Purification of alcoholic dewatered product streams

Abstract

A process is provided for treating a stream comprising light olefins and carbon monoxide by passing the stream through a bed containing a copper-containing material. Removal of carbon monoxide is required to prevent catalyst poisoning in downstream oligomerization reactors. The carbonaceous material converts carbon monoxide and hydrogen to carbon dioxide and water. The olefin stream is then dried and passed to an oligomerization step. Three beds may be present such that these beds may alternate a regeneration step, a reaction step with CO and H2, and an O2 scavenging step.

Description

[0001] This invention relates to the removal of carbon monoxide from the product stream of an alcohol dehydration reactor. More specifically, this invention relates to the addition of oxygen to regenerate copper-containing materials while preventing carbon monoxide, oxygen, and hydrogen from entering the downstream environment. Background Technology

[0002] Light olefins are produced via alcohol dehydration prior to oligomerization in the step of generating sustainable aviation fuel. The main steps after dehydration involve oligomerizing the light olefins to approximately C8 to C96. 16 The olefins are then hydrogenated to produce alkanes. The gas stream from the dehydration unit can be compressed via a four-stage compressor before being sent to the oligomerization section. In the case of ethanol dehydration, the ethanol dehydration effluent gas stream consists of approximately 98% by weight ethylene, and the remaining approximately 2% by weight consists of carbon monoxide, carbon dioxide, hydrogen, other olefins, and oxygen-containing compounds. While components such as carbon dioxide and hydrogen do not inhibit the oligomerization process, carbon monoxide deactivates the oligomerization catalyst.

[0003] In the past, carbon monoxide was removed from ethylene streams by fractionation. However, under the conditions encountered in this paper, the much higher CO levels and the presence of hydrogen would result in a very short catalyst lifetime without using the method described herein. Summary of the Invention

[0004] Dehydration of alcohols is a crucial step in the conversion of alcohols into jet fuels. Specifically, the ethanol dehydration reaction is a key step in the conversion of ethanol into jet fuels. Ethanol is dehydrated to ethylene, but carbon monoxide is one of the byproducts of this process. Carbon monoxide is detrimental to the performance of downstream oligomerization catalysts, which necessitates the removal of carbon monoxide from the ethylene stream before the oligomerization step. In one embodiment, carbon monoxide is removed to produce carbon dioxide via an oxidation reaction on a copper oxide adsorbent, wherein the used elemental copper adsorbent is continuously renewed back to copper oxide by adding oxygen for oxidation. The addition of oxygen also allows carbon monoxide and hydrogen to be converted into carbon dioxide and water at available elemental copper sites. When determining the appropriate amount of oxygen to be added, the presence of hydrogen must also be considered, as it will also react with the adsorbent. To provide a longer adsorbent lifetime, oxygen is co-fed at appropriate levels for continuous regeneration.

[0005] This method enables the ethanol-jet fuel process to operate for longer periods without requiring reloading of the oligomer catalyst due to carbon monoxide poisoning. This improves the economics of the method. Furthermore, the ability to continuously regenerate the CuO catalyst allows for extended use without reloading.

[0006] In another embodiment, a three-bed system using copper-containing materials is proposed. In one bed, CO and H2 are converted to CO2 and H2O in the absence of O2 to reduce copper oxide to copper. In another bed, any remaining CO and H2 are converted to CO2 and H2O in the presence of O2, allowing CuO to remain oxidized. In the third bed, excess O2 is removed by reacting with the reduced Cu. The first and third beds are periodically switched to maintain the O2 removal capacity of the third bed. Attached Figure Description

[0007] Figure 1 A simplified flow chart of a system for preparing a clean, light olefin feed stream for oligomerization is shown.

[0008] Figure 2 Step 1 of a flowchart of a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein a first bed in a leading position is regenerated, a second bed removes carbon monoxide and hydrogen, and a third bed in a lagging position removes excess oxygen.

[0009] Figure 3 Step 2 of a flowchart of a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed is prepared offline to remove oxygen, the second bed removes carbon monoxide and hydrogen, and the third bed in a lagging position removes oxygen.

[0010] Figure 4 Step 3 of a flowchart of a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed, in a hysteresis position, removes excess oxygen, the second bed removes carbon monoxide and hydrogen, and the third bed is offline and ready for regeneration.

