A high-temperature coal gas purification system capable of utilizing waste heat and a method of using the system

Abstract

The invention discloses a high-temperature coal gas purification system capable of utilizing waste heat and a method for using the system, comprising a cooler, a pre-dust removal device, a ceramic fiber dust collector, and a fan, wherein the cooler is connected to the pre-dust removal device, the pre-dust removal device is connected to a recovery pipeline, the recovery pipeline is connected to the ceramic fiber dust collector through an inlet pipe and an outlet pipe, the fan is arranged on the recovery pipeline, and the recovery pipeline is connected to a venting pipe and a heat recovery pipe through the fan; a first pneumatic valve is arranged on the recovery pipeline, a second pneumatic valve is arranged on the venting pipe, a third pneumatic valve is arranged on the heat recovery pipe, a fourth pneumatic valve is arranged on the inlet pipe, and a fifth pneumatic valve is arranged on the outlet pipe; the invention arranges a high-temperature resistant ceramic fiber dust collector, so that the temperature of the purified flue gas is maintained at 400°C, and the temperature is always maintained above the dew point before reaching the drying furnace through the heat recovery pipe, thereby avoiding corrosion of the flue gas pipeline; at the same time, compared with a bag dust collector, when the flue gas 200°C higher is directly burned, this part of the high-temperature heat energy can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal gas purification devices, and in particular to a coal gas high-temperature purification system capable of utilizing waste heat and a use method thereof. Background Art

[0002] The production of ferronickel mainly uses nickel ore to be smelted by pyrometallurgy, and metallic nickel is obtained through reduction, melting and refining under high temperature conditions. During the smelting process of ferronickel, the smelting furnace will produce high-temperature flue gas of 600℃ to 1000℃. The flue gas contains a large amount of reusable coal gas and a large amount of suspended particles. If it is directly discharged into the environment without treatment, it will cause environmental pollution. The existing flue gas treatment technology is mainly bag dust removal technology. Since the filter bag is not resistant to high temperature, the conventional bag dust collector must cool the flue gas to below 260℃ for treatment.

[0003] The use of cooling equipment increases equipment investment and floor space. At the same time, the filter bag of the bag filter has poor filtering accuracy for pollutants with smaller diameters, which can easily cause flue gas emissions to fail to meet standards or filter bag clogging. At the same time, the filter bag is not resistant to high temperature shock and needs to be replaced frequently, resulting in high maintenance costs. The tail gas of the nickel-iron electric furnace is currently mainly reused as a heat source for the drying furnace and rotary kiln. The cooling treatment of the bag filter directly loses a large part of the heat energy. At the same time, the flue gas after cooling, due to the general distance between the dust collector and the drying furnace, when the flue gas is transported to the drying furnace, the temperature drops below 100°C, and the corrosive components in the flue gas are below the acid dew point, which will cause serious corrosion of the flue gas pipeline.

[0004] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention

[0005] In order to solve the above-mentioned technical defects, the technical solution adopted by the present invention is to provide a high-temperature gas purification system that can utilize waste heat, including a cooler, a pre-dust removal device, a ceramic fiber dust collector, and a fan. The cooler is connected to the pre-dust removal device, the pre-dust removal device is connected to a recovery pipeline, the recovery pipeline is connected to the ceramic fiber dust collector through an inlet pipe and an outlet pipe, the fan is arranged on the recovery pipeline, and the recovery pipeline is connected to a vent pipe and a heat recovery pipe through the fan; a first pneumatic valve is arranged on the recovery pipeline, a second pneumatic valve is arranged on the vent pipe, a third pneumatic valve is arranged on the heat recovery pipe, a fourth pneumatic valve is arranged on the inlet pipe, and a fifth pneumatic valve is arranged on the outlet pipe.

