CN101870894B - Method and biological plant for removing carbon dioxide, hydrogen sulfide and ammonia from methane by using microecology principle - Google Patents

Abstract

The invention aims to utilize the principle of microecology, and utilize the characteristics that methane gas is insoluble, ammonia is soluble, and carbon dioxide and hydrogen sulfide gas are soluble under the alkaline condition. Blue-green algae can absorb the carbon dioxide dissolved in water and release oxygen through photosynthesis in the presence of nutritional components such as nitrogen and phosphorus; nitrobacteria and nitrite bacteria oxidize the ammonia dissolved in the water into nitrate ions so as to remove the ammonia under the aerobic condition; and under the condition of low oxygen concentration, thiobacteria can oxidize the hydrogen sulfide dissolved in the water into free sulphur so as to remove the hydrogen sulfide gas dissolved in the water. By utilizing the principle of microbial reactions, a method and a device for removing the carbon dioxide, hydrogen sulfide and ammonia from methane by means of the microecological reactions are established.

Description

Remove carbonic acid gas, hydrogen sulfide and ammonia method and biological device in biogas with micro-Ecological Principle

One, technical field:

B01D 53/84；C12P5/00

Utilize micro-Ecological Principle and microbial reaction to remove carbonic acid gas, hydrogen sulfide and ammonia method and biological device in biogas.

Two, background technology:

Biogas is a kind of mixed gas, by methane, and carbonic acid gas, and a small amount of hydrogen, hydrogen sulfide, ammonia, the mixing inflammable gas that carbon monoxide etc. form.Usually, methane accounts for 55% left and right, and carbonic acid gas accounts for 40%, remaining by hydrogen, hydrogen sulfide, a small amount of gas composition such as carbon monoxide.The too high carbon dioxide content of ratio can reduce the combustion heat value of biogas, and the hydrogen sulfide of high-content forms severe corrosive solution after burning, to the metal parts formation corrosion of generating set and pipeline.The restriction that above-mentioned two shortcomings are serious the range of application of biogas, the function of current methane purifying device is all more single, complicated structure, cost is higher, therefore generally only have the large-sized biogas facility just condition adopt.

Three, summary of the invention:

Inventive principle:

The objective of the invention is to utilize the principle of microecology, utilize byproduct and the simple equipment of biogas fermentation, release a kind of easy, cheap, carbonic acid gas in the removal biogas that starting material are easy to get, the method and apparatus of hydrogen sulfide and ammonia.

The present invention is achieved in that biogas is a kind of mainly by methane, carbonic acid gas, and a small amount of hydrogen, hydrogen sulfide, ammonia, the mixing inflammable gas that carbon monoxide etc. form.Usually, methane accounts for 55% left and right, and carbonic acid gas accounts for 40%, remaining by hydrogen, hydrogen sulfide, a small amount of gas composition such as carbon monoxide.Methane gas is insoluble in water, and carbonic acid gas and hydrogen sulfide are soluble in water under alkaline condition at solution.Contain the abundant nutritive ingredient that is easy to be absorbed by plants in natural pond liquid after fermentation, as nitrogen, phosphorus and other nutritive ingredients etc.Blue-green algae is a kind of prokaryotic micro-organisms of low grade, can survive in the water of anoxic.Utilize the inorganic nutrient salt such as nitrogen, phosphorus in water simultaneously, absorb carbonic acid gas the releasing oxygen be dissolved in water by photosynthesis.Nitrobacteria and nitrite bacteria, under the condition of aerobic, can be oxidized to nitrate ion by the free ammonia in water, and the form of the best nitrogen that nitrate ion is blue-green algae can directly be absorbed.Simultaneously, under the condition existed at faint oxygen, a lot of thiobacteriums can become the Oxidation of Hydrogen Sulfide dissolved in water the free sulfur precipitation, thereby remove the hydrogen sulfide dissolved in water.The present invention is exactly the principle of utilizing the mentioned microorganism reaction, sets up the bio-reactor of a set of dependence microecosystem, removes carbonic acid gas, hydrogen sulfide and ammonia in biogas.

