MXPA06007046A - Regenerative removal of trace carbon monoxide - Google Patents

Abstract

By the present invention, a process is provided to use a modified clinoptilolite adsorbent suitable for the separation of carbon monoxide from hydrogen and hydrocarbon streams without adsorbing hydrocarbons such as paraffins and olefins. In typical applications in platforming units within refineries, these hydrogen streams contain from 5 to 20 parts per million of carbon monoxide. In other applications the level of carbon monoxide may be higher. The separation of carbon monoxide from the hydrogen stream is achieved by using a clinoptilolite molecular sieve that has been ion-exchanged with at least one cation selected from lithium, sodium, potassium, calcium, barium, and magnesium.

Description

REGENERATIVE REMOVAL OF CARBON ONOXIDE TRACES BACKGROUND OF THE INVENTION The present invention relates to processes for the purification of hydrocarbon and hydrogen containing streams. More specifically, the present invention relates to processes for the use of adsorbents, including clinoptilolites modified to extract carbon monoxide from these streams. Clinoptilolites can be natural or synthetic, modified by ion exchange with one or more metal cations. There are processes for separating feed charges containing molecules of different sizes and shapes, by putting the feed stream in contact with an adsorbent, in which a component of the feed charge to be separated is strongly absorbed by the adsorbent than the other components. The component that is most vigorously adsorbed is preferably adsorbed by the adsorbent to provide a first product stream enriched with the non-adsorbed or weakly adsorbed component, as compared to the feed stream. After the adsorbent is loaded to the desired extent with the absorbed component, the conditions of the adsorbent are varied, that is, the temperature or pressure of the adsorbent is typically altered, so that the adsorbed component can be desorbed, so that a second stream of products enriched in the adsorbed component is produced, compared to the feedstock.The most important factors of these processes include the ability of the molecular filter for the more easily adsorbable components, and the selectivity of the molecular filter (i.e. , the proportion in which the components to be separated are adsorbed.In many of these processes, the preferred adsorbents are zeolites, due to their high adsorption capacity at low special pressures of the adsorbates, and to be chosen so that their pores are of appropriate shape and size to provide high selectivity in concentrating the adsorbed species. ia, the zeolites used in the separation of gas mixtures are synthetic zeolites. Although natural zeolites are readily available at low cost, natural zeolites are often not favored as adsorbents, because it is thought that natural zeolites are not sufficiently consistent in their composition to be used as adsorbents in such processes. However, there are relatively few synthetic zeolites with pores in the range of 0.3 to 0.4 nanometers, which is the pore size range of interest for various gaseous separations. The clinoptilolitas (to which from now on we will often refer to as "clino"), are a class of well-known natural zeolites, which have occasionally been proposed for the separation of gaseous mixtures, generally light gases such as hydrogen, nitrogen, oxygen , argon or methane. U.S. Patent 5,116,793 discloses a process for ion exchange of clinoptiloites with metal cations such as lithium, sodium, potassium, calcium, magnesium, barium, strontium, zinc, copper, cobalt, iron and manganese. This patent is incorporated herein in its entirety. US Pat. No. 4,935,580 discloses exchanged ion clinoptilolites which remove traces of carbon dioxide and water from hydrocarbon streams. U.S. Patent 5,019,667 discloses the use of modified clinoptilolite, where at least 40 percent of the ion exchange cations in the clinoptilolite comprise one or more of lithium, sodium, potassium, calcium, magnesium, barium, strontium, zinc, copper, cobalt, iron and manganese. This clinoptilotite is used to extract ammonia from hydrocarbon streams. Accordingly, processes are sought in which carbon monoxide can be separated from hydrogen and hydrocarbons, without removing hydrogen and hydrocarbons as methane., ethane, ethylene, propane and propylene, by adsorption using adsorbents. It has been discovered that modified clinoptilolite adsorbents achieve this goal, as is the case with titanium silicates and natural zeolites including mordenite with pore size of 0.4 nanometers (and larger than 0.3 nanometer products). Furthermore, processes for production are sought of modified clinoptilolite adsorbents. The catalytic reformer unit is an integral part of, and also supplier of, the refinery's hydrogen production with the advent of low pressure catalytic reforming units and the presence of carbon monoxide (CO) in the gas has become more prevalent net of hydrogen from the reforming units. Some of the processes, such as the paraffin isomerization units that use this hydrogen, have catalysts that are very sensitive to CO (as well as other oxygenated compounds), and if carbon monoxide is not removed, the catalyst becomes contaminated. One of the methods currently used to eliminate carbon monoxide is to use a metanator, to react the hydrogen with carbon monoxide, which produces methane and water. Although the metanator is considered the primary tool to solve the problem of pollution, it is a capital-intensive solution, in addition to consuming energy and exhausting hydrogen.

