Design of gas supply system for grain drying area at bakery

Contents

Contents

Process characteristic of grain drying process

Source Data

Brief description of grain drying process

Equipment selection and technical characteristics

gas-consuming equipment of the enterprise

Design of the enterprise gas supply system

Selection of the general gas supply scheme of the enterprise. Device

inter-mill gas pipeline

Determination of gas flow rate in gas pipeline sections

Hydraulic calculation of inter-furnace gas pipeline

Internal gas pipeline arrangement

Selection of FRG supply equipment

Selection of main equipment

Selection of additional equipment

List of literature used

Process characteristic of grain drying process

An industrial enterprise such as a bakery has an important role in the life of the population of all countries. Currently, the population of the land is increasing daily, so it is necessary to produce more and more bread products. Along with this, the problem of improving enterprises is becoming the most urgent in the world. One of the most costly parts in improving the enterprise is providing the enterprise with energy fuel. At the moment, the most economical fuel is natural gas. The advantages of gas compared to other types of fuel are: completeness of combustion, high efficiency of gas equipment, lack of soot, the ability to transport over long distances, low cost.

Natural gas is a mixture of gases formed in the bowels of the Earth during the anaerobic decomposition of organic substances, it belongs to minerals.

However, on a series of useful properties, gas, like a combustible substance, poses a certain danger: it is explosive and fire hazardous, it contains toxic substances - hydrogen sulfide, carbon monoxide. When installing and operating gas supply systems, it is necessary to take into account the requirements of SNiP "Gas Supply" (construction codes and regulations), namely: prevent its leakage in the room and the formation of explosive concentrations, ensure complete combustion of gas and removal of combustion products. To detect gas leakage, a strong odor agent, ethylmercaptan, was added in an amount of 30g per 1000m3.

Natural gas entering the PMR territory contains methane (CH4) = 92.07%, carbon dioxide (CO2) = 2%, ethane (C2H6) = 3.9%, propane (C3H8) = 0.59%, butane (C4H10) = 0.18%, pentane (C5H12) = 0.6%, nitrogen (N2) = 1.3%. Gas density

ρ = 0.796 kg/m3, density by air 0.615 kg/m3.

Selection of FRG supply equipment

Gas control stations are designed to reduce the pressure of natural gas from high and medium pressure to the required one, as well as to automatically maintain it within the specified limits, clean gas from mechanical impurities, automatically cut off gas supply at emergency increase or decrease of output pressure.

Points can be equipped with gas flow measurement systems with temperature and pressure correction, providing commercial or technological accounting of gas flow.

Depending on the excess gas pressure at the inlet, the gas control points can be medium (up to 0.3 MPa) and high pressure (0.31.2MPa).

Depending on the equipment location, gas control points are divided into several types:

- gas control station of the cabinet (GRPSH), in which the process equipment is placed in the cabinet from non-combustible materials ;

- gas control plant (GRU), in which the process equipment does not provide for the presence of its own enclosing structures, is mounted on the frame and is located on open platforms under a canopy, inside the room in which the gas-using equipment is located, or in a room connected to it by an open opening;

- gas control unit (SGB), in which process equipment is installed in one or several block-modules of container type;

- stationary gas control station (GRP), where process equipment is located in specially designed buildings, rooms or open areas.

Gas control stations and installations can be classified as follows:

- By purpose: house and industrial;

- by the number of exits: with one and two exits ;

- according to process diagrams: with one reduction line; with primary and standby reduction lines; with two reduction lines adjusted to different output pressure and two standby lines, with four reduction lines (two main, two standby); with parallel reduction, with one or two outputs.

Equipment on the GRP process line shall be located downstream in the following sequence:

- Shut-off device;

- Filter;

- Gas flow rate device;

- Safety shut-off valve (BSV);

- Pressure regulator;

- Shut-off device;

- Safety relief valve (UCS).

A gas pressure controller is a device for reducing high or medium pressure to low or medium pressure, automatically stabilizing the output pressure at a given level regardless of changes in input pressure and flow rate, as well as automatically turning off the gas supply during an emergency increase or decrease in output pressure beyond the limits of permissible established dimensions.

Gas pressure regulators shall be selected taking into account the following factors:

- type of control object;

- maximum and minimum required gas flow rate;

- maximum and minimum inlet pressure;

- maximum and minimum output pressure;

- control accuracy;

- necessity of complete tightness at regulator closing.