阅读说明：本技术 一种煤气化合成气脱汞剂及其制备方法 (Coal gasification synthesis gas mercury removal agent and preparation method thereof ) 是由 王鹏杰 刘刚 任永强 徐越 罗丽珍 于 2020-03-31 设计创作，主要内容包括：本发明公开一种煤气化合成气脱汞剂的制备方法,包括以下步骤：(1)将硝酸锌和尿素分别溶于去离子水中；混合溶液中硝酸锌和尿素的摩尔浓度范围比为1:(1～10)；然后将多孔二氧化钛粉末加入；(2)将混合液进行水浴加热,硝酸锌和尿素在此条件下生成纳米氧化锌,并沉积在多孔二氧化钛粉末微孔道上；(3)真空过滤,将过滤得到的固体放置于烘箱中干燥,获得固体颗粒；(4)将单质硫和步骤(3)制得的固体颗粒按(0.01～0.3):1的质量比进行混合研磨,然后焙烧制得煤气化合成气脱汞剂。本发明制备的脱汞剂一方面实现了合成气还原性气氛下单质汞的直接脱除,另一方面脱汞剂还可以在中温条件下(150-300℃)使用,避免了系统由于反复升温降温导致的能量损失。(The invention discloses a preparation method of a coal gasification synthesis gas mercury removal agent, which comprises the following steps: (1) respectively dissolving zinc nitrate and urea in deionized water; the molar concentration range ratio of the zinc nitrate to the urea in the mixed solution is 1 (1-10); then adding porous titanium dioxide powder; (2) heating the mixed solution in water bath, generating nano zinc oxide by the zinc nitrate and the urea under the condition, and depositing the nano zinc oxide on the porous titanium dioxide powder micro-channel; (3) vacuum filtering, and drying the solid obtained by filtering in an oven to obtain solid particles; (4) and (4) mixing and grinding the elemental sulfur and the solid particles prepared in the step (3) according to the mass ratio of (0.01-0.3) to 1, and then roasting to prepare the coal gasification synthesis gas mercury removal agent. The mercury removing agent prepared by the invention realizes the direct removal of elemental mercury in the reducing atmosphere of the synthesis gas, and can be used at a medium temperature (150 ℃ C. and 300 ℃ C.), thereby avoiding the energy loss of the system caused by repeated temperature rise and temperature drop.)

1. The preparation method of the coal gasification synthesis gas mercury removing agent is characterized by comprising the following steps:

(1) respectively dissolving zinc nitrate and urea in deionized water, and then mixing and uniformly stirring the two solutions to obtain a mixed solution; the molar concentration range ratio of the zinc nitrate to the urea in the mixed solution is 1 (1-10); then adding the porous titanium dioxide powder into the mixed solution to obtain a mixed solution; the mass of the porous titanium dioxide powder accounts for 5-80% of the mass of the mixed solution;

(2) heating the mixed solution in water bath, generating nano zinc oxide by the zinc nitrate and the urea under the condition, and depositing the nano zinc oxide on the porous titanium dioxide powder micro-channel;

(3) vacuum filtering the mixed solution reacted in the step (2), and repeatedly washing with deionized water until the filtrate is neutral; putting the solid obtained by filtering into an oven for drying to obtain solid particles;

(4) and (3) mixing and grinding the elemental sulfur and the solid particles prepared in the step (3) according to the mass ratio of (0.01-0.3) to 1, and then placing the mixture into a muffle furnace for roasting, wherein the roasting atmosphere is nitrogen, so as to prepare the coal gasification synthesis gas mercury removal agent.

2. The preparation method of the coal gasification synthesis gas mercury removing agent according to claim 1, wherein the particle size of the nano zinc oxide is 10-50 nm.

3. The preparation method of the coal gasification synthesis gas mercury removing agent according to claim 1, wherein the average particle size of the porous titanium dioxide powder is 300 microns, and the specific surface area is 100-300 m²/g。

4. The preparation method of the coal gasification synthesis gas mercury removing agent according to claim 1, wherein the solid obtained by filtering in the step (3) is dried in an oven at 120 ℃ for 2 to 4 hours to obtain solid particles.

5. The preparation method of the coal gasification synthesis gas mercury removing agent according to claim 1, wherein the roasting temperature in the step (4) is 250-600 ℃, and the roasting time is 2-4 hours.

6. The preparation method of the coal gasification synthesis gas mercury removing agent according to claim 1, wherein the water bath heating temperature in the step (2) is 70-100 ℃, and the water bath heating time is 2-4 hours.

7. The coal gasification synthesis gas mercury removal agent prepared by the preparation method of the coal gasification synthesis gas mercury removal agent according to any one of claims 1 to 6.