Although some consideration has been given to using adsorbents to remove carbon monoxide in such processes, previously it was thought that the adsorbents that would eliminate carbon monoxide would co-adsorb hydrocarbons such as ethylene, which exist in significantly higher concentrations, thereby greatly decreasing the ability to extract carbon monoxide. SUMMARY OF THE INVENTION By means of the present invention there is provided a process for using a modified clinoptilolite adsorbent, suitable for the removal of carbon monoxide from streams containing hydrocarbons and hydrogen. In typical applications in platform units in refineries, these streams containing hydrocarbons and hydrogen contain between 5 and 20 parts per million of carbon monoxide. In other applications, the level of carbon monoxide may be higher. For example, there may be currents with up to 1% carbon monoxide to be modified. These streams containing hydrocarbons and hydrogen may also contain hydrocarbons, including ethane and ethylene. The separation of carbon monoxide in the stream is obtained using a clinoptilolite molecular filter that has exchanged ions with at least one cation selected from lithium, sodium, potassium, calcium, barium and magnesium. Preferably the clinoptilolite adsorbent exchanges ions to such an extent that at least 60% of the total cations in the clinoptilolite are occupied by one or more of the cations described. The process eliminates at least 50%, and preferably at least 90%, of the carbon monoxide from these hydrocarbon-containing streams, without removing hydrocarbons such as ethylene. The present invention provides the use of an adsorbent to remove carbon monoxide, including the use of a modified clinoptilolite, wherein at least 50%, and preferably at least 40% of the ion exchange cations in the clinoptilolite comprise one or more than lithium, potassium, calcium, sodium, magnesium or barium. A process by which modified clinoptilolites are produced is subjecting a clinoptilolite of natural occurrence to ion exchange with a solution containing sodium cations, until at least 40% of the non-sodium ion exchange cations in the clinoptilolite have been replaced by sodium cations, which produces a sodium clinoptilolite, and then subject the clinoptilolite sodium to an exchange of ions with a solution containing cations of one or more of lithium, sodium, potassium, calcium, barium and magnesium. In another process, the modified clinoptilolite is produced by directly submitting a clinoptilolite to ion exchange with a solution containing cations of one or more of lithium, sodium, potassium, calcium, barium and magnesium. The preferred clinoptilolite exchanges ions with calcium. Other adsorbents having an pore size intermediate between the pore size of zeolites 3A and 4A can be used, such as titanium silicates, which can be modified to have specific pore sizes and shapes. In yet another process, the present invention comprises a process for the production of high purity hydrogen from a catalytic reformer, wherein the process comprises the steps of passing at least a portion of gaseous hydrogen stream produced in the catalytic reformer, and comprising carbon monoxide, to an adsorbent bed containing an adsorbent having effective pore size and shape that excludes hydrocarbon molecules, and that is large enough to adsorb carbon monoxide molecules. At least a portion of the hydrogen gas stream having a reduced concentration of carbon monoxide is passed to a catalytic conversion process of hydrocarbons, which require hydrogen containing low levels of carbon monoxide. The catalytic reformer unit is an integral part of, and supplier of the refinery's hydrogen production. With the advent of low pressure catalytic reforming processes, the presence of carbon monoxide in the gaseous hydrogen net is becoming more prevalent. Part of the processes, such as paraffin isomerization units, that use this hydrogen, have catalysts that are very sensitive to this CO (as well as other oxygenates). The current method to eliminate this pollutant is to use a methanator, which besides being capital intensive, also wears out the utilities, including hydrogen. Frequently an adsorption unit of thermal variations is used to dry the hydrogen. The judicious use of an adsorbent as clino (in its sodium or calcic forms) to exclude C2 + hydrocarbons in the hydrogen stream can allow CO adsorption. An existing oscillating bed adsorption system can be used in most cases, and also modify the cycle time and the adsorbents that are currently used. DETAILED DESCRIPTION OF THE INVENTION A thermal oscillation adsorption system is used to dry the hydrogen in a paraffin isomerization unit. The judicious use of an adsorbent such as clinoptilolite (in its sodium or calcic forms) to exclude C2 + hydrocarbons in the hydrogen stream can allow CO adsorption. In most cases an existing thermal oscillation adsorption system can be used for dehydration and CO removal. Using the existing thermal oscillation hydrogen dryers in the paraffin isomerization units (Butamer ™ and Penex ™), the cycle can be modified, and a bed composed of adsorbents can be used in the existing vessels for the simultaneous extraction of water and CO. In the past, it was not considered practical to use the thermal oscillation process for the extraction of CO, due to the co-adsorption