JPH07505116A - Sulfide removal method using catalytic carbon - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] name of invention Sulfide removal method using catalytic carbon field of invention The present invention is suitable for removing sulfides from gaseous or liquid media in the presence of oxygen and water. Relating to the use of highly catalytically active carbonaceous char.

Background of the invention Various methods are known for removing H2S using carbonaceous char.

For example, charcoal is known to have the ability to catalyze the oxidation of hydrogen sulfide. dampness active to remove hydrogen sulfide and various mercaptans from oxygen-containing gas streams Charcoal has been used. During the removal process, substances such as ammonia or hydroxide are added to the char surface. Improvement of carbonaceous char removal ability was achieved by adding base. came. Adding some type of halogen and/or transition metal impregnant to the carbonaceous char matrix Addition can increase the removal of hydrogen sulfide and mercaptans from humid air streams. It has also been found that However, sodium hydroxide, potassium iodide, or other Carbonaceous chips, which fundamentally contribute to the phenomena observed even in the absence of promoters such as compounds, None of the above improvements have changed the inherent properties of the camera.

Some improvements in the pore size distribution of activated carbon have been described, in which case high temperature activation Carbonaceous char is treated with urea or melamine compounds.

Calculate at high temperature. Char produced in this way has increased hydrogen sulfide adsorption capacity. However, the ability of this char to remove hydrogen sulfide by catalytic oxidation has not been tested or Oxidizing high-temperature activated carbon or coke, which has not been reported, Carbonaceous charcoal suitable for catalytic hydrogen sulfide oxidation, exposed to nitrogen-containing ammonium salts at The production of

The above prior art methods have certain drawbacks that limit their application.

If commercially available unimpregnated activated carbon is used for catalytic removal of hydrogen sulfide, The removal rate is low and therefore the hydrogen sulfide removal capacity is low. The above carbonaceous char exists The use of accelerators in the increases the cost and risk of ammonia dosing equipment and dosing control. . The use of sodium hydroxide and other metal salts also involves additional cost and The risk of thermal runaway increases due to a decrease in ignition temperature.

Therefore, two objects of the present invention are that when compared to other unimpregnated chars, sulfides and Apart from extrinsic parameters known to influence mercaptan removal. has catalytic activity in the removal of sulfides and mercaptans in the presence of oxygen and water. The aim is to provide a carbonaceous char. For example, particle size distribution as an extrinsic parameter , pore volume distribution, and contact time. Furthermore, it is an object of the present invention.

Producing and using the above carbonaceous char with minimal cost and risk when compared to conventional techniques. It is to be.

Summary of the invention Generally, the present invention provides a method for catalyzing a carbonaceous char into a medium containing oxygen and water. The process consists of removing sulfides and mercaptans. These chars are rich and poor Produced by low-temperature carbonization and oxidation of raw materials (raw materials with low nitrogen content). One The low-temperature char, which has been oxidized by In all cases where high temperature carbonaceous char is exposed to chemical compounds, it must be heat treated at temperatures above 700°C. It was manufactured by Low-temperature carbonaceous char experiences temperatures of over 700℃. It is something that has not been done yet.

Preferred rich-poor feedstocks are bituminous coal or various chemical treatments to produce high-grade or low-grade bitumen 1 such as materials derived from coal or lignocellulosic materials It is a bituminous vertical-like material. High-grade coal includes anthracite or semi-anthracite; Examples of low-grade coal include peat, lignite, and subbituminous coal. conversion of these raw materials Examples of chemical treatments include alkali metal treatment for high-grade materials, zinc chloride or This type of treatment, including phosphoric acid treatment, can also be applied to lignocellulosic materials.

In a preferred embodiment of the invention, the raw material is finely ground and, if necessary, pitted. Mixed with a small amount of a suitable binder such as Shape and size. This sized material is then heated to a temperature below 700°C, preferably 400°C. Oxidizes greatly at temperatures below °C. It is now clear that further catalytic activity of the final product can be obtained. Continue oxidizing until it is no longer reliable. This oxidation removes the coking properties of bituminous coal. yields an optimally oxidized char well beyond that typically required for oxidation. Out Other convenient oxidation methods can also be used to achieve low temperature oxidation and carbonization of the emitting material. Ru.

The oxidized low-temperature carbonaceous char is then heated, but not after initial calcination and condensation of the carbon structure. During its calcination and condensation, cheap, plentiful and relatively non-toxic substances such as urea are used. exposure to small amounts of nitrogen-containing compounds; the amount of nitrogen-containing compounds used is typically small. , preferably less than 5% by weight of the oxidized low temperature carbonaceous char, or the catalytic content of the final product. The amount is such that further acquisition of medium activity is no longer possible tomorrow. Oxidized low temperature char heating to an elevated temperature, preferably 850-950°C in the presence of a nitrogen-containing compound; Attributable to char and/or nitrogen-containing compounds, which carry out the above treatment by This heating is preferably carried out in an otherwise inert atmosphere apart from gases and steam; The heating rate and temperature are such that further gain of catalytic activity in the final product is no longer evident. It is preferable to choose sea urchin.

Nitrogen-treated high-temperature carbonaceous char is added or doped with other gasifying agents such as air. the desired temperature in water vapor and/or carbon dioxide at temperatures above 700°C without adding Can be activated to density. The calcined or calcined/activated carbonaceous char is then heated with acid. below 400°C, preferably below 200°C in a free or inert atmosphere Cool to temperature. Exposure to oxidation/nitrogen-containing compounds/calcination or calcination for desired number of times. Further catalytic activity can be achieved by repeating calcination/activation/cooling in an inert atmosphere. It is possible to achieve a certain amount of acquisition. On the other hand, in order to further increase the catalytic activity, high-temperature carbonaceous char Other known methods of developing catalytic activity can be applied to the product.

