摘要:
An improved process is provided for the production of nitriles and oxides from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, and ammonia where a nitrile is desired, in the presence of a suitable catalyst. An alkane, e.g. propane, is converted to an alkene in a catalytic dehydrogenator. The product stream is introduced into an ammoxidation reactor. The product formed therein is recovered in a conventional quench tower. The pressure of the gaseous effluent from the quench tower is raised and it is introduced into an absorber/stripper unit to form a recycle stream containing unreacted alkane and alkene as well as a minor amount of oxygen, typically 1-2 percent by volume, and a waste stream comprising the remainder of the quench tower gaseous phase. The recycle stream is introduced into a selective oxidation unit to remove the oxygen therefrom and then recycled to the dehydrogenator. Flammability of the quench tower gaseous effluent and the waste stream from the absorber/stripper is minimized by assuring that the nonflammability index (NFI) thereof is within certain limits. The desired NFI is related to the total hydrocarbon content of the stream and may be achieved, if required, by the addition thereto of a gaseous flame suppresor. The gaseous flame suppressor is removed with the absorber/stripper unit waste stream which may advantageously be combusted to provide energy for the process. A PSA unit may be utilized to remove excess hydrogen from the dehydrogenator effluent. The dehydrogenator may be a multistage dehydrogenator.
摘要:
An improved process for the production of oxides from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, in the presence of a suitable catalyst. An alkane, e.g. propane, is converted to an alkene in a catalytic dehydrogenator. The product stream is introduced into an oxidation reactor. Product formed therein is recovered in a conventional quench tower. The pressure of the gaseous effluent from the quench tower is raised and it is introduced into an absorber/stripper unit to form a recycle stream containing unreacted alkane and alkene as well as a minor amount of oxygen, typically 1-2 percent by volume, and a waste stream comprising the remainder of the quench tower gaseous phase. The recycle stream enters a selective oxidation unit wherein oxygen is removed, and the product recycled to the dehydrogenator. Flammability of the quench tower gaseous effluent and the waste stream from the absorber/stripper is minimized by assuring that the nonflammability index (NFI) thereof is within certain limits. Desired NFI, related to the total hydrocarbon content, may be achieved by the addition thereto of a gaseous flame suppressor. The gaseous flame suppressor, removed with the absorber/stripper unit waste stream, may advantageously be combusted to provide energy. A PSA unit may remove excess hydrogen from the dehydrogenator effluent. The dehydrogenator may be a multistage dehydrogenator.
摘要:
An improved process is provided for the production of oxides from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, in the presence of an oxidation catalyst. An alkane, e.g. propane, is converted to an alkene in a dehydrogenator. The product stream is introduced into an oxidation reactor. The product formed therein is recovered in a quench tower. The gas phase from the quench tower is treated in a PSA unit to form a gaseous stream containing the unreacted alkane, alkene, a minor amount of oxygen, i.e. less than about 2 percent by volume, and nitrogen if present in the feed to the oxidation reactor. The gaseous stream, which may or may not contain hydrogen depending on the adsorbent on the PSA unit, is introduced into a selective oxidation unit to remove the remaining oxygen and then recycled to the dehydrogenator. Hydrogen may be introduced into or removed from the PSA effluent, depending on the function of the adsorbent therein, to obtain an optimum concentration for introduction into the dehydrogenator. A preferred PSA system for use in the subject process comprises two parallel PSA units containing differnt adsorbents such that the gaseous stream formed in one PSA unit contians all of the hydrogen from the gas phase of the quench tower. The feed to the PSA units is divided disaproportionately so that the combined PSA effluent recycle streams contain the optimum concentration of hydrogen for the dehydrogenator.
摘要:
An improved process is provided for the production of nitriles from hydrocarbons by reaction with oxygen, air or gas-enriched in relative to an air, and ammonia, in the presence of an ammoxidation catalyst. An alkane, e.g. propane, is converted to an alkene in a multistage dehydrogenator. The product stream is withdrawn from a reactor in the dehydrogenator other than the first and the last reactor and introduced into an ammoxidation reactor. The product is recovered in a conventional quench tower. The gaseous effluent from the quench tower is treated in a pressure swing adsorption unit to form a gas stream containing the unreacted alkane and alkene as well as a minor amount of oxygen. The gas stream, which may or may not contain hydrogen depending on the absorbent in the pressure swing adsorption unit, is introduced into the reactor in the dehydrogenator following that from which the product stream was withdrawn. The effluent from the last reactor in the dehydrogenator is introduced into: the first reactor; an intermediate reactor wherein the alkene concentration closely approximates the effluent or the ammoxidation reactor. The subject process is particularly efficient utilizing oxygen-enriched air in the reactor feed. A particularly preferred pressure swing adsorption system for use in the subject process comprises two parallel pressure swing adsorption units containing different adsorbents such that the gas stream formed in one contains all of the hydrogen in the gas phase from the quench tower. The feed to the pressure swing adsorption units is divided disproportionately so that the conbined pressure swing adsorption effluent recycle streams contain the optimum concentration of hydrogen for the dehydrogenator.
