JPS62290794A - Method and apparatus for coal gasification - Google Patents

Abstract

PURPOSE:To enable the production of a large volume of a raw gas for coal gasification with a small apparatus, by reducing the air pressure after formation of a high-concn. nitrogen gas through the use of an adsorbent capable of adsorbing a large amt. of oxygen and pressurized air, thereby forming oxygen- enriched air, and utilizing the air for coal gasification. CONSTITUTION:Air which has been pressurized to such an extent that coal can be transported and the coal packing vessel can be sufficiently pressurized is passed through a plurality of columns packed with an adsorbent in which the equilibrium adsorption amt. of oxygen is larger than that of nitrogen at the same pressure and the same temp., thereby forming a high concn. nitrogen gas. Before the adsorption of oxygen reaches equilibrium, the pressure of air passing through the column is reduced to such an extent that a gasifying agent is sufficiently fed into a coal gasification oven, thereby desorbing the adsorbed oxygen and forming oxygen-enriched air. The above procedures are repeated in a plurality of columns while staggering the operation time, thereby continuously forming a high-concn. nitrogen gas and oxygen-enriched air. Thus, a high- purity nitrogen gas is used for transporting coal and pressurizing the coal packing vessel, while oxygen-enriched air is used as a coal gasifying agent.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a coal gasification device, and more specifically, the present invention relates to a coal gasification device that produces coal or other hydrocarbons with an air separation device. The present invention relates to a coal gasification method and a gasification apparatus for obtaining a combustible gas by transporting it as a gas and supplying it to a coal gasification furnace together with a gasification agent produced in an air separation device and causing a reaction under high temperature and high pressure.

[Conventional technology]

Coal is a useful energy source with abundant reserves, but because it is solid and contains a large amount of ash, its fields of use are limited compared to oil and natural gas.

However, if this coal is converted into gas or liquid, it can be used in a wide range of fields and become a useful energy source, so coal fluidization technology is being developed in various countries.

Under these circumstances, coal gasification equipment in particular is being researched and developed as an elemental device for coal gasification combined cycle power generation systems, which are attracting attention as a next-generation power generation method.

Coal gasification involves pulverizing coal into fine pieces and feeding them together with an oxidizer to a high-temperature gasifier. Then, the coal reacts in a high-temperature furnace to cause gasification reactions such as partial oxidation. This generates flammable gas whose main components are carbon monoxide and hydrogen.

In a coal gasification combined cycle power generation system, the sensible heat of the high-temperature combustible gas obtained in the coal gasifier is recovered to produce steam and drive a steam turbine, and at the same time, the gasified combustible gas is used to generate gas. It drives the turbine. This system can improve power generation efficiency by several percentage points compared to conventional steam turbines alone. In response to such large-scale demand for power generation involving one coal and gas, coal gasification equipment is also being made larger in capacity and more efficient.

When coal gasification is performed for the purpose of power generation, it can be roughly divided into two gasification methods: oxygen gasification using oxygen as an oxidizing agent and air gasification using air as an oxidizing agent. Table 1 shows the gasification efficiency, oxidant production cost, and power generation cost depending on the gasification method.

Table 1 In oxygen gasification, the efficiency of the gasifier is good because all the oxidizing agent is reacted, but the production cost of oxygen is required, which increases the power generation cost. On the other hand, in air gasification, the efficiency of the gasifier is low because air that does not react as an oxidant is also supplied. However, since the production cost of oxygen is not required, the cost of power generation will be lower. Therefore, instead of the deep cooling method conventionally used for oxygen production, PSA (Pressure
If Swing Adsorption is used, high gasification efficiency can be obtained at a low oxidizer production cost, so it is thought that the power generation cost will be further reduced compared to a system that gasifies coal using only air.

In the case of gasification, oxygen with high purity at the #fi end is not required. This is because the temperature inside the furnace increases if the temperature of the oxygen-enriched air is even slightly higher than that of air. For example, in the case of gasification using a spouted bed, the ash generated from the coal in the furnace can be easily melted, eliminating the need to unnecessarily accelerate the combustion reaction and raise the temperature, increasing gasification efficiency. . In addition, the reaction is promoted because the oxygen partial pressure increases, and efficiency can be improved.

From this point of view, to produce oxygen-enriched air.

An example using PSA can be found in JP-A-51-50298.

[Problem that the invention seeks to solve]

However, there are various problems in producing an oxidizing agent for a coal gasifier using PSA.

First, coal gasifiers require very high purity nitrogen for the purpose of conveying the coal.

This is because if the gas supplied to the coal gasifier contains oxygen, the coal will explode into powder, which is dangerous. In addition, a lock hopper system is generally used to feed powder into a high-pressure furnace, but since this system mixes pressurized gas and dust, if the gas contains oxygen, the coal will explode into dust. This is because it is dangerous.

