HK1158250B - An apparatus, components and operating methods for circulating fluidized bed transport gasifiers and reactors - Google Patents

Abstract

The improvements proposed in this invention provide a reliable apparatus and method to gasify low rank coals in a class of pressurized circulating fluidized bed reactors termed "transport gasifier." The embodiments overcome a number of operability and reliability problems with existing gasifiers. The systems and methods address issues related to distribution of gasification agent without the use of internals, management of heat release to avoid any agglomeration and clinker formation, specific design of bends to withstand the highly erosive environment due to high solid particles circulation rates, design of a standpipe cyclone to withstand high temperature gasification environment, compact design of seal-leg that can handle high mass solids flux, design of nozzles that eliminate plugging, uniform aeration of large diameter Standpipe, oxidant injection at the cyclone exits to effectively modulate gasifier exit temperature and reduction in overall height of the gasifier with a modified non-mechanical valve.

Description

Apparatus, components and methods of operation for circulating fluidized bed transport gasifiers and reactors

Cross Reference to Related Applications

This application claims benefit of U.S. provisional application No. 61/288,533 filed on 21/12/2009, 61/288,533, which is hereby incorporated by reference.

Statement regarding federally sponsored research or development

The invention was made with government support under cooperative agreement No. DE-FC21-90MC25140 awarded by the U.S. department of energy. The united states government has certain rights in the invention.

Technical Field

The present invention relates generally to pressurized circulating fluidized bed transport reactors (pressurized circulating fluidized bed transport reactors), and more particularly to various components in transport gasifier loops.

Background

Of the various Gasification technologies seen in the book by highman and van de Burgt (Gasification, 2003, Elsevier), it becomes apparent that new technologies are desired to improve the economics of gasifying low-rank coals, particularly coals with high moisture and/or ash content such as lignite or subbituminous coals.

Entrained flow gasifiers (entrained flow gasifiers) use a dry feed system or a slurry feed system to feed coal having a particle size of less than 75 microns. For a dry feed process, the coal moisture must be less than 5% to prevent coal particles from forming a cake and bridging in the feed system, particularly in the lock vessel (lock vessel) of the feed system. For slurry feed systems, about 35wt.% water must be added to make the coal slurry. It is necessary to dry the coal to a very low moisture level prior to making the slurry to avoid having a total moisture in the slurry of greater than 40%. Typically, low rank coals contain greater than 30% moisture; drying coal to less than 5% moisture requires expensive drying facilities with high operating costs, thereby reducing overall process efficiency. It is highly desirable to reduce drying tasks and operational concerns when processing low rank coals.

U.S. patent No. 6,631,698 discloses a circulating fluidized bed reactor that can be used for gasifying low-rank coals. However, the plant can only be used in atmospheric applications and requires a large footprint (foot-print) to produce the large amount of synthetic fuel required by modern plants or power plants in which coal gasifiers are installed.

U.S. patent No. 5,560,900 discloses a process based on a pressurized circulating fluidized bed reactor that is also intended to partially oxidize low rank coals. This concept proposed for the treatment of coal is based on the experience of the low pressure Fluid Catalytic Cracking (FCC) process in the petroleum industry for more than fifty years. Thus, the reactor system, as already disclosed, uses a riser (riser) since the pyrolyzer with the large amount of heat necessary for the pyrolysis reaction is carried along by finely divided refractory material circulating around the reactor loop. How to separate the coal ash generated from the heat-carrying materials in the process is one of the difficult problems to deal with and this patent circumvents this problem. Furthermore, the reactor has a mixing zone below the pyrolysis zone, the diameter of which is much larger than the riser diameter, to ensure sufficient residence time to heat the coal particles fed into the mixing zone. The minimum gas velocity necessary to entrain circulating solid particles from the mixing zone makes the gas velocity in the transport riser unusually high, resulting in rapid corrosion of any internals such as thermowells and corrosion of the cyclone walls. Furthermore, since the pyrolysis reaction requires a much longer residence time for completion and prevents the formation of tar in the product syngas (syngas), the riser must be impractically high in an industrial process for the reactor proposed in the patent. Furthermore, the process does not teach how to properly distribute the gas (steam and air or oxygen) over the cross section of an industrial scale gasifier.

Moving bed gasifiers have been used to gasify low rank coal for over 100 years. In particular, Lurgi gasifiers have been widely used to produce synthesis gas for chemical synthesis. However, moving bed gasifiers require lump coal as a feed and cannot utilize fine coal fines that are abundant but often have few users in their vicinity. Another disadvantage of this technique is that much of the coal is converted to tar rather than useful syngas.

Furthermore, all of these gasifiers have complex internal parts. Moving bed gasifiers have a precision rotating grid system and a stirring mechanism as internal parts for briquetting the coal. Fluidized bed gasifiers have various types of complex internal gasifying agent distributors made of rare alloys to withstand gasifier operating temperatures up to 1100 ℃. Despite the considerable efforts in designing distribution grids and selecting expensive superalloy materials, these grids still suffer from commercially unacceptable failures. In the case of entrained flow gasifiers, the most problematic internal part is the coal burner, which is one of the components that requires the highest maintenance intensity in the process.

Summary of The Invention

The present invention provides an improved apparatus for the gasification of a variety of circulating fluidized bed applications, including low rank coals such as lignite and subbituminous coals.

The present invention provides a reliable apparatus and method for gasifying low rank coal in a pressurized circulating fluidized bed reactor of the type known as a transport gasifier.

The invention provides a transport gasifier circuit comprising:

a lower mixing zone coupled to a lower gas inlet section, the lower mixing zone configured to receive at least one gasification agent through the lower gas inlet section;

an upper mixing zone coupled to the lower mixing zone, the upper mixing zone including an upper gas inlet portion configured to receive a mixture of circulating solids and the at least one gasification agent, the upper mixing zone further coupled to a solids feeder;

a riser coupled to the upmixing zone, the riser configured to receive the mixture of circulating solids, the at least one gasifying agent, and gaseous products from the upmixing zone, the riser further comprising an elbow coupling the riser to an inclined transition joint, wherein the gaseous products result from a reaction between the mixture of circulating solids and the at least one gasifying agent;

a pre-salinator cyclone coupled to the inclined transition joint, the pre-salinator cyclone configured to separate solid particles from the gaseous product;

a seal tube coupled to a lower portion of the pre-salinator cyclone, the seal tube configured to receive solids from the pre-salinator cyclone;

a riser cyclone coupled to an output of the pre-salinator cyclone, the riser cyclone configured to separate finer particles from the gaseous product; and

a riser coupled to the loadlock pipe, the riser cyclone, and the pre-salinator cyclone, the riser configured to receive solid particles from the pre-salinator cyclone and the finer particles from the riser cyclone through the loadlock pipe, the riser further configured to recirculate the mixture of circulating solids to at least one of the downmixing zone and the upmixing zone.