of heavier hydrocarbons from the process stream, which severely limited the CO capacity of the adsorbent. This limitation is solved by using an adsorbent with a pore size and pore-opening shape that excludes the hydrocarbon species that would normally be co-absorbed. The present invention provides lower capital and operating costs; in many cases, existing vessels and equipment can be used to improve performance, eliminating a severe catalyst pollutant (in this case for the paraffin isomerization unit). Most of the hydrogen dryers designed for most of the paraffin isomerization units can be used, both for dehydration and for the extraction of carbon monoxide. Accordingly, these thermal oscillation units have the ability to extract contaminants in addition to dehydration. Prior to the present invention, it was not thought that the traces of CO could be effectively removed from this hydrogen current using a thermal oscillation process, due to the very low capacity expected as a consequence of the C2 + hydrocarbon coadsorption. The concentration of CO in the net hydrogen current of the catalytic reformer unit is typically in the range of 5 to 20 ppm (m). This level of contaminants can be eliminated by using a bed composed of adsorbent for the removal of water, followed by an adsorbent for the removal of CO. Accordingly, it is expected that the operation of the paraffin isomerization catalyst would be improved without the costly addition of a metanator. Although many adsorbents by themselves can adsorb trace levels of CO of hydrogen, before the present invention it was to be expected that in the presence of hydrocarbons, hydrocarbon coadsorption would occur and that it would considerably diminish its capacity for typical adsorbents that would be thermally regenerated. It is known that the adsorption properties of many zeolites, and therefore their ability to separate gas mixtures, can be limited by incorporating various metal cations into the zeolites, typically by ion exchange or by impregnation. Accordingly, potassium A is commonly referred to as having an effective pore diameter of 0.3 nanometers and similarly reference is made to calcium A as having an effective pore diameter of 0.5 nanometers. The term "effective pore diameter" is used in order to functionally define the pore size of a molecular filter in terms of the molecules it can adsorb, instead of the actual dimensions that are very often irregular and non-circular, it is say ellipticals DW, in ZEOLITE MOLECULAR SIEVES, John Wiley and Sons (1974) incorporated herein by reference, which describes effective pore diameters on pages 633 to 641. In most cases, changes in the adsorption properties of the zeolites after ion exchange are consistent with a physical blockage of the pore opening by the introduced cation; in general, in any given zeolite, the greater the radius of the introduced ion, the smaller the effective pore diameter of the treated zeolite (for example, the pore diameter of zeolite potassium A is less than the zeolite calcium A), measured by the size of the molecules that can be adsorbed to the zeolite. However, this is not the case with clinoptilolites that demonstrate an unpredictable relationship and that is not a simple function of the ionic radii of the introduced cation, ie pore blocking. For example, unlike the previously described calcium and potassium forms of zeolite A, clinoptilolite produces the opposite effect with these two cations. That is, the potassium cations, which are larger than the calcium cations, provide a clinoptilolite that has an effective pore diameter greater than the clinoptilolite calcium ion exchange. In fact, an ion exchange clinoptilolite with calcium, with a calcium content equivalent to 90% of its ion exchange capacity, defined by its aluminum content, essentially includes nitrogen and methane. On the other hand a clinoptilolite ion exchange with potassium, with a potassium content equivalent to 95% of its ion exchange capacity, quickly adsorbs nitrogen and methane. Here, the clinoptilolite containing the cation with the largest ionic radii, ie potassium, has a larger pore than the clinoptilolite containing the cation with the smaller ionic radius, ie calcium. The clinoptilolites used in the process of the present invention may be natural or synthetic. It is not easy to synthesize the synthetic clinoptilolites, as noted in ZEOLITE MOLECULAR SIEVES, supra on page 260, and therefore natural clinoptilolites are preferred. However, natural clinoptilolites are of variable composition, and chemical analyzes show that the cations in clinoptilolite samples from various mines vary widely. In addition, natural clinoptilolites frequently contain significant amounts of impurities, especially soluble silicates, which can cause difficulties in the aggregation or granulation of clinoptilolite (which will be discussed later in greater detail), or may cause undesirable side effects that will inhibit the practice of the present invention. In some applications, the mesh form of the absorbent is preferred to its granular form. In accordance with the present invention, clinoptilolites are required to be modified by ion exchange with at least one metal cation, in order to establish the appropriate pore size and shape to perform the separation and establish a uniformity of composition. Some of the cations