JPS621435A - Treatment of gas by dry moving bed - Google Patents

Abstract

PURPOSE:To attain the conservation of energy, by transporting the absorbent discharged from a desulfurization tower by a part of purified gas and collecting the same by the cyclone in the upstream side of a regeneration tower and recirculating purified gas into gas obtained by the gassification of coal. CONSTITUTION:H2S in gas obtained by the gassification of coal is removed by the absorbent such as FeO received in a moving bed type desulfurization tower 1 and discharged from a line 3 as purified gas. The absorbent converted to FeS by the absorption of H2S and containing dust is fallen through the desulfurization tower 1 and sent to the intiroducing part of a gas transport line 8 from a line 6 while dust is separated by a screen 5. The aforementioned purified gas sends the absorbent to a cyclone 11 where the adsorbent is separated to be sent to a regeneration tower 14 and contacted with O2-containing gas to be regenerated. The gas separated from the absorbent passes through a line 12 to be recirculated to the line 2 into which the gas obtained by the gassification of coal is sent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dry moving bed gas treatment method capable of desulfurizing coal gasification gas.

[Prior art] In the conventional dry gas treatment method, H2S in coal gasification gas is absorbed by a particulate absorbent such as FeO stored in a desulfurization tower at about 460°C, and dust is removed. Purified gas is produced by absorbing 'H28 and F
The absorbent that has become eS and contains dust descends through the desulfurization tower and is fed into a sieve, where the sieve separates the dust from the absorbent.The absorbent from which the dust has been separated is transported upwards by a packet elevator, and is then sent to the sieve. The absorbent is put into a heater from the elevator, heated to a temperature of about 400°C that can be regenerated by the heater, and the heated absorbent is introduced into the regeneration tower, where it comes into contact with the 02-containing gas to remove the sulfur content. is SO2
It is removed as FeO and recycled to FeO. Since the absorbent is at a high temperature of about 800° C. due to the heat of reaction in the regeneration tower, it is cooled to a predetermined temperature by a cooler and returned to the desulfurization tower.

[Problems to be Solved by the Invention] However, in the conventional means described above, the temperature of the absorbent decreases while it is sieved and transported by a packet elevator, so it is necessary to reheat it during regeneration. In addition, a packet elevator is used as a means of transporting the absorbent, and since the packet elevator is difficult to seal at high pressure, the pressure inside the desulfurization tower or regeneration tower is In order to maintain the pressure at a high pressure, valves and hoppers are required, which causes problems such as the equipment becoming larger and more bulky.

[Means for Solving the Problems] The present invention provides a dry moving bed in which an absorbent that has absorbed hydrogen sulfide from coal gasification gas is discharged from a desulfurization tower, sent to a regeneration tower, and regenerated with an oxygen-containing gas. In the gas treatment method, the absorbent discharged from the desulfurization tower is transported as a gas using a part of the purified gas purified in the desulfurization tower, and the absorbent is separated from the purified gas using a cyclone on the upstream side of the regeneration tower, and the absorbent is separated. The purified gas is circulated into the coal gasification gas sent to the desulfurization tower.

[Function] The absorbent that absorbed hydrogen sulfide from the coal gasification gas in the desulfurization tower is taken out from the desulfurization tower, transported by a part of the purified gas purified in the desulfurization tower, and separated in a cyclone. The purified gas is supplied to the post-regeneration tower, and the sulfur content is removed by contacting with oxygen-containing gas, and the purified gas from which the absorbent is separated in the cyclone is circulated into the coal gasification gas supplied to the desulfurization tower.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

The figure shows one embodiment of the present invention, in which 1 is a moving bed desulfurization tower containing particulate absorbent such as FeO, 2 is a line for feeding coal gasification gas to the desulfurization tower 1, 3 is a line that feeds the purified gas purified in the desulfurization tower 1 to the downstream side, 4 is a line that takes out the absorbent from the desulfurization tower 1, and 5 is a line that sieves the absorbent that has descended from line 4, 6 is a line that sends the absorbent separated by the FJ5 to the introduction part 7 of the gas transport line 8; 9 is a line that takes out a part of the purified gas in the line 3 and pressurizes it with a blower 10; A line for feeding the gas to the gas transportation line 8, a cyclone 11 for separating the absorbent from the gas sent through the gas transportation line 8, and a cyclone 12 for separating the gas from which the absorbent has been separated by the cyclone 11. A line 13 is a line that circulates the coal gasification gas to the line 2, a line 13 is a line that feeds the absorbent separated by the cyclone 11 to a moving bed regeneration tower 14, and a line 15 is a regeneration tower 14 for use in regenerating the absorbent. A line 16 for feeding the O2-containing gas introduced into the S0
A line for discharging regeneration gas containing 2 from the regeneration tower 14,
11 is a line for returning the absorbent regenerated by the regenerator 14 to the desulfurization tower 1; and 18 is a cooler provided in the inlet 17. Each of the above-mentioned devices and lines is sealed so that the internal pressure can be maintained at high pressure.

