Tetrahydrofuran heat pump rectification energy-saving device

Abstract

The tetrahydrofuran heat pump rectification energy-saving device comprises a first rectification tower, a second rectification tower and a third rectification tower which are connected in sequence, the bottom of the first rectifying tower is connected with a first tower bottom reboiler, the top of the first rectifying tower is connected with a first tower top heat exchanger, the bottom of the second rectifying tower is connected with a second tower bottom reboiler, the bottom of the third rectifying tower is connected with a third tower bottom reboiler, and the top of the third rectifying tower is connected with a third tower top heat exchanger; the first rectifying tower is also connected with an evaporator, a condensed water tank and a separator; according to the tetrahydrofuran heat pump rectification energy-saving device, live steam is saved, tower top gas heat energy is recycled, more economical electric energy is used as an energy consumption source, and the operation cost is low; operation is stable, and the automation degree is high; live steam with higher temperature and pressure is replaced as a heat source, and secondary steam compressed by the compressor is low in operation pressure and is safer.

Description

Technical Field

[0001] The utility model relates to the field of distillation devices, in particular to a tetrahydrofuran heat pump distillation energy-saving device. Background Art

[0002] In industrial production, distillation is an indispensable separation and purification process, and is also one of the unit operations with the largest energy consumption in production. With the rapid development of petrochemical industry, and in response to the national call for energy conservation and emission reduction, energy-saving methods for distillation towers are particularly important.

[0003] Traditional tetrahydrofuran distillation is to heat the material through the tower bottom reboiler, and the heat source is raw steam. During the distillation process, the heavy component remains at the bottom of the distillation tower, and the light component vaporizes and leaves the tower top and is cooled by cooling water, condensed into liquid and then refluxed, or used as a distillate product. From the principle of energy balance, in addition to the necessary energy consumption of converting heat energy into diffusion effective energy, most of the heat is taken out by the tower top gas phase, and is taken away by cooling water heat exchange and dissipated into the environment. In the process of cooling the tower top gas, on the one hand, the gas phase heat is lost, and on the other hand, a large amount of cooling water is consumed, resulting in a large amount of waste of energy and water. Some designs directly compress the tower top tetrahydrofuran through a compressor, and use the compressed tetrahydrofuran as a heat source. The utility model not only overcomes the deficiency of large heat energy loss in the existing distillation tower, solves the problem of heat energy loss of the tower top gas in traditional distillation, reduces the amount of raw steam used as the heat source of the tower bottom reboiler, and is a method of heat pump distillation with high efficiency and energy saving. Utility Model Content

[0004] The technical problem to be solved by the utility model is: in order to solve the problem of large heat energy loss of a distillation tower in the prior art, the utility model provides a tetrahydrofuran heat pump distillation energy-saving device.

[0005] The utility model solves the technical problem by adopting the following technical scheme: a tetrahydrofuran heat pump distillation energy-saving device, comprising a first distillation tower, a second distillation tower and a third distillation tower connected in sequence; the first distillation tower is connected to a first bottom reboiler at the bottom and to a first top heat exchanger at the top, the second distillation tower is connected to a second bottom reboiler at the bottom, the third distillation tower is connected to a third bottom reboiler at the bottom and to a third top heat exchanger at the top; the first distillation tower is also connected to an evaporator, a condensate tank and a separator.

[0006] Furthermore, an evaporator is provided between the first distillation tower and the first tower top heat exchanger, one end of the evaporator is connected to a condensate tank, and the other end is connected to a separator, and one end of the first tower top reheater is connected to a discharge pump.

[0007] Furthermore, one end of the separator is connected to the steam compressor, and the other end is connected to the condensate tank, and one end of the condensate tank is connected to the first tower bottom reboiler.

[0008] Furthermore, one end of the third tower top heat exchanger is connected to a circulation pump, and the other end of the circulation pump is connected to the third distillation tower and the second distillation tower.

[0009] Furthermore, one end of the steam compressor is connected to the third tower bottom reboiler through a pipeline.

[0010] Furthermore, the outlet end of the circulation pump is connected to the second distillation tower and the third distillation tower respectively through pipelines.

[0011] Furthermore, the steam compressor is a twin-screw compressor, a centrifugal compressor or a Roots compressor.

[0012] Beneficial effects of the utility model:

[0013] The tetrahydrofuran heat pump distillation energy-saving device described in the utility model saves raw steam, recovers the heat energy of the tower top gas, uses more economical electric energy as the energy consumption source, and has low operating costs; it operates smoothly and has a high degree of automation; it replaces the raw steam with higher temperature and pressure as the heat source, and the secondary steam compressed by the compressor has a low operating pressure and is safer. In addition, the utility model can directly design energy-saving plans according to the properties of materials such as tetrahydrofuran, and can also directly transform the existing traditional distillation tower without replacing the main equipment of the distillation tower, and does not affect the original production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0015] Figure 1 It is a schematic diagram of a tetrahydrofuran heat pump distillation energy-saving device according to a preferred embodiment of the utility model;

