Low-temperature dry desulfurization method

Abstract

The application provides a low-temperature dry desulfurization method, comprising the following steps: injecting nitrogen into an activated carbon layer to perform activation treatment; passing waste gas to be desulfurized through the activated activated carbon layer to obtain preliminary desulfurized waste gas; passing the preliminary desulfurized waste gas through a dry adsorbent powder layer to obtain treated waste gas; in the step of injecting nitrogen into the activated carbon layer to perform activation treatment, the temperature of the injected nitrogen is 900-1100 DEG C, and the injection mode is intermittent injection. Different from a traditional low-temperature dry desulfurization mode, the activation process of activated carbon is combined with the low-temperature dry desulfurization method, the activated carbon is immediately put into the desulfurization process after modification, so that the activated carbon carries the waste heat of high-temperature nitrogen, and the waste heat of the high-temperature nitrogen is utilized for heating, thereby realizing full utilization of the waste heat in the activated carbon modification process, enabling the catalytic reaction in the low-temperature dry desulfurization process to be rapidly performed, and improving the treatment speed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of desulfurization, and particularly relates to a low-temperature dry desulfurization method. BACKGROUND

[0002] Desulfurization methods generally include pre-combustion, combustion and post-combustion desulfurization. With the development of industry and the improvement of people's living standards, the demand for energy is increasing, and SO2 in coal-fired flue gas has become the main cause of air pollution. Reducing SO2 pollution has become an urgent task in the current air environmental management. Many flue gas desulfurization processes have been widely used in industry, and they also have important practical significance for the treatment of tail gas of various boilers and incinerators.

[0003] In the existing low-temperature dry desulfurization process, activated carbon is usually used to carry V2O5 catalyst, so that the reaction temperature can be as low as 150 DEG C, thereby achieving the purpose of low-temperature dry desulfurization. However, the inventor found in the use of the above process that when using activated carbon to carry V2O5 catalyst, the conventional activated carbon has poor porosity and poor thermal stability, resulting in incomplete desulfurization in the waste gas treatment process in the low-temperature dry desulfurization process. In order to solve the above technical problems, the person skilled in the art reduces the flow rate of the waste gas to be introduced and increases the residence time of the waste gas on the activated carbon to ensure more complete desulfurization.

[0004] However, the above method results in slow overall treatment speed of the low-temperature dry desulfurization. SUMMARY

[0005] Therefore, the application provides a low-temperature dry desulfurization method to solve the technical problems of low efficiency and slow treatment speed of low-temperature dry desulfurization. In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not a general review, nor is it intended to determine key / important elements or delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0006] The application adopts the following technical solutions:

[0007] A low-temperature dry desulfurization method is provided, comprising the following steps:

[0008] Nitrogen is injected into the activated carbon layer for activation treatment;

[0009] The desulfurization waste gas to be treated is passed through the activated activated carbon layer to obtain preliminary desulfurization waste gas;

[0010] The preliminary desulfurization waste gas is passed through the dry adsorbent powder layer to obtain treated waste gas;

[0011] In the step of injecting nitrogen into the activated carbon layer and performing activation treatment, the temperature of the injected nitrogen is 900-1100 DEG C, and the injection mode is intermittent injection.

[0012] The activated carbon layer comprises an activated carbon carbon package and a net cage, the activated carbon carbon package is arranged in the net cage, and the activated carbon carbon package is provided with a waste gas inlet, a waste gas outlet and a nitrogen gas inlet.

[0013] The waste gas inlet and the nitrogen gas inlet are respectively provided with a one-way valve.

[0014] The waste gas outlet is provided with an electromagnetic valve.

[0015] The waste gas outlet extends into the dry adsorbent powder layer, the dry adsorbent powder layer is filled with adsorbent powder, and the adsorbent powder covers the waste gas outlet.

[0016] The dry adsorbent powder layer comprises an adsorbent tank, the bottom of the tank is arc-shaped, and the bottom is connected with the waste gas outlet; the adsorbent powder is filled in the adsorbent tank, and the filling amount is one third of the volume of the tank.

[0017] In the step of passing the desulfurization waste gas through the activated activated carbon layer to obtain the preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 200-900 DEG C.

[0018] In the step of passing the desulfurization waste gas through the activated activated carbon layer to obtain the preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 300-500 DEG C.

[0019] When the temperature in the activated activated carbon layer is less than 200 DEG C, the injection speed of the desulfurization waste gas is reduced.

[0020] The beneficial effects brought by the present application: different from the traditional low-temperature dry desulfurization method, the activation process of activated carbon is combined with the low-temperature dry desulfurization method, after the modification of activated carbon, it is immediately put into the desulfurization process, so that the activated carbon carries the waste heat of high-temperature nitrogen gas, and the waste heat of high-temperature nitrogen gas is utilized for heating, so as to realize the full utilization of waste heat in the modification process of activated carbon, so that the catalytic reaction in the low-temperature dry desulfurization process can be quickly carried out, and the processing speed is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is the flowchart of the present application;

[0022] Fig. 2 is the structure diagram of the activated carbon layer and the dry adsorbent powder layer of the present application. DETAILED DESCRIPTION

[0023] The following description and accompanying drawings fully illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Some portions and features of some embodiments may be included in or replace portions and features of other embodiments.

[0024] like Figs. 1-2 As shown in some illustrative embodiments, the present invention discloses a low-temperature dry desulfurization method, wherein the activated carbon layer used includes: activated carbon bag 1 and wire mesh cage 2; the activated carbon bag 1 is disposed in the wire mesh cage 2, the wire mesh cage 2 is used to fix the activated carbon bag 1, the activated carbon bag 2 can be replaced after use, the new activated carbon bag is installed in the wire mesh cage 2 for continued use, and the old activated carbon bag is recycled and disposed of, thereby shortening the downtime. The activated carbon bag 1 is provided with exhaust gas inlet 3, exhaust gas outlet 4 and nitrogen inlet 5.

