CN106398727B

CN106398727B - Heating device for garbage carbonization

Info

Publication number: CN106398727B
Application number: CN201610925710.4A
Authority: CN
Inventors: 韩先福; 王红军; 贺伟力
Original assignee: 刘艳
Current assignee: Beijing qihonglan Environmental Protection Technology Co.,Ltd.
Priority date: 2016-10-31
Filing date: 2016-10-31
Publication date: 2020-04-10
Anticipated expiration: 2036-10-31
Also published as: CN106398727A

Abstract

The invention provides a heating device for carbonizing garbage, and a heating chamber of the heating device is respectively provided with at least one steam inlet on two opposite side walls. The heating furnace can reduce the generation of coking on the inner wall of the heating chamber.

Description

Heating device for garbage carbonization

Technical Field

The invention belongs to the technical field of heating devices, and particularly relates to a heating device for pyrolysis and carbonization of household garbage.

Background

At present, the annual output of municipal domestic waste in China reaches 1.8 hundred million tons, the annual output of municipal per capita waste is about 440 kilograms, and the annual output of municipal domestic waste is rapidly increased by more than 10 percent every year, and the annual output of municipal domestic waste in China reaches 4.09 million tons in 2030 years. The per capita garbage generation amount of large and medium cities, particularly extra large cities, is relatively high, and the growth rate reaches about 20%.

If the garbage cannot be properly treated and disposed of, toxic and harmful substances (heavy metals, pathogenic microorganisms, etc.) in the garbage can enter the ecological system through certain environmental media such as soil, atmosphere, surface or underground water and cause pollution. This not only destroys the ecological environment, leading to irreversible ecological changes, but also poses a hazard to animal and plant safety and human health.

At present, the garbage disposal can only reduce the garbage capacity through incineration disposal. The incineration treatment method can generate various pollutants harmful to the environment, such as dioxin, and the like, the safe garbage incineration treatment equipment has high price and large investment scale, the incineration treatment can only be maintained through treatment cost, generally, resin and plastic in the garbage account for about 10 percent, and the rest is kitchen, paper, wood chips, and the like.

CN104263388A discloses a garbage carbonization reaction system, which comprises a reaction kettle, a reaction tank, a steam generator and a control device, wherein the steam generator is connected to the reaction kettle, and is used for providing steam to the reaction kettle; the reaction tank is used for placing garbage, and when the reaction is carried out, the reaction tank is pushed into the reaction kettle to react to generate a carbonized mixture; and when the reaction is finished, pulling the reaction box out of the reaction kettle.

CN102304372A discloses a superheated steam carbonization furnace for treating organic garbage, which comprises a superheated steam generator, an organic garbage carbonization furnace, a steam turbine generator, a gas-liquid separator, and a gas-liquid separator.

CN102606236A discloses a built-in steam tubular refuse treatment cogeneration system, including waste gasification stove and turbine steam power generation facility, wherein, turbine steam power generation facility connects gradually its characterized in that including steam generator, steam discharge pipe, steam package, steam turbine and generator: the steam generator is arranged in the garbage gasification furnace; the steam generator is a cylindrical cage-shaped structure consisting of an upper annular pipe, a plurality of straight pipes and a lower annular pipe, and two ends of each straight pipe are respectively communicated with the upper annular pipe and the lower annular pipe; the upper annular pipe is communicated with one end of the steam discharge pipe, the other end of the steam discharge pipe is communicated with the steam bag, and the lower annular pipe is communicated with a water inlet pipe.

CN104976621A discloses a household garbage pyrolysis gasifier, the furnace body comprises an incinerator outer shell, a refractory brick layer and an incinerator inner container from outside to inside; the bottom of the furnace body is provided with a slag discharging component and a water sealing component; it is characterized in that the upper part of the furnace body is provided with an air inlet and a combustible gas outlet; the bottom of the furnace body is provided with a steam inlet; the top of the furnace body is provided with a steam outlet; a hollow interlayer is arranged between the refractory brick layer and the inner container of the incinerator; the bottom of the interlayer is communicated with the bottom in the furnace body, and the upper part of the interlayer is communicated with a combustible gas outlet; an air inlet channel is arranged in the interlayer, the upper part of the air inlet channel is communicated with an air inlet arranged at the upper part of the furnace body, and the lower part of the air inlet channel is communicated with the inner bottom of the furnace body.