[0006] Preferably, the ceramic fiber dust collector is provided with a flower plate and a plurality of ceramic fiber filter tubes, the ceramic fiber filter tubes are fixedly arranged on the flower plate, the ceramic fiber dust collector is divided into an upper cavity and a lower cavity by the flower plate, the inlet pipe is connected to the lower cavity, the exhaust pipe is connected to the upper cavity, and the exhaust pipe is connected to the recovery pipeline.

[0007] Preferably, the ceramic fiber dust collector is also provided with a cleaning component, which includes a pulse valve, a nitrogen pulse blowing pipeline, and a nitrogen purge pipeline. Gas is supplied to the nitrogen pulse blowing pipeline and the nitrogen purge pipeline respectively through the pulse valve. The nitrogen pulse blowing pipeline is arranged above the flower plate in the ceramic fiber dust collector and corresponds to the upper port of the ceramic fiber filter tube; the nitrogen purge pipeline is arranged below the flower plate in the ceramic fiber dust collector.

[0008] Preferably, the cleaning component is further provided with a heater, and the nitrogen entering the nitrogen pulse injection pipeline and the nitrogen purge pipeline is heated by the heater.

[0009] Preferably, the cooler, the pre-dust removal device, and the lower outlet of the ceramic fiber dust collector are all provided with ash cleaning valves, and are connected to the ash conveying device through the ash cleaning valves, and the ash conveying device is connected to the ash bin.

[0010] Preferably, the ceramic fiber dust collector is provided in plurality and the plurality of the ceramic fiber dust collectors are connected in parallel, and the inlet pipe and the outlet pipe of each ceramic fiber dust collector are respectively provided with the fourth pneumatic valve and the fifth pneumatic valve.

[0011] Preferably, the inlet pipe is provided with an inlet temperature detector, and the outlet pipe is provided with an outlet temperature detector.

[0012] Preferably, a flue temperature sensor and a flue component detector are provided at the fan position.

[0013] Preferably, the material of the ceramic fiber filter tube is one of aluminum silicate fiber, aluminum oxide fiber and zirconium oxide fiber.

[0014] Preferably, the pore size of the filter layer of the ceramic fiber filter tube is 5 μm to 20 μm.

[0015] Preferably, the method for using the waste heat-utilizing high-temperature coal gas purification system comprises the following steps:

[0016] S1, connect the flue gas with the cooler, open the first pneumatic valve and the second pneumatic valve, close the third pneumatic valve, the fourth pneumatic valve and the fifth pneumatic valve, connect the pre-dust removal device with the emission pipe, and monitor the temperature and composition of the flue gas in real time through the flue temperature sensor and the flue component detector;

[0017] S2, closing the first pneumatic valve and the second pneumatic valve, and opening the third pneumatic valve, the fourth pneumatic valve, and the fifth pneumatic valve, so that the pre-dust removal device is connected to the heat recovery pipe through the ceramic fiber dust collector;

[0018] S3, detecting the temperature difference between the inlet and outlet of the ceramic fiber dust collector in real time through the outlet temperature detector and the inlet temperature detector, and controlling the gas flow rate restricted by the fourth pneumatic valve through the temperature difference until the ceramic fiber dust collector is in normal working condition.

[0019] Preferably, the calculation formula of the gas flow rate A limited by the fourth pneumatic valve is:

[0020]

[0021] Wherein, A is the gas flow rate limited by the fourth pneumatic valve; a is the initial gas flow rate limited by the fourth pneumatic valve; T1 is the detection temperature of the inlet temperature detector; T2 is the detection temperature of the outlet temperature detector; T Δ To allow a limited temperature difference.

[0022] Preferably, the inlet temperature detector detects that the flue gas temperature is 400°C to 450°C.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention maintains the temperature of the purified flue gas at 400°C by setting a high-temperature resistant ceramic fiber dust collector, and the temperature is always kept above the dew point before reaching the drying furnace through the heat recovery pipe, thereby avoiding corrosion of the flue gas pipeline; at the same time, compared with the bag dust collector, when the flue gas 200°C higher is directly burned, this part of the high-temperature heat energy can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a structural view of the high-temperature coal gas purification system that can utilize waste heat.

