CN1488735A

CN1488735A - Sponge iron efficient desulfurizing agent

Info

Publication number: CN1488735A
Application number: CNA021311307A
Authority: CN
Inventors: 杰王; 王杰; 李钢; 刘庄; 宋宝英
Original assignee: TIANJIN STEL PIPE REDUCED IRON PLANT
Current assignee: TIANJIN STEL PIPE REDUCED IRON PLANT
Priority date: 2002-10-11
Filing date: 2002-10-11
Publication date: 2004-04-14
Anticipated expiration: 2022-10-11
Also published as: CN1249208C

Abstract

The present invention relates to a sponge iron high-effective desulfurizer for removing hydrogen sulfide gas, its composition includes (wt%) 40%-50% of sponge iron, 10%-20% of sawdust, 1%-10% of lime hydrate and 30%-40% of gypsum. Said invention can obtain good desulfurizing effect, its average desulfurizing efficiency can be up to above 95%, and said desulfurizer can be regenerated for reuse.

Description

High-efficiency sponge iron desulfurizer

Technical Field

The invention relates to a desulfurizer for removing hydrogen sulfide gas in coke oven gas, oil-produced gas and chemical products, in particular to a desulfurizer for removing hydrogen sulfide gas, which is prepared by using sponge iron as a main material.

Background

The process is accompanied with the discharge of hydrogen sulfide gas in the production process of gas generators, coke oven gas furnaces, oil-gas-making furnaces and other chemical products, and the hydrogen sulfide gas is harmful to human beings and pollutes the environment. In order to remove hydrogen sulfide gas during the production process, various dry desulfurizing agents are available. The dry desulfurizing agent in China is prepared from iron-containing main materials, such as converter red mud, cast iron scraps, and pyrite, but the desulfurizing agent prepared from the materials has the following defects:

1. the composition is unstable. Because iron-containing components in the converter red mud and the marcasite are unstable, particularly the converter red mud is from waste materials in the converter steelmaking production process, the waste materials contain a lot of impurities, and because of different steelmaking processes, the iron content in the converter red mud is also unstable, and the variation range is large, so that the components of the desulfurizer taking the converter red mud as the raw materials are unstable; the main component of the marsh iron ore is equivalent to Fe₂O₃·3 H₂O, but Fe contained therein due to different amounts of sand and organic matter₂O₃The range is wide and is from 20 to 78 percent; but also contains a large amount of phosphate, and the desulfurization effect cannot be ensured.

2. The service cycle is short. The existing strip-shaped desulfurizer is relatively compact, low in porosity and small in reaction contact area, so that the sulfur capacity is small and is different from 5-10% to 20-40%, and therefore, the desulfurization efficiency is low and the service cycle is short.

Disclosure of Invention

The invention aims to overcome the defects of the technology and provide a high-efficiency desulfurizer which utilizes sponge iron with stable iron-containing components, high porosity and good adsorption property as hydrogen sulfide removal.

The technical scheme adopted by the invention for realizing the purpose is as follows: a high-efficiency sponge iron desulfurizer comprises the following components by weight: sponge iron: 40% -50%; wood chip: 14% -20%; slaking lime: 1% -10%; gypsum: 30 to 40 percent.

The invention has the beneficial effects that:

(1) the components are stable. The invention produces the sponge iron total iron with micropores by using the south African ore or the Brazilian pellet as the raw material, and the sponge iron has higher and stable content and less impurity content. The invention utilizes the characteristic that sponge iron has micropores to increase the contact surface with hydrogen sulfide, utilizes the characteristic that sponge iron contains stable iron components, has the total iron content of 91-94 percent and has high iron content to increase the stability of desulfurization efficiency, and is a new application in industry. Therefore, the desulfurizer prepared by using the sponge iron as the base material has extremely stable components and good desulfurization effect, and the average desulfurization efficiency reaches more than 95 percent.

(2) The service life is long. Because the sponge iron particles have a plurality of micropores, the porosity of the sponge iron high-efficiency desulfurizer is high, the reaction contact area with hydrogen sulfide gas is large, and the micropores can absorb more sulfur, so that the sulfur capacity is more than 40 percent, and the service cycle is long.

