CN1027234C - Sorbent for storing natural gas and method for making the same - Google Patents

Abstract

The invention relates to an adsorbent for storing natural gas and a manufacturing method thereof. This adsorbent has well-developed micropores and suitable pore size. The residue after lignite, candle coal, and wood hydrolysis——lignin is used as a raw material to prepare an adsorbent for storing natural gas. The adsorbent prepared by the present invention can absorb 17% to 24% (weight) of natural gas. Under a pressure of 6.0MPa, The amount of natural gas stored in the cylinder filled with adsorbent is equivalent to the amount of natural gas stored in an empty cylinder of the same volume under a pressure of 15 MPa. The manufacturing method of the adsorbent of the present invention is a chemical agent activation method. A mixed solution of alkali metal hydroxide and metal chloride is used as a chemical activation agent. The used chemical agent can be recycled after being regenerated by chemical method. The prepared adsorbent can be used to store natural gas as automobile fuel or domestic fuel, and can be used for storage and transportation of remote areas and natural gas that is not suitable for pipeline collection and transportation.

Description

The invention relates to an activated carbon substance and a manufacturing method thereof. The adsorbent for storing natural gas is a porous carbon substance, which belongs to a special-purpose activated carbon.

At present, there are high-pressure methods and liquefaction methods for storing natural gas, but these methods require large investment, high energy consumption, and are not safe. In order to overcome the above shortcomings, the present invention provides an adsorbent to store natural gas. Nowadays, adsorbents can be divided into two categories: non-porous and porous. Non-porous adsorbents have a small specific surface and are not suitable for gas adsorbents. Porous adsorbents have a large specific surface and are suitable for adsorption and separation of gas mixtures. These adsorbents mainly include activated carbon, silica gel, activated alumina, porous glass, etc. Its manufacturing process mostly adopts chemical agent activation method, such as US 3817874; US4082694 and US4642304, etc., all adopt single-component chemical agent (KOH) activation method to prepare powdery high specific surface activated carbon, which is suitable for water quality treatment agent, but not suitable for natural gas storage and is expensive.

The purpose of the present invention is to provide a new type of adsorbent which not only has a high specific surface for adsorbing natural gas, but also has a suitable pore structure for adsorbing natural gas, so that it not only has a large capacity for absorbing natural gas, but also has a fast desorption capacity. The invention adopts the method of regenerating and recycling multi-component chemical agents and activators to achieve the purpose of being economical and beneficial to industrial implementation.

以下;中孔直径不大于17 ，以满足对甲烷既具有较强的吸附能力，又具有快速的脱附能力。The present invention is achieved in that the natural gas adsorbent made from lignite, candle coal or lignin has well-developed micropores and suitable pore size distribution, and its micropore diameter is between 10

Below; the diameter of the middle hole is not more than 17 In order to meet the needs of both strong adsorption capacity and fast desorption capacity for methane.

The manufacture method of the natural gas adsorbent of the present invention is: the residue-lignin after lignite, candle coal, wood hydrolysis is used as raw material, carbonized several hours at 500～600 ℃, makes lignite, candle coal, lignin charcoal, After pulverization, the powdered carbon material with a diameter of less than 2 mm is soaked in a mixed solution of alkali metal hydroxide (such as KOH, NaOH) and metal chloride (such as ferric chloride, copper chloride) as a chemical activation agent. The ratio of KOH to NaOH can vary from 0 to 100%, but it is best to use a mixed solution. The amount of metal chloride is 0.1-5% (weight ratio) of the carbon material, and the activation ratio (that is, the activation The weight ratio of agent solution to carbon material) is 1:1～10:1. After soaking for several hours, put the soaked charcoal into the rotary activation furnace, and heat it to the activation temperature of 600-900°C under the atmosphere of inert gas (such as nitrogen). The activation time maintained at this temperature is 0.5-3 hours. Then let cool. The cooled sample was washed with water until pH = 7, and then dried at 100-120° C. for 2 hours to obtain a powdery natural gas adsorbent.

After adding suitable binder and water to the powdery adsorbent, it is kneaded and extruded in a extrusion molding machine. The caking agent can be carboxymethyl cellulose, polyvinyl alcohol or pulp waste liquid. Its dosage is 1-10% (by weight) of the powdered adsorbent. The amount of water is 50-300% (weight ratio) of the powdered adsorbent. The formed adsorbent is then dried at 100-120°C for several hours to obtain a granular natural gas adsorbent. When pulp waste liquid is used as the binder, no In addition, water is added in an amount of 100-300% (weight ratio) of the powdered adsorbent. The shaped samples are then subjected to carbonization treatment at 500-600°C to produce φ2-5mm granular natural gas adsorbents.

According to different purposes, powdery or granular natural gas adsorbents can be used. The adsorbent prepared by the present invention can absorb more than 17% (weight ratio) of natural gas, and the pressure of natural gas is 6.0MPa. The amount of stored natural gas is equivalent to the amount of natural gas stored in a container of the same volume that is not filled with adsorbent at a pressure of 15MPa. The natural gas stored in this way can be used for driving cars or as household fuel. Compared with gasoline, natural gas as a car fuel has the advantages of low price, high octane number, cleanness, and reduced wear and tear on car engines. Its CO ₂ Compared with fuel vehicles, the emission can be reduced by 30%, and the emission of CO can be reduced by 70%, which helps to reduce atmospheric pollution and alleviate the global greenhouse effect. In addition, natural gas adsorbents can also be used to store and transport natural gas in remote areas and scattered wells that are not suitable for pipeline collection and transportation.