[0016] In the figure, 1, the first distillation tower, 2, the second distillation tower, 3, the third distillation tower, 4, the first tower bottom reboiler, 5, the first tower top heat exchanger, 6, the second tower bottom reboiler, 7, the third tower bottom reboiler, 8, the third tower top heat exchanger, 9, the evaporator, 10, the condensate tank, 11, the separator, 12, the discharge pump, 13, the steam compressor, and 14, the circulation pump. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0018] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "horizontal", "top", "inside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] like Figure 1 As shown, a tetrahydrofuran heat pump distillation energy-saving device comprises a first distillation tower 1, a second distillation tower 2 and a third distillation tower 3 connected in sequence; the first distillation tower 1 is connected to a first bottom reboiler 4 at the bottom and to a first top heat exchanger 5 at the top, the second distillation tower 2 is connected to a second bottom reboiler 6 at the bottom, the third distillation tower 3 is connected to a third bottom reboiler 7 at the bottom and to a third top heat exchanger 8 at the top; the first distillation tower 1 is also connected to an evaporator 9, a condensate tank 10 and a separator 11.

[0021] An evaporator 9 is provided between the first distillation tower 1 and the first tower top heat exchanger 5, one end of the evaporator 9 is connected to a condensate tank 10, and the other end is connected to a separator 11, and one end of the first tower top reheater is connected to a discharge pump 12. One end of the separator 11 is connected to a steam compressor 13, and the other end is connected to the condensate tank 10, and one end of the condensate tank 10 is connected to the first tower bottom reboiler 4.

[0022] One end of the third tower top heat exchanger 8 is connected to a circulation pump 14, and the other end of the circulation pump 14 is connected to the third distillation tower 3 and the second distillation tower 2. One end of the steam compressor 13 is connected to the third tower bottom reboiler 7 through a pipeline. The outlet end of the circulation pump 14 is connected to the second distillation tower 2 and the third distillation tower 3 through pipelines. The steam compressor 13 adopts a twin-screw compressor, a centrifugal compressor or a Roots compressor.

[0023] When in use, the gaseous tetrahydrofuran and water of the previous section enter the third distillation tower 3, and the tetrahydrofuran is distilled and purified, and the output liquid at the bottom of the tower is tetrahydrofuran and water. The top material of the third distillation tower 3 enters the third top heat exchanger 8 and the circulating water for heat exchange, and the condensed liquid enters the second distillation tower 2 or is pumped into the third distillation tower 3 for reflux, and the condensed liquid enters the second distillation tower 2, and the top gas of the second distillation tower 2 enters the first bottom reboiler 4, and the top gas of the second distillation tower 2 enters the top of the first distillation tower 1, and the second bottom reboiler 6 is connected to the bottom of the second distillation tower 2 for reflux, and the top material of the first distillation tower 1 is pumped into the evaporator 9 for evaporation, and the bottom material of the evaporator 9 is pumped into the first top heat exchanger 5 for heat exchange with the circulating water, and the condensed liquid tetrahydrofuran is pumped into the next section by the discharge pump 12 or pumped into the first distillation tower 1 for reflux by the discharge pump 12. The water vapor at the top of the evaporator 9 enters the separator 11, and the water vapor in the separator 11 enters the inlet of the steam compressor 13 for temperature increase and pressure increase, and the condensed water at the bottom of the evaporator 9 enters the condensed water tank 10. Since the temperature of the second distillation tower 2 is relatively high, the steam after temperature increase and pressure increase by the steam compressor 13 preferentially enters the first tower bottom reboiler 4 and the third tower bottom reboiler 7 for heating.

[0024] In this specification, the schematic representation of the terms does not necessarily refer to the same embodiment. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments.

[0025] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A tetrahydrofuran heat pump distillation energy-saving device, characterized in that: The invention comprises a first distillation tower (1), a second distillation tower (2) and a third distillation tower (3) which are connected in sequence; the first distillation tower (1) is connected to a first bottom reboiler (4) at its bottom and to a first top heat exchanger (5) at its top; the second distillation tower (2) is connected to a second bottom reboiler (6) at its bottom; the third distillation tower (3) is connected to a third bottom reboiler (7) at its bottom and to a third top heat exchanger (8) at its top; the first distillation tower (1) is also connected to an evaporator (9), a condensate tank (10) and a separator (11); An evaporator (9) is provided between the first distillation tower (1) and the first tower top heat exchanger (5), one end of the evaporator (9) is connected to a condensate tank (10), and the other end is connected to a separator (11), and one end of the first tower top reheater is connected to a discharge pump (12); One end of the separator (11) is connected to a steam compressor (13), and the other end is connected to a condensate tank (10); one end of the condensate tank (10) is connected to a first tower bottom reboiler (4); one end of the steam compressor (13) is connected to a third tower bottom reboiler (7) via a pipeline.

2. The tetrahydrofuran heat pump distillation energy-saving device according to claim 1, characterized in that: One end of the third tower top heat exchanger (8) is connected to a circulation pump (14), and the other end of the circulation pump (14) is connected to the third distillation tower (3) and the second distillation tower (2).

3. The tetrahydrofuran heat pump distillation energy-saving device according to claim 2, characterized in that, The outlet end of the circulation pump (14) is connected to the second distillation tower (2) and the third distillation tower (3) respectively through pipelines.

4. The tetrahydrofuran heat pump distillation energy-saving device according to claim 1, characterized in that: The steam compressor (13) is a twin-screw compressor, a centrifugal compressor or a Roots compressor.

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