In the conventional deep cooling method, nitrogen is also produced at the same time as oxygen, so it was sufficient to use the produced nitrogen as a gas for transporting coal. However, in PSA, the gas that is discarded when oxygen is generated has a higher nitrogen concentration than air, but the oxygen concentration is so high that it cannot be used as a conveying gas.As a result, nitrogen for coal conveying is a different gas. Either the nitrogen must be brought in from the plant or a plant must be built for nitrogen production in addition to the oxidizer production, which ultimately affects the overall cost of the plant and increases the power generation cost.

Second, increasing the capacity requires an extremely large device. P
SA has been operated near normal pressure. Therefore, if a large volume of gas is to be processed, the tower becomes very large. Generally, when trying to increase the capacity of a gasifier, the pressure increases, but in PSA.

Even if the pressure is increased, a large amount of gas must be disposed of, resulting in poor efficiency. Therefore, if the oxidizing agent required for conventional gasification furnaces were to be manufactured using a PSA, a site 30 times larger than that of a Gai et al. furnace would be required. For the purpose of increasing the size, an example in which two stages of attachment and detachment are performed can be seen in JP-A-51-80682. However, it is not considered to be large enough to be used in a gasifier.

The present invention was created after considering the fundamental principles of PSA in order to solve these problems.

The present invention is a PLC for coal gasification that can produce raw material gas such as an oxidizing agent used in large-capacity coal gasification with a very small device.
This invention relates to a coal gasification apparatus using SA and a PSA that uses the PSA to significantly improve the efficiency of the entire system.

[Means for solving problems]

The above-mentioned problem is that the pressure must be high enough to transmit coal to multiple towers filled with an adsorbent that has a larger equilibrium adsorption amount of oxygen than nitrogen at the same pressure and temperature, and to pressurize the coal-filled container sufficiently. Highly concentrated nitrogen gas is generated by circulating air, and before the equilibrium adsorption amount of oxygen is reached, the pressure of the air flowing in the column is reduced to a pressure that can sufficiently supply the gasifying agent to the coal gasifier. Oxygen-enriched air is generated by desorbing the oxygen adsorbed by the adsorbent, and by repeating the above operations in multiple layers at different times, high-purity nitrogen gas and oxygen-enriched air are continuously generated. The problem is solved by a coal gasification method that uses high-purity nitrogen gas for conveying the coal and pressurizing the coal-filled container, and using oxygen-enriched air as the coal gasification agent.

[Effect]

According to the method of the present invention, since high-pressure air is used to generate highly concentrated nitrogen gas, a large amount of gas can be produced in a column with a small capacity, and the oxygen adsorbed on the adsorbent can be Since the tower is regenerated by desorption at low pressure and the generated oxygen-enriched air is used as a gasification agent, there is no waste in the system and the overall efficiency can be improved.

〔Example〕

In describing the details of the present invention, first of all, PSA,
This section describes the basic concept of coal gasification equipment.

Figure 2 shows a simple flow of the coal gasifier.

Table 2 summarizes the gases required for the coal gasifier.

Table 2 The ratio of the oxidizing agent for coal gasification to the amount of coal supplied is preferably the ratio that provides the highest cold gas efficiency.

Here, cold gas efficiency refers to the ratio of the calorific value of the generated gas to the calorific value of the supplied coal.1 Coal gasification is:
Generally, it is mainly based on a partial gasification reaction, and is expressed by the following formula.

Since coal is simple, components such as ash are excluded and expressed as hydrocarbons.From the above equation, the calorific value of the generated gas is highest when all the carbon in the coal becomes carbon monoxide. Since this reaction is a one-exothermic reaction, the reaction proceeds without applying heat from the outside. However, when trying to gasify coal with air, even if there is a certain amount of calorific value, it is diluted by the inert gas nitrogen contained in the air, making it impossible to raise the temperature inside the furnace, and the gas There is a disadvantage that the gasification rate is slowed down and the gasification rate is reduced. especially,
When trying to gasify coal in an air bed, a major feature of the air bed is that the ash in the coal is melted and processed, but in order to do this, the temperature inside the furnace must be raised to a temperature higher than the melting temperature of the ash. The amount of heat generated by the partial oxidation reaction in the above equation is insufficient. So generally, 1! & Increasing the elementary quantity and causing a combustion reaction to occur in parallel with the reaction in the above equation.

→nC0z+-HzO However, if the combustion reactions occur simultaneously, the calorific value in the generated gas decreases, and the cold gas efficiency decreases. Therefore, it is possible to increase the temperature by reducing the amount of nitrogen, an inert gas, contained in the air by using oxygen-enriched air. The oxygen content of this oxygen-enriched air, especially in the air flow bed, can be determined by raising the temperature inside the furnace to a temperature higher than the melting temperature of the ash, and the oxygen concentration is about 25%.

