Method for synthesizing hydrogen cyanide from carbon-containing solid and ammonia gas

Abstract

The invention discloses a method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia gas, and belongs to the technical field of hydrogen cyanide production. The method comprises the following steps: contacting ammonia gas with a carbon-containing solid heated to a reaction temperature, and carrying out a gas-solid reaction to generate a high-temperature gas containing hydrogen cyanide; according to the invention, the technical route that the existing hydrogen cyanide production technology mainly depends on a gaseous hydrocarbon carbon source, a noble metal catalyst and external combustion heat supply is changed, and the problems of limited raw material sources, easiness in catalyst deactivation, slow process start-stop response and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen cyanide production technology, and specifically relates to a method for synthesizing hydrogen cyanide from carbon-containing solids and ammonia. Background Technology

[0002] Hydrogen cyanide (HCN) is an important basic chemical raw material, widely used in the synthesis of adiponitrile, acrylonitrile, and methyl methacrylate, as well as in the production of various pharmaceuticals, pesticides, and polymer materials. Due to its crucial role in the downstream industrial chain, developing efficient, stable, and economical hydrogen cyanide preparation technologies has always been a key focus in this field.

[0003] Currently, the mainstream industrial routes for hydrogen cyanide production are the Angle process and the BMA process. These methods typically use methane or other low-carbon hydrocarbons as carbon sources, reacting them with ammonia at high temperatures to produce hydrogen cyanide. To obtain sufficient reaction rates and selectivity, these processes generally operate above 1000 °C and rely on noble metal (Pt, Ag) catalysts or high-performance catalytic systems to maintain the reaction. To address the problem of catalysts being prone to sintering, carbon deposition, or poisoning and deactivation under high-temperature conditions, existing technologies have made improvements in several aspects. For example, Chinese patent applications CN1756721A and CN107073452A extend catalyst lifespan by optimizing catalyst composition; Chinese patent application CN104016375A improves reaction uniformity by modifying the gas mixer structure; and Chinese patent application CN110127724A enhances overall energy utilization efficiency by strengthening waste heat recovery. However, these improvements still use gaseous hydrocarbons as carbon sources and rely on catalytic systems, failing to fundamentally change the raw material structure and reaction mode of hydrogen cyanide synthesis.

[0004] Carbon-containing solids, such as coke and biochar, are widely available, abundant, inexpensive, and relatively stable. Developing novel hydrogen cyanide reaction pathways and methods using carbon-containing solids as carbon sources, while simultaneously achieving efficient thermal management and reaction intensification, would revolutionize existing processes and eliminate dependence on gaseous hydrocarbon feedstocks and precious metal catalysts for hydrogen cyanide production.

[0005] Therefore, this application is hereby submitted. Summary of the Invention

[0006] This invention provides a method for synthesizing hydrogen cyanide from carbon-containing solids and ammonia without the need for a catalyst. This method changes the existing hydrogen cyanide production technology, which mainly relies on gaseous hydrocarbon carbon sources, precious metal catalysts, and external combustion heating. It solves the problems of limited raw material sources, easy catalyst deactivation, and slow process start-up and shutdown response in existing hydrogen cyanide production technologies.

[0007] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: This invention provides a method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia gas. Ammonia gas is brought into contact with a carbon-containing solid heated to the reaction temperature, and a gas-solid reaction occurs to produce a high-temperature gas containing hydrogen cyanide.

[0008] The reaction can be carried out in an inorganic reaction tube. A carbon-containing solid is placed inside the tube, and eddy currents are generated inside through electromagnetic induction, directly heating it to a high temperature. The generated high-temperature hydrogen cyanide gas is rapidly cooled to suppress side reactions and increase the yield of hydrogen cyanide. At the same time, the heat is recovered and can be used to preheat ammonia, improving the overall thermal efficiency.

[0009] The method can achieve precise control over the heating rate and final temperature of carbon-containing solids by adjusting the output power and frequency of electromagnetic induction.

[0010] The method can be operated in a continuous mode, in which ammonia gas is continuously introduced into the reaction tube and reacts with high-temperature carbon, and the generated product gas is continuously discharged.

[0011] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses carbon-containing solids as the carbon source for the synthesis of hydrogen cyanide. The raw materials are widely available, stable, inexpensive and readily available, which reduces the dependence on gaseous hydrocarbon carbon sources.

[0012] (2) This invention does not require precious metal catalysts, has no catalyst cost, and has no catalyst deactivation problem.

[0013] (3) The high temperature required by the present invention can be generated directly by carbon-containing solid through electromagnetic induction, which has the characteristics of rapid start-up and shutdown, precise temperature control, flexible operation, short heat transfer path and high heat utilization rate. Detailed Implementation

[0014] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0015] Unless otherwise specified in the embodiments of the present invention, the conditions shall be performed in accordance with conventional conditions or conditions recommended by the manufacturer.

