SE451727B - PROCEDURE FOR THE MANUFACTURE OF SIGNIFICANT PARTICLE-FREE SYNTHESIC GAS - Google Patents

Description

451 727 Usually again, it is desirable to remove these solid particles from the product gas. If e.g. the sensible heat in the gas must be indirect heat exchange, it is sufficient to remove the solid particles from the gas, before it is introduced into a exchangers to prevent their accumulation on the walls or the transfer surfaces in the heat exchangers with accompanying disturbance of the liquid flow thereby and the transfer of heat. A method to To accomplish this is to allow the hot particles to strike the surface of water in a quench zone to quench and wet them, whereby they are removed from the gas stream and transferred to the water.

If the product gas is intended to be used for the production of hydrogen gas, by another method the gas is usually quenched by it introduced into water below its surface in a quench zone, whereby they the solid particles are retained in the water, after which it essentially the particulate gas, saturated with water, is subjected to catalytic alternating conversion. A combination of such methods is described in U.S. Pat. No. 3,998,609, which is incorporated herein by reference. In order to prevent accumulation of solids and / or pollutants in the freezing water, is periodically or continuously removed part of the quench cooling water and to maintain a constant liquid level in the quench zone it is replaced with water, preferably water, which is led in a cycle from a sedimentation zone, to which the removed part is delivered.

When the carburettor is allowed to operate at elevated pressure, the fixed the ticks are removed from the system without weakening the pressure and this can be done by inserting the particles into a lock pocket and then released from the system, When the function of the lock pocket is regulated with using valves, the inlet in the lock pocket usually has a relative small diameter compared to the gas-forming apparatus, which means bears that there is a section with downward descending cross-sectional area immediately above the lock pocket.

'Unfortunately, there are cases when the material balance shows that for the amount of raw material for the carburettor and the amount of gas generated a deficiency in the amount of solid particles which are removed via the sluice can. When this relationship survives for a long time, it becomes necessary to shut down the operation and remove the blockage, which usually takes place in the narrower part of the apparatus above the re slussfickventilen. 451 727 An advantage of the present invention is that it makes it possible to produce a substantially particulate gas, consisting of carbon monoxide and hydrogen. Another advantage is that the invention does possible to produce synthesis gas under overpressure. Yet another advantage is that the invention makes it possible to increase the removal of ash and unconverted solid fuel particles from a system for gasification of fuels containing ash.

According to the invention, instructions are given for a process for producing substantially free particle synthesis in an apparatus, including a quench zone, a water-filled collection zone, separated from and below the quench zone, and a valve-controlled passage between the quench and collection zones, leaving one ash-containing fuels undergo partial oxidation under overpressure to generate a stream of synthesis gas, including carbon monoxide and hydrogen and containing hot particles of ash and not converted fuel, cools the hot particles by bringing them in contact with water in the quench zone and, when the valve is open, allows the quenched particles to sink through the quench zone down into the water-filled collection zone below the quench zone, which is characterized by maintaining a continuous flow of water, containing quenched particles from the quenched to the collection zone at a speed to prevent upward flow through said passage of water excluding crowded by the sinking quenched particles.

The raw material for the process according to the invention comprises which ash containing any carbonaceous fuel, e.g. coal, substitute at least coal, lignite, certain types of coke, biomass and the like the material. Usually such fuel is solid, although fuels, which are liquid at elevated temperatures, such as coal- liquid transfer residue, can also be used. To be considered as ash-containing, the fuel must have an ash content of at least about 1 weight-%. If the raw material is melted at elevated temperature, it can be preheated and introduced into the gas formation zone in the form of a liquid.

