ET-700 Continuous Flow Tubular Reactors Proposal

Tubular reactors are used in a continuous flow mode with reagents flowing in and products being removed. They can be the simplest of all reactor designs. Tubular reactors are often referred to by a variety of names:

Plug flow reactors

Pipe reactors

Packed-bed reactors

Fixed-bed reactors

Trickle-bed reactors

Bubble-column reactors

Ebullating-bed reactors

It is applied for (N2) (C2H4) (H2) Process Exploration. Continuous Flow Tubular Reactor Systems includes Purge Systems, Gas Feed Systems, Waste Treatment (Reaction Gas Aftertreatment System), Control System.

1, Designs & Technical Parameters:

2, Standards

GB151-2014 Heat Exchanger

GB150-2011 Pressure vessels

TSG R0004-2009 Safety Technical Supervision Regulations for Stationary Pressure Vessels

GB50093-2013 Code of Construction and Quality Acceptance for Automatic Instrument Engineering

GB/T14976　Seamless stainless steel pipe for fluid transfer

GB/T983-1995 Stainless Steel Electrode

GB/T4957-1994 Steel Wire of Fusion Welding

GB/T4958-1994 Steel Wire of Gas Shielded Welding

JB4730-94 Nondestructive Testing of Pressure Vessel

HG20580-20585-1998 Technical Regulations for Steel Chemical Containers

JB2536-80 Packages & Transportation

3, Utility

Air Supply: 0.3~0.8MPa

Power Supply: AC 220V 50Hz

4, Safety Protection

As the test works under chemical conditions, the site of Party A should be equipped with gas masks, fire extinguishers and other relevant fire-fighting equipment on site. At the same time, the workshop and test equipment need to ventilation safety protection and other aspects of strict requirements.

1, The ventilation laboratory needs to be equipped with a certain number of explosion-proof low noise axial flow fans according to the size, and start at a regular time to ensure the requirements of air exchange in the laboratory. According to the general requirements, air exchange is about 6 times per hour.

2, The cabinet using the original standard control cabinet, using non-contact solid state relays.

3, The venting device of high pressure or low pressure venting, if the amount of small can be connected to the venting; if the processing volume is large can not be directly into the atmosphere, it is necessary to increase the absorption equipment, after processing the venting.

6, Workflow and package transportation requirement.

After signing the contract, after party B receives the down payment, party B shall submit the detailed design and technical data within 15 working days, and shall be examined and approved by party A, during this period, the two sides will carry out technical exchanges from time to time; after the basic completion of the factory construction, assembly and commissioning, the two sides will jointly complete the preliminary acceptance of the factory and form a preliminary acceptance report, party a shall complete the public works supporting facilities, conduct joint commissioning, and then both parties shall complete the on-site acceptance and form a formal acceptance report The device enters the maintenance warranty period. Party B shall be responsible for the packing of the equipment. The packing box shall be tightly sealed and strong, suitable for transportation and lifting as a whole. Good protection against moisture, shock, rust and rough handling to ensure the safe delivery of goods to the user site. On arrival at the user's site, the external equipment must be kept intact and strong outer packing box.

7, Delivery and Installation

1. After signing the contract, party B shall deliver the goods according to the contract in time after receive the advance payment.

2. Party B will prepare the public works (220V electricity, water, nitrogen) advanced one week before the equipment arrived Party A＇Site.

3. Destination:

Party A Site (Party B is responsible for delivery to the site, party A is responsible for unloading)

8, Quality Assurance, Acceptance Standard and Methods

1. Party B guarantees that the equipment provided is the original product. Party B according to the technical agreement requirements to provide a complete configuration of the instrument, and ensure the normal use of the instrument.

2. Quality assurance period: from the date of acceptance on-site from the calculation of the overall system warranty for 12 months, the main hardware reactor, warranty period for 12 months.

3. During the warranty period, the maintenance cost caused by the quality problem shall be borne by party B.

4. After the instrument is installed and debugged on site, both parties shall jointly check and accept the performance of the instrument.

5. Party B guarantees that all non-standard equipment will be strength test, and issue the relevant test report

9, Technical Services

During the warranty period, if the device fails due to quality problems, Party B shall provide technical advice and support free of charge and replace the damaged parts and equipment free of charge. After the warranty period, Party B shall continue to provide instrument technical consultation and support free of charge, and supply spare parts with compensation. In the event of a problem with the user device, Party B will respond within 2 hours, provide telephone guidance, online diagnosis and troubleshooting assistance, and send technical personnel to Party A's site within 48 hours if necessary. Under special circumstances, Party B shall send technical personnel to the site of Party A within 24 hours to provide technical services.

The software is maintained for free for life, in addition to consumables, hardware equipment Warranty for 1 year.

10, PID

11, Picture reference Only

Single-phase flow in a tubular reactor can be upward or downward. Two-phase flow can be co-current up-flow, counter-current (liquid down, gas up) or, most commonly, co-current down-flow.

Tubular reactors can have a single wall and be heated with an external electric furnace or they can be jacketed for heating or cooling with a circulating heat transfer fluid. External furnaces are typically rigid, split-tube heaters. Tubular reactors are used in a variety of industries:

Petroleum

Petrochemical

Polymer

Pharmaceutical

Waste Treatment

Specialty Chemical

Alternative Energy

Tubular reactors are used in a variety of applications:

Carbonylation

Dehydrogenation

Hydrogenation

Hydrocracking

Hydroformulation

Oxidative decomposition

Partial oxidation

Polymerization

Reforming

Tubular reactors may be empty for homogenous reactions or packed with catalyst or other solid particles for heterogeneous reactions. Packed reactors require upper and lower supports to hold particles in place. Upper packing often includes inert material to serve as a pre-heat section. Pre-heating can also be done with an internal spiral channel to keep incoming reagents close to the heated wall during entry, as shown to the right.

