Turbo expander

Abstract

The system is characterized by comprising a cold box, a gas-liquid separator, a heat regenerator and a turbine generator set, the cold box is provided with three outlets, one outlet of the cold box is connected with the gas-liquid separator through a pipeline, the gas-liquid separator is provided with two outlets, one outlet of the gas-liquid separator is connected with the cold box through a pipeline, and the other outlet of the gas-liquid separator is connected with the turbine generator set through a pipeline. A second outlet of the cold box is connected with a heat regenerator through a pipeline, the heat regenerator is connected with a turbine generator set through a pipeline, and the turbine generator set is connected with the cold box through a pipeline; on one hand, toluene is condensed and recovered, consumption of water vapor and electric energy is reduced, discharge of waste water is reduced, and the purposes of reducing production cost, saving energy and reducing emission are achieved. Meanwhile, the methylbenzene oxidation pressurized tail gas is used for expanding to do work to generate power, energy contained in tail gas emission is converted into electric energy, and economic benefits are created for enterprises.

Description

Technical Field

[0001] The utility model relates to the technical field of benzoic acid production, in particular to a turbo expander. Background Art

[0002] The production of benzoic acid by air oxidation of benzene is a widely used method worldwide. During the production process, a large amount of oxidation offgas containing toluene is emitted from the top of the oxidation tower. Traditionally, this offgas has been treated by condensing, separating, and recovering it with circulating water. Finally, it is adsorbed by an activated carbon adsorption system until it meets emission standards. However, desorption after adsorption by the activated carbon adsorption system consumes significant amounts of steam and electricity. Furthermore, the consumed steam and toluene gas, after cooling in the condenser, also produces a large amount of wastewater, resulting in high operating costs. To address these issues, a turboexpander has been proposed. Utility Model Content

[0003] In response to the above technical problems, the present invention provides a turboexpander, characterized in that it includes a cold box, a gas-liquid separator, a regenerator, and a turbine generator set, wherein the cold box has three outlets and three inlets, one outlet of the cold box is connected to the inlet of the gas-liquid separator through a pipeline, the gas-liquid separator has two outlets, one outlet of the gas-liquid separator is connected to the first inlet of the cold box through a pipeline, the second outlet of the cold box is connected to the regenerator through a pipeline, the regenerator is connected to the turbine generator set through a pipeline, and the turbine generator set is connected to the second inlet of the cold box through a pipeline;

[0004] The third outlet of the cold box leads to the external carbon adsorption device, another outlet of the gas-liquid separator is located at the bottom of the gas-liquid separator and is connected to the external collection device, and the third inlet of the cold box is connected to the external gas source;

[0005] The regenerator is connected to an external power source for heating, and the electric energy generated by the turbine generator set is passed to the outside.

[0006] Beneficial effects of the utility model:

[0007] On the one hand, the utility model condenses and recovers toluene, reduces the consumption of water vapor and electric energy, and reduces the discharge of wastewater, thereby achieving the purpose of reducing production costs, energy conservation and emission reduction. At the same time, the toluene oxidation pressurized tail gas is expanded to generate electricity, and the energy contained in the tail gas emissions is converted into electric energy, creating economic benefits for the enterprise. At the same time, 1. It can realize automatic constant power factor, and the grid-connected device automatically tracks the voltage, frequency and phase on the network; 2. The system is safe and reliable. When the device fails and shuts down, the quick shut-off valve quickly cuts off the gas to protect the entire device; 3. The refrigeration and power generation system has high refrigeration and power generation efficiency, and the toluene oxidation tail gas is 10,800 Nm per hour. 3 / h, can generate 260Kwh of electricity and recover about 250 kg of toluene at the same time; 4. The entire working process has almost no operating costs, and the equipment runs fully automatically and requires no supervision; 5. The entire device recovers toluene smoothly, continuously and without fluctuations; 6. There is no secondary pollution, and the recovered toluene can be directly returned to the system for use without the need for further distillation, making it an ideal energy-saving and emission-reduction device that is beneficial to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the process structure of the turbo expander of the utility model;

[0009] As shown in the figure: 1 cold box, 2 gas-liquid separator, 3 regenerator, 4 turbine generator set. DETAILED DESCRIPTION

[0010] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0011] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0012] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0013] Example 1

[0014] The utility model provides a turboexpander, characterized in that it includes a cold box 1, a gas-liquid separator 2, a regenerator 3, and a turbine generator set 4. The cold box 1 has three outlets and three inlets, one outlet of the cold box 1 is connected to the inlet of the gas-liquid separator 2 through a pipeline, the gas-liquid separator 2 has two outlets, one outlet of the gas-liquid separator 2 is connected to the first inlet of the cold box 1 through a pipeline, the second outlet of the cold box 1 is connected to the regenerator 3 through a pipeline, the regenerator 3 is connected to the turbine generator set 4 through a pipeline, and the turbine generator set 4 is connected to the second inlet of the cold box 1 through a pipeline;

[0015] Furthermore, the third outlet of the cold box 1 leads to an external carbon adsorption device, another outlet of the gas-liquid separator 2 is located at the bottom of the gas-liquid separator 2 and is connected to an external collection device, and the third inlet of the cold box 1 is connected to an external gas source;

[0016] Furthermore, the regenerator 3 is connected to an external power source for heating, and the electric energy generated by the turbine generator set 4 is passed to the outside.