From the perspective of spontaneous combustion, the gas for transporting coal must have at least an m element concentration of 5% or less. In addition, it is most preferable that the amount of gas required for transporting coal is 0.1 (nitrogen supply amount/coal supply amount) from the viewpoint of stable coal transport conditions, and the pressure required to transport coal is 0.1. It largely depends on the amount of supply and the amount of carrier gas, and generally several atmospheres are required.

In order to perform coal gasification with high efficiency in this way, we considered supplying the required gas all at once using a small PSA.

In other words, high-purity nitrogen is produced by adsorbing oxygen at a pressure that is the sum of the gasifier pressure and the conveying differential pressure, and is used as a coal conveying gas, and the adsorbed oxygen is desorbed at the gasifier pressure to enrich it with oxygen. It is characterized by generating air and using it as an oxidizing agent for coal gasification.

FIG. 3 shows the flow of PSA. In PSA, a time-determined component gas is adsorbed at high pressure and desorbed at low pressure. Therefore, low-pressure purge gas has a high concentration of the above-mentioned specific components, while gas extracted at high pressure has a low concentration of specific components. Therefore, in order to separate oxygen and nitrogen from the air, zeolite Adsorbents are used to adsorb nitrogen and produce gas with a high concentration of oxygen. but,
Oxygen-enriched air produced in this manner is not preferred for use in coal gasification. Gases obtained by the nitrogen adsorption type, oxygen-enriched air production method are shown in Table 3 □.

Table 3 It can be seen that the gas produced in such a PSA is very poorly suited when compared with the gas required for coal gasification as described above. In particular, the acidity of the product gas is too high to be used as coal conveying gas. Therefore, it is necessary to reintroduce the nitrogen into another PSA to further increase the nitrogen concentration.This method is undesirable because the apparatus becomes complicated. Furthermore, there are no other utilities that require gas with an oxygen concentration of about 10%.

Furthermore, even if another PSA is reintroduced to further increase the nitrogen concentration and used, the production is always at a lower pressure than the gasifier, so it will be necessary to pressurize again, resulting in a large energy loss.

Furthermore, only a small amount of oxygen-enriched air, which is a gasification agent that is originally required in large quantities, is produced, and a large amount of nitrogen-enriched gas, which should be used as a coal carrier gas, is produced in large quantities.

This point is a major reason why the capacity of PSA cannot be increased.

In other words, one way to increase capacity is to increase the pressure, but since a large amount of gas is discarded, the pressurized energy is ultimately wasted, increasing costs and wasting it. A major drawback was that the inside of the tower was not used effectively to retain the waste gas inside.

As mentioned above, the conventional PSA for producing enriched oxygen was extremely unreasonable for coal gasification, but the present invention has a completely opposite idea and is suitable for coal gasification. He invented a highly compatible PSA and devised a highly efficient power generation system using this PSA.

The gas required for coal gasification (Table 2) corresponds to the gas produced in PSA (Table 3) because it is an oxygen-enriched gas, but the gas required for coal gasification is low pressure (gasification furnace). The gas produced by PSA is completely opposite to this, and is produced in small amounts at high pressure.
This point is the main reason why coal gasification is poorly adapted.

Moreover, there is a lot of wasted gas.

This indicates that there is wasted space in the device. This is the reason why PSA cannot be made larger.

Therefore, an attempt was made to stop adsorbing nitrogen and use the absorbed gas as a transport gas for coal gasification and the purge gas as a gasification agent for coal gasification by adsorbing oxygen. An outline of that time is shown in Figure 4.

rd! An agent that selectively adsorbs elements is disclosed in Japanese Patent Application Laid-open No. 58-33.
Seen in issue 979. In addition, even if it does not have selectivity, there are molecules with very different adsorption rates.
arSieving Carbon), which is
Although the equilibrium adsorption amount is approximately the same for wt element and nitrogen, it has a property that the initial adsorption rate is significantly different between oxygen and nitrogen.

Therefore, in the early stage, a large amount of oxygen is adsorbed, and since the amount of nitrogen adsorbed is still small, only oxygen is adsorbed from the gas that has passed through the layer, and the nitrogen concentration increases. Once the desorption operation begins, the effect is almost the same as selectively adsorbing oxygen.

One embodiment of the present invention will be described with reference to FIG.

The entire system is composed of an air separation device, a coal supply device, and a coal gasification furnace.

The air separation device includes a compressor 18° adsorption unit that supplies air 4;
An adsorption/desorption column 11 that can perform desorption, valves 23, 27, and 29 that periodically open and close gas flow between the adsorption/desorption column All and other devices, and further operations equivalent to those of the adsorption/desorption column All. Significant increase in suction and extraction B12. Valve 23, 27.
Consists of 29. The adsorbent is filled with an agent capable of selectively adsorbing w1 element in large quantities or at high speed.

