CN107001956B

CN107001956B - Carbon-molecule gasification combustion boiler power generation method

Info

Publication number: CN107001956B
Application number: CN201480065842.3A
Authority: CN
Inventors: 陈涛; 陈科正; 陈科斌; 陈俊丽; 其他发明人请求不公开姓名
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-08-15
Filing date: 2014-12-08
Publication date: 2021-05-04
Anticipated expiration: 2034-12-08
Also published as: CN107001956A; CN104152181A

Abstract

A carbon-molecule gasification combustion power generation method comprises the following main processes: adding desulfurizer coal, desulfurizing and gasifying into clean coal gas in a molecular gasifier; mixing hot coal gas with low excess air, and burning in a hearth of a boiler; according to the coal quality and the requirement, the coal coke can be refined and the dust can be removed; the high-temperature flue gas exchanges heat through a heating surface of the boiler and is discharged from a chimney after reaching the standard; the steam generated by the boiler drives a steam turbine to generate electricity. The gasification method can also be applied to a gas internal combustion engine and a gas turbine power generation system in a matching way to manufacture the required cold coal gas; but also can produce chemical raw material gas. The method has wide application range, simple process, safe operation, environmental protection and energy conservation.

Description

Carbon-molecule gasification combustion boiler power generation method

Application of the invention

The priority of the invention is two Chinese patent applications: 201310653009.8, a carbon molecule gasification combustion method for a coal-based boiler of a power plant; 201410400491.9, carbon-molecule gasification combustion boiler (kiln) process.

Technical Field

The invention relates to a clean coal-fired power generation method, in particular to a gasification combustion boiler power generation method with coal designed from a molecular level.

Background

Currently, climate change, environmental deterioration and resource shortage are worldwide problems. Energy conservation, emission reduction and climate change response also become a hotspot and focus for the transition from technology to international politics.

The current energy situation of China is that coal is much, oil is little, gas is poor, and the China is a major energy producing and consuming country mainly using coal. Coal consumption accounts for half of the total world amount, and more than 80 percent of the coal consumption still adopts the traditional direct combustion mode (grate layer combustion, fluidized bed combustion, pulverized coal combustion, coal briquette and coal water slurry combustion, and the like). The environmental science considers that: the direct combustion mode of coal is also a main pollution source for generating dust haze in China at present.

However, this direct coal burning method is still used worldwide in the future. For example, the international energy agency 2021 and 2050 years high-efficiency low-emission coal-fired power generation technical route still adopts the direct combustion technology of a circulating fluidized bed boiler and a pulverized coal boiler. China also uses the circulating fluidized bed boiler and the pulverized coal boiler as important technologies for future development. This is not primarily recognized from basic theory: the direct combustion method mixes the solid phase matter in coal and the pyrolyzed gas phase matter together, and burns in the same hearth, thus breaking the characteristics and law of respective combustion of the gas phase matter and the solid phase matter. To complete the direct combustion, excess air (α ≧ 1.2) is employed, which results in the loss of air, and instead, a large amount of toxic and harmful pollutants (SOx, NOx, etc.) associated with oxygen are produced in the combustion process before treatment. Therefore, the process is complex, the cost is high, and even the conditions that the discharge of 'pollution treatment and pollution generation' is unstable and the pollution treatment is difficult to reach the standard are caused.

The coal-based IGCC technology developed all over the world at present has high power generation efficiency, but the benefit is not necessarily high. Moreover, the popularization and application are greatly limited at present due to the problems of complex process, difficult operation, high operation cost, large investment and the like. The root cause is researched: is caused by the adoption of the traditional coal gasification technology with high specific surface area, high temperature and high pressure.

For the above technical process, the efficiency thinking and common standard of the habits all over the world are measured as follows:

Q_{practical coal energy}/(Q_{Total original energy of coal}) Maximum ═ maximum

(B_{Discharge of coal pollution})/B_{Total amount of original pollutants of coal}Min ═ min

Disclosure of Invention

Aiming at the current situation, the invention provides the concept of coal utilization according to the energy environmental protection benefit:

Q_{practical coal energy}/(Q_{Total original energy of coal}+ _{Total energy consumption of coal utilization process}Q) Maximum ═ maximum

(B_{Discharge of coal pollution}+ _{Total amount of pollution control discharge}B)/B_{Total amount of original pollutants of coal}Min ═ min

And carrying out comprehensive quantitative assessment and development. Therefore, the process is innovated, and a coal gasification combustion boiler power generation method designed from the molecular level is provided. The process has the advantages that: the pollution is prevented and controlled from the source, the elements are reduced, and the environmental protection and energy saving are realized with high efficiency.