[0025] The numbers in the figure represent:

[0026] 1-Cooler; 2-Pre-dust removal device; 3-First ceramic fiber dust collector; 4-Second ceramic fiber dust collector; 5-Pulse valve; 6-Pneumatic valve; 7-Third ceramic fiber dust collector; 8-Heater; 9-Blower; 10-Nitrogen pulse injection pipeline; 11-Nitrogen purge pipeline; 12-Ash cleaning valve; 13-Ash conveying device; 14-Ash bin; 61-First pneumatic valve; 62-Second pneumatic valve; 63-Third pneumatic valve; 64-Fourth pneumatic valve; 65-Fifth pneumatic valve. DETAILED DESCRIPTION

[0027] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0028] Embodiment 1

[0029] like Figure 1 As shown, Figure 1 This is a structural view of the high-temperature gas purification system that can utilize waste heat; the high-temperature gas purification system that can utilize waste heat described in the present invention includes a cooler 1, a pre-dust removal device 2, a ceramic fiber dust collector, a pneumatic valve 6, a fan 9, a cleaning valve 12, an ash conveying device 13, and an ash bin 14.

[0030] The cooler 1 is connected to the pre-dust removal device 2, the pre-dust removal device 2 is connected to the recovery pipeline, the recovery pipeline is connected to the ceramic fiber dust collector through the inlet pipe and the outlet pipe, the fan 9 is arranged on the recovery pipeline, and the recovery pipeline is connected to the venting pipe and the heat recovery pipe through the fan 9. Preferably, the inlet pipe, the outlet pipe, the venting pipe and the heat recovery pipe are all provided with the pneumatic valve 6, and the pneumatic valve 6 is used to control the opening and closing of each pipeline.

[0031] Specifically, the recovery pipeline is provided with a first pneumatic valve 61, the vent pipe is provided with a second pneumatic valve 62, the heat recovery pipe is provided with a third pneumatic valve 63, the inlet pipe is provided with a fourth pneumatic valve 64, and the outlet pipe is provided with a fifth pneumatic valve 65.

[0032] The ceramic fiber dust collector is provided with a flower plate and a plurality of ceramic fiber filter tubes, the ceramic fiber filter tubes are fixedly arranged on the flower plate, an upper cavity and a lower cavity are formed in the ceramic fiber dust collector through the flower plate, the inlet pipe is connected to the lower cavity, the outlet pipe is connected to the upper cavity, and the outlet pipe is connected to the recovery pipeline.

[0033] The ceramic fiber dust collector is also provided with a cleaning component, which includes a pulse valve 5, a nitrogen pulse blowing pipeline 10, and a nitrogen purge pipeline 11. The pulse valve 5 is used to supply pulse gas to the nitrogen pulse blowing pipeline 10 and the nitrogen purge pipeline 11, thereby realizing backblowing dust removal of the ceramic fiber filter tube in the ceramic fiber dust collector.

[0034] Preferably, the cleaning component is also provided with a heater 8, by which the nitrogen entering the nitrogen pulse injection pipeline 10 and the nitrogen purge pipeline 11 is heated and heated before entering the injection cleaning, thereby avoiding thermal shock to the ceramic fiber dust collector filter tube caused by rapid temperature rise and fall.

[0035] Specifically, the nitrogen pulse blowing pipeline 10 is arranged above the inner flower plate of the ceramic fiber dust collector and corresponds to the upper port of the ceramic fiber filter tube, and the dust filtered on the outer surface of the ceramic fiber filter tube is cleaned by pulse blowing; the nitrogen purge pipeline 11 is arranged below the inner flower plate of the ceramic fiber dust collector, and when the nickel-iron smelting electric furnace gas high-temperature purification system that can utilize waste heat is stopped, the dust on the surface of the ceramic fiber filter tube below the flower plate is purged to prevent the dust from absorbing moisture and agglomerating on the surface of the filter tube to block the filter surface when the system is stopped.