The coal supply device includes a pressurized hopper 1 that stores coal 1 under pressure.
09 Consists of a feeder 143 for bringing the coal 1 to a supply pressure 4132 a feeder 141 for quantifying the coal 1 and a mixer 15 for mixing the coal 1 and the carrier gas. Furthermore, a valve 22゜26.21. for pressurizing the coal 1. W8 controls the amount of carrier gas! l? It is composed of a total of 31 items.

The coal gasification furnace is composed of a gas furnace main body 161 and a coal burner 17.

Next, the operation of this embodiment will be explained. The air 4 is pressurized by the compressor 18 after dust is removed from the air by a filter attached to the inlet of the compressor 18 .

The pressure to be applied is determined by the coal supply hopper 13 and the eductor 15.
The pressure P1 is set to be equal to or higher than the pressure P1 that can supply a sufficient amount of the transport gas to the gas, plus the pressure loss ΔPp required when the gas passes through the adsorption/desorption groups All and 12 filled with the adsorbent. The pressurized air is supplied to the adsorption/desorption groups All, 12 via the valve 29 or 30.

PSA repeatedly adsorbs and desorbs due to pressure changes within the adsorption/desorption groups All, 12, and the pressure within the adsorption/desorption groups A11, 12 is determined by valves 23, 24, 27, 28, 29, 30. Table 4 shows the opening and closing states of each valve depending on the cycle.

Table 4 First, the adsorption/desorption group All will be explained. When the state of cycle 1 is reached, the valve 29 is opened and pressurized air is directly supplied from the compressor 18 to the adsorption/desorption group 11, so that the pressure of the compressor increases to the adsorption/desorption group All. As a result, oxygen is selectively adsorbed by the adsorbent filled inside the adsorption/desorption group All.

That is, adsorption operation is performed in the adsorption/desorption group 11.

Therefore, the gas sent from the adsorption/desorption group All through the valve 23 to the coal supplying and conveying device is supplied with a gas that has a low U steel content, that is, a high nitrogen concentration, and is suitable as a conveying gas that does not cause coal to spontaneously ignite. If the above operations are performed continuously for a certain period of time, the adsorption/desorption group All will no longer be able to selectively adsorb oxygen.8 In this example, the adsorption/desorption group All will selectively adsorb oxygen at a higher rate than nitrogen. is filled with MSC, which is an adsorbent capable of adsorption. Therefore, it does not mean that oxygen cannot be adsorbed simply because the adsorbent reaches its equilibrium adsorption amount.The reason for this will be explained from the basic performance curve of MSC shown in FIG. 5. The horizontal axis shows the elapsed time after starting the adsorption operation, and the vertical axis shows the amount of gas adsorbed per gram of adsorbent. MSC shows that although the equilibrium adsorption amounts of oxygen and nitrogen are almost equal, the initial adsorption rates are significantly different, and the oxygen adsorption rate is initially much faster than the nitrogen adsorption rate. Therefore, around 1 minute, the amount of oxygen adsorption is larger than the amount of nitrogen adsorption, and as a result, oxygen is selectively adsorbed. Furthermore, if the gas continues to flow for more than 1 minute, nitrogen will also be adsorbed, so selectivity will be lost.The time to switch from adsorption operation to desorption operation is determined from 1 or more.

When oxygen can no longer be selectively adsorbed, the process moves to cycle 2, which is a desorption operation for the adsorption/desorption group All. In cycle 2, first, the produced gas switching valve 23 of the adsorption/desorption group All and the valve 29 for supplying air, which is a raw material gas, to the adsorption/desorption group All are simultaneously closed. Then, the purge gas switching valve 27 is opened. When the valve 27 is opened, the burner 17 that supplies the gasification agent to the coal gasification furnace 16 and the adsorption/desorption group All communicate with each other, and the adsorption/desorption group A11 is set to a higher pressure than the coal gasification furnace 16 in advance. Therefore, the gas in the adsorption/desorption group All flows into the coal gasifier 16. Then, the pressure within the adsorption/desorption group A11 begins to decrease. A large amount of oxygen is adsorbed on the adsorbent in the adsorption/desorption tower All by adsorption operation at high pressure. This adsorption/desorption group A
Oxygen adsorbed by the adsorbent in the adsorption/desorption group Δ11 is desorbed by reducing the pressure in the adsorption/desorption group Δ11.

As a result, the oxygen concentration of the gas supplied as a gasification agent to the gasification furnace 16 becomes higher than that of the raw material gas air 4, resulting in so-called oxygen-enriched air.

When the desorption operation is completed, cycle 1 is repeated again, and the same operation as above is performed on the adsorption/desorption group B12.

