CN101091867A - Technique for desulfurization in high efficiency for circulating fluidized bed boiler, and for preparing low-heat cement from fly ash - Google Patents

Abstract

The invention provides a technology of preparing low heat cement which uses the highly effective desulphurization and the pulverized coal ash of the circulation fluid bed boiler, the sweetening agent is composed of the following component of percent weight: the quick-lime is 70-95%, fluorspar 1-10%, zinc dregs 1-10%, silicon manganese iron slag 1-10%, titanium dregs 1-10%, when using the sweetening agent,it maintains the calcium sulfur ratio of sweetening agent calcareous quantity and the coal-burning sulphur content is 2.5-10.5:1; the invention includes the following step: takes the various components 42-81% of modified pulverized fly ash, 15-50% of cement clinker with the intensity is the 50-65MPa, 3-8% of the alkalinity excitant, 0-20% of the blast furnace slag, 1-5% of the gypsum, mixes and rubs to 0.045mm sieves and the triage which is smaller than 10%, prepares the coal ash low heat cement whose intensity rank is 32.5- 42.5MPa.

Description

Desulfurization in high efficiency for circulating fluidized bed boiler and preparing low-heat cement from fly ash technology

Technical field

The present invention relates to the technology of a kind of desulfurization in high efficiency for circulating fluidized bed boiler and preparing low-heat cement from fly ash, belong to field of environment engineering.

Background technology

Sulfur dioxide is an important indicator of environmental protection, and its annual environmental carrying capacity is 1,200 ten thousand tons, and China has discharged 2,500 ten thousand tons in 2005, be the first in the world.Atmosphere pollution 90% is from industry, pollute in the industry 70% from thermoelectricity.The energy resource structure 85% of China all is a coal-fired structure, and the annual increase in investment of thermoelectricity certainly leads to a large amount of sulfur dioxide and carbon dioxide more than 50% thus, must carry out strict desulfurization policy in order to reduce environmental pollution.A large amount of coal ash, the slag major part that produces because of fire coal do not obtain comprehensive utilization simultaneously, storing up not only of they occupies cultivated land, and ecological environment is on every side caused serious harm because airborne dust and harmful element leach, directly influence the people's life and health and agricultural development.Therefore the comprehensive utilization of flyash is imperative after the high-efficiency desulfurization of thermoelectricity enterprise and the desulfurization.

Germany LURGI has developed the circulating fluidized bed desulfur technology in the seventies in last century.This technology is by adding the desulfurizing agent lime stone to reach the purpose of desulfurization in recirculating fluidized bed, vulcanizing the characteristic that bed accessory has mass transfer and heat transfer, so can also remove pernicious gases such as HCl and HF when effectively absorbing sulfur dioxide.Because the burning in circulating fluid bed boiler temperature is lower, the nitrogen oxide generation has only 1/3 of other boiler, so CFBB is a kind of combustion apparatus of cleaning.But its present in esse defective is that desulfuration efficiency is lower, can only reach about 50%, does not reach 85% of design load, has simultaneously reduced generating efficiency owing to the decomposition of calcium carbonate has absorbed the part heat; The quality of fly ash of Chan Shenging is poor in addition, can only do low value-added utilizations such as road backfill.

Summary of the invention

The invention discloses the technology of a kind of desulfurization in high efficiency for circulating fluidized bed boiler and preparing low-heat cement from fly ash, not only overcome the aforesaid drawbacks that exists in the present desulfur technology, and can improve the quality of flyash after the desulfurization, and this flyash fully utilized make low-heat cement.

The purpose of this invention is to provide a kind of desulfurizing agent and preparation using method thereof that is used for CFBB.

Desulfurizing agent of the present invention is made up of following components in weight percentage: quick lime 70～95%, fluorite 1～10%, cadmia 1～10%, silicomanganese scum 1～10%, titanium slag 1～10%.

In order to obtain the quality of higher desulfuration effect and modified coal ash, the CaO content in the quick lime is 60～90%, in the fluorite CaF content more than or equal to 75%, in the cadmia ZnO content greater than 2%, in the silicomanganese scum manganese, iron content greater than 2%, TiO in the titanium slag ₂Content is greater than 2%.

When preparing, adopt efficient desulfurizing agent of the present invention the interior general manufacturing process of industry to realize.Also can adopt following method preparation: mix after getting each component in described ratio, being crushed to granularity is that 0.08～2.5mm makes efficient desulfurizing agent.

When using desulfurizing agent of the present invention, desulfurizing agent can be transported in the mixing kettle with belt, by calcium sulfur ratio 2.5～10.5: 1 ratio is mixed with raw coal, feeds the interior realization of CFBB clean combustion again; Also can be with desulfurizing agent in calcium sulfur ratio 2.5～10.5: 1 ratio and fire coal spray into respectively and realize clean combustion in the CFBB.

Quick lime is the primary raw material of desulfurization among the present invention, it not only can generate the effect that gypsum plays desulfurization with sulfur dioxide reaction also can form dicalcium silicate with silicon dioxde reaction in the coal ash, reach improve the flyash that produces mineral composition to improve the purpose of flyash activity.