(3) The regeneration effect is good. The sponge iron high-efficiency desulfurizer can adopt intermittent regeneration and continuous regeneration, so that the desulfurizer with saturated sulfur capacity recovers the desulfurization capability. The intermittent regeneration process is as follows: firstly cutting off raw material gas, when the pressure in the tower is reduced to the pressure of a downstream system, closing an outlet valve to isolate a regeneration tower from a production system, then opening a top bleeding valve to release pressure, when the pressure in the tower is reduced to be balanced with the external pressure, introducing steam to replace coal gas, opening a bottom blowoff valve to allow air to enter a desulfurization tower, and introducing oxygen and Fe in the air₂S₃·H₂O reacts to make Fe₂S₃·H₂O is gradually changed into Fe₂O₃·H₂And O. The temperature in the tower should be controlled not to be higher than 65 ℃ in the regeneration process. The opening time of the blowoff valve is at least more than two days to meet the regeneration requirement, and the blowoff valve can be put into use again after the regeneration is finished. The continuous regeneration process is as follows: in the process of gas production, quantitative air (according to CO and H in the gas) is introduced into a gas pipeline entering a desulfurizing tower₂Content determined), and detecting the contents of oxygen and carbon monoxide in the coal gas on line, so that the desulfurizer is regenerated simultaneously in the desulfurization process.

Drawings

FIG. 1 is a flow chart of a manufacturing process of the present invention;

FIG. 2 is a schematic diagram of an apparatus according to an embodiment of the present invention;

Detailed Description

Embodiments of the invention are described in further detail below with reference to the following figures:

the invention relates to a sponge iron high-efficiency desulfurizer which comprises the following components in percentage by weight: sponge iron: 40% -50%; wood chip: 14% -20%; slaking lime: 1% -10%; gypsum: 30 to 40 percent.

The sponge iron of the invention is a raw material used for steel making. The coal-based direct reduction rotary kiln is produced by using a David direct reduction method (DRC method for short) introduced from David (DAVY) of England and related key equipment through the coal-based direct reduction rotary kiln. Adding south Africa lump ore or Brazil pellet ore, lignite and a small amount of limestone into a rotary kiln, and reducing iron oxide in the ore or pellet ore into metallic iron to form microporous massive iron or pellet ore, which is commonly called sponge iron.

The preparation process of the invention is shown in the attached figure 1, and comprises the following steps:

1. crushing and oxidizing: crushing sponge iron by a crusher, humidifying the crushed sponge iron, and then naturally oxidizing the crushed sponge iron in the air until the content of metallic iron is less than 1%;

2. screening: screening the oxidized sponge iron, reoxidizing undersize, crushing oversize, and circulating in such a way to form a sponge iron base material with high ferric oxide content; through the sieving and crushing circulation, the particle size of the sponge iron reaches about 0.5mm, so that the sponge iron is beneficial to extrusion forming during the production of the desulfurizer;

3. and (3) dry stirring: stirring uniformly by a disc stirrer to prepare a sponge iron base material;

4. mixing, humidifying and stirring: adding slaked lime, gypsum and wood dust into the prepared sponge iron base material, mixing, humidifying and uniformly stirring;

5. extrusion molding: the uniformly stirred mixture is input into a strip extruding machine for extrusion forming and agglomeration;

6. and (3) hot drying: drying the extruded blocks in an oven to obtain the sponge iron high-efficiency desulfurizer;

7. bagging: bagging for later use.

The desulfurization principle of the sponge iron high-efficiency desulfurizer of the invention is as follows: oxidizing sponge iron at 20-50 ℃, and gas H in the production process of coal gas and other chemical products₂S reacts, because the sponge iron contains stable Fe except the content₂O₃·H₂The O component has a characteristic of a large amount of micropores, and the reaction contact area and H can be increased₂The chemical reaction equation of the S adsorption quantity is as follows:

in the presence of oxygen, Fe₂S₃·H₂O is very unstable, Fe₂S₃·H₂O reacts with oxygen to regenerate the desulfurizing agent.

The sawdust of the invention is purchased from a wood processing factory;

the slaked lime of the invention is purchased from steel mills;

the gypsum of the invention is CaSO which is a mixed type purchased from chemical stores₄·1/2H₂O

Examples of the invention are illustrated below:

example 1:

a high-efficiency sponge iron desulfurizer comprises the following components by weight: according to the weight percentage, 40 percent of sponge iron, 15 percent of sawdust, 10 percent of slaked lime and 35 percent of gypsum are taken.

