JPS5811711A - Method for reducing steam consumption in co conversion of converter waste gas - Google Patents

Abstract

PURPOSE:To reduce a charging quantity of steam, by performing the temp. controlling of the inside of a catalyst tank by an indirect water cooling device provided to the inside of the tank. CONSTITUTION:Raw gas i.e. a converter waste gas, after subjecting to a CO- conversion in a catalyst tank 1 by the action of steam, is sent i.e. to a CO2 separating device 2 of an adsorbing tower system, and here the CO2 is separated and recovered. For the temp. controlling of the tank 1, water is fed indirectly into an indirect water-cooling device provided to the tank 1. Hot water, coming out from the tank 1, is introduced into the device 2 to be utilized for an indirect heating of the device 2, and then is circulated to be utilized for the cooling of the tank 1 again. Gaseous H2 without containing CO2 is sent to a H2 separating device 3 from the device 2 to separate and recover the H2 by an adsorbent. Accordingly the need of the steam for the temp. controlling of the tank 1 is eliminated thereby reducing the steam consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing carbon dioxide and water bulk from converter exhaust gas. More particularly, the present invention relates to a method for reducing the amount of water vapor input into the catalyst tank as a CO conversion system used in the above method.

Converter exhaust gas discharged from steelmaking converters such as pure oxygen top-blown converters generally contains carbon monoxide (CO) as a main component, with a small amount of carbon dioxide (CO□).

Contains nitrogen (N, ) and water volume (Hl). This C
O conversion (water gas reaction, i.e. CO+) I! 0→Co
t + Hs) and Cot and Hlt- production can be carried out.

When this method is operated industrially, the catalyst tank has a volume ratio of
In other words, the amount of raw material gas in terms of molar ratio is 21~aO.
It accounts for a large percentage of the total. Therefore, the savings in steam input greatly contributes to the economics of this method.

As is clear from the above reaction formula, KCO conversion is an equimolar reaction, and the reaction requires only an equimolar amount of water vapor as the theoretical amount of KFiCO. For this reaction, the amount of raw material gas is 11-40
The reason for introducing twice the molar amount of steam is to increase the CO conversion rate and the subsequent CO.

To maintain the heat balance in the separation process, approximately twice the mole of water vapor is required for the reaction itself, and on the other hand, the temperature of catalysts such as iron oxide rises too much due to the reaction heat generated by the CO conversion reaction. This is because α1-10 times the molar amount of K, which prevents this by the sensible heat of water vapor, is required.

In other words, catalysts such as iron oxide suddenly lose their activity when the temperature exceeds a certain limit (approximately 550°C in the case of iron oxide), and not only do they cease to function as a catalyst, but one catalyst also deteriorates. It is necessary to constantly control the temperature of the kernels to a lower temperature than the limit temperature of the kernels, and conventionally this temperature control has been carried out by appropriately increasing or decreasing the amount of water vapor input.

The present inventors have arrived at the present invention as a result of intensive study on a method for controlling the temperature of a catalyst tank without relying on expensive steam and reducing the operating cost of a CO conversion reaction.

Here, 1. The present invention is to convert CO by making steam act on the converter exhaust gas in a catalyst tank, but when producing carbon dioxide and hydrogen, 1. This is a method for reducing the amount of water vapor in CO conversion of converter exhaust gas, which is characterized by reducing the amount of water vapor input by using an indirect water cooling device.

As a means of cooling the catalyst tank, the first idea is to directly inject water and use its sensible and latent heat to cool the tank, but this method cannot be used because it causes the catalyst to become powder, resulting in deterioration of the catalyst. The present inventors have found that by installing a water cooling device (for example, a boiler type) using indirect water in the catalyst tank and controlling the temperature of the catalyst tank by increasing or decreasing the amount of water, the performance and reaction of the catalyst can be improved. It has been discovered that the desired temperature control can be successfully achieved without any adverse effects. Moreover, the heated cooling water can be used in the subsequent COI separation process, and in such a case, in addition to reducing the amount of water and M air input to the catalyst tank, it also reduces the amount of heat supplied to the CO and separation equipment. The amount can be reduced by 4. A double saving effect can be obtained. That is, the cooling water that has become hot water is separated by, for example, Cot.
After being cooled and used for indirect heating in a reboiler,
It may be used again for cooling the catalyst tank, or #'i
It may be directly introduced together with an aqueous absorption solution into a CO3 separation device consisting of a co, a collection tower.