The catalytically activated carbonaceous char produced by the above method is then treated in the presence of water and oxygen. contact with a sulfide-containing medium below. tli compounds are mainly based on the sulfuric acid field name and elemental sulfuric acid. It is removed from the medium by catalytic oxidation to yellow. The operating temperature is about 0-300℃, preferably Preferably, the temperature is about 0 to 100°C, more preferably about 25 to 90°C.

Currently preferred embodiment The usefulness of the present invention is illustrated by the following two examples. In each example, the particle size effect is disabled. Equal mesh size fractions of carbonaceous char were evaluated in order to these fruits The chars used in the examples have nearly identical density and CCiz4 activity. Most of this Almost equal means that the pore volumes of both chars are almost equal. Therefore, sulfur Since the extrinsic properties that affect chemical removal are almost the same in these samples, the present invention The advantages of light are obvious. Example 1 shows the H of a specific mesh size fraction of commercially available activated carbon. Example 2 shows the 2S removal ability, and Example 2 shows the H,S removal ability of the present invention. The comparison shows that the performance of the present invention is significantly superior to that of typical activated carbon. Karu.

Example 1 Commercially available activated carbon, BPL (Calgon Carbon Cor) poration, made by Bipperg PA), 6 mesh smaller than 5 mesh. The granules were sized into pieces larger than U.S. standard sieves. When granulated in this way, This carbon has an apparent density of 0.504 g/cc (Test method TM-7, Calgon C arbon Corporation, Pittsburgh PA) g and 55.1 % CCQ4 number (Test method TM-6, Calgon Carbon Corporation tion, Pittsburgh, PA) at a bed depth of 9 inches. The column was packed with an internal diameter of 0.73 inch to provide a uniformity.

Force ram filling was carried out in such a way as to achieve a packing density equal to the apparent density. phase Known relative humidity of 50% or more, oxygen content of 17 v/v% or more, approximately lv/v% A gas stream with a Has concentration was generated at a flow rate of 1450 ± 20 cc/min under normal conditions. passed through the column. The effluent from this column was monitored to ensure a 50 ppm H2S throughflow. The elapsed time required to achieve this was measured. For this carbon sample, the elapsed time was 9 minutes. there were.

Example 2 Bituminous coal is finely ground and mixed with about 4-6% coal tar pitch to create briquette ink. did. The produced briquettes are crushed and divided into 5 pieces, and the size is smaller than 4 mesh and 10 mesh. A sieve having a size larger than the sieve size (American standard series sieve) was obtained. Presence of large amounts of excess air At present, this material was heated from 100°C to 200°C at a rate of 200°C/h at Zoo°C/ Heating from 200°C to 350°C at a rate of h, then kept at 350°C for 4h, and finally Oxidation was carried out by heating from 350°C to 450°C at a rate of 100°C/h. profit The oxidized material is cooled to about room temperature in a low oxygen content atmosphere and sized into approximately 5 sized particles. A material smaller than 6 meshes and larger than 6 meshes (US standard series sieves) was obtained, and then It was impregnated with an aqueous urea solution and dried. The amount of urea solution used is urea on a dry weight basis. This was sufficient to obtain 4% impregnation. After impregnation, the oxidized and impregnated low temperature char A portion was rapidly heated to 950° C. under an inert gas atmosphere. Immediately after this calcination treatment , the product material is activated with steam at 950° C. for a period sufficient to achieve the desired yield. Ta. After activation, the material was cooled to ambient temperature under an inert gas atmosphere. Catalytic activity produced in this way The activated carbonaceous char is collected in smaller than 5 meshes and larger than 6 meshes. When sized to size 1 (U.S. standard sieve), 0.495g/cc Apparent density (Test method TM-7, Calgon Carbon Corpora tion, Pittsburgh, PA) CCQ of 1-minute grains and collected char 4 counts It was 55.5%.

The H2S removal ability of the activated high-temperature carbonaceous char with catalytically active granules prepared above is , IA was measured using the same conditions as in Example 1. This activated carbonaceous char with catalytic activity In the sample, the elapsed time required to achieve 50 ppm H25 flow through was 326 minutes. there were.

Having described the presently preferred embodiments of the invention, the present invention (within the scope of the claims) It can be embodied in other ways.

Claims (6)

[Claims] 1. A gaseous or liquid medium is contacted with a catalytically activated carbonaceous char in the presence of oxygen and water. In the method for removing sulfides from the medium, the char is produced from bituminous coal or bituminous coal-like material carbonized and oxidized at temperatures below 0°C; It was then exposed to nitrogen-containing compounds during initial exposure to temperatures above 700°C. This is the above removal method. 2. The catalytically activated carbonaceous char contains at least water vapor, carbon dioxide, and oxygen. 2. The method according to claim 1, wherein the method is activated at a temperature of 700° C. or higher. 3. A method according to claim 1, wherein said sulfide is hydrogen sulfide. 4. 2. The method of claim 1, wherein said process is carried out at a temperature of 0 to 300<0>C to remove said sulfides. Method. 5. 2. The method of claim 1, wherein said method is carried out at a temperature of about 25 to 90<0>C to remove said sulfides. the method of. 6. 2. The method of claim 1, wherein said nitrogen-containing compounds are urea and urea-like compounds.