The preparation process of the embodiment of the invention is the same as the above process, and the description is omitted here. Finally, extruding the mixture into strips with the size of phi 7 multiplied by 50mm by an extruder, and drying the strips by a drying oven to obtain the finished product desulfurizer.

The apparatus for use of the invention is described below with reference to figure 2: the prepared desulfurizer is loaded into a simulated desulfurizing tower with the same structure as a dry desulfurizing tower of a gas plant, a gas outlet pipeline 11 of the simulated desulfurizing tower is connected with a bleeding valve 15 of a gas main pipeline of the dry desulfurizing tower, sampling ports 13 and 14 are respectively arranged on gas inlet and outlet pipelines 12 and 11 of the simulated desulfurizing tower, and a bleeding port 2 is arranged at the top; the upper part of the desulfurizing tower is provided with a coal gas outlet pressure measuring valve 1, and the lower part of the desulfurizing tower is provided with water drain valves 5 and 6 and a coal gas inlet pressure measuring valve 7;the upper part of the desulfurizing tower is also provided with a tower plate support 10.

The operation process and the detection result are explained as follows: in the desulfurizing tower, a coal gas inlet valve 4 and a coal gas outlet valve 3 are opened, coal gas is introduced, and the flow rate of the coal gas is 3.0-3.6 standard cubic meters (Nm) per hour³The temperature is 20-50 ℃, and the inlet pressure is 1000-4000 mm water column (mmH)₂O), outlet pressure 1000-3000 mm water column (mmH)₂O). The operation period is 90 days, and the average desulfurization efficiency is 95.72 percent.

Example 2:

a high-efficiency sponge iron desulfurizer comprises the following components by weight: according to the weight percentage, 50 percent of sponge iron, 14 percent of sawdust, 6 percent of slaked lime and 30 percent of gypsum are taken.

The preparation process for preparing the embodiment of the invention is the same as the above process, and the description is omitted here. Finally, extruding the mixture into strips with the size of phi 7 multiplied by 50mm by an extruder, and drying the strips by a drying oven to obtain the finished product desulfurizer.

The apparatus used in embodiment 2 of the present invention is the same as in embodiment 1, and therefore, the description thereof is omitted.

The operation process and the detection result are explained as follows: the prepared desulfurizer is loaded into a desulfurizing tower shown in figure 2, a gas inlet valve 4 and a gas outlet valve 3 are opened, gas is introduced, and the gas flow is 3.0 to 3.6 standard cubic meters (Nm) per hour³The temperature is 20-50 ℃, and the inlet pressure is 1000-4000 mm water column (mmH)₂O), outlet pressure 1000-3000 mm water column (mmH)₂O). The operation period is 90 days, and the average desulfurization efficiency is 95.90 percent.

Example 3:

a high-efficiency sponge iron desulfurizer comprises the following components by weight: according to the weight percentage, 45 percent of sponge iron, 14 percent of sawdust, 11 percent of slaked lime and 30 percent of gypsum are taken.

The apparatus used in embodiment 3 of the present invention is the same as in embodiment 1, and therefore, the description thereof is omitted.

The operation process and the detection result are explained as follows: the prepared desulfurizer is loaded into a desulfurizing tower shown in figure 2, a gas inlet valve 4 and a gas outlet valve 3 are opened, gas is introduced, and the gas flow is 3.0 to 3.6 standard cubic meters (Nm) per hour³The temperature is 20-50 ℃, and the inlet pressure is 1000-4000 mm water column (mmH)₂O), outlet pressure 1000-3000 mm water column (mmH)₂O). The operation period is 90 days, and the average desulfurization efficiency is 96.54 percent.

Claims

1. A high-efficiency sponge iron desulfurizer comprises the following components by weight: sponge iron: 40% -50%; wood chip: 14% -20%; slaking lime: 1% -10%; gypsum: 30 to 40 percent.

2. The desulfurizing agent according to claim 1, wherein the optimum ratio of the components and contents is: 45% of sponge iron, 14% of wood chips, 11% of slaked lime and gypsum: 30 percent.