In addition, in the present invention, Ha and CO are converted by CO conversion.
1 can be obtained efficiently and at low cost. Therefore, the present invention combines scale φ4→4CO with a converter steelmaking process that uses bottom blowing. It has excellent effects, such as making it possible to reuse small quantities of steel, which greatly contributes to improving the efficiency of the entire S steel process and reducing costs.

The invention will now be further described with reference to one of the accompanying drawings.

Figure 1 shows how hot cooling water is converted into CO! This is a flow sheet showing one embodiment of the method of the present invention used in a separation device, in which the raw material gas (converter exhaust gas) undergoes CO conversion through the action of water vapor in a catalyst tank 1.
According to the present invention, an indirect water cooling device (not shown) is provided in catalyst tank 1 to control the temperature of catalyst tank l, and CO2 is separated and recovered there. is indirectly fed into the catalyst tank. The hot water coming out of the catalyst tank 1 is introduced into the CO8 separator, used for indirect heating of the CO1 separator, and then used again in small amounts to cool the catalyst tank. The CO-free gas coming out of the CO separator is then sent to the H1 separator 11, where H1 is separated and recovered using, for example, an adsorbent (e.g., synthetic zeolite). Off-gas from the straw racks is used for fuel, etc.

FIG. 8 graphically shows the amount of water vapor required for the method of the present invention and the conventional method in relation to the amount of raw material gas. The CO concentration in the raw material gas is 66%9, and the conventional method of controlling the temperature of the catalyst tank by increasing or decreasing the amount of water vapor input,
As shown in the figure, in addition to the required amount of steam for the plant, which is about 8 times the amount of raw material gas, the amount of steam shown in the shaded area in the diagram is required for one heating house control. According to this, the rounded water vapor for temperature control becomes unnecessary, so the amount of water vapor in the shaded area is saved.

The present invention will be specifically explained below using one example.

Example Converter exhaust gas containing about 66% CO 45ONj/h
As the rf raw material gas, CO conversion was performed in an iron oxide catalyst tank according to the method of the present invention. The catalyst tank is operated at a pressure of 1 ata, and is supplied with steam at a temperature of 860°C.
hr (approximately 9001j &//hr) and CO.

And H8 is generated, and the indirect cooling device for the catalyst tank is heated.
The outlet temperature of the catalyst vessel was maintained at 460°C by passing water at 20°C at a pressure of 1D17ata. The temperature of the cooling water that passed through the catalyst tank cooling device was 170°C. Under these conditions, the greenhouse maintenance of the catalyst tank requires approximately 86.8111/hr.
indirect cooling water was required.

On the other hand, if an attempt is made to maintain the outlet temperature of the catalyst tank at 450°C using steam at 850°C without using an indirect cooling device, the output temperature will be approximately 818 KMhr (approximately 1080 Nwl/hr
) had to be input into the catalyst tank.

Therefore, in this case, the method of the present invention saves about 1054/hr (about 181 Nl//hr) of water vapor compared to the conventional method. Moreover, in the method of the present invention, hot water of 17G) °C can be obtained at an amount of about 868 Kr/hrO.
There is a double advantage in that the heat value of this hot water can be recovered in the subsequent CO1 separator.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an outline of the method of the present invention, and FIG. 2 is a graph showing the relationship between the amount of steam input and the amount of raw material gas in the method of the present invention and the conventional method. In No. 111, 1...catalyst tank, 2...CO3 separation device, 8...H1 separation device. Patent applicant: Sumitomo Metal Industries, Ltd. Kyodo Sanso Co., Ltd. Agent: Patent attorney Akira Hirose

Claims (1)

[Claims] When producing carbon dioxide and hydrogen, the temperature in the catalyst tank is controlled by a nine-way water cooling system installed in this tank. It is characterized by reducing the amount of water vapor input by
A method for reducing the amount of water vapor in CO conversion of converter exhaust gas.