CN204325273U discloses a garbage plasma gasification furnace using water vapor as a gasification medium, which comprises a garbage gasification chamber at the upper part and a high-temperature water vapor generation chamber at the lower part, wherein water-cooling furnace arches are arranged at intervals between the garbage gasification chamber and the high-temperature water vapor generation chamber, and the water-cooling furnace arches separate the garbage gasification chamber from the high-temperature water vapor generation chamber; two plasma torches are circumferentially arranged on the inner wall of the high-temperature water vapor generation chamber, and low-temperature water vapor is used as working gas of the plasma torches.

CN102746903A discloses a method for dividing a domestic garbage dry distillation-gasification furnace into a plurality of standard dry distillation treatment units, and combining the units into a large-scale domestic garbage dry distillation-gasification furnace according to the requirements of different treatment capacities, wherein the standard dry distillation treatment units are cubic furnace bodies, and the dry distillation treatment units are arranged above the unitsA drying section and a carbonization section, wherein the garbage is firstly carbonized in an anaerobic state to decompose carbonization coal gas and carbide residues, the carbide is burnt in a lower burning layer to generate high temperature, water vapor and air are used as gasifying agents, and the carbide in a high-temperature state of a reduction layer combusts CO generated by the burning₂Reducing with steam to generate gasified coal gas without generating dioxin; the high-temperature gasification coal gas heats and distills the garbage in the garbage distillation section in the rising process, the garbage in the drying section is dried by continuously rising, organic matters in the garbage are converted into clean fuel gas, and the carbonization coal gas and the gasification coal gas are collected for utilization, so that the dioxin-free and waste gas-free discharge is realized.

WO2011/000513a1 discloses an integrated waste treatment system and method comprising the use of a source of combustible waste, a separator for separating the combustible waste from recyclable materials, a vacuum dryer for drying the combustible waste to produce a pyrolysis feedstock and a pyrolyzer for pyrolyzing the pyrolysis feedstock to produce char and pyrolysis gases.

GB2006/002409A discloses a method for treating waste, the method comprising: (i) (ii) either (a) a gasification step comprising treating the waste in a gasification unit in the presence of oxygen and steam to produce off-gas and char, or (b) a pyrolysis step comprising treating the waste in a pyrolysis unit to produce off-gas and char; and (ii) a plasma treatment step comprising plasma treating the exhaust gas and char in a plasma treatment unit in the presence of oxygen and optionally in the presence of steam.

In the 'resource treatment mode of shallow separation urban domestic garbage', chapter, China municipal engineering, 6 months in 2013, stage 3 (total 166), 53-55, the gradual transition of the treatment of the urban domestic garbage from the traditional landfill, incineration and biochemical treatment modes to the recycling economy and resource treatment is introduced, the project construction of a closed low-temperature carbonization treatment and organic solid waste treatment plant of the domestic garbage is introduced, the closed internal circulation low-temperature carbonization technology of the domestic garbage is indicated to be a thermochemical processing method of solid biomass, the process produces high-heat value gaseous fuel, the resource degree of the technology is higher, and part of garbage percolate and spray water can reach the standard and be discharged after biochemical treatment.

In the above documents and other prior arts, coking is severe in the case of the carbonizing device after a certain period of use, which seriously affects the continuous operation of the equipment.

Disclosure of Invention

In order to solve the problems, the inventor of the invention fully combines the carbonization process of the municipal solid waste and the principle of coking generation through deep and systematic research, carries out comprehensive research in the whole process of the waste treatment, provides the following technology, and effectively reduces the coking generation.

In one aspect of the invention, there is provided a heating apparatus for charring waste, the heating chamber of the heating apparatus being provided with at least one steam inlet in each of two opposite side walls.

Preferably, the steam inlet is slit-shaped.

Preferably, the length of the steam inlet (i.e. the slit length) is at least 1/3 of the heating chamber side wall height. This length ensures that the steam has a sufficiently large impingement purge range within the heating chamber.