[0036] The cooler 1, the pre-dust removal device 2, and the lower outlet of the ceramic fiber dust collector are all provided with the cleaning valve 12, and are connected to the ash conveying device 13 through the cleaning valve 12, and the ash conveying device 13 is connected to the ash bin 14. When the system is working, dust is generated, which passes through the cleaning valve 12, enters the ash conveying device 13, and then enters the ash bin 14. The ash conveying device 13 is a spiral ash conveying device, and all cleaning mechanisms are provided with nitrogen protection devices.

[0037] The ceramic fiber dust collectors are provided in three numbers, specifically including a first ceramic fiber dust collector 3, a second ceramic fiber dust collector 4, and a third ceramic fiber dust collector 7. Through the three-parallel structure of the ceramic fiber dust collectors, each of the inlet and outlet of the ceramic fiber dust collectors is equipped with a pneumatic valve. When the dust collectors are working, two of the ceramic fiber dust collectors filter, and one of the ceramic fiber dust collectors back-blows and cleans, and filtering and cleaning are performed alternately. The system adopts a PLC system, and the operation is stable and reliable.

[0038] The cooler 1 adopts air cooling or water cooling, and the cooler 1 is interlocked with the inlet temperature before the ceramic fiber dust collector to ensure that the inlet temperature is stable at 400℃~450℃; preferably, the inlet pipe and the outlet pipe are respectively provided with an inlet temperature detector and an outlet temperature detector, and the inlet temperature detector is used to detect the temperature of the flue gas before entering the ceramic fiber dust collector to ensure that the temperature is stable at 400℃~450℃, and the outlet temperature detector is used to detect the temperature of the flue gas after dust removal by the ceramic fiber dust collector, and is used to control the flow rate of the fourth pneumatic valve 64.

[0039] The pre-dust removal device 2 adopts a high-efficiency cyclone dust collector to remove large-particle dust in the flue gas, thereby reducing the load on the subsequent ceramic fiber dust collector.

[0040] Generally, a flue temperature sensor and a flue component detector are provided at the position of the fan 9. The temperature sensor and the component detector can detect the composition and temperature of the flue gas at the position of the fan 9, so as to facilitate the control of the flue gas circulation state.

[0041] The ceramic fiber dust collector adopts a high-temperature resistant ceramic fiber filter tube. The material of the ceramic fiber filter tube is a combination of aluminum silicate fiber, aluminum oxide fiber, zirconium oxide fiber, silica sol, aluminum sol, and zirconium sol. It can withstand high temperatures of 900°C to 1200°C. The ceramic fiber filter tube has a high porosity, a filter layer pore size of 5μm to 20μm, a small air resistance, and a high filtration accuracy.

[0042] The temperature of flue gas after purification by the ceramic fiber dust collector is about 400°C. Before it reaches the drying furnace through the heat recovery pipe, the temperature is always kept above the dew point, thus avoiding the corrosion of the flue gas pipeline. At the same time, compared with the bag type dust collector, when the flue gas with a temperature higher than 200°C is directly burned, this part of the high temperature heat energy can be saved.

[0043] Embodiment 2

[0044] The method for using the high-temperature purification system for electric furnace gas for ferronickel smelting of the present invention comprises the following steps:

[0045] S1, connect the flue gas with the cooler 1, open the first pneumatic valve 61 and the second pneumatic valve 62, close the third pneumatic valve 63, the fourth pneumatic valve 64 and the fifth pneumatic valve 65, connect the pre-dust removal device 2 with the emission pipe, and monitor the temperature and composition of the flue gas in real time through the flue temperature sensor and the flue component detector;

[0046] S2, close the first pneumatic valve 61 and the second pneumatic valve 62, open the third pneumatic valve 63, the fourth pneumatic valve 64, and the fifth pneumatic valve 65, so that the pre-dust removal device 2 is connected to the heat recovery pipe through the ceramic fiber dust collector;

[0047] S3, detecting the temperature difference between the inlet and outlet of the ceramic fiber dust collector in real time through the outlet temperature detector and the inlet temperature detector, and controlling the gas flow rate restricted by the fourth pneumatic valve 64 through the temperature difference until the ceramic fiber dust collector is in normal working condition.