[0017] Example 2

[0018] In one embodiment, the oxidation tail gas with a pressure of 470 kPa.G and a temperature of about 35°C is cooled by the 5°C cold air discharged from the gas-liquid separator 2 and the -12°C cold air discharged from the turbine through the two-in-one cold box 1. After cooling, the pressure drops to 460 kPa.G and the temperature drops to about 5°C. Then, it is separated and recovered by the gas-liquid separator 2, and the toluene C7H8 in the tail gas can be reduced to 15 g / Nm3; then, the cold energy is recovered by the cold box 1, the pressure drops to 450 kPa.G, and the temperature is heated to about 29°C. Then, it is heated by the regenerator 3 using 95°C hot water with a flow rate of 5 m3 / h, the pressure drops to 440 kPa.G, and the temperature is heated to about 72°C. Then, it is expanded and refrigerated by the turbine generator set 4, the pressure drops to 50 kPa.G, and the temperature drops to about -12°C. This cold air enters the cold box 1 and is reheated to 24°C. The reheated tail gas is finally treated by a decarbonization adsorption device.

[0019] In another embodiment, the current toluene oxidation tail gas volume is 10800Nm 3 / h. After actual operation assessment, the overall device can recycle about 300kg of toluene per hour and generate more than 260Kwh of electricity. Due to the reduction in the amount of activated carbon adsorption, the operation of 3 sets of 3 boxes of 16-core activated carbon fiber felt adsorbers can be reduced, and the use of 0.6Mpa steam can be reduced by more than 1.8 tons per hour, the discharge of wastewater can be reduced by 1.8 tons, and the electricity consumption can be reduced by 90Kw.

[0020] In another embodiment, the steam compressor produces 4.3 tons of steam per hour, and the expansion refrigeration system reduces the use of 1.8 tons of steam per hour. The reduction in boiler steam usage per hour is 4.3 tons + 1.8 tons = 6.1 tons.

[0021] Steam consumption per ton:

[0022] The fuel natural gas is about 83 cubic meters, and the unit price of natural gas is 2.7 yuan / m3.

[0023] Softened water 1 ton, unit price 5 yuan / ton,

[0024] Electricity 7Kwh,

[0025] Labor cost 12 yuan,

[0026] The unit price of steam per ton is 83x2.7+1x5+12=241.1 yuan,

[0027] The annual steam cost saving is 6.1x241.1x8000=11765680 yuan,

[0028] The sewage treatment fee is RMB 150 per ton, and the annual sewage treatment fee savings are:

[0029] 1.8x8000x150=2160000 yuan,

[0030] Annual electricity savings: [260+90] x 0.8 yuan / Kwh x 8000 = 2,240,000 yuan:

[0031] The steam compressor consumes 400Kwh of electricity per hour, and the annual electricity cost is,

[0032] 400x8000x0.8=2560000 yuan,

[0033] Reduce the operation of 3 sets of 3 boxes of 8-core activated carbon fiber felt adsorbers. The service life of activated carbon fiber felt is 3 years. The annual cost savings are 3x3x8x45Kgx300 yuan / Kg / 3 years = 324,000 yuan.

[0034] The annual economic benefits are:

[0035] 11765680+2160000+2240000-2560000+324000=13929680 yuan.

[0036] The above shows and describes the basic principles, main features and advantages of the present invention. The various components mentioned in the present invention are common technologies in the existing field. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in this utility model is defined by the appended claims and their equivalents.

Claims

1. A turboexpander, characterized in that: The invention comprises a cold box, a gas-liquid separator, a regenerator, and a turbine generator set. The cold box has three outlets and three inlets. One outlet of the cold box is connected to the inlet of the gas-liquid separator through a pipeline. The gas-liquid separator has two outlets. One outlet of the gas-liquid separator is connected to the first inlet of the cold box through a pipeline. The second outlet of the cold box is connected to the regenerator through a pipeline. The regenerator is connected to the turbine generator set through a pipeline. The turbine generator set is connected to the second inlet of the cold box through a pipeline.

2. The turbo expander according to claim 1, wherein The third outlet of the cold box leads to an external carbon adsorption device, another outlet of the gas-liquid separator is located at the bottom of the gas-liquid separator and is connected to an external collection device, and the third inlet of the cold box is connected to an external gas source.

3. The turbo expander according to claim 2, characterized in that The regenerator is connected to an external power source for heating, and the electric energy generated by the turbine generator set is passed to the outside.

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