The transport gasifier circuit may further comprise: an aeration distribution assembly coupled to the standpipe and configured to facilitate recirculation of a mixture of the circulating solids from the standpipe to a non-mechanical valve, wherein the aeration distribution assembly can be located about six inches to eighteen inches below the non-mechanical valve.

The transport gasifier circuit may further comprise: a non-mechanical valve configured to couple the riser to a lower mixing zone and the upper mixing zone, the non-mechanical valve further configured to reduce a reverse flow of gaseous material into the riser.

The transport gasifier circuit may further comprise: an oxidant inlet coupled to an outlet of at least one of the presaltor cyclone and the riser cyclone, the oxidant inlet configured to receive an oxidant.

In the transport gasifier circuit provided, the lower gas inlet portion may further comprise: a spray throat coupled to a U-shaped refractory lined pipe, the U-shaped refractory lined pipe also coupled to an inlet of the lower mixing zone.

In the transport gasifier circuit provided, the horizontal portion of the U-shaped refractory lined pipe may have a length of about four to eight times an inner diameter of the U-shaped refractory lined pipe.

In the transport gasifier circuit provided, the lower mixing zone may have a diameter at least equal to at least one of the upper mixing zone and the riser.

In the transport gasifier circuit provided, the upper gas inlet portion may further comprise: a plurality of nozzles configured to inject carbonaceous material, the nozzles oriented at a downward angle of about fifteen to seventy-five degrees relative to a horizontal reference line.

In the transport gasifier circuit provided, the upper gas inlet portion may further comprise: a plurality of nozzles configured to inject the at least one gasification agent into the upmix zone, wherein a distribution of the at least one gasification agent produces a substantially uniform heat release.

In the transport gasifier circuit provided, the upper gas inlet portion may further comprise: a plurality of nozzles configured to have a gas flow direction upward into the transport gasifier circuit, the nozzles having a downward nozzle connected to a gas source at a first end and an upward nozzle into the transport gasifier circuit forming a T-joint at a second end; wherein a distance between the T-joint and a nozzle outlet into the transport gasifier circuit is about four to eight times an inner diameter of the upward nozzle.

In the transport gasifier circuit provided, the charge seal pipe may further comprise: a charge seal tube riser having a height of about twelve inches to thirty-six inches.

In the transport gasifier circuit provided, the charge seal pipe may further comprise: a downcomer coupled to an output of the pre-salinator cyclone and an input of the blanking pipe, the downcomer configured to receive solids from the pre-salinator cyclone, the downcomer further configured to maintain a minimum solids level.

In the transport gasifier circuit provided, the riser cyclone may further comprise a vortex finder supported by an expansion circuit attached to an outer shell of the riser.

In the transport gasifier circuit provided, the non-mechanical valve may further comprise: a short L-leg configured to provide a solid seal against the counter flow of gas, and a long J-leg.

The present invention also provides a method of using a transport gasifier circuit comprising: a lower mixing zone coupled to a lower gas inlet section, the lower mixing zone configured to receive at least one gasification agent through the lower gas inlet section; an upper mixing zone coupled to the lower mixing zone, the upper mixing zone including an upper gas inlet portion configured to receive a mixture of circulating solids and the at least one gasification agent, the upper mixing zone further coupled to a solids feeder; a riser coupled to the upmixing zone, the riser configured to receive the mixture of circulating solids, the at least one gasifying agent, and gaseous products from the upmixing zone, the riser further comprising an elbow coupling the riser to an inclined transition joint, wherein the gaseous products result from a reaction between the mixture of circulating solids and the at least one gasifying agent; a pre-salinator cyclone coupled to the inclined transition joint, the pre-salinator cyclone configured to separate solid particles from the gaseous product; a seal tube coupled to a lower portion of the pre-salinator cyclone, the seal tube configured to receive solids from the pre-salinator cyclone; a riser cyclone coupled to an output of the pre-salinator cyclone, the riser cyclone configured to separate finer particles from the gaseous product; and a riser coupled to the loadlock pipe, the riser cyclone, and the pre-salinator cyclone, the riser configured to receive solid particles from the pre-salinator cyclone and the finer particles from the riser cyclone through the loadlock pipe, the riser further configured to recirculate the mixture of circulating solids to at least one of the downmixing zone and the upmixing zone, the method comprising:

controlling solids level and flow rate into the riser by controlling particle size of solids input through the solids feeder and discharge of coarse ash from the transport gasifier circuit.

The method may further comprise the steps of: maintaining a substantially uniform temperature in the transport gasifier loop by circulating the solids.

In the method provided, the solids may be circulated at a rate of about one hundred to four hundred pounds per square foot per second.

The method may further comprise the steps of: the at least one gasification agent is uniformly distributed between the upper mixing zone and the lower mixing zone.

The method may further comprise the steps of: the at least one gasification agent is supplied to the lower mixing zone through a jet distributor at a throat velocity of about fifty to three hundred ft/s.

The method may further comprise the steps of: adjusting a gasifier outlet temperature by injecting an oxidant at an outlet of at least one of the pre-salinator cyclone and the riser cyclone.

Embodiments of the present invention overcome the above-described problems of prior art gasifiers. The transport gasifier loop includes a gasifying agent distribution system, a mixing zone, a riser, a first stage cyclone known as a presaltor cyclone, a second stage cyclone known as a riser cyclone, a charge seal pipe for returning solids collected in the presaltor cyclone to the riser, and a non-mechanical valve for moving solids from the riser to the mixing zone while substantially reducing or preventing reverse flow of gases.

The gasifying agent supply system according to the embodiment of the present disclosure can be implemented with little or no internals (internal). The distribution system may substantially reduce or prevent backflow of hot solids. The movement of solid particles inside the gasifier aids uniform distribution of the gasification agent throughout the cross-section of the gasifier.

Embodiments of the transport gasifier may also include nozzles that supply gas into the gasifier by a mechanism that substantially reduces or prevents nozzle blockage when the gasifier is suddenly shut down for process or safety reasons. Solids settling in the nozzle during shut-down can simply be blown back into the gasifier when gas flow to the nozzle is resumed. Thus, the transport gasifier nozzle can be prevented from being clogged.

