Gas supply of Volgograd district

1.1 Gas supply of Volgograd city district

1.1.1 Characteristics of the area

The diploma project developed gas supply to the region of the city of Volga-Grad.

Climatic data of the area: air temperature of the coldest five-day period minus 25 ° С; air temperature of the coldest days minus 30 ° С; The absolute minimum air temperature is minus 35 ° C; the duration of the heating period was 177 days; the predominant direction of the winds is northeast.

There are three types of buildings in the district: zone A - 2-3-storey buildings with a low degree of urban planning value (population density 280 people/ha), zone B - 8-9-storey buildings with a high degree of urban planning value (population density 430 people/ha), zone B - 5-storey buildings with an average degree of urban planning value (population density 330 people/ha).

Gas supply of the district is carried out by gas of the Orenburg field.

Gas is used by household consumers, utilities and industrial enterprises.

Industrial enterprises include: a medical equipment plant with a gas flow rate of 3800 m3/h, a cannery with a gas flow rate of 4200 m3/h, a Tsaritsa factory with a gas flow rate of 1350 m3/h, a Confil confectionery factory with a gas flow rate of 2780 m3/h, Gormolzavod No. 3 gas 3170 m3/h.

The necessary heat for the needs of heating, ventilation and hot water supply of the district is generated by boiler houses located in a residential building .

1.1.5 Low Pressure Gas Network Routing

In the center of each service area, the GRP is located, and from it the main paths to the boundaries of the partition area are selected, so that their lengths are approximately equal. Low-pressure networks are multi-ring, evenly distributed throughout the territory, and are laid along streets and driveways. The direction of gas movement on the line of the GRP area separation shall be the same. There should be no counter gas flows. Each quarter must be supplied with gas from two or three sides and necessarily from one long side. If this condition is not met, additional sections are laid to ensure the required reliability of the network.

On the diagram of the low pressure network, the numbers of the sections, the directions of gas movement are indicated and "zero" points are determined (meeting points of gas flows, after which the gas does not move through the distribution gas pipeline).

1.1.7 Hydraulic calculation of low-pressure gas pipelines

The calculation for the coverage areas of all GRP was carried out using the application program on the computer. The tasks of this program include: calculation of gas flows and pressure in gas networks of cities and settlements, optimal sub-selection of pipe size when designing a new gas network, the criterion of optimality is the sum of products of pipe lengths by their diameters, the program minimizes this criterion provided that the gas pressure at all points of the network does not fall below the specified value, optimal selection of pipe sizes in individual sections when calculating the existing gas network.

The design diagram of the low pressure gas pipeline distribution network is shown on the GoSN sheet 3 of the graphic part of the project.

1.1.8 Routing of the high pressure gas pipeline network

In the built-up part of cities, it is allowed to lay high-pressure pipelines of category II (up to 0.6 MPa). Gas pipelines are laid so as to supply gas to all consumers in the right amount in the shortest way, taking into account reliable consumption, for which backup of the network is provided. The network of high-pressure gas pipelines is designed single-ring with dead ends to concentrated consumers. It is recommended to lay high and low pressure gas pipelines in one trench. Therefore, when designing, where possible, gas pipelines are laid along the same driveways and streets. When designing ring networks, the network diagram is performed with two semi-rings approximately equal in length and load and a protection jumper.

1.2 Bakery gas supply

1.2.1 External gas pipeline laying conditions

high pressure

The bakery is located in the district. The objects of gas supply in the plant are a confectionery workshop with a flow rate of 100 m3/h, a bakery workshop No. 1 with a gas flow rate of 150 m3/h, a bakery workshop No. 2 with a gas flow rate of 150 m3/h, a barrack workshop with a gas flow rate of 111 m3/h, a boiler room with a flow rate of 1346 m3/h. The total gas flow to the plant is 1857 m3/h.

The plant is supplied with gas from an underground gas pipeline of high pressure category P with a diameter of 108x4. Gas pressure at the gas pipeline approach point to the plant is 0.563 MPa.

