CN1194069C - A process and device for preparing liquid fuel from combustible solid waste - Google Patents

Abstract

The invention relates to a process and device for preparing liquid fuel from combustible solid waste. After collecting and sorting solid waste and household garbage to remove non-combustible components, they are purified, dried and crushed and then sent to a reaction kettle. In the presence of supercritical fluid, control the temperature and pressure to liquefy and convert it to obtain semi-finished liquid fuel and solid residues. The solid residues are then enriched, pressurized, and formed to obtain solid fuels. Semi-finished liquid fuels are obtained after refining. Finished liquid fuel. Using superheated tin to heat the reactor, the reaction speed is fast, the liquefaction yield is high, and the pyrolysis reaction can be suppressed and reduced, thereby reducing the common carbon deposition in the reaction, and the product is easily separated from the supercritical fluid.

Description

A process and device for preparing liquid fuel from combustible solid waste

(1) Technical Field: Solid Waste Recycling Treatment

(2) Background technology: With the continuous development of the world economy and the increasing population, the consumption of fossil fuels increases rapidly thereupon, while the reserves of fossil fuels are increasingly scarce. In order to solve the relationship between energy, environment and development well At present, the governments of various countries attach great importance to the development and research of new energy technologies for sustainable development.

my country is a large developing agricultural country with a large population. The annual output of agricultural and forestry combustible solid wastes such as crop straws and forestry processing wood chips reaches more than 600 million tons, some of which are directly burned as fuel, and some are burned by traditional biogas method and pyrolysis. The gasification method is used to prepare civil gas fuel, and most of the rest are not used. In addition, the annual output of combustible solid domestic waste in Chinese cities is nearly 100 million tons, and these combustible solid wastes are not well utilized. At present, there are mainly two methods of direct combustion and pyrolysis gasification for the treatment of forestry and agricultural combustible solid waste and combustible domestic waste. However, such treatment not only has low utilization efficiency of biomass, but also seriously pollutes the environment, and the pyrolysis and gasification process is complicated. How to make full use of these combustible solid wastes and turn them into treasures, especially how to turn them into high-quality renewable fuels, is a topic with profound practical significance. In recent years, scholars from various countries have carried out direct liquefaction technology from biomass, and made gratifying progress. Europe, the United States, Canada and other countries have developed biomass liquefaction technology with a yield of about 70%. We have carried out the research and development of new supercritical fluid liquefaction technology using combustible solid waste such as straw and other crop waste, forestry processing waste, and urban domestic waste as raw materials. When the temperature of the reaction system exceeds the critical temperature and the pressure exceeds the critical pressure, the fluid in the system is called supercritical fluid. Supercritical fluid liquefaction conversion refers to using supercritical fluid as a reaction medium to liquefy and convert other substances into useful substances in supercritical fluid.

(3) Contents of the invention:

1. The purpose of the present invention is to carry out supercritical processing of forestry and agricultural combustible solid waste (such as: forestry processing wood chips, crop straw, etc.) Fluid liquefaction conversion treatment to obtain small molecular organic compounds, such as: glucose, fructose, xylose, cellobiose, furfural, alkanes, paraffins, olefins, ethanol, terephthalic acid, benzoic acid, acetic acid, ethylene glycol, etc. .

2. Technical solution

1) Fig. 1 is a process flow diagram of the present invention. First, sort the raw materials (solid waste and domestic garbage) and remove the non-combustible components, purify them with pure water or dilute acetic acid solution to remove dust and other impurities, and dry them under certain pressure and temperature conditions , then pulverized, weighed and sent to the reactor with supercritical fluid according to the set ratio for liquefaction and conversion of supercritical fluid. After solid-liquid separation, semi-finished liquid fuel and solid residues are obtained. The solid residues are dried and weighed Sulfur-fixing agent, chlorine-fixing agent and binder are added to mix together, and then molded to obtain solid fuel, and the semi-finished liquid fuel is sent to the rectification tower for refining, and finally the finished liquid fuel is obtained.

2) Technical conditions

(1) The weight percentage concentration of the dilute acetic acid solution for purification treatment is 5-20%, the purification time is 10-100 minutes, and the addition amount and raw material weight ratio are 1-10: 1;

(2) The drying pressure is 0.08~0.1MPa, the temperature is 105±50℃, and the drying time is 4~40 hours;

(3) The crushing particle size is controlled at 30-100 mesh;

(4) The ratio of raw materials and supercritical fluid medium in the reactor is 1:5-30 (weight ratio), the temperature is 250-600 ° C, and the pressure is 6-40 MPa;

(5) The supercritical fluid is supercritical water, methanol, ethanol, toluene;