Beneficial effect:

Because biogas contains a large amount of carbon dioxides, usually can reach 40% (V/V), serious reduction the combustion heat value of biogas.Simultaneously, biogas contains a large amount of hydrogen sulfide, and the gas that produces severe corrosive when burning damages pipeline and the generating set of metal.This has greatly limited and has used the universal of marsh gas power generation.Present method is utilized the byproduct of biogas production and the microorganism that occurring in nature easily obtains, and by the method for microecology, combines the carbonic acid gas reduced in biogas, the content of hydrogen sulfide and free ammonia.Present method principle is clear and definite, and implementing process is simple, simple in equipment, and the whole plant cost is cheap, the raw materials used byproduct all produced from biogas fermentation, therefore suitable various types of methane-generating pit adopts, and the biogas that purification produces is for the needs that generate electricity.

Four, accompanying drawing explanation:

See that accompanying drawing 1, microorganism marsh gas purifying equipment illustrate

1, intake ducting; 2, the gaseous diffuser of multiple exit; 3, the meta-alkalescence nutritive medium that is main preparation by natural pond liquid; 4, outlet pipe and pressure limiting valve; 5, be connected to the photosynthetic response solution of categories of blue algae; 6, oxidative nitration reactor; 7, bioaffinity protruded packing; 8, water pump; 9, photosynthetic reactor; 10, the emptying pressure limiting valve of oxygen; 11, oxygen emptying pipe

Five, concrete embodiment:

Reactor R is by the scatterers 2 of a plurality of gases that scatter mouthful, inner micro-weakly alkaline nutritive medium 3, and the outlet pipe of top band limited valve door 4 forms.

Biogas enters in the liquid 3 in reactor R by the scatterers 2 that a plurality of distribution mouths are arranged along intake ducting 1.It is in order to increase the contact area of liquid 3 in biogas and reactor R that scatterer 2 is designed with a plurality of distributions mouthful, increases carbonic acid gas in biogas, the solubleness of hydrogen sulfide and ammonia.Individual pressure limiting valve is arranged at reactor R top, can maintain in reactor R and maintain certain pressure.Nutritive medium 3 in reactor R is that the master adds a small amount of inorganic salt dilution formulated by the natural pond liquid after biogas fermentation, and adds appropriate sodium carbonate, maintains the weakly alkaline of nutritive medium 3 at pH7.5-pH8.5.Add sodium carbonate to make nutritive medium 3 present the weakly alkaline dissolving power of liquid 3 for carbonic acid gas and hydrogen sulfide that can have additional nutrients.

The upper end of photosynthetic reactor 9 has pipeline to be connected with oxidative nitration reactor 6.Photosynthetic reactor 9 is made by transparent material, inside has inoculation that categories of blue algae is arranged.There is the filler 7 of bioaffinity oxidative nitration reactor 6 inside, the thiobacteriums such as inoculation nitrobacteria and nitrite bacteria and thiobacillus denitrificans, thiobacillus thiooxidans on filler.

When the ambient lighting condition is better, water pump 8 work, the saturated liquid 3 that carbonic acid gas and hydrogen sulfide is arranged and be dissolved with ammonia is entered to photosynthetic reactor 9 through water pumps 8, because itself containing, the liquid 3 by the preparation of natural pond liquid enriches compound fertilizer, and the carbonic acid gas CO2 gas of saturated dissolving, very suitable blue algae growth.Blue-green algae, by photosynthesis, consumes carbonic acid gas releasing oxygen in nutritive medium 3, reaction equation (a).A large amount of oxygen that photosynthesis produces enter specific container by pressure limiting valve 10 by pipeline 11 and recycle or emptying.Now, nutritive medium 3 is the state that dissolves saturated oxygen by the state-transition of dissolving saturated carbonic acid gas, contains the nutritive medium 3 that enriches oxygen and naturally flows in oxidative nitration reactor 6.The filler 7 epimere growths of oxidative nitration reactor 6 have aerobic nitrobacteria and nitrite bacteria.Under the condition of hyperoxia, the free ammonia in water is oxidized into nitrate ion, and consumes the dissolved oxygen in water, reaction equation (b); The consumption of the bacterium of process oxidative nitration reactor 6 interior filler 7 aerobic sections, the saturated oxygen of nutritive medium 3 interior dissolvings is consumed, nutritive medium 3 transfers hypoxia to, low oxygen area is formed at the bottom at the interior filler 7 of oxidative nitration reactor 6, under the condition of hyperoxia or hypoxemia, thiobacillus denitrificans, thiobacillus thiooxidans, thiobacillus ferrooxidant, grate sulfur thiobacillus, thread thiobacterium, family name's sulphur Pseudomonas, distinguish that the thiobacteriums such as sulphur Pseudomonas, Thiothrix can become Oxidation of Hydrogen Sulfide simple substance S or SO₄^2-thereby, the hydrogen sulfide in biogas is removed.Reaction equation (c), (d).