On the territory of the plant there is an above-ground laying of a gas pipeline along the walls of production buildings and on separate supports 2.5 m high, and at the places of passage of vehicles 5.0 m high. At the exit point of the gas pipeline from the ground, a case is provided and a gate valve and an insulating flange connection are installed. In addition, disconnecting devices are provided at the inlet and outlet of the cabinet gas flow metering station and before each gas-using object. Gate valves installed on the walls of buildings at the height ensuring serviceability (1.5 m) are adopted as disconnecting devices of gas-using objects.

1.2.2 Gas Flow Metering

On the territory of the plant, it is planned to take into account gas consumption separately by each consumer (workshop) and plant-wide accounting of gas consumption in PURG400 installed on the territory of the plant. Gas flow metering station consists of cabinet unit, process equipment for gas flow metering, two gas heaters with chimneys. Process equipment includes gas meter SG16M400 with gas flow rate of 2800 m3/h and hair filter FG100. The cabinet unit is a metal cabinet with thermal insulation. Doors are provided for maintenance of process equipment, for provision of natural ventilation - blinds, for heating of process equipment - heaters installed under the bottom of the cabinet unit.

The process equipment of the station consists of two lines: working and bypass. In order to clean the gas from mechanical impurities, a filter is provided in front of the meter. To correct the meter readings by the temperature and pressure of the transported gas, a pressure gauge and a self-recording pressure gauge are provided. A pressure gauge with valves is provided to visually monitor the gas pressure and measure the differential pressure across the filter. Gas is supplied to heaters via valve and gas pressure regulator. The bypass line is designed to ensure uninterrupted gas supply during repair of the working line and is equipped with a crane. For gas discharge during repair, a blowdown pipeline with a crane is provided.

1.2.4 Boiler house gas supply

The heating and production boiler house is located in a one-story freestanding building. The boiler house produces hot water with parameters of 9570 ° C for technological needs and for heating, ventilation and hot water supply of individual buildings and workshops located in the territory behind the water. Five automated hot water boilers "KSVa2.5Gs" with a capacity of 2500 kW are installed in the boiler room. The capacity of the boiler house is 12,500 MW.

Boilers "KSVa2.5Gs" are equipped with GAS 9 P/M t.s. modulation burners. with ramp DN 65 CTD. The range of gas flow by burners is from 187 to 525 m3/h. The burner is equipped with electric ignition and safety automation unit, which stops gas supply at:

Automation provides protection of the unit in the following emergency situations:

- lowering or increasing the permissible values of gas pressure before the burner;

- Flame extinguishing of the burner;

- loss of voltage in the electrical network;

- increase of furnace pressure above permissible value;

- deviation of air pressure in the air duct from the specified one;

- increase of resistance in the chimney;

- increase of water pressure at boiler outlet;

- increase of coolant temperature at boiler outlet.

The boiler burners are equipped with an additional valve tightness unit to monitor the tightness of the safety and adjustment valves of the gas ramp in case of closing of these valves. If a leak is detected, the burner is blocked.

To automatically shut off the gas supply to the boilers when the temperature of the environment in the room reaches 100 ° C in case of fire at the inlet gas line to the solenoid valve, the KTZ 001100/1.6 (f) thermal intake valve is provided.

The boiler room is provided with supply ventilation with a natural impulse, providing 3x air exchange per hour taking into account the supply air required for combustion. Inflow is carried out through the air intake unit provided in the wall behind the balls. Air removal is carried out by exhaust deflectors with a diameter of 500 mm, brought out above the roof.

The presence of natural gas (CH4) in the boiler house is monitored by RGD MET LP1 gas indicators. In case of danger, sound signal is output and gas supply is shut off by solenoid valve BH4N3. There are duplicate clock cycles for connecting secondary devices. "Alarm" signal is transmitted via modem communication to the dispatcher console.

