Heat Pump Cascade for High-Temperature Ammonia Reforming
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Solution Overview
Problem
Existing heat pump technologies are limited in achieving high-temperature heat transfer for processes like ammonia cracking, requiring significant dependency on fossil fuels or direct electric heating, and there is a need to reduce this dependency on primary energy sources.
Innovation Solution
A process utilizing heat pump cascades with appropriate heat transfer media to upgrade low-temperature heat sources, achieving a coefficient of performance (COP) greater than 1, allowing heat transfer to ammonia-containing streams at very high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat pumps are used to provide heat at high temperatures for ammonia reforming, then dependency on fossil fuels and direct electric heating is reduced, but achieving temperatures significantly above 150°C has been technically limited
Solution Approach 1:
The patent divides the heat pump system into multiple compression stages (first compression unit and second compression unit) with intermediate cooling, allowing the system to achieve high temperatures (up to 500°C or more) that would be impossible in a single stage, while managing complexity through modular design
Solution Approach 2:
The patent transitions from conventional single-stage heat pumps to multi-stage compression with intercooling, adding a temporal and spatial dimension to the compression process. This allows progressive temperature elevation through multiple steps rather than attempting single-stage high-temperature compression
2Adaptability or versatility
If conventional heat sources are used for ammonia reforming, then process requirements are met, but dependency on primary energy sources and fossil fuels increases
Solution Approach 1:
The heat pump system uses electricity to drive the compression process, making the system self-sufficient and independent of external heat sources like fossil fuels. The electrical energy is converted into thermal energy through the thermodynamic compression cycle, allowing the system to serve itself without primary energy dependencies
Solution Approach 2:
The patent changes the energy input parameter from thermal (fossil fuels) to electrical, enabling flexible adaptation to renewable electricity sources. This parameter change allows the system to achieve high temperature heat with improved energy efficiency and reduced carbon footprint
3Temperature
If single-stage compression is used in heat pumps, then system complexity is reduced, but achievable temperature levels are limited to about 150°C
Solution Approach 1:
The compression process is segmented into multiple stages with intermediate cooling. The first compression unit raises the temperature to an intermediate level, the intermediate cooler reduces the temperature while removing heat, and the second compression unit further raises the temperature to the final high temperature output
Solution Approach 2:
The intermediate cooler acts as a mediator between the two compression stages. It temporarily stores and removes heat from the compressed gas, allowing the system to build up temperature progressively through staged compression rather than attempting impossible single-stage compression ratios
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 process efficiently transfers heat to ammonia streams at high temperatures, reducing dependency on primary energy sources and achieving electrical efficiency COPreal greater than 1, making it suitable for ammonia reforming and other processes.
Implementation Method 1
A process utilizing heat pump cascades with appropriate heat transfer media to upgrade low-temperature heat sources, achieving a coefficient of performance (COP) greater than 1, allowing heat transfer to ammonia-containing streams at very high temperatures
Implementation Method 2
heating comprises transferring heat from the compressed stream obtained in step (iii) to the stream provided in step (iv)
Data Source
AI summary
The present invention relates to a process for transferring heat to a stream comprising NH3, the process comprising: (i) providing a stream comprising a heat transfer medium, wherein the stream has a pressure in the range of from 1 to 100 bar(abs) and a temperature equal to or greater than 105° C.; (ii) increasing the temperature of the stream provided in (i) by transferring heat from a chemical conversion process, from a physicochemical process, or from ambient heat, or from a combination of two or more thereof, to the heat transfer medium, for obtaining a stream having a temperature in the range of from 125 to 750° C.; (iii) increasing the pressure of the stream obtained in (ii), for obtaining a compressed stream having a temperature in the range of from 50 to 800 C; (iv) providing a stream comprising NH3, wherein the stream comprising NH3 has a temperature in the range of from −33 to 100° C.; (v) heating the stream provided in (iv), wherein heating comprises transferring heat from the compressed stream obtained in (iii) to the stream provided in (iv), for obtaining a heated stream comprising NH3 having a temperature in the range of from 25 to 750° C.; (vi) expanding the compressed stream obtained in (v); (vii) optionally recycling at least a portion of the stream obtained in (vi) to (i).