The technical route to achieve this goal is: firstly, raw material coal added with a desulfurizer is fed into a molecular gasification furnace to be desulfurized and gasified into clean hot coal gas, then the clean hot coal gas is sprayed into a boiler to be combusted, high-temperature flue gas is discharged from a chimney after heat exchange of a heating surface of the boiler, and steam (hot water) generated by the boiler drives a steam turbine to generate (supply) heat.

The molecular gasification furnace adopts a mechanism of coupling a large-interface thin material layer with a complete oxidation reaction and a small-section thick material layer with a forward reduction reaction to produce gas; the reduction region of the molecular gasification furnace is additionally provided with an annular temperature measuring point, the oxidation region is correspondingly provided with an annular steam spray hole, and during operation, the temperature of the measuring point can be regulated and controlled by steam, and the regional regulation and control can meet the process requirements in time and in a balanced manner, so that the gasification reaction is ensured to be carried out stably; the molecular gasification furnace uses a desulfurizer to remove sulfur under the condition of oxygen deficiency (Ca/S is close to 1 proportion of components); the hot coal gas is combusted in a hearth of the boiler by adopting a low excess air coefficient (alpha is close to 1), so that more than 10 percent of air is saved, and the generation of toxic and harmful substances related to oxygen is reduced; the lower part of the boiler is additionally provided with a coke (dust) removal cavity which has double functions of coal coke refining and dust removal; the operation process can refine coal coke according to the coal quality and the requirement, and can also be converted into a combustion dust removal function at any time.

Drawings

FIG. 1 is a flow diagram of a typical gasification combustion boiler power generation process of the present invention.

FIG. 2 is a diagram of a typical modified molecular gasifier and control system of the present invention.

FIG. 3 is a block diagram of a typical symmetrical arrangement of burners from both sides of a boiler in accordance with the present invention.

FIG. 4 is a block diagram of a typical three sided arrangement of burners from a boiler in accordance with the present invention.

FIG. 5 is a structural view of a burner of the present invention arranged from the side of a boiler (kiln).

FIG. 6 is a structural diagram of a four-side symmetric burner of an ultra-large boiler according to the present invention.

Detailed Description

The invention is described in detail below with reference to figures 1, 2, and 3 and specific embodiments:

the raw coal is screened to obtain the pea coal A, the pulverized coal with the particle size smaller than 10mm is added with calcium (the Ca/S is close to 1 proportion component) to prepare a coal ball B, the coal ball B is dried by waste heat to form a dry coal ball C with qualified water content (the coal preparation system saves more than 50 percent of electricity compared with a coal pulverizing system), and the pea coal A and the dry coal ball C are sent into a molecular gasification furnace 1 by a coal feeder to make gas; the gasification agent is fed from the bottom of the furnace through the grate (the pressure of the gasification agent for preparing fuel gas is generally less than 0.5kpa, which is reduced by 58% compared with the wind pressure of the existing pulverized coal and fluidized bed combustion technology which is more than or equal to 1.2kpa, and the electricity is saved by 58% correspondingly); the slag is discharged from the bottom of the furnace by a grate. The molecular gasification furnace 1 adopts the original mechanism that the complete oxidation reaction of a large-interface thin material layer is 1-6 coupled with the forward reduction reaction of a small-section thick material layer is 1-5 to produce gas, and the gasification process designed from the molecular level can ensure the orderly reaction in the furnace, thereby efficiently improving the gasification yield (the same coal quality and the same yield, and the running power consumption is less than that of the existing high-temperature and high-pressure entrained flow bedAnd 1% of fluidized bed gasification); the complete oxidation reaction 1-6 of the large-interface thin material layer is realized by the structure of the lower oxidation section of the molecular gasification furnace 1, the raw material is spread into a thin layer in a large area, and the contact interface between the thin layer and the gasification agent sprayed in the inner grates 1-8 and the outer grates 1-7 is enlarged, so that the oxidation reaction C + O is accelerated₂＝CO₂The progress speed of + Q is more complete; the forward reduction reaction 1-5 of the small-section thick material layer is formed and realized by the structure at the upper part of the molecular gasification furnace 1: it makes CO₂Extended contact time between reactants when + C ═ 2 CO-Q; the flow velocity of the rising thermal fluid is improved, so that the convective heat transfer and mass transfer effects are accelerated, and the temperature of the raw material column at the reduction section is raised; meanwhile, the amount of the reactant carbon dioxide is rapidly complemented, and the factors inevitably accelerate the reduction reaction so that the reaction is fully and completely carried out; in order to ensure that the reaction temperature is balanced and meets the process requirements, an annular temperature measuring point 1-2 is additionally arranged in an upper reduction area of the molecular gasification furnace 1, an annular steam jet hole 1-1 is also arranged in a lower oxidation area, and when the temperature of the measuring point exceeds a specified value and the annular temperature difference exceeds a certain value (determined according to the coal quality) in operation, a control system automatically (manually) opens steam of the lower spray pipe 1-1 for regulation and control (the regional regulation and control is timely, accurate and effective); the molecular gasification furnace 1 uses coal to add calcium to remove sulfur and produce gas under the anoxic condition, so the components can be designed according to the sulfur content and the emission index of raw coal and the proportion of Ca/S close to 1, thereby realizing the goal of reaching the standard of sulfur removal with high benefit; discharging calcium-containing slag from the furnace bottom by using a grate, and reusing the calcium-containing slag as a cement raw material; hot coal gas enters an outer burner 2 and passes through a decoking cavity (combustion chamber) 6 (the decoking cavity 6 has double functions of coal coke refining and dust removal: 1, according to the coal quality and requirements, an air valve of the outer burner 2 is closed to enable the decoking cavity to play the role of inertia impulse to refine coal coke which is a raw material for producing coal-based activated carbon, 2, the hot coal gas can be converted at any time according to requirements, and air is opened and controlled to cooperate with the hot coal gas for combustion and dust removal), and then enters an inner burner 5 to be burnt out in a hearth; the hot coal gas is combusted by adopting a low excess air coefficient (alpha is close to 1) (namely, the air is saved by more than 10 percent, and the generation of toxic and harmful substances SOx, NOx and the like related to oxygen is correspondingly reduced), and the hot coal gas is highThe warm flue gas is discharged from a chimney after reaching the standard through heat exchange of the heating surface of the boiler 3. The gasification combustion process prevents and controls pollution from the source, reduces elements, and is beneficial to realizing environmental protection and energy conservation. The steam (hot water) generated by the boiler 3 drives a steam turbine to generate electricity (supply heat).

FIG. 2 is a view of a typical modified molecular gasification furnace 1 and control system of the present invention, and 1-1 is an annular steam injection hole; 1-2 is an annular temperature measuring hole; 1-3 is a coal feeding port; 1-4 is a gas outlet; 1-5 is a small-section thick material layer reduction reaction area; 1-6 is a large interface thin material layer oxidation reaction zone; 1-7 is an outer grate; 1-8 is an inner grate; discharging slag from the furnace bottom; the gasifying agent is sprayed in through the grate. The molecular gasification furnace 1 and the gasification method can produce clean hot coal gas, and burn boilers and various kilns with high benefit; the cold coal gas can also be applied to a gas internal combustion engine and a gas turbine power generation system in a matching way to manufacture the required cold coal gas; can also produce chemical raw material gas; the gasification yield is high, and the gasification strength index is 1000-2600 kg/m²H, can be large-scaled (several thousand tons per day for a single furnace); the operation cost is low (the power consumption is not 1% of that of the entrained flow bed and the fluidized bed with the same coal quality and the same yield).

FIG. 3 is a structural view of an exemplary outer burner of the present invention symmetrically disposed from both sides of a boiler, and FIG. 2 is a gas-blowing outer burner which can open and close and control air; 3, a boiler hearth; 4 is a coke (dust) discharging port; 5 is an inner burner; 6 is a cavity (combustion chamber) which can remove coal coke (dust); 7 is the gas chamber of the burner; 8 is the air chamber of the burner; 9 is a wall shell of the inner burner, and air jet holes are arranged on the wall shell; 10 is the air chamber of the inner burner.