(6) The drying temperature of the solid residue is 40-100°C, the pressure is 0.07-0.1Mpa, and the drying time is 4-30 hours;

(7) Add 1-12% of sulfur-fixing agent, 1-10% of chlorine-fixing agent and 1-10% of binder to the dried solid residue according to the weight ratio, and form it under the pressure of 10-35MPa. The sulfur-fixing agent can be Ca(OH) ₂ , CaO, CaCO ₃ , etc., the chlorine-fixing agent can be Na ₂ CO ₃ , NaHCO _{3 ,} etc., and the binder can be organic binder, inorganic binder or calcium-based composite binder, etc. ;

(8) The rectification temperature of the semi-finished liquid fuel in the rectification tower is 100-500° C., and the pressure is 0.06-0.1 MPa. When the temperature is lower than 190°C, gasoline products are obtained, accounting for 38±8% of the total weight; when the temperature is 190-350°C, light fuel oil is obtained, accounting for 46±10%, and when the temperature is greater than 350°C, heavy oil products are obtained, accounting for 16% ±6%.

3) The best effect can be obtained by adopting the supercritical fluid conversion device as shown in Fig. 2 . It is composed of a reaction kettle 1, a fixing device 2, an electric furnace with a tin pool 3, a pool 4, a lifting device 5, a slide rail 6, a motor 7, and temperature measuring and pressure measuring wires 8. The reaction kettle is fixed on the lifting device. When working, it is immersed in an electric furnace with a tin pool to heat for supercritical fluid liquefaction transformation. The motor pulls the reaction kettle up and down through the pulley, and the elevator can carry the reaction kettle between the tin pool and the water pool. Mobile, electric furnace with tin pool is used to heat the reactor and the raw materials in it.

The reaction kettle is divided into two structures, A and B. The A structure is shown in Figure 3, which consists of a reaction cylinder 9, a gasket 10, a sealing head 11, a nut head 12, and a compression bolt 13. Type B structure is shown in FIG. 4 , which consists of a reaction cylinder 9 , a gasket 10 , a sealing head 11 , and a nut sealing head 12 .

3. The advantages and positive effects of the present invention

1) Fast response. After reaching the supercritical state, depending on different substances, it only takes 10 to 150 seconds (10 to 90 minutes for plastic liquefaction conversion) to liquefy and convert combustible solid waste into liquid fuel.

2) The liquefaction yield is high. Generally, the liquefaction yield can reach 80-95%.

3) No pollution. Since the reactor is closed, there is no secondary pollution.

4) Supercritical liquefaction conversion treatment can inhibit and alleviate the pyrolysis reaction, thereby reducing the common carbon deposition in the reaction.

5) Since superheated tin is used to heat the reaction kettle, and tin has a large heat storage capacity, the heating speed of the reaction kettle is fast, the heating is uniform, and the required temperature of the reaction kettle is also easy to control.

6) The product is easily separated from the supercritical fluid. Since most properties of supercritical fluid are a function of density, and its density can be controlled by adjusting the pressure, it is very convenient to control the pressure to control the solubility of organic matter, thereby separating the product from the supercritical fluid.

(4) Description of drawings:

Fig. 1 is a process flow diagram of the present invention. Figure 2 is a schematic diagram of the structure of the supercritical fluid liquefaction conversion process device. In the figure, 1 is a reaction kettle, 2 is a fixing device, 3 is an electric furnace with a tin pool, 4 is a water pool, 5 is a lifting device, 6 is a slide rail, The 7th is a motor, and the 8th is a temperature measuring and pressure measuring wire. Fig. 3 is a structural diagram of a type A reactor, and Fig. 4 is a structural diagram of a type B reactor, in which 9 is a reaction cylinder, 10 is a gasket, 11 is a sealing head, 12 is a nut head, and 13 is a compression bolt.

(5) Specific implementation methods:

Embodiment one (lignocellulosic substances)

First, the lignocellulosic substances in the combustible solid waste were sorted out and treated with purified water for 30 minutes. Then, it was dried at a temperature of 105° C. and a pressure of 0.095 MPa for 24 hours, and the water content was controlled within 10%. It is pulverized, and the particle size is controlled to exceed 60 meshes. Water is used as the supercritical fluid medium, and the weight ratio is lignocellulosic substances: water = 1:10, and the mixture is sent into the reactor. Then immerse the reactor in a tin pool at 420°C and observe the temperature controller. When the fluid temperature in the reactor reaches 374°C, take out the reactor after 15 seconds and put it into the pool for rapid cooling.