Transport gasifiers according to embodiments of the present disclosure may also employ a first stage presaltor cyclone that can separate high loadings of solids in the carrier gas and substantially reduce or prevent corrosion of the cyclone walls by such high solids loadings. Furthermore, compared to prior art cyclones, the pre-salinator cyclone in the first stage according to embodiments of the present disclosure may be employed without a vortex finder and without a roof (roof). These concepts can reduce the reliability problems encountered in industrial high pressure, high temperature first stage cyclone designs, operation and long term operation.

Solids collected by the pre-salinator cyclone may flow through a lock pipe to the riser. The location and design of the seal pipe in various embodiments of the transport gasifier takes advantage of the natural pressure gradient to minimize gas addition to the seal pipe and the gasifier loop.

The riser cyclone may collect particles from the gas stream, and then the fine solids collected by the riser cyclone may be combined with the solids collected by the pre-salinator cyclone and returned to the riser through the riser. Embodiments of the transport gasifier may reduce or avoid flowability problems associated with the fine solids as they flow down the riser. In addition, the present invention facilitates the mixing of finer solids with the coarse solids collected by the pre-salinator cyclone as they flow through the seal pipe to the riser.

In various embodiments of the present disclosure, certain of the gasification agent, oxygen, and/or air, along with steam, may be injected at the outlet of the first or second stage cyclone to increase the gas outlet temperature and reduce the carbon content in the fly ash. Gasification agent injection can also reduce the methane content and increase the carbon monoxide and hydrogen content in the product gas.

The transport gasifier according to embodiments of the present disclosure also allows for a more optimized configuration of the location of the aeration nozzles (aerationnozzles) in the riser relative to the prior art. For large scale industrial applications, aeration gas (aeration gas) may be employed in or near the bottom of the large diameter riser so that the aeration gas can be distributed and facilitate the flow of solids from the riser to the riser through the non-mechanical valve.

In one embodiment, the bulk density in the riser may be in the range of about 5 to 20lb/ft³Within the range of (1). In one case, the mass ratio of recycled solids to feed (feedstock) can also be between about 50 and 200. This wide range is beneficial for optimizing the design and operation of feeds with different coal characteristics.

The transport gasifier provides a method for controlling solids levels in the riser and operating the gasifier at high desired solids throughput and riser density and at a sustained high solids circulation rate in the loop, resulting in significant improvements to coal to syngas conversion at maximum syngas production rates.

Brief Description of Drawings

FIG. 1 is a schematic representation of a transport gasifier circuit.

FIG. 2 is a schematic representation of a gas distributor as part of a lower mixing zone through which a portion of the gasification agent is introduced into the gasifier.

FIG. 3 is a representation of the lower mixing zone, the upper mixing zone, the lower portion of the riser, and the non-mechanical valve inlet to the gasifier mixing zone, along with the coal injection nozzle and feed gas distribution, to manage heat release and achieve uniform and rapid heating of the coal particles.

Fig. 4 is a schematic representation of a riser bend connecting the riser and an inclined crossover joint through which salt-precipitated (salted out) solids in the gas stream enter the pre-salinator cyclone tangentially.

FIG. 5 is a schematic representation of a charge seal pipe connecting the pre-salinator cyclone to the riser.

FIG. 6 is an illustration of a typical aeration nozzle design for gas flow in an upward direction into a transport gasifier.

FIG. 7 is a schematic representation of a riser cyclone designed to withstand the high pressure, high temperature, and corrosive environment of a transport gasifier.

FIG. 8 is a graphical representation of oxidant injection at the cyclone outlet to effectively adjust the gasifier outlet temperature and slightly improve overall carbon conversion.

FIG. 9 is a schematic representation of an aeration distributor for a large diameter transport gasifier riser.

FIG. 10 is an illustration of an L + J non-mechanical valve concept for reducing the overall height of a transport gasifier.

Detailed description of the embodiments

Various embodiments and illustrations of a transport gasifier circuit according to embodiments of the present disclosure are described by way of example and illustration. Fig. 1 illustrates a transport gasifier circuit 100. The gasifier vessel wall may be made of carbon steel and the shell may also constitute the pressure boundary of the gasifier. Gasifier loop 100 may be operated at a pressure between about 100 and 1000psia, depending on the process requirements of the unit utilizing the syngas obtained downstream. Inside the shell of the gasifier circuit 100, there may be two layers of refractory lining. The inner layer in contact with the circulating bed of solids may comprise a layer of corrosion resistant refractory material to protect the soft insulating refractory material and the vessel walls. The outer insulation layer may be in contact with the shell of the gasifier circuit 100 on one side and the corrosion resistant refractory material on the other side. The insulating refractory protective shell is not overheated. An embodiment of the transport gasifier circuit 100 can include a gas distributor near the bottom of the gasifier, a lower mixing zone, an upper mixing zone, a riser, an incline transition joint, a first stage (pre-salinator) cyclone, a second stage riser cyclone, a riser, a seal pipe connecting the pre-salinator cyclone and the riser, and a non-mechanical valve connecting the riser and the mixing zone, which will be described in additional detail herein.

Fig. 2 is a schematic representation of a Lower Mixing Zone (LMZ) 200 of a transport gasifier loop 100, with about 25-100% of the gas (e.g., air, oxygen, and/or steam) for the gasification reaction being injected through the lower mixing zone 200, according to an embodiment of the present disclosure. The characteristics of the feed determine the amount of gas that needs to be injected into the LMZ, and the remainder can be distributed along the height of the mixing zone (e.g., both the lower mixing zone and the upper mixing zone). In the embodiment shown in FIG. 2, the LMZ200 includes a jet gas distributor or gas inlet portion 225. About 70% -95% of the gas entering the LMZ may be injected into the distributor section through the nozzle inlet 210. The remaining 5% to 30% of the gas injected into the LMZ may be supplied through a plurality of nozzles 270 located at various heights along the conical portion 240 of the distributor. The number, orientation, and height of the nozzles may vary depending on the type of feed and gasifier size, as may be appreciated. Collectively, the gas flowing through the gas inlet section 225 and the nozzles 270 provide a means for introducing and distributing the gasification agent throughout the entire cross-section of the gasifier without any internals.