[0048] In step S1, the exhaust temperature and exhaust volume of the nickel-iron smelting electric furnace flue gas are unstable at the beginning of the operation of the electric furnace. The initial flue gas is not suitable for entering the ceramic fiber dust collector. The flue gas goes directly to the chimney from the recovery pipeline and is ignited and then released.

[0049] In step S3, in order to protect the thermal shock of the ceramic fiber dust collector filter tube caused by the rapid rise and fall of the flue gas temperature, the ceramic fiber dust collector needs to slowly open the fourth pneumatic valve 64 to perform the intake air heating procedure when the flue gas enters. When the temperature inside the ceramic fiber dust collector reaches 400°C to 450°C, it can start normal working state.

[0050] Generally, during the intake air temperature rising procedure, the fourth pneumatic valve 64 limits the gas flow rate entering the ceramic fiber dust collector. Specifically, the calculation formula of the gas flow rate A limited by the fourth pneumatic valve 64 is:

[0051]

[0052] Wherein, A is the gas flow rate limited by the fourth pneumatic valve; a is the initial gas flow rate limited by the fourth pneumatic valve; T1 is the detection temperature of the inlet temperature detector; T2 is the detection temperature of the outlet temperature detector; T Δ To allow a limited temperature difference.

[0053] The initial gas flow rate a is the gas flow rate limited by the fourth pneumatic valve when ventilation is just started, which is generally set to half of the gas flow rate of the fourth pneumatic valve when the ceramic fiber dust collector is in normal working state; the allowable temperature difference T Δ It is generally set to 50°C, which means that when the temperature difference is within the range of 0°C to 50°C, the ceramic fiber dust collector is in normal working condition.

[0054] According to the above calculation formula, in the initial state, the gas flow A limited by the fourth pneumatic valve 64 is a. As the temperature difference between the detection temperature of the inlet temperature detector and the detection temperature of the outlet temperature detector continues to decrease, the gas flow limited by the fourth pneumatic valve gradually increases. When it reaches a reasonable range, the fourth pneumatic valve reaches the gas flow state during normal operation.

[0055] Generally, the flue gas is introduced into the ceramic fiber dust collector only when the inlet temperature detector detects that the flue gas temperature is 400°C to 450°C.

[0056] It is worth pointing out that since the ceramic fiber dust collector performs alternating cleaning work, the gas flow restricted by the fourth pneumatic valve 64 is controlled by the above formula, thereby ensuring that the ceramic fiber dust collector is always in a relatively stable temperature environment through airflow adjustment before and after the working state is switched.

[0057] The present invention can control the inlet and outlet gas temperatures of the ceramic fiber dust collector through temperature detection by the outlet temperature detector and the inlet temperature detector, and the coordinated cooperation of the fourth pneumatic valve 64 and the fifth pneumatic valve 65. While ensuring that the flue gas after dust removal has a high utilization temperature, it avoids the ceramic fiber dust collector from being in an environment with a large temperature change, thereby improving the service life of the ceramic fiber dust collector to a certain extent.

[0058] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A method for using a high-temperature gas purification system that can utilize waste heat, characterized in that: It includes a cooler, a pre-dust removal device, a ceramic fiber dust collector, and a fan, wherein the cooler is connected to the pre-dust removal device, the pre-dust removal device is connected to a recovery pipeline, the recovery pipeline is connected to the ceramic fiber dust collector through an inlet pipe and an outlet pipe, the fan is arranged on the recovery pipeline, and the recovery pipeline is connected to a venting pipe and a heat recovery pipe through the fan; a first pneumatic valve is arranged on the recovery pipeline, a second pneumatic valve is arranged on the venting pipe, a third pneumatic valve is arranged on the heat recovery pipe, a fourth pneumatic valve is arranged on the inlet pipe, and a fifth pneumatic valve is arranged on the outlet pipe; The inlet pipe is provided with an inlet temperature detector, and the outlet pipe is provided with an outlet temperature detector. A flue temperature sensor and a flue component detector are provided at the fan position; The following steps are involved: S1, connect the coal gas with the cooler, open the first pneumatic valve and the second pneumatic valve, close the third pneumatic valve, the fourth pneumatic valve and the fifth pneumatic valve, connect the pre-dust removal device with the emission pipe, and monitor the temperature and composition of the coal gas in real time through the flue temperature sensor and the flue component detector; S2, closing the first pneumatic valve and the second pneumatic valve, and opening the third pneumatic valve, the fourth pneumatic valve, and the fifth pneumatic valve, so that the pre-dust removal device is connected to the heat recovery pipe through the ceramic fiber dust collector; S3, detecting the temperature difference between the inlet and outlet of the ceramic fiber dust collector in real time by the outlet temperature detector and the inlet temperature detector, and controlling the gas flow rate limited by the fourth pneumatic valve by the temperature difference until the ceramic fiber dust collector is in a normal working state; The calculation formula of the gas flow rate A limited by the fourth pneumatic valve is: ; Wherein, A is the gas flow rate limited by the fourth pneumatic valve; a is the initial gas flow rate limited by the fourth pneumatic valve; T1 is the detection temperature of the inlet temperature detector; T2 is the detection temperature of the outlet temperature detector; T Δ To allow a limited temperature difference.

2. The method for using the high-temperature gas purification system capable of utilizing waste heat according to claim 1, characterized in that: The ceramic fiber dust collector is provided with a flower plate and a plurality of ceramic fiber filter tubes, the ceramic fiber filter tubes are fixedly arranged on the flower plate, the ceramic fiber dust collector is divided into an upper cavity and a lower cavity by the flower plate, the inlet pipe is connected to the lower cavity, the outlet pipe is connected to the upper cavity, and the outlet pipe is connected to the recovery pipeline.

3. The method for using the high-temperature gas purification system capable of utilizing waste heat according to claim 2, characterized in that: The ceramic fiber dust collector is also provided with a cleaning component, which includes a pulse valve, a nitrogen pulse blowing pipeline, and a nitrogen purge pipeline. Gas is supplied to the nitrogen pulse blowing pipeline and the nitrogen purge pipeline respectively through the pulse valve. The nitrogen pulse blowing pipeline is arranged above the flower plate in the ceramic fiber dust collector and corresponds to the upper port of the ceramic fiber filter tube; the nitrogen purge pipeline is arranged below the flower plate in the ceramic fiber dust collector.

4. The method for using the high-temperature gas purification system capable of utilizing waste heat as claimed in claim 3, characterized in that: The cleaning component is also provided with a heater, through which the nitrogen entering the nitrogen pulse injection pipeline and the nitrogen purge pipeline is heated.

5. The method for using the high-temperature gas purification system capable of utilizing waste heat according to claim 1, characterized in that: The cooler, the pre-dust removal device, and the lower outlets of the ceramic fiber dust collector are all provided with ash cleaning valves, and are connected to the ash conveying device through the ash cleaning valves, and the ash conveying device is connected to the ash bin.

6. The method for using the high-temperature gas purification system capable of utilizing waste heat according to claim 1, characterized in that: The ceramic fiber dust collectors are arranged in plurality and connected in parallel, and the inlet pipe and the outlet pipe of each ceramic fiber dust collector are respectively provided with the fourth pneumatic valve and the fifth pneumatic valve.

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