However, if the fuel is solid even at elevated temperatures, then it must be ground to a particle size of less than 6.35 mm and preferably ground so that at least 95% passes through a 14 mesh sight according to American standard (1.41 mm aperture). The fuel is sprayed 451 727 is then taken into the gas generation zone, where it undergoes partial oxidation dation with a gas, such as air, oxygen-enriched air or essential pure acid, ie acid with a purity of at least about 95%. The phase take the fuel can be introduced into the partial oxidation zone in the mold of a slurry in a liquid, e.g. water or oil or in e in the form of a suspension in a gaseous or vaporous medium, like for example. steam, carbon dioxide or mixtures thereof. Water or : y steam can also be introduced into the gas formation zone or the partial one the oxidation zone as a temperature-modifying component, when the fuel The clay product is liquid or consists of a slurry of .take substances in oil or any other flammable liquid.

In the gas generation zone, the fuel is subjected to partial oxidation at an autogenously maintained temperature between about 980 and 1760 ° C, approximately between about 1090 and 1540 ° C. The pressure in the gas generation zone can vary between about 0.27 and 20.6 MPa, preferably between about 0.41 and 17.1 MPa. The oxygen can be introduced into the gas formation zone at one atomic oxygen content of between about 0.7 and 1.6, preferably between 0.8 and 1.2. If the fuel is solid and is introduced into the gas-forming zone in the form of a slurry in water, the slurry shall be contain less than about 50% by weight of water, when a water content above that amount will affect the thermal efficiency of the reaction.

In a method for extracting heat from synthesis gas, which is prepared by the partial oxidation of an ash-containing fuel, the gas can be passed downwards from the gas generator through a jet cooling zone together with the entrapped particles of ash and any constituent, unconverted fuel particles. The gas is led then off from its original path through the radiation cooling zone and in a preferred embodiment in a more or less upward direction direction to a convection cooling zone, where it is directed upwards in direct heat exchange with a cooling medium, such as water. The fast the particles continue on their way and come into contact with water in a quench zone at the lower part of the radiant cooling zone where they are wetted and tend to settle in the water. The phase take the particles then pass downward through the upper valve in a lock pocket, which can also be considered as a sales zone, there they are collected. Because the upper valve in the lock pocket mostly kept in an open position, the lock pocket is filled with water. In order to empty the solid particles, periodically close the upper valve il 451 727 in the lock pocket and a valve located at the lower part of the the lock pocket is opened, which allows the water and the take the particles removed from the system. where this step has been completed. the lower valve in the lock pocket is closed, the lock pocket is filled water, is pressurized and then the upper valve is opened to allow additional ash or slag to settle and collected in the lock pocket. Alternatively and preferably as a corrosive preventive measure, keep the lock pocket full of water, dan. the. npesamlêde fi ssta. äm fl e flfl ... fömme fi..fl. tf .This åfßtsdkvmmes .Befëvm. that water is introduced preferably at the upper part of the sluice pocket, while the upper valve between the lock pocket and the overcooler the chamber is closed, through a separate inlet with the same as the contents of the lock pocket are emptied through the opened lower valve. In this way, the lock pocket is always full water and air are not allowed to enter the lock pocket.

To prevent the formation of a blockage outside the upper the valve in the lock pocket gets in an embodiment of the invention water circulates externally from the lock pocket to the quench the zone for inducing a downward flow of water containing trapped particles through the upper valve in the lock pocket.

This can be accomplished by withdrawing water from the top len of the lock pocket or in the vicinity thereof and lead it back directly or indirectly to the quench zone. Through a modified ring of valves and pipeline can the opening, which was used for the extraction of water for return to the quench zone, be the same opening used for the introduction of water below the emptying torque of the lock pocket. The outlet line for the outlet the water is suitably separated from the downward stream of water containing quenched particles by means of a shielding plate, so that a minimum of particles are returned to the quench zone. By working in this way one passes continuous flow of water downwards from the quench zone to the collection zone and thereby helps to transfer the solid the material from the quench zone to the collection zone or the lock pocket and thereby prevents the formation of a blockage.