HzS in the coal gasification gas supplied from line 2 to desulfurization tower 1 at approximately 460°C and 20kO/Cm2 is
Dust in the coal gasification gas is also removed by the absorbent, and sent to the line 3 as purified gas. The reaction in the desulfurization tower 1 at this time is carried out as follows.

Fe O+H2S-+Fe S+H20 On the other hand, the absorbent that absorbs H2S to become FeS and contains Das 1 is
It descends from the desulfurization tower 1 and is discharged to line 4, and is sent from line 4 to sieve 5, where the absorbent and dust contained in the absorbent are sieved and separated, and the dust The absorbent from which the gas has been removed is sent from the line 6 to the inlet 7 of the gas transport line 8, and is supplied into the gas transport line 8.

The purified gas branched from line 3 to line 9 is sent to blower 10.
The absorbent is pressurized and supplied to the gas transport line 8 , and the absorbent introduced into the gas transport line 8 is transported as a gas and sent to the cyclone 11 .

In the cyclone 11, the absorbent is separated from the gas and fed through a line 13 to a regeneration tower 14, where it comes into contact with the 02-containing gas fed from a line 15 to perform regeneration. Since the absorbent maintains the temperature necessary for regeneration even after being separated by the cyclone 11, it can be regenerated. There is no need to heat it before birth. The reaction during regeneration is performed as follows.

2Fe S+302-2Ff30+2SO2 Since heat is generated by the above reaction during regeneration, the regenerated absorbent is at a high temperature. Therefore, the absorbent is cooled to a predetermined temperature in the cooler 18 and then returned to the desulfurization tower 1 through the supply line 17. 80 discharged from the regeneration tower 14 to line 16
The regeneration gas containing 2 is sent to a reduction tower (not shown), and S0
2 is reduced and most of it becomes elemental sulfur.

The gas from which the absorbent has been separated by the cyclone 11 is transferred to the line 12.
through which the coal gasification gas is circulated into line 2. By circulating the gas in this manner and preventing it from being discharged to the outside, sulfur content is not discharged into the atmosphere, thereby preventing air pollution and damage to various equipment.

In addition, in the examples of the present invention, FcO was used as an absorbent.
Although we explained the case of using ZnO, CuO
It is possible to use metal oxides such as, carrier + iron oxide, mixtures of fly ash and iron oxide, etc., and various changes can be made without departing from the gist of the present invention.
Of course, etc.

[Effects of the invention] According to the dry moving bed gas treatment method of the present invention, there is no need to reheat the absorbent during regeneration, which contributes to energy saving, and the entire line can be used under high pressure, so the high pressure section and normal pressure section The line is simplified because there is no need for hoppers, valves, etc. to connect the gas, the price is lower because there is no need to install separate gas equipment for transportation, and safety is improved because the gas is not emitted into the atmosphere. Various excellent effects can be achieved.

[Brief explanation of the drawing]

The figure is an explanatory diagram of one embodiment of the present invention.

Claims (1)

[Claims] 1) In a dry moving bed gas treatment method in which an absorbent that has absorbed hydrogen sulfide from coal gasification gas is discharged from a desulfurization tower and sent to a regeneration tower where it is regenerated with oxygen-containing gas, the absorbent discharged from the desulfurization tower Coal gas where the absorbent is transported as part of the purified gas purified in a desulfurization tower, the absorbent is separated from the purified gas by a cyclone on the upstream side of the regeneration tower, and the purified gas from which the absorbent has been separated is sent to the desulfurization tower. A dry moving bed gas treatment method characterized by circulating the gas into a chemical gas.