The nozzle inlet 210 is delimited by a refractory-lined tube (refractory-lined pipe) that passes the gas from its source, using a metal pipe for the gas distributor. The U-shaped refractory lined tube in the embodiment shown in fig. 2 has a vertical part 215 through which the gas flows downwards and which is connected to a horizontal part 220, and another vertical part 230 through which the gas flows upwards towards the throat before entering the conical part of the distributor. All of these parts may be made of refractory lined pipes. When the gasifier is shut down for safety or process reasons, solids that are retained in the gasifier mixing zone and/or riser section will descend and settle to the lower portion of the gasifier, filling the vertical section 230 as well as a portion of the horizontal section 220. The horizontal portion 220 is designed so that solids will not reach the vertical portion 215. This design safely protects the metal pipe connected at inlet 210 from hot settled solids, which may range in temperature up to 2000 ° f. Further, a length to diameter ratio of at least four of the horizontal portion 220 may be employed such that settled solids may be blown back into the gasifier upon resumption of the gasification operation. Operational and safety concerns are greatly reduced due to the reduction and/or elimination of plugging of the main gasification agent supply lines.

The gasification agent flowing through the inlet portion 225 enters the conical portion 240 of the LMZ 200. The superficial gas velocity at the throat in the inlet 225 may be between about 50ft/s and 300 ft/s. The wide range of velocities that can be used to introduce the gasification agent into the gasifier increases operational flexibility by providing a method of introducing and distributing the gasification agent from start-up to full load. The gasification agent may be mixed with the solids that flow back and fall into the bottom of the LMZ 200. The coke carbon (char) in the refluxing solids is burned by the oxidant in the gasifying agent. An indication as to whether the solids are being well refluxed and mixed, especially always towards the positive bottom of the conical section, can be inferred from a set of temperature indications 280 while operating the apparatus. If a sufficient amount of solids has flowed back into the lower bottom portion of the LMZ, the temperature indication 280 will be nearly the same as the other temperature indications inside the gasifier. If less hot solids are flowing back into the bottom of the LMZ than desired, the solids level in the riser can be increased by reducing the rate of ash discharge or by adding more inert solids to the gasifier. This increases the rate of solids flow recycled from the riser into the mixing zone, increasing the density of solids in the LMZ200, which increases the rate of hot solids returning through the LMZ 200.

The gasification agent flows into the cylindrical portion 250 of the LMZ200 and the remaining oxygen in the gasification agent will be consumed by the coke carbon in the circulating solids. In a properly operated gasifier, the set of temperature indications 285 and 290 will be nearly identical to the set of temperature indications 280. The gas stream entering the LMZ200 and the gases produced by the combustion and gasification reactions exit the LMZ at outlet 260. The superficial gas velocity exiting the LMZ at outlet 260 may be in the range of about 5ft/s to 15ft/s, which is sufficient for the gas to entrain a substantial amount of solids out of the LMZ. This allows the return flow of fresh recycle solids from the riser to traverse the LMZ. The temperature profile in the LMZ is maintained during the combustion and gasification reactions as coke is continuously introduced into the LMZ and fresh solids are refluxed down. The bed density in the LMZ may be between 15-40 pounds per cubic foot. Such bed density in the LMZ can be obtained by adjusting the solids level and aeration rate in the riser (affecting the rate of solids from the riser to the mixing zone) and by adjusting the distribution of gas between the LMZ and the upper mixing zone 300 (affecting the superficial gas velocity in the LMZ).

The gas injected into the LMZ flows upward to the Upper Mixing Zone (UMZ) 300 as shown in figure 3. Unreacted oxygen in the feed gas from the LMZ may first encounter coke carbon in the upper portion of the LMZ and the lower portion of UMZ. The coke char may be refractory in nature (e.g., non-reactive from a gasification standpoint) and is present in the circulating solids that are recycled from the riser 700 (fig. 1) through the non-mechanical valve 800. In the embodiment shown in fig. 3, the coke carbon can be utilized to generate the thermal energy that may be necessary for the highly endothermic gasification reaction that occurs in riser 400. The gasifier temperature profile is maintained as the heat of combustion produced is dissipated through sensible heat (sensible heat), heat loss, and the endothermic nature of the gasification reaction in the syngas exiting the gasifier. Due to the potentially significantly high solids circulation rate (with high mass flux), the coke carbon content in the circulating solids can be in the range of about 0.1% to 4%, which is greater than an amount sufficient to consume all of the oxygen in the feed gas. Since the recycled solids flowing from the riser into the mixing zone can be in the range of about 1600-. Oxygen from the lower mixing zone can be rapidly consumed upon encountering coke char.

For some applications, additional oxidant may be necessary to consume any excess coke carbon in the recycled solids. This is accomplished by adding the oxidant 1500 directly to UMZ300, as shown in the embodiment in fig. 3. The percentage of coke carbon content in the recycled solids is controlled by the solids recycle rate, the coal feed rate, the total gasifier temperature, and the temperature profile along the height of the gasifier. The distribution of the oxidant in the feed gas is helpful for controlling the heat release along the lower portion of the gasifier loop. High solids circulation rate and uniform and distributed heat release prevent hot spots (hotspots). Hot spots can be highly detrimental to gasifier operation as they can lead to caking, slagging and clinker formation.

The high solids reflux and equally high solids circulation rate facilitate uniformly high operating temperatures around the gasifier circuit 100, resulting in high hot gas efficiency with the desired gaseous products. The hot solids circulating around the gasifier loop can be considered as a thermal flywheel (thermal flywheel) where energy is added by coke combustion and consumed by gasification reactions, heat losses and sensible heat. In one complete cycle around the gasifier loop, about 5% of the thermal energy is added to the thermal flywheel in the mixing zone, which is eventually consumed in the riser and other parts of the gasifier. Because the energy added and consumed is only a small percentage of the thermal energy circulating around the gasifier loop, the gasifier temperature around the loop is nearly uniform.

Coal or other carbonaceous solids from the feeder 1600 may be added UMZ300 in the upper portion, as shown in the feed portion embodiment of the transport gasifier in fig. 3. Depending on the reactivity of the feed solids, the Mass Mean Diameter (MMD) of the feed solids may be in the range of 200 to 500 microns. The MMD of low rank coals, which tend to be highly reactive, can range from 350 microns to 500 microns. Such large feed sizes reduce grinding costs and also produce ash in a size range suitable for maintaining high solids (ash) circulation rates in the transport gasifier loop.

Since all of the oxygen fed to the gasifier may be consumed by the coke carbon in the circulating solids in the LMZ and in the lower portion of UMZ, the coal fed to the gasifier may not contact any oxygen in the feed gas. For most chemical applications, coal is CO₂Or nitrogen to the gasifier. Since fresh coal is not in contact with oxygen, localized hot spots may be avoided and the possibility of frit formation may be eliminated. For air-blown operation of a gasifier for Integrated Gasification Combined Cycle (IGCC) applications, it may be advantageous to transfer coal using air. The amount of air used for such transfer is less than about 15% of the total air injected into the gasifier in such applications. The high solids circulation rate in the gasifier loop and the different height injection of coal in the upper portion of UMZ300 can be done quicklyOxygen is dispersed in the transfer air and the likelihood of any hot spots forming in the gasifier is minimized.