More preferably, the steam inlets provided on the two sidewalls are oppositely disposed.

In production, it is found that when top-blown superheated steam is used, i.e. steam is introduced through the top of the heating chamber, after the heating device is used for a period of time, coking is easily generated in the heating chamber, especially on the inner wall of the top of the inner wall, and the coking can affect the extraction of product gas material flow and seriously affect the production. To this end, the present inventors have conducted extensive studies using a side-opposed slit-type steam inlet. When the superheated steam is fed through the steam inlets which are arranged oppositely, the opposite collision is generated, so that the lateral flow along the wall of the heating chamber is generated, the bio-oil substances can be effectively prevented from being accumulated on the upper wall in the heating chamber, and the generation of coking is effectively avoided.

The steam inlet is preferably provided with a gas flow distribution plate consisting of perforated plates.

In a preferred embodiment, the interior of the heating chamber is provided with a liner.

More preferably, the lining is of a four-layer structure, the lining closest to the outer shell of the heating chamber is taken as a first layer, the lining farthest from the outer shell of the heating chamber is taken as a fourth layer, and the first layer, the second layer, the third layer and the fourth layer are sequentially arranged from outside to inside, wherein the first layer is an alumina silicate fiber brick (the thickness of the alumina silicate fiber brick is preferably 5-50mm), the second layer is a general alumina refractory fiber felt (the thickness of the alumina refractory fiber felt is preferably 5-10mm), the third layer is a high alumina refractory fiber felt (the thickness of the alumina refractory fiber felt is preferably 5-10mm), and the fourth layer is a zirconium-containing refractory fiber felt (the thickness of the zirconium-.

The composite lining has a good heat preservation effect, can resist the impact of high-temperature hot steam, obviously reduces the heat dissipation loss and the exhaust loss, improves the effective heat load, improves the heat efficiency from 84.3 percent to 91.2 percent, and has a remarkable energy-saving effect. Moreover, the lining with the structure is not easy to fall off.

In another aspect of the invention there is provided a method of charring waste using the heating device described above, the method comprising passing a conveyor containing waste through a heating chamber of the heating device to obtain combustible and char material.

The temperature of the high-temperature oxygen-free steam in the heating chamber may be 300-600 ℃.

The garbage is preferably municipal domestic garbage.

In the process of the invention, a gas stream comprising bio-oil may be withdrawn from the top of the heating chamber.

More preferably, the method for carbonizing the garbage by using the heating device comprises the following steps: (1) loading the refuse into a refuse conveyor; (2) making the garbage conveying device pass through a high-temperature distillation carbonization device; (3) taking out a gas stream from the upper part of the high-temperature distillation carbonization device; (4) passing the gas stream in gaseous form through a catalyst bed; (5) condensing and separating the effluent from the catalyst bed to obtain liquid combustible and water; (6) obtaining the carbon substances from the garbage conveying device passing through the high-temperature distillation carbonization device.

The temperature of the high-temperature oxygen-free steam is preferably 300-. The pressure of the high-temperature oxygen-free steam is preferably 0.2-1.0 MPa.

Preferably, wherein the high temperature oxygen-free steam comprises nitrogen. More preferably, the nitrogen content is 10-80 v.%, more preferably 20-60 v.%.

In the present invention, it is preferred that the waste is not subjected to any pretreatment.

Compared with the simple dry distillation in the prior art, the nitrogen gas can prevent the garbage from burning in the carbonization process, so that the generated carbon has higher heat value. In addition, compared with pure steam gasification in the prior art, the existence of nitrogen can also increase the heating medium heat value, improve the heating efficiency and thus improve the carbonization efficiency, and can also save the steam consumption, and more importantly, through the addition of nitrogen, can provide the required catalytic conditions for the subsequent catalytic upgrading of distillate, such as adjusting the required steam partial pressure, because the excessive steam pressure can cause the catalytic upgrading to be difficult to be effectively carried out, and the addition of nitrogen can reduce the steam partial pressure in the gas stream, namely the distillate.

