Method for removing CO2 from biological hydrogen alkane gas by phase-changing solvent prepared from ethylenediamine and DMA (N,N-dimethylacetamide)

Abstract

The invention relates to technologies of energy conservation and environmental protection as well as CO2 emission reduction, and aims to provide a method for removing CO2 from biological hydrogen alkane gas by a phase-changing solvent prepared from ethylenediamine and DMA (N,N-dimethylacetamide). The method comprises steps as follows: after being obtained from ethylenediamine and DMA through mixing, a liquid phase-changing solvent is sent into a spray decarbonization reactor, atomized, sprayed and subjected to countercurrent mixing with biological hydrogen alkane gas; solid precipitates produced through the reaction are subjected to solid-liquid two-phase separation with a liquid DMA solvent, and after gaseous phase products produced from the solid precipitates through heating decomposition are condensed and ethylenediamine is recovered, CO2 gas is collected and sent to a gas storage tank; the liquid DMA solvent obtained through separation, heating and condensation is recycled. With adoption of the novel solid-liquid phase-changing solvent prepared from ethylenediamine and DMA, the removal rate of CO2 in the biological hydrogen alkane gas is increased; compared with a traditionalalkylol amine aqueous solution EDA / H2O, the phase-changing solvent EDA / DMA has the advantages that the CO2 removal rate is increased by 15%-29%, the absorption balance time is shortened by 8%-20%, andCO2 absorption capacity is increased by 10%-21%.

Description

Technical field

[0001] The present invention is about energy saving, environmental protection and CO 2 Emission reduction technology, especially involving the use of ethylenediamine and N,N-dimethylacetamide (abbreviated as DMA) to prepare a two-phase absorbent to remove CO from biohydrogen gas 2 Methods. Background technique

[0002] Due to environmental pollution and energy shortages, biogas treatment and subsequent utilization have received more and more attention. Biphasic fermentation of biomass waste can produce biohydrogen gas, whose main component is CH 4 / H 2 / CO 2 The mixed gas. CO in the mixture 2 Removal can obtain vehicle gas, which can achieve significant environmental and economic benefits.

[0003] Alcoholamine aqueous solutions such as monoethanolamine, diethanolamine and N-methyldiethanolamine have been widely used to absorb CO 2 , But there are problems of high heating energy consumption, reagent volatilization and equipment corrosion during the regeneration of ...

Examples

Embodiment 1

[0024] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with low volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:50, and mechanically stirred at room temperature 5 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 21% H 2 , 40% CH 4 , 38% CO 2 , 0.8% of H 2 S, 0.2% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: the two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous s...

Embodiment 2

[0026] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with low volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:40, and mechanically stirred at room temperature for 10 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 5% H 2 , 63% of CH 4 , 30% CO 2 , 1% H 2 S, 1% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous solut...

Embodiment 3

[0028] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with the low-volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:30, and mechanically stirred at room temperature 15 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 14% H 2 , 35% CH 4 , 50% CO 2 , 0.2% of H 2 S, 0.8% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous ...

Technical field

[0001] The present invention is about energy saving, environmental protection and CO 2 Emission reduction technology, especially involving the use of ethylenediamine and N,N-dimethylacetamide (abbreviated as DMA) to prepare a two-phase absorbent to remove CO from biohydrogen gas 2 Methods. Background technique

[0002] Due to environmental pollution and energy shortages, biogas treatment and subsequent utilization have received more and more attention. Biphasic fermentation of biomass waste can produce biohydrogen gas, whose main component is CH 4 / H 2 / CO 2 The mixed gas. CO in the mixture 2 Removal can obtain vehicle gas, which can achieve significant environmental and economic benefits.

[0003] Alcoholamine aqueous solutions such as monoethanolamine, diethanolamine and N-methyldiethanolamine have been widely used to absorb CO 2 , But there are problems of high heating energy consumption, reagent volatilization and equipment corrosion during the regeneration of ...

Examples

Embodiment 1

[0024] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with low volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:50, and mechanically stirred at room temperature 5 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 21% H 2 , 40% CH 4 , 38% CO 2 , 0.8% of H 2 S, 0.2% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: the two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous s...

Embodiment 2

[0026] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with low volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:40, and mechanically stirred at room temperature for 10 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 5% H 2 , 63% of CH 4 , 30% CO 2 , 1% H 2 S, 1% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous solut...

Embodiment 3

[0028] Weigh the theoretical absorption of CO 2 1.0mol CO capacity 2 / mol chain amine-based absorbent ethylene diamine (EDA), mixed with the low-volatility liquid organic solvent N,N-dimethylacetamide (DMA) at a mass ratio of 1:30, and mechanically stirred at room temperature 15 Minutes, a uniformly mixed EDA / DMA liquid two-phase absorbent is obtained. Use a high-pressure pump to send the liquid two-phase absorbent EDA / DMA into the spray decarburization reactor, and form atomized droplets through the nozzle to flow from top to bottom, and to flow from bottom to top of the biohydrogen gas (volume concentration of each component) 14% H 2 , 35% CH 4 , 50% CO 2 , 0.2% of H 2 S, 0.8% H 2 O) Perform countercurrent mixing. CO in hydrogen gas 2 First, it is physically dissolved in the DMA solvent, and then chemically reacts with the absorbent EDA to form a solid precipitate of EDA-carbamate. The test result is: two-phase absorbent EDA / DMA removes CO 2 Rate ratio alcohol amine aqueous ...

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