[0025] The exhaust gas inlet 3 and nitrogen inlet 5 are each equipped with a one-way valve, so that the exhaust gas or nitrogen to be treated can only enter in one direction and will not rush out in the opposite direction.

[0026] The exhaust gas outlet 4 is equipped with an electromagnetic valve. The electromagnetic valve can control the pressure inside the activated carbon bag 1 and also control the exhaust gas to be treated inside the activated carbon bag 1 to be discharged into the dry adsorbent powder layer as required.

[0027] The solenoid valves and check valves mentioned above are very common valve structures in this field, so no specific designation or model number is specified here.

[0028] The exhaust gas outlet 4 extends into the dry adsorbent powder layer; the dry adsorbent powder layer is filled with adsorbent powder 7, and the adsorbent powder 7 covers the exhaust gas outlet 4, so that the exhaust gas can fully contact the adsorbent powder 7 when it is sprayed out.

[0029] The dry adsorbent powder layer includes: an adsorbent box 6 with an arc-shaped bottom, the bottom of which is connected to the exhaust gas outlet 4; adsorbent powder 7 is filled into the adsorbent box 6, filling one-third of the box's volume; exhaust gas, carrying initial temperature, is injected into the dry adsorbent powder layer through the exhaust gas outlet 4, and undergoes a desulfurization reaction through the mixing reaction of the adsorbent powder 7. This invention has no requirements on the particle size or composition of the dry adsorbent powder; any adsorbent powder from existing desulfurization processes can be used, and no limitation is made here. The main improvement of this invention lies in the overall desulfurization method.

[0030] The low-temperature dry desulfurization method of the present application comprises:

[0031] First, nitrogen is injected into the activated carbon layer for activation treatment. The temperature of the injected nitrogen is 900-1100℃, and the injection mode is intermittent injection. Intermittent injection means that nitrogen at 900℃ is first injected into the activated carbon layer, and then nitrogen at a temperature higher than 900℃ is injected again until the pressure in the activated carbon package 1 is 1.5 standard atmospheres, maintained for 2 hours, and the activation treatment is completed.

[0032] The desulfurization waste gas to be treated is passed through the activated activated carbon layer to obtain a preliminary desulfurization waste gas.

[0033] The preliminary desulfurization waste gas is passed through the dry adsorbent powder layer to obtain a treated waste gas.

[0034] In an alternative embodiment, in the step of passing the desulfurization waste gas to be treated through the activated activated carbon layer to obtain a preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 200-900℃.

[0035] In another alternative embodiment, in the step of passing the desulfurization waste gas to be treated through the activated activated carbon layer to obtain a preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 300-500℃.

[0036] More preferably, when the temperature in the activated activated carbon layer is less than 200℃, a too fast injection speed of the desulfurization waste gas to be treated will rapidly cause the temperature of the activated carbon layer less than 200℃ to drop rapidly, resulting in incomplete desulfurization, so the injection speed of the desulfurization waste gas to be treated is reduced to make the low-temperature dry desulfurization more complete.

[0037] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

Claims

1. A cryogenic dry desulfurization method, characterized by, It comprises the following steps: The activated carbon layer is first injected with nitrogen gas for activation treatment, the temperature of the nitrogen gas injection is 900-1100℃, and the injection mode is intermittent injection; the intermittent injection is that the activated carbon layer is first injected with nitrogen gas at 900℃, and then injected with nitrogen gas higher than 900℃, until the pressure in the activated carbon package is 1.5 standard atmospheres, and maintained for 2 hours, to complete the activation treatment; the desulfurization waste gas is passed through the activated activated carbon layer to obtain preliminary desulfurization waste gas; the preliminary desulfurization waste gas is passed through the dry adsorbent powder layer to obtain treated waste gas; after the modification of the activated carbon, it is immediately put into the desulfurization process, so that the activated carbon will carry the residual heat of high-temperature nitrogen gas, and utilize the residual heat of high-temperature nitrogen gas for heating; The activated carbon layer comprises: an activated carbon package and a mesh cage; the activated carbon package is arranged in the mesh cage, and the activated carbon package is provided with a waste gas inlet, a waste gas outlet and a nitrogen gas inlet; the waste gas inlet and the nitrogen gas inlet are respectively provided with a one-way valve; the waste gas outlet is provided with an electromagnetic valve; the waste gas outlet extends into the dry adsorbent powder layer; the dry adsorbent powder layer is filled with adsorbent powder, and the adsorbent powder covers the waste gas outlet; The dry adsorbent powder layer comprises: an adsorbent box, the bottom of the box is arc-shaped, and the bottom is connected with the waste gas outlet; the adsorbent powder is filled in the adsorbent box, and the filling amount is one-third of the volume of the adsorbent box.

2. A cryogenic dry desulfurization method according to claim 1, characterized in that, In the step of passing the desulfurization waste gas through the activated activated carbon layer to obtain preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 200-900℃.

3. A cryogenic dry desulfurization method according to claim 2, characterized in that, In the step of passing the desulfurization waste gas through the activated activated carbon layer to obtain preliminary desulfurization waste gas, the temperature in the activated activated carbon layer is 300-500℃.

4. A cryogenic dry desulfurization method according to claim 3, characterized in that, When the temperature in the activated activated carbon layer is less than 200℃, the injection speed of the desulfurization waste gas is reduced.

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