that are useful for exchanging ions with clinoptilolites are lithium, potassium, magnesium, calcium, sodium and barium. Therefore any cation having the desired effect on the pore sizes can be used for ion exchange. In addition, the choice of a particular cation may be dependent on the characteristics of the initial material. Desirably, the exchange of ions is continued until the final ion exchange product contains more than 40% of the desired cations. The preferred metal cations for the treatment of the clinoptilolites used in the process of the present invention are calcium, magnesium and barium, where calcium is especially preferable. When calcium is used as the ion exchange metal cation, it is preferred that the exchange of ions be continued until at least 60% of the cations in the clinoptilolite are calcium cations. It should be noted that the exchange of ions can be carried out in two or more steps. For example, ST can use ion exchange to provide an initial material of uniform composition, and suitable for an additional ion exchange to modify the pore sizes. Accordingly, an additional ion exchange can be used in order to compensate for inherent differences in the raw material of natural occurrence, thereby improving the carbon monoxide separation performance of hydrocarbons and hydrogen. Since clinoptilolite is a natural material, the particle sizes of commercial products vary, and the particle size of clinoptilolite can affect the speed and integrity of the ion exchange reaction. Techniques for ion exchange of zeolites such as clinoptilolite are well known to those skilled in the art of molecular filters, and will therefore not be described in detail herein. In ion exchange, the cation is conveniently present in the solution, in the form of its water-soluble salt form. It is desirable that ion exchange be continued until at least 40%, and preferably at least 50%, of the content of the cations is the desired cation. It is convenient to continue the exchange of the ions until it is no longer possible to easily introduce additional amounts of the desired cation to the clinoptilolite. To ensure maximum replacement of the original clinoptilolite cations, it is recommended that ion exchange be performed using a solution containing a quantity of the cation to be introduced that is between 2 to 100 times the ion exchange capacity of the clinoptilolite. Typically, the ion exchange solution will contain between 0.1 to 5 moles per liter of the cation, and will be contacted with the original clinoptilolite for at least one hour, ion exchange can be performed at room temperature, although in many cases, Performing the exchange of ions at elevated temperatures, generally less than 100 ° C, accelerates the ion exchange process. Since clinoptilolite is a natural material of variable composition, the cations present in the crude clinoptilolite vary, although typically the cations include a large proportion of alkali metals. It is typically found that, even after the most exhaustive ion exchange, a proportion of the original clinoptilolite cations, ie between 5 and 15% by weight, can not be substituted with other cations. However, the presence of this small proportion of the original clinoptilolite cations does not interfere with the use of clinoptilolite of ions exchanged in the process of the present invention. As noted above, any of the modified clinoptilolites used in the present invention can be directly prepared directly by exchange of natural clinoptilolite ions with the appropriate cation. However, in practice this direct ion exchange may not be the most economical or practical technique. Being natural minerals, clinoptilolites are of variable composition and frequently contain large amounts of impurities, especially soluble silicates. To ensure an ion exchange as complete as possible, and also to remove impurities, it is desirable to effect ion exchange of the clinoptilolite using a large surplus of the cation to be introduced. However, and for example, if a large surplus of barium is used in such an exchange of ions, the removal or recovery of barium from the ion exchange solution used presents a difficult environmental problem, in view of the limitations set forth in the release. of barium salts contaminants to the environment. In addition, some impurities, including some silicates, which are removed in an exchange of sodium ions, are not eliminated in a barium ion exchange because the relevant barium compounds are much less soluble than their sodium counterparts. When the clinoptilolites of the present invention are used in industrial adsorbents, it may be preferable to add (granulate) the modified clinoptilolite to control the diffusion of macropores, or in an adsorption column of industrial size, where the sprayed clinoptilolite can be made more compact, and with that block, or at least significantly reduce the flow through the column. Those familiar with molecular filter technology know conventional techniques for adding molecular filters; these techniques generally involve mixing the molecular filter with a binder, which is typically a clay, causing the mixture to form an aggregate, typically by extrusion or bead formation, and heating the clay and molecular filter mixture to a temperature of between 500 ° and 700 ° C to convert the green aggregate into one resistant to crushing.