FIG. 4 is a block diagram of an exemplary outer burner of the present invention positioned from three sides of a boiler, and FIG. 2 is a downward blowing outer burner; and 3, a boiler furnace.

FIG. 5 is a structural view of a burner disposed at one side of the small boiler of the present invention, and FIG. 2 is a downward blowing outer burner; and 3, a boiler furnace.

FIG. 6 is a structural diagram of downward blowing burners symmetrically arranged on four sides of an ultra-large boiler of the present invention, and FIG. 2 is a downward blowing outer burner; and 3, a boiler furnace.

Due to the carbon-molecule gasification combustion technology, the prevention and control from the source, the element reduction, the scientific and radical treatment of pollution and the environmental protection and energy conservation of the whole process are realized; the cost is low, and the long-period operation is stable and reliable; various coals, biomasses and other organic matters (wastes) can be gasified and combusted; and the coal coke can be refined and the dust can be removed by a conversion function in the boiler according to the coal quality and the requirement.

Therefore, the invention has wide application range, almost all coal producing countries have markets, and almost all equipment using coal, oil, gas and electricity as fuel can be used. But also has great environmental protection benefit and economic benefit.

Claims

1. A carbon-molecule gasification combustion boiler power generation method is characterized by comprising the following steps:

firstly, adding coal with a desulfurizing agent, desulfurizing and gasifying the coal into clean coal gas in an improved molecular gasifier; the improved gasification furnace adopts a mechanism of complete oxidation reaction of a large-interface thin material layer designed in a molecular level coupled with a forward reduction reaction of a small-section thick material layer to produce gas by oxygen-deficient sulfur fixation; the gasification agent of the improved molecular gasification furnace is sprayed from the external grate (1-7) and the internal grate (1-8) at the bottom of the furnace, the raw material coal balls and granular coal with Ca/S close to 1 enter the furnace from the coal feeding port (1-3), the slag formed by sulfur fixation is discharged from the bottom of the furnace, and the coal gas is discharged from the coal gas port (1-4) at the top of the furnace; the improved molecular gasification furnace regulates and controls the steam of the annular steam jet hole (1-1) corresponding to the lower oxidation zone in time through the temperature change of the annular temperature measuring point (1-2) of the upper reduction zone, so as to ensure that the reaction in the furnace is stably carried out according to the design;

the lower part of the boiler is provided with a combustion chamber (6) with double functions of coal coke refining or dust removal, and the outer burner (2) is integrated with the boiler; closing an air valve of the outer burner (2) to enable the hot coal gas to play the inertia thrust effect to refine the coal coke; an air valve of the outer burner (2) can be opened and controlled at any time according to requirements, so that the air mixed hot gas is combusted for dust removal;

thirdly, the hot coal gas and the air with alpha close to 1 are mixed in a hearth of the boiler for clean combustion, so that the prevention and control from the source and the generation of harmful substances related to oxygen are realized; the high-temperature flue gas exchanges heat through a heating surface of the boiler and is discharged from a chimney after reaching the standard; the steam/hot water produced by the boiler drives a steam turbine to generate electricity/supply heat.

2. The method for generating power by a carbon-molecule gasification combustion boiler as set forth in claim 1, wherein the calcium-containing slag of the improved molecular gasification furnace is reused as a cement raw material.

3. A method for generating power by a carbon-molecule gasification combustion boiler according to claim 1, wherein the outer burners are arranged symmetrically at two or four sides, or at three or one side.

4. The power generation method of the carbon-molecule gasification combustion boiler as claimed in claim 1, wherein the improved molecule gasification furnace can be matched with a gas internal combustion engine and a gas turbine power generation system to produce required cold coal gas; but also can produce chemical raw material gas.

5. The power generation method of the carbon-molecule gasification combustion boiler according to any one of claims 1 to 4, which is based on the concept of energy environmental protection benefit:

Q_{practical coal energy}/(Q_{Total original energy of coal}+Q_{Total energy consumption of coal utilization process}) Maximum ═ maximum

(B_{Discharge of coal pollution}+B_{Total amount of pollution control discharge})/B_{Total amount of original pollutants of coal}Min ═ min

And (5) carrying out design and development.