Lightweight structures are provided due to glazing of windows.

Power supply to the boiler house is provided from the existing BRU. Supply voltage 380/220 V. Electric receivers of the boiler house are of the P category by reliability.

To ensure safety of maintenance personnel against electric shock, metal housings of electrical equipment are drilled. All normally non-current-carrying elements of electrical equipment, which may be energized in case of insulation damage, shall be occupied. Blowdown gas pipelines and gas equipment are subject to grounding, the grounding of which is required in accordance with the technical certificate for the product.

The gas pipeline is introduced into the boiler house directly into the room where the boilers are located. Common disconnecting device is installed at gas pipeline inlet. To reduce the pressure from high to medium and maintain it at a given level, the design provides for a gas control plant.

The gas pipeline inside the boiler house is laid at an elevation of 2.500 m, using supports and brackets. Disconnecting devices are installed on the branch to each boiler and at each burner. The boiler room is provided with a common blowdown gas pipeline from steel electric welded pipes with a diameter of 25x2.5 GOST 1070491. The boiler is blown through the crane and blowdown lines into the atmosphere.

Discharge blowdown pipelines (spark plugs) are provided on the boiler gas pipeline and common boiler gas pipelines, which are brought to a height of 1 m above the roof and are grounded. The gas pressure upstream of the burner is 6 kPa.

1.3 Carbon Dioxide Utilization Unit

1.3.1. Relevance of carbon dioxide utilization

Scientific and technological progress has caused many consequences that are considered environmental. There is a well-founded view that environmental deformation is a consequence of progress. First of all, this was observed with regard to the increase in concentrations of so-called "greenhouse" gases in the atmosphere. The anthropogenic impact of human activities on nature and the climate system exceeds the ability of the environment to neutralize this impact. The observed global climate change, the increase in the content of greenhouse gases in the Earth's atmosphere can be assessed as a signal of the inadmissibility of an increase in anthropogenic impact on the environment.

The sources of small gases, especially carbon dioxide and nitrogen oxides, are the burning of fossil fuels, biota. Carbon dioxide is not only a greenhouse gas. The intensity of photosynthesis depends on its content in the atmosphere, and scientists worry what it will be if the climate changes .

A large number of different scenarios for the development of energy emissions into the atmosphere have been developed, as well as the consequences of these impacts on a global scale. The concept of the greenhouse stereotype of global warming has become most widespread. There is a significant increase in anthropogenic emissions of greenhouse gases into the atmosphere.

Measures such as energy efficiency and alternative energy sources can reduce greenhouse gas emissions. However, given that 85 per cent of the world's electricity needs are met through the use of fossil fuels, the rapid elimination of such fuels without causing significant damage to the global economy is unlikely.

Given Russia's domestic consumption of fuel and energy resources, at 6% of annual GDP growth, scientists forecast an increase in greenhouse gas emissions of 442.8 million tonnes of CO2 equivalent in 2010, which will exceed by 18.2% greenhouse gas emissions in 1990. This level of increase in greenhouse gas emissions (mainly carbon dioxide and methane) necessitates the development of recycling techniques for these gases.

Methane is released as a result of agricultural activities (animal husbandry, rice cultivation), as well as due to the violation of the natural methane filter (from bacteria).

A significant amount of methane enters the atmosphere due to leaks from gas pipelines. Therefore, the World Bank approved the allocation of a $3.2 million grant to Russia for the implementation of a project to reduce natural gas leaks from pipelines to the atmosphere .

Carbon dioxide, the main component of greenhouse gases, is generated by the combustion of fossil fuels. Modelling data strongly show that the most likely limits for increasing the average annual average global temperature of surface air when the concentration of carbon dioxide doubles will be 1.5-4.5 ° C. In addition, the increased content of carbon dioxide in the air negatively affects the overall ecological state of the environment .

