The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.

The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.

A process for preparing methanol by a methanol synthesis reaction of carbon dioxide with hydrogen may involve a distillation step and a condensation step following the synthesis of a crude methanol. A volatile component and water may be separated off from a methanol-containing product stream, and a gas stream containing a volatile component that has been separated off may be discharged at least partially as offgas. At least part of the gas stream that has been separated off may be recirculated into the methanol synthesis reaction. A plant for preparing methanol can store or utilize electric power generated from renewable energy sources and provide facilities for discharging the offgas stream, which can be purified by catalytic after-combustion. Alternatively, the plant can be configured without discharge of an offgas substream, or the offgas streams are so small that they can be released without treatment into the environment at a suitable position.

A process for preparing methanol by a methanol synthesis reaction of carbon dioxide with hydrogen may involve a distillation step and a condensation step following the synthesis of a crude methanol. A volatile component and water may be separated off from a methanol-containing product stream, and a gas stream containing a volatile component that has been separated off may be discharged at least partially as offgas. At least part of the gas stream that has been separated off may be recirculated into the methanol synthesis reaction. A plant for preparing methanol can store or utilize electric power generated from renewable energy sources and provide facilities for discharging the offgas stream, which can be purified by catalytic after-combustion. Alternatively, the plant can be configured without discharge of an offgas substream, or the offgas streams are so small that they can be released without treatment into the environment at a suitable position.

A process for preparing methanol by a methanol synthesis reaction of carbon dioxide with hydrogen may involve a distillation step and a condensation step following the synthesis of a crude methanol. A volatile component and water may be separated off from a methanol-containing product stream, and a gas stream containing a volatile component that has been separated off may be discharged at least partially as offgas. At least part of the gas stream that has been separated off may be recirculated into the methanol synthesis reaction. A plant for preparing methanol can store or utilize electric power generated from renewable energy sources and provide facilities for discharging the offgas stream, which can be purified by catalytic after-combustion. Alternatively, the plant can be configured without discharge of an offgas substream, or the offgas streams are so small that they can be released without treatment into the environment at a suitable position.

Processes for making isobutanol are described. The processes involve a first reaction between methanol and ethanol in the presence of a first catalyst to produce an alcohol mixture containing propanol, isobutanol and n-butanol, and a second reaction between the produced propanol and synthesis gas in the presence of a second catalyst to produce isobutanol. The methanol and ethanol produced in the second reaction are recycled and used in the first reaction, and the unreacted propanol is recycled and used in the second reaction.

Processes for making isobutanol are described. The processes involve a first reaction between methanol and ethanol in the presence of a first catalyst to produce an alcohol mixture containing propanol, isobutanol and n-butanol, and a second reaction between the produced propanol and synthesis gas in the presence of a second catalyst to produce isobutanol. The methanol and ethanol produced in the second reaction are recycled and used in the first reaction, and the unreacted propanol is recycled and used in the second reaction.

Provided is a method for cooling a methanol r synthesis reactor effluent vapor stream in a methanol production plant, wherein the method comprises the steps of: receiving, using an inlet of a cooler, the methanol synthesis reactor effluent vapor stream from an interchanger or a methanol synthesis reactor of the methanol production plant; and spraying, using a recirculation pump connected to a spraying device, a liquid condensate received from a methanol synthesis loop onto a tube sheet of the cooler which enables direct contact of the liquid condensate with the methanol synthesis reactor effluent vapor stream and cools the methanol synthesis reactor effluent vapor stream.

Provided is a method for cooling a methanol r synthesis reactor effluent vapor stream in a methanol production plant, wherein the method comprises the steps of: receiving, using an inlet of a cooler, the methanol synthesis reactor effluent vapor stream from an interchanger or a methanol synthesis reactor of the methanol production plant; and spraying, using a recirculation pump connected to a spraying device, a liquid condensate received from a methanol synthesis loop onto a tube sheet of the cooler which enables direct contact of the liquid condensate with the methanol synthesis reactor effluent vapor stream and cools the methanol synthesis reactor effluent vapor stream.

A process for the recovery of ethylene glycol from an aqueous stream comprising ethylene glycol is disclosed. The process comprises (a) subjecting an aqueous stream 5 comprising ethylene glycol to an evaporation step in a multiple-effect evaporator to obtain a concentrated stream comprising ethylene glycol; (b) subjecting said concentrated stream comprising ethylene glycol to a first dehydration step in a first dehydrator 10 operating at an overhead pressure in the range of 0 barg (bar gauge) to 4 barg (bar gauge) to obtain a partially dehydrated ethylene glycol stream, and (c) subjecting said partially dehydrated ethylene glycol stream to a second dehydration step in a second dehydrator operating under 15 vacuum to obtain a dehydrated ethylene glycol stream.