SERIAL METHANOL REACTORS

Abstract

The present relates to a process comprising the steps of Providing a syngas stream with module M to a Methanol loop, In the Methanol loop passing the syngas though a first Methanol reactor, obtaining a first effluent from the first Methanol reactor, Cooling the first effluent and condensing at least part of the produced methanol Separating the first cooled effluent into at least a first raw Methanol stream and a first unreacted stream, Heating the first unreacted stream, Passing the first heated unreacted stream through a second methanol reactor, Obtaining a second effluent from the second methanol reactor, Separating the second effluent into at least a second raw Methanol stream and a second unreacted stream, and Recycling the second unreacted stream to the syngas stream.

Claims

1. A process comprising the steps of providing a syngas stream with module M to a Methanol loop, in the Methanol loop passing the syngas though a first Methanol reactor, obtaining a first effluent from the first Methanol reactor, cooling the first effluent and condensing at least part of the produced methanol separating the first cooled effluent into at least a first raw Methanol stream and a first unreacted stream, heating the first unreacted stream, passing the first heated unreacted stream through a second methanol reactor, obtaining a second effluent from the second methanol reactor, cooling and condensing said second effluent, separating the cooled second effluent into at least a second raw Methanol stream and a second unreacted stream, and recycling the second unreacted stream to the syngas stream.

2. A Process according to claim 1 wherein additional steps of conversion in a methanol reactor and methanol separation is applied.

3. A Process according to claim 1 wherein the first reactor and or second reactor is a boiling water reactor (BWR), an adiabatic reactor and/or a quench reactor.

4. A Process according to claim 1 wherein the first reactor and or second reactor is operated at the same inlet temperature.

5. A Process according to claim 1 wherein the first reactor and or second reactor is operated at different inlet temperatures.

6. A Process according to claim 1 wherein the first reactor and or second reactor operated with the same or different catalyst.

7. A Process according to claim 1 wherein the process is applied as part of a revamp.

8. A plant comprising one or more Methanol loops, said methanol loop comprising at least a first and second serially connected Methanol reactors wherein a first separator is arranged downstream the first Methanol reactor and upstream the second Methanol reactor and a second separator is arranged downstream the second reactor.

9. A plant according to claim 8 comprising one or more compressors, stream cooling means and stream heating means.

10. A plant according to claim 8 arranged to carry out the steps of: providing a syngas stream with module M to the Methanol loop, in the Methanol loop passing the syngas though the first Methanol reactor, obtaining a first effluent from the first Methanol reactor, cooling the first effluent and condensing at least part of the produced methanol, separating the first cooled effluent into at least a first raw Methanol stream and a first unreacted stream, heating the first unreacted stream, passing the first heated unreacted stream through the second Methanol reactor, obtaining a second effluent from the second methanol reactor, cooling and condensing said second effluent, separating the cooled second effluent into at least a second raw Methanol stream and a second unreacted stream, and recycling the second unreacted stream to the syngas stream.

11. A method for optimizing an existing methanol loop, said method comprising the steps of introducing the process according to claim 1.

Description

[0040] In FIG. 1 a schematic of the process and Methanol loop 1 is seen. Recycle gas 2 and Make-up gas 3 is mixed to a mixed stream 4. The Mixed stream consisting of the make-up gas (synthesis gas) and recycle is heated in E1 and introduced to the 1st Methanol reactor, R1, where the gas is converted over a Cu/Zn/Al2O3 catalyst (e.g. Topsse MK-121 or MK-151 Fence) The effluent 5 from the first reactor is cooled in E1/E2, and most of the produced methanol is condensed and separated in a gas/liquid separator, V1. The vapour phase (first unreacted stream) 6 is re-heated in E3 and introduced to the 2nd Methanol reactor, R2, where the gas is converted over a catalyst such as a 64 mm Cu/Zn/Al2O3 catalyst (e.g. Topsse MK-121 or MK-151 Fence). The effluent 7 from the second reactor gas is cooled in E3/E4 and condensed methanol is separated in the gas/liquid separator, V2. The gas from the second separator is returned to the recirculator compressor 8 and compressed and recycled to the mix point 9. The condensed methanol 10, 11 from the first and second separator is led to storage and/or further treatment.

EXAMPLE: COMPARISON TO PRIOR ART

[0041] The present process is compared to prior art including WO2011101081,

Example 1

[0042] Configuration as per the present process and plant, i.e. with condensation and separation of methanol between reactors

Example 2

[0043] Configuration as per prior art i.e no separation between reactors

Example 3

[0044] Configuration as per prior art, i.e. no separation between reactors, and with higher severity (lower inlet temperature) for the catalyst

[0045] The following feed gas to 1.sup.st reactor has been used for all cases

TABLE-US-00001 1st Reactor Feed gas Pressure kg/cm2 g 84.6 Temperature C. 221 Composition mole-% H.sub.2 54.77 CO 6.92 CO.sub.2 7.34 CH.sub.4 26.00 N.sub.2 4.40 CH.sub.3OH 0.46 H.sub.2O 0.11 Total 100.00

[0046] In the following table the conversion of CO/CO.sub.2 into methanol is given. It is seen that the conversion is higher for example 1. In example 3 a higher conversion than in example 2 is obtained by a higher catalyst volume (or alternatively by a catalyst with higher activity) However, a conversion as high as for example 1 is not achieved.

TABLE-US-00002 Invention Prior art Example 1 Example 2 Example 3 1st reactor 2nd reactor 1st reactor 2nd reactor 1st reactor 2nd reactor Type BWR Adiabatic BWR Adiabatic BWR Adiabatic Outlet pressure, 82.4 76.9 82.4 76.9 82.4 77.2 kg/cm.sup.2 g Inlet 221 221 221 221 221 200 temperature, C. Outlet 253 242 253 242 253 230 temperature, C. CO/CO2 conversion 34.0% 18.4% 34.0% 8.0% 34.0% 11.2% Relative catalyst 100 100 100 100 100 173 volume (relative to catalyst volumes in invention)