However, when the adsorption/desorption group All is performing the adsorption operation, the adsorption/desorption group B12 performs the desorption operation, and when the adsorption/desorption group All is performing the desorption operation, the adsorption/desorption group B12 performs the adsorption operation. Coal conveying gas with a high nitrogen concentration and oxygen-enriched air for coal gas and other agents can be obtained almost continuously at the same time.

The coal conveying gas is supplied to the pressurizing hopper 10 via the valve 22, to the supply hopper 13 via the valve 26, and further to the eductor 15 via the valve 31 having a flow rate controller function. The coal is crushed and classified in a furnace 16 to a particle size that is easily gasified, and then supplied to a coal pressurizing hopper 10.

Since the coal 1 is solid, it cannot be directly fed to the pressurized gasifier, so a lock hopper system is used. This principle will be explained next. First, valve 25
is closed, the valve 31 is opened to keep the pressure hopper 10 at normal pressure, and the coal 1 is introduced into the pressure hopper 10. Next, the valve 31 is closed and the valve 22 is opened to supply and pressurize the conveying gas to the pressurizing hopper. When the pressure is equal to that of the supply hopper 13, which has been pressurized in advance, the valve 25
is opened and the coal 1 is supplied to the supply hopper 13 from the pressurized hopper 1o. Thereafter, by closing the valve 25 and opening the valve 21, the transport gas inside the pressure hopper 1o is extracted, the pressure hopper 13 is brought to normal pressure, and the operation moves to the beginning.

Coal 1 filled in supply hopper 13 is metered by rotary feeder 14 and sent to eductor 15 .

The eductor 15 controls the coal 1 and the flow rate adjustment valve 31 controls the flow rate I.
The oxidizing agent and coal are mixed with the aIyi conveying gas and sent to the burner 17 through the Wi pipe.The oxidizing agent and coal are mixed in the burner 17 and sent to the coal gasifier 16.

In the coal gasification furnace 16, the coal 1 reacts with an oxidizing agent in a high-temperature furnace and is gasified to generate flammable gas. Since the oxidizer is oxygen-enriched air, it can raise the temperature inside the furnace higher than normal air, so even if gasification is performed with lower oxygen/coal, the ash content in the coal 1 can be melted. Therefore, gasification efficiency can be improved.

The ratio between the amount of N1-enriched air produced and the amount of carrier gas produced is:
Although it varies greatly depending on the cycle interval, Sv (volume velocity) of the adsorption/desorption group, etc., the operating range depending on the required gas composition can be determined to some extent by calculation.

each at the nitrogen concentration in the carrier gas. FIG. 6 shows the relationship between the amount of gasifying agent produced and the oxygen concentration of the gasifying agent. The horizontal axis shows the oxygen concentration of oxygen-enriched air, which is a gasification agent, and the vertical axis shows the ratio of the amount of gas and other agents produced to the raw material (air). In the figure, the carrier gas nitrogen concentration is 99.9, 99, 95.90%.
The relationship between the two is shown when .

Generally, the carrier gas nitrogen concentration can be increased by shortening the adsorption time and switching between adsorption and desorption at a faster time, and by increasing the difference in operating pressure during adsorption and desorption. Gas nitrogen concentration can be increased.

When the gasifying agent is 20%, it represents the air without any oxygen enrichment. Therefore, nitrogen as a carrier gas is not produced and the entire amount is used as a gasifying agent.

When the carrier gas nitrogen concentration is constant, the gasifying agent acid 1i4a
As the temperature increases, the amount of gas and other agents produced decreases. For example, when the nitrogen concentration of the carrier gas is 99.9% and the oxygen concentration of the gasifying agent is 25%, the ratio of the amount of gas and other agents produced to the amount of raw material gas is 80%, and the remaining 20% is Produced as a carrier gas.

Carrier gas 1! As the elementary concentration decreases, the ratio of the amount of other gases produced to the amount of raw material gas decreases. That is, it is shown that the amount of raw material gas used as a gasifying agent decreases and the amount used as a carrier gas increases.

As mentioned above, the ratio of gasifying agent and carrier gas.

The ratio is preferably about 5:1, and the ratio of the amount of gas and other agents produced to the amount of raw material gas is 80%. In such a case, the oxygen concentration of other gases can be set to about 25%, and the gasification efficiency can be sufficiently increased.

A unique effect of this embodiment is that the pressure at the time of adsorption in the adsorption/desorption towers 11 and 12 is set to a pressure that can supply gas for coal conveyance, so there is no need to further pressurize the gas generated from the PSA. in general.