Due to the high solids circulation rate in embodiments of the transport gasifier, the coal particles are heated at a high rate (e.g., at a rate of about 50,000 ° f/sec) in the lower portion of the riser 400 of the gasifier. Such high heating rates result in a large portion of the feed being produced as volatiles, and many of the thermal cracking of the volatiles and gasification reactions occur in the riser. The carbon conversion in the riser to useful gaseous products may be in the range of 65-80% on the first pass through the riser. Unreacted coke carbon can be collected by the cyclone system and returned to the mixing zone to react with the oxidant fed into the lower portion of the mixing zone. The heat released by the partial or complete oxidation in the mixing zone maintains the gasifier at the desired temperature. The density of the inert solids circulating around the gasifier loop may be in the range of 15 to 20lbs/cu ft in the riser. The mass mean diameter of the solids in the riser in embodiments of the present disclosure may be in the range of 75 microns to 100 microns, such high density of the solids provides a large amount of surface area and is effective for cracking small organic molecules and other volatile removal products (decomposed products) from coal to the desired syngas components of CO and hydrogen.

For highly reactive fuels such as low rank coal, the configuration of the transport gasifier may have the same or similar internal diameter as the LMZ, UMZ and riser. For lower reactivity fuels, the LMZ inner diameter is larger than the upper portion of the gasifier. Because the LMZ will handle more coke carbon from less reactive fuels, the functionality of the LMZ is to optimize the partial oxidation and steam gasification reactions.

Unreacted coke carbon and recycled inert solids travel along riser 400 to the top and exit riser 400 through specially designed elbow 450 connecting riser 400 with tilt transition joint 550. An example of a bend is illustrated in fig. 4. The configuration and design of elbow 450 minimizes pressure drop and avoids corrosion of the tilt transition joint 550 and elbow 450. Solid particles that make up the high quality circulating solids in a transport gasifier can be continuously produced from ash derived from the feed coal in the gasifier. They may have irregular shapes and be abrasive. If the elbow is not carefully designed, even a corrosion resistant refractory will last only a small portion of its intended life. The solids and gas streams enter elbow 450 at a velocity of 15 to 35 ft/s. If technically feasible long radius elbows 450 based on other limitations are used, the circulating solids stream impinges and tends to erode the upper portion of the elbow. If a T-shaped or cross-shaped bend is used, both the upper and lower portions of the bend tend to corrode. In the embodiment of fig. 4 used in one embodiment of a transport gasifier, a small portion of the recycle stream enters the extension of the elbow. This flow circulates around in the extension of the elbow and enters the tilt transition joint 550, pushing the main circulating flow entering the tilt transition joint 550 away from the upper portion of the transition joint 550. These actions result in the primary circulation flow being directed toward the lower portion of the crossover joint 550, and the contact point is referred to as the first bottoming (touch-down). Such contact (e.g., second bottoming, etc.) may occur in an improperly designed system. In one embodiment, the extension of the elbow 450, along with the tilt adapter 550, is designed to reduce or eliminate the effects of erosion and bottoming of the upper portion of the adapter 550 refractory.

The solids and gas mixture exiting riser 400 through elbow 450 enters the first stage cyclone, namely pre-salinator cyclone 500. As shown in fig. 4, the transition joint 550 connecting the riser elbow 450 and the pre-salination cyclone 550 is downwardly sloped. The angle of inclination < a > may be in the range of about 15 degrees to 60 degrees, depending on the characteristics of the solids circulating in the gasifier circuit. The inclination will cause the solids to separate from the gas in the crossover 550 and the mass of salt-out solids (salting-out) will flow along the bottom of the crossover and directly into the barrel of the pre-salinator cyclone 500 without much rotation along the wall; this behavior of solids, together with other concepts described in patent 7,771,585, can reduce the potential for corrosion of the cyclone walls, 7,771,585 is incorporated herein by reference in its entirety. The purpose of the preplating cyclone was conceived for high solids circulation rates and mass flux critical to the performance of the circulating pressurized fluidized bed gasifier. The presaltor cyclone of fig. 4 can be implemented without a vortex finder and without a ceiling. These concepts reduce or eliminate many of the reliability problems encountered in industrial high pressure, high temperature cyclone designs, operation and long term operation.

The solids collected by the pre-salination cyclone 500 may then flow into a seal pipe 900 as shown in fig. 5, fig. 5 showing a sub-circuit for a cyclone system including a pre-salination cyclone, seal pipe 900 and a crossover joint between the pre-salination cyclone 500 and riser cyclone 600. The seal pipe includes a downcomer (downer) 910 connecting the cone of the pre-salinator cyclone to a horizontal leg section 930 on one end, a vertical seal pipe riser section 920, and an inclined section 940 connecting the seal pipe riser and gasifier riser 710. The length of the horizontal leg portion 930 may be about 2-10 times the inner diameter of the horizontal leg and depends on the solids circulation rate and characteristics in the gasifier loop. Solids leave the horizontal leg through a short vertical leg (charge lock riser 920) and flow upward; the height of the seal tube lifter will depend on the design of the other parts in the seal tube loop. In one embodiment of a transport gasifier, the height of the seal pipe riser 920 will be such that the solids level in the seal pipe downcomer 910 can be less than about 4-10 times the downcomer diameter. In certain embodiments, the pressure differential between the pre-salinator cyclone inlet 510 and the riser cyclone inlet 590 may be about the same as the pressure differential between 510 and the dip tube outlet 990 to the riser. The additional flow resistance (flow resistance) in the lock-off downcomer is reflected in the form of the solids level 915 in the downcomer. The higher the flow resistance, the higher the solids level in the downcomer. The design of the height of the seal tube riser can be used to adjust the flow resistance in the seal tube and the solids level in the downcomer.

