Ammonia Synthesis Loop Bypass Control for Stable Partial Loads
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Solution Overview
Problem
Conventional ammonia synthesis loops are not suitable for running at partial loads due to potential damage from sudden load changes and thermal instability, especially when coupled with renewable energy sources that cause rapid fluctuations in makeup gas production, necessitating large and expensive buffer tanks.
Innovation Solution
A bypass stream is introduced from the converter feed line upstream to the suction side of the circulator or downstream of the separation section, allowing the synthesis loop to maintain stable operation by splitting the circulating flow, thereby protecting the converter from fluctuations and maintaining reaction parameters constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ammonia synthesis loop runs at partial load below 60-70% capacity, then the system can adapt to renewable energy fluctuations, but the converter may suffer from thermal instability and excessive recycled ammonia preventing proper preheating
Solution Approach 1:
The feed gas stream is segmented into two paths: a main stream passing through the converter and a bypass stream circumventing it. This segmentation allows independent control of the converter inlet conditions, enabling stable operation at partial loads by maintaining adequate preheating of the main stream while accommodating variable total flow rates from renewable sources
Solution Approach 2:
A bypass stream acts as an intermediary element that mediates between the variable renewable energy input and the converter's thermal requirements. By introducing this intermediate flow path, the system can regulate the amount of gas preheated by recycled ammonia, ensuring the converter receives thermally stable feed gas even at reduced loads
2Adaptability or versatility
If a buffer tank is added to handle renewable energy fluctuations, then the synthesis loop can follow fast load changes, but the buffer tank becomes large and very expensive
Solution Approach 1:
The invention extracts the buffering function from a physical storage tank and relocates it to the gas flow dynamics within the existing loop. By using a bypass stream that can be rapidly adjusted, the system achieves load-following capability without requiring large external buffer storage, thereby eliminating the need for expensive buffer tanks while maintaining the ability to handle fast renewable energy fluctuations
3Reliability
If the start-up heater is used to sustain the reaction at partial load, then the converter can maintain reaction temperature, but the operational cost increases and the heater cannot follow fast load variations
Solution Approach 1:
The converter is designed to maintain its own reaction temperature through self-service mechanisms. The bypass stream configuration enables the system to self-regulate by adjusting the proportion of preheated feed gas entering the converter, eliminating the need for external heating assistance and allowing rapid response to load changes without the limitations of gas-fired heaters
4Reliability
If a bypass stream is introduced to maintain stable operation at partial load, then the converter is protected from fluctuations, but the device complexity increases
Solution Approach 1:
The bypass stream configuration serves multiple functions simultaneously: it protects the converter from fluctuations, enables partial load operation, provides load-following capability, and maintains thermal stability. By making the bypass system multi-functional, the added complexity is justified by the elimination of separate dedicated systems for each function, thereby reducing overall system complexity despite the initial addition of bypass infrastructure
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
The synthesis loop can operate at partial loads, including down to 20% of nominal capacity, stabilizing the converter and maintaining reaction parameters, reducing the need for additional heating and minimizing equipment damage, suitable for renewable energy sources.
Implementation Method 1
a circulator which receives the gaseous phase from the separator and serves to maintain the circulation in the loop
Implementation Method 2
a condensation section which receives the ammonia-containing gaseous product from the converter and condenses the same
Implementation Method 3
a separation section which receives the condensate from the condensation section and separates the same into a liquid ammonia product and a gaseous phase
Data Source
AI summary
A process for synthesis of ammonia including generation of makeup gas in a frontend and conversion of said makeup gas in an ammonia synthesis loop including a circulator, a converter, a condensation section and a liquid ammonia separation section, including: when the loop operates at a partial load and a flow rate of makeup gas transferred from the front end to the synthesis loop is reduced, the loop is controlled by separating a gas stream from a converter feed line at a point upstream of the converter thus forming a bypass stream, reintroducing said bypass stream at the suction side of the circulator or at a point of the loop downstream of said separation section.