CN111704107A

CN111704107A - Process for preparing synthesis gas by using ore-smelting furnace gas

Info

Publication number: CN111704107A
Application number: CN202010415522.3A
Authority: CN
Inventors: 杨皓; 田森林; 钟俊波; 宁平
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-05-16
Filing date: 2020-05-16
Publication date: 2020-09-25

Abstract

The invention discloses a process for preparing synthesis gas by using submerged arc furnace gas, wherein the submerged arc furnace gas is ferroalloy tail gas, calcium carbide furnace tail gas, yellow phosphorus furnace tail gas and zinc smelting tail gas, the tail gas (dry basis) contains more than 50% of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag is high-concentration carbon dioxide gas separated by a decarburization device; compressing and transforming the dust-removed gas and separating carbon dioxide; the content of separated carbon dioxide (dry basis) is more than 90 percent, and the concentration of combustible gas is lower than 3 percent; after the carbon dioxide gas is dried, the saturation humidity reaches below 80 percent, thereby replacing the technique of commonly used nitrogen for bag back blowing.

Description

Process for preparing synthesis gas by using ore-smelting furnace gas

Technical Field

The invention relates to the fields of metallurgy, energy conservation and environmental protection, and discloses a method for effectively reducing waste discharge and resource consumption.

Background

Usually, the gas of the ore-smelting furnace contains nitrogen. The main source of nitrogen is bag-type back-blowing gas, and the back-blowing gas is usually produced by pressure swing adsorption.

Yanghao CN109627134A announces a methanol synthesis gas preparation technology of ferroalloy smelting coal gas, its characterized in that: 1-5% of hydrogen, 60-80% of carbon monoxide, 3-15% of carbon dioxide, 0.1-2% of methane, 5-16% of nitrogen and 0.1-0.8% of oxygen are called as smelting gas, 60-80% of the smelting gas is mixed with methanol purge gas, the concentration of carbon monoxide in the mixed gas reaches below 50%, the intensity of conversion is favorably reduced, the concentration of carbon monoxide is less than or equal to 3% and becomes conversion gas, the conversion gas is subjected to pressure swing adsorption decarburization to prepare pure hydrogen and recover carbon monoxide, 20-40% of the smelting gas is subjected to non-conversion desulfurization to become purified smelting gas, the purified smelting gas and the pure hydrogen are mixed to be used as methanol synthesis gas, and the percentage adjustment of the non-converted smelting gas is used as a means for controlling the temperature of a methanol synthesis tower. .

The coal gas dust removal system of the submerged arc furnace is disclosed by Zhongzhen Xintai new material science and technology company Zhongxu Dong CN206549389U, and comprises three settlers, a suction fan, three bag-type dust collectors and a clean air fan; the air outlet of the settler at the tail end is connected with the air inlet of the suction fan; the air outlet of the air suction fan is respectively connected with the air inlets of the three bag-type dust collectors; the air outlets and the air inlets of the three settlers are sequentially connected step by step through pipelines; the air outlets of the three bag-type dust collectors are connected with the air inlet of the air purifying fan; the device also comprises a settling ash bin and a dedusting ash bin; the discharge ports of the three settlers are communicated with the sedimentation ash bin through pipelines, and the ash outlets of the three bag-type dust collectors are communicated with the dedusting ash bin through pipelines.

CN203711406U of Wang Xueli et al, Ningxia Sen heavy industry equipment Limited company, announces a submerged arc furnace gas blowback ash removal device, including: a motor, a rotating shaft and a jacket inflator; wherein, the jacket gas cylinder includes: the device comprises a motor mounting seat, a back-blowing gas inlet, an inner-layer inflator, a purified gas outlet, a jacket layer and a rotary back-blowing part; the inner layer inflator is cylindrical with an open lower end, the lower end of the inner layer inflator is communicated with the rotary back blowing part and is rotationally fixed, and the transmission shaft is connected with the flange through a tapered roller bearing; the lower end of the inner layer inflator and the rotary back-blowing part are sealed by adopting a double-channel oil seal. The utility model uses the tapered roller bearing to replace the previous shaft sleeve to fix the transmission shaft, thus reducing the radial swing and axial float of the rotary back-blowing part; the double-channel oil seal is arranged to reduce the gas leakage by more than 95%.

The above patent generally adopts nitrogen as the blowback gas of a bag-type dust collector in the gas collection process of the recovery and utilization process of the tail gas of the submerged arc furnace. The reason for this is that nitrogen gas can be obtained inexpensively by a pressure swing adsorption air separation apparatus, and metal dust and nitrogen gas do not form a metal compound at 300 ℃ or lower. Ensuring the safety. The use of nitrogen blow-back and mechanical seals allows nitrogen to enter the purified submerged arc furnace gas, which is particularly preferred if nitrogen is used as the synthesis gas feed. However, when nitrogen is used as an inert gas in the synthesis process, the nitrogen is difficult to separate from the synthesis gas.

In fact, some enterprises use the purified tail gas of the submerged arc furnace in the back blowing process, the risk lies in that the tail gas contains high-concentration carbon monoxide, the potential safety hazard of the back blowing gas supply process can be caused, and the tail gas of the submerged arc furnace cannot be used when the mechanical seal is used for emptying.

The common pressure swing adsorption separation adsorbent is difficult to adsorb hydrogen, nitrogen, carbon monoxide, methane, carbon dioxide, water and hydrogen sulfide in sequence. Carbon dioxide is much more readily adsorbed than nitrogen.

