Co-production of Methanol and Ammonia Without Shift Conversion
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Solution Overview
Problem
Current processes for co-producing methanol and ammonia require expensive water gas shift and carbon dioxide removal steps, leading to carbon dioxide venting to the atmosphere and high capital expenditures due to the need for complex units.
Innovation Solution
A sequential and once-through process using two parallel methanol production lines with a common catalytic methanation stage for ammonia synthesis, where carbon dioxide from flue gas is reused to produce urea, eliminating the need for water gas shift and carbon dioxide removal stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water gas shift and carbon dioxide removal steps are used in current co-production processes, then ammonia synthesis gas can be obtained, but expensive equipment and high capital expenditures are required
Solution Approach 1:
The invention extracts and removes the expensive water gas shift and carbon dioxide removal steps from the conventional co-production process. By directly using the synthesis gas from natural gas reforming for both methanol and ammonia synthesis, the process eliminates the need for separate shift conversion and CO2 removal units, thereby reducing device complexity and capital expenditures while maintaining reliable ammonia synthesis gas production
Solution Approach 2:
The invention makes the synthesis gas from natural gas reforming serve multiple functions simultaneously - it is used directly for both methanol synthesis and ammonia synthesis without requiring separate processing lines. This multi-functional use of the synthesis gas eliminates the need for dedicated water gas shift and CO2 removal equipment, reducing overall process complexity while ensuring reliable production for both chemicals
2Reliability
If water gas shift and carbon dioxide removal steps are implemented, then ammonia synthesis gas is produced, but carbon dioxide is vented to the atmosphere
Solution Approach 1:
The invention converts the harmful carbon dioxide emissions that would normally be vented to the atmosphere into a useful resource for urea production. By integrating a urea synthesis unit that uses CO2 from the natural gas reforming process, the process transforms an environmental hazard into a valuable product, eliminating CO2 emissions while maintaining reliable ammonia synthesis gas production
3Reliability
If expensive water gas shift and carbon dioxide removal units are used, then ammonia synthesis gas can be obtained, but operational costs increase due to catalyst replacement and solvent replenishment
Solution Approach 1:
The invention extracts and eliminates the expensive water gas shift and carbon dioxide removal units from the process flow. By using the synthesis gas directly for methanol and ammonia synthesis, the process removes the sources of ongoing operational costs associated with catalyst replacement and solvent replenishment, thereby improving operational cost efficiency while maintaining reliable ammonia synthesis gas production
4Reliability
If air separation units are used in the reforming section, then ammonia synthesis can be supported, but plant complexity and capital expenditure increase
Solution Approach 1:
The invention makes the natural gas reforming process serve multiple functions - it produces synthesis gas that is directly used for both methanol synthesis and ammonia synthesis without requiring separate air separation units. This multi-functional approach eliminates complex air separation equipment while ensuring reliable support for ammonia synthesis through the shared synthesis gas production
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process minimizes carbon dioxide emissions, reduces operational costs by avoiding expensive shift catalyst replacement and solvent replenishment, and achieves flexible production of methanol and ammonia without the need for air separation units, while maintaining high efficiency and flexibility in plant operations.
Implementation Method 1
producing an ammonia synthesis gas from the first and/or second gas effluent comprising nitrogen, hydrogen and unconverted carbon oxides in a common catalytic methanation stage
Implementation Method 2
catalytically converting the nitrogen and hydrogen of the ammonia synthesis gas in a common ammonia synthesis stage
Implementation Method 3
a first reforming step and first methanol conversion step obtaining a first effluent comprising methanol and a first gas effluent comprising nitrogen, hydrogen and unconverted carbon oxides
Implementation Method 4
reacting at least part of the effluent comprising ammonia with at least part of a flue gas comprising CO2 from at least one of the first and second reforming steps to produce urea
Data Source
AI summary
A process and plant for the co-production of methanol and ammonia together with urea production from a hydrocarbon feed without venting to the atmosphere carbon dioxide captured from the methanol or ammonia synthesis gas and without using expensive air separation units and water gas shift. Carbon dioxide is removed from flue gas from reforming section and used to convert partially or fully all ammonia into urea.