摘要:
An improved process is provided for the production of nitriles from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, and ammonia in the presence of an ammoxidation catalyst. An alkane, e.g. propane, is converted to an alkene in a dehydrogenator. The product stream is introduced into an ammoxidation reactor. The product formed therein is recovered in a conventional quench tower. The gaseous effluent from the quench tower is treated in a PSA unit to form a gas stream containing the unreacted alkane and alkene as well as a minor amount, i.e. less than about 1 percent by volume, of oxygen and nitrogen, if present in the feed to the ammoxidation reactor. The gas stream, which may or may not contain hydrogen depending on the absorbent in the PSA unit, is introduced into a selective oxidation unit to remove the remaining oxygen and then recycled to the dehydrogenator. Hydrogen may be introduced into or removed from the PSA effluent, depending on the function of the adsorbent therein, to obtain an optimum concentration for introduction into the dehydrogenator. A particularly preferred PSA system for use in the subject process comprises two parallel PSA units containing different adsorbents such that the gas stream formed in one contains all of the hydrogen in the gas phase from the quench tower. The feed to the PSA units is divided disproportionately so that the combined PSA effluent recycle streams contain the optimum concentration of hydrogen for the dehydrogenator.
摘要:
An improved process is provided for the production of oxides from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter in the presence of an oxidation catalyst. An alkane, e.g. propane, is converted to an alkene in a catalytic dehydrogenator. The product stream is introduced into an oxidation reactor. The product formed therein is recovered in a conventional quench tower. The gaseous effluent from the quench tower is treated in a separator to produce an adsorbed stream, an oxygen-enriched stream, a waste stream and, if desired, a hydrogen-enriched stream. The oxygen-enriched stream may be recycled to the oxidation reactor depending on the nitrogen content thereof. The adsorbed stream plus at least a portion of the hydrogen-enriched stream is introduced into a selective oxidation unit to remove the remaining oxygen and then recycled to the dehydrogenator. The remainder of the hydrogen-enriched stream, if any, may be taken as product or vented. The dehydrogenator may be a multistage dehydrogenator wherein the product stream is withdrawn from a reactor other than the first and last reactors, the recycle streams are introduced into the next sequential reactor and the effluent from the last reactor is introduced into the first reactor, a reactor having a similar alkane composition or directly into the oxidation reactor.
摘要:
An improved process is provided for the production of oxides from alkanes by reaction with oxygen, air or a gas enriched in oxygen relative to an air in the presence of an oxidation catalyst. An alkane, e.g. propane, is converted to an alkene in a multistage dehydrogenator. The product stream is withdrawn from an intermediate reactor in the dehydrogenator, other than the first and the last reactor, and introduced into an oxidation reactor. The product formed in the oxidation reactor is recovered in a conventional quench tower. The gaseous effluent from the quench tower is treated in a pressure swing adsorption (PSA) unit to form a gaseous stream containing the unreacted alkane and alkene as well as a minor amount, i.e. less than about 2 percent by volume, of oxygen and nitrogen, if present in the feed to the oxidation reactor. The gaseous stream, which may or may not contain hydrogen depending on the adsorbent in the PSA unit, is introduced into the reactor in the dehydrogenator following the intermediate reactor. The effluent from the last reactor in the dehydrogenator is introduced into either: (i) the first reactor; (ii) a reactor other than said first reactor wherein the alkene concentration closely approximates the effluent of the oxidation reactor. The subject process is particularly efficient utilizing oxygen-enriched air in the reactor feed. A preferred PSA system for use in the subject process comprises two parallel PSA units containing different adsorbents such that the gaseous phase formed in one contains all of the hydrogen in the gas phase from the quench tower. The feed to the PSA units is divided disproportionately so that the combined PSA effluent recycle streams contain the optimum concentration of hydrogen for the dehydrogenator.
摘要:
An improved process is provided for the production of nitriles from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, and ammonia in the presence of an ammoxidation catalyst. An alkane, e.g., propane, is converted to an alkene in a catalytic dehydrogenator. The product stream is introduced into an ammoxidation reactor. The product formed therein is recovered in a conventional quench tower. The gaseous effluent from the quench tower is treated in a PSA unit comprising at least two pairs of adsorptive beds. The first bed forms a gas stream containing the unreacted alkane and alkene as well as a minor amount, typically 1-2 percent by volume, of oxygen and a vent stream containing oxygen, nitrogen if present, and hydrogen. The vent stream is introduced into the second adsorptive bed to thereby form an oxygen-containing stream which also contains, nitrogen, if present, and a hydrogen-enriched stream. The oxygen-containing stream may be recycled to the ammoxidation reactor depending on the nitrogen content thereof. The alkene/alkane stream plus at least a portion of the hydrogen stream is introduced into a selective oxidation unit to remove the remaining oxygen and then recycled to the dehydrogenator. The remainer of the hydrogen-enriched stream, if any, may be taken as product or vented. The dehydrogenator may be a multistage dehydrogenator wherein the product stream is withdrawn from a reactor other than the first and last reactors, the recycle streams are introduced into the next sequential reactor and the effluent from the last reactor is introduced into the first reactor, a reactor having a similar alkane composition or directly into the admmoxidation/oxidation reactor.
摘要:
The present invention relates to a process for production, shipment, and treatment of a NH4F(HF)x feedstock for local production of fluorine and NF3 for semiconductor chamber cleaning without the need for storage of large quantities of dangerous feeds and intermediate products.
摘要:
A process for the production of nitrogen trifluoride by reacting fluorine gas and liquid ammonia acid fluoride in a first reaction zone having a relatively low energy input followed by treatment of the resulting reaction product in a second reaction zone having a relatively high energy input. The resulting crude nitrogen trifluoride product may be further treated with fluorine gas under elevated temperatures to improve yield of the desired product.