[0011] Figure 5 Step 4 of a flowchart of a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed in a lag position removes excess oxygen, the second bed removes carbon monoxide and hydrogen, and the third bed in a lead position is regenerated.

[0012] Figure 6 Step 5 of a flowchart for a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed removes excess oxygen, the second bed removes carbon monoxide and hydrogen, and the third bed, which is in a leading position, is regenerated.

[0013] Figure 7 Step 6 of a flowchart for a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed is prepared offline for regeneration, the second bed removes carbon monoxide and hydrogen, and the third bed, in a lag position, removes oxygen.

[0014] Figure 8Step 7 of a flowchart for a three-bed system for removing carbon monoxide from an ethylene stream is shown, wherein the first bed is regenerated, the second bed removes carbon monoxide and hydrogen, and the third bed, in a lag position, removes oxygen. Detailed Implementation

[0015] The method for preparing jet fuel from ethanol includes the following key steps: acetaldehyde dehydration to prepare ethylene, and ethylene oligomerization to prepare longer-chain molecules that can be used in a series of jet fuel products. It has been found that some carbon monoxide is generated during ethanol dehydration. While components such as carbon dioxide and hydrogen do not inhibit the oligomerization process, carbon monoxide deactivates the oligomerization catalyst. The carbon monoxide level in the ethylene dehydration product is approximately 200 ppm at the beginning of the ethanol dehydration catalyst lifetime, and can reach up to 700 ppm at the end of the dehydration catalyst lifetime, and can increase to 1500 ppm if methanol is present in the ethanol feed stream of the ethanol dehydration reactor. Methanol is a common denaturant added to ethanol. To increase the cycle time of the oligomerization process, CO must be removed before the ethylene stream is fed to the oligomerization step to protect the oligomerization catalyst. In one proposed scheme, a container containing carbon monoxide removal material is installed upstream of a dryer container. Carbon monoxide removal materials that can be used include copper-containing materials, such as copper oxide. Carbon monoxide removal materials can be any metal oxide on a porous support (such as activated carbon, zeolite, mesoporous silica, alumina, and metal-organic frameworks) that selectively adsorbs CO from the product gas stream. The preliminary experiments discussed herein were conducted using copper oxide adsorbents. Copper oxide materials with oxygen injection were tested to remove CO from the product gas. However, the product stream contained approximately 300 ppm of hydrogen, which competed with CO to reduce CuO to Cu, making the oxidized copper (CuO) unusable for CO removal. Therefore, oxygen could be injected into the stream, utilizing a pre-reduced adsorbent. Since copper is reduced to its metallic state, it acts as a catalyst for the conversion of hydrogen to water. The effluent from the dehydration unit contained approximately 98% by weight ethylene, with the remainder consisting of carbon monoxide, carbon dioxide, hydrogen, olefins, and oxygen-containing compounds. Carbon monoxide is a poison to the catalyst in the oligomerization step at the expected ppm level and must be removed from the ethylene stream prior to the oligomerization step in this method. The CO concentration is approximately 200 ppm at the start of operation and can reach as high as 700 ppm at the end of operation, and can be increased to 1500 ppm if methanol is present as a common denaturant added to ethanol. However, other byproducts such as carbon dioxide and hydrogen do not interfere with the oligomerization catalyst. The reactions are as follows: CO + CuO → Cu + CO2, CuO + H2 → Cu + H2O (activation / reduction: pretreatment / regeneration), CO + CuO → Cu + CO2, H2 + CuO → Cu + H2O, ½ O2 + Cu → CuO (excess O2 is used for CO and H2 removal, and ½ O2 + Cu → CuO in the excess O2 scavenging bed).

