Oxidative dehydrogenation (ODH) of ethane
Processes and associated reaction systems for the oxidative dehydrogenation of ethane are provided. In particular, a process is provided that comprises supplying a feed gas comprising ethane and oxygen to a multitubular fixed-bed reactor, allowing the ethane and oxygen to react in the presence of an oxidative dehydrogenation catalyst to yield a reactor effluent comprising ethylene; supplying a coolant to an upstream region of an interior shell space of the reactor in a flow pattern that is counter-current with the flow of the feed gas; and withdrawing the coolant from the upstream region and supplying at least a portion of the coolant withdrawn from the upstream region to the downstream region in a flow pattern that is co-current with the flow of the feed gas.
1. A process for the oxidative dehydrogenation of ethane to ethylene comprising:
providing a multitubular fixed-bed reactor comprising a reactor inlet, an interior shell space, a perforated partition that divides the interior shell space into an upstream region and a downstream region, and a plurality of reactor tubes, wherein the plurality of reactor tubes comprise a catalyst bed that comprises an oxidative dehydrogenation catalyst;
supplying a feed gas comprising ethane and oxygen to the reactor inlet and allowing the ethane and oxygen to react in the presence of the oxidative dehydrogenation catalyst to yield a reactor effluent comprising ethylene;
supplying a coolant to the upstream region in a flow pattern that is counter-current with the flow of the feed gas through the plurality of reactor tubes; and
withdrawing the coolant from the upstream region and supplying at least a portion of the coolant withdrawn from the upstream region to the downstream region in a flow pattern that is co-current with the flow of the feed gas through the plurality of reactor tubes,
wherein the coolant is supplied to the downstream region at a downstream coolant inlet at a downstream inlet coolant temperature and is withdrawn from the downstream region at a downstream coolant outlet at a downstream outlet coolant temperature, and wherein the downstream outlet coolant temperature exceeds the downstream inlet coolant temperature by 1 to 30° C.
2. The process of claim 1 , wherein the coolant is supplied to the upstream region at an upstream coolant inlet at an upstream inlet coolant temperature of from 250° C. to 499° C.
3. The process of claim 1 , wherein the coolant is supplied to the upstream region at an upstream coolant inlet at an upstream inlet coolant temperature of from 250° C. to 400° C.
4. The process of claim 1 , wherein the coolant is supplied to the downstream region at a downstream coolant inlet at a downstream inlet coolant temperature of from 251° C. to 500° C.
5. The process of claim 1 , wherein the coolant is supplied to the upstream region at an upstream coolant inlet at an upstream inlet coolant temperature and is withdrawn from the upstream region at an upstream coolant outlet at an upstream outlet coolant temperature, and wherein the upstream outlet coolant temperature exceeds the upstream inlet coolant temperature by 1 to 25° C.
6. The process of claim 1 , wherein the coolant is supplied to the upstream region at an upstream coolant inlet at an upstream inlet coolant temperature and is supplied to the downstream region at a downstream coolant inlet at a downstream inlet coolant temperature, and wherein the downstream inlet coolant temperature exceeds the upstream inlet coolant temperature by 1 to 25° C.
7. The process of claim 1 , wherein the upstream region is from 10 to 30% of the length of the reactor tubes.
8. The process of claim 1 , wherein the oxidative dehydrogenation catalyst in the catalyst bed has the following formula:
Mo 1 V a Te b Nb c O n
wherein:
a, b, c and n represent the ratio of the molar amount of the element in question to the molar amount of molybdenum;
a is from 0.01 to 1;
b is 0 or from >0 to 1;
c is from >0 to 1; and
n is a number which is determined by the valency and frequency of elements other than oxygen.