The binders used to add the clinoptilolites may include clays, silica, aluminas, metal oxides and mixtures thereof. In addition, clinoptilolites can be formed with materials such as silica aluminas, silico-aluminas, silico-magnesias, silico-zirconias, silico- toria, silica-beryllium and silica titanium. As well as ternary compositions, such as silica-alumina-thorium, silica-alumina-zirconia and clays present as binders. The proportions relative to these materials and the clinoptilolites can vary widely with the clinoptilolite content varying between 1 and 99 percent, and preferably between 60 and 95 percent of the composite material. When it is desired to form the clinoptilolite in aggregates before use, these aggregates desirably have a diameter of between 1 to 4 mm. To avoid the aforementioned difficulties, it is occasionally preferred to produce modified clinoptilolites other than sodium clinoptilolite, first submitting the crude clinoptilolite to an ion exchange with sodium, add the sodium clinoptilolite produced in this way, and then carry out a second ion exchange in the added material to introduce the desired non-sodium cations. Before being used in the process of the present invention, clinoptilolites need to be activated by calcination, ie heating. If clinoptilolite is added as discussed above, the heat required for aggregation will normally also be sufficient to effect activation, so no additional heating is required. However, if you do not want to add clinoptilolite, a separate activation step will usually be required. Also, if the ore is used directly, or if ion exchange is performed after aggregation, a separate activation step will usually be necessary. Clinoptilolites can be activated by heating in air, in an inert atmosphere or in a vacuum, to a temperature and for a time sufficient to cause the clinoptilolite to be activated. The term "activated" is used herein to describe an adsorbent that has a reduced water content as compared to being in equilibrium with atmospheric air. Typical activation conditions include a temperature between 100 ° and 700 ° C, and a lapse of between 30 minutes to 20 hours, which is sufficient to reduce the water content of clinoptilolite to 0.2 to 2% by weight. Preferably, the clinoptilolites are activated by heating in a purge stream of air or nitrogen or in a vacuum at between 200 ° and 350 ° C, for a suitable period. The temperature necessary for the activation of a particular specimen of clinoptilolite can easily be determined by routine empirical tests, where typical adsorption properties, such as absolute charges or adsorption rates, are measured with samples activated at various temperatures. Although the exchange of clinoptilolite ions yields a modified clinoptilolite having a consistent pore size, the exact pore size depends not only on the metal cations exchanged, but also on the thermal treatment of the product after an ion exchange. In general, there is a tendency for the pore size of the modified clinoptilolites of the present invention to decrease with exposure to a higher temperature. Therefore, in selecting an activation temperature for modified clinoptilolites care should be taken not to heat modified clinoptilolites at temperatures that cause such severe pore size reductions that adversely affect the operation of modified clinoptilolite in the process of the present invention, that is, more than 700 ° C. Although the behavior of modified clinoptilolites when exposed to heat limits the activation temperatures that can be used, the thermal reduction in pore sizes offers the possibility of "fine-tuning" the pore size of a modified clinoptilolite to optimize its operation in the process of the present invention. The process of the present invention is primarily oriented to eliminate traces of carbon monoxide from hydrogen and hydrocarbon streams, where the presence of even a few parts per million of carbon monoxide may be undesirable. Since these types of processes involve the separation of smaller amounts of carbon monoxide from much larger amounts of hydrogen and hydrocarbon streams, they can be effected in the conventional manner by simply passing the hydrogen stream through a bed of clinoptilolite which is normally in the form of added during the adsorption step. As the adsorption step continues, a so-called "front" between the clinoptilolite loaded with carbon