A compressor is used to pressurize the gas generated in PSA, but as in coal gasification, two types of gas are required: a coal transport gas and an oxidizer; Since the amounts to be processed differ by a factor of about 10, two compressors with significantly different throughputs are required. However, according to this embodiment, only one compressor is required, and moreover, the coal conveying gas and oxidizing agent can be produced using the compressor originally required for gasification. Therefore, compared to a case where a conventional PSA and a coal gasification device are simply combined, the device can be made extremely simple, and the cost for producing oxygen-enriched air is almost eliminated.

Furthermore, in the case where a larger amount of gas than the product gas was disposed of as in the past, the discarded gas was also pressurized, which means that a lot of energy was wasted and wasted. However, in the present invention, since the entire amount of gas is used for gasification without waste, gasification can be performed efficiently. Moreover,
Since the entire amount of gas is used, the entire interior of the air separator can be used, and conversely, the throughput can be met with a much smaller device than in the past.

Further, FIG. 7 shows an example in which a coal gasification apparatus using the present invention is used in a coal gasification combined cycle power generation system.

A coal gasification combined cycle power generation system consists of 1 coal gasifier16.
Gas turbine 110. It consists of air production equipment 11° and 12.

Coal gasifier 1i! 16. and air separation device 11゜12
The gas produced by the coal gasifier is similar to that shown in FIG. 1, and contains unreacted char and harmful sulfur compounds.

Remove unreacted char from cyclones, etc.! In the Q device 101,
After the dust contained in the generated gas is removed and stored in a hopper 102, it is recycled to a gasifier 16 via a feeder 105 in a lock hopper system composed of hoppers 103 and 104. Sulfur compounds contained in the air stream are removed by a desulfurizer 106. Before entering 1106, the temperature of the generated gas is lowered by a heat exchanger 107 to a temperature that facilitates desulfurization.

The dedusted and desulfurized gas is combusted by the gas turbine combustor 108 to drive the gas turbine 110. Further, the combustion gas is combined with the heat exchanger 109 to generate steam, and the steam turbine 111 is driven. The energy obtained by driving these turbines drives the compressor 18 to pressurize the air 4 and use it for gasification and combustion in the gas turbine combustor 108. Do as above.

Gas turbine 110. Highly efficient combined power generation is performed by driving the steam turbines 11 at the same time.

Even a small amount of gas makes it easier to drive the gas turbine 110, which is advantageous for power generation.

Therefore, when electricity is generated by gasification with air, the amount of generated gas is larger than when electricity is generated by gasification with oxygen, so it is easier to generate electricity. However, as mentioned above, in a coal gasifier, the generated heat cannot raise the temperature due to the nitrogen contained in the air, so the ash in the coal cannot be melted, and the combustion reaction must proceed. I don't get it. As a result, combustible gas in the produced gas decreases, reducing gasification efficiency.
This was causing the cost of power generation to rise.

However, by using a system using a coal gasifier according to the present invention, the gasification efficiency can be increased to the level of oxygen gasification without changing the cost of installing an oxidizer compared to conventional air gasification. That is, since all pressurized gases are used, the same amount of gas as in the case of air gasification can be obtained, and all of them can be used for power generation. Furthermore, since gasification is performed with oxygen-enriched air in the gasification furnace, the temperature inside the furnace can be increased and the gasification reaction can be performed with low oxygenation. Moreover, no expense is required to produce oxygen-enriched air. As a result of the above, it is possible to dramatically reduce the cost of power generation.

Furthermore, when considering a power generation system that allows the air separation device to be much smaller than conventional ones, the site area of the plant is directly related to the cost of constructing the power plant.

When using a conventional PSA, it is necessary to insert a PSA for both the carrier gas and the coal conveying gas,
In addition, in PSA, more than half of the layers are stopped for desorption operations, so a very large site area is required. but,
According to the present invention, all of the gas supplied to the PSA is effectively used, so the size can be significantly reduced compared to the conventional one.

Example 2 will be explained using FIG. 8.

The outline of the flow is almost the same as in Example 1, but the operating pressure of the adsorption and desorption towers is lowered to produce oxygen-enriched air.

After the coal conveyance gas is generated, it is intended to be pressurized by boost-up compressors 38 and 39.

PSA is generally performed at low temperature and pressure. This is a P method that uses the difference in equilibrium adsorption amount to separate oxygen and nitrogen from the air.
This is because in SA, the lower pressure allows the adsorbed gas to be desorbed and the performance is better.

A unique advantage of this embodiment is that adsorption and desorption operations are easy.

Next, Example 3 will be explained with reference to FIG. 9.

The outline of the flow is almost the same as in the first embodiment.

The difference in this embodiment is that, first, a buffer tank 41 is placed after the outlet valve 24, 25 for the gas that has completed the adsorption operation, that is, the high-purity nitrogen gas used as the carrier gas.
In addition, a buffer tank 42 was installed after the outlet valve 27, 28 for the gasifying agent after the desorption operation.

