CN106988924A - A kind of engine thermal recovery system - Google Patents

Abstract

The invention provides an engine heat recovery system, which includes a gas engine, a heat collecting cover, a heat insulation pipe, an induced draft fan and a heat exchanger. The heat collecting cover is arranged on the upper end of the gas engine, and the There is a gap, the upper end of the heat collecting cover is connected to the heat supply fluid inlet of the heat exchanger through the heat insulation pipe, and the gas engine is connected to the power supply end of the heat exchanger to supply power for the heat exchanger, and the shale gas backflow sewage pipe is connected to the The cold fluid inlet of the heat exchanger is connected, and the waste heat of the gas engine can be used to preheat the sewage through the heat exchanger, which is convenient for subsequent sewage treatment. In order to solve the problem of large energy waste caused by the existing shale gas flowback sewage treatment method. The invention belongs to the technical field of shale gas development.

Description

A heat recovery system for an engine

technical field

The invention provides an engine waste heat recovery device for shale gas flowback sewage treatment, which belongs to the technical field of shale gas development.

Background technique

The current shale gas development technology mainly adopts hydraulic fracturing. The hydraulic fracturing method is to inject a mixture of some chemical substances, water and sediment into underground wells through high pressure, and fracture the nearby shale reservoir structure to give adsorption and The free shale gas creates pores and fracture channels, which is beneficial to the collection of shale gas. The reservoirs of shale gas reservoirs are generally characterized by low porosity and low permeability, and the resistance to gas flow is greater than that of conventional natural gas. The horizontal well drilling and hydraulic fracturing techniques necessary for shale gas development consume a lot of water, and the fracturing is completed. Finally, the fracturing fluid should be flowbacked. The COD content in the flowback sewage is extremely high, about 5,000-10,000mg/L, which is much higher than the requirements of Class I B of the national standard GB18918-1002. Due to the distribution of shale gas blocks Therefore, in the process of treating the flowback sewage, various problems such as the difficulty of uniform treatment will be encountered, so the sewage treatment of shale gas has always been a difficult problem to solve.

At present, most of the shale gas flowback sewage treatment equipment uses chemical agents, which not only do not treat the sewage thoroughly and are costly, but also cause secondary pollution to the water source, which cannot meet the national standard requirements. Instead of using chemical The treatment method of the medicament consumes too much energy, and the energy utilization rate is low, which will cause a large energy waste in the process of treatment.

Contents of the invention

The purpose of the present invention is to provide an engine heat recovery system to solve the problem of large energy waste caused by the existing shale gas flowback sewage treatment method.

In order to solve the above problems, it is planned to adopt such an engine heat recovery system, which includes a gas engine, heat collecting cover, heat insulation pipe, induced draft fan and heat exchanger. The heat collecting cover is set on the upper end of the gas engine, and the heat collecting cover There is a gap between the lower end and the ground, and the upper end of the heat collecting cover is connected to the heat supply fluid inlet of the heat exchanger through a heat insulation pipe, and the gas engine is connected to the power supply end of the heat exchanger to supply power for the heat exchanger, and the shale gas The return sewage pipeline is connected to the cold fluid inlet of the heat exchanger, and the waste heat of the gas engine can be used to preheat the sewage through the heat exchanger, which is convenient for subsequent sewage treatment.

Compared with the prior art, the present invention uses the heat emitted by the gas engine to increase the temperature of the sewage, and the waste heat is fully utilized, which improves the energy utilization rate of the system, saves energy, and reduces the cost. The wellhead for mining shale gas is generally The location is scattered and remote, and it is inconvenient to find a power source. Therefore, natural gas is used as the power source for its operation, which is easy to carry out flowback sewage treatment at different wellheads, and the treated sewage can meet the requirements of national standards.

Description of drawings

Fig. 1 is a schematic diagram of the system of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Example:

Referring to Fig. 1, an engine heat recovery system provided in this embodiment includes a gas engine 1, a heat collecting cover 2, a heat insulating pipe 3, an induced draft fan 4 and a heat exchanger 5, and the heat collecting cover 2 is set on the gas engine 1 , and there is a gap between the lower end of the heat collecting cover 2 and the ground, the upper end of the heat collecting cover 2 is connected to the heat supply fluid inlet of the heat exchanger 5 through the heat insulating pipe 3, and the gas engine 1 and the heat exchanger 5 connected to the power supply end of the heat exchanger 5 to supply power to the heat exchanger 5, and the shale gas return sewage pipeline 6 is connected to the cold fluid inlet of the heat exchanger 5, so that the waste heat of the gas engine can be used to preheat the sewage through the heat exchanger 5, which is convenient Subsequent sewage treatment.

The working principle and process of this device are as follows:

The system is used in conjunction with a steam generator and a steam compressor. After preliminary treatment, the sewage enters the heat exchanger 5. The heat exchanger 5 uses the waste heat of the gas engine 1 to heat up the returned sewage. The high-temperature returned sewage passes through the steam compressor. Pressurize and exchange heat with high-calorie steam to make it gasify and crystallize to separate pollutants and water vapor to facilitate their evaporation in the steam generator, enter the steam generator 2 for further evaporation, and remove the remaining organic matter and salts in the sewage as well as Discharged in the form of solids, such a cycle realizes the treatment of the return sewage until it reaches the national standard, and finally discharges from the heating fluid outlet of the heat exchanger 5. The treated water quality fully meets the national requirements. The sewage treatment plant needs about 10-15nm ³ natural gas to treat 1 ton of sewage, and the natural gas loss of the sewage treatment plant is about 1% of the natural gas production. The equipment is easy to install. The wellheads for mining shale gas are generally scattered and remote, and it is inconvenient to find a power source. Therefore, natural gas is used as the power source for its operation, and it is easy to carry out flowback sewage treatment at different wellheads. The treated sewage can reach national The standard requires that the waste heat of the steam generator is used to increase the temperature of the sewage, and the waste heat is utilized, which reduces the power of the steam compressor, saves energy and reduces costs.

Claims (1)

1. a kind of engine thermal recovery system, it is characterised in that：Including gas engine (1), collector mat (2), heat-insulating pipeline (3), air-introduced machine (4) and heat exchanger (5), collector mat (2) cover at the upper end of gas engine (1), and the lower end of collector mat (2) Leave gap between ground, the heat donor fluid entrance phase that the upper end of collector mat (2) passes through heat-insulating pipeline (3) and heat exchanger (5) Connect, and gas engine (1) is connected with the feeder ear of heat exchanger (5), shale gas returns sewer pipeline (6) and heat exchanger (5) Cold fluid inlet is connected.