Desulfurizing agent of the present invention can improve coal-fired inadequate situation in the burner hearth, can improve the efficient of fixed desulfurization in the stove, and desulfuration efficiency can reach more than 90%; And in combustion process, this desulfurizing agent and coal ash component generation combination reaction discharge a large amount of heats, make that burning is more thorough, reached consumption reduction, have economized on coal, improve the resultant effect of flyash quality.Use the flyash that produces behind the desulfurizing agent of the present invention and since its form composition than ordinary fly ash many hydraulicity mineral such as gypsum, dicalcium silicate, the applicant is referred to as modified coal ash.

Another object of the present invention provides a kind of method of utilizing this modified coal ash to prepare the flyash low-heat cement.Preparation process comprises:

1, according to modified coal ash 42～81%, intensity is the clinker 15～50% of 50～65Mpa, alkali-activator 3～8%, and blast-furnace cinder 0～20%, the ratio of gypsum 1～5% is got each component;

2, mix and be milled to 0.045mm and tail over, make the flyash low-heat cement of 32.5～42.5MPa strength grade less than 10%;

Described alkali-activator consists of: CaO 70～90%, Na ₂CO ₃1～10%, Na ₂SO ₄1～10%, NaOH 1～10%, Na ₂SiO ₃1～10%, CaSO ₄2H ₂O 1～10%, blast-furnace cinder 1～20%.

Advantage of the present invention and characteristics:

1, the present invention has realized utilizing multinomial benefits such as high-efficiency desulfurization in the industrial residue, stove, energy-saving and cost-reducing, fly ash highly efficient regeneration utilization.

2, desulfurizing agent of the present invention can improve desulfuration efficiency.

3, can improve the mineral composition of flyash after the desulfurization, improve flyash activity, this modified coal ash can be made 32.5～42.5 flyash low-heat cement with grindings such as clinker, exciting agents, realizes the highly efficient regeneration utilization of recirculating fluidized bed high-efficiency desulfurization and fly ash.

4, collect efficient dry desulfurization, economize on coal, reduce boiler tail wearing and tearing, fly ash efficiently is used in one.

5, desulfurizing agent abundant raw material, cheap.

6, the comprehensive utilization industrial waste of turning waste into wealth, and technology is simple.

7, need not existing boiler and system equipment are changed, only need before and after original system, to add a batching station and grinding station and get final product.

8, small investment.Need only invest about 90 yuan for every kilowatt.

The specific embodiment

In order to understand the present invention better, the present invention is further described by the following embodiment, but do not limit the present invention.

Embodiment 1:

277.5 tons of preparing quick limes, 9 tons in fluorite, industrial residue: 4.5 tons of cadmias, 4.5 tons of silicomanganese scums, 4.5 tons of titanium slags, mixed powder is broken to granularity, and (1.25-2.5mm accounts for 3.04% at 0.08-2.5mm, 0.1-1.25mm account for 40.03%, account for 56.35% less than 0.1mm) be mixed with efficient desulfurizing agent.

Test example 1:

With the efficient desulfurizing agent of embodiment 1 preparation, 13.5 ten thousand kilowatts of fluid bed generating sets carry out type approval test in Henan blue light environmental protection electricity generating corporation, Ltd.Test this power plant's generation load on the same day is that 10.03 ten thousand kilowatts (rate of load condensate 76%) uses that coal-fired sulphur average content is 0.98%, ash content 52.6%, does not drop into that sulfur dioxide in flue gas content mean value is 2400mg/Nm before the desulfurizing agent ³Be that 10.36 ratio sprays into efficient desulfurizing agent in the stove and (feeds coal amount 70t/h with Ca/S, dropping into desulfurization dosage is 10.07t/h), operation is 8 hours continuously, and effluent south inspection center of Bureau of Environmental Protection of Shanxi Province carries out the Continuous Tracking monitoring to the discharging flue gas, does not detect sulfur in smoke content.Be that 5.6 ratio sprays into efficient desulfurizing agent in the stove and (feeds coal amount 70t/h with Ca/S, dropping into desulfurization dosage is 6.2t/h), operation is 8 hours continuously, and effluent south inspection center of Bureau of Environmental Protection of Shanxi Province carries out the Continuous Tracking monitoring to the discharging flue gas, does not detect sulfur in smoke content.Be that 3.0 ratio sprays into efficient desulfurizing agent in the stove and (feeds coal amount 70t/h with Ca/S, dropping into desulfurization dosage is 6.2t/h), operation is 8 hours continuously, and effluent south inspection center of Bureau of Environmental Protection of Shanxi Province carries out the Continuous Tracking monitoring to the discharging flue gas, does not detect sulfur in smoke content.At generation load is 13.0 ten thousand kilowatts (rate of load condensate 96.3% is fed coal amount 105t/h, and dropping into desulfurization dosage is 4.8t/h), and sulfur dioxide in flue gas concentration is 127mg/Nm ³

Embodiment 2:

The preparation of exciting agent: get 8.6 tons of CaO, Na ₂CO ₃0.1 ton, Na ₂SO ₄0.1 ton, NaOH0.25 ton, Na ₂SiO ₃0.22 ton, CaSO ₄2H ₂0.13 ton of % of O, blast-furnace cinder mixes for 0.6 ton, and is standby.