One purpose of the charge seal pipe 900 may be to substantially ensure that the process gas flows upward from the pre-salinator cyclone to the riser cyclone inlet. This is achieved using a flow column of solids in the charge lock tube which prevents short circuiting of the process gas flow to the riser. Normally, the flow of solids through the lock tube is driven by the column of solids in the downcomer. In embodiments of the present disclosure, the solids stream is driven by both the pressure differential between the pre-salinator cyclone and the riser and the column of solids in the downcomer. Due to this pressure difference and/or the column of solids, a higher solids flux can be achieved by a material lock pipe with a minimum solids level in the downcomer and with minimum requirements for aeration of the solids. For recycle solids loops that require high solids recycle rates, such as in the case of gasification, embodiments of the present disclosure result in a compact seal tube design that is feasible for large-scale industrial gasifiers. In addition, the solids level 915 in the downcomer may also be adjusted by the resistance of the flow path from 510 through the crossover joint elbow 520 to the riser cyclone inlet 590. It may be desirable to increase the flow resistance in this part of the circuit so that the solids level in the seal leg downcomer can be further minimized to reduce the aeration rate and maximize the solids flux in the seal leg.

To ensure a high solids circulation rate in the gasifier circuit, it may be desirable for the solids to flow smoothly through the charge seal pipe. This can be achieved by injecting a minimum amount of recycle gas into the charge seal. The recycle gas characteristics may be nearly identical to the syngas produced in the gasifier, but the recycle gas has been subjected to cooling, purification, and recompression. In this embodiment, the aeration gas 980 toward the lock pipe is divided into three sub-streams. The aeration flow towards the lock downcomer 910 is generally downward sloping and the superficial velocity (superficial velocity) is between 0.03 and 0.1ft/s in the cross sectional area of the lock downcomer.

The aeration gas 950 toward the horizontal portion 930 may be implemented by a nozzle 1100 having a design as shown in fig. 6. This part of the transport gasifier comprises two branches and is called dog-leg nozzle (dog-leg nozzle). Gas supply manifold 1120 forms a substantially right angle with exhaust/purge manifold 1130. This type of aeration nozzle embodiment can be used with refractory-lined pipes, which can have a length to diameter (L/D) ratio of typically greater than 20 if straight nozzles of the prior art are used. Such high L/D ratios result in nozzle plugging which is detrimental to operation. As shown in fig. 6, the tubes typically have two layers of refractory material due to the typical high pressure, high temperature and corrosive environment of a circulating fluidized bed gasifier. The inner layer 1140 is in contact with the circulating solids through the flow channels 1110 and comprises a corrosion resistant refractory material. Outer layer 1150 is in contact with shell 1160 of the tube and comprises insulating refractory to ensure that the shell metal temperature is below 300 ° f. The distance between the inner channel wall 1115 and the point of interconnection between the purge leg 1130 and the gas supply leg 1120 may be in the range of about 4-8 times the inner diameter of the nozzle. Because of the L/D ratio of the present embodiment, the aeration gas from gas supply manifold 1120 can push solids out of the nozzles and into the flow channels even if the nozzles are filled with solids. This embodiment is successfully used in transport gasifier nozzles where the aeration gas and gasification agent flow direction are upward.

Keeping the nozzles clean after shutdown or shutdown can help ensure that the aeration gas flows to fluidize the solids and maintain a high solids flow through the charge seal pipe. The rate of aeration to the horizontal leg of the seal pipe may be between about 0.03-0.1ft/s based on the cross-sectional area of the horizontal leg and the gasifier operating pressure and temperature. Another substream of the aeration gas 950 is fed to the lock riser. Under normal circumstances, aeration to the lock riser is not necessary. The only case where aeration gas may be required at one time is when the solids flux is above about 450lb/ft²s is. The normal capacity of the charge seal pipe proposed in the present invention of the transport gasifier for the solids stream driven by both differential pressure and the downcomer solids column is about200-500lb/ft²s is in the range of.

The gas with greatly reduced particulate loading exits from the top of the pre-salinator cyclone 500 and enters another cyclone at the top of the riser 700. FIG. 7 gives a schematic representation of a riser cyclone 600 of a transport gasifier. In this non-limiting embodiment, the riser cyclone 600 does not have a cone and has the same diameter as the riser, which simplifies the design and construction. It simply has a tangential inlet to the riser. Since the riser cyclone 600 inlet receives a low concentration of fine particles in the gas stream, the cyclone has a vortex finder to ensure high capture efficiency.

Prior art designs supporting vortex finders are inadequate in the high pressure (up to about 1000 psig) and high temperature (up to about 2000 ° f) environments of transport gasifiers. As shown in fig. 7, embodiments of the present disclosure operate satisfactorily in this gasification environment. The vortex finder tube has a thin layer of refractory material on both the inside and outside to protect against corrosion. The holder for the vortex finder is embedded inside an insulating refractory that is attached to the shell with an expansion ring (expansion loop). The relatively low temperatures at the location of the support and the expansion loop ensure that the support is subjected to minimal additional stress caused by thermal expansion.

The collection efficiency of the two cyclones in combination can exceed 99.999%. Such high collection efficiency facilitates high carbon conversion in the gasifier, as loss of coke carbon through the cyclone system is minimized. The pre-salinator cyclone concept presented in U.S. patent No. 7,771,585, in conjunction with embodiments of the present disclosure, helps achieve high collection efficiency in harsh gasification environments while protecting the cyclone refractory from corrosion and reducing the catastrophic failure inherent in using prior art cyclones.

Certain applications, such as power generation, among others, may require precise control of the desired steam generation rate from cooling the hot syngas from the gasifier and ensure that the design power output is maintained. However, there are many design uncertainties and equipment aging that can cause the actual steam generation rate to vary from the design rate. One of the desirable features, and one that is also effectively a viable approach, is to adjust the gasifier outlet temperature to achieve precise control over the rate of steam generation. The extent to which the operating temperature of the entire gasifier circuit can be varied and the rate of change to achieve and maintain the desired gasifier outlet temperature are limited. As shown in fig. 8, the transport gasifier outlet temperature can be easily adjusted by injecting a small portion of the oxidant 1500 into the pre-salinator cyclone 500 or riser cyclone 600 outlet where the solids concentration is low and the carbon concentration in the solids is relatively high. The portion of oxidant 1500 injected is less than about 5% of the total oxidant entering the gasifier. In this embodiment of the transport gasifier, oxidant injection also slightly improves carbon conversion in the gasifier loop and reduces any aromatic content in the syngas.

