A method for recovering heat available at low temperature in a process and its use in order to reduce the energy consumption of the said process, and application of this method to an aromatics complex in which the low-temperature heat is recovered at the head of distillation columns in the form of low-pressure steam and is reused to reboil other distillation columns in which the operating pressure has possibly been lowered.

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.

Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through mechanical vapor compression and to derive mechanical 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. Mechanical vapor compression minimizes the total energy usage. 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 duty of internal heat exchange can be flexibly adjusted without impairing energy saving performance of a HIDiC. A method of adjusting the duty of heat exchange in a heat exchange structure of a HIDiC includes totally condensing a portion of the vapor fed to a heat exchange structure in a heat exchange structure; and providing a liquid control valve downstream of the heat exchange structure on the first line, without providing a control valve on a vapor-flowing part of first and second lines of the HIDiC, and adjusting a flow rate of a portion of the compressor outlet vapor flowing into the heat exchange structure by using the control valve, while compensating for a pressure loss needed for the control valve by using a liquid head of a condensate, and/or by using pressurization by a pump.

An accelerated vapor recompression apparatus 10 converts incoming flow 35a to a concentrate 35c by developing a concentration profile 146 within a tank 30 holding a liquid 23 containing dissolved solids. The resulting curve 160 of saturation temperature of the stratified liquid 23 (such as a brine 23 or other material 23) moves away from the curve 162 corresponding to fully mixed conditions. The shift 174, 180 in saturation temperature results in increased boiling without increased energy from a heater 70 or compressor 50. A method 90, 200 of control of the system provides interventions 203, 204, 205, 206 at different levels 92, 94, 96, 98 of control, ranging from mass flows 35 to work of a compressor 50, heat from a heater 70, and a predictive processing 215 of feedback 217 for controlling commands 216 algorithmically.

A water purification unit includes an evaporator, a heat exchanger, a pump and a liquid-driven condensing ejector. A liquid inlet of the ejector is in fluid communication with an outlet of the pump. A gas inlet of the ejector is in fluid communication with a vapor outlet of the evaporator. An outlet of the ejector is in fluid communication with a fluid inlet of the heat exchanger. A fluid outlet of the heat exchanger is in fluid communication with an intake of the pump. The heat exchanger is in thermal communication with a fluid inlet to the evaporator.

Provided is a system for recovering waste heat discharged from distillation columns, incinerators, blast columns, smelting columns, and the like at relatively low temperatures to produce hot water in high efficiency, which can be used in various industrial fields. The investment and operating costs of the waste heat recovery system are relatively low as compared with the conventional systems.

An accelerated vapor recompression apparatus 10 converts incoming flow 35a to a concentrate 35c by developing a concentration profile 146 within a tank 30 holding a liquid 23 containing dissolved solids. The resulting curve 160 of saturation temperature of the stratified liquid 23 (such as a brine 23 or other material 23) moves away from the curve 162 corresponding to fully mixed conditions. The shift 174, 180 in saturation temperature results in increased boiling without increased energy from a heater 70 or compressor 50. A method 90, 200 of control of the system provides interventions 203, 204, 205, 206 at different levels 92, 94, 96, 98 of control, ranging from mass flows 35 to work of a compressor 50, heat from a heater 70, and a predictive processing 215 of feedback 217 for controlling commands 216 algorithmically.

A method is described herein, comprising vaporizing a glycol material by thermal contact with a heating medium to form a vaporized glycol stream, increasing a pressure of the vaporized glycol stream to form a pressurized glycol stream, and increasing a temperature of the heating medium by thermally contacting the heating medium with the pressurized glycol stream.

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.