas lines; and
a motor enclosed in the high-pressure vessel for driving the increasing pitch screw feeder.
21. The s>stem of claim 20, wherein tlie system is below the gasifier.
22. The system of claim 2(X wherein the system is above the gasifier.
23. A system for use in a gasi.fication s>'stem, comprising:
a p!uralit>' of solid pumps for delivering a pressurized solid fuel; a plurality of comwance gas lines;
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an increasing pitch screw feeder having an increasing pitch in the direction of a flow in the high-pressure vessd with a minimum pitch at an upstream end and a niaximum pitch ai a downstream end;
a high-pressure vessel disposed about said increasing pitch screw feeder, said high-pressure vessel comprising:
a plurality of inlets for connection to a plurality of solid pumps and at
least one of the convev'ance gas lines; and
an outlet at said downstream end that is downstream of the solid pumps
and the conveyance gas lines;
a flow line connecting the outlet to a gasifier to transport ttie solid fuel delivered from the solid pump to the gasifier; and
a motor enclosed in the high-pressure vessel for driving the increasing pitch screw feeder.
24. The sj'stem of claim 23, wherein the high-pressure vessel is below the gasifier.
25. The s> stem of claim 23, wherein the high-pressure vessel is ^x>ve the gasifier.
''MANISHA SINGH NAIR ^^^, Agent for the Applicant [IN/PA-740J
LEX ORBIS
Intellectual Property Practice 709/710, Tolstoy House, 15-17, Tolstoy Marg, New Delhi-110001
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