Disclosure of Invention

A process for preparing synthetic gas by using submerged arc furnace gas is characterized in that the submerged arc furnace gas is ferroalloy tail gas, calcium carbide furnace tail gas, yellow phosphorus furnace tail gas and zinc smelting tail gas, the tail gas (dry basis) contains more than 50% of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag is high-concentration carbon dioxide gas separated by a decarburization device; compressing and transforming the dust-removed gas and separating carbon dioxide; the content of separated carbon dioxide (dry basis) is more than 90 percent, and the concentration of combustible gas is lower than 3 percent; after the carbon dioxide gas is dried, the saturation humidity reaches below 80 percent, thereby replacing the technique of commonly used nitrogen for bag back blowing.

The method takes the carbon dioxide separated from the shift gas as the bag-type back flushing gas to prevent the introduction of nitrogen in the gas of the dedusting and ore-smelting furnace, thereby reducing the introduction of nitrogen in the synthetic gas, reducing the separation proportion of nitrogen in the synthetic gas and even possibly removing the denitrification process.

As carbon dioxide is also generated in the conversion process, and the carbon dioxide introduced in the back blowing process and the carbon dioxide generated in the conversion process are removed in a synergistic manner, the synthesis gas discharged after the whole submerged arc furnace gas is used for preparing the synthesis gas is reduced, and the energy consumption is saved.

Detailed Description

Example 1: the coal gas of the ore-smelting furnace is ferrosilicon tail gas, the tail gas (dry basis) contains 95 percent of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag adopts high-concentration carbon dioxide gas separated by a decarburization device; compressing the decarbonized gas to 2.5MPa, separating carbon dioxide by PSA after transformation, wherein the carbon dioxide concentration of the decarbonized gas is 11 percent and the pressure of the decarbonized gas for synthesizing methanol is 4.0 MPa; the content of separated carbon dioxide (dry basis) is 98.5 percent, the concentration of methane gas is 1 percent, and the content of nitrogen is 0.5 percent; after the carbon dioxide gas is dried, the saturation humidity reaches 70%, and when the dedusting ore-smelting furnace gas (dry basis) is delivered, 89% of carbon monoxide, 10% of carbon dioxide and 1% of the rest. Therefore, compared with the methanol synthesis pressure of 5.0MPa in the nitrogen back blowing process, the effective gas partial pressure in the synthesis process is unchanged, and the synthesis pressure is reduced by 1.0MPa under the condition that the total amount of purge gas is unchanged, so that the consumption of ton of alcohol is reduced.

Example 2: the coal gas of the ore-smelting furnace is ferronickel tail gas, the tail gas (dry basis) contains 92% of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag is high-concentration carbon dioxide gas separated by a decarburization device; compressing the decarbonized gas to 1.5MPa, separating carbon dioxide by PSA after transformation, wherein the carbon dioxide concentration of the decarbonized gas is 8 percent and the pressure of the decarbonized gas is 5.0MPa for synthesizing methanol; the content of separated carbon dioxide (dry basis) is 98.9 percent, the concentration of methane gas is 0.6 percent, and the content of nitrogen is 0.5 percent; after the carbon dioxide gas is dried, the saturation humidity reaches 20%, and when the dedusting ore-smelting furnace gas (dry basis) is delivered, 91% of carbon monoxide, 8% of carbon dioxide and 1% of the rest. Therefore, the methanol synthesis pressure in the nitrogen back-blowing process is improved to be 5.0MPa, the effective gas partial pressure is unchanged in the synthesis process, the total amount of purge gas is reduced by 90%, and the methanol productivity is increased by 10%, so that the methanol consumption per ton is reduced.

Example 3: the coal gas of the ore-smelting furnace is tail gas of a calcium carbide furnace, the tail gas (dry basis) contains 95 percent of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag adopts high-concentration carbon dioxide gas separated by a decarburization device; compressing the decarbonized gas to 0.8MPa, separating carbon dioxide by PSA after transformation, wherein the carbon dioxide concentration of the decarbonized gas is 8 percent and the pressure of the decarbonized gas is 5.0MPa for synthesizing methanol; the content of separated carbon dioxide (dry basis) is 96.7 percent, the concentration of methane gas is 0.6 percent, carbon monoxide is 2.2 percent, and nitrogen is 0.5 percent; after the carbon dioxide gas is dried, the saturation humidity reaches 2%, and when the dedusting ore-smelting furnace gas (dry basis) is delivered, 91% of carbon monoxide, 8% of carbon dioxide and 1% of the rest. Therefore, the methanol synthesis pressure in the nitrogen back-blowing process is improved to be 5.0MPa, the effective gas partial pressure is unchanged in the synthesis process, the total amount of purge gas is reduced by 90%, and the methanol productivity is increased by 10%, so that the methanol consumption per ton is reduced.

Claims

1. The invention relates to a process for preparing synthesis gas by using submerged arc furnace gas, which is characterized by comprising the following steps of: the gas of the ore-smelting furnace is ferroalloy tail gas, calcium carbide furnace tail gas, yellow phosphorus furnace tail gas and zinc smelting tail gas, the tail gas (dry basis) contains more than 50 percent of carbon monoxide, the tail gas is called as dust removal gas through cloth bag dust removal, and the back blowing gas of the cloth bag is high-concentration carbon dioxide gas separated by a decarburization device; compressing and transforming the dust-removed gas and separating carbon dioxide; the content of separated carbon dioxide (dry basis) is more than 90 percent, and the concentration of combustible gas is lower than 3 percent; after the carbon dioxide gas is dried, the saturation humidity reaches below 80 percent, thereby replacing the technique of commonly used nitrogen for bag back blowing.