Technical Field

The invention belongs to the technical field of coal gasification, and particularly relates to a coal gasification synthesis gas mercury removal agent and a preparation method thereof.

Background

At present, the traditional coal utilization method has serious influence on the environment of China, and the clean utilization of coal is the key for the coordinated development of energy and environment. With the increasingly prominent energy and environmental problems, the demand for clean coal utilization technology is more and more urgent. The coal gasification technology converts coal into synthesis gas for utilization, has the characteristics of cleanness, high efficiency and low pollution, and is the most effective way for the clean and efficient utilization of the coal. At present, scholars at home and abroad mainly concentrate on the research on the emission and control of mercury in coal-fired flue gas, and the research on the mercury emission control in coal gasification is less. With the rapid development of coal gas-based high-efficiency coal utilization technology, the control of mercury in the coal gasification synthesis gas is especially important for controlling the emission of harmful trace element mercury.

The mercury released in the coal utilization process mainly exists in 3 forms, namely granular mercury (Hg)^p) Mercury (Hg) in its oxidized state²⁺) And elemental mercury (Hg)⁰). Granular mercury (Hg)^p) Can be removed by particulate control equipment to remove mercury (Hg) in oxidized form²⁺) By wet scrubbing or SO₂The control equipment is used for removing, and the elemental mercury is not easy to dissolve and is difficult to remove by using common dust removal equipment. The traditional coal utilization mode is a pulverized coal combustion process, the generated flue gas is an oxidizing atmosphere, elemental mercury in the flue gas can be oxidized into oxidized mercury and removed together by adopting a catalyst, the synthetic gas generated by coal gasification is a reducing atmosphere, and the elemental mercury in the synthetic gas cannot be removed in an oxidized mercury mode, so that the difficulty in removing mercury in coal gasification is higher compared with that of coal-fired flue gas.

Disclosure of Invention

The invention aims to provide a coal gasification synthesis gas mercury removal agent and a preparation method thereof, so as to solve the technical problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a coal gasification synthesis gas mercury removal agent comprises the following steps:

(1) respectively dissolving zinc nitrate and urea in deionized water, and then mixing and uniformly stirring the two solutions to obtain a mixed solution; the molar concentration range ratio of the zinc nitrate to the urea in the mixed solution is 1 (1-10); then adding the porous titanium dioxide powder into the mixed solution to obtain a mixed solution; the mass of the porous titanium dioxide powder accounts for 5-80% of the mass of the mixed solution;

(2) heating the mixed solution in water bath, generating nano zinc oxide by the zinc nitrate and the urea under the condition, and depositing the nano zinc oxide on the porous titanium dioxide powder micro-channel;

(3) vacuum filtering the mixed solution reacted in the step (2), and repeatedly washing with deionized water until the filtrate is neutral; putting the solid obtained by filtering into an oven for drying to obtain solid particles;

(4) and (3) mixing and grinding the elemental sulfur and the solid particles prepared in the step (3) according to the mass ratio of (0.01-0.3) to 1, and then placing the mixture into a muffle furnace for roasting, wherein the roasting atmosphere is nitrogen, so as to prepare the coal gasification synthesis gas mercury removal agent.

Furthermore, the particle size of the nano zinc oxide is 10-50 nanometers.

Furthermore, the average particle size of the porous titanium dioxide powder is 300 microns, and the specific surface area is 100-300 m²/g。

Further, in the step (3), the solid obtained by filtration is placed in an oven to be dried at 120 ℃ for 2 to 4 hours, and solid particles are obtained.

Further, in the step (4), the roasting temperature is 250-600 ℃, and the roasting time is 2-4 hours.

Further, the temperature of water bath heating in the step (2) is 70-100 ℃, and the time of water bath heating is 2-4 hours.

A coal gasification synthesis gas mercury removal agent prepared by a preparation method of the coal gasification synthesis gas mercury removal agent.

Compared with the prior art, the invention has the following beneficial effects:

the mercury removing agent for the coal gasification synthesis gas is prepared from nano zinc oxide, porous titanium dioxide and sulfur, and the mercury removing agent is prepared from zinc nitrate, urea, porous titanium dioxide powder and sulfur. The mercury removing agent prepared by the invention realizes the direct removal of elemental mercury in the reducing atmosphere of the synthesis gas, and can be used at a medium temperature (150 ℃ C. and 300 ℃ C.), thereby avoiding the energy loss of the system caused by repeated temperature rise and temperature drop.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart of the preparation of coal gasification synthesis gas mercury removing agent.

Detailed Description

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.