(per hour sampling once to get modified coal ash, the slag that operation produces in the test example 1, continuous sampling mixed in 24 hours), clinker, slag, gypsum and exciting agent, tail over less than 10% to 0.045mm by proportioning in the table 1 and grinding, the flyash low-heat cement that makes reaches 32.5 and 42.5 classification standards respectively.

Numbering	Cement proportion						Rupture strength MPa		Compression strength MPa
											Clinker %	Modified coal ash %	Modified coal ash slag %	Slag %	Gypsum %	Exciting agent %
	3d	28d	3d	28d
					1	20	61	0	10	2							7	3.03	5.7	12.50	36.5
2	30	52	0	10							2	6	4.17	6.9	17.44	48.6
					3	40	43	0	10	2							5	5.05	7.8	23.06	52.3
4	30	0	50	10							2	8	3.63	6.1	13.44	39.6

Embodiment 3:

90 tons of preparing quick limes, 4 tons in fluorite, industrial residue: 2 tons of cadmias, 2 tons of silicomanganese scums, 2 tons of mixed powders of titanium slag are broken to granularity (1.25-2.5mm account for 5.26% at 0.08-2.5mm, 0.1-1.25mm account for 50.44%, account for 44.30% less than 0.1mm) be mixed with efficient desulfurizing agent.

Test example 2:

Efficient desulfurizing agent with embodiment 3 preparations, carry out the test of industry comparison property at 13.5 ten thousand kilowatts of fluid bed generating sets of Henan blue light environmental protection electricity generating corporation, Ltd, test this power plant's generation load on the same day is that 11.05 ten thousand kilowatts (rate of load condensate 81.9%) uses that coal-fired sulphur average content is 1.01%, ash content 53.5%, does not drop into that sulfur dioxide in flue gas content mean value is 2530mg/Nm before the desulfurizing agent ³Be that 5.0 ratio sprays into efficient desulfurizing agent in the stove and (feeds coal amount 78t/h with Ca/S, dropping into desulfurization dosage is 7.6t/h), operation is 8 hours continuously, and effluent south inspection center of Bureau of Environmental Protection of Shanxi Province carries out the Continuous Tracking monitoring to the discharging flue gas, detects sulfur in smoke content 45mg/Nm ³

Embodiment 4:

(per hour sampling once to get modified coal ash, the slag that operation produces in the test example 2, continuous sampling mixed in 24 hours), the exciting agent of preparation among clinker, slag, gypsum and the embodiment 2, tail over less than 10% to 0.045mm by proportioning grinding in the table 1, reach 32.5 and 42.5 classification standards respectively.

Numbering	Cement proportion					Rupture strength MPa		Compression strength MPa
										Clinker %	Modified coal ash %	Slag %	Gypsum %	Exciting agent %
	3d	28d	3d	28d
					1	25	56	10	2						7	3.45	5.8	13.70	38.5
2	35	48	10	2						6	4.74	7.9	18.55	45.8

Claims (5)

1, a kind of desulfurizing agent that is used for CFBB is characterized in that: be made up of following components in weight percentage: quick lime 70～95%, fluorite 1～10%, cadmia 1～10%, silicomanganese scum 1～10%, titanium slag 1～10%.

2, according to the described desulfurizing agent that is used for CFBB of claim 1, it is characterized in that: CaO content is 60～90% in the quick lime, and CaF content is more than or equal to 75% in the fluorite, and ZnO content is greater than 2% in the cadmia, manganese and iron content be all greater than 2% in the silicomanganese scum, TiO in the titanium slag ₂Content is greater than 2%.

3, according to the described preparation method who is used for the desulfurizing agent of CFBB of claim 1, it is characterized in that: get each component in described ratio, mixing and being crushed to granularity is 0.08～2.5mm.

4, according to the described using method that is used for the desulfurizing agent of CFBB of claim 1, it is characterized in that: keeping the calcium sulfur ratio of desulfurizing agent calcium content and coal-fired sulfur content during use is 2.5～10.5: 1.

5, a kind of preparation method of flyash low-heat cement, it is characterized in that: preparation process comprises:

1) according to modified coal ash 42～81%, intensity is the clinker 15～50% of 50～65Mpa, alkali-activator 3～8%, and blast-furnace cinder 0～20%, the ratio of gypsum 1～5% is got each component;

2) mix and be milled to 0.045mm and tail over, make the flyash low-heat cement of 32.5～42.5MPa strength grade less than 10%;

Described alkali-activator consists of: CaO 70～90%, Na ₂CO ₃1～10%, Na ₂SO ₄1～10%, NaOH 1～10%, Na ₂SiO ₃1～10%, CaSO ₄2H ₂O 1～10%, blast-furnace cinder 1～20%.