[0016] It shows things like Figure 1 The simplified flow diagram and three-bed system in the design consider the needs for a bed to be regenerated, a bed to react with carbon monoxide, and a bed to recover excess oxygen. Current uses of catalysts or adsorbents are limited to their use as oxygen scavengers in their reduced state or to convert CO to CO2 in their oxidized state. In both cases, the adsorbent is replaced or regenerated once it has been used (in this context, "used" means the adsorbent was oxidized in the oxygen scavenger service or reduced in the CO oxidation service). Regeneration requires removing the adsorbent container from the service and performing the regeneration procedure with an external flow, which increases the operating and capital costs of the design. As previously described, the high CO and H2 levels in the feed, compared to other applications, would necessitate unreasonably large adsorption beds, expensive equipment (and electricity and nitrogen usage) for frequent regeneration, or some combination of both. This is undesirable from a process economics and environmental footprint perspective. This disclosure utilizes a novel process flow diagram that combines the two functions of an adsorbent to allow for continuous removal of CO from the feed without the need for external streams or additional equipment for regeneration, while meeting desired product specifications (specifically, removing CO without leaving O2 in the product).

[0017] By arranging a reducing adsorbent bed downstream of an oxidizing adsorbent bed and injecting O2 (in the form of air or pure O2) into the feed of the oxidizing adsorbent bed, complete conversion of CO and H2 can occur via reactions 1 and 2 without depleting CuO, as excess O2 will keep the adsorbent oxidized via reaction 3. The excess oxygen leaving the first bed then reacts with the reduced adsorbent in the second bed via reaction 3, and the product is free of CO and O2. The O2 injection can be controlled using an analyzer on the feed stream to measure CO, H2, and O2. Maintaining the actual ratio of O2 to CO+H2 at a desired target ratio (which can vary between approximately 1.05 to 1.95 parts O2 to 2 parts CO+H2) is achieved by controlling the setpoint on the flow controller on the O2 injection line. After a period of time, the second bed will become used due to the oxidation of Cu. To regenerate (reduce) this adsorbent bed, it can be brought into service upstream of the first bed. CO and H2 in the feed stream will react with the CuO in the adsorbent to reduce it to Cu. This will simultaneously reduce the amount of CO and H2 at the inlet of the second bed, thus the aforementioned control scheme will reduce the O2 flow rate. A third reducing adsorbent bed can be installed downstream of the oxidizing adsorbent bed to maintain oxygen removal from the effluent. The attached diagram illustrates how this three-bed flow chart can be designed to allow continuous operation. The positions of the first and third beds are periodically switched between oxygen removal (lag) and regeneration (lead) operations, and the oxidizing bed of the adsorbent remains operational between the other two beds. The valves shown can be actuated electronically or pneumatically, and all control functions described are executed by a programmable logic controller. The two oxygen removal beds will be of identical dimensions. Because the O2 flow rate is always set to less than 2x the theoretical amount (as described above), the regenerated lead bed will always be reduced by the feed faster than the lag bed. This will prevent oxygen permeation into the last bed. A heater or heat exchanger may be required on the feed stream to heat the gas shown in the diagram to the required temperature so that the reaction can continue. If the optimal temperatures for regeneration (reduction), CO+H2 oxidation, and O2 removal differ from each other, additional heaters, coolers, or heat exchangers (not shown in the figure) may be required between the adsorbent beds.

[0018] Figure 1A simplified flow diagram is shown, illustrating the dehydration of an ethanol stream into an ethylene stream, which is then treated to remove carbon monoxide and dry, with the clean ethylene being fed to oligomerization and dimerization units. Ethanol stream 10 is shown being fed to a dehydration reactor 40 along with water stream 20 heated by preheater 25, where the resulting vapor 30 is combined with ethanol stream 10. Reactor effluent stream 45 is shown leaving the dehydration reactor 40 and entering a separation tower 48 to separate into a gas stream 50 and a liquid stream 42. Liquid stream 42 is fed to a water stripping tower 44 to produce a reusable water stream 46. Gas stream 50, containing approximately 99.5% ethylene and impurities such as CO, CO2, and H2, is fed to a DEE adsorber 55 along with treated vapor 58, then to a scrubbing tower 60, then to pipeline 62, and a series of compressors 63, 64, and 65. A supply of oxygen 70 is added to an adsorbent bed 72 containing an adsorbent such as copper oxide to remove CO from the ethylene stream. The purified ethylene 73 is sent through line 80 to compressor 75, then to dryer 85 containing an adsorbent such as a 3A / 13X zeolite mixture, and then the clean ethylene stream 90 is sent to oligomerization and dimerization unit (not shown).