However, this current is interrupted when the lock pocket program for removal of the collected solid particles is initiated. the flow rate of the water from the quench zone to the collection r451 727 the lock zone or lock pocket is not critical but should be larger than the velocity of the upward flow, i.e. the velocity of the upward flow of water which is replaced by the sinking ones the ash particles if there was no circulation. Of practical For this reason, the speed of the downward current should be at least 0.009 m per second, preferably at least 0.015 m per second.

Since the inlet and outlet in the lock pocket are checked with the connection between the outlet of the freezing zone and the the race to the lock pocket a section with gradually decreasing transverse - "", 'h cut area. To prevent larger particles of ash or slag to clog this area or clog the valve, it is advisable to have a atomizer above the tapered section.

After the synthesis gas has left the convection part, it may come to rest. suitable use at any time, e.g. for the synthesis of organic compounds, the production of hydrogen or for use as a fuel.

Although the radiation cooler has been described as a downwardly directed device, flow and the convection cooler as a device with upward directional herring, modifications to the equipment are possible, so that it has the gas flow in either direction through each piece of the equipment.

In another method of heat recovery, the oxygen content is introduced. the gas and fuel in the gas generator or the partial oxidation zone at its upper part and may then pass downwards through the gas generator. A quench zone containing water is located at the lower part of the gas generator, but before the hot product the gas reaches the quench zone, it is led off in a more or less upward direction into a radiation cooling zone, at the same time as the the solid particles continue on their way into the freezing water net, where they are wetted and sink through the water in the quench zone down in a lock pocket or collection zone. The derived gas can then in one case led upwards through a radiation cooling zone and down through a convection zone or in another case down through a radiation cooling zone and upwards through a convection cooling zone or alternatively either upwards or downwards through both cooling zones. 451 727 To facilitate the movement of solid particles from the quench the collection zone to the collection zone, water is also allowed here cool from the collection zone to the quench zone, so that a constant downward flow is produced from the quench the zone through the upper valve in the lock pocket of the collection zone.

Water, which may circulate externally from the collection zone, may be carried in the quench zone above the water contained therein Yta t °° dh .S-Prutf-sa På yäênf vihlkeël fl sdiörnaitv alla sYefêëPella flïf particles are wetted and thereby sink or on the other hand> it can be inserted below the surface of the freezing water and led upwards against the surface to increase the turbulence in the quench zone or conduction downwards to thereby increase the pressure of the water flow to the sluice pocket and reduce the tendency of slag or ash particles to form a bridge across the narrower part of the inlet in the lock pocket with the resulting blockage of flow of solids substances into the lock fioca or any combination of the three. When it the circulating water is introduced below the surface of the quench water in an ascending direction, a flotation effect is produced, which tend to separate carbon-rich particles from the denser particles. which are ash-rich, with the quench "blowing" a "is taken from near the surface of the freezing water to remove water with a higher proportion of carbon-rich particles. Freeze cooling the blowing current is a flow taken out of the quench zone to help reduce the amount of pollutants, such as rides and formats-in the freezing water. Water is fed into the the cooling zone to replace what was taken out in connection with the quench "blow-down" to thereby maintain the water the level in the quench zone is substantially constant.

In another embodiment of the invention, water, rather than allowing water to circulate from the lock pocket to the freezer chamber, is taken out of the lock pocket and combined with the cooling blow-off stream and transferred to a sediment where the solid particles are deposited from the water, which can then be led back to the quench zone which cooling water for refilling or used for the preparation of additional slurry raw material. To compensate for the increase the flow of water to the sedimentation device increases the flow of quench cooling water for refilling in the quench zone 451 727 a in an amount equal to the amount taken from the sluice the pocket. In this way, a flow of water from the overflow is maintained. the cooling chamber through the upper valve in the sluice pocket into the sluice the pocket.