monoxide and the clinoptilolite without this charge develops in the bed and this front moves through the bed in the direction of gas flow . Preferably, the temperature is maintained during the adsorption step between -15 ° and + 100 ° C. Before the front reaches the downstream end of the bed (which would allow the impure hydrogen gas to leave the bed), the bed is preferably regenerated by cutting the flow of hydrogen gas and passing a purge gas through the bed that causes desorption of the bed carbon monoxide. In industrial practice, the purge gas is typically natural gas or vaporized isomer product, heated to a temperature within the range of 100 ° to 350 ° C, and this purge gas is also satisfactorily in the process of the present mention. It is also important to note that other adsorption cycles can be used such as pressure swing or purge cycles. These cycles do not form a critical part of the present invention, as those skilled in the art know, and therefore will not be discussed in more detail herein. The following examples are provided, by way of illustration only, to show the preferred processes of the present invention. All adsorption measurements are at 23 ° C unless otherwise indicated. In addition, from the separation factors given in the form that is based on the data of the examples, it was concluded that clinoptilolite with calcium exchange is the best candidate that has been tested to date to eliminate CO from net hydrogen gas. EXAMPLES Example 1 The modified clinoptilolite was produced according to the following procedure: First, the amount of salt solution necessary for the following steps was determined: The clinoptilolite of interest is selected, and the weight of its formula is estimated from the moles and molecular weights of each species of oxide present. Then, two equivalents are determined per gram of active sample for each of the interchangeable cations present, and the values are added. The amount of salt and solution stoichiometrically required to displace all the cations (if a total exchange is desired) in the active material is calculated. Typically we multiply these values by 4, to calculate imperfections in the sample and the conditions in the exchange. The molarity of the salt solution was limited to 0.4 or less, than the favorable for most exchanges (although not for all). The salt exchange solution is formed; and its pH is adjusted as follows: the actual amount of salt used is measured and recorded. The salt is added to a recorded cuvette (accuracy is not objectionable when operating with surpluses), and deionized water is added to the appropriate mark. If necessary, a bottle is used for large volumes of solution. A solution based on 10% by weight (example: Ca (OH) 2 for a CaCl 2 solution) in water is prepared to adjust the pH of the salt solution to a pH between 9.9 and 10.2. This is favorable for most exchanges. Aliquots of between 0.3 and 0.5 milliliters of the base solution are added to the salt solution, and the pH of the salt solution is measured with a pH paper after each addition. Enter the amount used for future reference. The rinse solution is prepared, and its pH is adjusted as follows: the rinse solution uses the same salt as the exchange solution, but very divided (example: if the exchange solution is 0.2M, then the rinse it must be 0.2 / 20, or 0.01 M. The amount of salt needed is measured, and its mass is written in. The preparation is completed with the solution and the pH adjustment in the same way as the exchange solution. of exchange as follows: with a ring slightly greased with silicones, it is attached to the column and the Teflon part of the bottom, through the top of the column, a piece of stainless steel mesh is inserted to cover the hole in the bottom part, over the mesh, 0.2 g of 6mm glass beads (half of a bottle) is added to work as a preheating section.Then three pieces of stainless steel are added to separate the adsorbent sample from the accounts.It weighs and r egistra real sample amount of clinoptilolite, and added to the column. Two pieces of stainless steel mesh are placed over the sample, and the column is filled near the top with 6mm glass beads (to reduce dead volume). The upper ring (slightly greased) and the piece are installed. If, as is typical, a heat exchange is performed, the water bath is opened and the meter is set at 88 ° C, or less if desired.