[0019] Figures 2 to 8 A seven-step cycle employing a system with three adsorption beds is illustrated in one embodiment of this disclosure. In the description of each step, the beds will be referred to by element number or by reference from left to right to bed A (120), bed B (140), and bed C (150). Figure 2In the first step shown, bed A is reduced, and the CO concentration at the inlet and outlet is equal, meaning regeneration is complete, and the bed can be moved from the leading position to the lagging position. Bed B oxidizes CO and H2 with the addition of excess O2. Bed C is partially oxidized and excess oxygen is removed. In bed A, no reaction occurs. In bed B, the reactions that occur include CO + Cu -> Cu + CO2, H2 + CuO -> Cu + H2, and ½ O2 + Cu -> CuO. In bed C, ½ O2 + Cu -> CuO. In the first step, feed 100 is shown as being heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. The heated feed 115 is fed to bed 120 through the open valve 118. Sensor 117 measures the carbon monoxide level. Valves 122 and 123 are closed. Line 124 is shown, positioned to feed the feed to bed 150 in a later step. Flow exits bed 120 via line 165 through open valve 169 and continues to bed 140. A CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters, with flow indication control 132 controlling valve 134, shown in the open position. Feed enters bed 140, and the treated feed is returned to bed 150 via line 142, through valve 144 in the open position, and then through valve 167 in the open position to product 200, which exits to be sent to the oligomerization and dimerization unit (not shown). Sensor 170 measures the amount of CO. Closed valves 166 and 168 are also shown. A pipeline 155 is provided so that the effluent from bed 150 can reach product 200 through valve 167.

[0020] Figure 3Step 2 of the eight steps is shown, where the open bypass valve 123 directs the feed to bed 140. Bed 120 is now isolated, and its valve is closed. CO and H2 are still being fully oxidized by excess oxygen in bed 140, and bed 150 is still removing excess oxygen. Bed 120 is offline, where the adsorbent is reduced and ready for purging services. In bed 140, the reactions occurring include CO + Cu -> Cu + CO2, H2 + CuO -> Cu + H2, and ½ O2 + Cu -> CuO. In bed C, ½ O2 + Cu -> CuO. In the third step, feed 100 is shown being heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 closed, the heated feed 115 bypasses bed 120. Sensor 117 measures the carbon monoxide level. Valve 123 is open, and valve 122 is closed. Feed continues to bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters at 130, where flow indication control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the treated feed is delivered to bed 150 via line 142, through valve 144 in the open position, and then to product 200 via valve 167 in the open position, which exits to be delivered to the oligomerization and dimerization unit (not shown). Sensor 170 measures the amount of CO. Valves 166, 168, and 169 are also shown closed because bed 120 is offline. Valves 166 and 168 are also shown closed. A pipeline 155 is provided so that the effluent from bed 150 can reach product 200 through valve 167.

[0021] Figure 4Step 3 of the 7 steps is shown, where bed 120 is put in a lag position by opening the valve from the outlet of bed 140 to the inlet of bed 120. The valve of bed 120 is opened to allow product inflow. The valves to and from bed 150 are then closed to take that bed offline. Bed 120 is now an oxygen-removed lag bed, bed 140 is still allowing CO and H2 to react with excess oxygen, and bed 150 is isolated. More specifically, the open bypass valve 123 directs feed to bed 140. Bed 120 is now isolated, and its valve is closed. CO and H2 are still being completely oxidized by excess oxygen in bed B, and bed C is still removing excess oxygen. Bed 120 is now an oxygen-removed bed with ½ O2 + Cu -> CuO. In bed 140, the reactions occurring include CO + Cu -> Cu + CO2, H2 + CuO -> Cu + H2, and ½ O2 + Cu -> CuO. Bed 150 is offline. In the fourth step, feed 100 is shown being heated by a heat source, such as steam, via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 closed, the heated feed 115 bypasses bed 120. Sensor 117 measures the carbon monoxide level. Valve 123 is open, and valve 122 is closed. Feed enters bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters at 130, where flow indicator control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the processed feed is sent through valve 146 to line 148, returning to bed 120, and then through valve 166 in the open position to product 200, which exits to be sent to the oligomerization and dimerization unit (not shown). Sensor 170 measures the amount of CO. Closed valves 167 and 168 are also shown. Valve 144 is closed so that fluid is not sent to bed 150 at this time. Closed valves 166 and 168 are also shown. Line 155 is provided so that when bed 150 returns to operation, the effluent from bed 150 can reach product 200 through closed valve 167.