The product in the reactor is taken out for solid-liquid separation to obtain semi-finished liquid fuel and solid residue. After enriching the solid residue and drying it at 60° C. and 0.095 MPa for 10 hours, add 6% lime powder and 3% organic binder for mixing. Then the mixture is molded under a pressure of 15MPa to obtain solid fuel; the semi-finished liquid fuel is subjected to chromatographic analysis, which contains furfural, glucose, fructose, xylose, cellobiose, and L-glucose. The semi-finished liquid fuel is sent to a primary rectification tower with a temperature range of 100-300°C for refining to obtain light liquid fuel.

Embodiment two (waste and old plastics class)

First of all, the waste plastics in the combustible solid waste are selected and treated with 10% dilute acetic acid for 30 minutes. It was dried for 10 hours at a temperature of 85° C. and 0.09 MPa, and the moisture content was controlled within 6%. Then, it is pulverized, and the particle size is controlled at 50 meshes. With methanol as the supercritical fluid medium, it is sent into the reaction kettle by the weight ratio of plastics: methanol=1:15, and the weight percent concentration of methanol is 85～96%. . Then immerse the reactor in a tin bath at 350°C, and observe the temperature controller. When the fluid temperature in the reactor reaches 300°C, take out the reactor after 40 minutes, and put it into a water pool for rapid cooling.

The product in the reactor is taken out for solid-liquid separation to obtain semi-finished liquid fuel and solid residue. After enriching the solid residue and drying it at 70° C. and 0.09 MPa for 8 hours, add 8% lime powder + 5% soda powder and 5% organic binder for mixing. Then the mixture is molded under 20MPa to obtain solid fuel; the semi-finished liquid fuel is subjected to chromatographic analysis, which contains alkanes, olefins, ethylene glycol, benzoic acid, terephthalic acid, etc. The semi-finished liquid fuel is sent to a three-stage atmospheric rectification tower with a temperature range of 100-190°C, 190-350°C and 350-500°C for refining to obtain gasoline products, light fuel oil products and heavy oil products respectively .

Embodiment three (waste plastics class)

First of all, the waste plastics in the combustible solid waste are sorted out and treated with 15% dilute acetic acid for 50 minutes. It was dried for 15 hours at a temperature of 90° C. and 0.1 MPa, and the water content was controlled within 5%. Then, it is pulverized, and the particle size is controlled at 60 meshes. With toluene as the supercritical fluid medium, it is sent into the reactor by the weight ratio of plastics: toluene=1: 12, and the weight percent concentration of toluene is 80～97%. . Then immerse the reactor in a tin pool at 370°C and observe the temperature controller. When the temperature of the fluid in the reactor reaches 350°C, take out the reactor after 60 minutes and put it into the pool for rapid cooling.

The product in the reactor is taken out for solid-liquid separation to obtain semi-finished liquid fuel and solid residue. After enriching the solid residue and drying it at 65° C. and 0.095 MPa for 12 hours, add 10% lime powder + 5% soda powder and 5% organic binder for mixing. Then the mixture is molded at 25MPa to obtain solid fuel; the semi-finished liquid fuel is subjected to chromatographic analysis, which contains paraffins, olefins, ethanol, ethylene glycol, benzoic acid, terephthalic acid, etc. The semi-finished liquid fuel is sent to a three-stage atmospheric rectification tower with a temperature range of 100-190°C, 190-350°C and 350-500°C for refining to obtain gasoline products, light fuel oil products and heavy oil products respectively .

Claims (2)

1. A method for preparing liquid fuel from combustible solid waste, which is completed by the following steps: purify lignocellulosic solid waste with pure water for 30 minutes, and dry it for 24 hours at a temperature of 105°C and a pressure of 0.095MPa , control the water content within 10%, pass through 60 mesh through crushing, use water as the supercritical fluid medium, and put it into the reaction kettle after the ratio of 1:10 by weight ratio of lignocellulose and water, and carry out liquefaction conversion. The reaction kettle is immersed in a tin pool at 420°C. When the fluid temperature in the reaction kettle reaches 374°C, take out the reaction kettle from the tin pool after 15 seconds and put it in the water pool for rapid cooling, then take out the product in the reaction kettle for solid-liquid separation The semi-finished liquid fuel is sent to a primary rectification tower with a temperature of 100-300° C. to obtain a light liquid fuel after rectification. 2. The method for preparing liquid fuel from solid waste according to claim 1, characterized in that: the device used to complete the liquefaction conversion includes a reaction kettle (1), a fixing device (2), an electric furnace with a tin pool (3) , pool (4), lifting device (5), slide rail (6), motor (7), temperature measuring and pressure measuring wire (8) and pulley (14), the reaction kettle is fixed on the lifting device, and the electric furnace with tin pool And the water pool is under the slide rail, the motor pulls the reactor up and down through the pulley, the lifting device moves the reactor along the slide rail between the tin pool and the water pool, and the temperature and pressure measuring wires are connected to the reactor.

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