The propensity (dependence) for solids circulation in the gasifier circuit depends on the static head of the solids in the riser. The solids in the riser may need to be in a fluidized state. This is achieved both by the gas entrained by the solids flowing down in the riser and by the fluidization with the recycle gas through the nozzles and distributor in the riser. In coal processing, the circulating solids are ash from the coal itself, and the mass mean diameter of the solids can range from about 75 microns to 100 microns, depending on the ash characteristics and cyclone efficiency. Solids in this size range naturally entrain a certain amount of gas as they flow from the presaltor cyclone to the riser through the charge lock pipe. In addition, nozzles advantageously positioned around the risers and aeration grid at the bottom of the large diameter risers as shown in the embodiment of fig. 9 provide sufficient fluidization and hydrostatic head to maintain a high solids circulation rate around the gasifier circuit. Aeration gas 1700 flows through a distribution grid typically located about six to eighteen inches below non-mechanical valve 800. The solids level in the riser is maintained substantially constant by removing coarser ash from the bottom of the seal pipe riser and finer ash downstream of the transport gasifier.

A non-mechanical valve 800 connects the riser to the mixing zone as shown in fig. 10. One purpose of the non-mechanical valve is to reduce or prevent the reverse flow of gas from the mixing zone into the riser. Typical non-mechanical valves that have been used in practice are called J-legs, L-legs and Y-legs. For both J-legs and Y-legs, the angle of inclination varies according to the characteristics of the circulating bed of solids. If the coal throughput is low, the gasifier size is small and the centerline distance between the riser and the riser is relatively small. Under these conditions, a J-leg is the preferred configuration. As the centerline distance between the riser and the riser increases, then the riser hydrostatic pressure necessary to overcome the J-branch resistance also increases. This entails an increase in the height of the gasifier and a corresponding increase in the structural height and therefore in the capital costs. For transport gasifiers requiring a large throughput, the new configuration as shown in fig. 10 and referred to as an L + J branch provides potential advantages. The short L portion in the illustrated embodiment will act as a non-mechanical valve that reduces or prevents the reverse flow of gas. The inclined J section will become part of the mixing zone/riser in such a way that the oxidant 1500 and steam mixture can be introduced into the J section and the coke combustion reaction can be initiated. In this way, hydrostatic head losses due to non-mechanical valve drag are significantly reduced, and thus making it possible to reduce the riser height. Furthermore, in the present embodiment, an additional volume (J portion of L + J branch) of the gasifier in which the combustion and gasification reactions proceed similarly to the combustion and gasification reactions in the mixing zone and the riser becomes feasible. This reduces the height of the riser portion of the gasifier. In general, the illustrated L + J embodiment may reduce the height of the gasifier, which may be beneficial for large-scale industrial gasifier designs.

Examples

One non-limiting embodiment of an engineering-scale test unit of the transport gasifier illustrated in FIG. 1 that is constructed and broadly tested is described below. Any of the descriptions, ranges, or other information in this example should not be taken as limiting the scope of the disclosure above. The test unit gasifier had a nominal coal feed rate of between 3,000 to 6,000lbs/hr and used both air and oxygen as oxidants to react with the coke carbon in the circulating solids to provide heat for the gasification reaction. Various embodiments of the transport gasifier were first tested in a cryogenic flow test unit with a similar configuration before being tested in an engineering scale unit using coal. Many different low rank coals were tested. The startup solids inventory includes coarse ash discharged from the gasifier from previous test runs. The material in the solids stream at the test facility sometimes included sand having an average particle size of 100-120 microns. Over a period of two days, the sand was gradually replaced with ash produced from the feed coal. The particle size of the coal ash is slightly dependent on the coal properties and is almost independent of the feed particle size within the range tested. Table I shows typical particle sizes of recycled solids for two different feeds. The median mass diameter was about 100 microns for the sub-bituminous coal tested on the transport gasifier and 80 microns for the lignite tested. Since the data was collected by operating the gasifier at different test conditions, the solids flux in the riser was between 75-350lb/ft²s can vary within a range. Bulk density in the riser from 5 to 15lb/ft³In variation, this is much higher than other circulating fluidized bed risers. Because of the high bulk density in the riser, the temperature is nearly uniform throughout the entire riser. The measured superficial gas velocity in the riser is in the range of 20-35ft/s at an operating pressure in the range of 160-250 psig.

TABLE I

Particle size in recycled solids

The streams leaving the presaltor and riser cyclone were isokinetically (isokinetically) sampled. The results from these samples were used together with the circulation rate to calculate the individual cyclones and overall collection efficiency. The pre-salinator cyclone efficiency is typically greater than 99.5% for testing different fuels at various process conditions. In most cases, the cyclone efficiency is between 99.6 and 99.7%. Due to the high solids loading and relatively large particles at the inlet of the presaltor cyclone, corrosion of the presaltor cyclone walls has been a major concern. The cyclone walls showed little signs of corrosion after more than 6300 hours of operation. This is not the case for conventional cyclones in similar installations which are subject to severe corrosion.

The total collection efficiency achieved during the various tests was about 99.95%. The gas stream exiting the gasifier is typically in the range of 1600-1800F and is cooled to 600-1000F in the syngas cooler. The cooled gas stream was filtered using a candle filter to remove fine dust from the syngas. Typical average particle sizes of fine dust (fly ash) are between 10 and 15 microns. Almost all of the coke carbon loss from the gasifier is associated with the fly ash in the gas stream exiting the riser cyclone. For lignite and subbituminous coals, the carbon conversion in the gasifier is typically greater than 98%. Solids collected by the presaltor cyclone flow into a blanking pipe downcomer; solids flux in the seal tube downcomer is between 100 and 470lb/ft²s, depending on the solids circulation rate tested in the gasifier loop. High solids flux rates are achieved because the solids are fully aerated and near the minimum fluidization void fraction (fluidization void fraction)And because of the favorable pressure differential across the charge seal tube. The void fraction and solids velocity in the seal pipe downcomer and riser have been determined by different measurement methods, including injection of solid particle tracer (tracer) and CAT scanning of the flow stream. Dog-leg aeration nozzles in the lock pipe and elsewhere around the gasifier circuit have been shown to eliminate the need for plugs even in the event of many gasifier shutdowns and shutdowns. The various embodiments of the transport gasifier presented in the figure have been tested on facilities using various fuels under a number of different process test conditions. In addition to testing the present transport gasifier invention for syngas production using various coals, the present concept was successfully tested for about 5,000 hours for a pressurized circulating fluidized bed combustor known as a transport combustor. Testing of two different applications, namely gasification and combustion, has shown that the proposed embodiments of the invention can be used as transport reactors for many other applications requiring large surface area exposure of reactants to solids and high circulation rates.