[0022] Figure 5Step 4 of the 7-step method is shown. Bed 150 is in the pre-regeneration position by opening the feed valve 146 leading to bed 150 and opening valve 168 connected to the outlet flow of bed 150. The bypass valve 123 is then closed. As CO and H2 begin to be consumed by bed 150, the oxygen demand decreases and the oxygen flow rate is reduced. Feed 100 is shown as being heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 closed, the heated feed 115 bypasses bed 120. Sensor 117 measures the carbon monoxide level. Valve 123 opens, and valve 122 closes. Feed continues to bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters at 130, where flow indication control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the treated feed is returned to bed 120 via line 142, through valve 146, and then flows to product 200 via valve 166, which is sent to the dimerization and oligomerization reactor. Valve 144 is closed, so fluid is not sent to bed 150 at this time. In the open position, fluid reaches bed 150 and then reaches product 200 via valve 167, which is in the open position, and exits to be sent to the oligomerization and dimerization unit (not shown). Sensor 170 measures the amount of CO. Valve 168 is also shown open.

[0023] Figure 6Step 5 of the 7-step method is shown. Once the CO concentrations at the inlet and outlet of bed 150 are equal, the bed is fully regenerated and can be returned to the hysteresis position. Bypass valve 146 is opened, and the valve leading to bed 150 is closed. Feed 100 is shown as being heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 closed, the heated feed 115 bypasses bed 120. Sensor 117 measures the carbon monoxide level. Valve 123 is opened, and valve 122 is closed. Feed continues to bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters at 130, where flow indicator control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the treated feed is returned to bed 120 via line 142, through open valve 146, and then flows to product 200 via open valve 166, which is sent to the dimerization and oligomerization reactor. Valve 144 is closed, so fluid is not sent to bed 150 at this time. Valve 168 is now closed. Closed valves 166, 167, and 168 are also shown. Line 155 is provided so that the effluent from bed 150 can reach product 200 through valve 167.

[0024] Figure 7Step 6 of the 7-step method is shown. By opening valve 144 at the outlet of bed 150, regenerated bed 140 returns to the hysteresis position, and the effluent from bed 150 flows to product 200 through open valve 167. Bed 120 is offline, partially oxidized, and ready for regeneration; bed 140 has excess O2 for removing CO and H2; and bed 150 acts as a scavenger for excess oxygen. Feed 100 is shown heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 closed, the heated feed 118 bypasses bed 120, allowing the feed to proceed to bed 140. Sensor 117 measures the carbon monoxide level. Valve 123 opens, and valve 122 closes. Feed continues to bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 is introduced, wherein flow indication control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the treated feed is delivered to bed 150 via line 142, through the open valve 144, and then through the open valve 167 to product 200, which is then sent to the dimerization and oligomerization reactor. Valves 166 and 168 are closed, so that fluid is not delivered to any other bed at this time. Closed valves 166 and 168 are also shown. Line 155 is provided such that the effluent from bed 150 can reach product 200 through valve 167.

[0025] Figure 8 Step 7 of the 7-step method is shown. Bed 120 is in the pilot position to initiate regeneration by opening the valves for entering and exiting the bed, and is configured with... Figure 1Step 1 is the same as shown. Feed 100 is shown being heated by a heat source such as steam via valve 110. The steam flow is controlled by readings from temperature indicator control 106 and flow indicator control 107. A portion of the steam can be discharged through valve 108 and exit at 109. With valve 118 open, the heated feed 118 enters bed 120. Sensor 117 measures the carbon monoxide level. Valves 122 and 123 are closed. Feed continues to bed 140. The CO treatment air control system is shown with sensors 126 (H2), 127 (CO), and 128 (O2) to sensor 129, and the stoichiometry of O2 is maintained by control 125. Air or oxygen 130 enters, where flow indicator control 132 controls valve 134, which is shown in the open position. Feed enters bed 140, and the treated feed is delivered to bed 150 via line 142 and open valve 144. Then, flow 155 flows to product 200 via open valve 167, which is then sent to the dimerization and oligomerization reactor. Valves 166 and 168 are closed, so at this time, no fluid is sent to any other bed.