[0016] In this invention, the ammonia conversion rate and hydrogen cyanide yield are calculated using the following formulas: Ammonia conversion rate = ((inlet ammonia content - outlet ammonia content) / inlet ammonia content) × 100%.

[0017] Hydrogen cyanide yield = (outlet hydrogen cyanide amount / inlet ammonia amount) × 100%.

[0018] Ammonia levels were determined by gas chromatography, and hydrogen cyanide levels were determined by silver nitrate titration (YB / T 4495-2015).

[0019] An embodiment of the present invention discloses a method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia gas. The ammonia gas comes into contact with (or "passes through the carbon-containing solid") a carbon-containing solid heated to the reaction temperature, and a gas-solid reaction occurs to produce a high-temperature gas containing hydrogen cyanide.

[0020] In a preferred embodiment, the carbon-containing solid is placed in an inorganic material reactor, and eddy currents are generated inside the carbon-containing solid by electromagnetic induction, which directly heats it to the reaction temperature.

[0021] In some embodiments, the reaction temperature is 1000-2000 °C. In some preferred embodiments, the reaction temperature is 1300-1700 °C.

[0022] In some embodiments, the frequency of the electromagnetic induction is 10-2000 kHz. In some preferred embodiments, the frequency of the electromagnetic induction is 200-1000 kHz.

[0023] In some embodiments, the residence time of ammonia gas in the reactor is 0.01-1 s. In some preferred embodiments, the residence time of ammonia gas in the reactor is 0.05-0.2 s.

[0024] The temperature of the carbon-containing solid is regulated by adjusting the frequency and power of electromagnetic induction. The reaction time between ammonia and carbon is regulated by adjusting the ammonia flow rate according to the porosity of the carbon-containing solid. An infrared thermometer is used to monitor the reaction temperature in real time.

[0025] In optional embodiments, the carbon-containing solid includes one or more of petroleum coke, metallurgical coke, coal coke, biochar, graphite, or graphitized products of carbon-containing raw materials. In some preferred embodiments, the carbon-containing solid can be coal coke, biochar, or graphite. From a green and environmentally friendly perspective, biochar is more preferred.

[0026] In optional embodiments, the carbon-containing solid may have one or more of the following shapes: granular, honeycomb, and foam. In some preferred embodiments, the granular shape may have one or more of the following shapes: blocky, columnar, or spherical.

[0027] In some embodiments, the volume of the carbon-containing solid particle is 2.5-10 cm³. 3 .

[0028] In some embodiments, the electrical conductivity of the carbon-containing solid is 10-10000 S / m. In some preferred embodiments, the electrical conductivity of the carbon-containing solid is 200-9000 S / m.

[0029] The preferred selection of conductivity, shape, and volume is mainly to improve the heating capacity of carbon-containing solids in electromagnetic induction fields. Carbon-containing solids with larger size and higher conductivity can generate stronger eddy currents, exhibit higher heating rates, and can reach higher reaction temperatures.

[0030] In some embodiments, the high-temperature gas containing hydrogen cyanide is rapidly cooled to suppress side reactions and increase the yield of hydrogen cyanide, while simultaneously recovering heat, which can be used to preheat ammonia and improve overall thermal efficiency.

[0031] In some preferred embodiments, ammonia is preheated before being passed through a carbon-containing solid. Example 1

[0032] A method for synthesizing hydrogen cyanide from carbon-containing solids and ammonia: The volume is 3.20 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 350 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 38%. Example 2

[0033] The volume is 3.20 cm 3 Block graphite with an electrical conductivity of 8900 S / m was placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, where it reacted with the high-temperature block graphite to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 80 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 32%. Example 3

[0034] The volume is 3.20 cm 3 Lump coal char with an electrical conductivity of 280 S / m is placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) is continuously introduced into the reactor, where it undergoes a gas-solid reaction with the hot lump coal char to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas is then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency is 400 kHz, the residence time of ammonia gas in the reactor is 0.05 s, the ammonia conversion rate is 100%, and the hydrogen cyanide yield is 36%. Example 4

[0035] The volume is 3.20 cm 3 Honeycomb biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the high-temperature honeycomb biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 350 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 40%. Example 5

[0036] The volume is 3.20 cm 3 Foamy biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the high-temperature foamy biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 350 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 42%. Example 6

[0037] The volume is 3.20 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1850℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 600 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 28%. Example 7

[0038] The volume is 3.20 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1300℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 280 kHz, the residence time of ammonia gas in the reactor was 0.05 s, the ammonia conversion rate was 75%, and the hydrogen cyanide yield was 17%. Example 8