Second, after pressurizing the raw material air 4 with the compressor 18,
This is because an adsorption tower 43 filled with an agent for removing moisture is provided.

In PSA, the adsorption/desorption groups A11. The adsorption or desorption operation is performed by changing the pressure inside the adsorption/desorption column B12. Therefore, large pressure fluctuations occur in the outlet gas of the adsorption/desorption group All and the adsorption/desorption group B12.

In addition, at the beginning of the desorption operation, the pressure does not reach the appropriate pressure for desorption, so the oxygen concentration in the oxygen-enriched oxygen is low because the oxygen desorption from the adsorbent is not sufficient, while at the end of the desorption operation, the oxygen concentration is low. On the contrary, since oxygen desorption from the adsorbent is sufficiently performed, the W1 elementary concentration of oxygen-enriched oxygen becomes high.

The buffer tanks 41 and 42 are intended to eliminate fluctuations in the pressure and composition of the generated gas caused by the operations of adsorption and desorption as described above.

Next, the adsorption tower 43 for moisture removal, which is the second modification, will be explained. In general, adsorbents referred to as PSA are sensitive to moisture, and their efficiency is significantly reduced by a small amount of moisture content. Moreover, when adsorption and desorption operations are performed at relatively high pressures as in the present invention, moisture contained in the air condenses and the adsorption/desorption group A
11. The performance of the agent packed inside the adsorption/desorption tower B12 is deteriorated.

Therefore, after pressurizing the raw material air 4, which has the highest pressure in the system, with the compressor 18, an adsorption tower 43 for moisture adsorption is installed.
It removes moisture.

The unique effects of this example are that fluctuations in the pressure and composition of the generated gas caused by adsorption and desorption operations are reduced, and gasifying agents and carrier gases with stable compositions can be supplied at stable pressures, which improves gasification. The advantage is that the operability of the furnace can be improved.

Next, Example 4 will be explained using FIG. 10.

The outline of the flow is almost the same as FIG. 7 in Example 1, the difference being that a large number of adsorption/desorption groups were provided in the air separation device, and the gas generated in the gasifier was used in the desorption operation. .

As described above, PSA alternately repeats adsorption and desorption operations, but this repeated operation causes instability in the outlet gas composition and outlet pressure.

In addition, coal gasifiers originally intended for power generation have a large throughput, and the PSAI group cannot supply all the gas necessary for coal gasification.Therefore, in this example, the 10th
As shown in the figure, a large number of adsorption/desorption towers 130 are installed so that this repeated operation can be carried out continuously at slightly different times.
The point is that This makes it possible to eliminate the instability of the outlet gas composition and the instability of the outlet pressure, which are disadvantages of PSA.

Furthermore, by providing a large number of adsorption/desorption towers 130, load fluctuation can also be improved. If there is only one set of adsorption/desorption towers 130, in order to vary the load, the amount of gas processed by the adsorption/desorption tower 130 itself must be changed. However, changing the amount of gas processed by the adsorption/desorption tower 130 itself requires It is necessary to change the superficial velocity value in the adsorption/desorption tower 130 and the valve switching interval. Such an operating method imposes restrictions on initial design conditions.

On the other hand, by providing a large number of towers as in this embodiment, when the load is lowered, it is possible to cope with load fluctuations by simply reducing the number of towers used accordingly.

Further, a feature of this embodiment is that the gas generated in the gasifier is used in the desorption operation. In FIG. 7, the low grade steam after passing through the steam turbine 111 is transferred to the line 14.
As the low-grade steam guided to the adsorption/desorption tower 130 by the steam turbine, it is possible to use a heat source such as return circulating water from the water-cooled wall of the gasifier in addition to a steam turbine. line 1
The heat source guided by 40 is supplied to the adsorption/desorption tower 130 during the desorption operation of the adsorption/desorption tower 130 . As a result, the a element adsorbed by the adsorbent is more quickly desorbed. In addition, in the present invention, the desorbed gas becomes the gasifying agent for coal gasification, so the gasifying agent is heated further, and the temperature inside the gasifier can be increased, improving the gasification efficiency. be able to.

The unique effects of this embodiment are that the composition and pressure of the generated gas are stabilized, and the efficiency of desorption can be improved, making it possible to separate gases with higher performance.

Next, Example 5 will be described using FIG. 11.

It is conceivable that the performance of oxygen adsorbents will improve significantly in the future. In such a case, it is considered that the size of the adsorption/desorption tower can be dramatically reduced.

Therefore, in this embodiment, a plurality of adsorption/desorption towers were combined into one air separation tower 90.

As an effect unique to this embodiment, by integrating,
The structure can be simplified and operability and driveability can be improved.

〔Effect of the invention〕

According to the present invention, the gasifying agent and the carrier gas can be simultaneously produced from air and used for coal gasification using almost no production energy.