[0026] Examples 1-6

[0027] To demonstrate the removal of CO from an ethylene stream in the presence of H2, a series of experiments were conducted using a copper-based adsorbent. The conditions for these experiments are detailed in Table 1. A series of laboratory-scale experiments were performed to test the effectiveness of the copper-based adsorbent in removing CO from a C2= stream in the presence of H2.

[0028] Example 1 shows that when the feed composition contains only CO / CO2 and N2, the copper adsorbent completely removes CO, and no breakthrough is observed within 30 hours.

[0029] However, in Example 2, when H2 was introduced together with CO, breakthrough occurred earlier because the adsorbent reacted with both CO and H2 in a competitive reaction. In Experiment 1092, introducing oxygen at 2.3 times the stoichiometric ratio of CO + H2 pollutants resulted in no breakthrough for 30 hours.

[0030] Further studies of oxygen concentrations at excess or substoichiometric levels relative to CO+H2 pollutants showed no CO penetration over 20 hours and 18 hours, respectively (Examples 3 and 4).

[0031] Finally, in Example 5, ethylene was used instead of nitrogen to demonstrate that the concept would work in the desired feed environment at substoichiometric O2 concentrations relative to CO + H2 contaminants. No CO breakthrough was observed over 25 hours.

[0032] Table 1: CO removal from ethylene stream

[0033]

[0034] Table 2 shows the feed and product effluent samples used for offline compositional analysis. Offline analysis showed that ethylene hydrogenation to ethane had occurred, but to a very small extent, and was consistent with the online data. The experiment lasted approximately 25 hours, during which ethylene was present, and the stoichiometric ratio of O2 to CO+H2 contaminants present in the feed was 0.75. An initial induction period was observed where CO2 was completely adsorbed onto the copper-containing adsorbent. Once CO2 breakthrough was achieved, after 22 hours of operation, the increase in CO2 concentration corresponded to the sum of the feed CO2 concentration and the expected increase in CO2 if all CO had been converted during the 22-hour operation.

[0035] Table 2: Operating hours and concentrations analyzed offline

[0036]

[0037] Specific implementation plan

[0038] While the following description is presented in conjunction with specific embodiments, it should be understood that the description is intended to be illustrative and not to limit the scope of the foregoing description and the appended claims.

[0039] A first embodiment of the present invention is a method for purifying a stream containing light olefins, hydrogen, and carbon monoxide, wherein the method is carried out by feeding the stream and a second stream containing oxygen into one or more containers to contact a copper-containing material to remove carbon monoxide and hydrogen and produce a stream containing carbon dioxide and oxygen-free light olefins. One embodiment of the present invention is one, any, or all of the embodiments described in the first embodiment to the preceding embodiments of this paragraph, wherein the light olefin is ethylene. One embodiment of the present invention is one, any, or all of the embodiments described in the first embodiment to the preceding embodiments of this paragraph, wherein the volume of oxygen is less than 100% stoichiometric compared to the volume of carbon monoxide and hydrogen. One embodiment of the present invention is one, any, or all of the embodiments described in the first embodiment to the preceding embodiments of this paragraph, wherein the bed temperature is from about 60°C to about 175°C. One embodiment of the present invention is one, any, or all of the embodiments described in the first embodiment to the preceding embodiments of this paragraph, wherein the bed temperature is from about 110°C to about 150°C. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein at least 95% by volume of oxygen is converted to water or carbon dioxide within the vessel. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein the stream originates from an alcohol dehydration reactor. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein the feed stream contains at least 50 ppm CO. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein the feed stream contains at least 200-2000 ppm CO. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein the product stream contains less than 10 ppm CO. One embodiment of the invention is one, any, or all of the embodiments described in the first embodiment of this paragraph to the previous embodiments described in this paragraph, wherein the vessel operates at a pressure of about 200-800 psig and a GSHV of about 200-10,000 hr⁻¹. One embodiment of the invention is one, any, or all of the embodiments from the first embodiment to the preceding embodiments of this paragraph, wherein carbon monoxide and hydrogen react with a copper-containing material or oxygen to produce carbon dioxide and water.