The inventor finds that in the existing garbage steam treatment technology, selective steam treatment conditions for garbage composition are often ignored, and the difference of the garbage composition is ignored, so that the garbage treatment efficiency is low. The inventor of the invention has conducted a great deal of research, and selects different steam treatment conditions according to different garbage compositions, thereby obtaining good steam treatment effect. In particular, the following conditions of the high-temperature distillation carbonization treatment are selected: (1) when the content of the organic substances in the garbage is more than or equal to 80 weight percent based on the total weight of the garbage, the temperature of the high-temperature oxygen-free steam is 300-450 ℃, and preferably 320-400 ℃; the nitrogen content in the high temperature oxygen-free steam is 10-30 v.%, preferably 10-20 v.%; the retention time in the high-temperature distillation carbonization device is 8-12 h; and (2) when the content of organic substances in the garbage composition is less than 80 wt% based on the total weight of the garbage, the temperature of the high-temperature oxygen-free steam is 450-600 ℃, preferably 500-550 ℃; the nitrogen content in the high temperature oxygen-free steam is 40-80 v.%, preferably 60-80 v.%; the retention time in the high-temperature distillation carbonization device is 5-8 h.

When the content of organic substances in the garbage is higher, the steam treatment condition is particularly favorable for generating liquid combustible substances; and when the content of the organic substances is lower, the production of the carbon substances is particularly favorable.

In a preferred embodiment, the catalyst in the catalyst bed is an inorganic oxide or silicate supported iron based catalyst, or a carbon supported iron based catalyst, or a mixture of both.

In a particularly preferred embodiment of the present invention, the present inventors have conducted extensive studies to develop a catalyst which is effective in the hydro-upgrading of bio-oil in a gas stream withdrawn from the upper part of a high temperature distillation carbonization apparatus, and which may be a catalyst represented by the following formula: Ni-Cu-Pd-Co₂O₃-Fe₂O₃/SiO₂Wherein the molar ratio of Ni, Cu, Pd, Co and Fe is (1-2): 5-10): 0.1-0.5): 1-2): 10-20, based on the total weight of the catalyst, Ni-Cu-Pd-Co₂O₃-Fe₂O₃The content of active ingredient is 1-8%, preferably 2-5%, more preferably 3%. SiO 2₂Is a carrier.

The composition of bio-oils is generally complex and can include mainly acids, aldehydes, ketones, alcohols, phenols, furans, esters, ethers and small amounts of nitrogen-containing compounds as well as other multifunctional compounds. Because of the characteristics of poor thermal stability, strong acidity and corrosivity, high water content, low calorific value, difficulty in mutual solubility with petroleum-based products and the like, the bio-oil can only realize primary application, such as being used for thermodynamic equipment such as industrial kilns and oil-fired boilers and the like, cannot replace petroleum products to be directly applied to combustion of internal combustion engines or turbines, and cannot meet the modern high-grade industrial application. In order to improve the applicability of the bio-oil, the bio-oil needs to be converted into high-grade liquid fuel to meet the requirement of transportation fuel so as to realize replacement or partial replacement of petroleum products, and therefore the bio-oil needs to be modified and upgraded to convert chemical components of the bio-oil from hydrocarbon oxides into hydrocarbons. One of the keys to how to effectively upgrade bio-oil is the development of catalysts.

It was found that, in the above-mentioned catalyst of the present invention, Ni^δ+Mo more conventional than^δ+The catalyst has higher activity, the use of Ni can obtain C6-C12 hydrocarbon (preferably alkane) with high selectivity, the use of Cu can obtain C16 hydrocarbon (preferably alkane) with high selectivity, and the simultaneous use of Ni and Cu is surprisingly found to ensure that certain amount of C18 and C19 hydrocarbon can be obtained, and the use of Ni and Cu on the surface can enable C-O bond in the bio-oil to effectively generate hydrogenolysis reaction.