Scientists from different countries offer different technologies to reduce carbon dioxide emissions. One of them is the capture and geological burial of CO2. The main idea of ​ ​ the proposed technologies is the capture of carbon dioxide formed during the combustion of fossil fuels and their burial in natural reservoirs for a period of up to several thousand years. It is proposed to use natural natural reservoirs for gas storage, which have a sufficient volume to accommodate emissions accumulated over many years. Carbon dioxide capture is the most appropriate method for enterprises with large stationary sources of emission and is based on the process of separating carbon dioxide from the gas stream, both before and after the combustion process.

The application of the proposed technologies requires considerable financial costs. In addition, gas storage in natural voids is a little-controlled process and depends not only on the tightness of the surrounding rocks, but also on processes occurring in the depths of the earth's crust. Carbon dioxide to be disposed of under certain conditions (disturbance of the containment) can become a source of environmental accident due to a sharp increase in the concentration of CO2 in the nearby area. The proposed technologies are not applicable to small emission sources and require underground natural reservoirs close to production.

1.3.2 Chlorella as a carbon dioxide recycler and a valuable biological product

One method of utilising carbon dioxide from combustion of natural gas is the Chlorella vulgaris C-1 microalgae plant.

This is a microalgae that is actively used as a bioactive food additive. It is rich in high-quality nutrients, especially proteins (65-72%) and β carotene; contain important plant pigments, including chlorophyll and phycocyanin, B vitamins, iron, magnesium, selenium, rare earth minerals, enzymes, nucleotides, linoleic and linolenic acids; one of the main sources of vitamin B12.

Chlorella is very active in destroying pathogenic organisms. Essence of technological effect of processes occurring in live chlorella culture lies in the fact that in process of life activity of microalgae there is death (death) of pathogenic bacteria. This is established for all pathogenic microbes of the intestinal group (pathogens of typhoid fever, paratyph A, paratyph B and all types of dysentery), as well as for polio virus and tuberculosis pathogens.

Microalgae, releasing molecular oxygen during photosynthesis, also provide the oxidation of ammonium salts into nitrites and nitrates, which are quickly absorbed by them to build their bodies; due to this, the nitrate concentration at the outlet approaches zero. The concentration of free oxygen in the solution reaches 10 mg/l.

Chlorella is actively used to improve the ecological condition of various reservoirs, including the internal reservoirs of the Volgograd region. Strains Clorella vulgaris BIN and IFR No. C111 have well-defined plankton properties and show antagonism to blue-green algae, which makes it possible to successfully use them in the fight against the so-called "flowering" of water.

1.3.3 Patent Study of Cultivation Plants

chlorellas

To clarify the situation in the development of chlorella plants, a patent search was carried out on the basis of the Volgograd Center of the Central Research Institute. The search was carried out on archival materials until 1995 and the electronic database of CNTI from 1995 to 2007. As a result of the patent search, the following documents were investigated:

- Patent No. 2268923 Microalgae Plant

- Patent № 2000126105 Plant for Bioutilization of Agricultural Plant Effluents

- Patent № 2000117010 Methane fermentation plant

- Patent № 99101541 Disintegrator of chlorella and associations of molecules of heavy and light water

- Patent № 2002117580 Chlorella Plant

- Patent No. 2218392 Chlorella Plant

- Patent № 99105034 Symbiotenk chlorella and bacteria

- Patent № 2000117010 Methane fermentation plant

- Patent No. 2167831 Biogas Enrichment Method

- Patent No. 2163927 Fecal Waste Water Treatment Unit

The prototype for growing chlorella is patent No. 2268923 "Plant for growing microalgae." invention relates to microbiological industry, namely to technology of chlorella cultivation.

The plant for growing microalgae, in particular chlorella, includes a container for suspension of microalgae located on the frame, in which cylindrical glass shells with stationary lamps are vertically installed. Vessel is equipped with fans installed under shells and serving to supply air inside the latter when suspension temperature exceeds optimal temperature of cultivation. The plant is equipped with a suspension temperature sensor located inside the vessel and connected to it by a temperature controller connected to fans. The invention provides temperature control during microalgae cultivation and maintains it within optimal limits to increase productivity of the plant.