Through above-mentioned circulation, nutritive medium 3 is dissolved with saturated carbonic acid gas out the time by reactor R, and hydrogen sulfide and dissolve ammonia and be consumed or transform reenters in reactor R, continues carbonic acid gas, hydrogen sulfide and ammonia in biogas in dissolution reactor R.And continue to be pumped in photosynthetic reactor 9 by water pump 8, repeat aforesaid circulation.And so forth, continuous carbonic acid gas, hydrogen sulfide and the ammonia in the biogas of absorption reactor thermally R top of whole system.Nutrition in nutritive medium 3 is consumed light, or blue algae growth density is when too high, can maintain the stable of reaction and carries out by adding new nutritive medium or discharging excessive blue-green algae.

6CO₂+6H₂O→C₆H₁₂O₆+6O₂ (a)

NH₃+2O₂→NO₃^-+H₂O+H⁺ (b)

2H₂S+O₂→2S+2H₂O (c)

2S+3O₂+2H₂O→2H₂SO₄ (d)

Claims (1)

1. one kind is utilized micro-Ecological Principle and microbial reaction to remove carbonic acid gas in biogas, the method of hydrogen sulfide and ammonia, it is by gas reactor R, transparent photosynthetic reactor forms with the oxidative nitration reactor that multiporous biological affinity packing material is housed, it is characterized in that: in described gas reactor R, being full of by the natural pond liquid after biogas fermentation is main formulated nutritive medium, and by adding carbonate to make nutritive medium be weakly alkaline, the dissolving power of liquid for carbonic acid gas and hydrogen sulfide has additional nutrients, the upper end of described photosynthetic reactor has pipeline to be connected with the oxidative nitration reactor, in described photosynthetic reactor, inoculation has categories of blue algae, under illumination condition, the saturated nutritive medium that carbonic acid gas and hydrogen sulfide is arranged and be dissolved with ammonia is entered to photosynthetic reactor through water pump, pass through photosynthesis, blue-green algae utilizes the nitrogen in nutritive medium, phosphorus composition, absorbing carbon dioxide is also emitted oxygen, nutritive medium is the state that dissolves saturated oxygen by the state-transition of dissolving saturated carbonic acid gas, contain the nutritive medium that enriches oxygen and naturally flow to the oxidative nitration reactor, described oxidative nitration inside reactor has the organism compatibility filling of porous, on described filler, inoculation has nitrobacteria, nitrite bacteria and thiobacterium, the filler epimere growth of oxidative nitration reactor has aerobic nitrobacteria and nitrite bacteria, free ammonia in the hyperoxia Water Under is oxidized to nitrate ion, and the dissolved oxygen in consumption water, in the oxidative nitration reactor, low oxygen area is formed at the bottom of filler, under the condition of hyperoxia or hypoxemia, thiobacterium can become Oxidation of Hydrogen Sulfide simple substance S or SO₄^2-thereby the hydrogen sulfide in biogas is removed, and through above-mentioned circulation, the ammonia of saturated carbonic acid gas, hydrogen sulfide and dissolving that nutritive medium is dissolved out the time by reactor R is digested or transform, reenter in reactor R, continue the carbonic acid gas in biogas in dissolution reactor R, hydrogen sulfide and ammonia, and continue to be pumped in photosynthetic reactor by water pump, repeat aforementioned circulation, and so forth, continuous carbonic acid gas, hydrogen sulfide and the ammonia in the biogas of absorption reactor thermally R top of whole system.