The equipment necessary for gasification can be significantly downsized, and the cost of producing electricity through gasification power generation can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of Example 1, Fig. 2 is a schematic flow of the coal gasifier and the composition of necessary gas, and Fig. 3 is a PSA
Fig. 4 shows the schematic flow of the system combining a coal gasifier and PSA according to the present invention and the composition of the gas sent, and Fig. 5 shows the adsorption composition used in Example 1. The relationship between the adsorption amount of the agent and time, Figure 6, is as follows.
An explanatory diagram of the operating conditions of Example 1, FIG. 7 is a flow of a power generation system using the coal gasifier of Example 1, FIG. 8 is a schematic diagram of Example 2, and FIG. 9 is a diagram of the example. 3, FIG. 10 is a schematic diagram of Example 4, and FIG. 11 is a schematic diagram of Example 5. 1...Coal, 2...Waste gas, 3...Coal gasification product gas, 4...Air, 5...Slag, 10...
Pressure hopper, 11... Adsorption/desorption tower A, 12... Adsorption/desorption tower B, 13... Supply hopper, 14... Rotary feeder, 15... Eductor-116... Coal gasification furnace , 17... Coal burner, 18... Compressor, 23
...Adsorption/desorption tower A product gas switching valve, 24...
Adsorption/desorption tower Bi product gas switching valve, 27...Adsorption/desorption tower A purge gas switching valve, 28...Adsorption/desorption tower B
Purge gas switching valve, 29...adsorption/desorption tower AfI
X gas supply valve! +-5 30...Adsorption/desorption tower B raw material gas supply valve,
ゝAgent Patent Attorney Katsuo Ogawa - 2nd g Lock-O 1 Soba 0 System Vise 30αtcL Fig. 3 Fig. 4 Loa 7/Pano 803gt> wealth f cod charcoal 3.0 pressure f)
30＾t＾ 5th figure ringing time thin 1 60 invitation 7 figure III-Steam Kubin 8th 37 foust 7 nof 5 noon high name 1 90 42 / (rough 1 tank 1st O figure 30・- sucking vagina 1 tower

Claims (1)

[Claims] 1. Generating highly concentrated nitrogen gas by passing pressurized air through a plurality of towers filled with an adsorbent that adsorbs oxygen faster and in large quantities than nitrogen at the same pressure and temperature; Before a large amount of nitrogen begins to be adsorbed on the adsorbent, the pressure of the air passing through the tower is reduced to desorb the oxygen adsorbed on the adsorbent to generate oxygen-enriched air. High concentration nitrogen gas and enriched oxygen air are continuously generated by shifting and repeating the steps.The high concentration nitrogen gas is used for conveying coal and pressurizing the coal filling container, and the enriched oxygen air is used as a coal gasifying agent. coal gasification method used as 2. Generate highly concentrated nitrogen gas by passing pressurized air through multiple towers filled with adsorbents that have a larger equilibrium adsorption amount of oxygen than nitrogen at the same pressure and temperature. Before reaching this point, the pressure of the air flowing through the tower is reduced to desorb the oxygen adsorbed by the adsorbent to generate oxygen-enriched air, and the above operation is repeated in multiple towers at different times to increase the oxygen content. A coal gasification method that continuously generates concentrated nitrogen gas and oxygen-enriched air, uses the highly concentrated nitrogen gas for conveying coal and pressurizing a coal-filled container, and uses enriched oxygen air as a coal gasification agent. 3. Generate highly concentrated nitrogen gas by passing pressurized air through multiple columns filled with adsorbents that adsorb oxygen faster and in large quantities than nitrogen at the same pressure and temperature, and a large amount of nitrogen is absorbed into the adsorbents. Before the adsorption begins, the pressure of the air flowing through the tower is reduced to desorb the oxygen adsorbed by the adsorbent to generate oxygen-enriched air, and the above operations are performed in multiple layers at different times. An air separation device that continuously generates high-concentration nitrogen gas and oxygen-enriched air by repeating the process; A coal gasifier consisting of a furnace that gasifies coal using oxygenated air as a coal gasifying agent. 4. Generate highly concentrated nitrogen gas by passing pressurized air through multiple towers filled with adsorbents that have a larger equilibrium adsorption amount of oxygen than nitrogen at the same pressure and temperature. Before reaching this point, the pressure of the air flowing through the tower is reduced to desorb the oxygen adsorbed by the adsorbent to generate oxygen-enriched air, and the above operation is repeated in multiple towers at different times to increase the oxygen content. An air separation device that continuously generates concentrated nitrogen gas and oxygen-enriched air, and a furnace that gasifies coal by using the highly concentrated nitrogen gas generated by the device to convey coal and pressurize a coal filling device. A coal gasifier consisting of: