Electric heating low-rank coal low-temperature pyrolysis system

Abstract

The utility model provides an electric heating low-rank coal low-temperature pyrolysis system which comprises an electric heating furnace, a coal pyrolysis furnace and a coal gas cooling and purifying mechanism which are sequentially and circularly communicated, a stop valve is arranged on a pipeline between the electric heating furnace and the coal pyrolysis furnace, and a regulating valve is arranged on a pipeline between the coal gas cooling and purifying mechanism and the coal pyrolysis furnace. And the coal gas cooling and purifying mechanism is communicated with the output pipeline. The external electric heating furnace is adopted to heat circulating coal gas to serve as a heat carrier for raw coal pyrolysis in the vertical furnace, the heat source of the method is stable, the dry distillation temperature of raw coal is stable, air is not introduced in the pyrolysis process, the content of nitrogen and carbon dioxide in finished coal gas is reduced, the content of high-quality gas such as hydrogen, carbon monoxide and methane in the coal gas is increased, and the energy consumption is reduced. The calorific value and the quality of the coal gas are improved, and solid basic conditions are provided for subsequent chemical deep processing of the coal gas.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the coal chemical industry low temperature pyrolysis technical field, specifically relates to a kind of electric heating low-rank coal low temperature pyrolysis system. BACKGROUND

[0002] China is rich in low metamorphic coal resources, and the coal gas, semi coke and tar obtained by low temperature pyrolysis is an effective method for low metamorphic coal quality utilization. At present, the semi coke produced by low metamorphic coal mainly uses the internal combustion internal heating type vertical carbonization furnace pyrolysis process: the lump coal is added from the top of the furnace, and air is used as the oxygen source, and air and air are introduced into the lower part of the furnace to burn, and the high-temperature gas generated is opposite to the lump coal in the furnace to realize heat exchange and low temperature pyrolysis (the temperature is generally below 750℃), and the mixed gas after pyrolysis is discharged outside the furnace, and the coal tar and coal gas are recovered after washing and purification treatment.

[0003] Although the semi coke produced by this process is stable and reliable, it also brings some problems to the subsequent coal gas purification and comprehensive utilization. First, the combustion flue gas produced by the internal combustion internal heating heating method is mixed with the coal gas generated by the pyrolysis of raw coal, and the coal gas discharged from the furnace contains a large amount of nitrogen, which not only increases the treatment capacity of the coal gas purification system, but also reduces the calorific value of the coal gas, which greatly affects the subsequent high value-added processing and utilization of coal gas, and it is difficult to meet the requirements of industry or civil use; second, because there is a combustion reaction in the furnace, not only the semi coke is burned, but also the high temperature generated by the combustion affects the normal operation of the furnace. If the temperature is too high, it is easy to cause coking and blockage of the furnace, so that the vertical furnace cannot operate normally. When coking occurs, not only the treatment is difficult and the labor intensity is large, but also the loss caused by shutdown; if the temperature is too low, it may also cause incomplete dry distillation, which affects the product quality and yield of semi coke. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing an electric heating low-rank coal low temperature pyrolysis system to solve the above technical problems existing in the prior art.

[0005] Therefore, the utility model provides the technical scheme as follows:

[0006] An electric heating low-rank coal low temperature pyrolysis system, which comprises an electric heating furnace, a coal pyrolysis furnace and a coal gas cooling and purification mechanism connected in sequence, a cut-off valve is arranged on the pipeline between the electric heating furnace and the coal pyrolysis furnace, an adjusting valve is arranged on the pipeline between the coal gas cooling and purification mechanism and the coal pyrolysis furnace, and the coal gas cooling and purification mechanism is communicated with an external pipeline.

[0007] It also comprises an electric control cabinet and a flowmeter, the flowmeter is arranged on the pipeline between the coal gas cooling and purification mechanism and the coal pyrolysis furnace, and the flowmeter and the adjusting valve are electrically connected with the electric control cabinet.

[0008] The electric heating furnace is two, one is used, and the other is standby, and a circulating gas pipeline, a tee, a communication pipeline and a tapping pipeline are arranged between the coal gas cooling and purifying mechanism and the electric heating furnace.

[0009] The outlet of the coal gas cooling and purifying mechanism is communicated with the circulating gas pipeline, the circulating gas pipeline is communicated with the inlet of the tee, two outlets of the tee are communicated with a communication pipeline respectively, the outlet of the communication pipeline is communicated with the tapping pipeline, and the tapping pipeline is communicated with the electric heating furnace.

[0010] The nitrogen blowing system is further arranged, and the nitrogen blowing system is communicated with the lower part of the electric heating furnace through a pipeline provided with a blowing valve.

[0011] The adjusting valve is arranged on the tapping pipeline.

[0012] The heating rod of the electric heating furnace is a silicon carbide rod.

[0013] The cut-off valve is a water-cooled hot air cut-off valve.

[0014] The coal pyrolysis furnace comprises a top stock bin, a vertical furnace and a coke discharging device below the furnace, the top stock bin is arranged at the top of the vertical furnace, the lower part of the vertical furnace is connected with the coke discharging device below the furnace, and the dry distillation temperature range in the vertical furnace is 500-750 DEG C.

[0015] The temperature in the electric heating furnace is 800-1000 DEG C.

[0016] The beneficial effects of the present application are as follows:

[0017] The present application uses an external electric heating furnace to heat circulating coal gas as a heat carrier for pyrolysis of raw coal in a vertical furnace, uses electricity as an energy source for pyrolysis of coal, and has stable heat source and stable dry distillation temperature of raw coal, does not introduce air during pyrolysis, reduces the content of nitrogen and carbon dioxide in finished coal gas, improves the content of hydrogen, carbon monoxide, methane and other high-quality gases in coal gas, improves the calorific value and quality of coal gas, and provides a solid foundation for subsequent chemical deep processing of coal gas. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of one embodiment of the present application.

[0019] In the drawing: 1, electric heating furnace; 2, coal pyrolysis furnace; 3, coal gas cooling mechanism; 4, coal gas adjusting valve; 5, cut-off valve; 6, nitrogen blowing system; 7, blowing valve; 8, circulating gas pipeline; 9, communication pipeline; 10, tapping pipeline; 11, blowing pipeline. DETAILED DESCRIPTION

[0020] The following detailed description of the application will be made with reference to the accompanying drawings.

[0021] The present application is described herein with reference to the accompanying drawings, in which specific embodiments of the application are shown. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art. In the drawings, like reference numerals refer to like elements throughout.

[0022] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0023] Example 1

[0024] The present application provides a kind of electric heating low-rank coal low temperature pyrolysis system, as shown in Figure 1 The pipeline between the electric heating furnace 1 and the coal pyrolysis furnace 2 is provided with a cut-off valve 5, the pipeline between the gas cooling and purification mechanism 3 and the electric heating furnace 1 is provided with a regulating valve 4, and the gas cooling and purification mechanism 3 is communicated with the external pipeline.

[0025] Working principle:

[0026] The coal gas produced by the coal pyrolysis furnace 2 is purified and cooled by the gas cooling and purification mechanism 3, and part of the coal gas enters the electric heating furnace 1 as circulating gas, and the remaining coal gas is sent to the subsequent section for use. The amount of circulating gas entering the electric heating furnace 1 can be adjusted and controlled by the regulating valve 4, and the circulating gas as a heat carrier is heated to about 800 DEG C in the electric heating furnace 1 to provide sufficient and stable heat source for the dry distillation of the pyrolysis furnace.

[0027] The utility model discloses an external electric heating furnace 1, and the heat supply is controllable and adjustable, which can guarantee the stability of the heat supply of the vertical furnace (coal pyrolysis furnace 2), avoid the slagging in the furnace, and effectively improve the product quality.

[0028] Example 2

[0029] On the basis of example 1, the utility model provides a kind of electric heating low rank coal low temperature pyrolysis system, further including electric control cabinet and flowmeter, the flowmeter is located on the pipeline between coal gas cooling purification mechanism 3 and coal pyrolysis furnace 2, and the flowmeter, regulating valve 4 are all with electric control cabinet electric signal connection.

[0030] According to the pyrolysis temperature requirement, the amount of circulating coal gas is obtained by heat balance calculation and flow setting;Control cabinet real-time monitoring flow data of flowmeter, when flow data exceeds the set value allowable range, control cabinet sends signal to regulating valve 4 and adjusts.

[0031] Example 3

[0032] On the basis of example 1, the utility model provides a kind of electric heating low rank coal low temperature pyrolysis system, and the electric heating furnace 1 is two, one uses, and one is spare, and the coal gas cooling purification mechanism 3 and electric heating furnace 1 are equipped with circulating coal gas pipeline 8, three-way, communication pipeline 9 and tapping pipeline 10 communication;

[0033] The outlet of the coal gas cooling purification mechanism 3 and the circulating coal gas pipeline 8 are communicated, the circulating coal gas pipeline 8 and the inlet of the three-way are communicated, the two outlets of the three-way are communicated with a communication pipeline 9 respectively, the outlet of the communication pipeline 9 and the tapping pipeline 10 are communicated, the tapping pipeline 10 and the electric heating furnace 1 are communicated, and the regulating valve 4 is arranged on the tapping pipeline 10.

[0034] As shown in Figure 1 The electric heating furnace 1 in the embodiment adopts the configuration mode of one use and one spare, and two electric heating furnaces 1 are used in turn.When one of the furnaces runs for a period of time, the front regulating valve 4 of the electric heating furnace 1 and the rear cut-off valve 5 of the electric heating furnace 1 are closed, and a small amount of air is used to burn and remove the carbon deposited on the silicon-carbon rods in the electric heating furnace.

[0035] Example 4

[0036] Based on embodiment 3, the present embodiment provides an electric heating low-rank coal low-temperature pyrolysis system, further comprising a nitrogen purging system 6, which is in communication with the lower part of the electric heating furnace 1 through a pipeline, and a purging valve 7 is arranged on the pipeline.

[0037] As shown in the figure, the purging valve 7 is opened, and nitrogen is purged through the purging pipeline 11 to the electric heating furnace 1. Figure 1

[0038] Embodiment 5

[0039] Based on embodiment 1, the present embodiment provides an electric heating low-rank coal low-temperature pyrolysis system, wherein the heating rod of the electric heating furnace 1 is a silicon carbide rod.

[0040] The present embodiment uses a silicon carbide rod for heating, which can maintain good performance in a high-temperature environment, and can heat the coal gas to about 800℃ by using an electric energy source. In a high-temperature oxidation environment, the silicon carbide can form a layer of quartz glass film on the surface, which plays a role of isolation and protection, and has good oxidation resistance.

[0041] Embodiment 6

[0042] Based on embodiment 1, the present embodiment provides an electric heating low-rank coal low-temperature pyrolysis system, wherein the shut-off valve 5 is a water-cooled hot air shut-off valve.

[0043] The water-cooled hot air shut-off valve can cool the valve to avoid deformation of the valve cover caused by continuous high temperature, and leakage caused by poor sealing.

[0044] In the present embodiment, the coal pyrolysis furnace 2 comprises a top bin, a vertical furnace and a furnace under-coke discharge device, the top bin is arranged on the top of the vertical furnace and connected thereto, and the lower part of the vertical furnace is connected with the furnace under-coke discharge device.

[0045] The specification size of the vertical furnace is not limited, and corresponding semi-coke production of 100,000 tons / year, 150,000 tons / year, 200,000 tons / year and more can be used; the vertical furnace adopts an external heat source, full-chamber material and reverse direct heat exchange design. The lower part of the vertical furnace is provided with a hot circulating gas inlet; the dry distillation temperature in the vertical furnace ranges from 500℃ to 750℃; and the original fire channel of the vertical furnace is changed into a hot circulating gas passage. The hot circulating gas passage is uniformly distributed according to the gas amount to ensure uniform gas distribution.

[0046] ​In summary, this utility model has the following characteristics: 1. The heat for dry distillation comes from electrical energy, which is stable, adjustable, and controllable, greatly improving the operational stability and product quality of the pyrolysis furnace; 2. No air is introduced during the heating process of the electric heating furnace 1, which can significantly reduce the content of nitrogen and carbon dioxide in the finished coal gas and increase the content of high-quality gases such as hydrogen, carbon monoxide, and methane, thereby improving the calorific value and quality of the coal gas and reducing the cost and investment of subsequent utilization processes; 3. It can provide sufficient heat according to the needs of the pyrolysis furnace, meeting the requirements of the vertical furnace and enabling the raw coal to achieve complete dry distillation; 4. There is no loss of semi-coke in the vertical furnace, ensuring both product quality and quantity. This patent has a mature principle, reliable structure, convenient operation, and is safe and reliable. It can solve the problems of high useless components and low calorific value of by-product coal gas in existing coal pyrolysis production processes, as well as the impact of combustion reactions in the furnace on production and product quality, thus improving the quality of by-product coal gas and semi-coke products.

[0047] The above examples are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are the same as or similar to this utility model are within the scope of protection of this utility model.

Claims

1. A low-temperature pyrolysis system for electrically heated low-rank coal, characterized in that: It includes an electric heating furnace, a coal pyrolysis furnace, and a gas cooling and purification mechanism that are connected in a sequential cycle. A shut-off valve is installed on the pipeline between the electric heating furnace and the coal pyrolysis furnace, and a regulating valve is installed on the pipeline between the gas cooling and purification mechanism and the electric heating furnace. The gas cooling and purification mechanism is connected to an external transmission pipeline.

2. The electrically heated low-rank coal low-temperature pyrolysis system according to claim 1, characterized in that: It also includes an electrical control cabinet and a flow meter. The flow meter is installed on the pipeline between the gas cooling and purification mechanism and the coal pyrolysis furnace. The flow meter and the regulating valve are both electrically connected to the electrical control cabinet.

3. The electrically heated low-temperature pyrolysis system for low-rank coal according to claim 1, characterized in that: Two electric heating furnaces are provided, one for use and one for standby. A circulating gas pipeline, a tee, a connecting pipeline, and a branch pipeline are provided between the gas cooling and purification mechanism and the electric heating furnace. The outlet of the gas cooling and purification mechanism is connected to the circulating gas pipeline, the circulating gas pipeline is connected to the inlet of the tee, the two outlets of the tee are respectively connected to a connecting pipeline, the outlet of the connecting pipeline is connected to a branch pipeline, and the branch pipeline is connected to the electric heating furnace.

4. The electrically heated low-rank coal low-temperature pyrolysis system according to claim 1, characterized in that: Clean energy electricity is used as the heat source for pyrolysis, and heat is provided by an externally heated gas heat carrier.

5. The electrically heated low-rank coal low-temperature pyrolysis system according to claim 3, characterized in that: The regulating valve is located on the branch line.

6. A low-temperature pyrolysis system for electrically heated low-rank coal according to any one of claims 1-5, characterized in that: The heating rod of the electric heating furnace is a silicon carbide rod.

7. A low-temperature pyrolysis system for electrically heated low-rank coal according to any one of claims 1-5, characterized in that: The shut-off valve is a water-cooled hot air shut-off valve.

8. A low-temperature pyrolysis system for electrically heated low-rank coal according to any one of claims 1-5, characterized in that: The coal pyrolysis furnace includes a top hopper, a vertical furnace, and a bottom coke discharge device. The top hopper is located at the top of the vertical furnace, and the lower part of the vertical furnace is connected to the bottom coke discharge device. The dry distillation temperature range inside the vertical furnace is 500℃-750℃.

9. A low-temperature pyrolysis system for electrically heated low-rank coal according to any one of claims 1-5, characterized in that: The temperature inside the electric heating furnace is 800~1000℃.

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