Figure 1 is a flow chart of the manufacturing process of adsorbent for storing natural gas.

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Example 1: Candle coal was obtained by carbonizing candle coal at 500° C. for 2 hours. Take 100 parts of candle coal with KOH and contain a small amount of FeCl _solution as an activator. The ratio of activator to raw material is 4:1. Activated in a rotary activation furnace. The activation temperature is 700°C, and the activation time is 1.5 hours. After activation, the material is taken out and washed with water until neutral (PH=7). Under nitrogen atmosphere at 120°C, dry for 2 hours to obtain powdered natural gas adsorbent.

Example 2: Powdered lignin was carbonized at 550° C. for 2 hours to obtain charcoal. Get 100 parts of wood charcoal and mix with fresh activator and recycled activator. The fresh activator is a mixed solution of 50% KOH, 50% NaOH and a small amount of FeCl ₃ . The ratio of the amount of the solution to the amount of the raw material is 1:1. Activate in a rotary activation furnace, the activation temperature is 850°C, and the activation time is 1.5 hours. After activation, the material was taken out, washed with water until neutral (PH = 7), and dried at 120°C for 2 hours under _N2 atmosphere to obtain a powdery natural gas adsorbent.

Embodiment 3: Lignite was obtained by carbonizing lignite at 550° C. for 2 hours. Take 100 parts of lignite and use KOH and a solution containing a small amount of _FeCl3 as an activator. The ratio of its consumption to the amount of raw materials is 4:1. Activate in a rotary activation furnace, the activation temperature is 800°C, and the activation time is 1 hour. After taking it out, wash it with water until neutral (PH=7), and dry it in a nitrogen atmosphere at 120°C for 2 hours to make a powdery natural gas adsorbent.

Example 4: Take 100 parts of the powdered natural gas adsorbent prepared by lignin as the raw material under the optimal process conditions, add 1% polyvinyl alcohol (PVA) and 200 parts of water, knead evenly and place in a screw extruder forming. The shaped adsorbent was dried at 100°C in _N2 atmosphere for 2 hours to make a cylindrical granular adsorbent. The bulk specific gravity of the granular adsorbent is 0.27 g/cm ³ .

The performance of the adsorbent to adsorb natural gas was evaluated by gravimetric method and volumetric method respectively. The evaluation results are as follows: when the natural gas pressure is 5.0MPa, the amount of natural gas adsorbed by the adsorbent is 22% (weight ratio), and when the pressure is 6.0MPa, the amount of natural gas adsorbed by the adsorbent reaches 24% (weight ratio).

Assessed by the volume method, when the natural gas pressure is 5.0MPa, the amount of natural gas stored in the cylinder filled with adsorbent is equivalent to the amount of natural gas stored in an empty cylinder of the same volume under the pressure of 10.9MPa. The amount of natural gas stored in the steel cylinder is equivalent to the amount of natural gas stored in an empty cylinder of the same volume under a pressure of 15MPa.

Claims (6)

1, a kind of sorbent that is used for natural gas-storing is characterized in that having flourishing micropore, and its micro-pore diameter is 10

Below, median pore diameter is not more than 17

, be to soak in the activating agent promptly to make with the mixed solution of alkali metal hydroxide and metal chloride with carbonized material.

2, a kind of preparation of adsorbent method that is used for the natural gas-storing of claim 1 is characterized in that with brown coal, cannel coal or lignin be raw material, prepares by following step:

(A) under 500～600 ℃ with the raw material charing, obtain carbonized material;

(B) be to soak in the activating agent carbonized material with the mixed solution of alkali metal hydroxide and metal chloride, the chemical activation agent solution is 1: 1～10 with the ratio of charcoal material: 1(weight);

(C) be heated to 600～900 ℃ in the rotary furnace of the carbonized material that will soak under inert gas (as nitrogen) atmosphere, kept soak time 0.5～3 hour, then cooling;

(D) cooled charcoal material is washed with water, make PH=7, dry then, make the powdery natural gas adsorbent.

3, the preparation method of natural gas adsorbent for store according to claim 2 is characterized in that the powdered absorbent adding additives, and its consumption is 1～10%(weight ratio of powdered absorbent); Add water again, its consumption is 50%～300%(weight ratio of powdered absorbent), the moulding of in molding machine, kneading, and dry under 100～120 ℃, make granular natural gas adsorbent.

4,, it is characterized in that Bond is carboxymethyl cellulose, polyvinyl alcohol or spent pulping liquor according to the preparation method of claim 2 or 3 described natural gas adsorbent for store; When being Bond with spent pulping liquor, its consumption and powdered absorbent weight ratio are 100～300%.

5, the preparation method of natural gas adsorbent for store according to claim 2 is characterized in that alkali metal hydroxide is preferably KOH and NaOH mixed solution, and its ratio is in 0～100%(weight ratio).

6, the preparation method of natural gas adsorbent for store according to claim 2 is characterized in that metal chloride is FeCl ₃Or CuCl ₂, its consumption is 0.1～5%(weight ratio of charcoal material).