The exchange is completed as follows: start pumping the salt solution at 35ml / minute. The start time and the measured flow rate are noted. The end of the effluent from the tube is placed in a bucket or bottle. The water bath is checked and occasionally pumped to make sure it is operating properly. Once the exchange solution is completely supplied, immediately start pumping the rinsing solution at the same speed and temperature. When the pumping of the rinse solution is completed, the effluent tube is connected to the air and the inlet end of the column tube is placed in the waste container. By maintaining the temperature of the column, air is allowed to pass through the column at a reasonable rate to remove the clino sample (1 to 3 hours). The water bath is turned off to allow the column to cool, but maintains the air flow to aid in cooling.When the column cools, the sample is carefully drawn through the bottom of the column.The sample is activated and sent for analysis as follows: For a smooth extraction of water , this "preactivation" can be used with air hose Ramp (Hrs) Temp. (° C) Wait (hrs) 0.5 50 0.5 1.5 100 5 1.5 150 4 1.5 200 2 1.5 250 2 1.0 25 2 Finally, the sample is vacuum-activated for 3 hours at 350 ° C, allowed to cool to 80 ° C, bottled and a portion sent to analytical tests (usually LOI and ICP). Example 2 In initial tests with various zeolite materials, only the clinoptilolite from the barium exchange exhibited sufficient CO adsorption capacity at low partial pressures to be of interest in purification applications. An initial sample of modified clino was produced by exchange with sodium with the fresh clino mineral. This initial clue to produce the interchangeable forms of ions of potassium, lithium and calcium to find an optimal adsorbent of CO that continues to exclude hydrocarbons. The mixtures and chemical analyzes were sent to verify the degree of ion exchange as shown in the following Table 1. The CO adsorption of the materials was then tested. After carefully activating the samples, CO was absorbed at a partial pressure of 6 torr for 3 hours. Then the CO pressure was increased to 46 and adsorbed for 2 hours. (Table 2) Apparent an equilibrium was achieved in both conditions. The samples were then subjected to vacuum 5 overnight at 360 ° C to reactivate them. The next day, the co-adsorption of hydrocarbons was tested. First they were tested with propane at 250 torr and 21 ° C (Table 3) and, after another activation, ethylene at 700 torr and 21 ° C (Table 4. Four samples were previously made materials, and they were proved as such. Two were samples of clinoptilolite with. barium. The CO data for these two were almost identical, which verifies the reproducibility of the McBain CO test technique that was used. The Mg clone was clino exchanged with magnesium. The clino exchanged with sodium is a mesh product, and is the current commercial product sold in the hydrocarbon processing industry. Three forms of ion exchange were made from this material: the calcium, lithium and potassium forms of clino. Table 1 For CO absorption, the following order was found at a partial pressure of CO of 7 torr (Table 2): The results showed that Clino Ba > Clino Ca > Clino Li > Clino Na in the form of granules > Clino Mg > Clino Na = Clino K. Table 2 For the exclusion of propane (less is better) the following was discovered (Table 3): a summary of the results shown in Table 3 is that Clino adsorption Mg = Clino Ca = Clino Na = Clino K = Clino Li < Clino Ba < Granules Clino Na Table 3 For the exclusion of ethylene (less is better) the following was discovered (Table 4): the results at 960 minutes showed that Clino Na = Clino Ca < Clino Mg «Clino K < Clino LKClino Ba < Clino Na (P). Table 4 Although in certain circumstances other forms of clino like the sodium form that also works, for the particular application of purification of H2, the exchange version with clino is the best candidate for the elimination of carbon monoxide, and that at the same time does not adsorb hydrocarbons. Example 3 Since the clino exchanged with calcium was the best combination of good CO load with the minimum amount of hydrocarbon coadjustment (propane, ethylene), other studies were made with the clino calcium exchange forms. Two different crude clino minerals were tested. Exchanging the raw mineral with calcium, without passing through the exchange of sodium to form a mineral exchanged with sodium first, is a significant cost reduction. Each mineral was exchanged in column. Table 5 shows the chemical analysis of the initial mineral and the form exchanged with calcium.

Table 5 Due to its unique layered structure, the clino pores close easily. The higher the activation temperature, the more pore-closing effect could be produced. Accordingly, samples of calcium exchange forms from two clones were heated together with fresh clino mineral at 500 ° C for one hour. This provided an indication of the ease with which a pore-closing effect occurs in our materials. The adsorption of CO from the materials in the gravimetric adsorption apparatus was then tested. McBain-Bakr After carefully activating the samples, CO was adsorbed to a partial pressure of 6 torr for 1.9 hours, then the CO pressure was increased to 46 torr and adsorbed for one hour (Table 6) For the adsorption of CO at room temperature with fresh material , the following order was discovered (Table 6) Ca TX-764 > Ca EP-9174 > Ca TSM-140 > Ca TX-764 * »TSM-140 > CaTSM-14 * > TX-764 * = TX-764 Table 6 Results Me Bain Co * Calcined at 496 ° C for one hour with air (dry) Apparently balance was obtained after one hour with the data points to 6 torr due to the very small change in weight between the readings of one hour and 1.9 hours compared to the one hour reading For the second point (46torr), the first reading was taken at 30 minutes and the second at an hour. The equilibrium is obtained at this shorter time, which indicates that the adsorption rate of carbon monoxide is large. These samples were then subjected to vacuum at room temperature for 1.5 hours and most of the CO was desorbed (Table 7), and then the samples were vacuum-activated overnight at 350 ° C. The following day, its adsorption of ethylene 750 torr and 22 ° C was tested. For the exclusion of ethylene (the less the better) the following was discovered (Table 7): CaEP1974 < CaTSM-140 * = CaTX-764 < TSM-140 < CaTSM-140 «CaTX-764 < TX-764 Table 7 McBain Result of Desorption CO and Adsorption of? * Calcined at 496 C for one hour with air (dry) After the ethylene adsorption, the McBain was evacuated and flooded with helium to keep the samples dry over the weekend. Then ethylene was re-introduced at 750 torr. Some of the samples lost weight at the first point of CO adsorption, which was 6 torr and 2 hours. Therefore, the CO speed or final CO charge in these samples is not clear. The CO pressure was increased to 46 torr, and the difference between 6 and 46 could be attributed only to the adsorption of CO, although there is no way of knowing how much ethylene was desorbed in this lapse. An approximation can be made if we only see the difference between 6 and 46 torr, and we assume that any ethylene desorption would be negligible. If so, then the highest CO values would belong to the best candidates when ethylene was present. The order of the CO capacity under these conditions is as follows (Table 8): CaTX-764 * = CaEP-9174 > Ca TSM-140 > CaTX-764 = TX- 764 * > CaTSM-l40 * = TSM-140 > TX-764 Table 8 McBain CO Adsorption Result After ethylene pre-loading The samples were then turned on overnight at 350 ° C under vacuum and ethane was introduced into the system. Apparently, the ethane content of the net hydrogen gas of the typical catalytic reformer is significantly higher than the trace levels of ethylene that can be found. Therefore, the exclusion of ethane is much more important. The samples were exposed to ethanol at 750 torr and 22 ° C for 2 hours and overnight. The data are presented in Table 9. The material with the lowest ethane adsorption should be the best. The order of ethane adsorption that was found was: CaEP-9174 < Ca TSM-140 * < TX-764 * = CaTX-764 * < TSM-140 = CaTSM-140 < CA TX-764 < TX-T64 Table 9 McBain Outcome of Adsorption of Tantalum on Calcium Cunos ^ Calcined at 496 c for one hour with air (dry!) Apparently, the calcination of the exchanged clines has an advantageous effect on the functioning (more notably in the exclusion of hydrocarbons) of the clino, regardless of the type of cation. Based on the data, it appears that EP-9174 exchanged with calcium (from the clino exchanged with sodium EP-9174), although chemically not very different from the crude mineral exchanged with calcium, is still a better candidate for the applications of H2 gaseous net of the platforms

Claims (10)

1. CLAIMS 1. A process for separating a smaller proportion of carbon monoxide from a stream containing hydrocarbons or hydrogen, where the process comprises contacting the carbon monoxide-containing mixture with an adsorbent with effective pore sizes and shapes that exclude molecules of hydrocarbons, and that is large enough to adsorb carbon monoxide molecules.
2. 2. The process of claim 1, wherein the adsorbent is a natural clinoptilolite subjected to ion exchange at least one metal cation from the group consisting of lithium, sodium, potassium, calcium, magnesium and barium, thereby causing the carbon adsorbed selectively on clinoptilolite.
3. 3. The process of claim 2 wherein the metal cation is selected from the group consisting of calcium, barium and mixtures of calcium and sodium.
4. 4. The process of claim 1, wherein the natural clinoptilolite is heated to a temperature of between 100 and 700 ° C for a suitable time.
5. 5. The process of claim 1, wherein the content of the carbon monoxide in the stream containing hydrogen or hydrocarbons is not greater than one percent by weight.
6. 6. The process of claim and wherein the hydrogen-containing stream is produced from a catalytic reforming unit, where at least a portion of the hydrogen-containing stream passes into an adsorbent bed, which contains an adsorbent that has a size and shape effective pores that excludes hydrocarbon molecules, and that is large enough to adsorb carbon monoxide molecules and then pass at least a portion of the hydrogen gas stream having a reduced concentration of carbon monoxide to a catalytic conversion process of hydrocarbons, which requires hydrogen and which contains low levels of carbon monoxide.
7. The process of claim 1, wherein the adsorbent is used for hydrogen purification of composition to an isomerization unit of paraffins and olefins.
8. The process of claim 1, wherein the adsorbent is used for purification of olefins in an olefin production process.
9. 9. The process of claim 1, further comprising claiming the adsorbent.
10. 10. The process of claim 1, further comprising removing carbon dioxide.