JPS62167390A - Method for treating by-product gas - Google Patents

Abstract

PURPOSE:To obtain a high-calorie gas at low cost, by passing a by-product gas through gas permeable membranes at plural stages having CO/CO2 preferentially separating properties to separate and remove a CO2 component and moving the resultant gas through a gas absorbing column to give concentrated CO. CONSTITUTION:A by-product gas from which dust is removed by a filter 1 is passed through gas permeable membranes (e.g., dimethyl silicon membrane, fluorine-containing olefin siloxane copolymer membrane, polycarbonate/ polysiloxane membrane, etc.,) 2a and 2b at plural stages, having preferentially separating properties to separate and remove its CO2 component. Then, the resultant gas is moved through a gas absorbing column 3 to give concentrated CO.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for treating by-product gas generated in a steel mill or the like, and more particularly to a method for increasing the calorie content of the by-product gas.

[Conventional technology and its problems]

Steelworks generate byproduct gases such as coke oven gas, blast furnace gas, and converter furnace gas. This type of by-product gas, with the exception of coke oven gas, has a relatively low calorie, and blast furnace gas in particular has a very high content of N, Co, and other components, and has extremely low utility value as a fuel.

Such N, , and co in blast furnace gas can be removed by a wet method such as the so-called Cosorb method, but the wet method has a problem in that it is expensive and unprofitable. On the other hand, it is also possible to use the so-called pressure fluctuation gas adsorption method (hereinafter referred to as P8A), which is known as a dry method, but this PEA does not have sufficient ability to simultaneously separate CO and COl, and in the end, a two-stage method is used. Equipped with PEA equipment, COl
There is no choice but to adopt a method of first separating Co and then concentrating Co, or a method of processing in combination with a wet method.

In view of these conventional problems, the present invention aims to provide a method that can remove N, , Go, and other components from by-product gas such as blast furnace gas at low cost and increase the calorie content of the by-product gas. It is something to do.

[Means to solve the problem]

Therefore, the present invention focuses on the existence of a gas permeable membrane that has a gas selective separation property of Co, /Co, and by combining the CQ and separation by such a gas permeable membrane and Co concentration by a gas adsorption tower, high calorie gas can be removed. We have developed a method that can be obtained efficiently.

That is, in the present invention, the by-product gas is passed through a multi-stage gas permeable membrane having a selective separation property of Co and /C0 to separate and remove its Co and components, and then passed through a gas adsorption tower to be concentrated. Its basic feature is that it obtains Co.

FIG. 1 shows the basic configuration of equipment for carrying out the method of the present invention.

By-product gases such as converter gas and blast furnace gas are passed through a gas permeable membrane (2) with CO, /Co selective separation characteristics after dust is removed by a filter (1), and their Co and other components are separated. removed. This gas permeable membrane allows specific gas components to permeate selectively by diffusing gas molecules through the membrane, and its characteristics are determined by the ratio of the amount of permeation between the two gas components. Separation factor (e.g. Co,
/CO 4).

This type of gas permeable membrane has the problem that when its separation characteristics increase, the gas permeability coefficient decreases and the treatment efficiency deteriorates. Therefore, in the present invention, the relatively small CO2/
CO is removed by providing multiple stages of gas permeable membranes that selectively separate CO and allowing the by-product gas to pass through these gas permeable membranes in sequence.
, and to ensure effective separation of gas and gas treatment effects. In Figure 1, two stages of gas permeation membranes (2a) (2b) are provided, and by-product gas is passed through the first gas permeation & (2sL
) and the second gas permeable membrane (2b), and CO! components are removed.

As the gas permeation@(2), for example, a dimethyl silicone film, a fluorine-containing olefin-siloxane copolymer film, a polycarbonate/polysiloxane film, a vinyl chloride/liquid crystal fluorocarbon film, etc. are used. (PαWψ−)・The separation characteristics of the silicon film are as follows.

(Gas component) / (Gas component) Selective separation coefficient 0, /N
, 2 Co, / H, 4,9 Co, / Co 9.0 The by-product gas from which most of the CO components have been removed is P.
The gas is passed through a gas adsorption tower (3) using the SA method or the like, whereby gas components other than the CO component, especially N, pass through, where Co is adsorbed and concentrated, resulting in a gas with a high CQ of 9 degrees. The gas adsorption tower (3) and the adsorbent used here can be conventional ones. Synthetic zeolite is usually used as this adsorbent. Figure 2 shows the Co, N, and separation characteristics of this type of adsorbent (CO selectivity (dynamic adsorption amount of CO)/((dynamic adsorption amount of CO) + (dynamic adsorption amount of Ns))) This shows that.

Furthermore, in Fig. 1, the gas permeable membrane (2a) (zb
) and a blower (5) on the inlet side of the separator (4).
), vacuum pumps (6) (7) are installed on the outlet side, and a compressor (8) is installed on the inlet side of the gas adsorption tower (3).
) is provided.

〔Example〕

Converter gas Table 1 shows the gas composition and gas amount at each position (■, ■ to ■) in the figure when the converter gas is treated with the equipment shown in FIG. In the equipment shown in FIG. 3, a dimethyl silicone membrane is used for the two-stage gas permeable membrane (2m) (2b). Further, (9) is a catalytic combustor.

Table 1 B and Blast Furnace Gas Table 2 show the gas composition and gas amount at each position in the figure when blast furnace gas was treated with the equipment shown in FIG. In this case as well, a dimethyl silicon film is used as the gas permeation a (21) (2b).

Table 2 [Effects of the Invention] As described above, according to the present invention, the so-called dry method
This method has the effect of appropriately separating and removing gas components such as 01, etc., and obtaining high-calorie gas at low cost.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the basic configuration of equipment for carrying out the method of the present invention. Figure 2 shows Go of the gas adsorbent used in the present invention.
, N indicates separation characteristics. FIG. 3 is an explanatory diagram showing the processing equipment used in the example. In the figure, (2a,) (2b) are gas permeable membranes, (3)
is a gas adsorption tower.

Claims (1)

[Claims] In a method for processing by-product gas containing CO_2 and CO,
The CO_2 is removed by passing the by-product gas through a multi-stage gas permeable membrane with CO_2/CO selective separation.
The components are separated and removed, and then passed through a gas adsorption tower,
A method for processing by-product gas, characterized by obtaining concentrated CO.