Claims (20)

1. A transport gasifier circuit comprising:

a lower mixing zone coupled to a lower gas inlet section, the lower mixing zone configured to receive at least one gasification agent through the lower gas inlet section;

an upper mixing zone coupled to the lower mixing zone, the upper mixing zone including an upper gas inlet portion configured to receive a mixture of circulating solids and the at least one gasification agent, the upper mixing zone further coupled to a solids feeder;

a riser coupled to the upmixing zone, the riser configured to receive the mixture of circulating solids, the at least one gasifying agent, and gaseous products from the upmixing zone, the riser further comprising an elbow coupling the riser to an inclined transition joint, wherein the gaseous products result from a reaction between the mixture of circulating solids and the at least one gasifying agent;

a pre-salinator cyclone coupled to the inclined transition joint, the pre-salinator cyclone configured to separate solid particles from the gaseous product;

a seal tube coupled to a lower portion of the pre-salinator cyclone, the seal tube configured to receive solids from the pre-salinator cyclone;

a riser cyclone coupled to an output of the pre-salinator cyclone, the riser cyclone configured to separate finer particles from the gaseous product; and

a riser coupled to the loadlock pipe, the riser cyclone, and the pre-salinator cyclone, the riser configured to receive solid particles from the pre-salinator cyclone and the finer particles from the riser cyclone through the loadlock pipe, the riser further configured to recirculate the mixture of circulating solids to at least one of the downmixing zone and the upmixing zone.

2. The transport gasifier circuit of claim 1, further comprising:

an aeration distribution assembly coupled to the standpipe and configured to facilitate recirculation of a mixture of the circulating solids from the standpipe to a non-mechanical valve, wherein the aeration distribution assembly is located six inches to eighteen inches below the non-mechanical valve.

3. The transport gasifier circuit of claim 1, further comprising:

a non-mechanical valve configured to couple the riser to a lower mixing zone and the upper mixing zone, the non-mechanical valve further configured to reduce a reverse flow of gaseous material into the riser.

4. The transport gasifier circuit of claim 1, further comprising:

an oxidant inlet coupled to an outlet of at least one of the presaltor cyclone and the riser cyclone, the oxidant inlet configured to receive an oxidant.

5. The transport gasifier circuit of claim 1 wherein the lower gas inlet section further comprises:

a spray throat coupled to a U-shaped refractory lined pipe, the U-shaped refractory lined pipe also coupled to an inlet of the lower mixing zone.

6. The transport gasifier circuit according to claim 5, wherein the horizontal portion of the U-shaped refractory lined pipe has a length that is four to eight times an inner diameter of the U-shaped refractory lined pipe.

7. The transport gasifier circuit of claim 1, wherein the lower mixing zone has a diameter at least equal to at least one of the upper mixing zone and the riser.

8. The transport gasifier circuit of claim 1 wherein the upper gas inlet section further comprises:

a plurality of nozzles configured to inject carbonaceous material, the nozzles oriented at a downward angle of fifteen to seventy-five degrees relative to a horizontal reference line.

9. The transport gasifier circuit of claim 1 wherein the upper gas inlet section further comprises:

a plurality of nozzles configured to inject the at least one gasification agent into the upmix zone, wherein a distribution of the at least one gasification agent produces a substantially uniform heat release.

10. The transport gasifier circuit of claim 1 wherein the upper gas inlet section further comprises:

a plurality of nozzles configured to have a gas flow direction upward into the transport gasifier circuit, the nozzles having a downward nozzle connected to a gas source at a first end and an upward nozzle into the transport gasifier circuit forming a T-joint at a second end; wherein a distance between the T-joint and a nozzle outlet into the transport gasifier circuit is four to eight times an inner diameter of the upward nozzle.

11. The transport gasifier circuit of claim 1, wherein the charge seal pipe further comprises:

a charge seal tube riser having a height of twelve inches to thirty-six inches.

12. The transport gasifier circuit of claim 1, wherein the charge seal pipe further comprises:

a downcomer coupled to an output of the pre-salinator cyclone and an input of the blanking pipe, the downcomer configured to receive solids from the pre-salinator cyclone, the downcomer further configured to maintain a minimum solids level.

13. The transport gasifier circuit of claim 1, wherein the riser cyclone further comprises a vortex finder supported by an expansion circuit attached to an outer shell of the riser.

14. The transport gasifier circuit of claim 2 or 3, wherein the non-mechanical valve further comprises:

a short L-leg configured to provide a solid seal against the counter flow of gas, and a long J-leg.

15. A method of using a transport gasifier circuit, the transport gasifier circuit comprising: a lower mixing zone coupled to a lower gas inlet section, the lower mixing zone configured to receive at least one gasification agent through the lower gas inlet section; an upper mixing zone coupled to the lower mixing zone, the upper mixing zone including an upper gas inlet portion configured to receive a mixture of circulating solids and the at least one gasification agent, the upper mixing zone further coupled to a solids feeder; a riser coupled to the upmixing zone, the riser configured to receive the mixture of circulating solids, the at least one gasifying agent, and gaseous products from the upmixing zone, the riser further comprising an elbow coupling the riser to an inclined transition joint, wherein the gaseous products result from a reaction between the mixture of circulating solids and the at least one gasifying agent; a pre-salinator cyclone coupled to the inclined transition joint, the pre-salinator cyclone configured to separate solid particles from the gaseous product; a seal tube coupled to a lower portion of the pre-salinator cyclone, the seal tube configured to receive solids from the pre-salinator cyclone; a riser cyclone coupled to an output of the pre-salinator cyclone, the riser cyclone configured to separate finer particles from the gaseous product; and a riser coupled to the loadlock pipe, the riser cyclone, and the pre-salinator cyclone, the riser configured to receive solid particles from the pre-salinator cyclone and the finer particles from the riser cyclone through the loadlock pipe, the riser further configured to recirculate the mixture of circulating solids to at least one of the downmixing zone and the upmixing zone, the method comprising:

controlling solids level and flow rate into the riser by controlling particle size of solids input through the solids feeder and discharge of coarse ash from the transport gasifier circuit.

16. The method of claim 15, further comprising the step of: maintaining a substantially uniform temperature in the transport gasifier loop by circulating the solids.

17. The method of claim 16, wherein the solids are circulated at a rate of one hundred to four hundred pounds per square foot per second.

18. The method of claim 15, further comprising the step of: the at least one gasification agent is uniformly distributed between the upper mixing zone and the lower mixing zone.

19. The method of claim 15, further comprising the step of: the at least one gasification agent is supplied to the downmixing zone via a jet distributor at a throat velocity of fifty to three hundred ft/s.

20. The method of claim 15, further comprising the step of: adjusting a gasifier outlet temperature by injecting an oxidant at an outlet of at least one of the pre-salinator cyclone and the riser cyclone.