Unlike typical biomass oil upgrading, the gas stream of the present invention contains a higher proportion of steam and therefore places very high demands on the hydrothermal stability of the catalyst. Conventional catalysts used for biomass oil upgrading cannot be used for the upgrading of the gas stream of the present invention. The iron catalyst is a common catalyst for removing oxygen in plant-based materials, however, the iron catalyst fails when meeting water, while the palladium catalyst is effective when meeting water, but the oxygen removing effect is not good and expensive, and a very small amount of palladium is added into iron, so that a good synergistic effect can be obtained. The inventor researches and discovers that the addition of a small amount of palladium is helpful for covering the surface of iron in the catalyst with hydrogen, so that the reaction is accelerated, the water blocking reaction is prevented, the hydrogen consumption is low, the activity, the stability and the selectivity of the catalyst are far better than those of a single iron catalyst, and the catalytic life of the catalyst can be prolonged by more than 2 times.

The inventor of the invention also finds that the addition of Co is beneficial to reducing the grain size of the catalytic active component, is beneficial to the dispersion of the catalytic active component and reduces the aggregation, and has very positive significance for improving the activity, selectivity and stability of the catalytic active component. However, if the amount of Co is too large, Co covers the hydrogenation active centers Ni, Cu, etc., thereby reducing the activity of the catalyst.

The above-mentioned particularly preferred catalysts have not been reported in the prior literature, and it is specifically designed according to the specific composition characteristics of the gas stream and bio-oil recovered from the waste, and a good upgrading effect is achieved.

The catalyst can be prepared by adopting an impregnation calcining method which is conventional in the field. Specifically, a certain amount of precursor salt such as Ni (NO) is weighed according to the proportion₃)₂、Cu(NO₃)₂、Pd(NO₃)₂、Co(NO₃)₂、Fe(NO₃)₃(or their hydrate forms) and citric acid, adding deionized water to dissolve, stirring uniformly to prepare a solution with the concentration of 0.5-1.5mol/L, weighing a certain amount of silicon dioxide, putting the silicon dioxide into a reaction container, pouring the prepared solution into the reaction container, heating the solution in a constant-temperature heating oil bath device with a stirrer, stirring the solution at the temperature of 60-120 ℃ for 1H-10H, then putting the solution into a drying box to dry the solution at the temperature of 100-150 ℃ for 12H, then putting the obtained catalyst precursor into a muffle furnace to calcine the catalyst precursor for 1H-6H at the temperature of 500-800 ℃, and then calcining the catalyst precursor in H₂Reducing and activating at 200-300 ℃ in the presence of the catalyst to prepare Ni-Cu-Pd-Co₂O₃-Fe₂O₃/SiO₂A catalyst.

For the purposes of the present invention, the gas stream is preferably substantially free of dioxins. Because the temperature is raised and the distillation is carried out under the anaerobic condition, harmful substances such as dioxin and the like are not generated, and the atmospheric environment can be protected. This has a great advantage over the conventional incineration method.

Preferably, wherein the high temperature oxygen-free steam used in the high temperature distillation carbonization unit is from a high pressure once-through steam furnace.

In another aspect of the invention, there is provided a liquid combustible obtained according to the aforementioned process. Preferably, the oxygen content in the liquid combustible is less than 10 wt%, preferably less than 5 wt%, more preferably less than 2 wt%. Further, the liquid combustible has a higher calorific value of greater than 40 MJ/kg.

In another aspect of the invention, there is provided a carbonaceous material obtained by a process according to any one of the preceding claims.

Preferably, the carbonaceous material is coke. Preferably, the carbonaceous material is semicoke.

Drawings

FIG. 1 is a top plan view of a high temperature distillation carbonization apparatus according to the present invention;

wherein 1 denotes a side wall of a heating chamber of the heating device, 2 denotes a steam inlet, and 3 denotes a conveyor;

detailed description of the preferred embodiments

The present invention will be described in further detail below with reference to the following examples and comparative examples, but the embodiments of the present invention are not limited thereto.