The proposed chlorella plant has a number of disadvantages:

- supply of nutrient solution for feeding microalgae is not considered;

- temperature sensor is located inside the container, which does not allow to control temperatures of incoming media before the container;

- air serves to cool the water in the tank, which is inefficient;

- the main disadvantage is that the author does not explain how chlorella feeds on carbon dioxide.

Based on the study, a patent application has been prepared, which proposes a chlorella growing plant, taking into account the shortcomings of previous developments.

1.3.4 Carbon Dioxide Utilization Unit

To grow chlorella, the following conditions must be maintained in the reactor volume:

temperature mode in the range of 2536 ° C ;

acidity of the medium pH = 7 ± 0.5;

illumination;

carbon dioxide concentrations (0.5-2% in starting gases);

optimal salt balance.

To obtain 1 kg of dry chlorella, it is necessary to:

350 kWh of electricity under artificial lighting ;

500 g of carbon (1.8 kg of CO2 with 1.3 kg of O2 released);

100 g of nitrogen (in the form of nitrates );

400 g of the remaining macro and trace elements ;

the volume of the cultivator (reactor) is 200 liters to obtain 1 kg per day.

The chlorella plant is a metal container with dimensions of 3.0x2.0x0.5 m (volume 3 m3). The basic diagram of the plant operation is presented on GSN8. The installation is located in a separate room adjacent to the GSV6 boiler room). Lighting of the plant is carried out using fluorescent lamps located above the tank.

The tank is filled with tap water using a 40 mm diameter pipe, the degree of filling with water of the tank is 90%.

To feed chlorella with trace elements and vitamins, a device of a nutrient device operating as a drip unit is provided. Feed solution makeup is performed continuously. The rate of solution entry into the unit is adjusted by means of a valve installed on the feed solution pipeline. At simultaneous operation of the chlorella tank unit, additional control of the solution supply is carried out with the help of valves installed on the branch to each tank.

Gas combustion products in boiler units contain about 10% carbon dioxide. A gas duct transporting combustion products with the power of the smoke pump also supplies the gas mixture to the plants. To bring the concentration and temperature of carbon dioxide to acceptable parameters, air ducts are provided that can take air both from the street and from the room where the plant is located. Control of the ratio "flue gases (carbon dioxide )/air" is carried out with the power of control dampers installed on gas ducts and air ducts. To supply carbon dioxide and air, fans are installed that are automatically connected to the control dampers. The gas-air mixture enters the lower part of the unit through pipelines with a diameter of 20 mm. The pipelines form a gas distribution grid with holes with a diameter of 5 mm, through which the gas-air mixture enters the suspension solution and bubbles, creating conditions for photosynthesis. Bubbling of the chlorella solution with a gas-air mixture promotes better mixing and, accordingly, better culture growth.

The oxygen resulting from photosynthesis is removed from the top of the plant, above which a special umbrella is located, and withdrawn outside the space for dispersion in the atmosphere. It is also possible to use the obtained oxygen to organize the combustion process in gas-burner devices of boiler units.

The time to reach the concentration of chlorella in the solution of the necessary value at the start of the plant reaches four days. The chlorella suspension can then be drained daily. Drain of finished product is provided through drain funnel installed in tank bottom. For subsequent propagation of chlorella, about 10% of the suspension remains in the reservoir, the reservoir is filled with water, and the process of growing chlorella resumes. In excess of the resulting solution, the suspension can be dried and used in winter conditions or for other needs.

When the operation of the entire system or individual tank is stopped, and if the volume of combustion products exceeds the required carbon dioxide utilization by the technological cycle, the removal of combustion products from boiler units is provided through gas ducts and chimneys located in the boiler room. In this case, the carbon dioxide of the biogas to be separated from methane is also released into the atmosphere.