[0040] A second embodiment of the invention is a method for removing carbon monoxide from a stream containing light olefins, hydrogen, and carbon monoxide. The method includes feeding the stream into a first container to contact a copper-containing material to produce a product stream containing light olefins, carbon dioxide, and water. The copper-containing material is first reduced to copper with the hydrogen and carbon monoxide and then oxidized by contact with oxygen. One embodiment of the invention is any one or all of the first embodiment to the preceding embodiments described in this paragraph, wherein a flow controller controls the oxygen volume in the second stream such that the ratio of oxygen to carbon monoxide and hydrogen within the container is maintained at approximately 1.05 to 1.95 parts oxygen to 2 parts carbon monoxide plus hydrogen. Another embodiment of the invention is any one or all of the first embodiment to the preceding embodiments described in this paragraph, wherein when the copper-containing material is in a reduced state in the first container, the stream is fed into a second container in an oxidized state, and oxygen is fed into the first container until the copper-containing material has reached the oxidized state. One embodiment of the invention is one, any, or all of the embodiments from the first embodiment of this paragraph to the preceding embodiments of this paragraph, wherein the heat exchanger, cooler, and heater maintain the predetermined temperature of the container through oxidation and reduction reactions.

[0041] A third embodiment of the invention is a system comprising: a first bed subjected to conditions for regenerating a copper-containing material from a reduced state to an oxidized state, wherein the first bed is configured to receive a stream comprising light olefins, hydrogen, and carbon monoxide; a second bed containing the copper-containing material, the second bed subjected to conditions for receiving a first stream comprising carbon monoxide, light olefins, and hydrogen and a second stream comprising oxygen, and subjected to conditions for converting carbon monoxide to carbon dioxide and hydrogen to water; and a third bed located downstream of the second bed, the third bed containing reduced copper-containing material to be oxidized by unconverted oxygen from the second bed. One embodiment of the invention is one, any, or all of the embodiments described in the first to the preceding embodiments of this paragraph, further comprising a control system located on the second bed to control a volume of a second oxygen stream to convert at least 95% of the carbon monoxide to carbon dioxide while minimizing the volume of oxygen leaving the second bed.

Claims

1. A method for purifying a stream containing light olefins, hydrogen, and carbon monoxide, the method comprising sending the stream and a second stream containing oxygen to one or more containers to contact a copper-containing material to remove carbon monoxide and hydrogen and produce a stream containing carbon dioxide and oxygen-free light olefins.

2. The method according to claim 1, wherein the light olefin is ethylene.

3. The method of claim 1, wherein the volume of oxygen is at a stoichiometric level of less than 100% compared to the carbon monoxide and the hydrogen.

4. The method of claim 1, wherein the bed is at a temperature of about 60°C to about 175°C.

5. The method of claim 1, wherein the stream originates from an alcohol dehydration reactor.

6. The method of claim 1, wherein the feed stream contains at least 200-2000 ppm CO and the product stream contains less than 10 ppm CO.

7. The method of claim 1, wherein the container operates at a pressure of about 200-800 psig and a GSHV of about 200-10,000 hr⁻¹.

8. The method of claim 1, wherein the carbon monoxide and the hydrogen react with the copper-containing material or oxygen to produce carbon dioxide and water.

9. A system comprising: a. A first bed, wherein the first bed is subjected to conditions that regenerate a copper-containing material from a reduced state to an oxidized state, wherein the first bed is configured to receive a stream comprising light olefins, hydrogen and carbon monoxide; b. A second bed containing copper-containing material, the second bed being subjected to conditions of receiving a first stream containing carbon monoxide, light olefins and hydrogen and a second stream containing oxygen, and being subjected to conditions of converting carbon monoxide into carbon dioxide and hydrogen into water; and c. A third bed located downstream of the second bed, the third bed containing reduced copper-containing material to be oxidized by unconverted oxygen from the second bed.

10. The system of claim 9, further comprising a control system located on the second bed to control a volume of the second oxygen flow to convert at least 95% of the carbon monoxide into carbon dioxide while minimizing the volume of oxygen leaving the second bed.

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