Example 1

Selecting domestic garbage from a garbage compression transfer station in the Haisheu area of Beijing, and detecting the composition of the garbage as shown in the following table 1:

table 1: urban domestic garbage component composition

The garbage is subjected to high-temperature distillation carbonization through the following steps: (1) loading the refuse into a refuse conveyor; (2) making the garbage conveying device pass through a high-temperature distillation carbonization device; (3) taking out a gas stream from the upper part of the high-temperature distillation carbonization device; (4) passing the gas stream in gaseous form through a catalyst bed; (5) condensing and separating the effluent from the catalyst bed to obtain liquid combustible and water; (6) obtaining the carbon substances from the garbage conveying device passing through the high-temperature distillation carbonization device. The high-temperature distillation carbonization device is heated by high-temperature oxygen-free steam, the temperature of the high-temperature oxygen-free steam is 355 ℃, the content of nitrogen in the high-temperature oxygen-free steam is 12 v.%, and the average treatment time is 9.0 hours. The inside lining of heating chamber is the four-layer structure, uses the lining that is closest to the heating chamber shell as the first layer, uses the lining that is furthest away from the heating chamber shell as the fourth layer, is first layer, second floor, third layer and fourth layer in proper order, and the first layer is the alumina silicate fiber brick, and thickness is 20mm, and the second floor is general aluminium refractory fiber felt, and thickness is 10mm, and the third layer is high aluminium refractory fiber felt, and thickness is 10mm, and the fourth layer is the refractory fiber felt that contains zirconium, and thickness is 5 mm.

The operating cycle of the heating device was 60 days before the decoking process required to be shut down.

Comparative example 1

This comparative example differs from example 1 only in that the heating chamber is lined with ordinary heat-resistant bricks (thickness 20mm) and a composite single-layer high-alumina refractory fiber felt (thickness 10 mm). The operating cycle of the heating device was 10 days before the decoking treatment required to be shut down.

It is clear from the above examples and comparative examples that the degree of coking in the apparatus of the present invention is greatly reduced during use, thereby greatly improving the stability and economy of operation of the apparatus.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. All citations referred to herein are incorporated herein by reference to the extent that no inconsistency is made.

Claims

1. A method for carbonizing garbage by using a heating device, wherein the heating device is a high-temperature distillation carbonization device, a heating chamber of the heating device is respectively provided with at least one steam inlet on two opposite side walls, a lining is arranged inside the heating chamber and has a four-layer structure, the lining closest to the outer shell of the heating chamber is taken as a first layer, the lining farthest away from the outer shell of the heating chamber is taken as a fourth layer, and the first layer, the second layer, the third layer and the fourth layer are sequentially arranged from outside to inside, the first layer is an alumina silicate fiber brick and has the thickness of 5-50mm, the second layer is a common aluminum refractory fiber felt and has the thickness of 5-10mm, the third layer is a high-aluminum refractory fiber felt and has the thickness of 5-10mm, and the fourth layer is a zirconium-containing refractory fiber felt and has the thickness of 2-8 mm;

wherein the temperature of the high-temperature oxygen-free steam in the heating chamber is 300-600 ℃;

the method comprises the following steps: (1) loading the refuse into a refuse conveyor; (2) making the garbage conveying device pass through a high-temperature distillation carbonization device; (3) taking out a gas stream from the upper part of the high-temperature distillation carbonization device; (4) passing the gas stream in gaseous form through a catalyst bed; (5) condensing and separating the effluent from the catalyst bed to obtain liquid combustible and water; (6) from wearingObtaining carbon substances by a garbage conveying device of the high-temperature distillation carbonization device; the catalyst of the catalyst bed is a catalyst of the formula: Ni-Cu-Pd-Co₂O₃-Fe₂O₃/SiO₂Wherein the molar ratio of Ni, Cu, Pd, Co and Fe is (1-2): 5-10): 0.1-0.5): 1-2): 10-20, based on the total weight of the catalyst, Ni-Cu-Pd-Co₂O₃-Fe₂O₃The content of active ingredients is 1-8%.

2. The method of claim 1, wherein the steam inlet of the heating device is slit-shaped.

3. The method of claim 2, wherein the length of the steam inlet of the heating device is at least 1/3 the heating chamber sidewall height.

4. A method according to claim 1 or 2, wherein the steam inlets provided on the two side walls are oppositely arranged.

5. The method of claim 4, wherein the steam inlet is provided with a gas flow distribution plate consisting of a perforated plate.

6. A process according to claim 1 or 2, wherein the waste is municipal domestic waste.

7. A process according to claim 1 or 2, wherein a gas stream comprising bio-oil is withdrawn from the top of the heating chamber.