[0039] The volume is 3.20 cm 3Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1300℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 280 kHz, the residence time of ammonia gas in the reactor was 0.1 s, the ammonia conversion rate was 82%, and the hydrogen cyanide yield was 21%. Example 9

[0040] The volume is 3.20 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1300℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 280 kHz, the residence time of ammonia gas in the reactor was 0.2 s, the ammonia conversion rate was 90%, and the hydrogen cyanide yield was 27%. Example 10

[0041] The volume is 1.36 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1300℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 350 kHz, the residence time of ammonia gas in the reactor was 0.2 s, the ammonia conversion rate was 90%, and the hydrogen cyanide yield was 27%. Example 11

[0042] The volume is 3.20 cm 3 Block biochar with an electrical conductivity of 320 S / m was placed in a corundum tube reactor and self-heated to 1500℃ in an electromagnetic induction field. High-purity ammonia gas (99.9% purity) was continuously introduced into the reactor, reacting with the hot-temperature block biochar to form a high-temperature gas containing hydrogen cyanide. The high-temperature product gas was then rapidly cooled to obtain hydrogen cyanide. The electromagnetic induction frequency was 350 kHz, the residence time of ammonia gas in the reactor was 0.2 s, the ammonia conversion rate was 100%, and the hydrogen cyanide yield was 32%. Example 12

[0043] The difference from Example 1 is that the ammonia gas is preheated to 1000°C before being passed through the high-temperature block biochar. The required electromagnetic induction frequency is 280 kHz, the ammonia conversion rate is 85%, and the hydrogen cyanide yield is 23%.

[0044] Table 1 Comparison of parameters and test results for each embodiment Serial Number carbon matter <![CDATA[Volume cm 3 > Conductivity S / m Inductor frequency kHz Reaction temperature / ℃ Ammonia reaction time / s Ammonia conversion rate / % Hydrogen cyanide yield / % Example 1 Block biochar 3.20 320 350 1500 0.05 100 38 Example 2 Massive graphite 3.20 8900 80 1500 0.05 100 32 Example 3 Lump coal coke 3.20 280 400 1500 0.05 100 36 Example 4 Honeycomb biochar 3.20 320 350 1500 0.05 100 40 Example 5 Foam biochar 3.20 320 350 1500 0.05 100 42 Example 6 Block biochar 3.20 320 600 1850 0.05 100 28 Example 7 Block biochar 3.20 320 280 1300 0.05 75 17 Example 8 Block biochar 3.20 320 280 1300 0.1 82 21 Example 9 Block biochar 3.20 320 280 1300 0.2 90 27 Example 10 Block biochar 1.36 320 350 1300 0.2 90 27 Example 11 Block biochar 3.20 320 350 1500 0.2 100 32 Example 12 (Ammonia Preheating) Block biochar 3.20 320 280 1300 0.05 85 23 It can be seen that different carbon materials have different effects on the yield of hydrogen cyanide, and the yield of hydrogen cyanide is lower when graphite is used as the carbon source.

[0045] Meanwhile, by comparing Examples 12 and 7, it was found that preheating ammonia before passing it through a high-temperature carbon-containing solid improved the hydrogen cyanide yield and contributed to energy conservation and efficiency.

[0046] When the reaction temperature is set at 1300℃, extending the reaction time helps to form hydrogen cyanide; when the reaction temperature is set at 1500℃, extending the reaction time actually reduces the yield of hydrogen cyanide.

[0047] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia, characterized in that, When ammonia comes into contact with a carbon-containing solid heated to the reaction temperature, a gas-solid reaction occurs, producing a gas containing hydrogen cyanide.

2. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, Eddy currents are generated inside the carbon-containing solid using electromagnetic induction, causing the carbon-containing solid to be directly heated to the reaction temperature.

3. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 2, characterized in that, The frequency of the electromagnetic induction is 10-2000 kHz.

4. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, The residence time of the ammonia gas in the reactor is 0.01-1 s.

5. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, The carbon-containing solids include one or more of petroleum coke, metallurgical coke, coal coke, biochar, graphite, or graphitized products of carbon-containing raw materials. The shape of the carbon-containing solid includes one or more of the following: granular, honeycomb, and foam.

6. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 5, characterized in that, The granular form includes one or more of the following: blocky, columnar, or spherical.

7. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 5 or 6, characterized in that, The volume of the carbon-containing solid particles is 2.5-10 cm³. 3 .

8. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, The reaction temperature is 1000-2000 ℃.

9. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, The electrical conductivity of the carbon-containing solid is 10-10000 S / m.

10. The method for synthesizing hydrogen cyanide from a carbon-containing solid and ammonia according to claim 1, characterized in that, The hydrogen cyanide-containing gas is rapidly cooled to suppress side reactions and recover heat.