A method and apparatus for producing liquefied natural gas. A portion of a natural gas stream is cooled in a heat exchanger and combined with the natural gas stream. Heavy hydrocarbons are removed from the combined natural gas stream, and the resulting separated natural gas stream is partially condensed in the first heat exchanger, with a liquid stream separated therefrom. The natural gas stream is warmed in the first heat exchanger and then is compressed and cooled. The resultant cooled compressed natural gas stream is expanded, thereby forming a chilled natural gas stream that is separated into a refrigerant stream and a non-refrigerant stream. The refrigerant stream recycled to the heat exchanger to be warmed through heat exchange with one or more process streams associated with pretreating the natural gas stream, thereby generating a warmed refrigerant stream. The warmed refrigerant stream and the non-refrigerant stream are liquefied.

An aqueous stream cleaning system including a circulation pump to receive a waste fluid and/or a concentrated liquid bottoms stream, and expel a circulation stream. The aqueous stream cleaning system can also include a primary heat exchanger to receive the circulation stream from the circulation pump. The primary heat exchanger can have a plurality of heat exchange plates that define an internal surface area for heat transfer from a distillate stream to the circulation stream to produce a cooled distillate stream and a heated circulation stream. The plurality of heat exchange plates can be spaced to facilitate free flow of solids in the circulation stream between the plurality of heat exchange plates. A mass flow rate and pressure of the circulation stream can be configured to minimize build-up of solids in the primary heat exchanger. The aqueous stream cleaning system can further include an evaporation unit to receive the heated circulation stream from the primary heat exchanger. The distillate stream is formed when steam in the heated circulation stream evaporates in the evaporation unit, and the concentrated liquid bottoms stream is formed from a portion of the heated circulation stream that does not evaporate.

Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through vapor compression and to derive mechanical, thermal, and electrical energy from a combined heat and power system, while maintaining the plant's original ability to operate. The plant's existing distillation system, steam generation, and electrical demand determine the design basis for the retrofit system that is targeted at an optimized combination of energy usage, energy cost, and environmental impact. Vapor compression (by mechanical vapor recompression and/or thermal vapor recompression) minimizes the total energy usage. Optionally, combined heat and power provides a means of converting energy between fuel, electricity, and thermal energy in a manner that best complements plant requirements and energy economics and minimizes inefficiencies and energy losses.

The present invention utilizes mechanical vapor compression and/or thermal vapor compression integrating compression loops across multiple process stages. A sequential network of compressors is utilized to increase the pressure and condensing temperature of the vapors within each process stage, as intra-vapor flow, and branching between process stages, as inter-vapor flow. Because the vapors available are shared among and between compressor stages, the number of compressors can be reduced, improving economics. Balancing vapor mass flow through incremental compressor stages which traverse multiple process stages by splitting vapors between compressor stages enables the overall vapor-compression system to be tailored to individual process energy requirements and to accommodate dynamic fluctuations in process conditions.

A process for purifying a crude composition comprising rectifying the crude composition in a rectification plant. The rectification plant comprises a rectification column including: a first overhead condenser for condensing a head fraction, and a reboiler for evaporating a bottom fraction. A difference between a temperature of the head fraction and a temperature of the bottom fraction is less than or equal to 20° C. A heat pump is provided between the first overhead condenser and the reboiler. The heat pump is an indirect heat pump that is operated with water or methanol as a refrigerant, and the indirect heat pump includes an expansion valve and a compressor. The heat pump comprises a second condenser located upstream of the compressor.

Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through vapor compression and to derive mechanical, thermal, and electrical energy from a combined heat and power system, while maintaining the plant's original ability to operate. The plant's existing distillation system, steam generation, and electrical demand determine the design basis for the retrofit system that is targeted at an optimized combination of energy usage, energy cost, and environmental impact. Vapor compression (by mechanical vapor recompression and/or thermal vapor recompression) minimizes the total energy usage. Optionally, combined heat and power provides a means of converting energy between fuel, electricity, and thermal energy in a manner that best complements plant requirements and energy economics and minimizes inefficiencies and energy losses.

The present invention utilizes mechanical vapor compression and/or thermal vapor compression integrating compression loops across multiple process stages. A sequential network of compressors is utilized to increase the pressure and condensing temperature of the vapors within each process stage, as intra-vapor flow, and branching between process stages, as inter-vapor flow. Because the vapors available are shared among and between compressor stages, the number of compressors can be reduced, improving economics. Balancing vapor mass flow through incremental compressor stages which traverse multiple process stages by splitting vapors between compressor stages enables the overall vapor-compression system to be tailored to individual process energy requirements and to accommodate dynamic fluctuations in process conditions.

This disclosure provides systems and methods that utilize integrated mechanical vapor or thermal vapor compression to upgrade process vapors and condense them to recover the heat of condensation across multiple processes, wherein the total process energy is reduced. Existing processes that are unable to recover the heat of condensation in vapors are integrated with mechanical or thermal compressors that raise vapor pressures and temperatures sufficient to permit reuse. Integrating multiple processes permits vapor upgrading that can selectively optimize energy efficiency, environmental sustainability, process economics, or a prioritized blend of such goals. Mechanical or thermal vapor compression also alters the type of energy required in industrial processes, favoring electro-mechanical energy which can be supplied from low-carbon, renewable sources rather than combustion of carbonaceous fuels.

The present invention utilizes mechanical vapor compression and/or thermal vapor compression integrating compression loops across multiple process stages. A sequential network of compressors is utilized to increase the pressure and condensing temperature of the vapors within each process stage, as intra-vapor flow, and branching between process stages, as inter-vapor flow. Because the vapors available are shared among and between compressor stages, the number of compressors can be reduced, improving economics. Balancing vapor mass flow through incremental compressor stages which traverse multiple process stages by splitting vapors between compressor stages enables the overall vapor-compression system to be tailored to individual process energy requirements and to accommodate dynamic fluctuations in process conditions.

A system and method to partially vaporize a process or feed water stream does so in a liquid pool zone of a vessel as the stream comes into contact with a heating medium that is less volatile than the process stream. To keep the pool hot, the heating medium can be recirculated through a heater of a pump-around loop or a heater can be placed in the liquid pool. As the process stream is partially vaporized, any solids present in the process stream together with the unvaporized process or feed water stream move into the heating medium. These solids and unvaporized liquids may be further removed from the heating medium in the pool or in the pump-around loop. The vaporized process stream can be further condensed. Any heat recovered can be used to pre-heat the process stream or in the pump-around loop's heater in case of mechanical vapor recovery.