Examples of the effectiveness of the application of the present invention finning is evident from a series of high-pressure carbonation runs, in which the raw material introduced into the carburettor consisted of a carbon with the designation Kentucky no. 9. All runs were made during_ essentially identical operating conditions. The first run was for 26.6 hours, when operations had to be stopped due to slag covered the upper valve in the lock pocket. After removal of the cover resumed the gasification but cover with slag resulted in the second run being shut down after 18 hours.

The third run lasted for 20.5 hours and the fourth for almost hours, when both had to be switched off for the above reasons.

Before the fifth run, a blow-off system was installed for to at constant speed lift water-from the upper part of the lock pocket into the quench "blow-down". The downward the flow of water from the quench chamber via the upper valve len in the lock pocket and into it at a speed of 0.021 m per second was successful as far as the fifth run continued for 42.5 hours and did not end due to clogging with slag but for mechanical reasons. When this relationship rigged, the unit was commissioned and operated successfully for 66.8 hours. mar without interruption, when the trial-voluntnn;; ended. Then the unit was operated for 112 consecutive hours.

From previous experiments it appears that before the application of According to the present invention, it was necessary to interrupt the operation of the unit after about 20 to 25 hours of operation due to clogging. But after the installation of a system, with the help of which water could led from the quench chamber via the upper valve in the sluice pocket and into it, there was no clogging or covering with slag in the equipment and over 200 hours of operation was completed without this problem occurring.

Although the invention has been described in connection with gasification system, where the synthesis gas is introduced into the quenching water under the surface, so that not only the solid particles of ash and not .cl 4ö1 727 ' 9. _ converted fuel is quenched but also the synthesis gas as such, it works equally well in gasification operations, in which water in the freezing zone is present in a more or less inert condition. Various modifications of the invention as described herein, can be done without deviating from its spirit and d within the same framework and therefore only restrictions should be made which are set out in the appended claims.

Claims (12)

451,727 Claim 1; Process for producing substantially particle-free synthesis gas in an apparatus. including a quench zone. a water-filled collection zone. separate from and below the quench zone. and a valve-regulated passage between the quenching and scalding zones. wherein the ash-containing fuel undergoes partial oxidation under overpressure to generate a stream of liquefied gas. comprising carbon monoxide and hydrogen and containing hot particles of ash and unconverted fuel. cools the hot particles by contacting it with water in the quench zone and. when the valve is open. liters of the quenched particles sink through the quench zone into the water-filled sedimentation zone below the quench zone. characterized in that a continuous flow of water containing quenched particles is maintained from the quench zone to the collection zone at a speed to prevent an upward flow through said passage of water displaced by the descending quenched particles. . S7 2. Method according to Claim 1, characterized in that the flow is maintained by allowing water to circulate from the collection zone to the quench zone. i3. method according to claim 2, characterized in that the circulating water is introduced into the quenching zone above the surface of the water volume contained therein. 4. A method according to claim 2, characterized in that the circulating water is introduced into the quench zone below the surface of the water volume contained therein. Method according to one or more of claims 1-4. feel the gases and the entrapped particles. son leaves the partial oxidation zone. passes through a radiation cooling zone. before the particles reach the quench zone. 1 \ 451 727 Method according to one or more of claims 1-4. FEELS that the gases are diverted to a radiation cooling zone. while the particles continue on their way into the water in the quench zone. 7. A method according to claim 5 or 6. characterized in that the path of the gas through the radiation cooling zone is downward. B. Method according to Claim 5 or 6, characterized in that the path of the gas through the radiation cooling zone is upwards. Method according to one or more of claims 1-8. feel that the collection zone is being filled with water. while the particles are taken out of it. 10. A method according to claim 1. characterized by water. taken from the collection zone. combined with a blowing current. taken from the quench zone. that the mixture thus formed is allowed to settle and that water. extracted from the collection zone. led back to the system. ll. Method according to claim 10, characterized in that the deposition water is led back to the quench zone. 12. A method according to claim 10. characterized in that the deposition water is introduced into the partial oxidation zone together with the ash-containing fox.