It is often desirable to size a tubular reactor to be large enough to fit 8 to 10 catalyst particles across the diameter and be at least 40-50 particle diameters long. The length to diameter ratio can be varied to study the effect of catalyst bed length by equipping the reactor with "spools" placed in the bottom of the reactor to change this ratio.

Tubular reactor systems are highly customizable and can be made to various lengths and diameters and engineered for various pressures, temperatures and materials of construction.

A split-tube furnace is provided for heating these vessels. Insulation is provided at each end, to minimize heat loss and prevent the end caps from being heated.  The heater length is normally divided into one or three separate heating zones, although it can be split into as more zones if required.

We can furnish either a fixed internal thermocouple in each zone or a single moveable thermocouple in the center line thermowell that can be used to measure the temperature at points along the catalyst bed. External thermocouples are typically provided for control of each zone of the heater, as can be seen in the 'Open 3-Zone Split Tube Furnace" photo.

Gas Feed Systems

Various gas feeds can be set up and operated from a gas distribution rack. In order to deliver a steady flow of gas to a reactor, it is necessary to provide gas at a constant pressure to an electronic Mass Flow Controller. This instrument will compare the actual flow rate delivered to the set point chosen by the user, and automatically adjust an integral control valve to assure a constant flow. Care must be taken to size these controllers for the specific gas, flow rate range and maximum pressure of operation. A mass flow controller needs a power supply and read-out device, as well as a means of introducing the desired set point.

When ordering mass flow controllers, you will need to specify:

1. Type of gas to be metered (e.g. N2, H2, CH4)

2. Maximum operating pressure of the gas (100 or 300 bar)

3. Maximum flow rate range in standard cc's per minute (sccm)

4. Pressure for calibration of the instrument

Mass flow controllers are available for use to 1500 psi and to 4500 psi. Considerable savings can be obtained if the mass flow controller is to be used only to 1500 psi.

Schematic of a flow system with a mass flow controller.

The schematics above depicts the installation of a mass flow controller for the introduction of gas to a continuous-flow reaction system. Such installations are enhanced with the addition of a by-pass valve for rapid filling or flushing.

Schematic of a flow system with purge line.

A purge line can also be added. It is typically used for feeding nitrogen or helium to remove air before reaction or to remove reactive gases before opening the reactor at the end of a run. The purge line includes a shut-off valve, filter, metering valve, and a reverse-flow check valve.

Shut-off valves can be automated when using a E1200 Control system or E5600 Touchscreen Controller

High pressure piston pumps are most often used to inject liquids into a pressurized reactor operating in a continuous-flow mode. For low flow rates, HPLC pumps, many of which are rated for 5000 psig, are excellent choices.

Typical flow rates for pumps of this type range up to 10 or 40 mL per minute. Pumps are available to accommodate manual control from their digital faceplate or computer-control from a E1200 Process Controller.

Chemical feed pumps are our recommendation for continuous feeding of liquids when the desired flow rate is greater than 6 liters per hour. Essenton can assist with the feed pump selection. We will need to know the type of liquid; the minimum, typical, and maximum desired feed rate; the maximum operating pressure; and any special operating considerations such as explosion proof operation or corrosion possibilities.

Cooling condensers are available to cool the products of the reaction.

The reactor pressure is maintained by a Back Pressure Regulator (BPR) installed downstream of the reactor. This style of regulator will release products only when the reactor pressure exceeds a preset value by the operator.

When a BPR is used in conjunction with mass flow controllers, the user can maintain a constant flow of gas through a reactor held at an elevated constant pressure.  This provides for the highest degree of control and reproducibility in a continuous-flow reactor system.

An alternative BPR may be available to permit pressure let-down of a two-phase stream from the reactor.  This BPR requires that the operator provide a source of nitrogen or air at a pressure slightly above the desired operating pressure.  Advantages of this style is that the high-pressure Separator vessel can be replaced with a low pressure liquid product receiver and the operator will have easier access to near real-time liquid samples.

Tubular reactors operating in continuous-flow mode with both gas and liquid products will typically require a Gas/Liquid Separator. The separator is placed downstream of the reactor, often separated from the reactor by a cooling condenser. In the separator vessel, liquids are condensed and collected in the bottom of the vessel. Gases and non-condensed vapors are allowed to leave the top of the vessel and pass to the back pressure regulator. It is important to operate the standard BPR with a single fluid phase to prevent oscillation of the reactor pressure.

The Gas/Liquid Separator can be sized large enough to act as a liquid product receiver that is drained periodically. Many of the non-stirred pressure vessels made by Essenton are ideally suited for use as Gas/Liquid Separators. Vessels of 300, 600, 1000, or 2000 mL are commonly chosen. Upon request, the bottom of the separator can be tapered to facilitate draining and/or automatic liquid drain capability can be added.

Essenton's new laboratory-scale automated solids-feed module is designed to continuously deliver free-flowing non-cohesive bulk solids into specially customized Essenton continuous stirred, tubular, or fluidized bed reactors.

Control and Data Acquisition Systems

A variety of solutions exist to meet the needs of system operators. System accessories such as heaters, mass flow controllers, and pumps can be obtained with individual control packages to create a manual, Distributed Control System (DCS) based on our 4838 and 4848 Controllers.

As the number of channels to be controlled increases, economics and convenience will often dictate that the distributed system of individual controllers should be replaced with the computer-based Model E1200 Process Controller (PCC).

Below are schematic representations of typical tubular reactor systems, along with a symbols chart to facilitate understanding. We have provided an ordering number for each of these examples